White, brown, and bone marrow adipose tissue behavior in DHEA-induced PCOS mice

Decreased AMPK/SIRT1/PDK4 induced by androgen excess inhibits human endometrial stromal cell decidualization in PCOS

Polycystic ovary syndrome (PCOS) is a complex common endocrine disorder affecting women of reproductive age. Ovulatory dysfunction is recognized as a primary infertile factor, however, even when ovulation is medically induced and restored, PCOS patients continue to experience reduced cumulative pregnancy rates and a higher spontaneous miscarriage rate. Hyperandrogenism, a hallmark feature of PCOS, affects ovarian folliculogenesis, endometrial receptivity, and the establishment and maintenance of pregnancy. Decidualization denotes the transformation that the stromal compart of the endometrium must undergo to accommodate pregnancy, driven by the rising progesterone levels and local cAMP production. However, studies on the impact of hyperandrogenism on decidualization are limited. In this study, we observed that primary endometrial stromal cells from women with PCOS exhibit abnormal responses to progesterone during in vitro decidualization. A high concentration of testosterone inhibits human endometrial stromal cells (HESCs) decidualization. RNA-Seq analysis demonstrated that pyruvate dehydrogenase kinase 4 (PDK4) expression was significantly lower in the endometrium of PCOS patients with hyperandrogenism compared to those without hyperandrogenism. We also characterized that the expression of PDK4 is elevated in the endometrium stroma at the mid-secretory phase. Artificial decidualization could enhance PDK4 expression, while downregulation of PDK4 leads to abnormal decidualization both in vivo and in vitro. Mechanistically, testosterone excess inhibits IGFBP1 and PRL expression, followed by phosphorylating of AMPK that stimulates PDK4 expression. Based on co-immunoprecipitation analysis, we observed an interaction between SIRT1 and PDK4, promoting glycolysis to facilitate decidualization. Restrain of AR activation resumes the AMPK/SIRT1/PDK4 pathway suppressed by testosterone excess, indicating that testosterone primarily acts on decidualization through AR stimulation. Androgen excess in the endometrium inhibits decidualization by disrupting the AMPK/SIRT1/PDK4 signaling pathway. These data demonstrate the critical roles of endometrial PDK4 in regulating decidualization and provide valuable information for understanding the underlying mechanism during decidualization.

Marrow adipose tissue is increased in overweight and obese women with PCOS independently of hyperandrogenism related obesity and metabolic disorders

Purpose

This study aimed to investigate the increase in bone marrow adipose tissue (BMAT) in overweight and obese women with polycystic ovary syndrome (PCOS) and its relationship with hyperandrogenism, obesity, and metabolic disorders.

Methods

The study included 87 overweight or obese women with PCOS (mean age 29 ± 4 years), as well as 87 age-matched controls recruited from a separate population study. All PCOS patients were measured for anthropometric features, abdominal adipose tissue areas, BMAT, biochemistry, and sex hormones. BMAT was compared between the PCOS patients and controls. In PCOS patients, subgroup comparisons of BMAT and its associations with body adiposity indices, biochemistry, and sex hormones were analyzed. The odds ratios (ORs) of elevated BMAT (defined as BMAT ≥ 38%) were calculated.

Results

On average BMAT was increased by 5.6% ( ± 11.3%) in PCOS patients compared to controls. BMAT were significantly higher in the upper tertiles of total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-C). BMAT was not correlated with abdominal adiposity indices or biochemistry except for LDL-C (r = 0.253-0.263, p = 0.014-0.018). LDL-C was not significantly different between the normal and abnormal androgen PCOS subgroups (p = 0.10-0.887). LDL-C, follicle stimulating hormone (FSH), and total testosterone (TT) were risk factors for elevated BMAT, with ORs of 1.899 (p = 0.038-0.040), 1.369 (p = 0.030-0.042), and 1.002 (p = 0.040-0.044) for each unit increase, respectively.

Conclusion

BMAT was increased in overweight and obese PCOS patients, but the increase in BMAT was not associated with the hyperandrogenism related obesity or metabolic disorders.

Distinctions in PCOS Induced by Letrozole Vs Dehydroepiandrosterone With High-fat Diet in Mouse Model

Polycystic ovarian syndrome (PCOS) is a complex health condition associated with metabolic disturbances and infertility. Recent data suggest that the prevalence of PCOS is increasing among women globally, although the etiology of these trends is undefined. Consequently, preclinical models that better reflect the biology of PCOS are urgently needed to facilitate research that can lead to the discovery of prevention strategies or improved management. The existing animal models have several limitations as they do not reflect all the PCOS features metabolically and/or phenotypically. Therefore, there is no clear consensus on the use of appropriate animal model and selection of the most appropriate PCOS-inducing agent. To that end, we have established a Swiss albino mouse model of PCOS based on 3 weeks of daily treatment with letrozole (50 μg/day; intraperitoneal) and dehydroepiandrosterone (DHEA, 6 mg/100 g body weight; subcutaneous) in 5-week-old female mice fed on normal or high-fat diet (HFD). Mice were regularly assessed for body weight, blood glucose, and estrous cycle. Three weeks after drug administration, mice were sacrificed and assessed for blood-based metabolic parameters as well as ovarian function. Our results indicate that DHEA combined with HFD produces changes mimicking those of clinical PCOS, including elevated serum testosterone and luteinizing hormone, dyslipidemia, poor ovarian microenvironment, and development of multiple ovarian cysts, recapitulating cardinal features of PCOS. In comparison, normal diet and/or letrozole produced fewer features of PCOS. The data from the experimental models presented here can improve our understanding of PCOS, a growing concern in women's health.

Electroacupuncture improves metabolic and ovarian function in a rat model of polycystic ovary syndrome by decreasing white adipose tissue, increasing brown adipose tissue, and modulating the gut microbiota

BACKGROUND

Polycystic ovary syndrome (PCOS) affects 8%-15% of reproductive-age women and is associated with reproductive disorders, abdominal obesity, hyperinsulinemia, insulin resistance, type 2 diabetes, and cardiovascular diseases. Acupuncture, as a traditional physical therapy method, could affect various metabolic disorders such as obesity, hyperplasia, gout, and cardiovascular and cerebrovascular diseases in clinical practice. Moreover, electroacupuncture (EA) has been shown to decrease body weight in rats with PCOS; however, the mechanism of weight loss and the relationship between adipose tissue and gut microbiota remain unclear.

OBJECTIVE

To explore the effect and mechanism of EA on white and brown adipose tissues and gut microbiota, and its follow-up effect on reproductive function, in a rat model of PCOS.

METHODS

Daily EA treatment was administered at ST29 and SP6 in a dihydrotestosterone (DHT)-induced PCOS-like rat model (PCOS + EA group). Effects of EA on in vivo and in vitro adipose volume and weight, organ weight coefficients, body weight, hormonal profiles, and estrous cyclicity were measured, and compared with untreated PCOS model rats (PCOS group) and healthy rats (control group). Microbial DNA was extracted from the fecal samples to analyze group abundance and diversity.

RESULTS

EA improved estrous cyclicity, decreased body weight, decreased visceral and subcutaneous fat content, and increased brown adipose tissue weight. EA also normalized serum DHT and progesterone levels and improved glucose tolerance. There were few significant differences in the composition or diversity of the gut microbiota between control, PCOS, and PCOS + EA groups, except for the relative abundances of Tenericutes at the phylum level and Prevotella_9 at the genus level, which were significantly different in the PCOS group before and after EA treatment. Both are important microflora, strongly related to body weight.

CONCLUSION

EA regulated the metabolic disorders and improved reproductive function in this PCOS-like rat model by adjusting visceral fat and brown fat, as well as intestinal flora.