Type 2 Diabetes Mellitus Phenotype and Graft Survival After Islet Transplantation

BACKGROUND: Body fat accumulation decreases insulin sensitivity. It has being associated with earlier onset of type 1 diabetes mellitus (DM) and islet graft failure. The aim of this study was to evaluate whether insulin resistance, characterized by risk factors for type 2 diabetes mellitus (DM), can predict islet graft survival in type 1 DM islet transplant (ITx) recipients. METHODS: Demographic, anthropometrical and laboratory data, as well as family history of type 2 DM (first degree relatives), were collected from 44 ITx recipients. Risk factors for type 2 DM, such as positive family history of type 2 DM (n=11) and overweight (BMI >25 kg/m(2); n=14), were analyzed separately and in combination, which was designated as “type 2 DM phenotype” (n=5). Differences in outcomes (time-to-graft dysfunction and failure) were compared using Kaplan-Meier curves. Cox-regression analysis was performed to control for possible confounding factors. RESULTS: Neither positive family history of type 2 DM nor overweight at baseline could predict islet function outcomes after ITx. However, when both risk factors were grouped, the “type 2 DM phenotype” was associated with earlier islet graft failure (mean estimate graft survival 25.7±9.1 vs. 54.1±5.2 months, P=0.022). These results were sustained after adjustments for confounding variables (OR5.20, 95%CI1.12-24.0). CONCLUSIONS: Predisposition for type 2 DM can coexist with the type 1 DM phenotype and is associated with earlier decline in islet graft function. Prospective clinical trials should address whether it is associated with decreased insulin sensitivity and if insulin sensitizers play a role in prolonging islet graft survival

Liver fat accumulation after islet transplantation and graft survival

Our objective is to evaluate if there is an association between liver fat accumulation after islet transplantation (ITx) and graft survival. A cohort study was conducted in 34 subjects with type 1 diabetes postallogeneic ITx. Liver fat content was evaluated by magnetic resonance imaging (MRI) (change in liver signal intensity on inphase and opposed-phase images). Kaplan–Meier curves and Cox regression analysis were performed with islet dysfunction duration as the dependent variable and fat liver content as an independent one. Values of p < 0.05 were significant (SSPS®18.0 and MedCalc®12.5). Patients’ mean age was 40 ± 8 years (diabetes duration: 31 ± 12 years; male: 41%). Islet survival did not differ in patients without (51 months, 95% CI 40–62 months) or with steatosis (48 months, 95% CI 38–58 months; p = 0.55) during islet dysfunction period. Nevertheless, survival curves appear to separate late in the follow-up, and after 40 months steatosis was associated with shorter graft survival (p log rank = 0.049). This association remained (RR 23.5, 95% CI 1.1–516.0; p = 0.045) after adjustments for possible confounding factors. In this sample of subjects with type 1 diabetes submitted to ITx, steatosis was not associated with islet failure in the whole cohort. However, in subjects with functional islets after 40 months, a shorter graft survival was observed in those with steatosis during the islet dysfunction period, even after adjustments to variables known to be associated with islet failure

Liver fat accumulation after islet transplantation and graft survival

Our objective is to evaluate if there is an association between liver fat accumulation after islet transplantation (ITx) and graft survival. A cohort study was conducted in 34 subjects with type 1 diabetes postallogeneic ITx. Liver fat content was evaluated by magnetic resonance imaging (MRI) (change in liver signal intensity on inphase and opposed-phase images). Kaplan–Meier curves and Cox regression analysis were performed with islet dysfunction duration as the dependent variable and fat liver content as an independent one. Values of p < 0.05 were significant (SSPS®18.0 and MedCalc®12.5). Patients’ mean age was 40 ± 8 years (diabetes duration: 31 ± 12 years; male: 41%). Islet survival did not differ in patients without (51 months, 95% CI 40–62 months) or with steatosis (48 months, 95% CI 38–58 months; p = 0.55) during islet dysfunction period. Nevertheless, survival curves appear to separate late in the follow-up, and after 40 months steatosis was associated with shorter graft survival (p log rank = 0.049). This association remained (RR 23.5, 95% CI 1.1–516.0; p = 0.045) after adjustments for possible confounding factors. In this sample of subjects with type 1 diabetes submitted to ITx, steatosis was not associated with islet failure in the whole cohort. However, in subjects with functional islets after 40 months, a shorter graft survival was observed in those with steatosis during the islet dysfunction period, even after adjustments to variables known to be associated with islet failure