Cell therapy to cure
Patients with diabetes are well aware that their risk of long-term complications is minimised by the maintenance of near-normoglycaemia. Intensive therapy regimens designed to achieve this in people with insulin deficient diabetes (Type 1 and late Type2) require detailed understanding of the actions of insulin preparations and their interaction with food and daily activities, multiple daily injections and frequent self monitoring of blood glucose concentrations. There is the ever-present fear of hypoglycaemia, sufficient to cause confusion. The goal of research is therefore glucose driven insulin delivery. While in vivo glucose monitoring remains imperfect and costly, interest in replacing the biological systems for glucose responsive insulin delivery is rising. Whole organ pancreas transplantation can create total insulin independence but 98% of the pancreas is not concerned with insulin secretion and the fragile pancreatic structure and the potential toxicity of its enzyme secretions makes this a procedure not to be undertaken lightly. Islet transplantation is now feasible but at limited efficiency–it cannot, in its present form, achieve insulin independence in people who need large amounts of insulin to combat insulin resistance or large body size for example. This is in part because of losses in isolation but also losses accrued after implantation. The drugs used to suppress graft rejection and recurrence of Type 1 diabetes are toxic–both to the recipient and sometimes to the islets! However, islet transplantation in its present form is highly successful in stopping severe hypoglycaemia and can and should be available for this purpose while research into new islet sources, better preservation of islet function and more targeted, less toxic immunosuppression proceeds. Ultimately, the treatment for Type 1 diabetes at least should be replacement of the cells that have been lost, as with any other transplantation procedure.