The Effects of Hypoxia and Cytotoxic Stress on β-cells During Transplantation

Abstract

Type 1 diabetes is a devastating disorder resulting from the autoimmune destruction of insulin-producing β-cells within the islets of Langerhans. Complications from hyperglycemia lead to a lower quality of life characterized by seizures, heart attack, kidney failure or retinopathy. Recent advances in islet cell transplantation have presented a possible cure for Type 1 diabetes, however the viability of a graft is drastically lowered by hypoxia and cytotoxic stress during isolation and transplantation. In this study, we mimicked the process of islet transplantation by exposing rat INS-1 cells to hypoxia (1% oxygen) and three different concentrations of three cytokines (IL-1β, TNF-α and IFN-gamma) for 24 hours and analyzed their effects via oxygen consumption rate (OCR), ATP and caspase assay. Results from this study would be able to characterize the extent of the effects of hypoxia on graft viability and could implicate the most potent cytokine at a specific concentration. Results could also suggest a specific pathway that a certain cytokine uses. Implications from this study can lead to improved methods of transplanting islet cells, perhaps via additives such as tocopherols, antioxidants, or JNK inhibitors that may increase islet protection throughout the transplantation process. If graft viability can be increased, this can increase the availability of islet cells and quality of life for Type 1 diabetic patients.