OBJECTIVES: The influence of body fat reduction on adipocyte fatty acid-binding protein (A-FABP) in obese patients with type 1 diabetes mellitus (T1DM) was investigated to examine whether it relates to the etiopathogenesis of insulin resistance (IR) and obesity. METHODS: We studied 14 obese patients with T1DM and IR (42.6±9.4 years, BMI 32.4±2.1 kg/m2) and 13 non-obese control patients with T1DM (36.9±13.9 years, BMI 22.6±2.1 kg/m2). Plasma FABP was measured by ELISA and plasma free fatty acids (FFA) were measured spectrophotometrically before weight reduction, immediately after 7 days of fasting and after 21 days on a low-calorie diet. The control group was studied only after overnight fasting. Body composition was examined using bioimpedance spectroscopy. The means ± SD, T-test, one-way ANOVA and Spearman's correlation were used for statistical evaluation. RESULTS: All patients tolerated the period of fasting. Obese T1DM patients lost 6.1±1.1 kg. There was a significant decrease in body mass index and body fat measured 21 days after weight reduction (p<0.05). Plasma FABP and FFA concentrations in obese T1DM patients before weight reduction were significantly higher than in controls, further increased significantly after fasting (p<0.05) and were restored thereafter. Significant positive correlations between FABP and FFA and between FABP and BMI (p<0.05) were found. CONCLUSION: Increased plasma FABP indicates insulin resistance in obese patients with T1DM. Weight reduction in T1DM patients is associated with a desirable decrease of body fat and transiently increased FABP. This increase might be a temporary adaptation of metabolism to non-stress fasting.

3rd Department of Medicine Metabolic Care and Gerontology Charles University in Hradec Králové Czech Republic