Prediction of Insulin Resistance and Impaired Fasting Glucose Based on Sex Hormone-Binding Globulin (SHBG) Levels in Polycystic Ovary Syndrome

Body mass index is a good predictor of metabolic abnormalities in polycystic ovary syndrome

AIM

To assess which parameters among hyperandrogenism (total testosterone-tT-or free androgen index-FAI), sex hormone binding globulin (SHBG) or body mass index (BMI) could better predict a worse metabolic profile in women with polycystic ovary syndrome (PCOS).

METHODS

Five hundred and eighty-six women with PCOS and clinical or biochemical hyperandrogenism were included. Receiver Operating Characteristics (ROC) curves with tT, FAI, SHBG and BMI were performed for metabolic parameters and a cut-off with sensitivity and specificity was obtained for each parameter. The women were then divided into three groups and compared according to their BMI.

RESULTS

Based on the ROC curves, tT proved not to be a good predictor of metabolic alterations. FAI and SHBG resulted to be good predictors of some markers of metabolic damage. The area under the curves (AUC) of SHBG were greater than those of FAI. SHBG levels affects the values of homeostasis model assessment of insulin resistance (HOMA-IR), fasting insulin, high density lipoproteins (HDL), low density lipoproteins (LDL), and total cholesterol also when corrected for BMI. However, the highest AUCs of the ROC curves were observed when BMI was used, which was significantly related to all the metabolic parameters analyzed. Dividing women according to their BMI, BMI between 25.00 and 30.00 kg/m2 had a worse metabolic profile but still in a normal range, while BMI ≥ 30 kg/m2 women had a significant metabolic derangement.

DISCUSSION

BMI is a good predictor factor of metabolic changes in PCOS women at any age, and obesity is associated to the appearance of metabolic complications. Overweight and obese PCOS women should be addressed to perform a complete metabolic assessment.

Sex Hormone Binding Globulin is an Independent Predictor for Insulin Resistance in Male Patients with Newly Diagnosed Type 2 Diabetes Mellitus

INTRODUCTION

This study explored the correlation between sex hormones, sex hormone binding globulin (SHBG), and insulin resistance in male patients with newly diagnosed type 2 diabetes mellitus (T2DM).

METHODS

A total of 48 male patients with newly diagnosed T2DM were enrolled in this study between March 2022 and December 2022. Clinical characteristics, sex hormones, and SHBG levels were collected. All enrolled subjects received intensive hypoglycemic treatment with insulin pump for 1 week to achieve glycemic control, then the steady-state glucose infusion rate (GIR), an indicator of insulin sensitivity, was determined by the hyperinsulinemic-euglycemic clamp. Correlation analysis and multivariate logistic regression analysis were performed to explore the association of clinical characteristics, sex hormones, and SHBG with insulin sensitivity. The optimal cutoff value to predict insulin resistance was calculated using receiver operating characteristic (ROC) curve.

RESULTS

According to the GIR cut-point value of 5.700 mg/(kg min), there were 40 patients with insulin resistance (IR group) and 8 patients without (non-IR group). The IR group exhibited lower testosterone and SHBG levels than the non-IR group (all p < 0.050). Correlation analysis showed that insulin sensitivity was positively associated with testosterone and SHBG, while negatively associated with body mass index, fasting blood glucose, alanine aminotransferase, aspartate aminotransferase, total cholesterol, triglyceride, and apolipoprotein B (all p < 0.050). Multivariate logistic regression analysis demonstrated that SHBG is an independent predictor for insulin resistance (p = 0.029). Further ROC curve analysis revealed that the optimal cutoff value of SHBG to predict insulin resistance is 17.200 nmol/L, with the corresponding area under the curve (AUC) and its 95% confidence interval (CI) being 0.813 and 0.691-0.934.

CONCLUSIONS

SHBG is an independent predictor for insulin resistance in male patients with newly diagnosed T2DM.

TRIAL REGISTRATION NUMBER

KY20220314-01.

Pioglitazone can improve liver sex hormone-binding globulin levels and lipid metabolism in polycystic ovary syndrome by regulating hepatocyte nuclear factor-4α

Polycystic ovary syndrome (PCOS) is a common reproductive and metabolic disorder that is closely correlated with insulin resistance. Sex hormone-binding globulin (SHBG) is an important carrier for regulating androgen activity and is affected by insulin level, which is related to metabolic abnormalities and long-term prognosis of PCOS. Insulin sensitizer pioglitazone can improve the SHBG level and dyslipidaemia in PCOS, but the mechanism remains unclear. We investigated liver SHBG expression, liver lipid levels, and the effects and potential mechanisms of pioglitazone on reproductive and metabolic disorders in a rat model of polycystic ovary syndrome with insulin resistance (PCOS-IR). PCOS-IR was induced by letrozole and a high-fat diet. Metformin was used as a positive control. Additionally, dihydrotestosterone and oleic acid combined with palmitic acid were used to induce the HepG2 cell models with IR. The cells were exposed to pioglitazone alone or in combination with a hepatocyte nuclear factor (HNF)- 4α inhibitor. Changes in biochemical characteristics were analysed using an enzyme-linked immunosorbent assay. Vaginal smears were used to analyse the oestrous cycle, and ovarian histology was used to analyse the changes in ovarian morphology. The degree of IR in vivo and in vitro was measured using the hyperinsulinaemic-euglycaemic clamp and glucose oxidase techniques. The levels of key anabolism-related proteins, including SHBG, HNF-4α, and peroxidase proliferator-activated receptor (PPAR-γ), were measured using western blots. Pioglitazone and metformin significantly increased the SHBG levels in the sera and livers. Compared to metformin, pioglitazone significantly improved the lipid droplet deposition, triglyceride (TG) and total cholesterol (TC) levels, HNF-4α protein expression, and weights of the livers in the PCOS-IR rats. After applying pioglitazone with an HNF-4α inhibitor in the PCOS-IR cell models, we found that pioglitazone may increase SHBG and improve IR, TG, and TC levels by upregulating HNF-4α. Similar to metformin, pioglitazone also restored the oestrous cycle and ovarian morphology, ameliorated IR and hyperandrogenaemia in the PCOS-IR rats. Our findings hint at the value of HNF-4α in the treatment of PCOS by PIO, which could shed light on potential targets that may be used in treatments for PCOS with metabolic disorders.

Current Perspectives on Nonalcoholic Fatty Liver Disease in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common reproductive, endocrine, and metabolic disorders in premenopausal women. Clinically, PCOS is mainly caused by androgen excess and ovarian dysfunction, manifested by anovulatory menstrual cycles, infertility, and hirsutism. In addition, PCOS increases the risk of insulin resistance, obesity, cardiovascular disease, anxiety and depression, dyslipidemia, and endometrial cancer. Nonalcoholic fatty liver disease (NAFLD) is defined as ≥5% fat accumulation in the liver in the absence of remaining secondary causes and has become one of the most common chronic liver diseases worldwide. The prevalence of NAFLD is significantly higher and more severe in women with PCOS, and its pathogenesis can be associated with various risk factors such as hyperandrogenemia, insulin resistance, obesity, chronic low-grade inflammation, and genetic factors. Although there is no definitive solution for the management of NAFLD in PCOS, some progress has been made. Lifestyle modification should be the basis of management, and drugs to improve metabolism, such as insulin sensitizers and glucagon-like peptide-1 agonists, may show better efficacy. Bariatric surgery may also be a treatment of NAFLD in obese women with PCOS. This paper reviews three aspects of prevalence, risk factors, and management, in order to better understand the current state of research on NAFLD in PCOS, to explore the pathogenesis of NAFLD in PCOS, and to encourage further research on the application of drugs in this field.