Metformin Ameliorates Uterine Defects in a Rat Model of Polycystic Ovary Syndrome

Metformin administration during pregnancy tends to reduce the risk of gestational diabetes mellitus and improve pregnancy outcomes in previously infertile women with polycystic ovary syndrome who become pregnant

OBJECTIVE

Metformin reduces incidences of miscarriage and preterm delivery in polycystic ovary syndrome (PCOS) women, but its impact on gestational diabetes mellitus (GDM) is conflicting. Hence, this study set up selection criteria to include previously infertile women with PCOS but without pre-existing DM who became pregnant, aiming to minimize confounders and investigate the influence of metformin on GDM, miscarriage, and preterm delivery.

METHODS

This study included 195 previously infertile women with PCOS who became pregnant. They were divided into metformin (receiving metformin during pregnancy) and control (not receiving metformin) groups without intervention.

RESULTS

Metformin group tended to have a lower incidence of GDM versus control group (13.3% versus 23.3%, P = 0.070). A logistic regression model adjusted for all baseline characteristics (demographics, infertile duration, and diabetes mellitus-related features) showed that metformin was associated with a decreased probability of GDM (odds ratio (OR): 0.426, P = 0.037). Metformin group showed a similar incidence of miscarriage (6.7% versus 11.1%, P = 0.273), but decreased incidences of preterm delivery (not statistically significant) (6.7% versus 13.3%, P = 0.091) and miscarriage or preterm delivery (13.3% versus 24.4%, P = 0.046) versus control group. A logistic regression model adjusted for all the aforementioned features revealed that metformin was related to a lower risk of miscarriage or preterm delivery (OR: 0.417, P = 0.040). Fetal outcomes, including birth weight (P = 0.245) and the incidence of 5 min-Apgar score ≤ 7 (P = 0.702), were similar between groups.

CONCLUSION

Metformin administration during pregnancy may reduce GDM, miscarriage, and preterm delivery risks without adverse effects on fetal outcomes in previously infertile women with PCOS.

Metformin ameliorates endometrial thickness in a rat model of thin endometrium

Metformin, a well-established anti-diabetic drug, is also used in managing various other metabolic disorders including polycystic ovarian syndrome (PCOS). There are evidences to show that metformin improves endometrial functions in PCOS women. However, fewer studies have explored the direct effects of metformin on endometrium. Previous in vitro studies have shown that therapeutic serum concentrations of metformin enhance endometrial epithelial cell proliferation. The present study was undertaken to investigate in vivo effects of metformin on endometrial proliferation in a rat model of thin endometrium. Toward this, a rat model of thin endometrium was developed. Metformin (0.1% or 1% w/v) was administrated orally for 15 days in rats with thin endometrium. Oral metformin administration for three consecutive estrous cycles (15 days) in the thin endometrium rat model led to an increase in endometrial thickness compared to sham endometrium. Histological analysis showed a significant increase in the number of endometrial glands (P < 0.05), stromal cells (P < 0.01) and blood vessels (P < 0.01) in metformin-treated (n = 10 in each group) uterine horns compared to sham (saline-treated) uterine horns in rats. The expression of proliferating cell nuclear antigen and vascular epithelial growth factor was found to be upregulated on treatment with 1% metformin-treated group (n = 7). However, pregnancy outcomes in the rats treated with metformin remained unaltered despite the restoration of endometrial thickness. In conclusion, the study demonstrated that metformin ameliorates endometrial thickness in a rat model of thin endometrium by increasing endometrial proliferation and angiogenesis, without restoration of embryo implantation.

Uterine histopathology and steroid metabolism in a polycystic ovary syndrome rat model

The aim of this study was to investigate uterine lesions, uterine endocrine status and expression of genes involved in uterine differentiation in a rat model of polycystic ovary syndrome (PCOS). The possible involvement of the androgen receptor (AR) was also investigated. PCOS rats showed an increased incidence of uterine epithelial and glandular lesions and elevated serum testosterone level, which was not detected in uterine tissue. Uterine 17β-estradiol, estrone and progesterone were detected in 100%, 75% and 50% of the animals, respectively. This was associated with a decrease in Star and an increase in Hsd17b2, Srd5a1 and Cyp19a1, suggesting that uterine steroids are not synthesized de novo in PCOS and that alterations in these enzymes may explain the absence of testosterone and low progesterone. In addition, ESR2 decreased and AR increased, suggesting possible steroid receptor crosstalk. Genes associated with uterine differentiation, PTEN and WNT5a, also showed reduced expression. PCOS rats treated with flutamide, an AR antagonist, were similar to PCOS rats in terms of uterine lesions, serum steroid levels, ESR2, PTEN and WNT5a expression. However, testosterone, AR and aromatase levels were similar to control rats, with decreased expression of ESR1 and HOXA10, suggesting that these expressions are AR dependent. Our results suggest that the primary cause of the observed uterine lesions in the PCOS rat model is the altered endocrine status and consequently changes in genes related to uterine differentiation.

Research hotspots of polycystic ovary syndrome and hyperandrogenism from 2008 to 2022: bibliometric analysis

BACKGROUND

Polycystic Ovary Syndrome (PCOS) is the most frequent endocrine disorder in female adults, and hyperandrogenism (HA) is the typical endocrine feature of PCOS. This study aims to investigate the trends and hotspots in the study of PCOS and HA.

METHODS

Literature on Web of Science Core Collection (WoSCC) from 2008 to 2022 was retrieved, and bibliometric analysis was conducted using VOSviewer and CiteSpace software.

RESULTS

A total of 2,404 papers were published in 575 journals by 10,121 authors from 2,434 institutions in 86 countries. The number of publications in this field is generally on the rise yearly. The US, China and Italy contributed almost half of the publications. Monash University had the highest number of publications, while the University of Adelaide had the highest average citations and the Karolinska Institute had the strongest cooperation with other institutions. Lergo RS contributed the most to the field of PCOS and HA. The research on PCOS and HA mainly focused on complications, adipose tissue, inflammation, granulosa cells, gene and receptor expression.

CONCLUSION

Different countries, institutions, and authors should facilitate cooperation and exchanges. This study will be helpful for better understanding the frontiers and hotspots in the areas of PCOS and HA.

Insights on the NF-κB system in polycystic ovary syndrome, attractive therapeutic targets

The nuclear factor κappa B (NF-κB) signaling plays a well-known function in inflammation and regulates a wide variety of biological processes. Low-grade chronic inflammation is gradually considered to be closely related to the pathogenesis of Polycystic ovary syndrome (PCOS). In this review, we provide an overview on the involvement of NF-κB in the progression of PCOS particularly, such as hyperandrogenemia, insulin resistance, cardiovascular diseases, and endometrial dysfunction. From a clinical perspective, progressive recognition of NF-κB pathway provides opportunities for therapeutic interventions aimed at inhibiting pathway-specific mechanisms. With the accumulation of basic experimental and clinical data, NF-κB signaling pathway was recognized as a therapeutic target. Although there have been no specific small molecule NF-κB inhibitors in PCOS, a plethora of natural and synthetic compound have emerged for the pharmacologic intervention of the pathway. The traditional herbs developed for NF-κB pathway have become increasingly popular in recent years. Abundant evidence elucidated that NF-κB inhibitors can significantly improve the symptoms of PCOS. Herein, we summarized evidence relating to how NF-κB pathway is involved in the development and progression of PCOS. Furthermore, we present an in-depth overview of NF-κB inhibitors for therapy interventions of PCOS. Taken together, the NF-κB signaling may be a futuristic treatment strategy for PCOS.

Extensive therapeutic effects, underlying molecular mechanisms and disease treatment prediction of Metformin: a systematic review

Metformin (Met), a first-line management for type 2 diabetes mellitus, has been expansively employed and studied with results indicating its therapeutic potential extending beyond glycemic control. Beyond its established role, this therapeutic drug demonstrates a broad spectrum of action encompassing over 60 disorders, encompassing metabolic conditions, inflammatory disorders, carcinomas, cardiovascular diseases, and cerebrovascular pathologies. There is clear evidence of Met's action targeting specific nodes in the molecular pathways of these diseases and, intriguingly, interactions with the intestinal microbiota and epigenetic processes have been explored. Furthermore, novel Met derivatives with structural modifications tailored to diverse diseases have been synthesized and assessed. This manuscript proffers a comprehensive thematic review of the diseases amenable to Met treatment, elucidates their molecular mechanisms, and employs informatics technology to prospect future therapeutic applications of Met. These data and insights gleaned considerably contribute to enriching our understanding and appreciation of Met's far-reaching clinical potential and therapeutic applicability.

Promising drug candidates for the treatment of polycystic ovary syndrome (PCOS) as alternatives to the classical medication metformin

Polycystic ovary syndrome (PCOS) is a prevalent hormonal disorder that affects women of reproductive age. It is characterized by abnormal production of androgens, typically present in small quantities in females. This study aimed to investigate the therapeutic potential of Irosustat (STX64), STX140, and compound 1G as new drug candidates for the treatment of letrozole-induced PCOS in female Wistar rats. 36 rats were divided into six groups of equal size. PCOS was induced in all groups, except the normal control group, by administering letrozole orally (1 mg/kg/day for 35 days). The onset of abnormal estrous cycle was confirmed by examining daily vaginal smears under a microscope. Subsequently, each rat group was assigned to a different treatment regimen, including one control group, one letrozole group, one metformin group (500 mg/kg/day) as a reference drug, and the other groups received a different drug candidate orally for 30 days. After treatment, blood collection was performed for biochemical measurements and determination of oxidative stress markers. The rats were dissected to separate ovaries and uterus for morphological, histological, and western blotting studies. Treatment with the drug candidates improved the ovaries and uterus weight measurements compared to the untreated PCOS group. The three tested drug candidates demonstrated promising improvements in lipid profile, blood glucose level, testosterone, progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol levels. In addition, western blotting confirmed their promising effects on Akt, mTOR, and AMPK-α pathways. This study led to the discovery of three promising drug candidates for the management of PCOS as alternatives to metformin.

The ameliorating effects of Guizhi Fuling Wan combined with rosiglitazone in a rat ovarian model of polycystic ovary syndrome by the PI3K/AKT/NF-κB and Nrf2/HO-1 pathways

OBJECTIVE

GuizhiFulingWan (GFW) has been reported to be effective against polycystic ovary syndrome (PCOS) by possessing oxidative stress and inflammation which related to PI3K/AKT/NF-κB, Nrf2/HO-1 pathway. This study aims to probe the effects and mechanisms of GFW combined with rosiglitazone on PCOS via PI3K/AKT/NF-κB and Nrf2/HO-1 pathways.

METHODS

A rat PCOS model established by dehydroepiandrosterone (DHEA) injection. The experiment was allocated to control, DHEA, GFW, rosiglitazone, GFW + rosiglitazone groups. Treatment for 30 days, we monitored weight and ovarian weight of rats. Fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), lipid metabolism indexes, estrous cycle and sex hormone-, inflammation-, oxidative stress-related factors were examined. Hematoxylin&eosin staining assessed ovarian tissue pathological changes. Western blot determined PI3K/AKT/NF-κB, Nrf2/HO-1 pathways-related markers.

RESULTS

GFW and rosiglitazone treatment suppressed body weight and ovarian weight in PCOS rats. They also decreased FBG, FINS, HOMA-IR while inhibited total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) and enhanced high-density lipoprotein (HDL). They ameliorated estrous cycle, ovarian histological changes and follicular development. They restrained testosterone (T), luteinizing hormone (LH) and accelerated estradiol (E2), progesterone (P), follicle stimulating hormone (FSH). They inhibited glutathione peroxidase (GSH-Px), malondialdehyde (MDA), superoxide dismutase (SOD) in serum while increased GSH-Px, SOD and decrease MDA in ovarian tissues. They reduced C-reactive protein, interleukin-18 (IL-18), tumor necrosis factor-α (TNF-α), IL-6, IL-1β levels. GFW and rosiglitazone co-intervention regulated PI3K/AKT/NF-κB and Nrf2/HO-1 pathways in PCOS rats.

CONCLUSION

GFW alleviated ovarian dysfunction in PCOS rats, which may be related to the PI3K/AKT/NF-κB, Nrf2/HO-1 pathways.

Defective Uterine Spiral Artery Remodeling and Placental Senescence in a Pregnant Rat Model of Polycystic Ovary Syndrome

Pregnancy-related problems have been linked to impairments in maternal uterine spiral artery (SpA) remodeling. The mechanisms underlying this association are still unclear. It is also unclear whether hyperandrogenism and insulin resistance, the two common manifestations of polycystic ovary syndrome, affect uterine SpA remodeling. We verified previous work in which exposure to 5-dihydrotestosterone (DHT) and insulin (INS) in rats during pregnancy resulted in hyperandrogenism, insulin intolerance, and higher fetal mortality. Exposure to DHT and INS dysregulated the expression of angiogenesis-related genes in the uterus and placenta and also decreased expression of endothelial nitric oxide synthase and matrix metallopeptidases 2 and 9, increased fibrotic collagen deposits in the uterus, and reduced expression of marker genes for SpA-associated trophoblast giant cells. These changes were related to a greater proportion of unremodeled uterine SpAs and a smaller proportion of highly remodeled arteries in DHT + INS-exposed rats. Placentas from DHT + INS-exposed rats exhibited decreased basal and labyrinth zone regions, reduced maternal blood spaces, diminished labyrinth vascularity, and an imbalance in the abundance of vascular and smooth muscle proteins. Furthermore, placentas from DHT + INS-exposed rats showed expression of placental insufficiency markers and a significant increase in cell senescence-associated protein levels. Altogether, this work demonstrates that increased pregnancy complications in polycystic ovary syndrome may be mediated by problems with uterine SpA remodeling, placental functionality, and placental senescence.

Multi-omics study identifies that PICK1 deficiency causes male infertility by inhibiting vesicle trafficking in Sertoli cells

BACKGROUND

Infertility affects approximately 10-15% of reproductive-age men worldwide, and genetic causes play a role in one-third of cases. As a Bin-Amphiphysin-Rvs (BAR) domain protein, protein interacting with C-kinase 1 (PICK1) deficiency could lead to impairment of acrosome maturation. However, its effects on auxiliary germ cells such as Sertoli cells are unknown.

PURPOSE

The present work was aimed to use multi-omics analysis to research the effects of PICK1 deficiency on Sertoli cells and to identify effective biomarkers to distinguish fertile males from infertile males caused by PICK1 deficiency.

METHODS

Whole-exome sequencing (WES) was performed on 20 infertility patients with oligozoospermia to identify pathogenic PICK1 mutations. Multi-omics analysis of a PICK1 knockout (KO) mouse model was utilized to identify pathogenic mechanism. Animal and cell function experiments of Sertoli cell-specific PICK1 KO mouse were performed to verify the functional impairment of Sertoli cells.

RESULTS

Two loss-of-function deletion mutations c.358delA and c.364delA in PICK1 resulting in transcription loss of BAR functional domain were identified in infertility patients with a specific decrease in serum inhibin B, indicating functional impairment of Sertoli cells. Multi-omics analysis of PICK1 KO mouse illustrated that targeted genes of differentially expressed microRNAs and mRNAs are significantly enriched in the negative regulatory role in the vesicle trafficking pathway, while metabolomics analysis showed that the metabolism of amino acids, lipids, cofactors, vitamins, and endocrine factors changed. The phenotype of PICK1 KO mouse showed a reduction in testis volume, a decreased number of mature spermatozoa and impaired secretory function of Sertoli cells. In vitro experiments confirmed that the expression of growth factors secreted by Sertoli cells in PICK1 conditional KO mouse such as Bone morphogenetic protein 4 (BMP4) and Fibroblast growth factor 2 (FGF2) were decreased.

CONCLUSIONS

Our study attributed male infertility caused by PICK1 deficiency to impaired vesicle-related secretory function of Sertoli cells and identified a variety of significant candidate biomarkers for male infertility induced by PICK1 deficiency.

Chemical Characterization and Ameliorating Effect of Centratherum anthelminticum Extract against Polycystic Ovary Syndrome in Wistar Rats

Polycystic ovary syndrome (PCOS) in females is an endocrine pathological condition of reproductive age which is usually caused by insulin resistance, hyperlipidemia, and oxidative stress. This research was aimed at evaluating the therapeutic effect of the Centratherum anthelminticum seed extract (CA) against PCOS in rodents as it is traditionally used to treat diabetes, inflammation, and gynecological problems. The CA was chemically characterized by high-performance liquid chromatography-diode array detection (HPLC-DAD). For the induction of PCOS, a high-fat diet (HFD) was given to all female Wistar rats for nine weeks except the normal control group, which was given a normal chow diet. Estradiol valerate was given to all rats except normal control. After the induction of PCOS, oral metformin (300 mg/kg) was given to the standard group, while CA was orally administered to diseased rats at 250, 500, and 750 mg/kg/day for 28 days. HPLC-DAD analysis revealed that kaempferol-3-pcoumaroylglucoside was present in the highest amount (146.8 ± 1.8 mg/g) of the extract followed by ferulic acid and malvidin-3-(6-caffeoyl)-glucoside. The in vivo results revealed a marked reduction in cholesterol and triglyceride levels in CA treatment groups. A significant rise was observed in progesterone and follicle stimulating hormone with a decrease in luteinizing hormone in the treatment groups as compared to disease control, which indicated normalization of the estrus cycle. The decrease in insulin resistance was characterized by low serum insulin levels in treatment groups. Treatment with CA also reduced inflammatory markers, such as IL-6 and NF-κB in PCOS rats. NrF2 and oxidative stress markers such as catalase, superoxide dismutase, malondialdehyde, and reduced glutathione were also improved by CA in the ovary of diseased rats. Histopathological examination showed the different developmental stages of normal follicles in CA-treated diseased rats which were indicative of a normal fertile estrous cycle. Overall, the results confirmed the efficacy of CA against PCOS in treating estradiol-HFD-induced PCOS due to its antidiabetic, anti-inflammatory, antihyperlipidemic, and antioxidant properties.

Regulatory mechanisms of HMGB1 and its receptors in polycystic ovary syndrome-driven gravid uterine inflammation

High-mobility group box 1 (HMGB1) is critical for inflammatory homeostasis and successful pregnancy, and there is a strong association among elevated levels of HMGB1, polycystic ovary syndrome (PCOS), chronic inflammation and pregnancy loss. However, the mechanisms responsible for PCOS-driven regulation of uterine HMGB1 and its candidate receptors [toll-like receptor (TLR) 2 and 4] and inflammatory responses during pregnancy remain unclear. In this study, we found a gestational stage-dependent decrease in uterine HMGB1 and TLR4 protein abundance in rats during normal pregnancy. We demonstrated that increased expression of HMGB1, TLR2 and TLR4 proteins was associated with activation of inflammation-related signalling pathways in the gravid uterus exposed to 5α-dihydrotestosterone and insulin, mimicking the clinical features (hyperandrogenism and insulin resistance) of PCOS and this elevation was completely inhibited by treatment with the androgen receptor (AR) antagonist flutamide. Interestingly, acute exposure to lipopolysaccharide suppressed HMGB1, TLR4 and inflammation-related protein abundance but did not affect androgen levels or AR expression in the gravid uterus with viable fetuses. Furthermore, immunohistochemical analysis revealed that, in addition to being localized predominately in the nuclear compartment, HMGB1 immunoreactivity was also detected in the cytoplasm in the PCOS-like rat uterus, PCOS endometrium and pregnant rat uterus with haemorrhagic and resorbed fetuses, possibly via activation of nuclear factor κB signalling. These results suggest that both AR-dependent and AR-independent mechanisms contribute to the modulation of HMGB1/TLR2/TLR4-mediated uterine inflammation. We propose that the elevation of HMGB1 and its receptors and disruption of the pro-/anti-inflammatory balance in the gravid uterus may participate in the pathophysiology of PCOS-associated pregnancy loss.

The effects of melatonin and metformin on histological characteristics of the ovary and uterus in letrozole-induced polycystic ovarian syndrome mice: A stereological study

Background

Polycystic ovarian syndrome (PCOS) with anovulation, hyperandrogenism, ovarian and uterine histological changes, menstrual irregularities, etc. signs is an infertility type. It seems that melatonin and metformin can improve these abnormalities.

Objective

To evaluate the effects of melatonin and metformin on the ovary and uterus in PCOS-induced mice using stereological methods.

Materials and Methods

Seventy-two adult female BALB/c mice (8-wk-old, 20-30 gr) were randomly divided into control (distilled water, gavage), PCOS (90 µg/kg letrozole, gavage), PCOS+metformin (500 mg/kg, gavage), PCOS+melatonin (10 mg/kg, intraperitoneal injection), and PCOS+melatonin control (0.5% ethanol saline) groups (n = 12/each). Another PCOS group was kept for a month to ensure that PCOS features remained. Finally, a stereological evaluation of the uterus and ovary was carried out, and vaginal cytology and serum testosterone levels were assessed.

Results

PCOS mice treated with metformin and melatonin had lower testosterone levels, body weight, and more regular estrus cycles than the PCOS group (p ≤ 0.001). A significant decrease in conglomerate and daughter gland numbers, and primary, secondary, atretic, and cystic follicles numbers with a significant increase in primordial and Graafian follicles, and corpus luteum numbers (p ≤ 0.001) was seen in these treated mice. Also, endometrial vessels' volume and length significantly increased, but ovarian, endometrial, myometrial, stromal, and glands volume, and endometrial and myometrial thickness dramatically declined (p ≤ 0.001).

Conclusion

It appears that metformin and melatonin could restore the PCOS phenotype including estrus cycle irregularity, high testosterone level, and ovarian and uterine micromorphology to the control levels. However, the 2 treatments had similar effects on the examined parameters.

Metformin ameliorates polycystic ovary syndrome in a rat model by decreasing excessive autophagy in ovarian granulosa cells via the PI3K/AKT/mTOR pathway

Polycystic ovary syndrome (PCOS) is a common gynecological disease accompanied by a variety of clinical features, including anovulation, hyperandrogenism, and ovarian abnormalities, resulting in infertility. PCOS affects approximately 6%-15% of all reproductive-age women worldwide. Metformin, a popular drug used to treat PCOS in patients, has beneficial effects in reducing hyperandrogenism and inducing ovulation; however, the mechanisms by which metformin ameliorates PCOS are not clear. Hence, we aimed to explore the mechanisms of metformin in treating PCOS. In the present study, we first treated a letrozole-induced PCOS rat model with metformin, detected the pathological recovery of PCOS, and then assessed the effects of metformin on H₂O₂-induced autophagy in ovarian granulosa cells (GCs) by detecting the level of oxidative stress and the expression of autophagy-associated proteins and key proteins in the PI3K/AKT/mTOR pathway. We demonstrated that metformin ameliorated PCOS in a rat model by downregulating autophagy in GCs, and metformin decreased the levels of oxidative stress and autophagy in H₂O₂-induced GCs and affected the PI3K/AKT/mTOR signaling pathway. Taken together, our results indicate that metformin ameliorates PCOS in a rat model by decreasing excessive autophagy in GCs via the PI3K/AKT/mTOR pathway, and this study provides evidence for targeted reduction of excessive autophagy of ovarian granulosa cells and improvement of PCOS.

Effects of metformin on the uterus of d-galactose-induced aging mice: Histomorphometric, immunohistochemical localization (B-cell lymphoma 2, Bcl2-associated X protein, and active capase3), and oxidative stress study

d-galactose (DG)-induced rodent aging model has widely been used for the study of age-related dysfunctions of various organs, including gonads and uterus. Antidiabetic drug metformin has gained an attention as antiaging drug in model organism and human but its effect on uterus has not been studied in relation to induced aging. Therefore, we investigated the effect of metformin on uterus of DG-induced aging mice model. Mice were randomly divided into three groups, that is, control (CN), DG-induced aging model and aging model treated with metformin. Histomorphometric results showed significantly decreased number of uterine glands, endometrial thickness, and increased luminal epithelium height in aging model. Furthermore, metformin resumed the number of uterine glands, endometrial thickness, and luminal epithelium height up to CN group. Metformin has also significantly decreased the age-associated oxidative stress (malondialdehyde and lipid hydroperoxide). Superoxide dismutase was significantly decreased in both treated groups compared to the CN group. However, catalase and glutathione peroxidase enzymes were significantly increased by metformin compared to the aging model. Immunostaining of active caspase3 and BAX were intense in the endometrium of aging model compare to CN- and metformin-treated groups. Localization of B-cell lymphoma 2 (Bcl2) showed intense immunostaining in the uterus of CN- and metformin-treated groups, with mild immunostaining in aging model. Our observations suggested that metformin treatment might be helpful for management of age-associated uterine dysfunctions. Moreover, it may be concluded that metformin might ameliorate uterine dysfunctions by reducing oxidative stress, suppressing apoptosis, and increasing the survival/antiapoptotic protein Bcl2.

The role of MicroRNA networks in tissue-specific direct and indirect effects of metformin and its application

Metformin is a first-line oral antidiabetic agent that results in clear benefits in relation to glucose metabolism and diabetes-related complications. The specific regulatory details and mechanisms underlying these benefits are still unclear and require further investigation. There is recent mounting evidence that metformin has pleiotropic effects on the target tissue development in metabolic organs, including adipose tissue, the gastrointestinal tract and the liver. The mechanism of actions of metformin are divided into direct effects on target tissues and indirect effects via non-targeted tissues. MicroRNAs (miRNAs) are a class of endogenous, noncoding, negative gene regulators that have emerged as important regulators of a number of diseases, including type 2 diabetes mellitus (T2DM). Metformin is involved in many aspects of miRNA regulation, and metformin treatment in T2DM should be associated with other miRNA targets. A large number of miRNAs regulation by metformin in target tissues with either direct or indirect effects has gradually been revealed in the context of numerous diseases and has gradually received increasing attention. This paper thoroughly reviews the current knowledge about the role of miRNA networks in the tissue-specific direct and indirect effects of metformin. Furthermore, this knowledge provides a novel theoretical basis and suggests therapeutic targets for the clinical treatment of metformin and miRNA regulators in the prevention and treatment of cancer, cardiovascular disorders, diabetes and its complications.

Antioxidative Effects of Standardized Aronia melanocarpa Extract on Reproductive and Metabolic Disturbances in a Rat Model of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) represents the most common endocrinopathy among childbearing-age women, with oxidative stress (OS) underlying its etiopathogenesis. Metformin (MET) represents a frequently used agent in PCOS. However, weak results encourage alternative treatments. We aimed to investigate isolated and synergistic effects of Standardized Aronia melanocarpa extract (SEA) and MET for alleviating reproductive and metabolic PCOS abnormalities. PCOS induction was followed by 28-day treatment with MET, SAE, or MET + SEA. Bodyweight (BW), cyclicity, histological, and ultrasonographical ovarian analyses were performed. Hormonal, glycemic, and lipid profiles were accessed, as well as systemic and ovarian oxidative status; BW, cyclicity, ovarian histomorphology, ovarian volume, testosterone and progesterone levels, as well as LDL, triglycerides, and total cholesterol levels were aggravated after PCOS-induction and improved after MET, SEA, and MET + SEA treatment. MET + SEA had the greatest impact on glycoregulation. Alterations in OS parameters (TBARS, O₂⁻, H₂O₂, catalase, superoxide dismutase, and reduced glutathione) could be responsible for observed differences; (4) Conclusions: Our findings confirmed that SAE alone or along with MET was capable of ameliorating reproductive and metabolic disturbances in the PCOS rat model, with the restoration of OS parameters. SAE alone did not alter the protective effects of MET in PCOS.

Role of metformin in functional endometrial hyperplasia and polycystic ovary syndrome involves the regulation of MEG3/miR‑223/GLUT4 and SNHG20/miR‑4486/GLUT4 signaling

Metformin (MET) can effectively treat endometrial hyperplasia (EH), and the expression of glucose transporter type 4 insulin-responsive (GLUT4) is closely associated with the development of EH. The present study aimed to verify the effect of MET in functional EH and polycystic ovary syndrome (PCOS). H&E staining was performed to analyze the severity of EH, and immunohistochemistry was performed to evaluate the expression of GLUT4 in the endometrium of PCOS rats. Reverse transcription-quantitative PCR was used to calculate the expression of long non-coding (lnc)RNA-maternally expressed gene 3 (MEG3), lncRNA-small nucleolar RNA host gene 20 (SNHG20), GLUT4 mRNA, microRNA (miR)-223 and miR-4486. Sequence analysis and luciferase assays were performed to explore the regulatory relationship among certain lncRNAs, miRNAs and target genes. EH in PCOS rats was efficiently inhibited by MET administration. The increased expression of GLUT4 in PCOS rats was attenuated by MET treatment. Moreover, the expression levels of lncRNA-MEG3 and lncRNA-SNHG20 were significantly inhibited in the endometrium of PCOS rats. MET treatment also showed remarkable efficiency in restoring the expression of lncRNA-MEG3 and lncRNA-SNHG20. Meanwhile, the expression levels of miR-223 and miR-4486 were notably elevated in the endometrium of PCOS rats, while MET treatment reduced the expression of miR-223 and miR-4486 in PCOS rats. Furthermore, a luciferase assay confirmed the inhibitory relationship between miR-223 and lncRNA-MEG3/GLUT4 expression, as well as between miR-4486 and lncRNA-SNHG20/GLUT4 expression. GLUT4 knockdown restored the decreased viability of HCC-94 cells induced by overexpression of lncRNA-MEG3. To conclude, MET exhibited a therapeutic effect in the treatment of EH by modulating the lncRNA-MEG3/miR-223/GLUT4 and lncRNA-SNHG20/miR-4486/GLUT4 signaling pathways. This work provides mechanistic insight into the development of EH.

Modified Cangfu Daotan decoction ameliorates polycystic ovary syndrome with insulin resistance via NF-κB/LCN-2 signaling pathway in inflammatory microenvironment

This study explored the possible connection between the insulin resistance-targeting protein adipokine lipocalin-2 (LCN-2) and NF-κB signaling pathway in the inflammatory microenvironment in PCOS-IR model rats to determine the pharmacological mechanism of modified Cangfu Daotan decoction (MCDD) intervention for PCOS-IR. We used a high-fat diet (42 days) combined with letrozole (1 mg/kg/day, 42 days) to establish a PCOS-IR rat model. From the third week after modeling, the rats were given continuous administration of MCDD (high dose with 31.68 g/kg, medium dose with 15.84 g/kg, and low dose with 7.92 g/kg) for 28 days. Serum, ovarian tissue, liver, and adipose tissue were collected after the last gavage. Enzyme-linked immunosorbent assay, hematoxylin-eosin (HE) staining, Masson staining, qRT-PCR, and Western blot experiments were performed to detect various indicators. Our results showed that MCDD could reduce body weight and abdominal fat weight; restore normal estrous cycle and ovarian function; alleviate fatty liver; regulate HOMA-IR and OGTT index; reduce serum inflammatory factor levels, LCN-2 level, and gene expression; and regulate the insulin signal transduction and NF-κB pathways in PCOS-IR rats. Thus, MCDD may play a role in improving ovarian function in PCOS-IR rats by downregulating NF-κB/LCN-2 proteins and upregulating the gene expression of Insr/Irs-1/Glut4 in the insulin signaling pathway in the inflammatory environment.

Suppression of uterine and placental ferroptosis by N-acetylcysteine in a rat model of polycystic ovary syndrome

The mechanisms that link hyperandrogenism and insulin (INS) resistance (HAIR) to the increased miscarriage rate in women with polycystic ovary syndrome (PCOS) remain elusive. Previous studies demonstrate that increased uterine and placental ferroptosis is associated with oxidative stress-induced fetal loss in a pre-clinical PCOS-like rat model. Here, we investigated the efficacy and molecular mechanism of action of the antioxidant N-acetylcysteine (NAC) in reversing gravid uterine and placental ferroptosis in pregnant rats exposed to 5α-dihydrotestosterone (DHT) and INS. Molecular and histological analyses showed that NAC attenuated DHT and INS-induced uterine ferroptosis, including dose-dependent increases in anti-ferroptosis gene content. Changes in other molecular factors after NAC treatment were also observed in the placenta exposed to DHT and INS, such as increased glutathione peroxidase 4 protein level. Furthermore, increased apoptosis-inducing factor mitochondria-associated 2 mRNA expression was seen in the placenta but not in the uterus. Additionally, NAC was not sufficient to rescue DHT + INS-induced mitochondria-morphological abnormalities in the uterus, whereas the same treatment partially reversed such abnormalities in the placenta. Finally, we demonstrated that NAC selectively normalized uterine leukemia inhibitory factor, osteopontin/secreted phosphoprotein 1, progesterone receptor, homeobox A11 mRNA expression and placental estrogen-related receptor beta and trophoblast-specific protein alpha mRNA expression. Collectively, our data provide insight into how NAC exerts beneficial effects on differentially attenuating gravid uterine and placental ferroptosis in a PCOS-like rat model with fetal loss. These results indicate that exogenous administration of NAC represents a potential therapeutic strategy in the treatment of HAIR-induced uterine and placental dysfunction.

Metformin and exenatide upregulate hepatocyte nuclear factor-4α, sex hormone binding globulin levels and improve hepatic triglyceride deposition in polycystic ovary syndrome with insulin resistance rats

OBJECTIVE

To explore the efficacy and underlying mechanisms of metformin and exenatide in reversing reproductive and metabolic disturbances in letrozole combined with high-fat diet-induced polycystic ovary syndrome (PCOS) rats.

METHODS

Rats with PCOS and insulin resistance (IR) were induced by intra-gastric instillation of letrozole combined with a high-fat diet and verified by histological screening of vaginal exfoliated cells. After metformin and exenatide supplementation, body weight, chow intake and ovarian morphology were observed. Serum biochemical profiles were analyzed using ELISA, while the levels of key anabolism-related proteins, including sex hormone binding globulin (SHBG), hepatocyte nuclear factor-4α (HNF-4α), PI3K, and AKT, were determined using western blotting.

RESULTS

The estrus cycle and ovarian morphology of rats with PCOS and IR were significantly recovered following metformin and exenatide treatment, with decreased body weight and chow intake. Furthermore, PCOS-induced changes in metabolic disorders including IR and hepatic triglyceride (TG) deposition, and hyperandrogenemia were reversed by treatment with both drugs. Specifically, the levels of HNF-4α and SHBG in liver tissue of rats with PCOS and IR were upregulated significantly.

CONCLUSIONS

Both metformin and exenatide could recover the estrous cycle and ovarian morphology, reduce body weight and high-fat chow intake, and improve glycolipid metabolism disorders and hyperandrogenemia in PCOS with IR rat models. Interestingly, our findings also highlight the potential of both therapeutic agents for improving IR by regulating the liver PI3K/AKT pathway, reducing the deposition of hepatic TG, as well as upregulating the levels of SHBG and HNF-4α in PCOS with IR rat liver tissue.

Adverse Effects of Metformin From Diabetes to COVID-19, Cancer, Neurodegenerative Diseases, and Aging: Is VDAC1 a Common Target?

Metformin has been used for treating diabetes mellitus since the late 1950s. In addition to its antihyperglycemic activity, it was shown to be a potential drug candidate for treating a range of other diseases that include various cancers, cardiovascular diseases, diabetic kidney disease, neurodegenerative diseases, renal diseases, obesity, inflammation, COVID-19 in diabetic patients, and aging. In this review, we focus on the important aspects of mitochondrial dysfunction in energy metabolism and cell death with their gatekeeper VDAC1 (voltage-dependent anion channel 1) as a possible metformin target, and summarize metformin’s effects in several diseases and gut microbiota. We question how the same drug can act on diseases with opposite characteristics, such as increasing apoptotic cell death in cancer, while inhibiting it in neurodegenerative diseases. Interestingly, metformin’s adverse effects in many diseases all show VDAC1 involvement, suggesting that it is a common factor in metformin-affecting diseases. The findings that metformin has an opposite effect on various diseases are consistent with the fact that VDAC1 controls cell life and death, supporting the idea that it is a target for metformin.

Autophagy in ovary and polycystic ovary syndrome: role, dispute and future perspective

Polycystic ovary syndrome (PCOS) is a unification of endocrine and metabolic disorders and has become immensely prevalent among women of fertile age. The prime organ affected in PCOS is the ovary and its distressed functioning elicits disturbed reproductive outcomes. In the ovary, macroautophagy/autophagy performs a pivotal role in directing the chain of events starting from oocytes origin until its fertilization. Recent discoveries demonstrate a significant role of autophagy in the pathogenesis of PCOS. Defective autophagy in the follicular cells during different stages of follicles is observed in the PCOS ovary. Exploring different autophagy pathways provides a platform for predicting the possible cause of altered ovarian physiology in PCOS. In this review, we have emphasized autophagy's role in governing follicular development under normal circumstances and in PCOS, including significant abnormalities associated with PCOS such as anovulation, hyperandrogenemia, metabolic disturbances, and related abnormality. So far, few studies have linked autophagy and PCOS and propose its essential role in PCOS progression. However, detailed knowledge in this area is lacking. Here we have summarized the latest knowledge related to autophagy associated with PCOS. This review's main objective is to provide a background of autophagy in the ovary, its possible connection with PCOS and suggested a novel proposal for future studies to aid a better understanding of PCOS pathogenesis.Abbreviations: AE: androgen excess; AF: antral follicle; AKT/PKB: AKT serine/threonine kinase; AMH: anti-Mullerian hormone; AMPK: AMP-activated protein kinase; ATG: autophagy-related; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; BMP: bone morphogenetic protein; CASP3: caspase 3; CL: corpus luteum; CYP17A1/P450C17: cytochrome P450 family 17 subfamily A member 1; CYP19A1: cytochrome P450 family 19 subfamily A member 1; DHEA: dehydroepiandrosterone; EH: endometrial hyperplasia; FF: follicular fluid; FOXO: forkhead box O; FSH: follicle stimulating hormone; GC: granulosa cell; GDF: growth differentiation factor; HA: hyperandrogenemia; HMGB1: high mobility group box 1; IGF1: insulin like growth factor 1; INS: insulin; IR: insulin resistance; LHCGR/LHR: luteinizing hormone/choriogonadotropin receptor; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPK/ERK: mitogen-activated protein kinase; MAPK8/JNK: mitogen-activated protein kinase 8; MTOR: mechanistic target of rapamycin kinase; MTORC: mechanistic target of rapamycin complex; NAFLD: nonalcoholic fatty liver disease; NFKB: nuclear factor kappa B; OLR1/LOX-1: oxidized low density lipoprotein receptor 1; oxLDL: oxidized low-density lipoproteins; PA: palmitic acid; PCOS: polycystic ovary syndrome; PF: primary follicle; PGC: primordial germ cell; PI3K: phosphoinositide 3-kinase; PMF: primordial follicle; ROS: reactive oxygen species; RP: resting pool; SIRT1: sirtuin 1; SQSTM1/p62: sequestosome 1; T2DM: type 2 diabetes mellitus; TC: theca cell; TUG1: taurine up-regulated 1.

Alterations of endometrial epithelial-mesenchymal transition and MAPK signalling components in women with PCOS are partially modulated by metformin in vitro

Growing evidence suggests that epithelial-mesenchymal transition (EMT) and its regulator mitogen-activated protein kinase (MAPK) contribute to endometria-related reproductive disorders. However, the regulation of EMT and MAPK signalling components in the endometrium from polycystic ovary syndrome (PCOS) patients has not been systematically investigated and remains elusive. In humans, how metformin induces molecular alterations in the endometrial tissues under PCOS conditions is not completely clear. Here, we recruited 7 non-PCOS patients during the proliferative phase (nPCOS), 7 non-PCOS patients with endometrial hyperplasia (nPCOSEH), 14 PCOS patients during the proliferative phase (PCOS) and 3 PCOS patients with endometrial hyperplasia (PCOSEH). Our studies demonstrated that compared with nPCOS, PCOS patients showed decreased Claudin 1 and increased Vimentin and Slug proteins. Similar to increased Slug protein, nPCOSEH and PCOSEH patients showed increased N-cadherin protein. Western blot and immunostaining revealed increased epithelial phosphorylated Cytokeratin 8 (p-CK 8) expression and an increased p-CK 8:CK 8 ratio in PCOS, nPCOSEH and PCOSEH patients compared to nPCOS patients. Although nPCOSEH and PCOSEH patients showed increased p-ERK1/2 and/or p38 protein levels, the significant increase in p-ERK1/2 expression and p-ERK1/2:ERK1/2 ratio was only found in PCOS patients compared to nPCOS patients. A significant induction of the membrane ERβ immunostaining was observed in the epithelial cells of PCOS and PCOSEH patients compared to nPCOS and nPCOSEH patients. While in vitro treatment with metformin alone increased Snail and decreased Claudin 1, N-cadherin and α-SMA proteins, concomitant treatment with metformin and E2 increased the expression of CK 8 and Snail proteins and decreased the expression of Claudin 1, ZO-1, Slug and α-SMA proteins. Our findings suggest that the EMT contributes to the switch from a healthy state to a PCOS state in the endometrium, which might subsequently drive endometrial injury and dysfunction. We also provide evidence that metformin differentially modulates EMT protein expression in PCOS patients depending on oestrogenic stimulation.

The effects of metformin treatment on the ovaries and uterus of offspring

OBJECTIVE

The aim of this study is to investigate the effects of metformin treatment at different dosage levels on the ovaries and uteruses of rat offspring in the course of the intrauterine period.

METHODS

 Saline, metformin (100 mg/kg/day), and metformin (200 mg/kg/day) were administered via oral gavage between the 6th and 15th days of gestation to the 9 pregnant rats (n = 3/group). After birth, 5 female offspring were separated from each group and perfused on the 60th day of postnatal development. The cortex and medulla volumes of the ovaries, the thicknesses of epithelium and endometrium of the uteruses and the total oocyte number density were estimated. In addition, the estradiol levels in blood samples were measured by the ELISA method.

RESULTS

There were no statistically significant differences among the groups regarding the number of oocytes, the volumes of ovarian cortex, medulla, primary and secondary follicles (p > .05). In comparison with the control group, the volume of the tertiary follicle, the thickness of the uterus epithelium, and the estradiol level were significantly decreased in Metformin 200 group (p < .05).

CONCLUSIONS

The gestational exposure to high dose metformin may result in decreased estradiol production and subsequently decreased endometrial thickness of offspring rats.

Increased uterine androgen receptor protein abundance results in implantation and mitochondrial defects in pregnant rats with hyperandrogenism and insulin resistance

Abstract

In this study, we show that during normal rat pregnancy, there is a gestational stage-dependent decrease in androgen receptor (AR) abundance in the gravid uterus and that this is correlated with the differential expression of endometrial receptivity and decidualization genes during early and mid-gestation. In contrast, exposure to 5α-dihydrotestosterone (DHT) and insulin (INS) or DHT alone significantly increased AR protein levels in the uterus in association with the aberrant expression of endometrial receptivity and decidualization genes, as well as disrupted implantation. Next, we assessed the functional relevance of the androgen-AR axis in the uterus for reproductive outcomes by treating normal pregnant rats and pregnant rats exposed to DHT and INS with the anti-androgen flutamide. We found that AR blockage using flutamide largely attenuated the DHT and INS-induced maternal endocrine, metabolic, and fertility impairments in pregnant rats in association with suppressed induction of uterine AR protein abundance and androgen-regulated response protein and normalized expression of several endometrial receptivity and decidualization genes. Further, blockade of AR normalized the expression of the mitochondrial biogenesis marker Nrf1 and the mitochondrial functional proteins Complexes I and II, VDAC, and PHB1. However, flutamide treatment did not rescue the compromised mitochondrial structure resulting from co-exposure to DHT and INS. These results demonstrate that functional AR protein is an important factor for gravid uterine function. Impairments in the uterine androgen-AR axis are accompanied by decreased endometrial receptivity, decidualization, and mitochondrial dysfunction, which might contribute to abnormal implantation in pregnant PCOS patients with compromised pregnancy outcomes and subfertility.

Key messages

The proper regulation of uterine androgen receptor (AR) contributes to a normal pregnancy process, whereas the aberrant regulation of uterine AR might be linked to polycystic ovary syndrome (PCOS)-induced pregnancy-related complications.

In the current study, we found that during normal rat pregnancy there is a stage-dependent decrease in AR abundance in the gravid uterus and that this is correlated with the differential expression of the endometrial receptivity and decidualization genes Spp1, Prl, Igfbp1, and Hbegf.

Pregnant rats exposed to 5α-dihydrotestosterone (DHT) and insulin (INS) or to DHT alone show elevated uterine AR protein abundance and implantation failure related to the aberrant expression of genes involved in endometrial receptivity and decidualization in early to mid-gestation.

Treatment with the anti-androgen flutamide, starting from pre-implantation, effectively prevents DHT + INS-induced defects in endometrial receptivity and decidualization gene expression, restores uterine mitochondrial homeostasis, and increases the pregnancy rate and the numbers of viable fetuses.

This study adds to our understanding of the mechanisms underlying poor pregnancy outcomes in PCOS patients and the possible therapeutic use of anti-androgens, including flutamide, after spontaneous conception.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00109-021-02104-z.

Role of pomegranate extract in restoring endometrial androgen receptor expression, proliferation, and pinopodes in a rat model of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a multifactorial hormonal disorder accompanied by impairment of endometrial function and structure. Pomegranate is recognized for its role in normalizing the female sex hormones in PCOS with little known about its effect on the accompanying endometrial histological alterations.

AIM OF THE WORK

To assess the possible ameliorative role of pomegranate juice extract (PJE) on endometrial injury in a rat model of PCOS.

MATERIAL AND METHODS

Forty adult albino rats were equally divided into 4 groups; control, PJE-treated (400mg/kg/day for 3 weeks), letrozole-treated (PCOS) (1mg/kg/day for 3 weeks), and PJE & PCOS groups. Serum Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), testosterone, estradiol, and tissue malondialdehyde (MDA) were assayed. Uterine samples were processed for histological staining with hematoxylin & eosin and Masson's trichrome stains, Ki67 and androgen receptor immunohistochemical staining, and scanning electron microscopy.

RESULTS

PCOS group revealed a significant increase in serum FSH, LH, testosterone, estradiol, and tissue MDA. Uterine sections depicted various histological alterations in the endometrium with signs of inflammation. A significant increase in the endometrial collagen fiber content, as well as a significant upregulation in Ki67 and androgen receptor immunohistochemical expression were detected. Scanning electron microscopy showed a significant decrease in the mean number of pinopodes. Concomitant administration of PJE efficiently restored the studied biochemical, histological, and immunohistochemical parameters.

CONCLUSION

PJE ameliorated PCOS accompanying endometrial histological alterations through its antioxidant, anti-inflammatory, anti-fibrotic, anti-proliferative, and anti-androgenic effects most probably due to its polyphenols content.

C1QTNF6 participates in the pathogenesis of PCOS by affecting the inflammatory response of granulosa cells‡

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease. It has been reported that chronic low-grade inflammation might participate in its pathogenesis. C1q and TNF related 6 (C1QTNF6) is a newly identified adiponectin paralog associated with inflammation. The aim of the present study was to investigate the role of C1QTNF6 in the development of chronic inflammation in PCOS and the underlying molecular mechanism. After analyzing the expression of C1QTNF6 in the serum and granulosa cells (GCs) of PCOS patients and healthy controls, we verified the roles of C1QTNF6 in inflammation through dehydroepiandrosterone-induced PCOS mouse models and cell models of lipopolysaccharide (LPS)-induced inflammation. The results demonstrated that C1QTNF6 expression in the serum and GCs of patients with PCOS was significantly elevated compared with those of the controls, and similar results were observed in the serum and ovary of PCOS mouse models. In PCOS mice and C1QTNF6-overexpressing PCOS mice, serum levels of pro-inflammatory factors including C-reactive protein (CRP), interleukin 6 (IL6), and tumor necrosis factor-α (TNFα) were increased, while the opposite effects were observed when C1QTNF6 was down-regulated in PCOS mice. Furthermore, C1QTNF6 overexpression up-regulated the levels of TNFα, IL6, and CRP and activated the AKT/NF-κB pathway in LPS-treated KGN cells, whereas C1QTNF6 knockdown and BAY-117082 (an NF-κB inhibitor) treatment resulted in the opposite effects. Taken together, our results indicate that C1QTNF6 is involved in the pathogenesis of PCOS by affecting the inflammatory response via the AKT/NF-κB signaling pathway.

TLR4-Associated IRF-7 and NFκB Signaling Act as a Molecular Link Between Androgen and Metformin Activities and Cytokine Synthesis in the PCOS Endometrium

CONTEXT

Low-grade chronic inflammation is commonly seen in polycystic ovary syndrome (PCOS) patients with elevated levels of inflammatory cytokines in the endometrium.

OBJECTIVE

This work aimed to increase the limited understanding of the mechanisms underlying cytokine synthesis and increased endometrial inflammation in PCOS patients.

METHODS

Endometrial biopsy samples were collected from non-PCOS (n = 17) and PCOS (n = 22) patients either during the proliferative phase of the menstrual cycle or with hyperplasia. Endometrial explants were prepared from PCOS patients and underwent pharmacological manipulation in vitro. The expression and localization of toll-like receptor 2 (TLR2)/4, key elements of innate immune signal transduction and nuclear factor κB (NFκB) signaling pathways, and multiple cytokines were comprehensively evaluated by Western blotting, immunohistochemistry, and immunofluorescence in endometrial tissues.

RESULTS

We demonstrated the distribution of protein expression and localization associated with the significantly increased androgen receptor, TLR2, and TLR4-mediated activation of interferon regulatory factor-7 (IRF-7) and NFκB signaling, cytokine production, and endometrial inflammation in PCOS patients compared to non-PCOS patients with and without endometrial hyperplasia. In vitro experiments showed that 5-dihydrotestosterone (DHT) enhanced androgen receptor, TLR4, IRF-7, and p-NFκB p65 protein expression along with increased interferon α (IFNα) and IFNɣ abundance. The effects of DHT on IRF-7, p-NFκB p65, and IFN abundance were abolished by flutamide, an antiandrogen. Although 17β-estradiol (E2) decreased p-IRF-7 expression with little effect on TLR-mediated IRF7 and NFκB signaling or on cytokine protein levels, exposure to metformin alone or in combination with E2 suppressed interleukin-1 receptor-associated kinase 4 (IRAK4), p-IRF-7, IRF-7, IκB kinase α (IKKα), p-NFκB p65, IFNɣ, and tumor necrosis factor α protein expression.

CONCLUSION

Cytokine synthesis and increased endometrial inflammation in PCOS patients are coupled to androgen-induced TLR4/IRF-7/NFκB signaling, which is inhibited by metformin treatment.

Inflammation and reproductive function in women with polycystic ovary syndrome†

Polycystic ovary syndrome (PCOS) is one of the most frequent endocrinopathies, affecting 5-10% of women of reproductive age, and is characterized by the presence of ovarian cysts, oligo, or anovulation, and clinical or biochemical hyperandrogenism. Metabolic abnormalities such as hyperinsulinemia, insulin resistance, cardiovascular complications, dyslipidemia, and obesity are frequently present in PCOS women. Several key pathogenic pathways overlap between these metabolic abnormalities, notably chronic inflammation. The observation that this mechanism was shared led to the hypothesis that a chronic inflammatory state could contribute to the pathogenesis of PCOS. Moreover, while physiological inflammation is an essential feature of reproductive events such as ovulation, menstruation, implantation, and labor at term, the establishment of chronic inflammation may be a pivotal feature of the observed reproductive dysfunctions in PCOS women. Taken together, the present work aims to review the available evidence about inflammatory mediators and related mechanisms in women with PCOS, with an emphasis on reproductive function.

Therapeutic Potentials of Low-Dose Tacrolimus for Aberrant Endometrial Features in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a major anovulatory infertility affecting a great proportion of women of childbearing age and is associated with obesity, insulin resistance and chronic inflammation. Poor endometrial receptivity and recurrent implantation failure are major hurdles to the establishment of pregnancy in women with PCOS. The accumulating body of evidence obtained from experimental and clinical studies suggests a link between inherent adaptive and innate immune irregularities and aberrant endometrial features in PCOS. The use of conventional therapeutic interventions such as lifestyle modification, metformin and ovarian stimulation has achieved limited clinical success in restoring ovulation and endometrial receptivity in women with PCOS. Unlike other immunosuppressive drugs prescribed in the clinical management of autoimmune and inflammatory disorders that may have deleterious effects on fertility and fetal development, preclinical studies in mice and in women without PCOS but with repeated implantation failure revealed potential therapeutic benefits for the use of low-dose tacrolimus in treating female infertility. Improved systemic and ovarian immune functions, endometrial progesterone receptor and coreceptor expressions and uterine vascular adaptation to pregnancy were among features of enhanced progesterone-receptor sensitivity in the low-dose tacrolimus-treated mouse model of the disease. In this review, we have compiled available experimental and clinical data in literature on endometrial progesterone resistance and current therapeutic options, as well as mechanisms of actions and reported outcomes relevant to the potential therapeutic benefits for the use of low-dose tacrolimus in treating PCOS-associated female infertility.

Prenatal testosterone exposure induces insulin resistance, uterine oxidative stress and pro-inflammatory status in rats

Prenatal androgen excess is considered one of the main causes of the development of polycystic ovary syndrome. In this study, we investigated the effect of prenatal hyperandrogenization (PH) on the physiology of the adult uterine tissue using a murine model of fetal programming caused by androgen excess in adult female rats. Pregnant rats were hyperandrogenized with testosterone and female offspring were studied when adult. Our results showed that PH leads to hyperglycemia and hyperinsulinemia. Consequently, PH developed insulin resistance and a systemic inflammatory state reflected by increased C-reactive protein. In the uterine tissue, levels of PPAR gamma-an important metabolic sensor in the endometrium-were found to be impaired. Moreover, PH induced a pro-inflammatory and an unbalanced oxidative state in the uterus reflected by increased COX-2, lipid peroxidation, and NF-κB. In summary, our results revealed that PH leads to a compromised metabolic state likely consequence of fetal reprogramming.

Polycystic Ovary Syndrome and the Forgotten Uterus

Polycystic ovary syndrome (PCOS) is a common disorder that affects various facets of fertility. Although the ovarian and metabolic aspects of the disease is well studied, its role in uterine dysfunction is not well understood. Our objective was to review the features of endometrial and uterine aberrations in women with PCOS. A systematic literature search was performed in PubMed, Medline, and the Cochrane Library databases for papers published in English up to March 2020. The following key words were used for the search: polycystic ovary syndrome, poly cystic ovarian disease, polycystic ovaries, PCOS, PCOD, PCO, PCOM, oligoovulation, anovulation, oligomenorrhea, amenorrhea, hyperandrogenism and this was combined with terms; endometrium, infertility, uterus, progesterone resistance, endometrial hyperplasia, pregnancy outcomes, preterm delivery. In this review, we highlight various uterine pathologies that are associated with PCOS and explore its impact on fertility. We also discuss key uterine molecular pathways that are altered in PCOS that may be related to infertility, endometrial hyperplasia and cancer.

Endometrial function in women with polycystic ovary syndrome: a comprehensive review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. An endometrial component has been suggested to contribute to subfertility and poor reproductive outcomes in affected women.

OBJECTIVE AND RATIONALE

The aim of this review was to determine whether there is sufficient evidence to support that endometrial function is altered in women with PCOS, whether clinical features of PCOS affect the endometrium, and whether there are evidence-based interventions to improve endometrial dysfunction in PCOS women.

SEARCH METHODS

An extensive literature search was performed from 1970 up to July 2020 using PubMed and Web of Science without language restriction. The search included all titles and abstracts assessing a relationship between PCOS and endometrial function, the role played by clinical and biochemical/hormonal factors related to PCOS and endometrial function, and the potential interventions aimed to improve endometrial function in women with PCOS. All published papers were included if considered relevant. Studies having a specific topic/hypothesis regarding endometrial cancer/hyperplasia in women with PCOS were excluded from the analysis.

OUTCOMES

Experimental and clinical data suggest that the endometrium differs in women with PCOS when compared to healthy controls. Clinical characteristics related to the syndrome, alone and/or in combination, may contribute to dysregulation of endometrial expression of sex hormone receptors and co-receptors, increase endometrial insulin-resistance with impaired glucose transport and utilization, and result in chronic low-grade inflammation, immune dysfunction, altered uterine vascularity, abnormal endometrial gene expression and cellular abnormalities in women with PCOS. Among several interventions to improve endometrial function in women with PCOS, to date, only lifestyle modification, metformin and bariatric surgery have the highest scientific evidence for clinical benefit.

WIDER IMPLICATIONS

Endometrial dysfunction and abnormal trophoblast invasion and placentation in PCOS women can predispose to miscarriage and pregnancy complications. Thus, patients and their health care providers should advise about these risks. Although currently no intervention can be universally recommended to reverse endometrial dysfunction in PCOS women, lifestyle modifications and metformin may improve underlying endometrial dysfunction and pregnancy outcomes in obese and/or insulin resistant patients. Bariatric surgery has shown its efficacy in severely obese PCOS patients, but a careful evaluation of the benefit/risk ratio is warranted. Large scale randomized controlled clinical trials should address these possibilities.

Catechins from oolong tea improve uterine defects by inhibiting STAT3 signaling in polycystic ovary syndrome mice

Background

It is showed that inflammation is causative factor for PCOS, leading to a decline in ovarian fertility. Previous studies have reported that tea consumption can reduce the incidence of ovarian cancer. We speculate that catechins from oolong tea (Camellia sinensis (L.) O. Kuntze) may have a potential therapeutic effect on PCOS. This study aims to investigate the effects of oolong tea catechins on the uterus of polycystic ovary syndrome (PCOS) mice induced by insulin combined with human chorionic gonadotropin (hCG).

Methods

Sixty female mice were divided into 6 groups (n = 10): model, model + Metformin 200 mg/kg, model + catechins 25 mg/kg, model + catechins 50 mg/kg, and model + catechins 100 mg/kg. Another forty female mice were divided into 4 groups (n = 10): control, control + catechins 100 mg/kg, model, and model + catechins 100 mg/kg. Ovarian and uterine weight coefficients, sex hormone levels, glucose metabolism and insulin resistance, and ovarian and uterine pathology were examined. Changes in NF-κB-mediated inflammation, MMP2 and MMP9 expressions, and STAT3 signaling were evaluated in the uterus of mice.

Results

Catechins could effectively reduce the ovarian and uterine organ coefficients, reduce the levels of E2, FSH and LH in the blood and the ratio of LH/FSH, and improve glucose metabolism and insulin resistance in PCOS mice induced by insulin combined with hCG. In addition, catechins could significantly down-regulated the expression of p-NF-κB p65 in the uterus and the protein expressions of the pro-inflammatory factors (IL-1β, IL-6, and TNF-α). The expressions of mmp2 and mmp9 associated with matrix degradation in uterine tissue were also significantly down-regulated by catechins. Further, catechins significantly reduced the expression of p-STAT3 and increased the expression of p-IRS1 and p-PI3K in the uterus of PCOS mice.

Conclusion

Catechins from oolong tea can alleviate ovarian dysfunction and insulin resistance in PCOS mice by inhibiting uterine inflammation and matrix degradation via inhibiting p-STAT3 signaling.

Prenatally androgenized female rats develop uterine hyperplasia when adult

Prenatal hyperandrogenization (PH) is hypothesized as one of the main factors contributing to the development of polycystic ovary syndrome (PCOS). In this study, we aimed to investigate the impact of prenatal exposure to androgen excess on the uterus when animals reach their adulthood. We found that PH altered the morphology of the uteri that show a hyperplastic morphology with increased total uterine thickness as well as luminal epithelium thickness, with both enhanced and altered distribution of glands as compared with controls. Morphological alterations were associated with an unbalanced homeostasis as assessed by the expression of regulators of cell cycle progression and cell death dynamics. PH also causes disturbances in the cell cycle of the uterine tissue and dysregulates cell death and survival pathways leading to the development of uterine hyperplasia. These findings suggest that PH may have a deleterious effect on the uterus.

Baicalin ameliorates polycystic ovary syndrome through AMP-activated protein kinase

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder and regarded as the leading cause of anovulatory infertility. PCOS is characterized by reproductive dysfunction and metabolic disorders. Baicalin (BAL) is one of the most potent bioactive flavonoids isolated from the radix of Scutellaria baicalensis. In the present study, we investigated the potential effects of BAL on PCOS in dehydroepiandrosterone-treated rats. We found that BAL notably reduced the serum levels of free testosterone, total testosterone, follicle-stimulating hormone, luteinizing hormone, progesterone, and estradiol in PCOS rats. The increase of serum insulin level and HOMA-IR was markedly inhibited by BAL. Moreover, BAL decreased body weights, increased the number of rats with the regular estrous cycle, and ameliorated ovarian histological changes and follicular development in the DHEA-treated PCOS rats. The increase of pro-inflammatory cytokines (TNFα, IL-1β, and IL-18) and decrease of anti-inflammatory cytokine (IL-10) in PCOS rats were suppressed by BAL. BAL induced a significant decrease in the mRNA expression of steroidogenic enzymes, including 3β-HSD, CYP11A1, CYP19A1, StAR, in ovarian tissues in PCOS rats. Furthermore, BAL inhibited the decrease of AMPK protein level and phosphorylation, the decrease of Akt phosphorylation and the increase of 5α-reductase enzyme 1 expression in ovarian tissues in PCOS rats. The effects of BAL were inhibited by an inhibitor of AMPK, dorsomorphin. The upregulation of AMPK contributed to the beneficial effects of BAL. The results highlight the potential role of BAL for the intervention of PCOS.

Uterine glycolytic enzyme expression is affected by knockout of different estrogen receptor subtypes

The estrogen signaling pathway via nuclear estrogen receptors (ER) α and β is considered to be the master regulator of the cellular glucose metabolism in the uterus. While in vivo animal studies have demonstrated that 17β-estradiol (E2) treatment increases the expression levels and activities of several glycolytic enzymes in the uterus, the specific ER subtype-dependent regulation of key glycolytic enzymes in the uterus has not been experimentally verified. In this study, the localization of ERα and ERβ in human and mouse endometria were evaluated using immunohistology. Given that ERα and ERβ are not functionally equivalent, ERα, ERβ and ERαβ knockout (ERα^-/-, ERβ^-/- and ERαβ^-/-) mice were utilized to determine the expression pattern of glycolytic enzymes in the uterus. It was found that the level of ERα was higher than that of ERβ in the human and mouse endometrial epithelial and stromal cells, and both receptors were downregulated by E2 treatment in the mouse uterus. The expression of the hexokinase 1 and GAPDH was increased in ERα^-/- and ERβ^-/- mice compared with wild-type controls. Increased phosphofructokinase expression was observed in ERα^-/- and ERαβ^-/- mice, whereas increased pyruvate kinase isozyme M2 and pyruvate dehydrogenase expression was observed in ERβ^-/- and ERαβ^-/- mice. The findings indicated for the first time that while estrogen regulates ERα and ERβ expression in the uterus, ERα and ERβ selectively regulate uterine glycolytic enzyme expression during glycolysis. Additionally, the link between endometrial ER subtypes and glycolysis in women with polycystic ovary syndrome (PCOS) is discussed. The findings suggested that the E2-dependent ER-mediated regulation of glycolysis may be involved in the disturbance of the glucose metabolism in patients with PCOS with endometrial dysfunction.

Perturbed ovarian and uterine glucocorticoid receptor signaling accompanies the balanced regulation of mitochondrial function and NFκB-mediated inflammation under conditions of hyperandrogenism and insulin resistance

AIM

This study aimed to determine whether glucocorticoid receptor (GR) signaling, mitochondrial function, and local inflammation in the ovary and uterus are intrinsically different in rats with hyperandrogenism and insulin resistance compared to controls.

MAIN METHODS

Female Sprague Dawley rats were exposed to daily injections of human chorionic gonadotropin and/or insulin.

KEY FINDINGS

In both the ovary and the uterus, decreased expression of the two GR isoforms was concurrent with increased expression of Fkbp51 but not Fkbp52 mRNA in hCG + insulin-treated rats. However, these rats exhibited contrasting regulation of Hsd11b1 and Hsd11b2 mRNAs in the two tissues. Further, the expression of several oxidative phosphorylation-related proteins decreased in the ovary and uterus following hCG and insulin stimulation, in contrast to increased expression of many genes involved in mitochondrial function and homeostasis. Additionally, hCG + insulin-treated rats showed increased expression of ovarian and uterine NFκB signaling proteins and Tnfaip3 mRNA. The mRNA expression of Il1b, Il6, and Mmp2 was decreased in both tissues, while the mRNA expression of Tnfa, Ccl2, Ccl5, and Mmp3 was increased in the uterus. Ovaries and uteri from animals co-treated with hCG and insulin showed increased collagen deposition compared to controls.

SIGNIFICANCE

Our observations suggest that hyperandrogenism and insulin resistance disrupt ovarian and uterine GR activation and trigger compensatory or adaptive effects for mitochondrial homeostasis, allowing tissue-level maintenance of mitochondrial function in order to limit ovarian and uterine dysfunction. Our study also suggests that hyperandrogenism and insulin resistance activate NFκB signaling resulting in aberrant regulation of inflammation-related gene expression.

Hyperandrogenism and insulin resistance-induced fetal loss: evidence for placental mitochondrial abnormalities and elevated reactive oxygen species production in pregnant rats that mimic the clinical features of polycystic ovary syndrome

KEY POINTS

Women with polycystic ovary syndrome (PCOS) commonly suffer from miscarriage, but the underlying mechanisms remain unknown. Herein, pregnant rats chronically treated with 5α-dihydrotestosterone (DHT) and insulin exhibited hyperandrogenism and insulin resistance, as well as increased fetal loss, and these features are strikingly similar to those observed in pregnant PCOS patients. Fetal loss in our DHT+insulin-treated pregnant rats was associated with mitochondrial dysfunction, disturbed superoxide dismutase 1 and Keap1/Nrf2 antioxidant responses, over-production of reactive oxygen species (ROS) and impaired formation of the placenta. Chronic treatment of pregnant rats with DHT or insulin alone indicated that DHT triggered many of the molecular pathways leading to placental abnormalities and fetal loss, whereas insulin often exerted distinct effects on placental gene expression compared to co-treatment with DHT and insulin. Treatment of DHT+insulin-treated pregnant rats with the antioxidant N-acetylcysteine improved fetal survival but was deleterious in normal pregnant rats. Our results provide insight into the fetal loss associated with hyperandrogenism and insulin resistance in women and suggest that physiological levels of ROS are required for normal placental formation and fetal survival during pregnancy.

ABSTRACT

Women with polycystic ovary syndrome (PCOS) commonly suffer from miscarriage, but the underlying mechanism of PCOS-induced fetal loss during pregnancy remains obscure and specific therapies are lacking. We used pregnant rats treated with 5α-dihydrotestosterone (DHT) and insulin to investigate the impact of hyperandrogenism and insulin resistance on fetal survival and to determine the molecular link between PCOS conditions and placental dysfunction during pregnancy. Our study shows that pregnant rats chronically treated with a combination of DHT and insulin exhibited endocrine aberrations such as hyperandrogenism and insulin resistance that are strikingly similar to those in pregnant PCOS patients. Of pathophysiological significance, DHT+insulin-treated pregnant rats had greater fetal loss and subsequently decreased litter sizes compared to normal pregnant rats. This negative effect was accompanied by impaired trophoblast differentiation, increased glycogen accumulation, and decreased angiogenesis in the placenta. Mechanistically, we report that over-production of reactive oxygen species (ROS) in the placenta, mitochondrial dysfunction, and disturbed superoxide dismutase 1 (SOD1) and Keap1/Nrf2 antioxidant responses constitute important contributors to fetal loss in DHT+insulin-treated pregnant rats. Many of the molecular pathways leading to placental abnormalities and fetal loss in DHT+insulin treatment were also seen in pregnant rats treated with DHT alone, whereas pregnant rats treated with insulin alone often exerted distinct effects on placental gene expression compared to insulin treatment in combination with DHT. We also found that treatment with the antioxidant N-acetylcysteine (NAC) improved fetal survival in DHT+insulin-treated pregnant rats, an effect related to changes in Keap1/Nrf2 and nuclear factor-κB signalling. However, NAC administration resulted in fetal loss in normal pregnant rats, most likely due to PCOS-like endocrine abnormality induced by the treatment. Our results suggest that the deleterious effects of hyperandrogenism and insulin resistance on fetal survival are related to a constellation of mitochondria-ROS-SOD1/Nrf2 changes in the placenta. Our findings also suggest that physiological levels of ROS are required for normal placental formation and fetal survival during pregnancy.

Flutamide ameliorates uterine decidualization and angiogenesis in the mouse hyperandrogenemia model during mid-pregnancy

Background/Aim

Patients with polycystic ovary syndrome (PCOS), characterized by anovulation, hyperandrogenemia and polycystic ovaries, are still vulnerable to undergo recurrent pregnancy loss and premature labor even though the ovulatory process is pharmacologically recovered. However, its potential mechanism remains unknown. Thus, our aim was to investigate the effect and mechanism of hyperandrogenemia and flutamide (a non-steroidal anti-androgen) on the embryo implantation and pregnancy during mid-pregnancy.

Methods

We used a mouse model in which PCOS-like hyperandrogenemia was induced by subcutaneous injection of testosterone propionate. In this model, we observed the effect of hyperandrogenemia and flutamide on the decidualization, angiogenesis and uNK cells by methods of immunohistochemistry, quantitative PCR, western blotting and Dolichos biflorus agglutinin (DBA) lectin staining.

Results

Testosterone and flutamide treatment did not significantly influence the numbers of implanted embryo compared with the control group. However, different doses of testosterone significantly increased the ratio of resorbed /implanted embryo, decreased the level of prl8a2 mRNA and cyclin D3 protein, inhibited the uterine angiogenesis and reduced the numbers of uNK cells, but combined treatment with flutamide markedly decreased the resorbed embryos, increased expressions of prl8a2 mRNA and cyclin D3 protein and angiogenesis and numbers of uNK cells.

Conclusion

Flutamide treatment can efficiently ameliorate the hyperandrogenemia-induced the disorders in aspects of decidualization, angiogenesis and uNK cells, which further improve the poor endometrial receptivity in PCOS patients.

Hyperandrogenism and insulin resistance induce gravid uterine defects in association with mitochondrial dysfunction and aberrant reactive oxygen species production

Women with polycystic ovary syndrome (PCOS) are at increased risk of miscarriage, which often accompanies the hyperandrogenism and insulin resistance seen in these patients. However, neither the combinatorial interaction between these two PCOS-related etiological factors nor the mechanisms of their actions in the uterus during pregnancy are well understood. We hypothesized that hyperandrogensim and insulin resistance exert a causative role in miscarriage by inducing defects in uterine function that are accompanied by mitochondrial-mediated oxidative stress, inflammation, and perturbed gene expression. Here, we tested this hypothesis by studying the metabolic, endocrine, and uterine abnormalities in pregnant rats after exposure to daily injection of 5α-dihydrotestosterone (DHT; 1.66 mg·kg body wt^-1·day^-1) and/or insulin (6.0 IU/day) from gestational day 7.5 to 13.5. We showed that whereas DHT-exposed and insulin-exposed pregnant rats presented impaired insulin sensitivity, DHT + insulin-exposed pregnant rats exhibited hyperandrogenism and peripheral insulin resistance, which mirrors pregnant PCOS patients. Compared with controls, hyperandrogenism and insulin resistance in the dam were associated with alterations in uterine morphology and aberrant expression of genes responsible for decidualization (Prl8a2, Fxyd2, and Mt1g), placentation (Fcgr3 and Tpbpa), angiogenesis (Flt1, Angpt1, Angpt2, Ho1, Ccl2, Ccl5, Cxcl9, and Cxcl10) and insulin signaling (Akt, Gsk3, and Gluts). Moreover, we observed changes in uterine mitochondrial function and homeostasis (i.e., mitochondrial DNA copy number and the expression of genes responsible for mitochondrial fusion, fission, biogenesis, and mitophagy) and suppression of both oxidative and antioxidative defenses (i.e., reactive oxygen species, Nrf2 signaling, and interactive networks of antioxidative stress responses) in response to the hyperandrogenism and insulin resistance. These findings demonstrate that hyperandrogenism and insulin resistance induce mitochondria-mediated damage and a resulting imbalance between oxidative and antioxidative stress responses in the gravid uterus.

Differential Expression Patterns of Glycolytic Enzymes and Mitochondria-Dependent Apoptosis in PCOS Patients with Endometrial Hyperplasia, an Early Hallmark of Endometrial Cancer, In Vivo and the Impact of Metformin In Vitro

The underlying mechanisms of polycystic ovarian syndrome (PCOS)-induced endometrial dysfunction are not fully understood, and although accumulating evidence shows that the use of metformin has beneficial effects in PCOS patients, the precise regulatory mechanisms of metformin on endometrial function under PCOS conditions have only been partially explored. To address these clinical challenges, this study aimed to assess the protein expression patterns of glycolytic enzymes, estrogen receptor (ER), and androgen receptor (AR) along with differences in mitochondria-dependent apoptosis in PCOS patients with and without endometrial hyperplasia in vivo and to investigate the effects of metformin in PCOS patients with endometrial hyperplasia in vitro. Here, we showed that compared to non-PCOS patients and PCOS patients without hyperplasia, the endometria from PCOS patients with hyperplasia had a distinct protein expression pattern of glycolytic enzymes, including pyruvate kinase isozyme M2 isoform (PKM2) and pyruvate dehydrogenase (PDH), and mitochondrial transcription factor A (TFAM). In PCOS patients with endometrial hyperplasia, increased glandular epithelial cell secretion and infiltrated stromal cells in the glands were associated with decreased PDH immunoreactivity in the epithelial cells. Using endometrial tissues from PCOS patients with hyperplasia, we found that in response to metformin treatment in vitro, hexokinase 2 (HK2) expression was decreased, whereas phosphofructokinase (PFK), PKM2, and lactate dehydrogenase A (LDHA) expression was increased compared to controls. Although there was no change in PDH expression, metformin treatment increased the expression of TFAM and cleaved caspase-3. Moreover, our in vivo study showed that while endometrial ERβ expression was no different between non-PCOS and PCOS patients regardless of whether or not hyperplasia was present, ERα and AR protein expression was gradually increased in women with PCOS following the onset of endometrial hyperplasia. Our in vitro study showed that treatment with metformin inhibited ERα expression without affecting ERβ expression. Our findings suggest that decreased glycolysis and increased mitochondrial activity might contribute to the onset of ERα-dependent endometrial hyperplasia and that metformin might directly reverse impaired glycolysis and normalize mitochondrial function in PCOS patients with endometrial hyperplasia.

Shaoyao-Gancao Decoction alleviated hyperandrogenism in a letrozole-induced rat model of polycystic ovary syndrome by inhibition of NF-κB activation

Shaoyao-Gancao Decoction (SGD) has been widely used for the treatment of gynopathy. The present study aimed to evaluate the therapeutic effect and potential mechanism of SGD on hyperandrogenism in polycystic ovary syndrome (PCOS) rats. In the present work, SGD was orally administrated to the PCOS rats at the dose of 12.5, 25, and 50 g/kg/d for 14 consecutive days. UPLC–MS/MS was performed to identify the main chemical components of SGD. Body weight, ovarian weight, cystic dilating follicles, and serum levels of steroid hormones were tested to evaluate the therapeutic effect of SGD. In order to further clarify the underlying mechanism, we also measured mRNA and the protein levels of NF-κB, NF-κB p65, P-NF-κB p65, and IκB by RT-qPCR and Western blotting techniques. Our results showed that SGD treatment significantly alleviated hyperandrogenism in PCOS rats as evidenced by reduced serum levels of T and increased E₂ and FSH levels. In addition, SGD effectively reduced the phosphorylation of NF-κB p65 and increased the expression of IκB. Results of the present study demonstrated that SGD could ameliorate hyperandrogenism in PCOS rats, and the potential mechanism may relate to the NF-κB pathway.

Autophagy as an emerging target in cardiorenal metabolic disease: From pathophysiology to management

Although advances in medical technology and health care have improved the early diagnosis and management for cardiorenal metabolic disorders, the prevalence of obesity, insulin resistance, diabetes, hypertension, dyslipidemia, and kidney disease remains high. Findings from numerous population-based studies, clinical trials, and experimental evidence have consolidated a number of theories for the pathogenesis of cardiorenal metabolic anomalies including resistance to the metabolic action of insulin, abnormal glucose and lipid metabolism, oxidative and nitrosative stress, endoplasmic reticulum (ER) stress, apoptosis, mitochondrial damage, and inflammation. Accumulating evidence has recently suggested a pivotal role for proteotoxicity, the unfavorable effects of poor protein quality control, in the pathophysiology of metabolic dysregulation and related cardiovascular complications. The ubiquitin-proteasome system (UPS) and autophagy-lysosomal pathways, two major although distinct cellular clearance machineries, govern protein quality control by degradation and clearance of long-lived or damaged proteins and organelles. Ample evidence has depicted an important role for protein quality control, particularly autophagy, in the maintenance of metabolic homeostasis. To this end, autophagy offers promising targets for novel strategies to prevent and treat cardiorenal metabolic diseases. Targeting autophagy using pharmacological or natural agents exhibits exciting new strategies for the growing problem of cardiorenal metabolic disorders.

Impact of styrene maleic anhydride (SMA) based hydrogel on rat fallopian tube as contraceptive implant with selective antimicrobial property

Development of non-hormonal female contraception is a need to combat against increasing population growth. The presently available short term or long term female contraceptives and sterilization methods have their own restrictions and side effects. With this objective, herein, we describe an innovative insight about the use of hydrogel formulation consisting of Styrene Maleic Anhydride (SMA) dissolved in Dimethyl Sulfoxide (DMSO) as non-hormonal fallopian tube contraceptive implant. Firstly, in vitro behavior of SMA hydrogel was evaluated by in vitro swelling and rheological properties to comprehend the polymeric hydrogel property post implantation inside the fallopian tube. Simulated Uterine Fluid (SUF) was used to simulate female reproductive tract environment in this study. Mechanical strength of the hydrogel when subjected to dynamic environment post implantation in the fallopian tube was estimated by the G' values demonstrated. SMA hydrogel expressed selective antimicrobial activity against opportunistic pathogens (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) while having limited consequence over the growth of Lactobacillus spp. After confirmation of cytocompatibility against primary rat endometrial cell lines, the polymeric hydrogel was implanted inside the uterine horns of Sprague-Dawley rats. In vivo biocompatibility of the hydrogel was confirmed by histological and immunohistochemical evaluation of uterine tissue sections. Hematology, blood biochemistry and organ toxicity (kidney, liver, spleen, lungs and heart) also revealed biocompatibility of SMA hydrogel. The results of the current study indicated that the SMA copolymer dissolved in DMSO to form hydrogel has excellent biocompatibility for application as female contraceptive gel which can be implanted in the fallopian tube.

Endometrial progesterone receptor isoforms in women with polycystic ovary syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) affects approximately 4%-18% of all reproductive-aged women and is often accompanied by endometrial progesterone (P4) resistance. Endometrial cells from PCOS patients display increased progesterone receptor (PGR) expression; however, in vivo knockout studies and in vitro experiments indicate the two PGR isoforms are not functionally equivalent.

OBJECTIVE

We aimed to compare endometrial PGR isoform expression between non-PCOS and PCOS patients during the proliferative phase.

DESIGN

A case-control study. The expression of PGR isoforms (PGRA and PGRB), estrogen receptor alpha (ERα), and markers of cell proliferation was determined by qRT-PCR, Western blot, immunohistochemistry, and immunofluorescence assays.

PATIENT(S)

Patients were recruited and diagnosed with PCOS according to the Rotterdam criteria provided by the American Society for Reproductive Medicine and the European Society for Human Reproduction and Embryology. Endometrial biopsy samples were collected from non-PCOS patients with regular menstrual cycles or with hyperplasia (n = 11) and from PCOS patients with or without hyperplasia (n = 14).

RESULT(S)

Although the alteration of PGRB mRNA and protein expression was different, we found that PGRA mRNA and protein expression was higher in PCOS patients than non-PCOS patients. PGRA/B and PGRB were localized in both epithelial and stromal cells, with notable changes in the nuclei of epithelial and stromal cells. A similar expression pattern of ERα, vimentin and Ki-67, in association with an increased PGR expression, was observed in PCOS patients.

CONCLUSION(S)

These results demonstrated that elevated both PGR isoform expression depends on the presence of PCOS, and our data suggest that abnormal regulation of PGR isoforms is a pathological outcome of defective endometrium in PCOS patients.

Insulin Sensitizers Modulate GnRH Receptor Expression in PCOS Rats

BACKGROUND

Insulin sensitizers like metformin and pioglitazone are clinically used since last decades for the treatment of PCOS, but their efficacy and possible role in PCOS patients remains questionable. Also, the mechanism by which these insulin sensitizers show effect is not clear.

AIM OF THE STUDY

To evaluate the effect of metformin and pioglitazone on leutinizing hormone and follicle stimulating hormone receptor mRNA expression, hyperandrogenism and insulin resistance in high fat diet induced and letrozole induced PCOS in rats.

METHODS

Pre-pubertal female rats were divided into four groups: group I received normal pellet diet and group II, III and IV received high fat diet. After 105 d of dietary manipulation, metformin and pioglitazone treatment was given to group III and group IV animals respectively for 21 d. Similarly, adult female rats were divided into four groups: group I received 1% carboxymethyl cellulose (CMC) and group II, III, IV received letrozole for 21 d. After 21 d of letrozole administration, metformin and pioglitazone treatment was given to group III and group IV animals respectively for 21 d. Oral glucose tolerance test, lipid profile, fasting glucose, insulin, estrus cycle, hormonal profile, ovary weight, leutinizing hormone receptor and follicle stimulating hormone receptor mRNA expression was measured. Polycystic ovarian morphology was assessed through histopathological changes of ovary.

RESULTS AND CONCLUSION

Metformin and pioglitazone treatment improve both metabolic and reproductive parameters of PCOS including hyperinsulinemia and hyperandrogenism. LH receptor and FSH receptor mRNA expression were altered by pioglitazone and metformin treatment.