Method for the isolation of human pancreatic islets for clinical transplantation in type 1 diabetes mellitus

Islet transplantation is a modern method of treating severe type 1 diabetes mellitus (T1D). However, multiple factors can negatively affect both the efficiency of islet isolation and subsequent transplantation outcomes. Consequently, ongoing efforts to optimize isolation techniques have led to the emergence of new unique protocols.

The objective of this study is to evaluate the effectiveness of a modified method for isolating pancreatic islets (islets of Langerhans) from deceased donors for clinical transplantation in recipients with T1D.

Materials and methods. Pancreatic islets were isolated using a modified technique that excluded the use of the Ricordi islet isolator during the enzymatic digestion stage, as well as density gradient centrifugation during the purification stage. Islet identification was performed using dithizone staining. Islet viability was assessed by fluorescent staining with acridine orange and propidium iodide. Functional activity was evaluated by determining the stimulation index using enzyme-linked immunosorbent assay (ELISA). Histological examination of the native pancreas (n = 3) included routine staining, as well as immunohistochemical analysis targeting the main types of islet cells.

Results. Pancreatic islets isolated from the pancreas of deceased donors using the modified technique retained their structural integrity and demonstrated variability in size and shape. The total islet yield was 630,000 ± 30,000, with a viability rate of 90 ± 3% and a stimulation index of 1.41 ± 0.01. These findings indicate the high quality of the isolated biomaterial and confirm the ability of β-cells to respond to changes in glucose content. Morphological assessment of the donor pancreas demonstrated preserved structural integrity of the islet apparatus, supporting the potential for obtaining viable and functionally active islets. The efficiency of islet isolation during enzymatic pancreatic processing was also confirmed.

Conclusion. Optimization of the methodological approach enabled the development and validation of a modified technique for processing the pancreas of deceased donors, resulting in the isolation of a substantial number of viable and functional islets of Langerhans. The characteristics of the obtained islet graft support its suitability for clinical transplantation in T1D patients.

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