Effect of exercise training on A-FABP, lipocalin-2 and RBP4 levels in obese women

Objective Lipocalin family proteins, including adipocyte fatty acid-binding protein (A-FABP), lipocalin-2 and retinol-binding protein 4 (RBP4), have recently been identified as novel adipokines associated with obesity, type 2 diabetes and the metabolic syndrome. We have evaluated the effect of exercise training on lipocalin family proteins and inflammatory markers. Study subjects Thirty obese Korean women and 15 age-matched nonobese control subjects were studied. Design Concentrations of the lipocalin family proteins were compared between obese and nonobese women and were evaluated before and 3 months after an exercise programme consisting of aerobic exercise (45 min/session, 300 kcal/day) and muscle strength training (20 min/session, 100 kcal/day) five times a week. Results Obese women exhibited higher A-FABP levels compared to nonobese women (21·4 ± 6·4 μg/l vs. 13·6 ± 4·4 μg/l, P < 0·001). However, neither lipocalin-2 nor RBP4 levels were significantly different between the two groups, although the difference in lipocalin-2 was marginally significant (P = 0·054). Circulating A-FABP levels were significantly associated with body mass index (BMI), waist circumference, triglyceride, alanine aminotransferase (ALT), lipocalin-2 and high-sensitivity C-reactive protein (hsCRP) levels. After 3 months of the exercise training programme, serum A-FABP levels decreased significantly from 21·4 ± 6·4 μg/l to 19·3 ± 6·8 μg/l (P = 0·038), along with a reduction in weight, BMI, waist circumference, fasting glucose and total cholesterol levels. There was no significant change in the lipocalin-2 and RBP4 levels, although IL-6 levels increased after the exercise programme. Conclusion Exercise training with weight loss induced a significant reduction in circulating A-FABP levels in obese Korean women.