Islet transplantation and the challenges of treating type 1 diabetes

Extract: Diabetes affects over 18 million people in the United States. Approximately one million have type 1 diabetes mellitus (T1D), previously known as juvenile onset diabetes, with the rest of patients having the type 2 diabetes, previously known as adult onset diabetes. Of these two forms of diabetes, T1D is considered more severe since, if left untreated, it is more rapidly fatal than type 2. Furthermore, achieving blood glucose control in patients with T1D tends to be more difficult. Clinician scientists recognized shortly after the 1921 discovery of insulin that it was a miraculous advance in the treatment of diabetes, but it still fell far short of a cure. Therapy for diabetes has since made major strides but substantial difficulties remain for those afflicted, and a cure is still being sought. Current data strongly suggests that T1D is caused by an attack by the immune system on the the pancreatic beta-cells, the cells that physiologically regulate insulin secretion. These beta-cells are located within cell clusters of the pancreas known as the Islets of Langerhans (or simply "islets"). The islets are essentially mini-organs; they are cell clusters composed of an array of endocrine cell types which variously secrete insulin (to lower the blood sugar, along with other effects), glucagon (a hormone released that raises blood sugar levels), somatostatin (a neuropeptide), pancreatic polypeptide, and the recently described hormone resistin. Before insulin was first used therapeutically in 1922, T1D was uniformly fatal.