Expression of the CD11c gene in subcutaneous adipose tissue is associated with cytokine level and insulin resistance in women with polycystic ovary syndrome

The role of macrophages in polycystic ovarian syndrome and its typical pathological features: A narrative review

Polycystic ovarian syndrome (PCOS) is the most common endocrine and metabolic disorder in women of childbearing age, with ovulatory dysfunction, hyperandrogenism, and polycystic ovarian morphology (PCOM) as the clinical features. Androgen excess, insulin resistance, obesity, adipose tissue dysfunction, ovulatory dysfunction, and gut microbiota dysbiosis are the main pathological features and pathogenesis of PCOS and are related to systemic chronic low-grade inflammation and chronic ovarian tissue inflammation in PCOS. With the advances in immune-endocrine interaction studies, research on the role of immune cells in the occurrence and development of PCOS is gradually increasing. As the core of innate immunity, macrophages play an indispensable role in systemic inflammatory response. Meanwhile, they are involved in maintaining the stability and function of the ovary as the most abundant immune cells in ovarian tissue. Studies in humans and mice have found that the polarization of macrophages into M1 type plays multiple roles in the pathogenesis of PCOS. This review describes the distribution characteristics of macrophage subpopulations in patients and animal models with PCOS, discusses the role of macrophage-related metabolic inflammation in PCOS, and summarizes the relationship between macrophages and PCOS-related pathological features and its possible mechanisms, to further understand the pathogenesis of PCOS and reveal the role of macrophages in it. In addition, research on immune-endocrine interactions can also provide direction for finding new therapeutic targets for PCOS.

The Role of Peroxisome Proliferator-Activated Receptors in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) constitutes the most common endocrine disorder in women of reproductive age. Patients usually suffer from severe menstrual irregularities, skin conditions, and insulin resistance-associated health conditions. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptor proteins that regulate gene expression. In order to investigate the role of PPARs in the pathophysiology of PCOS, we conducted a literature review using the MEDLINE and LIVIVO databases and were able to identify 74 relevant studies published between 2003 and 2023. Different study groups reached contradictory conclusions in terms of PPAR expression in PCOS. Interestingly, numerous natural agents were found to represent a novel, potent anti-PCOS treatment alternatives. In conclusion, PPARs seem to play a significant role in PCOS.

A network pharmacology study of mechanism and efficacy of Jiawei Huanglian-Wendan decoction in polycystic ovary syndrome with insulin resistance

Polycystic ovary syndrome (PCOS) is a common reproductive metabolic disorder, normally accompanied by insulin resistance (IR). The specific pathogenesis of this disease remains unclear. To identify the underlying pathogenesis of PCOS with IR and explore the potential efficacy and mechanism of Jiawei Huanglian-Wendan decoction (JHWD) by a network pharmacology approach. The effective components and the potential drug and disease-related targets are retrieved. Drug-disease overlapped targets are being obtained by Venny analysis. The construction of protein-protein interaction network relied on Search Tool for the Retrieval of Interacting Genes/Proteins database (STRING), after uploading drug-disease overlapped targets. The drug-component-target-disease interaction network map was displayed , after importing their data into Cytoscape 3.7.2 software. Bioinformatics analyses are being performed by Metascape and Kyoto Encyclopedia of Genes and Genomes databases, respectively. Further, molecular docking analysis was carried out using AutoDock software. Finally, the influence of JHWD is verified by means of traditional Chinese medicine syndrome score, the rate of resumption of normal menstrual cycles and regular ovulation, the blood lipid levels, the blood glucose and insulin levels, and the inflammatory cytokines in PCOS with IR patients. Four primary interaction networks of JHWD are constructed. The enrichment analysis of PCOS-IR-related targets demonstrated that the top enriched pathways in the development of PCOS with IR are pathways in cancer, metabolic, phosphoinositide-3-kinase-protein kinase B signaling, lipid and atherosclerosis, and mitogen-activated protein kinase signaling pathways. Molecular docking analysis revealed strong binding interactions of the key targets with the active components. Further confirmations showed that the active components of JHWD exhibited significant clinical efficacy in improving the clinical syndromes, menstrual cyclicity and ovulatory function, and significantly reducing the blood lipid levels, blood glucose and insulin levels, and inflammatory cytokines in PCOS with IR patients. The combination of the network pharmacological analysis and clinical validation stated that the active compounds in JHWD could regulate glycolipid metabolism, reduce IR, and exert anti-inflammatory effects in the treatment of PCOS with IR, promoting Chinese classical formulations.

Selenium can regulate the differentiation and immune function of human dendritic cells

Selenium is an essential trace element that can regulate the function of immnue cells via selenoproteins. However, the effects of selenium on human dendritic cell (DCs) remain unclear. Thus, selenoprotein levels in monocytes, immature DCs (imDCs) and mature DCs (mDCs) treated with or without Na₂SeO₃ were evaluated using RT-PCR, and then the immune function of imDCs and mDCs was detected by flow cytometry, cell counting and the CCK8 assay. In addition, the effects of Se on cytokine and surface marker expression were investigated by RT-PCR. The results revealed different expression levels of selenoprotein in monocytes, imDCs and mDCs, and selenoproeins could be regulated by Se. Moreover, it was indicated that anti-phagocytic activity was improved by 0.1 µM Se, whereas it was suppressed by 0.2 µM Se in imDCs; The migration of imDCs and mDCs was improved by 0.1 µM Se, whereas their migration was inhibited by treatment with 0.05 or 0.2 µM Se; The mixed lymphocyte reaction of mDCs was improved by 0.1 µM Se, and it was inhibited by 0.05 and 0.2 µM Se. In addition, 0.1 µM Se improved the immune function of DCs through the regulation of CD80, CD86, IL12-p35 and IL12-p40. Wheres 0.05 and 0.2 µM Se impaired immune function of DCs by up-regulation of interleukin (IL-10) in imDCs and down-regulation of CD80, CD86, IL12-p35 and IL12-p40 in mDCs. In conclusion, 0.1 µM Se might improve the immune function of human DCs through selenoproteins.

Relation between Inflammation, Oxidative Stress, and Macronutrient Intakes in Normal and Excessive Body Weight Adolescent Girls with Clinical Features of Polycystic Ovary Syndrome

The impact of diet on inflammation and oxidative stress (OS) in girls with polycystic ovary syndrome (PCOS) is unknown. Therefore, our study aimed to investigate, in PCOS girls, whether certain macronutrient intakes can be associated with these disturbances. For this purpose, 59 PCOS participants (aged 14-18 years) were recruited to this study and divided into two subgroups: overweight/obese-Ov/Ob group (n = 22) and normal weight-N group (n = 37). Nutrition was assessed using a 3-day food record. The studied markers were total antioxidant capacity (TAC), malondialdehyde (MDA), C-reactive protein (CRP), tumor necrosis factor α (TNF-α), and interleukins 1 and 6 (IL-1 and IL-6). We found plant protein intake inversely correlated with IL-6 (p = 0.007; r = -0.557), TNF-α (p = 0.006; r = -0.564), MDA (p = 0.01; r = -0.539) in the Ov/Ob group and with TAC (p = 0.021; r = -0.38) in the N group. Inverse correlations in the Ov/Ob group were observed between protein intake and IL-6 (p = 0.031; r = -0.461), TNF- α (p = 0.043; r = -0.435); carbohydrates and IL-6 (p = 0.037; r = -0.448), MDA (p = 0.045; r = -0.431); fiber and IL-6 (p = 0.025; r = -0.475). A positive relationship between cholesterol intake and CRP concentration (p = 0.038; r = 0.342) was also found in the N group. These findings revealed that inflammation and OS are increased in Ov/Ob girls with decreased plant protein intake and low carbohydrates in the diet. Moreover, inflammation may be increased by cholesterol intake in slim PCOS girls. On the other hand, decreased intake of fiber and total protein intake increased inflammation. ClinicalTrials.gov Identifier: NCT04738409.

Activation of Systemic Inflammation and Oxidative Stress in Adolescent Girls with Polycystic Ovary Syndrome in Combination with Metabolic Disorders and Excessive Body Weight

Relevance: Mitochondrial dysfunction and systemic inflammation are believed to play pivotal role in the pathogenesis of polycystic ovary syndrome (PCOS) and related complications of metabolic disorders in adult patients. Though such researches are limited or almost absent in adolescents. The aim of the study is to evaluate the impact of mitochondrial dysfunction and systemic inflammation on PCOS pathogenesis during adolescence with regard to body mass index and insulin resistance. Design: a case-control study. Methods: The study included 95 adolescent girls (15 to 17 years old inclusive) diagnosed with PCOS based on the Rotterdam criteria. The control group consisted of 30 healthy girls of the same age with a regular menstrual cycle. All participants were subjected to a full clinical and instrumental examination, as well as an assessment of the levels of leptin, C-reactive protein (CRP), and malondialdehyde (MDA) as oxidative stress marker. Serum levels of IL-6, IL-10, IL-18, TNF-α, and plasma concentrations of macrophage migration inhibitory factor (MIF), sFas, and sFasL were determined. Patients with PCOS were divided into groups according to the presence of metabolic disorders (MD) (impaired glucose tolerance and/or over insulin resistance) and normal weight or excessive weight (NW or OW). Results: Patients with PCOS of NW in the absence of metabolic disorders (MD−/NW) had a lower concentration of MDA and a higher level of IL-10 compared to healthy girls (p < 0.05). The group (MD−/NW) was characterized with lower levels of CRP, leptin, MDA, and higher levels of sFasL, when compared to OW patients with PCOS in the absence of metabolic disorders (MD−/OW) (p < 0.05). Overweight adolescent girls with PCOS and metabolic disorders (MD+/OW) showed higher CRP, leptin, and a two-fold increase in IL-6 and IL-18 concentrations compared to the control group of healthy girls (p < 0.05 for all parameters). The group (MD+/OW) was also characterized with higher levels of CRP, leptin, MDA, IL-18, MIF (p < 0.05), when compared to overweight patients with PCOS in the absence of metabolic disorders (MD−/NW). In comparison with the MD−/OW group, the obese insulin resistant girls with PCOS (MD+/OW) had a highera level of IL-18 (p < 0.05). Moreover, the MD+/OW girls demonstrated a significant increase in CRP, MDA and IL-18 levels when compared to the MD+/NW group (p < 0.05). OW girls with PCOS without MD (MD−/OW) had lower concentrations of sFasL compared to healthy girls (p < 0.05), and higher levels of MDA compared to MD+/NW (p < 0.05). Adolescent girls of NW with PCOS and with MD (MD+/NW) had lower levels of MDA compared to the control group of healthy girls (p < 0.05). These data are confirmed by a correlation analysis and two-factor ANOVA test. Conclusions: Lean girls with PCOS demonstrate the protective mechanism of decrease in oxidative stress mediated by the activation of antioxidant defense, reduction of lipid peroxidation and systemic inflammation. Excessive weight and metabolic disorders in adolescents with PCOS are the most significant factors in reducing the capacity of antioxidant systems, activation of oxidative stress, mitochondrial dysfunction, and systemic inflammation.

Polycystic ovary syndrome is a risk factor for sarcopenic obesity: a case control study

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in young women and increases risk of cardiovascular and metabolic disease, and infertility. Women with PCOS share many characteristics commonly associated with aging including chronic inflammation and insulin resistance, which may be associated with "sarcopenic obesity", a term used to describe low appendicular skeletal muscle mass relative to total body mass. The purpose of this work was to determine the prevalence of sarcopenic obesity in women with PCOS. We hypothesized there would be a high prevalence of sarcopenic obesity, and that % appendicular skeletal muscle mass and markers of inflammation and insulin resistance would be inversely correlated in this population.

METHODS

Dual energy X-ray absorptiometry was used to assess body composition in 68 women with PCOS aged 18-35y and 60 healthy age-matched women from the same geographic area. Sarcopenic obesity was defined as having % appendicular skeletal muscle mass 2 standard deviations below the mean for the healthy age-matched controls and a % body fat above 35%. Data were analyzed with Mann-Whitney U-tests and Spearman correlations.

RESULTS

53% of women with PCOS were classified as sarcopenic obese. Women with PCOS had a median (interquartile range) appendicular skeletal muscle mass of 23.8 (22.3-25.8)% which was lower than the control median of 30.4 (28.6-32.4)% (p < 0.0001). Among women with PCOS, there were negative correlations between % appendicular skeletal muscle mass and the homeostasis model assessment insulin resistance index (r = - 0.409; p < 0.01), high sensitivity C-reactive protein (r = - 0.608; p < 0.0001) and glycosylated hemoglobin (r = - 0.430; p < 0.0001). Furthermore, % appendicular skeletal muscle mass correlated positively with vitamin D (r = 0.398; p < 0.0001) in women with PCOS, which is thought to positively affect skeletal muscle mass.

CONCLUSIONS

Women with PCOS have a high prevalence of sarcopenic obesity, which is correlated to insulin resistance and inflammation.

Association between Trp48Arg polymorphism of the CD11c gene and risk for obesity among Iranian population

Background

Despite assessing the expression of CD11c gene in macrophages in adipose tissues and suggesting association between the gene expressions and predisposing to obesity, the relationship of the changes in CD11c gene and its variants with obesity has not been exclusively evaluated. The present study aimed to assess the relationship between rs2230424 gene polymorphism leading a single amino acid Arginine 48 to Tryptophan interchange in CD11c gene protein chain and obesity in a sample of Iranian population.

Methods

This case-control association study was performed on 247 subjects including obese individuals and a sex- and age-matched healthy non-obese individuals. After DNA extraction, the DNA sequence containing the relevant polymorphic site was amplified by polymerase chain reaction (PCR). Determining different genotypic patterns of the SNP was carried out by restriction fragment length polymorphism (RFLP) analysis. To final draft the suspected genotypes of the SNP, DNA sequencing was performed.

Results

The frequency of wild genotype (TT) of Trp48Arg polymorphism of the CD11c gene in obese and non-obese groups was 97.9% and 94.6% and the frequency of heterozygous genotype (TC) was 2.1% and 5.4%, respectively with no significant difference (p = 0.230,). None of the participants had mutant genotypic pattern of the polymorphism. There was no association of the genotypic pattern of Trp48Arg polymorphism with different underlying risk factors as well as mean laboratory parameters.

Conclusion

The presence of Trp48Arg polymorphism of the CD11c gene is not associated with increased risk for obesity among Iranian population.

The critical role of macrophages in the pathogenesis of hidradenitis suppurativa

INTRODUCTION

Hidradenitis suppurativa (HS) is a painful chronic inflammatory disease with a prevalence between 1 and 4% of general population. The pathogenesis of HS long eluded scientists, but growing evidence suggests that it is a consequence of inflammatory dysregulation.

FINDINGS

Recent studies suggest that dysregulated immune response to skin flora and overexpression of inflammatory cytokines leads to chronic skin inflammation seen in HS. Macrophages are the most numerous inflammatory cells found in HS infiltrates and release numerous pro-inflammatory cytokines such as IL-23, and IL-1β and TNF-α, exacerbating the inflammation and contributing to the pathogenesis of HS. Furthermore, in HS, there is dysregulated function of other immune players closely associated with macrophage function including: matrix metalloproteases (MMP) 2 and 9 overexpression, toll-like receptor upregulation, impaired Notch signalling, NLRP3 inflammasome upregulation, and dysregulated keratinocyte function. Lifestyle factors including obesity and smoking also contribute to macrophage dysfunction and correlate with HS incidence.

CONCLUSIONS

The overexpression of pro-inflammatory cytokines and subsequent efficacy of anti-cytokine biologic therapies highlights the importance of managing macrophage dysfunction. Future therapies should target key molecular drivers of macrophage dysfunction such as TLR2 and NLRP3 overexpression.

High Serum Tumor Necrosis Factor-Alpha Levels in Women with Polycystic Ovary Syndrome: A Meta-Analysis

The objective of the study is to assess the TNF-α levels in PCOS patients and healthy controls. A comprehensive electronic search in Medline, Embase, and the Cochrane Library database was conducted up to July 2016. Random-effects model was used to estimate the standardized mean differences (SMDs) with 95% confidence intervals (CIs). Twenty-nine studies with a total of 1960 participants (1046 PCOS patients and 914 controls) were included in this meta-analysis. The TNF-α levels in PCOS patients were significantly higher than those in controls (random-effects, SMD = 0.60, 95% CI = 0.28-0.92, P<0.001). With regard to the subgroup analyses stratified by ethnicity, study quality, methods, and BMI, significantly high TNF-α levels were found in patients with PCOS in almost all of these subgroups. In the subgroup stratified by HOMA-IR ratio and T ratio, significant differences were only observed in the subgroups with HOMA-IR ratio of >1.72(SMD = 0.967, 95% CI = 0.103-1.831, P = 0.028, I2 = 93.5%) and T ratio>2.10 (SMD = 1.420, 95% CI = 0.429-2.411, P = 0.005, I2 = 96.1%). By meta-regression it was suggested that ethnicity might contribute little to the heterogeneity between the included studies. Through cumulative meta-analysis and sensitivity analysis it was supposed that the higher TNF-α levels of PCOS patients compared to healthy controls was stable and reliable. This meta-analysis suggests that the circulating TNF-α levels in women with PCOS are significantly higher than those in healthy controls. It may be involved in promoting insulin resistance and androgen excess of PCOS.

Adipose Tissue Dendritic Cells Are Independent Contributors to Obesity-Induced Inflammation and Insulin Resistance

Dynamic changes of adipose tissue leukocytes, including adipose tissue macrophage (ATM) and adipose tissue dendritic cells (ATDCs), contribute to obesity-induced inflammation and metabolic disease. However, clear discrimination between ATDC and ATM in adipose tissue has limited progress in the field of immunometabolism. In this study, we use CD64 to distinguish ATM and ATDC, and investigated the temporal and functional changes in these myeloid populations during obesity. Flow cytometry and immunostaining demonstrated that the definition of ATM as F4/80⁺CD11b⁺ cells overlaps with other leukocytes and that CD45⁺CD64⁺ is specific for ATM. The expression of core dendritic cell genes was enriched in CD11c⁺CD64^- cells (ATDC), whereas core macrophage genes were enriched in CD45⁺CD64⁺ cells (ATM). CD11c⁺CD64^- ATDCs expressed MHC class II and costimulatory receptors, and had similar capacity to stimulate CD4⁺ T cell proliferation as ATMs. ATDCs were predominantly CD11b⁺ conventional dendritic cells and made up the bulk of CD11c⁺ cells in adipose tissue with moderate high-fat diet exposure. Mixed chimeric experiments with Ccr2^-/- mice demonstrated that high-fat diet-induced ATM accumulation from monocytes was dependent on CCR2, whereas ATDC accumulation was less CCR2 dependent. ATDC accumulation during obesity was attenuated in Ccr7^-/- mice and was associated with decreased adipose tissue inflammation and insulin resistance. CD45⁺CD64⁺ ATM and CD45⁺CD64^-CD11c⁺ ATDCs were identified in human obese adipose tissue and ATDCs were increased in s.c. adipose tissue compared with omental adipose tissue. These results support a revised strategy for unambiguous delineation of ATM and ATDC, and suggest that ATDCs are independent contributors to adipose tissue inflammation during obesity.

Comprehensive assessment of expression of insulin signaling pathway components in subcutaneous adipose tissue of women with and without polycystic ovary syndrome

Objective

Insulin resistance is a common feature of polycystic ovary syndrome (PCOS). The insulin signaling pathway consists of two major pathways, the metabolic and the mitogenic cascades. The many components of these pathways have not been comprehensively analyzed for differential expression in insulin-responsive tissues in PCOS. The goal of this study was to determine whether the core elements of the insulin signal transduction cascade were differentially expressed in subcutaneous adipose tissue (SAT) between PCOS and controls.

Materials/methods

Quantitative real-time PCR for 36 insulin signaling pathway genes was performed in subcutaneous adipose tissue from 22 white PCOS and 13 healthy controls.

Results

Genes in the insulin signaling pathway were not differentially expressed in subcutaneous adipose tissue between PCOS and controls (P > 0.05 for all). Components mainly of the mitogenic pathway were correlated with both androgens and metabolic phenotypes. Expression levels of five genes (MKNK1, HRAS, NRAS, KRAS, and GSK3A) were positively correlated with total testosterone level (ρ > 0, P < 0.05). Inverse correlation was found between expression of six genes (HRAS, MAP2K2, NRAS, MAPK3, GRB2, and SHC1) and metabolic traits (body mass index, fasting glucose, fasting insulin, and HOMA-IR) (ρ < 0, P < 0.05).

Conclusions

Differential expression of core insulin signaling pathway components in subcutaneous adipose tissue is not a major contributor to the pathogenesis of PCOS. Correlation between clinical phenotypes and expression of several genes in the mitogenic limb of the insulin signaling pathway suggests mitogenic signaling by insulin may regulate steroidogenesis and glucose homeostasis.

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We examined gene expression in adipose tissue between PCOS and controls.

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Complete coverage of core elements of the insulin signaling pathway.

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Differential mRNA expression in adipose tissue is not a major contributor to PCOS.

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We discovered associations between mitogenic signaling components and phenotypes.

Effects of a eucaloric reduced-carbohydrate diet on body composition and fat distribution in women with PCOS

OBJECTIVE

To determine if consumption of a reduced-carbohydrate (CHO) diet would result in preferential loss of adipose tissue under eucaloric conditions, and whether changes in adiposity were associated with changes in postprandial insulin concentration.

METHODS

In a crossover-diet intervention, 30 women with PCOS consumed a reduced-CHO diet (41:19:40% energy from CHO:protein:fat) for 8 weeks and a standard diet (55:18:27) for 8 weeks. Body composition by DXA and fat distribution by CT were assessed at baseline and following each diet phase. Insulin AUC was obtained from a solid meal test (SMT) during each diet phase.

RESULTS

Participants lost 3.7% and 2.2% total fat following the reduced-CHO diet and STD diet, resp. (p<0.05 for difference between diets). The reduced-CHO diet induced a decrease in subcutaneous-abdominal, intra-abdominal, and thigh-intermuscular adipose tissue (-7.1%, -4.6%, and -11.5%, resp.), and the STD diet induced a decrease in total lean mass. Loss of fat mass following the reduced CHO diet arm was associated with lower insulin AUC (p<0.05) during the SMT.

CONCLUSIONS

In women with PCOS, consumption of a diet lower in CHO resulted in preferential loss of fat mass from metabolically harmful adipose depots, whereas a diet high in CHO appeared to promote repartitioning of lean mass to fat mass.

The polycystic ovary syndrome: a position statement from the European Society of Endocrinology

Polycystic ovary syndrome (PCOS) is the most common ovarian disorder associated with androgen excess in women, which justifies the growing interest of endocrinologists. Great efforts have been made in the last 2 decades to define the syndrome. The presence of three different definitions for the diagnosis of PCOS reflects the phenotypic heterogeneity of the syndrome. Major criteria are required for the diagnosis, which in turn identifies different phenotypes according to the combination of different criteria. In addition, the relevant impact of metabolic issues, specifically insulin resistance and obesity, on the pathogenesis of PCOS, and the susceptibility to develop earlier than expected glucose intolerance states, including type 2 diabetes, has supported the notion that these aspects should be considered when defining the PCOS phenotype and planning potential therapeutic strategies in an affected subject. This paper offers a critical endocrine and European perspective on the debate on the definition of PCOS and summarises all major aspects related to aetiological factors, including early life events, potentially involved in the development of the disorder. Diagnostic tools of PCOS are also discussed, with emphasis on the laboratory evaluation of androgens and other potential biomarkers of ovarian and metabolic dysfunctions. We have also paid specific attention to the role of obesity, sleep disorders and neuropsychological aspects of PCOS and on the relevant pathogenetic aspects of cardiovascular risk factors. In addition, we have discussed how to target treatment choices based according to the phenotype and individual patient's needs. Finally, we have suggested potential areas of translational and clinical research for the future with specific emphasis on hormonal and metabolic aspects of PCOS.

Adipose tissue changes in obesity and the impact on metabolic function

Obesity is associated with adverse alterations in adipose tissue that predispose to metabolic dysregulation. These adverse alterations include accumulation of inflammatory macrophages leading to the activation of inflammation pathways, reduction in lipid turnover, and deposition of fat in ectopic locations. These alterations are precursors to the development of insulin resistance and metabolic dysfunction.

Polycystic ovary syndrome, insulin resistance, and obesity: navigating the pathophysiologic labyrinth

Polycystic ovary syndrome (PCOS) is a highly prevalent endocrine-metabolic disorder that implies various severe consequences to female health, including alarming rates of infertility. Although its exact etiology remains elusive, it is known to feature several hormonal disturbances, including hyperandrogenemia, insulin resistance (IR), and hyperinsulinemia. Insulin appears to disrupt all components of the hypothalamus-hypophysis-ovary axis, and ovarian tissue insulin resistance results in impaired metabolic signaling but intact mitogenic and steroidogenic activity, favoring hyperandrogenemia, which appears to be the main culprit of the clinical picture in PCOS. In turn, androgens may lead back to IR by increasing levels of free fatty acids and modifying muscle tissue composition and functionality, perpetuating this IR-hyperinsulinemia-hyperandrogenemia cycle. Nonobese women with PCOS showcase several differential features, with unique biochemical and hormonal profiles. Nevertheless, lean and obese patients have chronic inflammation mediating the long term cardiometabolic complications and comorbidities observed in women with PCOS, including dyslipidemia, metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. Given these severe implications, it is important to thoroughly understand the pathophysiologic interconnections underlying PCOS, in order to provide superior therapeutic strategies and warrant improved quality of life to women with this syndrome.