Endocrine Abstracts

In type 1 diabetes mellitus the insulin-secreting β-cells in pancreatic islets of Langerhans are selectively destroyed by autoimmune assault. Since diabetes is caused by the loss of a single cell type it is amenable to treatment by cell replacement therapy. Advances in islet transplantation procedures have demonstrated that people with type 1 diabetes can be cured by human islet transplantation, but the severely limited availability of donor islets has restricted the wide-spread application of this approach, and driven the search for substitute transplant tissues. Recent experimental studies suggest that three separate sources of tissue show therapeutic potential – xenografts from other species, tissue stem cells and embryonic stem cells. Of these, xenografts are closest to clinical application but there are still major obstacles to be overcome including the development of effective encapsulation strategies to hide the graft from the host’s immune system. Insulin-expressing cells have been derived from a number of different stem cell populations but embryonic stem cells and induced pluripotent stem cells offer the major advantage of being able, in principle, of providing the vast numbers of cells required for transplantation therapy. Despite recent experimental advances in generating insulin-expressing cells from stem cells there remain considerable technical problems in generating safe and clinically useful β-cell substitutes.