Relation of fasting plasma peptide YY to glucose metabolism and cardiovascular risk factors after restrictive bariatric surgery

INTRODUCTION: Surgically induced weight loss results in reduction of comorbidities in severely obese humans. Reversal of abnormal secretion of appetite-regulating gut hormones such as peptide YY (PYY) could be contributing to the improvement of cardiovascular risk factors. METHODS: Severely obese patients (n = 42, BMI = 45.7 +/- 5.3 kg/m(2)) underwent clinical examination and blood sampling for measurement of PYY, plasma lipids, oral glucose tolerance testing and assessment of insulin secretion (HOMA-%B) and action (HOMA-R, QUICKI) before and during 12 months following gastric banding. Comparisons were made at each time point of the study as well as across the total study period. RESULTS: Weight loss after bariatric surgery resulted in improvement of insulin resistance by 54% (p < 0.03) and plasma triglycerides by 26% (p < 0.01) without changes in fasting PYY (16.2 +/- 8.7 pmol/l at baseline, 15.1 +/- 6.3 pmol/l at 12 months). Fasting PYY correlated negatively with plasma total cholesterol at baseline (p = 0.02) but was not associated with body weight, body mass or abdominal diameter. Individual changes in PYY (Delta PYY) related to changes in insulin (Delta fasting insulin) at 12 months (r = -0.582, p = 0.02) and HOMA-B at 6 months (r = -0.677, p = 0.006) and 12 months (r = -0.660, p = 0.007). Diabetic status had no impact on these correlations. DISCUSSION: PYY correlates with a major cardiovascular risk factor and surrogate parameters of insulin secretion but not to weight loss or body mass in severe obesity.