Assessment of endothelial function in patients with nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) and its association to cardiovascular disease: A comprehensive meta-analysis

Background

Non-alcoholic fatty liver disease (NAFLD) affects up to nearly a third of the Western population and has been inconsistently associated with cardiovascular diseases (CVDs). Therefore, we conducted a comprehensive meta-analysis to quantify the correlation of NAFLD with all major vascular diseases, acute coronary syndrome (ACS), subclinical atherosclerosis and endothelial dysfunction.

Methods

We searched PubMed and Embase for studies looking at the relationship between NAFLD and cardiovascular diseases published through September 2023. The parameters we used to assess cardiovascular diseases include acute coronary syndrome, brachial flow-mediated dilatation (FMD), serum asymmetric dimethylarginine (ADMA), carotid intima-media thickness (CIMT), and carotid stenosis (>50%). Data from these studies were then collected and meta-analysis was performed using the random effects model. RevMan v5.4 was used for statistical analysis.

Results

We interrogated a total of 114 publications which met our inclusion criteria. NAFLD patients showed statistically significant reduction in FMD% [MD: -4.83 (95% CI: -5.84 to 3.81, p < .00001)] and increased serum ADMA [MD: 0.08 (95% CI: 0.05-0.11, p < .00001)]. Mean CIMT was also increased in NAFLD patients [MD 0.13 (95% CI: 0.12-0.14, p < .00001)]. NAFLD showed a higher prevalence of pathological CIMT [MD: 0.11 (95% CI: 0.10-0.12, p < .00001)] and increased carotid plaques [OR: 2.08 (95% CI: 1.52-2.86, p < .00001)]. Furthermore, we demonstrated statistically significant increase in cardiovascular diseases among NAFLD patients compared to controls [OR: 1.92 (95% CI: 1.53-2.41, p < .00001)].

Conclusion

NAFLD is a strong predictor for endothelial dysfunction, subclinical atherosclerosis and cardiovascular disease. Further studies are required to determine whether incidental findings of fatty liver on abdominal ultrasonography should prompt the need for detailed assessment of other CVD risk factors.

Endothelial dysfunction and cardiovascular risk in non-alcoholic fatty liver disease – a systematic review and meta-analysis

Background

Nonalcoholic fatty liver disease (NAFLD) is a prevalent metabolic disorder that has been associated with an increased risk of cardiovascular diseases. Endothelial dysfunction, characterized by impaired flow-mediated dilation (FMD) of the brachial artery, is a known predictor of cardiovascular risk. However, the relationship between NAFLD and endothelial dysfunction, as well as the impact of NAFLD on clinical cardiovascular events, remains unclear.

Objective

The aim of this systematic literature review was to determine the association between endothelial dysfunction, as measured by FMD of the brachial artery, and NAFLD. Additionally, we aimed to investigate the relationship between NAFLD and clinical cardiovascular events (CVE).

Methods

A systematic search was conducted in PubMed, Scopus, ScienceDirect, and Google Scholar for articles published between 2000 and July 2023. The reference lists of the included studies were also searched to retrieve possible additional studies. Original studies published in English focusing on adults with NAFLD and endothelial dysfunction are included. Editorials, commentaries, letters and studies focusing on pediatric populations and non-NAFLD liver diseases were excluded. The quality of included studies was appraised using the Newcastle–Ottawa scale. Meta-analyses were performed using Review Manager 5.4 software.

Results

The initial search yielded a total of 1792 articles and ultimately only 20 studies met the criteria. A total 6396 NAFLD patients were studied. Meta-analysis showed that individuals diagnosed with NAFLD had significantly lower brachial FMD values compared to their respective control groups (standardized mean difference: -4.63, 95% confidence interval: -5.68 to -3.58, p < 0.0001). Furthermore, NAFLD patients exhibited a significantly higher risk of clinical cardiovascular events compared to controls (odds ratio: 2.61; 95% CI: 1.41–4.83, p < 0.002). Subgroup analysis of studies focusing on non-alcoholic steatohepatitis (NASH) versus pure steatosis demonstrated that individuals with NASH had even lower FMD values than those with pure steatosis (standardized mean difference: -3.84, 95% confidence interval: -7.56 to -0.13, p = 0.03, I2 = 66%).

Limitations, bias and heterogeneity

The review included studies published in English language, over last 23 years and specified database resulted in language bias and might have missed older pertinent studies from another important database. The overall heterogeneity is attributed to variations in study populations, outcome measurements, differences in methodological approaches among included studies, and diverse diagnostic criteria for NAFLD.

Conclusion

Individuals with NAFLD exhibited impaired brachial FMD, indicating compromised endothelial function. Furthermore, NAFLD patients had an elevated risk of clinical cardiovascular events.

Relation between non-alcoholic fatty liver disease and carotid artery intimal media thickness as a surrogate for atherosclerosis: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis without heavy alcohol consumption or other chronic conditions, encompasses a spectrum from non-alcoholic fatty liver to non-alcoholic steatohepatitis leading to cirrhosis. This analysis aimed to investigate the correlation between NAFLD and carotid intimal media thickness (C-IMT), a non-invasive surrogate for atherosclerosis.

METHODOLOGY

Database searches, including PubMed, EMBASE and Cochrane Library, yielded studies up to April 2023. Included were studies exploring the NAFLD-C-IMT relationship in populations aged >18 years. Exclusions comprised non-English papers, those involving animals or pediatric populations and studies lacking control groups.

RESULTS

No statistical significance was noted between mild and moderate NAFLD compared to the control group regarding C-IMT [95% confidence intervals (CI): -0.03, 0.12] and (95% CI: -0.03, 0.21), respectively. There was a statistically significant difference only in the Severe NAFLD group ( P value 0.03). NAFLD with and without metabolic syndrome showed statistically significant differences compared to control regarding C-IMT (95% CI: 0.04, 0.12) and (95% CI: 0.01, 0.07), respectively. Fifty-nine studies were mentioned without classification of NAFLD severity and revealed a high statistically significant difference between NAFLD and controls regarding C-IMT with (95% CI: 0.09, 0.12, P < 0.00001). Stratified analysis according to sex was done in two studies and revealed statistical differences between NAFLD and control regarding C-IMT in both groups.

CONCLUSION

This meta-analysis underscores a significant association between NAFLD and increased C-IMT, emphasizing the importance of assessing C-IMT in NAFLD patients to identify cardiovascular risk and tailor therapeutic interventions for improved patient outcomes.

Two sides of the same coin: Non-alcoholic fatty liver disease and atherosclerosis

The prevalence of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis remain high, which is primarily due to widespread adoption of a western diet and sedentary lifestyle. NAFLD, together with advanced forms of this disease such as non-alcoholic steatohepatitis (NASH) and cirrhosis, are closely associated with atherosclerotic-cardiovascular disease (ASCVD). In this review, we discussed the association between NAFLD and atherosclerosis and expounded on the common molecular biomarkers underpinning the pathogenesis of both NAFLD and atherosclerosis. Furthermore, we have summarized the mode of function and potential clinical utility of existing drugs in the context of these diseases.

The relationship between metabolic syndrome criteria and pentraxin-3 levels in children

OBJECTIVES

While the positive correlation was shown in a few studies which investigated the relationship between obesity and pentraxin-3 (PTX-3) levels, different findings were obtained in other studies. We aimed to determine PTX-3 levels in obese and healthy children, and their relationship with Metabolic Syndrome (MetS) criteria.

METHODS

105 children and adolescents were considered as the study population. Participants were divided into three groups; obese and MetS (OM+), obese and non-MetS (OM-) and the control group. Fasting glucose, blood lipids and PTX-3 levels were measured. Ultrasonography was performed to detect hepatic steatosis. MetS and hepatic steatosis were investigated by dividing the patients into two groups according to PTX-3 levels.

RESULTS

The study population consisted of 37 patients with OM+; 35 patients with OM- and 33 healthy children. OM+ patients had higher fasting insulin (p<0.001), homeostatic model assessment for insulin resistance (p<0.001), triglyceride (p<0.001) and lower high-density lipoprotein (p=0.001). The PTX-3 level was higher in the OM+ group compared to both OM- group and the control group (p=0.002). When two groups were generated according to PTX-3 level, a higher frequency of MetS was detected in the high PTX 3 group than in all three major MetS diagnostic criteria groups. Moreover, there was more hepatic steatosis in the high PTX-3 group independent from obesity and MetS.

CONCLUSIONS

Higher PTX-3 levels were present in children and adolescent obese patients with MetS.

Non-alcoholic fatty liver disease and compromised endothelial function in people with type 2 diabetes

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) frequently coexists with type 2 diabetes mellitus (T2DM) and synergistically contributes to the development of atherosclerosis. Flow-mediated dilation (FMD) is a commonly used noninvasive test for assessing endothelial function. The main objective of this study was to explore FMD in patients with T2DM with and without NAFLD.

METHODS

In this cross-sectional study, conducted on people with T2DM, NAFLD was defined as controlled attenuation parameter (CAP) score > 302 dB/m. Endothelial dysfunction was detected when arterial FMD of brachial artery was equal or less than 0.7%. Regression analyses were applied to assess factors associated with impaired FMD.

RESULT

A total of 147 patients (72 with NAFLD and 75 without NAFLD) were included in the final analysis. Patients with NAFLD were more likely to develop FMD ≤ 7% (77.8% vs. 58.7%, P = 0.01). In multivariate analysis, NAFLD (OR = 2.581, 95% CI (1.18-5.62), P = 0.017) and hypertension (HTN) (OR = 3.114, 95% CI (1.31-7.35), P = 0.010) were associated with an increased risk of impaired FMD. However, female sex was associated with a decreased risk of impaired FMD (OR = 0.371, 95% CI (0.15-0.87), P = 0.024).

CONCLUSION

NAFLD is associated with endothelial dysfunction in people with T2DM. This risk is comparable with the risk imposed by HTN, highlighting the importance of screening and management of NAFLD in these patients.

Association of nonalcoholic fatty liver disease and carotid media-intima thickness: A systematic review and a meta-analysis

Introduction

The relationship between cardiovascular disorders and nonalcoholic fatty liver disease (NAFLD) has been extensively studied. To better pool this data and make a more definite conclusion, we performed a meta-analysis to evaluate the association between NAFLD and the thickness of media and intima of carotid artery (CIMT) and cardiovascular disorders.

Methods

We searched PubMed, Ovid, Scopus, ProQuest, Web of Science, and the Cochrane Library, and analyzed the pooled data using R studio and the "metafor" package.

Results

The final analysis included a total of 59 studies with 16,179 cases and 26,120 control individuals. NAFLD was shown to be associated with an increase of 0.1231 mm (20.6%) in carotid artery intima-media thickness (CIMT) (p = 0.002, 95% confidence interval [CI]: 0.0462-0.2000) in individuals with NAFLD. The prevalence of atherosclerotic plaques in the carotid arteries and the occurrence of NAFLD are significantly correlated, according to a meta-analysis based on 17 distinct studies (p = 0.001, 1.28-1.43, 95% CI, odds ratio = 1.356).

Conclusion

Patients with increased CIMT are considerably more likely to have NAFLD. Large prospective investigations are required to corroborate these findings and their prognostic significance, along with the effectiveness of the available interventions.

Metabolic dysfunction associated fatty liver disease identifies subjects with cardiovascular risk better than non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Cardiovascular disease (CVD) is the main cause of mortality in subjects with non-alcoholic fatty liver disease (NAFLD). We investigated the association between CVD risk and metabolic dysfunction-associated fatty liver disease (MAFLD) or NAFLD and the influence of significant liver fibrosis on the CVD risk.

METHODS

Subjects who underwent a comprehensive medical check-up were recruited (2014-2019). Significant liver fibrosis was defined using NAFLD fibrosis score, fibrosis-4 index, aspartate aminotransferase to platelet ratio index, or FibroScan-aspartate aminotransferase score. High probability of atherosclerotic CVD (ASCVD) was defined as ASCVD risk score > 10%.

RESULTS

Of the study population (n = 78 762), 27 047 (34.3%) and 24 036 (30.5%) subjects had MAFLD and NAFLD respectively. A total of 1084 (4.0%) or 921 (3.8%) subjects had previous CVD history in MAFLD or NAFLD subgroup respectively. The previous CVD history and high probability of ASCVD were significantly higher in MAFLD or NAFLD subgroup with significant liver fibrosis than in the other groups (all p < .001). In multivariable analysis, MAFLD was independently associated with previous CVD history after adjusting for confounders (adjusted odds ratio [aOR] = 1.10, p = .038), whereas NAFLD was not (all p > .05). MAFLD (aOR = 1.40) or NAFLD (aOR = 1.22) was independently associated with high probability of ASCVD after full adjustment respectively (all p < .001). Significant liver fibrosis was independently associated with previous CVD history and high probability of ASCVD after adjustment in MAFLD or NAFLD subgroup respectively (all p < .05).

CONCLUSION

MAFLD might better identify subjects with CVD risk than NAFLD. Fibrosis assessment might be helpful for detailed prognostication in subjects with MAFLD.

Endothelial Cell Dysfunction and Nonalcoholic Fatty Liver Disease (NAFLD): A Concise Review

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. It is strongly associated with obesity, type 2 diabetes (T2DM), and other metabolic syndrome features. Reflecting the underlying pathogenesis and the cardiometabolic disorders associated with NAFLD, the term metabolic (dysfunction)-associated fatty liver disease (MAFLD) has recently been proposed. Indeed, over the past few years, growing evidence supports a strong correlation between NAFLD and increased cardiovascular disease (CVD) risk, independent of the presence of diabetes, hypertension, and obesity. This implies that NAFLD may also be directly involved in the pathogenesis of CVD. Notably, liver sinusoidal endothelial cell (LSEC) dysfunction appears to be implicated in the progression of NAFLD via numerous mechanisms, including the regulation of the inflammatory process, hepatic stellate activation, augmented vascular resistance, and the distortion of microcirculation, resulting in the progression of NAFLD. Vice versa, the liver secretes inflammatory molecules that are considered pro-atherogenic and may contribute to vascular endothelial dysfunction, resulting in atherosclerosis and CVD. In this review, we provide current evidence supporting the role of endothelial cell dysfunction in the pathogenesis of NAFLD and NAFLD-associated atherosclerosis. Endothelial cells could thus represent a "golden target" for the development of new treatment strategies for NAFLD and its comorbid CVD.

Non-alcoholic fatty liver disease increases risk of carotid atherosclerosis and ischemic stroke: An updated meta-analysis with 135,602 individuals

BACKGROUND/AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with the development of cardiovascular disease. While existing studies have examined cardiac remodeling in NAFLD, there has been less emphasis on the development of carotid atherosclerosis and stroke. We sought to conduct a meta-analysis to quantify the prevalence, risk factors, and degree of risk increment of carotid atherosclerosis and stroke in NAFLD.

METHODS

Embase and Medline were searched for articles relating to NAFLD, carotid atherosclerosis, and stroke. Proportional data was analysed using a generalized linear mixed model. Pairwise meta-analysis was conducted to obtain odds ratio or weighted mean difference for comparison between patients with and without NAFLD.

RESULTS

From pooled analysis of 30 studies involving 7,951 patients with NAFLD, 35.02% (95% confidence interval [CI], 27.36-43.53%) had carotid atherosclerosis with an odds ratio of 3.20 (95% CI, 2.37-4.32; P<0.0001). Pooled analysis of 25,839 patients with NAFLD found the prevalence of stroke to be 5.04% (95% CI, 2.74-9.09%) with an odds ratio of 1.88 (95% CI, 1.23-2.88; P=0.02) compared to non-NAFLD. The degree of steatosis assessed by ultrasonography in NAFLD was closely associated with risk of carotid atherosclerosis and stroke. Older age significantly increased the risk of developing carotid atherosclerosis, but not stroke in NAFLD.

CONCLUSION

This meta-analysis shows that a stepwise increment of steatosis of NAFLD can significantly increase the risk of carotid atherosclerosis and stroke development in NAFLD. Patients more than a third sufferred from carotid atherosclerosis and routine assessment of carotid atherosclerosis is quintessential in NAFLD.

Comorbidities Are Associated with Fibrosis in NAFLD Subjects: A Nationwide Study (NASH-CO Study)

BACKGROUND

The relationship between the severity of NAFLD and extra-hepatic events such as cardiovascular disease (CVD), extra-hepatic cancer (EHC) or chronic kidney diseases (CKD) has not been clearly investigated in the general population.

AIMS

The aim of this study was to assess whether the severity of fibrosis in NAFLD subjects was associated with extra-hepatic diseases based on noninvasive markers in a large population-based cohort.

METHODS

The study population included a cohort of 118,664 participants from the nationwide CONSTANCES cohort. After excluding individuals with excessive alcohol consumption and other causes of liver disease, 102,344 were included. The noninvasive diagnosis of NAFLD and fibrosis was performed using a combination of the Fatty Liver Index (FLI) and the Forns Index. The history of CVD or EHC was recorded by a physician, and CKD was defined by a glomerular filtration rate < 60 ml/mn.

RESULTS

The prevalence of NAFLD (FLI > 60) was 18.2%, 10% with mild fibrosis (Forns Index < 4.2), 7.7% with intermediate fibrosis (Forns Index 4.2-6.9), and 0.4% with advanced fibrosis (Forns Index > 6.9). The prevalence of CVD, EHC, or CKD increased significantly with the severity of fibrosis (p < 0.0001). When adjusted for demographic, metabolic risk factors, and smoking, NAFLD with intermediate or advanced fibrosis remained associated with CVD (OR 1.36, p < 0.0001 and OR 3.07, p < 0.0001, respectively), EHC (OR 1.24, p = 0.001 and OR 1.64, p = 0.004, respectively), and CKD (OR 1.18, p = 0.03 and OR 2.09, p < 0.0001, respectively).

CONCLUSIONS

In a large adult population-based cohort, there is a dose-dependent relationship between the severity of fibrosis and CVD, EHC, or CKD in NAFLD subjects.

Endothelial Dysfunction in Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Individuals with nonalcoholic fatty liver disease (NAFLD) are characterized by increased cardiovascular risk. Endothelial dysfunction, a mechanism implicated in those processes, may constitute the missing link in this interaction. Therefore, this systematic review and meta-analysis aims to evaluate the association of endothelial dysfunction, assessed by flow-mediated dilation (FMD) of the brachial artery, with NAFLD. We conducted a systematic literature search for studies assessing the difference in FMD between patients with NAFLD and controls. Exclusion criteria consisted of preclinical studies, studies in children/adolescents, no FMD assessment, and the absence of an NAFLD/control group. The database search identified 96 studies. Following the application of the exclusion criteria, 22 studies were included in the meta-analysis (NAFLD: 2164 subjects; control: 3322 subjects). Compared with controls, patients with NAFLD had significantly lower FMD% values (SMD: −1.37, 95% CI −1.91 to −0.83, p < 0.001, I2: 98%). Results remained unaffected after exclusion of any single study. Subgroup analysis revealed significantly decreased FMD in NAFLD subjects diagnosed with liver ultrasound or liver biopsy compared with method combination or other methods, while no differences were observed according to the chosen cuff inflation threshold, the presence of a significant difference in obesity measures between the groups, or the type of the control group (age- and sex-matched vs. other). Funnel plot asymmetry was not observed. Finally, compared with patients with pure steatosis, individuals with nonalcoholic steatohepatitis had significantly lower FMD (SMD: −0.81, 95% CI −1.51 to −0.31, p = 0.003, I2: 81%). In conclusion, FMD of the brachial artery, indicative of endothelial dysfunction, was significantly reduced in subjects with nonalcoholic fatty liver disease. Patients with nonalcoholic steatohepatitis might be facing a more pronounced endothelial impairment.

Coagulation and Endothelial Dysfunction Associated with NAFLD: Current Status and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is closely related to insulin resistance, type 2 diabetes mellitus and obesity. It is considered a multisystem disease and there is a strong association with cardiovascular disease and arterial hypertension, which interfere with changes in the coagulation system. Coagulation disorders are common in patients with hepatic impairment and are dependent on the degree of liver damage. Through a review of the literature, we consider and discuss possible disorders in the coagulation cascade and fibrinolysis, endothelial dysfunction and platelet abnormalities in patients with NAFLD.

The Coexistence of Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus

The incidence of nonalcoholic fatty liver disease (NAFLD) is growing worldwide. Epidemiological data suggest a strong relationship between NAFLD and T2DM. This is associated with common risk factors and pathogenesis, where obesity, insulin resistance and dyslipidemia play pivotal roles. Expanding knowledge on the coexistence of NAFLD and T2DM could not only protect against liver damage and glucotoxicity, but may also theoretically prevent the subsequent occurrence of other diseases, such as cancer and cardiovascular disorders, as well as influence morbidity and mortality rates. In everyday clinical practice, underestimation of this problem is still observed. NAFLD is not looked for in T2DM patients; on the contrary, diagnosis for glucose metabolism disturbances is usually not performed in patients with NAFLD. However, simple and cost-effective methods of detection of fatty liver in T2DM patients are still needed, especially in outpatient settings. The treatment of NAFLD, especially where it coexists with T2DM, consists mainly of lifestyle modification. It is also suggested that some drugs, including hypoglycemic agents, may be used to treat NAFLD. Therefore, the aim of this review is to detail current knowledge of NAFLD and T2DM comorbidity, its prevalence, common pathogenesis, diagnostic procedures, complications and treatment, with special attention to outpatient clinics.

NAFLD as a continuous driver in the whole spectrum of vascular disease

Vascular disease is the prime determinant to cardiovascular morbidities and mortalities, which comprises the early vascular damage and subsequent cardiovascular events. Non-alcohol Fatty Liver Disease (NAFLD) is a systemic metabolic disorder that drives the progression of vascular disease through complex interactions. Although a causal relationship between NAFLD and cardiovascular disease (CVD) has not been established, a growing number of epidemiological studies have demonstrated an independent association between NAFLD and early vascular disease and subsequent cardiovascular events. In addition, mechanistic studies suggest that NAFLD initiates and accelerates vascular injury by increasing systemic inflammation and oxidative stress, impairing insulin sensitivity and lipid metabolism, and modulating epigenetics, the intestinal flora and hepatic autonomic nervous system; thus, NAFLD is a putative driving force for CVD progression. In this review, we summarize the clinical evidence supporting the association of NAFLD with subclinical vascular disease and cardiovascular events and discuss the potential mechanisms by which NAFLD promotes the progression of vascular disease.

Risk factors and characteristics associated with nonalcoholic fatty liver disease in patients with ischemic colitis

BACKGROUND

Ischemic colitis (IC) was investigated to be associated with dyslipidemia and subcutaneous adipose tissue. Nonalcoholic fatty liver disease (NAFLD) is associated with ischemic diseases such as coronary heart disease, ischemic stroke. But there is a paucity of data regarding the association between NAFLD and IC. NAFLD may be associated with the treatment and prognosis of IC. We investigated risk factors and characteristics associated with NAFLD in patients with IC.

METHODS

Patients with IC (NAFLD: 34 and controls: 81) from Zhongnan Hospital were investigated retrospectively from January 2012 to December 2018. Clinical data were compared by chi-square tests or independent samples T-tests. Binary logistic regressions and Kaplan-Meier analysis were performed to evaluate risk factors and prognosis, respectively.

RESULTS

NAFLD was diagnosed in 28.19% patients with IC. In the logistic regression analysis, hypertension [odds ratio (OR) 3.523; P = 0.019], elevated alanine aminotransferase (ALT) (OR 6.278; P = 0.048), elevated triglyceride (OR 4.667; P = 0.003) and increased weight (OR 1.055; P = 0.039) were risk factors of NAFLD in patients with IC. Patients with NAFLD were more likely to require the vasodilators (P = 0.011) and get a relapse of IC (P = 0.011).

CONCLUSION

NAFLD was found in 28.19% of patients with IC. Hypertension, increased weight, elevated ALT and triglyceride are independent predictors of NAFLD in patients with IC. NAFLD in patients with IC is associated with a greater probability of requiring for the vasodilators. NAFLD in IC and period of bowel rest are risk factors for the recurrence of IC.

Fatty Liver Index is Positively Associated with Arterial Stiffness in a Chinese Cohort Undergoing Health Assessment

Objective

Nonalcoholic fatty fiver disease (NAFLD) is a metabolic liver injury closely related to insulin resistance. Fatty liver index (FLI) can be used as a surrogate marker and is a validated index for NAFLD. This study aimed to explore the relationship between FLI and arterial stiffness in a Chinese population.

Methods

From December 2017 to March 2019, 402 inpatients (mean age 51.12 ± 11.95 years) were recruited for cardiovascular disease screening at Ruijin Hospital North, Shanghai. Measurement of brachial systolic, diastolic, mean, and pulse pressure was done with cuff sphygmomanometry and carotid-femoral pulse wave velocity (cfPWV) was measured (SphygmoCor) to assess arterial stiffness.

Results

Subjects were divided into three groups according to their FLI < 30, normal; 30–59, intermediate fatty liver index; ≥ 60, NAFLD. The proportion of subjects with hepatic steatosis (FLI ≥ 60), intermediate FLI (30–59), and no steatosis (FLI < 30) was 34.4%, 31.8%, and 33.8%, respectively. The male population (53.9%) had significantly higher FLI levels (p < 0.05). Subjects with FLI ≥ 60 had higher cfPWV (8.41 ± 1.77 m/s) than those with FLI < 30 (7.81 ± 1.83 m/s; p = 0.006). cfPWV was positively correlated with logFLI (r = 0.168, p = 0.001). After adjusting for age, sex, body mass index, mean arterial blood pressure, glucose, cholesterol, heart rate, and glomerular filtration rate (eGFR), FLI remained positively associated with cfPWV (β = 0.097, p = 0.024).

Conclusion

cfPWV, as a measure of arterial stiffness, is higher in the NAFLD group when compared to that in normal groups. Fatty liver index is positively associated with arterial stiffness in a Chinese population.

Liver fibrosis is associated with carotid atherosclerosis in patients with liver biopsy-proven nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is related to subclinical atherosclerosis. However, whether the severity of the disease (or which histopathological component) is associated with subclinical atherosclerosis remains controversial. This study aimed to investigate the association between the histopathological severity of NAFLD and carotid intima-media thickness (CIMT) in Japanese patients with liver biopsy-proven NAFLD. Maximum-CIMT (max-CIMT) was measured as an index of carotid atherosclerosis in 195 biopsy-proven NAFLD patients. A significant association was observed between the severity of fibrosis (but not steatosis, inflammation, and ballooning) and max-CIMT. Older age, male gender, hypertension, and advanced fibrosis were independently linked to max-CIMT ≥ 1.2 mm. The prevalence of max-CIMT ≥ 1.2 mm was significantly higher in the advanced fibrosis group than in the non-advanced fibrosis group (75.4% versus 44.0%; p < 0.01). Non-invasive liver fibrosis markers and scoring systems, including fibrosis-4 index, NAFLD fibrosis score, hyaluronic acid, and Wisteria floribunda agglutinin positive Mac-2-binding protein, demonstrated that the diagnostic performance for max-CIMT ≥ 1.2 mm was similar to that of biopsy-based fibrosis staging. In conclusion, advanced fibrosis is significantly and independently associated with high-risk CIMT. Non-invasive fibrosis markers and scoring systems could help estimate the risk of atherosclerosis progression in patients with NAFLD.

Significantly higher atherosclerosis risks in patients with obstructive sleep apnea and non-alcoholic fatty liver disease

INTRODUCTION

There is limited data on the relationship between Obstructive Sleep Apnea (OSA) and Non-Alcoholic Fatty Liver Disease (NAFLD), each associated with increased cardiovascular risk. This study aimed to determine the relationships between severity of OSA, degree of steatosis in NAFLD and cardiovascular risk via CIMT and atherosclerosis markers ie intracellular adhesion molecule-1 (ICAM-1) an Lipoprotein-a (Lp(a)) in a group of patients with OSA.

MATERIALS AND METHODS

This was a cross-sectional, single center study. A total of 110 subjects between 18 to 65 years of age and diagnosed with OSA following sleep study examinations were recruited. Exclusion criteria included seropositive Hepatitis B or Hepatitis C, and significant alcohol intake.

RESULT

The prevalence of NAFLD was 81.8%. The mean CIMT (0.08±0.03 vs 0.06±0.01 cm, p = 0.001), ICAM-1 (334.53±72.86 vs 265.46±102.92 ng/mL, p = 0.001) and Lp(a) (85.41±52.56 vs 23.55±23.66 nmol/L, p<0.001) were significantly higher in the NAFLD group compared to the non-NAFLD group. Comparisons between the different groups showed significantly increasing levels of CIMT, ICAM-1 and Lp(a), lowest within the non-NAFLD, followed by the NAFLD 1 and NAFLD 2+3 groups. There was a significant positive correlation between degree of steatosis and the severity of OSA (r = 0.453, p<0.001). Logistic regression analysis revealed that patients with apnea/hypopnea index (AHI) of >30 were 52.77 (CI 6.34, 439.14) times more likely to have NAFLD compared to those with mild AHI (p<0.001).

CONCLUSION

The prevalence of NAFLD is alarmingly high in this group of OSA patients. The degree of steatosis in patients with NAFLD was significantly correlated with severity of OSA, CIMT measurements, ICAM-1 and Lp(a). Our findings underscore screening for NAFLD in patients with OSA to ensure prompt risk stratification and management.

Endothelial Progenitor Cells Dysfunctions and Cardiometabolic Disorders: From Mechanisms to Therapeutic Approaches

Metabolic syndrome (MetS) is a cluster of several disorders, such as hypertension, central obesity, dyslipidemia, hyperglycemia, insulin resistance and non-alcoholic fatty liver disease. Despite health policies based on the promotion of physical exercise, the reduction of calorie intake and the consumption of healthy food, there is still a global rise in the incidence and prevalence of MetS in the world. This phenomenon can partly be explained by the fact that adverse events in the perinatal period can increase the susceptibility to develop cardiometabolic diseases in adulthood. Individuals born after intrauterine growth restriction (IUGR) are particularly at risk of developing cardiovascular diseases (CVD) and metabolic disorders later in life. It has been shown that alterations in the structural and functional integrity of the endothelium can lead to the development of cardiometabolic diseases. The endothelial progenitor cells (EPCs) are circulating components of the endothelium playing a major role in vascular homeostasis. An association has been found between the maintenance of endothelial structure and function by EPCs and their ability to differentiate and repair damaged endothelial tissue. In this narrative review, we explore the alterations of EPCs observed in individuals with cardiometabolic disorders, describe some mechanisms related to such dysfunction and propose some therapeutical approaches to reverse the EPCs dysfunction.

Influence of cardiometabolic comorbidities on myocardial function, infarction, and cardioprotection: Role of cardiac redox signaling

The morbidity and mortality from cardiovascular diseases (CVD) remain high. Metabolic diseases such as obesity, hyperlipidemia, diabetes mellitus (DM), non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) as well as hypertension are the most common comorbidities in patients with CVD. These comorbidities result in increased myocardial oxidative stress, mainly from increased activity of nicotinamide adenine dinucleotide phosphate oxidases, uncoupled endothelial nitric oxide synthase, mitochondria as well as downregulation of antioxidant defense systems. Oxidative and nitrosative stress play an important role in ischemia/reperfusion injury and may account for increased susceptibility of the myocardium to infarction and myocardial dysfunction in the presence of the comorbidities. Thus, while early reperfusion represents the most favorable therapeutic strategy to prevent ischemia/reperfusion injury, redox therapeutic strategies may provide additive benefits, especially in patients with heart failure. While oxidative and nitrosative stress are harmful, controlled release of reactive oxygen species is however important for cardioprotective signaling. In this review we summarize the current data on the effect of hypertension and major cardiometabolic comorbidities such as obesity, hyperlipidemia, DM, NAFLD/NASH on cardiac redox homeostasis as well as on ischemia/reperfusion injury and cardioprotection. We also review and discuss the therapeutic interventions that may restore the redox imbalance in the diseased myocardium in the presence of these comorbidities.

The pivotal role of heme Oxygenase-1 in reversing the pathophysiology and systemic complications of NAFLD

The pathogenesis and molecular pathways involved in non-alcoholic fatty liver disease (NAFLD) are reviewed, as well as what is known about mitochondrial dysfunction that leads to heart disease and the progression to steatohepatitis and hepatic fibrosis. We focused our discussion on the role of the antioxidant gene heme oxygenase-1 (HO-1) and its nuclear coactivator, peroxisome proliferator-activated receptor-gamma coactivator (PGC1-α) in the regulation of mitochondrial biogenesis and function and potential therapeutic benefit for cardiac disease, NAFLD as well as the pharmacological effect they have on the chronic inflammatory state of obesity. The result is increased mitochondrial function and the conversion of white adipocyte tissue to beige adipose tissue ("browning of white adipose tissue") that leads to an improvement in signaling pathways and overall liver function. Improved mitochondrial biogenesis and function is essential to preventing the progression of hepatic steatosis to NASH and cirrhosis as well as preventing cardiovascular complications.

Non-alcoholic fatty liver disease: A growing public health problem in Turkey

Non-alcoholic fatty liver disease (NAFLD) is histologically classified as either non-alcoholic fatty liver or non-alcoholic steatohepatitis (NASH). NASH is the progressive subtype of NAFLD. Individuals with NASH are at significant risk of developing hepatic fibrosis, cirrhosis, hepatocellular carcinoma, and liver-related and all-cause mortality. NAFLD is closely associated with obesity, type 2 diabetes mellitus (T2DM), metabolic syndrome, and cardiovascular events. Its prevalence is estimated to be above 30% in Turkey; and recent studies confirm this estimate. According to these studies, the prevalence of NAFLD in Turkey is between 48.3% and 60.1%. Currently, Turkey can be considered a risky region in terms of NAFLD burden as it is the most obese country in Europe with an obesity prevalence of 32.1% according to the 2016 World Health Organization data. Moreover, along with the increasing prevalence of obesity and T2DM in Turkey, the burden of NAFLD is estimated to increase in the upcoming decade. Despite the growing burden, we lack well-designed systemic studies that investigate NAFLD and its marked histological severity. In this review, we present studies on the burden of NAFLD and NASH, the natural history of NAFLD, and its association with other systemic diseases conducted with Turkish populations.

Cardiovascular Risk in Fatty Liver Disease: The Liver-Heart Axis-Literature Review

According to the World Health Organization, cardiovascular disease (CVD) remains the leading cause of death worldwide, accounting for approximately 18 million deaths per year. Nevertheless, the worldwide prevalence of metabolic diseases, such as type 2 diabetes mellitus, obesity, and non-alcoholic fatty liver disease (NAFLD), also known to be common risk factors for CVD, have dramatically increased over the last decades. Chronic alcohol consumption is a major cause of chronic liver diseases (CLD) as well as being a major health care cost expenditure accounting for the spending of tremendous amounts of money annually. NAFLD has become one of the major diseases plaguing the world while standing as the most common cause of liver disease in the Western countries by representing about 75% of all CLD. Currently, the most common cause of death in NAFLD remains to be CVD. Several mechanisms have been suggested to be responsible for associating FLD with CVD through several mechanisms including low-grade systemic inflammation, oxidative stress, adipokines, endoplasmic reticulum stress, lipotoxicity and microbiota dysbiosis which may also be influenced by other factors such as genetic and epigenetic variations. Despite of all this evidence, the exact mechanisms of how FLD can causally contribute to CVD are not fully elucidated and much remains unknown. Moreover, the current literature supports the increasing evidence associating FLD with several cardiovascular (CV) adverse events including coronary artery disease, increased subclinical atherosclerosis risk, structural alterations mainly left ventricular hypertrophy, increased epicardial fat thickness, valvular calcifications including aortic valve sclerosis and mitral annular calcification and functional cardiac modifications mainly diastolic dysfunction in addition to cardiac arrhythmias such as atrial fibrillation and ventricular arrythmias and conduction defects including atrioventricular blocks and bundle branch blocks. Patients with FLD should be evaluated and managed accordingly in order to prevent further complications. Possible management methods include non-pharmacological strategies including life style modifications, pharmacological therapies as well as surgical management. This review aims to summarize the current state of knowledge regarding the pathophysiological mechanisms linking FLD with an increased CV risk, in addition to associated CV adverse events and current management modalities.

Serum Ferritin level, microalbuminuria and non-alcoholic fatty liver disease in type 2 diabetic patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) was considered one of the most common causes of chronic liver disease and is considered the hepatic manifestation of type 2 diabetes mellitus (T2DM). The factors that lead to marked fibrosis and liver cell injury in NAFLD are still remaining undiscovered.

PATIENTS AND METHODS

This study included (40) type 2 diabetic patients with NAFLD and (40) diabetic patients without NAFLD beside 15 healthy persons as a control group. All of them were subjected to full history taking, thorough clinical examination with especial stress on body weight (BW), height, body mass index (BMI), waist-hip ratio, blood pressure. Laboratory tests included serum total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL) and high-density lipoprotein (HDL), fasting blood glucose (FBG) and 2-h postprandial blood glucose (PBG), serum Ferritin and urine microalbuminuria (MAU).

RESULTS

Duration of diabetes, BW, BMI and blood pressure were significantly higher in NAFLD group (P = 0.001). FBG, PBG, TC, TG, LDL, serum Ferritin and MAU were significantly increased in NAFLD group with significant difference between two studied groups as regard HDL. There was a highly significant correlation between serum Ferritin with BW, BMI, duration of diabetes, TC, TG, LDL and MAU. There was a significant correlation between serum Ferritin with age, waist hip ratio, duration of diabetes, SBP, FBG, PBG and HDL. There was a significant correlation between MAU and age, weight, BMI, waist hip ratio, duration of diabetes, DBP, FBG TC, TG, LDL and HDL.

CONCLUSION

NAFLD is a common liver disorder in diabetic patients. NAFLD is significantly associated with microalbuminuria and elevated serum Ferritin.

Acute Endothelial Benefits of Fat Restriction over Carbohydrate Restriction in Type 2 Diabetes Mellitus: Beyond Carbs and Fats

Background: Cardiovascular diseases (CVD) are the major cause of mortality in type 2 diabetes patients (T2DM). The causes are embedded in a complex interplay between excess body fat, insulin resistance and serum lipid anomalies. Endothelial homeostasis is strongly affected by this pathogenic network. Even though metabolic changes and weight loss improve vascular endothelial function, the effect of different dietary approaches is still uncertain for type 2 diabetes patients. Objective: We aimed to compare the acute effects of a hypocaloric very low carbohydrate (VLC) diet versus a hypocaloric low fat (LF) diet on flow mediated dilation (FMD), intrahepatic lipid (IHL) accumulation and visceral adipose tissue as independent risk factors of CVD in T2DM patients. Design: 36 T2DM patients (age 63 ± 8 years, 60% females) were randomly assigned to the VLC diet (4–10% of total energy intake (E)) or to the LF diet (<30% E) for 3 weeks. Endothelial function was assessed by the flow mediated dilation (FMD) method. Adipose tissue depots and IHL were determined by magnetic resonance. Results: Both dietary strategies reduced body weight, body fat content and IHL. Unexpectedly, the LF group experienced significantly greater enhancement of FMD, compared to the VLC group. The FMD showed a positive correlation with protein intake and fat intake in the LF group, while it revealed a negative correlation with protein intake in the VLC diet group. Conclusions: Reduction of total and hepatic adiposity was shown to be successful using either the VLC or LF hypocaloric diets, however, improvements in FMD may be related to the interplay of fat and protein intake.

Ideal cardiovascular health associated with fatty liver: Results from a multi-ethnic survey

BACKGROUND AND AIMS

Little is known about the role of liver enzymes as predictors of non-liver-related morbidity and mortality. The ideal cardiovascular health (CVH) score proposed by the American Heart Association (AHA) can be used to predict mortality and morbidity. We investigated the association of the CVH score with liver enzymes and the risk of non-alcoholic fatty liver disease (NAFLD) among US adults.

METHODS

By using the National Health and Nutrition Examination Survey database (cross-sectional), the CVH score was calculated as meeting ideal levels of the following components: 4 behaviors (smoking, body mass index, physical activity and diet adherence) and 3 factors (total cholesterol, blood pressure and fasting glucose).

RESULTS

Individuals with a higher CVH score ("better CVH") had a more favorable profile of liver biomarkers. Adjusted (for age, gender, race, poverty to income ratio, education, marital status and alcohol intake) linear regression indicated significant and negative associations between liver biomarkers and CVH score: (β = -0.069, p < 0.001) for alanine aminotransferase, (β = -0.095, p < 0.001), aspartate aminotransferase, (β = -0.067, p < 0.001), alkaline phosphatase and (β = -0.125, p < 0.001) and fatty liver index. In the logistic regression, with the same confounders, individuals with a higher CVH score had 12% less likelihood of NAFLD compared with those with a lower score. Furthermore, each CVH metric separately was inversely linked to the risk of NAFLD.

CONCLUSIONS

For the first time among US adults, our findings shed light on the role CVH on liver biomarkers.

Non-alcoholic fatty liver disease-From the cardiologist perspective

Non-alcoholic fatty liver disease (NAFLD) includes a range of disorders characterized by excess accumulation of triglycerides within the liver. While simple steatosis may be clinically stable, non-alcoholic steatohepatitis (NASH) can be progressive. Inflammation is believed to be the driving force behind NASH and the progression to fibrosis and subsequent cirrhosis. NAFLD is globally considered a significant health concern not only because of its incidence but also because of its economic impact. The fact that NAFLD is associated with cardiovascular disease is widely recognized, as well as the fact that NAFLD patient mortality rises when such an association is present. In particular, NAFLD is associated with coronary and carotid atherosclerosis, endothelial dysfunction and arterial rigidity, ventricles function, valves morphology, congestive heart failure, and arrhythmias (especially atrial fibrillation). Additionally, the hypercoagulability status in NAFLD patient may be suggested by the presence of inflammatory and coagulation markers. In order to differentiate between milder forms and the more severe ones that necessitate aggressive therapy, individualized risk scores may be used. This narrative review will analyze and interpret the papers published in PubMed in the last 16 years, in an attempt to expand our understanding of the NASH as a possible cardiovascular risk factor.

Association between nonalcoholic fatty liver disease and subclinical atherosclerosis: a cross-sectional study on population over 40 years old

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) refers to fatty infiltration of liver in the absence of excessive alcohol abuse. However, the problem that whether NAFLD is correlated with subclinical atherosclerosis assessed by carotid intima-media thickness (CIMT) and brachial-ankle pulse wave velocity (ba-PWV) remains a source of controversy. This can be attributed to the differences in diagnosis methods, population ethnicity, sampling size and bias. This study aimed to further investigate the association of NAFLD with subclinical atherosclerosis.

METHODS

A cross-sectional study was carried out in the current study on population aged over 40 years derived from Kailuan community-based prospective study among Chinese adults from June 2010 to June 2011. NAFLD was evaluated through ultrasonography and histories of alcohol consumption. Clinical parameters and medical histories of patients were collected in the manner of interview performed by trained investigators using the standardized questionnaires. The biochemical parameters were analyzed at the central laboratory. CIMT and ba-PWV of each patient were measured. Multivariate logistic regression was used to analyze the associations of NAFLD with subclinical atherosclerosis assessed by CIMT or ba-PWV.

RESULTS

A total of 4112 participants aged over 40 years were enrolled from Kailuan cohort, including 2229 men and 1883 women. The overall prevalence of NAFLD was 38.2% in the total population. Statistically significant differences were found in CIMT (P < 0.0001) and ba-PWV (P = 0.0007) according to the presence of NAFLD. It is notably that the multivariate logistic regression revealed NAFLD was independently associated with elevated CIMT after adjusting the conventional cardiovascular and metabolic risk factors (OR = 1.663, 95% CI = 1.391-1.989, P < 0.0001). In addition, NAFLD was also found to be positively associated with elevated ba-PWV after adjusting age, gender, BMI, current smoking and regular exercising (OR = 1.319, 95% CI = 1.072-1.624, P = 0.0089).

CONCLUSIONS

Our findings suggest that NAFLD is remarkably correlated with subclinical atherosclerosis, which should be strongly advised to engage in the preventive strategies for cardiovascular diseases (CVDs).

The influence of NAFLD on the risk of atherosclerosis and cardiovascular diseases

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in developed countries and is associated with obesity, dyslipidaemia, diabetes, and metabolic syndrome. Atherosclerosis and cardiovascular diseases are also highly prevalent in this group of patients, due to the presence of shared risk factors. The incidences of coronary artery calcification, hypertension, aortic valve sclerosis, diastolic dysfunction, atherosclerotic plaques, and increased carotid intima-media thickness were more common in patients with NAFLD than in those without. The present paper reviews the medical literature concerning the association between NAFLD and cardiovascular events.

Ideal cardiovascular health predicts lower risk of abnormal liver enzymes levels in the Chilean National Health Survey (2009-2010)

High levels of gamma glutamyltransferase (gamma-GT) and alanine aminotransferase (ALT), as well as fatty liver index (FLI) has been associated with higher cardiovascular disease risk factors in adults. The aim of this study was to examine the relationship between gamma-GT, ALT, and fatty liver index FLI levels across a gradient number of ideal cardiovascular health metrics in a representative sample of adults from the Chilean National Health Survey 2009-2010. Data from 1,023 men and 1,449 women (≥ 15 years) from the Chilean Health Survey 2009-2010 were analyzed. Ideal cardiovascular health was defined as meeting ideal levels of the following components: four behaviours (smoking, body mass index, physical activity and diet adherence) and three factors (total cholesterol, blood pressure and fasting glucose). Adults were grouped into three categories according to their number of ideal cardiovascular health metrics: ideal (5-7 metrics), intermediate (3-4 metrics), and poor (0-2 metrics). Blood levels of gamma-GT and ALT were measured and the FLI was calculated. A higher number of ideal cardiovascular health index metric was associated with lower gamma-GT, ALT and FLI (p from trend analysis <0.001). Also, adults meeting at least 3-4 metrics were predicted less likely to have prevalence of abnormal levels of gamma-GT and FLI (p<0.001) compared to adults who met only 0-2 metrics. These findings reinforce the usefulness of the ideal cardiovascular health metrics proposed by the American Heart Association as a tool to identify target subjects and promote cardiovascular health in South-American adults.

Evaluation of endothelial dysfunction in patients with nonalcoholic fatty liver disease: Association of selenoprotein P with carotid intima-media thickness and endothelium-dependent vasodilation

BACKGROUND

In patients with NAFLD, there is an increased risk of cardiovascular disease (CVD). Selenoprotein P (SelP), a hepatokine, is associated with insulin resistance (IR) and serum SelP was found to be elevated in patients with NAFLD.

AIM

This study aimed to determine the risk of CVD in NAFLD patients and the association of serum SelP levels with this NAFLD related CVD risk.

METHODS

Ninety-three patients with NAFLD and 37 healthy controls were included in the study. Complete blood count, C-reactive protein (CRP), fasting glucose, serum lipid levels, and SelP levels were tested from fasting blood samples. Moreover, body mass index (BMI), HOMA-IR, carotid intima-media thickness (cIMT) and flow-mediated dilatation (FMD) were measured.

RESULTS

In patients with NAFLD, the FMD ratio was significantly lower than in controls (P=0.027). cIMT measurements were similar in both groups (P=0.996). Serum SelP levels were significantly higher than controls (P<0.001). SelP levels were significantly correlated with BMI, fasting glucose, LDL-cholesterol and HOMA-IR (r=0.395, P<0.001; r=0.322, P=0.002; r=0.353, P<0.001; r=0.521, P<0.001, respectively). Also, SelP levels were significantly lower and correlated with FMD (r=-0.674, P<0.001). SelP, ESR and CRP were significantly higher (P<0.05) and FMD ratios were significantly lower (P<0.05) in patients with nonalcoholic steatohepatitis (NASH) when compared to patients with simple steatosis.

CONCLUSION

These results suggest that in young NAFLD patients without additional comorbidities, there is an increased risk of CVD. FMD may be a better predictor for assessment of CVD risk when compared with cIMT. We assume that there could also be an important role of SelP in the pathogenesis of NASH.

Nonalcoholic fatty liver disease associated with metabolic syndrome: Influence of liver fibrosis stages on characteristics of very low-density lipoproteins

BACKGROUND

We evaluated possible changes in VLDLcharacteristics, and metabolic related factors, in MetS-associated NAFLD and accompanying liver fibrosis.

METHODS

We studied 36 MetS patients with biopsy-proven NAFLD (MetS+NAFLD) and 24 MetS without ultrasound NAFLD evidence. Further, MetS+NAFLD was sub-divided according to fibrosis stage into, non-to-moderate (F0-F2, n=27) and severe (F3-F4, n=9) fibrosis. We measured: lipid profile, VLDL composition and size (size exclusion-HPLC), CETP and lipoprotein lipase (LPL) activities and adiponectin. Additionally, in MetS+NAFLD type IV collagen 7S domain was measured.

RESULTS

MetS+NAFLD showed increased VLDL-mass, VLDL particle number, VLDL-triglyceride% and large VLDL-% (p<0.04). CETP activity tended to increase in MetS+NAFLD (p=0.058), while LPL activity was unchanged. Moreover, in MetS+NAFLD, adiponectin was decreased (p<0.001), and negatively correlated with VLDL-mass and VLDL particle number (p<0.05), independently of insulin-resistance. Within MetS+NAFLD group, despite greater insulin-resistance, patients with severe fibrosis showed lower plasma triglycerides, VLDL-mass, VLDL-triglyceride%, large VLDL-% and CETP activity (p<0.05), while type IV collagen was increased (p=0.009) and inversely correlated with large VLDL-% (p=0.045).

CONCLUSIONS

In MetS, NAFLD is associated with larger and triglyceride over-enriched circulating VLDLs, of greater atherogenicity. However, when NAFLD progresses to severe fibrosis, circulating VLDL features apparently improved, probably due to early alterations in hepatic synthetic function.

Nonalcoholic fatty liver disease: implications for cardiovascular risk

Nonalcoholic fatty liver disease (NAFLD) is a growing epidemic in the USA affecting ∼30% of the population. It has been closely linked to metabolic syndrome and type 2 diabetes, with strong implications for cardiovascular disease (CVD). This review focuses on the relationship between NAFLD and CVD and the proposed interactions interlinking these two diseases. This appraisal also discusses treatments targeting NAFLD in the context of CVD. NAFLD is a multisystem disease and ultimately the goals of therapy are to ameliorate CVD and prevent coronary artery disease morbidity and mortality.

Dimethylarginine Dimethylaminohydrolase 1 Protects Against High-Fat Diet-Induced Hepatic Steatosis and Insulin Resistance in Mice

AIMS

High plasma concentrations of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, are associated with hepatic dysfunction in patients with nonalcoholic fatty liver disease (NAFLD). However, it is unknown whether ADMA is involved in the pathogenesis of NAFLD. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is an enzyme that degrades ADMA. In this study, we used Ddah1^-/- mice to investigate the effects of the ADMA/DDAH1 pathway on high-fat diet (HFD)-induced hepatic steatosis.

RESULTS

After HFD feeding for 20 weeks, Ddah1^-/- mice were more obese and had developed more severe hepatic steatosis and worse insulin resistance compared with wild-type (WT) mice. In the livers of HFD-fed mice, loss of DDAH1 resulted in higher levels of lipogenic genes, lower expression of β-oxidation genes, and greater induction of oxidative stress, endoplasmic reticulum stress, and inflammation than in the WT livers. Furthermore, ADMA treatment in HepG2 cells led to oxidative stress and steatosis, whereas overexpression of DDAH1 attenuated palmitic acid-induced steatosis, oxidative stress, and inflammation. Innovation and Conclusion: Our results provide the first direct evidence that the ADMA/DDAH1 pathway has a marked effect on hepatic lipogenesis and steatosis induced by HFD feeding. Our findings suggest that strategies to increase DDAH1 activity in hepatocytes may provide a novel approach to attenuate NAFLD development. Antioxid. Redox Signal. 26, 598-609.

Non-alcoholic fatty liver disease fibrosis score and preclinical vascular damage in morbidly obese patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is strongly related with enhanced morbidity and mortality from cardiovascular disease. In obese patients with both NAFLD and features of the metabolic syndrome, the cardiovascular risk is further increased.

AIM

The aim of this study is to investigate the relationship between severity of liver fibrosis evaluated by NAFLD fibrosis score (NAFLD-FS), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), other obesity-related markers and preclinical atherosclerosis in morbidly obese patients with previously diagnosed NAFLD.

METHODS

Laboratory parameters, visceral fat area (VFA), flow-mediated dilatation (FMD), intima-media thickness (IMT), HOMA-IR and NAFLD-FS were determined in 196 morbidly obese patients.

RESULTS

Patients with higher NAFLD-FS or HOMA-IR show higher left max-IMT and lower FMD (p<0.001). VFA and NAFLD-FS, but not HOMA-IR, were independent predictors of reduced FMD (respectively β -0.268, p=0.001 and β -0.165, p=0.039, p of the model<0.001) and increased left max-IMT (respectively β 0.165, p=0.031 and β 0.301, p<0.001, p of the model<0.001).

CONCLUSIONS

In morbidly obese patients, NAFLD-FS correlates with markers of early vascular damage. NAFLD-FS, easier to obtain than VFA, seems to be a better score than HOMA-IR to categorize such subjects who are potentially at risk of future cardiovascular events.

MCD diet-induced steatohepatitis is associated with alterations in asymmetric dimethylarginine (ADMA) and its transporters

Using an experimental model of NASH induced by a methionine-choline-deficient (MCD) diet, we investigated whether changes occur in serum and tissue levels of asymmetric dimethylarginine (ADMA). Male Wistar rats underwent NASH induced by 8-week feeding with an MCD diet. Serum and hepatic biopsies at 2, 4 and 8 weeks were taken, and serum enzymes, ADMA and nitrate/nitrite (NOx), were evaluated. Hepatic biopsies were used for mRNA and protein expression analysis of dimethylarginine dimethylaminohydrolase-1 (DDAH-1) and protein methyltransferases (PRMT-1), enzymes involved in ADMA metabolism and synthesis, respectively, and ADMA transporters (CAT-1, CAT-2A and CAT-2B). Lipid peroxides (TBARS), glutathione, ATP/ADP and DDAH activity were quantified. An increase in serum AST and ALT was detected in MCD animals. A time-dependent decrease in serum and tissue ADMA and increase in mRNA expression of DDAH-1 and PRMT-1 as well as higher rates of mRNA expression of CAT-1 and lower rates of CAT-2A and CAT-2B were found after 8-week MCD diet. An increase in serum NOx and no changes in protein expression in DDAH-1 and CAT-1 and higher content in CAT-2 and PRMT-1 were found at 8 weeks. Hepatic DDAH activity decreased with a concomitant increase in oxidative stress, as demonstrated by high TBARS levels and low glutathione content. In conclusion, a decrease in serum and tissue ADMA levels in the MCD rats was found associated with a reduction in DDAH activity due to the marked oxidative stress observed. Changes in ADMA levels and its transporters are innovative factors in the onset and progression of hepatic alterations correlated with MCD diet-induced NASH.

Association of non-alcoholic fatty liver disease with impaired endothelial function by flow-mediated dilation: A meta-analysis

AIM

Endothelial dysfunction was observed in patients with non-alcoholic fatty liver disease. The aim of the present study was to evaluate the extent of endothelial function impairment in patients with non-alcoholic fatty liver disease.

METHODS

We systematically searched through the PubMed, Embase, China National Knowledge Infrastructure and Wanfang databases for studies dated up to January 2015. All observational studies that compared endothelial function between non-alcoholic fatty liver disease patients and healthy controls were included. Endothelial function was measured by brachial artery flow-mediated dilation and nitrate-induced dilatation techniques.

RESULTS

Eleven observational studies were identified. Meta-analysis indicated that non-alcoholic fatty liver disease patients were associated with a reduction in brachial artery flow-mediated dilation (weighted mean difference, -4.82%; 95% confidence interval [CI], -5.63 to -4.00) compared with the healthy controls. Subgroup analysis indicated that the patients with non-alcoholic steatohepatitis or a body mass index of more than 30 kg/m(2) appeared to have a greater reduction in their flow-mediated dilation. However, no significant differences were observed in the nitrate-induced dilation (weighted mean difference, -0.4%; 95% confidence interval, -2.19 to 1.39).

CONCLUSION

Non-alcoholic fatty liver disease is associated with a greater risk of endothelial dysfunction as indicated by the decreased brachial artery flow-mediated dilation. Assessment of endothelial function may be recommended to identify subclinical atherosclerosis and to create subgroups of non-alcoholic fatty liver disease patients who are at higher risk of future cardiovascular events.

Increased serum soluble lectin-like oxidized low-density lipoprotein receptor-1 levels in patients with biopsy-proven nonalcoholic fatty liver disease

AIM

To analyze the relationship between the serum lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) levels and clinical and histopathological features of biopsy-confirmed nonalcoholic fatty liver disease (NAFLD) patients.

METHODS

Fifty-three consecutive, biopsy-proven NAFLD patients (31 males and 22 females, mean age 42.5 ± 9.6 years) and 26 age- and gender-matched, healthy controls (14 males and 12 females, mean age 39 ± 10.7 years) were included. The patients with NAFLD were consecutive patients who had been admitted to the hepatology outpatient clinic within the last year and had been diagnosed with NAFLD as the result of liver biopsy. The healthy controls were individuals who attended the outpatient clinic for routine health control and had no known chronic illnesses. The histological evaluation was conducted according to the NAFLD activity scoring system recommended by The National Institute of Diabetes and Digestive and Kidney Diseases Nonalcoholic Steatohepatitis Clinical Research Network. The serum LOX-1 levels were measured using an ELISA kit (Life Science Inc. USCN. Wuhan, Catalog No. E1859Hu) in both patients and healthy controls. A receiver operating characteristic (ROC) curve analysis was used to identify the optimal cutoff value of LOX-1 and thereby distinguish between patients with nonalcoholic steatohepatitis (NASH) and healthy controls. A P-value < 0.05 was considered statistically significant.

RESULTS

NAFLD and healthy control groups were similar in terms of age and sex. NAFLD patients consisted of 8 patients with simple steatosis (15%), 27 with borderline NASH (51%) and 18 with definitive NASH (34%). Metabolic syndrome was found in 62.2% of the patients with NAFLD. The mean serum LOX-1 level in biopsy-proven NAFLD patients was 8.49 ± 6.43 ng/mL compared to 4.08 ± 4.32 ng/mL in healthy controls (P = 0.001). The LOX-1 levels were significantly different between controls, simple steatosis and NASH (borderline+definite) cases (4.08 ± 4.32 ng/mL, 6.1 ± 6.16 ng/mL, 8.92 ± 6.45 ng/mL, respectively, P = 0.004). When the cut-off value for the serum LOX-1 level was set at 5.35 ng/mL, and a ROC curve analysis was performed to distinguish between steatohepatitis patients and controls; the sensitivity and specificity of the serum LOX-1 level were 69.8% and 69.2%, respectively.

CONCLUSION

The serum LOX-1 levels were significantly higher in NAFLD patients than in healthy controls. Additionally, the serum LOX-1 levels could differentiate between steatohepatitis patients and healthy controls.

Causes of Thickening of Carotid Intima-Media Thickness in Patients With Alcoholic Liver Disease: A Prospective Observational Study

Several studies have reported the relationship between alcoholic liver disease (ALD) and carotid intima-media thickness (CIMT). Few studies, however, have investigated the causes of CIMT thickening in patients with ALD. The authors explored the causes of CIMT thickening in patients with ALD. The authors enrolled 152 patients who were stratified into groups: nonthickening CIMT with ALD (group A); thickening CIMT with ALD (group B); nonthickening CIMT without ALD (group C); and thickening CIMT without ALD (group D). The CIMT was significantly different between patients with and without ALD (χ 2= 3.875, P = 0.049). The patients in groups A, B, and C were significantly younger than group D (P = 0.001, 0.036, and 0.001, respectively). The body mass indexes (BMI) in groups A and B were significantly higher than in group C (P = 0.000 and 0.007, respectively). The blood glucose levels in groups B and D were significantly higher than in group C (P = 0.016 and 0.018, respectively). The blood uric acid levels in group B were significantly higher than in groups A, C, and D (P = 0.009, 0.000, and 0.003, respectively). The blood uric acid in group A was significantly higher than in group C (P = 0.002). The serum total cholesterol (TC) levels of patients in group B were significantly higher than in groups A and C (P = 0.027 and 0.000, respectively) and the serum TC level in group A was significantly higher than in group C (P = 0.048). The serum triglyceride (TG) levels in groups A and B were significantly higher than in group C (P = 0.027 and 0.000, respectively). The serum of very low-density lipoprotein (VLDL) levels in group B were significantly higher than in group C (P = 0.000). Although a comparison of the low-density lipoprotein (LDL) and high-density lipoprotein (HDL) serum levels among the 4 groups indicated no changes. The serum LDL levels in group B were significantly higher than in group A (P = 0.008). No significant differences were observed among the groups with respect to serum homocysteine, C-reactive protein (CRP), interleukin-6 (IL-6), malondialdehyde (MDA), superoxide dismutase (SOD), soluble OX40 ligand (sOX40L), or heat shock protein (HSP) 60 or 70. Alcoholic liver disease may result in CIMT thickening. Carotid intima-media thickness is associated with age and metabolic factors in patients with ALD. In addition, ALD might promote the premature occurrence of CIMT thickening. The thickening of carotid artery intima thickness, however, is not associated with cytokine profiles, oxidative balance, or immune responses in patients with ALD.

Oxidative stress: New insights on the association of non-alcoholic fatty liver disease and atherosclerosis

Non-alcoholic fatty liver disease (NAFLD) represents the most common and emerging chronic liver disease worldwide. It includes a wide spectrum of liver diseases ranging from simple fatty liver to non-alcoholic steatohepatitis (NASH), which may progress to fibrosis and more severe liver complications such as cirrhosis, hepatocellular carcinoma and liver mortality. NAFLD is strongly associated with obesity, insulin resistance, hypertension, and dyslipidaemia, and is now regarded as the liver manifestation of the metabolic syndrome. The increased mortality of patients with NAFLD is primarily a result of cardiovascular disease and, to a lesser extent, to liver related diseases. Increased oxidative stress has been reported in both patients with NAFLD and patient with cardiovascular risk factors. Thus, oxidative stress represents a shared pathophysiological disorder between the two conditions. Several therapeutic strategies targeting oxidative stress reduction in patients with NAFLD have been proposed, with conflicting results. In particular, vitamin E supplementation has been suggested for the treatment of non-diabetic, non-cirrhotic adults with active NASH, although this recommendation is based only on the results of a single randomized controlled trial. Other antioxidant treatments suggested are resveratrol, silybin, L-carnitine and pentoxiphylline. No trial so far, has evaluated the cardiovascular effects of antioxidant treatment in patients with NAFLD. New, large-scale studies including as end-point also the assessment of the atherosclerosis markers are needed.

Relation of nonalcoholic fatty liver disease and Framingham Risk Score to flow-mediated dilation in patients with cardiometabolic risk factors

Nonalcoholic fatty liver disease (NAFLD) has a high prevalence in the general population. Brachial artery flow-mediated dilation (FMD) is a surrogated marker of early atherosclerosis. Few data investigating the relation between FMD, NAFLD, and cardiovascular (CV) risk are available. We recruited 367 consecutive outpatients with cardiometabolic risk factors who underwent ultrasound scanning for liver steatosis and FMD. Mean age was 54.2 ± 12.2 years, and 37% were women. NAFLD was present in 281 patients (77%). Median FMD was 5.1%. FMD was significantly reduced in patients with NAFLD (p <0.001), diabetes (p = 0.001), history of coronary heart disease (p = 0.034), and metabolic syndrome (p = 0.050) and in those taking antihypertensive drugs (p = 0.022). Women disclosed greater FMD than males (p = 0.033). Moreover, FMD inversely correlated with age (Spearman rank correlation test [Rs], -0.171; p = 0.001), waist circumference (Rs, -0.127; p = 0.016), fasting blood glucose (Rs, -0.204; p <0.001), and gamma-glutamyl transpeptidase (Rs, -0.064; p = 0.234). At multivariate regression analysis, fasting blood glucose (β, -0.148; p = 0.008), age (β, -0.158; p = 0.005), and the presence of NAFLD (β, -0.132; p = 0.016) inversely correlated with FMD, whereas female gender predicted a better FMD (β, 0.125; p = 0.022). FMD and Framingham Risk Score (FRS) were inversely correlated (Rs, -0.183; p <0.001). After dividing patients into low (FRS <10; FMD, 5.5% [3.1% to 8.9%]), intermediate (FRS 10 to 20; FMD, 4.9% [2.7% to 7.5%]), and high (FRS >20; FMD, 3.3% [1.7% to 4.5%]) risk, FMD significantly decreased across risk classes of FRS (p = 0.003). At multivariate regression analysis, both FRS (β, -0.129; p = 0.016) and NAFLD (β, -0.218; p <0.001) were variables independently associated with FMD. In conclusion, the presence of NAFLD and FRS inversely correlated with FMD.

Nonalcoholic fatty liver disease and vascular function: cross-sectional analysis in the Framingham heart study

OBJECTIVE

Patients with nonalcoholic fatty liver disease (NAFLD) have an increased risk of cardiovascular disease; however, it is not known whether NAFLD contributes to cardiovascular disease independent of established risk factors. We examined the association between NAFLD and vascular function.

APPROACH AND RESULTS

We conducted a cross-sectional study of 2284 Framingham Heart Study participants without overt cardiovascular disease who had liver fat attenuation measured on computed tomography and who had measurements of vascular function and covariates. We evaluated the association between NAFLD and vascular function using multivariable partial correlations adjusting for age, sex, cohort, smoking, diabetes mellitus, hyperlipidemia, hypertension, body mass index, and visceral adipose tissue. The prevalence of NAFLD in our sample (mean age, 52±12 years; 51.4% women) was 15.3%. In age-, sex-, and cohort-adjusted analyses, greater liver fat was modestly associated with lower flow-mediated dilation (r=-0.05; P=0.02), lower peripheral arterial tonometry ratio (r=-0.20; P<0.0001), higher carotid-femoral pulse wave velocity (r=0.13; P<0.0001), and higher mean arterial pressure (r=0.11; P<0.0001). In multivariable-adjusted models, NAFLD remained associated with higher mean arterial pressure (r=0.06; P=0.005) and lower peripheral arterial tonometry ratio (r=-0.12; P<0.0001). The association between NAFLD and peripheral arterial tonometry ratio persisted after further adjustment for body mass index and visceral adipose tissue.

CONCLUSIONS

For multiple measures of vascular function, the relationship with NAFLD appeared largely determined by shared cardiometabolic risk factors. The persistent relationship with reduced peripheral arterial tonometry response beyond established risk factors suggests that NAFLD may contribute to microvascular dysfunction.

A concise review of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and the incidence of which is rising rapidly due to the increasing epidemic of obesity in both adults and children. The initial accumulation of fat followed by subsequent inflammation is central to the development of liver damage, and is critically influenced by host factors including age, gender, presence of diabetes, genetic polymorphisms and more recently by the gut microbiome. An increasing body of data suggest that NAFLD is also an independent risk factor of cardiovascular disease, which remains the commonest cause of mortality in such patients. This review focusses on the pathogenesis of NAFLD, and the evolution of new approaches to the management and treatment of NAFLD.

Is there a rationale for treatment of chronic liver disease with antithrombotic therapy?

Recent advances in the understanding of the coagulopathy in chronic liver disease have provided a strong support for anticoagulation as a new therapeutic paradigm for patients with cirrhosis. Laboratory studies indicate that the net effect of changes in hemostasis in many patients with chronic liver disease is a hypercoagulable status. In turn, clinical thrombosis is increasingly recognized as a complication of liver disease. When occurring within the liver, thrombosis may even progress the disease course. Exciting preliminary data regarding the potential of low-molecular-weight heparin to slow down the progression of liver disease indicate that this class of drugs may improve outcome without a major increase in bleeding risk. However, this new era for antithrombotic therapy in chronic liver disease is still hindered by a persistent false notion that patients with cirrhosis are "auto-anticoagulated" by their underlying liver disease. In addition, there is insufficient clinical evidence on safety and efficacy of anticoagulant therapy in cirrhosis and the studies conducted so far are limited by small sample sizes, uncontrolled treatment arms, or by their retrospective nature. Finally, a lack of knowledge on how or when to monitor antithrombotic treatment to optimize the risk-benefit ratio has restricted a widespread application of anticoagulant treatment in clinical management algorithms. Nonetheless, by systematically covering possibilities and pitfalls, this review highlights the potential of antithrombotic therapy to improve the quality of life and the clinical outcome of patients with chronic liver disease.