Evaluation of engraftment after single islet transplantation from a brain-dead donor by the secretory unit of islet transplant objects (SUITO) index.

ABSTRACT

BACKGROUND: Evaluation of engraftment is important to assess the success of islet transplantation. Recently, we developed a simple index of islet engraftment, the secretory unit of islet transplant objects (SUITO) index. The formula is 1500 x fasting C-peptide level [ng/dL]/(fasting blood glucose levels [mg/dL]-63). A SUITO index of more than 26 was associated with insulin independence. MATERIALS AND METHODS: In this study, we compared islet engraftment efficacy using the SUITO index after a single infusion of islets from brain-dead donors into 6 recipients. We calculated the SUITO index from postoperative days 3 to 30. We compared the insulin reduction rate with the SUITO index and islet equivalent per kilogram body weight (IE/Kg). We also measured the level of glycosylated hemoglobin (HbA 1C) at 3 months posttransplantation to assess glycemic control after islet transplantation. RESULTS: In 5 cases, islets were cultured before transplantation and in 1 case they were transplanted without culture. Without culture, the SUITO index and insulin reduction rate were highest. The SUITO index significantly correlated with the insulin reduction rate (P = .031, R2 = .728), but the IE/kg was not significantly correlated (P = .303) with the rate of insulin reduction. All cases showed improved HbA 1C to the normal range. CONCLUSIONS: Immediate transplantation without culture substantially improved the efficacy of engraftment of transplanted islets. The SUITO index was a better predictor than islet mass per body weight for clinical outcomes.