Islet cell transplantation

PURPOSE OF REVIEW: The transplantation of human islets has come a long way since the first diabetic person became insulin independent in 1989. The advent of a steroid-free immunosuppressive protocol in 2000 resulted in most recipients becoming insulin independent and remaining so for a year. However, β-cell function declines thereafter. Strategies to enhance the islet mass transplanted and preserve β-cell function are necessary. RECENT FINDINGS: This review covers recent advances in determining the selection of appropriate enzymes for islet isolation, use of pancreases from heart-dead donors and techniques for predicting the functional capacity of isolated islets prior to transplantation. Changing the transplantation site away from the liver, where many islets are destroyed by an inflammatory process, is reviewed, and the possibility of seeding islets onto three-dimensional biodegradable scaffolds discussed. A method of preventing apoptosis of the β cells prior to transplantation is detailed, as is the beneficial effect of using exenatide, after transplantation. Novel techniques to image islets are discussed, and this requires the labelling of the islets prior to implantation. Enhancing the vascularization of islets is shown to enhance functional outcomes. Encapsulation of the islets should obviate the need for using antirejection drugs, and it may be possible to expand β cells in vitro. SUMMARY: The above strategies are likely to enhance the outcomes of clinical islet transplants.