Sterilization of lung matrices by supercritical carbon dioxide

Lung engineering is a potential alternative to transplantation for patients with end-stage pulmonary failure. Two challenges critical to the successful development of an engineered lung developed from a decellularized scaffold include (i) the suppression of resident infectious bioburden in the lung matrix, and (ii) the ability to sterilize decellularized tissues while preserving the essential biological and mechanical features intact. To date, the majority of lungs are sterilized using high concentrations of peracetic acid (PAA) resulting in extracellular matrix (ECM) depletion. These mechanically altered tissues have little to no storage potential. In this study, we report a sterilizing technique using supercritical carbon dioxide (ScCO(2)) that can achieve a sterility assurance level 10(−6) in decellularized lung matrix. The effects of ScCO(2) treatment on the histological, mechanical, and biochemical properties of the sterile decellularized lung were evaluated and compared with those of freshly decellularized lung matrix and with PAA-treated acellular lung. Exposure of the decellularized tissue to ScCO(2) did not significantly alter tissue architecture, ECM content or organization (glycosaminoglycans, elastin, collagen, and laminin), observations of cell engraftment, or mechanical integrity of the tissue. Furthermore, these attributes of lung matrix did not change after 6 months in sterile buffer following sterilization with ScCO(2), indicating that ScCO(2) produces a matrix that is stable during storage. The current study's results indicate that ScCO(2) can be used to sterilize acellular lung tissue while simultaneously preserving key biological components required for the function of the scaffold for regenerative medicine purposes

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Substratum Interactions Modulate the Interplay between Endothelial Cell Phenotype, Function, and Immune Recognition

Endothelial cells (ECs) sense and adapt to their environment, allowing them to shift between a range of functional phenotypes. When connected in a monolayer they create the endothelium, a barrier and a platform from which ECs can individually respond to flow, and circulating cells and factors apically, cell density circumferentially, and substratum composition, stiffness, and texture basolaterally. Plasticity allows ECs to promote vascular homeostasis, and to interact with and modulate the immune system. Changes in endothelial state enable immune cells to migrate into the tissue to repair tissue damage and fight infection. However, the ECs also modulate the function of immune cells through the expression of adhesion molecules, chemokines, major histocompatibility complex (MHC), and an array of co-stimulatory and inhibitor molecules. These interactions allow ECs to act as antigen presenting cells (APCs) and influence the outcome of immune recognition. Thus, the study of ECs elucidates how microenvironment, vascular cell biology, and immune response are not only connected but interdependent. This work explored how cell-substratum interactions influence EC phenotype and function and how these differences affect allorecognition in a model of cell transplantation. Investigation of EC state was carried out using RNA sequencing and flow cytometry while assessment of the allogeneic response included measurements of immune cell cytotoxic ability, T cell proliferation, cytokine release, serum antibodies, and histological staining. We found that differences in substratum led to divergent EC phenotypes which in turn influenced immune response to transplanted cells, both due to the physical barrier of matrix-adhesion and differences in gene expression.Ph.D

Effectiveness of teen Mental Health First Aid in Improving Teen-to-Teen Support Among American Adolescents

BACKGROUND: teen Mental Health First Aid (tMHFA) is an Australian school-based universal program for grade 10 to 12 students. tMHFA teaches teens how to recognize and respond to a peer in crisis or experiencing mental health concerns. METHODS: Schools implementing tMHFA in 2019 and 2020 were propensity score matched, yielding a sample of instructors (n = 130) and students (n = 1915) in 44 high schools in 24 American states. Effectiveness and acceptability were assessed with student surveys at baseline and after implementation. RESULTS: There were significant findings for primary outcomes, including improved helpful first aid intentions (Cohen ds = 0.57 to 0.58), confidence supporting a peer (ds = 0.19 to 0.31); the number of adults rated as helpful (ds = 0.37 to 0.44); and reductions in stigmatizing beliefs (ds = 0.21 to 0.40) and harmful first aid intentions (ds = 0.11 to 0.42). Instructors and students rated the program favorably with students sharing improvements on their recognition and responses to mental health problems and crises. CONCLUSION: tMHFA is an effective, feasible, and scalable training program for increasing mental health literacy and decreasing mental health stigma in adolescents in the short term, consistent with trials of tMHFA in Australian adolescents