The prevalence of overweight and obesity is high among private schools in Chennai, and hypertension is also common.

The aim of this study was to assess recovery, cell death, and cell composition of post-thaw cultured human islets. Cryopreserved islets were provided by the Clinical Islet Transplant Program, Edmonton, Canada. Islets were processed using media prepared in accordance with Pre-Edmonton and Edmonton protocols. Cryopreserved islets were rapidly thawed and cultured for 24 h, 3 d, 5 d, and 7 d, following which they were processed for histology. Islet quantification, integrity, morphology and tissue turnover were studied via hematoxylin and eosin stained sections. Ultrastructure was studied by electron microscopy and endocrine cell composition by immunohistochemistry. Using the Pre-Edmonton protocol, islet recovery was 50.1% and islet survival was 50% at 24 h while for the Edmonton protocol, the islet recovery was 69.4% (p<0.001) and islet survival, 50% at ≈2.5 d. With an increasing culture duration although the physical integrity was retained there was an increasing loss of cohesivity both at light microscopic and at ultrastructure level regardless of the protocols used. Percentage islet survival and tissue turnover correlated negatively with culture duration in both protocols. The Edmonton protocol appears to preserve the islets better. However, culture duration adversely affects islet survival and quality, indicating the need for more optimal cryopreservation and culture techniques.

Background: Among the current quality control assays used in islet transplantation, there is an urgent need for more appropriate assays that measure cell damage via apoptosis that are accurate and rapid. Although the Terminal Uridine Nucleotide End Labeling (TUNEL) is a popular marker for apoptosis, the protocol takes 4 hours to complete. In this regard, microwave assisted histoprocessing, which shortens the time taken for processing, holds promise. Keeping this in mind, a new TUNEL Microwave (TUNEL-MW) method, for rapid quantification of apoptosis, was designed, developed and validated. Method: Two lots of post-thaw isolated human islets cultured for 24 hours, 3 days, 5 days and 7 days i.e. 8 samples, were used for the study. Dewaxed and rehydrated tissues were processed for routine histology, stained with haematoxylin and eosin (H&E) and the conventional TUNEL was carried out as per manufacturer’s instructions. For the TUNEL-MW, kit instructions were modified and microwave-assisted histoprocessing was done. The assessment of apoptotic index (AI%) by light microscopy (LM) was carried out by a pathologist who was completely blinded to the study. Results: The new TUNEL-Microwave (TUNEL-MW) developed by us reduced processing time from 4 hours to 30 minutes (saving 3½ hours). Results were validated by univariate linear regression (r2>0.990), coefficient of variation (<5% between all three methods) and the Bland Altman plot comparing AI% determined by the new TUNEL-MW with the conventional TUNEL and with LM (gold standard). Conclusion: TUNEL Microwave appears to be an ideal method. It is simple and takes just 30 minutes to perform and can therefore be used along with existing quality control measures to rule out or measure apoptosis prior to islet release for islet transplantation.