Human research islet cell culture outcomes at the Alberta Diabetes Institute IsletCore.

Human islets from deceased organ donors have made important contributions to our understanding of pancreatic endocrine function and continue to be an important resource for research studies aimed at understanding, treating, and preventing diabetes. Understanding the impacts of isolation and culture upon the yield of human islets for research is important for planning research studies and islet distribution to distant laboratories. Here, we examine islet isolation and cell culture outcomes at the Alberta Diabetes Institute (ADI) IsletCore (n = 197). Research-focused isolations typically have a lower yield of islet equivalents (IEQ), with a median of 252,876 IEQ, but a higher purity (median 85%) than clinically focused isolations before culture. The median recovery of IEQs after culture was 75%, suggesting some loss. This was associated with a shift toward smaller islet particles, indicating possible islet fragmentation, and occurred within 24 h with no further loss after longer periods of culture (up to 136 h). No overall change in stimulation index as a measure of islet function was seen with culture time. These findings were replicated in a representative cohort of clinical islet preparations from the Clinical Islet Transplant Program at the University of Alberta. Thus, loss of islets occurs within 24 h of isolation, and there is no further impact of extended culture prior to islet distribution for research.

Evaluating Islet Cell Isolation and Transplantation From Donors Following Medical Assistance in Dying.

Background: Limited information is available regarding outcomes of islet cell isolation (ICI) and transplantation (ITx) using medical assistance in dying (MAiD) donors. We aimed to assess the feasibility and outcomes of ICI and ITx in MAiD donors. Methods: ICI and ITx from MAiD were compared with donation after circulatory death (DCD) type III between 2016 and 2023. Differences of isolated islet equivalents (IEQs), numeric viability and other quantitative in vitro metabolic measures were assessed. Results: Overall, 81 ICIs were available of whom 34 (42%) and 47 (58%) from MAiD and DCD-III, respectively. There were no differences of pancreas and digested tissue weight and islets viability among the 2 groups; however, cold ischemic time was longer in MAiD (11.5 versus 9.1 h; P = 0.021). The IEQ (P < 0.001) and percent trapped (P < 0.001) were higher in the DCD-III; however, MAiD islets demonstrated a higher purity (P = 0.020). Overall, 15 ITx were performed of whom 3 (8.8%) and 12 (25.5%) from MAiD and DCD-III, respectively (P = 0.056). Patients had a median fasting C-peptide of 0.51 ng/mL (interquartile range, 0.30-0.76 nmol/L), with no differences between groups (MAiD = 0.52 versus DCD-III = 0.51; P = 0.718). The median HbA1c was 6.2% (interquartile range, 5.7%-7%) (MAiD = 6.3% versus DCD-III = 6.1%; P = 0.815) and BETA2 scores (MAiD = 7.4 versus DCD-III = 12.8; P = 0.229) did not differ. Conclusions: ICI from MAiD donor pancreas may be successfully transplanted with comparable outcomes to DCD-III and may be used for research. These results justify additional efforts to consider MAiD as another valuable source of grafts for ITx. Further multicenter studies and larger clinical experience are needed to validate our findings.

Proteomic predictors of individualized nutrient-specific insulin secretion in health and disease.

Population-level variation and mechanisms behind insulin secretion in response to carbohydrate, protein, and fat remain uncharacterized. We defined prototypical insulin secretion responses to three macronutrients in islets from 140 cadaveric donors, including those with type 2 diabetes. The majority of donors' islets exhibited the highest insulin response to glucose, moderate response to amino acid, and minimal response to fatty acid. However, 9% of donors' islets had amino acid responses, and 8% had fatty acid responses that were larger than their glucose-stimulated insulin responses. We leveraged this heterogeneity and used multi-omics to identify molecular correlates of nutrient responsiveness, as well as proteins and mRNAs altered in type 2 diabetes. We also examined nutrient-stimulated insulin release from stem cell-derived islets and observed responsiveness to fat but not carbohydrate or protein-potentially a hallmark of immaturity. Understanding the diversity of insulin responses to carbohydrate, protein, and fat lays the groundwork for personalized nutrition.

Proteomic predictors of individualized nutrient-specific insulin secretion in health and disease.

Population level variation and molecular mechanisms behind insulin secretion in response to carbohydrate, protein, and fat remain uncharacterized despite ramifications for personalized nutrition. Here, we define prototypical insulin secretion dynamics in response to the three macronutrients in islets from 140 cadaveric donors, including those diagnosed with type 2 diabetes. While islets from the majority of donors exhibited the expected relative response magnitudes, with glucose being highest, amino acid moderate, and fatty acid small, 9% of islets stimulated with amino acid and 8% of islets stimulated with fatty acids had larger responses compared with high glucose. We leveraged this insulin response heterogeneity and used transcriptomics and proteomics to identify molecular correlates of specific nutrient responsiveness, as well as those proteins and mRNAs altered in type 2 diabetes. We also examine nutrient-responsiveness in stem cell-derived islet clusters and observe that they have dysregulated fuel sensitivity, which is a hallmark of functionally immature cells. Our study now represents the first comparison of dynamic responses to nutrients and multi-omics analysis in human insulin secreting cells. Responses of different people's islets to carbohydrate, protein, and fat lay the groundwork for personalized nutrition. ONE-SENTENCE SUMMARY: Deep phenotyping and multi-omics reveal individualized nutrient-specific insulin secretion propensity.

HumanIslets: An integrated platform for human islet data access and analysis.

Comprehensive molecular and cellular phenotyping of human islets can enable deep mechanistic insights for diabetes research. We established the Human Islet Data Analysis and Sharing (HI-DAS) consortium to advance goals in accessibility, usability, and integration of data from human islets isolated from donors with and without diabetes at the Alberta Diabetes Institute (ADI) IsletCore. Here we introduce HumanIslets.com, an open resource for the research community. This platform, which presently includes data on 547 human islet donors, allows users to access linked datasets describing molecular profiles, islet function and donor phenotypes, and to perform various statistical and functional analyses at the donor, islet and single-cell levels. As an example of the analytic capacity of this resource we show a dissociation between cell culture effects on transcript and protein expression, and an approach to correct for exocrine contamination found in hand-picked islets. Finally, we provide an example workflow and visualization that highlights links between type 2 diabetes status, SERCA3b Ca2+-ATPase levels at the transcript and protein level, insulin secretion and islet cell phenotypes. HumanIslets.com provides a growing and adaptable set of resources and tools to support the metabolism and diabetes research community.

El dolor cardíaco y su significado

Tomado de The New England Journal of Medicine, nov. 19, 1936, p. 953