Non-alcoholic fatty liver disease and cardiovascular risk: Pathophysiological mechanisms and implications

Hepatic fat is superior to BMI, visceral and pancreatic fat as a potential risk biomarker for neurodegenerative disease

OBJECTIVES

Prior studies relating body mass index (BMI) to brain volumes suggest an overall inverse association. However, BMI might not be an ideal marker, as it disregards different fat compartments, which carry different metabolic risks. Therefore, we analyzed MR-based fat depots and their association with gray matter (GM) volumes of brain structures, which show volumetric changes in neurodegenerative diseases.

METHODS

Warp-based automated brain segmentation of 3D FLAIR sequences was obtained in a population-based study cohort. Associations of temporal lobe, cingulate gyrus, and hippocampus GM volume with BMI and MR-based quantification of visceral adipose tissue (VAT), as well as hepatic and pancreatic proton density fat fraction (PDFF_hepatic and PDFF_panc, respectively), were assessed by linear regression.

RESULTS

In a sample of 152 women (age 56.2 ± 9.0 years) and 199 men (age 56.1 ± 9.1 years), we observed a significant inverse association of PDFF_hepatic and cingulate gyrus volume (p < 0.05) as well as of PDFF_hepatic and hippocampus volume (p < 0.05), when adjusting for age and sex. This inverse association was further enhanced for cingulate gyrus volume after additionally adjusting for hypertension, smoking, BMI, LDL, and total cholesterol (p < 0.01) and also alcohol (p < 0.01). No significant association was observed between PDFF_hepatic and temporal lobe and between temporal lobe, cingulate gyrus, or hippocampus volume and BMI, VAT, and PDFF_panc.

CONCLUSIONS

We observed a significant inverse, independent association of cingulate gyrus and hippocampus GM volume with hepatic fat, but not with other obesity measures. Increased hepatic fat could therefore serve as a marker of high-risk fat distribution.

KEY POINTS

• Obesity is associated with neurodegenerative processes. • In a population-based study cohort, hepatic fat was superior to BMI and visceral and pancreatic fat as a risk biomarker for decreased brain volume of cingulate gyrus and hippocampus. • Increased hepatic fat could serve as a marker of high-risk fat distribution.

Oophorectomy and risk of non-alcoholic fatty liver disease and primary liver cancer in the Clinical Practice Research Datalink

Incidence of non-alcoholic fatty liver disease (NAFLD) and liver cancer are 2-3 times higher in males than females. Hormonal mechanisms are hypothesized, with studies suggesting that oophorectomy may increase risk, but population-based evidence is limited. Thus, we conducted a study within the Clinical Practice Research Datalink, with controls matched to cases of NAFLD (n = 10,082 cases/40,344 controls) and liver cancer (n = 767 cases/3068 controls). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. Effect measure modification by menopausal hormone therapy (MHT) was examined, using likelihood ratio tests and relative excess risk due to interaction (RERI). Oophorectomy was associated with a 29% elevated NAFLD risk (OR = 1.29, 95% CI 1.18-1.43), which was more pronounced in women without diabetes (OR = 1.41, 95% CI 1.27-1.57) and in women who had oophorectomy prior to age 50 (OR = 1.37, 95% CI 1.22-1.52). Compared to women without oophorectomy or MHT use, oophorectomy and MHT were each associated with over 50% elevated risk of NAFLD. However, the combination of oophorectomy and MHT showed evidence of a negative interaction on the multiplicative (p = 0.003) and additive scales (RERI = - 0.28, 95% CI - 0.60 to 0.03, p = 0.08). Oophorectomy, overall, was not associated with elevated liver cancer risk (OR = 1.16, 95% CI 0.79-1.69). These findings suggest that oophorectomy may increase the risk of NAFLD, but not liver cancer.

Role of Myeloid-Epithelial-Reproductive Tyrosine Kinase and Macrophage Polarization in the Progression of Atherosclerotic Lesions Associated With Nonalcoholic Fatty Liver Disease

Recent lines of evidence highlight the involvement of myeloid-epithelial-reproductive tyrosine kinase (MerTK) in metabolic disease associated with liver damage. MerTK is mainly expressed in anti-inflammatory M2 macrophages where it mediates transcriptional changes including suppression of proinflammatory cytokines and enhancement of inflammatory repressors. MerTK is regulated by metabolic pathways through nuclear sensors including LXRs, PPARs, and RXRs, in response to apoptotic bodies or to other sources of cholesterol. Nonalcoholic fatty liver disease (NAFLD) is one of the most serious public health problems worldwide. It is a clinicopathological syndrome closely related to obesity, insulin resistance, and oxidative stress. It includes a spectrum of conditions ranging from simple steatosis, characterized by hepatic fat accumulation with or without inflammation, to nonalcoholic steatohepatitis (NASH), defined by hepatic fat deposition with hepatocellular damage, inflammation, and accumulating fibrosis. Several studies support an association between NAFLD and the incidence of cardiovascular diseases including atherosclerosis, a major cause of death worldwide. This pathological condition consists in a chronic and progressive inflammatory process in the intimal layer of large- and medium-sized arteries. The complications of advanced atherosclerosis include chronic or acute ischemic damage in the tissue perfused by the affected artery, leading to cellular death. By identifying specific targets influencing lipid metabolism and cardiovascular-related diseases, the present review highlights the role of MerTK in NAFLD-associated atherosclerotic lesions as a potential innovative therapeutic target. Therapeutic advantages might derive from the use of compounds selective for nuclear receptors targeting PPARs rather than LXRs regulating macrophage lipid metabolism and macrophage mediated inflammation, by favoring the expression of MerTK, which mediates an immunoregulatory action with a reduction in inflammation and in atherosclerosis.

Presence of diabetic retinopathy is lower in type 2 diabetic patients with non-alcoholic fatty liver disease

To analyze the association between non-alcoholic fatty liver disease (NAFLD) and the presence of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).Total 411 T2DM patients were divided into NAFLD and control groups. NAFLD was diagnosed by ultrasound. Retinopathy was diagnosed by fundus photography. All patients were screened based on medical history, physical examinations, and laboratory measurements.The prevalence of NAFLD and DR in T2DM patients was 60.8% and 40.9%, respectively. The presence of DR was associated with diabetes duration, systolic blood pressure (SBP), glycated hemoglobin (HbA1c), and proteinuria (all P < .001) using univariate and multivariate regression analyses. The prevalence of DR was lower in patients with NAFLD than those without NAFLD (37.2% vs 46.6%, P = .065), and significantly lower in patients with moderate and severe NAFLD (30.2% vs 46.6%, P = .012; 14.3% vs 46.6%, P = .024). The presence of DR in NAFLD patients was associated with diabetes duration (P = .032) in Chi-squared analysis.NAFLD and DR were highly prevalent in T2DM patients. Diabetes duration, SBP, HbA1c, and proteinuria were risk factors for DR in T2DM patients. The presence of DR was lower in T2DM patients with NAFLD, which was mainly due to their shorter diabetes duration.

A narrative review on effects of vitamin D on main risk factors and severity of Non-Alcoholic Fatty Liver Disease

The global prevalence of Non-alcoholic fatty liver disease (NAFLD) is increasing rapidly. Many studies have been conducted on the treatment of NAFLD; nevertheless, there is still no approved drug treatment for this disease. Although the pathogenesis of NAFLD is not fully understood, but inflammation, insulin resistance, oxidative stress, obesity and dyslipidemia are among the main causes. Epidemiological studies have shown that hypovitaminosis D is associated with these factors causing NAFLD. In addition, rate of Vitamin D deficiency has been shown to be directly related to the severity of NAFLD. Accordingly, it is believed that vitamin D may help to treatment of NAFLD by improving the above-mentioned risk factors. The purpose of this review is to survey the recent advances in the field of Vitamin D efficacy on risk factors and the severity of NAFLD based on existing evidence, especially the clinical efficiency of vitamin D supplementation in patients with NAFLD.

Pharmacological Treatment for Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has become the most frequently encountered chronic liver disease. NAFLD is associated with increased liver-related morbidity and mortality, but also contributes to cardiovascular disease, diabetes and non-liver-related malignancy. Non-alcoholic steatohepatitis (NASH) is considered the more severe subtype of NAFLD that drives most of these adverse outcomes. Lifestyle modification and associated weight loss can improve NASH but are not always sufficient and sustained results are difficult to obtain. There is hence an urgent need for pharmacological treatment. In this review we discuss some of the concepts and challenges in the development of pharmacological treatment. We also briefly summarise what can be achieved with some of the drugs that are currently available for other indications but have demonstrated benefit in the treatment of NASH. Finally we present an overview of some of the main drugs or types of drugs, mainly based on their mode of action, that are now being developed specifically to treat NASH and that might soon result in the availability of drugs licensed for NASH.

Diet-induced hepatic steatosis abrogates cell-surface LDLR by inducing de novo PCSK9 expression in mice

The worldwide prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing rapidly. Although this condition is generally benign, accumulating evidence now suggests that patients with NAFLD are also at increased risk of cardiovascular disease (CVD); the leading cause of death in developed nations. Despite the well-established role of the liver as a central regulator of circulating low-density lipoprotein (LDL) cholesterol levels, a known driver of CVD, the mechanism(s) by which hepatic steatosis contributes to CVD remains elusive. Interestingly, a recent study has shown that circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) levels correlate positively with liver steatosis grade. Given that PCSK9 degrades the LDL receptor (LDLR) and prevents the removal of LDL from the blood into the liver, in the present study we examined the effect of hepatic steatosis on LDLR expression and circulating LDL cholesterol levels. We now report that in a manner consistent with findings in patients, diet-induced steatosis increases circulating PCSK9 levels as a result of de novo expression in mice. We also report the finding that steatosis abrogates hepatic LDLR expression and increases circulating LDL levels in a PCSK9-dependent manner. These findings provide important mechanistic insights as to how hepatic steatosis modulates lipid regulatory genes, including PCSK9 and the LDLR, and also highlights a novel mechanism by which liver disease may contribute to CVD.

Angiopoietin-2 Promotes Pathological Angiogenesis and Is a Therapeutic Target in Murine Nonalcoholic Fatty Liver Disease

Angiogenesis contributes to the development of nonalcoholic steatohepatitis (NASH) and promotes inflammation, fibrosis, and progression to hepatocellular carcinoma (HCC). Angiopoietin-2 (Ang-2) is a key regulator of angiogenesis. We aimed to investigate the role of Ang-2 and its potential as a therapeutic target in NASH using human samples, in vivo mouse models, and in vitro assays. Serum Ang-2 levels were determined in 104 obese patients undergoing bariatric surgery and concomitant liver biopsy. The effect of the Ang-2/Tie2 receptor inhibiting peptibody L1-10 was evaluated in the methionine-choline deficient (MCD) and streptozotocin-western diet nonalcoholic fatty liver disease mouse models, and in vitro on endothelial cells and bone marrow-derived macrophages. The hepatic vasculature was visualized with µCT scans and scanning electron microscopy of vascular casts. Serum Ang-2 levels were increased in patients with histological NASH compared with patients with simple steatosis and correlated with hepatic CD34 immunoreactivity as a marker of hepatic angiogenesis. Serum and hepatic Ang-2 levels were similarly increased in mice with steatohepatitis. Both preventive and therapeutic L1-10 treatment reduced hepatocyte ballooning and fibrosis in MCD diet-fed mice and was associated with reduced hepatic angiogenesis and normalization of the vascular micro-architecture. Liver-isolated endothelial cells and monocytes from MCD-fed L1-10-treated mice showed reduced expression of leukocyte adhesion and inflammatory markers, respectively, compared with cells from untreated MCD diet-fed mice. In the streptozotocin-western diet model, therapeutic Ang-2 inhibition was able to reverse NASH and attenuate HCC progression. In vitro, L1-10 treatment mitigated increased cytokine production in lipopolysaccharide-stimulated endothelial cells but not in macrophages. Conclusion: Our findings provide evidence for Ang-2 inhibition as a therapeutic strategy to target pathological angiogenesis in NASH.

Macrophages in obesity and non-alcoholic fatty liver disease: Crosstalk with metabolism

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, and a major cause of liver cirrhosis and hepatocellular carcinoma. NAFLD is intimately linked with other metabolic disorders characterized by insulin resistance. Metabolic diseases are driven by chronic inflammatory processes, in which macrophages perform essential roles. The polarization status of macrophages is itself influenced by metabolic stimuli such as fatty acids, which in turn affect the progression of metabolic dysfunction at multiple disease stages and in various tissues. For instance, adipose tissue macrophages respond to obesity, adipocyte stress and dietary factors by a specific metabolic and inflammatory programme that stimulates disease progression locally and in the liver. Kupffer cells and monocyte-derived macrophages represent ontologically distinct hepatic macrophage populations that perform a range of metabolic functions. These macrophages integrate signals from the gut-liver axis (related to dysbiosis, reduced intestinal barrier integrity, endotoxemia), from overnutrition, from systemic low-grade inflammation and from the local environment of a steatotic liver. This makes them central players in the progression of NAFLD to steatohepatitis (non-alcoholic steatohepatitis or NASH) and fibrosis. Moreover, the particular involvement of Kupffer cells in lipid metabolism, as well as the inflammatory activation of hepatic macrophages, may pathogenically link NAFLD/NASH and cardiovascular disease. In this review, we highlight the polarization, classification and function of macrophage subsets and their interaction with metabolic cues in the pathophysiology of obesity and NAFLD. Evidence from animal and clinical studies suggests that macrophage targeting may improve the course of NAFLD and related metabolic disorders.

Immunoregulatory Effect of Koumine on Nonalcoholic Fatty Liver Disease Rats

Nonalcoholic fatty liver disease (NAFLD) is the most common and important chronic liver disease all over the world. In the present study, we found that koumine, the main and active ingredient isolated from Gelsemium elegans, has the potential therapeutic effect on NAFLD rats by immunomodulatory activity. Koumine could significantly reduce the level of TG, TC, LDL-C, ALT, and AST in the serum of NAFLD rats and increase the level of HDL-C, reduce the liver index, and improve the adipose-like lesions of liver cells in NAFLD rats. Furthermore, treatment with koumine inhibited the severity of NAFLD. In addition, koumine-treated rats significantly increased the proportion of CD4+/CD8+ T cells and also decreased the percentages of Th1 and Th17 cells and increased Th2 and Treg cells in the liver. Moreover, koumine reduced the production and mRNA expression of proinflammatory cytokines in vivo. This result showed that koumine could effectively modulate different subtypes of helper T cells and prevent NAFLD. The present study revealed the novel immunomodulatory activity of koumine and highlighted the importance to further investigate the effects of koumine on hepatic manifestation of the metabolic syndrome.

Coenzyme Q10 and Degenerative Disorders Affecting Longevity: An Overview

Longevity is determined by a number of factors, including genetic, environmental and lifestyle factors. A major factor affecting longevity is the development of degenerative disorders such as cardiovascular disease, diabetes, kidney disease and liver disease, particularly where these occur as co-morbidities. In this article, we review the potential role of supplementation with coenzyme Q10 (CoQ10) for the prevention or management of these disorders. Thus, randomised controlled clinical trials have shown supplementation with CoQ10 or CoQ10 plus selenium reduces mortality by approximately 50% in patients with cardiovascular disease, or in the normal elderly population, respectively. Similarly, CoQ10 supplementation improves glycaemic control and vascular dysfunction in type II diabetes, improves renal function in patients with chronic kidney disease, and reduces liver inflammation in patients with non-alcoholic fatty liver disease. The beneficial role of supplemental CoQ10 in the above disorders is considered to result from a combination of its roles in cellular energy generation, as an antioxidant and as an anti-inflammatory agent.

The Differential Roles of T Cells in Non-alcoholic Fatty Liver Disease and Obesity

Non-alcoholic fatty liver disease (NAFLD) constitutes a spectrum of disease states characterized by hepatic steatosis and is closely associated to obesity and the metabolic syndrome. In non-alcoholic steatohepatitis (NASH), additionally, inflammatory changes and hepatocellular damage are present, representing a more severe condition, for which the treatment is an unmet medical need. Pathophysiologically, the immune system is one of the main drivers of NAFLD progression and other obesity-related comorbidities, and both the innate and adaptive immune system are involved. T cells form the cellular component of the adaptive immune system and consist of multiple differentially active subsets, i.e., T helper (Th) cells, regulatory T (Treg) cells, and cytotoxic T (Tc) cells, as well as several innate T-cell subsets. This review focuses on the role of these T-cell subsets in the pathogenesis of NAFLD, as well as the association with obesity and type 2 diabetes mellitus, reviewing the available evidence from both animal and human studies. Briefly, Th1, Th2, Th17, and Th22 cells seem to have an attenuating effect on adiposity. Th2, Th22, and Treg cells seem to decrease insulin resistance, whereas Th1, Th17, and Tc cells have an aggravating effect. Concerning NAFLD, both Th22 and Treg cells appear to have an overall tempering effect, whereas Th17 and Tc cells seem to induce more liver damage and fibrosis progression. The evidence regarding the role of the innate T-cell subsets is more controversial and warrants further exploration.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Sarcopenia in patients with non-alcoholic fatty liver disease: is it a clinically significant entity?

Sarcopenia, described as the loss of muscle mass and/or strength, is gaining importance as it can be increasingly related to many chronic diseases. It is also associated with chronic liver disease, and recently it has been more frequently linked to non-alcoholic fatty liver disease (NAFLD) in particular. Both sarcopenia and NAFLD are subject to complex and intermingled pathophysiological processes, of which some are in common. Furthermore, it is presently unclear if sarcopenia directly contributes to NAFLD or vice versa. The mechanisms that are involved may include obesity, insulin resistance, vitamin D deficiency, aging, physical inactivity and certain cytokines. Current clinical evidence is subject to an important heterogeneity in methods and definitions, with additionally also a relative overrepresentation of evidence in Asian ethnicities. Nonetheless, all studies so far point towards the same association between sarcopenia and NAFLD, including an association with NAFLD-severity and NAFLD-related fibrosis. Since the field is in its infancy, clear definitions and further research are needed to aid to improve understanding of the association between NAFLD and sarcopenia. This can eventually lead to additional potential therapeutic interventions. This review attempts to give an overview of the current published literature that links sarcopenia to NAFLD, followed by a discussion of the presumably involved pathophysiological factors, and ends by discussing current unmet needs.

Glucose Lowering Strategies for Cardiac Benefits: Pathophysiological Mechanisms

Recent trials in Type 2 diabetes (T2D) have shown cardiovascular benefits with specific GLP-1 receptor agonists and SGLT2 inhibitors. We discuss the landscape of outcome trials in T2D from a pathophysiology viewpoint, review current knowledge gaps in underlying mechanisms, propose a caloric fuel routing hypothesis, and highlight areas of future research.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The potential role of vascular alterations and subsequent impaired liver blood flow and hepatic hypoxia in the pathophysiology of non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of disease ranging from steatosis to steatohepatitis (NASH) and fibrosis, but the underlying pathophysiological mechanisms remain largely unknown. As there is currently no approved pharmacological therapy and the prevalence of NAFLD keeps increasing, understanding of its pathophysiology is crucial. We hypothesise that vascular alterations in early NAFLD play a role in the progression of the disease by inducing an increased intrahepatic vascular resistance and consequently relative hypoxia in the liver. Evidence of the detrimental effects of hypoxia in NAFLD has already been observed in liver surgery, where the outcomes of steatotic livers after ischaemia-reperfusion are worse than in healthy livers, and in obstructive sleep apnoea, which is an independent risk factor of NAFLD. Moreover, early histological damage in NAFLD is situated in the pericentral zone, which is also the first zone to be affected by a decreased oxygen tension because of the unique hepatic vacsular anatomy that causes the pericentral oxygen tension to be the lowest. Angiogenesis is also a characteristic of NAFLD, driven by hypoxia-induced mechanisms, as demonstrated in both animal models and in humans with NAFLD. Relative hypoxia is most probably induced by impaired blood flow to the liver, caused by increased intrahepatic vascular resistance. An increased intrahepatic vascular resistance early in the development of disease has been convincingly demonstrated in several animal models of NAFLD, whereas an increased portal pressure, a consequence of increased intrahepatic vascular resistance, has been proven in patients with NAFLD. Animal studies demonstrated a decreased intrahepatic effect of vasodilators and an increased reactivity to vasoconstrictors that results in an increased intrahepatic vascular resistance, thus the presence of a functional component. Pharmacological products that target vasoregulation can hence improve the intrahepatic vascular resistance and this might prevent or reverse progression of NAFLD, representing an important therapeutic option to study. Some of the drugs currently under evaluation in clinical trials for NASH have interesting properties related to the hepatic vasculature. Some other interesting drugs have been tested in animal models but further study in patients with NAFLD is warranted. In summary, in this paper we summarise the evidence that leads to the hypothesis that an increased intrahepatic vascular resistance and subsequent parenchymal hypoxia in early NAFLD is an important pathophysiological driving mechanism for the progression of the disease.

Elevated lipolysis in adipose tissue by doxorubicin via PPARα activation associated with hepatic steatosis and insulin resistance

Adipose dysfunction is tightly associated with hepatic insulin resistance and steatosis condition. Doxorubicin would disturb the lipid metabolism both in adipose and liver. Here we projected that doxorubicin would impede lipogenesis and elevated lipolysis in adipose tissue would elevate the circulatory lipid profile and leads to insulin resistance. Further exacerbated lipid profile in circulation would impair the lipid metabolism in hepatic tissue which leads to fatty liver condition and consequently related disease during doxorubicin treatment. Doxorubicin impairs the lipogenesis through PPARγ and augments lipolysis and fatty acid oxidation through ATGL and PPARα in adipose tissue. Increased fatty acid level by adipose tissue in circulation would translocate into the liver and dysregulates AHR, PXR, PPARγ, ATGL and Apo B,which further develop insulin resistance and hepatic steatosis condition. The findings add to the mechanistic role of association between adipose tissue dysfunction and hepatic dysfunction.

Impact of Non-alcoholic Fatty Liver Disease on long-term cardiovascular events and death in Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) and Non-Alcoholic Fatty Liver Disease (NAFLD) both independently increase cardiovascular risk. We hypothesized that NAFLD might increase the incidence of cardiovascular disease and death in COPD patients. The relationship between NAFLD, incident cardiovascular events, and death was assessed in a prospective cohort of COPD patients with 5-year follow-up. Noninvasive algorithms combining biological parameters (FibroMax®) were used to evaluate steatosis, non-alcoholic steatohepatitis (NASH) and liver fibrosis. Univariate and multivariate Cox regression models were used to assess the hazard for composite outcome at the endpoint (death or cardiovascular event) for each liver pathology. In 111 COPD patients, 75% exhibited liver damage with a prevalence of steatosis, NASH and fibrosis of 41%, 37% and 61%, respectively. During 5-year follow-up, 31 experienced at least one cardiovascular event and 7 died. In univariate analysis, patients with liver fibrosis had more cardiovascular events and higher mortality (Hazard ratio [95% CI]: 2.75 [1.26; 6.03]) than those with no fibrosis; this remained significant in multivariate analysis (Hazard ratio [95% CI]: 2.94 [1.18; 7.33]). We also found that steatosis and NASH were not associated with increased cardiovascular events or mortality. To conclude, early assessment of liver damage might participate to improve cardiovascular outcomes in COPD patients.

TRUSS Exacerbates NAFLD Development by Promoting IκBα Degradation in Mice

There is no effective treatment method for nonalcoholic fatty liver disease (NAFLD), the most common liver disease. The exact mechanism underlying the pathogenesis of NAFLD remains to be elucidated. Here, we report that tumor necrosis factor receptor-associated ubiquitous scaffolding and signaling protein (TRUSS) acts as a positive regulator of NAFLD and in a variety of metabolic disorders. TRUSS expression was increased in the human liver specimens with NAFLD or nonalcoholic steatohepatitis, and in the livers of high-fat diet (HFD)-induced and genetically obese mice. Conditional knockout of TRUSS in hepatocytes significantly ameliorated hepatic steatosis, insulin resistance, glucose intolerance, and inflammatory responses in mice after HFD challenge or in spontaneous obese mice with normal chow feeding. All of these HFD-induced pathological phenotypes were exacerbated in mice overexpressing TRUSS in hepatocytes. We show that TRUSS physically interacts with the inhibitor of nuclear factor κB α (IκBα) and promotes the ubiquitination and degradation of IκBα, which leads to aberrant activation of nuclear factor κB (NF-κB). Overexpressing IκBα^S32A/S36A , a phosphorylation-resistant mutant of IκBα, in the hepatocyte-specific TRUSS overexpressing mice almost abolished HFD-induced NAFLD and metabolic disorders. Conclusion: Hepatocyte TRUSS promotes pathological stimuli-induced NAFLD and metabolic disorders, through activation of NF-κB by promoting ubiquitination and degradation of IκBα. Our findings may provide a strategy for the prevention and treatment of NAFLD by targeting TRUSS.

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

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

Among Patients With NAFLD, Treatment of Dyslipidemia Does Not Reduce Cardiovascular Mortality

Dyslipidemia is one of the common risk factors for NAFLD and is associated with cardiovascular (CV) mortality, which is the most common cause of death in NAFLD. Lipid-lowering agents (LLAs) are used to reduce CV events in the general population. Our aim was to assess whether the use of LLAs in patients with NAFLD can reduce the risk of CV mortality. We used the third National Health and Nutrition Examination Survey mortality linked files. Mortality was determined from the National Death Index records through 2011. NAFLD was diagnosed by ultrasound after exclusion of other causes of liver disease. After inclusion and exclusion, the cohort consisted of 2,566 patients with NAFLD (45.8% < 45 years of age, 52.8% male, 75.4% white). Those who were taking LLAs were more likely to be older, non-Hispanic white, and had significantly higher rates of diabetes mellitus (DM), hyperlipidemia, hypertension, metabolic syndrome, and history of CV disease (CVD) (all P< 0.01). In our multivariate analysis, DM was an independent predictor of overall mortality (adjusted hazard ratio [aHR]: 1.79 [95% confidence interval (CI): 1.40-2.30]) and CV mortality (aHR: 1.89 [95% CI: 1.08-3.30]). History of CVD was associated with both overall (aHR: 2.03 [95% CI: 1.57-2.63]) and CV mortality (aHR: 3.69 [95% CI: 2.23-6.08]). In contrast, the use of statins and other LLAs was not associated with reduction in overall (aHR = 0.95 [95% CI: 0.37-2.44] and aHR = 1.43 [95% CI: 0.99-2.07]) and CV mortality (aHR = 1.20 [95% CI: 0.26-5.54] and aHR = 1.63 [95% CI: 0.70-3.76]). Conclusion: The use of statins and other LLAs did not reduce the increased risk of overall or CV mortality in NAFLD.

Switching obese mothers to a healthy diet improves fetal hypoxemia, hepatic metabolites, and lipotoxicity in non-human primates

Objective

Non-alcoholic fatty liver disease (NAFLD) risk begins in utero in offspring of obese mothers. A critical unmet need in this field is to understand the pathways and biomarkers underlying fetal hepatic lipotoxicity and whether maternal dietary intervention during pregnancy is an effective countermeasure.

Methods

We utilized a well-established non-human primate model of chronic, maternal, Western-style diet induced obesity (OB-WSD) compared with mothers on a healthy control diet (CON) or a subset of OB-WSD mothers switched to the CON diet (diet reversal; OB-DR) prior to and for the duration of the next pregnancy. Fetuses were studied in the early 3rd trimester.

Results

Fetuses from OB-WSD mothers had higher circulating triglycerides (TGs) and lower arterial oxygenation suggesting hypoxemia, compared with fetuses from CON and OB-DR mothers. Hepatic TG content, oxidative stress (TBARs), and de novo lipogenic genes were increased in fetuses from OB-WSD compared with CON mothers. Fetuses from OB-DR mothers had lower lipogenic gene expression and TBARs yet persistently higher TGs. Metabolomic profiling of fetal liver and serum (umbilical artery) revealed distinct separation of CON and OB-WSD groups, and an intermediate phenotype in fetuses from OB-DR mothers. Pathway analysis identified decreased tricarboxylic acid cycle intermediates, increased amino acid (AA) metabolism and byproducts, and increased gluconeogenesis, suggesting an increased reliance on AA metabolism to meet energy needs in the liver of fetuses from OB-WSD mothers. Components in collagen synthesis, including serum protein 5-hydroxylysine and hepatic lysine and proline, were positively correlated with hepatic TGs and TBARs, suggesting early signs of fibrosis in livers from the OB-WSD group. Importantly, hepatic gluconeogenic and arginine related intermediates and serum levels of lactate, pyruvate, several AAs, and nucleotide intermediates were normalized in the OB-DR group. However, hepatic levels of CDP-choline and total ceramide levels remained high in fetuses from OB-DR mothers.

Conclusions

Our data provide new metabolic evidence that, in addition to fetal hepatic steatosis, maternal WSD creates fetal hypoxemia and increases utilization of AAs for energy production and early activation of gluconeogenic pathways in the fetal liver. When combined with hyperlipidemia and limited antioxidant activity, the fetus suffers from hepatic oxidative stress and altered intracellular metabolism which can be improved with maternal diet intervention. Our data reinforce the concept that multiple “first hits” occur in the fetus prior to development of obesity and demonstrate new biomarkers with potential clinical implications for monitoring NAFLD risk in offspring.

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Maternal WSD increases fetal hypoxemia and utilization of AAs for gluconeogenesis.

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Maternal WSD increases fetal oxidative stress and precursors to liver fibrosis.

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Carnosine and l-proline uniquely correlated with fetal TG and oxidative stress.

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Fetal TGs were correlated with fetal arterial oxygen saturation.

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Diet reversal in obese WSD mothers prevents fetal hypoxemia and oxidative stress.

Therapeutic inhibition of spleen tyrosine kinase in inflammatory macrophages using PLGA nanoparticles for the treatment of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is the leading cause of cirrhosis worldwide and the most rapidly growing indication for liver transplantation. Macrophages are the important cellular component in the inflammatory milieu in NASH. Inflammatory and pro-fibrotic mediators produced by macrophages causes significant tissue injury in many inflammatory diseases. Therefore, inhibition of the inflammatory macrophages would be a promising approach to attenuate NASH. In this study, we studied the implication of SYK pathway in NASH, and investigated PLGA nanoparticles-based delivery of SYK pathway inhibitor as an effective and promising therapeutic approach for the treatment of NASH. We found positive correlation between SYK expression with the pathogenesis of NASH and alcoholic hepatitis in patients. Importantly, SYK expression was significantly induced in M1-differentiated inflammatory macrophages. To inhibit SYK pathway specifically, we used a small-molecule inhibitor R406 that blocks Fc-receptor signaling pathway and reduces immune complex-mediated inflammation. R406 dose-dependently inhibited nitric-oxide release and M1-specific markers in M1-differentiated macrophages. Thereafter, we synthesized PLGA nanoparticles to deliver R406 to increase the drug pharmacokinetics for the efficient treatment of NASH. We investigated the therapeutic efficacy of R406-PLGA in-vitro in differentiated macrophages, and in-vivo in Methionine-Choline-deficient (MCD)-diet induced NASH mouse model. R406-PLGA inhibited M1-specific differentiation markers in RAW and bone-marrow-derived macrophages. In-vivo, R406 and more strongly R406-PLGA ameliorated fibrosis, inflammation and steatosis in mice. R406 and more significantly R406-PLGA reduced ALT, AST, cholesterol and triglyceride plasma levels. These results suggest that delivery of SYK inhibitor using PLGA nanoparticles can be a potential therapeutic approach for the treatment of Non-alcoholic steatohepatitis.

A systematic review of the present and future of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the Western world. Ongoing research has furthered our understanding of NAFLD, the nature of progression of this disease, and its impact on morbidity and mortality. An active form of NAFLD is non-alcoholic steatohepatitis (NASH); it is the most severe subtype, without any current recommended therapies, according to the European Medicines Agency. The development of new therapies presents challenges, notably due to the slow progression of NASH and the clinically relevant endpoints.

Correlating new data with effective treatment regimens is an emerging challenge, which will increase our understanding of the factors affecting the NAFLD course. This can enable more appropriate non-invasive prognostic assessments, which can focus on specifically at-risk NAFLD populations for tailored individual treatment. This review article aims to highlight the current developments in the field of NAFLD: pathogenesis, epidemiology, diagnosis, clinical features, and available treatment, including novel targets and therapies.

The impact of non-alcoholic fatty liver disease and metabolic syndrome on the progression of coronary artery calcification

It is unclear whether non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for cardiovascular disease. We examined the independent impact of NAFLD on the progression of the coronary artery calcification (CAC) score, a well-known marker of atherosclerosis progression. We examined 1,173 asymptomatic participants who underwent repeated CAC score measurement during routine health examinations. The subjects were categorised into four groups based on the presence (+) or absence (−) of NAFLD and metabolic syndrome (MetS). The progression of CAC score was defined as either incident CAC in a CAC-free population at baseline or an increase of ≥2.5 units between the baseline and the final square roots of the CAC scores of participants with detectable CAC at baseline. CAC progression was seen in 18.6% (98/526), 28.3% (77/272), 29.1% (30/103) and 32.0% (87/272) of the subjects with NAFLD(−)/MetS(−), NAFLD(+)/MetS(−), NAFLD(−)/MetS(+) and NAFLD(+)/MetS(+), respectively. The subjects with NAFLD(+)/MetS(+) and NAFLD(+)/MetS(−) had a significantly higher risk of CAC progression than those with NAFLD(−)/MetS(−) (multivariate-adjusted odds ratio [OR]: 1.76; 95% confidence interval [CI]: 1.18–2.62 and multivariate-adjusted OR: 1.53, 95% CI: 1.05–2.23, respectively). NAFLD is an independent risk factor for CAC progression, irrespective of the presence of MetS.

Impaired HDL cholesterol efflux capacity in patients with non-alcoholic fatty liver disease is associated with subclinical atherosclerosis

Non-alcoholic fatty liver disease (NAFLD) is associated with a substantial increased risk of atherosclerotic cardiovascular disease (ASCVD), which is partly related to dyslipidemia and low HDL-C level. The cardioprotective activity of HDL in the body is closely connected to its role in promoting cholesterol efflux, which is determined by cholesterol efflux capacity (CEC). Hitherto, the role of HDL, as defined by CEC has not been assessed in NAFLD patients. In this research study, we present the results of a study of cAMP-treated J774 CEC and THP-1 macrophage CEC in ApoB-depleted plasma of 55 newly diagnosed NAFLD patients and 30 controls. Circulating levels of ApoA-I, ApoB, preβ-HDL, plasma activity of CETP, PLTP, LCAT and carotid intima-media thickness (cIMT) were estimated. cAMP-treated J774 and THP-1 macrophage CEC were found to be significantly lower in NAFLD patients compared to controls (P < 0.001 and P = 0.003, respectively). In addition, it was discovered that both ApoA-I and preβ1-HDL were significantly lower in NAFLD patients (P < 0.001). Furthermore, cAMP-treated J774 CEC showed independent negative correlation with cIMT, as well as the presence of atherosclerotic plaque in NAFLD patients. In conclusion, our findings showed that HDL CEC was suppressed in NAFLD patients, and impaired cAMP-treated J774 CEC was an independent risk factor for subclinical atherosclerosis in NAFLD patients, suggesting that impaired HDL functions as an independent risk factor for atherosclerosis in NAFLD.

Association of Nonalcoholic Fatty Liver Disease With Osteoporotic Fractures: A Cross-Sectional Retrospective Study of Chinese Individuals

Objective: Nonalcoholic fatty liver disease (NAFLD) is related to several inflammatory or metabolic diseases. However, findings of previous studies investigating the association between NAFLD and BMD are inconsistent. Only one study reported a potential association between NAFLD and osteoporotic fracture. This study investigated whether NAFLD in older participants (>55 years) was associated with osteoporotic fracture risk. Materials and Methods: This cross-sectional, observational study included 2,695 participants (35.7% men, 614 cases of NAFLD, and 383 fractures). Standardized questionnaires, laboratory tests, and physical and ultrasonic examinations were completed. Results: After adjusting for various factors including serum triglycerides (TG), high-density cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), multivariate logistic regression models revealed a marginal association between NAFLD and osteoporotic fracture risk in men (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.06-3.27; P = 0.030) but no association in women (OR, 1.05; 95% CI, 0.74-1.48; P = 0.800). Further stratified analyses showed a significant association between NAFLD and osteoporotic fracture risk in men without high TG, low HDL-C, and high LDL-C. Conclusions: There was a significant association between NAFLD and osteoporotic fracture risk in older Chinese men, particularly men without dyslipidemia.

Quantification of Liver Fat Content With Unenhanced MDCT: Phantom and Clinical Correlation With MRI Proton Density Fat Fraction

OBJECTIVE

The purpose of this study was to evaluate the relation between unenhanced CT liver attenuation values and MRI-derived proton density fat fraction (PDFF) for estimation of liver fat content at CT.

MATERIALS AND METHODS

A CT-MRI phantom was constructed and imaged containing 12 vials with lipid fractions ranging from 0% to 100%. For the retrospective clinical arm, 221 patients (120 men, 101 women; mean age, 54 years) underwent both unenhanced CT and chemical shift-encoded MRI of the liver between 2007 and 2017. Among these patients, 92 had more than one 120-kV CT scan for comparison. CT attenuation and MRI PDFF were derived with coregistered ROI measurements in the right hepatic lobe. The 120-kV subgroup of CT examinations performed within 1 month of MRI PDFF examinations (n = 72) served as the primary cohort for linear correlation. The effects of different tube voltage settings, time intervals between CT and MRI, and iron overload were assessed. Linear least squares regression analysis was performed.

RESULTS

Phantom results showed excellent linear fit between CT attenuation and MRI PDFF (r² = 0.986). In patients, 120-kV CT performed within 1 month of MRI PDFF exhibited strong linear correlation (r² = 0.828) that closely matched the phantom data, yielding the following clinical CT-MRI conversion formula: MRI PDFF (%) = -0.58 × CT attenuation (HU) + 38.2. Correlation worsened for CT-to-MRI intervals longer than 1 month (r² = 0.565), and this specific relationship did not apply as well to non-120-kV settings (r² = 0.554). For patients with multiple scans, correlation progressively worsened over time. CT-based liver fat content was underestimated in several patients with iron overload.

CONCLUSION

The linear correlation between unenhanced CT attenuation and MRI PDFF allows quantification of liver fat content by means of unenhanced CT in clinical practice. As expected, correlation worsened with increasing CT-MRI time interval, variable tube voltage settings, and iron overload.

Vitamin D supplementation for the treatment of non-alcoholic fatty liver disease: A randomized double blind placebo controlled trial

BACKGROUND

Low serum vitamin D has been associated with metabolic syndrome and Non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the impact of vitamin D supplementation in treatment of patients with NAFLD.

METHODS

In a double blind, randomized, placebo controlled trial patients with NAFLD were randomized to receive one weekly pearl of placebo, 50,000 U vitamin D3 (cholecalciferol) pearl per week and 0.25 mg calcitriol (1,25 dihydroxycholecalciferol) pearl per day for 3 months.

RESULTS

106 NAFLD patients were randomized to receive calcitriol, vitamin D3 and placebo pearls for 12 weeks and data for 91 patients were analyzed. After 12 weeks of treatment, serum alkaline phosphatase levels was significantly decreased from baseline levels in vitamin D and calcitriol treated groups (P < 0.05). Serum and gamma glutamyl transferase (GGT) level was also significantly decreased compared to the baseline levels after 12 weeks of treatment with vitamin D. There was no statistically significant difference between placebo, calcitriol, vitamin D groups in terms of serum aminotransferase, alkaline phosphatase, serum GGT and lipid profile (P > 0.05).

CONCLUSION

While significant reduction of serum alkaline phosphatase and GGT were seen with vitamin D and calcitriol supplementation from baseline levels, no beneficial effects was seen when comparing vitamin D, calcitriol and placebo groups at the end of trial.

Association between abdominal adiposity and subclinical measures of left-ventricular remodeling in diabetics, prediabetics and normal controls without history of cardiovascular disease as measured by magnetic resonance imaging: results from the KORA-FF4 Study

OBJECTIVES

Local, abdominal fat depots may be related to alterations in cardiac function and morphology due to a metabolic linkage. Thus, we aimed to determine their association with subtle cardiac changes and the potential interaction with hyperglycemic metabolic states.

METHODS

Subjects from the general population and without history of cardiovascular disease were drawn from the Cooperative Health Research in the Region of Augsburg FF4 cohort and underwent 3 T cardiac and body MRI. Measures of abdominal adiposity such as hepatic proton-density fat fraction [PDFF_hepatic], subcutaneous (SAT) and visceral abdominal fat (VAT) as well as established cardiac left-ventricular (LV) measures including LV remodeling index (LVCI) were derived. Associations were determined using linear regression analysis based on standard deviation normalized predictors.

RESULTS

Among a total of 374 subjects (56.2 ± 9.1 years, 58% males), 49 subjects had diabetes, 99 subjects had prediabetes and 226 represented normal controls. Only subtle cardiac alterations were observed (e.g. LVCI: 1.13 ± 0.30). While SAT was not associated, increasing VAT and increasing PDFF_hepatic were independently associated with increasing LVCI (β = 0.11 and 0.06, respectively), decreasing LV end-diastolic volume (β = - 6.70 and 3.23, respectively), and decreasing LV stroke volume (β = - 3.91 and - 2.20, respectively). Hyperglycemic state did not modify the associations between VAT or PDFF and LV measures (interaction term: all p ≥ 0.29).

CONCLUSION

In a healthy population, VAT but also PDFF_hepatic were associated with subclinical measures of LV remodeling without evidence for a modifying effect of hyperglycemic state.

High red and processed meat consumption is associated with non-alcoholic fatty liver disease and insulin resistance

BACKGROUND & AIMS

High red and processed meat consumption is related to type 2 diabetes. In addition, cooking meat at high temperatures for a long duration forms heterocyclic amines (HCAs), which are related to oxidative stress. However, the association between meat consumption and non-alcoholic fatty liver disease (NAFLD) is yet to be thoroughly tested. Therefore, we aimed to test the association of meat type and cooking method with NAFLD and insulin resistance (IR).

METHODS

This was a cross-sectional study in individuals who were 40-70 years old and underwent screening colonoscopy between 2013 and 2015 in a single center in Israel. NAFLD and IR were evaluated by ultrasonography and homeostasis model assessment. Meat type and cooking method were measured by a food frequency questionnaire (FFQ) and a detailed meat questionnaire. Unhealthy cooking methods were considered as frying and grilling to a level of well done and very well done. Dietary HCA intake was calculated.

RESULTS

A total of 789 individuals had a valid FFQ and 357 had a valid meat questionnaire. High consumption of total meat (portions/day above the median) (odds ratio [OR] 1.49; 95% CI 1.05-2.13; p = 0.028; OR 1.63; 1.12-2.37; p = 0.011), red and/or processed meat (OR1.47; 95% CI 1.04-2.09; p = 0.031; OR1.55; 1.07-2.23; p = 0.020) was independently associated with higher odds of NAFLD and IR, respectively, when adjusted for: body mass index, physical activity, smoking, alcohol, energy, saturated fat and cholesterol intake. High intake of meat cooked using unhealthy methods (OR1.92; 95% CI 1.12-3.30; p = 0.018) and HCAs (OR2.22; 95% CI 1.28-3.86; p = 0.005) were independently associated with higher odds of IR.

CONCLUSION

High consumption of red and/or processed meat is associated with both NAFLD and IR. High HCA intake is associated with IR. If confirmed in prospective studies, limiting the consumption of unhealthy meat types and improving preparation methods may be considered as part of NAFLD lifestyle treatment.

LAY SUMMARY

High red and processed meat consumption is related to several diseases. In addition, cooking meat at high temperatures for a long duration forms heterocyclic amines, which have harmful health effects. Non-alcoholic fatty liver disease is a significant public health burden and its formation is strongly related to insulin resistance. In this study, both were found to be more frequent in people who consume relatively high quantities of red and processed meat. In addition, a high intake of heterocyclic amines was associated with insulin resistance.

Resolution of fatty liver and weight loss: Independent associations with changes in serum lipids and apolipoproteins

BACKGROUND AND AIMS

It is uncertain whether resolution of fatty liver can improve cardiovascular disease risk factors, independently of changes in body mass index (BMI). Our aim was to test whether resolution of fatty liver is associated with improvements in components of the lipid profile, independently of changes in BMI, and to quantify and compare the magnitude of benefit of resolution of liver fat, and decreases in BMI on the lipid profile.

METHODS

36,195 subjects with fatty liver were studied. Persistence/resolution of fatty liver was determined by ultrasound at follow up (mean = 4.93 years). Total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and apolipoproteins were measured at baseline and follow up. Regression modelling was undertaken to test the independence of associations between change in fatty liver status or change in BMI, with any change in lipid profile concentrations between baseline and follow up.

RESULTS

Mean (SD) age was 36.3 ± 6.6 and 39.8 ± 8.7 years (men and women, respectively). Resolution of fatty liver occurred in 7,086, and persisted in 29,109 subjects. Mean ± SD weight change was -3.2 ± 4.3 (∼1 kg/m2 decrease in BMI) with resolution of, and +0.5 ± 3.5 kg with persistence of fatty liver, respectively. Both resolution of fatty liver and decrease in BMI were independently associated with improvements in all components of the lipid profile and there was a similar magnitude of benefit associated with resolution of fatty liver, or 1 kg/m2 decrease in BMI.

CONCLUSIONS

Resolution of fatty liver improves the lipid profile, independently of weight loss.

"Trans-nonachlor increases extracellular free fatty acid accumulation and de novo lipogenesis to produce hepatic steatosis in McArdle-RH7777 cells"

Recent studies suggest there may be an environmental exposure component to the development and progression of non-alcoholic fatty liver disease (NAFLD) involving the organochlorine (OC) pesticides or their metabolites. However, the roles of OC compounds in the development of NAFLD has not been fully elucidated. Therefore, the current study was designed to determine if exposure to trans-nonachlor, a prevalent OC compound, could promote hepatocyte lipid accumulation and determine potential pro-steatotic mechanisms. McArdle-RH7777 (McA) hepatoma cells were incubated with trans-nonachlor for 24 h then neutral lipid accumulation was determined by Oil Red O staining. Exposure to trans-nonachlor produced a concentration dependent increase in neutral lipid accumulation. Trans-nonachlor also increased extracellular free fatty acid-induced neutral lipid accumulation which appears to be due at least in part to increased free fatty acid accumulation as evident by increased accumulation of Bodipy labeled dodecanoic acid. Additionally, ¹⁴C-acetate incorporation into total cellular lipids was increased by trans-nonachlor implicating increased de novo lipogenesis (DNL) as a potential mediator of trans-nonachlor-induced neutral lipid accumulation. Taken together, the present data indicate exposure to trans-nonachlor has a direct, pro-steatotic effect on hepatocytes to increase lipid accumulation through the combinatorial actions of extracellular free fatty acid accumulation and increased DNL.

Foxo3a-dependent Bim transcription protects mice from a high fat diet via inhibition of activation of the NLRP3 inflammasome by facilitating autophagy flux in Kupffer cells

Background

The role of Foxo3a in the regulation of autophagy flux and activation of the NLRP3 inflammasome in KCs suffering from HFD conditions is unknown.

Results

Up-regulation of Foxo3a restored autophagy flux and dampened the activation of the NLRP3 inflammasome in KCs stimulated with PA and LPS. In contrast, down-regulation of Foxo3a increased blockage of autophagy flux and promoted NLRP3 inflammasome activation. Additionally, mRNA levels of Bim were significantly changed with the alteration of Foxo3a in KCs under PA and LPS stimulation among foxo3a targeted genes. Overexpression of Bim restored autophagy influx and attenuated NLRP3 inflammasome pathway activation. In addition, autophagy formation was restored, and activation of NLRP3 inflammasome was inhibited in KCs isolated from mice treated with Iturin A and fed with a HFD.

Materials and methods

Autophagy flux in KCs and activation levels of NLRP3 inflammasome were evaluated after altering the expression of Foxo3a in KCs before stimulation with PA and LPS. Additionally, various target genes of Foxo3a were measured in KCs pretreated with an agonist (Iturin A) or inhibitor (SC97) of Foxo3a after KCs stimulation with PA and LPS in order to hunt for targets of Foxo3a. Activation levels of NLRP3 inflammasome in isolated KCs, as well as autophagy flux, were measured after mice were treated with Iturin A and fed with a HFD for 16 weeks.

Conclusions

Foxo3a restores autophagy flux and attenuates the activation of the NLRP3 inflammasome by promoting the transcription of Bim, suggesting a potential therapeutic target in NAFLD and other obesity-related diseases.

The characteristics of residents with unawareness of hepatitis C virus infection in community

BACKGROUND

Control of hepatitis C virus infection (HCV) is an increasingly important issue. Enhancing screening coverage is necessary to discover more HCV infected subjects in community. However, a substantial population is unaware of HCV infection that needs more attention.

AIM

The aims of this study were to evaluate the status of HCV infected residents in remote villages, to compare characteristics between already known and unaware HCV infection subjects, and to analyze the disease insights.

PATIENTS AND METHODS

Screening intervention for liver diseases was conducted in remote villages of Tainan City of southern Taiwan from August 2014 to July 2016. Items of screening examinations included questionnaire, blood sampling for liver tests and viral hepatitis markers (hepatitis B surface antigen and anti-HCV antibody), abdominal sonography survey, and liver stiffness measurement by transient elastography. Quantitation of HCV RNA was measured for residents with positive anti-HCV antibody.

RESULTS

A total of 194 (13.5%) out of 1439 participants showed positive for anti-HCV antibody. HCV viremia was detected in 119 (61.3%) residents. Previously unaware HCV infection by questionnaire record was present in 68 (35.1%) of ant-HCV positive residents. By multivariate logistic analysis, unaware HCV infected residents exhibited significantly mild liver fibrosis (OR 0.876, 95% CI 0.782~0.981, p = 0.022), more prevalent of heart diseases (OR 6.082, 95% CI 1.963~18.839, p = 0.002), and less cluster of family history of liver diseases (OR 0.291, 95% CI 0.113~0.750, p = 0.011) when comparing with already known HCV infected residents. Among the 126 already know HCV infected residents, only 59 (46.8%) received antiviral treatment or regular follow-up. No concept or no willing to receive medical care was observed in 44 (34.9%) residents.

CONCLUSION

In HCV endemic villages of Taiwan, residents with unaware HCV infection comprised about one third of HCV infected residents and exhibited obscure characteristics to identify. Less than half of already known HCV infected residents received adequate medical care. To eliminate HCV infection, vigorous efforts on enhancing screening coverage, educating update knowledge of liver diseases, and linking to medical care are urgently needed.

The Potential and Action Mechanism of Polyphenols in the Treatment of Liver Diseases

Liver disease, involving a wide range of liver pathologies from fatty liver, hepatitis, and fibrosis to cirrhosis and hepatocellular carcinoma, is a serious health problem worldwide. In recent years, many natural foods and herbs with abundant phytochemicals have been proposed as health supplementation for patients with hepatic disorders. As an important category of phytochemicals, natural polyphenols have attracted increasing attention as potential agents for the prevention and treatment of liver diseases. The striking capacities in remitting oxidative stress, lipid metabolism, insulin resistance, and inflammation put polyphenols in the spotlight for the therapies of liver diseases. It has been reported that many polyphenols from a wide range of foods and herbs exert therapeutic effects on liver injuries via complicated mechanisms. Therefore, it is necessary to have a systematical review to sort out current researches to help better understand the potentials of polyphenols in liver diseases. In this review, we aim to summarize and update the existing evidence of natural polyphenols in the treatment of various liver diseases by in vitro, in vivo, and clinical studies, while special attention is paid to the action mechanisms.

Targeting the gut microbiota with inulin-type fructans: preclinical demonstration of a novel approach in the management of endothelial dysfunction

OBJECTIVE

To investigate the beneficial role of prebiotics on endothelial dysfunction, an early key marker of cardiovascular diseases, in an original mouse model linking steatosis and endothelial dysfunction.

DESIGN

We examined the contribution of the gut microbiota to vascular dysfunction observed in apolipoprotein E knockout (Apoe^-/-) mice fed an n-3 polyunsaturated fatty acid (PUFA)-depleted diet for 12 weeks with or without inulin-type fructans (ITFs) supplementation for the last 15 days. Mesenteric and carotid arteries were isolated to evaluate endothelium-dependent relaxation ex vivo. Caecal microbiota composition (Illumina Sequencing of the 16S rRNA gene) and key pathways/mediators involved in the control of vascular function, including bile acid (BA) profiling, gut and liver key gene expression, nitric oxide and gut hormones production were also assessed.

RESULTS

ITF supplementation totally reverses endothelial dysfunction in mesenteric and carotid arteries of n-3 PUFA-depleted Apoe^-/- mice via activation of the nitric oxide (NO) synthase/NO pathway. Gut microbiota changes induced by prebiotic treatment consist in increased NO-producing bacteria, replenishment of abundance in Akkermansia and decreased abundance in bacterial taxa involved in secondary BA synthesis. Changes in gut and liver gene expression also occur upon ITFs suggesting increased glucagon-like peptide 1 production and BA turnover as drivers of endothelium function preservation.

CONCLUSIONS

We demonstrate for the first time that ITF improve endothelial dysfunction, implicating a short-term adaptation of both gut microbiota and key gut peptides. If confirmed in humans, prebiotics could be proposed as a novel approach in the prevention of metabolic disorders-related cardiovascular diseases.

Reversal of metabolic disorders by pharmacological activation of bile acid receptors TGR5 and FXR

Objectives

Activation of the bile acid (BA) receptors farnesoid X receptor (FXR) or G protein-coupled bile acid receptor (GPBAR1; TGR5) improves metabolic homeostasis. In this study, we aim to determine the impact of pharmacological activation of bile acid receptors by INT-767 on reversal of diet-induced metabolic disorders, and the relative contribution of FXR vs. TGR5 to INT-767's effects on metabolic parameters.

Methods

Wild-type (WT), Tgr5^−/−, Fxr^−/−, Apoe^−/− and Shp^−/− mice were used to investigate whether and how BA receptor activation by INT-767, a semisynthetic agonist for both FXR and TGR5, could reverse diet-induced metabolic disorders.

Results

INT-767 reversed HFD-induced obesity dependent on activation of both TGR5 and FXR and also reversed the development of atherosclerosis and non-alcoholic fatty liver disease (NAFLD). Mechanistically, INT-767 improved hypercholesterolemia by activation of FXR and induced thermogenic genes via activation of TGR5 and/or FXR. Furthermore, INT-767 inhibited several lipogenic genes and de novo lipogenesis in the liver via activation of FXR. We identified peroxisome proliferation-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (CEBPα) as novel FXR-regulated genes. FXR inhibited PPARγ expression by inducing small heterodimer partner (SHP) whereas the inhibition of CEBPα by FXR was SHP-independent.

Conclusions

BA receptor activation can reverse obesity, NAFLD, and atherosclerosis by specific activation of FXR or TGR5. Our data suggest that, compared to activation of FXR or TGR5 only, dual activation of both FXR and TGR5 is a more attractive strategy for treatment of common metabolic disorders.

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Bile acid receptor activation improves lipid homeostasis primarily via activation of FXR.

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Bile acid receptor activation reverses DIO and induces energy expenditure.

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Bile acid receptor activation reverses diet-induced NAFLD and atherosclerosis.

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Bile acid receptor activation inhibits hepatic lipogenesis via activation of FXR.

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Activation of FXR inhibits PPARγ dependent on SHP and CEBPα independent of SHP.

Development of chronic kidney disease in patients with non-alcoholic fatty liver disease: A cohort study

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) has been associated with chronic kidney disease (CKD), but cohort studies are limited. We investigated the longitudinal association of NAFLD and its severity with the development of CKD.

METHODS

We performed a retrospective cohort study of 41,430 adult men and women (average age, 48.9y) without CKD at baseline who underwent repeated health check-up examinations from January 1, 2003, through December 31, 2013. NAFLD status was assessed by ultrasonography, and NAFLD severity was assessed by the NAFLD fibrosis score (NFS).

RESULTS

The outcome was an incident CKD, defined as an estimated glomerular filtration rate less than 60ml/min/1.73m². During 200,790 person-years of follow-up (median follow-up of 4.15years), we identified 691 incident CKD cases. The multivariable-adjusted hazard ratio for CKD comparing participants with and without NAFLD was 1.22 (95% confidence interval [CI] 1.04-1.43). The risk of CKD increased progressively with increased NAFLD severity. The multivariable-adjusted hazard ratios for CKD comparing participants with NFS <-1.455 and those with NFS ≥-1.455 to participants without NAFLD were 1.09 (95% CI 0.91-1.32) and 1.58 (95% CI 1.30-1.92), respectively. The association was consistent across clinically relevant subgroups.

CONCLUSION

In a large cohort of adult men and women without CKD, NAFLD was associated with an increased risk of CKD development. NAFLD may adversely affect renal function and patients may need to be carefully monitored for an increased risk of CKD.

LAY SUMMARY

The presence of fatty liver is associated with the future decline of renal function. Thus, fatty liver patients need to be monitored regularly for renal function.

Quantitative assessment of liver fibrosis reveals a nonlinear association with fibrosis stage in nonalcoholic fatty liver disease

Accurate staging of liver fibrosis is crucial to guide therapeutic decisions for patients with nonalcoholic fatty liver disease (NAFLD). Digital image analysis has emerged as a promising tool for quantitative assessment of fibrosis in chronic liver diseases. We sought to determine the relationship of histologic fibrosis stage with fiber amounts quantified in liver biopsy specimens for the better understanding of NAFLD progression. We measured area ratios of collagen and elastin fibers in Elastica van Gieson-stained biopsy tissues from 289 patients with NAFLD from four hospitals using an automated computational method and examined their correlations with Brunt's fibrosis stage. As a secondary analysis, we performed multivariable logistic regression analysis to assess the associations of the combined area ratios of collagen and elastin with noninvasive fibrosis markers. The combined fiber area ratios correlated strongly with Brunt's stage (Spearman correlation coefficient, 0.78; P < 0.0001), but this relationship was nonlinear (P = 0.007) with striking differences between stage 4 (median area ratios, 12.3%) and stages 0-3 (2.1%, 2.8%, 4.3%, and 4.8%, respectively). Elastin accumulation was common in areas of thick bridging fibrosis and thickened venous walls but not in areas of perisinusoidal fibrosis. The highest tertile of the combined fiber area ratios was associated with the fibrosis-4 index and serum type IV collagen 7s domain (7s collagen) levels, whereas the upper two tertiles of the fiber amounts significantly associated with body mass index, aspartate aminotransferase, and 7s collagen in the multivariable analysis. Conclusion: Quantitative fibrosis assessment reveals a nonlinear relationship between fibrosis stage and fiber amount, with a marked difference between stage 4 and stage 3 and much smaller differences among stages 0-3, suggesting a heterogeneity in disease severity within NAFLD-related cirrhosis. (Hepatology Communications 2018;2:58-68).

PNPLA3 variant and portal/periportal histological pattern in patients with biopsy-proven non-alcoholic fatty liver disease: a possible role for oxidative stress

Pathogenesis of non-alcoholic fatty liver disease (NAFLD) is influenced by predisposing genetic variations, dysmetabolism, systemic oxidative stress, and local cellular and molecular cross-talks. Patatin-like phospholipase domain containing 3 (PNPLA3) gene I148M variant is a known determinant of NAFLD. Aims were to evaluate whether PNPLA3 I148M variant was associated with a specific histological pattern, hepatic stem/progenitor cell (HpSC) niche activation and serum oxidative stress markers. Liver biopsies were obtained from 54 NAFLD patients. The activation of HpSC compartment was evaluated by the extension of ductular reaction (DR); hepatic stellate cells, myofibroblasts (MFs), and macrophages were evaluated by immunohistochemistry. Systemic oxidative stress was assessed measuring serum levels of soluble NOX2-derived peptide (sNOX2-dp) and 8-isoprostaglandin F2α (8-iso-PGF2α). PNPLA3 carriers showed higher steatosis, portal inflammation and HpSC niche activation compared to wild-type patients. DR was correlated with NAFLD activity score (NAS) and fibrosis score. Serum 8-iso-PGF2α were significantly higher in I148M carriers compared to non-carriers and were correlated with DR and portal inflammation. sNox2-dp was correlated with NAS and with HpSC niche activation. In conclusion, NAFLD patients carrying PNPLA3 I148M are characterized by a prominent activation of HpSC niche which is associated with a more aggressive histological pattern (portal fibrogenesis) and increased oxidative stress.

Use of Statins in Patients with Chronic Liver Disease and Cirrhosis: Current Views and Prospects

PURPOSE OF REVIEW

The purpose of this study is to analyze the current evidence regarding the use of statins in patients with chronic liver disease and cirrhosis.

RECENT FINDINGS

Chronic liver disease (CLD), cirrhosis, and its complications, including hepatocellular carcinoma (HCC), are significant public health problems. The use of statins in patients with CLD has been a matter of concern, and physicians are often reluctant to its prescription in these patients. This mainly relates to the potential occurrence of drug-induced liver injury. However, newer evidence from pre-clinical and clinical research has shown that statins are drugs with a potentially beneficial impact on the natural history of cirrhosis, on portal hypertension, and in HCC prevention. In this review, we summarize current evidence regarding the influence of statins in endothelial dysfunction in CLD, their ability to modulate hepatic fibrogenesis, and their vasoprotective effects in portal hypertension; we also focus on existing data about the impact of statins in cirrhosis development, progression, and complications and critically assess the current concerns about its use in patients with CLD.

Animal Models of Nonalcoholic Fatty Liver Disease-A Starter's Guide

Nonalcoholic fatty liver disease (NAFLD) constitutes a major health concern with the increasing incidence of obesity and diabetes in many Western countries, reaching a prevalence of up to 30% in the general population. Animal models have played a vital role in elucidating the pathophysiological mechanisms of NAFLD and continue to do so. A myriad of different models exists, each with its advantages and disadvantages. This review presents a brief overview of these models with a particular focus on the basic mechanisms and physical, biochemical and histological phenotype. Both nutritional and chemically induced, as well as genetic models are examined, including models combining different approaches.

Isocaloric Dietary Changes and Non-Alcoholic Fatty Liver Disease in High Cardiometabolic Risk Individuals

Non-alcoholic fatty liver disease (NAFLD) incorporates an extensive spectrum of histologic liver abnormalities, varying from simple triglyceride accumulation in hepatocytes non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH), and it is the most frequent chronic liver disease in the industrialized world. Beyond liver related complications such as cirrhosis and hepatocellular carcinoma, NAFLD is also an emerging risk factor for type 2 diabetes and cardiovascular disease. Currently, lifestyle intervention including strategies to reduce body weight and to increase regular physical activity represents the mainstay of NAFLD management. Total caloric intake plays a very important role in both the development and the treatment of NAFLD; however, apart from the caloric restriction alone, modifying the quality of the diet and modulating either the macro- or micronutrient composition can also markedly affect the clinical evolution of NAFLD, offering a more realistic and feasible treatment alternative. The aim of the present review is to summarize currently available evidence from randomized controlled trials on the effects of different nutrients including carbohydrates, lipids, protein and other dietary components, in isocaloric conditions, on NAFLD in people at high cardiometabolic risk. We also describe the plausible mechanisms by which different dietary components could modulate liver fat content.

Fructose: A Dietary Sugar in Crosstalk with Microbiota Contributing to the Development and Progression of Non-Alcoholic Liver Disease

Fructose is one of the key dietary catalysts in the development of non-alcoholic fatty liver disease (NAFLD). NAFLD comprises a complex disease spectrum, including steatosis (fatty liver), non-alcoholic steatohepatitis, hepatocyte injury, inflammation, and fibrosis. It is also the hepatic manifestation of the metabolic syndrome, which covers abdominal obesity, insulin resistance, dyslipidemia, glucose intolerance, or type 2 diabetes mellitus. Commensal bacteria modulate the host immune system, protect against exogenous pathogens, and are gatekeepers in intestinal barrier function and maturation. Dysbalanced intestinal microbiota composition influences a variety of NAFLD-associated clinical conditions. Conversely, nutritional supplementation with probiotics and preobiotics impacting composition of gut microbiota can improve the outcome of NAFLD. In crosstalk with the host immune system, the gut microbiota is able to modulate inflammation, insulin resistance, and intestinal permeability. Moreover, the composition of microbiota of an individual is a kind of fingerprint highly influenced by diet. In addition, not only the microbiota itself but also its metabolites influence the metabolism and host immune system. The gut microbiota can produce vitamins and a variety of nutrients including short-chain fatty acids. Holding a healthy balance of the microbiota is therefore highly important. In the present review, we discuss the impact of long-term intake of fructose on the composition of the intestinal microbiota and its biological consequences in regard to liver homeostasis and disease. In particular, we will refer about fructose-induced alterations of the tight junction proteins affecting the gut permeability, leading to the translocation of bacteria and bacterial endotoxins into the blood circulation.