Interpretation
As we all know, Polycystic ovary syndrome (PCOS) is a highly heterogeneous endocrine disorder characterized by hyperandrogen, rare ovulation and polycystic ovary, and its pathogenesis is debated14-16.Previous studies have demonstrated that the core etiology and primary endocrine characteristics of PCOS are insulin resistance (IR) and hyperandrogenemia (HA), and they can interplay each other leading to metabolic syndrome, especially dyslipidemia17-21. AMH are often used as clinical observation indicators reflecting the ovarian reserve22,23, and the LH/FSH and T levels were significantly higher in PCOS patients compared with control patients24,25.Compared with those characteristics related to PCOS, the expression level of ANGPTL4 in ovarian GCs might be a independent factor which affected incidence of PCOS and could serve as a new predictor for PCOS according to results of ROC cure and binary logistic regression analysis.
As a member of angiopoietin-like proteins (Angptls) family, ANGPTL4 has been extensively investigated, reporting its involvement in physiological and pathological conditions including energy metabolism, tumorigenesis, vascular homeostasis, and inflammation26-30. One of the extensively investigated roles of ANGPTL4 is its role in lipid metabolism, specifically regulating LPL activity to clear triglycerides (TG) from the circulation8.In addition, a recent study demonstrated that ANGPTL4 knock out mice markedly improved glucose tolerance with increased insulin levels31.Güneş M et al10 revealed that there was a significant increase in level of serum ANGPTL4 compared to control women and IR was significantly associated with ANGPTL4 concentrations in patients. Those were corresponding to the result in our study that the ANGPTL4 expression in ovarian GCs was positively correlated with HOMA-IR, as well as related to lipid metabolic characteristics such as LDL/HDL, ApoB/ApoAI and TC/HDL. In view of the finding of our study, ANGPTL4 might participant in the glucose and lipid metabolism in the ovarian surroundings, which might affect the occurrence and development of PCOS. In addition, ANGPTL4 also acts as an apoptosis survival factor for vascular endothelial cells. It plays a key role in the late stages of folliculogenesis and participant in providing oxygen and nutrients to growing follicles 32,33. Our study showed the positively correlation between ANGPTL4 expression and AMH, and indicated its possible impact on follicular development. All of our findings were preliminary, more mechanisms research are still expected.
High expression of ANGPTL4 in ovarian GCs with PCOS and its strongly association with multiple glucose and lipid metabolism characteristics suggests that ANGPTL4 expression level might play an important role in pathogenesis and development of PCOS, and could offer a granulosa-cell–derived marker for PCOS prediction. Our findings also raise serious of important new questions. What is mechanism of ANGPTL4 expression in PCOS? What is the role of ANGPTL4 signaling for metabolism in the ovarian GCs? All these questions have not yet been reported.