Nonalcoholic fatty liver disease (NAFLD) prevention: role of Mediterranean diet and physical activity

Gut microbiota induced epigenetic modifications in the non-alcoholic fatty liver disease pathogenesis

Non-alcoholic fatty liver disease (NAFLD) represents a growing global health concern that can lead to liver disease and cancer. It is characterized by an excessive accumulation of fat in the liver, unrelated to excessive alcohol consumption. Studies indicate that the gut microbiota-host crosstalk may play a causal role in NAFLD pathogenesis, with epigenetic modification serving as a key mechanism for regulating this interaction. In this review, we explore how the interplay between gut microbiota and the host epigenome impacts the development of NAFLD. Specifically, we discuss how gut microbiota-derived factors, such as lipopolysaccharides (LPS) and short-chain fatty acids (SCFAs), can modulate the DNA methylation and histone acetylation of genes associated with NAFLD, subsequently affecting lipid metabolism and immune homeostasis. Although the current literature suggests a link between gut microbiota and NAFLD development, our understanding of the molecular mechanisms and signaling pathways underlying this crosstalk remains limited. Therefore, more comprehensive epigenomic and multi-omic studies, including broader clinical and animal experiments, are needed to further explore the mechanisms linking the gut microbiota to NAFLD-associated genes. These studies are anticipated to improve microbial markers based on epigenetic strategies and provide novel insights into the pathogenesis of NAFLD, ultimately addressing a significant unmet clinical need.

Plasma ALS and Gal-3BP differentiate early from advanced liver fibrosis in MASLD patients

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is estimated to affect 30% of the world's population, and its prevalence is increasing in line with obesity. Liver fibrosis is closely related to mortality, making it the most important clinical parameter for MASLD. It is currently assessed by liver biopsy - an invasive procedure that has some limitations. There is thus an urgent need for a reliable non-invasive means to diagnose earlier MASLD stages.

METHODS

A discovery study was performed on 158 plasma samples from histologically-characterised MASLD patients using mass spectrometry (MS)-based quantitative proteomics. Differentially abundant proteins were selected for verification by ELISA in the same cohort. They were subsequently validated in an independent MASLD cohort (n = 200).

RESULTS

From the 72 proteins differentially abundant between patients with early (F0-2) and advanced fibrosis (F3-4), we selected Insulin-like growth factor-binding protein complex acid labile subunit (ALS) and Galectin-3-binding protein (Gal-3BP) for further study. In our validation cohort, AUROCs with 95% CIs of 0.744 [0.673 - 0.816] and 0.735 [0.661 - 0.81] were obtained for ALS and Gal-3BP, respectively. Combining ALS and Gal-3BP improved the assessment of advanced liver fibrosis, giving an AUROC of 0.796 [0.731. 0.862]. The {ALS; Gal-3BP} model surpassed classic fibrosis panels in predicting advanced liver fibrosis.

CONCLUSIONS

Further investigations with complementary cohorts will be needed to confirm the usefulness of ALS and Gal-3BP individually and in combination with other biomarkers for diagnosis of liver fibrosis. With the availability of ELISA assays, these findings could be rapidly clinically translated, providing direct benefits for patients.

Association Between Different Types of Physical Activity and Hepatic Steatosis and Liver Fibrosis: A Cross-Sectional Study Based on NHANES

BACKGROUND AND AIMS

Many studies have shown a link between physical activity (PA) and nonalcoholic fatty liver disease (NAFLD). However, more research is needed to investigate the relationship between different types of PA and NAFLD. This study aimed to explore the potential link between different types of PA, hepatic steatosis, and liver fibrosis.

STUDY

A cross-sectional study was conducted using the data set from the National Health and Nutrition Examination Survey (NHANES) from 2017 to 2020. A multiple linear regression model was used to examine the linear relationship between different types of PA, the controlled attenuation parameter (CAP), and liver stiffness measurement (LSM). In addition, smoothing curve fitting and threshold effect analysis were used to depict their nonlinear relationship.

RESULTS

This study involved 5933 adults. Multiple linear regression analysis revealed a significantly negative correlation between leisure-time PA and CAP, while the relationship between occupation-related PA, transportation-related PA, and CAP was not significant. Subgroup analysis further revealed that leisure-time PA was significantly negatively correlated with CAP in women and younger age groups (under 60 y old), while the relationship was not significant in men and older age groups. In addition, there was a significant negative correlation between leisure-time PA and liver fibrosis in men.

CONCLUSIONS

Leisure-time PA can prevent hepatic steatosis, and women and young people benefit more. Occupation-related PA is not associated with hepatic steatosis and cannot replace leisure-time PA. In men, increasing leisure-time PA is more effective in preventing liver fibrosis.

Lifestyle interventions in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a dynamic chronic liver disease that develops in close association with metabolic irregularities. Between 2016 and 2019, the global prevalence among adults was reported as 38% and among children and adolescents it was about 10%. NAFLD can be progressive and is associated with increased mortality from cardiovascular disease, extrahepatic cancers and liver complications. Despite these numerous adverse outcomes, no pharmacological treatments currently exist to treat nonalcoholic steatohepatitis, the progressive form of NAFLD. Therefore, the main treatment is the pursuit of a healthy lifestyle for both children and adults, which includes a diet rich in fruits, nuts, seeds, whole grains, fish and chicken and avoiding overconsumption of ultra-processed food, red meat, sugar-sweetened beverages and foods cooked at high heat. Physical activity at a level where one can talk but not sing is also recommended, including leisure-time activities and structured exercise. Avoidance of smoking and alcohol is also recommended. Policy-makers, community and school leaders need to work together to make their environments healthy by developing walkable and safe spaces with food stores stocked with culturally appropriate and healthy food items at affordable prices as well as providing age-appropriate and safe play areas in both schools and neighbourhoods.

The association of dietary and lifestyle indices for hyperinsulinemia with odds of non-alcoholic fatty liver disease in Iranian adults: a case-control study

BACKGROUND

Evidence on the association of insulinemic effects of dietary pattern and other lifestyle factors with the odds of non-alcoholic fatty liver disease (NAFLD) are limited. In the current study, we aimed to examine the association of the empirical dietary index for hyperinsulinemia (EDIH) and empirical lifestyle index for hyperinsulinemia (ELIH) index with the NAFLD odds in the adult population.

METHODS

In the current case-control study, 120 cases of NAFLD and 240 controls aged 20-60 years were included. The ultrasonography test was used to determine NAFLD. We used a validated food frequency questionnaire to collect dietary data of individuals and determine the scores of EDIH. Also, we determined the ELIH score based on diet, body mass index, and physical activity. The odds ratio (OR) of NAFLD was calculated using logistic regression test across EDIH and ELIH tertiles.

RESULTS

The mean ± SD age of subjects (53% men) were 41.8 ± 7.5 years. In the age and sex-adjusted model, there is a significant association between a higher ELIH score and higher odds of NAFLD (OR = 2.74;95%CI:1.51-4.96,P_trend = 0.001). Also, based on the multivariable-adjusted model, after controlling for age and sex, smoking, SES, and dietary intake of energy a remarkable positive association was observed between the higher score of ELIH and the odds of NAFLD (OR = 2.70; 95%CI:1.46-5.01,P_trend = 0.002). However, there is no significant relationship between the higher score of EDIH and NAFLD odds.

CONCLUSIONS

Our results showed that the high insulinemic potential of lifestyle, determined by the ELIH score, can be related to an increased NAFLD odds. However, no significant association was found between higher EDIH score and odds of NAFLD.

Dietary Acid Load (DAL), Glycated Hemoglobin A1c (HbA1c), and Metabolic Syndrome (MeS) Mediate the Association of the Adherence to the Dietary Approaches to Stopping Hypertension (DASH) and Mediterranean Diet (MeD) With Nonalcoholic Fatty Liver Disease

The study aimed to investigate the association of adults adhering to Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diet (MeD) with nonalcoholic fatty liver disease (NAFLD) using structural equation modeling (SEM) in Iran. In this population-based cross-sectional study, 3,220 adults (44.65% female) aged ≥18 years were selected from the Amol Cohort Study (AmolCS). The dietary intakes were assessed by a validated 168-item semi-quantitative food-frequency questionnaire (FFQ). Residual method energy adjustment of MeD and DASH scores were calculated. Demographic characteristics and anthropometric and laboratory measurements were collected. NAFLD was diagnosed by an expert radiologist via ultrasound sonography. Based on the primary hypothesis, DASH, MeD, and NAFLD were fitted into models. Metabolic syndrome (MeS) as a potential risk factor directly affected NAFLD risk in all these models. In both genders, the higher adherence to DASH negatively affected NAFLD risk indirectly through the two following paths. (1) Dietary acid load (DAL) and metabolic syndrome (2) DAL and hemoglobin A1c (HbA1c). In addition, the higher DAL positively affected NAFLD risk among male participants indirectly via increasing HbA1c level and MeS (from DAL to HbA1c: β = 0.07, P < 0.001; from HbA1c to MeS: β = 0.10, P < 0.001). Similarly, in both genders, the relationship between MeD and NAFLD was mediated through (1) DAL, HbA1c, and MeS and (2) DAL and MeS. Further, among male participants, the MeD and NAFLD risk were also associated via the mediators of HbA1c and MeS. In female participants, the higher MeD score was directly associated with a reduction of NAFLD risk (β = -0.07, P = 0.008). The present study found three important mediators, including DAL, HbA1c, and MeS, in the association of DASH and MeD scores with NAFLD risk. Preventive and therapeutic interventions should target the mediators, including DAL, HbA1c, MeS, and its components, to reduce NAFLD incidence in the general population.

MAFLD/NAFLD Biopsy-Free Scoring Systems for Hepatic Steatosis, NASH, and Fibrosis Diagnosis

Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly known as nonalcoholic fatty liver disease, is the most prevalent liver disorder worldwide. Historically, its diagnosis required biopsy, even though the procedure has a variable degree of error. Therefore, new non-invasive strategies are needed. Consequently, this article presents a thorough review of biopsy-free scoring systems proposed for the diagnosis of MAFLD. Similarly, it compares the severity of the disease, ranging from hepatic steatosis (HS) and nonalcoholic steatohepatitis (NASH) to fibrosis, by contrasting the corresponding serum markers, clinical associations, and performance metrics of these biopsy-free scoring systems. In this regard, defining MAFLD in conjunction with non-invasive tests can accurately identify patients with fatty liver at risk of fibrosis and its complications. Nonetheless, several biopsy-free scoring systems have been assessed only in certain cohorts; thus, further validation studies in different populations are required, with adjustment for variables, such as body mass index (BMI), clinical settings, concomitant diseases, and ethnic backgrounds. Hence, comprehensive studies on the effects of age, morbid obesity, and prevalence of MAFLD and advanced fibrosis in the target population are required. Nevertheless, the current clinical practice is urged to incorporate biopsy-free scoring systems that demonstrate adequate performance metrics for the accurate detection of patients with MAFLD and underlying conditions or those with contraindications of biopsy.

Is there an association between non-alcoholic fatty liver disease and cognitive function? A systematic review

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is represented as the most common liver disease worldwide. NAFLD is associated with metabolic risk factors underpinned by insulin resistance, inflammation and endothelial dysfunction, leading to extrahepatic changes in central nervous diseases such as cognitive impairment, Alzheimer's disease and dementia. The aim of the review is to explore the association between NAFLD and cognitive function.

METHODS

Using the PRISMA guidelines, a systematic electronic literature search was conducted in four databases: MEDLINE, PsychINFO, Embase and CINAHL from inception until March 2021. Neuropsychological tests utilised within each study were grouped into relevant cognitive domains including 'general cognition', 'reasoning', 'mental speed, attention and psychomotor speed', 'memory and learning', 'language', 'visuospatial perception' and 'ideas, abstraction, figural creations and mental flexibility'.

RESULTS

Eleven observational studies that involved 7978 participants with a mean age of 51 years were included. Those with NAFLD had poor cognitive performance in three cognitive domains, including 'general cognition', 'mental speed, attention and psychomotor speed', and 'ideas, abstraction, figural creations and mental flexibility'.

CONCLUSION

The observed results from the 11 included studies showed that NAFLD was associated with lower cognitive performance across several domains. However, studies conducted to date are limited to observational designs and are heterogeneous with varying diagnostic tools used to assess cognitive function.

TRIAL REGISTRATION

PROSPERO Registration: CRD42020161640 .

Gut microbiome signatures distinguish type 2 diabetes mellitus from non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is closely associated with type 2 diabetes mellitus (T2D), and these two metabolic diseases demonstrate bidirectional influences. The identification of microbiome profiles that are specific to liver injury or impaired glucose metabolism may assist understanding of the role of the gut microbiota in the relationship between NAFLD and T2D. Here, we studied a biopsy-proven Asian NAFLD cohort (n = 329; 187 participants with NAFLD, 101 with NAFLD and T2D, and 41 with neither) and identified Enterobacter, Romboutsia, and Clostridium sensu stricto as the principal taxa associated with the severity of NAFLD and T2D, whereas Ruminococcus and Megamonas were specific to NAFLD. In particular, the taxa that were associated with both severe liver pathology and T2D were also significantly associated with markers of diabetes, such as fasting blood glucose and Hb1Ac. Enterotype analysis demonstrated that participants with NAFLD had a significantly higher proportion of Bacteroides and a lower proportion of Ruminococcus than a Korean healthy twin cohort (n = 756). However, T2D could not be clearly distinguished from NAFLD. Analysis of an independent T2D cohort (n = 185) permitted us to validate the T2D-specific bacterial signature identified in the NAFLD cohort. Functional inference analysis revealed that endotoxin biosynthesis pathways were significantly enriched in participants with NAFLD and T2D, compared with those with NAFLD alone. These findings may assist with the development of effective therapeutic approaches for metabolic diseases that are associated with specific bacterial signatures.

Effects of Lingonberry (Vaccinium vitis-idaea L.) Supplementation on Hepatic Gene Expression in High-Fat Diet Fed Mice

The prevalence of nonalcoholic fatty liver disease (NAFLD) is growing worldwide in association with Western-style diet and increasing obesity. Lingonberry (Vaccinium vitis-idaea L.) is rich in polyphenols and has been shown to attenuate adverse metabolic changes in obese liver. This paper investigated the effects of lingonberry supplementation on hepatic gene expression in high-fat diet induced obesity in a mouse model. C57BL/6N male mice were fed for six weeks with either a high-fat (HF) or low-fat (LF) diet (46% and 10% energy from fat, respectively) or HF diet supplemented with air-dried lingonberry powder (HF + LGB). HF diet induced a major phenotypic change in the liver, predominantly affecting genes involved in inflammation and in glucose and lipid metabolism. Lingonberry supplementation prevented the effect of HF diet on an array of genes (in total on 263 genes) associated particularly with lipid or glucose metabolic process (such as Mogat1, Plin4, Igfbp2), inflammatory/immune response or cell migration (such as Lcn2, Saa1, Saa2, Cxcl14, Gcp1, S100a10) and cell cycle regulation (such as Cdkn1a, Tubb2a, Tubb6). The present results suggest that lingonberry supplementation prevents HF diet-induced adverse changes in the liver that are known to predispose the development of NAFLD and its comorbidities. The findings encourage carrying out human intervention trials to confirm the results, with the aim of recommending the use of lingonberries as a part of healthy diet against obesity and its hepatic and metabolic comorbidities.

Comparative study of the effects of Abexol and atorvastatin in patients with non-alcoholic fatty liver disease

AIM OF THE STUDY

To investigate the efficacy and safety of Abexol and atorvastatin in patients with non-alcoholic fatty liver disease (NAFLD).Material and methods: The present study had a monocentric, randomized, double-blinded, comparative design with 4 parallel groups - group 1 (Abexol), group 2 (atorvastatin), group 3 (combined therapy) and group 4 (placebo) - to which dietary recommendations and physical activity practice were provided twice a day, for 24 weeks. Significant changes in the ultrasound analysis of the liver were considered a primary efficacy variable. Insulin resistance improvement (HOMA2-IR) was considered as a co-primary efficacy criterion. Significant changes in the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), lipid profile variables and the anthropometric variables were evaluated as secondary variables of effectiveness. Statistical analysis of all data was according to the intention to treat method.

RESULTS

The groups were statistically homogeneous at baseline conditions. At the end of the 6 months of treatment about 50% of the patients in all groups showed a decrease of at least one degree in echogenicity, while the rest remained the same. There were no significant changes in the values of liver enzymes or anthropometric variables evaluated. Treatment with atorvastatin and combined therapy significantly reduced levels of low-density lipoprotein-cholesterol (LDL-C) and total cholesterol. The treatments were safe and well tolerated, although in the atorvastatin group the number of adverse events reported was greater than in the rest of the groups.

CONCLUSIONS

Abexol and atorvastatin showed comparable efficacy and safety in patients with NAFLD, with advantages for treatment with atorvastatin with respect to its effects on the lipid profile of these patients.

Lipidomics in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disorder in Western countries, comprises steatosis to nonalcoholic steatohepatitis (NASH), with the latter having the potential to progress to cirrhosis. The transition from isolated steatosis to NASH is still poorly understood, but lipidomics approach revealed that the hepatic lipidome is extensively altered in the setting of steatosis and steatohepatitis and these alterations correlate with disease progression. Recent data suggest that both quantity and quality of the accumulated lipids are involved in pathogenesis of NAFLD. Changes in glycerophospholipid, sphingolipid, and fatty acid composition have been described in both liver biopsies and plasma of patients with NAFLD, implicating that specific lipid species are involved in oxidative stress, inflammation, and cell death. In this article, we summarize the findings of main human lipidomics studies in NAFLD and delineate the currently available information on the pathogenetic role of each lipid class in lipotoxicity and disease progression.

Albumin binding function is a novel biomarker for early liver damage and disease progression in non-alcoholic fatty liver disease

PURPOSE

Indicators to assess early liver damage and disease progression in nonalcoholic fatty liver disease (NAFLD) remain unsatisfactory. Albumin binding function has been reported to be an early indicator of liver damage in hepatitis and liver cirrhosis. However, its role in NAFLD patients is unknown.

METHODS

An age/sex-matched, case-control study was performed. Albumin-binding capacity (ABiC) and albumin metal ion binding ability, assessed by ischemia modified albumin (IMA), were measured. Correlation analysis was performed to assess the association of albumin binding function with liver function enzymes and noninvasive liver fibrosis markers.

RESULTS

A total of 80 NAFLD patients and 41 healthy controls were included. Albumin binding function was significantly lower in NAFLD (ABiC: 196.00%, p < 0.001; IMA transformed (IMAT): 0.461, p < 0.001; and IMAT/albumin: 0.947 × 10^-2, p < 0.001) than controls (ABiC: 211.00%; IMAT: 0.575; and IMAT/albumin: 1.206 × 10^-2). Albumin binding function was also found to be significantly different among healthy participants and different severity groups of NAFLD (p < 0.001). Besides, albumin binding function showed positive correlation with BMI (ABiC: r = -0.247, p = 0.011; IMAT: r = -0.243, p = 0.013; IMAT/albumin: r = -0.254, p = 0.009) and FIB-4 index (ABiC: r = 0.230, p = 0.029). The ROC curve suggested that albumin binding function combined with BMI and triglyceride may predict the presence of NAFLD (area under ROC (AUROC) = 0.935, p < 0.001).

CONCLUSION

Our findings suggest albumin binding function is a novel biomarker for early liver damage and disease progression in NAFLD.

Kupffer Cells in Non-alcoholic Fatty Liver Disease: Friend or Foe?

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing all around the world and it may become the primary cause of terminal liver disease in adults and children in the next few decades. However, the pathogenesis of NAFLD is complex, and the Food and Drug Administration (FDA) has not approved any drugs for its treatment. Kupffer cells are the key cells regulating immunity in the liver, and the effect of their unique polarization on NAFLD has received increasing attention. Kupffer cells mainly reside in the lumen of hepatic sinusoids and account for 80% to 90% of colonized macrophages in the human body. They are phagocytic cells with the capacity for self-renewal that rarely migrate from their niche in the liver, and play a crucial role in regulating and maintaining homeostasis. Upon liver damage, Kupffer cells will be activated, releasing a good deal of inflammatory cytokines and chemokines. This review summarizes the multiple roles of Kupffer cells in the pathogenesis of NAFLD, the role of infiltrating macrophages in the pathogenesis of NAFLD is also briefly discussed, and aims to provide a theoretical basis for designing an NAFLD treatment strategy with Kupffer cells as the therapeutic target.

Therapeutic advances in non-alcoholic fatty liver disease: A microbiota-centered view

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent metabolic disorder with steadily increasing incidence rates worldwide, especially in the West. There are no drugs available at present to treat NAFLD, and the primary therapeutic options include weight loss and the combination of healthy diet and exercise. Therefore, novel interventions are required that can target the underlying risk factors. Gut microbiota is an "invisible organ" of the human body and vital for normal metabolism and immuno-modulation. The number and diversity of microbes differ across the gastrointestinal tract from the mouth to the anus, and is most abundant in the intestine. Since dysregulated gut microbiota is an underlying pathological factor of NAFLD, it is a viable therapeutic target that can be modulated by antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and microbial metabolites. In this review, we summarize the most recent advances in gut microbiota-targeted therapies against NAFLD in clinical and experimental studies, and critically evaluate novel targets and strategies for treating NAFLD.

Benefits of the Therapy With Abexol in Patients With Non-Alcoholic Fatty Liver Disease

Background

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of diseases ranging from steatosis to steatohepatitis and cirrhosis. Given the increasing incidence of NAFLD and the long-term consequences of this disease, it is important to identify the risk factors and therapeutic measures. Abexol is a mixture of beeswax alcohols with antioxidant, gastro-protective and anti-inflammatory effects. The aim was to conduct a pooled analysis of clinical trials data of the effects of Abexol treatment in patients with NAFLD.

Methods

The present analysis includes the data of all patients with NAFLD obtained from medium-term randomized, double-blinded, placebo controlled clinical studies with Abexol. One hundred patients with NAFLD received Abexol (100 mg/day) or placebo for 6 months. Significant changes in the ultrasound analysis of the liver were considered a primary efficacy variable. Secondary endpoints were decreased homeostasis model assessment (HOMA) index and insulin levels, and improved clinical symptoms. Statistical analysis of all data was according to the intention-to-treat method.

Results

Both groups were statistically homogeneous at baseline conditions. At 6 months of treatment, the number of Abexol-treated patients exhibiting a normal liver echo pattern on ultrasonography was greater than that of the placebo patients (P < 0.05). Abexol significantly reduced (P < 0.05) insulin levels and HOMA index. The proportion of Abexol patients showing symptom improvement was higher (P < 0.01) than that of the placebo group. Treatments were safe and well tolerated.

Conclusions

Treatment of Abexol during 6 months significantly ameliorates liver fat accumulation and insulin resistances, meanwhile improving clinical evolution in patients with NAFLD. The treatment was safe and well tolerated in these patients.

Diet Quality Association with Nonalcoholic Fatty Liver Disease by Cirrhosis Status: The Multiethnic Cohort

BACKGROUND

Epidemiological data on the role of overall dietary patterns in nonalcoholic fatty liver disease (NAFLD) are limited, especially from population-based prospective studies.

OBJECTIVES

We investigated the associations between dietary patterns assessed by predefined diet quality indexes (DQIs) and NAFLD risk by cirrhosis status in African Americans, Japanese Americans, Latinos, Native Hawaiians, and whites from the Multiethnic Cohort (MEC).

METHODS

A nested case-control analysis was conducted within the MEC. NAFLD cases were identified by linkage to 1999-2016 Medicare claims. Four DQIs-Healthy Eating Index (HEI)-2015, Alternative Healthy Eating Index-2010, alternate Mediterranean diet score, and Dietary Approaches to Stop Hypertension (DASH) score-were calculated from a validated FFQ administered at baseline. Conditional logistic regression was used to estimate the ORs and 95% CIs with adjustment for multiple covariates.

RESULTS

Analyses included 2959 NAFLD cases (509 with cirrhosis; 2450 without cirrhosis) and 29,292 matched controls. Higher scores for HEI-2015 (i.e., highest compared with lowest quintile OR: 0.83; 95% CI: 0.73, 0.94; P for trend = 0.002) and DASH (OR: 0.78; 95% CI: 0.69, 0.89; P for trend < 0.001), reflecting favorable adherence to a healthful diet, were inversely associated with NAFLD risk. Whereas there were no differences by sex or race/ethnicity, the inverse association was stronger for NAFLD with cirrhosis than for NAFLD without cirrhosis (P for heterogeneity = 0.03 for HEI-2015 and 0.05 for DASH).

CONCLUSIONS

Higher HEI-2015 and DASH scores were inversely associated with NAFLD risk in this ethnically diverse population. The findings suggest that having better diet quality may reduce NAFLD risk with more benefit to NAFLD with cirrhosis.

Identification of hub genes and key pathways of dietary advanced glycation end products‑induced non‑alcoholic fatty liver disease by bioinformatics analysis and animal experiments

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease. Advanced glycation end products (AGEs) negatively affect the liver and accelerate NAFLD progression; however, the underlying mechanisms remain unclear. The present study aimed to examine the effect and mechanism of dietary AGEs on the mouse liver using bioinformatics and in vivo experimental approaches. Gene expression datasets associated with NAFLD were obtained from the Gene Expression Omnibus and differentially expressed genes (DEGs) were identified using GEO2R. Functional enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery and a protein-protein interaction network for the DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes database. MCODE, a Cytoscape plugin, was subsequently used to identify the most significant module. The key genes involved were verified in a dietary AGE-induced non-alcoholic steatohepatitis (NASH) mouse model using reverse transcription-quantitative PCR (RT-qPCR). The 462 DEGs associated with NAFLD in the two datasets, of which 34 overlapping genes were found in two microarray datasets. Functional analysis demonstrated that the 34 DEGs were enriched in the ‘PPAR signaling pathway’, ‘central carbon metabolism in cancer’, and ‘cell adhesion molecules (CAMs)’. Moreover, four hub genes (cell death-inducing DFFA-like effector a, cell death-inducing DFFA-like effector c, fatty acid-binding protein 4 and perilipin 4) were identified from a protein-protein interaction network and were verified using RT-qPCR in a mouse model of NASH. The results suggested that AGEs and their receptor axis may be involved in NAFLD onset and/or progression. This integrative analysis identified candidate genes and pathways in NAFLD, as well as DEGs and hub genes related to NAFLD progression in silico and in vivo.