Ghrelin PYY 3-36 serum changes in left ventricular hypertrophic, insulin-resistant, hypertensive obese patients

Aim: Hypertension is a major health problem and is usually associated with common conditions such as obesity, which contribute to clinical cardiac dysfunction. The role of energy homeostasis hormones such as ghrelin and PYY 3-36 in cardiovascular function remains incompletely understood. Therefore, the aim of our study was to explore the potential differences in concentrations of ghrelin forms and PYY 3-36 circulating in obese patients with grade 1 and grade 2 hypertension, with higher and lower BMI and without and with insulin resistance as well as to determine whether these hormones may be associated with left ventricular hypertrophy.

Methods: A total of 142 adult subjects were studied in three subgroups: lean (BMI < 25 kg/m(2)) normotensive subjects and obese subjects (BMI 30.0-34.9 kg/m(2)), and obese subjects (BMI 35.0-39.9 kg/m(2)) under hypertensive treatment for at least 9 years. Fasting blood glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), lipid profile, urinic acid, acylated ghrelin (A-Ghr), total ghrelin (T-Ghr), and PYY 3-36 were measured. Insulin resistance was determined by the homeostasis model assessment of insulin resistance (HOMA-IR). We also echocardiographically assessed left ventricular mass (LVM) index (LVMI = LVM/height(2.7)). We evaluated the association between plasma T-Ghr, A-Ghr, PYY 3-36 levels with LVMI and other measured factors using univariate and multivariate analysis.

Results: There were significant differences between BMI, waist circumference (WC), LVMI, hs-CRP and A-Ghr/nonacylated ghrelin (NA-Ghr) ratio (in the two obese subgroups. There was no significant difference between T-Ghr, A-Ghr and PYY 3-36 levels between obese subgroups. T-Ghr and PYY 3-36 were significantly lower in obese patients than in the control group, whereas A-Ghr levels did not differ between obese and controls. A-Ghr/NA-Ghr ratio was significantly higher in patients with second-degree hypertension and BMI 35.0-39.9 kg/m(2) than in patients with first-degree hypertension and BMI 30.0-34.9 kg/m(2). There were negative associations between T-Ghr, NA-Ghr or PYY 3-36 and LVMI (r = -0.49, p = 0.0001; r = -0.47, p = 0.0001; or r = -0.18, p = 0.029, respectively) and positive association between A-Ghr/NA-Ghr ratio and LVMI (r = 0.3, p = 0.0003). T-Ghr and NA-Ghr, were associated negatively with fasting insulin (r = -0.31, p = 0.0025; and r = -0.36, p = 0.001, repectively), while A-Ghr/NA-Ghr ratio was positively associated with BMI and fasting insulin (r = 0.23, p = 0.041; r = 0.3, p = 0.0045, respectively). T-Ghr, A-Ghr, and NAGhr were also inversely related to HOMA-IR indices in obese patients (r = -0.43, p = 0.001; r = -0.32, p = 0.0359; r = -0.35, p = 0.001, respectively). In insulin-resistant obese subjects T-Ghr and NA-Ghr correlated negatively with HOMA-IR (r = -0.34, p = 0.0015; r = -0.28, p = 0.0116, respectively). LVMI was associated negatively with T-Ghr, NA-Ghr and PYY 3-36 (r = -0.49, p = 0.0001; r = -0.47, p = 0.0001; r = -0.18, p = 0.029, respectively). In addition, LVMI was positively associated with A-Ghr/NA-Ghr ratio (r = 0.30, p = 0.0003).

Conclusion: Plasma ghrelin forms and PYY 3-36 levels are associated with LVMI. These associations indicate a possible interaction between gut peptides and the cardiovascular system in hypertension and obesity.