Assessment of Insulin Production From Native Pancreas in Patients With Pancreas Transplants

Type 1 diabetes mellitus (T1DM) is thought to result from an autoimmune destruction of insulin producing beta-cells found within the pancreatic islets of Langerhans. In addition to the autoimmune process however, many studies have shown that hyperglycemia is also toxic to islets. Interventional studies have shown, for instance, that either tight glycemia control or immunosuppression can preserve C-peptide production. We hypothesize that patients who are immunosuppressed and euglycemic will display evidence that their native pancreas has recovered beta-cell function. We have asked whether pancreas transplant recipients, due to the immunosuppression required to prevent allograft loss, and the improved glycemia control resulting from the transplanted pancreas, might display some recovery of their native pancreatic islet function. Our preliminary data suggest that patients without C-peptide production prior to receiving an islet transplant appear to recover some endogenous pancreatic insulin secretion after islet transplantation. We will study whole pancreas transplant recipients, specifically those with grafts functioning for at least 5 years. We will test for native pancreas insulin production by infusing arginine into a peripheral vein, then selectively/simultaneously sampling blood for C-peptide levels from the hepatic veins and the vein draining the pancreatic allograft . Unlike our previous study of islet transplant recipients, a study that required portal vein cannulation, this study will require only hepatic and iliac vein cannulations, both much easier to accomplish, and associated with much less risk to the patient. Samples obtained from these sites will be tested for C-peptide levels. In addition, if we find evidence of native pancreas insulin production, we will look at a variety of clinical variables to see if any correlate with recovery of function.

• INCLUSION CRITERIA:

Patients will be included if:

Age greater than or equal to 18

GFR greater than 50 ml/min/1.73 m2

History consistent with T1DM prior to pancreas transplant

Exclusion criteria

Liver dysfunction (elevated liver enzymes, clinical evidence of portal hypertension)

coagulopathy (elevated INR or Partial Thromboplastin Time)

History of repeated instrumentation/cannulation in the jugular or femoral vessels

Dye allergy

Pregnancy

Known vascular anomalies

Anemia with Hgb less than 10