Potential markers of insulin resistance in healthy vs obese and overweight subjects.

BACKGROUND Insulin resistance can lead to the metabolic syndrome, which may have cardiovascular and metabolic consequences. The study aimed at verifying the serum concentration levels of the adipose tissue proteins adiponectin, adipocyte-fatty acid binding protein (a-FABP) and acylation stimulating protein (ASP), and the potential use of these markers for early diagnosis of insulin resistance. METHODS AND RESULTS Healthy subjects (Group A, n = 53), overweight subjects (Group B, n = 29) and obese subjects (Group C, n = 51) were studied. Those in Groups B and C had symptoms of insulin resistance. The subjects were selected based on clinical and laboratory findings. The concentrations of adiponectin were highest in the healthy subjects in Group A (14.18 ± 6.99 mg/), lower in the overweight subjects in Group B (11.12 ± 4.46 mg/l) and lowest in the obese subjects in Group C (8.15 ± 2.70 mg/l). The a-FABP values were lowest in Group A (20.23 ± 7.95 mg/l), higher in Group B (32.22 ± 15.56 mg/l) and highest in Group C (40.43 ± 23.31 mg/l). The concentrations of ASP were lowest in the Group A healthy subjects (43.01 ± 22.78 nmol/l), higher in the Group B overweight subjects (50.58 ± 25.57 nmol/l) and highest in the Group C obese subjects (54.70 ± 26.41 nmol/l). Statistically significant correlation coefficients in subjects from all groups among the markers studied describe the highest correlation is between a-FABP and BMI (r = 0.48), adiponectin and QUICKI (r = 0.42), adiponectin and triacylglycerols (r = -0.35), ASP and BMI (r = 0.33) and adiponectin and BMI (r = -0.31). CONCLUSIONS The concentrations of all studied markers were different in the healthy subjects as compared to the overweight or obese ones. Adiponectin proved to be a good indicator of insulin sensitivity, the low concentration of which could signal the initial stage of insulin resistance. A-FABP proved to be a prominent marker of "adiposity" in association with the development of insulin resistance. ASP did not prove to show significant differences between the overweight and healthy subjects, but significant differences were found between the obese and healthy subject.