ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2008) 16 P505

Plasma osteopontin correlates with insulin resistance in obese subjects, but increases following bariatric surgery parallel to other markers of bone turnover

Michaela Riedl1, Greisa Vila1, Christina Maier1, Ammon Handisurya1, Soheila Shakeri-Manesch2, Gerhard Prager2, Oswald Wagner3, Alexandra Kautzky-Willer1, Martin Clodi1 & Anton Luger1

1Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria; 2Division of General Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria; 3Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Vienna, Vienna, Austria.

Osteopontin (OPN) is a multifunctional glycoprotein implicated, among others, in bone metabolism, cardiovascular disease, diabetes and obesity. It promotes inflammation and insulin resistance. Osteopontin is elevated in the plasma and adipose tissue of obese subjects and decreases upon diet induced weight loss. Here we investigated the effect of bariatric surgery on plasma OPN concentrations in morbidly obese patients. 40 obese patients aged 43.1±1.8 years were recruited from the cohort scheduled to undergo bariatric surgery. Roux-en-Y gastric bypass (RYGB) was performed in 30 subjects (27 females, 3 males), and laparoscopically adjustable gastric banding (LAGB) in 10 subjects (8 females, 2 males). All patients were studied before and one year (10.3 to 14.8 months) after the surgical intervention. Prompted by the associations of OPN with both bone metabolism and metabolic diseases, we explored the changes in metabolic, inflammatory and bone turnover parameters. Both bariatric procedures significantly reduced body weight, body mass index (BMI), insulin, leptin and CRP one year after surgery. Plasma OPN increased from 31.38±3.8 to 52.81±3.7 ng/ml after RYGB (P<0.001) and from 29.76±6.9 to 46.4±10.6 ng/ml after LAGB (P=0.042). Preoperative OPN correlated with age, insulin, HOMA insulin resistance index and postoperative OPN. Postoperative OPN correlated with C-telopeptide and OC. In summary, plasma OPN levels significantly rise and correlate with biomarkers of bone turnover one year after RYGB and LAGB. Unlike other pro-inflammatory cytokines, OPN does not normalize, but further increases after bariatric surgery.