Hepatic steatosis is associated with an increased risk of carotid atherosclerosis

Alleviation of high-fat diet-induced atherosclerosis and glucose intolerance by a novel GLP-1 fusion protein in ApoE(-/-) mice

We have previously constructed an engineered anti-diabetic fusion protein using glucagon-like peptide-1 and the globular domain of adiponectin. Herein, we evaluated the therapeutic effects of this fusion protein (GAD) on high-fat diet (HFD)-fed ApoE(-/-) mice. The lipid-lowering effect of GAD was determined in C57BL/6 mice using a lipid tolerance test. The effects of GAD on HFD-induced glucose intolerance, atherosclerosis, and hepatic steatosis were evaluated in HFD-fed ApoE(-/-) mice using glucose tolerance test, histological examinations and real-time quantitative PCR. The anti-inflammation activity of GAD was assessed in vitro on macrophages. GAD improved lipid metabolism in C57BL/6 mice. GAD treatment alleviated glucose intolerance, reduced blood lipid level, and attenuated atherosclerotic lesion in HFD-fed ApoE(-/-) mice, which was associated with a repressed macrophage infiltration in the vessel wall. GAD treatment also blocked hepatic macrophage infiltration and prevented hepatic inflammation. GAD suppressed lipopolysaccharide-triggered inflammation responses on macrophages, which can be abolished by H89, an inhibitor of protein kinase A. These findings demonstrate that GAD is able to generate a variety of metabolic benefits in HFD-fed ApoE(-/-) mice and indicate that this engineered fusion protein is a promising lead structure for anti-atherosclerosis drug discovery.

Epidemiology of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis in the United States and the Rest of the World

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease with increasing prevalence, which can progress to cirrhosis and liver failure. Because of the obesity epidemic and increasing prevalence of metabolic syndrome, NAFLD and its progressive form, nonalcoholic steatohepatitis, are seen more commonly in different parts of the world. This article reviews the worldwide epidemiology of NAFLD and nonalcoholic steatohepatitis. The PubMed database was used to identify studies related to epidemiology of NAFLD in the adult population. It is estimated that the epidemic of obesity will continue to fuel the burden of NAFLD and its long-term complications.

Metabolic Manifestations and Complications Associated With Chronic Hepatitis C Virus Infection

Chronic hepatitis C virus (HCV) infection is associated with many extrahepatic manifestations that contribute to morbidity and mortality. It is especially important to be aware of metabolic manifestations and serious complications that affect other organs and cancer risks. Chronic HCV infection itself contributes to de novo development of insulin resistance and hepatic steatosis, both of which increase the risk of cardiovascular diseases. Through these metabolic pathways (as well as through other hypothesized mechanisms that involve lipid metabolism, systemic inflammatory signals, and endothelial dysfunction), chronic HCV infection also contributes to significant systemic cardiovascular morbidity and mortality. While chronic HCV infection contributes to incident development of metabolic complications, the presence of concurrent metabolic diseases also contributes to disease progression, such as higher risks of hepatocellular carcinoma and progression to advanced fibrosis, among patients with chronic HCV infection. The implications of these observations are particularly important given the rising prevalence of obesity and metabolic syndrome in the United States and worldwide. Furthermore, concurrent nonalcoholic fatty liver disease, either as a result of underlying metabolic syndrome or as a direct result of HCV-induced fatty liver disease, further complicates the management of chronic HCV-infected patients. Greater awareness is needed toward the systemic manifestations of chronic HCV infection, with focused attention on the associated metabolic manifestations and complications. Successful treatment and cure of chronic HCV infection with the currently available, highly effective antiviral therapies will significantly improve long-term outcomes among these patients. It is also important to recognize and address the associated metabolic manifestations and complications to reduce cardiovascular-related morbidity and mortality.

Extrahepatic Manifestations of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide with an increased prevalence of metabolic, macro- and microvascular complications. The primary causes of mortality in NAFLD are cardiovascular disease (CVD), malignancy and liver disease. NAFLD is a multisystem disease that affects a variety of extra-hepatic organ systems. The main focus of this review is to summarize the reported extra-hepatic associations, which include CVD, chronic kidney disease, obstructive sleep apnea, osteoporosis, psoriasis, colorectal cancer, iron overload and various endocrinopathies (e.g. type 2 diabetes mellitus, thyroid dysfunction, and polycystic ovarian syndrome). Due to the systemic manifestations of NAFLD patients require a multidisciplinary assessment and may benefit from more rigorous surveillance and early treatment interventions to decrease mortality related to malignancy or cardiometabolic diseases.

Correlation between nonalcoholic fatty liver and cardiovascular disease in elderly hemodialysis patients

PURPOSE

The number of elderly patients with end-stage kidney disease is on the rise. Nonalcoholic fatty liver disease (NAFLD) is characterized by parenchymal fat accumulation in patients without information about alcohol abuse. The aim of our study was to determine correlation between NAFLD and cardiovascular diseases in elderly hemodialysis patients.

METHODS

The examination was organized as observational and cross-sectional study in elderly patients on hemodialysis. An abdominal ultrasound examination was made in order to define NAFLD. Intima-media thickness of the carotid arteries was quantified by Doppler ultrasound. Biochemical parameters, gender, anthropometric characteristics, duration, adequacy of hemodialysis, blood pressure, smoking and cardiovascular disease were determined. Respondents were divided into a group with NAFLD (37/72 patients, 51 %) and group without NAFLD (35/72 patients, 49 %).

RESULTS

Patients with NAFLD have significantly more cardiovascular disease (p = 0.017) as well as significantly higher values of intima-media thickness of the carotid arteries (p = 0.03) in correlation with patients without NAFLD. Patients without NAFLD have a statistically lower triglyceride (p = 0.04), aspartate aminotransferase (p = 0.006), alanine aminotransferase (p = 0.013) and gamma-glutamyl transpeptidase (p = 0.029) compared to patients with NAFLD. Patients with cardiovascular disease have a higher risk of NAFLD; likewise, patients with NAFLD have a three times higher chance for developing cardiovascular diseases (OR 3.01).

CONCLUSION

Elderly patients on hemodialysis with cardiovascular disease have a higher risk of NAFLD; likewise, patients with NAFLD have a three times higher chance for developing cardiovascular diseases.

The synergistic impact of nonalcoholic fatty liver disease and metabolic syndrome on subclinical atherosclerosis

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is a well-known contributor for the development of cardiovascular disease (CVD). We examined the influence of NAFLD and metabolic syndrome (MetS) on markers of subclinical atherosclerosis, including carotid intima-media thickness (CIMT), brachial-ankle pulse wave velocity (baPWV) and ankle-brachial pressure index (ABI), after adjusting for cardiometabolic risk factors.

DESIGN

A cross-sectional study.

PATIENTS AND MEASUREMENTS

The association between NAFLD, MetS and markers of subclinical atherosclerosis was assessed in 955 participants without CVD using multiple logistic regression analysis after adjusting for multiple cardiometabolic risk variables.

RESULTS

After adjusting for age and sex, CIMT and baPWV were found to be significantly correlated with multiple cardiometabolic risk variables, whereas ABI was only associated with obesity parameters. The prevalence of NAFLD differed significantly according to the presence of subclinical atherosclerosis as defined by both CIMT and baPWV (P = 0·004 and P = 0·007, respectively). After adjusting for potential confounding factors, NAFLD or MetS was not associated with subclinical atherosclerosis as defined by CIMT and baPWV. However, individuals with both NAFLD and MetS had a significantly higher risk of subclinical atherosclerosis as defined by CIMT (OR = 2·06, 95% CI = 1·13-3·74) or baPWV (OR = 2·64, 95% CI = 1·46-4·76) compared to normal subjects, even after adjusting for potential confounders.

CONCLUSIONS

The results show that NAFLD and MetS have a synergistic impact on the subclinical atherosclerosis, which suggests that individuals with both NAFLD and MetS should be strongly advised to engage in CVD prevention strategies.

Subclinical atherosclerosis is associated with Epicardial Fat Thickness and hepatic steatosis in the general population

BACKGROUND AND AIMS

Abdominal obesity and hepatic steatosis are ectopic fat depots associated with Metabolic Syndrome (MetS). Epicardial Fat Thickness (EFT) is a newly discovered one, increasing with obesity, insulin resistance and MetS. Therefore we studied whether different ectopic fat markers, and EFT in particular, are associated with MetS and markers of subclinical cardiovascular disease.

METHODS AND RESULTS

868 subjects from the PLIC Study were included, EFT, aortic calcifications, carotid Intima-Media Thickness (c-IMT) and echocardiographic parameters were determined by ultrasound; extra-cardiac atherosclerotic lesions were defined in presence of plaques at both carotid and aortic levels. Hepatic steatosis degrees were defined according to a scoring system. Abdominal adiposity was determined using Dual X-ray Absorbimetry (DEXA). Independently from age, women showed higher EFT versus men (4.5 (0.20-9.00) mm vs 4.00 (0.10-8.00) mm, p = 0.013); EFT was thicker in post-menopausal women (independently from hormone-replacement therapy). EFT, liver steatosis and abdominal adiposity increased with MetS (p < 0.001). EFT was the only ectopic fat marker associated with cardiac dysfunction (OR = 1.340 [1.088-1.651 95% C.I., p = 0.006); liver steatosis and EFT were associated with extra-cardiac plaques (OR = 2.529 [1.328-4.819] 95% C.I., p < 0.001 and OR = 1.195 [1.008-1.299] 95% C.I., p = 0.042; respectively). On top of cardiovascular risk factors, only EFT improved the discrimination of subjects with cardiac dysfunction and atherosclerotic plaques.

CONCLUSIONS

EFT is associated with left ventricular dysfunction and subclinical atherosclerosis. Our data suggest that EFT may represent an additional tool for the stratification of cardiovascular risk.

Liver fat content is negatively associated with atherosclerotic carotid plaque in type 2 diabetic patients

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is independently associated with atherosclerosis in nondiabetic individuals. In type 2 diabetic patients, the link between fatty liver and atherosclerosis is less clear. Here, we assessed whether liver fat content evaluated using (1)H-magnetic resonance spectroscopy ((1)H-MRS) was independently associated with prevalent carotid plaque as a marker of atherosclerosis in type 2 diabetic patients.

METHODS

One hundred and forty-four prospectively enrolled patients with type 2 diabetes underwent liver fat content measurement using (1)H-MRS and carotid plaque assessment using ultrasound. Multiple logistic regressions were used to identify factors associated with carotid plaque.

RESULTS

Mean ± SD liver fat content was 9.86±8.12%. Carotid plaque prevalence was 52.1% (75/144). Patients without plaque were younger (P=0.006) and had a smaller visceral fat area (P=0.015), lower reported prevalence of previous cardiovascular events or current statin therapy (P=0.002), and higher liver fat content than those with plaque (P=0.009). By multivariable logistic regression, increased liver fat content independently predicted the absence of carotid plaque [odds ratios (ORs), 0.94; 95% confidence intervals (CIs), 0.89-0.99; P=0.017].

CONCLUSIONS

Liver fat content measured by (1)H-MRS is higher in type 2 diabetic patients without carotid plaque compared to those with plaque. This study suggests that increased liver fat content could be associated with a relative protection against carotid atherosclerosis in patients with type 2 diabetes mellitus.

Prevalence trends in lifestyle-related risk factors

BACKGROUND

The regional prevalence of risk factors can vary over time. The Study of Health in Pomerania (SHIP) addresses prevalence trends for common risk factors in a region in northeast Germany.

METHODS

A longitudinal study was carried out from 1997 to 2001 (SHIP-0, with 4308 subjects), and a second, independent random sample of the population in the same region was studied from 2008 to 2012 (SHIP-Trend, with 4420 subjects). All data were standardized with post-stratification weighting derived from the adult population of the state of Mecklenburg-West Pomerania.

RESULTS

SHIP reveals a marked decline of mean alcohol consumption in the adult population, from 5.57 g/day (95% confidence interval, 5.51-5.63) to 3.12 g/day (95% CI 3.09-3.15). The percentage of active smokers among men declined from 38.6% (95% CI 36.0-41.2) to 34.3% (95% CI 32.1-36.6). Simultaneously, however, there was a rightward shift of the BMI distribution, with a marked increase in the prevalence of obesity, from 24.7% to 32.0%. There was a corresponding increase in the prevalence of diabetes, from 9.1% to 13.8%. Compared to eleven years ago, the amount of exercise taken during free time has risen among the elderly, but fallen among young women.

CONCLUSION

Tobacco and alcohol consumption have declined over the past decade, although this study may have overestimated these trends through a combination of selection bias and reporting bias. Meanwhile, the northeast German population now has a worse metabolic risk profile, as indicated by the increased prevalence of obesity and diabetes. Society as a whole must take measures to combat this trend.

[Techniques for quantification of liver fat in risk stratification of diabetics]

CLINICAL/METHODICAL ISSUE

Fatty liver disease plays an important role in the development of type 2 diabetes. Accurate techniques for detection and quantification of liver fat are essential for clinical diagnostics.

STANDARD RADIOLOGICAL METHODS

Chemical shift-encoded magnetic resonance imaging (MRI) is a simple approach to quantify liver fat content.

METHODICAL INNOVATIONS

Liver fat quantification using chemical shift-encoded MRI is influenced by several bias factors, such as T2* decay, T1 recovery and the multispectral complexity of fat.

PERFORMANCE

The confounder corrected proton density fat fraction is a simple approach to quantify liver fat with comparable results independent of the software and hardware used.

ACHIEVEMENTS

The proton density fat fraction is an accurate biomarker for assessment of liver fat.

PRACTICAL RECOMMENDATIONS

An accurate and reproducible quantification of liver fat using chemical shift-encoded MRI requires a calculation of the proton density fat fraction.

Extrahepatic manifestations in chronic hepatitis C virus carriers

Patients with chronic hepatitis C virus (HCV) infection frequently present with extrahepatic manifestations covering a large spectrum, involving different organ systems leading to the concept of systemic HCV infection. These manifestations include autoimmune phenomena and frank autoimmune and/or rheumatic diseases and may dominate the course of chronic HCV infection. Chronic HCV infection causes liver inflammation affecting the development of hepatic diseases. HCV is also a lymphotropic virus that triggers B cells and promotes favorable conditions for B lymphocyte proliferation, including mixed cryoglobulinemia (MC) and MC vasculitis, which is the most prominent extrahepatic manifestation of chronic HCV infection. HCV may also promote a low-grade chronic systemic inflammation that may affect the development of some extrahepatic manifestations, particularly cardiovascular and cerebral vascular diseases. Recognition of extrahepatic symptoms of HCV infection could facilitate early diagnosis and treatment. The development of direct-acting antiviral agents (DDAs) has revolutionized HCV treatment. DDAs, as well as new B-cell-depleting or B-cell-modulating monoclonal antibodies, will expand the panorama of treatment options for HCV-related extrahepatic manifestations including cryoglobulinemic vasculitis. In this context, a proactive, integrated approach to HCV therapy should maximize the benefits of HCV therapy, even when liver disease is mild.

Impact of renal impairment on cardiovascular disease mortality after liver transplantation for nonalcoholic steatohepatitis cirrhosis

BACKGROUND & AIMS

Non-alcoholic steatohepatitis (NASH) is an independent risk factor for cardiovascular disease (CVD) morbidity after liver transplantation, but its impact on CVD mortality is unknown. We sought to assess the impact of NASH on CVD mortality after liver transplantation and to predict which NASH recipients are at highest risk of a CVD-related death following a liver transplant.

METHODS

Using the Organ Procurement and Transplantation Network database, we examined associations between NASH and post-liver transplant CVD mortality, defined as primary cause of death from thromboembolism, arrhythmia, heart failure, myocardial infarction or stroke. A physician panel reviewed cause of death.

RESULTS

Of 48 360 liver transplants (2/2002-12/2011), 5057 (10.5%) were performed for NASH cirrhosis. NASH recipients were more likely to be older, female, obese, diabetic and have history of renal failure or prior CVD vs. non-NASH (P < 0.001 for all). Although there was no difference in overall all-cause mortality (log-rank P = 0.96), both early (30-day) and long-term CVD-specific mortality was increased among NASH recipients (Odds ratio = 1.30, 95% Confidence interval (CI): 1.02-1.66; Hazard ratio = 1.42, 95% CI: 1.07-1.41 respectively). These associations were no longer significant after adjustment for pre-transplant diabetes, renal impairment or CVD. A risk score comprising age ≥55, male sex, diabetes and renal impairment was developed for prediction of post-liver transplant CVD mortality (c-statistic 0.60).

CONCLUSION

NASH recipients have an increased risk of CVD mortality after liver transplantation explained by a high prevalence of comorbid cardiometabolic risk factors that in aggregate identify those at highest risk of post-transplant CVD mortality.

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.

Association of nonalcoholic fatty liver disease with subclinical myocardial remodeling and dysfunction: A population-based study

Nonalcoholic fatty liver disease (NAFLD) and heart failure (HF) are obesity-related conditions with high cardiovascular mortality. Whether NAFLD is independently associated with subclinical myocardial remodeling or dysfunction among the general population is unknown. We performed a cross-sectional analysis of 2,713 participants from the multicenter, community-based Coronary Artery Risk Development in Young Adults (CARDIA) study who underwent concurrent computed tomography (CT) quantification of liver fat and comprehensive echocardiography with myocardial strain measured by speckle tracking during the Year-25 examination (age, 43-55 years; 58.8% female and 48.0% black). NAFLD was defined as liver attenuation ≤40 Hounsfield units after excluding other causes of liver fat. Subclinical left ventricular (LV) systolic dysfunction was defined using values of absolute peak global longitudinal strain (GLS). Diastolic dysfunction was defined using Doppler and tissue Doppler imaging markers. Prevalence of NAFLD was 10.0%. Participants with NAFLD had lower early diastolic relaxation (e') velocity (10.8 ± 2.6 vs. 11.9 ± 2.8 cm/s), higher LV filling pressure (E/e' ratio: 7.7 ± 2.6 vs. 7.0 ± 2.3), and worse absolute GLS (14.2 ± 2.4% vs. 15.2 ± 2.4%) than non-NAFLD (P < 0.0001 for all). When adjusted for HF risk factors or body mass index, NAFLD remained associated with subclinical myocardial remodeling and dysfunction (P < 0.01). The association of NAFLD with e' velocity (β = -0.36 [standard error = 0.15] cm/s; P = 0.02), E/e' ratio (β = 0.35 [0.16]; P = 0.03), and GLS (β = -0.42 [0.18]%; P = 0.02) was attenuated after controlling for visceral adipose tissue. Effect modification by race and sex was not observed.

CONCLUSIONS

NAFLD is independently associated with subclinical myocardial remodeling and dysfunction and provides further insight into a possible link between NAFLD and HF.

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 age are strong indicators for atherosclerosis in morbid obesity

OBJECTIVE

Whether nonalcoholic fatty liver disease (NAFLD) can predict atherosclerosis in obese patients remains unclear. The aim of our study was to investigate the usefulness of NAFLD and other cardiometabolic parameters in predicting subclinical atherosclerosis in obese patients.

DESIGN, PATIENTS AND MEASUREMENTS

We studied 314 consecutive obese subjects (223 women; mean age, 45·04 ± 9·34 years; body mass index 44·3 ± 5 kg/m(2) ) and 47 healthy lean individuals. Hepatic steatosis and atherosclerosis [carotid intima-media thickness (cIMT) >0·8 mm and/or presence of plaques] were evaluated ultrasonographically. Liver biopsies were obtained in 51 patients.

RESULTS

In obese patients, mean c-IMT was greater in those with NAFLD (P < 0·001). Hepatic steatosis and age were independent predictors of atherosclerosis: the NAFLD-associated OR for atherosclerosis was 5·96 (95%CI, 1·60-22·25; P = 0·008) in men and 8·26 (95%CI, 4·02-16·99; P < 0·001) in women, and the age-associated OR for atherosclerosis was 1·14 (95%CI, 1·07-1·22; P < 0·001) in men and 1·12 (95%CI, 1·08-1·17; P < 0·001) in women. The sensitivity, specificity and positive and negative predictive values of steatosis for atherosclerosis were 78·70%, 70·50%, 74·00% and 75·60% (AUC = 0·840) in men ≥43·5 years and 86·90%, 52·50%, 68·80% and 76·80% (AUC = 0·761) in women ≥47·5 years, respectively. Agreement between ultrasound-diagnosed steatosis and histology was good (ICC = 0·79). Combined NAFLD and age was the strongest predictor of atherosclerosis in obesity.

CONCLUSIONS

Nonalcoholic fatty liver disease and age may be independent risk factors for carotid atherosclerosis in obese individuals. Obese men and women with steatosis aged over 43·5 and 47·5 years, respectively, should be screened for carotid atherosclerosis. However, further evidence is necessary before suggesting an intervention based on current findings.

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.

Insulin resistance and its consequences in chronic hepatitis C

Chronic hepatitis C (CHC) is generally a slowly progressive disease, but some factors associated with rapid progression have been identified. Hepatitis C virus (HCV) may contribute to a broad spectrum of metabolic disturbances - namely, steatosis, insulin resistance (IR), increased prevalence of impaired glucose tolerance, type 2 diabetes mellitus (T2DM), lipid metabolism abnormalities and atherosclerosis. HCV can directly or indirectly cause both IR and steatosis, but it is still not resolved whether this viral impact bears the same prognostic value as the metabolic counterparts. As the population exposed to HCV ages, the morbidity due to this disease is increasing. The rising epidemic of obesity contributes to higher prevalence of IR and T2DM. Our understanding of the mutual association between both disease states continues to grow, but is still far from complete. This review briefly discusses the most probable mechanisms involved in IR development in the course of CHC. Molecular mechanisms for the direct and indirect influence of HCV on intracellular insulin signaling are described. Subsequently, the consequences of IR/T2DM for disease progression and management are summarized.

Comorbidities and Metabolic Derangement of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common cause of chronic liver disease worldwide and is becoming a major public health problem. NAFLD has been recognized as a hepatic manifestation of metabolic syndrome linked with insulin resistance. Growing evidence supports that NAFLD is associated with systemic diseases such as cardiovascular disease (CVD), chronic kidney disease (CKD), type 2 diabetes, obesity, and metabolic syndrome. The majority of deaths in patients with NAFLD come from cardiovascular disease. These findings are strongly attributed to nonalcoholic steatohepatitis (NASH) rather than simple steatosis. NAFLD should be considered not only a liver specific disease but also an early mediator of systemic disease. The underlying mechanisms and pathogenesis of NAFLD with regard to other medical disorders are not yet fully understood. Further investigation is needed for future therapeutic strategies for NAFLD. This review focuses on the relationship between NAFLD and various comorbid diseases and metabolic derangement.

Nonalcoholic Fatty liver disease and risk of diabetes and cardiovascular disease: what is important for primary care physicians?

Nonalcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver condition in Western World and across the globe. NAFLD prevalence is estimated to be around one-third of the total population. There are no published data that project the future prevalence of NAFLD, but with an increase in epidemic of diabetes and obesity, it is possible to suggest an increase in a number of individuals with NAFLD. NAFLD is associated with insulin resistance and occurs with an increase in cluster of features of metabolic syndrome and type 2 diabetes. Therefore, it is important to exclude the possibility of diabetes in those individuals with evidence of fatty liver. The global diabetes epidemic continues to grow, and it is estimated that the number of people with diabetes will double by year 2030. NAFLD is also a risk factor for an increase in cardiovascular incidence independent of age, sex, low-density lipoprotein-cholesterol, smoking, and cluster of metabolic syndromes. It is expected that NAFLD will be an important challenge for health providers in the near future. Taking all these factors into consideration, we believe that increasing awareness of metabolic and cardiovascular impact of NAFLD among general practitioners and health authorities may decrease the serious consequences of late diagnosis of NAFLD. Importantly, the collaboration between medical specialties is vital in decreasing the impact of the epidemic of NAFLD. The focus of this review is in the role of primary care physician in diagnosis, treatment and prevention of NAFLD and patients education.

Nonalcoholic fatty liver disease as a potential risk factor of cardiovascular disease

Nonalcoholic fatty liver disease (NAFLD) is the hepatic component of the metabolic syndrome. The aim of this review is to summarize the available data linking NAFLD with cardiovascular disease (CVD). The following topics are reviewed: (a) the clinical evidence linking NAFLD to increased prevalence of CVD; (b) the relationship between NAFLD (which is diagnosed by liver biopsy, serum liver enzymes, or ultrasonography) and incidence of CVD; (c) the mechanism linking NAFLD to CVD and clinical implication; and (d) the potential impact of NAFLD treatment on cardiac complications. CVD dictates the outcome (or outcomes) in patients with NAFLD more frequently and to a greater extent than does the progression of liver disease. NAFLD patients have a higher risk of all-cause death than the general population, mainly because of CVD or liver-related causes. The biologic mechanism linking NAFLD and CVD might be associated with various factors, involving a complex interaction among insulin resistance, oxidative stress, abnormal adipocytokine profile, endothelial dysfunction, lipid abnormalities, and activation of inflammatory cascade. Lifestyle modifications and pharmacotherapy are helpful to treat patients with NAFLD. NAFLD is likely to be associated with an increased risk of CVD, and raises the possibility that NAFLD may not only be a marker but also an early mediator of CVD.

Non-alcoholic Fatty Liver Disease and Metabolic Syndrome-Position Paper of the Indian National Association for the Study of the Liver, Endocrine Society of India, Indian College of Cardiology and Indian Society of Gastroenterology

Non-alcoholic fatty liver disease (NAFLD) is closely associated with metabolic syndrome. Prevalence of metabolic risk factors including diabetes mellitus, obesity, etc. is rapidly increasing in India putting this population at risk for NAFLD. Patients with NAFLD are at increased risk for liver-related morbidity and mortality and also cardiovascular disease risk and increased incidence of diabetes mellitus on long-term follow-up. Management of patients with NAFLD may require a multi-disciplinary approach involving not only the hepatologists but also the internists, cardiologists, and endocrinologists. This position paper which is a combined effort of the Indian National Association for Study of the Liver (INASL), Endocrine Society of India (ESI), Indian College of Cardiology (ICC) and the Indian Society of Gastroenterology (ISG) defines the spectrum of NAFLD and the association of NAFLD with insulin resistance and metabolic syndrome besides suggesting preferred approaches for the diagnosis and management of patients with NAFLD in the Indian context.

Effects of ursodeoxycholic acid therapy on carotid intima media thickness, apolipoprotein A1, apolipoprotein B, and apolipoprotein B/A1 ratio in nonalcoholic steatohepatitis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a prevalent liver disease that is increasingly being associated with cardiovascular disease. Ursodeoxycholic acid (UDCA) may have antioxidant and anti-inflammatory activities, and may reduce liver injury in NASH. To date, no studies have assessed the efficacy of UDCA in carotid intima media thickness (CIMT), serum lipids, apolipoprotein A1 (apo A), apolipoprotein B (apo B), and apolipoprotein B/A1 (apo B/A1) ratios in patients with NASH.

PATIENTS AND METHODS

In this prospective study, 30 patients with biopsy-proven NASH and 25 healthy adults as a control group were evaluated. None of the participants had diabetes, hypertension, or hyperlipidemia. Patients with NASH received UDCA 15 mg/kg/day for 6 months. BMI, waist circumference, homeostasis model assessment, lipids, apo A1, apo B, apo B/A1 ratios, and CIMT were analyzed before and after the treatment period.

RESULTS

At the end of the study, there were no statistically significant changes in BMI or waist circumference. Liver enzymes decreased gradually. The homeostasis model assessment decreased from 3.4 ± 1.89 to 2.06 ± 1.68 (P < 0.001). No significant changes in the mean triglyceride, total cholesterol, low-density lipoprotein, or apo B levels were observed. The mean high-density lipoprotein (42.9 ± 7.1 vs. 45.5 ± 9.8; P = 0.037) and apo A1 (127.6 ± 17.7 vs. 135.9 ± 22.2; P = 0.02) increased significantly. Apo B/A1 ratios tended to decrease, but this decrease was not statistically significant. The mean CIMT decreased significantly (0.56 ± 0.15 vs. 0.47 ± 0.12; P = 0.001).

CONCLUSION

UDCA treatment in NASH patients resulted in statistically significant reductions in the mean CIMT over a 6-month period. We believe that this benefit of UDCA may have resulted from decreased insulin resistance and increased serum high-density lipoprotein-apo A1 levels. However, larger, longer-term studies are needed to confirm this effect of UDCA in NASH.

Performance and limitations of steatosis biomarkers in patients with nonalcoholic fatty liver disease

BACKGROUND

Several steatosis biomarkers are available with limited independent validation.

AIM

To determine diagnostic value and limitations of several steatosis biomarkers using liver biopsy as reference standard in a large cohort of patients with suspected NAFLD.

METHODS

Three hundred and twenty-four consecutive liver biopsies were included. Histological steatosis was categorised as none (<5%), mild (5-33%), moderate (33-66%) and severe (>66%). Five steatosis biomarkers were measured: fatty liver index (FLI), NAFLD liver fat score (NAFLD-LFS), hepatic steatosis index (HSI), visceral adiposity index (VAI) and triglyceride × glucose (TyG) index.

RESULTS

Steatosis grades prevalence was: none 5%, mild 39%, moderate 30% and severe 27%. Except for VAI, the steatosis biomarkers showed a linear trend across the steatosis grades. However, their correlation with the histological amount of steatosis was only weak-moderate. All steatosis biomarkers had an adequate diagnostic accuracy for the presence of steatosis: AUROCs for FLI, LFS, HSI, VAI and TyG were 0.83, 0.80, 0.81, 0.92 and 0.90. However, their ability to quantify steatosis was poor: none of them distinguished between moderate and severe steatosis and the AUROCs for predicting steatosis >33% were 0.65, 0.72, 0.65, 0.59 and 0.59 for FLI, LFS, HSI, VAI and TyG. Both fibrosis and inflammation significantly confounded the association between steatosis biomarkers and steatosis. The steatosis biomarkers were all correlated with HOMA-IR, independent from histological steatosis.

CONCLUSIONS

All five steatosis biomarkers can diagnose steatosis and are correlated with insulin resistance. They are confounded by fibrosis and inflammation, and do not accurately quantify steatosis; this may limit their clinical utility. More research is needed to identify truly independent and quantitative markers of steatosis.

Association of ALT and the metabolic syndrome among Mexican children

Nonalcoholic fatty liver disease (NAFLD) is emerging as a component of the metabolic syndrome (MetS); Hispanics being particularly predisposed. Alanine aminotransferase (ALT) is considered a marker of NAFLD. The aim of this study was to determine the prevalence and associations between ALT elevations and MetS in normal-weight, overweight and obese Mexican children and adolescents, since data in Mexico is scarce. Body mass index (BMI), waist circumference (WC), percentage body fat, blood pressure, glucose, lipid profiles, ALT and aspartate aminotransferase (AST) were measured in 236, 6-12yo normal-weight, overweight and obese Mexicans from eight public schools. The results showed that elevated ALT (>40 IU/L) was found in 17.7% of the obese and overweight population, with no gender difference. The prevalence of elevated ALT increased linearly across BMI categories (p = 0.001), from 0.0% for the normal-weight group (95%CI 0.0-€“8.0) to 22.4% for the obese one (95%CI 16.2-€“30.2). AST/ALT ratio <1 also increased linearly, as did the prevalence of MetS (p = 0.001), from 0.0% for the normal-weight group to 40.3% for the obese one. The prevalence of MetS was strongly associated with elevated ALT (p = 0.002), 50% in the elevated ALT group (95%CI 34.1-€“65.9) and 24.1% in the normal ALT one (95%CI 18.1-€“31.3). There was also a strong association between MetS and an AST/ALT ratio <1. WC was the best predictor of elevated ALT (AOR = 7.13). Pearson correlation showed that MetS components were significantly correlated with elevated ALT. Therefore elevated ALT levels were highly prevalent and strongly associated with MetS in Mexican children, it should be screened in overweight and obese children.

Associations between nonalcoholic fatty liver disease and subclinical atherosclerosis in middle-aged adults: the Coronary Artery Risk Development in Young Adults Study

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is an obesity-related condition associated with cardiovascular mortality. Yet, whether or not NAFLD is independently related to atherosclerosis is unclear. In a population-based cross-sectional sample of middle-aged adults free from liver or heart disease, we tested the hypothesis that NAFLD is associated with subclinical atherosclerosis (coronary artery (CAC) and abdominal aortic calcification (AAC)) independent of obesity.

METHODS

Participants from the Coronary Artery Risk Development in Young Adults study with CT quantification of liver fat, CAC and AAC were included (n = 2424). NAFLD was defined as liver attenuation ≤40 Hounsfield Units after exclusion of other causes of liver fat. CAC and AAC presence was defined as Agatston score >0.

RESULTS

Mean participant age was 50.1 ± 3.6 years, (42.7% men, 50.0% black) and BMI was 30.6 ± 7.2 kg/m(2). The prevalence of NAFLD, CAC, and AAC was 9.6%, 27.1%, and 51.4%. NAFLD participants had increased prevalence of CAC (37.9% vs. 26.0%, p < 0.001) and AAC (65.1% vs. 49.9%, p < 0.001). NAFLD remained associated with CAC (OR, 1.33; 95% CI, 1.001-1.82) and AAC (OR, 1.74; 95% CI, 1.29-2.35) after adjustment for demographics and health behaviors. However, these associations were attenuated after additional adjustment for visceral adipose tissue (CAC OR, 1.05; 95% CI, 0.74-1.48, AAC OR = 1.20; 95% CI, 0.86-1.67). There was no interaction by race or sex.

CONCLUSION

In contrast to prior research, these findings suggest that obesity attenuates the relationship between NAFLD and subclinical atherosclerosis. Further studies evaluating the role of NAFLD duration on atherosclerotic progression and cardiovascular events are needed.

Hepatitis C virus infection and coronary artery disease risk: a systematic review of the literature

BACKGROUND AND AIMS

While hepatitis C virus (HCV) infection has been implicated in increasing the risk of coronary artery disease (CAD), conflicting reports exist regarding this association. We performed a systematic review to further investigate this association.

METHODS

We conducted a PubMed search of original research articles from January 1, 1995 to June 30, 2013 to identify case-control and cohort studies evaluating the association between HCV and CAD using keyword terms ["hepatitis c" or "HCV"] and ["coronary artery disease" or "heart disease" or "atherosclerosis."] The primary CAD-related endpoints included myocardial infarction, congestive heart failure, need for coronary artery bypass grafting, or transluminal percutaneous coronary angioplasty. Binary outcomes are reported as odds ratios (OR) with 95 % confidence interval (CI).

RESULTS

We identified five studies (four cohort studies and one case-control study) that met our inclusion criteria. A significant association between HCV and CAD was demonstrated in one cohort study (adjusted HR 1.27; 95 % CI 1.22-1.31). One cohort study demonstrated a decreased risk of CAD associated with HCV (adjusted OR 0.74; 95 % CI 0.71-0.76). The remaining studies did not find a significant association between HCV and risk of CAD.

CONCLUSIONS

The current systematic review demonstrates that the association between HCV and CAD remains unclear. We need more large, long-term cohort studies with clear definitions of patient population and endpoints to better ascertain the association between HCV and CAD.

From NAFLD to Cardiovascular Disease. Is it (Still) the Metabolic Syndrome?

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease in developed countries. The incidence of NAFLD in the general population is 30–38% deppending on the geographical area and the diagnostic method used. NAFLD is considered to be the liver manifestation of the metabolic syndrome. A better understanding of the natural evolution would have practical consequences related mainly to the need of early and aggressive diagnosis, active monitoring and therapeutic solutions. Cardiovascular disease appears to be the main cause of death in these patients. The mechanisms linking NAFLD with cardiovascular disease are not fully understood yet, but attention was focused primarily on insulin resistance. The visceral adipose tissue, the epicardial adipose tissue, the systemic inflammatory response syndrome, the lipid profile, the procoagulants factors, the oxidative stress, and type 2 diabetes mellitus, they all might play a role in the link between NAFLD and cardiovascular disease. Currently, there isn’t any medication specifically recommended for the treatment of NAFLD. Although the mechanisms underlying the association between NAFLD and cardiovascular disease are not fully known, attention must be paid to this association, given that these patients are more likely to die due to heart disease rather than liver disease.

The interactions of nonalcoholic fatty liver disease and cardiovascular diseases

A complex interaction among metabolic factors, adipose tissue lipolysis, oxidative stress, and insulin resistance results in a deleterious process that may link nonalcoholic fatty liver disease (NAFLD) with severe cardiovascular (CV) outcomes. Patients with NAFLD are at higher risk of atherosclerosis, new onset of CV events, and overall mortality. The strong association between NAFLD and CV disease should affect clinical practice, with screening and surveillance of patients with NAFLD. This review discusses the data linking these major diseases.

The Role of Non-alcoholic Fatty Liver Disease in Cardiovascular Disease

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease in western countries and is closely related to the metabolic syndrome. When NAFLD is associated with hepatocellular damage and inflammation (non-alcoholic steatohepatitis [NASH]) it can lead to severe liver disease. However, it has become clear that NAFLD is also associated with an increased risk of cardiovascular disease (CVD), independently of classical known risk factors for the latter. In the current review we briefly summarise the current clinical evidence on the role of NAFLD in CVD and discuss the potential mechanisms by which NAFLD can be linked to the pathophysiology of CVD.

Hard clinical outcomes in patients with NAFLD

Non-alcoholic fatty liver disease (NAFLD), once regarded as an innocuous condition, is now considered to be the most common cause of chronic liver disease worldwide. Evidence suggests a strong association between NAFLD and other potentially life-threatening diseases. A significant proportion of these patients develops progressive liver injury leading to cirrhosis and hepatocellular carcinoma. Unrecognized NAFLD constitutes a substantial proportion of patients with cryptogenic cirrhosis. Several large community-based studies have found increased mortality in NAFLD patients compared to the expected mortality of the general population of the same age and sex. Cardiovascular disease is an important cause of morbidity and mortality in patients with NAFLD and accounts for up to 30 % of overall death. Cardiovascular mortality does not seem to differ between simple steatosis and non-alcoholic steatohepatitis. NAFLD is associated with increased risk of both hepatic and extra-hepatic malignancy. Malignancy is among the most important causes of death in NAFLD patients. NAFLD is a risk factor for liver cancer even without cirrhosis. The steatotic liver has poor ability to regenerate after volume loss, which may lead to the development of liver failure and increased mortality after extended liver resection. Also, transplantation of steatotic liver results in an increased rate of poor graft function, primary graft non-function, and poorer outcome. There is a high recurrence rate of fatty liver disease in patients transplanted for NASH.

A systematic review: burden and severity of subclinical cardiovascular disease among those with nonalcoholic fatty liver; should we care?

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an emerging disease and a leading cause of chronic liver disease. The prevalence in the general population is approximately 15-30% and it increases to 70-90% in obese or diabetic populations. NAFLD has been linked to increased cardiovascular disease (CVD) risk. It is therefore critical to evaluate the relationship between markers of subclinical CVD and NAFLD.

METHOD

An extensive search of databases; including the National Library of Medicine and other relevant databases for research articles meeting inclusion criteria: observational or cohort, studies in adult populations and clearly defined NAFLD and markers of subclinical CVD.

RESULTS

Twenty-seven studies were included in the review; 16 (59%) presented the association of NAFLD and carotid intima-media thickness (CIMT), 7 (26%) the association with coronary calcification and 7 (26%) the effect on endothelial dysfunction and 6 (22%) influence on arterial stiffness. CIMT studies showed significant increases among NAFLD patients compared to controls. These were independent of traditional risk factors and metabolic syndrome. The association was similar in coronary calcification studies. The presence of NAFLD is associated with the severity of the calcification. Endothelial dysfunction and arterial stiffness showed significant independent associations with NAFLD. Two studies argued the associations were not significant; however, these studies were limited to diabetic populations.

CONCLUSION

There is evidence to support the association of NAFLD with subclinical atherosclerosis independent of traditional risk factors and metabolic syndrome. However, there is need for future longitudinal studies to review this association to ascertain causality and include other ethnic populations.

Progression of NAFLD to diabetes mellitus, cardiovascular disease or cirrhosis

NAFLD is a spectrum of progressive liver disease that encompasses simple steatosis, NASH, fibrosis and, ultimately, cirrhosis. NAFLD is recognized as the hepatic component of the metabolic syndrome, as these conditions have insulin resistance as a common pathophysiological mechanism. Therefore, NAFLD is strongly associated with type 2 diabetes mellitus and abdominal obesity. As lifestyles have become increasingly sedentary and dietary patterns have changed, the worldwide prevalence of NAFLD has increased dramatically and is projected to be the principal aetiology for liver transplantation within the next decade. Importantly, a growing body of clinical and epidemiological evidence suggests that NAFLD is associated not only with liver-related morbidity and mortality, but also with an increased risk of developing both cardiovascular disease and type 2 diabetes mellitus. This article reviews the evidence that suggests NAFLD is a multisystem disease and the factors that might determine interindividual variation in the development and progression of its major hepatic and extrahepatic manifestations (principally type 2 diabetes mellitus and cardiovascular disease).

Hepatic steatosis is associated with aortic valve sclerosis in the general population: the Study of Health in Pomerania (SHIP)

OBJECTIVE

We aimed to analyze the association between hepatic steatosis and aortic valve sclerosis in the general population.

APPROACH AND RESULTS

Cross-sectional data of 2212 men and women, aged 45 to 81 years, from the baseline examination of the population-based Study of Health in Pomerania (SHIP-0) were analyzed. Hepatic steatosis was primarily defined as the presence of a hyperechogenic ultrasound pattern of the liver. Aortic valve sclerosis was determined by echocardiography. In our sample, hepatic steatosis was present in 877 (39.7%) individuals. Among participants with hepatic steatosis, aortic valve sclerosis was more common (n=323; 36.8%) compared with participants without hepatic steatosis (n=379; 28.4%; P<0.001). After adjustment for potential confounders, individuals with hepatic steatosis had 33% higher odds of aortic valve sclerosis compared with those without hepatic steatosis (95% confidence interval, 6%-66%; P=0.014). Additional adjustment for high-sensitive C-reactive protein, serum ferritin levels, and white blood cells slightly reduced the association to 32% (95% confidence interval, 4%-66%; P=0.021).

CONCLUSIONS

Our findings add evidence that hepatic steatosis and aortic valve sclerosis are interrelated after adjustment for major confounders. The release of proatherogenic substances by the steatotic liver or its contribution to insulin resistance and dyslipidemia may contribute to the development of calcification and sclerosis of the aortic valve.

Fatty liver is a good indicator of subclinical atherosclerosis risk in obese children and adolescents regardless of liver enzyme elevation

AIM

To investigate the presence of association between nonalcoholic fatty liver disease (NAFLD) and subclinical atherosclerosis using carotid intima media thickness (c-IMT) in obese children and adolescents. Additionally, we wished to investigate the relationship between fatty liver and elevated liver enzymes.

METHODS

A total of 157 obese patients (78 boys and 79 girls, mean age: 11.3 ± 2.6 years, age range: 6-16 years) were enrolled in the study. Aminotransferase, fasting glucose and lipid levels were determined. An oral glucose tolerance test was performed. The c-IMT was measured. Infectious and metabolic causes of elevated liver enzymes were excluded. The diagnosis of NAFLD was based on ultrasound scan.

RESULTS

Obese patients with NAFLD had markedly increased carotid IMT (mean: 0.48 mm, 95% CI: 0.47-0.49) than those without NAFLD (mean: 0.45 mm 95% CI: 0.44-0.45, p < 0.001). The presence of NAFLD significantly increased c-IMT whether the patient had elevated liver enzyme or not (ANOVA, p < 0.001). In a multiple-regression model, only the presence of NAFLD was associated with increased c-IMT (β = 0.031, SE (β) = 0.008, p < 0.001).

CONCLUSION

Obese children and adolescents with NAFLD are at risk of early atherosclerotic changes. As liver function tests are not sufficient to identify patients with fatty liver, ultrasonographic evaluation of NAFLD might be considered in all obese children and adolescents.

Association of proinsulin and hepatic steatosis in a random, population-based sample

OBJECTIVE

Proinsulin may represent a predictive marker for assessing insulin resistance and reduced β-cell function. The objective of this study was to investigate the association between hepatic steatosis, proinsulin and other parameters in a random, population-based sample.

DESIGN

Cross-sectional study, conducted in south-western Germany.

METHODS

Upper abdominal ultrasound examinations were performed in 343 subjects (147 females, 196 males; average age 40.0±11.5 years). Proinsulin, the proinsulin-to-insulin ratio and other laboratory parameters were determined, and the BMI, waist-to-hip ratio (WHR) and other anthropometric data were documented.

RESULTS

HEPATIC STEATOSIS WAS OBSERVED IN 80 SUBJECTS (23.3%: 29.6%, males; 15.0%, females). Multivariate analysis showed an association with hepatic steatosis for male gender (P=0.0212), advancing age (P=0.0241), elevated BMI (P<0.0001), elevated WHR (P=0.0024), alanine aminotransferase (P=0.0046), proinsulin (P=0.0403) and proinsulin-to-insulin ratio (P=0.0116).

CONCLUSIONS

There is an association between elevated proinsulin concentrations and hepatic steatosis.

Diabetes and nonalcoholic Fatty liver disease: a pathogenic duo

Recent data increasingly support a complex interplay between the metabolic condition diabetes mellitus and the pathologically defined nonalcoholic fatty liver disease (NAFLD). NAFLD predicts the development of type 2 diabetes and vice versa, and each condition may serve as a progression factor for the other. Although the association of diabetes and NAFLD is likely to be partly the result of a "common soil," it is also probable that diabetes interacts with NAFLD through specific pathogenic mechanisms. In particular, through interrelated metabolic pathways currently only partly understood, diabetes appears to accelerate the progression of NAFLD to nonalcoholic steatohepatitis, defined by the presence of necroinflammation, with varying degrees of liver fibrosis. In the research setting, obstacles that have made the identification of clinically significant NAFLD, and particularly nonalcoholic steatohepatitis, difficult are being addressed with the use of new imaging techniques combined with risk algorithms derived from peripheral blood profiling. These techniques are likely to be used in the diabetes population in the near future. This review examines the pathogenic links between NAFLD and diabetes by exploring the epidemiological evidence in humans and also through newer animal models. Emerging technology to help screen noninvasively for differing pathological forms of NAFLD and the potential role of preventive and therapeutic approaches for NAFLD in the setting of diabetes are also examined.

The association between non-alcoholic fatty liver disease and carotid atherosclerosis in subjects with within-reference range alanine aminotransferase levels

Our aim was to investigate whether the evaluation of non-alcoholic fatty liver disease (NAFLD) by ultrasound provides additional benefit in assessing carotid atherosclerotic burden in subjects with alanine aminotransferase (ALT) concentrations within the reference range. This was a cross-sectional analysis of 769 healthy individuals (326 men and 443 women) with an ALT concentration ≤ 40 IU/L and alcohol consumption < 140 g/week. Mean carotid artery intima-media thickness (C-IMT) was measured using ultrasound. NAFLD was defined as a mild or greater degree of hepatic steatosis on ultrasound. Although all subjects had an ALT concentration within the reference range, the prevalence of NAFLD increased with increasing quartiles of ALT concentration (27.1%, 40.0%, 54.7%, 75.3% in men, P for trend < 0.001; 22.0%, 34.4%, 35.7%, 55.0% in women, P for trend < 0.001). In the 3rd and 4th quartiles of ALT concentration, women with NAFLD had a significantly higher C-IMT than those without NAFLD (0.671±0.019 mm vs. 0.742±0.025 mm, P=0.023 in Q3; 0.651±0.023 mm vs. 0.737±0.021 mm, P=0.005 in Q4). These differences remained significant even after adjusting for a broad spectrum of potential confounders. In contrast, although men with NAFLD tended to have a higher C-IMT than those without NAFLD in each quartile, these differences were not statistically significant. Women with an upper normal range ALT concentration showed increased C-IMT only when they had NAFLD. Therefore, in women with an elevated ALT level within the reference range, further evaluation for NAFLD, such as liver ultrasound, could potentially identify those patients at high risk for cardiovascular disease.

A Study of Carotid Atherosclerosis in Patients with Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease shares many features of metabolic syndrome and its presence could signify a substantial cardiovascular risk above and beyond that conferred by individual risk factors. This study is an attempt to investigate the association of non-alcoholic fatty liver disease with carotid intima-media thickness and plaque as surrogate measures of increased cardiovascular risk. The study was conducted on 645 non diabetic, non alcoholic subjects in the age range of 20-60 years. Metabolic syndrome was assessed by using ATP III and ADA (2005) criteria. Anthropometric factors-waist circumference and blood pressure were measured. Fasting serum samples were analyzed for glucose, triglyceride, cholesterol and its fractions, insulin, alanine and aspartate transaminases, gamma glutamyl transferase and free fatty acids. Insulin resistance and secretion were calculated by homeostasis model and insulin sensitivity by QUICKI index. Liver ultrasonographic scanning was used for assessing fatty liver. Carotid atherosclerosis was assessed by B-mode ultrasonography of common carotid artery and internal carotid artery. The prevalence of non-alcoholic fatty liver disease was 15.6 % in non alcoholic population and 68.5 % of non-alcoholic fatty liver disease had metabolic syndrome, which was associated with hyperinsulinemia, insulin resistance, insulin insensitivity along with elevated levels of waist circumference, blood pressure, triglyceride, FFA and decreased HDL cholesterol. NAFLD patients had markedly greater carotid intima media thickness than non NAFLD subjects with MCIMT of 591.6 ± 108 and 489.5 ± 132.4 μm (P < 0.001) and plaque prevalence of 19.2 and 2.2 %, respectively, thus the carotid intima media thickness is associated with NAFLD.

Non-alcoholic fatty liver disease and cardiovascular risk

The term "Non-alcoholic fatty liver disease" (NAFLD) covers a series of liver lesions similar to those induced by alcohol, but not caused by alcohol use. The importance of NAFLD lies in the high prevalence in Western societies and, from the point of view of the liver, in its progression from steatosis to cirrhosis and liver cancer. More recently, NAFLD has been found to be associated with lipid metabolism disorders, the deposition of fat outside of the adipocytes, insulin resistance and Metabolic Syndrome. Also attributed to NAFLD is a heightened systemic pro-inflammatory state, which accelerates arteriosclerosis, thereby increasing cardiovascular risk and associated cardiovascular events. Here we provide an update to the etiopathogenesis of NAFLD, its influence on cardiovascular disease, and the treatment options.

R2* estimation using "in-phase" echoes in the presence of fat: the effects of complex spectrum of fat

PURPOSE

To investigate R2* mapping robustness in the presence of fat using in-phase echoes, without and with spectral modeling of fat (single-peak and multipeak models, respectively), using varying numbers of echoes.

MATERIALS AND METHODS

Data from 88 volunteers (men/women: 52/36, ages: 55.4 ± 12.2) were randomly chosen according to magnetic resonance imaging (MRI) liver fat-fraction (%), and classified into six fat-fraction groups (1: 20 cases, 0%-<10%; 2: 20 cases, 10%-<20%; 3: 20 cases, 20%-<30%; 4: 20 cases, 30%-<40%; 5: 8 cases >40% liver fat; 6: subcutaneous fat from all cases). R2* maps obtained from five in-phase echoes (echo times: 4.8-23.8 msec) were retrospectively reconstructed using single-peak and multipeak fat modeling. R2* maps were also calculated using different numbers (2-5) of echoes.

RESULTS

Multipeak fat corrected R2* mapping is feasible from in-phase echoes, with noise performance comparable to single-peak R2* when using ≥ 4 echoes. Single-peak R2* showed poor robustness to varying echo time combinations in the presence of fat, where using few echoes resulted in large errors. These errors can be reduced using more echoes, or fully corrected using multipeak fat modeling. The mean R2* increased significantly with increasing fat-fraction when using single-peak R2* for any TE combination (P < 0.001), but did not vary when using multipeak R2* for any TE combination (P ≥ 0.158).

CONCLUSION

R2* mapping uncorrected for spectral complexity of fat contains protocol and fat-dependent errors (lack of robustness) in tissues with high fat content. Accounting for complex fat spectrum improves robustness and accuracy of signal fitting, with modest noise performance loss.

Non-alcoholic fatty liver disease and cardiovascular disease: epidemiological, clinical and pathophysiological evidences

Non-alcoholic fatty liver disease is recognized as the most common and emerging chronic liver disease in western countries. The disease has been traditionally interpreted as a possibly progressing condition to liver fibrosis and cirrhosis. However, recently, a large number of publications have demonstrated that people with non-alcoholic fatty liver have an increased chance of developing cardiovascular diseases, which represent the major causes of death in this setting. This association is mainly explained by the atherogenic profile of the metabolic syndrome a condition frequently associated with fatty liver, which may represent its hepatic component. Some studies have also shown an association independent of traditional risk factors or of the clinical features of the metabolic syndrome. In this setting, cardiovascular disease seems to be the consequence of low-grade chronic inflammation and increased oxidative stress. Most studies did not differentiate cardiovascular risk between simple steatosis and non-alcoholic steatohepatitis, although the latter seems to be at higher cardiovascular risk. Few studies have investigated the direct correlation between hepatic inflammation and atherosclerosis. Genetic studies will probably improve the interpretation of the increased cardiovascular risk in patients with fatty liver and no metabolic syndrome.

Relationship between Nonalcoholic Fatty Liver Disease and Carotid Artery Atherosclerosis Beyond Metabolic Disorders in Non-Diabetic Patients

Background

The objective of this study was to investigate the association between nonalcoholic fatty liver disease (NAFLD) and carotid artery atherosclerosis beyond metabolic disorders.

Methods

We studied 320 non-diabetic patients with ultrasonographically diagnosed NAFLD and 313 non-diabetic patients without NAFLD who have less than 40 g alcohol/week drinking history. Carotid atherosclerotic burden was assessed by carotid intima-media thickness (IMT) and plaque. All subjects were divided to the metabolic syndrome (MetS) according to International Diabetes Federation criteria.

Results

NAFLD patients had a significantly increased mean carotid IMT (0.79 ± 0.18 vs. 0.73 ± 0.13 mm; p < 0.001) than those without the condition. The prevalence of increased IMT, defined as IMT ≥ 1 mm, and carotid plaque were 52.5% and 34.1% in the patients with NAFLD vs. 35.8% and 18.8% in the patients without this condition (p < 0.001). The difference in IMT and prevalence of plaque was also significant even in patients without MetS as well as those with MetS (all p < 0.05). NAFLD-associated adjusted odds ratio for increased IMT was 1.236 [95% confidence interval (CI), 1.023-1.467, p = 0.016] without MetS and 1.178 (95% CI, 1.059-1.311, p = 0.003) with MetS. NAFLD-associated adjusted odds ratio of carotid plaque was 1.583 (95% CI, 1.309-1.857, p = 0.024) without MetS and 1.536 (95% CI, 0.512-4.604, p = 0.444) with MetS.

Conclusion

NAFLD is significantly associated with carotid atherosclerosis in non-diabetic outpatients even without MetS. Carotid screening for NAFLD might be beneficial for assessment of future atherosclerotic complications.

Carotid intima-media thickness and liver histology in hemodialysis patients with nonalcoholic Fatty liver disease

The prevalence of atherosclerotic cardiovascular disease in chronic hemodialysis (HD) patients has been demonstrated to be higher than in healthy people. Severe liver fibrosis is strongly associated with early carotid atherosclerosis and it might reduce the survival of patients who undergo both renal replacement therapy and transplantation. We wanted to assess whether nonalcoholic fatty liver disease (NAFLD) was associated with altered intima-media thickness (IMT) in HD patients as an independent marker of subclinical atherosclerosis. We enrolled 42 patients undergoing HD and 48 patients with normal renal function, all of them with high levels of aminotransferases and an ultrasonographic diagnosis of liver steatosis. The control group consisted of 60 healthy subjects. Laboratory tests for inflammatory and oxidative markers, ultrasonographic liver evaluation, carotid IMT measurement, and liver biopsy were performed. Different degrees of fibrosis were detected in our study cohort. Worse liver histopathological scores and higher plasmatic levels of C-reactive protein, reactive oxygen species, and vascular cell adhesion molecule-1 were found in HD patients. Carotid IMT was significantly higher (p < 0.005) in patients with histological steatosis. HD patients may develop active and progressive chronic hepatitis faster than patients with normal renal function and the thickness of their carotid intima-media might be markedly increased. These two conditions seem to be independent on classical risk factors and on metabolic syndrome. They might be related to the high levels of oxidants and to the inflammatory state, which are typical of patients undergoing HD. Independently related with the traditional risk factors for cardiovascular disease, nonspecific inflammation and oxide-reductive imbalance may play an important role in the progression of NAFLD and atherosclerotic disease in HD patients.

Multicausality in fatty liver disease: Is there a rationale to distinguish between alcoholic and non-alcoholic origin?

Apart from alcohol, there are other factors that may induce complications, which resemble alcohol-related liver disorders. In particular, obesity has been brought into focus as a risk factor for fatty liver disease. The term “non-alcoholic” fatty liver disease is commonly used to distinguish between obesity-related and alcohol-related hepatic steatosis. This review uses the epidemiological perspective to critically assess whether it is necessary and useful to differentiate between alcoholic and “non-alcoholic” fatty liver disease. The MEDLINE database was searched using the PubMed search engine, and a review of reference lists from original research and review articles was conducted. The concept to distinguish between alcoholic and “non-alcoholic” fatty liver disease is mainly based on specific pathomechanisms. This concept has, however, several limitations including the common overlap between alcohol misuse and obesity-related metabolic disorders and the non-consideration of additional causal factors. Both entities share similar histopathological patterns. Studies demonstrating differences in clinical presentation and outcome are often biased by selection. Risk factor reduction is the main principle of prevention and treatment of both disease forms. In conclusion, alcoholic and “non-alcoholic” fatty liver diseases are one and the same disease caused by different risk factors. A shift from artificial categories to a more general approach to fatty liver disease as a multicausal disorder may optimize preventive strategies and help clinicians more effectively treat patients at the individual level.

Evaluation of relationship between grading of fatty liver and severity of atherosclerotic finding

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is a feature of metabolic syndrome and has a high prevalence in the general population.

OBJECTIVE

To determine the severity of atherosclerotic finding in various grade of NAFLD.

MATERIAL AND METHODS

We examined 250 consecutive patients with various grade of NAFLD and 85 control subjects matched for age, gender, to determine carotid intima-media thickness (CIMT) in each groups.

RESULTS

The mean CIMT in patients with G1, G2 and G3 NAFLD were 0.78±0.15 mm, 0.82±0.11mm and 0.85±0.16mm respectively. The differences in CIMT between the various grades of NAFLD were statistically significant (p=0.01).

CONCLUSION

According to our study results the presence of NAFLD; severity of atherosclerosis will be higher parallel with severity of fatty liver infiltration. Therefore, Patients with NAFLD especially high-grade fatty liver may be candidate to be investigated for the presence CAD.

A low level of serum total testosterone is independently associated with nonalcoholic fatty liver disease

BACKGROUND

The association between low serum testosterone levels, visceral adipose tissue (VAT), and metabolic syndrome is now well known. However, the relationship between hepatic steatosis and serum testosterone levels has not been extensively studied. Our aim was to investigate the association of serum total testosterone levels with nonalcoholic fatty liver disease (NAFLD), adjusting for the influence of VAT and insulin resistance.

METHODS

This study is a retrospective observational cross-sectional one of healthy Korean men and was conducted at the Seoul National University Hospital Healthcare System Gangnam Center. We used data obtained from 495 men who were at least 20 years of age and who had undergone blood testing, abdominal computed tomography, and ultrasonography. Multiple logistic regression analysis was used to explore the association of serum total testosterone levels with NAFLD.

RESULTS

Men in the low serum testosterone quintile were at a higher risk for NAFLD than men in the highest serum testosterone quintile. After adjusting for age, smoking, diabetes, exercise, BMI, triglycerides, and high-density-lipoprotein cholesterol, subjects with serum testosterone levels in the lowest quintile had an odds ratio (OR) (95% confidence interval (CI)) of 5.12 (2.43-10.77) for NAFLD (p value, 0.0004). The inverse association between serum testosterone and NAFLD was attenuated by further adjustment for variables including VAT; however, it remained statistically significant (OR (95% CI): 4.52 (2.09-9.80) in the lowest quintile; p value=0.004).

CONCLUSIONS

A low serum total testosterone level was independently associated with NAFLD. This report is the first one suggesting the association remains unchanged even after controlling for VAT and insulin resistance.