Free fatty acids level may effect a residual insulin secretion in type 1 diabetes

Introduction: Recent studies on the pathogenesis of type 1 diabetes (T1DM) show that autoimmune activity in human pancreatic β-cells is accompanied by abnormalities of fatty tissue metabolism, which is the underlying process in type 2 diabetes. The aim of the study was to determine the correlation between C-peptide concentration, indicating residual insulin secretion, and free fatty acids (FFA) level in children with T1DM. Material and methods: We recruited 178 diabetic patients (mean age 10.8 years; M/F 99/79). In all individuals the fasting C-peptide by a radioimmunological method and FFA serum levels using an enzymatic colorimetric method were measured at the onset and after 6 months of the diabetes duration. Results: Thirty four (19.1%) of the patients had the C-peptide level above the lower limit of normal range (>0.28 pmol/ml) at both time points. FFA level at onset was significantly higher as compared to the level after 6 months of follow-up (38.4±?29.4 vs. 28.9±23.1 mg/dl; p=0.0003). However, both values were positively correlated (r=0.31; p=0.0008). Interestingly, a negative correlation was found between FFA and C-peptide measurements at onset (r=-0.19; p=0.01) and at 6th month of the disease (r=-0.18; p=0.02). Moreover, when the C-peptide level was treated as a binominal variable (above and below 0.28 pmol/ml) higher levels of FFA were observed in children with C-peptide deficiency at onset of diabetes (41.1 vs. 29.9 mg/dl; p=0.03) and a similar trend was noticed at 6th month of the disease (31.0 vs. 23.7 mg/dl; p=0.1). No relation of FFA with age at onset, gender, insulin requirement and HbA1c were revealed. Conclusions: The obtained results, which link the FFA level with residual insulin secretion in T1DM, may serve as further evidence supporting the contribution of fatty tissue metabolism in the pathogenesis of T1DM.