Islet Cell Transplants for Diabetes

The purpose of this study is to test the safety and efficacy of islet cell transplants for the treatment of type 1 diabetes mellitus. It has been shown that normal control of blood sugar levels can prevent progression of complications (such as kidney disease, nerve damage, and vascular disease) from diabetes. This research study is designed to see if normal blood sugar control can be achieved by transplanting pancreatic islet cells into your liver, which may reduce or eliminate your need for insulin. Patients may qualify to participate in this research study if they have type 1 diabetes mellitus for at least five years and meet at least one of the following criteria: * Experience hypoglycemic unawareness - Defined as inability to tell when blood glucose is low (for example, may not feel symptoms such as shaking, sweating, and rapid heartbeat that usually signify that glucose is low) * Have been hospitalized several times in the past year for low blood sugar and/or high blood sugar * Have complications of diabetes such as retinopathy, kidney problems, or neuropathy