Acetate restores hypothalamic-adipose kisspeptin status in a rat model of PCOS by suppression of NLRP3 immunoreactivity

Multiple effects of kisspeptin on neuroendocrine, reproduction, and metabolism in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a highly prevalent and heterogeneous disease characterized by a combination of reproductive and endocrine abnormalities, often associated with metabolic and mental health disorders. The etiology and pathogenesis of PCOS remain unclear, but recent research has increasingly focused on the upstream mechanisms underlying its development. Among these, kisspeptin (KISS) signaling has emerged as a pivotal component in the regulation of the hypothalamic-pituitary-gonadal axis, with significant roles in reproductive function, energy regulation, and metabolism. Women with PCOS commonly exhibit disruptions in gonadotropin secretion, including elevated luteinizing hormone (LH) levels, imbalanced LH/follicle-stimulating hormone (FSH) ratios, and increased androgen levels, all of which are usually parallel with abnormal KISS signaling. Furthermore, alterations in the KISS/KISS1R system within the central and circulatory systems, as well as peripheral tissues, have been implicated in the development of PCOS. These changes affect multiple pathophysiological domains, including reproductive function, energy regulation, metabolic homeostasis, inflammatory response, and emotional disorders, and are further influenced by lifestyle and environmental factors. This review aims to comprehensively summarize the existing experimental and clinical evidence supporting these roles of KISS in PCOS, with the goal of establishing a foundation for future research and potential clinical applications.

Acetate abates adipose-ovarian endocrinometabolic disturbance in experimentally induced polycystic ovarian syndrome

BACKGROUND

Besides ovarian dysfunction and infertility, individuals with polycystic ovarian syndrome (PCOS) also present a number of systemic disturbances including functional derangements in the adipose tissue which possibly aggravates the endocrinometabolic abnormality in PCOS. Epigenetic changes have been implicated in metabolic-related disorders including PCOS. However, its pathogenic involvement in adipose-ovarian dysfunction is unclear. Therefore, the present research was designed to investigate the impact of epigenetic regulator, particularly short chain fatty acids (SCFAs) on adipose-ovarian dysfunction in PCOS rat model.

MATERIALS AND METHODS

Eight-weeks-old female Wistar rats were allotted into four groups of n = 5, namely control, sodium acetate (SACT), letrozole (LETZ), and LETZ + SACT. Letrozole (1 mg/kg; p.o.) was administered daily for 21 days to induce PCOS. Thereafter, the animals were treated daily with SACT (200 mg/kg; p.o.) for 6 weeks.

RESULTS

Letrozole-induced PCOS rats were presented with androgen excess, insulin resistance/hyperinsulinemia, ovarian cystic follicles, increased levels of anti-Mullerian hormone, leptin, with a corresponding decrease in 17-β estradiol, and adiponectin. In addition, the LETZ group also showed dyslipidemia, decreased levels of adipose/ovarian sirtuin-1, adipose triglyceride, increased lipase activity as well as ovarian triglyceride, with corresponding increase in adipose/ovarian lipid peroxidation, caspase-6, TGF-β1, inflammatory response (TNF-α, NF-κB and MIF) and decreased GSH. Adipose/ovarian mitofusin 2 depletion was observed in LETZ group and this was accompanied by elevated HDAC2. Nevertheless, administration of acetate reversed these perturbations.

CONCLUSION

Overall, the present results suggest that acetate ameliorates adipose-ovarian metabolic and endocrine disruptions that accompany PCOS, and these beneficial effects of acetate are associated with reduction of HDAC2 levels and elevation of mitofusin 2/sirtuin-1.

Acetate attenuates hypothalamic pyroptosis in experimentally induced polycystic ovarian syndrome

This study hypothesized that SCFA, acetate impacts positively on hypothalamic pyroptosis and its related abnormalities in experimentally induced PCOS rat model, possibly through NrF2/HIF1-α modulation. Eight-week-old female Wister rats were divided into groups (n = 5), namely control, PCOS, acetate and PCOS + acetate groups. Induction of PCOS was performed by administering 1 mg/kg body weight of letrozole for 21 days. After PCOS confirmation, the animals were treated with 200 mg/kg of acetate for 6 weeks. Rats with PCOS were characterized with insulin resistance, leptin resistance, increased plasma testosterone as well as degenerated ovarian follicles. There was also a significant increase in hypothalamic triglyceride level, triglyceride-glucose index, inflammatory biomarkers (SDF-1 and NF-kB) and caspase-6 as well as plasma LH and triglyceride. A decrease was observed in plasma adiponectin, GnRH, FSH, and hypothalamic GABA with severe inflammasome expression in PCOS rats. These were accompanied by decreased level of NrF2/HIF1-α, and the alterations were reversed when treated with acetate. Collectively, the present results suggest the therapeutic impact of acetate on hypothalamic pyroptosis and its related comorbidity in PCOS, a beneficial effect that is accompanied by modulation of NrF2/HIF1-α.

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.

Cardiac energy depletion in a rat model of polycystic ovarian syndrome is reversed by acetate and associated with inhibitory effect of HDAC2/mTOR

In addition to the clinical manifestation of polycystic ovarian syndrome (PCOS), life-threatening diseases, especially hypertension and cardiovascular disease (CVD) are emerging critical complications of PCOS. Changes in cardiac energy remains an independent risk factor of CVD. Histone deacetylase (HDAC) inhibitors, including acetate has received attention for its beneficial role in energy regulation. Herein we hypothesized that acetate improves cardiac energy homeostasis in experimentally induced PCOS. Female Wistar rats (8-week-old) were divided into groups. To induce PCOS, 1 mg/kg of letrozole was given for 21 days. After confirmation of PCOS, acetate (200 mg/kg) was administered for 6 weeks. Rats with PCOS showed multiple ovarian cysts with androgen excess and decreased SHBG. The rats also manifested impaired glucose tolerance/hyperinsulinemia and hypertriglyceridemia. Increased systemic oxidative stress (malondialdehyde)/inflammatory (NF-kB/SDF-1) markers and nitric oxide deficiency (NO/eNOS) were observed. Though, the body weight was increased without affecting the cardiac mass index of PCOS rats. Nevertheless, there was an increase in cardiac triglyceride and oxidative stress/inflammatory markers with consequent cardiac injury, revealed by decreased levels of SIRT-1/HIF-1α and increased levels of CTGF/TGFβ-1 and plasma troponin T. These led to cardiac ATP depletion with increased AMP and AMP/ATP ratio. These alterations were accompanied by elevated levels of mTOR and HDAC2, which were reversed when treated with acetate. The present results interestingly suggest that HDAC2 inhibition by acetate reversed cardiac energy depletion and attendant cardiomorbidities in experimental PCOS model. A beneficial effect that is accompanied by suppressed expression of mTOR.

Inhibition of NLRP3 inflammasome-A potential mechanistic therapeutic for treatment of polycystic ovary syndrome?

This review article explores the relationship between the NOD-like receptor protein 3 (NLRP3) inflammasome and the risk of developing polycystic ovary syndrome (PCOS). The NLRP3 inflammasome, a fundamental element of the innate immune system, plays a crucial role in the production of proinflammatory mediators and pyroptosis, a type inflammatory cell death. We conducted a thorough search on scientific databases to gather relevant information on this topic, utilizing relevant keywords. The reviewed studies indicated a correlation between PCOS and a higher incidence of granulosa cell (GC) death and the presence of ovarian tissue fibrosis. NLRP3 inflammasome stimulation and subsequent pyroptosis in GCs play a significant role in the pathophysiology of PCOS. Active NLRP3 inflammasome is involved in the production of inflammatory mediators like interleukin-1β (IL-1β) and IL-18, contributing to the development of PCOS, particularly in overweight patients. Therefore, inhibiting NLRP3 activation and pyroptosis could potentially offer novel therapeutic strategies for PCOS. Some limited studies have explored the use of agents with antioxidant and anti-inflammatory properties, as well as gene therapy approaches, to target the NLRP3 and pyroptosis signaling pathways. This study overview the understanding of the relationship between NLRP3 inflammasome activation, pyroptosis, and PCOS. It highlights the potential of targeting the NLRP3 inflammasome as an approach for treating PCOS. Nonetheless, further research and clinical trials are imperative to validate these results and explore the effectiveness of NLRP3 inflammasome inhibition in the management of PCOS.

Modulation of GABA by sodium butyrate ameliorates hypothalamic inflammation in experimental model of PCOS

Polycystic ovarian syndrome (PCOS) is a known endocrine disorder that has affected many women of childbearing age, and is accompanied by various neurodegenerative conditions. Hence, this study investigates the impact of butyrate in reversing hypothalamic-related disorder, possibly through γ aminobutyric acid (GABA) in a rat model of PCOS. Eight-week-old female Wistar rats were allotted into four groups (n = 5), which include control, butyrate, letrozole, and letrozole + butyrate groups. PCOS was induced by administering 1 mg/kg of letrozole (oral gavage) for 21 days. After confirmation of PCOS, 200 mg/kg of butyrate (oral gavage) was administered for 6 weeks. Rats with PCOS were characterized by elevated levels of plasma insulin and testosterone. Increases in plasma and hypothalamic triglyceride levels, inflammatory biomarker (SDF-1), apoptotic marker (caspase-6), and decreased plasma GnRH were observed. Additionally, a decrease in hypothalamic GABA was revealed. Nevertheless, the administration of butyrate attenuated these alterations. The present study suggests that butyrate ameliorates hypothalamic inflammation in an experimental model of PCOS, a beneficial effect that is accompanied by enhanced GABA production.

Berberine interacts with gut microbiota and its potential therapy for polycystic ovary syndrome

Berberine (BBR) is an isoquinoline alkaloid extracted from Chinese medicinal plants showing a tight correlation with gut microbiota. Polycystic ovary syndrome (PCOS) is a prevalent reproductive and endocrine disorder syndrome among women of childbearing age. Dysbiosis, the imbalance of intestinal microorganisms, is a potential factor that takes part in the pathogenesis of PCOS. Recent evidence indicates that berberine offers promise for treating PCOS. Here, we review the recent research on the interaction between berberine and intestinal microorganisms, including the changes in the structure of gut bacteria, the intestinal metabolites after BBR treatment, and the effect of gut microbiota on the bioavailability of BBR. We also discuss the therapeutic effect of BBR on PCOS in terms of gut microbiota and its potential mechanisms.

Signaling pathways and targeted therapeutic strategies for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among women of reproductive age. Although promising strides have been made in the field of PCOS over the past decades, the distinct etiologies of this syndrome are not fully elucidated. Prenatal factors, genetic variation, epigenetic mechanisms, unhealthy lifestyles, and environmental toxins all contribute to the development of this intricate and highly heterogeneous metabolic, endocrine, reproductive, and psychological disorder. Moreover, interactions between androgen excess, insulin resistance, disruption to the hypothalamic-pituitary-ovary (HPO) axis, and obesity only make for a more complex picture. In this review, we investigate and summarize the related molecular mechanisms underlying PCOS pathogenesis from the perspective of the level of signaling pathways, including PI3K/Akt, TGF-β/Smads, Wnt/β-catenin, and Hippo/YAP. Additionally, this review provides an overview of prospective therapies, such as exosome therapy, gene therapy, and drugs based on traditional Chinese medicine (TCM) and natural compounds. By targeting these aberrant pathways, these interventions primarily alleviate inflammation, insulin resistance, androgen excess, and ovarian fibrosis, which are typical symptoms of PCOS. Overall, we hope that this paper will pave the way for better understanding and management of PCOS in the future.

The Role of NLRP3 Inflammasome in Obesity and PCOS-A Systematic Review and Meta-Analysis

Inflammasomes have recently been implicated in the pathogenesis of several chronic inflammatory disorders, such as diabetes and obesity. The aim of this meta-analysis was to investigate the possible role of the NLRP3 inflammasome in obesity and polycystic ovarian syndrome (PCOS). A comprehensive search of electronic databases was conducted to identify studies investigating NLRP3 its related components (Caspase 1, ASC and IL-1β) in adipose tissue and/or blood from obese individuals compared to non-obese controls. Another search was conducted for studies investigating NLRP3 in PCOS women and animal models. The ssearched databases included Medline, EMBASE, Cochrane Library, PubMed, Clinicaltrials.gov, the EU Clinical Trials Register and the WHO International Clinical Trials Register. The quality and risk of bias for the included articles were assessed using the modified Newcastle-Ottawa scale. Data were extracted and pooled using RevMan software for the calculation of the standardized mean difference (SMD) and 95% confidence interval (CI). Twelve eligible studies were included in the obesity systematic review and nine in the PCOS review. Of the obesity studies, nine (n = 270) were included in the meta-analysis, which showed a significantly higher adipose tissue NLRP3 gene expression in obese (n = 186) versus non-obese (n = 84) participants (SMD 1.07; 95% CI, 0.27, 1.87). Pooled analysis of adipose tissue IL-1β data from four studies showed significantly higher IL-1β gene expression levels in adipose tissue from 88 obese participants versus 39 non-obese controls (SMD 0.56; 95% CI, 0.13, 0.99). Meta-analysis of adipose tissue ASC data from four studies showed a significantly higher level in obese (n = 109) versus non-obese (n = 42) individuals (SMD 0.91, 95% CI, 0.30, 1.52). Of the nine PCOS articles, three were human (n = 185) and six were animal studies utilizing PCOS rat/mouse models. All studies apart from one article consistently showed upregulated NLRP3 and its components in PCOS women and animal models. In conclusion, obesity and PCOS seem to be associated with upregulated expression of NLRP3 inflammasome components. Further research is required to validate these findings and to elucidate the role of NLRP3 in obesity and PCOS.