Persistent Nonalcoholic Fatty Liver Disease Increases Risk for Carotid Atherosclerosis

NAFLD and increased risk of cardiovascular disease: clinical associations, pathophysiological mechanisms and pharmacological implications

Non-alcoholic fatty liver disease (NAFLD) is a public health problem, affecting up to a third of the world's adult population. Several cohort studies have consistently documented that NAFLD (especially in its more advanced forms) is associated with a higher risk of all-cause mortality and that the leading causes of death among patients with NAFLD are cardiovascular diseases (CVDs), followed by extrahepatic malignancies and liver-related complications. A growing body of evidence also indicates that NAFLD is strongly associated with an increased risk of major CVD events and other cardiac complications (ie, cardiomyopathy, cardiac valvular calcification and cardiac arrhythmias), independently of traditional cardiovascular risk factors. This narrative review provides an overview of the literature on: (1) the evidence for an association between NAFLD and increased risk of cardiovascular, cardiac and arrhythmic complications, (2) the putative pathophysiological mechanisms linking NAFLD to CVD and other cardiac complications and (3) the current pharmacological treatments for NAFLD that might also benefit or adversely affect risk of CVD.

Non-alcoholic steatohepatitis and progression of carotid atherosclerosis in patients with type 2 diabetes: a Korean cohort study

BACKGROUND

There is increasing concern regarding cardiovascular risk in individuals with non-alcoholic fatty liver disease. This study was conducted to evaluate whether hepatic steatosis with or without fibrosis is associated with the progression of carotid atherosclerosis in patients with type 2 diabetes.

METHODS

From a longitudinal cohort, we enrolled 1120 patients with type 2 diabetes who underwent repeated carotid artery ultrasonography every 1-2 years. Ultrasonographic findings at baseline and after 6-8 years were compared. Presence of hepatic steatosis was mainly assessed by abdominal ultrasonography; patients with hepatic steatosis were further evaluated for hepatic fibrosis according to fibrosis-4 index. We investigated the association between liver status and atherosclerosis progression.

RESULTS

Of 1120 patients, 636 (56.8%) were classified as having hepatic steatosis at baseline. After 6-8 years, 431 (38.5%) showed atherosclerosis progression. Hepatic steatosis was significantly associated with atherosclerosis progression (adjusted odds ratio[AOR]: 1.370, 95% CI 1.025-1.832; p < 0.05). Among patients with hepatic steatosis, only individuals with fibrosis showed significant association with atherosclerosis progression (AOR: 1.615, 95% CI 1.005-2.598; p < 0.05). The association between hepatic fibrosis and atherosclerosis progression was significant in all metabolic subgroups regardless of age, body mass index, presence of metabolic syndrome, or insulin sensitivity (all p < 0.05). Furthermore, subjects with hepatic steatosis & fibrosis and ≥ 4 components of metabolic syndrome criteria showed markedly increased risk of atherosclerosis progression (AOR: 2.430, 95% CI 1.087-5.458; p < 0.05).

CONCLUSIONS

Hepatic steatosis with fibrosis is independently associated with the progression of carotid atherosclerosis in patients with type 2 diabetes.

Non-alcoholic fatty liver disease and the incidence of myocardial infarction: A cohort study

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is a multisystem disease associated with an increased risk of cardiovascular disease (CVD), diabetes, and chronic kidney disease. Indeed, CVD is the most common cause of death in NAFLD patients. This study aimed to evaluate the association between NAFLD and the risk of incident myocardial infarction.

METHODS

This is a retrospective cohort study involving 111 492 adults over 40 years old without history of CVD, liver disease, or cancer at baseline who participated in a regular health screening exam between 2003 and 2013. Fatty liver was diagnosed by ultrasonography.

RESULTS

During 725 706.9 person-years of follow-up, 183 participants developed myocardial infarction (incidence rate 0.3 cases per 1000 person-years). The age, sex, and year of visit-adjusted hazard ratio (HR) for incident myocardial infarction comparing participants with NAFLD with those without it was 2.14 (95% confidence interval 1.59, 2.89). This association remained significant in fully adjusted models (HR 1.54; 95% confidence interval 1.11, 2.14). Compared with participants without NAFLD, in participants with low NAFLD fibrosis score (NFS) (< -1.455) and with intermediate-to-high NFS (≥ -1.455), the fully adjusted HRs for incident myocardial infarction were 1.70 (1.22, 2.36) and 1.88 (1.24, 2.87), respectively.

CONCLUSION

In this large cohort study, NAFLD was associated with an increased incidence of myocardial infarction independently of established risk factors. In addition, this association was similar in participants with and without evidence of more advanced NAFLD as indicated by the NFS. NAFLD patients may need to be carefully monitored and managed early to prevent myocardial infarction.

Noninvasive Serum Fibrosis Markers are Associated with Coronary Artery Calcification in Patients with Nonalcoholic Fatty Liver Disease

Background/Aims

Advanced hepatic fibrosis is associated with cardiovascular disease (CVD) in patients with nonalcoholic fatty liver disease (NAFLD). We investigated the association between noninvasive serum fibrosis markers and the coronary artery calcium score (CACS) in subjects with NAFLD.

Methods

We analyzed 665 NAFLD subjects without chronic liver disease or heart disease between 2011 and 2015. The noninvasive fibrosis markers that were used to evaluate the severity of hepatic fibrosis included the NAFLD fibrosis score (NFS), fibrosis-4 (FIB-4) score, Forn's index, and the aspartate aminotransferase to platelet ratio index (APRI).

Results

The areas under the receiver operating characteristics curves for the NFS, FIB-4 score, Forn's index and APRI for predicting CACS >100 were 0.689, 0.683, 0.659, and 0.595, respectively. According to the multivariate analysis, older age, increased body mass index (BMI), and decreased estimated glomerular filtration rate (eGFR) were significant factors associated with CACS >100. The NFS, FIB-4 score and APRI were significantly associated with CACS >100 after adjusting for age and gender (p=0.006, p=0.012, and p=0.012, respectively) and after adjusting for age, gender, BMI and eGFR (p=0.013, p=0.022, and p=0.027, respectively). Scores integrating noninvasive fibrosis markers and other risk factors improved the predictive accuracy.

Conclusions

The NFS and FIB-4 score were associated with coronary atherosclerosis in subjects with NAFLD. Furthermore, scores integrating these noninvasive scores and risk factors for CVD showed good discriminatory power in predicting CACS >100. Therefore, noninvasive serum fibrosis markers may be useful tools for identifying NAFLD subjects at a high risk for CVD.

Assessment of Genetic Aspects of Non-alcoholic Fatty Liver and Premature Cardiovascular Events

Recent evidence has demonstrated a strong interplay and multifaceted relationship between non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD). CVD is the major cause of death in patients with NAFLD. NAFLD also has strong associations with diabetes and metabolic syndrome. In this comprehensive review, we aimed to overview the primary environmental and genetic risk factors of NAFLD, and CVD and also focus on the genetic aspects of these two disorders. NAFLD and CVD are both heterogeneous diseases with common genetic and molecular pathways. We have searched for the latest published articles regarding this matter and tried to provide an overview of recent insights into the genetic aspects of NAFLD and CVD. The common genetic and molecular pathways involved in NAFLD and CVD are insulin resistance (IR), subclinical inflammation, oxidative stress, and atherogenic dyslipidemia. According to an investigation, the exact associations between genomic characteristics of NAFLD and CVD and casual relationships are not fully determined. Different gene polymorphisms have been identified as the genetic components of the NAFLDCVD association. Some of the most documented ones of these gene polymorphisms are patatin-like phospholipase domain-containing protein 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13), adiponectin-encoding gene (ADIPOQ), apolipoprotein C3 (APOC3), peroxisome proliferator-activated receptors (PPAR), leptin receptor (LEPR), sterol regulatory element-binding proteins (SREBP), tumor necrosis factor-alpha (TNF-α), microsomal triglyceride transfer protein (MTTP), manganese superoxide dismutase (MnSOD), membrane-bound O-acyltransferase domain-containing 7 (MBOAT7), and mutation in DYRK1B that substitutes cysteine for arginine at position 102 in kinase-like domain. Further cohort studies with a significant sample size using advanced genomic assessments and next-generation sequencing techniques are needed to shed more light on genetic associations between NAFLD and CVD.

Non-alcoholic Fatty Liver Disease: Growing Burden, Adverse Outcomes and Associations

Nonalcoholic fatty liver disease (NAFLD) is a systemic disorder with a complex multifactorial pathogenesis and heterogenous clinical manifestations. NAFLD, once believed to be an innocuous condition, has now become the most common cause of chronic liver disease in many countries worldwide. NAFLD is already highly prevalent in the general population, and owing to a rising incidence of obesity and diabetes mellitus, the incidence of NAFLD and its impact on global healthcare are expected to increase in the future. A subset of patients with NAFLD develops progressive liver disease leading to cirrhosis, hepatocellular carcinoma, and liver failure. NAFLD has emerged as one of the leading causes of cirrhosis and hepatocellular carcinoma in recent years. Moreover, HCC can occur in NAFLD even in absence of cirrhosis. Compared with the general population, NAFLD increases the risk of liver-related, cardiovascular and all-cause mortality. NAFLD is bidirectionally associated with metabolic syndrome. NAFLD increases the risk and contributes to aggravation of the pathophysiology of atherosclerosis, cardiovascular diseases, diabetes mellitus, and chronic kidney disease. In addition, NAFLD is linked to colorectal polyps, polycystic ovarian syndrome, osteoporosis, obstructive sleep apnea, stroke, and various extrahepatic malignancies. Extended resection of steatotic liver is associated with increased risk of liver failure and mortality. There is an increasing trend of NAFLD-related cirrhosis requiring liver transplantation, and the recurrence of NAFLD in such patients is almost universal. This review discusses the growing burden of NAFLD, its outcomes, and adverse associations with various diseases.

Nonalcoholic Fatty Liver Disease Pandemic Fuels the Upsurge in Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain a leading cause of death worldwide. Among the major risk factors for CVD, obesity and diabetes mellitus have received considerable attention in terms of public policy and awareness. However, the emerging prevalence of nonalcoholic fatty liver disease (NAFLD), as the most common liver and metabolic disease and a cause of CVD, has been largely overlooked. Currently, the number of individuals with NAFLD is greater than the total number of individuals with diabetes mellitus and obesity. Epidemiological studies have established a strong correlation between NAFLD and an increased risk of CVD and CVD-associated events. Although debate continues over the causal relationship between NAFLD and CVD, many mechanistic and longitudinal studies have indicated that NAFLD is one of the major driving forces for CVD and should be recognized as an independent risk factor for CVD apart from other metabolic disorders. In this review, we summarize the clinical evidence that supports NAFLD as a risk factor for CVD epidemics and discuss major mechanistic insights regarding the acceleration of CVD in the setting of NAFLD. Finally, we address the potential treatments for NAFLD and their potential impact on CVD.

Nonalcoholic Fatty Liver Disease and the Heart: JACC State-of-the-Art Review

Nonalcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD) are both manifestations of end-organ damage of the metabolic syndrome. Through multiple pathophysiological mechanisms, CVD and NAFLD are associated with each other. Systemic inflammation, endothelial dysfunction, hepatic insulin resistance, oxidative stress, and altered lipid metabolism are some of the mechanisms by which NAFLD increases the risk of CVD. Patients with NAFLD develop increased atherosclerosis, cardiomyopathy, and arrhythmia, which clinically result in cardiovascular morbidity and mortality. Defining the mechanisms linking these 2 diseases offers the opportunity to further develop targeted therapies. The aim of this comprehensive review is to examine the association between CVD and NAFLD and discuss the overlapping management approaches.

Effect of weight change and lifestyle modifications on the development or remission of nonalcoholic fatty liver disease: sex-specific analysis

The effects of changes in various lifestyle habits on nonalcoholic fatty liver disease (NAFLD) have not been well elucidated. We aimed to clarify how weight change and lifestyle modifications were associated with the development or remission of NAFLD. In this longitudinal cohort study, we reviewed the periodic health checkup data of 1,421 subjects with no causes of liver disease besides NAFLD who had received at least two health checkups between 2009 and 2018. The prevalence of NAFLD at baseline was 34.1% (484/1,421). During follow-up period (4.6 ± 2.8 years), 104 subjects developed NAFLD and 127 subjects demonstrated NAFLD remission. The frequency of NAFLD development or that of NAFLD remission significantly increased as the larger weight gain or weight loss was, respectively (both, p < 0.001). Approximately 40% of the subjects who maintained ≥ 1%/year weight loss achieved NAFLD remission. By multivariate analysis, quitting smoking were independently associated with NAFLD development (adjusted odds ratio [AOR], 2.86; 95% CI, 1.24–6.62). Subjects who quit smoking demonstrated large weight gain (≥1%/year) significantly more frequently than the other subjects (p < 0.001). In sex-specific analysis, starting to exercise was independently associated with NAFLD remission in men (AOR, 2.38; 95% CI, 1.25–4.53).

Biomarkers and their relative contributions to identifying coronary artery stenosis based on coronary computed tomography angiography in asymptomatic adults

BACKGROUND

Coronary computed tomography angiography (CCTA) has emerged as an important, non-invasive imaging modality for the assessment of coronary vascular disease. However, CCTA as a screening tool still has issues with radiation exposure and cost in asymptomatic adults. In this study, we investigated the relationship between cardio-metabolic biomarkers and coronary artery stenosis on CCTA in asymptomatic, apparently healthy adults.

METHODS

Data for this cross-sectional study were obtained from 306 subjects who underwent a comprehensive medical check-up including CCTA. A 128-slice CT device was used to detect earlier stages of coronary stenosis, which was defined as > 25% luminal reduction in the most severe stenosis in the calcified segments of the coronary arteries.

RESULTS

On multivariate analysis, after adjustment for age, only γ-glutamyl transferase (GGT) was significantly and independently associated with CCTA stenosis (OR 1.006, 95% CI 1.001-1.011, P = .026). In a subgroup analysis of 103 subjects with brachial-ankle pulse wave velocity (baPWV) data, baPWV was significantly associated with CCTA stenosis (OR 1.005; 95% CI 1.003-1.008, P < .001).

CONCLUSIONS

GGT and baPWV were associated independently with the presence of CCTA stenosis in apparently healthy adults. Further research is needed to re-confirm on these findings.

The combination of fatty liver and increased gamma-glutamyl transpeptidase levels as a risk factor for atherosclerotic plaque development in apparently healthy people

Background/aim

To elucidate how the combination of fatty liver and increased serum gamma-glutamyl transpeptidase (GGT) levels influences atherosclerotic plaque development in apparently healthy people.

Materials and methods

The study population included people who had received an annual health checkup for more than 7 years and had no evidence of carotid plaque at baseline. We investigated the risk factors for carotid plaque occurrence using the Cox proportional hazards model.

Results

A total of 107 people (76 men and 31 women; median age, 49 years) were enrolled. At baseline, fatty liver and a serum GGT level ≥50 U/L were observed in 13 and 38 people, respectively. During a median follow-up period of 13.3 years, carotid plaques appeared in 34 people. Multivariate analysis revealed that the combination of fatty liver and a serum GGT level ≥50 U/L was the only significant risk factor for carotid plaque occurrence (age- and sex-adjusted hazard ratio: 5.55; 95% confidence interval 1.70–18.14; P = 0.005).

Conclusion

The combination of fatty liver and increased serum GGT levels raises the risk for atherosclerotic plaque development in apparently healthy people.

Allyl isothiocyanate ameliorates lipid accumulation and inflammation in nonalcoholic fatty liver disease via the Sirt1/AMPK and NF-κB signaling pathways

BACKGROUND

Allyl isothiocyanate (AITC), a classic anti-inflammatory and antitumorigenic agent, was recently identified as a potential treatment for obesity and insulin resistance. However, little is known about its direct impact on the liver.

AIM

To investigate the effect and underlying mechanism of AITC in nonalcoholic fatty liver disease (commonly referred to as NAFLD).

METHODS

To establish a mouse and cellular model of NAFLD, C57BL/6 mice were fed a high fat diet (HFD) for 8 wk, and AML-12 cells were treated with 200 μM palmitate acid for 24 h. For AITC treatment, mice were administered AITC (100 mg/kg/d) orally and AML-12 cells were treated with AITC (20 μmol/L).

RESULTS

AITC significantly ameliorated HFD-induced weight gain, hepatic lipid accumulation and inflammation in vivo. Furthermore, serum alanine aminotransferase and aspartate aminotransferase levels were markedly reduced in AITC-treated mice. Mechanistically, AITC significantly downregulated the protein levels of sterol regulatory element­binding protein 1 (SREBP1) and its lipogenesis target genes and upregulated the levels of proteins involved in fatty acid β-oxidation, as well as the upstream mediators Sirtuin 1 (Sirt1) and AMP-activated protein kinase α (AMPKα), in the livers of HFD-fed mice. AITC also attenuated the nuclear factor kappa B (NF-κB) signaling pathway. Consistently, AITC relieved palmitate acid-induced lipid accumulation and inflammation in AML-12 cells in vitro through the Sirt1/AMPK and NF-κB signaling pathways. Importantly, further studies showed that the curative effect of AITC on lipid accumulation was abolished by siRNA-mediated knockdown of either Sirt1 or AMPKα in AML-12 cells.

CONCLUSION

AITC significantly ameliorates hepatic steatosis and inflammation by activating the Sirt1/AMPK pathway and inhibiting the NF-κB pathway. Therefore, AITC is a potential therapeutic agent for NAFLD.

Nonalcoholic Fatty Liver Disease Is Associated With Arterial Distensibility and Carotid Intima-Media Thickness: (from the Multi-Ethnic Study of Atherosclerosis)

Nonalcoholic fatty liver disease (NAFLD) is considered a potential independent risk factor for cardiovascular disease (CVD). The Multi-Ethnic Study of Atherosclerosis cohort enrolled 6,814 adults without previous CVD. We excluded 2,692 participants who had missing variables, were heavy drinkers, or history of steroid use and/or chronic liver disease. NAFLD was defined using noncontrast cardiac CT and a liver/spleen Hounsfield Unit attenuation ratio <1. Ultrasound-measured carotid arterial compliance and stiffness, was expressed as distensibility coefficient and Young's modulus. Common and internal carotid intima-media thickness (CIMT) and coronary artery calcium (CAC) >0 were used as markers of subclinical CVD. A multivariate robust linear regression and logistic regression analysis were done to evaluate the association of NAFLD and this subclinical CVD markers. Our analysis of 4,123 participants showed 55% were female with a mean age of 63 (±10) years, 39% white, 10% Chinese, 28% black, and 23% were Hispanic. The prevalence of NAFLD was 17% (n = 729). Patients with NAFLD had higher distensibility coefficient and higher CIMT. Multivariate linear regression analysis showed the presence of NAFLD was associated with both the common carotid and internal carotid IMT and logCAC. Logistic analysis showed an independent association with CAC > 0 (odds ratio [OR] 1.44 95% confidence interval [CI] 1.18, 1.75) and CIMT > 1 mm (OR 1.30 95% 1.08, 1.56). When stratified by race the association with CIMT > 1 mm was significant in whites (OR 1.37 95% 1.00, 1.90) and Hispanic (OR 1.53 95% 1.08, 2. 17) and CAC > 0 was significant in Hispanics (OR 1.52 95% 1.06, 2.19). In conclusion, NAFLD is modestly associated with carotid IMT and coronary artery calcification in a multiethnic population.

Gut Microbiota and Risk of Persistent Nonalcoholic Fatty Liver Diseases

Gut dysbiosis is regarded as a pathogenetic factor of nonalcoholic fatty liver disease (NAFLD), but its role in NAFLD persistence is unknown. We investigated the influence of the gut microbiota on persistent NAFLD. This cohort study included 766 subjects with 16S ribosomal RNA (rRNA) gene sequencing data from fecal samples at baseline who underwent repeated health check-up examinations. Fatty liver was determined using ultrasound at baseline and follow-up. Participants were categorized into four groups: none (control), developed, regressed, or persistent NAFLD. The persistent NAFLD group had lower richness compared with the control group. Significant differences were also found in both non-phylogenic and phylogenic beta diversity measures according to NAFLD persistence. Pairwise comparisons indicated that taxa abundance mainly differed between the control and persistent NAFLD groups. A relative high abundance of Fusobacteria and low abundance of genera Oscillospira and Ruminococcus of the family Ruminococcaceae and genus Coprococcus of the family Lachnospiraceae were found in the persistent NAFLD group. Based on the functional predictions, pathways related to primary and secondary bile acid biosynthesis were highly detected in the persistent NAFLD group compared with the control group. These findings support that the composition of the gut microbiome associated with dysregulation of bile acid biosynthetic pathways may contribute to the persistence of NAFLD. This is the first cohort study to demonstrate the influence of microbiota on persistent NAFLD. Our findings may help identify potential targets for therapeutic intervention in NAFLD.

Efficacy of a non-invasive model in predicting the cardiovascular morbidity and histological severity in non-alcoholic fatty liver disease

BACKGROUND

Insulin resistance (IR) in cases of non-alcoholic fatty liver disease (NAFLD) is connected to remarkable liver cell inflammation and cardiovascular complications. Given the prevalence of NAFLD and its association with potential sequels, there is a strong need for an accurate non-invasive tool to monitor the progression of NAFLD.

METHODS

272 patients with NAFLD and cardio-metabolic risk factors were tested for HOMA-IR, mean platelet volume (MPV), neutrophil-lymphocyte ratio (NLR), uric acid, ferritin, lipid profile, liver stiffness measurement (LSM), controlled attenuation parameter (CAP) by fibroscan and carotid intima media thickness (CIMT). Liver biopsy was performed to validate the results.100 healthy controls were selected. A score was constructed and applied to a validation group (n = 61).

RESULTS

Logistic regression revealed that significant fibrosis and cardiovascular risk in NAFLD were independently associated with AST/ALT ratio (p = 0.000), GGT (p = 0.000), CIMT (p = 0.001), uric acid (p = 0.000), VLDL (p = 0.000), HOMA-IR (p = 0.000), ferritin (p = 0.000) CAP (p = 0.000), LSM (p0.000). A non-invasive model was formulated by which a value > 15 was accurate in identification of advanced fibrosis and cardiovascular risk with a sensitivity of 97.3%, specificity 97%.

CONCLUSION

The score correlated well with the results of liver biopsy and can be repeated with great flexibility to assess severity of NAFLD.

Relationship Among Fatty Liver, Specific and Multiple-Site Atherosclerosis, and 10-Year Framingham Score

Despite a well-documented increase in the prevalence of subclinical atherosclerosis in patients with steatosis, the relationship among steatosis and atherosclerosis, specific atherosclerotic sites, multiple-site atherosclerosis, and cardiovascular risk prediction is incompletely understood. We studied the relationship among steatosis, atherosclerosis site, multiple-site atherosclerosis, coronary artery calcification (CAC), and 10-year Framingham Risk Score (FRS) in 2,554 patients with one or more cardiovascular risk factors (CVRF), free of cardiovascular events and other chronic liver diseases, and drinking less than 50 g alcohol/day. All patients underwent arterial ultrasound (carotid [CP] and femoral [FP] plaques defined as intima-media thickness (IMT) > 1.5 mm), coronary computed tomography scan (severe CAC if ≥ 100), 10-year FRS calculation, and steatosis detection by the fatty liver index (FLI, present if score ≥ 60). Patients with steatosis (36% of total) had higher prevalence of CP (50% versus 45%, P = 0.004) and higher CAC (181 ± 423 versus 114 ± 284, P < 0.001) but similar prevalence of FP (53% versus 50%, P = 0.099) than patients without steatosis. Steatosis was associated with carotid IMT and CAC, but not with FP, independent of age, diabetes, hypertension, and tobacco use (P < 0.001). Fifty-three percent of patients had at least 2-site atherosclerosis and steatosis was associated with at least 2-site atherosclerosis independent of age and CVRF (odds ratio = 1.21, 95% confidence interval 1.01-1.45, P = 0.035). Sixty-four percent of patients with steatosis had a FRS score of 10% or more. FLI was associated with FRS beyond the CVRF or the number of atherosclerosis sites (P < 0.001). Adding FLI to CVRF predicted an FRS greater than or equal to 10% better than CVRF alone (area under the receiver operating characteristic curve = 0.848 versus 0.768, P < 0.001). Conclusion: Steatosis is associated with carotid and coronary, but not femoral atherosclerosis, and with cardiovascular mortality risk. The multiple-site involvement and quantitative tonic relationship could reinforce the prediction of cardiovascular mortality or events over classical CVRF or imaging-based detection of atherosclerosis.

Crosstalk between nonalcoholic fatty liver disease and cardiometabolic syndrome

Nonalcoholic fatty liver disease (NAFLD) is a chronic condition characterized by fat accumulation combined with low-grade inflammation in the liver. A large body of clinical and experimental data shows that increased flux of free fatty acids from increased visceral adipose tissue and de novo lipogenesis can lead to NAFLD and insulin resistance. Thus, individuals with obesity, insulin resistance, and dyslipidaemia are at the greatest risk of developing NAFLD. Conversely, NAFLD is a phenotype of cardiometabolic syndrome. Notably, researchers have discovered a close association between NAFLD and impaired glucose metabolism and focused on the role of NAFLD in the development of type 2 diabetes. Moreover, recent studies provide substantial evidence for an association between NAFLD and atherosclerosis and cardiometabolic disorders. Even if NAFLD can progress into severe liver disorders including nonalcoholic steatohepatitis (NASH) and cirrhosis, the majority of subjects with NAFLD die from cardiovascular disease eventually. In this review, we propose a potential pathological link between NAFLD/NASH and cardiometabolic syndrome. The potential factors that can play a pivotal role in this link, such as inflammation, insulin resistance, alteration in lipid metabolism, oxidative stress, genetic predisposition, and gut microbiota are discussed.

High prevalence of non-alcoholic fatty liver disease and metabolic risk factors in Guatemala: A population-based study

BACKGROUND

There are no data on the prevalence of non-alcoholic fatty liver disease (NAFLD) in general population samples in Guatemala or in other Central American countries. The prevalence and distribution of NAFLD and its associated risk factors were evaluated in a population-based sample of adults in Guatemala.

METHODS

Cross-sectional study of 411 men and women 40 years of age or older residing in urban and rural areas of Guatemala. Metabolic outcomes included obesity, central obesity, hypercholesterolemia, diabetes, and metabolic syndrome (MetS). Liver disease outcomes included elevated liver enzymes, elevated Fatty Liver Index (FLI), and elevated FIB-4 score.

RESULTS

The overall prevalence of obesity, central obesity, diabetes, and MetS were 30.9, 74.3, 21.6, and 64.2%, respectively. The fully-adjusted prevalence ratios (95% CI) for obesity, central obesity, diabetes, and MetS comparing women to men were 2.83 (1.86-4.30), 1.72 (1.46-2.02), 1.18 (1.03-1.34), and 1.87 (1.53-2.29), respectively. The overall prevalence of elevated liver enzymes (ALT or AST), elevated FLI, and elevated FIB-4 scores were 38.4, 60.1, and 4.1%, respectively. The fully-adjusted prevalence ratios (95% CI) for elevated liver enzymes (either ALT or AST) and elevated FLI score comparing women to men were 2.99 (1.84-4.86) and 1.47 (1.18-1.84), respectively.

CONCLUSIONS

The prevalence of metabolic abnormalities and liver outcomes in this general population study was very high. The prevalence of metabolic and liver abnormalities was particularly high among women, an observation that could explain the atypical 1:1 male to female ratio of liver cancer in Guatemala.

Association between non-alcoholic fatty liver disease evaluated by transient elastography with extracranial carotid atherosclerosis in a multiethnic Asian community

Background and Aim

There is not much data on the association between non‐alcoholic fatty liver disease (NAFLD) and advanced fibrosis assessed using Fibroscan with carotid intima‐media thickness (CIMT) in the general population. The objective of this study was to evaluate the association between NAFLD and advanced fibrosis, as diagnosed by Fibroscan, with an increased CIMT in the Malaysian population.

Methods

A cross‐sectional study of government officers and their family members attending a health screening at a public healthcare facility was conducted. All subjects underwent clinical evaluation, biochemical testing, anthropometry, ultrasound carotid Doppler, and Fibroscan examination.

Results

Data for 251 subjects were analyzed (mean age 47.1 ± 12.4 years, 74.1% male). Prevalence of NAFLD and advanced fibrosis were 57.4 and 17.5%, respectively. Independent factors associated with NAFLD were waist circumference (odds ratio [OR] = 1.077, 95% confidence interval [CI] 1.038–1.118, P < 0.001) and serum alanine aminotransferase (ALT) (OR = 1.039, 95% CI 1.005–1.074, P = 0.024). Independent factors associated with advanced fibrosis were male gender (OR = 4.847, 95% CI 1.369–17.155, P = 0.014) and serum aspartate aminotransferase (AST) (OR = 1.057, 95% CI 1.003–1.113, P = 0.036). Prevalence of increased CIMT was 29.0%. Independent factor associated with increased CIMT was older age (OR = 1.146, 95% CI 1.067–1.231, P < 0.001). Of the subjects, 34.5% with NAFLD had increased CIMT compared to 19.1% of the subjects without NAFLD (P = 0.063). Advanced fibrosis was not associated with increased CIMT.

Conclusions

Prevalence of NAFLD, advanced liver fibrosis, and increased CIMT were high. NAFLD and advanced liver fibrosis appeared not to be associated with increased CIMT. However, a larger sample size is needed to demonstrate whether there is any association.

Ideal Cardiovascular Health Is Inversely Associated with Nonalcoholic Fatty Liver Disease: A Prospective Analysis

BACKGROUND

Cardiovascular health has been proven to be associated with major cardiometabolic diseases. However, little is known of associations between cardiovascular health and nonalcoholic fatty liver disease.

METHODS

This study included 3424 adults aged ≥40 years who were free of nonalcoholic fatty liver disease at baseline from a community cohort followed for up to 5 years. Liver ultrasonography was conducted at baseline and at follow-up to diagnose incident nonalcoholic fatty liver disease. Six metrics including smoking, physical activity, body mass index, total cholesterol, blood pressure, and fasting glucose were used to define cardiovascular health status. Associations of individual cardiovascular health metrics, number of cardiovascular health metrics, and overall cardiovascular health status at baseline, as well as changes in cardiovascular health during follow-up with risks of developing nonalcoholic fatty liver disease, were examined.

RESULTS

A total of 649 participants developed nonalcoholic fatty liver disease during follow-up. Risks of nonalcoholic fatty liver disease reduced in a dose-response manner in participants with 3-4 ideal cardiovascular health metrics (odds ratio 0.50; 95% confidence interval, 0.41-0.61) and in participants with 5-6 ideal metrics (odds ratio 0.34; 95% confidence interval 0.22-0.51) compared with participants with 0-2 ideal metrics. An overall ideal or intermediate cardiovascular health was associated with 37% reduction in developing nonalcoholic fatty liver disease compared with poor cardiovascular health. In addition, improving cardiovascular health during follow-up reduced the risk by 71% compared with deteriorating cardiovascular health. Furthermore, an overall ideal or intermediate cardiovascular health was significantly associated with a lower fibrosis score in nonalcoholic fatty liver disease patients compared with an overall poor cardiovascular health.

CONCLUSIONS

Ideal cardiovascular health was inversely associated with risks of nonalcoholic fatty liver disease. Although treatment of nonalcoholic fatty liver disease and subsequent inflammation and fibrosis remains a challenge, cardiovascular health goals should be advocated for nonalcoholic fatty liver disease prevention.

Agonism for the bile acid receptor GPBAR1 reverses liver and vascular damage in a mouse model of steatohepatitis

Nonalcoholic steatohepatitis (NASH) is associated with an increased risk of developing cardiovascular complications and mortality, suggesting that treatment of NASH might benefit from combined approaches that target the liver and the cardiovascular components of NASH. Using genetic and pharmacologic approaches, we show that G protein-coupled bile acid-activated receptor 1 (GPBAR1) agonism reverses liver and vascular damage in mouse models of NASH. NASH is associated with accelerated vascular inflammation representing an independent risk factor for development of cardiovascular diseases and cardiovascular-related mortality. GPBAR1, also known as TGR5, is a G protein-coupled receptor for secondary bile acids that reduces inflammation and promotes energy expenditure. Using genetic and pharmacologic approaches, we investigated whether GPBAR1 agonism by 6β-ethyl-3α,7β-dihydroxy-5β-cholan-24-ol (BAR501) reverses liver and vascular damage induced by exposure to a diet enriched in fat and fructose (HFD-F). Treating HFD-F mice with BAR501 reversed liver injury and promoted the browning of white adipose tissue in a Gpbar1-dependent manner. Feeding HFD-F resulted in vascular damage, as shown by the increased aorta intima-media thickness and increased expression of inflammatory genes (IL-6,TNF-α, iNOS, and F4/80) and adhesion molecules (VCAM, intercellular adhesion molecule-1, and endothelial selectin) in the aorta, while reducing the expression of genes involved in NO and hydrogen sulfide generation, severely altering vasomotor activities of aortic rings in an ex vivo assay. BAR501 reversed this pattern in a Gpbar1-dependent manner, highlighting a potential role for GPBAR1 agonism in treating the liver and vascular component of NASH.-Carino, A., Marchianò, S., Biagioli, M., Bucci, M., Vellecco, V., Brancaleone, V., Fiorucci, C., Zampella, A., Monti, M. C., Distrutti, E., Fiorucci, S. Agonism for the bile acid receptor GPBAR1 reverses liver and vascular damage in a mouse model of steatohepatitis.

Nonalcoholic fatty liver disease contributes to subclinical atherosclerosis: A systematic review and meta-analysis

Nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of atherosclerotic cardiovascular disease. In our meta‐analysis, we aimed to assess the correlation of NAFLD and four surrogate markers of subclinical atherosclerosis. PubMed, Embase, and the Cochrane Library were searched up until April 2017. Original studies investigating the association between NAFLD and subclinical atherosclerosis were included. The outcome data were extracted and pooled for the effect estimate by using a random‐effects model. We used the Newcastle‐Ottawa Quality Assessment Scale to assess the quality of the included studies. Of the 434 initially retrieved studies, 26 studies involving a total of 85,395 participants (including 29,493 patients with NAFLD) were included in this meta‐analysis. The Newcastle‐Ottawa Quality Assessment Scale scores suggested the included studies were of high quality. The pooled effects estimate showed that subjects with NAFLD exhibited a significant independent association with subclinical atherosclerosis compared to the non‐NAFLD group (odds ratio, 1.60; 95% confidence interval, 1.45‐1.78). Subgroup analysis suggested that the presence of NAFLD yielded a remarkable higher risk of increased carotid artery intima‐media thickness/plaques, arterial stiffness, coronary artery calcification, and endothelial dysfunction with odds ratios (95% confidence interval) of 1.74 (1.47‐2.06), 1.56 (1.24‐1.96), 1.40 (1.22‐1.60), and 3.73 (0.99‐14.09), respectively. Conclusion: Our meta‐analysis revealed a close link between NAFLD and subclinical atherosclerosis in light of four different indices. Patients with NAFLD might benefit from screening and surveillance of early atherosclerosis, which would facilitate the prediction of potential cardiovascular disease burden, risk stratification, and appropriate intervention in the long term. (Hepatology Communications 2018;2:376‐392)

Hypertension, diabetes, atherosclerosis and NASH: Cause or consequence?

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common forms of chronic liver disease worldwide and its prevalence is expected to continue rising. NAFLD has traditionally been considered a consequence of metabolic syndrome (MetS). However, the link between NAFLD and MetS components, especially type 2 diabetes mellitus (T2DM), hypertension (HTN), and cardiovascular disease (CVD) is more complex than previously thought. Indeed, the adverse effects of NAFLD extend far beyond the liver, with a large body of clinical evidence now suggesting that NAFLD may precede and/or promote the development of T2DM, HTN and atherosclerosis/CVD. The risk of developing these cardiometabolic diseases parallels the underlying severity of NAFLD. Accumulating evidence suggests that the presence and severity of NAFLD is associated with an increased risk of incident T2DM and HTN. Moreover, long-term prospective studies indicate that the presence and severity of NAFLD independently predicts fatal and nonfatal CVD events. In this review, we critically discuss the rapidly expanding body of clinical evidence that supports the existence of a bi-directional relationship between NAFLD and various components of MetS, particularly T2DM and HTN, as well as the current knowledge regarding a strong association between NAFLD and CVD morbidity and mortality. Finally, we discuss the most updated putative biological mechanisms through which NAFLD may contribute to the development of HTN, T2DM and CVD.

Non-alcoholic fatty liver disease and its relationship with cardiovascular disease and other extrahepatic diseases

Key physiological functions of the liver, including glucose and lipid metabolism, become disturbed in the setting of non-alcoholic fatty liver disease (NAFLD) and may be associated with a systemic inflammatory 'milieu' initiated in part by liver-secreted cytokines and molecules. Consequently, the pathophysiological effects of NAFLD extend beyond the liver with a large body of clinical evidence demonstrating NAFLD to be independently associated with both prevalent and incident cardiovascular disease (CVD), chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). The magnitude of risk of developing these extrahepatic diseases parallels the underlying severity of NAFLD, such that patients with non-alcoholic steatohepatitis (NASH) appear to be at greater risk of incident CVD, CKD and T2DM than those with simple steatosis. Other modifiers of risk may include genetic variants (eg, patatin-like phospholipase domain-containing 3 and trans-membrane 6 superfamily member 2 polymorphisms), visceral adipose tissue accumulation, dietary intake and the gut microbiome. Emerging data also suggest that NAFLD may be a risk factor for colonic neoplasia and reduced bone mineral density, especially among men. Importantly, improvement/resolution of NAFLD is associated with a reduced incidence of T2DM and improved kidney function, adding weight to causality and suggesting liver focused treatments may reduce risk of extrahepatic complications. Awareness of these associations is important for the clinicians such that CVD risk factor management, screening for T2DM and CKD are part of the routine management of patients with NAFLD.

Non-alcoholic fatty liver disease and cardiovascular risk

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease associated with insulin resistance and metabolic syndrome. The spectrum of disease ranges from simple steatosis to steatohepatitis and progression to cirrhosis. Compelling evidence over the past several years has substantiated a significant link between NAFLD and cardiovascular disease ranging from coronary artery disease to subclinical carotid atherosclerosis. Close follow up, treatment of risk factors for NAFLD, and cardiovascular risk stratification are necessary to predict morbidity and mortality in this subset of patients.

Metabolite profiling identifies anandamide as a biomarker of nonalcoholic steatohepatitis

The discovery of metabolite-phenotype associations may highlight candidate biomarkers and metabolic pathways altered in disease states. We sought to identify novel metabolites associated with obesity and one of its major complications, nonalcoholic fatty liver disease (NAFLD), using a liquid chromatography-tandem mass spectrometry method. In 997 individuals in Framingham Heart Study Generation 3 (FHS Gen 3), we identified an association between anandamide (AEA) and BMI. Further examination revealed that AEA was associated with radiographic hepatic steatosis. In a histologically defined NAFLD cohort, AEA was associated with NAFLD severity, the presence of nonalcoholic steatohepatitis, and fibrosis. These data highlight AEA as a marker linking cardiometabolic disease and NAFLD severity.

Gamma-glutamyltransferase and risk of cardiovascular mortality: A dose-response meta-analysis of prospective cohort studies

BACKGROUND

Serum gamma-glutamyltransferase (GGT) elevation likely contributes to cardiovascular (CV) mortality, however it has remained unknown whether a dose-response relationship exists between serum GGT and CV mortality.

METHODS

We searched the PubMed, EMBASE, and Cochrane library databases for prospective cohort studies published up to October 2, 2016. Summary hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were calculated using a fixed effects model.

FINDINGS

Nine prospective studies, including 527,589 participants and more than 7,011 cases, were included in this meta-analysis. For the moderate, high, and highest levels of GGT, the pooled HRs of CV mortality were 1.11 (95% CI = 1.04-1.19), 1.29 (95% CI = 1.21-1.38) and 1.59 (95% CI = 1.47-1.72), respectively (all p < 0.05 as compared to the lowest levels of GGT). Additionally, the HR per incremental increase of GGT by 10 U/L was 1.10 (95% CI = 1.08-1.11). Evidence of a positive relationship with nonlinear trend for GGT elevation with CV mortality in females was found (P = 0.04 for nonlinearity). However, a linear model was better fit to illustrate the GGT-CV mortality among males (P = 0.304 for nonlinearity).

CONCLUSIONS

These findings indicate that serum GGT activity within the reference interval is positively associated with increased risk of CV mortality in a dose-response manner.

Non-alcoholic fatty liver disease and progression of coronary artery calcium score: a retrospective cohort study

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD), a hepatic manifestation of the metabolic syndrome, was associated with subclinical atherosclerosis in many cross-sectional studies, but the prospective association between NAFLD and the progression of atherosclerosis has not been evaluated. This study was conducted to evaluate the association between NAFLD and the progression of coronary atherosclerosis.

METHODS

This retrospective cohort study included 4731 adult men and women with no history of cardiovascular disease (CVD), liver disease or cancer at baseline who participated in a repeated regular health screening examination between 2004 and 2013. Fatty liver was diagnosed by ultrasound based on standard criteria, including parenchymal brightness, liver-to-kidney contrast, deep beam attenuation and bright vessel walls. Progression of coronary artery calcium (CAC) scores was measured using multidetector CT scanners.

RESULTS

The average duration of follow-up was 3.9 years. During follow-up, the annual rate of CAC progression in participants with and without NAFLD were 22% (95% CI 20% to 23%) and 17% (16% to 18%), respectively (p<0.001). The multivariable ratio of progression rates comparing participants with NAFLD with those without NAFLD was 1.04 (1.02 to 1.05; p<0.001). The association between NAFLD and CAC progression was similar in most subgroups analysed, including in participants with CAC 0 and in those with CAC >0 at baseline.

CONCLUSIONS

In this large cohort study of adult men and women with no history of CVD, NAFLD was significantly associated with the development of CAC independent of cardiovascular and metabolic risk factors. NAFLD may play a pathophysiological role in atherosclerosis development and may be useful to identify subjects with a higher risk of subclinical disease progression.

Non-alcoholic fatty liver diseases and risk of colorectal neoplasia

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with colorectal neoplasia. Yet, NAFLD ranges from simple steatosis to steatohepatitis with advanced fibrosis.

AIM

To investigate the risk of colorectal neoplasia according to the presence and severity of NAFLD.

METHODS

A total of 26 540 asymptomatic adults who underwent same day first-time colonoscopy and abdominal ultrasonography as a health check-up programme were analysed. NAFLD was diagnosed by ultrasonography. Advanced colorectal neoplasia was defined as an invasive cancer or adenoma that was at least 10 mm in diameter, had high-grade dysplasia, or had villous histological characteristics or any combination thereof.

RESULTS

NAFLD patients had a higher prevalence of any colorectal neoplasia (38.0% vs. 28.9%) and advanced colorectal neoplasia (2.8% vs. 1.9%) compared to those without NAFLD. In a multivariable model adjusted for age, sex, smoking, alcohol, body mass index, first-degree family history of colorectal cancer, aspirin use and metabolic factors, the odd ratios comparing patients with NAFLD to those without were 1.10 [95% confidence interval (CI): 1.03-1.17] for any colorectal neoplasia and 1.21 (95% CI: 0.99-1.47) for advanced colorectal neoplasia. When NAFLD patients were further stratified according to the non-invasive parameters of liver disease severity, the risk of any colorectal neoplasia or advanced colorectal neoplasia was higher for those with severe liver diseases than those with mild liver diseases.

CONCLUSIONS

The presence and severity of NAFLD were closely associated with any colorectal neoplasia and advanced colorectal neoplasia, suggesting that clinicians should be aware of the increased risk of colorectal neoplasia in patients with NAFLD.

Fatty liver is associated with an increased risk of diabetes and cardiovascular disease - Evidence from three different disease models: NAFLD, HCV and HIV

Fatty liver, which frequently coexists with necro-inflammatory and fibrotic changes, may occur in the setting of nonalcoholic fatty liver disease (NAFLD) and chronic infections due to either hepatitis C virus (HCV) or human immunodeficiency virus (HIV). These three pathologic conditions are associated with an increased prevalence and incidence of cardiovascular disease (CVD) and type 2 diabetes (T2D). In this multidisciplinary clinical review, we aim to discuss the ever-expanding wealth of clinical and epidemiological evidence supporting a key role of fatty liver in the development of T2D and CVD in patients with NAFLD and in those with HCV or HIV infections. For each of these three common diseases, the epidemiological features, pathophysiologic mechanisms and clinical implications of the presence of fatty liver in predicting the risk of incident T2D and CVD are examined in depth. Collectively, the data discussed in this updated review, which follows an innovative comparative approach, further reinforce the conclusion that the presence of fatty/inflamed/fibrotic liver might be a shared important determinant for the development of T2D and CVD in patients with NAFLD, HCV or HIV. This review may also open new avenues in the clinical and research arenas and paves the way for the planning of future, well-designed prospective and intervention studies.