Effects of short-term calorie restriction on circulating DPP-4/sCD26 concentrations and body composition in patients with type 2 diabetes

Previous studies have shown that dipeptidyl peptidase (DPP)-4, is released from adipocytes in a differentiation-dependent manner and a marker for insulin resistance in obese individuals who have particularly high circulating DPP-4/soluble CD26 (sCD26) concentrations. In this study, we have evaluated the effects of short-term hospitalization with calorie restriction on body composition and circulating DPP-4/sCD26 concentrations in patients with type 2 diabetes. A total of 47 Japanese adults with type 2 diabetes were recruited to the study (age; 56.6 +/- 13.0 years, body mass index (BMI); 27.3 +/- 5.6 kg/m(2)). Body composition, circulating DPP-4/sCD26 concentrations and metabolic parameters were assessed upon admission and at discharge from hospital (average of the period: 13.0 +/- 2.5 days). Visceral fat area (VFA) was also assessed by dual impedance method. During hospitalization, there was a significant reduction in body weight, BMI, lean body mass, VFA and circulating DPP-4/sCD26 concentrations, but not in body fat mass. Fasting circulating DPP-4/sCD26 concentrations were significantly correlated with fasting insulin, aspartate aminotransferase, gamma-glutamyltransferase (gamma-GTP) levels, and HOMA-IR (r = 0.477, 0.423, 0.415, 0.548, respectively), but not with VFA (r = - 0.056) by liner regression analyses at base line. It was also observed a positive correlation between changes in circulating DPP-4/sCD26 concentrations and gamma-GTP level, HOMA-IR, and a negative correlation between the changes in circulating DPP-4/sCD26 concentrations and VFA significantly (r = 0.300, 0.633, - 0.343, respectively). In conclusion, our observations suggest that liver enzymes as well as VFA might be associated with the response of DPP-4/sCD26 concentrations.