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Human islet transplantation would offer a less invasive and more physiological alternative than whole pancreas transplantation and insulin injections respectively for the treatment of diabetes mellitus if islet graft survival can be improved, initial recipient post-transplant insulin independence declines to <10% after 5 years. Factors contributing to graft failure include enzymatic disruption of the islet microenvironment during isolation, diabetogenic effects of immunosuppressants and metabolic stress resulting from slow revascularisation. Aims: To investigate the effect of co-culture in both static (SC) and rotational culture (RC) of BRINBDU beta-cells (Dl 1) and human umbilical vein endothelial cells (HUVEC) on D11 insulin secretion; and the effect of a thiazolidmedione (TZD) on Dl 1 function and HUVEC proliferation. To assess the effect of culture media, SC, RC and a TZD on human islet morphology, insulin secretion and VEGF production. To initiate in vivo protocol development for assessment of revascularisation of human islet grafts.

Beta-cell survival is low following islet transplantation and this may be linked to a delay in revascularisation of donor cells. This decrease in oxygen supply is termed hypoxia, the result of which is detrimental to beta-cell survival. The current research sought to investigate post-transplant beta-cell viability and function by investigating the effects of low oxygen levels on MIN6 pancreatic beta-cells. MIN6 beta-cells were exposed to 1% oxygen (hypoxia) or 21% oxygen (normoxia) over a period of 72 hours. Viability was assessed by MTT assay and cell number was determined by haemocytometer count at 0 hours (normoxia), 24 hours, 48 hours and 72 hours. A Hoechst propidium iodide (HPI) stain was used to identify beta-cell apoptosis or necrosis during hypoxia. Western blot analyses were performed to determine the PI3K, pAkt, pAMPK, PDX-1, GLUT2 and pS6K protein levels. Real time PCR was used to estimate glut2, vegf, hif and insulin gene expression by MIN6 cells following exposure to hypoxia over various time points.