Spexin as a new metabolic biomarker in women with polycystic ovary syndrome

Abstract

Polycystic ovary syndrome (PCOS), is a common reproductive disorder with a variety of clinical manifestations such as menstrual irregularities, signs of androgen excess, and infertility but more so a multifaceted syndrome with its metabolic complications related to insulin resistance. Insulin resistance is an important feature of the syndrome that underlies many endocrine conditions and is associated with multiple metabolic disorders such as diabetes, obesity, hypertension, lipid abnormalities and cardiovascular disease. Spexin is a novel peptide, which is intensely expressed in normal human endocrine and epithelial tissues and low levels of circulating spexin levels were determined in type 2 diabetes mellitus (T2DM) subjects. Additionally, circulating spexin is reported to be inversely related to blood glucose and lipids in T2DM. Taken into consideration the potential role of spexin in glucose and lipid metabolism, we assessed serum spexin levels in women with PCOS and compared it with the controls. Since PCOS is suggested as an endocrine disorder with not only reproductive but also cardiometabolic disturbances, dealing with long term health repercussions in addition to reproductive aspects of the syndrome is important and at this point spexin could prove to be a useful marker. To our knowledge, the present study is the first in the literature that evaluates spexin levels in PCOS; however, further studies are needed. Case-control study A total of 120 women with PCOS and 50 age and body mass index (BMI) matched healthy controls were enrolled. Clinical, hormonal and metabolic parameters in addition to serum spexin levels were compared between the groups. Insulin resistance, defined by the homeostasis model assessment of insulin resistance (HOMA-IR), was calculated. Student's t-test or Mann-Whitney U-test was used for comparisons of the mean between the two groups, as appropriate. Correlation analyses were performed by using Pearson’s and Spearman’s correlation methods. Spexin levels were significantly lower in the PCOS group compared with the control (1.82±1.57 ng/ml vs 2.77±2.13 ng/ml, respectively; p<0.01). There was no statistically significant difference between the groups in terms of age, BMI, systolic and diastolic blood pressures, total cholesterol, low-density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, HOMA-IR and free androgen index. Waist to hip ratio and triglyceride levels were significantly higher in the PCOS group compared with the controls. Spexin levels were found to be positively correlated with HDL (r=0.211, p<0.05) and negatively correlated with HOMA-IR (r= -0.208, p<0.05) in women with PCOS. Women with PCOS have significantly lower serum spexin levels than the controls. Spexin levels positively correlated with HDL levels and negatively with HOMA-IR. Spexin may be a promising biomarker in women with PCOS.