Sexual Dimorphism of NAFLD in Adults. Focus on Clinical Aspects and Implications for Practice and Translational Research

Expression of Vascular Adhesion Protein-1 and Thrombospondin-1 in Gingival Crevicular Fluid of Patients with Periodontitis and Non-Alcoholic Fatty Liver Disease

Purpose

Non-alcoholic fatty liver disease (NAFLD) represents a heterogeneous spectrum of liver diseases that encompass simple steatosis, non-alcoholic steatohepatitis (NASH), and advanced fibrosis or cirrhosis. Periodontitis is a chronic infectious disease with multiple causal factors that presents a complex interaction between the microbial biofilm and the host's immune response. The aim of this study was to investigate the concentrations of Vascular Adhesion Protein-1 (VAP-1) and Thrombospondin-1 (TSP-1) in patients with coexisting periodontitis and NAFLD.

Patients and Methods

This study included 48 patients, who were dental and periodontal assessed. Of these patients, 25 were diagnosed with NAFLD. After performing the periodontal clinical examination, gingival crevicular fluid (GCF) samples were collected. Enzyme-linked immunosorbent assay (ELISA) dedicated kits tests were used for the detection and quantitative determination of VAP-1 and TSP-1 in GCF samples. Statistical methods were applied for the comparison and correlation of data.

Results

VAP-1 and TSP-1 levels showed significant differences between all test and control groups (p<0.0001). Statistically significant correlations (p<0.05) between VAP-1 and periodontal and liver parameters were found in patients with NAFLD and periodontitis.

Conclusion

Periodontal inflammation is more marked in patients with periodontitis-NAFLD association. Vascular adhesion and angiogenesis could be affected in patients with periodontitis and NAFLD. These findings could suggest that addressing periodontal inflammation in individuals with the periodontitis-NAFLD association may have a broader impact on vascular adhesion and angiogenesis, highlighting the interplay between oral health and liver conditions for comprehensive patient care.

Global prevalence of nonalcoholic fatty liver disease: an updated meta-analysis on 78 million population over 38 countries

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a global health challenge, with a rising rate in line with other metabolic diseases. We aimed to assess the global prevalence of NAFLD in adult and pediatric populations.

METHODS

PubMed, Scopus and Web of Science databases were systematically searched up to May 2023. Heterogeneity was assessed using Cochran's Q test and I2 statistics, and random-effects model was used for meta-analysis. Analyses were performed using STATA version 18.

RESULTS

A total of 479 studies with 78,001,755 participants from 38 countries were finally included. The global prevalence of NAFLD was estimated to be 30.2% (95% CI: 28.7-31.7%). Regionally, the prevalence of NAFLD was as follows: Asia 30.9% (95% CI: 29.2-32.6%), Australia 16.1% (95% CI: 9.0-24.8%), Europe 30.2% (95% CI: 25.6-35.0%), North America 29% (95% CI: 25.8-32.3%), and South America 34% (95% CI: 16.9-53.5%). Countries with a higher human development index (HDI) had significantly lower prevalence of NAFLD (coefficient = -0.523, p = 0.005). Globally, the prevalence of NAFLD in men and women was 36.6% (95% CI: 34.7-38.4%) and 25.5% (95% CI: 23.9-27.1%), respectively. The prevalence of NAFLD in adults, adults with obesity, children, and children with obesity was 30.2% (95% CI: 28.8-31.7%), 57.5% (95% CI: 43.6-70.9%), 14.3% (95% CI: 10.3-18.8%), and 38.0% (95% CI: 31.5-44.7%), respectively.

CONCLUSION

The prevalence of NAFLD is remarkably high, particularly in countries with lower HDI. This substantial prevalence in both adults and children underscores the need for disease management protocols to reduce the burden.

Childhood maltreatment and risk of metabolic dysfunction-associated steatotic liver disease - Evidence of sex-specific associations in the general population

BACKGROUND AND AIMS

Childhood maltreatment (CM) is linked to self-reported liver disease in adulthood. However, specific diagnostic entities, e.g., metabolic dysfunction-associated steatotic liver disease (MASLD) as the most frequent chronic liver disease, and sex-differences have previously not been considered.

METHODS

Cross-sectional analyses were conducted in 4188 adults from a population-based cohort in Northeastern Germany after excluding individuals with excessive alcohol consumption, cirrhosis, or chronic viral hepatitis. CM-exposure was assessed using the Childhood Trauma Questionnaire (CTQ). Liver-related outcomes included serologic liver enzymes, fibrosis-4 score (FIB-4) and, in 1863 subjects who underwent magnetic resonance imaging examination, liver fat content. Sex-stratified linear regression and logistic regression models predicting liver-related outcomes and risk for MASLD, respectively, from overall CTQ scores were adjusted for age, school education, alcohol consumption, and waist circumference. Exploratory analyses investigated effects of CTQ-subscales on liver-related outcomes and risk for MASLD.

RESULTS

In both sexes, overall CM-exposure was associated with higher levels of serum aspartate aminotransferase and FIB-4 score. In men, effects were mainly driven by physical abuse, and in women by emotional neglect. Only in men, overall CM-exposure (β = 0.70, 95%-CI 0.26-1.13, p = 0.002) and four CTQ-subscales were associated with greater liver fat content, and physical abuse (aOR = 1.22, 95%-CI 1.02-1.46, p = 0.034) and physical neglect (aOR = 1.25, 95%-CI 1.04-1.49, p = 0.015) were associated with higher risk for MASLD.

CONCLUSIONS

These results suggest sex differences in the association between CM and objective serum and imaging markers of MASLD in adulthood. For men especially, a history of CM-exposure may increase risk of developing MASLD in adulthood.

Gender-Affirming Hormone Treatment and Metabolic Syndrome Among Transgender Veterans

Importance

Gender-affirming hormone treatment (GAHT) is a common therapy for transgender individuals to reduce gender dysphoria and improve quality of life. Clarifying the long-term effects of GAHT remains a priority in transgender health research.

Objective

To explore whether sex hormones (estradiol and testosterone) are associated with the development of metabolic syndrome in transgender veterans compared with cisgender veterans.

Design, Setting, and Participants

This retrospective, longitudinal cohort study used International Classification of Diseases, Ninth Revision and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnosis codes for gender dysphoria from the Veterans Health Administration national database to identify transfeminine and transmasculine veterans receiving documented feminizing (estradiol) or masculinizing (testosterone) treatment from January 1, 2006, to December 31, 2019, and for whom the GAHT initiation date and metabolic syndrome component-related data were available. Transgender veterans were matched to cisgender referents.

Exposure

Gender-affirming hormone treatment.

Main Outcomes and Measures

Metabolic syndrome z-scores were calculated based on body mass index, systolic blood pressure, and levels of high-density lipoprotein cholesterol, triglycerides, and blood glucose. Changes in mean z-scores were compared among the transgender and cisgender groups before and after the index date (corresponding to GAHT initiation) using a repeated-measures analysis of variance model.

Results

The cohort included 1290 participants: 645 transgender (494 [38.3%] transfeminine, 151 [11.7%] transmasculine) and 645 cisgender (280 [21.7%] female, 365 [28.3%] male). Mean (SD) age at the index date was 41.3 (13.2) years. Metabolic syndrome z-scores changed significantly over time and differed significantly across groups. Overall, transmasculine veterans had the greatest percentage increase in mean (SEM) z-scores after vs before the index date (298.0% [57.0%]; P < .001), followed by cisgender females (108.3% [27.5%]; P < .001), cisgender males (49.3% [27.5%]; P = .02), and transfeminine persons (3.0% [10.7%]; P = .77).

Conclusions and Relevance

In this cohort study, in both cisgender and transgender veterans, estradiol was associated with reduced metabolic syndrome risk, whereas testosterone was associated with increased risk. However, transmasculine individuals had the greatest risk and transfeminine individuals had the lowest risk of metabolic syndrome associated with these hormones. This is relevant for the management of metabolic syndrome risk factors in cisgender and transgender individuals and to potentially predict the risk of atherosclerotic cardiovascular disease, type 2 diabetes, systolic hypertension, insulin resistance, and nonalcoholic fatty liver disease.

Does an Aspirin a Day Take the MASLD Away?

Although aspirin is deeply rooted in the most ancient history of medicine, the mechanism of action of this drug was only identified a few decades ago. Aspirin has several indications ranging from its long-known analgesic and antipyretic properties to the more recently discovered antithrombotic, chemopreventive and anti-eclampsia actions. In addition, a recent line of research has identified aspirin as a drug with potential hepatologic indications. This article specifically focuses on the nonalcoholic fatty liver disease/nonalcoholic metabolic dysfunction fatty liver disease/metabolic dysfunction-associated steatotic liver disease (NAFLD/MAFLD/MASLD) field. To this end, the most recently published randomized controlled trial on aspirin for non-cirrhotic MASLD is summarized and discussed. Moreover, previous epidemiologic evidence supporting the notion that aspirin exerts antisteatotic and antifibrotic hepatic effects, which may result in the primary prevention of hepatocellular carcinoma, is also addressed. Next, the putative mechanisms involved are examined, with reference to the effects on adipose tissue and liver and sex differences in the action of aspirin. It is concluded that these novel findings on aspirin as a "hepatologic drug" deserve additional in-depth evaluation.

Sex-specific differences in ectopic fat and metabolic characteristics of paediatric nonalcoholic fatty liver disease

BACKGROUND/OBJECTIVES

Sex-specific differences in obesity-related metabolic characteristics of non-alcoholic fatty liver disease (NAFLD) have rarely been explored, particularly in children with biopsy-verified NAFLD. The influence of sex hormones on ectopic fat disposition may cause inter-sex differences in various metabolic factors. This study aimed to assess the sex-based differences in ectopic fat and metabolic characteristics in children with NAFLD.

SUBJECT/METHODS

We enrolled 63 children with biopsy-verified NAFLD (48 boys; mean age, 12.9 ± 3.2 years; mean body mass index z-score [BMI-z], 2.49 ± 1.21). Ectopic fat in the liver and pancreas was quantified based on magnetic resonance imaging within 2 days of the liver biopsy. Laboratory tests, body composition, blood pressure, and anthropometric measurements were also assessed.

RESULTS

Sex-based differences were neither observed in age, BMI-z, or total body fat percentage nor in the proportions of obesity, abdominal obesity, diabetes, dyslipidaemia, hypertension, or metabolic syndrome. Furthermore, liver enzyme levels, lipid profiles, and pancreatic fat did not differ between the sexes. However, boys had significantly higher fasting insulin (median 133.2 vs. 97.8 pmol/L; p = 0.039), fasting plasma glucose (median 5.30 vs. 4.83 mmol/L; p = 0.013), homeostasis model assessment of insulin resistance (median 5.4 vs. 3.6; p = 0.025), serum uric acid (404.1 ± 101.2 vs. 322.4 ± 87.1 μmol/L; p = 0.009), and liver fat (median 26.3% vs. 16.3%; p = 0.014).

CONCLUSIONS

Male-predominant hepatic steatosis and insulin resistance caused by sex-specific ectopic fat accumulation may contribute to higher uric acid levels in boys than in girls with NAFLD.

Sex-Related Differences in Cardiovascular Risk in Adolescents with Overweight or Obesity

Background

Pediatric obesity is closely associated with cardiometabolic comorbidities, but the role of sex in this relationship is less investigated. We aimed to evaluate sex-related differences on cardiometabolic risk factors and preclinical signs of target organ damage in adolescents with overweight/obesity (OW/OB).

Methods

The main cross-sectional study included 988 adolescents (510 boys and 478 girls) with OW/OB aged 10-18 years. In all youths clinical and biochemical variables were evaluated and an abdominal echography was performed. Echocardiographic data for the assessment of left ventricular mass (LVM) and relative wall thickness (RWT) were available in an independent sample of 142 youths (67 boys and 75 girls), while echographic data of carotid intima media thickness (cIMT) were available in 107 youths (59 boys and 48 girls).

Results

The three samples did not differ for age, body mass index, and sex distribution. In the main sample, boys showed higher waist-to-height ratio (WHtR) values (p < 0.0001) and fasting glucose levels (p = 0.002) than girls. Lower levels of estimates glomerular filtration rate (eGFR) were found in girls vs boys (p < 0.0001). No sex-related differences for prediabetes and hyperlipidemia were observed. A higher prevalence of WHtR ≥ 0.60 (57.3% vs 49.6%, p = 0.016) and fatty liver disease (FLD) (54.5% vs 38.3%, p < 0.0001) as well as a trend for high prevalence of hypertension (40.4 vs 34.7%, p = 0.06) were observed in boys vs girls. More, a higher prevalence of mild reduced eGFR (MReGFR) ( < 90 mL/min/1.73 m 2 ) was observed in girls vs boys (14.6% vs 9.6 %, p < 0.0001). In the sample with echocardiographic evaluation, boys showed higher levels of LVM (p = 0.046), and RWT (p = 0.003) than girls. Again, in the sample with carotid echography, boys showed higher levels of cIMT as compared to girls (p = 0.011).

Conclusions

Adolescent boys with OW/OB showed higher risk of abdominal adiposity, FLD, and increased cardiac and vascular impairment than girls, whereas the latter had a higher risk of MReGFR. Risk stratification by sex for cardiometabolic risk factors or preclinical signs of target organ damage should be considered in youths with OW/OB.

Thyroid function, adipokines and mitokines in metabolic dysfunction-associated steatohepatitis: A multi-centre biopsy-based observational study

BACKGROUND AND AIMS

Thyroid axis is currently under investigation as a therapeutic target in metabolic dysfunction-associated steatotic liver disease (MASLD). Thyroid function was examined herein in the full spectrum of disease.

METHODS

Subjects were recruited and had liver biopsies in two Gastroenterology-Hepatology Clinics (Greece and Australia) and one Bariatric-Metabolic Surgery Clinic (Italy). The main working sample was n = 677 subjects with MASLD after excluding subjects with abnormal free thyroxine levels. Participants were classified according to thyroid-stimulating hormone (TSH) standard criteria: Subclinical hyperthyroidism (<0.4 uIU/mL); Euthyroidism with relatively low (0.4 to <2.5 uIU/mL); euthyroidism with relatively high (2.5-4.0 uIU/mL); subclinical hypothyroidism (>4 uIU/mL).

RESULTS

TSH as a continuous variable was positively associated with significant fibrosis (F ≥ 2), metabolic dysfunction-associated steatohepatitis (MASH) and at-risk MASH. Subclinical hypothyroidism was associated with fibrosis F ≥ 2 (odds ratio [OR] = 3.47, 95% confident interval [CI] [1.50, 8.05], p = .02), MASH (OR = 3.44, 95% CI [1.48, 7.98] p = .001) and at-risk MASH (OR = 3.88, 95% CI [1.76, 8.55], p = .001), before and after controlling for adiposity, central obesity, and insulin resistance. When leptin, adiponectin, or growth differentiation factor-15 were examined as moderators, significance was lost. Sex-specific analysis revealed a strong association between TSH and the presence of significant fibrosis among women, eliminated only when adipokines/mitokines were adjusted for. Restricted cubic spline analysis revealed associations between TSH and liver outcomes (p-values < .01) with inflection points for fibrosis F ≥ 2 being 2.49, for MASH being 2.67 and for at-risk MASH being 6.96.

CONCLUSIONS

These observations provide support for studies on the administration of thyroid hormone in MASLD therapeutics for subclinical hypothyroidism and liver-specific thyroid receptor agonists for subjects across the TSH continuum.

Sex-Specific Association between Sodium Intake Estimated by 24-Hour Urinary Sodium Excretion and Nonalcoholic Fatty Liver Disease: The Community-Based Prospective Cohort Study

Evidence for the association between high sodium intake and the onset of nonalcoholic fatty liver disease (NAFLD) is insufficient. This study examined the sex-specific association between sodium intake and the risk of NAFLD. This study included 2582 adults (aged 40-69 years; 1011 males and 1571 females). The total sodium excreted over 24 h was estimated from spot urine specimens using Tanaka's equation. Based on these estimates, participants were categorized into three groups according to their 24-h urinary sodium excretion levels: lowest (T1), middle (T2), and highest (T3). In addition, the participants were divided into non-NAFLD (≤36) and NAFLD (>36) groups based on the hepatic steatosis index. During the follow-up period (14 years), NAFLD was observed in 551 participants. The estimated 24-h urinary sodium excretion levels were positively associated with the incidence of NAFLD in all subjects. Upon sex stratification, females in the T2 and T3 groups exhibited adjusted hazard ratios of 1.35 and 1.51, respectively, compared with the T1 group. However, a significant relationship was not observed in males. High intake of sodium, especially among females, may be an important factor contributing to the development of NAFLD. Individuals with high sodium intake should be appropriately counselled and monitored for the risk of NAFLD.

The sulfur microbial diet and risk of nonalcoholic fatty liver disease: a prospective gene-diet study from the UK Biobank

BACKGROUND

The gut microbiota is closely related to liver diseases. The dietary pattern associated with sulfur-metabolizing bacteria in stool has been found to influence intestinal health.

OBJECTIVE

We aimed to investigate whether consuming the sulfur microbial diet is associated with nonalcoholic fatty liver disease (NAFLD).

METHODS

We included 143,918 participants of European descent from the UK Biobank. Information on serving sizes used per diet component was recorded by an online 24-h dietary assessment tool (Oxford WebQ). The total sulfur microbial diet score was constructed by summing the product of β-coefficients and corresponding serving sizes. NAFLD was ascertained using hospital inpatient and death records. Cox proportional hazard models were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI). Mediation analyses were used to investigate underlying mediators including body mass index, waist circumference, glucose, triglyceride, urate, and C-reactive protein. A polygenic risk score for NAFLD was constructed and stratified to assess whether the association is modified by genetic predisposition.

RESULTS

After a median follow-up of 11.7 y (interquartile range: 11.3-12.5 y), we documented 1540 incident cases of NAFLD. After adjustment for covariates, we observed an overall J-shaped relationship between the sulfur microbial diet and risk of NAFLD. Those in the highest quartile of sulfur microbial diet score had a 46% increased risk of NAFLD [HRQ4vsQ1 (95% CI): 1.46 (1.26, 1.69)]. We also found that this association is partly mediated by metabolic disorders and systemic inflammation. In addition, the positive association was stronger among individuals at higher genetic risk for NAFLD (Pinteraction = 0.044).

CONCLUSIONS

The sulfur microbial diet had adverse associations with incident NAFLD, particularly in those at a higher genetic risk. Our study may provide evidence on the role of sulfur-metabolizing bacteria in the diet-NAFLD association.

Circulating microRNA expression and nonalcoholic fatty liver disease in adolescents with severe obesity

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases in children and adolescents. NAFLD ranges in severity from isolated hepatic steatosis to nonalcoholic steatohepatitis (NASH), wherein hepatocellular inflammation and/or fibrosis coexist with steatosis. Circulating microRNA (miRNA) levels have been suggested to be altered in NAFLD, but the extent to which miRNA are related to NAFLD features remains unknown. This analysis tested the hypothesis that plasma miRNAs are significantly associated with histological features of NAFLD in adolescents.

AIM

To investigate the relationship between plasma miRNA expression and NAFLD features among adolescents with NAFLD.

METHODS

This study included 81 adolescents diagnosed with NAFLD and 54 adolescents without NAFLD from the Teen-Longitudinal Assessment of Bariatric Surgery study. Intra-operative core liver biopsies were collected from participants and used to characterize histological features of NAFLD. Plasma samples were collected during surgery for miRNA profiling. A total of 843 plasma miRNAs were profiled using the HTG EdgeSeq platform. We examined associations of plasma miRNAs and NAFLD features using logistic regression after adjusting for age, sex, race, and other key covariates. Ingenuity Pathways Analysis was used to identify biological functions of miRNAs that were associated with multiple histological features of NAFLD.

RESULTS

We identified 16 upregulated plasma miRNAs, including miR-193a-5p and miR-193b-5p, and 22 downregulated plasma miRNAs, including miR-1282 and miR-6734-5p, in adolescents with NAFLD. Moreover, 52, 16, 15, and 9 plasma miRNAs were associated with NASH, fibrosis, ballooning degeneration, and lobular inflammation, respectively. Collectively, 16 miRNAs were associated with two or more histological features of NAFLD. Among those miRNAs, miR-411-5p was downregulated in NASH, ballooning, and fibrosis, while miR-122-5p, miR-1343-5p, miR-193a-5p, miR-193b-5p, and miR-7845-5p were consistently and positively associated with all histological features of NAFLD. Pathway analysis revealed that most common pathways of miRNAs associated with multiple NAFLD features have been associated with tumor progression, while we also identified linkages between miR-122-5p and hepatitis C virus and between miR-199b-5p and chronic hepatitis B.

CONCLUSION

Plasma miRNAs were associated with NAFLD features in adolescent with severe obesity. Larger studies with more heterogeneous NAFLD phenotypes are needed to evaluate miRNAs as potential biomarkers of NAFLD.

Endpoints in NASH Clinical Trials: Are We Blind in One Eye?

This narrative review aims to illustrate the notion that nonalcoholic steatohepatitis (NASH), recently renamed metabolic dysfunction-associated steatohepatitis (MASH), is a systemic metabolic disorder featuring both adverse hepatic and extrahepatic outcomes. In recent years, several NASH trials have failed to identify effective pharmacological treatments and, therefore, lifestyle changes are the cornerstone of therapy for NASH. with this context, we analyze the epidemiological burden of NASH and the possible pathogenetic factors involved. These include genetic factors, insulin resistance, lipotoxicity, immuno-thrombosis, oxidative stress, reprogramming of hepatic metabolism, and hypoxia, all of which eventually culminate in low-grade chronic inflammation and increased risk of fibrosis progression. The possible explanations underlying the failure of NASH trials are also accurately examined. We conclude that the high heterogeneity of NASH, resulting from variable genetic backgrounds, exposure, and responses to different metabolic stresses, susceptibility to hepatocyte lipotoxicity, and differences in repair-response, calls for personalized medicine approaches involving research on noninvasive biomarkers. Future NASH trials should aim at achieving a complete assessment of systemic determinants, modifiers, and correlates of NASH, thus adopting a more holistic and unbiased approach, notably including cardiovascular-kidney-metabolic outcomes, without restricting therapeutic perspectives to histological surrogates of liver-related outcomes alone.

Combining diabetes, sex, and menopause as meaningful clinical features associated with NASH and liver fibrosis in individuals with class II and III obesity: A retrospective cohort study

OBJECTIVE

Steatotic liver disease (SLD) is frequent in individuals with obesity. In this study, type 2 diabetes (T2D), sex, and menopausal status were combined to refine the stratification of obesity regarding the risk of advanced SLD and gain further insight into disease physiopathology.

METHODS

This study enrolled 1446 participants with obesity from the ABOS cohort (NCT01129297), who underwent extensive phenotyping, including liver histology and transcriptome profiling. Hierarchical clustering was applied to classify participants. The prevalence of metabolic disorders associated with steatohepatitis (NASH) and liver fibrosis (F ≥ 2) was determined within each identified subgroup and aligned to clinical and biological characteristics.

RESULTS

The prevalence of NASH and F ≥ 2 was, respectively, 9.5% (N = 138/1446) and 11.7% (N = 159/1365) in the overall population, 20.3% (N = 107/726) and 21.1% (N = 106/502) in T2D patients, and 3.4% (N = 31/920) and 6.1% (N = 53/863) in non-T2D patients. NASH and F ≥ 2 prevalence was 15.4% (33/215) and 15.5% (32/206) among premenopausal women with T2D vs. 29.5% (33/112) and 30.3% (N = 36/119) in postmenopausal women with T2D (p < 0.01); and 21.0% (21/100) / 27.0% (24/89) in men with T2D ≥ age 50 years and 17.9% (17/95) / 18.5% (17/92) in men with T2D < age 50 years (NS). The distinct contribution of menopause was confirmed by the interaction between sex and age with respect to NASH among T2D patients (p = 0.048). Finally, several NASH-associated biological traits (lower platelet count; higher serum uric acid; gamma-glutamyl transferase; aspartate aminotransferase) and liver expressed genes AKR1B10 and CCL20 were significantly associated with menopause in women with T2D but not with age in men with T2D.

CONCLUSIONS

This study unveiled a remarkably high prevalence of advanced SLD after menopause in women with T2D, associated with a dysfunctional biological liver profile.

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 without overlapping metabolic-associated fatty liver disease and the risk of incident type 2 diabetes

BACKGROUND AND AIMS

Re-classifying NAFLD as metabolic-associated fatty liver (MAFLD) has been proposed. While some people fulfil criteria for NAFLD, they do not have MAFLD; and whether NAFLD-only subjects have increased the risk of type 2 diabetes remains unknown. We compared risk of incident T2D in individuals with: (a) NAFLD-only; and (b) MAFLD, to individuals without fatty liver, considering effect modification by sex.

METHODS

246 424 Koreans without diabetes or a secondary cause of ultrasound-diagnosed hepatic steatosis were studied. Subjects were stratified into: (a) NAFLD-only status and (b) NAFLD that overlapped with MAFLD (MAFLD). Cox proportional hazards models with incident T2D as the outcome were used to estimate hazard ratios (HRs) for: (a) and (b). Models were adjusted for time-dependent covariates, and effect modification by sex was analysed in subgroups.

RESULTS

A total of 5439 participants had NAFLD-only status and 56 839 met MAFLD criteria. During a median follow-up of 5.5 years, 8402 incident cases of T2D occurred. Multivariable-adjusted HRs (95% CI) for incident T2D comparing NAFLD-only and MAFLD to the reference (neither condition) were 2.39 (1.63-3.51) and 5.75 (5.17-6.36) (women), and 1.53 (1.25-1.88) and 2.60 (2.44-2.76) (men), respectively. The increased risk of T2D in the NAFLD-only group was higher in women than in men (p for interaction by sex <0.001) and consistently observed across all subgroups. Risk of T2D was increased in lean participants regardless of metabolic dysregulation (including prediabetes).

CONCLUSIONS

NAFLD-only participants without metabolic dysregulation and the criteria for MAFLD are at increased risk of developing T2D. This association was consistently stronger in women than in men.

Association of sex hormones and sex hormone-binding globulin with liver fat in men and women: an observational and Mendelian randomization study

Background

Sex hormones and sex hormone-binding globulin (SHBG) may play a role in fatty liver development. We sought to examine the association of various endogenous sex hormones, including testosterone (T), and SHBG with liver fat using complementary observational and Mendelian randomization (MR) analyses.

Methods

The observational analysis included a total of 2,239 participants (mean age 60 years; 35% postmenopausal women) from the population-based KORA study (average follow-up time: 6.5 years). We conducted linear regression analysis to investigate the sex-specific associations of sex hormones and SHBG with liver fat, estimated by fatty liver index (FLI). For MR analyses, we selected genetic variants associated with sex hormones and SHBG and extracted their associations with magnetic resonance imaging measured liver fat from the largest up to date European genome-wide associations studies.

Results

In the observational analysis, T, dihydrotestosterone (DHT), progesterone and 17α-hydroxyprogesterone (17-OHP) were inversely associated with FLI in men, with beta estimates ranging from -4.23 to -2.30 [p-value <0.001 to 0.003]. Whereas in women, a positive association of free T with FLI (β = 4.17, 95%CI: 1.35, 6.98) was observed. SHBG was inversely associated with FLI across sexes [men: -3.45 (-5.13, -1.78); women: -9.23 (-12.19, -6.28)]. No causal association was found between genetically determined sex hormones and liver fat, but higher genetically determined SHBG was associated with lower liver fat in women (β = -0.36, 95% CI: -0.61, -0.12).

Conclusion

Our results provide suggestive evidence for a causal association between SHBG and liver fat in women, implicating the protective role of SHBG against liver fat accumulation.

Plasma IGFBP-2 levels reveal heterogeneity in hepatic fat content in adults with excess visceral adiposity

Lay summary

Obesity is frequently accompanied by a fatty liver. However, some individuals with high abdominal fat levels nevertheless have low levels of liver fat. Reasons for such discordant phenotypes are unclear. In this paper, we report that among asymptomatic individuals with high levels of visceral fat, low concentrations of IGFBP-2 in the circulation were associated with significantly higher hepatic fat content compared to those with high IGFBP-2 levels. We conclude that quantification of plasma IGFBP-2 concentrations may be useful to identify the early risk for liver fat accumulation in apparently healthy individuals without cardiovascular symptoms.

Aim/hypothesis

Although excess visceral adiposity (VAT) is generally associated with increased liver fat (LF), recent evidence has revealed heterogeneity in LF content among adults with visceral obesity, potentially contributing to specific differences in cardiometabolic outcomes. Reasons for such discordant VAT-LF phenotypes are largely unknown. The present study aimed at assessing whether circulating levels of insulin growth-factor binding protein-2 (IGFBP-2) could be a useful biomarker in the identification of heterogenous and discordant VAT-LF phenotypes.

Methods

A sample of 308 middle-aged Caucasian apparently healthy men and women without cardiovascular symptoms were studied for the present cross-sectional analyses. Fasting plasma glucose and lipid levels were assessed and an oral glucose tolerance test was performed. Hepatic fat fraction (HFF) was measured using magnetic resonance spectroscopy whereas VAT was assessed by magnetic resonance imaging. Plasma IGFBP-2 levels were quantified by ELISA. Participants were then classified on the basis of median VAT (81 mL) and IGFBP-2 levels (233 ng/mL).

Results

Individuals with high levels of VAT were characterized by higher waist circumference, lower insulin sensitivity, as well as by higher plasma triglyceride and lower HDL-cholesterol levels. Plasma IGFBP-2 levels were inversely correlated with HFF (r = -0.39, p < 0.0001). Among men and women with high levels of VAT, those with low levels of IGFBP-2 had significantly higher HFF (7.5 ± 0.7%), compared to participants with high IGFBP-2 concentrations (3.2 ± 0.5%, p < 0.0001).

Conclusion

In the presence of excess VAT, high IGFBP-2 concentrations are associated with low levels of LF. Although additional studies will be necessary to establish causality and further clarify the clinical implications of these observations, these findings are concordant with a novel function of IGFBP-2 in modulating susceptibility to non-alcoholic fatty liver disease (NAFLD) in the presence of visceral obesity.

Serum metabolomic profiling unveils distinct sex-related metabolic patterns in NAFLD

Objective

Obesity poses an increased risk for the onset of Nonalcoholic fatty liver disease (NAFLD). The influence of other factors, such as sex in the incidence and severity of this liver disease has not yet been fully elucidated. Thus, we aimed to identify the NAFLD serum metabolic signatures associated with sex in normal, overweight and obese patients and to associate the metabolite fluctuations across the increasing liver steatosis stages.

Methods and results

Using nuclear magnetic resonance (NMR) serum samples of 210 NAFLD cases and control individuals diagnosed with liver U/S, our untargeted metabolomics enquiry provided a sex distinct metabolic bouquet. Increased levels of alanine, histidine and tyrosine are associated with severity of NAFLD in both men and women. Moreover, higher serum concentrations of valine, aspartic acid and mannose were positively associated with the progression of NAFLD among the male subjects, while a negative association was observed with the levels of creatine, phosphorylcholine and acetic acid. On the other hand, glucose was positively associated with the progression of NAFLD among the female subjects, while levels of threonine were negatively related. Fluctuations in ketone bodies acetoacetate and acetone were also observed among the female subjects probing a significant reduction in the circulatory levels of the former in NAFLD cases. A complex glycine response to hepatic steatosis of the female subjects deserves further investigation.

Conclusion

Results of this study aspire to address the paucity of data on sex differences regarding NAFLD pathogenesis. Targeted circulatory metabolome measurements could be used as diagnostic markers for the distinct stages of NAFLD in each sex and eventually aid in the development of novel sex-related therapeutic options.

Gender Differences in Insulin Resistance: New Knowledge and Perspectives

Insulin resistance is the main mechanism in a whole series of pathological conditions, which are not only of metabolic interest but also of a systemic type. This phenomenon means that the body's cells become less sensitive to the hormone insulin, leading to higher levels of insulin in the blood. Insulin resistance is a phenomenon that can be found in both men and women and in particular, in the latter, it is found mainly after menopause. Premenopause, hormonal fluctuations during the menstrual cycle, and the presence of estrogen can affect insulin sensitivity. Androgens, such as testosterone, are typically higher in men and can contribute to insulin resistance. In both sexes, different human body types affect the distribution and location of body fat, also influencing the development of diabetes and cardiovascular disease. Insulin resistance is also associated with some neurological and neurogenerative disorders, polycystic ovary syndrome, atherosclerosis, and some of the main neoplastic pathologies. A healthy lifestyle, including regular physical activity, a balanced diet, and self-maintenance, can help to prevent the onset of insulin resistance, regardless of gender, although the different habits between men and women greatly affect the implementation of preventative guidelines that help in fighting the manifestations of this metabolic disorder. This review may help to shed light on gender differences in metabolic diseases by placing a necessary focus on personalized medical management and by inspiring differentiated therapeutic approaches.

Associations of MAFLD and MAFLD subtypes with the risk of the incident myocardial infarction and stroke

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a condition characterized by liver fat accumulation and metabolic abnormalities. Given the potential impact of MAFLD on patient health, it is important to understand its association with major adverse cardiovascular events (MACE) such as myocardial infarction (MI) and stroke. In the prospective UK Biobank cohort, we sought to elucidate the association of MAFLD and its subtypes with incident MI and stroke. In this study, we analyzed the data of 325,129 participants in the UK Biobank and calculated relative risks for MI and stroke using Cox regression analysis. Among 325,129 participants over a median duration of 12.8 years follow-up, participants with MAFLD were significantly more likely to experience a MI (hazard ratio [HR] = 1.35, 95% confidence interval [CI: 1.29;1.41] P < 0.001) or a stroke (HR = 1.26 [1.18-1.33] P < 0.001) compared to those without MAFLD. In addition, diabetic, overweight with metabolic dysfunction (MD), and lean MAFLD subtypes were significantly associated with an increased risk for MI and stroke, whereas overweight without MD subtype did not appear to be associated with this risk. Our findings also revealed graded associations between liver fibrosis scores and risk of MI and stroke in MAFLD patients. However, only diabetic, and overweight patients with MD subtypes exhibited graded associations between liver fibrosis score and the risk of MI and stroke among the MAFLD subtypes. Furthermore, the risk alleles traits of fatty liver did not enhance the effect of MAFLD on the risk of MI and stroke. In conclusion, a diagnosis of MAFLD is associated with an increased risk of MI or stroke, and the assessment of MAFLD and its subtypes should be a component of the cardiovascular risk assessment.

Nonalcoholic liver disease: Epidemiology, risk factors, natural history, and management strategies

Nonalcoholic fatty liver disease (NAFLD) is now the most common chronic liver disease worldwide and a leading indication for liver transplantation in the United States. NAFLD encompasses a heterogeneous clinicopathologic spectrum, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis, and progressive fibrosis, which can lead to end-stage liver disease including cirrhosis and hepatocellular cancer. Predictive models suggest that over 100 million adults in the United States will have NAFLD by 2030, representing over a third of the population. In this manuscript, we provide an overview of NAFLD risk factors, natural history (including hepatic and extra-hepatic outcomes), diagnosis, and current management strategies.

The heterogeneity of metabolic syndrome presentation and challenges this causes in its pharmacological management: a narrative review focusing on principal risk modifiers

INTRODUCTION

Metabolic syndrome (MetS), i.e. the cluster of cardiometabolic risk factors comprising visceral obesity, impaired glucose metabolism, arterial hypertension and atherogenic dyslipidemia, is prevalent globally and exacts a heavy toll on health care expenditures.

AREAS COVERED

The pathophenotypes of individual traits of the MetS in adults are discussed first, with strong emphasis on nonalcoholic fatty liver disease (NAFLD) and sex differences. Next, I discuss recent studies on phenotypic and outcome heterogeneity of the MetS, highlighting the role of NAFLD, sex, reproductive status, and depressive disorders. In the second half of the article, the therapeutic implications of the variable MetS types and features are analyzed, focusing on the most recent developments, and guidelines.

EXPERT OPINION

I have identified physiological, pathological, social and medical sources of phenotypical heterogeneity in the MetS and its constitutive traits. Improved understanding of these variables may be utilized in the setting of future precision medicine approaches in the field of metabolic disorders and target organ damage.

Association between fatty liver index and risk of end-stage renal disease stratified by kidney function in patients with type 2 diabetes: A nationwide population-based study

OBJECTIVE

The effects of nonalcoholic fatty liver disease on the risk of end-stage renal disease (ESRD) remain unclear. We investigated the association between the fatty liver index (FLI) and risk of ESRD in patients with type 2 diabetes.

METHODS

This population-based observational cohort study enrolled patients with diabetes who underwent health screening between 2009 and 2012 and utilized data from the Korean National Health Insurance Services. The FLI functioned as a surrogate marker for the presence of hepatic steatosis. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate < 60 ml/min/1.73 m² calculated using the Modification of Diet in Renal Disease equation. We performed Cox proportional hazards regression.

RESULTS

Incident ESRD developed in 19,476 of 1,900,598 patients with type 2 diabetes during a median follow-up of 7.2 years. After adjusting for conventional risk factors, patients with high FLI scores had a higher risk for ESRD: FLI, 30-59 [hazard ratio (HR) = 1.124; 95% confidence interval (CI), 1.083-1.166]; FLI ≥ 60 [HR = 1.278; 95% CI, 1.217-1.343] compared with those with FLI < 30. The association between a high FLI score (≥ 60) and incident ESRD was more prominent in women than in men (male, FLI ≥60: HR, 1.106; 95% CI = 1.041-1.176 and female, FLI ≥ 60: HR, 1.835; 95% CI = 1.689-1.995). The association between a high FLI score (≥ 60) and the risk of ESRD differed according to baseline kidney function. High FLI scores increased the risk of ESRD (HR = 1.268; 95% CI, 1.198-1.342) in patients with CKD at baseline.

CONCLUSION

High FLI scores are associated with a greater risk of ESRD in patients with type 2 diabetes with CKD at baseline. Close monitoring and appropriate management of hepatic steatosis may aid in preventing the progression of kidney dysfunction in patients with type 2 diabetes and CKD.

Interaction between increasing body mass index and spinal cord injury to the probability of developing a diagnosis of nonalcoholic fatty liver disease

Background

The prevalence of obesity and comorbidities is high in the population with spinal cord injury (SCI). We sought to determine the effect of SCI on the functional form of the relationship between body mass index (BMI) and risk of developing nonalcoholic fatty liver disease (NAFLD), and assess whether SCI-specific mapping of BMI to risk of developing NAFLD is needed.

Methods

Longitudinal cohort study comparing Veterans Health Administration patients with a diagnosis of SCI to a 1:2 matched control group without SCI. The relationship between BMI and development of NAFLD at any time was assessed with propensity score matched Cox regression models; NAFLD development at 10-year with a propensity score matched logistic model. The positive predictive value of developing NAFLD at 10 years was calculated for BMI 19-45 kg/m2.

Results

14,890 individuals with SCI met study inclusion criteria, and 29,780 Non-SCI individuals in matched control group. Overall, 9.2% in SCI group and 7.3% in Non-SCI group developed NAFLD during the study period. A logistic model assessing the relationship between BMI and the probability of developing a diagnosis of NAFLD demonstrated that the probability of developing disease increased as BMI increased in both cohorts. The probability was significantly higher in the SCI cohort at each BMI threshold (p < 0.01), and increased at a higher rate compared with the Non-SCI cohort as BMI increased 19-45 kg/m2. Positive predictive value for developing a diagnosis of NAFLD was higher in the SCI group for any given BMI threshold from 19 kg/m2 to BMI 45 kg/m2.

Conclusions

The probability of developing NAFLD is greater in individuals with SCI than without SCI, at every BMI level 19 kg/m2 to 45 kg/m2. Individuals with SCI may warrant a higher level of suspicion and closer screening for NAFLD. The association of SCI and BMI is not linear.

MAFLD is associated with increased all-cause mortality in low cardiovascular-risk individuals but not in intermediate to high-risk individuals

BACKGROUND AND AIMS

Metabolic-associated fatty liver disease (MAFLD) is increasingly recognized as a systematic disease rather than just a liver disease alone, which raises concerns about its long-term impact on different populations. This study aimed to clarify the effects of MAFLD on long-term outcomes among different cardiovascular risk-stratified populations.

METHODS AND RESULTS

Eligible individuals in the Third National Health and Nutrition Examination Surveys (NHANES Ⅲ, 1988-1994) were enrolled. Participants were classified into low, intermediate, or high cardiovascular-risk populations according to the Framingham general equations. Kaplan-Meier survival analysis and Cox regression models were used to investigate the association between MAFLD and long-term outcomes in different cardiovascular-risk populations. A total of 8897 adults were enrolled in the final analysis. The median ages in the non-MAFLD and MAFLD groups were 44 and 49 years old, respectively. During a median follow-up of 22.8 years, a total of 2991 deaths were recorded, including 1694 deaths (30.3%) in non-MAFLD and 1297 deaths (39.2%) in MAFLD (P < 0.001). In the low cardiovascular-risk population, MAFLD individuals had increased all-cause mortality than non-MAFLD individuals (HR = 1.206, 95% CI:1.0338-1.400, P = 0.014). However, similar results were not observed in intermediate or high-cardiovascular-risk individuals. Further analysis of cause-specific mortality suggested that MAFLD was associated with higher cancer-related mortality in the low-risk population (HR = 1.313, 95% CI:1.000-1.725, P = 0.049).

CONCLUSIONS

MAFLD was associated with increased all-cause mortality among individuals with low cardiovascular risk, rather than those with an intermediate or high cardiovascular risk.

Association of Healthy Lifestyles with Non-Alcoholic Fatty Liver Disease: A Prospective Cohort Study in Chinese Government Employees

BACKGROUND

Evidence indicates that certain healthy lifestyle factors are associated with non-alcoholic fatty liver disease (NAFLD). However, little is known about the effect of combined healthy lifestyle factors.

OBJECTIVE

To assess the association of combined healthy lifestyle factors with the incidence of NAFLD.

METHODS

This cohort study was conducted in Changsha, Hunan Province, China. The healthy lifestyles factors studied were not being a current smoker, having a healthy diet, engaging in physical activity, having a normal body mass index (BMI) and engaging in non-sedentary behavior. NAFLD was diagnosed based on abdominal ultrasonography. Logistic regression models were conducted to investigate the associations being studied.

RESULTS

Of the 5411 participants, 1280 participants had NAFLD, with a prevalence of 23.7% at baseline. The incidence of NAFLD among participants without NAFLD at baseline was found to be 7.2% over a mean follow-up of 1.1 years. Compared with participants with 0-1 low-risk factors, the OR of NAFLD was 0.50 (95% CI: 0.29-0.82, p = 0.008) for those with at least 4 low-risk factors. Similar associations were observed in subgroup analyses and sensitivity analyses.

CONCLUSION

This study suggests that a combined healthy lifestyle pattern may considerably decrease the risk of NAFLD in Chinese government employees.

Mouse Models for Hepatic Stellate Cell Activation and Liver Fibrosis Initiation

Liver fibrosis is a severe health problem worldwide with increasing incidence. However, specific drugs for treatment of hepatic fibrosis are currently not available. Accordingly, there is a strong need to conduct intensive basic research, which also includes the necessity to use animal models to evaluate new anti-fibrotic therapy concepts. Numerous mouse models of liver fibrogenesis have been described. This involves chemical, nutritional, surgical, and genetic mouse models, which involve also activation of hepatic stellate cells (HSCs). However, for many investigators, it may be challenging to identify the most suitable model for a specific question on liver fibrosis research. In this chapter, we will provide a brief overview about the most common mouse models of HSC activation and liver fibrogenesis and thereafter provide detailed step-by-step protocols of two selected mouse fibrosis models based on own experience, which in our opinion are best suited to cover many current scientific issues. On the one hand, there is the classical carbon tetrachloride (CCl₄) model; this model of toxic liver fibrogenesis is still one of the best suited and most reproducible models for basic features of hepatic fibrogenesis. On the other hand, we also introduce the novel DUAL model of alcohol plus metabolic/alcoholic fatty liver disease developed in our laboratory, which mimics all histological, metabolic, and transcriptomic gene signatures of human advanced steatohepatitis and related liver fibrosis. We describe all the information required for proper preparation and detailed implementation of both models including animal welfare aspects, thereby serving as a useful laboratory guide for mouse experimentation in liver fibrosis research.

Heart Uptake of [18F]Fluoro-4-Thia-Oleate in a Non-Alcoholic Fatty Liver Disease Mouse Model

The world-wide high incidence of non-alcoholic fatty liver disease (NAFLD) is of concern for its progression to insulin resistance, steatohepatitis and cardiovascular disease (CVD). The increased uptake of fatty acids in critical organs plays a major role in NAFLD progression. Male Ceacam1−/− mice that develop NAFLD, insulin resistance and CVD on normal chow are a potential model for studying the dysregulation of fatty acid uptake. [18F]fluoro-4-thia-oleate ([18F]FTO) was chosen as a fatty acid reporter because of its higher uptake and retention in the heart in an animal model of CVD. Male wild-type (WT) or Ceacam1−/− mice fasted 4−6 h were administered [18F]FTO i.v., and dynamic PET scans were conducted in an MR/PET small animal imaging system along with terminal tissue biodistributions. Quantitative heart image analysis revealed significantly higher uptake at 35 min in Ceacam1−/− (6.0 ± 1.0% ID/cc) vs. WT (3.9 ± 0.6% ID/cc) mice (p = 0.006). Ex vivo heart uptake/retention (% ID/organ) was 2.82 ± 0.45 for Ceacam1−/− mice vs. 1.66 ± 0.45 for WT mice (p < 0.01). Higher kidney and pancreas uptake/retention in Ceacam1−/− was also evident, and the excretion of [18F]FTO into the duodenum was observed for both WT and Ceacam1−/− mice starting at 10 min. This study suggests that the administration of [18F]FTO as a marker of fatty acid uptake and retention may be an important tool in analyzing the effect of NAFLD on lipid dysregulation in the heart.

NAFLD improves risk prediction of type 2 diabetes: with effect modification by sex and menopausal status

BACKGROUND AND AIMS

The effects of sex and menopausal status on the association between NAFLD and incident type 2 diabetes (T2D) remain unclear. We investigated the effect modification by sex and menopause in the association between NAFLD and T2D; also, the added predictive ability of NAFLD for the risk of T2D was assessed.

APPROACH AND RESULTS

This cohort study comprised 245,054 adults without diabetes (109,810 premenopausal women; 4958 postmenopausal women; 130,286 men). Cox proportional hazard models were used to estimate hazard ratios (HRs; 95% confidence intervals [CIs]) for incident T2D according to NAFLD status. The incremental predictive role of NAFLD for incident T2D was assessed using the area under the receiver operating characteristic curve, net reclassification improvement, and integrated discrimination improvement. A total of 8381 participants developed T2D (crude incidence rate/10³ person-years: 2.9 premenopausal women; 12.2 postmenopausal women; 9.3 men) during median follow-up of 5.3 years. NAFLD was positively associated with incident T2D in all groups. After adjustment for potential confounders, the multivariable-adjusted HRs (95% CIs) for incident T2D comparing NAFLD to no NAFLD were 4.63 (4.17-5.14), 2.65 (2.02-3.48), and 2.16 (2.04-2.29) in premenopausal women, postmenopausal women, and men, respectively. The risks of T2D increased with NAFLD severity as assessed by serum fibrosis markers, and the highest relative excess risks were observed in premenopausal women. The addition of NAFLD to conventional risk factors improved risk prediction for incident T2D in both sexes, with a greater improvement in women than men.

CONCLUSIONS

NAFLD, including more severe NAFLD, is a stronger risk factor for incident T2D in premenopausal women than in postmenopausal women or men; protection against T2D is lost in premenopausal women with NAFLD.

Association between metabolically healthy obesity and non-alcoholic fatty liver disease

BACKGROUND

The risks of NAFLD and NAFLD with fibrosis progression among metabolically healthy obesity (MHO) individuals are largely unexplored. This cohort study investigated the association between MHO as well as other metabolic syndrome-obesity combined phenotypes and NAFLD and its fibrosis progression.

METHODS

Participants included 31,010 adults from a health check-up cohort free from NAFLD and intermediate or high probability of advanced fibrosis at baseline. Metabolically healthy was defined as not having any component of metabolic syndrome. Obesity was identified by body mass index (BMI) and waist circumference (WC). Participants were cross-classified by metabolic health and obesity at baseline. The outcomes were NAFLD, and NAFLD with fibrosis progression, as assessed by abdominal B-type ultrasound and noninvasive fibrosis score.

RESULTS

During a median follow-up of 2.2 (interquartile range, 1.2-4.9) years, 7,393 participants developed NAFLD. MHO individuals (HR 5.51, 95% CI 4.98, 6.09 for BMI criteria; HR 6.76, 95% CI 6.04, 7.57 for WC criteria) had a significantly higher risk of NAFLD than those with metabolically healthy normal weight or low WC. The corresponding HRs (95% CIs) for metabolically healthy overweight (defined by BMI) and medium WC were 2.74 (2.49-3.02) and 2.93 (2.65-3.24), respectively. Furthermore, 557 participants developed NAFLD with fibrosis progression. The association between different obesity phenotypes and NAFLD with fibrosis progression also showed a similar pattern.

CONCLUSION

MHO was associated with significantly higher risks of NAFLD and its fibrosis progression, suggesting that regarding NAFLD prevention, MHO individuals might still benefit from lifestyle interventions aimed at body weight and WC maintenance.

Gender Dimorphism in Hepatic Carcinogenesis-Related Gene Expression Associated with Obesity as a Low-Grade Chronic Inflammatory Disease

Non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) show clear evidence of sexual dimorphism, with a significantly higher incidence in males. Among the determining factors that could explain this sex-based difference, the specific distribution of fat by sex has been suggested as a primary candidate, since obesity is a relevant risk factor. In this context, obesity, considered a low-grade chronic inflammatory pathology and responsible for the promotion of liver disease, could lead to sexual dimorphism in the expression profile of genes related to tumor development. When we compared the expression levels of genes associated with the early stages of carcinogenesis in the liver between male and female diet-induced obesity (DIO) rats, we observed that the expression pattern was similar in obese male and female animals. Interestingly, the SURVIVIN/BIRC5 oncogene showed a higher expression in male DIO rats than in female DIO and lean rats. This trend related to sexual dimorphism was observed in leukocytes from patients with obesity, although the difference was not statistically significant. In conclusion, this study evidenced a similar pattern in the expression of most carcinogenesis-related genes in the liver, except SUVIVIN/BIRC5, which could be a predictive biomarker of liver carcinogenesis predisposition in male patients with obesity.

Role of Circadian Clock on the Pathogenesis and Lifestyle Management in Non-Alcoholic Fatty Liver Disease

Several features of the modern lifestyle, such as weekly schedules or irregular daily eating patterns, have become major drivers of global health problems, including non-alcoholic fatty liver disease (NAFLD). Sleep is an essential component of human well-being, and it has been observed that when circadian rhythms are disrupted, or when sleep quality decreases, an individual's overall health may worsen. In addition, the discrepancy between the circadian and social clock, due to weekly work/study schedules, is called social jetlag and has also been associated with adverse metabolic profiles. Current management of NAFLD is based on dietary intake and physical activity, with circadian preferences and other environmental factors also needing to be taken into account. In this regard, dietary approaches based on chrononutrition, such as intermittent fasting or time-restricted feeding, have proven to be useful in realigning lifestyle behaviors with circadian biological rhythms. However, more studies are needed to apply these dietary strategies in the treatment of these patients. In this review, we focus on the impact of circadian rhythms and the role of sleep patterns on the pathogenesis and development of NAFLD, as well as the consideration of chrononutrition for the precision nutrition management of patients with NAFLD.

Deciphering the role of aberrant DNA methylation in NAFLD and NASH

The global incidence of nonalcoholic fatty liver disease (NAFLD) is mounting incessantly, and it is emerging as the most frequent cause of chronic and end stage liver disorders. It is the starting point for a range of conditions from simple steatosis to more progressive nonalcoholic steatohepatitis (NASH) and associated hepatocellular carcinoma (HCC). Dysregulation of insulin secretion and dyslipidemia due to obesity and other lifestyle variables are the primary contributors to establishment of NAFLD. Onset and progression of NAFLD is orchestrated by an interplay of metabolic environment with genetic and epigenetic factors. An incompletely understood mechanism of NAFLD progression has greatly hampered the progress in identification of novel prognostic and therapeutic strategies. Emerging evidence suggests altered DNA methylation pattern as a key determinant of NAFLD pathogenesis. Environmental and lifestyle factors can manipulate DNA methylation patterns in a reversible manner, which manifests as changes in gene expression. In this review we attempt to highlight the importance of DNA methylation in establishment and progression of NAFLD. Development of novel diagnostic, prognostic and therapeutic strategies centered around DNA methylation signatures and modifiers has also been explored.

Molecular programming modulates hepatic lipid metabolism and adult metabolic risk in the offspring of obese mothers in a sex-specific manner

Male and female offspring of obese mothers are known to differ extensively in their metabolic adaptation and later development of complications. We investigate the sex-dependent responses in obese offspring mice with maternal obesity, focusing on changes in liver glucose and lipid metabolism. Here we show that maternal obesity prior to and during gestation leads to hepatic steatosis and inflammation in male offspring, while female offspring are protected. Females from obese mothers display important changes in hepatic transcriptional activity and triglycerides profile which may prevent the damaging effects of maternal obesity compared to males. These differences are sustained later in life, resulting in a better metabolic balance in female offspring. In conclusion, sex and maternal obesity drive differently transcriptional and posttranscriptional regulation of major metabolic processes in offspring liver, explaining the sexual dimorphism in obesity-associated metabolic risk.

Sex and maternal obesity drive differently transcriptional and posttranscriptional regulation of major metabolic processes in the livers of female and male offspring, contributing to the sexual dimorphism in obesity-associated metabolic risk.

Sex- and gender-differences in chronic long-term complications of type 1 and type 2 diabetes mellitus in Italy

AIMS

This review summarizes the contribution of Italian diabetologists devoted to a better understanding of the complex relationship linking sex/gender and long-term complications of type 1 (T1DM) and type 2 diabetes (T2DM) over the last fifteen years.

DATA SYNTHESIS

Microvascular and macrovascular complications of diabetes show sex- and gender-related differences, involving pathophysiological mechanisms, epidemiological features and clinical presentation, due to the interaction between biological and psychosocial factors. These differences greatly impact on the progression of diabetes and its long-term complications, especially in the cardiovascular, renal and liver districts.

CONCLUSION

A better knowledge of such sex- and gender-related characteristics is required for a more precise patient phenotypization, and for the choice of a personalized antihyperglycemic treatment. Despite such mounting evidence, current diabetes clinical guidelines do not as yet adequately consider sex/gender differences.

The impact of health status, diet and lifestyle on non-alcoholic fatty liver disease: Narrative review

Non-alcoholic fatty liver disease (NAFLD) is defined as the abnormal accumulation of triglycerides in the liver. NAFLD has a global prevalence of almost 30%, while incidence is rising with increasing levels of obesity, type 2 diabetes mellitus (T2DM) and metabolic syndrome. Nutrition plays a significant role in both the prevention and treatment of NAFLD. Therefore, the aim of this literature review is to explore the associations between dietary, lifestyle and other risk factors and the risk for developing NAFLD. Dietary patterns, lifestyle behaviours, comorbidities, or a combination of any may contribute to either the progression or prevention of NAFLD. Having diabetes, hypertension, or having obesity might increase the progression of NAFLD if not well treated and controlled. Diet influences the progression of NAFLD; following a western diet or simply a high-fat diet may contribute to the worsening of NAFLD and further progression to non-alcoholic steatohepatitis (NASH) and cirrhosis in later stages. On the other hand, the Mediterranean diet is the gold standard for both the treatment and prevention of NAFLD. Social behaviours, such as smoking, caffeine consumption and physical activity also play a role in the pathophysiology of NAFLD. Nutrition contributes significantly to the prevention or treatment of NAFLD, since this disease can be managed by diet and physical activity. However, further studies are still needed for a better understanding of the mechanisms of action. Randomized control trials are also needed to confirm findings in observational studies.

Associations of Sex Steroids and Sex Hormone-Binding Globulin with Non-Alcoholic Fatty Liver Disease: A Population-Based Study and Meta-Analysis

Background: Prior studies have reported inconsistent results or less well-explored associations between sex hormones and non-alcoholic fatty liver disease (NAFLD). Here, we aimed to investigate the associations of NAFLD with sex steroids and sex hormone-binding globulin (SHBG) in the population-based study and conduct a comprehensive systematic review and meta-analysis of all published observational studies. Methods: Analyses included 755 men and 1109 women with available data on sex steroids, SHBG, and ultrasound-based NAFLD from the Rotterdam Study. Multivariable regression models were used to examine the associations. Additionally, we searched five databases from inception to 1 April 2022 and performed a systematic review and meta-analysis. Random-effects (DerSimonian-Laird) method was used for meta-analysis, odds ratios (ORs) were calculated for the effect estimate, subgroup and leave-one-out sensitivity analyses were conducted, and meta-regression was performed to explore the pooled statistics with high heterogeneity. Results: In the Rotterdam Study, lower levels of SHBG were associated with NAFLD in both sexes, while lower testosterone was associated with NAFLD only among women. Similarly, the meta-analysis of 16 studies indicated no sex-specific association between SHBG and NAFLD (men: OR = 0.37, 95%CI 0.21–0.53; women: OR = 0.40, 95%CI 0.21–0.60), yet there was a sex-specific association between testosterone and NAFLD (men: OR = 0.59, 95%CI 0.42–0.76; women: OR = 1.06, 95%CI 0.68–1.44). Moreover, men with NAFLD had lower estradiol levels than those without NAFLD. Conclusions: Lower SHBG levels were associated with NAFLD in both sexes, but testosterone levels were associated in a sex-specific manner. In addition, our results showed estradiol with the potential as a protective factor for NAFLD in healthy men.

PPAR-Targeted Therapies in the Treatment of Non-Alcoholic Fatty Liver Disease in Diabetic Patients

Peroxisome proliferator-activated receptors (PPAR), ligand-activated transcription factors of the nuclear hormone receptor superfamily, have been identified as key metabolic regulators in the liver, skeletal muscle, and adipose tissue, among others. As a leading cause of liver disease worldwide, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) cause a significant burden worldwide and therapeutic strategies are needed. This review provides an overview of the evidence on PPAR-targeted treatment of NAFLD and NASH in individuals with type 2 diabetes mellitus. We considered current evidence from clinical trials and observational studies as well as the impact of treatment on comorbid metabolic conditions such as obesity, dyslipidemia, and cardiovascular disease. Future areas of research, such as possible sexually dimorphic effects of PPAR-targeted therapies, are briefly reviewed.

Nonalcoholic Fatty Liver Disease and Endocrine Axes—A Scoping Review

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD often occurs associated with endocrinopathies. Evidence suggests that endocrine dysfunction may play an important role in NAFLD development, progression, and severity. Our work aimed to explore and summarize the crosstalk between the liver and different endocrine organs, their hormones, and dysfunctions. For instance, our results show that hyperprolactinemia, hypercortisolemia, and polycystic ovary syndrome seem to worsen NAFLD’s pathway. Hypothyroidism and low growth hormone levels also may contribute to NAFLD’s progression, and a bidirectional association between hypercortisolism and hypogonadism and the NAFLD pathway looks likely, given the current evidence. Therefore, we concluded that it appears likely that there is a link between several endocrine disorders and NAFLD other than the typically known type 2 diabetes mellitus and metabolic syndrome (MS). Nevertheless, there is controversial and insufficient evidence in this area of knowledge.

Disruption of the circadian clock component BMAL1 elicits an endocrine adaption impacting on insulin sensitivity and liver disease

SignificanceWhile increasing evidence associates the disruption of circadian rhythms with pathologic conditions, including obesity, type 2 diabetes, and nonalcoholic fatty liver diseases (NAFLD), the involved mechanisms are still poorly described. Here, we show that, in both humans and mice, the pathogenesis of NAFLD is associated with the disruption of the circadian clock combined with perturbations of the growth hormone and sex hormone pathways. However, while this condition protects mice from the development of fibrosis and insulin resistance, it correlates with increased fibrosis in humans. This suggests that the perturbation of the circadian clock and its associated disruption of the growth hormone and sex hormone pathways are critical for the pathogenesis of metabolic and liver diseases.

The advantages of physical exercise as a preventive strategy against NAFLD in postmenopausal women

BACKGROUND

The prevalence and severity of nonalcoholic fatty liver disease (NAFLD) increase in women after menopause. This narrative review discusses the causes and consequences of NAFLD in postmenopausal women and describes how physical activity can contribute to its prevention.

METHODS

The authors followed the narrative review method to perform a critical and objective analysis of the current knowledge on the topic. The Medical Subject Heading keywords 'physical exercise', 'menopause', 'hormone replacement therapy', 'estradiol' and 'NAFLD' were used to establish a conceptual framework. The databases used to collect relevant references included Medline and specialized high-impact journals.

RESULTS

Higher visceral adiposity, higher rate of lipolysis in adipose tissue after oestrogen drop and changes in the expression of housekeeping proteins involved in hepatic lipid management are observed in women after menopause, contributing to NAFLD. Excessive liver steatosis leads to hepatic insulin resistance, oxidative stress and inflammation, accelerating NAFLD progression. Physical activity brings beneficial effects against several postmenopausal-associated complications, including NAFLD progression. Aerobic and resistance exercises partially counteract alterations induced by metabolic syndrome in sedentary postmenopausal women, impacting NAFLD progression and severity.

CONCLUSIONS

With the increased global obesity epidemic in developing countries, NAFLD is becoming a severe problem with increased prevalence in women after menopause. Evidence shows that physical activity may delay NAFLD development and severity in postmenopausal women, although the prescription of age-appropriate physical activity programmes is advisable to assure the health benefits.

Machine learning to predict progression of non-alcoholic fatty liver to non-alcoholic steatohepatitis or fibrosis

Background

Non-alcoholic fatty liver (NAFL) can progress to the severe subtype non-alcoholic steatohepatitis (NASH) and/or fibrosis, which are associated with increased morbidity, mortality, and healthcare costs. Current machine learning studies detect NASH; however, this study is unique in predicting the progression of NAFL patients to NASH or fibrosis.

Aim

To utilize clinical information from NAFL-diagnosed patients to predict the likelihood of progression to NASH or fibrosis.

Methods

Data were collected from electronic health records of patients receiving a first-time NAFL diagnosis. A gradient boosted machine learning algorithm (XGBoost) as well as logistic regression (LR) and multi-layer perceptron (MLP) models were developed. A five-fold cross-validation grid search was utilized for hyperparameter optimization of variables, including maximum tree depth, learning rate, and number of estimators. Predictions of patients likely to progress to NASH or fibrosis within 4 years of initial NAFL diagnosis were made using demographic features, vital signs, and laboratory measurements.

Results

The XGBoost algorithm achieved area under the receiver operating characteristic (AUROC) values of 0.79 for prediction of progression to NASH and 0.87 for fibrosis on both hold-out and external validation test sets. The XGBoost algorithm outperformed the LR and MLP models for both NASH and fibrosis prediction on all metrics.

Conclusion

It is possible to accurately identify newly diagnosed NAFL patients at high risk of progression to NASH or fibrosis. Early identification of these patients may allow for increased clinical monitoring, more aggressive preventative measures to slow the progression of NAFL and fibrosis, and efficient clinical trial enrollment.

Young adults with nonalcoholic fatty liver disease, defined using the fatty liver index, can be at increased risk of myocardial infarction or stroke

AIM

To investigate the relationship between nonalcoholic fatty liver disease (NAFLD) and cardiovascular events among a nationally representative sample of young adults in Korea.

METHODS AND RESULTS

This population-based cohort study from the Korean National Health Insurance Service included adults who were aged 20 to 39 years when they underwent a health examination between 2009 and 2012. NAFLD was defined as a fatty liver index (FLI) ≥60, and participants were divided into three groups according to FLI (<30, 30-59 and ≥60) to investigate the dose-dependent effect of FLI score. Among 5 324 410 participants, 9.8% had an FLI ≥60. There were 13 051 myocardial infarctions (MIs; 0.39%) and 8573 strokes (0.26%) during a median follow-up of 8.4 years. In multivariable analysis, NAFLD was associated with a higher risk of MI and stroke (hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.61-1.77 and HR  1.73, 95% CI 1.63-1.84, respectively). MI and stroke had dose-dependent relationships with FLI (HR 1.28 in participants with FLI 30-59 and 1.73 in those with FLI ≥60 for MI and HR 1.18 in participants with FLI 30-59 and 1.41 in those with FLI ≥60 for stroke, respectively).

CONCLUSIONS

Nonalcholic fatty liver disease was an independent predictor of MI and stroke in young adults. These results suggest that primary prevention of cardiovascular disease should be emphasized in young adults with NAFLD.

Non-alcoholic/Metabolic-Associated Fatty Liver Disease and Helicobacter pylori Additively Increase the Risk of Arterial Stiffness

Background

Non-alcoholic fatty liver disease (NAFLD) and Helicobacter pylori (Hp) infection have a close association with an increased risk of cardiovascular disease. Metabolic dysfunction-associated fatty liver disease (MAFLD) is characterized by metabolic dysfunction in NAFLD. We investigated the synergistic effects of NAFLD/MAFLD and Hp infection on the risk of arterial stiffness in an asymptomatic population.

Methods

We included individuals who underwent abdominal ultrasonography, anti-Hp IgG antibody evaluations and cardio-ankle vascular index (CAVI) during health screening tests between January 2013 and December 2017. Arterial stiffness was defined using CAVI. A logistic regression model was used to analyze the independent and synergistic effects of NAFLD/MAFLD and Hp infection on the risk of arterial stiffness.

Results

Among 3,195 subjects (mean age 54.7 years, 68.5% male), the prevalence of increased arterial stiffness was 36.4%. In the multivariate analysis, subjects with NAFLD but without Hp infection and those with both NAFLD and Hp infection had a significantly higher risk of increased arterial stiffness [odds ratio (OR) 1.61, 95% confidence interval (CI) 1.15–2.26, and OR 2.23, 95% CI 1.63–3.06, respectively], than subjects without Hp infection and NAFLD. Regarding MAFLD, Hp infection additively increased the risk of arterial stiffness in subjects with MAFLD (OR 2.13, 95% CI 1.64–2.78).

Conclusions

An interactive effect of Hp infection on the risk of arterial stiffness in individuals with NAFLD/MAFLD was observed. Hp infection additively increases the risk of arterial stiffness in subjects with NAFLD or MAFLD.

Cell Models and Omics Techniques for the Study of Nonalcoholic Fatty Liver Disease: Focusing on Stem Cell-Derived Cell Models

Nonalcoholic fatty liver disease (NAFLD) is now the leading cause of chronic liver disease in western countries. The molecular mechanisms leading to NAFLD are only partially understood, and effective therapeutic interventions are clearly needed. Therefore, preclinical research is required to improve knowledge about NAFLD physiopathology and to identify new therapeutic targets. Primary human hepatocytes, human hepatic cell lines, and human stem cell-derived hepatocyte-like cells exhibit different hepatic phenotypes and have been widely used for studying NAFLD pathogenesis. In this paper, apart from employing the different in vitro cell models for the in vitro assessment of NAFLD, we also reviewed other approaches (metabolomics, transcriptomics, and high-content screening). We aimed to summarize the characteristics of different cell types and methods and to discuss their major advantages and disadvantages for NAFLD modeling.

Fructose-Rich Diet Attenuates Stress-Induced Metabolic Disturbances in the Liver of Adult Female Rats

BACKGROUND

Both fructose consumption and chronic stress contribute to the development of metabolic disorders. The consequences of such combination are not fully understood.

OBJECTIVE

We investigated whether fructose supplementation and chronic stress synergistically disturb hepatic lipid and glucose metabolism. The role of energy sensing, redox, and inflammatory status during development of metabolic disturbances was investigated.

METHODS

Female Wistar rats, aged 2.5 mo, were divided into 4 experimental groups: control (C) fed a standard diet (commercial food and drinking water); fructose (F) fed the same food and 10% fructose solution; stress (S) fed the standard diet and subjected to chronic unpredictable stress and, stress + fructose (SF) combining conditions F and S as above. Stress included daily stressors: cold water forced swimming, physical restraint, cold room, wet bedding, rocking, switching, or tilting cages. After 9 wk, hepatic enzymes and transcription factors involved in gluconeogenesis, lipogenesis, fatty acid oxidation, antioxidative defence, energy sensing, and cytokines were assessed by qPCR, Western blotting, and spectrophotometry and analyzed by 2-factor ANOVA.

RESULTS

Fructose increased AMP-activated protein kinase (AMPK) phosphorylation (40%; P < 0.05) and the ratio of inhibitory phosphorylation to total acetyl-CoA carboxylase (46%; P < 0.01), and decreased sterol regulatory element binding protein 1c nuclear translocation by 30% (P < 0.05) in F and SF compared with C rats. Increased phosPck (phoenolpyruvate carboxykinase) (85%) and G6pase(glucose-6-phosphatase) (55%) was observed in S rats (P < 0.05). A 40% decrease in Apob (apolipoprotein B-100) and an increase in hepatic lipids (P < 0.05), together with a double increase in TNF-α (P < 0.001), were observed in S rats, but without liver histopathological changes. These stress effects on lipid accumulation and TNF-α were abolished in SF rats (P < 0.05).

CONCLUSIONS

Fructose does not enhance stress effects on hepatic lipid and glucose metabolism but attenuates its effects on hepatic lipid accumulation and inflammation, suggesting that, in female rats, AMPK activation prevails over stress-induced effects.

Fatty Liver Index for Predicting Nonalcoholic Fatty Liver Disease in an Asymptomatic Korean Population

Nonalcoholic fatty liver disease (NAFLD) is increasing worldwide, highlighting the importance of early and accurate detection and the appropriate management of NAFLD. However, ultrasonography (US) is not included in many mass screening programs, and people have limited access to it. The aim of this study is to validate the fatty liver index (FLI) and investigate the optimal cutoff value for predicting NAFLD in an asymptomatic population. We conducted a retrospective cohort study in Korea. All subjects who underwent health checkup exams, including abdominal US, controlled attenuation parameter (CAP) and blood testing, were enrolled. Analyses of the area under the receiver operating characteristic curve (AUROC) were used to evaluate the diagnostic accuracy and to calculate the optimal FLI cutoff for US-NAFLD. Among the 4009 subjects (mean age 54.9 years, 83.5% male), the prevalence of US-diagnosed NAFLD and CAP-defined hepatic steatosis was 61.4% and 55.4%. The previously used cutoff of FLI = 60 showed poor performance in predicting US-diagnosed NAFLD, with an AUROC of 0.63 (0.62–0.64), and CAP-defined NAFLD, with an AUROC 0.63 (0.62–0.64). The optimal FLI cutoff values to discriminate fatty liver detected by US were 29 for the entire population, with an AUROC of 0.82 (0.81–0.84). The sex-specific values were 31 for males and 18 for females (sensitivity 72.8% and 73.4%; specificity 74.2% and 85.0%, respectively). The FLI cutoff for US-diagnosed NAFLD can be set as 29 for the entire Korean population. Considering the sex dimorphism in NAFLD, different cutoff values are suggested to predict US-diagnosed NAFLD. These results may be helpful in the accurate non-invasive diagnosis of NAFLD.