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The fabrication of complex and stable vasculature in engineered cardiac tissues represents a significant hurdle towards building physiologically relevant models of the heart. Here, we implemented a 3D model of cardiac vasculogenesis, incorporating endothelial cells (EC), stromal cells, and human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) in a fibrin hydrogel. The presence of CMs disrupted vessel formation in 3D tissues, resulting in the upregulation of endothelial activation markers and altered extracellular vesicle (EV) signaling in engineered tissues as determined by the proteomic analysis of culture supernatant. miRNA sequencing of CM- and EC-secreted EVs highlighted key EV-miRNAs that were postulated to play differing roles in cardiac vasculogenesis, including the let-7 family and miR-126-3p in EC-EVs. In the absence of CMs, the supplementation of CM-EVs to EC monolayers attenuated EC migration and proliferation and resulted in shorter and more discontinuous self-assembling vessels when applied to 3D vascular tissues. In contrast, supplementation of EC-EVs to the tissue culture media of 3D vascularized cardiac tissues mitigated some of the deleterious effects of CMs on vascular self-assembly, enhancing the average length and continuity of vessel tubes that formed in the presence of CMs. Direct transfection validated the effects of the key EC-EV miRNAs let-7b-5p and miR-126-3p in improving the maintenance of continuous vascular networks. EC-EV supplementation to biofabricated cardiac tissues and microfluidic devices resulted in tissue vascularization, illustrating the use of this approach in the engineering of enhanced, perfusable, microfluidic models of the myocardium., (Creative Commons Attribution license.)

The intricate anatomical structure and high cellular density of the myocardium complicate the bioengineering of perfusable vascular networks within cardiac tissues. In vivo neonatal studies highlight the key role of resident cardiac macrophages in post-injury regeneration and angiogenesis. Here, we integrate human pluripotent stem-cell-derived primitive yolk-sac-like macrophages within vascularized heart-on-chip platforms. Macrophage incorporation profoundly impacted the functionality and perfusability of microvascularized cardiac tissues up to 2 weeks of culture. Macrophages mitigated tissue cytotoxicity and the release of cell-free mitochondrial DNA (mtDNA), while upregulating the secretion of pro-angiogenic, matrix remodeling, and cardioprotective cytokines. Bulk RNA sequencing (RNA-seq) revealed an upregulation of cardiac maturation and angiogenesis genes. Further, single-nuclei RNA sequencing (snRNA-seq) and secretome data suggest that macrophages may prime stromal cells for vascular development by inducing insulin like growth factor binding protein 7 (IGFBP7) and hepatocyte growth factor (HGF) expression. Our results underscore the vital role of primitive macrophages in the long-term vascularization of cardiac tissues, offering insights for therapy and advancing heart-on-a-chip technologies., Competing Interests: Declaration of interests M.R. and Y.Z. are inventors on an issued patent that describes Biowire technology. This patent is licensed to Valo Health. M.R. and Y.Z. receive licensing revenue., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Epicardial cells (EPIs) form the outer layer of the heart and play an important role in development and disease. Current heart-on-a-chip platforms still do not fully mimic the native cardiac environment due to the absence of relevant cell types, such as EPIs. Here, using the Biowire II platform, engineered cardiac tissues with an epicardial outer layer and inner myocardial structure are constructed, and an image analysis approach is developed to track the EPI cell migration in a beating myocardial environment. Functional properties of EPI cardiac tissues improve over two weeks in culture. In conditions mimicking ischemia reperfusion injury (IRI), the EPI cardiac tissues experience less cell death and a lower impact on functional properties. EPI cell coverage is significantly reduced and more diffuse under normoxic conditions compared to the post-IRI conditions. Upon IRI, migration of EPI cells into the cardiac tissue interior is observed, with contributions to alpha smooth muscle actin positive cell population. Altogether, a novel heart-on-a-chip model is designed to incorporate EPIs through a formation process that mimics cardiac development, and this work demonstrates that EPI cardiac tissues respond to injury differently than epicardium-free controls, highlighting the importance of including EPIs in heart-on-a-chip constructs that aim to accurately mimic the cardiac environment., (© 2024 The Authors. Advanced Healthcare Materials published by Wiley‐VCH GmbH.)

Adverse cardiac outcomes in COVID-19 patients, particularly those with preexisting cardiac disease, motivate the development of human cell-based organ-on-a-chip models to recapitulate cardiac injury and dysfunction and for screening of cardioprotective therapeutics. Here, we developed a heart-on-a-chip model to study the pathogenesis of SARS-CoV-2 in healthy myocardium established from human induced pluripotent stem cell (iPSC)-derived cardiomyocytes and a cardiac dysfunction model, mimicking aspects of preexisting hypertensive disease induced by angiotensin II (Ang II). We recapitulated cytopathic features of SARS-CoV-2-induced cardiac damage, including progressively impaired contractile function and calcium handling, apoptosis, and sarcomere disarray. SARS-CoV-2 presence in Ang II-treated hearts-on-a-chip decreased contractile force with earlier onset of contractile dysfunction and profoundly enhanced inflammatory cytokines compared to SARS-CoV-2 alone. Toward the development of potential therapeutics, we evaluated the cardioprotective effects of extracellular vesicles (EVs) from human iPSC which alleviated the impairment of contractile force, decreased apoptosis, reduced the disruption of sarcomeric proteins, and enhanced beta-oxidation gene expression. Viral load was not affected by either Ang II or EV treatment. We identified MicroRNAs miR-20a-5p and miR-19a-3p as potential mediators of cardioprotective effects of these EVs., Competing Interests: Competing interests statement:Y.Z., G.V.-N., B.Z., and M.R. are inventors on patents for cardiac tissue cultivation that are licensed to Valo Health. Q.W., Y.Z., and M.R. have a filed patent application on thermoplastic polymer composition for micro 3D printing and uses thereof. B.Z. holds equity in OrganoBiotech.

Despite tremendous progress in the development of mature heart-on-a-chip models, human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip with circulating immune cells to model severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced acute myocarditis. We observed hallmarks of coronavirus disease (COVID-19)-induced myocardial inflammation, as the presence of immune cells augmented the secretion of proinflammatory cytokines, triggered progressive impairment of contractile function, and altered intracellular calcium transients. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the heart-on-a-chip and then validated in COVID-19 patients with low left ventricular ejection fraction, demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation-induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2-induced myocardial inflammation, we established that administration of endothelial cell-derived exosomes effectively rescued the contractile deficit, normalized calcium handling, elevated the contraction force, and reduced the ccf-mtDNA and cytokine release via Toll-like receptor-nuclear factor κB signaling axis.

Application of cardiac patches to the heart surface can be undertaken to provide support and facilitate regeneration of the damaged cardiac tissue following ischemic injury. Biomaterial composition is an important consideration in the design of cardiac patch materials as it governs host response to ultimately prevent the undesirable fibrotic response. Here, we investigate a novel patch material, poly (itaconate- co- citrate- co -octanediol) (PICO), in the context of cardiac implantation. Citric acid (CA) and itaconic acid (ITA), the molecular components of PICO, provided a level of protection for cardiac cells during ischemic reperfusion injury in vitro . Biofabricated PICO patches were shown to degrade in accelerated and hydrolytic conditions, with CA and ITA being released upon degradation. Furthermore, the host response to PICO patches after implantation on rat epicardium in vivo was explored and compared to two biocompatible cardiac patch materials, poly (octamethylene (anhydride) citrate) (POMaC) and poly (ethylene glycol) diacrylate (PEGDA). PICO patches resulted in less macrophage infiltration and lower foreign body giant cell reaction compared to the other materials, with corresponding reduction in smooth muscle actin-positive vessel infiltration into the implant region. Overall, this work demonstrates that PICO patches release CA and ITA upon degradation, both of which demonstrate cardioprotective effects on cardiac cells after ischemic injury, and that PICO patches generate a reduced inflammatory response upon implantation to the heart compared to other materials, signifying promise for use in cardiac patch applications., Competing Interests: LDH, MM and MR are coinventors on an issued US Patent "Biomaterial comprising poly(itaconate-co-citrate-co-octanediol)" Patent # 11,666,598)., (© 2023 The Authors.)

Background: Perioperative blood transfusions are associated with increased morbidity and mortality. Each surgical specialty is associated with unique operative variables. Moreover, transfusion rates vary across specialty. This article seeks to elucidate variables both common and unique to surgical specialties. Materials and Methods: This study was a retrospective review of 5344 patients from the prospectively maintained Veterans Affairs Surgical Quality Improvement Project at a single-level 1A tertiary Veterans Affairs Medical Center. Data collected included demographic information, preoperative clinical variables, postoperative outcomes, and perioperative transfusion (within 72 hours of procedure). Patients were stratified based on whether they received a transfusion. Univariate and multivariate analyses were performed. P values <.05 were significant. Results: Of the 5344 patients included in the study, 153 required perioperative transfusion of at least one unit of packed red blood cells. Patients who underwent transfusion were more likely to be men, have an underlying bleeding disorder, and have more preoperative risk factors. Although unique risk factors were found within most specialties, there was no statistically significant difference in postoperative complications between surgical specialties. Patients requiring transfusion had higher rates of morbidity and mortality. Elevated preoperative hematocrit was significantly protective against requiring transfusion across most specialties. Conclusions: Specialty-based differences in transfusion requirement may be due to the proportion of older and more frail patients, hospital transfusion thresholds, and surgical complexity. Hematocrit, however, could be an effective target for mitigating cost and morbidity associated with transfusion. Preoperative hematocrit optimization through B12, folate, iron dosing, and erythropoietin supplementation could be a useful strategy.

Objective: 20-40% of individuals whose seizures are not controlled by anti-seizure medications exhibit manifestations comparable to epileptic seizures (ES), but there are no EEG correlates. These events are called functional or dissociative seizures (FDS). Due to limited access to EEG-monitoring and inconclusive results, we aimed to develop an alternative diagnostic tool that distinguishes ES vs. FDS. We evaluated the temporal evolution of ECG-based measures of autonomic function (heart rate variability, HRV) to determine whether they distinguish ES vs. FDS., Methods: The prospective study includes patients admitted to the University of Rochester Epilepsy Monitoring Unit. Participants are 18-65 years old, without therapies or co-morbidities associated with altered autonomics. A habitual ES or FDS is recorded during admission. HRV analysis is performed to evaluate the temporal changes in autonomic function during the peri‑ictal period (150-minutes each pre-/post-ictal). We determined if autonomic measures distinguish ES vs. FDS., Results: The study includes 53 ES and 46 FDS. Temporal evolution of HR and autonomics significantly differ surrounding ES vs. FDS. The pre-to-post-ictal change (delta) in HR differs surrounding ES vs. FDS, stratified for convulsive and non-convulsive events. Post-ictal HR, total autonomic (SDNN & Total Power), vagal (RMSSD & HF), and baroreflex (LF) function differ for convulsive ES vs. convulsive FDS. HR distinguishes non-convulsive ES vs. non-convulsive FDS with ROC>0.7, sensitivity>70%, but specificity<50%. HR-delta and post-ictal HR, SDNN, RMSSD, LF, HF, and Total Power each distinguish convulsive ES vs. convulsive FDS (ROC, 0.83-0.98). Models with HR-delta and post-ictal HR provide the highest diagnostic accuracy for convulsive ES vs. convulsive FDS: 92% sensitivity, 94% specificity, ROC 0.99)., Significance: HR and HRV measures accurately distinguish convulsive, but not non-convulsive, events (ES vs. FDS). Results establish the framework for future studies to apply this diagnostic tool to more heterogeneous populations, and on out-of-hospital recordings, particularly for populations without access to epilepsy monitoring units., Competing Interests: Declaration of Competing Interest Justin M. Ryan reports no disclosures. Kyle T. Wagner reports no disclosures. Sushma Yerram reports no disclosures. Cathleen Concannon reports no disclosures. Jennifer X. Lin reports no disclosures. Patrick Rooney reports no disclosures. Brian Hanrahan reports no disclosures. Victoria Titoff reports no disclosures. Noreen L. Connolly reports no disclosures. Ramona Cranmer reports no disclosures. Natalia DeMaria reports no disclosures. Xiaojuan Xia reports no disclosures. Betty Mykins reports no disclosures. Steven Erickson reports no disclosures. Jean-Philippe Couderc reports no disclosures. Giovanni Schifitto reports no disclosures. Inna Hughes reports no disclosures. Dongliang Wang reports no disclosures. Giuseppe Erba reports no disclosures. David S. Auerbach reports no disclosures., (Copyright © 2023 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Background: Private sector literature demonstrates an association between perioperative transfusions and poor clinical outcomes. Hemostatic agents, surgeon training, and patient blood management programs (PBMPs) may mitigate perioperative bleeding. This study attempts to identify preoperative risk factors associated with perioperative transfusions in Veterans. Study Design and Methods: This study is a retrospective review of the prospectively maintained Veterans Affairs Surgical Quality Improvement Project database. Included patients were older than 18 years and underwent noncardiac surgery between April 1, 2016, and March 31, 2021. Data collected included demographics, surgery variables, preoperative clinical variables, postoperative outcomes, and perioperative transfusions. Cohorts were created based on transfusion status. Univariate and multivariate analyses were performed to characterize the similarities, differences, and potential predictors of perioperative transfusion. Results: Of 6108 patients included, 153 patients received perioperative transfusions. The risks for transfusion included older age, male sex, black race, smoking, and low body mass index (BMI). The highest percent of transfused patients underwent vascular (43.4%), orthopedic (22%), and general surgeries (20%). Transfusion increased risk for postoperative cerebral vascular accident ( P  = .041) and 30-day mortality ( P  < .001). Multivariate regression analysis revealed American Society of Anesthesiology class, chemotherapy within 30 days, increased age, tobacco smoking, and decreased BMI were predictive of perioperative transfusions. Discussion: Perioperative transfusions are associated with increased morbidity and mortality in the Veteran population. These retrospective data describe the complex relationships between perioperative transfusions and outcomes after noncardiac surgery. These results serve as a foundation to create predictive models and PBMP within the veteran population to decrease transfusion requirements and associated complications.

Purpose: The underlying mechanism for radiation as a potentiator of immune checkpoint inhibition (ICI) is unclear. We developed a novel murine model to investigate the effects of post-irradiation intratumoral heterogeneity (ITH) on response to ICI., Experimental Design: Parental mouse melanoma B16F10 cells were irradiated in vitro (5Gy x 3 fractions), then an a priori determined number of resulting colonies were implanted in C57BL/6J immunocompetent mice creating syngeneic models of unirradiated (parental) and irradiated tumors with low (irradiated-L) and high (irradiated-H) ITH. Mice were treated with placebo, α-PD-L1, α-CTLA-4 or dual ICI. Murine tumors underwent whole exome sequencing (WES). Clinically correlated paired pre- and post-irradiation patient rectal adenocarcinoma samples underwent WES., Results: Irradiated-L tumors showed increased tumor mutational burden (TMB) and a sustained decrease in ITH. Irradiated-L tumors were predicted to express five neoantigens with high variant allele frequency/clonal distribution. Mice with irradiated-L and irradiated-H versus parental B16F10 tumors demonstrated longer overall survival with dual ICI. Only mice with irradiated-L tumors experienced an overall survival benefit with single agent ICI. Clinically correlated rectal adenocarcinoma samples showed similarly increased TMB and decreased ITH following irradiation., Conclusions: Post-irradiation ITH modulates ICI response in a murine melanoma model. Irradiation may offer a mechanism to widen the therapeutic window of ICI., Competing Interests: Declaration of Competing Interest The authors declare no relevant conflict of interest. Full disclosures are provided. TZ has received research funding to institution from Acerta Pharma, Astellas Pharma, Janssen, Merrimack, Merck, Mirati Therapeutics, Novartis, OmniSeq, Personal Genome Diagnostics, Pfizer, Regeneron, StemCentRx; consulting or advisory roles at Amgen, AstraZeneca, Bristol-Myers Squibb, Calithera Biosciences, Dendreon, Exelixis, Foundation Medicine, Genentech/Roche, Janssen, Pharmacyclics, Pfizer, Sanofi, SeaGen, and QED Therapeutics; Honoraria from Exelixis, Genentech/Roche, MJH Life Science, Pacific Genuity; speaker's bureau at Genomic Health and Sanofi/Aventis; stock and other ownership interests at Archimmune Therapeutics (immediate family member), Capio Biosciences (immediate family member), and Nanorobotics (immediate family member). AZW has received research funding from Varian and is a cofounder of Archimmune Therapeutics and Capio Sciences. He also serves on the scientific board of Nanorobotics., (Copyright © 2022. Published by Elsevier Inc.)

By providing an ideal environment for healing, biomaterials can be designed to facilitate and encourage wound regeneration. As the wound healing process is complex, there needs to be consideration for the cell types playing major roles, such as fibroblasts. As a major cell type in the dermis, fibroblasts have a large impact on the processes and outcomes of wound healing. Prevopisly, conjugating the angiopoietin-1 derived Q-peptide (QHREDGS) to a collagen-chitosan hydrogel created a biomaterial with in vivo success in accelerating wound healing. This study utilized solvent cast Q-peptide conjugated collagen-chitosan seeded with fibroblast monolayers to investigate the direct impact of the material on this major cell type. After 24 h, fibroblasts had a significant change in release of anti-inflammatory, pro-healing, and ECM deposition cytokines, with demonstrated immunomodulatory effects on macrophages and upregulated expression of critical wound healing genes., Competing Interests: M.R. is a founder of Quthero Inc, holds equity in the company, receives consulting fees from the company and is a member of its Board of Directors. S.M. holds equity in Quthero Inc. M.R. and S.M. are inventors of patents licensed by Quthero Inc and they receive royalty payments from those patents., (© 2023 The Authors.)

Surgery is an important treatment for cancer; however, local recurrence following macroscopically-complete resection is common and a significant cause of morbidity and mortality. Systemic chemotherapy is often employed as an adjuvant therapy to prevent recurrence of residual disease, but has limited efficacy due to poor penetration and dose-limiting off-target toxicities. Selective delivery of chemotherapeutics to the surgical bed may eliminate residual tumor cells while avoiding systemic toxicity. While this is challenging for traditional drug delivery technologies, we utilized advances in 3D printing and drug delivery science to engineer a drug-loaded arrowhead array device (AAD) to overcome these challenges. We demonstrated that such a device can be designed, fabricated, and implanted intraoperatively and provide extended release of chemotherapeutics directly to the resection area. Using paclitaxel and cisplatin as model drugs and murine models of cancer, we showed AADs significantly decreased local recurrence post-surgery and improved survival. We further demonstrated the potential for fabricating personalized AADs for intraoperative application in the clinical setting., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Introduction: Methamphetamine use and methamphetamine-involved deaths have increased dramatically since 2015, and opioid-related deaths now frequently involve methamphetamine. Nevada and New Mexico are states with elevated rates of opioid and methamphetamine use. In this paper, we report results from a qualitative analysis that examined patterns of methamphetamine and opioid co-use over participants' lifespan, factors that influence those patterns, and implications for health outcomes among users., Methods: Project AMPED was a multisite, mixed-methods study of methamphetamine use in Northern New Mexico and Northern Nevada. Between December 2019 and May 2020, qualitative interview participants were asked to describe their patterns of and reasons for co-administration of opioids and methamphetamine., Results: We interviewed 21 people who reported using methamphetamine in the past 3 months. Four primary patterns of methamphetamine and opioid co-use were identified: [1] using both methamphetamine and heroin, either simultaneously or sequentially ( n = 12), [2] using methamphetamine along with methadone ( n = 4), [3] using prescription opioids and methamphetamine ( n = 1), and [4] using only methamphetamine ( n = 4). Among those who used methamphetamine and heroin simultaneously or sequentially, motivations drew from a desire to enhance the effect of one drug or another, to feel the "up and down" of the "perfect ratio" of a goofball, or to mitigate unwanted effects of one or the other. Among those who used methamphetamine and methadone, motivations focused on alleviating the sedative effects of methadone., Conclusion: To address the emergent trend of increasing methamphetamine-related deaths, researchers, health care professionals, and community health workers must acknowledge the decision-making processes behind co-use of opioids and methamphetamine, including the perceived benefits and harms of co-use. There is an urgent need to address underlying issues associated with drug use-related harms, and to design interventions and models of treatment that holistically address participants' concerns., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rhed, Harding, Marks, Wagner, Fiuty, Page and Wagner.)

Introduction: Sleeve gastrectomy engenders weight loss and improves comorbidities at 1 year postoperatively. A relationship has not been established between liver pathology and diabetic outcomes and weight loss following a sleeve gastrectomy. This study evaluates the association between liver pathology and both diabetic remission and weight loss in morbidly obese veterans. Methods: A prospective database of all patients undergoing sleeve gastrectomy with simultaneous liver biopsy at a Veterans Affairs Medical Center was analyzed from 2018 through 2020. The database included patient demographics, liver biopsy pathology, laboratory values, and antihyperglycemic medications. Patient outcomes at 12 months postoperatively were analyzed specifically for diabetic resolution and weight loss. Chi-square test and Fisher's exact test were used for categorical comparisons, and one-way analysis of variance test and two-tailed t -test were used for continuous variable comparisons. Multivariate linear regression models were created to assess the association between liver pathology and changes in body mass index (BMI) and diabetic status. A two-sided P -value of 0.05 indicated significance. Results: Of the 77 patients included in the study, 70.1% of patients achieved diabetic remission at 12 months. After condensing steatosis and fibrosis scores into low- and high-grade categories, patients with no hepatic disease had significantly lower BMI at 12 months postoperatively than patients with low- or high-grade hepatic disease (29.2 ± 3.6 kg/m 2 versus 35.1 ± 4.0 kg/m 2 versus 34.5 ± 3.7 kg/m 2 , respectively, P  = .009). On multivariate linear regression model, low-grade overall hepatic disease (β = 3.1 ± 1.5; P  = .043) and preoperative oral glycemic medications (β = 2.4 ± 1.0; P  = .026) were associated with a significantly increased 12-month BMI. Also, Black or African American race compared with White race was associated with a significant decrease in postoperative BMI (β = -1.9 ± 0.8; P  = .023). Conclusions: Regardless of preexisting liver disease, most diabetic patients who undergo sleeve gastrectomy experience diabetic remission at 12 months postoperatively. Additionally, patients with no underlying liver disease lose more weight than those with low- or high-grade liver disease.

Background: Management of symptomatic pancreatic pseudocysts poses a unique challenge to minimally invasive surgeons. Despite the predominance of endoscopic management of pancreatic pseudocysts, the laparoscopic approach remains a critical skill in the armamentarium of surgeons. Methods: This report details a laparoscopic intragastric approach to create a pancreatic cystgastrostomy using intraoperative ultrasound and endoscopy. Conclusion: Laparoendoscopic techniques for pancreatic pseudocysts are still required in selective cases when endoscopic management is not available or fails. Using this technique provides patients with same clinical benefits of an endoscopic approach.

Background: The USA is experiencing increases in methamphetamine use and methamphetamine-related or attributed deaths. In the current study, we explore qualitative narratives of methamphetamine overdose and strategies used by people who use drugs to reduce the undesirable effects associated with methamphetamine use., Methods: We conducted 21 qualitative interviews with people over the age of 18 who reported using methamphetamine in the previous 3 months in Nevada and New Mexico. Interviews were recorded, transcribed, and analyzed using qualitative thematic analysis., Results: Respondents described a constellation of psychological and physical symptoms that they characterized as "overamping," experienced on a continuum from less to more severe. Reports of acute, fatal methamphetamine overdose were rare. Few reported seeking medical attention for undesirable effects (usually related to psychological effects). General self-care strategies such as sleeping and staying hydrated were discussed., Conclusions: When asked directly, our respondents claimed that acute, fatal methamphetamine overdose is rare or even impossible. However, they described a number of undesirable symptoms associated with overconsumption of methamphetamine and had few clinical or harm reduction strategies at their disposal. Addressing this current wave of drug-related deaths will require attention to the multiple factors that structure experiences of methamphetamine "overdose," and a collaborative effort with PWUDs to devise effective harm reduction and treatment strategies., (© 2022. The Author(s).)

Cardiovascular diseases are the leading cause of death worldwide. Discovering new therapies to treat heart disease requires improved understanding of cardiac physiology at a cellular level. Extracellular vesicles (EVs) are plasma membrane-bound nano- and microparticles secreted by cells and known to play key roles in intercellular communication, often through transfer of biomolecular cargo. Advances in EV research have established techniques for EV isolation from tissue culture media or biofluids, as well as standards for quantitation and biomolecular characterization. EVs released by cardiac cells are known to be involved in regulating cardiac physiology as well as in the progression of myocardial diseases. Due to difficulty accessing the heart in vivo, advanced in vitro cardiac 'tissues-on-a-chip' have become a recent focus for studying EVs in the heart. These physiologically relevant models are producing new insight into the role of EVs in cardiac physiology and disease while providing a useful platform for screening novel EV-based therapeutics for cardiac tissue regeneration post-injury. Numerous hurdles have stalled the clinical translation of EV therapeutics for heart patients, but tissue-on-a-chip models are playing an important role in bridging the translational gap, improving mechanistic understanding of EV signalling in cardiac physiology, disease, and repair., Competing Interests: Conflict of Interest The authors declare no conflict of interest.

Extracellular matrix bioscaffolds can influence the cardiac microenvironment and modulate endogenous cellular mechanisms. These materials can optimize cardiac surgery for repair and reconstruction. We investigated the biocompatibility and bioinductivity of bovine pericardium fixed via dye-mediated photo-oxidation on human cardiac fibroblast activity. We compared a dye-mediated photo-oxidation fixed bioscaffold to glutaraldehyde-fixed and non-fixed bioscaffolds reported in contemporary literature in cardiac surgery. Human cardiac fibroblasts from consenting patients were seeded on to bioscaffold materials to assess the biocompatibility and bioinductivity. Human cardiac fibroblast gene expression, secretome, morphology and viability were studied. Dye-mediated photo-oxidation fixed acellular bovine pericardium preserves human cardiac fibroblast phenotype and viability; and potentiates a pro-vasculogenic paracrine response. Material tensile properties were compared with biomechanical testing. Dye-mediated photo-oxidation fixed acellular bovine pericardium had higher compliance compared to glutaraldehyde-fixed bioscaffold in response to tensile force. The biocompatibility, bioinductivity, and biomechanical properties of dye-mediated photo-oxidation fixed bovine pericardium demonstrate its feasibility as a bioscaffold for use in cardiac surgery. As a fixed yet bioinductive solution, this bioscaffold demonstrates enhanced compliance and retains bioinductive properties that may leverage endogenous reparative pathways. Dye-mediated photo-oxidation fixed bioscaffold warrants further investigation as a viable tool for cardiac repair and reconstruction.

Strategies to regenerate cardiac tissue postinjury are limited and heart transplantation remains the only 'cure' for a failing heart. Extracellular vesicles (EVs), membrane-bound cell secretions important in intercellular signaling, have been shown to play a crucial role in regulating heart function. A mechanistic understanding of the role of EVs in the heart remains elusive due to the challenges in studying the native human heart. Tissue-on-a-chip platforms, comprising functional, physiologically relevant human tissue models, are an emerging technology that has yet to be fully applied to the study of EVs. In this review, we summarize recent advances in cardiac tissue-on-a-chip (CTC) platforms and discuss how they are uniquely situated to advance our understanding of EVs in cardiac disease and regeneration., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Polyps in the upper and lower gastrointestinal tract can be premalignant or malignant lesions that can be treated endoscopically in early stages to prevent morbidity and more invasive procedures. This article critically reviews the techniques available and provides recommendations for endoscopic polypectomy., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Coronary heart disease is a leading cause of death. Tissue remodeling and fibrosis results in cardiac pump dysfunction and ischemic heart failure. Cardiac fibroblasts may rebuild damaged tissues when prompted by suitable environmental cues. Here, we use acellular biologic extracellular matrix scaffolds (bioscaffolds) to stimulate pathways of muscle repair and restore tissue function. We show that acellular bioscaffolds with bioinductive properties can redirect cardiac fibroblasts to rebuild microvascular networks and avoid tissue fibrosis. Specifically, when human cardiac fibroblasts are combined with bioactive scaffolds, gene expression is upregulated and paracrine mediators are released that promote vasculogenesis and prevent scarring. We assess these properties in rodents with myocardial infarction and observe bioscaffolds to redirect fibroblasts, reduce tissue fibrosis and prevent maladaptive structural remodeling. Our preclinical data confirms that acellular bioscaffold therapy provides an appropriate microenvironment to stimulate pathways of functional repair. We translate our observations to patients with coronary heart disease by conducting a first-in-human observational cohort study. We show that bioscaffold therapy is associated with improved perfusion of infarcted myocardium, reduced myocardial scar burden, and reverse structural remodeling. We establish that clinical use of acellular bioscaffolds is feasible and offers a new frontier to enhance surgical revascularization of ischemic heart muscle.

Nanoparticle (NP) chemotherapeutics can improve the therapeutic index of chemoradiotherapy (CRT). However, the effect of NP physical properties, such particle size, on CRT is unknown. To address this, we examined the effects of NP size on biodistribution, efficacy and toxicity in CRT. PEG-PLGA NPs (50, 100, 150 nm mean diameters) encapsulating wotrmannin (wtmn) or KU50019 were formulated. These NP formulations were potent radiosensitizers in vitro in HT29, SW480, and lovo rectal cancer lines. In vivo, the smallest particles avoided hepatic and splenic accumulation while more homogeneously penetrating tumor xenografts than larger particles. However, smaller particles were no more effective in vivo. Instead, there was a trend toward enhanced efficacy with medium sized NPs. The smallest KU60019 particles caused more small bowel toxicity than larger particles. Our results showed that particle size significantly affects nanotherapeutics' biodistrubtion and toxicity but does not support the conclusion that smaller particles are better for this clinical application., (Published by Elsevier Inc.)

The combination chemotherapy regimen of cisplatin (CP) and docetaxel (DTX) is effective against a variety of cancers. However, combination therapies present unique challenges that can complicate clinical application, such as increases in toxicity and imprecise exposure of tumors to specific drug ratios that can produce treatment resistance. Drug co-encapsulation within a single nanoparticle (NP) formulation can overcome these challenges and further improve combinations' therapeutic index. In this report, we employ a CP prodrug (CPP) strategy to formulate poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) NPs carrying both CPP and DTX. The dually loaded NPs display differences in drug release kinetics and in vitro cytotoxicity based on the structure of the chosen CPP. Furthermore, NPs containing both drugs showed a significant improvement in treatment efficacy versus the free drug combination in vivo., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: To examine the effect of radiation on in vitro drug activation and release of Promitil, a pegylated liposomal formulation of a mitomycin C (MMC) lipid-based prodrug; and examine the efficacy and toxicity of Promitil with concurrent radiation in colorectal cancer models., Methods and Materials: Promitil was obtained from Lipomedix Pharmaceuticals (Jerusalem, Israel). We tested the effects of radiation on release of active MMC from Promitil in vitro. We next examined the radiosensitization effect of Promitil in vitro. We further evaluated the toxicity of a single injection of free MMC or Promitil when combined with radiation by assessing the effects on blood counts and in-field skin and hair toxicity. Finally, we compared the efficacy of MMC and Promitil in chemoradiotherapy using mouse xenograft models., Results: Mitomycin C was activated and released from Promitil in a controlled-release profile, and the rate of release was significantly increased in medium from previously irradiated cells. Both Promitil and MMC potently radiosensitized HT-29 cells in vitro. Toxicity of MMC (8.4 mg/kg) was substantially greater than with equivalent doses of Promitil (30 mg/kg). Mice treated with human-equivalent doses of MMC (3.3 mg/kg) experienced comparable levels of toxicity as Promitil-treated mice at 30 mg/kg. Promitil improved the antitumor efficacy of 5-fluorouracil-based chemoradiotherapy in mouse xenograft models of colorectal cancer, while equitoxic doses of MMC did not., Conclusions: We demonstrated that Promitil is an attractive agent for chemoradiotherapy because it demonstrates a radiation-triggered release of active drug. We further demonstrated that Promitil is a well-tolerated and potent radiosensitizer at doses not achievable with free MMC. These results support clinical investigations using Promitil in chemoradiotherapy., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Radiotherapy is a key component of cancer treatment. Because of its importance, there has been high interest in developing agents and strategies to further improve the therapeutic index of radiotherapy. DNA double-strand repair inhibitors (DSBRIs) are among the most promising agents to improve radiotherapy. However, their clinical translation has been limited by their potential toxicity to normal tissue. Recent advances in nanomedicine offer an opportunity to overcome this limitation. In this study, we aim to demonstrate the proof of principle by developing and evaluating nanoparticle (NP) formulations of KU55933, a DSBRI. We engineered a NP formulation of KU55933 using nanoprecipitation method with different lipid polymer nanoparticle formulation. NP KU55933 using PLGA formulation has the best loading efficacy as well as prolonged drug release profile. We demonstrated that NP KU55933 is a potent radiosensitizer in vitro using clonogenic assay and is more effective as a radiosensitizer than free KU55933 in vivo using mouse xenograft models of non-small cell lung cancer (NSCLC). Western blots and immunofluorescence showed NP KU55933 exhibited more prolonged inhibition of DNA repair pathway. In addition, NP KU55933 leads to lower skin toxicity than KU55933. Our study supports further investigations using NP to deliver DSBRIs to improve cancer radiotherapy treatment.

Histone deacetylase inhibitors (HDACIs) represent a class of promising agents that can improve radiotherapy in cancer treatment. However, the full therapeutic potential of HDACIs as radiosensitizers has been restricted by limited efficacy in solid malignancies. In this study, we report the development of nanoparticle (NP) formulations of HDACIs that overcome these limitations, illustrating their utility to improve the therapeutic ratio of the clinically established first generation HDACI vorinostat and a novel second generation HDACI quisinostat. We demonstrate that NP HDACIs are potent radiosensitizers in vitro and are more effective as radiosensitizers than small molecule HDACIs in vivo using mouse xenograft models of colorectal and prostate carcinomas. We found that NP HDACIs enhance the response of tumor cells to radiation through the prolongation of γ-H2AX foci. Our work illustrates an effective method for improving cancer radiotherapy treatment., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Chemosensitizers can improve the therapeutic index of chemotherapy and overcome treatment resistance. Successful translation of chemosensitizers depends on the development of strategies that can preferentially deliver chemosensitizers to tumors while avoiding normal tissue. We hypothesized that nanoparticle (NP) formulation of chemosensitizers can improve their delivery to tumors which can in turn improve their therapeutic index. To demonstrate the proof of principle of this approach, we engineered NP formulations of two chemosensitizers, the PI3-kindase inhibitor wortmanin (Wtmn) and the PARP inhibitor olaparib. NP Wtmn and NP olaparib were evaluated as chemosensitizers using lung cancer cells and breast cancer cells respectively. We found Wtmn to be an efficient chemosensitizer in all tested lung-cancer cell lines reducing tumor cell growth between 20 and 60% compared to drug alone. NP formulation did not decrease its efficacy in vitro. Olaparib showed less consistent chemosensitization as a free drug or in NP formulation. NP Wtmn was further evaluated as a chemosensitizer using mouse models of lung cancer. We found that NP Wtmn is an effective chemosensitizer and more effective than free Wtmn showing a 32% reduction in tumor growth compared to free Wtmn when given with etoposide. Importantly, NP Wtmn was able to sensitize the multi-drug resistant H69AR cells to etoposide. Additionally, the combination of NP Wtmn and etoposide chemotherapy did not significantly increase toxicity. The present study demonstrates the proof of principle of using NP formulation of chemosensitizing drugs to improve the therapeutic index of chemotherapy.

Phenylalanine hydroxylase (PAH) is a non-heme iron enzyme that catalyzes oxidation of phenylalanine to tyrosine, a reaction that must be kept under tight regulatory control. Mammalian PAH has a regulatory domain in which binding of the substrate leads to allosteric activation of the enzyme. However, the existence of PAH regulation in evolutionarily distant organisms, for example some bacteria in which it occurs, has so far been underappreciated. In an attempt to crystallographically characterize substrate binding by PAH from Chromobacterium violaceum, a single-domain monomeric enzyme, electron density for phenylalanine was observed at a distal site 15.7 Å from the active site. Isothermal titration calorimetry (ITC) experiments revealed a dissociation constant of 24 ± 1.1 μM for phenylalanine. Under the same conditions, ITC revealed no detectable binding for alanine, tyrosine, or isoleucine, indicating the distal site may be selective for phenylalanine. Point mutations of amino acid residues in the distal site that contact phenylalanine (F258A, Y155A, T254A) led to impaired binding, consistent with the presence of distal site binding in solution. Although kinetic analysis revealed that the distal site mutants suffer discernible loss of their catalytic activity, X-ray crystallographic analysis of Y155A and F258A, the two mutants with the most noticeable decrease in activity, revealed no discernible change in the structure of their active sites, suggesting that the effect of distal binding may result from protein dynamics in solution.

Human papillomavirus causes anal condylomata, high-grade anal intraepithelial neoplasia, and anal squamous cell cancer. We found high-grade intraepithelial neoplasia or squamous cell cancer in 75 (47%) of 159 HIV-seropositive men who have sex with men (MSM) and in 42 (26%) of 160 HIV-seronegative MSM with anal condylomata meriting surgery (P<.001, determined by use of the chi(2) test). Anal condylomata in MSM often harbor high-grade intraepithelial neoplasia and squamous cell cancer.

Nine of 212 cases of traumatic anterior shoulder dislocations occurred in children with clearly open epiphyses (4.7% incidence). All cases associated with psychological or physical abnormalities were excluded. A high recurrence rate of 80% (8 of 10) was noted requiring operative intervention. Two of the three remaining unoperated cases had a history of "subluxation" after their initial dislocation.