66 results on '"Walsh SK"'
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2. GPR55 EXERTS DIFFERENTIAL EFFECTS ON CARDIAC ADRENOCEPTOR SUBTYPES IN MICE
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Walsh, SK, primary and Wainwright, CL, additional
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- 2014
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3. EXOGENOUS LYSOPHOSPHATIDOLINOSITOL EXACERBATES MYOCARDIAL TISSUE INJURY VIA A GPR55 DEPENDENT MECHANISM
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Robertson-Gray, OJ, primary, Walsh, SK, additional, Jönsson-Rylander, AC, additional, and Wainwright, CL, additional
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- 2014
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4. Contribution of PARP to endothelial dysfunction and hypertension in a rat model of pre-eclampsia
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Walsh, SK, primary, English, FA, additional, Crocker, IP, additional, Johns, EJ, additional, and Kenny, LC, additional
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- 2012
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5. Mast cell degranulation - a mechanism for the anti-arrhythmic effect of endothelin-1?
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Walsh, SK, primary, Kane, KA, additional, and Wainwright, CL, additional
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- 2009
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6. Get set, get wet, go!
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Walsh SK
- Published
- 2000
7. An axis-specific mitral annuloplasty ring eliminates mitral regurgitation allowing mitral annular motion in an ovine model.
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Zhu Y, Imbrie-Moore AM, Park MH, Cork TE, Yajima S, Wilkerson RJ, Tran NA, Marin-Cuartas M, Mullis DM, Baker SW, Tada Y, Ueyama T, Leipzig M, Wang VY, Ethiraj S, Madira S, Anilkumar S, Walsh SK, Lucian HJ, Huynh C, Morris K, Kim OS, Mulligan J, Wang H, Shudo Y, Ennis DB, and Woo YJ
- Abstract
Introduction: Current mitral annuloplasty rings fail to restrict the anteroposterior distance while allowing dynamic mitral annular changes. We designed and manufactured a mitral annuloplasty ring that demonstrated axis-specific, selective flexibility to meet this clinical need. The objectives were to evaluate ex vivo biomechanics of this ring and to validate the annular dynamics and safety after ring implantation in vivo., Methods: Healthy human mitral annuli (n = 3) were tracked, and motions were isolated. Using the imaging data, we designed and manufactured our axis-specific mitral annuloplasty ring. An ex vivo annular dilation model was used to compare hemodynamics and chordal forces after repair using the axis-specific, rigid, and flexible rings in five porcine mitral valves. In vivo, axis-specific (n = 6), rigid (n = 6), or flexible rings (n = 6) were implanted into male Dorset sheep for annular motion analyses. Five additional animals receiving axis-specific rings survived for up to 6 months., Results: Here we show the axis-specific, rigid, and flexible rings reduced regurgitation fraction to 4.7 ± 2.7%, 2.4 ± 3.2%, and 17.8 ± 10.0%, respectively. The axis-specific ring demonstrated lower average forces compared to the rigid ring (p = 0.046). Five animals receiving axis-specific rings survived for up to 6 months, with mitral annular motion preserved in vivo. Mature neoendocardial tissue coverage over the device was found to be complete with full endothelialization in all animals., Conclusions: The axis-specific mitral annuloplasty ring we designed demonstrates excellent capability to repair mitral regurgitation while facilitating dynamic mitral annular motion. This ring has tremendous potential for clinical translatability, representing a promising surgical solution for mitral regurgitation., Competing Interests: Competing interests: The authors declare the following competing interests: Y.J.W., Y.Z., A.M.I.-M., M.H.P., and M.J.P. filed a provisional US patent (application number 18/094,213) and PCT application (application number PCT/US21/41803). The device design and manufacturing are covered in patent application., (© 2025. The Author(s).)
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- 2025
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8. Short-Term Oral Administration of the Porcupine Inhibitor, Wnt-c59, Improves the Structural and Functional Features of Experimental HFpEF.
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Paul MA, Wainwright CL, Hector EE, Ryberg E, Leslie SJ, and Walsh SK
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- Animals, Male, Mice, Administration, Oral, Membrane Proteins metabolism, Cardiomegaly drug therapy, Stroke Volume drug effects, Diet, High-Fat adverse effects, Pyridines, Benzeneacetamides, Heart Failure drug therapy, Disease Models, Animal, Wnt Signaling Pathway drug effects, Acyltransferases antagonists & inhibitors, Mice, Inbred C57BL, Fibrosis
- Abstract
Heart failure with preserved ejection fraction (HFpEF) accounts for approximately 50% of heart failure cases globally, and this incidence is increasing due to extended lifespans and accumulating comorbidities. Emerging evidence suggests that Wnt signaling plays a role in cardiomyocyte hypertrophy and cardiac fibrosis, which are key features of HFpEF. Furthermore, Porcupine (PORCN) inhibitors, which negatively regulate Wnt signaling, have shown promising results in improving cardiac function and reducing cardiac hypertrophy and/or fibrosis. This study investigated whether acute oral administration of the PORCN inhibitor, Wnt-c59, alters the maladaptive structural and/or functional features in a mouse model of HFpEF. Male mice were given a high-fat diet and L-NAME (0.5 g L
-1 ) in drinking water for 5 weeks, followed by a 2-week intervention of orally administered Wnt-c59 (5 mg kg-1 day-1 ). HFpEF mice were characterized by hypertension, cardiac hypertrophy and fibrosis, and diastolic dysfunction, although there was no evidence of activation of Wnt signaling in the heart. Despite this, short-term treatment of HFpEF mice with Wnt-c59 ameliorated adverse cardiac remodeling by increasing the ratio of the more compliant collagen type 3 to that of the more tensile collagen type 1 in the heart. Furthermore, Wnt-c59 also improved diastolic dysfunction, which was associated with the increased cardiac expression of brain natriuretic peptide, a known promoter of ventricular compliance. Our findings demonstrate that even short-term administration of a PORCN inhibitor improves both the structural and functional features of experimental HFpEF., (© 2025 The Author(s). Pharmacology Research & Perspectives published by British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics and John Wiley & Sons Ltd.)- Published
- 2025
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9. Pharmacology of Non-Psychoactive Phytocannabinoids and Their Potential for Treatment of Cardiometabolic Disease.
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Wainwright CL and Walsh SK
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- Humans, Animals, Cannabis chemistry, Cardiovascular Diseases drug therapy, Metabolic Diseases drug therapy, Metabolic Diseases metabolism, Endocannabinoids metabolism, Cannabinoids pharmacology, Cannabinoids therapeutic use
- Abstract
The use of Cannabis sativa by humans dates back to the third millennium BC, and it has been utilized in many forms for multiple purposes, including production of fibre and rope, as food and medicine, and (perhaps most notably) for its psychoactive properties for recreational use. The discovery of Δ
9 -tetrahydrocannabinol (Δ9 -THC) as the main psychoactive phytocannabinoid contained in cannabis by Gaoni and Mechoulam in 1964 (J Am Chem Soc 86, 1646-1647), was the first major step in cannabis research; since then the identification of the chemicals (phytocannabinoids) present in cannabis, the classification of the pharmacological targets of these compounds and the discovery that the body has its own endocannabinoid system (ECS) have highlighted the potential value of cannabis-derived compounds in the treatment of many diseases, such as neurological disorders and cancers. Although the use of Δ9 -THC as a therapeutic agent is constrained by its psychoactive properties, there is growing evidence that non-psychoactive phytocannabinoids, derived from both Cannabis sativa and other plant species, as well as non-cannabinoid compounds found in Cannabis sativa, have real potential as therapeutics. This chapter will focus on the possibilities for using these compounds in the prevention and treatment of cardiovascular disease and related metabolic disturbances., (© 2025. The Author(s), under exclusive license to Springer Nature Switzerland AG.)- Published
- 2025
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10. Minimally invasive valve-sparing aortic root replacement via an upper mini-sternotomy in a young adult with Marfan syndrome.
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Walsh SK, Mubashir M, and Said SM
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- Humans, Adolescent, Aortic Valve surgery, Male, Blood Vessel Prosthesis Implantation methods, Female, Marfan Syndrome complications, Marfan Syndrome surgery, Marfan Syndrome diagnosis, Sternotomy methods, Minimally Invasive Surgical Procedures methods
- Abstract
We describe an upper mini-sternotomy for valve-sparing aortic root replacement in a teenager., (© The Author 2024. Published by MMCTS on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
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- 2024
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11. Pollen banking is a critical need for conserving plant diversity.
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Wolkis D, Eltringham C, Fant J, Foster J, Knight T, Meyer A, Romero-Saltos H, Walsh SK, Wood A, and Havens K
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- Conservation of Natural Resources, Plants, Biodiversity, Pollen
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- 2024
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12. The impact of insect herbivory on biogeochemical cycling in broadleaved forests varies with temperature.
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Hwang BC, Giardina CP, Adu-Bredu S, Barrios-Garcia MN, Calvo-Alvarado JC, Dargie GC, Diao H, Duboscq-Carra VG, Hemp A, Hemp C, Huasco WH, Ivanov AV, Johnson NG, Kuijper DPJ, Lewis SL, Lobos-Catalán P, Malhi Y, Marshall AR, Mumladze L, Ngute ASK, Palma AC, Petritan IC, Rordriguez-Cabal MA, Suspense IA, Zagidullina A, Andersson T, Galiano-Cabrera DF, Jiménez-Castillo M, Churski M, Gage SA, Filippova N, Francisco KS, Gaglianese-Woody M, Iankoshvili G, Kaswamila MA, Lyatuu H, Mampouya Wenina YE, Materu B, Mbemba M, Moritz R, Orang K, Plyusnin S, Puma Vilca BL, Rodríguez-Solís M, Šamonil P, Stępniak KM, Walsh SK, Xu H, and Metcalfe DB
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- Animals, Carbon metabolism, Carbon Cycle, Phosphorus metabolism, Ecosystem, Trees metabolism, Herbivory physiology, Forests, Insecta physiology, Temperature, Plant Leaves metabolism, Nitrogen metabolism
- Abstract
Herbivorous insects alter biogeochemical cycling within forests, but the magnitude of these impacts, their global variation, and drivers of this variation remain poorly understood. To address this knowledge gap and help improve biogeochemical models, we established a global network of 74 plots within 40 mature, undisturbed broadleaved forests. We analyzed freshly senesced and green leaves for carbon, nitrogen, phosphorus and silica concentrations, foliar production and herbivory, and stand-level nutrient fluxes. We show more nutrient release by insect herbivores at non-outbreak levels in tropical forests than temperate and boreal forests, that these fluxes increase strongly with mean annual temperature, and that they exceed atmospheric deposition inputs in some localities. Thus, background levels of insect herbivory are sufficiently large to both alter ecosystem element cycling and influence terrestrial carbon cycling. Further, climate can affect interactions between natural populations of plants and herbivores with important consequences for global biogeochemical cycles across broadleaved forests., (© 2024. The Author(s).)
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- 2024
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13. Large Animal Translational Validation of 3 Mitral Valve Repair Operations for Mitral Regurgitation Using a Mitral Valve Prolapse Model: A Comprehensive In Vivo Biomechanical Engineering Analysis.
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Zhu Y, Yajima S, Park MH, Venkatesh A, Stark CJ, Tran NA, Walsh SK, Ethiraj S, Wilkerson RJ, Lin LE, Lee SH, Gates KY, Arthur JD, Baker SW, Mullis DM, Wu CA, Harima S, Pokhrel B, Resuello D, Bergamasco H, Wu MA, Baccouche BM, Pandya PK, Elde S, Wang H, and Woo YJ
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- Humans, Male, Animals, Sheep, Mitral Valve diagnostic imaging, Mitral Valve surgery, Chordae Tendineae surgery, Treatment Outcome, Mitral Valve Insufficiency diagnostic imaging, Mitral Valve Insufficiency surgery, Mitral Valve Prolapse diagnostic imaging, Mitral Valve Prolapse surgery, Heart Valve Prosthesis Implantation methods
- Abstract
Background: Various mitral repair techniques have been described. Though these repair techniques can be highly effective when performed correctly in suitable patients, limited quantitative biomechanical data are available. Validation and thorough biomechanical evaluation of these repair techniques from translational large animal in vivo studies in a standardized, translatable fashion are lacking. We sought to evaluate and validate biomechanical differences among different mitral repair techniques and further optimize repair operations using a large animal mitral valve prolapse model., Methods: Male Dorset sheep (n=20) had P2 chordae severed to create the mitral valve prolapse model. Fiber Bragg grating force sensors were implanted to measure chordal forces. Ten sheep underwent 3 randomized, paired mitral valve repair operations: neochord repair, nonresectional leaflet remodeling, and triangular resection. The other 10 sheep underwent neochord repair with 2, 4, and 6 neochordae. Data were collected at baseline, mitral valve prolapse, and after each repair., Results: All mitral repair techniques successfully eliminated regurgitation. Compared with mitral valve prolapse (0.54±0.18 N), repair using neochord (0.37±0.20 N; P =0.02) and remodeling techniques (0.30±0.15 N; P =0.001) reduced secondary chordae peak force. Neochord repair further decreased primary chordae peak force (0.21±0.14 N) to baseline levels (0.20±0.17 N; P =0.83), and was associated with lower primary chordae peak force compared with the remodeling (0.34±0.18 N; P =0.02) and triangular resectional techniques (0.36±0.27 N; P =0.03). Specifically, repair using 2 neochordae resulted in higher peak primary chordal forces (0.28±0.21 N) compared with those using 4 (0.22±0.16 N; P =0.02) or 6 neochordae (0.19±0.16 N; P =0.002). No difference in peak primary chordal forces was observed between 4 and 6 neochordae ( P =0.05). Peak forces on the neochordae were the lowest using 6 neochordae (0.09±0.11 N) compared with those of 4 neochordae (0.15±0.14 N; P =0.01) and 2 neochordae (0.29±0.18 N; P =0.001)., Conclusions: Significant biomechanical differences were observed underlying different mitral repair techniques in a translational large animal model. Neochord repair was associated with the lowest primary chordae peak force compared to the remodeling and triangular resectional techniques. Additionally, neochord repair using at least 4 neochordae was associated with lower chordal forces on the primary chordae and the neochordae. This study provided key insights about mitral valve repair optimization and may further improve repair durability., Competing Interests: Disclosures None.
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- 2024
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14. Variability in seed salinity tolerance in an island coastal community.
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Walsh SK, Wolkis D, Abbriano RM, and Barton KE
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- Germination, Seeds physiology, Plants, Salinity, Water, Ecosystem, Salt Tolerance
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Background and Aims: Islands, with their long coastlines and increased vulnerability to sea level rise, offer compelling opportunities to investigate the salinity tolerance of coastal plants. Seeds are generally more vulnerable than other plant stages to increased stressors. The aim of this study was to characterize salinity tolerance during germination across a diverse pool of 21 species from 14 plant families found in coastal communities throughout the Hawaiian Islands in order to increase our general understanding of coastal plant ecology for conservation and restoration., Methods: Seeds of each species were exposed to unfiltered/untreated seawater (35 ppt total salinity) and two salinity treatments (10 and 20 ppt) in which the seawater was diluted with distilled water, and germination percent and timing were compared to seeds in a distilled water control. Non-germinated seeds were then tested for recovery germination. We quantified and compared germination percent, time and recovery among species and across salinity levels and tested for heterogeneity related to seed size, dormancy class, habit and threatened status., Key Results: Although salinity tolerance varied considerably among species, salinity exposure generally reduced and delayed germination. The greatest effects were detected at higher salinity levels. Recovery germination overall was higher for seeds that had been exposed to higher salinity. None of the factors we explored emerged as predictors of salinity tolerance except seed mass, which tended to enhance germination at higher salinity., Conclusions: Species responses to salinity exposure indicate high vulnerability of coastal systems to increased salinity stress, and variability among species could lead to shifts in community assembly and composition under sea level rise. These results can help guide coastal ecosystem conservation and restoration management decisions in the face of climate change., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2023
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15. Biomechanics and clinical outcomes of various conduit configurations in valve sparing aortic root replacement.
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Zhu Y, Park MH, Pandya PK, Stark CJ, Mullis DM, Walsh SK, Kim JY, Wu CA, Baccouche BM, Lee SH, Baraka AS, Joo H, Yajima S, Elde S, and Woo YJ
- Abstract
Background: Several conduit configurations, such as straight graft (SG), Valsalva graft (VG), anticommissural plication (ACP), and the Stanford modification (SMOD) technique, have been described for the valve-sparing aortic root replacement (VSARR) procedure. Prior ex vivo studies have evaluated the impact of conduit configurations on root biomechanics, but the mock coronary artery circuits used could not replicate the physical properties of native coronary arteries. Moreover, the individual leaflet's biomechanics, including the fluttering phenomenon, were unclear., Methods: Porcine aortic roots with coronary arteries were explanted (n=5) and underwent VSARR using SG, VG, ACP, and SMOD for evaluation in an ex vivo left heart flow loop simulator. Additionally, 762 patients who underwent VSARR from 1993 through 2022 at our center were retrospectively reviewed. Analysis of variance was performed to evaluate differences between different conduit configurations, with post hoc Tukey's correction for pairwise testing., Results: SG demonstrated lower rapid leaflet opening velocity compared with VG (P=0.001) and SMOD (P=0.045) in the left coronary cusp (LCC), lower rapid leaflet closing velocity compared with VG (P=0.04) in the right coronary cusp (RCC), and lower relative opening force compared with ACP (P=0.04) in the RCC. The flutter frequency was lower in baseline compared with VG (P=0.02) and in VG compared with ACP (P=0.03) in the LCC. Left coronary artery mean flow was higher in SG compared with SMOD (P=0.02) and ACP (P=0.05). Clinically, operations using SG compared with sinus-containing graft was associated with shorter aortic cross-clamp and cardiopulmonary bypass time (P<0.001, <0.001)., Conclusions: SG demonstrated hemodynamics and biomechanics most closely recapitulating those from the native root with significantly shorter intraoperative times compared with repair using sinus-containing graft. Future in vivo validation studies as well as correlation with comprehensive, comparative clinical study outcomes may provide additional invaluable insights regarding strategies to further enhance repair durability., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2023 Annals of Cardiothoracic Surgery. All rights reserved.)
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- 2023
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16. The host phylogeny determines viral infectivity and replication across Staphylococcus host species.
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Walsh SK, Imrie RM, Matuszewska M, Paterson GK, Weinert LA, Hadfield JD, Buckling A, and Longdon B
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- Host Specificity, Phylogeny, Polymerase Chain Reaction, Staphylococcus aureus virology, Viral Plaque Assay, Virus Replication, Bacteriophages physiology, Staphylococcaceae classification, Staphylococcaceae virology, Staphylococcus Phages physiology
- Abstract
Virus host shifts, where a virus transmits to and infects a novel host species, are a major source of emerging infectious disease. Genetic similarity between eukaryotic host species has been shown to be an important determinant of the outcome of virus host shifts, but it is unclear if this is the case for prokaryotes where anti-virus defences can be transmitted by horizontal gene transfer and evolve rapidly. Here, we measure the susceptibility of 64 strains of Staphylococcaceae bacteria (48 strains of Staphylococcus aureus and 16 non-S. aureus species spanning 2 genera) to the bacteriophage ISP, which is currently under investigation for use in phage therapy. Using three methods-plaque assays, optical density (OD) assays, and quantitative (q)PCR-we find that the host phylogeny explains a large proportion of the variation in susceptibility to ISP across the host panel. These patterns were consistent in models of only S. aureus strains and models with a single representative from each Staphylococcaceae species, suggesting that these phylogenetic effects are conserved both within and among host species. We find positive correlations between susceptibility assessed using OD and qPCR and variable correlations between plaque assays and either OD or qPCR, suggesting that plaque assays alone may be inadequate to assess host range. Furthermore, we demonstrate that the phylogenetic relationships between bacterial hosts can generally be used to predict the susceptibility of bacterial strains to phage infection when the susceptibility of closely related hosts is known, although this approach produced large prediction errors in multiple strains where phylogeny was uninformative. Together, our results demonstrate the ability of bacterial host evolutionary relatedness to explain differences in susceptibility to phage infection, with implications for the development of ISP both as a phage therapy treatment and as an experimental system for the study of virus host shifts., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Walsh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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17. Investigating the outcomes of virus coinfection within and across host species.
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Imrie RM, Walsh SK, Roberts KE, Lello J, and Longdon B
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- Animals, Drosophila melanogaster genetics, Host Specificity, Host-Pathogen Interactions genetics, Coinfection, Dicistroviridae
- Abstract
Interactions between coinfecting pathogens have the potential to alter the course of infection and can act as a source of phenotypic variation in susceptibility between hosts. This phenotypic variation may influence the evolution of host-pathogen interactions within host species and interfere with patterns in the outcomes of infection across host species. Here, we examine experimental coinfections of two Cripaviruses-Cricket Paralysis Virus (CrPV), and Drosophila C Virus (DCV)-across a panel of 25 Drosophila melanogaster inbred lines and 47 Drosophilidae host species. We find that interactions between these viruses alter viral loads across D. melanogaster genotypes, with a ~3 fold increase in the viral load of DCV and a ~2.5 fold decrease in CrPV in coinfection compared to single infection, but we find little evidence of a host genetic basis for these effects. Across host species, we find no evidence of systematic changes in susceptibility during coinfection, with no interaction between DCV and CrPV detected in the majority of host species. These results suggest that phenotypic variation in coinfection interactions within host species can occur independently of natural host genetic variation in susceptibility, and that patterns of susceptibility across host species to single infections can be robust to the added complexity of coinfection., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Imrie et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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18. Outcomes of Heart Transplantation Using a Temperature-controlled Hypothermic Storage System.
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Zhu Y, Shudo Y, He H, Kim JY, Elde S, Williams KM, Walsh SK, Koyano TK, Guenthart B, and Woo YJ
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- Humans, Ischemia prevention & control, Proportional Hazards Models, Retrospective Studies, Temperature, Treatment Outcome, Male, Female, Adult, Middle Aged, Survival Analysis, Heart Transplantation methods, Heart Transplantation statistics & numerical data, Tissue and Organ Procurement methods, Tissue and Organ Procurement standards
- Abstract
Background: The SherpaPak Cardiac Transport System is a novel technology that provides stable, optimal hypothermic control during organ transport. The objectives of this study were to describe our experience using the SherpaPak system and to compare outcomes after heart transplantation after using SherpaPak versus the conventional static cold storage method (non-SherpaPak)., Methods: From 2018 to June 2021, 62 SherpaPak and 186 non-SherpaPak patients underwent primary heart transplantation at Stanford University with follow-up through May 2022. The primary end point was all-cause mortality, and secondary end points were postoperative complications. Optimal variable ratio matching, cox proportional hazards regression model, and Kaplan-Meier survival analyses were performed., Results: Before matching, the SherpaPak versus non-SherpaPak patients were older and received organs with significantly longer total allograft ischemic time. After matching, SherpaPak patients required fewer units of blood product for perioperative transfusion compared with non-SherpaPak patients but otherwise had similar postoperative outcomes such as hospital length of stay, primary graft dysfunction, inotrope score, mechanical circulatory support use, cerebral vascular accident, myocardial infarction, respiratory failure, new renal failure requiring dialysis, postoperative bleeding or tamponade requiring reoperation, infection, and survival., Conclusions: In conclusion, this is one of the first retrospective comparison studies that evaluated the outcomes of heart transplantation using organs preserved and transported via the SherpaPak system. Given the excellent outcomes, despite prolonged total allograft ischemic time, it may be reasonable to adopt the SherpaPak system to accept organs from a remote location to further expand the donor pool., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2023
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19. Three-Dimensional Bioprinting with Alginate by Freeform Reversible Embedding of Suspended Hydrogels with Tunable Physical Properties and Cell Proliferation.
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Zhu Y, Stark CJ, Madira S, Ethiraj S, Venkatesh A, Anilkumar S, Jung J, Lee S, Wu CA, Walsh SK, Stankovich GA, and Woo YJ
- Abstract
Extrusion-based three-dimensional (3D) bioprinting is an emerging technology that allows for rapid bio-fabrication of scaffolds with live cells. Alginate is a soft biomaterial that has been studied extensively as a bio-ink to support cell growth in 3D constructs. However, native alginate is a bio-inert material that requires modifications to allow for cell adhesion and cell growth. Cells grown in modified alginates with the RGD (arginine-glycine-aspartate) motif, a naturally existing tripeptide sequence that is crucial to cell adhesion and proliferation, demonstrate enhanced cell adhesion, spreading, and differentiation. Recently, the bioprinting technique using freeform reversible embedding of suspended hydrogels (FRESH) has revolutionized 3D bioprinting, enabling the use of soft bio-inks that would otherwise collapse in air. However, the printability of RGD-modified alginates using the FRESH technique has not been evaluated. The associated physical properties and bioactivity of 3D bio-printed alginates after RGD modification remains unclear. In this study, we characterized the physical properties, printability, and cellular proliferation of native and RGD-modified alginate after extrusion-based 3D bioprinting in FRESH. We demonstrated tunable physical properties of native and RGD-modified alginates after FRESH 3D bioprinting. Sodium alginate with RGD modification, especially at a high concentration, was associated with greatly improved cell viability and integrin clustering, which further enhanced cell proliferation.
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- 2022
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20. The Origin of Internal Genes Contributes to the Replication and Transmission Fitness of H7N9 Avian Influenza Virus.
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James J, Bhat S, Walsh SK, Karunarathna TK, Sadeyen JR, Chang P, Sealy JE, Mahmood S, Mollett BC, Slomka MJ, Brookes SM, and Iqbal M
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- Animals, Humans, Chickens, Reassortant Viruses genetics, Poultry, Phylogeny, Influenza in Birds, Influenza A Virus, H7N9 Subtype genetics, Influenza A Virus, H9N2 Subtype genetics, Coinfection, Influenza, Human
- Abstract
H9N2 avian influenza viruses (AIVs) have donated internal gene segments during the emergence of zoonotic AIVs, including H7N9. We used reverse genetics to generate A/Anhui/1/13 (H7N9) and three reassortant viruses (2:6 H7N9) which contained the hemagglutinin and neuraminidase from Anhui/13 (H7N9) and the six internal gene segments from H9N2 AIVs belonging to (i) G1 subgroup 2, (ii) G1 subgroup 3, or (iii) BJ94 lineages, enzootic in different regions throughout Asia. Infection of chickens with the 2:6 H7N9 containing G1-like H9N2 internal genes conferred attenuation in vivo , with reduced shedding and transmission to contact chickens. However, possession of BJ94-like H9N2 internal genes resulted in more rapid transmission and significantly elevated cloacal shedding compared to the parental Anhui/13 H7N9. In vitro analysis showed that the 2:6 H7N9 with BJ94-like internal genes had significantly increased replication compared to the Anhui/13 H7N9 in chicken cells. In vivo coinfection experiments followed, where chickens were coinfected with pairs of Anhui/13 H7N9 and a 2:6 H7N9 reassortant. During ensuing transmission events, the Anhui/13 H7N9 virus outcompeted 2:6 H7N9 AIVs with internal gene segments of BJ94-like or G1-like H9N2 viruses. Coinfection did lead to the emergence of novel reassortant genotypes that were transmitted to contact chickens. Some of the reassortant viruses had a greater replication in chicken and human cells compared to the progenitors. We demonstrated that the internal gene cassette determines the transmission fitness of H7N9 viruses in chickens, and the reassortment events can generate novel H7N9 genotypes with increased virulence in chickens and enhanced zoonotic potential. IMPORTANCE H9N2 avian influenza viruses (AIVs) are enzootic in poultry in different geographical regions. The internal genes of these viruses can be exchanged with other zoonotic AIVs, most notably the A/Anhui/1/2013-lineage H7N9, which can give rise to new virus genotypes with increased veterinary, economic and public health threats to both poultry and humans. We investigated the propensity of the internal genes of H9N2 viruses (G1 or BJ94) in the generation of novel reassortant H7N9 AIVs. We observed that the internal genes of H7N9 which were derivative of BJ94-like H9N2 virus have a fitness advantage compared to those from the G1-like H9N2 viruses for efficient transmission among chickens. We also observed the generation of novel reassortant viruses during chicken transmission which infected and replicated efficiently in human cells. Therefore, such emergent reassortant genotypes may pose an elevated zoonotic threat.
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- 2022
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21. Supporting long-term sustainability of ex situ collections using a pedigree-based population management approach.
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Foster JA, Walsh SK, Havens K, Kramer AT, and Fant JB
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Premise: Living collections maintained for generations are at risk of diversity loss, inbreeding, and adaptation to cultivation. To address these concerns, the zoo community uses pedigrees to track individuals and implement crosses that maximize founder contributions and minimize inbreeding. Using a pedigree management approach, we demonstrate how conducting strategic crosses can minimize genetic issues that have arisen under current practices., Methods: We performed crosses between collections and compared progeny fitness, including plant performance and reproductive health. We genotyped the progeny and parental accessions to measure changes in diversity and relatedness within and between accessions., Results: The mean relatedness values among individuals within each accession suggest they are full siblings, demonstrating that there was high inbreeding and low diversity within accessions, although less so among accessions. Progeny from the wider crosses had increased genetic diversity and were larger and more fertile, while self-pollinated accessions were smaller and less fertile., Discussion: Institutions that hold exceptional species should consider how diversity is maintained within their collections. Implementing a pedigree-based approach to managing plant reproduction ex situ will slow the inevitable loss of genetic diversity and, in turn, result in healthier collections., (© 2022 The Authors. Applications in Plant Sciences published by Wiley Periodicals LLC on behalf of Botanical Society of America.)
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- 2022
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22. Extinction risk of the endemic vascular flora of Kauai, Hawaii, based on IUCN assessments.
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Rønsted N, Walsh SK, Clark M, Edmonds M, Flynn T, Heintzman S, Loomis A, Lorence D, Nagendra U, Nyberg B, Opgenorth M, Weisenberger L, Williams A, Wolkis D, Wood KR, and Keir M
- Subjects
- Animals, Biodiversity, Extinction, Biological, Hawaii, Plants, Conservation of Natural Resources methods, Endangered Species
- Abstract
The International Union for Conservation of Nature's Red List of Threatened Species (IUCN Red List) is the world's most comprehensive information source on the global conservation status of species. Governmental agencies and conservation organizations increasingly rely on IUCN Red List assessments to develop conservation policies and priorities. Funding agencies use the assessments as evaluation criteria, and researchers use meta-analysis of red-list data to address fundamental and applied conservation science questions. However, the circa 143,000 IUCN assessments represent a fraction of the world's biodiversity and are biased in regional and organismal coverage. These biases may affect conservation priorities, funding, and uses of these data to understand global patterns. Isolated oceanic islands are characterized by high endemicity, but the unique biodiversity of many islands is experiencing high extinction rates. The archipelago of Hawaii has one of the highest levels of endemism of any floristic region; 90% of its 1367 native vascular plant taxa are classified as endemic. We used the IUCN's assessment of the complete single-island endemic (SIE) vascular plant flora of Kauai, Hawaii, to assess the proportion and drivers of decline of threatened plants in an oceanic island setting. We compared the IUCN assessments with federal, state, and other local assessments of Kauai species or taxa of conservation concern. Finally, we conducted a preliminary assessment for all 1044 native vascular plants of Hawaii based on IUCN criterion B by estimating area of occupancy, extent of occurrence, and number of locations to determine whether the pattern found for the SIE vascular flora of Kauai is comparable to the native vascular flora of the Hawaiian Islands. We compared our results with patterns observed for assessments of other floras. According to IUCN, 256 SIE vascular plant taxa are threatened with extinction and 5% are already extinct. This is the highest extinction risk reported for any flora to date. The preliminary assessment of the native vascular flora of Hawaii showed that 72% (753 taxa) is threatened. The flora of Hawaii may be one of the world's most threatened; thus, increased and novel conservation measures in the state and on other remote oceanic islands are urgently needed., (© 2022 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)
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- 2022
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23. Maturation- and degeneration-dependent articular cartilage metabolism via optical redox ratio imaging.
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Walsh SK, Soni R, Arendt LM, Skala MC, and Henak CR
- Subjects
- Animals, Chondrocytes metabolism, Flavin-Adenine Dinucleotide analysis, Flavin-Adenine Dinucleotide metabolism, NAD analysis, NAD metabolism, Oxidation-Reduction, Swine, Cartilage, Articular metabolism
- Abstract
From the two metabolic processes in healthy cartilage, glycolysis has been associated with proliferation and oxidative phosphorylation (oxphos) with matrix synthesis. Recently, metabolic dysregulation was significantly correlated with cartilage degradation and osteoarthritis progression. While these findings suggest maturation predisposes cartilage to metabolic instability with consequences for tissue maintenance, these links have not been shown. Therefore, this study sought to address three hypotheses (a) chondrocytes exhibit differential metabolic activity between immaturity (0-4 months), adolescence (5-18 months), and maturity (>18 months); (b) perturbation of metabolic activity has consequences on expression of genes pertinent to cartilage tissue maintenance; and (c) severity of cartilage damage is positively correlated with glycolysis and oxphos activity as well as optical redox ratio in postadolescent cartilage. Porcine femoral cartilage samples from pigs (3 days to 6 years) underwent optical redox ratio imaging, which measures autofluorescence of NAD(P)H and FAD. Gene expression analysis and histological scoring was conducted for comparison against imaging metrics. NAD(P)H and FAD autofluorescence both demonstrated increasing intensity with age, while optical redox ratio was lowest in adolescent samples compared to immature or mature samples. Inhibition of glycolysis suppressed expression of Col2, Col1, ADAMTS4, and ADAMTS5, while oxphos inhibition had no effect. FAD fluorescence and optical redox ratio were positively correlated with histological degeneration. This study demonstrates maturation- and degeneration-dependent metabolic activity in cartilage and explores the consequences of this differential activity on gene expression. This study aids our basic understanding of cartilage biology and highlights opportunity for potential diagnostic applications., (© 2021 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)
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- 2022
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24. A novel photosynthetic biologic topical gel for enhanced localized hyperoxygenation augments wound healing in peripheral artery disease.
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Zhu Y, Jung J, Anilkumar S, Ethiraj S, Madira S, Tran NA, Mullis DM, Casey KM, Walsh SK, Stark CJ, Venkatesh A, Boakye A, Wang H, and Woo YJ
- Subjects
- Gels, Humans, Ischemia, Oxygen, Photosynthesis, Wound Healing, Biological Products, Peripheral Arterial Disease therapy
- Abstract
Peripheral artery disease and the associated ischemic wounds are substantial causes of global morbidity and mortality, affecting over 200 million people worldwide. Although advancements have been made in preventive, pharmacologic, and surgical strategies to treat this disease, ischemic wounds, a consequence of end-stage peripheral artery disease, remain a significant clinical and economic challenge. Synechococcus elongatus is a cyanobacterium that grows photoautotrophically and converts carbon dioxide and water into oxygen. We present a novel topical biologic gel containing S. elongatus that provides oxygen via photosynthesis to augment wound healing by rescuing ischemic tissues caused by peripheral artery disease. By using light rather than blood as a source of energy, our novel topical therapy significantly accelerated wound healing in two rodent ischemic wound models. This novel topical gel can be directly translated to clinical practice by using a localized, portable light source without interfering with patients' daily activities, demonstrating potential to generate a paradigm shift in treating ischemic wounds from peripheral artery disease. Its novelty, low production cost, and ease of clinical translatability can potentially impact the clinical care for millions of patients suffering from peripheral arterial disease., (© 2022. The Author(s).)
- Published
- 2022
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25. Microbiome-based interventions to modulate gut ecology and the immune system.
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Hitch TCA, Hall LJ, Walsh SK, Leventhal GE, Slack E, de Wouters T, Walter J, and Clavel T
- Subjects
- Prebiotics, Immune System, Microbiota, Gastrointestinal Microbiome, Probiotics
- Abstract
The gut microbiome lies at the intersection between the environment and the host, with the ability to modify host responses to disease-relevant exposures and stimuli. This is evident in how enteric microbes interact with the immune system, e.g., supporting immune maturation in early life, affecting drug efficacy via modulation of immune responses, or influencing development of immune cell populations and their mediators. Many factors modulate gut ecosystem dynamics during daily life and we are just beginning to realise the therapeutic and prophylactic potential of microbiome-based interventions. These approaches vary in application, goal, and mechanisms of action. Some modify the entire community, such as nutritional approaches or faecal microbiota transplantation, while others, such as phage therapy, probiotics, and prebiotics, target specific taxa or strains. In this review, we assessed the experimental evidence for microbiome-based interventions, with a particular focus on their clinical relevance, ecological effects, and modulation of the immune system., (© 2022. The Author(s).)
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- 2022
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26. Resistant starch-An accessible fiber ingredient acceptable to the Western palate.
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Walsh SK, Lucey A, Walter J, Zannini E, and Arendt EK
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- Bread, Dietary Fiber, Palate metabolism, Resistant Starch, Starch
- Abstract
Dietary fiber intakes in Western societies are concerningly low and do not reflect global recommended dietary fiber intakes for chronic disease prevention. Resistant starch (RS) is a fermentable dietary fiber that has attracted research interest. As an isolated ingredient, its fine particle size, relatively bland flavor, and white appearance may offer an appealing fiber source to the Western palate, accustomed to highly refined, processed grains. This review aims to provide a comprehensive insight into the current knowledge (classification, production methods, and characterization methods), health benefits, applications, and acceptability of RS. It further discusses the present market for commercially available RS ingredients and products containing ingredients high in RS. The literature currently highlights beneficial effects for dietary RS supplementation with respect to glucose metabolism, satiety, blood lipid profiles, and colonic health. An exploration of the market for commercial RS ingredients indicates a diverse range of products (from isolated RS2, RS3, and RS4) with numerous potential applications as partial or whole substitutes for traditional flour sources. They may increase the nutritional profile of a food product (e.g., by increasing the fiber content and lowering energy values) without significantly compromising its sensory and functional properties. Incorporating RS ingredients into staple food products (such as bread, pasta, and sweet baked goods) may thus offer an array of nutritional benefits to the consumer and a highly accessible functional ingredient to be greater exploited by the food industry., (© 2022 The Authors. Comprehensive Reviews in Food Science and Food Safety published by Wiley Periodicals LLC on behalf of Institute of Food Technologists.)
- Published
- 2022
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27. Coinfection of Chickens with H9N2 and H7N9 Avian Influenza Viruses Leads to Emergence of Reassortant H9N9 Virus with Increased Fitness for Poultry and a Zoonotic Potential.
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Bhat S, James J, Sadeyen JR, Mahmood S, Everest HJ, Chang P, Walsh SK, Byrne AMP, Mollett B, Lean F, Sealy JE, Shelton H, Slomka MJ, Brookes SM, and Iqbal M
- Subjects
- Animals, Chickens, Ferrets, Humans, Influenza, Human, Phylogeny, Poultry, Coinfection veterinary, Influenza A Virus, H7N9 Subtype genetics, Influenza A Virus, H9N2 Subtype genetics, Influenza in Birds virology, Reassortant Viruses genetics, Reassortant Viruses pathogenicity
- Abstract
An H7N9 low-pathogenicity avian influenza virus (LPAIV) emerged in 2013 through genetic reassortment between H9N2 and other LPAIVs circulating in birds in China. This virus causes inapparent clinical disease in chickens, but zoonotic transmission results in severe and fatal disease in humans. To examine a natural reassortment scenario between H7N9 and G1 lineage H9N2 viruses predominant in the Indian subcontinent, we performed an experimental coinfection of chickens with A/Anhui/1/2013/H7N9 (Anhui/13) virus and A/Chicken/Pakistan/UDL-01/2008/H9N2 (UDL/08) virus. Plaque purification and genotyping of the reassortant viruses shed via the oropharynx of contact chickens showed H9N2 and H9N9 as predominant subtypes. The reassortant viruses shed by contact chickens also showed selective enrichment of polymerase genes from H9N2 virus. The viable "6+2" reassortant H9N9 (having nucleoprotein [NP] and neuraminidase [NA] from H7N9 and the remaining genes from H9N2) was successfully shed from the oropharynx of contact chickens, plus it showed an increased replication rate in human A549 cells and a significantly higher receptor binding to α2,6 and α2,3 sialoglycans compared to H9N2. The reassortant H9N9 virus also had a lower fusion pH, replicated in directly infected ferrets at similar levels compared to H7N9 and transmitted via direct contact. Ferrets exposed to H9N9 via aerosol contact were also found to be seropositive, compared to H7N9 aerosol contact ferrets. To the best of our knowledge, this is the first study demonstrating that cocirculation of H7N9 and G1 lineage H9N2 viruses could represent a threat for the generation of novel reassortant H9N9 viruses with greater virulence in poultry and a zoonotic potential. IMPORTANCE We evaluated the consequences of reassortment between the H7N9 and the contemporary H9N2 viruses of the G1 lineage that are enzootic in poultry across the Indian subcontinent and the Middle East. Coinfection of chickens with these viruses resulted in the emergence of novel reassortant H9N9 viruses with genes derived from both H9N2 and H7N9 viruses. The "6+2" reassortant H9N9 (having NP and NA from H7N9) virus was shed from contact chickens in a significantly higher proportion compared to most of the reassortant viruses, showed significantly increased replication fitness in human A549 cells, receptor binding toward human (α2,6) and avian (α2,3) sialic acid receptor analogues, and the potential to transmit via contact among ferrets. This study demonstrated the ability of viruses that already exist in nature to exchange genetic material, highlighting the potential emergence of viruses from these subtypes with zoonotic potential.
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- 2022
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28. GPR55 regulates the responsiveness to, but does not dimerise with, α 1A -adrenoceptors.
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Walsh SK, Lipina C, Ang SY, Sato M, Chia LY, Kocan M, Hutchinson DS, Summers RJ, and Wainwright CL
- Subjects
- Adrenergic alpha-1 Receptor Agonists pharmacology, Animals, Animals, Newborn, CHO Cells, Cells, Cultured, Cricetinae, Cricetulus, Female, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Organ Culture Techniques, Pregnancy, Protein Multimerization drug effects, Rats, Rats, Sprague-Dawley, Protein Multimerization physiology, Receptors, Adrenergic, alpha-1 genetics, Receptors, Adrenergic, alpha-1 metabolism, Receptors, Cannabinoid deficiency, Receptors, Cannabinoid genetics
- Abstract
Emerging evidence suggests that G protein coupled receptor 55 (GPR55) may influence adrenoceptor function/activity in the cardiovascular system. Whether this reflects direct interaction (dimerization) between receptors or signalling crosstalk has not been investigated. This study explored the interaction between GPR55 and the alpha 1A-adrenoceptor (α
1A -AR) in the cardiovascular system and the potential to influence function/signalling activities. GPR55 and α1A -AR mediated changes in both cardiac and vascular function was assessed in male wild-type (WT) and GPR55 homozygous knockout (GPR55-/- ) mice by pressure volume loop analysis and isolated vessel myography, respectively. Dimerization of GPR55 with the α1A -AR was examined in transfected Chinese hamster ovary-K1 (CHO-K1) cells via Bioluminescence Resonance Energy Transfer (BRET). GPR55 and α1A -AR mediated signalling (extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation) was investigated in neonatal rat ventricular cardiomyocytes using AlphaScreen proximity assays. GPR55-/- mice exhibited both enhanced pressor and inotropic responses to A61603 (α1A -AR agonist), while in isolated vessels, A61603 induced vasoconstriction was attenuated by a GPR55-dependent mechanism. Conversely, GPR55-mediated vasorelaxation was not altered by pharmacological blockade of α1A -ARs with tamsulosin. While cellular studies demonstrated that GPR55 and α1A -AR failed to dimerize, pharmacological blockade of GPR55 altered α1A -AR mediated signalling and reduced ERK1/2 phosphorylation. Taken together, this study provides evidence that GPR55 and α1A -AR do not dimerize to form heteromers, but do interact at the signalling level to modulate the function of α1A -AR in the cardiovascular system., (Copyright © 2021 Elsevier Inc. All rights reserved.)- Published
- 2021
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29. Applying the zoo model to conservation of threatened exceptional plant species.
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Wood J, Ballou JD, Callicrate T, Fant JB, Griffith MP, Kramer AT, Lacy RC, Meyer A, Sullivan S, Traylor-Holzer K, Walsh SK, and Havens K
- Subjects
- Animals, Gardening, Plants genetics, Seeds, Conservation of Natural Resources, Endangered Species
- Abstract
Maintaining a living plant collection is the most common method of ex situ conservation for plant species that cannot be seed banked (i.e., exceptional species). Viability of living collections, and their value for future conservation efforts, can be limited without coordinated efforts to track and manage individuals across institutions. Using a pedigree-focused approach, the zoological community has established an inter-institutional infrastructure to support long-term viability of captive animal populations. We assessed the ability of this coordinated metacollection infrastructure to support the conservation of 4 plant species curated in living collections at multiple botanic gardens around the world. Limitations in current practices include the inability to compile, share, and analyze plant collections data at the individual level, as well as difficulty in tracking original provenance of ex situ material. The coordinated metacollection framework used by zoos can be adopted by the botanical community to improve conservation outcomes by minimizing the loss of genetic diversity in collections. We suggest actions to improve ex situ conservation of exceptional plant species, including developing a central database to aggregate data and track unique individuals of priority threatened species among institutions and adapting a pedigree-based population management tool that incorporates life-history aspects unique to plants. If approached collaboratively across regional, national, and global scales, these actions could transform ex situ conservation of threatened plant species., (© 2020 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology.)
- Published
- 2020
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30. Mechanobiology of Cartilage Impact Via Real-Time Metabolic Imaging.
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Walsh SK, Shelley JC, and Henak CR
- Subjects
- Animals, Swine, Biomechanical Phenomena, Optical Imaging, Flavin-Adenine Dinucleotide metabolism, Oxidation-Reduction, Mechanical Phenomena, Time Factors, Weight-Bearing, Stress, Mechanical, Cartilage, Articular metabolism, Cartilage, Articular diagnostic imaging
- Abstract
Cartilage loading is important in both structural and biological contexts, with overloading known to cause osteoarthritis (OA). Cellular metabolism, which can be evaluated through the relative measures of glycolysis and oxidative phosphorylation, is important in disease processes across tissues. Details of structural damage coupled with cellular metabolism in cartilage have not been evaluated. Therefore, the aim of this study was to characterize the time- and location-dependent metabolic response to traumatic impact loading in articular cartilage. Cartilage samples from porcine femoral condyles underwent a single traumatic injury that created cracks in most samples. Before and up to 30 min after loading, samples underwent optical metabolic imaging. Optical metabolic imaging measures the fluorescent intensity of byproducts of the two metabolic pathways, flavin adenine dinucleotide for oxidative phosphorylation and nicotinamide adenine dinucleotide ± phosphate for glycolysis, as well as the redox ratio between them. Images were taken at varied distances from the center of the impact. Shortly after impact, fluorescence intensity in both channels decreased, while redox ratio was unchanged. The most dramatic metabolic response was measured closest to the impact center, with suppressed fluorescence in both channels relative to baseline. Redox ratio varied nonlinearly as a function of distance from the impact. Finally, both lower and higher magnitude loading reduced flavin adenine dinucleotide fluorescence, whereas reduced nicotinamide adenine dinucleotide ± phosphate fluorescence was associated only with low strain loads and high contact pressure loads, respectively. In conclusion, this study performed novel analysis of metabolic activity following induction of cartilage damage and demonstrated time-, distance-, and load-dependent response to traumatic impact loading., (Copyright © 2020 by ASME.)
- Published
- 2020
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31. Maturity-dependent cartilage cell plasticity and sensitivity to external perturbation.
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Walsh SK, Schneider SE, Amundson LA, Neu CP, and Henak CR
- Subjects
- Animals, Cell Plasticity, Chondrocytes, Chondrogenesis genetics, Swine, Cartilage, Articular, Osteoarthritis genetics
- Abstract
Objective: Articular cartilage undergoes biological and morphological changes throughout maturation. The prevalence of osteoarthritis in the aged population suggests that maturation predisposes cartilage to degradation and/or impaired regeneration, but this process is not fully understood. Therefore, the objective of this study was to characterize the cellular and genetic profile of cartilage, as well as biological plasticity in response to mechanical and culture time stimuli, as a function of animal maturity., Methods/design: Porcine articular cartilage explants were harvested from stifle joints of immature (2-4 weeks), adolescent (5-6 months), and mature (1-5 years) animals. Half of all samples were subjected to a single compressive mechanical load. Loaded samples were paired with unloaded controls for downstream analyses. Expression of cartilage progenitor cell markers CD105, CD44, and CD29 were determined via flow cytometry. Expression of matrix synthesis genes Col1, Col2, Col10, ACAN, and SOX9 were determined via qPCR. Tissue morphology and matrix content were examined histologically. Post-loading assays were performed immediately and following 7 days in culture., Results: CD105 and CD29 expression decreased with maturity, while CD44 expression was upregulated in cartilage from mature animals. Expression of matrix synthesis genes were generally upregulated in cartilage from mature animals, and adolescent animals showed the lowest expression of several matrix synthesizing genes. Culture time and mechanical loading analyses revealed greater plasticity to mechanical loading and culture time in cartilage from younger animals. Histology confirmed distinct structural and biochemical profiles across maturity., Conclusion: This study demonstrates differential, nonlinear expression of chondroprogenitor markers and matrix synthesis genes as a function of cartilage maturity, as well as loss of biological plasticity in aged tissue. These findings have likely implications for age-related loss of regeneration and osteoarthritis progression., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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32. Real-time optical redox imaging of cartilage metabolic response to mechanical loading.
- Author
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Walsh SK, Skala MC, and Henak CR
- Subjects
- Animals, Antimetabolites pharmacology, Cartilage, Articular drug effects, Deoxyglucose pharmacology, Flavin-Adenine Dinucleotide, Glycolysis, NADP, Oxidative Phosphorylation, Rotenone pharmacology, Swine, Uncoupling Agents pharmacology, Cartilage, Articular diagnostic imaging, Cartilage, Articular metabolism, Optical Imaging methods, Osteoarthritis metabolism, Oxidation-Reduction, Weight-Bearing
- Abstract
Objective: Metabolic dysregulation has recently been identified as a key feature of osteoarthritis. Mechanical overloading has been postulated as a primary cause of this metabolic response. Current methods of real-time metabolic activity analysis in cartilage are limited and challenging. However, optical redox imaging leverages the autofluorescence of co-enzymes NAD(P)H and FAD to provide dye-free real-time analysis of metabolic activity. This technique has not yet been applied to cartilage. This study aimed to assess the effects of a compressive load on cartilage using optical redox imaging., Method: Cartilage samples were excised from porcine femoral condyles. To validate this imaging modality in cartilage, glycolysis was inhibited via 2-deoxy-D-glucose (2DG) and oxidative phosphorylation was inhibited by rotenone. Optical redox images were collected pre- and post-inhibition. To assess the effects of mechanical loading, samples were subjected to a compressive load and imaged for approximately 30 min. Load and strain parameters were determined using high-speed camera images in Matlab. A range of loading magnitudes and rates were applied across samples., Results: 2DG and rotenone demonstrated the expected inhibitory effects on fluorescence intensity in the channels corresponding to NAD(P)H and FAD, respectively. Mechanical loading induced an increase in NAD(P)H channel fluorescence which subsided by 30 min post-loading. Magnitude of loading parameters had mixed effects on metabolites., Conclusions: Optical redox imaging provides an opportunity to assess real-time metabolic activity in cartilage. This approach revealed a metabolic response to a single load and can be used to provide insight into the role of metabolism in mechanically-mediated cartilage degradation., (Copyright © 2019 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2019
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33. l-α-Lysophosphatidylinositol (LPI) aggravates myocardial ischemia/reperfusion injury via a GPR55/ROCK-dependent pathway.
- Author
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Robertson-Gray OJ, Walsh SK, Ryberg E, Jönsson-Rylander AC, Lipina C, and Wainwright CL
- Subjects
- Amides pharmacology, Animals, Disease Models, Animal, High-Throughput Screening Assays, Humans, Induced Pluripotent Stem Cells cytology, Induced Pluripotent Stem Cells drug effects, Induced Pluripotent Stem Cells metabolism, Male, Mice, Myocardial Reperfusion Injury metabolism, Phosphorylation drug effects, Pyridines pharmacology, Receptors, Cannabinoid genetics, Signal Transduction, p38 Mitogen-Activated Protein Kinases metabolism, Lysophospholipids adverse effects, Myocardial Reperfusion Injury chemically induced, Receptors, Cannabinoid metabolism, rho-Associated Kinases metabolism
- Abstract
The phospholipid l-α-lysophosphatidylinositol (LPI), an endogenous ligand for GPR55, is elevated in patients with acute coronary syndrome, and a GPR55 antagonist cannabidiol (CBD) reduces experimental ischemia/reperfusion (I/R) injury. While LPI activates multiple signaling pathways, little is known about which ones are important in cardiomyocytes. In this study we explored whether activation of the Rho kinase/ROCK/p38 MAPK pathway is responsible for LPI-induced extension of I/R injury. Using a high-throughput screening method (dynamic mass redistribution; DMR), mouse- and human-induced pluripotent stem cell (iPSC) cardiomyocytes exposed to LPI were shown to exhibit a rapid, sustained, and concentration-dependent (1 nmol L
-1 -30 μmol L-1 ) cellular response. Y-27632 (ROCK inhibitor; 10 & 50 μmol L-1 ) and CBD (1 μmol L-1 ) both abolished the DMR response to LPI (10 μmol L-1 ). In murine iPSC cardiomyocytes, LPI-induced ROCK and p38 MAPK phosphorylation, both of which were prevented by Y-27632 and CBD, but did not induce JNK activation or cleavage of caspase-3. In hearts isolated from wild type (WT) mice subjected to 30 minutes global I/R, LPI (10 μmol L-1 ) administered via the coronary circulation increased infarct size when applied prior to ischemia onset, but not when given at the time of reperfusion. The exacerbation of tissue injury by LPI was not seen in hearts from GPR55-/- mice or in the presence of Y-27632, confirming that injury is mediated via the GPR55/ROCK/p38 MAPK pathway. These findings suggest that raised levels of LPI in the vicinity of a developing infarct may worsen the outcome of AMI., Competing Interests: None.- Published
- 2019
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34. Acute dietary zinc deficiency in rats exacerbates myocardial ischaemia-reperfusion injury through depletion of glutathione.
- Author
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Skene K, Walsh SK, Okafor O, Godsman N, Barrows C, Meier P, Gordon MJ, Beattie JH, and Wainwright CL
- Subjects
- Animals, Heart drug effects, Male, Rats, Rats, Sprague-Dawley, Diet adverse effects, Glutathione metabolism, Myocardial Ischemia etiology, Myocardial Reperfusion Injury etiology, Zinc deficiency
- Abstract
Zn plays an important role in maintaining the anti-oxidant status within the heart and helps to counter the acute redox stress that occurs during myocardial ischaemia and reperfusion. Individuals with low Zn levels are at greater risk of developing an acute myocardial infarction; however, the impact of this on the extent of myocardial injury is unknown. The present study aimed to compare the effects of dietary Zn depletion with in vitro removal of Zn (N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN)) on the outcome of acute myocardial infarction and vascular function. Male Sprague-Dawley rats were fed either a Zn-adequate (35 mg Zn/kg diet) or Zn-deficient (<1 mg Zn/kg diet) diet for 2 weeks before heart isolation. Perfused hearts were subjected to a 30 min ischaemia/2 h reperfusion (I/R) protocol, during which time ventricular arrhythmias were recorded and after which infarct size was measured, along with markers of anti-oxidant status. In separate experiments, hearts were challenged with the Zn chelator TPEN (10 µm) before ischaemia onset. Both dietary and TPEN-induced Zn depletion significantly extended infarct size; dietary Zn depletion was associated with reduced total cardiac glutathione (GSH) levels, while TPEN decreased cardiac superoxide dismutase 1 levels. TPEN, but not dietary Zn depletion, also suppressed ventricular arrhythmias and depressed vascular responses to nitric oxide. These findings demonstrate that both modes of Zn depletion worsen the outcome from I/R but through different mechanisms. Dietary Zn deficiency, resulting in reduced cardiac GSH, is the most appropriate model for determining the role of endogenous Zn in I/R injury.
- Published
- 2019
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35. Developing a Novel Model to Improve Research and care for Cancer Survivors: a Feasibility Study.
- Author
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Rosenberg SM, Ligibel JA, Meyerhardt JA, Jacobsen ED, Garber JE, Nekhlyudov L, Bunnell CA, Nutting P, Sprunck-Harrild K, Walsh SK, and Partridge AH
- Subjects
- Adult, Aged, Clinical Trials as Topic, Feasibility Studies, Female, Humans, Middle Aged, Neoplasms therapy, Patient Care Planning, Pilot Projects, Surveys and Questionnaires, Survivorship, Attitude to Health, Biomedical Research, Cancer Survivors
- Abstract
Despite a growing number of clinical trials and supportive care programs for cancer survivors, recruitment of patients for these opportunities during the survivorship phase of care is challenging. We piloted a novel process to systematically educate patients about available research studies and supportive care programs as part of a survivorship care visit. Between 3/2015 and 8/2015, patients seen in the Adult Survivorship Program who had not previously received a treatment summary and survivorship care plan (TS/SCP) were provided with one accompanied by a list of survivorship research studies and care programs tailored to their diagnosis. Survivorship providers discussed the opportunities and recorded whether the patient was interested in relevant studies and placed referrals to study staff. Following the visit, we tracked study enrollment and surveyed patients about their experience. Fifty of 56 (89%) pilot participants completed the survey. Almost all (98%) reported that the TS/SCP visit and document helped with knowledge of research opportunities and supportive care interventions. Following receipt of the TS/SCP, 44% were interested in at least one study and in further follow-up with research staff. Of the 30 survivors eligible for at least one study, 6 (20%) have enrolled in at least one study to date. This pilot program demonstrates that the systematic sharing of available clinical studies and supportive care programming as part of a survivorship care plan visit is feasible and well received by cancer survivors and may facilitate and enhance accrual to clinical trials in the survivorship phase of care.
- Published
- 2019
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36. GPR55 deficiency is associated with increased adiposity and impaired insulin signaling in peripheral metabolic tissues.
- Author
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Lipina C, Walsh SK, Mitchell SE, Speakman JR, Wainwright CL, and Hundal HS
- Subjects
- 3T3-L1 Cells, Adipose Tissue cytology, Animals, Cell Line, Tumor, Energy Metabolism, Humans, Liver cytology, Mice, Mice, Knockout, Muscle, Skeletal cytology, Phosphorylation, Proto-Oncogene Proteins c-akt metabolism, Rats, Receptors, Cannabinoid genetics, Adipose Tissue metabolism, Adiposity genetics, Insulin metabolism, Liver metabolism, Muscle, Skeletal metabolism, Receptors, Cannabinoid physiology, Signal Transduction
- Abstract
Emerging evidence indicates that G-protein coupled receptor 55 (GPR55), a nonclassic receptor of the endocannabinoid system that is activated by L-α-lysophosphatidylinositol and various cannabinoid ligands, may regulate endocrine function and energy metabolism. We examined how GPR55 deficiency and modulation affects insulin signaling in skeletal muscle, adipose tissue, and liver alongside expression analysis of proteins implicated in insulin action and energy metabolism. We show that GPR55-null mice display decreased insulin sensitivity in these tissues, as evidenced by reduced phosphorylation of PKB/Akt and its downstream targets, concomitant with increased adiposity and reduced physical activity relative to wild-type counterparts. Impaired tissue insulin sensitivity coincided with reduced insulin receptor substrate-1 abundance in skeletal muscle, whereas in liver and epididymal fat it was associated with increased expression of the 3-phosphoinoistide lipid phosphatase, phosphatase and tensin homolog. In contrast, GPR55 activation enhanced insulin signaling in cultured skeletal muscle cells, adipocytes, and hepatocytes; this response was negated by receptor antagonists and GPR55 gene silencing in L6 myotubes. Sustained GPR55 antagonism in 3T3-L1 adipocytes enhanced expression of proteins implicated in lipogenesis and promoted triglyceride accumulation. Our findings identify GPR55 as a positive regulator of insulin action and adipogenesis and as a potential therapeutic target for countering obesity-induced metabolic dysfunction and insulin resistance.-Lipina, C., Walsh, S. K., Mitchell, S. E., Speakman, J. R., Wainwright, C. L., Hundal, H. S. GPR55 deficiency is associated with increased adiposity and impaired insulin signaling in peripheral metabolic tissues.
- Published
- 2019
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37. Feasibility and Acceptability of a Web Site to Promote Survivorship Care in Survivors of Hodgkin Disease.
- Author
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Underhill ML, Hong F, Jones T, Sprunck-Harrild K, Walsh SK, Boyajian R, Berry DL, and Partridge A
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Follow-Up Studies, Hodgkin Disease diagnosis, Hodgkin Disease therapy, Humans, Male, Middle Aged, Neoplasm Staging, Cancer Survivors, Health Promotion methods, Hodgkin Disease epidemiology, Survivorship, Web Browser
- Abstract
Purpose: Evaluate rates of enrollment, completion, and patient-reported acceptability of an educational survivorship-care Web site for survivors of Hodgkin disease (HD)., Patients and Methods: The study was a mixed-method evaluation design. Eligible participants were adults who had completed treatment of a primary diagnosis of HD ≥ 2 years before enrollment. Patients were recruited through postal mail and telephone and were asked to review a Web site, complete an adapted version of the Acceptability E-scale (total score of 24 or greater indicates acceptability), and respond to a structured telephone or e-mail interview to discuss experiences with the Web site., Results: Of 259 potentially eligible participants identified by medical record review, 124 survivors had confirmed contact with study staff and were invited to participate; 63 people (50.8%; 90% CI, 43% to 59%) enrolled; 37 participants (58.7%) were men. The median age at time of enrollment was 51.0 years (range, 29.3 to 80.0 years), and the median time since completion of treatment of HD was 14.9 years (range, 3 to 38.75 years). Overall, 82.5% of those enrolled viewed all Web site content. Forty-eight participants completed the acceptability survey, which resulted in a mean acceptability score of 26.5 (standard deviation, 3.5). The majority of enrollees (67%) completed a follow-up interview., Conclusion: Overall, HD survivor participants viewed the content and reviewed it favorably. A Web-based intervention is a promising way to provide survivors of HD with information about how to manage the long-term and late effects from cancer and treatment, and provide trusted survivorship resources.
- Published
- 2017
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38. Oncofertility: Fertile Ground for Conflict Between Patient Autonomy and Medical Values.
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Walsh SK, Ginsburg ES, Lehmann LS, and Partridge AH
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- Adult, Breast Neoplasms, Cryopreservation methods, Embryo Transfer ethics, Female, Fertility Preservation methods, Humans, Oocyte Retrieval ethics, Oocyte Retrieval methods, Oocytes physiology, Pregnancy, Young Adult, Fertility Preservation ethics, Oocyte Retrieval adverse effects, Personal Autonomy, Pregnancy Complications, Neoplastic
- Abstract
Oncofertility is a unique, multidisciplinary field that serves to bridge the gap between available fertility resources and the special reproductive needs of cancer patients. Oncofertility is a growing field due to the increasing number of survivors, development of new oncologic therapies, extension of duration of therapies, and development and refinement of reproductive therapies. While the technologies and demand for services expand, clinicians need to be appropriately prepared for dealing with various clinical scenarios that may require ethical deliberation. Three real cases are presented in which the patient wishes to pursue reproductive assistance, but her decision is met with hesitance or uncertainty by her care team. Discussion of these clinical scenarios highlights ethical implications of oncofertility practice and serves to highlight the need for the establishment of multidisciplinary care teams and guidelines to support both clinicians and patients., Implications for Practice: The growing field of oncofertility is ripe for conflict between patient autonomy and medical values due to the nature of cancer and associated threat on an individual's health and survival, as well as the personal significance of childbearing. Cases are presented and ethical implications are discussed to further explore the inherent difficulties in oncofertility practice and guide clinicians in similar situations. Developing guidelines and establishing multidisciplinary teams to facilitate oncofertility discussions and care, as well as training of clinical team members, may improve patient safety, well-being, and satisfaction within the context of fertility decision making, care, and outcomes., Competing Interests: Disclosures of potential conflicts of interest may be found at the end of this article., (© AlphaMed Press 2017.)
- Published
- 2017
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39. What to do when we can't bank on seeds: What botanic gardens can learn from the zoo community about conserving plants in living collections.
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Fant JB, Havens K, Kramer AT, Walsh SK, Callicrate T, Lacy RC, Maunder M, Meyer AH, and Smith PP
- Subjects
- Conservation of Natural Resources, Plants, Seed Bank
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- 2016
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40. Development of a cell line from the American eel brain expressing endothelial cell properties.
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Bloch SR, Vo NT, Walsh SK, Chen C, Lee LE, Hodson PV, and Bols NC
- Subjects
- Animals, Capillaries metabolism, Cell Proliferation, Cell Shape, Cellular Senescence, Chromosomes metabolism, Endothelial Cells metabolism, Immunohistochemistry, Staining and Labeling, Temperature, Tight Junction Proteins metabolism, Vimentin metabolism, beta-Galactosidase metabolism, Brain cytology, Cell Line cytology, Eels metabolism, Endothelial Cells cytology
- Abstract
A cell line (eelB) was developed from the outgrowth of adherent cells from brain explants of the American eel, Anguilla rostrata (Lesueur). EelB cells have been grown routinely in L-15 with 10% fetal bovine serum (FBS), undergone over 100 passages, and cryopreserved successfully. The cells from late-passage cultures (>45) were polygonal, formed capillary-like structures (CLS) on Matrigel, and stained immunocytochemically for von Willebrand factor (vWF) and for three tight junction proteins, zonula occludens-1 (ZO-1), claudin 3, and claudin 5. These results suggest that eelB is an endothelial cell line, one of the few from fish and the first from the brain. Despite this, eelB did not respond to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with the induction of CYP1A protein. The cells from early-passage cultures (<20) had more varied shapes and did not form CLS on Matrigel. Only cells from early-passage cultures formed in suspension three-dimensional aggregates that had some cells expressing alkaline phosphatase and nestin. These cells are thought to be neural stem cells and the aggregates neurospheres. The emergence of endothelial-like cells upon the continued subcultivation of cells from early-passage cultures that had neural stem cells has been described previously for mammals, but this is a first for teleosts. Remarkably, cells from all passage levels were stained strongly for senescence-associated β-galactosidase (SA β-Gal) activity.
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- 2016
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41. Pharmacological profiling of the hemodynamic effects of cannabinoid ligands: a combined in vitro and in vivo approach.
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Walsh SK, Hepburn CY, Keown O, Åstrand A, Lindblom A, Ryberg E, Hjorth S, Leslie SJ, Greasley PJ, and Wainwright CL
- Abstract
The receptors mediating the hemodynamic responses to cannabinoids are not clearly defined due to the multifarious pharmacology of many commonly used cannabinoid ligands. While both CB1 and TRPV1 receptors are implicated, G protein-coupled receptor 55 (GPR55) may also mediate some of the hemodynamic effects of several atypical cannabinoid ligands. The present studies attempted to unravel the pharmacology underlying the in vivo hemodynamic responses to ACEA (CB1 agonist), O-1602 (GPR55 agonist), AM251 (CB1 antagonist), and cannabidiol (CBD; GPR55 antagonist). Agonist and antagonist profiles of each ligand were determined by ligand-induced GTPγS binding in membrane preparations expressing rat and mouse CB1 and GPR55 receptors. Blood pressure responses to ACEA and O-1602 were recorded in anesthetized and conscious mice (wild type, CB1 (-/-) and GPR55(-/-)) and rats in the absence and presence of AM251 and CBD. ACEA demonstrated GTPγS activation at both receptors, while O-1602 only activated GPR55. AM251 exhibited antagonist activity at CB1 and agonist activity at GPR55, while CBD demonstrated selective antagonist activity at GPR55. The depressor response to ACEA was blocked by AM251 and attenuated by CBD, while O-1602 did not induce a depressor response. AM251 caused a depressor response that was absent in GPR55(-/-) mice but enhanced by CBD, while CBD caused a small vasodepressor response that persisted in GPR55(-/-) mice. Our findings show that assessment of the pharmacological profile of receptor activation by cannabinoid ligands in in vitro studies alongside in vivo functional studies is essential to understand the role of cannabinoids in hemodynamic control.
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- 2015
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42. GPR55 deletion in mice leads to age-related ventricular dysfunction and impaired adrenoceptor-mediated inotropic responses.
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Walsh SK, Hector EE, Andréasson AC, Jönsson-Rylander AC, and Wainwright CL
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- Animals, Collagen metabolism, Female, Hemodynamics, Male, Mice, Receptors, Cannabinoid metabolism, Ventricular Function, Left, Aging pathology, Gene Deletion, Myocardial Contraction, Receptors, Adrenergic metabolism, Receptors, Cannabinoid deficiency, Ventricular Dysfunction physiopathology
- Abstract
G protein coupled receptor 55 (GPR55) is expressed throughout the body, and although its exact physiological function is unknown, studies have suggested a role in the cardiovascular system. In particular, GPR55 has been proposed as mediating the haemodynamic effects of a number of atypical cannabinoid ligands; however this data is conflicting. Thus, given the incongruous nature of our understanding of the GPR55 receptor and the relative paucity of literature regarding its role in cardiovascular physiology, this study was carried out to examine the influence of GPR55 on cardiac function. Cardiac function was assessed via pressure volume loop analysis, and cardiac morphology/composition assessed via histological staining, in both wild-type (WT) and GPR55 knockout (GPR55(-/-)) mice. Pressure volume loop analysis revealed that basal cardiac function was similar in young WT and GPR55(-/-) mice. In contrast, mature GPR55(-/-) mice were characterised by both significant ventricular remodelling (reduced left ventricular wall thickness and increased collagen deposition) and systolic dysfunction when compared to age-matched WT mice. In particular, the load-dependent parameter, ejection fraction, and the load-independent indices, end-systolic pressure-volume relationship (ESPVR) and Emax, were all significantly (P<0.05) attenuated in mature GPR55(-/-) mice. Furthermore, GPR55(-/-) mice at all ages were characterised by a reduced contractile reserve. Our findings demonstrate that mice deficient in GPR55 exhibit maladaptive adrenergic signalling, as evidenced by the reduced contractile reserve. Furthermore, with age these mice are characterised by both significant adverse ventricular remodelling and systolic dysfunction. Taken together, this may suggest a role for GPR55 in the control of adrenergic signalling in the heart and potentially a role for this receptor in the pathogenesis of heart failure.
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- 2014
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43. Diabetic Schwann cells suffer from nerve growth factor and neurotrophin-3 underproduction and poor associability with axons.
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Dey I, Midha N, Singh G, Forsyth A, Walsh SK, Singh B, Kumar R, Toth C, and Midha R
- Subjects
- Animals, Axons drug effects, Cell Proliferation drug effects, Hyperglycemia metabolism, Insulin metabolism, Insulin pharmacology, Mice, Nerve Regeneration drug effects, Nerve Regeneration physiology, Schwann Cells drug effects, Sciatic Nerve drug effects, Sciatic Nerve metabolism, Axons metabolism, Diabetes Mellitus, Experimental metabolism, Diabetes Mellitus, Type 1 metabolism, Diabetes Mellitus, Type 2 metabolism, Nerve Growth Factor metabolism, Neurotrophin 3 metabolism, Schwann Cells metabolism
- Abstract
Schwann cells (SCs) are integral to peripheral nerve biology, contributing to saltatory conduction along axons, nerve and axon development, and axonal regeneration. SCs also provide a microenvironment favoring neural regeneration partially due to production of several neurotrophic factors. Dysfunction of SCs may also play an important role in the pathogenesis of peripheral nerve diseases such as diabetic peripheral neuropathy where hyperglycemia is often considered pathogenic. In order to study the impact of diabetes mellitus (DM) upon the regenerative capacity of adult SCs, we investigated the differential production of the neurotrophic factors nerve growth factor (NGF) and neurotrophin-3 (NT3) by SCs harvested from the sciatic nerves of murine models of type 1 DM (streptozotocin treated C57BL/6J mice) and type 2 DM (LepR(-/-) or db/db mice) or non-diabetic cohorts. In vitro, SCs from diabetic and control mice were maintained under similar hyperglycemic and euglycemic conditions respectively. Mature SCs from diabetic mice produced lower levels of NGF and NT3 under hyperglycemic conditions when compared to SCs in euglycemia. In addition, SCs from both DM and non-DM mice appear to be incapable of insulin production, but responded to exogenous insulin with greater proliferation and heightened myelination potentiation. Moreover, SCs from diabetic animals showed poorer association with co-cultured axons. Hyperglycemia had significant impact upon SCs, potentially contributing to the pathogenesis of diabetic peripheral neuropathy., (Copyright © 2013 Wiley Periodicals, Inc.)
- Published
- 2013
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44. PPAR-γ -- a possible drug target for complicated pregnancies.
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McCarthy FP, Delany AC, Kenny LC, and Walsh SK
- Subjects
- Animals, Female, Humans, Pregnancy Complications prevention & control, PPAR gamma metabolism, Pregnancy metabolism, Pregnancy Complications metabolism
- Abstract
Peroxisome proliferator activated receptors (PPARs) are ligand-activated transcription factors expressed in trophoblasts, which regulate both cell differentiation and proliferation. In recent years, evidence has linked PPARs to playing an integral role in pregnancy; specifically, PPAR-β and PPAR-γ have been shown to play an integral role in placentation, with PPAR-γ additionally serving to regulate trophoblast differentiation. Recent evidence has shown that PPAR-γ expression is altered in many complications of pregnancy such as intrauterine growth restriction (IUGR), preterm birth, pre-clampsia and gestational diabetes. Thus, at present, accumulating evidence from the literature suggests both a pivotal role for PPAR-γ in the progression of a healthy pregnancy and the possibility that PPAR-γ may act as a therapeutic target in complicated pregnancies. This review aims to provide a succinct and comprehensive assessment of the role of PPAR-γ in normal pregnancy and pregnancy complications, and finally its potential as a therapeutic target in the treatment and/or prevention of adverse pregnancy outcomes., (© 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.)
- Published
- 2013
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45. Administration of the PARP inhibitor Pj34 ameliorates the impaired vascular function associated with eNOS(-/-) mice.
- Author
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English FA, McCarthy FP, Andersson IJ, Stanley JL, Davidge ST, Baker PN, Walsh SK, and Kenny LC
- Subjects
- Animals, Enzyme Inhibitors pharmacology, Female, Fetal Growth Retardation physiopathology, Gestational Age, Mice, Mice, Inbred C57BL, Mice, Knockout, Nitric Oxide Synthase Type III genetics, Nitric Oxide Synthase Type III physiology, Pre-Eclampsia physiopathology, Pregnancy, Uterine Artery drug effects, Nitric Oxide Synthase Type III deficiency, Phenanthrenes pharmacology, Poly(ADP-ribose) Polymerase Inhibitors, Pregnancy Complications physiopathology, Uterine Artery physiopathology
- Abstract
A low-resistance/high-flow uteroplacental circulation is integral to a healthy pregnancy. Impaired flow in the uterine circulation is associated with intrauterine growth restriction (IUGR) and preeclampsia (PE). Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which has been associated with oxidative stress-induced vascular dysfunction. Using the endothelial nitric oxide synthase (eNOS(-/ -)) knockout mouse model, which features vascular dysfunction and IUGR, we tested the hypothesis that administration of a PARP inhibitor may ameliorate the vascular dysfunction associated with the eNOS(-/-) model. eNOS(-/-) animals were characterized by impaired uterine artery function when compared to controls. Administration of the PARP inhibitor PJ34 prevented this dysfunction. Gestational day (GD) 17.5 eNOS(-/-) mice did not exhibit altered systolic blood pressure when compared to control mice. However, treatment of eNOS(-/-) mice with PJ34 significantly reduced systolic blood pressure when compared to vehicle-treated eNOS(-/-). Administration of a PARP inhibitor protects uterine artery function in the face of eNOS(-/-) deficiency.
- Published
- 2012
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46. Fate of stem cell transplants in peripheral nerves.
- Author
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Walsh SK, Kumar R, Grochmal JK, Kemp SW, Forden J, and Midha R
- Subjects
- Animals, Apoptosis drug effects, Axons drug effects, Axons metabolism, Cell Differentiation drug effects, Cell Proliferation drug effects, Cell Survival drug effects, Mice, Myelin Sheath drug effects, Myelin Sheath metabolism, Neuregulin-1 pharmacology, Peripheral Nerve Injuries pathology, Peripheral Nerve Injuries therapy, Peripheral Nerves drug effects, Phenotype, Rats, Skin cytology, Skin drug effects, Stem Cells drug effects, Cell Lineage drug effects, Peripheral Nerves pathology, Stem Cell Transplantation, Stem Cells cytology
- Abstract
While damaged peripheral nerves demonstrate some potential to regenerate, complete functional recovery remains infrequent, owing to a functional loss of supportive Schwann cells distal to the injury. An emerging solution to improve upon this intrinsic regenerative capacity is to supplement injured nerves with stem cells derived from various tissues. While many of these strategies have proven successful in animal models, few studies have examined the behavior of transplanted stem cells in vivo, including whether they survive and differentiate. In previous work, we demonstrated that cells derived from neonatal rodent dermis (skin-derived precursor cells, or SKPs) could improve regenerative parameters when transplanted distal to both acute and chronic nerve injuries in Lewis rats. The aim of this work was to track the fate of these cells in various nerve injury paradigms and determine the response of these cells to a known glial growth factor. Here, we report that SKPs survive, respond to local cues, differentiate into myelinating Schwann cells, and avoid complete clearance by the host's immune defenses for a minimum of 10weeks. Moreover, the ultimate fate of SKPs in vivo depends on the nerve environment into which they are injected and can be modified by inclusion of heregulin-1β., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2012
- Full Text
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47. Evidence implicating peroxisome proliferator-activated receptor-γ in the pathogenesis of preeclampsia.
- Author
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McCarthy FP, Drewlo S, English FA, Kingdom J, Johns EJ, Kenny LC, and Walsh SK
- Subjects
- Animals, Biopsy, Needle, Disease Models, Animal, Female, Immunohistochemistry, PPAR gamma antagonists & inhibitors, Platelet Aggregation, Pre-Eclampsia enzymology, Pre-Eclampsia pathology, Pregnancy, RNA, Messenger metabolism, Random Allocation, Rats, Rats, Sprague-Dawley, Real-Time Polymerase Chain Reaction, Reference Values, Statistics, Nonparametric, Urinalysis, Vascular Endothelial Growth Factor A metabolism, Vascular Endothelial Growth Factor Receptor-1 metabolism, PPAR gamma metabolism, Pre-Eclampsia physiopathology, Pregnancy, Animal, Vascular Endothelial Growth Factor A drug effects
- Abstract
Preeclampsia, a major cause of maternal and perinatal mortality and morbidity, is thought to be attributed, in part, to impaired trophoblast invasion. Peroxisome proliferator-activated receptors are ligand-activated transcription factors expressed in trophoblasts, which regulate the expression of a number of genes involved in cell differentiation and proliferation. We investigated the effect of the administration of a peroxisome proliferator-activated receptor-γ antagonist during uncomplicated pregnancy in rats. Using an intraperitoneal miniosmotic pump, healthy pregnant rats were administered either vehicle or the peroxisome proliferator-activated receptor-γ-specific antagonist, T0070907 (1 mg/kg per day from gestational days 11-15). Rats treated with T0070907 developed key features of preeclampsia, including elevated mean arterial blood pressure, proteinuria, endothelial dysfunction, reduced pup weight, and increased platelet aggregation. T0070907-treated rats had reduced plasma vascular endothelial growth factor and increased plasma soluble fms-like tyrosine kinase 1. Furthermore, increases in total placental soluble fms-like tyrosine kinase 1 mRNA and fms-like tyrosine kinase 1 protein were also demonstrated, suggesting the placenta as the main contributor to the increased circulating levels of soluble fms-like tyrosine kinase 1. The labyrinthine trophoblast in the placentas of T0070907-treated rats were less differentiated, had increased cellular proliferation, and were strongly immunopositive for CD-31 staining, indicating adaptive angiogenesis. The present study suggests that peroxisome proliferator-activated receptor-γ may play a pivotal role in the progression of a healthy pregnancy and may critically regulate the risk of preeclampsia. These findings have important implications regarding the underlying etiology of preeclampsia and potential therapeutic targets.
- Published
- 2011
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48. Metabolic profiling uncovers a phenotypic signature of small for gestational age in early pregnancy.
- Author
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Horgan RP, Broadhurst DI, Walsh SK, Dunn WB, Brown M, Roberts CT, North RA, McCowan LM, Kell DB, Baker PN, and Kenny LC
- Subjects
- Animals, Chromatography, Liquid, Female, Fetal Growth Retardation, Humans, Infant, Newborn, Mass Spectrometry, Models, Animal, Multivariate Analysis, Pregnancy, ROC Curve, Rats, Rats, Sprague-Dawley, Infant, Small for Gestational Age, Pregnancy Trimester, First metabolism
- Abstract
Being born small for gestational age (SGA) confers increased risks of perinatal morbidity and mortality and increases the risk of cardiovascular complications and diabetes in later life. Accumulating evidence suggests that the etiology of SGA is usually associated with poor placental vascular development in early pregnancy. We examined metabolomic profiles using ultra performance liquid chromatography-mass spectrometry (UPLC-MS) in three independent studies: (a) venous cord plasma from normal and SGA babies, (b) plasma from a rat model of placental insufficiency and controls, and (c) early pregnancy peripheral plasma samples from women who subsequently delivered a SGA baby and controls. Multivariate analysis by cross-validated Partial Least Squares Discriminant Analysis (PLS-DA) of all 3 studies showed a comprehensive and similar disruption of plasma metabolism. A multivariate predictive model combining 19 metabolites produced by a Genetic Algorithm-based search program gave an Odds Ratio for developing SGA of 44, with an area under the Receiver Operator Characteristic curve of 0.9. Sphingolipids, phospholipids, carnitines, and fatty acids were among this panel of metabolites. The finding of a consistent discriminatory metabolite signature in early pregnancy plasma preceding the onset of SGA offers insight into disease pathogenesis and offers the promise of a robust presymptomatic screening test.
- Published
- 2011
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- View/download PDF
49. Peroxisome proliferator-activated receptor-γ as a potential therapeutic target in the treatment of preeclampsia.
- Author
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McCarthy FP, Drewlo S, Kingdom J, Johns EJ, Walsh SK, and Kenny LC
- Subjects
- Animals, Female, PPAR gamma agonists, Pre-Eclampsia physiopathology, Pregnancy, Rats, Rats, Sprague-Dawley, Rosiglitazone, Blood Pressure drug effects, Metalloporphyrins pharmacology, PPAR gamma metabolism, Pre-Eclampsia metabolism, Protoporphyrins pharmacology, Thiazolidinediones pharmacology
- Abstract
Preeclampsia is a multisystemic disorder of pregnancy characterized by hypertension, proteinuria, and maternal endothelial dysfunction. It is a major cause of maternal and perinatal morbidity and mortality and is thought to be attributable, in part, to inadequate trophoblast invasion. Peroxisome proliferator-activated receptor-γ (PPAR-γ) is a ligand-activated transcription factor expressed in trophoblasts, and the vasculature of which activation has been shown to improve endothelium-dependent vasodilatation in hypertensive conditions. We investigated the effects of the administration of a PPAR-γ agonist using the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. The selective PPAR-γ agonist, rosiglitazone, was administered to pregnant rats that had undergone RUPP surgery. To investigate whether any observed beneficial effects of PPAR-γ activation were mediated by the antioxidant enzyme, heme oxygenase 1, rosiglitazone was administered in combination with the heme oxygenase 1 inhibitor tin-protoporphyrin IX. RUPP rats were characterized by hypertension, endothelial dysfunction, and elevated microalbumin:creatinine ratios. Rosiglitazone administration ameliorated hypertension, improved vascular function, and reduced the elevated microalbumin:creatinine ratio in RUPP rats. With the exception of microalbumin:creatinine ratio, these beneficial effects were abrogated in the presence of the heme oxygenase 1 inhibitor. Administration of a PPAR-γ agonist prevented the development of several of the pathophysiological characteristics associated with the RUPP model of preeclampsia, via a heme oxygenase 1-dependent pathway. The findings from this study provide further insight into the underlying etiology of preeclampsia and a potential therapeutic target for the treatment of preeclampsia.
- Published
- 2011
- Full Text
- View/download PDF
50. Animal models of preeclampsia; uses and limitations.
- Author
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McCarthy FP, Kingdom JC, Kenny LC, and Walsh SK
- Subjects
- Animals, Female, Humans, Pregnancy, Disease Models, Animal, Pre-Eclampsia
- Abstract
Preeclampsia remains a leading cause of maternal and fetal morbidity and mortality and has an unknown etiology. The limited progress made regarding new treatments to reduce the incidence and severity of preeclampsia has been attributed to the difficulties faced in the development of suitable animal models for the mechanistic research of this disease. In addition, animal models need hypotheses on which to be based and the slow development of testable hypotheses has also contributed to this poor progress. The past decade has seen significant advances in our understanding of preeclampsia and the development of viable reproducible animal models has contributed significantly to these advances. Although many of these models have features of preeclampsia, they are still poor overall models of the human disease and limited due to lack of reproducibility and because they do not include the complete spectrum of pathophysiological changes associated with preeclampsia. This review aims to provide a succinct and comprehensive assessment of current animal models of preeclampsia, their uses and limitations with particular attention paid to the best validated and most comprehensive models, in addition to those models which have been utilized to investigate potential therapeutic interventions for the treatment or prevention of preeclampsia., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
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