Islet Autotransplantation to Preserve Beta Cell Mass in Selected Patients With Chronic Pancreatitis and Diabetes Mellitus Undergoing Total Pancreatectomy

Objectives: Islet autotransplantation (IAT) is performed in nondiabetic patients with chronic pancreatitis at the time of total pancreatectomy (TP) to minimize risk of postoperative diabetes. The role of TP-IAT in patients with chronic pancreatitis and C-peptide-positive diabetes is not established. We postulate that IAT can preserve beta cell mass and thereby benefit patients with preexisting diabetes undergoing TP. Methods: Preoperative metabolic testing, islet isolation outcomes, and subsequent islet graft function were reviewed for 27 patients with diabetes mellitus and chronic pancreatitis undergoing TP-IAT. The relationships between the results of preoperative metabolic testing and islet isolation outcomes were explored using regression analysis. Results: Mean islet yield was 2060 (SD, 2408) islet equivalents/kg. Peak C-peptide (from mixed meal tolerance testing) was the strongest predictor of islet yield, with higher stimulated C-peptide levels associated with greater islet mass. Half of the patients who had C-peptide levels measured after transplantation demonstrated C-peptide production at a level that conveys protective benefit in type 1 diabetes (>= 0.6 ng/mL). Conclusions: These findings provide proof of concept that significant islet mass can be isolated in patients with chronic pancreatitis and C-peptide-positive diabetes mellitus undergoing TP-IAT. Stimulated C-peptide may be a useful marker of islet mass before transplantation in these patients.