Understanding the Structural Arrangement of Islets in Chronic Pancreatitis.

Islet transplantation has become an established method for the treatment of insulin-deficient diabetes such as type 1 and type 3C (pancreatogenic). An effective transplantation necessitates a thorough understanding of the islet architecture and related functions to improve engraftment outcomes. However, in chronic pancreatitis (CP), the structural and related functional information is inadequate. Hence, the present study is aimed to understand the cytoarchitecture of endocrine cells and their functional implications in CP with and without diabetes. Herein, a set of human pancreatic tissue specimens (normal, n=5 and CP, n=20) was collected and processed for islet isolation. Furthermore, immunohistochemistry was used to assess the vascular densities, cell mass, organization, and cell-cell interactions. The glucose-stimulated insulin release results revealed that in chronic pancreatitis without diabetes mellitus altered (CPNDA), at basal glucose concentration the insulin secretion was increased by 24.2%, whereas at high glucose concentration the insulin levels were reduced by 77.4%. The impaired insulin secretion may be caused by alterations in the cellular architecture of islets during CP progression, particularly in chronic pancreatitis with diabetes mellitus and CPNDA conditions. Based on the results, a deeper comprehension of islet architecture would be needed to enhance successful transplantation in CP patients: (J Histochem Cytochem XX.XXX-XXX, XXXX).

Long-term functions of encapsulated islets grafted in nonhuman primates without immunosuppression.

BACKGROUND: Long-term survival and functions of encapsulated islet grafts need to be evaluated in the absence of immunosuppression. The present study aimed to assess the viability and functions of macroencapsulated islets grafted in nonhuman primates without immunosuppression for 1 year. METHODS: Islet transplantations were performed in partially pancreatectomized rhesus monkeys (two autologous and four allogenic) without immunosuppression using immunoisolatory devices. Macroencapsulated islets were implanted subcutaneously (5000-8000 IEQ/device) at two sites (left thigh and interscapular region) and were explanted at 2, 6, and 12 months after implantation. Staining for viability and apoptosis, in vivo and in vitro glucose-stimulated insulin release, expression of insulin and glucagon genes, and histopathologic examination of the device were used to assess engraftment potential, viability, and functions of islets. Animals were regularly monitored for dietary intake, body weight, and fasting blood glucose levels after islet transplantation. RESULTS: Devices explanted showed vascularization at the end of 2, 6, and 12 months with occasional lymphocytes and minimal fibrosis outside the device. Flow cytometric analysis revealed 97.9%±1.5% and 94.3%±5.71% viable ß cells in interscapular site and thigh in autologous recipients and 85.6%±4.01% (interscapular site) and 74.1%±12.05% (thigh) viable ß cells in allogenic islet recipients. In vivo glucose challenge test revealed significantly increased glucose-stimulated insulin release (P=0.028) in the left thigh with implant (17.58±3.13 mU/L) compared with the thigh without implant (9.86±1.063 mU/L). Insulin and glucagon gene expression was evident in islets recovered from explanted device. CONCLUSIONS: These results indicate that subcutaneous implantation of macroencapsulated islets is minimally invasive and has potential for transplantation without immunosuppression.

Identification of circulating CD90 CD73 cells in cirrhosis of liver.

AIM: To identify circulating CD90(+) CD73(+) CD45(-) cells and evaluate their in vitro proliferating abilities. METHODS: Patients with cirrhosis (n = 43), and healthy volunteers (n = 40) were recruited to the study. Mononuclear cells were isolated and cultured from the peripheral blood of controls and cirrhosis patients. Fibroblast-like cells that appeared in cultures were analyzed for morphological features, enumerated by flow cytometry and confirmed by immunocytochemistry (ICC). Colony forming efficiency (CFE) of these cells was assessed and expressed as a percentage. RESULTS: In comparison to healthy volunteers, cells obtained from cirrhotic patients showed a significant increase (P < 0.001) in the percentage of CD90(+) CD73(+) CD45(-) cells in culture. Cultured cells also showed 10 fold increases in CFE. Flow cytometry and ICC confirmed that the proliferating cells expressed CD90(+) CD73(+) in the cultures from cirrhosis patients. CONCLUSION: These results indicate the presence of circulating CD90(+) CD73(+) CD45(-) cells in patients with liver cirrhosis that have the potential to proliferate at a higher rate.