Association between circulating neuregulin 4 levels and metabolic, aterogenic, and AMH profile of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a metabolic disorder associated with obesity and energy metabolic system disturbances in adipose tissue. Neuregulin 4 (NRG4), which is secreted by adipose tissue, regulates energy metabolism. In the present study, we aimed to evaluate the association between serum NRG4 levels in obese and normal weight PCOS patients. This cross-sectional study was conducted at a tertiary hospital in Turkey from April to August 2017. We included 148 women who were divided into four groups as follows: 40 normal weight and 39 obese PCOS women diagnosed according to the Rotterdam criteria as well as 38 normal weight and 31 obese, age-matched, non-hyperandrogenemic women with a regular menstrual cycle (controls). Levels of serum NRG4, anti-Müllerian hormone (AMH), fasting blood glucose (FBG), insulin, and high-sensitivity C-reactive protein (hs-CRP); lipid and hormone profiles; insulin resistance indices [homeostasis model assessment of insulin resistance (HOMA-IR)];and anthropometric parameters were evaluated. Serum NRG4 levels were elevated in the normal weight PCOS group than in the control group. Moreover, serum NRG4 levels were higher in the obese PCOS group than in the normal weight PCOS and obese control groups (p < .01). Serum NRG4 levels were positively correlated with body mass index (BMI); waist/hip ratio; HOMA-IR; and levels of triglycerides, hs-CRP, FBG, insulin, AMH, and dehydroepiandrosterone sulphate. Multiple regression analyses revealed that serum NRG4 levels were independently associated with BMI. Obesity appears to be the most influential factor for NRG4 secretion in PCOS patients. Management of obesity may be a key factor for resolving PCOS-related metabolic abnormalities and fertility problems. Impact Sstatement What is already known on this subject? PCOS is a dynamic syndrome with different clinical and metabolic features during the reproductive age. PCOS is associated with various metabolic abnormalities, such as insulin resistance (IR), glucose intolerance, dyslipidemia, and obesity (particularly visceral obesity) as well as long-term complications, such as type 2 diabetes and cardiovascular diseases. Neuregulin 4 (NRG4), which is secreted by adipose tissue, regulates energy metabolism. What do the results of this study add? To the best of our knowledge, this was the first study investigating NRG4 levels in PCOS patients with different BMIs. Obesity appears to be the most influential factor for NRG4 secretion in these patients. Managing obesity may be a key factor for resolving PCOS-related metabolic abnormalities. What are the implications of these findings for clinical practice and/or further research? Further research in PCOS is warranted to ameliorate obesity, and our study can provide basis for future studies investigating NRG4 levels in PCOS patients with different phenotypes as well as studies of gene polymorphisms, AMH, and infertility and can contribute to the elucidation of problems related to the pathophysiology of PCOS.