The Effects And Molecular Mechanisms Of Cortisol In Endometrial Insulin Resistance In Polycystic Ovary Syndrome

AimsInsulin resistance,one of the most important pathophysiologic feature in polycystic ovary syndrome?PCOS?,not only affects systemic metabolism but also affects endometrial receptivity.Previous studies demonstrated that cortisol exaggeration closely correlated with diabetes and insulin resistance.However,the specific role of cortisol in endometrial insulin resistance has not been elucidated.This study aims to clarify the effects of cortisol in endometrial insulin resistance in PCOS and further demonstrate the molecular mechanisms of cortisol involving in endometrial insulin resistance.Methods1.We recruited patients diagnosed as PCOS according to Rotterdam consensus and further subdivided PCOS patients into PCOS without insulin resistance?IR?and PCOS with IR.Non-PCOS patients were women with regular menstrual cycles,normal body mass index?BMI 18.5-23.9 kg/m2?,and only tubal infertile conditions without IR.2.The endometrial biopsies were collected with endometrial suction curettes on seventh day after hCG injection known as the window of implantation?WOI?phase.3.Analyze the demographic features and the clinical outcomes such as implantation rate of the recruited patients.4.The cortisol and cortisone in the endometrial tissue were detected with immunoassay kits;The expression of 11?-HSD1 and 2 were detected with western blotting and PCR.5.PCR and Western blotting were used for measurement of IRS-1,p-IRS-1 Ser³⁰⁷,p-IRS-1 Ser³¹⁸,p-IRS-1 Ser⁶¹²,p-Akt Ser⁴⁷³ and PTEN;GLUT4 translocation and glucose uptake were performed in endometrial epithelial cells?EECs?to further measure the glucose uptake capacity among three groups.6.Three days after plating,EECs were treated with cortisol?1?m,24h?.Western blotting,PCR and glucose uptake were used to study the role of cortisol in the insulin signaling.7.To determine the involvement of PTEN,the PTEN inhibitor bpV?phen??1?M,Sigma?was added to EECs.Results1.The demographic characteristics and implantation outcomes showed The fasting insulin,fasting glucose,HOMA-IR,QUIKI and BMI were significantly higher in PCOS with IR patients than in non-PCOS and PCOS without IR patients.Although there was not a significant difference,there was a tendency for implantation rate in PCOS with IR women to be lower than that of non-PCOS?p=0.06?.2.No significant difference was found in the summed concentrations of cortisol plus cortisone among three groups.Concentrations of cortisol and ratios of cortisol to cortisone in PCOS with IR patients were significantly higher compared with non-PCOS and PCOS without IR patients.Concentrations of cortisone in PCOS with IR patients were lower than in non-PCOS patients,but were comparable with that in PCOS without IR patients.The quantitive detection showed an imbalanced metabolic state between cortisol and cortisone in endometria of PCOS patients especially PCOS with IR patients.3.No significant difference of 11?-HSD1 expression was found among three groups,but both mRNA and protein abundance of 11?-HSD2 in endometria of PCOS with IR patients were significantly decreased in comparison with that in non-PCOS and PCOS without IR patients.Consistently,Pearson analysis showed that 11?-HSD2was positively correlated with endometrial cortisone level but negatively correlated with endometrial cortisol level.These data suggested that the decrease in 11?-HSD2expression may account for the increased cortisol level and decreased cortisone level in endometria obtained from PCOS with IR patients.4.Total IRS-1 protein expression was lower in PCOS groups but there was not statistical significance.The phosphorylation of IRS-1 at Ser³⁰⁷,Ser³¹⁸ and Ser⁶¹² were significantly higher in PCOS with IR group compared with non-PCOS and PCOS without IR.Akt phosphorylation at Ser⁴⁷³ was significantly lower in PCOS with IR patients.Furthermore,PTEN mRNA and protein expression were significantly increased in PCOS with IR patients.These data suggested that the insulin signaling pathway was abolished in endometria of PCOS with IR patients.5.In in vitro study,cortisol attenuated insulin-stimulated glucose uptake in EECs,which was mediated by inhibition of Akt phosphorylation and GLUT4 translocation via induction of PTEN expression.6.Treatment of EECs with the PTEN inhibitor bPV?phen?rescued the cortisol-induced suppression of Akt phosphorylation as well as GLUT4 translocation.PTEN was involved in cortisol-induced attenuation of Akt phosphorylation and GLUT4 translocation.ConclusionsDecreased oxidation of cortisol and defects of insulin signaling in endometrium were observed in PCOS with IR patients.The excessive cortisol level,derived from reduction of 11?-HSD2,might contribute to the development of endometrial IR by inhibiting the insulin signaling pathway via induction of PTEN expression in EECs.