Nonalcoholic Fatty Liver Disease Is Associated With Ventricular Arrhythmias in Patients With Type 2 Diabetes Referred for Clinically Indicated 24-Hour Holter Monitoring

Extrahepatic Manifestations of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) represents a global public health burden. NAFLD, while strongly associated with the metabolic syndrome, can occur independently from existing metabolic diseases. In addition to liver-related disease burden and mortality, significant extrahepatic disease outcomes coexist with NAFLD, including cardiovascular diseases, chronic kidney disease, and type 2 diabetes. Management of these comorbidities contributes to the overall public health burden of NAFLD. These extrahepatic manifestations require healthcare interventions that are vigilant in monitoring for progression of liver disease while simultaneously managing overall morbidity and mortality from other organ systems.

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

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

Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus: A Bidirectional Relationship

Worldwide, the leading cause of chronic liver disease is represented by nonalcoholic fatty liver disease (NAFLD) which has now become a global epidemic of the 21st century, affecting 1 in 4 adults, and which appears to be associated with the steadily increasing rates of metabolic syndrome and its components (obesity, type 2 diabetes mellitus (T2DM), and dyslipidemia). NAFLD has been reported to be associated with extrahepatic manifestations such as cardiovascular disease, T2DM, chronic kidney disease, extrahepatic malignancies (e.g., colorectal cancer), endocrine diseases (e.g., hypothyroidism, polycystic ovarian syndrome, psoriasis, and osteoporosis), obstructive sleep apnea, and iron overload. The prevalence of NAFLD is very high, affecting 25-30% of the world population and encloses two steps: (1) nonalcoholic fatty liver (NAFL), which includes steatosis only, and (2) nonalcoholic steatohepatitis (NASH) defined by the presence of steatosis and inflammation with hepatocyte ballooning, with or without fibrosis which can progress to liver fibrosis, hepatocellular carcinoma, and liver transplantation. Current data define a more complex relationship between NAFLD and T2DM than was previously believed, underlining a bidirectional and mutual association between the two entities. This review aims to summarize the current literature regarding the incidence of T2DM among patients with NAFLD and also the prevalence of NAFLD in T2DM patients, highlighting the recent key studies. Clinicians should screen, diagnose, and treat T2DM in patients with NAFLD in order to avoid short- and long-term complications.

Cardiac abnormalities in patients with nonalcoholic fatty liver disease : Insights from auxiliary examinations

Nonalcoholic fatty liver disease (NAFLD) is one of the most common forms of chronic liver disease in developed countries and is associated with type 2 diabetes mellitus, obesity, hypertension, dyslipidemia, and metabolic syndrome. It is defined as steatosis in over 5% of hepatocytes. The disease spectrum of NAFLD ranges from simple fatty liver to nonalcoholic steatohepatitis, liver fibrosis, even hepatic cirrhosis. The disease affects various extra-hepatic systems such as the cardiovascular system and urinary system. Heart-related disease is identified as the leading cause of mortality in NAFLD patients rather than liver-related disease. In this review, we summarize the cardiac abnormalities (structural, functional, arrhythmic cardiac complications etc.) seen in NAFLD patients with the assistance of auxiliary examinations, such as electrocardiography, echocardiography, computed tomography, magnetic resonance imaging etc. In addition, the epidemiology of NAFLD and how NAFLD affects the myocardium are also discussed.

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.

Cardiovascular Risk in Non-Alcoholic Fatty Liver Disease: Mechanisms and Therapeutic Implications

New evidence suggests that non-alcoholic fatty liver disease (NAFLD) has a strong multifaceted relationship with diabetes and metabolic syndrome, and is associated with increased risk of cardiovascular events, regardless of traditional risk factors, such as hypertension, diabetes, dyslipidemia, and obesity. Given the pandemic-level rise of NAFLD—in parallel with the increasing prevalence of obesity and other components of the metabolic syndrome—and its association with poor cardiovascular outcomes, the question of how to manage NAFLD properly, in order to reduce the burden of associated incident cardiovascular events, is both timely and highly relevant. This review aims to summarize the current knowledge of the association between NAFLD and cardiovascular disease, and also to discuss possible clinical strategies for cardiovascular risk assessment, as well as the spectrum of available therapeutic strategies for the prevention and treatment of NAFLD and its downstream events.

Predictors, burden and impact of cardiac arrhythmias among patients hospitalized with end-stage liver disease

BACKGROUND

Cirrhotic cardiomyopathy, hyperammonemia, and hepatorenal syndrome predispose to cardiac arrhythmias in End-stage liver disease (ESLD).

OBJECTIVES

Among ESLD hospitalizations, we evaluate the distribution and predictors of arrhythmias and their impact on hospitalization outcomes.

METHODS

We selected ESLD records from the Nationwide Inpatient Sample (2007-2014), identified concomitant arrhythmias (tachyarrhythmias and bradyarrhythmias), and their demographic and comorbid characteristics, and estimated the effect of arrhythmia on outcomes (SAS 9.4).

RESULTS

Of 57,119 ESLD hospitalizations, 6,615 had arrhythmias with higher odds with increasing age, males, jaundice, hepatorenal syndrome, alcohol use, and cardiopulmonary disorders. The most common arrhythmias were atrial fibrillation, cardiac arrest/asystole, and ventricular tachycardia. After propensity-matching (arrhythmia: no-arrhythmia, 6,609:6,609), arrhythmias were associated with 200% higher mortality, 1.7-days longer stay, $32,880 higher cost, and higher rates of shock, respiratory and kidney failures.

CONCLUSIONS

Due to worse outcomes with arrhythmias, there is a need for better screening and follow-up of ESLD patients for dysrhythmias.

Predictive value of gamma-glutamyltransferase for ventricular arrhythmias and cardiovascular mortality in implantable cardioverter-defibrillator patients

Background

Gamma-glutamyltransferase (GGT) is a new predictor of cardiovascular diseases. In this study, we aimed to determine its association with ventricular arrhythmias (VAs) in implantable cardioverter-defibrillator (ICD) patients.

Methods

One hundred and forty patients implanted with ICD or cardiac resynchronization therapy defibrillator with home monitoring were studied retrospectively. The primary endpoint was appropriate ICD treatment of VAs, secondary endpoint was cardiac death.

Results

During a mean follow-up period of 44 ± 17 months, 78 patients (55.7%) experienced VAs, 50 patients (35.7%) were treated with appropriate ICD shocks and 16 patients (11.4%) died due to cardiovascular diseases. GGT was positively correlated with high sensitivity C reactive protein (r = 0.482, P < 0.001), left ventricular end-diastolic dimension (r = 0.175, P = 0.039), New York Heart Association class (r = 0.199, P = 0.018), fasting blood glucose (r = 0.233, P = 0.006) and negatively with left ventricular ejection fraction (r = − 0.181, P = 0.032) and high-density lipoprotein (r = − 0.313, P < 0.001). Based on receiver operating characteristics curve, the cut-off value of GGT = 56 U/L was identified to predict VAs. In Kaplan-Meier survival analysis, GGT ≥56 U/L was associated with increased VAs (P<0.001), ICD shock events (P = 0.006) and cardiovascular mortality (P = 0.003). In multivariate COX regression models, GGT ≥56 U/L was an independent risk factor for VAs (HR 2.253, 95%CI:1.383–3.671, P = 0.001), ICD shocks (HR 2.256, 95%CI:1.219–4.176, P = 0.010) and cardiac death (HR 3.555, 95%CI:1.215–10.404, P = 0.021).

Conclusions

In this ICD population, GGT ≥56 U/L was independently associated with VAs and cardiac death.

Cardio-Metabolic Disorders in Non-Alcoholic Fatty Liver Disease

With the progressive epidemics of obesity, non-alcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease in adults and children. The increasing prevalence and incidence of NAFLD with advanced fibrosis is concerning because patients appear to experience higher non-liver-related morbidity and mortality than the general population. Recent clinical evidence suggests that NAFLD is directly associated with an increased risk of cardio-metabolic disorders. This mini review describes briefly the current understanding of the pathogenesis of NAFLD, summarizing the link between NAFLD and cardio-metabolic complications, focusing mainly upon ischemic stroke, type 2 diabetes mellitus (DM), hypertension, chronic kidney disease (CKD) and cardiac arrhythmias. In addition, it describes briefly the current understanding of the pathogenesis of NAFLD.

The association of non-alcoholic fatty liver disease and atrial fibrillation: a review

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent and causes an enormous burden to human health and health-care systems all over the world. A great proportion of this burden results from increased risk of cardiovascular diseases. Atrial fibrillation (AF) is the most common chronic heart arrhythmia globally and it increases the risk of embolic stroke and heart failure. Recent studies have explored the association between NAFLD and AF with somewhat conflicting results. However, ultrasound-verified prospective studies concur that NAFLD is associated with the incidence of AF. According to epidemiological evidence, the greater the prevalence of NALFD in a population, the stronger the association with AF incidence and prevalence. Specifically, diabetic individuals with NAFLD are at the greatest risk of AF. Additionally, the risk of AF may concentrate most in individuals with advanced NAFLD, particularly those with liver fibrosis. The possible mechanistic factors between NAFLD and AF, particularly obesity and systemic inflammation, are diverse and form a complex interplaying network. However, further studies are needed to elucidate whether NAFLD has a causative role in the development of AF. The purpose of this article is to review and discuss the epidemiologic evidence and possible mechanistic links between these two conditions. KEY MESSAGES Although epidemiologic studies have provided conflicting results on the association of NAFLD and AF, prospective studies with ultrasound-verified NAFLD concur that NAFLD is associated with about 2-fold greater incidence of AF among general population and about 6-fold greater incidence among subjects with type 2 diabetes. The risk of AF among individuals with NAFLD is increased by other cardiovascular risk factors, especially type 2 diabetes and advanced age. The possible mechanistic links between NALFD and AF are diverse, with obesity and systemic inflammation having a significant role, but further studies are needed until NAFLD can be established as a causal factor in the incidence of AF.

Risk of cardiomyopathy and cardiac arrhythmias in patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a common, progressive liver disease that affects up to one-quarter of the adult population worldwide. The clinical and economic burden of NAFLD is mainly due to liver-related morbidity and mortality (nonalcoholic steatohepatitis, cirrhosis or hepatocellular carcinoma) and an increased risk of developing fatal and nonfatal cardiovascular disease, chronic kidney disease and certain types of extrahepatic cancers (for example, colorectal cancer and breast cancer). Additionally, there is now accumulating evidence that NAFLD adversely affects not only the coronary arteries (promoting accelerated coronary atherosclerosis) but also all other anatomical structures of the heart, conferring an increased risk of cardiomyopathy (mainly left ventricular diastolic dysfunction and hypertrophy, leading to the development of congestive heart failure), cardiac valvular calcification (mainly aortic-valve sclerosis), cardiac arrhythmias (mainly atrial fibrillation) and some cardiac conduction defects. This Review focuses on the association between NAFLD and non-ischaemia-related cardiac disease, discusses the putative pathophysiological mechanisms and briefly summarizes current treatment options for NAFLD that might also beneficially affect cardiac disease.

Fatty Liver and the Forensic Pathologist

Fatty liver is a common finding in clinical practice and at autopsy. It is most commonly seen associated with alcohol abuse and in non-alcoholic fatty liver disease (NAFLD). It may also be seen in many other conditions in both adults and children. It is now recognized that NAFLD, like alcoholic liver disease, may lead to end stage liver disease. Nonalcoholic fatty liver disease is associated with increased mortality from other disorders, particularly cardiovascular diseases. Fatty liver may be seen in many conditions that concern autopsy pathologists, including drug toxicity, anorexia, hepatic ischemia, and heatstroke. In infants, steatosis is common in sudden unexpected deaths. Fatty liver has been associated with sudden death and this review examines the pathology and role of fatty liver in sudden death. Acad Forensic Pathol. 2018 8(2): 296-310.

Nonalcoholic fatty liver disease and chronic vascular complications of diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD) and diabetes mellitus are common diseases that often coexist and might act synergistically to increase the risk of hepatic and extra-hepatic clinical outcomes. NAFLD affects up to 70-80% of patients with type 2 diabetes mellitus and up to 30-40% of adults with type 1 diabetes mellitus. The coexistence of NAFLD and diabetes mellitus increases the risk of developing not only the more severe forms of NAFLD but also chronic vascular complications of diabetes mellitus. Indeed, substantial evidence links NAFLD with an increased risk of developing cardiovascular disease and other cardiac and arrhythmic complications in patients with type 1 diabetes mellitus or type 2 diabetes mellitus. NAFLD is also associated with an increased risk of developing microvascular diabetic complications, especially chronic kidney disease. This Review focuses on the strong association between NAFLD and the risk of chronic vascular complications in patients with type 1 diabetes mellitus or type 2 diabetes mellitus, thereby promoting an increased awareness of the extra-hepatic implications of this increasingly prevalent and burdensome liver disease. We also discuss the putative underlying mechanisms by which NAFLD contributes to vascular diseases, as well as the emerging role of changes in the gut microbiota (dysbiosis) in the pathogenesis of NAFLD and associated vascular diseases.

Non-Alcoholic Fatty Liver Disease: The Emerging Burden in Cardiometabolic and Renal Diseases

As the number of individuals with non-alcoholic fatty liver disease (NAFLD) has increased, the influence of NAFLD on other metabolic diseases has been highlighted. Accumulating epidemiologic evidence indicates that NAFLD not only affects the liver but also increases the risk of extra-hepatic diseases such as type 2 diabetes mellitus, metabolic syndrome, dyslipidemia, hypertension, cardiovascular or cerebrovascular diseases, and chronic kidney disease. Non-alcoholic steatohepatitis, an advanced type of NAFLD, can aggravate these inter-organ relationships and lead to poorer outcomes. NAFLD induces insulin resistance and exacerbates systemic chronic inflammation and oxidative stress, which leads to organ dysfunction in extra-hepatic tissues. Although more research is needed to identify the pathophysiological mechanisms and causal relationship between NAFLD and cardiometabolic and renal diseases, screening for heart, brain, and kidney diseases, risk assessment for diabetes, and a multidisciplinary approach for managing these patients should be highly encouraged.

Nonalcoholic fatty liver disease is associated with an increased risk of heart block in hospitalized patients with type 2 diabetes mellitus

Recent studies suggested that nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiac tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus. The aim of this study was to examine whether an association also exists between NAFLD and heart block. We have retrospectively evaluated a hospital-based cohort of 751 patients with type 2 diabetes discharged from our Division of Diabetes and Endocrinology during years 2007–2014. Standard electrocardiograms were performed on all patients. Diagnosis of NAFLD was based on ultrasonography, whereas the severity of advanced hepatic fibrosis was based on the fibrosis (FIB)-4 score and other non-invasive fibrosis markers. Overall, 524 (69.8%) patients had NAFLD and 202 (26.9%) had heart block (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block) on electrocardiograms. Patients with NAFLD had a remarkably higher prevalence of any persistent heart block than those without NAFLD (31.3% vs. 16.7%, p<0.001); this prevalence was particularly increased among those with higher FIB-4 score. NAFLD was associated with a threefold increased risk of prevalent heart block (adjusted-odds ratio 3.04, 95% CI 1.81–5.10), independently of age, sex, hypertension, prior ischemic heart disease, hemoglobin A1c, microvascular complication status, use of medications and other potentially confounding factors. In conclusion, this is the largest cross-sectional study to show that NAFLD and its severity are independently associated with an increased risk of prevalent heart block in hospitalized patients with type 2 diabetes.

Prevalence of nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus: A meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is emerging as a public health issue worldwide and is highly prevalent in patients with type 2 diabetes mellitus (T2DM). However, there was a great disparity across studies in the estimated prevalence of NAFLD in T2DM patients. This meta-analysis, therefore, aimed to estimate the pooled prevalence of NAFLD in T2DM patients.

METHODS

Electronic databases of PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure, and Wanfang were searched using MeSH terms to identify relevant studies. Eligibility assessment and data extraction were conducted independently by 2 investigators and a meta-analysis was performed to synthesize the data. Heterogeneity was evaluated using the Cochran Q test and quantified using the I statistic. Publication bias was assessed using both the Begg and Egger tests. Subgroup analyses were performed to identify the possible sources of heterogeneity.

RESULTS

Twenty-four studies involving 35,599 T2DM patients were included in this meta-analysis, of which 20,264 were identified with NAFLD. A high degree of heterogeneity (I = 99.0%, P < .001) was observed among the eligible studies, with the reported prevalence ranging from 29.6% to 87.1%. The pooled prevalence of NAFLD in T2DM patients, by a random-effects model, was 59.67% (95% confidence interval: 54.31-64.92%). Sensitivity was low and both the Begg test and Egger test showed low possibility of publication bias. Subgroup analyses indicated that the prevalence of NAFLD in T2DM patients differed by gender, obesity, hypertension, dyslipidemia, coronary heart disease, and chronic kidney disease.

CONCLUSIONS

The high pooled prevalence of NAFLD in T2DM patients found in this study significantly underscores the need for early assessment of NAFLD and the importance of strengthening the management of NAFLD in T2DM patients.

Nonalcoholic Fatty Liver Disease (NAFLD) and Risk of Cardiac Arrhythmias: A New Aspect of the Liver-heart Axis

Nonalcoholic fatty liver disease (NAFLD) is a pathologic condition frequently observed in clinical practice. To date, the prevalence of NAFLD is approximately 25-30% among adults of the general population in Western countries but increases to approximately 70-75% among patients with type 2 diabetes mellitus. In the last decade, accumulating evidence has clearly demonstrated that patients with NAFLD have not only an increased liver-related morbidity and mortality but also an increased risk of fatal and non-fatal cardiovascular events. In particular, several studies have documented the existence of an independent association among NAFLD and cardiac changes in structure and function in both non-diabetic and diabetic patients. In addition, mounting evidence also suggests that there is a strong relationship between NAFLD and cardiac arrhythmias, such as atrial fibrillation, QTc prolongation and ventricular arrhythmias. This is of clinical interest, as it could explain, at least in part, the increased risk of death for cardiovascular disease in patients with NAFLD. Therefore, seeing that cardiovascular disease complications are the leading cause of disability and death in NAFLD patients, the recent European clinical practice guidelines advised to check the cardiovascular system in all patients with NAFLD. This clinical mini review will briefly describe the increasing body of evidence regarding the association between NAFLD and cardiac arrhythmias, and discuss the potential biological mechanisms underlying this association.

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

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

AISF position paper on nonalcoholic fatty liver disease (NAFLD): Updates and future directions

This review summarizes our current understanding of nonalcoholic fatty liver disease (NAFLD), a multi-factorial systemic disease resulting from a complex interaction between a specific genetic background and multiple environmental/metabolic "hits". The role of gut microbiota, lipotoxicity, inflammation and their molecular pathways is reviewed in-depth. We also discuss the epidemiology and natural history of NAFLD by pinpointing the remarkably high prevalence of NAFLD worldwide and its inherent systemic complications: hepatic (steatohepatitis, advanced fibrosis and cirrhosis), cardio-metabolic (cardiovascular disease, cardiomyopathy, arrhythmias and type 2 diabetes) and neoplastic (primary liver cancers and extra-hepatic cancers). Moreover, we critically report on the diagnostic role of non-invasive biomarkers, imaging techniques and liver biopsy, which remains the reference standard for diagnosing the disease, but cannot be proposed to all patients with suspected NAFLD. Finally, the management of NAFLD is also reviewed, by highlighting the lifestyle changes and the pharmacological options, with a focus on the innovative drugs. We conclude that the results of ongoing studies are eagerly expected to lead to introduce into the clinical arena new diagnostic and prognostic biomarkers, prevention and surveillance strategies as well as to new drugs for a tailored approach to the management of NAFLD in the individual patient.

Non-Alcoholic Fatty Liver Disease Association with Cardiac Arrhythmias

Non-alcoholic fatty liver disease (NAFLD) has become a public health burden all over the world. A significant percentage of the patients with NAFLD have a co-existing metabolic syndrome that is a risk factor for cardiovascular disease. Clinical as well as epidemiological research shows that NAFLD is not simply related to liver-related morbidity and mortality but is also associated with an elevated risk of coronary heart disease (CHD), irregularities of cardiac function as well as cardiac structure, valvular heart disease, and arrhythmias. Animal studies suggest that NAFLD by itself exacerbates systemic/hepatic insulin resistance, leads to atherogenic dyslipidemia and generates a number of pro-inflammatory, pro-coagulant and profibrogenic mediators which play an essential role in the pathophysiology of cardiac abnormalities including arrhythmias. Hence, it is suggested that the patients with NAFLD may derive benefit from intensive monitoring and treatment methods to reduce the risk of CHD along with other cardiac/arrhythmic complications. The intent of this clinical review is to sum up the quickly increasing body of evidence that provides support for a robust relationship between NAFLD and cardiac arrhythmias and to present the putative biological mechanisms underlying this correlation.

[The informative value of non-invasive liver fibrosis markers in patients with nonalcoholic fatty liver disease]

AIM

To estimate the diagnostic and informative value of clinical and laboratory parameters in the development and progression of liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) to enhance efficiency of their treatment.

SUBJECTS AND METHODS

An open-label case-control study included 77 patients with NAFLD. Clinical and laboratory examinations were done. To search for additional noninvasive fibrosis markers, the investigators studied the serum concentrations of insulin, leptin, adiponectin, matrix metalloproteinase-9 (MMP-9) and its inhibitors, such as tissue inhibitor of matrix metalloproteinases 1 (TIMP-1) and TIMP-2. All the patients underwent elastometry to assess the degree of liver fibrosis with the Metavir scale with the use of a Fibroscan machine.

RESULTS

The serum levels of low-density lipoproteins, glucose, MMP-9, and leptin proved to be most informative in assessing the progression of the initial stages (1-2) of fibrosis, as were the increased liver size detected by physical examination, systolic blood pressure, carbohydrate metabolic disorders, alanine/aspartate aminotransferase levels, waist-to-hip ratio, TIMP-1, and TIMP-2 in evaluating the progression of Stage II fibrosis 2 to Stage 3.

CONCLUSION

The clinical and laboratory parameters can serve as reliable noninvasive markers that reflect the progression of fibrotic changes in liver tissue.

Nonalcoholic Fatty Liver Disease and Associated Metabolic Risks of Hypertension in Type 2 Diabetes: A Cross-Sectional Community-Based Study

The mechanisms facilitating hypertension in diabetes still remain to be elucidated. Nonalcoholic fatty liver disease (NAFLD), which is a higher risk factor for insulin resistance, shares many predisposing factors with diabetes. However, little work has been performed on the pathogenesis of hypertension in type 2 diabetes (T2DM) with NAFLD. The aim of this study is to investigate the prevalence of hypertension in different glycemic statuses and to analyze relationships between NAFLD, metabolic risks, and hypertension within a large community-based population after informed written consent. A total of 9473 subjects aged over 45 years, including 1648 patients with T2DM, were enrolled in this cross-sectional study. Clinical and biochemical parameters of all participants were determined. The results suggested that the patients with prediabetes or T2DM were with higher risks to have hypertension. T2DM with NAFLD had significantly higher levels of blood pressure, triglyceride, uric acid, and HOMA-IR than those without NAFLD. Data analyses suggested that hypertriglyceridemia [OR = 1.773 (1.396, 2.251)], NAFLD [OR = 2.344 (1.736, 3.165)], hyperuricemia [OR = 1.474 (1.079, 2.012)], and insulin resistance [OR = 1.948 (1.540, 2.465)] were associated with the higher prevalence of hypertension independent of other metabolic risk factors in type 2 diabetes. Further studies are needed to focus on these associations.

Gamma-glutamyl transferase and cardiovascular disease

Gamma-glutamyl transferase (GGT) is an enzyme located on the external surface of cellular membranes. GGT contributes in maintaining the physiological concentrations of cytoplasmic glutathione and cellular defense against oxidative stress via cleavage of extracellular glutathione and increased availability of amino acids for its intracellular synthesis. Increased GGT activity is a marker of antioxidant inadequacy and increased oxidative stress. Ample evidence suggests that elevated GGT activity is associated with increased risk of cardiovascular disease (CVD) such as coronary heart disease (CHD), stroke, arterial hypertension, heart failure, cardiac arrhythmias and all-cause and CVD-related mortality. The evidence is weaker for an association between elevated GGT activity and acute ischemic events and myocardial infarction. The risk for CVD or CVD-related mortality mediated by GGT may be explained by the close correlation of GGT with conventional CVD risk factors and various comorbidities, particularly non-alcoholic fatty liver disease, alcohol consumption, oxidative stress, metabolic syndrome, insulin resistance and systemic inflammation. The finding of GGT activity in atherosclerotic plaques and correlation of intra-plaque GGT activity with histological indexes of plaque instability may suggest a participation of GGT in the pathophysiology of CVD, particularly atherosclerosis. However, whether GGT has a direct role in the pathophysiology of CVD or it is an epiphenomenon of coexisting CVD risk factors or comorbidities remains unknown and Hill's criteria of causality relationship between GGT and CVD are not fulfilled. The exploration whether GGT provides prognostic information on top of the information provided by known cardiovascular risk factors regarding the CVD or CVD-related outcome and exploration of molecular mechanisms of GGT involvement in the pathophysiology of CVD and eventual use of interventions to reduce circulating GGT activity remain a duty of future studies.

Gamma-glutamyltransferase-friend or foe within?

Gamma-glutamyltransferase (GGT) is a liver enzyme, which is located on the plasma membranes of most cells and organ tissues, but more commonly in hepatocytes, and is routinely used in clinical practice to help indicate liver injury and as a marker of excessive alcohol consumption. Among the liver enzymes, important advances have especially been made in understanding the physiological functions of GGT. The primary role of GGT is the extracellular catabolism of glutathione, the major thiol antioxidant in mammalian cells, which plays a relevant role in protecting cells against oxidants produced during normal metabolism; GGT, therefore, plays an important role in cellular defence. Beyond its physiological functions, circulating serum GGT has been linked to a remarkable array of chronic conditions and diseases, which include nonalcoholic fatty liver disease, vascular and nonvascular diseases and mortality outcomes. This review summarizes the available epidemiological and genetic evidence for the associations between GGT and these adverse outcomes, the postulated biologic mechanisms underlying these associations, outlines areas of outstanding uncertainty and the implications for clinical practice.

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

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

Nonalcoholic fatty liver disease is independently associated with an increased incidence of cardiovascular disease in adult patients with type 1 diabetes

BACKGROUND

Recent studies suggested that nonalcoholic fatty liver disease (NAFLD) is associated with an increased prevalence of cardiovascular disease (CVD) in type 1 diabetes. We assessed whether NAFLD also predicts the risk of incident CVD events in type 1 diabetic adults.

METHODS

We studied a retrospective cohort of 286 type 1 diabetic outpatients (mean age 43±14years; median duration of diabetes 17 [10-30] years) without secondary causes of chronic liver diseases, who were followed for a mean period of 5.3years for the occurrence of incident CVD events (a combined endpoint inclusive of nonfatal ischemic heart disease, nonfatal ischemic stroke or coronary/peripheral artery revascularizations). NAFLD was diagnosed by ultrasonography.

RESULTS

Overall, 150 patients (52.4%) had NAFLD at baseline. During a mean follow-up of 5.3±2.1years, 28 patients developed incident CVD events. Patients with NAFLD had a higher incidence of CVD events than those without NAFLD (17.3% vs. 1.5%, p<0.001). NAFLD was associated with an increased risk of CVD events (hazard ratio [HR] 8.16, 95% confidence interval [CI] 1.9-35.1, p<0.005). Adjustments for age, sex, body mass index, smoking, diabetes duration, hemoglobin A1c, dyslipidemia, hypertension, chronic kidney disease, prior ischemic heart disease and serum gamma-glutamyltransferase levels did not appreciably attenuate the association between NAFLD and incident CVD (adjusted-HR 6.73, 95% CI 1.2-38.1, p=0.031).

CONCLUSIONS

This is the first observational study to demonstrate that NAFLD is associated with an increased risk of incident CVD events in type 1 diabetic adults, independently of established CVD risk factors and diabetes-related variables.