Circulating levels of obestatin and copeptin in obese and nonobese women with polycystic ovary syndrome

Abstract

Objective: Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies, affecting 5-8% of reproductive-age women. It is associated with insulin resistance, central obesity, type 2 diabetes mellitus, dyslipidemia, and cardiovascular diseases. The current study was undertaken to evaluate serum copeptin and obestatin levels, carotid artery intima-media thickness, and brachial artery flow mediated dilatation in obese and nonobese women with PCOS and age-matched healthy controls and to investigate their relationship with each other and with clinical, metabolic, and hormonal parameters and cardiovascular risk factors.

Method: In the study population, we analyzed 60 patients with PCOS and 30 age-matched healthy women as controls. The patients with PCOS were divided into two groups based on body mass index (BMI): obese group (BMI>30kg/m(2), n=30) or nonobese group (BMI<30kg/m(2), n=30). History was obtained and a physical examination, peripheral venous blood sampling, and carotid and brachial artery ultrasonography were performed. Serum copeptin and obestatin levels, total testosterone, C-reactive protein (CRP), glucose, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, homeostasis model assessment for insulin resistance (HOMA-IR), carotid artery intima-media thickness (CIMT), and brachial artery flow-mediated vasodilation (FMD) were determined and compared among the groups.

Results: Women with PCOS, especially obese ones, had higher triglycerides, HOMA-IR, total testosterone, CRP, systolic and diastolic blood pressure, and waist-to-hip ratio (WHR), and lower HDL. Serum obestatin levels were significantly lower in the obese PCOS group than they were in the nonobese and control groups (p<0.001). Serum copeptin levels were significantly higher in the obese PCOS group than they were in the nonobese PCOS and control groups (p<0.001). CIMT values were similar among the groups (p>0.05). Brachial artery FMD was lower in the PCOS groups than it was in the control group (p<0.001). Obestatin and FMD values were negatively correlated with cardiovascular risk factors, whereas copeptin was positively correlated. A significant positive correlation was found between copeptin, BMI, WHR, hirsutism score, total testosterone, and HOMA-IR. There was no correlation between CIMT, copeptin, obestatin, and FMD. A positive correlation was seen between CIMT, BMI, triglycerides, and HOMA-IR.

Conclusion: Copeptin and obestatin may provide useful information regarding future cardiovascular risk in PCOS patients as copeptin was positively correlated and obestatin was negatively correlated with cardiovascular risk factors.

Keywords: Brachial artery FMD; Copeptin; Obestatin; Polycystic ovary syndrome.