ESPEN 2011 Late breaking abstract submission

Topic: Late Breaking Abstract

Abs n°:ESPEN11-2073

Abs Title: UPPER-BODY OBESE WOMEN ARE RESISTANT TO POSTPRANDIAL STIMULATION OF PROTEIN SYNTHESIS

F. Liebau ^1,*M. D. Jensen ²K. Sreekumaran Nair ²O. Rooyackers ³

¹Dept of Anaesthesiology and Intensive Care, Huddinge, Karolinska University Hospital, Stockholm, Sweden, ²Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota, United States, ³CLINTEC, Karolinska Institute, Stockholm, Sweden

Rationale: Upper-body, i.e. visceral, obesity is associated with insulin resistance and impaired protein synthesis. We analysed the postprandial response of protein metabolism in a cohort of obese women whose fatty acid kinetics were reported previously (Guo et al. 1999).

Methods: Subjects were studied after an overnight fast and after a mixed meal, grouped as upper-body (UB) obese (waist-to-hip ratio, WHR, >0.85, n=6) vs. lower-body (LB) obese (WHR<0.80, n=7). Body fat distribution was evaluated by dual energy X-ray absorptiometry and single-slice computed tomography. Plasma free fatty acids (FFA) were analysed by HPLC, and fasting plasma insulin and glucose concentrations were used to calculate the Quicki index, a measure of insulin sensitivity. Stable isotope labeled phenylalanine was administered intravenously and orally, and phenylalanine/tyrosine isotopic enrichments in femoral arterial and venous blood were measured by mass spectrometry. Muscle and whole-body protein breakdown and synthesis were calculated using equations for steady-state kinetics. Groups were compared by t-test, and values are presented as mean±SD.

Results: UB subjects had more visceral fat (p<0.01) and higher fat-free body mass (p=0.02), while body-mass index was similar to LB. At baseline, UB had higher plasma insulin (94±26 vs. 46±13 pmol/L, p<0.01), were less insulin sensitive (Quicki=0.32±0.01 vs. 0.36±0.02, p<0.01), and had higher plasma FFA (777±102 vs. 629±92 μmol/L, p=0.02). Protein balance was similarly negative (-6.5±2.4 vs. -7.6±0.9 μmol/kg/h, p=0.27). Postprandially, UB had more distinct hyperinsulinemia (493±171 vs. 290±106 pmol/L, p=0.02), FFA remained higher (252±116 vs. 74±36 μmol/L, p<0.01) and protein balance became less positive (14.8±3.7 vs. 20.2±3.7 μmol/kg/h, p=0.02).

Conclusion: Postprandial stimulation of protein synthesis and suppression of lipolysis is impaired in upper-body obese women.

Reference(s): Guo et al. 1999, Diabetes 48:1586-92

Disclosure of Interest: None Declared

Keywords: Obesityprotein metabolism