Shared Mechanisms between Cardiovascular Disease and NAFLD

Metabolic dysfunction-associated steatotic liver disease in adults

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the umbrella term that comprises metabolic dysfunction-associated steatotic liver, or isolated hepatic steatosis, through to metabolic dysfunction-associated steatohepatitis, the progressive necroinflammatory disease form that can progress to fibrosis, cirrhosis and hepatocellular carcinoma. MASLD is estimated to affect more than one-third of adults worldwide. MASLD is closely associated with insulin resistance, obesity, gut microbial dysbiosis and genetic risk factors. The obesity epidemic and the growing prevalence of type 2 diabetes mellitus greatly contribute to the increasing burden of MASLD. The treatment and prevention of major metabolic comorbidities such as type 2 diabetes mellitus and obesity will probably slow the growth of MASLD. In 2023, the field decided on a new nomenclature and agreed on a set of research and action priorities, and in 2024, the US FDA approved the first drug, resmetirom, for the treatment of non-cirrhotic metabolic dysfunction-associated steatohepatitis with moderate to advanced fibrosis. Reliable, validated biomarkers that can replace histology for patient selection and primary end points in MASH trials will greatly accelerate the drug development process. Additionally, noninvasive tests that can reliably determine treatment response or predict response to therapy are warranted. Sustained efforts are required to combat the burden of MASLD by tackling metabolic risk factors, improving risk stratification and linkage to care, and increasing access to therapeutic agents and non-pharmaceutical interventions.

Higher risk of carotid plaque among lean individuals with non-alcoholic fatty liver disease: A retrospective study

BACKGROUND

Lean individual with non-alcoholic fatty liver disease (L-NAFLD) is a prominent area of research, yet its pathogenesis and association with other diseases such as atherosclerotic cardiovascular disease remain uncertain.

OBJECT

A retrospective study, investigate the association between non-alcoholic fatty liver disease (NAFLD) and carotid plaque (CP) in lean [body mass index (BMI) <24Kg/m2] and non-lean (BMI≥24Kg/m2) populations, as well as identify the related influence factors.

METHOD

3,587 participants were eligible and categorized into 4 groups based on the presence with CP and BMI, binary logistic regression analysis was utilized alongside other statistical methods.

RESULTS

L-NAFLD participants had a 1.395-fold higher risk of CP compared to lean individuals without NAFLD. Age, gender, systolic blood pressure, low-density lipoprotein cholesterol, fasting blood glucose, and Fibrosis-4 index (FIB-4) were identified as independent risk factors with cutoff values lower than the normal upper limits. However, this association was not observed among non-lean participants, regardless of confounding factors adjustment. Moreover, the impact of FIB-4 on the association of NAFLD and CP was more significant in lean CP participants (OR = 1.360 for 1.30 ~ 2.67, and OR = 2.002 for >2.67~<3.48) than in non-lean CP ones.

CONCLUSION

The L-NAFLD population had a higher risk of CP, while lean CP individuals experienced more severe liver fibrosis. Implementing stricter management of risk factors may improve the health status of high-risk populations.

The effect of gut microbiome-targeted therapies in nonalcoholic fatty liver disease: a systematic review and network meta-analysis

Background

The incidence of NAFLD is increasing. Preclinical evidences indicate that modulation of the gut microbiome could be a promising target in nonalcoholic fatty liver disease.

Method

A systematic review and network meta-analysis was conducted to compare the effect of probiotics, synbiotics, prebiotics, fecal microbiota transplant, and antibiotics on the liver-enzyme, metabolic effects and liver-specific in patients with NAFLD. The randomized controlled trails (RCTs), limited to English language were searched from database such as Pubmed, Embase, Web of science and Cochrane Library from inception to November 2024. Review Manager 5.3 was used to to draw a Cochrane bias risk. Inconsistency test and publication-bias were assessed by Stata 14.0. Random effect model was used to assemble direct and indirect evidences. The effects of the intervention were presented as mean differences with 95% confidence interval.

Results

A total of 1921 patients from 37 RCTs were eventually included in our study. 23 RCTs evaluated probiotics, 10 RCTs evaluated synbiotics, 4 RCTs evaluated prebiotics, 3 RCTs evaluated FMT and one RCT evaluated antibiotics. Probiotics and synbiotics were associated with a significantly reduction in alanine aminotransferase [ALT, (MD: -5.09; 95%CI: -9.79, -0.39), (MD: -7.38, 95CI%: -11.94, -2.82)] and liver stiffness measurement by elastograph [LSM, (MD: -0.37;95%CI: -0.49, -0.25), (MD: -1.00;95%CI: -1.59, -0.41)]. In addition to, synbiotics was superior to probiotics in reducing LSM. Synbiotics was associated with a significant reduction of Controlled Attenuation Parameter [CAP, (MD: -39.34; 95%CI: -74.73, -3.95)]. Both probiotics and synbiotics were associated with a significant reduction of aspartate transaminase [AST, (MD: -7.81; 95%CI: -15.49, -0.12), (MD: -13.32; 95%CI: -23, -3.64)]. Probiotics and Allogenic FMT was associated with a significant reduction of Homeostatic Model Assessment for Insulin Resistance [HOMA-IR, (MD: -0.7, 95%CI: -1.26, -0.15), (MD: -1.8, 95%CI: -3.53, - 0.07)]. Probiotics was associated with a significant reduction of body mass index [BMI, MD: -1.84, 95%CI: -3.35, -0.33].

Conclusion

The supplement of synbiotics and probiotics maybe a promising way to improve liver-enzyme, LSM, and steatosis in patients with NAFLD. More randomized controlled trials are needed to determine the efficacy of FMT and antibiotics on NAFLD. And the incidence of adverse events of MTTs should be further explored.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, CRD42023450093.

Association Between Noninvasive Liver Fibrosis Scores and Heart Failure in a General Population

BACKGROUND

The association between nonalcoholic fatty liver disease and cardiovascular disease is firmly established, yet the association between noninvasive liver fibrosis scores and cardiovascular events remains a topic of uncertainty. Our study aimed to explore the association between liver fibrosis and heart failure.

METHODS AND RESULTS

The data set was from the National Health and Nutrition Examination Survey 2011 to 2018. Advanced hepatic fibrosis risk was assessed through 3 noninvasive liver fibrosis scores: Fibrosis-4 score (FIB-4), the nonalcoholic fatty liver disease fibrosis score (NFS), and the aspartate aminotransferase to platelet ratio index (APRI). We included 19 695 eligible participants. The national prevalence of advanced liver fibrosis risk in the United States was 4.20%, 8.06%, and 0.35% as determined by FIB-4, NFS, and APRI scores, respectively. Weighted logistic regression analysis revealed significant associations between advanced liver fibrosis risk and the prevalence of heart failure (continuous variables, FIB-4: odds ratio [OR], 1.15 [95% CI, 1.07-1.23]; NFS: OR, 1.42 [95% CI, 1.23-1.64]; APRI: OR, 1.44 [95% CI, 1.15-1.81]). When the scores were assessed as categorical variables, the results were still significant (FIB-4 ≥2.67 versus FIB-4 <1.3: OR, 2.18 [95% CI, 1.47-3.24]; NFS ≥0.675 versus NFS <-1.455: OR, 2.53 [95% CI, 1.37-4.68]). Subgroup analysis found that the association between APRI and heart failure was stronger in female patients.

CONCLUSIONS

In the general US population, the prevalence of advanced liver fibrosis risk varied between 0.35% and 8.06% as indicated by noninvasive liver fibrosis scores. FIB-4, NFS, and APRI scores were linked to an elevated prevalence of heart failure.

Efficacy and Safety of GLP-1 Receptor Agonists in Patients With Metabolic Dysfunction-Associated Steatotic Liver Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Metabolic dysfunction-associated steatotic liver disease (MASLD) poses a major global health challenge. glucagon-like peptide-1 receptor agonists (GLP-1RAs) have shown potential therapeutic benefits for MASLD patients, including improvements in liver function, inflammation, and fibrosis. This study aims to systematically review and meta-analyze randomized controlled trials (RCTs) to evaluate the efficacy and safety of GLP-1RAs in MASLD patients, focusing on hepatic outcomes, cardiovascular outcomes, anthropometric measurements, and mortality. Following PRISMA guidelines, a comprehensive database search was conducted to include RCTs assessing GLP-1RAs' effects on MASLD. Quality assessment was conducted using the Revised Cochrane Risk of Bias tool. Our meta-analysis used a random-effects model, calculating standardized mean differences for continuous outcomes to determine the agents' efficacy and safety. Additionally, funnel plots were generated to assess publication bias, ensuring the integrity of our meta-analytical findings. The review included 27 trials, revealing GLP-1RAs significantly improved hepatic function markers (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and liver fat content) and cardiovascular risk factors (fasting blood sugar, HbA1c levels, lipid profiles). Additionally, GLP-1RAs were associated with significant reductions in body weight, BMI, subcutaneous fat, and waist circumference. GLP-1RAs demonstrate a promising therapeutic role in managing MASLD, offering benefits that extend to improving liver function, mitigating cardiovascular risk, and promoting weight loss. Further research is needed to confirm these findings and optimize GLP-1RAs' usage in MASLD treatment.

Systemic impacts of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) on heart, muscle, and kidney related diseases

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most common liver disorder worldwide, with an estimated global prevalence of more than 31%. Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as non-alcoholic steatohepatitis (NASH), is a progressive form of MASLD characterized by hepatic steatosis, inflammation, and fibrosis. This review aims to provide a comprehensive analysis of the extrahepatic manifestations of MASH, focusing on chronic diseases related to the cardiovascular, muscular, and renal systems. A systematic review of published studies and literature was conducted to summarize the findings related to the systemic impacts of MASLD and MASH. The review focused on the association of MASLD and MASH with metabolic comorbidities, cardiovascular mortality, sarcopenia, and chronic kidney disease. Mechanistic insights into the concept of lipotoxic inflammatory "spill over" from the MASH-affected liver were also explored. MASLD and MASH are highly associated (50%-80%) with other metabolic comorbidities such as impaired insulin response, type 2 diabetes, dyslipidemia, hypertriglyceridemia, and hypertension. Furthermore, more than 90% of obese patients with type 2 diabetes have MASH. Data suggest that in middle-aged individuals (especially those aged 45-54), MASLD is an independent risk factor for cardiovascular mortality, sarcopenia, and chronic kidney disease. The concept of lipotoxic inflammatory "spill over" from the MASH-affected liver plays a crucial role in mediating the systemic pathological effects observed. Understanding the multifaceted impact of MASH on the heart, muscle, and kidney is crucial for early detection and risk stratification. This knowledge is also timely for implementing comprehensive disease management strategies addressing multi-organ involvement in MASH pathogenesis.

Taiwan Association for the Study of the Liver-Taiwan Society of Cardiology Taiwan position statement for the management of metabolic dysfunction- associated fatty liver disease and cardiovascular diseases

Metabolic dysfunction-associated fatty liver disease (MAFLD) is an increasingly common liver disease worldwide. MAFLD is diagnosed based on the presence of steatosis on images, histological findings, or serum marker levels as well as the presence of at least one of the three metabolic features: overweight/obesity, type 2 diabetes mellitus, and metabolic risk factors. MAFLD is not only a liver disease but also a factor contributing to or related to cardiovascular diseases (CVD), which is the major etiology responsible for morbidity and mortality in patients with MAFLD. Hence, understanding the association between MAFLD and CVD, surveillance and risk stratification of MAFLD in patients with CVD, and assessment of the current status of MAFLD management are urgent requirements for both hepatologists and cardiologists. This Taiwan position statement reviews the literature and provides suggestions regarding the epidemiology, etiology, risk factors, risk stratification, nonpharmacological interventions, and potential drug treatments of MAFLD, focusing on its association with CVD.

Development and Validation of the Nonalcoholic Fatty Liver Disease Familial Risk Score to Detect Advanced Fibrosis: A Prospective, Multicenter Study

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD)-related fibrosis is heritable, but it is unclear how family history may be used to identify first-degree relatives with advanced fibrosis. We aimed to develop and validate a simple risk score to identify first-degree relatives of probands who have undergone assessment of liver fibrosis who are at higher risk of NAFLD with advanced fibrosis.

METHODS

This prospective, cross-sectional, familial study consisted of a derivation cohort from San Diego, California, and a validation cohort from Helsinki, Finland. This study included consecutive adult probands (n = 242) with NAFLD and advanced fibrosis, NAFLD without advanced fibrosis, and non-NAFLD, with at least 1 of their first-degree relatives. All included probands and first-degree relatives underwent evaluation of liver fibrosis, the majority by magnetic resonance elastography.

RESULTS

A total of 396 first-degree relatives (64% male) were included. The median age and body mass index were 47 years (interquartile range, 32-62 y) and 27.6 kg/m2 (interquartile range, 24.1-32.5 kg/m2), respectively. Age (1 point), type 2 diabetes (1 point), obesity (2 points), and proband with NAFLD and advanced fibrosis (2 points) were predictors of advanced fibrosis among first-degree relatives in the derivation cohort (n = 220) and formed the NAFLD Familial Risk Score. The area under the receiver operator characteristic curve of the NAFLD Familial Risk Score for detecting advanced fibrosis was 0.94 in the validation cohort (n = 176). The NAFLD Familial Risk Score outperformed the Fibrosis-4 index in the validation cohort (area under the receiver operator characteristic curve, 0.94 vs 0.70; P = .02).

CONCLUSIONS

The NAFLD Familial Risk Score is a simple and accurate clinical tool to identify advanced fibrosis in first-degree relatives. These data may have implications for surveillance in NAFLD.

Antifibrotic therapy in nonalcoholic steatohepatitis: time for a human-centric approach

Nonalcoholic steatohepatitis (NASH) might soon become the leading cause of end-stage liver disease and indication for liver transplantation worldwide. Fibrosis severity is the only histological predictor of liver-related morbidity and mortality in NASH identified to date. Moreover, fibrosis regression is associated with improved clinical outcomes. However, despite numerous clinical trials of plausible drug candidates, an approved antifibrotic therapy remains elusive. Increased understanding of NASH susceptibility and pathogenesis, emerging human multiomics profiling, integration of electronic health record data and modern pharmacology techniques hold enormous promise in delivering a paradigm shift in antifibrotic drug development in NASH. There is a strong rationale for drug combinations to boost efficacy, and precision medicine strategies targeting key genetic modifiers of NASH are emerging. In this Perspective, we discuss why antifibrotic effects observed in NASH pharmacotherapy trials have been underwhelming and outline potential approaches to improve the likelihood of future clinical success.

Uncovering the Cardiovascular Threat: A Comprehensive Examination of Liver Fibrosis and Subclinical Atherosclerosis in Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has emerged as a global epidemic intricately linked to the rising tide of obesity and metabolic syndrome. This comprehensive review delves into the complex web of relationships between NAFLD, liver fibrosis, and subclinical atherosclerosis, shedding light on their interplay, shared risk factors, and clinical implications. NAFLD encompasses a spectrum of liver conditions, from the benign non-alcoholic fatty liver (NAFL) to the more severe non-alcoholic steatohepatitis (NASH), characterized by inflammation and hepatocellular injury. Central to the discussion is the insidious development of liver fibrosis, the ominous harbinger of progressive liver damage, cirrhosis, and hepatocellular carcinoma. The increasing prevalence of NAFLD, now affecting a quarter of the global population, poses a significant public health challenge. Its association with obesity, insulin resistance, and metabolic syndrome highlights the multifactorial nature of this disease. However, NAFLD's repercussions extend beyond the liver. This review unveils a potent connection between NAFLD and subclinical atherosclerosis, the early precursor to cardiovascular disease. Individuals with NAFLD face an elevated risk of atherosclerosis, even without traditional cardiovascular risk factors. The intricate link between these two conditions is illuminated through shared pathophysiological pathways, including systemic inflammation, insulin resistance, and dyslipidemia. Understanding the interplay between liver fibrosis and subclinical atherosclerosis has profound clinical implications. Patients with advanced fibrosis or cirrhosis are not only at risk of liver-related complications but also of cardiovascular events. This necessitates a holistic approach to patient care, with lifestyle modifications and pharmacological interventions simultaneously managing both conditions. Physicians must prioritize early detection and collaborate across disciplines to provide comprehensive care. Looking ahead, the future holds promising avenues of research. Emerging areas include genetics and precision medicine, microbiome research, and epigenetics, which may unveil new therapeutic targets. Innovations in diagnostics and therapeutics, such as non-invasive biomarkers and combination therapies, offer hope for more effective management. Long-term outcomes and survivorship research will provide insights into the lasting impact of interventions. In conclusion, this review underscores the imperative of addressing liver fibrosis and atherosclerosis in the context of NAFLD. It is a call to action for healthcare professionals, researchers, and policymakers to work collaboratively, promote early detection, and advance our understanding of these interconnected conditions. By doing so, we can enhance patient outcomes and chart a course toward a healthier future for those grappling with NAFLD and its intricate web of consequences.

Non-alcoholic fatty liver disease and risk of cardiovascular diseases: clinical association, pathophysiological mechanisms, and management

Non-alcoholic fatty liver disease (NAFLD) is a fatty liver disease associated with metabolic dysfunction in genetically susceptible individuals due to over-nutrition and lack of exercise. With the prevalence of obesity, metabolic syndrome, and type 2 diabetes mellitus, NAFLD has become the most common cause of chronic liver disease worldwide. NAFLD shares many risk factors with cardiovascular diseases (CVDs). NAFLD is associated with increased risk of major cardiovascular events and other cardiac complications even after adjustment for traditional cardiovascular risk factors. The primary pathology of NAFLD is within the liver, but the most common cause of deaths in patients with NAFLD is CVDs. This review summarizes the epidemiological evidence for the association between NAFLD and CVD risk and the pathophysiological mechanisms underlying this association. Current treatment strategies for NAFLD and their potential impact on CVD risk are also discussed.

Carbon Dots as Potential Therapeutic Agents for Treating Non-Alcoholic Fatty Liver Disease and Associated Inflammatory Bone Loss

Nonalcoholic fatty liver disease (NAFLD) has emerged as one of the most significant metabolic diseases worldwide and is associated with heightened systemic inflammation, which has been shown to foster the development of extrahepatic complications. So far, there is no definitive, effective, and safe treatment for NAFLD. Although antidiabetic agents show potential for treating NAFLD, their efficacy is significantly limited by inadequate liver accumulation at safe doses and unwanted side effects. Herein, we demonstrate that pharmacologically active carbon dots (MCDs) derived from metformin can selectively accumulate in the liver and ameliorate NAFLD by activating hepatic PPARα expression while maintaining an excellent biosafety. Interestingly, MCDs can also improve the function of extrahepatic organs and tissues, such as alleviating alveolar inflammatory bone loss, in the process of treating NAFLD. This study proposes a feasible and safe strategy for designing pharmacologically active MCDs to target the liver, which regulates lipid metabolism and systemic inflammation, thereby treating NAFLD and its related extrahepatic complications.

Clinical utility of liver fat quantification for determining cardiovascular disease risk among patients with type 2 diabetes

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are independent risk factors for cardiovascular disease (CVD).

AIMS

To examine the clinical utility of liver fat quantification for determining CVD risk among a well-phenotyped cohort of patients with T2DM.

METHODS

This was a cross-sectional analysis of a prospective cohort of adults aged ≥50 with T2DM. Liver fat was quantified with magnetic resonance imaging proton-density-fat-fraction (MRI-PDFF), an advanced imaging-based biomarker. Patients were stratified into a higher liver fat group (MRI-PDFF ≥ 14.6%), and a lower liver fat group (MRI-PDFF < 14.6%). The co-primary outcomes were CVD risk determined by Framingham and Atherosclerotic Cardiovascular Disease (ASCVD) risk scores. High CVD risk was defined by risk scores ≥20%.

RESULTS

Of the 391 adults (66% female) in this study, the mean (±SD) age was 64 (±8) years and BMI 30.8 (±5.2) kg/m2 , respectively. In multivariable analysis, adjusted for age, gender, race, and BMI, patients in the higher liver fat group had higher CVD risk [OR = 4.04 (95% CI: 2.07-7.88, p < 0.0001)] and ASCVD risk score [OR = 2.85 (95% CI: 1.19-6.83, p = 0.018)], respectively.

CONCLUSION

Higher liver fat content increases CVD risk independently of age, gender, ethnicity and BMI. These findings raise the question whether liver fat quantification should be incorporated into risk calculators to further stratify those with higher CVD risk.

Clinical and histologic factors associated with discordance between steatosis grade derived from histology vs. MRI-PDFF in NAFLD

BACKGROUND

Magnetic resonance imaging-proton density fat fraction (MRI-PDFF) is an excellent biomarker for the non-invasive quantification of hepatic steatosis.

AIM

To examine clinical and histologic factors associated with discordance between steatosis grade determined by histology and MRI-PDFF in patients with non-alcoholic fatty liver disease (NAFLD) METHODS: We included 728 patients with biopsy-proven NAFLD from UC San Diego (n = 414) and Yokohama City University (n = 314) who underwent MRI-PDFF and liver biopsy. Patients were stratified by steatosis, and matched with MRI-PDFF cut-points for each steatosis grade: 0 (MRI-PDFF < 6.4%), 1 (MRI-PDFF: 6.4%-17.4%), 2 (MRI-PDFF: 17.4%-22.1%), 3 (MRI-PDFF ≥ 22.1%). Primary outcome was major discordance defined as ≥2 steatosis grade difference determined by histology and MRI-PDFF.

RESULTS

Mean (±SD) age and BMI were 55.3 (±13.8) years and 29.9 (±4.9) kg/m2 , respectively. The distributions of histology and MRI-PDFF-determined steatosis were 5.5% grade 0 (n = 40), 44.8% 1 (n = 326, 44.8%), 33.9% 2 (n = 247), and 15.8% 3 (n = 115) vs. 23.5% grade 0 (n = 171), 49.7% 1 (n = 362), 12.9% 2 (n = 94), and 13.9% 3 (n = 101). Major discordance rate was 6.6% (n = 48). Most cases with major discordance had greater histology-determined steatosis grade (n = 40, 88.3%), higher serum AST and liver stiffness, and greater likelihood of fibrosis ≥2, ballooning ≥1 and lobular inflammation ≥2 (all p < 0.05).

CONCLUSION

Histology overestimates steatosis grade compared to MRI-PDFF. Patients with advanced NASH are likely to be upgraded on steatosis grade by histology. These data have important implications for steatosis estimation and reporting on histology in clinical practice and trials, especially in patients with stage 2 fibrosis.

Global epidemiology of cirrhosis - aetiology, trends and predictions

Cirrhosis is an important cause of morbidity and mortality in people with chronic liver disease worldwide. In 2019, cirrhosis was associated with 2.4% of global deaths. Owing to the rising prevalence of obesity and increased alcohol consumption on the one hand, and improvements in the management of hepatitis B virus and hepatitis C virus infections on the other, the epidemiology and burden of cirrhosis are changing. In this Review, we highlight global trends in the epidemiology of cirrhosis, discuss the contributions of various aetiologies of liver disease, examine projections for the burden of cirrhosis, and suggest future directions to tackle this condition. Although viral hepatitis remains the leading cause of cirrhosis worldwide, the prevalence of non-alcoholic fatty liver disease (NAFLD) and alcohol-associated cirrhosis are rising in several regions of the world. The global number of deaths from cirrhosis increased between 2012 and 2017, but age-standardized death rates (ASDRs) declined. However, the ASDR for NAFLD-associated cirrhosis increased over this period, whereas ASDRs for other aetiologies of cirrhosis declined. The number of deaths from cirrhosis is projected to increase in the next decade. For these reasons, greater efforts are required to facilitate primary prevention, early detection and treatment of liver disease, and to improve access to care.

Insight into the Inter-Organ Crosstalk and Prognostic Role of Liver-Derived MicroRNAs in Metabolic Disease Progression

Dysfunctional hepatic metabolism has been linked to numerous diseases, including non-alcoholic fatty liver disease, the most common chronic liver disorder worldwide, which can progress to hepatic fibrosis, and is closely associated with insulin resistance and cardiovascular diseases. In addition, the liver secretes a wide array of metabolites, biomolecules, and microRNAs (miRNAs) and many of these secreted factors exert significant effects on metabolic processes both in the liver and in peripheral tissues. In this review, we summarize the involvement of liver-derived miRNAs in biological processes with an emphasis on delineating the communication between the liver and other tissues associated with metabolic disease progression. Furthermore, the review identifies the primary molecular targets by which miRNAs act. These consolidated findings from numerous studies provide insight into the underlying mechanism of various metabolic disease progression and suggest the possibility of using circulatory miRNAs as prognostic predictors and therapeutic targets for improving clinical intervention strategies.

Gut-Microbiota Dysbiosis in Stroke-Prone Spontaneously Hypertensive Rats with Diet-Induced Steatohepatitis

Metabolic-dysfunction-associated fatty-liver disease (MAFLD) is the principal worldwide cause of liver disease. Individuals with nonalcoholic steatohepatitis (NASH) have a higher prevalence of small-intestinal bacterial overgrowth (SIBO). We examined gut-microbiota isolated from 12-week-old stroke-prone spontaneously hypertensive-5 rats (SHRSP5) fed on a normal diet (ND) or a high-fat- and high-cholesterol-containing diet (HFCD) and clarified the differences between their gut-microbiota. We observed that the Firmicute/Bacteroidetes (F/B) ratio in both the small intestines and the feces of the SHRSP5 rats fed HFCD increased compared to that of the SHRSP5 rats fed ND. Notably, the quantities of the 16S rRNA genes in small intestines of the SHRSP5 rats fed HFCD were significantly lower than those of the SHRSP5 rats fed ND. As in SIBO syndrome, the SHRSP5 rats fed HFCD presented with diarrhea and body-weight loss with abnormal types of bacteria in the small intestine, although the number of bacteria in the small intestine did not increase. The microbiota of the feces in the SHRSP5 rats fed HFCD was different from those in the SHRP5 rats fed ND. In conclusion, there is an association between MAFLD and gut-microbiota alteration. Gut-microbiota alteration may be a therapeutic target for MAFLD.