Evaluation of early atherosclerosis markers 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.

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.

Iron overload accelerated lipid metabolism disorder and liver injury in rats with non-alcoholic fatty liver disease

Background/aims

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. Iron overload has been implicated in chronic non-communicable liver diseases, but its relationship with NAFLD remains unclear. This study aimed to investigate the underlying roles of iron overload in the development of NAFLD.

Methods

Male Sprague Dawley rats were fed with a high-fat diet (HFD) and/or iron for 8, 12, and 20 weeks. Some rats fed with HFD plus iron also received intraperitoneal injection of deferoxamine (DFO) for 8 weeks. Liver steatosis, lipid metabolism and injury were evaluated.

Results

A NAFLD model, including typical liver steatosis, was established by feeding rats with a HFD, while iron overload alone is not enough to induce severe NAFL. Compared with rats fed a HFD, excess iron further increased lipid accumulation, serum levels of lipids, enzymes of liver function, and expression levels of CD36 and FAS in rat liver. In addition, iron overload decreased the activities of antioxidative enzymes in liver compared with HFD rats. The levels of CPT1 and the ratios of p-ACC/ACC were also decreased by iron overload. DFO effectively reversed the abnormal lipid metabolism and liver damage induced by a high-fat, high-iron diet.

Conclusion

A HFD plus iron overload might synergistically aggravate lipid metabolism disorders, liver injury, and oxidative damage, compared with a HFD alone. DFO might help to alleviate lipid metabolism dysfunction and improve the pathogenesis of NAFLD.

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.

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.

Atherosclerosis and Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a common disease defined by excess fat deposition in the liver. The course of NAFLD is not fully understood, however, some pathogenic mechanisms have been identified. Accumulation of fat in liver cells is associated with insulin resistance, central obesity, triglyceride accumulation in the liver and hepatic fatty acid metabolism dysregulation that cause steatosis. The other process leads to hepatocyte inflammation and necrosis, which leads to severe hepatic disease; non-alcoholic steatohepatitis. Many clinical studies have underlined the link between NAFLD and atherosclerosis. NAFLD may alter the balance lipid-glucose metabolism as well as increase the risk of hypertension and systemic inflammation. This results in a greater risk of vascular events. The present review considers the link between NAFLD and atherosclerosis.

Association between non-alcoholic fatty liver disease and subclinical atherosclerosis in Western and Asian cohorts: an updated meta-analysis

Background

Non-alcoholic fatty liver disease (NAFLD) is a well-established risk factor for cardiovascular disease, with ethnic and regional differences noted. With the recent surge of research within this field, we re-examine the evidence associating NAFLD with subclinical atherosclerosis, and investigate potential regional differences.

Methods

This is a systematic review and meta-analysis. PubMed and EMBASE were systematically searched for publications from January 1967 to July 2020 using standardised criteria. Original, observational studies investigating the association between NAFLD and either carotid intima-media thickness (CIMT) and/or coronary artery calcification (CAC) were included. Key outcomes included differences in mean CIMT, the presence of increased CIMT, the presence of CAC and the development/progression of CAC. Pooled ORs and pooled standard differences in means were calculated using random-effects models. Between-study heterogeneity was quantified using the Q statistic and I². Subgroup analyses stratified by region of study (Asian vs Western) were also conducted.

Results

64 studies involving a total of 172 385 participants (67 404 with NAFLD) were included. 44 studies assessed the effect of NAFLD on CIMT, with the presence of NAFLD associated with increased CIMT (OR 2.00, 95% CI 1.56 to 2.56). 22 studies assessed the effects of NAFLD on CAC score, with the presence of NAFLD associated with the presence of any coronary calcification (OR 1.21, 95% CI 1.12 to 1.32), and the development/progression of CAC (OR 1.26, 95% CI 1.04 to 1.52). When stratified by region, these associations remained consistent across both Asian and Western populations (p>0.05). The majority (n=39) of studies were classified as ‘high quality’, with the remaining 25 of ‘moderate quality’.

Conclusions

There is a significant positive association between various measures of subclinical atherosclerosis and NAFLD, seen across both Western and Asian populations. These results re-emphasise the importance of early risk evaluation and prophylactic intervention measures to preclude progression to clinical cardiovascular disease in patients with NAFLD.

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.

Gut microbiota modulation as a promising therapy with metformin in rats with non-alcoholic steatohepatitis: Role of LPS/TLR4 and autophagy pathways

Gut microbiota is a crucial factor in pathogenesis of non-alcoholic steatohepatitis (NASH). Therefore, targeting the gut-liver axis might be a novel therapeutic approach to treat NASH. This study aimed to investigate the therapeutic effects of a probiotic (Lactobacillus reuteri) and metronidazole (MTZ) (an antibiotic against Bacteroidetes) either alone or in combination with metformin (MTF) in experimentally-induced NASH. NASH was induced by feeding rats high fat diet (HFD) for 12 weeks. MTF (150 mg/kg/day) or L. reuteri (2x10⁹ colony forming unit/day) were given orally for 8 weeks; meanwhile, MTZ (15 mg/kg/day, p.o.) was administered for 1 week. Treatment with L. reuteri and MTZ in combination with MTF showed additional benefit compared to MTF alone concerning lipid profile, liver function, oxidative stress, inflammatory and autophagic markers. Furthermore, combined regimen succeeded to modulate acetate: propionate: butyrate ratios as well as Firmicutes and Bacteroidetes fecal contents with improvement of insulin resistance (IR). Yet, the administration of MTF alone failed to normalize Bacteriodetes and acetate contents which could be the reason for its moderate effect. In conclusion, gut microbiota modulation may be an attractive therapeutic avenue against NASH. More attention should be paid to deciphering the crosstalk mechanisms linking gut microbiota to non-alcoholic fatty liver disease (NAFLD) to identify new therapeutic targets for this disease.

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.

Non-alcoholic fatty liver disease: Relationship with cardiovascular risk markers and clinical endpoints

Non-alcoholic fatty liver disease (NAFLD) is a common diagnosis and is increasing in prevalence worldwide. NAFLD is usually asymptomatic at presentation; progression of the disease is unpredictable, leading to the development of a variety of techniques for screening, diagnosis and risk stratification. Clinical methods in current use include serum biomarker panels, hepatic ultrasound, magnetic resonance imaging, and liver biopsy. NAFLD is strongly associated with the metabolic syndrome, and the most common cause of death for people with the condition is cardiovascular disease. Whether NAFLD is an independent cardiovascular risk factor needs exploration. NAFLD has been associated with surrogate markers of cardiovascular disease such as carotid intima-media thickness, the presence of carotid plaque, brachial artery vasodilatory responsiveness and CT coronary artery calcification score. There is no effective medical treatment for NAFLD and evidence is lacking regarding the efficacy of interventions in mitigating cardiovascular risk. Health care professionals managing patients with NAFLD should tackle the issue with early identification of risk factors and aggressive modification. Current management strategies therefore comprise lifestyle change, with close attention to known cardiovascular risk factors.

Non-alcoholic fatty liver disease (NAFLD) and 10-year risk of cardiovascular diseases

BACKGROUND AND AIMS

The association between cardiovascular diseases (CVD) and non-alcoholic fatty liver disease (NAFLD) was confirmed by a large body of evidence. This study was conducted to determine the association between NAFLD and 10-year CVD risk.

METHODS

This study utilized the data of 2804 subjects aged 40-74 years from a cohort study of northern Iran. Two CVD risk assessment tools, American College of Cardiology/American Heart Association and Framingham general cardiovascular risk profile for use in primary care, were utilized to determine the 10-year CVD risk in patients with NAFLD and the individuals without this condition. The mean risks were compared between these two groups.

RESULTS

Using ACC/AHA approach, the mean risk in male participants suffering NAFLD was 14.2%, while in men without NAFLD was 11.7% (P-value < 0.0001). Using Framingham approach, the mean risks were 16.0 and 12.7% in men with and without NAFLD, respectively (P-value < 0.0001). Using ACC/AHA approach, the mean risks in female participants with and without NAFLD were 6.7 and 4.6%, respectively (P-value < 0.0001). Applying Framingham approach, the mean risk was 8.2% in women with NAFLD and 5.4% in women without NAFLD (P-value < 0.0001).

CONCLUSION

The individuals with NAFLD had a higher risk of 10-year CVD events than individuals without NAFLD, according to both ACC/AHA tool and primary care version of Framingham tool. A large proportion of NAFLD patients fulfill the criteria of statin therapy recommendation, suggesting that statin therapy could reduce 10-year CVD risk in NAFLD patients.

Nonalcoholic fatty liver disease - A multisystem disease?

Non-alcoholic fatty liver disease (NAFLD) is one of the most common comorbidities associated with overweight and metabolic syndrome (MetS). Importantly, NAFLD is one of its most dangerous complications because it can lead to severe liver pathologies, including fibrosis, cirrhosis and hepatic cellular carcinoma. Given the increasing worldwide prevalence of obesity, NAFLD has become the most common cause of chronic liver disease and therefore is a major global health problem. Currently, NAFLD is predominantly regarded as a hepatic manifestation of MetS. However, accumulating evidence indicates that the effects of NAFLD extend beyond the liver and are negatively associated with a range of chronic diseases, most notably cardiovascular disease (CVD), diabetes mellitus type 2 (T2DM) and chronic kidney disease (CKD). It is becoming increasingly clear that these diseases are the result of the same underlying pathophysiological processes associated with MetS, such as insulin resistance, chronic systemic inflammation and dyslipidemia. As a result, they have been shown to be independent reciprocal risk factors. In addition, recent data have shown that NAFLD actively contributes to aggravation of the pathophysiology of CVD, T2DM, and CKD, as well as several other pathologies. Thus, NAFLD is a direct cause of many chronic diseases associated with MetS, and better detection and treatment of fatty liver disease is therefore urgently needed. As non-invasive screening methods for liver disease become increasingly available, detection and treatment of NAFLD in patients with MetS should therefore be considered by both (sub-) specialists and primary care physicians.

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.

Research advances in the relationship between nonalcoholic fatty liver disease and atherosclerosis

Nonalcoholic fatty liver disease (NAFLD) is a metabolic stress-induced liver disease that is closely related not only to genetic susceptibility but also to insulin resistance and highly linked with metabolic syndrome. In recent years, the prevalence of NAFLD has increased rapidly, paralleling the epidemic of type 2 diabetes mellitus and obesity leading to cardiovascular disease. It has been demonstrated that NAFLD is highly associated with atherosclerosis. With recently gained knowledge, it appears that NAFLD may induce insulin resistance, dyslipidemia, oxidative stress, inflammation, and fluctuation of adipokines associated with atherosclerosis. In this review, we aimed to summarize recent discoveries related to both NAFLD and atherosclerosis, and to identify possible mechanisms linking them.

Nonalcoholic fatty liver disease and carotid artery atherosclerosis in children and adults: a meta-analysis

Observational studies suggest that nonalcoholic fatty liver disease (NAFLD) is associated with increased carotid intimal medial thickness (C-IMT) and carotid plaques in both children and adults. We carried out a meta-analysis to evaluate the relationship between NAFLD and carotid atherosclerosis measured as C-IMT and carotid plaque prevalence. Medline (Ovid), PubMed, Web of Science, and CINAHL databases were searched from 1946 to September 2014, complemented with a manual review of references of the published articles for studies that compared C-IMT or carotid plaque prevalence in adults and children. Results were pooled using both fixed and random effects models. Of the studies identified, 20 were suitable for testing the effect of NAFLD on C-IMT in adults, 13 for testing the effect of NAFLD on carotid plaque prevalence in adults, and five for testing the effect of NAFLD on C-IMT in the pediatric population. The pooled data from 20 studies (19,274 adult participants: NAFLD=8652, controls=10,622) showed significantly increased C-IMT in patients with NAFLD, compared with controls without NAFLD, according to both fixed [standardized mean difference (SMD)=0.251, 95% confidence interval (CI): 0.220-0.282, P<0.001] and random effects models (SMD=0.944, 95% CI: 0.728-1.160, P<0.001). NAFLD was also found to be associated with a higher carotid artery plaque prevalence when compared with controls, according to both fixed (OR=1.273, 95% CI=1.162-1.394, P<0.001) and random effects models (OR=1.769, 95% CI: 1.213-2.581, P=0.003), on pooling of 13 studies (14,445 adult participants: NAFLD=5399 and controls=9046). Analysis of pooled data from five studies in the pediatric population (1121 pediatric participants: NAFLD=312 and controls=809) also found NAFLD to be associated with significantly increased C-IMT according to fixed (SMD=0.995, 95% CI: 0.840-1.150, P<0.001) and random effects models (1.083, 95% CI: 0.457-1.709, P=0.001). NAFLD is associated with increased C-IMT in both children and adults, and with increased carotid plaque prevalence in adults. Individuals identified with carotid disease should be evaluated for NAFLD and vice versa.

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.

Characterization of a novel endothelial biosensor assay reveals increased cumulative serum inflammatory potential in stabilized coronary artery disease patients

Background

Vascular disease is promoted by systemic inflammation that can arise from sites distal to the affected vessels. We sought to characterize the net inflammatory potential of serum from patients with coronary artery disease (CAD) using cultured endothelial cells as a cumulative biosensor.

Methods and results

Serum samples from CAD patients (N = 45) and healthy control subjects (N = 48) were incubated with primary human coronary artery endothelial cells at a 1:10 dilution for 4 h, followed by isolation of the cellular RNA. Alteration of inflammation-responsive elements (adhesion molecules and cytokines) was assessed by gene expression. Specific indicators included intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and interleukin-8 (IL-8). Additionally, the cytokine levels in serum samples from all subjects were quantified. Serum from CAD subjects induced greater endothelial ICAM-1, VCAM-1, and IL-8 expression compared to healthy control serum (p < 0.001 for each analysis). The three indicators of inflammatory potential (ICAM-1, VCAM-1, and IL-8 mRNA) trended independently of each other and also of serum inflammatory biomarkers. IL-8 expression correlated negatively with serum HDL levels but positively correlated with VLDL, plasminogen activator inhibitor-1 and C-reactive protein. Interestingly, serum levels of cytokines in CAD patients were not statistically different from healthy control subjects. A year of follow-up in a sub-group of CAD subjects revealed relatively stable measures.

Conclusions

As yet unidentified circulating factors in the serum of CAD patients appear to activate endothelial cells, leading to upregulation of adhesion molecules and chemokines. This cumulative assay performed well in terms of discriminating patients with CAD compared to healthy subjects, with greater range and specificity than specific inflammatory markers.

Association between liver fibrosis and coronary heart disease risk in patients with nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is being increasingly recognized as the most common cause of chronic liver disease worldwide. It has been shown that NAFLD in adults is associated with increased risk of coronary heart disease (CHD). Because of the limitations of liver biopsy, noninvasive scoring indexes such as the NAFLD fibrosis score (NFS) were developed. The Framingham risk score (FRS) provides an estimate of CHD risk. In our study we aimed to investigate whether the severity of liver fibrosis estimated with the NFS is associated with a higher risk of CHD among individuals with ultrasonography-diagnosed NAFLD.

STUDY

A total of 155 patients and controls (81 patients with NAFLD and 74 controls) with ages ranging from 18 to 70 years were enrolled in this cross-sectional prospective study. Demographic, anthropometric, clinical, and laboratory data were obtained from each individual. The NAFLD patients were divided into subgroups on the basis of the severity of fatty liver. The FRS and NFS were adopted to predict the risk of CHD and the severity of hepatic fibrosis.

RESULTS

In our study, we found that the FRS was higher in NAFLD patients than in controls (P<0.05). According to the FRS category, NFSs were higher in the intermediate/high probability CHD risk group in NAFLD (P<0.05). In multiple models, only age, sex, cholesterol, and HDL were independently associated with intermediate/high CHD risk (P<0.05). We also found a positive correlation between the NFS and the FRS (r=0.373, P<0.001). The optimum NFS cutoff point for identifying intermediate/high CHD risk in NAFLD patients was -2.1284, with a sensitivity and specificity of 95.20 and 48.30%, respectively. The predictive performance of the NFS in the determination of intermediate/high CHD risk in NAFLD patients was found to be 72% based on the area under the curve value.

CONCLUSION

The FRS is associated with the NFS in NAFLD. The assessment of liver fibrosis may be useful for the risk stratification of CHD in the absence of liver biopsy in clinical practice.

Inflammatory bowel disease, liver diseases and endothelial function: is there a linkage?

Atherosclerosis is a systemic inflammatory disease able to deeply worsen the outcome of patients because of its serious clinical consequences. The complex inflammatory background underlining such a disease makes atherosclerosis linked to several systemic inflammatory conditions able to impair endothelial function and morphology. Inflammatory bowel diseases are a group of gastrointestinal diseases including Crohn's disease and ulcerative colitis, that is, syndromes characterized by changes in mucosal immunity and gastrointestinal physiology, which could negatively influence the vascular endothelial function and structure. Hepatitis (i.e. inflammatory diseases of the liver mainly due to viral infections) and nonalcoholic fatty liver disease could be aligned to inflammatory bowel disease in such an induction of atherosclerosis disease.Many studies tried to point out the relationship between bowel and liver inflammatory diseases and early vascular changes, considered the first step for atherosclerosis development.The aim of such a narrative review is to explain the relationship between inflammatory bowel disease, hepatitis and nonalcoholic fatty liver disease and their role in increasing cardiovascular risk profile due to early impairment in vascular function and morphology.

Nonalcoholic fatty liver disease and vascular disease: State-of-the-art

Nonalcoholic fatty liver disease (NAFLD), the most common of chronic liver disease in Western Country, is closely related to insulin resistance and oxidative stress and includes a wide spectrum of liver diseases ranging from steatosis alone, usually a benign and non-progressive condition, to nonalcoholic steatohepatitis (NASH), which may progress to liver fibrosis and cirrhosis. NAFLD is considered the hepatic manifestation of the metabolic syndrome with which shares several characteristics, however recent data suggest that NAFLD is linked to increased cardiovascular risk independently of the broad spectrum of risk factors of metabolic syndrome. Accumulating evidence suggests that the clinical burden of NAFLD is not restricted to liver-related morbidity and mortality, with the majority of deaths in NAFLD patients related to cardiovascular disease and cancer and not to the progression of liver disease. Retrospective and prospective studies provide evidence of a strong association between NAFLD and subclinical manifestation of atherosclerosis (increased intima-media thickness, endothelial dysfunction, arterial stiffness, impaired left ventricular function and coronary calcification). A general agreement emerging from these studies indicates that patients with NASH are at higher risk of cardiovascular diseases than those with simple steatosis, emphasizing the role of chronic inflammation in the pathogenesis of atherosclerosis of these patients. It is very likely that the different mechanisms involved in the pathogenesis of atherosclerosis in patients with NAFLD have a different relevance in the patients according to individual genetic background. In conclusion, in the presence of NAFLD patients should undergo a complete cardiovascular evaluation to prevent future atherosclerotic complications. Specific life-style modification and aggressive pharmaceutical modification will not only reduce the progression of liver disease, but also reduce morbidity for cardiovascular disease improving overall prognosis and survival.

Metabolic syndrome and nonalcoholic fatty liver disease. The role of endothelial progenitor cells

BACKGROUND

Endothelial dysfunction has been previously described in metabolic syndrome patients. The levels of circulating endothelial progenitor cells (EPCs) inversely correlates with the incidence of cardiovascular disease. The aim of this study was to investigate the association between NAFLD, metabolic syndrome and EPC levels.

MATERIAL AND METHODS

A cross-sectional pilot study was performed at a university hospital in Mexico. Two groups of patients without previously known chronic diseases were studied and classified according to the presence of NAFLD. Anthropometric, dietary, and biochemical variables, and circulating EPC number were measured and compared between the groups.

RESULTS

Forty subjects were included and classified into two groups: patients with NAFLD (n = 20) and a control group (n = 20). The overall prevalence of insulin resistance and metabolic syndrome was 25% and 17.5%, respectively. EPC levels were found to be higher in the NAFLD group (p < 0.05) as in the patients with insulin resistance (p < 0.01) and metabolic syndrome (p < 0.01). These levels showed correlation with the severity of steatosis.

CONCLUSIONS

Patients with NAFLD have increased levels of EPC, such levels are associated with the severity of NAFLD. These findings may suggest that these cells may play a role in the early natural history of NAFLD. EPC might be increased in an attempt to repair the endothelial damage resulting from metabolic alterations accompanying NAFLD. Further studies are needed to establish the dynamics of these cells in NAFLD.