Insight into Potential Interactions of Thyroid Hormones, Sex Hormones and Their Stimulating Hormones in the Development of Non-Alcoholic Fatty Liver Disease

EMAS position statement: Thyroid disease and menopause

INTRODUCTION

Thyroid diseases are common in women in their late reproductive years; therefore, thyroid disease and menopause may co-exist. Both conditions may present with a wide range of symptoms, leading to diagnostic challenges and delayed diagnosis. Aim To construct the first European Menopause and Andropause Society (EMAS) statement on thyroid diseases and menopause.

MATERIALS AND METHODS

Literature review and consensus of expert opinion (EMAS executive board members/experts on menopause and thyroid disease).

SUMMARY RECOMMENDATIONS

This position paper highlights the diagnostic and therapeutic dilemmas in managing women with thyroid disease during the menopausal transition, aiming to increase healthcare professionals' awareness of thyroid disorders and menopause-related symptoms. Clinical decisions regarding the treatment of both conditions should be made with caution and attention to the specific characteristics of this age group while adopting a personalized patient approach. The latter must include the family history, involvement of the woman in the decision-making, and respect for her preferences, to achieve overall well-being.

Cross-Talk Between Thyroid Disorders and Nonalcoholic Fatty Liver Disease: From Pathophysiology to Therapeutics

The medical community acknowledges the presence of thyroid disorders and nonalcoholic fatty liver disease (NAFLD). Nevertheless, the interconnection between these two circumstances is complex. Thyroid hormones (THs), including triiodothyronine (T3) and thyroxine (T4), and thyroid-stimulating hormone (TSH), are essential for maintaining metabolic balance and controlling the metabolism of lipids and carbohydrates. The therapeutic potential of THs, especially those that target the TRβ receptor isoform, is generating increasing interest. The review explores the pathophysiology of these disorders, specifically examining the impact of THs on the metabolism of lipids in the liver. The purpose of this review is to offer a thorough analysis of the correlation between thyroid disorders and NAFLD, as well as suggest potential therapeutic approaches for the future.

Maternal nutrient metabolism in the liver during pregnancy

The liver plays pivotal roles in nutrient metabolism, and correct hepatic adaptations are required in maternal nutrient metabolism during pregnancy. In this review, hepatic nutrient metabolism, including glucose metabolism, lipid and cholesterol metabolism, and protein and amino acid metabolism, is first addressed. In addition, recent progress on maternal hepatic adaptations in nutrient metabolism during pregnancy is discussed. Finally, the factors that regulate hepatic nutrient metabolism during pregnancy are highlighted, and the factors include follicle-stimulating hormone, estrogen, progesterone, insulin-like growth factor 1, prostaglandins fibroblast growth factor 21, serotonin, growth hormone, adrenocorticotropic hormone, prolactin, thyroid stimulating hormone, melatonin, adrenal hormone, leptin, glucagon-like peptide-1, insulin glucagon and thyroid hormone. Our vision is that more attention should be paid to liver nutrient metabolism during pregnancy, which will be helpful for utilizing nutrient appropriately and efficiently, and avoiding liver diseases during pregnancy.

What Do Higher Alanine Aminotransferase Levels Mean in Premature Ovarian Insufficiency?

The objective of this study was to investigate the relationship between alanine aminotransferase and related biochemical parameters and potential risk factors in women with premature ovarian insufficiency (POI). This is a retrospective cohort study with 126 POI patients (including subclinical POI, n= 27) and 130 healthy controls who visited our clinic between April 2021 to November 2022. Associations were investigated by multiple linear regression, Person correlation analysis, the Kruskal-Wallis test, Mann-Whitney U test, and the independent t-test. When compared to controls, analysis of POI patients showed that body mass index (BMI), uric acid (UA) and urea, alanine aminotransferase (ALT), aspartate aminotransferase (AST), monocyte/lymphocyte ratio, monocyte count (MONO), neutrophil count (NEUT), follicle-stimulating hormone (FSH), luteinizing hormone, and neutrophil/lymphocyte ratio (NLR) were significantly higher, while estradiol (E2), the lymphocyte count and the AST/ALT ratio were lower (P < 0.05). According to linear correlation, it was clear that BMI, FSH, white blood cell count (WBC), NEUT, MONO, UA, AST, and NLR were positively associated with ALT (r = 0.215, 0.388, 0.195, 0.187, 0.184, 0.605, 0.819, and 0.189, respectively, all P < 0.05) while E2 was negatively associated with ALT (r = -0.278, P < 0.05). In addition, multiple linear regression revealed a significant, independent, and positive correlation between AST, FSH, and ALT (B =1.403 and 0.069, respectively, P < 0.05). Analysis revealed that the levels of ALT were significantly higher in POI patients. In addition, BMI, FSH, UA, AST, MONO, NLR, NEUT, and WBC were positively associated with ALT in POI patients. E2 was negatively associated with ALT. Multiple linear regression revealed an independent and positive correlation between AST, FSH, and ALT. In addition, there was also a risk of liver function damage in women with POI and subclinical POI. If patients were diagnosed with POI, early examination and corresponding intervention will be required to effectively prevent the further development of liver disease.

Endocrine aspects of metabolic dysfunction-associated steatotic liver disease (MASLD): Beyond insulin resistance

While the association of metabolic dysfunction-associated steatotic liver disease (MASLD) with obesity and insulin resistance is widely appreciated, there are a host of complex interactions between the liver and other endocrine axes. While it can be difficult to definitively distinguish direct causal relationships and those attributable to increased adipocyte mass, there is substantial evidence of the direct and indirect effects of endocrine dysregulation on the severity of MASLD, with strong evidence that low levels of growth hormone, sex hormones, and thyroid hormone promote the development and progression of disease. The impact of steroid hormones, e.g. cortisol and dehydroepiandrosterone, and adipokines is much more divergent. Thoughtful assessment, based on individual risk factors and findings, and management of non-insulin endocrine axes is essential in the evaluation and management of MASLD. Multiple therapeutic options have emerged that leverage various endocrine axes to reduce the fibroinflammatory cascade in MASH.

[Nonalcoholic fatty liver disease : Hepatic manifestations of metabolic syndrome]

Nonalcoholic fatty liver disease (NAFLD) is nowadays the leading cause of chronic liver disease worldwide and shows a strong association with the metabolic syndrome. The NAFLD is a systemic disease associated with a plethora of extrahepatic manifestations and comorbidities, such as type 2 diabetes, obesity and dyslipidemia. These extrahepatic disorders are related either to secondary effects of the associated obesity or to pathophysiological effects of insulin resistance in NAFLD. The three most common causes of the observed increased morbidity and mortality associated with NAFLD are cardiovascular diseases, liver diseases, such as cirrhosis, and cancer. In this overview, cardiovascular diseases, type 2 diabetes mellitus and chronic kidney diseases in connection with NAFLD are discussed as examples, as well as tumor entities, in particular colon cancer, lung diseases (obstructive sleep apnea), endocrine diseases (hypothyroidism) and systemic phenomena associated with NAFLD (e.g. iron overload and thrombophilia). In addition to focusing on the pathogenesis of these extrahepatic manifestations, the clinical implications are highlighted. So far there are no drugs approved for the indication NAFLD in Germany. The new NAFLD S2k guidelines offer a way out of the current "therapeutic nihilism". Diagnostic and therapeutic algorithms based on the metabolic comorbidities and the stage of fibrosis are designed with practical relevance and can be used in everyday medical practice. Therefore, clear basic measures and drug recommendations can be given for NAFLD depending on the comorbidities and stage of fibrosis.

Menopause is associated with increased prevalence of nonalcoholic fatty liver disease: a systematic review and meta-analysis

IMPORTANCE

Data are inconsistent on whether menopause is a risk for nonalcoholic fatty liver disease (NAFLD).

OBJECTIVE

Using systematic review and meta-analysis, we aimed to collect all available data to determine the association between menopause and NAFLD.

EVIDENCE REVIEW

Potentially eligible studies were identified from EMBASE, MEDLINE, and Web of Science databases from inception to December 2021 using a search strategy that was composed of the terms for "NAFLD" and "menopause." Eligible study must contain two groups of participants: one group of postmenopausal women and another group of premenopausal women. Then, the study must report the association between menopause and prevalent NAFLD. We extracted such data from each study and calculated pooled odds ratio (OR) by combining effect estimates of each study using a random-effects model. Funnel plot was used to assess for the presence of publication bias.

FINDINGS

A total of 587 articles were identified. After two rounds of independent review by two investigators, 12 cross-sectional studies fulfilled the eligibility criteria. The meta-analysis of 12 studies revealed the significant association between menopause and NAFLD with a pooled OR of 2.37 (95% CI, 1.99-2.82; I2 = 73%). The association remained significant in a sensitivity meta-analysis of six studies that reported the association with adjustment for age and metabolic factors with a pooled OR of 2.19 (95% CI, 1.73-2.78; I2 = 74%). The funnel plot was fairly symmetric and was not suggestive of publication bias.

CONCLUSIONS AND RELEVANCE

The meta-analysis reveals that menopausal status was associated with approximately 2.4 times higher odds of NAFLD.

Icariin Alleviates Nonalcoholic Fatty Liver Disease in Polycystic Ovary Syndrome by Improving Liver Fatty Acid Oxidation and Inhibiting Lipid Accumulation

(1) Background: Icariin is the main component of the Chinese herb Epimedium. A number of studies have shown that it alleviates abnormal lipid metabolism. However, it is not clear whether and how icariin can ameliorate hepatic steatosis with polycystic ovary syndrome (PCOS). This study was designed to explore the anti-hepatosteatosis effect of icariin in rats with polycystic ovary syndrome. (2) Methods: Female Sprague Dawley(SD)rats were treated with a high-fat diet and letrozole for 21 days to make nonalcoholic fatty liver disease (NAFLD) in the polycystic ovary syndrome model. Then model rats were treated with icariin (by gavage, once daily) for 28 days. Serum hormones and biochemical variables were determined by ELISA or enzyme. RNA-sequence analysis was used to enrich related target pathways. Then, quantitative Real-time PCR (qRT-PCR) and Western blot were performed to verify target genes and proteins. (3) Results: Icariin treatment reduced excess serum levels of Testosterone (T), Estradiol (E2), Luteinizing hormone (LH), Follicle-stimulating hormone (FSH), LH/FSH ratio, insulin, triglycerides (TG), and aspartate aminotransferase (AST) in high-fat diet (HFD) and letrozole fed rats. Meanwhile, icariin ameliorated HFD and letrozole-induced fatty liver, as evidenced by a reduction in excess triglyceride accumulation, vacuolization, and Oil Red O staining area in the liver of model rats. Results of RNA-sequencing, western blotting, and qRT-PCR analyses indicated that icariin up-regulated fatty acid translocase (CD36), in mitochondria, and peroxisome proliferator-activated receptor α (PPARα) expression, which led to the enhancement of fatty acid oxidation molecules, such as cytochrome P450, family 4, subfamily a, polypeptide 3 (CYP4A3), carnitine palmitoyltransferase 1 α (CPT1α), acyl-CoA oxidase 1 (ACOX1), medium-chain acyl-CoA dehydrogenase (MCAD), and long-chain acyl-CoA dehydrogenase (LCAD). Besides, icariin reduced lipid synthesis, which elicited stearoyl-Coenzyme A desaturase 1 (SCD1), fatty acid synthase (FASN), and acetyl-CoA (ACC). (4) Conclusion: Icariin showed an ameliorative effect on hepatic steatosis induced by HFD and letrozole, which was associated with improved fatty acid oxidation and reduced lipid accumulation in the liver.