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This article discusses the limitations of using rodent models in heart transplantation research and highlights the shift towards using human specimens for discovery research. The authors focus on a study that uses single-nucleus RNA sequencing to investigate the cellular landscape of transplanted pediatric hearts. The study identifies important candidate mediators of heart transplant failure, such as graft-infiltrating macrophages and natural killer cells. The authors also explore the dynamics of immune cells within the failing transplanted heart and highlight the potential therapeutic targets that could be investigated further. However, the study has limitations due to the small sample size and the difficulty in obtaining healthy heart transplant tissue. Overall, the article emphasizes the potential of single-cell sequencing and other molecular pathology techniques in advancing our understanding of heart transplantation. [Extracted from the article]

Background: Ex vivo heart perfusion (EVHP) of donation after circulatory death (DCD) hearts has become an effective strategy in adults; however, the small circulating volume in pediatrics poses the challenge of a low-hemoglobin (Hb) perfusate. We aimed to determine the impact of perfusate Hb levels during EVHP on DCD hearts using a juvenile porcine model., Methods: Sixteen DCD piglet hearts (11-14 kg) were reperfused for 4 h in unloaded mode followed by working mode. Metabolism, cardiac function, and cell damage were compared between the low-Hb (Hb, 5.0-5.9 g/dL; n = 8) and control (Hb, 7.5-8.4 g/dL; n = 8) groups. Between-group differences were evaluated using 2-sample t -tests or Fisher's Exact tests., Results: During unloaded mode, the low-Hb group showed lower myocardial oxygen consumption ( P  < 0.001), a higher arterial lactate level ( P  = 0.001), and worse systolic ventricular function ( P  < 0.001). During working mode, the low-Hb group had a lower cardiac output (mean, 71% versus 106% of normal cardiac output, P  = 0.010) and a higher arterial lactate level ( P  = 0.031). Adjusted cardiac troponin-I ( P  = 0.112) did not differ between the groups. Morphological myocyte injury in the left ventricle was more severe in the low-Hb group ( P  = 0.028)., Conclusions: Low-Hb perfusate with inadequate oxygen delivery induced anaerobic metabolism, resulting in suboptimal DCD heart recovery and declined cardiac function. Arranging an optimal perfusate is crucial to organ protection, and further endeavors to refine the priming volume of EVHP or the transfusion strategy are required., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Although artificial and non-nutritive sweeteners are widely used and generally recognized as safe by the US and European Union regulatory agencies, there have been no clinical trials to assess either long-term cardiovascular disease risks or short-term cardiovascular disease-relevant phenotypes. Recent studies report that fasting plasma levels of erythritol, a commonly used sweetener, are clinically associated with heightened incident cardiovascular disease risks and enhance thrombosis potential in vitro and in animal models. Effects of dietary erythritol on thrombosis phenotypes in humans have not been examined., Methods: Using a prospective interventional study design, we tested the impact of erythritol or glucose consumption on multiple indices of stimulus-dependent platelet responsiveness in healthy volunteers (n=10 per group). Erythritol plasma levels were quantified with liquid chromatography tandem mass spectrometry. Platelet function at baseline and following erythritol or glucose ingestion was assessed via both aggregometry and analysis of granule markers released., Results: Dietary erythritol (30 g), but not glucose (30 g), lead to a >1000-fold increase in erythritol plasma concentration (6480 [5930-7300] versus 3.75 [3.35-3.87] μmol/L; P <0.0001) and exhibited acute enhancement of stimulus-dependent aggregation responses in all subjects, agonists, and doses examined. Erythritol ingestion also enhanced stimulus-dependent release of the platelet dense granule marker serotonin ( P <0.0001 for TRAP6 [thrombin activator peptide 6] and P =0.004 for ADP) and the platelet α-granule marker CXCL4 (C-X-C motif ligand-4; P <0.0001 for TRAP6 and P =0.06 for ADP). In contrast, glucose ingestion triggered no significant increases in stimulus-dependent release of either serotonin or CXCL4., Conclusions: Ingestion of a typical quantity of the non-nutritive sweetener erythritol, but not glucose, enhances platelet reactivity in healthy volunteers, raising concerns that erythritol consumption may enhance thrombosis potential. Combined with recent large-scale clinical observational studies and mechanistic cell-based and animal model studies, the present findings suggest that discussion of whether erythritol should be reevaluated as a food additive with the Generally Recognized as Safe designation is warranted., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04731363., Competing Interests: S.L. Hazen and Z. Wang report being named as coinventors on pending and issued patents held by the Cleveland Clinic relating to cardiovascular diagnostics and therapeutics, all unrelated to the subject and contents of this article. S.L. Hazen and Z. Wang also report having received royalty payments for inventions or discoveries related to cardiovascular diagnostics or therapeutics from Procter & Gamble and Cleveland HeartLab, Inc, a fully owned subsidiary of Quest Diagnostics. S.L. Hazen is a paid consultant at Zehna Therapeutics, has received research funds from Zehna Therapeutics, and is eligible to receive royalty payments for inventions or discoveries related to cardiovascular diagnostics and therapeutics from Zehna Therapeutics. W.H.W. Tang reports being a consult at Sequana Medical A.G., Cardiol Therapeutics, Zehna Therapeutics, Genomics plc, Boston Scientific, WhiteSwell, Bristol Myers Squibb, Intellia Therapeutics, Alexion Pharmaceuticals, Alleviant Medical, CardiaTec Biosciences, Salubris Biotherapeutics, BioCardia, and has received honoraria from American Board of Internal Medicine, Belvoir Media Group, and Springer Nature. The other authors report no conflicts.

Background: The unstable recipient conditions after fat grafting remain an obstacle for tissue volumization. The interaction between fat grafts and recipient sites is not fully understood. The authors hypothesize that recipient-derived adipocytes undergo dedifferentiation and migrate into fat grafts in tissue regeneration., Methods: To observe the participation from recipient fat pad, the authors established a recipient adipocyte-tracing model where 0.2 mL of inguinal fat from 10 8-week-old C57BL/6 mice was grafted to 10 tamoxifen-treated AdipoqCre;mT/mG mice. Next, to evaluate the impact of physical force on recipient fat and fat graft, a murine internal expansion model was established by implanting a 1-mL internal expander on the inguinal fat pad of the lineage tracing mice that received fat graft from C57BL/6 mice. Transplanted adipose tissue was collected and analyzed by immunostaining of green fluorescent protein (GFP), tdTomato, perilipin, and CD31., Results: In the observing model, immunostaining revealed that both GFP+ and tdTomato + cells from the recipient fat pad presented in fat grafts. Among the GFP + cells, most of them were perilipin + adipocytes and other perilipin - cells co-expressed octamer-binding transcription factor 4, indicating dedifferentiated adipocytes. In the internal expansion model, internal expansion increased GFP + cells in fat graft. Both octamer-binding transcription factor 4-positive/GFP + (0.23 ± 0.01 versus 0.12 ± 0.04) and perilipin + /GFP + (0.17 ± 0.02 versus 0.06 ± 0.01) cells were increased in the expanded group, compared with control., Conclusions: Host-derived adipocytes participate in fat graft regeneration through migration and dedifferentiation, which could be enhanced by internal expansion to increase fat graft retention rate. Further study using a larger animal model is needed, because this is a murine study., Clinical Relevance Statement: Surgeons are encouraged to use physical expansion preconditioning of the recipient site. Subsequent and multiple fat grafting into the fat layer is encouraged to obtain satisfactory soft-tissue volumization., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Competing Interests: None.

Pulmonary hypertension is a rare, incurable, and progressive disease. Although there is increasing evidence that immune disorders, particularly those associated with connective tissue diseases, are a strong predisposing factor in the development of pulmonary arterial hypertension (PAH), there is currently a lack of knowledge about the detailed molecular mechanisms responsible for this phenomenon. Exploring this topic is crucial because patients with an immune disorder combined with PAH have a worse prognosis and higher mortality compared with patients with other PAH subtypes. Moreover, data recorded worldwide show that the prevalence of PAH in women is 2× to even 4× higher than in men, and the ratio of PAH associated with autoimmune diseases is even higher (9:1). Sexual dimorphism in the pathogenesis of cardiovascular disease was explained for many years by the action of female sex hormones. However, there are increasing reports of interactions between sex hormones and sex chromosomes, and differences in the pathogenesis of cardiovascular disease may be controlled not only by sex hormones but also by sex chromosome pathways that are not dependent on the gonads. This review discusses the role of estrogen and genetic factors including the role of genes located on the X chromosome, as well as the potential protective role of the Y chromosome in sexual dimorphism, which is prominent in the occurrence of PAH associated with autoimmune diseases. Moreover, an overview of animal models that could potentially play a role in further investigating the aforementioned link was also reviewed.

Background: During pulsed field ablation (PFA), relationships between ablation parameters (contact force [CF], number of burst pulses, impedance decrease, and electrode temperature) and lesion size in beating hearts have not been well validated., Methods: A 7.5F-catheter with a 3.5-mm ablation electrode and CF sensor (ThermoCool SmartTouch SF-Dual-Energy, Biosense Webster, Inc, Irwindale, CA) was connected to a PFA system (TRUPULSE2, Biosense Webster, Inc). In 11 closed-chest swine, biphasic PFA current was delivered between the ablation electrode and the skin patch at 219 sites in left ventricle and right ventricle using 12, 18, and 24 burst pulses with 4 different levels of CF: (1) low (n=57; CF, 4-15 g ; median, 10 g ); (2) moderate (n=60; CF, 16-30 g ; median, 22.5 g ); (3) high (n=68; CF, 32-65 g ; median, 40 g ); and (4) no electrode contact (n=34), 2 mm away from the endocardium. Swine were euthanized 2 hours after ablation, and lesion size was measured using triphenyl tetrazolium chloride staining., Results: All PFA lesions with electrode-myocardium contact were well demarcated with triphenyl tetrazolium chloride staining, demonstrating (1) pale central zone (contraction band necrosis with minimal coagulation necrosis), (2) dark brown zone (contraction band necrosis with hemorrhage), and (3) hyperstained red zone by triphenyl tetrazolium chloride (unaffected normal myocardium with preserved mitochondrial activity, consistent with reversible zone). Lesion depth increased significantly with increasing CF and the number of PFA burst pulses. An exponential/logarithmic formula combined with CF and the number of PFA burst pulses correlated lesion depth with high accuracy: R=0.809, P <0.0001, ±1.0-mm accuracy in 128 of 163 (79%) lesions, and ±1.5-mm accuracy in 153 of 163 (94%) lesions. Impedance decrease and electrode temperature were poor predictors of lesion size. There were no detectable lesions resulting from ablation without electrode contact., Conclusions: Acute PFA ventricular lesions demonstrate irreversible and reversible lesion boundaries. Electrode-tissue contact is required for effective lesion formation. Lesion depth increases significantly with increasing CF and PFA burst pulses. A new exponential/logarithmic formula combined with CF and the number of PFA burst pulses correlates lesion depth with high accuracy., Competing Interests: Dr Nakagawa is a consultant for Biosense Webster, Inc, Abbott, Inc, Galvanize Therapeutics, Inc, Stereotaxis, Inc, Japan Lifeline, Ltd, and Fukuda Denshi, Ltd. Dr Jackman is a consultant for Biosense Webster, Inc. Drs Farshchi-Heydari, Sharma, and Govari, J. Maffre, C.T. Beeckler, and A. Altman are employees of Biosense Webster, Inc. The other authors report no conflicts.

Competing Interests: K. Martinod and D.D. Wagner are inventors on patents related to NET targeting in thrombosis. K. Martinod has received consulting fees from and has sponsored research agreements with Peel Therapeutics, Inc. D.D. Wagner is on the Scientific Advisory Board of Neutrolis, and her laboratory had sponsored research agreements for testing inhibitors of PAD4 and rhADAMTS13 in thrombosis.

Recently there has been increased use of mechanical circulatory support in pediatric patients as a bridge to cardiopulmonary recovery or transplantation. However, there are few devices that are optimized and approved for use in pediatric patients. We designed and prototyped a novel integrated pediatric pump lung (PPL) that underwent 30 day in-vivo testing in seven juvenile Dorset Hybrid sheep. Devices were implanted in a right atrial to pulmonary artery configuration. Six of seven sheep survived with a device functioning for 25-35 days. The device flow rate was maintained at 2.08 ± 0.34 to 2.54 ± 0.16 L/min with oxygen transfer of 109.8 ± 24.8 to 151.2 ± 26.2 ml/min over the study duration. Aside from a postoperative drop in hematocrit, all hematologic and blood chemistry test values returned to normal ranges after 1-2 weeks postoperatively. Similarly, lactate dehydrogenase increased postoperatively and returned to baseline. In two sheep, there were early device failures due to oxygenator thrombosis on postoperative days zero and five; they then had oxygenator exchanges with subsequent devices performing stably for 30 days. This study demonstrated that the integrated PPL device exhibited stable performance and acceptable biocompatibility in a 30 day ovine model., Competing Interests: Disclosure: Z.J.W. and B.P.G. disclose financial interest in Abiomed-Breethe, Inc. and intellectual property for ECMO systems and blood pumps. A.S. discloses consulting for Abiomed, Inc. and has intellectual property in ECMO cannulas. J.Z. discloses financial interest in intellectual property for ECMO systems and blood pumps. Z.J.W. serves as a consultant for Daiichi Sankyo, Inc. and CH Biomedical USA, Inc. The other authors have no conflicts of interest to report., (Copyright © ASAIO 2024.)

Background: The ubiquitin-proteasome system regulates protein degradation and the development of pulmonary arterial hypertension (PAH), but knowledge about the role of deubiquitinating enzymes in this process is limited. UCHL1 (ubiquitin carboxyl-terminal hydrolase 1), a deubiquitinase, has been shown to reduce AKT1 (AKT serine/threonine kinase 1) degradation, resulting in higher levels. Given that AKT1 is pathological in pulmonary hypertension, we hypothesized that UCHL1 deficiency attenuates PAH development by means of reductions in AKT1., Methods: Tissues from animal pulmonary hypertension models as well as human pulmonary artery endothelial cells from patients with PAH exhibited increased vascular UCHL1 staining and protein expression. Exposure to LDN57444, a UCHL1-specific inhibitor, reduced human pulmonary artery endothelial cell and smooth muscle cell proliferation. Across 3 preclinical PAH models, LDN57444-exposed animals, Uchl1 knockout rats ( Uchl1 -/- ), and conditional Uchl1 knockout mice ( Tie2Cre-Uchl1 fl/fl ) demonstrated reduced right ventricular hypertrophy, right ventricular systolic pressures, and obliterative vascular remodeling. Lungs and pulmonary artery endothelial cells isolated from Uchl1 -/- animals exhibited reduced total and activated Akt with increased ubiquitinated Akt levels. UCHL1-silenced human pulmonary artery endothelial cells displayed reduced lysine(K)63-linked and increased K48-linked AKT1 levels., Results: Supporting experimental data, we found that rs9321, a variant in a GC-enriched region of the UCHL1 gene, is associated with reduced methylation (n=5133), increased UCHL1 gene expression in lungs (n=815), and reduced cardiac index in patients (n=796). In addition, Gadd45α (an established demethylating gene) knockout mice ( Gadd45α -/- ) exhibited reduced lung vascular UCHL1 and AKT1 expression along with attenuated hypoxic pulmonary hypertension., Conclusions: Our findings suggest that UCHL1 deficiency results in PAH attenuation by means of reduced AKT1, highlighting a novel therapeutic pathway in PAH., Competing Interests: None.

Background: A variety of congenital or acquired conditions can cause craniomaxillofacial bone defects, resulting in a heavy financial burden and psychological stress. Guided bone self-generation with periosteum-preserved has great potential for reconstructing large bone defects., Methods: A swine model of guided bone regeneration with occlusive periosteum was established, the rib segment was removed, and the periosteum was sutured to form a closed regeneration chamber. Hematoxylin and eosin staining, Masson's staining, and Safranine O-Fast Green staining were done. Nine-time points were chosen for collecting the periosteum and regenerated bone tissue for gene sequencing. The expression level of each secreted frizzled-related protein (SFRP) member and the correlations among them were analyzed., Results: The process of bone regeneration is almost complete 1 month after surgery, and up to 1 week after surgery is an important interval for initiating the process. The expression of each SFRP family member fluctuated greatly. The highest expression level of all members ranged from 3 days to 3 months after surgery. The expression level of SFRP2 was the highest, and the difference between 2 groups was the largest. Secreted frizzled-related protein 2 and SFRP4 showed a notable positive correlation between the control and model groups. Secreted frizzled-related protein 1, SFRP2, and SFRP4 had a significant spike in fold change at 1 month postoperatively. Secreted frizzled-related protein 1 and SFRP2 had the strongest correlation., Conclusions: This study revealed the dynamic expression of the SFRP family in guided bone regeneration with occlusive periosteum in a swine model, providing a possibility to advance the clinical application of bone defect repair., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Competing Interests: Disclosures None.

Objective: In this study, we aimed to compare the efficiency of different osteotomy techniques for Lefort 1 osteotomy in an experimental caprine skull model., Methods: Twelve caprine skulls were used for the study. Skulls were divided into 3 groups: (1) manual chisel group, (2) Lindemann bur group, and (3) piezo osteotomy group. Bilateral osteotomies were performed on each skull. Results were evaluated with three-dimensional computerized tomography scans and macroscopic observations of the mucosal tears and soft tissue., Results: The mean length of the bone gap in the manual, Lindemann, and piezo groups was 4.8 (±0.7), 3.38 (±1.49), and 1.39 (±0.3) mm, respectively ( P < 0.05). The mean number of comminuted fractures in the manual, Lindemann, and piezo groups was 5.5 (±1.4), 1.6 (±0.3), and 0.6 (±0.5), respectively ( P < 0.05). Mucosal tearing and soft tissue damage based on subjective inspection observations were negligible in the piezo technique. Soft tissue and mucosal damage were observed significantly more in the manual chisel osteotomy method compared with the other 2 techniques., Conclusion: We anticipate that piezo, which has started to be used in new application areas besides rhinoplasty, will continue to be used more widely, especially in reconstructive orthognathic surgery, due to the minimal damage it causes to tissues. With the long-term results, much healthier interpretations can be made., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Background: Unlike conventional microsecond pulsed electrical fields that primarily target the cell membranes, nanosecond pulses are thought to primarily electroporate intracellular organelles. We conducted a comprehensive preclinical assessment of catheter-based endocardial nanosecond pulsed field ablation in swine., Methods: A novel endocardial nanosecond pulsed field ablation system was evaluated in a total of 25 swine. Using either a low-dose (5-second duration) or high-dose (15-second duration) strategy, thoracic veins and discrete atrial and ventricular sites were ablated. Predetermined survival periods were <1 (n=1), ≈2 (n=7), ≈7 (n=6), 14 (n=2), or ≈28 (n=9) days, and venous isolation was assessed before euthanasia. Safety assessments included evaluation of esophageal effects, phrenic nerve function, and changes in venous caliber. All tissues were subject to careful gross pathological and histopathologic examination., Results: All (100%) veins (13 low-dose, 34 high-dose) were acutely isolated, and all reassessed veins (6 low-dose, 15 high-dose) were durably isolated. All examined vein lesions (10 low-dose, 22 high-dose) were transmural. Vein diameters (n=15) were not significantly changed. Of the animals assessed for phrenic palsy (n=9), 3 (33%) demonstrated only transient palsy. There were no differences between dosing strategies. Thirteen mitral isthmus lesions were analyzed, and all 13 (100%) were transmural (depth, 6.4±0.4 mm). Ventricular lesions were 14.7±4.5 mm wide and 7.1±1.3 mm deep, with high-dose lesions deeper than low-dose (7.9±1.2 versus 6.2±0.8 mm; P =0.007). The esophagus revealed nontransmural adventitial surface lesions in 5 of 5 (100%) animals euthanized early (2 days) post-ablation. In the 10 animals euthanized later (14-28 days), all animals demonstrated significant esophageal healing-8 with complete resolution, and 2 with only trace fibrosis., Conclusions: A novel, endocardial nanosecond pulsed field ablation system provides acute and durable venous isolation and linear lesions. Transient phrenic injury and nontransmural esophageal lesions can occur with worst-case assessments suggesting limits to pulsed field ablation tissue selectivity and the need for dedicated assessments during clinical studies., Competing Interests: Dr Reddy is a consultant to Pulse Biosciences. Dr Koruth is a consultant to Pulse Biosciences and has received grant support from Pulse Biosciences. Dr Nies has received a scholarship from the German Research Foundation (Deutsche Forschungsgemeinschaft). Dr Linder is a contractor/consultant paid by Pulse Biosciences to perform the histological evaluation. J. Litt, R. Turovskiy, D.J. Danitz, and D.R. Uecker are paid employees of Pulse Biosciences with stock options. A comprehensive list of all financial disclosures (unrelated to this article) is included in the Supplemental Material. The other authors report no conflicts.

Background: Conventional focal radiofrequency catheters may be modified to enable multiple energy modalities (radiofrequency or pulsed field [PF]) with the benefit of contact force (CF) feedback, providing greater flexibility in the treatment of arrhythmias. Information on the impact of CF on lesion formation in PF ablations remains limited., Methods: An in vivo study was performed with 8 swine using an investigational dual-energy CF focal catheter with local impedance. Experiment I: To evaluate atrial lesion formation, contiguity, and width, a point-by-point approach was used to create an intercaval line. The distance between the points was prespecified at 4±1 mm. Half of the line was created with radiofrequency energy, whereas the other half utilized PF (single 2.0 kV application with a proprietary waveform). Experiment II: To evaluate single application lesion dimensions with a proprietary waveform, discrete ventricular lesions were performed with PFA (single 2.0 kV application) with targeted levels of CF: low, 5 to 15 g; medium, 20 to 30 g; and high, 35 to 45 g. Following 1 week of survival, animals underwent endocardial/epicardial remapping, and euthanasia to enable histopathologic examination., Results: Experiment I: Both energy modalities resulted in a complete intercaval line of transmural ablation. PF resulted in significantly wider lines than radiofrequency: minimum width, 14.9±2.3 versus 5.0±1.6 mm; maximum width, 21.8±3.4 versus 7.3±2.1 mm, respectively; P <0.01 for each. Histology confirmed transmural lesions with both modalities. Experiment II: With PF, lesion depth, width, and volume were larger with higher degrees of CF (depth: r=0.82, P <0.001; width: r=0.26, P =0.052; and volume: r=0.55, P <0.001), with depth increasing at a faster rate than width. The mean depths were as follows: low (n=17), 4.3±1.0 mm; medium (n=26), 6.4±1.2 mm; and high (n=14), 9.1±1.4 mm., Conclusions: Using the same focal point CF-sensing catheter, a novel PF ablation waveform with a single application resulted in transmural atrial lesions that were significantly wider than radiofrequency. Lesion depth showed a significant positive correlation with CF with depths of 6.4 mm at moderate CF., Competing Interests: Disclosures Drs Santangeli, Nakagawa, Saliba, and Wazni have received research grants and consultancy fees from Biosense Webster and Boston Scientific. Dr Hussein has received research grants from Boston Scientific. Dr Nakagawa has received consultancy fees from Galaxy Medical. Dr Garrott, E. Buck, L. Lehn, and R. Kleve are employees of Boston Scientific. The other authors report no conflicts.

Background: Although studies aiming to increase fat graft survival continue, in this study, the authors aimed to investigate the effects of different antioxidants on total antioxidant capacity (TAC) and their effect on graft survival., Methods: Thirty-two male Wistar rats were divided into four equally sized groups, including a control group and three antioxidant groups receiving either melatonin (10 mg/kg), zinc (2 mg/kg), or vitamins E and C (100 mg/kg). Autologous fat grafts (1.7 ± 0.4 g) were transferred to the dorsal subcutaneous region, and total antioxidant capacity was measured on days 0 and 1, week 1, and monthly until the third month. Transferred graft volume and mass (1.3 ± 0.4 g) were measured using the liquid overflow method and precision scales at the end of the study. Routine hematoxylin and eosin staining and immunohistochemistry against perilipin were performed for semiqualitative analysis and H-score for viable adipose cells, respectively., Results: Collected fat grafts measured significantly less in weight and volume and the survival rate was lower in the control group ( P < 0.01). The control group exhibited a reduction in TAC, whereas all groups receiving antioxidants had an increase in TAC during the first week ( P = 0.02, P = 0.008, and P = 0.004 for melatonin, zinc, and vitamins, respectively). Immunohistochemistry of the antioxidant group demonstrated a statistically significant excess and reactivity of cells staining with perilipin antibodies., Conclusion: In this animal study, the beneficial effect of antioxidants on fat graft survival can be related to the significant increase in TAC following the first week of their administration., Clinical Relevance Statement: Antioxidants improve fat graft survival and quality in this rat model, by increasing total antioxidant capacity in the first week of administration., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Background: Cold static storage and normothermic ex vivo heart perfusion are routinely limited to 6 h. This report describes intermittent left atrial (LA) perfusion that allows cardiac functional assessment in a working heart mode., Methods: Using our adult porcine model, general anesthesia was induced and a complete cardiectomy was performed following cardioplegic arrest. Back-table instrumentation was completed and normothermic ex vivo heart perfusion (NEHP) was initiated in a nonworking heart mode (Langendorff). After 1 h of resuscitation and recovery, LA perfusion was initiated and the heart was transitioned to a coronary flow-only working heart mode for 30 min. Baseline working heart parameters were documented and the heart was returned to nonworking mode. Working heart assessments were performed for 30 min every 6 h for 24 h., Results: Twenty-four-hour NEHP on 9 consecutive hearts (280 ± 42.1 g) was successful and no significant differences were found between working heart parameters at baseline and after 24 h of perfusion. There was no difference between initial and final measurements of LA mean pressures (5.0 ± 3.1 versus 9.0 ± 6.5 mm Hg, P  = 0.22), left ventricular systolic pressures (44.3 ± 7.2 versus 39.1 ± 9.0 mm Hg, P  = 0.13), mean aortic pressures (30.9 ± 5.8 versus 28.1 ± 8.1 mm Hg, P  = 0.37), and coronary resistance (0.174 ± 0.046 versus 0.173 ± 0.066 mL/min/g, P  = 0.90). There were also no significant differences between lactate (2.4 ± 0.5 versus 2.6 ± 0.4 mmol/L, P  = 0.17) and glucose (173 ± 75 versus 156 ± 70 mg/dL, P  = 0.37)., Conclusions: A novel model using intermittent LA perfusion to create a coronary flow-only working heart mode for assessment of ex vivo cardiac function has been successfully developed., Competing Interests: R.H.B. and A.R.-P. received supplies from Xvivo and Terumo for the ECLS Lab. A.R.-P. is member of the Advisory Board of the New Leadership Academy, University of Utah, and is a paid consultant with Terumo Cardiovascular. D.E.M. is the owner of Daris LLC, which sold the Mflow Organ Perfusion System to the University of Michigan. D.E.M. also has patents pending on an Automatic Perfusion System and a Method for rapid and accurate determination of average fluid circuit pressure and flowrate. D.H.D. receives royalties from Thompson Surgical and has unpaid board and committee positions with the American Association for Thoracic Surgery, American Society of Echocardiography, and Society of Thoracic Surgeons. The other authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Wildfire smoke (WFS) is a mixture of respirable particulate matter, environmental gases, and other hazardous pollutants that originate from the unplanned burning of arid vegetation during wildfires. The increasing size and frequency of recent wildfires has escalated public and occupational health concerns regarding WFS inhalation, by either individuals living nearby and downstream an active fire or wildland firefighters and other workers that face unavoidable exposure because of their profession. In this review, we first synthesize current evidence from environmental, controlled, and interventional human exposure studies, to highlight positive associations between WFS inhalation and cardiovascular morbidity and mortality. Motivated by these findings, we discuss preventative measures and suggest interventions to mitigate the cardiovascular impact of wildfires. We then review animal and cell exposure studies to call attention on the pathophysiological processes that support the deterioration of cardiovascular tissues and organs in response to WFS inhalation. Acknowledging the challenges of integrating evidence across independent sources, we contextualize laboratory-scale exposure approaches according to the biological processes that they model and offer suggestions for ensuring relevance to the human condition. Noting that wildfires are significant contributors to ambient air pollution, we compare the biological responses triggered by WFS to those of other harmful pollutants. We also review evidence for how WFS inhalation may trigger mechanisms that have been proposed as mediators of adverse cardiovascular effects upon exposure to air pollution. We finally conclude by highlighting research areas that demand further consideration. Overall, we aspire for this work to serve as a catalyst for regulatory initiatives to mitigate the adverse cardiovascular effects of WFS inhalation in the community and alleviate the occupational risk in wildland firefighters., Competing Interests: Disclosures None.

Background: Ethical and financial considerations have encouraged the use of nonliving models for simulation-based training in microsurgery, such as commercially available chicken thighs. The purpose of this study was to compare the nonliving chicken thigh model to the one currently considered as the standard-namely, the living rat model-in the setting of an initiation microsurgery course., Methods: Applicants to the 3-day basic microsurgery course of the Paris School of Surgery were assigned randomly to either one group that received the regular training of the school (RT group), including four hands-on sessions using only living rat models, or one group that received a modified curriculum in which a nonliving chicken thigh model was used for the first hands-on session (CT group). During the following session, all trainees were evaluated on living rat models, using a global rating scale and two task-specific scales (knot-tying and anastomosis); rates of anastomosis patency, animal survival, and technique completion were recorded., Results: Ninety-three residents were enrolled. Global rating scale, knot-tying, and anastomosis task-specific scale scores were significantly higher in the CT group ( n = 51) than in the RT group, with mean differences of 2.6 points ( P = 0.0001), 1.3 points ( P < 0.0001), and 1.4 points ( P < 0.0001), respectively. Patency and survival rates were significantly higher in the CT group than in the RT group, with mean differences of 22% ( P = 0.0020) and 27% ( P < 0.0001), respectively; completion rates were not statistically different., Conclusion: Subject to the use of validated models, such as the chicken thigh, nonliving animal models are a suitable alternative to the living rat model in microsurgery initial training., Clinical Relevance Statement: The use of validated non-living models, such as the chicken thigh, is a suitable alternative to the living rat model in microsurgery initial training., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Summary: Although supermicrosurgery techniques are essential skills for lymphatic surgery or perforator-flap surgery, an ideal training model is yet to be introduced. Living animal models, such as rodents, are considered to be ideal microsurgical training models. However, the use of living animal models is costly and involves bioethical considerations. Hence, the authors developed a novel, cost-effective, highly reproducible, and easy-to-handle supermicrosurgical anastomosis training system using the chicken embryo within the egg-in-cube system. Chick embryos were fertilized in the artificial cubic eggshell, which was fabricated by integrating a polycarbonate frame structure and five polydimethylsiloxane membranes. Seven days later, the trainees underwent supermicrosurgical training using the vitelline artery of the chick embryo. The trainees were able to perform supermicrosurgical training using all 11 surviving chicken embryos. The average diameter of the vitelline artery was 0.43 mm. Patency and pulsation were observed after the anastomosis in four of the 11 cases. The supermicrosurgical training system using the chicken embryo within the egg-in-cube system has several advantages. This system is ethically acceptable, less costly and easier to manage than other animal models, and suitable as a supermicrosurgical training model, such as for lymphovenular anastomosis, because the diameter of the vitelline artery was similar to that of the lymphatic vessels in patients with lymphedema. Moreover, the trainee can confirm patency and leakage after the anastomosis because this model has a circulation system. The trainee can practice the supermicrosurgical technique efficiently with simultaneous feedback on anastomosis results., Clinical Relevance Statement: This study introduces a novel, cost-effective supermicrosurgical training system using chicken embryos within an egg-in-cube, offering a practical and ethical alternative. Its close simulation to human lymphatic vessels supports skill enhancement for practicing surgeons., (Copyright © 2023 by the American Society of Plastic Surgeons.)

The same is found in atherosclerosis neointimal lesions (Figure [H and I]), suggesting that this pattern of vWF localization and I VWF/Vwf i transcription is a general characteristic of neointimal lesions in both the systemic and pulmonary vascular beds. Keywords: hypertension, pulmonary; models, animal; vascular remodeling; von Willebrand Factor EN hypertension, pulmonary models, animal vascular remodeling von Willebrand Factor 429 431 3 08/02/22 20220802 NES 220802 vWF (von Willebrand Factor) is a large, secreted, multimeric glycoprotein transcribed by vascular endothelial cells and, to a lesser extent, megakaryocytes throughout the body. [Extracted from the article]

Background: Current paradigms suggest that nitric oxide (NO) produced by endothelial cells (ECs) through endothelial nitric oxide synthase (eNOS) in the vessel wall is the primary regulator of blood flow and blood pressure. However, red blood cells (RBCs) also carry a catalytically active eNOS, but its role is controversial and remains undefined. This study aimed to elucidate the functional significance of RBC eNOS compared with EC eNOS for vascular hemodynamics and nitric oxide metabolism.Methods: We generated tissue-specific loss- and gain-of-function models for eNOS by using cell-specific Cre-induced gene inactivation or reactivation. We created 2 founder lines carrying a floxed eNOS (eNOSflox/flox) for Cre-inducible knockout (KO), and gene construct with an inactivated floxed/inverted exon (eNOSinv/inv) for a Cre-inducible knock-in (KI), which respectively allow targeted deletion or reactivation of eNOS in erythroid cells (RBC eNOS KO or RBC eNOS KI mice) or in ECs (EC eNOS KO or EC eNOS KI mice). Vascular function, hemodynamics, and nitric oxide metabolism were compared ex vivo and in vivo.Results: The EC eNOS KOs exhibited significantly impaired aortic dilatory responses to acetylcholine, loss of flow-mediated dilation, and increased systolic and diastolic blood pressure. RBC eNOS KO mice showed no alterations in acetylcholine-mediated dilation or flow-mediated dilation but were hypertensive. Treatment with the nitric oxide synthase inhibitor Nγ-nitro-l-arginine methyl ester further increased blood pressure in RBC eNOS KOs, demonstrating that eNOS in both ECs and RBCs contributes to blood pressure regulation. Although both EC eNOS KOs and RBC eNOS KOs had lower plasma nitrite and nitrate concentrations, the levels of bound NO in RBCs were lower in RBC eNOS KOs than in EC eNOS KOs. Reactivation of eNOS in ECs or RBCs rescues the hypertensive phenotype of the eNOSinv/inv mice, whereas the levels of bound NO were restored only in RBC eNOS KI mice.Conclusions: These data reveal that eNOS in ECs and RBCs contribute independently to blood pressure homeostasis. [ABSTRACT FROM AUTHOR]

Summary: Fully implantable electronic devices in freely roaming animal models are useful in biomedical research, but their development is prohibitively resource intensive for many laboratories. The advent of miniaturized microcontrollers with onboard wireless data exchange capabilities has enabled cost-efficient development of myriad do-it-yourself electronic devices that are easily customizable with open-source software ( https://www.arduino.cc/ ). Likewise, the global proliferation of mobile devices has led to the development of low-cost miniaturized wireless power technology. The authors present a low-cost, rechargeable, and fully implantable electronic device comprising a commercially available, open-source, wirelessly powered microcontroller that is readily customizable with myriad readily available miniature sensors and actuators. The authors demonstrate the utility of this platform for chronic nerve stimulation in the freely roaming rat with intermittent wireless charging over 4 weeks. Device assembly was achieved within 2 hours and necessitated only basic soldering equipment. Component costs totaled $115 per device. Wireless data transfer and wireless recharging of device batteries was achieved within 30 minutes, and no harmful heat generation occurred during charging or discharging cycles, as measured by external thermography and internal device temperature monitoring. Wireless communication enabled triggered cathodic pulse stimulation of the facial nerve at various user-selected programmed frequencies (1, 5, and 10 Hz) for periods of 4 weeks or longer. This implantable electronic platform could be further miniaturized and expanded to study a vast array of biomedical research questions in live animal models., Clinical Relevance Statement: The clinical relevance of electrical stimulation in neural recovery remains controversial, and long-term neural stimulation in small animal models is challenging. We have developed a low-cost, fully implantable, wirelessly powered nerve stimulation device to facilitate further research in nerve stimulation in animal models., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Background: Ex vivo machine perfusion is a novel preservation technique for storing and assessing marginal kidney grafts. All ex vivo perfusion techniques have advantages and shortcomings. The current study analyzed whether a combination of oxygenated hypothermic machine perfusion (oxHMP) followed by a short period of normothermic ex vivo kidney perfusion (NEVKP) could combine the advantages of both techniques., Methods: Porcine kidneys were exposed to 30 min of warm ischemia followed by perfusion. Kidneys underwent either 16-h NEVKP or 16-h oxHMP. The third group was exposed to 16-h oxHMP followed by 3-h NEVKP (oxHMP + NEVKP group). After contralateral nephrectomy, grafts were autotransplanted and animals were followed up for 8 d., Results: All animals survived the follow-up period. Grafts preserved by continuous NEVKP showed improved function with lower peak serum creatinine and more rapid recovery compared with the other 2 groups. Urine neutrophil gelatinase-associated lipocalin, a marker of kidney injury, was found to be significantly lowered on postoperative day 3 in the oxHMP + NEVKP group compared with the other 2 groups., Conclusions: A short period of NEVKP after oxHMP provides comparable short-term outcomes to prolonged NEVKP and is superior to oxHMP alone. A combination of oxHMP with end-ischemic NEVKP could be an attractive, practical strategy to combine the advantages of both preservation techniques., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Primary aldosteronism is a frequent form of endocrine hypertension caused by aldosterone overproduction from the adrenal cortex. Regulation of aldosterone biosynthesis has been studied in rodents despite differences in adrenal physiology with humans. We, therefore, investigated pig adrenal steroidogenesis, morphology, and transcriptome profiles of the zona glomerulosa (zG) and zona fasciculata in response to activation of the renin-angiotensin-aldosterone system by dietary sodium restriction. Six-week-old pigs were fed a low- or high-sodium diet for 14 days (3 pigs per group, 0.4 g sodium/kg feed versus 6.8 g sodium/kg). Plasma aldosterone concentrations displayed a 43-fold increase (P=0.011) after 14 days of sodium restriction (day 14 versus day 0). Low dietary sodium caused a 2-fold increase in thickness of the zG (P<0.001) and an almost 3-fold upregulation of CYP11B (P<0.05) compared with high dietary sodium. Strong immunostaining of the KCNJ5 (G protein-activated inward rectifier potassium channel 4), which is frequently mutated in primary aldosteronism, was demonstrated in the zG. mRNA sequencing transcriptome analysis identified significantly altered expression of genes modulated by the renin-angiotensin-aldosterone system in the zG (n=1172) and zona fasciculata (n=280). These genes included many with a known role in the regulation of aldosterone synthesis and adrenal function. The most highly enriched biological pathways in the zG were related to cholesterol biosynthesis, steroid metabolism, cell cycle, and potassium channels. This study provides mechanistic insights into the physiology and pathophysiology of aldosterone production in a species closely related to humans and shows the suitability of pigs as a translational animal model for human adrenal steroidogenesis. [ABSTRACT FROM AUTHOR]

Background: Smooth muscle cells (SMC) play a critical role in atherosclerosis. The Aryl hydrocarbon receptor (AHR) is an environment-sensing transcription factor that contributes to vascular development, and has been implicated in coronary artery disease risk. We hypothesized that AHR can affect atherosclerosis by regulating phenotypic modulation of SMC.Methods: We combined RNA-sequencing, chromatin immunoprecipitation followed by sequencing, assay for transposase-accessible chromatin using sequencing, and in vitro assays in human coronary artery SMCs, with single-cell RNA-sequencing, histology, and RNAscope in an SMC-specific lineage-tracing Ahr knockout mouse model of atherosclerosis to better understand the role of AHR in vascular disease.Results: Genomic studies coupled with functional assays in cultured human coronary artery SMCs revealed that AHR modulates the human coronary artery SMC phenotype and suppresses ossification in these cells. Lineage-tracing and activity-tracing studies in the mouse aortic sinus showed that the Ahr pathway is active in modulated SMCs in the atherosclerotic lesion cap. Furthermore, single-cell RNA-sequencing studies of the SMC-specific Ahr knockout mice showed a significant increase in the proportion of modulated SMCs expressing chondrocyte markers such as Col2a1 and Alpl, which localized to the lesion neointima. These cells, which we term "chondromyocytes," were also identified in the neointima of human coronary arteries. In histological analyses, these changes manifested as larger lesion size, increased lineage-traced SMC participation in the lesion, decreased lineage-traced SMCs in the lesion cap, and increased alkaline phosphatase activity in lesions in the Ahr knockout in comparison with wild-type mice. We propose that AHR is likely protective based on these data and inference from human genetic analyses.Conclusions: Overall, we conclude that AHR promotes the maintenance of lesion cap integrity and diminishes the disease-related SMC-to-chondromyocyte transition in atherosclerotic tissues. [ABSTRACT FROM AUTHOR]

Delirium is an acute brain disorder associated with disorganized thinking, difficulty focusing, and confusion that commonly follows major surgery, severe infection, and illness. Older patients are at high risk for developing delirium during hospitalization, which may contribute to increased morbidity, longer hospitalization, and increased risk of institutionalization following discharge. The pathophysiology underlying delirium remains poorly studied. This review delves into the findings from biomarker studies and animal models, and highlights the potential for tissue-engineered models of the brain in studying this condition. The aim is to bring together the existing knowledge in the field and provide insight into the future direction of delirium research., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 International Anesthesia Research Society.)

Background: Remuscularization of the mammalian heart can be achieved after cell transplantation of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs). However, several hurdles remain before implementation into clinical practice. Poor survival of the implanted cells is related to insufficient vascularization, and the potential for fatal arrhythmogenesis is associated with the fetal cell-like nature of immature CMs., Methods: We generated 3 lines of hiPSC-derived endothelial cells (ECs) and hiPSC-CMs from 3 independent donors and tested hiPSC-CM sarcomeric length, gap junction protein, and calcium-handling ability in coculture with ECs. Next, we examined the therapeutic effect of the cotransplantation of hiPSC-ECs and hiPSC-CMs in nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice undergoing myocardial infarction (n≥4). Cardiac function was assessed by echocardiography, whereas arrhythmic events were recorded using 3-lead ECGs. We further used healthy non-human primates (n=4) with cell injection to study the cell engraftment, maturation, and integration of transplanted hiPSC-CMs, alone or along with hiPSC-ECs, by histological analysis. Last, we tested the cell therapy in ischemic reperfusion injury in non-human primates (n=4, 3, and 4 for EC+CM, CM, and control, respectively). Cardiac function was evaluated by echocardiography and cardiac MRI, whereas arrhythmic events were monitored by telemetric ECG recorders. Cell engraftment, angiogenesis, and host-graft integration of human grafts were also investigated., Results: We demonstrated that human iPSC-ECs promote the maturity and function of hiPSC-CMs in vitro and in vivo. When cocultured with ECs, CMs showed more mature phenotypes in cellular structure and function. In the mouse model, cotransplantation augmented the EC-accompanied vascularization in the grafts, promoted the maturity of CMs at the infarct area, and improved cardiac function after myocardial infarction. Furthermore, in non-human primates, transplantation of ECs and CMs significantly enhanced graft size and vasculature and improved cardiac function after ischemic reperfusion., Conclusions: These results demonstrate the synergistic effect of combining iPSC-derived ECs and CMs for therapy in the postmyocardial infarction heart, enabling a promising strategy toward clinical translation., Competing Interests: Disclosures None.

Purpose of Review: This article reviews recent advances and controversies of developmental anesthesia neurotoxicity research with a special focus on the unanswered questions in the field both from clinical and preclinical perspectives., Recent Findings: Observational cohort studies of prenatal and early childhood exposure to anesthesia have reported mixed evidence of an association with impaired neurodevelopment. Meta-analyses of currently available studies of early childhood exposure to anesthesia suggest that, while limited to no change in general intelligence can be detected, more subtle deficits in specific neurodevelopmental domains including behavior and executive function may be seen. Several studies have evaluated intraoperative blood pressure values and neurocognitive outcomes and have not found an association. Although many animal studies have been performed, taking into consideration other peri-operative exposures such as pain and inflammation may help with translation of results from animal models to humans., Summary: Advances have been made in the field of developmental anesthetic neurotoxicity over the past few years, including the recognition that anesthetic exposure is associated with deficits in certain cognitive domains but not others. Although the most important question of whether anesthetic agents actually cause long-term neurodevelopmental effects in children has still not been answered, results from recent studies will guide further studies necessary to inform clinical decision-making in children., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Radiofrequency renal denervation is under investigation for treatment of hypertension with variable success. We developed preclinical models to examine the dependence of ablation biomarkers on renal denervation treatment parameters and anatomic variables. One hundred twenty-nine porcine renal arteries were denervated with an irrigated radiofrequency catheter with multiple helically arrayed electrodes. Nerve effects and ablation geometries at 7 days were characterized histomorphometrically and correlated with associated renal norepinephrine levels. Norepinephrine exhibited a threshold dependence on the percentage of affected nerves across the range of treatment durations (30-60 s) and power set points (6-20 W). For 15 W/30 s treatments, norepinephrine reduction and percentage of affected nerves tracked with number of electrode treatments, confirming additive effects of helically staggered ablations. Threshold effects were only attained when ≥4 electrodes were powered. Histomorphometry and computational modeling both illustrated that radiofrequency treatments directed at large neighboring veins resulted in subaverage ablation areas and, therefore, contributed suboptimally to efficacy. Account for measured nerve distribution patterns and the annular geometry of the artery revealed that, regardless of treatment variables, total ablation area and circumferential coverage were the prime determinants of renal denervation efficacy, with increased efficacy at smaller diameters. [ABSTRACT FROM AUTHOR]

Background: The actin-binding protein FLNA (filamin A) regulates signal transduction important for cell locomotion, but the role of macrophage-specific FLNA during atherogenesis has not been explored.Methods: We analyzed FLNA expression in human carotid atherosclerotic plaques by immunofluorescence. We also produced mice with Flna-deficient macrophages by breeding conditional Flna-knockout mice ( Flna o/fl) with mice expressing Cre from the macrophage-specific lysosome M promoter ( LC). Atherosclerosis in vivo was studied by transplanting bone marrow from male Flna o/fl/ LC mice to atherogenic low-density lipoprotein receptor-deficient ( Ldlr-/-) mice; and by infecting Flna o/fl and Flna o/fl/ LC mice with AdPCSK9 (adenoviral vector overexpressing proprotein convertase subtilisin/kexin type 9). Furthermore, C57BL/6 mice were infected with AdPCSK9 and then treated with the calpain inhibitor calpeptin to inhibit FLNA cleavage.Results: We found that macrophage FLNA expression was higher in advanced than in intermediate human atherosclerotic plaques. Flna o/fl/ LC macrophages proliferated and migrated less than controls; expressed lower levels of phosphorylated AKT and ERK1/2; exhibited reduced foam cell formation and lipid uptake; and excreted more lipids. The deficiency of Flna in macrophages markedly reduced the size of aortic atherosclerotic plaques in both Ldlr-/-BMT: Flnao/fl/LC and AdPCSK9-infected Flna o/fl/ LC mice. Intima/media ratios and numbers of CD68-positive macrophages in atherosclerotic plaques were lower in Flna-deficient mice than in control mice. Moreover, we found that STAT3 interacts with a calpain-cleaved carboxyl-terminal fragment of FLNA. Inhibiting calpain-mediated FLNA cleavage with calpeptin in macrophages reduced nuclear levels of phosphorylated STAT3, interleukin 6 secretion, foam cell formation, and lipid uptake. Finally, calpeptin treatment reduced the size of atherosclerotic plaques in C57BL/6 mice infected with AdPCSK9.Conclusions: Genetic inactivation of Flna and chemical inhibition of calpain-dependent cleavage of FLNA impaired macrophage signaling and function, and reduced atherosclerosis in mice, suggesting that drugs targeting FLNA may be useful in the treatment of atherosclerosis. [ABSTRACT FROM AUTHOR]

Emerging preclinical data suggest that splanchnic sympathetic nerve activation may play an important role in the pathophysiology of hypertension. We sought to determine the potential therapeutic application of catheter-based splanchnic denervation in a clinically relevant large animal model of hypertensive cardiomyopathy (hCMP). Sustained elevated blood pressure was induced in adult pigs using a combination of intravenous infusion of Ang II (angiotensin II) and subcutaneous implantation of deoxycorticosterone acetate pellets to establish a large animal model of hCMP. Serial changes in cardiac echocardiographic and invasive hemodynamic parameters and neurohumoral biomarkers were investigated in animals with hypertension alone (n=9) and hypertension with catheter-based splanchnic denervation (n=6). Another 6 pigs without hypertension induction served as controls. At 10 weeks, hypertensive animals developed sustained elevated blood pressure and phenotype of hCMP with significant systolic and diastolic dysfunction, and left ventricular remodeling and hypertrophy as determined by invasive hemodynamic and echocardiogram assessments, respectively, and increased venoarterial norepinephrine gradient over the myocardium, kidneys, and splanchnic organs compared with baseline. Catheter-based splanchnic denervation decreased the venoarterial norepinephrine gradient over the splanchnic organs associated with the reduced splenic sympathetic nerve innervation; attenuated the elevated blood pressure, left ventricular remodeling, and hypertrophy; and preserved left ventricular systolic and diastolic function at 20 weeks in pigs with hCMP. Our results provide novel mechanistic insight into the role of splenic sympathetic nerve innervation in hypertension and important proof-of-principle data for the therapeutic application of catheter-based splanchnic denervation in a large animal model of hCMP. [ABSTRACT FROM AUTHOR]

Hypertension is the most common chronic disease in the world, yet the precise cause of elevated blood pressure often cannot be determined. Animal models have been useful for unraveling the pathogenesis of hypertension and for testing novel therapeutic strategies. The utility of animal models for improving the understanding of the pathogenesis, prevention, and treatment of hypertension and its comorbidities depends on their validity for representing human forms of hypertension, including responses to therapy, and on the quality of studies in those models (such as reproducibility and experimental design). Important unmet needs in this field include the development of models that mimic the discrete hypertensive syndromes that now populate the clinic, resolution of ongoing controversies in the pathogenesis of hypertension, and the development of new avenues for preventing and treating hypertension and its complications. Animal models may indeed be useful for addressing these unmet needs. [ABSTRACT FROM AUTHOR]

Background: Titin is a giant elastic protein that spans the half-sarcomere from Z-disk to M-band. It acts as a molecular spring and mechanosensor and has been linked to striated muscle disease. The pathways that govern titin-dependent cardiac growth and contribute to disease are diverse and difficult to dissect.Methods: To study titin deficiency versus dysfunction, the authors generated and compared striated muscle specific knockouts (KOs) with progressive postnatal loss of the complete titin protein by removing exon 2 (E2-KO) or an M-band truncation that eliminates proper sarcomeric integration, but retains all other functional domains (M-band exon 1/2 [M1/2]-KO). The authors evaluated cardiac function, cardiomyocyte mechanics, and the molecular basis of the phenotype.Results: Skeletal muscle atrophy with reduced strength, severe sarcomere disassembly, and lethality from 2 weeks of age were shared between the models. Cardiac phenotypes differed considerably: loss of titin leads to dilated cardiomyopathy with combined systolic and diastolic dysfunction-the absence of M-band titin to cardiac atrophy and preserved function. The elastic properties of M1/2-KO cardiomyocytes are maintained, while passive stiffness is reduced in the E2-KO. In both KOs, we find an increased stress response and increased expression of proteins linked to titin-based mechanotransduction (CryAB, ANKRD1, muscle LIM protein, FHLs, p42, Camk2d, p62, and Nbr1). Among them, FHL2 and the M-band signaling proteins p62 and Nbr1 are exclusively upregulated in the E2-KO, suggesting a role in the differential pathology of titin truncation versus deficiency of the full-length protein. The differential stress response is consistent with truncated titin contributing to the mechanical properties in M1/2-KOs, while low titin levels in E2-KOs lead to reduced titin-based stiffness and increased strain on the remaining titin molecules.Conclusions: Progressive depletion of titin leads to sarcomere disassembly and atrophy in striated muscle. In the complete knockout, remaining titin molecules experience increased strain, resulting in mechanically induced trophic signaling and eventually dilated cardiomyopathy. The truncated titin in M1/2-KO helps maintain the passive properties and thus reduces mechanically induced signaling. Together, these findings contribute to the molecular understanding of why titin mutations differentially affect cardiac growth and have implications for genotype-phenotype relations that support a personalized medicine approach to the diverse titinopathies. [ABSTRACT FROM AUTHOR]

Background: Monoallelic mutations in the gene encoding bone morphogenetic protein receptor 2 ( Bmpr2) are the main genetic risk factor for heritable pulmonary arterial hypertension (PAH) with incomplete penetrance. Several Bmpr2 transgenic mice have been reported to develop mild spontaneous PAH. In this study, we examined whether rats with the Bmpr2 mutation were susceptible to developing more severe PAH.Methods: The zinc finger nuclease method was used to establish rat lines with mutations in the Bmpr2 gene. These rats were then characterized at the hemodynamic, histological, electrophysiological, and molecular levels.Results: Rats with a monoallelic deletion of 71 bp in exon 1 (Δ 71 rats) showed decreased BMPRII expression and phosphorylated SMAD1/5/9 levels. Δ 71 Rats develop age-dependent spontaneous PAH with a low penetrance (16%-27%), similar to that in humans. Δ 71 Rats were more susceptible to hypoxia-induced pulmonary hypertension than wild-type rats. Δ 71 Rats exhibited progressive pulmonary vascular remodeling associated with a proproliferative phenotype and showed lower pulmonary microvascular density than wild-type rats. Organ bath studies revealed severe alteration of pulmonary artery contraction and relaxation associated with potassium channel subfamily K member 3 (KCNK3) dysfunction. High levels of perivascular fibrillar collagen and pulmonary interleukin-6 overexpression discriminated rats that developed spontaneous PAH and rats that did not develop spontaneous PAH. Finally, detailed assessments of cardiomyocytes demonstrated alterations in morphology, calcium (Ca2+), and cell contractility specific to the right ventricle; these changes could explain the lower cardiac output of Δ 71 rats. Indeed, adult right ventricular cardiomyocytes from Δ 71 rats exhibited a smaller diameter, decreased sensitivity of sarcomeres to Ca2+, decreased [Ca2+] transient amplitude, reduced sarcoplasmic reticulum Ca2+ content, and short action potential duration compared with right ventricular cardiomyocytes from wild-type rats.Conclusions: We characterized the first Bmpr2 mutant rats and showed some of the critical cellular and molecular dysfunctions described in human PAH. We also identified the heart as an unexpected but potential target organ of Bmpr2 mutations. Thus, this new genetic rat model represents a promising tool to study the pathogenesis of PAH. [ABSTRACT FROM AUTHOR]

Keywords: cell- and tissue-based therapy; models, animal; myocardial infarction; stem cells; translational research EN cell- and tissue-based therapy models, animal myocardial infarction stem cells translational research 1037 1039 3 04/20/20 20200324 NES 200324 Cardiac cell therapy using adult cells with stem- or progenitor-like properties has been under clinical investigation for more than 15 years. MNCs were largely absent from all tissues examined, including heart and lung (Figure, C), accounting for less than 3 cells per milligram tissue weight, or roughly 450 MNCs in an entire mouse heart. [Extracted from the article]

Subarachnoid hemorrhage (SAH) is an acute catastrophic neurological disorder with high morbidity and mortality. Ferroptosis is one of the pathophysiological processes during secondary brain injury of SAH, which could be inhibited by ferrostatin-1 (Fer-1) effectively. Peroxiredoxin6 (PRDX6) is an antioxidant protein and is currently proven to be associated with lipid peroxidation in ferroptosis except in GSH/GPX4 and FSP1/CoQ10 antioxidant systems. However, the alteration and function of PRDX6 in SAH are still unknown. In addition, whether PRDX6 is involved in the neuroprotection of Fer-1 in SAH is yet to be investigated. Endovascular perforation was employed to induce the SAH model. Fer-1 and in vivo siRNA aiming to knockdown PRDX6 were administrated intracerebroventricularly to investigate relevant regulation and mechanism. We confirmed the inhibition of ferroptosis and neuroprotection from brain injury by Fer-1 in SAH. The induction of SAH reduced the expression of PRDX6, which could be alleviated by Fer-1. Accordingly, dysregulated lipid peroxidation indicated by GSH and MDA was improved by Fer-1, which was counteracted by si-PRDX6. Similarly, the neuroprotection of Fer-1 in SAH was diminished by the knockdown of PRDX6 and the administration of a calcium-independent phospholipase A2 (iPLA2) inhibitor. PRDX6 is involved in ferroptosis induced by SAH and is associated with Fer-1 neuroprotection from brain injury via its iPLA2 activity., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Purpose of Review: Postoperative adhesions remain a clinical challenge to both patients and providers, as they are associated with significant complications and a high economic burden. This article provides a clinical review of currently available antiadhesive agents and promising new therapies that have advanced past animal studies., Recent Findings: Several agents have been investigated on their ability to reduce adhesion formation; however, there is no widely acceptable option. The few available interventions are barrier agents and while low-quality evidence suggests that they may be more effective than no treatment, there is no general agreement on their overall efficacy. There is an abundance of research on new solutions; however, their clinical efficacy is yet to be determined., Summary: Although a wide range of therapeutics have been investigated, majority are halted in animal models with only a select few being studied in humans and ultimately available in the market. Many agents have shown effectiveness in reducing adhesion formation, however, that has not been translated to improvement in clinically relevant outcomes; hence the need for high-quality large randomized trials., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Both single- and double-outflow cavopulmonary assist devices (CPADs) were recently proposed for the Fontan population, whereas single-outflow configurations were evaluated in large animal trials and double-outflow concepts are lacking an equivalent in vivo assessment. The aim of this study was to test the hemodynamic properties of a double-outflow CPAD device in an acute sheep model. The two inflow cannulae of a CPAD were anastomosed to the caval veins. Outflow graft connection was performed via end-to-side anastomosis to the right (RPA) and main pulmonary artery (MPA). Speed ramp protocols were conducted, and hemodynamic effects were monitored in terms of caval flows, cardiac output (CO), central venous pressure (CVP), pulmonary artery pressure (PAP), and left atrial pressure (LAP). Six experiments were conducted (53.35 ± 5.1 kg). In three experiments, the animal model was established, the CPAD was examined, and restoration of biventricular equivalency in terms of venous return was achieved. Venous pressures (CVP) declined linearly with increasing pump speed (r > 0.879), whereas caval flow (r > 0.973), CO (r > 0.993), PAP (r > 0.973), and LAP (r > 0.408) increased. Despite the considerable complexity of the sheep model caused by the sheep pulmonary arterial anatomy that requires substantial graft bending, the CPAD was evaluated in three acute experiments and showed the potential to completely substitute a subpulmonary ventricle., Competing Interests: Disclosure: M.G. received personal fees and research grants from BerlinHeart GmbH and research grants from 4Fontan AG; T.S. received personal fees and grants from Abbott, Medtronic, CorWave. U.K. received grants from Berlin Heart GmbH; D.Z. received personal fees from Abbott, Medtronic, Abiomed, Edwards, Daiichi Sankyo and research grants from Abbott, Medtronic, Berlin Heart, Edwards, Corcym. The other authors have no conflicts of interest to report., (Copyright © ASAIO 2023.)

Background: Progerin, an aberrant protein that accumulates with age, causes the rare genetic disease Hutchinson-Gilford progeria syndrome (HGPS). Patients who have HGPS exhibit ubiquitous progerin expression, accelerated aging and atherosclerosis, and die in their early teens, mainly of myocardial infarction or stroke. The mechanisms underlying progerin-induced atherosclerosis remain unexplored, in part, because of the lack of appropriate animal models.Methods: We generated an atherosclerosis-prone model of HGPS by crossing apolipoprotein E-deficient (Apoe-/-) mice with LmnaG609G/G609G mice ubiquitously expressing progerin. To induce progerin expression specifically in macrophages or vascular smooth muscle cells (VSMCs), we crossed Apoe-/-LmnaLCS/LCS mice with LysMCre and SM22αCre mice, respectively. Progerin expression was evaluated by polymerase chain reaction and immunofluorescence. Cardiovascular alterations were determined by immunofluorescence and histology in male mice fed normal chow or a high-fat diet. In vivo low-density lipoprotein retention was assessed by intravenous injection of fluorescently labeled human low-density lipoprotein. Cardiac electric defects were evaluated by electrocardiography.Results: Apoe-/-LmnaG609G/G609G mice with ubiquitous progerin expression exhibited a premature aging phenotype that included failure to thrive and shortened survival. In addition, high-fat diet-fed Apoe-/-LmnaG609G/G609G mice developed a severe vascular pathology, including medial VSMC loss and lipid retention, adventitial fibrosis, and accelerated atherosclerosis, thus resembling most aspects of cardiovascular disease observed in patients with HGPS. The same vascular alterations were also observed in Apoe-/-LmnaLCS/LCSSM22αCre mice expressing progerin specifically in VSMCs, but not in Apoe-/-LmnaLCS/LCSLysMCre mice with macrophage-specific progerin expression. Moreover, Apoe-/-LmnaLCS/LCSSM22αCre mice had a shortened lifespan despite the lack of any overt aging phenotype. Aortas of ubiquitously and VSMC-specific progerin-expressing mice exhibited increased retention of fluorescently labeled human low-density lipoprotein, and atheromata in both models showed vulnerable plaque features. Immunohistopathological examination indicated that Apoe-/-LmnaLCS/LCSSM22αCre mice, unlike Apoe-/-LmnaG609G/G609G mice, die of atherosclerosis-related causes.Conclusions: We have generated the first mouse model of progerin-induced atherosclerosis acceleration, and demonstrate that restricting progerin expression to VSMCs is sufficient to accelerate atherosclerosis, trigger plaque vulnerability, and reduce lifespan. Our results identify progerin-induced VSMC death as a major factor triggering atherosclerosis and premature death in HGPS. [ABSTRACT FROM AUTHOR]

Viral infections are a leading cause of myocarditis and pericarditis worldwide, conditions that frequently coexist. Myocarditis and pericarditis were some of the early comorbidities associated with SARS-CoV-2 infection and COVID-19. Many epidemiologic studies have been conducted since that time concluding that SARS-CoV-2 increased the incidence of myocarditis/pericarditis at least 15× over pre-COVID levels although the condition remains rare. The incidence of myocarditis pre-COVID was reported at 1 to 10 cases/100 000 individuals and with COVID ranging from 150 to 4000 cases/100 000 individuals. Before COVID-19, some vaccines were reported to cause myocarditis and pericarditis in rare cases, but the use of novel mRNA platforms led to a higher number of reported cases than with previous platforms providing new insight into potential pathogenic mechanisms. The incidence of COVID-19 vaccine-associated myocarditis/pericarditis covers a large range depending on the vaccine platform, age, and sex examined. Importantly, the findings highlight that myocarditis occurs predominantly in male patients aged 12 to 40 years regardless of whether the cause was due to a virus-like SARS-CoV-2 or associated with a vaccine-a demographic that has been reported before COVID-19. This review discusses findings from COVID-19 and COVID-19 vaccine-associated myocarditis and pericarditis considering the known symptoms, diagnosis, management, treatment, and pathogenesis of disease that has been gleaned from clinical research and animal models. Sex differences in the immune response to COVID-19 are discussed, and theories for how mRNA vaccines could lead to myocarditis/pericarditis are proposed. Additionally, gaps in our understanding that need further research are raised., Competing Interests: Disclosures D. Fairweather is on the advisory board of Cytokinetics. B. Heidecker is an inventor on patents that use RNA for diagnosis of myocarditis. L.T. Cooper has served as a consultant for myocarditis to Bristol Meyers Squibb, CardiolRx, Kiniksa, and Moderna. He has equity ownership in Stromal Therapeutics, Inc. The other authors report no conflicts.

Background: Idiopathic pulmonary fibrosis is responsible for 40,000 deaths annually in the United States. A hallmark of idiopathic pulmonary fibrosis is elevated collagen deposition, which alters lung stiffness. Clinically relevant ways to measure changes in lung stiffness during pulmonary fibrosis are not available, and new noninvasive imaging methods are needed to measure changes in lung mechanical properties., Objectives: Magnetic resonance elastography (MRE) is an in vivo magnetic resonance imaging technique proven to detect changes in shear stiffness in different organs. This study used MRE, histology, and bronchoalveolar lavage (BAL) to study changes in the mechanical and structural properties of the lungs after bleomycin-induced pulmonary fibrosis in pigs., Materials and Methods: Pulmonary fibrosis was induced in 9 Yorkshire pigs by intratracheal instillation of 2 doses of bleomycin into the right lung only. Magnetic resonance elastography scans were performed at baseline and week 4 and week 8 postsurgery in a 1.5 T magnetic resonance imaging scanner using a spin-echo echo planar imaging sequence to measure changes in lung shear stiffness. At the time of each scan, a BAL was performed. After the final scan, whole lung tissue was removed and analyzed for histological changes., Results: Mean MRE-derived stiffness measurements at baseline, week 4, and week 8 for the control (left) lungs were 1.02 ± 0.27 kPa, 0.86 ± 0.29 kPa, and 0.68 ± 0.20 kPa, respectively. The ratio of the shear stiffness in the injured (right) lung to the uninjured control (left) lung at baseline, week 4, and week 8 was 0.98 ± 0.23, 1.52 ± 0.41, and 1.64 ± 0.40, respectively. High-dose animals showed increased protein in BAL fluid, elevated inflammation observed by the presence of patchy filtrates, and enhanced collagen and α-smooth muscle actin staining on histological sections. Low-dose animals and the control (left) lungs of high-dose animals did not show significant histopathological changes., Conclusion: This study demonstrated that MRE can be used to detect changes in lung stiffness in pigs after bleomycin challenge., Competing Interests: Conflicts of interest and sources of funding: NIH-R01HL124096, R01AR075062, R01HL141217, and NCAI-18-11 and the President's Accelerator Award by The Ohio State University., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Background: The assessment of cardiac output (CO) is a major challenge during shock. The criterion standard for CO evaluation is transpulmonary thermodilution, which is an invasive technique. Speckle tracking is an automatized method of analyzing tissue motion using echography. This tool can be used to monitor pulsed arterial diameter variations with low interobserver variability. An experimental model of controlled hemorrhagic shock allows for multiple CO variations. The main aim of this study is to show the correlation between the femoral arterial diameter variations (fADVs) and the stroke volume (SV) measured by thermodilution during hemorrhagic shock management and the resuscitation of anesthetized piglets. The secondary objective is to explore the respective correlations between SV and subaortic time-velocity index, abdominal aorta ADV, carotid ADV, and subclavian ADV. Methods : Piglets were bled until mean arterial pressure reached 40 mm Hg. Controlled hemorrhage was maintained for 30 minutes before randomizing the piglets to three resuscitation groups-the fluid-filling group (reanimated with saline solution only), NEph group (norepinephrine + saline solution), and Eph group (epinephrin + saline solution). Speckle tracking, echocardiographic, and hemodynamic measures were performed at different stages of the protocol. Results : Thirteen piglets were recruited and included for statistical analysis. Of all the piglets, 164 fADV measures were attempted and 160 were successful (98%). The correlation coefficient between fADV and SV was 0.71 (95% confidence interval [CI], 0.62 to 0.78; P < 0.01). The correlation coefficient between SV and abdominal aorta ADV, subclavian ADV, and carotid ADV was 0.30 (95% CI, 0.13 to 0.46; P < 0.01), 0.56 (95% CI, 0.45 to 0.66, P < 0.01), and 0.15 (95% CI, -0.01 to 0.30, P = 0.06), respectively. Conclusions : In this hemorrhagic shock model using piglets, fADV was strongly correlated with SV., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by the Shock Society.)

The article focuses on the observational studies revealing the high risk of bleeding when single platelet therapy is combined with oral coagulation. It discusses the risk of ischemic and bleeding event in patients with concomitant stable coronary artery disease (CAD) and atrial fibrillation (AF), and the use of aspirin.