Non-alcoholic fatty liver disease in women with polycystic ovary syndrome - clinical and metabolic aspects and lipoprotein lipase gene polymorphism

Effects of the Pituitary-targeted Gland Axes on Hepatic Lipid Homeostasis in Endocrine-associated Fatty Liver Disease-A Concept Worth Revisiting

Hepatic lipid homeostasis is not only essential for maintaining normal cellular and systemic metabolic function but is also closely related to the steatosis of the liver. The controversy over the nomenclature of non-alcoholic fatty liver disease (NAFLD) in the past three years has once again sparked in-depth discussions on the pathogenesis of this disease and its impact on systemic metabolism. Pituitary-targeted gland axes (PTGA), an important hormone-regulating system, are indispensable in lipid homeostasis. This review focuses on the roles of thyroid hormones, adrenal hormones, sex hormones, and their receptors in hepatic lipid homeostasis, and summarizes recent research on pituitary target gland axes-related drugs regulating hepatic lipid metabolism. It also calls on researchers and clinicians to recognize the concept of endocrine-associated fatty liver disease (EAFLD) and to re-examine human lipid metabolism from the macroscopic perspective of homeostatic balance.

Transcriptomic profile of GLCs of PCOS women highlights metabolic dysregulation as a plausible contributor to PCOS pathophysiology

Polycystic ovary syndrome (PCOS) is a complex heterogeneous disorder with reproductive and metabolic consequences whose aetiology is still elusive. To understand the cellular mechanisms that potentially govern follicular defect in women with PCOS, we performed transcriptomic profiles of granulosa-lutein cells (GLCs) by RNA-Seq analysis. We found differential expression of 876 genes in GLCs between PCOS and controls that belonged to various processes such as cell cycle, extracellular matrix organization, angiogenesis, oxidative stress, metabolism, etc. that support folliculogenesis, oocyte development, and maturation. The cross-talk between oocyte and GLCs is a fundamental cornerstone in determining oocyte quality and highly interlinked pathways of metabolism and redox homeostasis may influence this. We found several genes involved in the metabolism of carbohydrates, nucleotides, cholesterol, and lipids were dysregulated, which may impair the supply of metabolites to the growing oocyte, affecting oocyte development and competence. Additionally, high metabolic activity during folliculogenesis may augment oxidative damage to cells and macromolecules if not counter-balanced. We observed dysregulation of redox homeostasis and AGE-RAGE signalling in the follicular environment. Among the validated genes, prokineticin-1 and growth differentiation factor-15 were found to be negatively regulated, while, S100, calcium-binding protein A9 and angiomotin-like-2 were positively regulated in GLCs of women with PCOS. Comparing our data with previously published relevant transcriptomic studies showed metabolic, cytokine-cytokine receptor interaction, IL-17, and chemokine signalling pathways were most commonly affected in PCOS. Overall, this data can provide insights into mechanisms contributing to PCOS pathophysiology and can be explored as potential indicators for oocyte/embryo quality in IVF settings.

Non-alcoholic fatty liver disease across endocrinopathies: Interaction with sex hormones

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most frequent chronic liver disease globally. NAFLD is strongly associated with metabolic syndrome and it has been recently suggested that to rename NAFLD as metabolic dysfunction-associated fatty liver disease (MAFLD). NAFLD has been studied in different endocrine axes and accumulating body of clinical and experimental studies have suggested that NAFLD is associated with polycystic ovarian syndrome (PCOS), hypopituitarism, growth hormone deficiency (GHD), hypogonadism and other endocrine disorders. In fact, endocrine dysfunction may be considered as the major contributor for the development, progression, and severity of NAFLD. In the present comprehensive review, we discussed the epidemiological and clinical evidence on the epidemiology, pathophysiology, and management of NAFLD in endocrine disorders, with an emphasis on the effects of sex-specific hormones/conditions as well as molecular basis of NAFLD development in these endocrine diseases.

Revisiting the physiological role of androgens in women

INTRODUCTION

Extensive research underlines the critical functions of androgens in females. Nevertheless, the precise mechanisms of their action are poorly understood. Here, we review the existing literature regarding the physiological role of androgens in women throughout life.

AREAS COVERED

Several studies show that androgen receptors (ARs) are broadly expressed in numerous female tissues. They are essential for many physiological processes, including reproductive, sexual, cardiovascular, bone, muscle, and brain health. They are also involved in adipose tissue and liver function. Androgen levels change with the menstrual cycle and decrease in the first decades of life, independently of menopause.

EXPERT OPINION

To date, studies are limited by including small numbers of women, the difficulty of dosing androgens, and their cyclical variations. In particular, whether androgens play any significant role in regulating the establishment of pregnancy is poorly understood. The neural functions of ARs have also been investigated less thoroughly, although it is expressed at high levels in brain structures. Moreover, the mechanism underlying the decline of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) with age is unclear. Other factors, including estrogen's effect on adrenal androgen production, reciprocal regulation of ARs, and non-classical effects of androgens, remain to be determined.

A Systematic Review of the Risk of Non-alcoholic Fatty Liver Disease in Women With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a complex hormonal disorder associated with complications throughout various body organs. Previous studies have shown evidence of liver disease in some women with PCOS. In this study, we attempted to explore the risk of non-alcoholic fatty liver disease (NAFLD) in PCOS women and the specific factors involved in its development. We searched PubMed, PubMed Central, Medline, and ScienceDirect for articles related to the topic, screened those articles according to our inclusion/exclusion criteria, and conducted a thorough quality check using various quality appraisal tools to select articles relevant to our research. The process was conducted according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) Checklist 2020.

We selected 11 high-quality observational studies for our review. Studies from various countries were included, and all studies demonstrated an increased prevalence of NAFLD in PCOS patients compared to healthy controls. Although insulin resistance, obesity, and increased androgens contribute to the increase in the risk of NAFLD in these patients, hyperandrogenism was the most influential risk factor in four of these studies. Two studies explored the degree of NAFLD in these patients using transient elastography (TE). They concluded that PCOS was significantly associated with hepatic steatosis (HS) rather than hepatic fibrosis in most patients. PCOS patients have an increased risk of developing NAFLD, particularly HS, and hyperandrogenism seems to be the main determinant. Therefore, effort should be put into screening and monitoring these patients to manage the disease. TE may be a useful method for monitoring the natural history of NAFLD in these patients, which requires further exploration.

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

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

Nonalcoholic Fatty Liver Disease in Women and Girls With Polycystic Ovary Syndrome

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) describes a spectrum of liver damage due to excessive hepatic lipid accumulation. Recent research has demonstrated a high prevalence of NAFLD in women with polycystic ovary syndrome (PCOS).

RESULTS

Strong associations independent of body mass index (BMI) have been found between high androgen levels characteristic of PCOS, as well as insulin resistance, and the presence of NAFLD in these women, suggesting that these factors contribute to liver injury more significantly than obesity. Current studies indicate the occurrence of NAFLD in normal weight women with PCOS in addition to the commonly researched women who are overweight and obese. While the majority of studies address NAFLD in adult, premenopausal women (ages 25-40 years), the occurrence of NAFLD in young and adolescent women has gone largely unaddressed. Research in this field lacks diversity; a majority of studies either focus on populations of White women or are missing demographic information entirely.

CONCLUSIONS

Future studies should include larger, more racially and ethnically inclusive populations and particular attention should be paid to how excess androgens and insulin resistance contribute to the increased risk of NAFLD seen in women with PCOS of varying weights, ages, and ethnicities.

OBJECTIVE AND METHODS

Here, we review NAFLD in women with PCOS with subsections focused on the impact of hyperandrogenism, BMI, insulin resistance and age. Most notably, we present the most up-to-date racially and ethnically diverse worldwide prevalence of NAFLD in women with PCOS compared with women without PCOS (51.56% vs 29.64%, P < .001, respectively).

Non-alcoholic fatty liver disease in premenopausal women with polycystic ovary syndrome: A systematic review and meta-analysis

Background and Aim

Non‐alcoholic fatty liver disease (NAFLD) and polycystic ovary syndrome (PCOS) are prevalent conditions sharing common pathogenic factors. We performed a systematic literature review and meta‐analysis aiming to investigate the association between NAFLD and PCOS among premenopausal PCOS patients.

Methods

Relevant studies were systematically identified from scientific databases until 2019. We calculated pooled odds ratio (OR) using a random‐effect model, and heterogeneity was addressed through I². Subgroup analyses and meta‐regression for various covariates were performed.

Results

Of the 1833 studies retrieved, 23 studies with 7148 participants qualified for quantitative synthesis. The pooled result showed that women with PCOS had a 2.5‐fold increase in the risk of NAFLD compared to controls (pooled OR 2.49, 95% confidence interval [CI] 2.20–2.82). In subgroup analyses comparing PCOS to controls, South American/Middle East PCOS patients had a greater risk of NAFLD (OR 3.55, 95% CI 2.27–5.55) compared to their counterpart from Europe (OR 2.22, 95% CI 1.85–2.67) and Asia (OR 2.63, 95% CI 2.20–3.15). Insulin resistance and metabolic syndrome were more frequent in the PCOS group (OR 1.97, 95% CI 1.44–2.71 and OR 3.39, 95% CI 2.42–4.76, respectively). Study quality and body mass index (BMI) were the only covariates that showed a relationship with the outcome in the meta‐regression, with a regression coefficient of −2.219 (95% CI −3.927 to −0.511) and −1.929 (95% CI −3.776 to −0.0826), respectively.

Conclusions

This meta‐analysis indicates that premenopausal PCOS patients are associated with 2.5‐fold increase in the risk of NAFLD, and BMI seems to be the main cofactor.

Sex Hormone-Dependent Physiology and Diseases of Liver

Sexual dimorphism is associated not only with somatic and behavioral differences between men and women, but also with physiological differences reflected in organ metabolism. Genes regulated by sex hormones differ in expression in various tissues, which is especially important in the case of liver metabolism, with the liver being a target organ for sex hormones as its cells express estrogen receptors (ERs: ERα, also known as ESR1 or NR3A; ERβ; GPER (G protein-coupled ER, also known as GPR 30)) and the androgen receptor (AR) in both men and women. Differences in sex hormone levels and sex hormone-specific gene expression are mentioned as some of the main variations in causes of the incidence of hepatic diseases; for example, hepatocellular carcinoma (HCC) is more common in men, while women have an increased risk of autoimmune liver disease and show more acute liver failure symptoms in alcoholic liver disease. In non-alcoholic fatty liver disease (NAFLD), the distinction is less pronounced, but increased incidences are suggested among men and postmenopausal women, probably due to an increased tendency towards visceral fat accumulation.

Abdominal Obesity as a Predictive Factor of Nonalcoholic Fatty Liver Disease Assessed by Ultrasonography and Transient Elastography in Polycystic Ovary Syndrome and Healthy Women

Polycystic ovary syndrome (PCOS) and nonalcoholic fatty liver (NAFLD) share similar clinical presentations including obesity, insulin resistance (IR), and metabolic abnormality. The predictive factors of NAFLD in women with PCOS and specifically in Asian women are not well established. Associated factors for NAFLD assessed by ultrasound (US) among a group of PCOS and healthy women were determined and diagnostic accuracy between US and transient elastography (TE) for NAFLD was compared and correlated. Sixty-three women with ages ranging from 20 to 40 years participated in the present cross-sectional study. Forty-two women with PCOS as diagnosed by the Rotterdam criteria and 21 healthy women were recruited into the study. Women with underlying hepatic diseases and history of alcohol consumption >20 g/day were excluded. Biochemical and hormonal testing, anthropometrics, liver US, and TE were assessed. Waist circumference (WC) greater than 80 cm was the only predictive factor for NAFLD as assessed by US in the whole group (adjusted odds ratio [aOR] 5.49, 95% confidence interval [CI]: 1.85–16.26, p <0.001). The value of the TE-based controlled attenuation parameter (CAP) was significantly correlated with stage of steatosis as assessed by US (correlation coefficient = 0.696, p <0.001). The diagnostic accuracies of dichotomized CAP ≥236 dB/m assessed for NAFLD using US as the gold standard were 84% and 78% sensitivity and specificity, respectively, with the area under the curve at 0.81 (p <0.001). Abdominal obesity, rather than the presence of PCOS, was shown to be the independently associated factor for NAFLD. WC could be used as the primary screening tool before performing complicated intervention for detection of steatosis. TE is an alternative noninvasive detection tool in women with PCOS for NAFLD and hepatic fibrosis identification.

Insulin resistance and hyperandrogenemia independently predict nonalcoholic fatty liver disease in women with polycystic ovary syndrome

AIMS

To find the prevalence and predictors of nonalcoholic fatty liver disease (NAFLD) in Asian Indian polycystic ovary syndrome (PCOS) women.

MATERIALS AND METHODS

This is a prospective, cross-sectional study conducted at a tertiary care hospital from South India. Sixty women fulfilling the Rotterdam (2003) criteria for PCOS were recruited for the study. All participants were evaluated with ultrasound abdomen for fatty liver and additional biochemical investigations including fasting plasma glucose, postprandial plasma glucose, serum insulin, lipid profile and liver function tests.

RESULTS

The mean age of the study population was 24.06 ± 5.9 (range: 15-39) years. Oligomenorrhea, hirsutism and acne were present in 58 (96.7%), 37 (61.7%) and 33 (55%) women. Mean BMI of the study population was 29.5 ± 5.28 (range: 19.95 to 45.44) kg/m². Fifty (83.3%) women were obese (BMI: ≥ 25 kg/m²). Twenty-three (38.3%) women with PCOS had NAFLD. Three women each had isolated elevation of alanine transaminase (ALT) and aspartate transaminases (AST) whereas three women had elevation of both. All women with elevated transaminases had NAFLD. By univariate analysis, factors associated with NAFLD were serum total cholesterol, serum insulin, HOMA-IR, hyperandrogenism, ALT and AST. On multiple regression analysis using linear regression, HOMA-IR and hyperandrogenemia were the only significant predictors of NAFLD.

CONCLUSION

Our study reports NAFLD in more than one third of Asian Indian women with PCOS. In addition to insulin resistance (HOMA-IR), hyperandrogenemia is an independent predictor of NAFLD in women with PCOS.

A potential link between polycystic ovary syndrome and non-alcoholic fatty liver disease: an update meta-analysis

BACKGROUND

Epidemiological literature regarding the effect of polycystic ovary syndrome (PCOS) as a risk factor for non-alcoholic fatty liver disease (NAFLD) remains inconsistent. Furthermore, it remains debatable whether NAFLD is associated with PCOS as a consequence of shared risk factors or whether PCOS contributes to NAFLD in an independent fashion. Therefore, this meta-analysis was conducted.

METHODS

This meta-analysis was conducted in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Relevant studies published before May 2017 were identified and retrieved from PubMed and Web of Science databases. The data were extracted, and the pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

A total of 17 studies were included into the present analysis. Compared to the control group, the risk of NAFLD in the PCOS group was higher (OR = 2.25, 95% CI = 1.95-2.60). When stratified by BMI and geographic location, the results indicated that the frequency of NAFLD risk was significantly higher in obese subjects (OR = 3.01, 95% CI = 1.88-4.82), non-obese subjects (OR = 2.07, 95% CI = 1.12-3.85), subjects from Europe (OR = 2.00, 95% CI = 1.58-2.52), subjects from the Asia-Pacific Region, (OR = 2.32, 95% CI = 1.89-2.84) and subjects from America (OR = 2.96, 95% CI = 1.93-4.55). In addition, PCOS patients with hyperandrogenism (HA) had a significantly higher risk of NAFLD, compared with controls (OR = 3.31, 95% CI = 2.58-4.24). However, there was no association between PCOS patients without HA and higher risk of NAFLD (OR = 1.46; 95% CI =0.55-3.87). The results of this meta-analysis should be interpreted with caution due to the small number of observational studies and possible confounding factors.

CONCLUSION

The meta-analysis results suggest that PCOS is significantly associated with high risk of NAFLD. Although this association was independent of obesity and geographic region, it might be correlated with HA.

Non-alcoholic fatty liver disease in women with polycystic ovary syndrome: systematic review and meta-analysis

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) is an insidious pathologic condition that can manifest from simple steatosis to steatohepatitis (NASH) with potential progression to cirrhosis. Like the polycystic ovary syndrome (PCOS), NAFLD is associated with obesity, diabetes mellitus, insulin resistance and metabolic syndrome. PCOS women have an increased risk of NAFLD, but it is debatable which features of PCOS, either specific (androgen excess) or unspecific (metabolic derangements) affect the NAFLD risk.

METHODS

We performed a systematic review and meta-analysis of studies that addressed the association of PCOS and NAFLD. We selected 17 studies published between 2007 and 2017 that included 2734 PCOS patients and 2561 controls of similar age and body mass index (BMI).

RESULTS

PCOS patients have increased prevalence of NAFLD (odds ratio 2.54, 95% confidence interval 2.19-2.95). PCOS women with hyperandrogenism (classic phenotype) have a higher prevalence of NAFLD compared to women with PCOS without hyperandrogenism, even after correction for confounding variables. Among women with PCOS, those with NAFLD have higher serum total testosterone (mean difference 0.40 nmol/L, 95% CI 0.29-0.50 nmol/L) and free androgen index (mean difference 4.46, 95% CI 3.53-5.39) than those without NAFLD. The studies that used multivariate analysis controlling for age, BMI, triglycerides, and insulin resistance index confirmed that serum androgens are independent predictors of NAFLD in women with PCOS.

CONCLUSION

The prevalence of NAFLD is increased in women with PCOS and the presence of NAFLD is associated with high serum androgen levels, in addition to obesity and insulin resistance.

High-free androgen index is associated with increased risk of non-alcoholic fatty liver disease in women with polycystic ovary syndrome, independent of obesity and insulin resistance

BACKGROUND/OBJECTIVE

Central obesity and insulin resistance (IR) are common conditions in women with polycystic ovary syndrome (PCOS) and in subjects with non-alcoholic fatty liver disease (NAFLD). However, few studies have addressed the association between hyperandrogenism (HA) and NAFLD. We aimed to determine whether variations in the free androgen index (FAI) might be associated with NAFLD prevalence.

SUBJECTS/METHODS

A cross-sectional study was performed including 400 Chinese women with PCOS and 100 age, and body mass index (BMI)-matched women. The anthropometric and serum biochemical parameters related to sex steroids, glucose and lipid profiles were examined. Liver fat content (LFC) was measured by quantitative ultrasound.

RESULTS

The prevalence of NAFLD was 56.23% in PCOS patients and 38% in controls (P=0.001), and this prevalence increased with FAI quartile independently of obesity and homeostasis model assessment of insulin resistance (HOMA-IR). The FAI level increased from non-NAFLD group to NAFLD group. The FAI was positively associated with the metabolic parameters LFC, BMI, waist circumference, alanine aminotransferases, aspartate, triglyceride, total cholesterol and low-density lipoprotein cholesterol, and was negatively associated with high-density lipoprotein. Moreover, in multivariate logistic regression analysis BMI, high-sensitivity C-reactive protein (hsCRP), FAI, LFC and HOMA-IR were significantly associated with NAFLD. The cut-off values of FAI, LFC, BMI and hsCRP to predict NAFLD were 9.86%, 17.19%, 24.38% and 0.72%, respectively. The area under the curve for predicting NAFLD in PCOS patients showed comparable sensitivity and specificity between BMI and a new index combining FAI with hsCRP.

CONCLUSIONS

A higher FAI level is associated with increased LFC and NAFLD prevalence independent of obesity and IR.

Sex Hormones and Their Receptors Regulate Liver Energy Homeostasis

The liver is one of the most essential organs involved in the regulation of energy homeostasis. Hepatic steatosis, a major manifestation of metabolic syndrome, is associated with imbalance between lipid formation and breakdown, glucose production and catabolism, and cholesterol synthesis and secretion. Epidemiological studies show sex difference in the prevalence in fatty liver disease and suggest that sex hormones may play vital roles in regulating hepatic steatosis. In this review, we summarize current literature and discuss the role of estrogens and androgens and the mechanisms through which estrogen receptors and androgen receptors regulate lipid and glucose metabolism in the liver. In females, estradiol regulates liver metabolism via estrogen receptors by decreasing lipogenesis, gluconeogenesis, and fatty acid uptake, while enhancing lipolysis, cholesterol secretion, and glucose catabolism. In males, testosterone works via androgen receptors to increase insulin receptor expression and glycogen synthesis, decrease glucose uptake and lipogenesis, and promote cholesterol storage in the liver. These recent integrated concepts suggest that sex hormone receptors could be potential promising targets for the prevention of hepatic steatosis.