Pathogenesis and treatment of non-alcoholic steatohepatitis and its fibrosis

Liver-based inter-organ communication: A disease perspective

Inter-organ communication through hormones, cytokines and extracellular vesicles (EVs) has emerged to contribute to the physiological states and pathological processes of the human body. Notably, the liver coordinates multiple tissues and organs to maintain homeostasis and maximize energy utilization, with the underlying mechanisms being unraveled in recent studies. Particularly, liver-derived EVs have been found to play a key role in regulating health and disease. As an endocrine organ, the liver has also been found to perform functions via the secretion of hepatokines. Investigating the multi-organ communication centered on the liver, especially in the manner of EVs and hepatokines, is of great importance to the diagnosis and treatment of liver-related diseases. This review summarizes the crosstalk between the liver and distant organs, including the brain, the bone, the adipose tissue and the intestine in noticeable situations. The discussion of these contents will add to a new dimension of organismal homeostasis and shed light on novel theranostics of pathologies.

Atf3-mediated metabolic reprogramming in hepatic macrophage orchestrates metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH) is regulated by complex interplay between the macrophages and surrounding cells in the liver. Here, we show that Atf3 regulates glucose-fatty acid cycle in macrophages attenuates hepatocyte steatosis, and fibrogenesis in hepatic stellate cells (HSCs). Overexpression of Atf3 in macrophages protects against the development of MASH in Western diet-fed mice, whereas Atf3 ablation has the opposite effect. Mechanistically, Atf3 improves the reduction of fatty acid oxidation induced by glucose via forkhead box O1 (FoxO1) and Cd36. Atf3 inhibits FoxO1 activity via blocking Hdac1-mediated FoxO1 deacetylation at K242, K245, and K262 and increases Zdhhc4/5-mediated CD36 palmitoylation at C3, C7, C464, and C466; furthermore, macrophage Atf3 decreases hepatocytes lipogenesis and HSCs activation via retinol binding protein 4 (Rbp4). Anti-Rbp4 can prevent MASH progression that is induced by Atf3 deficiency in macrophages. This study identifies Atf3 as a regulator of glucose-fatty acid cycle. Targeting macrophage Atf3 or Rbp4 may be a plausible therapeutic strategy for MASH.

Association between SII and markers of liver injury: A cross-sectional study from the NHANES (2017-2020)

INTRODUCTION

A novel indicator of inflammation is the systemic immune-inflammation index (SII), and liver dysfunction is linked to the advancement of inflammation. In light of this, this study aims to look into any potential connections between SII and markers of liver injury.

METHODS

A cross-sectional study was conducted using the National Health and Nutrition Examination (NHANES) dataset for 2017-2020. The linear relationship between SII and markers of liver injury was examined using multiple linear regression models. Examining threshold effects and fitted smoothed curves were utilized to describe nonlinear connections.

RESULTS

A total of 8213 adults aged 18-80 years participated in this population-based study. In the fully adjusted model, SII maintained a negative association with ALT(β = -0.003, 95%CI:-0.005, -0.002, P<0.00001), AST(β = -0.004, 95% CI:-0.005, -0.002, P<0.00001), and GGT(β = -0.004, 95% CI:-0.007, -0.000, P = 0.03791) and a positive association with ALP (β = 0.005, 95% CI:0.003, 0.007, P<0.00001). In subgroup analyses, it was found that SII remained negatively correlated with ALT, AST and GGT in gender, age and body mass index. SII was positively correlated with ALP at BMI≥25(kg/m2)(β = 0.005, 95% CI:0.003, 0.008, P = 0.00001), and was negatively correlated with ALT(β = -0.004, 95% CI:-0.005, -0.002, P<0.00001), AST(β = -0.004, 95% CI:-0.005, -0.003, P<0.00001) and GGT(β = -0.004, 95% CI:-0.008, -0.000, P = 0.02703) at BMI≥25, whereas no significant correlation was observed at BMI<25 (all P-values>0.05). Furthermore, the association between SII and markers of liver injury was nonlinear. By using a two-stage linear regression model for analysis, a U-shaped relationship was found to exist between SII and ALT with a turning point of 818.40(1,000 cells/μl). The inflection points of SII with AST and GGT were 451.20 (1,000 cells/μl) and 443.33 (1,000 cells/μl), respectively, and no significant inflection point with ALP was observed. Interaction tests demonstrated that SII correlation with ALT, AST, ALP, and GGT was not significantly different between strata (all p for interaction>0.05).

CONCLUSIONS

The research findings suggested that there was a negative correlation between SII and ALT, AST and GGT, and a positive correlation with ALP. However, larger prospective investigations are still greatly needed to confirm the findings.

Usefulness of Body Fat and Visceral Fat Determined by Bioimpedanciometry versus Body Mass Index and Waist Circumference in Predicting Elevated Values of Different Risk Scales for Non-Alcoholic Fatty Liver Disease

BACKGROUND

Obesity constitutes a public health problem worldwide and causes non-alcoholic fatty liver disease (MALFD), the leading cause of liver disease in developed countries, which progresses to liver cirrhosis and liver cancer. MAFLD is associated with obesity and can be evaluated by validated formulas to assess MAFLD risk using different parameters such as the body mass index (BMI) and waist circumference (WC). However, these parameters do not accurately measure body fat. As MAFLD is strongly associated with obesity, we hypothesize that measuring body and visceral fat by electrical bioimpedance is an efficient method to predict the risk of MAFLD. The objective of our work was to demonstrate that electrical bioimpedance is a more efficient method than the BMI or WC to predict an elevated risk of MAFLD.

METHODS

A cross-sectional, descriptive study involving 8590 Spanish workers in the Balearic Islands was carried out. The study's sample of employees was drawn from those who underwent occupational medicine examinations between January 2019 and December 2020. Five MAFLD risk scales were determined for evaluating very high levels of body fat and visceral fat. The determination of body and visceral fat was performed using bioimpedanciometry. Student's t-test was employed to ascertain the mean and standard deviation of quantitative data. The chi-square test was used to find prevalences for qualitative variables, while ROC curves were used to define the cut-off points for body and visceral fat. The calculations included the area under the curve (AUC), the cut-off points along with their Youden index, sensitivity, and specificity. Correlation and concordance between the various scales were determined using Pearson's correlation index and Cohen's kappa, respectively.

RESULTS

As both total body fat and visceral fat increase, the risk of MAFLD increases with a statistically significant result (p < 0.001), presenting a higher risk in men. The areas under the curve (AUC) of the five scales that assess overweight and obesity to determine the occurrence of high values of the different MAFLD risk scales were very high, most of them exceeding 0.9. These AUC values were higher for visceral and body fat than for the BMI or waist circumference. FLD-high presented the best results in men and women with the AUC at around 0.97, both for visceral fat and total body fat, with a high Youden index in all cases (women body fat = 0.830, visceral fat = 0.892; men body fat = 0.780, visceral fat = 0.881).

CONCLUSIONS

In our study, all the overweight and obesity scales show a very good association with the scales assessing the risk of MAFLD. These values are higher for visceral and body fat than for waist circumference and the BMI. Both visceral fat and body fat are better associated than the BMI and waist circumference with MAFLD risk scales.

Bariatric intervention improves metabolic dysfunction-associated steatohepatitis in patients with obesity: A systematic review and meta-analysis

BACKGROUND/AIMS

Bariatric intervention has been reported to be an effective way to improve metabolic dysfunction-associated steatotic liver disease (MASLD) in obese individuals. The current systemic review aimed to assess the changes in MRI-determined hepatic proton density fat fraction (MRI-PDFF) and nonalcoholic fatty liver disease activity score (NAS) after bariatric surgery or intragastric balloon/gastric banding in MASLD patients with obesity.

METHODS

We searched various databases including PubMed, OVID Medline, EMBASE, and Cochrane Library. Primary outcomes were the changes in intrahepatic fat on MRI-PDFF and histologic features of metabolic dysfunction-associated steatohepatitis (MASH).

RESULTS

Thirty studies with a total of 3,134 patients were selected for meta-analysis. Bariatric intervention significantly reduced BMI (ratio of means, 0.79) and showed 72% reduction of intrahepatic fat on MRI-PDFF at 6 months after bariatric intervention (ratio of means, 0.28). Eight studies revealed that NAS was reduced by 60% at 3-6 months compared to baseline, 40% at 12-24 months, and 50% at 36-60 months. Nineteen studies revealed that the proportion of patients with steatosis decreased by 44% at 3-6 months, 37% at 12-24 months, and 29% at 36-60 months; lobular inflammation by 36% at 12-24 months and 51% at 36-60 months; ballooning degeneration by 38% at 12-24 months; significant fibrosis (≥F2) by 18% at 12-24 months and by 17% at 36-60 months after intervention.

CONCLUSION

Bariatric intervention significantly improved MRI-PDFF and histologic features of MASH in patients with obesity. Bariatric intervention might be the effective alternative treatment option for patients with MASLD who do not respond to lifestyle modification or medical treatment.

Changes in alanine aminotransferase and body composition and metabolic factors among individuals receiving medical health checkups

AIM

To examine the relationship between changes in alanine aminotransferase (ALT) and those in body composition and metabolic factors in participants receiving medical health checkups (4350 men [mean age 52.5 years] and 5398 women [mean age 50.5 years]) METHODS: We divided the participants into four types based on their ALT value at baseline and 1 year: A, ALT ≤30 (baseline) and ≤30 (1 year); B, ALT ≥31 (baseline) and ≤30 (1 year); C, ALT ≤30 (baseline) and ≥31 (1 year); and D, ALT ≥31 (baseline) and ≥31 (1 year). The change in each body composition-related parameter (waist circumference, fat mass, fat-free mass, fat mass to fat-free mass ratio, etc.) after 1-year was defined as Δ.

RESULTS

The mean changes in waist circumference (cm) in the four types (A, B, C, and D) were -0.33, -1.54, 0.66, and -0.29 (overall p < 0.0001) in men, and -0.19, -0.90, 0.30, and 0.090 (overall p < 0.0001) in women. The mean changes in fat mass (kg) in the four types were -0.027, -0.86, 0.62, and 0.092 (overall p < 0.0001) in men, and 0.0067, -0.48, 0.39, and 0.063 (overall p < 0.0001) in women. The mean changes in fat-free mass (kg) in the four types were -0.028, -0.55, 0.42, and -0.034 (overall p < 0.0001) in men, and -0.0091, -0.34, 0.12, and -0.045 (overall p = 0.0012) in women. The mean changes in fat mass to fat-free mass ratio in the four types were -0.00042, -0.0120, 0.00837, and 0.00171 (overall p < 0.0001) in men, and -0.00013, -0.00817, 0.00730, and 0.00628 (overall p < 0.0001) in women.

CONCLUSION

A decrease in ALT to ≤30 IU/L may be associated with improved body composition balance, but caution should be exercised for the decrease in muscle mass.

MAFLD Pandemic: Updates in Pharmacotherapeutic Approach Development

With around one billion of the world's population affected, the era of the metabolic-associated fatty liver disease (MAFLD) pandemic has entered the global stage. MAFLD is a chronic progressive liver disease with accompanying metabolic disorders such as type 2 diabetes mellitus and obesity which can progress asymptomatically to liver cirrhosis and subsequently to hepatocellular carcinoma (HCC), and for which to date there are almost no approved pharmacologic options. Because MAFLD has a very complex etiology and it also affects extrahepatic organs, a multidisciplinary approach is required when it comes to finding an effective and safe active substance for MAFLD treatment. The optimal drug for MAFLD should diminish steatosis, fibrosis and inflammation in the liver, and the winner for MAFLD drug authorisation seems to be the one that significantly improves liver histology. Saroglitazar (Lipaglyn®) was approved for metabolic-dysfunction-associated steatohepatitis (MASH) in India in 2020; however, the drug is still being investigated in other countries. Although the pharmaceutical industry is still lagging behind in developing an approved pharmacologic therapy for MAFLD, research has recently intensified and many molecules which are in the final stages of clinical trials are expected to be approved in the coming few years. Already this year, the first drug (Rezdiffra™) in the United States was approved via accelerated procedure for treatment of MAFLD, i.e., of MASH in adults. This review underscores the most recent information related to the development of drugs for MAFLD treatment, focusing on the molecules that have come furthest towards approval.

Preventing High Fat Diet-Induced Obesity and Related Hepatic Steatosis by Chlorin e6-Mediated Photodynamic Therapy

Obesity and its associated hepatic steatosis have become a global concern, posing numerous health hazards. Photodynamic therapy (PDT) is a unique approach that promotes anti-obesity by releasing intracellular fat. Chlorin e6 (Ce6)-PDT was tested for its anti-obesity properties in male ovariectomized (OVX) beagle dogs, as well as male C57BL/6 and Balb/c mice. The 12 OVX beagles were randomly assigned to one of four groups: high-fat diet (HFD) only, Ce6 only, Ce6 + 10 min of light-emitting diode light (LED) treatment, and Ce6 + 15 min of light treatment. We assessed several parameters, such as body weight, adipose tissue morphology, serum biochemistry, and body fat content analysis by computed tomography (CT) scan in HFD-fed beagle dogs. At the end of the study period, dogs that were treated for 35 days with Ce6 and exposed to LED irradiation (660 nm) either for 10 min (Ce6 + 10 min of light) or for 15 min (Ce6 + 15 min of light) had decreased body weight, including visceral and subcutaneous fats, lower aspartate transaminase (AST)/alanine transaminase (ALT) ratios, and a reduction in the area of individual adipocytes with a concomitant increase in the number of adipocytes. Furthermore, C57BL/6 male mice following an HFD diet were effectively treated by Ce6-PDT treatment through a reduction in weight gain and fat accumulation. Meanwhile, Ce6-PDT attenuated hepatocyte steatosis by decreasing the epididymal adipose tissue and balloon degeneration in hepatocytes in HFD-fed Balb/c mice. Taken together, our results support the idea that Ce6-PDT is a promising therapeutic strategy for the recovery of obesity and obesity-related hepatic steatosis.

STUB1 increases adiponectin expression by inducing ubiquitination and degradation of NR2F2, thereby reducing hepatic stellate cell activation and alleviating non-alcoholic fatty liver disease

BACKGROUND

Adiponectin (APN) has exhibited ameliorating effects on non-alcoholic fatty liver disease (NAFLD). This study investigates the roles of APN and its regulatory molecules in hepatic stellate cell (HSC) activation and the progression of NAFLD.

METHODS

Mice were subjected to a high-fat diet (HFD) to establish NAFLD models. Liver tissue was examined for lipid metabolism, fibrosis, and inflammation. Mouse 3T3-L1 adipocytes were exposed to palmitic acid (PA) to mimic a high-fat environment. The conditioned medium (CM) from adipocytes was collected for the culture of isolated mouse HSCs. Gain- or loss-of-function studies of APN, nuclear receptor subfamily 2 group F member 2 (NR2F2), and STIP1 homology and U-box containing protein 1 (STUB1) were performed to analyze their roles in NAFLD and HSC activation in vivo and in vitro.

RESULTS

APN expression was poorly expressed in HFD-fed mice and PA-treated 3T3-L1 adipocytes, which was attributed to the transcription inhibition mediated by NR2F2. Silencing of NR2F2 restored the APN expression, ameliorating liver steatosis, fibrosis, and inflammatory cytokine infiltration in mouse livers and reducing HSC activation. Similarly, the NR2F2 silencing condition reduced HSC activation in vitro. However, these effects were counteracted by artificial APN silencing. STUB1 facilitated the ubiquitination and protein degradation of NR2F2, and its upregulation mitigated NAFLD-like symptoms in mice and HSC activation, effects reversed by the NR2F2 overexpression.

CONCLUSION

This study highlights the role of STUB1 in reducing HSC activation and alleviating NAFLD by attenuating NR2F2-mediated transcriptional repression of APN.

Deciphering the molecular pathways of saroglitazar: A dual PPAR α/γ agonist for managing metabolic NAFLD

Saroglitazar (SARO), a dual peroxisome proliferator activated receptor (PPAR)-α/γ agonist, has been used to treat metabolic diseases such as insulin resistance and diabetic dyslipidemia in patients with non-alcoholic fatty liver disease (NAFLD). SARO, administered at a dose of 4 mg/day, has been consistently studied in clinical trials with different time points ranging from 4 to 24 weeks with NAFLD patients. Due to its PPAR-γ agonistic action, SARO prevents adipose tissue-mediated fatty acid delivery to the liver by increasing insulin sensitivity and regulating adiponectin and leptin levels in adipose tissue. In hepatocytes, SARO induces fatty acid β-oxidation in mitochondria and transcriptionally activates lipid metabolizing genes in peroxisomes. SARO inhibits insulin resistance, thereby preventing the activation of sterol regulatory element-binding proteins -1c and carbohydrate response element binding protein in hepatocytes through its PPAR-α agonistic action. SARO treatment reduces lipotoxicity-mediated oxidative stress by activating the nuclear factor erythroid 2-related factor 2 and transcriptionally expressing the antioxidants from the antioxidant response element in the nucleus through its PPAR-γ agonistic action. SARO provides a PPAR-α/γ-mediated anti-inflammatory effect by preventing the phosphorylation of mitogen-activated protein kinases (JNK and ERK) and nuclear factor kappa B in hepatocytes. Additionally, SARO interferes with transforming growth factor-β/Smad downstream signaling, thereby reducing liver fibrosis progression through its PPAR-α/γ agonistic actions. Thus, SARO improves insulin resistance and dyslipidemia in NAFLD, reduces lipid accumulation in the liver, and thereby prevents mitochondrial toxicity, oxidative stress, inflammation, and fibrosis progression. This review summarizes the possible molecular mechanism of SARO in the NAFLD.

Role of Culinary Indian Spices in the Regulation of TGF-β Signaling Pathway in Inflammation-Induced Liver Cancer

SCOPE

Hepatocellular carcinoma (HCC) results from various etiologies, such as Hepatitis B and C, Alcoholic and Non-alcoholic fatty liver disorders, fibrosis, and cirrhosis. About 80 to 90% of HCC cases possess cirrhosis, which is brought on by persistent liver inflammation. TGF-β is a multifunctional polypeptide molecule that acts as a pro-fibrogenic marker, inflammatory cytokine, immunosuppressive agent, and pro-carcinogenic growth factor during the progression of HCC. The preclinical and clinical evidence illustrates that TGF-β can induce epithelial-to-mesenchymal transition, promoting progression and hepatocyte immune evasion. Therefore, targeting the TGF-β pathway can be a promising therapeutic option against HCC.

METHODS AND RESULTS

We carry out a systemic analysis of eight potentially selected culinary Indian spices: Turmeric, Black pepper, Ginger, Garlic, Fenugreek, Red pepper, Clove, Cinnamon, and their bioactives in regulation of the TGF-β pathway against liver cancer.

CONCLUSION

Turmeric and its active constituent, curcumin, possess the highest therapeutic potential in treating inflammation-induced HCC and they also have the maximum number of ongoing in-vivo and in-vitro studies.

Unraveling the relationship between histone methylation and nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) poses a significant health challenge in modern societies due to shifts in lifestyle and dietary habits. Its complexity stems from genetic predisposition, environmental influences, and metabolic factors. Epigenetic processes govern various cellular functions such as transcription, chromatin structure, and cell division. In NAFLD, these epigenetic tendencies, especially the process of histone methylation, are intricately intertwined with fat accumulation in the liver. Histone methylation is regulated by different enzymes like methyltransferases and demethylases and influences the expression of genes related to adipogenesis. While early-stage NAFLD is reversible, its progression to severe stages becomes almost irreversible. Therefore, early detection and intervention in NAFLD are crucial, and understanding the precise role of histone methylation in the early stages of NAFLD could be vital in halting or potentially reversing the progression of this disease.

Hepatic Stellate Cell-Targeting Micelle Nanomedicine for Early Diagnosis and Treatment of Liver Fibrosis

Diagnosing and treating liver fibrosis is a challenging yet crucial endeavor due to its complex pathogenesis and risk of deteriorating into cirrhosis, liver failure, and even hepatic cancer. Herein, a silica cross-linked micelles (SCLMs) based nano-system is developed for both diagnosing and treating liver fibrosis. The SCLMs are first modified with peptide CTCE9908 (CT-SCLMs) and can actively target CXCR4, which is overexpressed in activated hepatic stellate cells (HSCs). To enable diagnosis, an ONOO--responded near-infrared fluorescent probe NOF2 is loaded into the CT-SCLMs. This nano-system can target the aHSCs and diagnose the liver fibrosis particularly in CCl4-induced liver damage, by monitoring the reactive nitrogen species. Furthermore, a step is taken toward treatment by co-encapsulating two anti-fibrosis drugs, silibinin and sorafenib, within the CT-SCLMs. This combined approach results in a significant alleviation of liver injury. Symptoms associated with liver fibrosis, such as deposition of collagen, expression of hydroxyproline, and raised serological indicators show notable improvement. In summary, the CXCR4-targeted nano-system can serve as a promising theragnostic system of early warning and diagnosis for liver fibrosis, offering hope against progression of this serious liver condition.

Elucidating cuproptosis in metabolic dysfunction-associated steatotic liver disease

Emerging research into metabolic dysfunction-associated steatotic liver disease (MASLD) up until January 2024 has highlighted the critical role of cuproptosis, a unique cell death mechanism triggered by copper overload, in the disease's development. This connection offers new insights into MASLD's complex pathogenesis, pointing to copper accumulation as a key factor that disrupts lipid metabolism and insulin sensitivity. The identification of cuproptosis as a significant contributor to MASLD underscores the potential for targeting copper-mediated pathways for novel therapeutic approaches. This promising avenue suggests that managing copper levels could mitigate MASLD progression, offering a fresh perspective on treatment strategies. Further investigations into how cuproptosis influences MASLD are essential for unraveling the detailed mechanisms at play and for identifying effective interventions. The focus on copper's role in liver health opens up the possibility of developing targeted therapies that address the underlying causes of MASLD, moving beyond symptomatic treatment to tackle the root of the problem. The exploration of cuproptosis in the context of MASLD exemplifies the importance of understanding metal homeostasis in metabolic diseases and represents a significant step forward in the quest for more effective treatments. This research direction lights path for innovative MASLD management and reversal.

Would Combination Be Better: Swimming Exercise and Intermittent Fasting Improve High-Fat Diet-Induced Nonalcoholic Fatty Liver Disease in Obese Rats via the miR-122-5p/SREBP-1c/CPT1A Pathway

Background

Swimming and intermittent fasting can both improve obesity-induced NAFLD, but which of the two is more effective and whether the combination of the two has a superimposed effect is inconclusive.

Methods

The model of NAFLD in obese rats was established by a high-fat diet and performed swimming, intermittent fasting, and a combination of both interventions for 8 weeks. Serum lipids and enzyme activity were measured by an automatic biochemical analyzer. Liver morphostructural analysis was observed by transmission electron microscopy, and morphology was observed by HE staining. RT‒PCR was used to detect the mRNA level.

Results

Morphology and microstructure of the liver of model rats were impaired, with the upregulation of miR-122-5p, SREBP-1c, FASN and ACC1. Eight weeks of swimming exercise, intermittent fasting and the combination of both attenuate these effects, manifested by the downregulation of miR-122-5p and upregulation of CPT1A mRNA levels. There was no significant stacking effect of the combination of the swimming and intermittent fasting interventions.

Conclusion

NAFLD leads to pathology in model rats. Eight weeks of swimming exercise, intermittent fasting and the combination of both can inhibit miR-122-5p and improve hepatic lipid metabolism, while no significant additive effects of combining the interventions were found.

Adherence to an antioxidant diet and lifestyle is associated with reduced risk of cardiovascular disease and mortality among adults with nonalcoholic fatty liver disease: evidence from NHANES 1999-2018

Background

Nonalcoholic fatty liver disease (NAFLD) stands a prevalent chronic liver condition significantly influenced by oxidative stress. We investigated the unclear relationship between antioxidant-rich diet and lifestyle and cardiovascular disease (CVD) prevalence rate and mortality in adult patients with NAFLD.

Methods

This study utilized data from the National Health and Nutrition Examination Survey (NHAENS) spanning from 1999 to 2018 to investigate the association between adherence to an antioxidant-rich diet and lifestyle and the cardiovascular disease (CVD) prevalence rate and mortality in adult patients with NAFLD. The study employed the Oxidative Balance Score (OBS) to define antioxidant diet and lifestyle.

Results

Including 8,670 adult patients with NAFLD, the study revealed an inverse association between OBS and the prevalence of most CVD conditions. Fully adjusted models demonstrated that each unit increase in diet OBS, lifestyle OBS, and overall OBS corresponded to a 2, 7, and 2% reduction in all-cause mortality, respectively. In models 2, findings revealed that lifestyle Q2 and Q3 were linked to reduced cancer mortality, whereas diet and overall OBS did not exhibit an association. Additionally, Stratified analysis revealed that age (<45 years) and education level (> high school) significantly influenced the association between the OBS and the prevalence of CVD.

Conclusion

These results underscore the protective link between adherence to an antioxidant diet and lifestyle and a diminished prevalence of CVD and mortality in adults with NAFLD, particularly among younger and higher-educated populations.

MicroRNA-582-3p knockdown alleviates non-alcoholic steatohepatitis by altering the gut microbiota composition and moderating TMBIM1

BACKGROUND

The gut dysbiosis correlates with non-alcoholic steatohepatitis (NASH), involving the moderation of miRNAs.

AIMS

This study was aimed to investigate the correlation between gut microbiota and miR-582-3p in patients with non-alcoholic steatohepatitis (NASH) and to explore the possible regulation of miR-582-3p in the function of the activated hepatic stellate cells (HSCs).

METHODS

GSE69670 and GSE14435 datasets were analyzed by GEO2R. Plasma and fecal samples were obtained from the subjects, non-steatosis (n = 35), simple steatosis (n = 35), and NASH (n = 35). The variations in intestinal microbiota in the non-steatosis and NASH groups were analyzed using 16S rRNA sequencing. The expression of miR-582-3p among the groups was detected using RT-qPCR. Correlations between top-changed intestinal microbiota and miR-582-3p expression were analyzed using the Pearson correlation coefficient. Target gene identification was performed by prediction and dual-luciferase reporter assay. The effect of miR-582-3p on the cell function of TGF-β1-induced HSCs was assessed in vitro.

RESULTS

miR-582-3p was the common differentially expressed miRNA between GSE69670 and GSE14435. miR-582-3p was upregulated in NASH patients' plasma, as well as in TGF-β1-induced LX-2 cells. The non-steatosis and NASH groups showed significantly different intestinal microbiota distribution. miR-582-3p was positively correlated with specific microbiota populations. TMBIM1 was a target gene for miR-582-3p. Knockdown of miR-582-3p suppressed HSC proliferation and myofibroblast markers' expression but induced cell apoptosis, via TMBIM1.

CONCLUSIONS

This present study suggests that miR-582-3p promotes the progression of NASH. Knockdown of miR-582-3p may alleviate NASH by altering the gut microbiota composition and moderating TMBIM1.

Meta-analysis: Efficacy and safety of fibroblast growth factor 21 analogues for the treatment of non-alcoholic steatohepatitis and non-alcoholic steatohepatitis-related fibrosis

BACKGROUND

Fibroblast growth factor 21 (FGF21) analogues have emerged as promising therapeutic targets for non-alcoholic steatohepatitis (NASH). However, the effects and safety of these analogues on NASH and NASH-related fibrosis remain unexplored.

AIMS

To estimate the efficacy and safety of FGF21 analogues for treating NASH and NASH-related fibrosis.

METHODS

PubMed, Embase, and the Cochrane Library were searched for relevant studies up to 11 October 2023. Primary outcomes were defined as the fibrosis improvement ≥1 stage without worsening of NASH and NASH resolution without worsening fibrosis. Secondary outcomes included biomarkers of fibrosis, liver injury, and metabolism. Treatment-related adverse events were also analysed.

RESULTS

Nine studies, including 1054 patients with biopsy-proven NASH and stage F1-F4 fibrosis, were identified. Seven studies reported histological outcomes. The relative risk (RR) for obtaining fibrosis improvement ≥1 stage efficacy was 1.79 (95% CI 1.29-2.48, I2  = 37%, p < 0.001) with FGF21 analogues relative to placebo. Although no statistically significant difference was observed between FGF21 analogues in NASH resolution, sensitivity analyses and fragility index suggest that this result is unstable. The drugs improved hepatic fat fraction (HFF), along with other biomarkers of fibrosis, liver injury, and metabolism (MRE, LSM, Pro-C3, ELF, ALT, AST, TG, HDL-C, and LDL-C). Additionally, no significant difference in serious adverse event incidence rate was observed (RR = 1.26, 95% CI 0.82-1.94, I2  = 24%, p = 0.3).

CONCLUSIONS

FGF21 analogues appear as promising agents for the treatment of NASH and NASH-related fibrosis, and they generally seem to be safe and well tolerated.

Underlying Mechanisms behind the Brain-Gut-Liver Axis and Metabolic-Associated Fatty Liver Disease (MAFLD): An Update

Metabolic-associated fatty liver disease (MAFLD) includes several metabolic dysfunctions caused by dysregulation in the brain-gut-liver axis and, consequently, increases cardiovascular risks and fatty liver dysfunction. In MAFLD, type 2 diabetes mellitus, obesity, and metabolic syndrome are frequently present; these conditions are related to liver lipogenesis and systemic inflammation. This study aimed to review the connection between the brain-gut-liver axis and MAFLD. The inflammatory process, cellular alterations in hepatocytes and stellate cells, hypercaloric diet, and sedentarism aggravate the prognosis of patients with MAFLD. Thus, to understand the modulation of the physiopathology of MAFLD, it is necessary to include the organokines involved in this process (adipokines, myokines, osteokines, and hepatokines) and their clinical relevance to project future perspectives of this condition and bring to light new possibilities in therapeutic approaches. Adipokines are responsible for the activation of distinct cellular signaling in different tissues, such as insulin and pro-inflammatory cytokines, which is important for balancing substances to avoid MAFLD and its progression. Myokines improve the quantity and quality of adipose tissues, contributing to avoiding the development of MAFLD. Finally, hepatokines are decisive in improving or not improving the progression of this disease through the regulation of pro-inflammatory and anti-inflammatory organokines.

Dietary inflammatory index is associated with metabolic dysfunction-associated fatty liver disease among United States adults

Background

Metabolic dysfunction-associated fatty liver disease (MAFLD) is presently the most prevalent chronic liver disorder globally that is closely linked to obesity, dyslipidemia metabolic syndrome, and type 2 diabetes mellitus (T2DM). Its pathogenesis is strongly associated with inflammation, and diet is a major factor in reducing inflammation. However, current research has focused primarily on exploring the relationship between diet and NAFLD, with less research on its link to MAFLD.

Methods

In this research, using dietary inflammatory index (DII) as a measure to assess dietary quality, we analyzed the relationship between diet and MAFLD. Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018, including 3,633 adults with complete DII and MAFLD, were used to develop cross-sectional analyses. Logistic regression analysis was adapted for investigating the relationship between DII and MAFLD development. Additionally, subgroup analysis and threshold effect analysis were carried out.

Results

A positive link between DII and MAFLD was found in the fully adjusted model (OR = 1.05; 95%CI, 1.00-1.11, p < 0.05). Subgroup analysis indicated that there was no significant dependence for the connection between DII and MAFLD except for the subgroup stratified by age. Compared with other age groups, people with MAFLD had 20% higher DII scores than non-MAFLD participants in those aged 20-41 years old (OR = 1.20; 95%CI, 1.08-1.33, p < 0.001). Furthermore, we found a U-shaped curve with an inflection point of 3.06 illustrating the non-linear connection between DII and MAFLD.

Conclusion

As a result, our research indicates that pro-inflammatory diet may increase the chance of MAFLD development, thus improved dietary patterns as a lifestyle intervention is an important strategy to decrease the incidence of MAFLD.

From NAFLD to MASLD: When metabolic comorbidity matters

INTRODUCTION AND OBJECTIVES

In a recent development, a cohort of hepatologists has proposed altering the nomenclature of non-alcoholic fatty liver disease (NAFLD) to metabolic-associated steatotic liver disease (MASLD), accompanied by modified diagnostic criteria. Our objective was to investigate the effect of the revised definition on identifying significant hepatic fibrosis.

PATIENTS AND METHODS

From Jan 2009 to Dec 2022, a total of 428 patients with biopsy-proven hepatic steatosis were diagnosed with NAFLD. Patients were classified into subgroups according to MASLD and Cryptogenic-SLD diagnostic criteria. The clinical pathological features were compared between these two groups. Risk factors for significant fibrosis were analysed in the MASLD group. In total, 329 (76.9 %) patients were diagnosed with MASLD, and 99 (23.1 %) were diagnosed with Cryptogenic-SLD.

RESULTS

Those with MASLD exhibited a higher degree of disease severity regarding histology features than Cryptogenic-SLD. The prevalence of significant fibrosis increased from 13 % to 26.6 % for one and two criteria present to 42.5 % for meeting three or more cardiometabolic risk factor (CMRF) criteria (p = 0.001). ALB (aOR:0.94,95 %CI:0.90-1.00; p = 0.030), lower levels of PLT (aOR:0.99, 95 %CI:0.99-1.00; p < 0.001), and more metabolic comorbidities (aOR:1.42,95 %CI:1.14-1.78; p = 0.012) were independent risk factors of significant fibrosis in MASLD.

CONCLUSIONS

The new nomenclature of MASLD and SLD is more applicable to identifying significant fibrosis than NAFLD. Patients with three or more cardiometabolic risk factors are at higher risk of fibrosis.

Hypertension and NAFLD risk: Insights from the NHANES 2017-2018 and Mendelian randomization analyses

BACKGROUND

Hypertension and non-alcoholic fatty liver disease (NAFLD) share several pathophysiologic risk factors, and the exact relationship between the two remains unclear. Our study aims to provide evidence concerning the relationship between hypertension and NAFLD by analyzing data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 and Mendelian randomization (MR) analyses.

METHODS

Weighted multivariable-adjusted logistic regression was applied to assess the relationship between hypertension and NAFLD risk by using data from the NHANES 2017-2018. Subsequently, a two-sample MR study was performed using the genome-wide association study (GWAS) summary statistics to identify the causal association between hypertension, systolic blood pressure (SBP), diastolic blood pressure (DBP), and NAFLD. The primary inverse variance weighted (IVW) and other supplementary MR approaches were conducted to verify the causal association between hypertension and NAFLD. Sensitivity analyses were adopted to confirm the robustness of the results.

RESULTS

A total of 3144 participants were enrolled for our observational study in NHANES. Weighted multivariable-adjusted logistic regression analysis suggested that hypertension was positively related to NAFLD risk (odds ratio [OR] = 1.677; 95% confidence interval [CI], 1.159-2.423). SBP ≥130 mmHg and DBP ≥80 mmHg were also significantly positively correlated with NAFLD. Moreover, hypertension was independently connected with liver steatosis ( β = 7.836 [95% CI, 2.334-13.338]). The results of MR analysis also supported a causal association between hypertension (OR = 7.203 [95% CI, 2.297-22.587]) and NAFLD. Similar results were observed for the causal exploration between SBP (OR = 1.024 [95% CI, 1.003-1.046]), DBP (OR = 1.047 [95% CI, 1.005-1.090]), and NAFLD. The sensitive analysis further confirmed the robustness and reliability of these findings (all P >0.05).

CONCLUSION

Hypertension was associated with an increased risk of NAFLD.

Effect of Blueberry Supplementation on a Diet-Induced Rat Model of Prediabetes-Focus on Hepatic Lipid Deposition, Endoplasmic Stress Response and Autophagy

Blueberries, red fruits enriched in polyphenols and fibers, are envisaged as a promising nutraceutical intervention in a plethora of metabolic diseases. Prediabetes, an intermediate state between normal glucose tolerance and type 2 diabetes, fuels the development of complications, including hepatic steatosis. In previous work, we have demonstrated that blueberry juice (BJ) supplementation benefits glycemic control and lipid profile, which was accompanied by an amelioration of hepatic mitochondrial bioenergetics. The purpose of this study is to clarify the impact of long-term BJ nutraceutical intervention on cellular mechanisms that govern hepatic lipid homeostasis, namely autophagy and endoplasmic reticulum (ER) stress, in a rat model of prediabetes. Two groups of male Wistar rats, 8-weeks old, were fed a prediabetes-inducing high-fat diet (HFD) and one group was fed a control diet (CD). From the timepoint where the prediabetic phenotype was achieved (week 16) until the end of the study (week 24), one of the HFD-fed groups was daily orally supplemented with 25 g/kg body weight (BW) of BJ (HFD + BJ). BW, caloric intake, glucose tolerance and insulin sensitivity were monitored throughout the study. The serum and hepatic lipid contents were quantified. Liver and interscapular brown and epidydimal white adipose tissue depots (iBAT and eWAT) were collected for histological analysis and to assess thermogenesis, ER stress and autophagy markers. The gut microbiota composition and the short-chain fatty acids (SCFAs) content were determined in colon fecal samples. BJ supplementation positively impacted glycemic control but was unable to prevent obesity and adiposity. BJ-treated animals presented a reduction in fecal SCFAs, increased markers of arrested iBAT thermogenesis and energy expenditure, together with an aggravation of HFD-induced lipotoxicity and hepatic steatosis, which were accompanied by the inhibition of autophagy and ER stress responses in the liver. In conclusion, despite the improvement of glucose tolerance, BJ supplementation promoted a major impact on lipid management mechanisms at liver and AT levels in prediabetic animals, which might affect disease course.

Machine learning-based integration identifies the ferroptosis hub genes in nonalcoholic steatohepatitis

BACKGROUND

Ferroptosis, is characterized by lipid peroxidation of fatty acids in the presence of iron ions, which leads to cell apoptosis. This leads to the disruption of metabolic pathways, ultimately resulting in liver dysfunction. Although ferroptosis is linked to nonalcoholic steatohepatitis (NASH), understanding the key ferroptosis-related genes (FRGs) involved in NASH remains incomplete. NASH may be targeted therapeutically by identifying the genes responsible for ferroptosis.

METHODS

To identify ferroptosis-related genes and develop a ferroptosis-related signature (FeRS), 113 machine-learning algorithm combinations were used.

RESULTS

The FeRS constructed using the Generalized Linear Model Boosting algorithm and Gradient Boosting Machine algorithms exhibited the best prediction performance for NASH. Eight FRGs, with ZFP36 identified by the algorithms as the most crucial, were incorporated into in FeRS. ZFP36 is significantly enriched in various immune cell types and exhibits significant positive correlations with most immune signatures.

CONCLUSION

ZFP36 is a key FRG involved in NASH pathogenesis.

Mitochondrial Dysfunction in Metabolic Dysfunction Fatty Liver Disease (MAFLD)

Nonalcoholic fatty liver disease (NAFLD) has become an increasingly common disease in Western countries and has become the major cause of liver cirrhosis or hepatocellular carcinoma (HCC) in addition to viral hepatitis in recent decades. Furthermore, studies have shown that NAFLD is inextricably linked to the development of extrahepatic diseases. However, there is currently no effective treatment to cure NAFLD. In addition, in 2020, NAFLD was renamed metabolic dysfunction fatty liver disease (MAFLD) to show that its pathogenesis is closely related to metabolic disorders. Recent studies have reported that the development of MAFLD is inextricably associated with mitochondrial dysfunction in hepatocytes and hepatic stellate cells (HSCs). Simultaneously, mitochondrial stress caused by structural and functional disorders stimulates the occurrence and accumulation of fat and lipo-toxicity in hepatocytes and HSCs. In addition, the interaction between mitochondrial dysfunction and the liver-gut axis has also become a new point during the development of MAFLD. In this review, we summarize the effects of several potential treatment strategies for MAFLD, including antioxidants, reagents, and intestinal microorganisms and metabolites.

Inducible nitric oxide synthase accelerates nonalcoholic fatty liver disease progression by regulating macrophage autophagy

BACKGROUND

Cells and tissues, such as macrophages, express inducible nitric oxide synthase (INOS) after stimulation by certain factors. INOS helps mediate the macrophage inflammatory reaction, but few studies have explored how INOS affects macrophage function in nonalcoholic fatty liver disease (NAFLD).

OBJECTIVE

This study investigated the role of INOS-mediated macrophage activity in NAFLD.

METHODS

A high-fat diet was used to establish an NAFLD mouse model. After 12 weeks, blood was collected for immune cell and lipid analyses, and liver tissues were collected for pathological analyses with hematoxylin and eosin and Oil Red O staining. Peritoneal macrophages were extracted in situ, cultured in Dulbecco's modified Eagle's medium, and stimulated with palmitic acid to mimic in vivo conditions for further assays. Real-time polymerase chain reaction, western blot analysis, and immunofluorescence were used to verify the expression of target genes or proteins.

RESULTS

In the NAFLD model, INOS expression in macrophages increased, and INOS knockdown significantly decreased the number of macrophages. Pathological examinations confirmed that INOS knockdown slowed NAFLD progression and macrophage infiltration during inflammation. INOS knockdown also enhanced phagocytosis and lipid transport by macrophages, and increased the expression of autophagy-related molecules in macrophages, which improved the autophagy level, promoted apoptotic cell degradation, and maintained intracellular environment homeostasis.

CONCLUSIONS

These results indicate a correlation between INOS expression and macrophage function in NAFLD.

Association between nonalcoholic fatty liver disease and type 2 diabetes: A bidirectional two-sample mendelian randomization study

OBJECTIVE

The aim of this study was to explore the mutually causal relationship between NAFLD and type 2 diabetes.

METHODS

Based on the data obtained from GWAS, this study employed bidirectional two-sample MR analysis to investigate the causal relationship between NAFLD and type 2 diabetes, and also examined the causal relationship between liver fat accumulation and type 2 diabetes as well as the relationship between NAFLD and FPG, IR.

RESULTS

In MR analysis of NAFLD and type 2 diabetes, when NAFLD as an exposure and type 2 diabetes as a result, the OR (95 % CI) was 1.10890 (1.00135-1.22801); in the reverse analysis, the OR value was not statistically significant. In MR analysis of NAFLD, FPG and IR, there was no statistical significance in both directions. In MR analysis of liver fat accumulation and type 2 diabetes, when liver fat as an exposure and type 2 diabetes as a result, the OR (95 % CI) was 1.17516 (1.02054-1.35321); in the reverse analysis, the OR value (95 % CI) was 1.06283 (1.02879-1.09799).

CONCLUSION

There is a unidirectional causal relationship between NAFLD and type 2 diabetes. Furthermore, a bidirectional causal relationship exists between liver fat accumulation and type 2 diabetes.

Obeticholic acid treatment of mice to promote fertilization and reproduction

Obeticholic acid (OCA), a farnesoid X receptor (FXR) agonist, has been demonstrated to ameliorate the histopathological characteristics of liver damage. Nonetheless, the systemic safety profile of OCA with regard to reproduction and development remains poorly understood. In the present study, we conducted a dose-response experiment by administering OCA at doses of 5 mg/kg, 10 mg/kg, or 20 mg/kg through tube feeding to investigate its effect on reproductive development and fertilization rate in both male and female mice. Furthermore, we evaluated the levels of protein and mitochondrial function in the placenta through western blot, qPCR, and scanning electron microscopy. The results showed that 10 mg/kg and 20 mg/kg OCA doses significantly reduced the rate of placental implantation (P < 0.05). Also, OCA increased maternal body weight. In addition, OCA increased levels of FXR and TGR5 and produced changes in oxidative stress levels (P < 0.05). Mitochondrial activity result found that 10 mg/kg and 20 mg/kg of OCA significantly reduced the mitophagy autosomes/nucleus compared with the normal control group (P < 0.05). What is more, there was no significant difference in sperm count after OCA intervention in either C57BL/10 mice or BALB/c mice. Overall, we demonstrated that OCA treatment protected against placental implantation by suppressing placental oxidative stress and mitochondrial activity.

Naringin ameliorates liver fibrosis in zebrafish by modulating IDO1-mediated lipid metabolism and inflammatory infiltration

Liver fibrosis (LF) is an important reparative process in response to acute or chronic hepatic injury, which has the potential to advance towards cirrhosis and hepatocellular carcinoma. Dietary naringin consumption contributes to protection against LF in animal studies, while the exact protective mechanism of naringin remains unclear. This study aimed to investigate the molecular mechanisms behind the potential protective effect of naringin against TAA-induced LF in zebrafish. In this study, we utilized zebrafish to create the LF model and investigate the therapeutic mechanism of naringin. Firstly, we evaluated the changes in hepatic fibrosis and lipid accumulation in the liver following naringin treatment with oil red O, Nile red, and Sirius red and immunohistochemistry. In addition, we employed an ROS probe to directly measure oxidative stress and monitor inflammatory cell migration in a zebrafish transgenic line. Morpholino was used in the knockdown of IDO1 in order to verify its vital role in LF. Our findings demonstrated that naringin exhibited anti-inflammatory and anti-fibrotic action in conjunction with a reversal in lipid accumulation, oxidative stress and suppression of macrophage infiltration and activation of hepatic stellate cells. Furthermore, the results showed that the antifibrotic effect of naringin was removed upon IDO1 knockdown, proving that naringin exerts a protective effect by regulating IDO1. Naringin demonstrates remarkable protective effects against LF, effectively counteracting inflammation and hepatic steatosis in zebrafish liver. These findings suggest that naringin may function as an effective IDO1 inhibitor, holding the potential for clinical translation as a therapeutic agent for the treatment of LF.

Dietary and lifestyle oxidative balance scores are independently and jointly associated with nonalcoholic fatty liver disease: a 20 years nationally representative cross-sectional study

Background

Oxidative stress is an important contributor to the progression of nonalcoholic fatty liver disease (NAFLD), but whether dietary and lifestyle pro- and antioxidants may have combined or independent effects on NAFLD, and advanced liver fibrosis (AHF) remains unclear. We aimed to elucidate the relationship between a well-established oxidative balance score (OBS) and NAFLD/AHF.

Methods

This was a cross-sectional study. We included adult participants with complete data from the National Health and Nutrition Examination Survey 1999-2018. Survey-weighted adjusted multivariate regression analyses were used to examine the association of all OBS with NAFLD/AHF. A combination of restricted cubic splines, mediation analysis, stratified analysis, and sensitivity analysis were used to further elucidate these associations.

Results

We included 6,341 eligible adult participants with prevalence of NAFLD and AHF of 30.2 and 13.9%, respectively. In the fully adjusted model, the highest quartile of OBS, dietary OBS, and lifestyle OBS were associated with 65, 55, and 77% reduced risk of NAFLD, respectively, compared with the reference population, respectively. However, all OBS were not associated with the risk of AHF. All OBS were nonlinearly associated with risk of NAFLD and had a more pronounced reduced risk for OBS, dietary OBS, and lifestyle OBS after exceeding 26, 21, and 5 points, respectively. OBS may exert a protective effect indirectly through inflammation, oxidative stress, and glycolipid metabolism markers. Stratification and sensitivity analyses demonstrate the robustness of our findings.

Conclusion

All OBS were nonlinearly and negatively associated with NAFLD risk. These effects may exert indirectly through inflammation, oxidative stress, and glycolipid metabolism markers.

Critical appraisal of metabolic dysfunction-associated steatotic liver disease: Implication of Janus-faced modernity

The existing term non-alcoholic fatty liver disease (NAFLD) has raised substantial concerns due to its inherent disadvantages of using exclusionary diagnostic criteria and the stigmatizing word 'fatty.' Three pan-national liver associations set out to explore a new nomenclature to replace both NAFLD and its suggested alternative, metabolic (dysfunction)-associated fatty liver disease (MAFLD). They surveyed if a change in nomenclature and/or definition is favored and which nomenclature best communicates disease characteristics and increases awareness. In lieu of NAFLD/MAFLD, metabolic dysfunction-associated steatotic liver disease (MASLD) has been chosen, and an umbrella term, steatotic liver disease (SLD), encompassing the whole spectrum of liver disease, has been proposed. It has been suggested that cardiometabolic risk factors should be considered when categorizing SLD patients. Furthermore, a new subcategory, MASLD with increased alcohol intake (MetALD), casts light on a neglected group of patients with moderate or more alcohol consumption. The importance of metabolic dysfunction was acknowledged in this new nomenclature, but the precise contribution of metabolic dysfunction and alcohol consumption to the development and progression of SLD remains unclear. Herein, we review hepatologists' and endocrinologists' perspectives on the new nomenclature, along with its possible impact on clinical practice. Although it is premature to predict the settlement of the new nomenclature, this review may help build more evidence for a soft landing of it in the future.

Non-Alcoholic Fatty Liver Disease and Echocardiographic Parameters of Left Ventricular Diastolic Function: A Systematic Review and Meta-Analysis

The cardiovascular implications of non-alcoholic fatty liver disease (NAFLD) have been associated with heart failure with preserved ejection fraction (HFpEF). The purpose of this review was to conduct a bibliographic search regarding the correlation between NAFLD and the echocardiographic parameters of left ventricular diastolic function. A systematic literature search was conducted in PubMed and Embase for original research data reporting on the association of NAFLD with diastolic function markers [E/e', left atrial volume index (LAVi), left ventricular mass index (LVMi)]. Meta-analysis was performed using the meta and dmetar packages in R studio v.1.4.1106, with p < 0.05 values being considered significant. Results are expressed as the standardized mean difference (SMD) for continuous variables and as the odds ratio (OR) for categorical variables, with respective 95% confidence intervals (CI). Heterogeneity between studies was expressed with index Ι2. From the preliminary search, 2619 articles were found from which 31 studies were included in the final statistical analysis. The meta-analysis of 8 studies which reported on the prevalence of diastolic dysfunction showed that it was increased in patients with NAFLD (OR: 2.07, 95% CI 1.24-3.44 with p = 0.01, I2: 80% with p < 0.01). The meta-analysis of 21 studies showed significantly higher E/e' in NAFLD patients (SMD 1.02, 95% CI 0.43-1.61 with p < 0.001, I2: 97% with p < 0.001). Individuals with NAFLD had increased LAVi (SMD: 0.87, 95% CI 0.38-1.37 with p < 0.001, I2: 96% with p < 0.001) and LVMi (SMD: 0.89, 95% CI 0.31-1.48 with p = 0.003, I2: 100% with p < 0.001). To conclude, in the meta-analysis of 31 observational studies, NAFLD patients were found to have affected left ventricular diastolic function, supporting the hypothesis of NAFLD being associated with HFpEF.

Non-alcoholic fatty liver disease: Immunological mechanisms and current treatments

Non-alcoholic fatty liver disease (NAFLD) causes significant global disease burden and is a leading cause of mortality. NAFLD induces a myriad of aberrant changes in hepatocytes at both the cellular and molecular level. Although the disease spectrum of NAFLD is widely recognised, the precise triggers for disease progression are still to be fully elucidated. Furthermore, the propagation to cirrhosis is poorly understood. Whilst some progress in terms of treatment options have been explored, an incomplete understanding of the hepatic cellular and molecular alterations limits their clinical utility. We have therefore reviewed some of the key pathways responsible for the pathogenesis of NAFLD such as innate and adaptative immunity, lipotoxicity and fibrogenesis, and highlighted current trials and treatment options for NAFLD patients.

Non-Alcoholic Fatty Liver Disease, Atherosclerosis, and Cardiovascular Disease in Asia

The prevalence of non-alcoholic fatty liver disease (NAFLD) is estimated to increase to over half of the adult population by 2040 globally. Since the final diagnosis of NAFLD is made by a liver biopsy, several non-invasive approaches have been developed and validated to define NAFLD and evaluate NAFLD-associated diseases. Presently, NAFLD has been identified as an important and independent risk factor for developing several extrahepatic diseases, including atherosclerosis, cardiovascular disease (CVD), diabetes, and dementia. This review discusses current findings of up-to-date literature regarding the effects of NAFLD on the risk of atherosclerosis and CVD in Asia along with potential underlying biological mechanisms and therapeutic approaches to lower the NAFLD-related CVD risk. We further focus on the difference between NAFLD and metabolic dysfunction-associated fatty liver disease (MAFLD) on the risk of CVD and its implication by comparing the risk of NAFLD and MAFLD.

In Vivo and In Vitro Models to Study Liver Fibrosis: Mechanisms and Limitations

Liver fibrosis is a common result of liver injury owing to various kinds of chronic liver diseases. A deeper understanding of the pathophysiology of liver fibrosis and identifying potential therapeutic targets of liver fibrosis is important because liver fibrosis may progress to advanced liver diseases, such as cirrhosis and hepatocellular carcinoma. Despite numerous studies, the underlying mechanisms of liver fibrosis remain unclear. Mechanisms of the development and progression of liver fibrosis differ according to etiologies. Therefore, appropriate liver fibrosis models should be selected according to the purpose of the study and the type of underlying disease. Many in vivo animal and in vitro models have been developed to study liver fibrosis. However, there are no perfect preclinical models for liver fibrosis. In this review, we summarize the current in vivo and in vitro models for studying liver fibrosis and highlight emerging in vitro models, including organoids and liver-on-a-chip models. In addition, we discuss the mechanisms and limitations of each model.

A Combination of an Angiotensin II Receptor and a Neprilysin Inhibitor Attenuates Liver Fibrosis by Preventing Hepatic Stellate Cell Activation

The renin-angiotensin-aldosterone system has gained attention due to its role as a mediator of liver fibrosis and hepatic stellate cell (HSC) activation. Meanwhile, the natriuretic peptide (NP) system, including atrial NP (ANP) and C-type NP (CNP), is a counter-regulatory hormone regulated by neprilysin. Although the combination of an angiotensin receptor and a neprilysin inhibitor (sacubitril/valsartan: SAC/VAL) has shown clinical efficacy in patients with heart failure, its potential effects on hepatic fibrosis have not been clarified. This study assessed the effects of SAC/VAL in carbon tetrachloride (CCl₄)-induced murine liver fibrosis as well as the in vitro phenotypes of HSCs. Treatment with SAC and VAL markedly attenuated CCl₄-induced liver fibrosis while reducing α-SMA⁺-HSC expansion and decreasing hepatic hydroxyproline and mRNA levels of pro-fibrogenic markers. Treatment with SAC increased plasma ANP and CNP levels in CCl₄-treated mice, and ANP effectively suppressed cell proliferation and TGF-β-stimulated MMP2 and TIMP2 expression in LX-2 cells by activating guanylate cyclase-A/cGMP/protein kinase G signaling. Meanwhile, CNP did not affect the pro-fibrogenic activity of LX-2 cells. Moreover, VAL directly inhibited angiotensin II (AT-II)-stimulated cell proliferation and the expression of TIMP1 and CTGF through the blockade of the AT-II type 1 receptor/protein kinase C pathway. Collectively, SAC/VAL may be a novel therapeutic treatment for liver fibrosis.

Noninvasive serum biomarkers for liver fibrosis in NAFLD: current and future

In the last 20 years, noninvasive serum biomarkers to identify liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) have been developed, validated against liver biopsy (the gold standard for determining the presence of liver fibrosis) and made available for clinicians to use to identify ≥F3 liver fibrosis. The aim of this review is firstly to focus on the current use of widely available biomarkers and their performance for identifying ≥F3. Secondly, we discuss whether noninvasive biomarkers have a role in identifying F2, a stage of fibrosis that is now known to be a risk factor for cirrhosis and overall mortality. We also consider whether machine learning algorithms offer a better alternative for identifying individuals with ≥F2 fibrosis. Thirdly, we summarise the utility of noninvasive serum biomarkers for predicting liver related outcomes (e.g., ascites and hepatocellular carcinoma) and non-liver related outcomes (e.g., cardiovascular-related mortality and extra hepatic cancers). Finally, we examine whether serial measurement of biomarkers can be used to monitor liver disease, and whether the use of noninvasive biomarkers in drug trials for non-alcoholic steatohepatitis can accurately, compared to liver histology, monitor liver fibrosis progression/regression. We conclude by offering our perspective on the future of serum biomarkers for the detection and monitoring of liver fibrosis in NAFLD.

Neuregulin 4 as a novel adipokine in energy metabolism

Adipose tissue has been shown to play a key role in energy metabolism and it has been shown to regulate metabolic homeostasis through the secretion of adipokines. Neuregulin 4 (Nrg4), a novel adipokine secreted mainly by brown adipose tissue (BAT), has recently been characterized as having an important effect on the regulation of energy homeostasis and glucolipid metabolism. Nrg4 can modulate BAT-related thermogenesis by increasing sympathetic innervation of adipose tissue and therefore has potential metabolic benefits. Nrg4 improves metabolic dysregulation in various metabolic diseases such as insulin resistance, obesity, non-alcoholic fatty liver disease, and diabetes through several mechanisms such as anti-inflammation, autophagy regulation, pro-angiogenesis, and lipid metabolism normalization. However, inconsistent findings are found regarding the effects of Nrg4 on metabolic diseases in clinical settings, and this heterogeneity needs to be further clarified by future studies. The potential metabolic protective effect of Nrg4 suggests that it may be a promising endocrine therapeutic target.

Immunotherapy for NAFLD and NAFLD-related hepatocellular carcinoma

The progression of non-alcoholic fatty liver disease (NAFLD), the most common liver disease, leads to non-alcoholic steatohepatitis and hepatocellular carcinoma. Despite the increasing incidence and prevalence of NAFLD, its therapeutic and preventive strategies to lower the disease burden is limited. In recent years, immunotherapy, including anti-programmed cell death 1/programmed cell death 1 ligand 1 treatment, has emerged as a potential approach to reach satisfactory modulation for the progression of NAFLD and treatment of NAFLD-related hepatocellular carcinoma. However, the effectiveness of immunotherapy against NAFLD and NAFLD-related hepatocellular carcinoma is in the early phase and it is yet not advanced. In addition, conflicting results are being reported regarding the prognosis of patients with NAFLD-related hepatocellular carcinoma and high expression of programmed cell death 1/programmed cell death 1 ligand 1. Herein, this review will discuss and elucidate the attempts and underlying mechanisms of immunotherapy against NAFLD and NAFLD-related hepatocellular carcinoma.