Inflammation-induced subcutaneous neovascularization for the long-term survival of encapsulated islets without immunosuppression.

Cellular therapies for type-1 diabetes can leverage cell encapsulation to dispense with immunosuppression. However, encapsulated islet cells do not survive long, particularly when implanted in poorly vascularized subcutaneous sites. Here we show that the induction of neovascularization via temporary controlled inflammation through the implantation of a nylon catheter can be used to create a subcutaneous cavity that supports the transplantation and optimal function of a geometrically matching islet-encapsulation device consisting of a twisted nylon surgical thread coated with an islet-seeded alginate hydrogel. The neovascularized cavity led to the sustained reversal of diabetes, as we show in immunocompetent syngeneic, allogeneic and xenogeneic mouse models of diabetes, owing to increased oxygenation, physiological glucose responsiveness and islet survival, as indicated by a computational model of mass transport. The cavity also allowed for the in situ replacement of impaired devices, with prompt return to normoglycemia. Controlled inflammation-induced neovascularization is a scalable approach, as we show with a minipig model, and may facilitate the clinical translation of immunosuppression-free subcutaneous islet transplantation.

AT7867 promotes pancreatic progenitor differentiation of human iPSCs.

Generation of pure pancreatic progenitor (PP) cells is critical for clinical translation of stem cell-derived islets. Herein, we performed PP differentiation with and without AKT/P70 inhibitor AT7867 and characterized the resulting cells at protein and transcript level in vitro and in vivo upon transplantation into diabetic mice. AT7867 treatment increased the percentage of PDX1+NKX6.1+ (-AT7867: 50.9% [IQR 48.9%-53.8%]; +AT7867: 90.8% [IQR 88.9%-93.7%]; p = 0.0021) and PDX1+GP2+ PP cells (-AT7867: 39.22% [IQR 36.7%-44.1%]; +AT7867: 90.0% [IQR 88.2%-93.6%]; p = 0.0021). Transcriptionally, AT7867 treatment significantly upregulated PDX1 (p = 0.0001), NKX6.1 (p = 0.0005), and GP2 (p = 0.002) expression compared with controls, while off-target markers PODXL (p < 0.0001) and TBX2 (p < 0.0001) were significantly downregulated. Transplantation of AT7867-treated PPs resulted in faster hyperglycemia reversal in diabetic mice compared with controls (time and group: p < 0.0001). Overall, our data show that AT7867 enhances PP cell differentiation leading to accelerated diabetes reversal.

Mitochondrial regulation in human pluripotent stem cells during reprogramming and ß cell differentiation.

Mitochondria are the powerhouse of the cell and dynamically control fundamental biological processes including cell reprogramming, pluripotency, and lineage specification. Although remarkable progress in induced pluripotent stem cell (iPSC)-derived cell therapies has been made, very little is known about the role of mitochondria and the mechanisms involved in somatic cell reprogramming into iPSC and directed reprogramming of iPSCs in terminally differentiated cells. Reprogramming requires changes in cellular characteristics, genomic and epigenetic regulation, as well as major mitochondrial metabolic changes to sustain iPSC self-renewal, pluripotency, and proliferation. Differentiation of autologous iPSC into terminally differentiated ß-like cells requires further metabolic adaptation. Many studies have characterized these alterations in signaling pathways required for the generation and differentiation of iPSC; however, very little is known regarding the metabolic shifts that govern pluripotency transition to tissue-specific lineage differentiation. Understanding such metabolic transitions and how to modulate them is essential for the optimization of differentiation processes to ensure safe iPSC-derived cell therapies. In this review, we summarize the current understanding of mitochondrial metabolism during somatic cell reprogramming to iPSCs and the metabolic shift that occurs during directed differentiation into pancreatic ß-like cells.

Suspension culture improves iPSC expansion and pluripotency phenotype.

BACKGROUND: Induced pluripotent stem cells (iPSCs) offer potential to revolutionize regenerative medicine as a renewable source for islets, dopaminergic neurons, retinal cells, and cardiomyocytes. However, translation of these regenerative cell therapies requires cost-efficient mass manufacturing of high-quality human iPSCs. This study presents an improved three-dimensional Vertical-Wheel® bioreactor (3D suspension) cell expansion protocol with comparison to a two-dimensional (2D planar) protocol. METHODS: Sendai virus transfection of human peripheral blood mononuclear cells was used to establish mycoplasma and virus free iPSC lines without common genetic duplications or deletions. iPSCs were then expanded under 2D planar and 3D suspension culture conditions. We comparatively evaluated cell expansion capacity, genetic integrity, pluripotency phenotype, and in vitro and in vivo pluripotency potential of iPSCs. RESULTS: Expansion of iPSCs using Vertical-Wheel® bioreactors achieved 93.8-fold (IQR 30.2) growth compared to 19.1 (IQR 4.0) in 2D (p < 0.0022), the largest expansion potential reported to date over 5 days. 0.5 L Vertical-Wheel® bioreactors achieved similar expansion and further reduced iPSC production cost. 3D suspension expanded cells had increased proliferation, measured as Ki67+ expression using flow cytometry (3D: 69.4% [IQR 5.5%] vs. 2D: 57.4% [IQR 10.9%], p = 0.0022), and had a higher frequency of pluripotency marker (Oct4+Nanog+Sox2+) expression (3D: 94.3 [IQR 1.4] vs. 2D: 52.5% [IQR 5.6], p = 0.0079). q-PCR genetic analysis demonstrated a lack of duplications or deletions at the 8 most commonly mutated regions within iPSC lines after long-term passaging (> 25). 2D-cultured cells displayed a primed pluripotency phenotype, which transitioned to naïve after 3D-culture. Both 2D and 3D cells were capable of trilineage differentiation and following teratoma, 2D-expanded cells generated predominantly solid teratomas, while 3D-expanded cells produced more mature and predominantly cystic teratomas with lower Ki67+ expression within teratomas (3D: 16.7% [IQR 3.2%] vs.. 2D: 45.3% [IQR 3.0%], p = 0.002) in keeping with a naïve phenotype. CONCLUSION: This study demonstrates nearly 100-fold iPSC expansion over 5-days using our 3D suspension culture protocol in Vertical-Wheel® bioreactors, the largest cell growth reported to date. 3D expanded cells showed enhanced in vitro and in vivo pluripotency phenotype that may support more efficient scale-up strategies and safer clinical implementation.

Stem Cell-Derived Islet Transplantation in Patients With Type 2 Diabetes: Can Diabetes Subtypes Guide Implementation?

Historically, only patients with brittle diabetes or severe recurrent hypoglycemia have been considered for islet transplantation (ITx). This population has been selected to optimize the risk-benefit profile, considering risks of long-term immunosuppression and limited organ supply. However, with the advent of stem cell (SC)-derived ITx and the potential for immunosuppression-free ITx, consideration of a broader recipient cohort may soon be justified. Simultaneously, the classical categorization of diabetes is being challenged by growing evidence in support of a clustering of disease subtypes that can be better categorized by the All New Diabetics in Scania (ANDIS) classification system. Using the ANDIS classification, 5 subtypes of diabetes have been described, each with unique causes and consequences. We evaluate consideration for ITx in the context of this broader patient population and the new classification of diabetes subtypes. In this review, we evaluate considerations for ITx based on novel diabetes subtypes, including their limitations, and we elaborate on unique transplant features that should now be considered to enable ITx in these "unconventional" patient cohorts. Based on evidence from those receiving whole pancreas transplant and our more than 20-year experience with ITx, we offer recommendations and potential research avenues to justify implementation of SC-derived ITx in broader populations of patients with all types of diabetes.

Long-term outcomes after normothermic machine perfusion in liver transplantation-Experience at a single North American center.

Normothermic machine perfusion (NMP) has emerged as a valuable tool in the preservation of liver allografts before transplantation. Randomized trials have shown that replacing static cold storage (SCS) with NMP reduces allograft injury and improves graft utilization. The University of Alberta's liver transplant program was one of the early adopters of NMP in North America. Herein, we describe our 7-year experience applying NMP to extend preservation time in liver transplantation using a "back-to-base" approach. From 2015 to 2021, 79 livers were transplanted following NMP, compared with 386 after SCS only. NMP livers were preserved for a median time of minutes compared with minutes in the SCS cohort (P < .0001). Despite this, we observed significantly improved 30-day graft survival (P = .030), although there were no differences in long-term patient survival, major complications, or biliary or vascular complications. We also found that although SCS time was strongly associated with increased graft failure at 1 year in the SCS cohort (P = .006), there was no such association among NMP livers (P = .171). Our experience suggests that NMP can safely extend the total preservation time of liver allografts without increasing complications.

Pancreas and Islet Transplantation: Comparative Outcome Analysis of a Single-centre Cohort Over 20-years.

OBJECTIVE: To provide the largest single-center analysis of islet (ITx) and pancreas (PTx) transplantation. SUMMARY BACKGROUND DATA: Studies describing long-term outcomes with ITx and PTx are scarce. METHODS: We included adults undergoing ITx (n=266) and PTx (n=146) at the University of Alberta from January 1999 to October 2019. Outcomes include patient and graft survival, insulin independence, glycemic control, procedure-related complications, and hospital readmissions. Data are presented as medians (interquartile ranges, IQR) and absolute numbers (percentages, %) and compared using Mann-Whitney and χ2 tests. Kaplan-Meier estimates, Cox proportional hazard models and mixed main effects models were implemented. RESULTS: Crude mortality was 9.4% and 14.4% after ITx and PTx, respectively ( P= 0.141). Sex-adjusted and age-adjusted hazard-ratio for mortality was 2.08 (95% CI, 1.04-4.17, P= 0.038) for PTx versus ITx. Insulin independence occurred in 78.6% and 92.5% in ITx and PTx recipients, respectively ( P= 0.0003), while the total duration of insulin independence was 2.1 (IQR 0.8-4.6) and 6.7 (IQR 2.9-12.4) year for ITx and PTx, respectively ( P= 2.2×10 -22 ). Graft failure ensued in 34.2% and 19.9% after ITx and PTx, respectively ( P =0.002). Glycemic control improved for up to 20-years post-transplant, particularly for PTx recipients (group, P= 7.4×10 -7 , time, P =4.8×10 -6 , group*time, P= 1.2×10 -7 ). Procedure-related complications and hospital readmissions were higher after PTx ( P =2.5×10 -32 and P= 6.4×10 -112 , respectively). CONCLUSIONS: PTx shows higher sex-adjusted and age-adjusted mortality, procedure-related complications and readmissions compared with ITx. Conversely, insulin independence, graft survival and glycemic control are better with PTx. This study provides data to balance risks and benefits with ITx and PTx, which could improve shared decision-making.

Evaluating the Potential for ABO-incompatible Islet Transplantation: Expression of ABH Antigens on Human Pancreata, Isolated Islets, and Embryonic Stem Cell-derived Islets.

BACKGROUND: ABO-incompatible transplantation has improved accessibility of kidney, heart, and liver transplantation. Pancreatic islet transplantation continues to be ABO-matched, yet ABH antigen expression within isolated human islets or novel human embryonic stem cell (hESC)-derived islets remain uncharacterized. METHODS: We evaluated ABH glycans within human pancreata, isolated islets, hESC-derived pancreatic progenitors, and the ensuing in vivo mature islets following kidney subcapsular transplantation in rats. Analyses include fluorescence immunohistochemistry and single-cell analysis using flow cytometry. RESULTS: Within the pancreas, endocrine and ductal cells do not express ABH antigens. Conversely, pancreatic acinar tissues strongly express these antigens. Acinar tissues are present in a substantial portion of cells within islet preparations obtained for clinical transplantation. The hESC-derived pancreatic progenitors and their ensuing in vivo-matured islet-like clusters do not express ABH antigens. CONCLUSIONS: Clinical pancreatic islet transplantation should remain ABO-matched because of contaminant acinar tissue within islet preparations that express ABH glycans. Alternatively, hESC-derived pancreatic progenitors and the resulting in vivo-matured hESC-derived islets do not express ABH antigens. These findings introduce the potential for ABO-incompatible cell replacement treatment and offer evidence to support scalability of hESC-derived cell therapies in type 1 diabetes.

C-peptide Targets and Patient-centered Outcomes of Relevance to Cellular Transplantation for Diabetes.

BACKGROUND: C-peptide levels are a key measure of beta-cell mass following islet transplantation, but threshold values required to achieve clinically relevant patient-centered outcomes are not yet established. METHODS: We conducted a cross-sectional retrospective cohort study evaluating patients undergoing islet transplantation at a single center from 1999 to 2018. Cohorts included patients achieving insulin independence without hypoglycemia, those with insulin dependence without hypoglycemia, and those with recurrent symptomatic hypoglycemia. Primary outcome was fasting C-peptide levels at 6 to 12 mo postfirst transplant; secondary outcomes included stimulated C-peptide levels and BETA-2 scores. Fasting and stimulated C-peptide and BETA-2 cutoff values for determination of hypoglycemic freedom and insulin independence were evaluated using receiver operating characteristic curves. RESULTS: We analyzed 192 patients, with 122 (63.5%) being insulin independent without hypoglycemia, 61 (31.8%) being insulin dependent without hypoglycemia, and 9 (4.7%) experiencing recurrent symptomatic hypoglycemia. Patients with insulin independence had a median (interquartile range) fasting C-peptide level of 0.66 nmol/L (0.34 nmol/L), compared with 0.49 nmol/L (0.25 nmol/L) for those being insulin dependent without hypoglycemia and 0.07 nmol/L (0.05 nmol/L) for patients experiencing hypoglycemia ( P < 0.001). Optimal fasting C-peptide cutoffs for insulin independence and hypoglycemia were ≥0.50 nmol/L and ≥0.12 nmol/L, respectively. Cutoffs for insulin independence and freedom of hypoglycemia using stimulated C-peptide were ≥1.2 nmol/L and ≥0.68 nmol/L, respectively, whereas optimal cutoff BETA-2 scores were ≥16.4 and ≥5.2. CONCLUSIONS: We define C-peptide levels and BETA-2 scores associated with patient-centered outcomes. Characterizing these values will enable evaluation of ongoing clinical trials with islet or stem cell therapies.

A predictive computational platform for optimizing the design of bioartificial pancreas devices.

The delivery of encapsulated islets or stem cell-derived insulin-producing cells (i.e., bioartificial pancreas devices) may achieve a functional cure for type 1 diabetes, but their efficacy is limited by mass transport constraints. Modeling such constraints is thus desirable, but previous efforts invoke simplifications which limit the utility of their insights. Herein, we present a computational platform for investigating the therapeutic capacity of generic and user-programmable bioartificial pancreas devices, which accounts for highly influential stochastic properties including the size distribution and random localization of the cells. We first apply the platform in a study which finds that endogenous islet size distribution variance significantly influences device potency. Then we pursue optimizations, determining ideal device structures and estimates of the curative cell dose. Finally, we propose a new, device-specific islet equivalence conversion table, and develop a surrogate machine learning model, hosted on a web application, to rapidly produce these coefficients for user-defined devices.

Preclinical systematic review & meta-analysis of cyclosporine for the treatment of myocardial ischemia-reperfusion injury.

Background: Though best known for its immunosuppressant effects, cyclosporine A (CsA) has also been studied as a treatment to mitigate ischemia-reperfusion injury (IRI) by its inhibition of the mitochondria permeability transition pore (mPTP). Despite numerous preclinical studies supporting its benefit in reducing infarct size following myocardial IRI, large randomized controlled clinical trials have been unable to show a beneficial effect. Exploring existing preclinical data can give us the opportunity to revisit some the assumptions that may have led to the failure of these studies to translate clinically. Herein, we present a systematic review of preclinical studies testing CsA to attenuate myocardial IRI (PROSPERO CRD42020159620). Methods: We conducted a systematic search of health research databases Ovid MEDLINE, Ovid EMBASE, Web of Science BIOSIS, and Scopus, as well as Cochrane and PROSPERO systematic review databases, on March 9, 2022 for non-human in vivo animal studies of myocardial IRI, using CsA as a treatment that reported clinically relevant outcomes. Bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation's risk of bias tool and a modified Collaborative Approach to Meta Analysis and Review of Animal Data from Experimental Studies checklist. Sub-group meta-analyses were conducted to identify potential factors influencing outcomes. Results: We identified 71 studies, 59 of which were studies of coronary occlusion. Overall, 75% of studies reported a clear positive effect of CsA in mitigating myocardial IRI by some clinically relevant parameter (e.g., infarct size). A meta-analysis including 43 coronary occlusion studies showed an overall reduction in infarct size with CsA treatment (16.09%; 95% CI: -18.50% to -13.67%). Subgroup meta-analyses identified species, age, timing of administration, and duration of ischemia as factors potentially affecting the efficacy of CsA in the setting of myocardial IRI. Conclusions: Our systematic review and meta-analysis identifies questions that have yet to be answered by preclinical studies, highlighting important differences between these and clinical studies that should be addressed prior to proceeding with any further clinical studies using CsA to treat IRI in the heart or other organs. We also use the example of CsA to highlight general considerations for researchers attempting to translate animal studies into the clinical setting.

Outcomes Following Extrahepatic and Intraportal Pancreatic Islet Transplantation: A Comparative Cohort Study.

BACKGROUND: Preliminary studies show promise for extrahepatic islet transplantation (ITx). However, clinical comparisons with intraportal ITx outcomes remain limited. METHODS: This single-center cohort study evaluates patients receiving extrahepatic or intraportal ITx between 1999 and 2018. Primary outcome was stimulated C-peptide level. Secondary outcomes were fasting plasma glucose, BETA-2 scores, and fasting C-peptide level. Multivariable logistic modeling evaluated factors independently associated with a composite variable of early graft failure and primary nonfunction within 60 d of ITx. RESULTS: Of 264 patients, 9 (3.5%) received extrahepatic ITx (gastric submucosal = 2, subcutaneous = 3, omental = 4). Group demographics were similar at baseline (age, body mass index, diabetes duration, and glycemic control). At 1-3 mo post-first infusion, patients receiving extrahepatic ITx had significantly lower stimulated C-peptide (0.05 nmol/L versus 1.2 nmol/L, P < 0.001), higher fasting plasma glucose (9.3 mmol/L versus 7.3 mmol/L, P < 0.001), and lower BETA-2 scores (0 versus 11.6, P < 0.001) and SUITO indices (1.5 versus 39.6, P < 0.001) compared with those receiving intraportal ITx. Subjects receiving extrahepatic grafts failed to produce median C-peptide ≥0.2 nmol/L within the first 60 d after transplant. Subsequent intraportal infusion following extrahepatic transplants achieved equivalent outcomes compared with patients receiving intraportal transplant alone. Extrahepatic ITx was independently associated with early graft failure/primary non-function (odds ratio 1.709, confidence interval 73.8-39 616.0, P < 0.001), whereas no other factors were independently predictive. CONCLUSIONS: Using current techniques, intraportal islet infusion remains the gold standard for clinical ITx, with superior engraftment, graft function, and glycemic outcomes compared with extrahepatic transplantation of human islets.

Optimizing Generation of Stem Cell-Derived Islet Cells.

Islet transplantation is a highly effective treatment for select patients with type 1 diabetes. Unfortunately, current use is limited to those with brittle disease due to donor limitations and immunosuppression requirements. Discovery of factors for induction of pluripotent stem cells from adult somatic cells into a malleable state has reinvigorated the possibility of autologous-based regenerative cell therapies. Similarly, recent progress in allogeneic human embryonic stem cell islet products is showing early success in clinical trials. Describing safe and standardized differentiation protocols with clear pathways to optimize yield and minimize off-target growth is needed to efficiently move the field forward. This review discusses current islet differentiation protocols with a detailed break-down of differentiation stages to guide step-wise controlled generation of functional islet products.

Pancreatic islet transplantation in type 1 diabetes: 20-year experience from a single-centre cohort in Canada.

BACKGROUND: Islet transplantation offers an effective treatment for selected people with type 1 diabetes and intractable hypoglycaemia. Long-term experience, however, remains limited. We report outcomes from a single-centre cohort up to 20 years after islet transplantation. METHODS: This cohort study included patients older than 18 years with type 1 diabetes undergoing allogeneic islet transplantation between March 11, 1999, and Oct 1, 2019, at the University of Alberta Hospital (Edmonton, AB, Canada). Patients who underwent islet-after-kidney transplantation and islet transplantation alone or islet transplantation before whole-pancreas transplantation (follow-up was censored at the time of whole-pancreas transplantation) were included. Patient survival, graft survival (fasting plasma C-peptide >0·1 nmol/L), insulin independence, glycaemic control, and adverse events are reported. To identify factors associated with prolonged graft survival, recipients with sustained graft survival (≥90% of patient follow-up duration) were compared with those who had non-sustained graft survival (<90% of follow-up duration). Multivariate binary logistic regression analyses were done to determine predictors of sustained graft survival. FINDINGS: Between March 11, 1999, and Oct 1, 2019, 255 patients underwent islet transplantation and were included in the analyses (149 [58%] were female and 218 [85%] were White). Over a median follow-up of 7·4 years (IQR 4·4-12·2), 230 (90%) patients survived. Median graft survival was 5·9 years (IQR 3·0-9·5), and graft failure occurred in 91 (36%) patients. 178 (70%) recipients had sustained graft survival, and 77 (30%) had non-sustained graft survival. At baseline, compared with patients with non-sustained graft survival, those with sustained graft survival had longer median type 1 diabetes duration (33·5 years [IQR 24·3-41·7] vs 26·2 years [17·0-35·5]; p=0·0003), median older age (49·4 years [43·5-56·1] vs 44·2 years [35·4-54·2]; p=0·0011), and lower median insulin requirements (0·53 units/kg per day [0·45-0·67] vs 0·59 units/kg per day [0·48-0·70]; p=0·032), but median HbA1c concentrations were similar (8·2% [7·5-9·0] vs 8·5% [7·8-9·2]; p=0·23). 201 (79%) recipients had insulin independence, with a Kaplan-Meier estimate of 61% (95% CI 54-67) at 1 year, 32% (25-39) at 5 years, 20% (14-27) at 10 years, 11% (6-18) at 15 years, and 8% (2-17) at 20 years. Patients with sustained graft survival had significantly higher rates of insulin independence (160 [90%] of 178 vs 41 [53%] of 77; p<0·0001) and sustained improvements in glycaemic control mixed-main-effects model group effect, p<0·0001) compared with those with non-sustained graft survival. Multivariate analyses identified the combined use of anakinra plus etanercept (adjusted odds ratio 7·5 [95% CI 2·7-21·0], p<0·0001) and the BETA-2 score of 15 or higher (4·1 [1·5-11·4], p=0·0066) as factors associated with sustained graft survival. In recipients with sustained graft survival, the incidence of procedural complications was lower (23 [5%] of 443 infusions vs 17 [10%] of 167 infusions; p=0·027), whereas the incidence of cancer was higher (29 of [16%] of 178 vs four [5%] of 77; p=0·015) than in those with non-sustained graft survival; most were skin cancers (22 [67%] of 33). End-stage renal disease and severe infections were similar between groups. INTERPRETATION: We present the largest single-centre cohort study of long-term outcomes following islet transplantation. Although some limitations with our study remain, such as the retrospective component, a relatively small sample size, and the absence of non-transplant controls, we found that the combined use of anakinra plus etanercept and the BETA-2 score were associated with improved outcomes, and therefore these factors could inform clinical practice. FUNDING: None.

Current Status, Barriers, and Future Directions for Humanized Mouse Models to Evaluate Stem Cell-Based Islet Cell Transplant.

Islet cell transplant (ITx) continues to improve, with recently published long-term outcomes suggesting nearly 80% graft survival, leading to improvements in glycemic control, reductions in insulin doses, and near-complete abrogation of severe hypoglycemia. Unfortunately, access to ITx remains limited by immunosuppression requirements and donor supply. Discovery of stem cell-derived functional islet-like clusters with the capacity to reverse diabetes offers a renewable, potentially immunosuppression-free solution for future widespread ITx. Evaluation and optimization of these therapies is ongoing, but may one day provide a realistic cure for type 1 diabetes. However, stem cell-based ITx has unique immunologic questions that remain unanswered. Here, we briefly synthesize current approaches for stem cell-derived ITx, review humanized mice models, and elaborate on the potential of humanized mice models for bridging the gap between current small rodent models and human clinical trials for allogeneic and autologous inducible pluripotent stem cell (iPSC)-based ITx while highlighting limitations and future directions.

Prospective predictive performance comparison between clinical gestalt and validated COVID-19 mortality scores.

Most COVID-19 mortality scores were developed at the beginning of the pandemic and clinicians now have more experience and evidence-based interventions. Therefore, we hypothesized that the predictive performance of COVID-19 mortality scores is now lower than originally reported. We aimed to prospectively evaluate the current predictive accuracy of six COVID-19 scores and compared it with the accuracy of clinical gestalt predictions. 200 patients with COVID-19 were enrolled in a tertiary hospital in Mexico City between September and December 2020. The area under the curve (AUC) of the LOW-HARM, qSOFA, MSL-COVID-19, NUTRI-CoV, and NEWS2 scores and the AUC of clinical gestalt predictions of death (as a percentage) were determined. In total, 166 patients (106 men and 60 women aged 56±9 years) with confirmed COVID-19 were included in the analysis. The AUC of all scores was significantly lower than originally reported: LOW-HARM 0.76 (95% CI 0.69 to 0.84) vs 0.96 (95% CI 0.94 to 0.98), qSOFA 0.61 (95% CI 0.53 to 0.69) vs 0.74 (95% CI 0.65 to 0.81), MSL-COVID-19 0.64 (95% CI 0.55 to 0.73) vs 0.72 (95% CI 0.69 to 0.75), NUTRI-CoV 0.60 (95% CI 0.51 to 0.69) vs 0.79 (95% CI 0.76 to 0.82), NEWS2 0.65 (95% CI 0.56 to 0.75) vs 0.84 (95% CI 0.79 to 0.90), and neutrophil to lymphocyte ratio 0.65 (95% CI 0.57 to 0.73) vs 0.74 (95% CI 0.62 to 0.85). Clinical gestalt predictions were non-inferior to mortality scores, with an AUC of 0.68 (95% CI 0.59 to 0.77). Adjusting scores with locally derived likelihood ratios did not improve their performance; however, some scores outperformed clinical gestalt predictions when clinicians' confidence of prediction was <80%. Despite its subjective nature, clinical gestalt has relevant advantages in predicting COVID-19 clinical outcomes. The need and performance of most COVID-19 mortality scores need to be evaluated regularly.

Tumor necrosis factor receptor superfamily member 25 (TNFRSF25) agonists in islet transplantation: Endogenous in vivo regulatory T cell expansion promotes prolonged allograft survival.

Regulatory T cells (Tregs) modulate alloimmune responses and may facilitate minimization or withdrawal of immunosuppression posttransplant. Current approaches, however, rely on complex ex vivo Treg expansion protocols. Herein, we explore endogenous in vivo Treg expansion through antibody-mediated agonistic stimulation of the tumor necrosis factor receptor superfamily member 25 (TNFRSF25) pathway and its potential to prolong graft survival in a mouse model of islet allotransplantation. C57BL/6 male mice were treated with a single dose of TNFRSF25 agonistic antibodies (4C12 or mPTX-35) or IgG control. Diabetes was induced using streptozotocin. Four days later, flow cytometry was completed to corroborate Treg expansion, and 500 islets (CBA/J male mice) were transplanted. Glycemia was assessed thrice weekly until rejection/endpoint. Early intra-graft Treg infiltration was assessed 36 h posttransplant. TNFRSF25 antibodies enabled pronounced Treg expansion and treated mice had significantly prolonged graft survival compared with controls (p < .001). Additionally, the degree of Treg expansion significantly correlated with graft survival (p < .001). Immunohistochemistry demonstrated marked Treg infiltration in long-term surviving grafts; intra-graft Treg infiltration occurred early posttransplant. In conclusion, a single dose of TNFRSF25 antibodies enabled in vivo Treg expansion, which promotes prolonged graft survival. TNFRSF25-mediated in vivo Treg expansion could contribute to achieving lasting immunological tolerance in organ transplantation.