Non-alcoholic Fatty Liver Disease Damage Research Articles

Study of Plasma Pentraxin Levels as a Novel Marker versus Liver Stiffness for Nonalcoholic Steatohepatitis (NASH) in Egyptian Patients

Abstract Background Nonalcoholic fatty liver disease (NAFLD) includes a variety of histopathological findings ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) which can only be differentiated by liver biopsy. There is yet no unique biomarker found to discriminate NASH from simple steatosis. We aimed to investigate the relationship of plasma pentraxin 3 (PTX3) and liver elasticity measured by fibroscan both with the degree of liver damage in NAFLD. Methods Plasma PTX3 levels & fibroscan measurements were estimated in 60 patients with NAFLD (30 with NASH, 30 with non-NASH) and 20 controls Results PTX3 levels were found significantly higher in the NAFLD group than in the control group (3.59 ± 1.77 vs. 1.16 + –0.29 ng/mL, P < 0.001), and in NASH subgroup than non-NASH subgroup (4.97 + –1.36 vs. 21 + –.75 ng/mL, P = 0.001). To discriminate NASH from non-NASH PTX3 had 96.67% sensitivity and 93.33% specificity at the cutoff value of 3.1 ng/mL. Plasma PTX3 levels showed no significant correlation with NAFLD activity score, fibrosis stage and steatosis. Conclusion This study demonstrated markedly higher PTX3 levels in NAFLD patients compared with controls, and in NASH patients compared with non-NASH ones and no correlation wih fibroscan stages. Thus, in this cohort we showed that plasma PTX3 may be a promising biomarker for the presence of NASH.

Analysis of machine learning based integration to identify the crosslink between inflammation and immune response in non-alcoholic fatty liver disease through bioinformatic analysis

BackgroundThe prevalence of nonalcoholic fatty liver disease (NAFLD) is a major form of chronic liver disease. This study aimed to scrutinize the diagnostic biomarkers of NAFLD and their correlation with the immune microenvironment through bioinformatic analysis. MethodsTo identify genes associated with nonalcoholic fatty liver disease (NAFLD), we obtained microarray datasets (GSE63067 and GSE89632) from the Gene Expression Omnibus (GEO) database. Machine learning techniques such as Support Vector Machine (SVM), Least Absolute Shrinkage and Selection Operator (LASSO) and Random Forest (RF) were used to identify key genes. We performed gene ontology analysis to identify the driver pathways of NAFLD. External datasets (merging GSE48452, GSE66676 and GSE135251) were used to validate the identified genes and confirm protein levels by Western blotting. The CIBERSORT algorithm and immune-related techniques, such as ssGSEA, were used to assess the level of infiltration of different immune cell types and their functions. Finally, Spearman's analysis confirmed the relationship between pivotal genes and immune cells. ResultsHub genes (BBOX1, FOSB, NR4A2, RAB26 and SOCS2) were identified as potential biomarkers. This study demonstrates that these hub genes are significantly dysregulated in NAFLD, suggesting that they may be useful as diagnostic indicators and possible targets for treatment. Also covered are their possible effects on inflammation, immune cell activation, and liver damage in NAFLD. A better understanding of the intricate relationship between metabolic inefficiency, immunological response, and liver pathology in NAFLD may be gained from this work, which can lead to the development of new diagnostic tools and clinical treatments. ConclusionThe current study identified BBOX1, FOSB, NR4A2, RAB26 and SOCS2 as important diagnostic biomarkers for NAFLD. The study highlights the important function of immune cell infiltration in developing NAFLD. Their findings provide valuable molecular biological insights into the development of NAFLD and may lead to novel therapeutic strategies for treating this disease.

Navigating the Link Between Non-alcoholic Fatty Liver Disease/Non-alcoholic Steatohepatitis and Cardiometabolic Syndrome.

The global prevalence of non-alcoholic fatty liver disease (NAFLD) is nearly 25% and is increasing rapidly. The spectrum of liver damage in NAFLD ranges from simple steatosis to non-alcoholic steatohepatitis, characterised by the presence of lobular inflammation and hepatocyte ballooning degeneration, with or without fibrosis, which can further develop into cirrhosis and hepatocellular carcinoma. Not only is NAFLD a progressive liver disease, but numerous pieces of evidence also point to extrahepatic consequences. Accumulating evidence suggests that patients with NAFLD are also at increased risk of cardiovascular disease (CVD); in fact, CVDs are the most common cause of mortality in patients with NAFLD. Obesity, type 2 diabetes and higher levels of LDL are common risk factors in both NAFLD and CVD; however, how NAFLD affects the development and progression of CVD remains elusive. In this review, we comprehensively summarise current data on the key extrahepatic manifestations of NAFLD, emphasising the possible link between NAFLD and CVD, including the role of proprotein convertase substilisin/kenin type 9, extracellular vesicles, microbiota, and genetic factors.

Non Alcoholic Fatty Liver Disease (NAFLD) – An Emerging Challenge

A rapidly emerging cause of Chronic Liver Disease (CLD) is Non-alcoholic Fatty Liver Disease (NAFLD). In the West, the prevalence of NAFLD is as high as 30% and it is postulated that it may affect one-third of the population by 2030 [1]. Various studies have shown that the prevalence of NAFLD in Pakistan ranges from 14% to 47% [2]. The spectrum of liver damage in NAFLD is wide-ranging and essentially involves non-alcoholic causes of fat accumulation in the cells of the liver. This can also occur in other conditions where there is more than 5% steatosis. These conditions include chronic liver disease (CLD) caused by drugs (such as Methotrexate, Amiodarone, Tamoxifen etc.) or viruses (such as HCV), exposure to environmental toxins, malnutrition, hemochromatosis, Wilson’s disease, and any autoimmune disease triggering 5% steatosis [3]. There is a strong association of NAFLD with obesity (in more than 40% of patients) [4], hypertriglyceridemia (in 20% or more), diabetes mellitus (in 20% or more), and insulin resistance – all components of the metabolic syndrome [5]. Over the last two decades, rising trends of DM, obesity and insulin resistance have gone hand in hand with increasing prevalence of NAFLD [6]. Pakistan has a 17.1% incidence of Type-2 diabetes and a 14% incidence of NAFLD. There is a 32% incidence of NAFLD in Pakistani type 2 diabetics [7]. The National Health Survey of Pakistan conducted way back in 2006 depicted an incidence of obesity in 25% of the Pakistani population, and since then, numbers have continued to rise.

Cholesterol Exacerbates the Pathophysiology of Non-Alcoholic Steatohepatitis by Upregulating Hypoxia-Inducible Factor 1 and Modulating Microcirculatory Dysfunction.

Cholesterol is a pivotal lipotoxic molecule that contributes to the progression of Non-Alcoholic Steatohepatitis NASH). Additionally, microcirculatory changes are critical components of Non-Alcoholic Fatty Liver Disease (NAFLD) pathogenesis. This study aimed to investigate the role of cholesterol as an insult that modulates microcirculatory damage in NAFLD and the underlying mechanisms. The experimental model was established in male C57BL/6 mice fed a high-fat high-carbohydrate (HFHC) diet for 39 weeks. Between weeks 31-39, 2% cholesterol was added to the HFHC diet in a subgroup of mice. Leukocyte recruitment and hepatic stellate cells (HSC) activation in microcirculation were assessed using intravital microscopy. The hepatic microvascular blood flow (HMBF) was measured using laser speckle flowmetry. High cholesterol levels exacerbated hepatomegaly, hepatic steatosis, inflammation, fibrosis, and leukocyte recruitment compared to the HFHC group. In addition, cholesterol decreased the HMBF-cholesterol-induced activation of HSC and increased HIF1A expression in the liver. Furthermore, cholesterol promoted a pro-inflammatory cytokine profile with a Th1-type immune response (IFN-γ/IL-4). These findings suggest cholesterol exacerbates NAFLD progression through microcirculatory dysfunction and HIF1A upregulation through hypoxia and inflammation. This study highlights the importance of cholesterol-induced lipotoxicity, which causes microcirculatory dysfunction associated with NAFLD pathology, thus reinforcing the potential of lipotoxicity and microcirculation as therapeutic targets for NAFLD.

Dihydrosphingolipids are associated with steatosis and increased fibrosis damage in non-alcoholic fatty liver disease

Dihydrosphingolipids are lipids biosynthetically related to ceramides. An increase in ceramides is associated with enhanced fat storage in the liver, and inhibition of their synthesis is reported to prevent the appearance of steatosis in animal models. However, the precise association of dihydrosphingolipids with non-alcoholic fatty liver disease (NAFLD) is yet to be established. We employed a diet induced NAFLD mouse model to study the association between this class of compounds and disease progression. Mice fed a high-fat diet were sacrificed at 22, 30 and 40 weeks to reproduce the full spectrum of histological damage found in human disease, steatosis (NAFL) and steatohepatitis (NASH) with and without significant fibrosis. Blood and liver tissue samples were obtained from patients whose NAFLD severity was assessed histologically. To demonstrate the effect of dihydroceramides over NAFLD progression we treated mice with fenretinide an inhibitor of dihydroceramide desaturase-1 (DEGS1). Lipidomic analyses were performed using liquid chromatography-tandem mass spectrometry. Triglycerides, cholesteryl esters and dihydrosphingolipids were increased in the liver of model mice in association with the degree of steatosis and fibrosis. Dihydroceramides increased with the histological severity observed in liver samples of mice (0.024 ± 0.003 nmol/mg vs 0.049 ± 0.005 nmol/mg, non-NAFLD vs NASH-fibrosis, p < 0.0001) and patients (0.105 ± 0.011 nmol/mg vs 0.165 ± 0.021 nmol/mg, p = 0.0221). Inhibition of DEGS1 induce a four-fold increase in dihydroceramides improving steatosis but increasing the inflammatory activity and fibrosis. In conclusion, the degree of histological damage in NAFLD correlate with dihydroceramide and dihydrosphingolipid accumulation. Lay summaryAccumulation of triglyceride and cholesteryl ester lipids is the hallmark of non-alcoholic fatty liver disease. Using lipidomics, we examined the role of dihydrosphingolipids in NAFLD progression. Our results demonstrate that de novo dihydrosphingolipid synthesis is an early event in NAFLD and the concentrations of these lipids are correlated with histological severity in both mouse and human disease.

Non-alcoholic fatty liver disease and COVID-19: Harmless companions or disease intensifier?

The pandemics of coronavirus disease 2019 (COVID-19) and non-alcoholic fatty liver disease (NAFLD) coexist. Elevated liver function tests are frequent in COVID-19 and may influence liver damage in NAFLD, while preexisting liver damage from NAFLD may influence the course of COVID-19. However, the prognostic relevance of this interaction, though, is unclear. Obesity is a risk factor for the presence of NAFLD as well as a severe course of COVID-19. Cohort studies reveal conflicting results regarding the influence of NAFLD presence on COVID-19 illness severity. Striking molecular similarities of cytokine pathways in both diseases, including postacute sequelae of COVID-19, suggest common pathways for chronic low-activity inflammation. This review will summarize existing data regarding the interaction of both diseases and discuss possible mechanisms of the influence of one disease on the other.

The hepatic integrated stress response suppresses the somatotroph axis to control liver damage in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) can be ameliorated by calorie restriction, which leads to the suppressed somatotroph axis. Paradoxically, the suppressed somatotroph axis is associated with patients with NAFLD and is correlated with the severity of fibrosis. How the somatotroph axis becomes dysregulated and whether the repressed somatotroph axis impacts liver damage during the progression of NAFLD are unclear. Here, we identify a regulatory branch of the hepatic integrated stress response (ISR), which represses the somatotroph axis in hepatocytes through ATF3, resulting in enhanced cell survival and reduced cell proliferation. In mouse models of NAFLD, the ISR represses the somatotroph axis, leading to reduced apoptosis and inflammation but decreased hepatocyte proliferation and exacerbated fibrosis in the liver. NAD+ repletion reduces the ISR, rescues the dysregulated somatotroph axis, and alleviates NAFLD. These results establish that the hepatic ISR suppresses the somatotroph axis to control cell fate decisions and liver damage in NAFLD.

Imaging Mass Spectrometry Reveals Alterations in N-Linked Glycosylation That Are Associated With Histopathological Changes in Nonalcoholic Steatohepatitis in Mouse and Human

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD) and is characterized by inflammation, hepatocyte injury, and fibrosis. Further, NASH is a risk factor for cirrhosis and hepatocellular carcinoma. Previous research demonstrated that serum N-glycan profiles can be altered in NASH patients. Here, we hypothesized that these N-glycan modifications may be associated with specific liver damage in NAFLD and NASH. To investigate the N-glycome profile in tissue, imaging mass spectrometry was used for a qualitative and quantitative in situ N-linked glycan analysis of mouse and human NAFLD/NASH tissue. A murine model was used to induce NAFLD and NASH through ad libitum feeding with either a high-fat diet or a Western diet, respectively. Mice fed a high-fat diet or Western diet developed inflammation, steatosis, and fibrosis, consistent with NAFLD/NASH phenotypes. Induction of NAFLD/NASH for 18 months using high caloric diets resulted in increased expression of mannose, complex/fucosylated, and hybrid N-glycan structures compared to control mouse livers. To validate the animal results, liver biopsy specimens from 51 human NAFLD/NASH patients representing the full range of NASH Clinical Research Network fibrosis stages were analyzed. Importantly, the same glycan alterations observed in mouse models were observed in human NASH biopsies and correlated with the degree of fibrosis. In addition, spatial glycan alterations were localized specifically to histopathological changes in tissue like fibrotic and fatty areas. We demonstrate that the use of standard staining’s combined with imaging mass spectrometry provide a full profile of the origin of N-glycan modifications within the tissue. These results indicate that the spatial distribution of abundances of released N-glycans correlate with regions of tissue steatosis associated with NAFLD/NASH.

Non-Alcoholic Fatty Liver Disease (NAFLD) in Patients with Psoriasis: A Review of the Hepatic Effects of Systemic Therapies.

There is increasing interest in the association between psoriasis and non-alcoholic fatty liver disease (NAFLD), which is a prevalent liver disease characterized by excessive fat storage and inflammation that can progress to fibrosis and cancer. Patients with psoriasis have a two-fold higher risk to develop NAFLD and a higher risk to progress to more severe liver disease. Psoriasis and NAFLD share common risk factors such as smoking, alcohol consumption, and the presence of metabolic syndrome and its component disorders. In addition, both psoriasis and NAFLD hinge upon a systemic low-grade inflammation that can lead to a vicious cycle of progressive liver damage in NAFLD as well as worsening of the underlying psoriasis. Other important shared pathophysiological pathways include peripheral insulin resistance and oxidative stress. NAFLD should receive clinical awareness as important comorbidity in psoriasis. In this review, we assess the recent literature on the epidemiological and pathophysiological relationship of psoriasis and NAFLD, discuss the clinical implications of NAFLD in psoriasis patients, and summarize the hepatotoxic and hepatoprotective potential of systemic psoriasis therapies.

The rs599839 A>G Variant Disentangles Cardiovascular Risk and Hepatocellular Carcinoma in NAFLD Patients.

Simple SummaryDyslipidemia is a hallmark of nonalcoholic fatty liver disease (NAFLD) and the rs599839 variant in the CELSR2-PSRC1-SORT1 genetic cluster, has been associated with a protection against cardiovascular events. Here, we revealed a novel link between the rs599839 variant and hepatocellular carcinoma (HCC) whose onset in the context of NAFLD is rapidly increasing. We found that the rs599839 variant disentangled the risk of HCC from that of cardiovascular abnormalities by modulating SORT1 and PSRC1 expressions. The latter emerged as a potential modifier of liver carcinogenesis.Background and Aims: Dyslipidemia and cardiovascular diseases (CVD) are comorbidities of nonalcoholic fatty liver disease (NAFLD), which ranges from steatosis to hepatocellular carcinoma (HCC). The rs599839 A>G variant, in the CELSR2-PSRC1-SORT1 gene cluster, has been associated CVD, but its impact on metabolic traits and on the severity liver damage in NAFLD has not been investigated yet. Methods: We evaluated the effect of the rs599839 variant in 1426 NAFLD patients (Overall cohort) of whom 131 had HCC (NAFLD-HCC), in 500,000 individuals from the UK Biobank Cohort (UKBBC), and in 366 HCC samples from The Cancer Genome Atlas (TCGA). Hepatic PSRC1, SORT1 and CELSR2 expressions were evaluated by RNAseq (n = 125). Results: The rs599839 variant was associated with reduced circulating LDL, carotid intima-media thickness, carotid plaques and hypertension (p < 0.05) in NAFLD patients and with protection against dyslipidemia in UKBBC. The minor G allele was associated with higher risk of HCC, independently of fibrosis severity (odds ratio (OR): 5.62; 95% c.i. 1.77–17.84, p = 0.003), poor prognosis and advanced tumor stage (p < 0.05) in the overall cohort. Hepatic PSRC1, SORT1 and CELSR2 expressions were increased in NAFLD patients carrying the rs599839 variant (p < 0.0001). SORT1 mRNA levels negatively correlated with circulating lipids and with those of genes involved in lipoprotein turnover (p < 0.0001). Conversely, PSRC1 expression was positively related to that of genes implicated in cell proliferation (p < 0.0001). In TCGA, PSRC1 over-expression promoted more aggressive HCC development (p < 0.05). Conclusions: In sum, the rs599839 A>G variant is associated with protection against dyslipidemia and CVD in NAFLD patients, but as one it might promote HCC development by modulating SORT1 and PSRC1 expressions which impact on lipid metabolism and cell proliferation, respectively.

IL-18 but Not IL-1 Signaling Is Pivotal for the Initiation of Liver Injury in Murine Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is rising in prevalence, and a better pathophysiologic understanding of the transition to its inflammatory phenotype (NASH) is key to the development of effective therapies. To evaluate the contribution of the NLRP3 inflammasome and its downstream effectors IL-1 and IL-18 in this process, we applied the true-to-life “American lifestyle-induced obesity syndrome” (ALiOS) diet mouse model. Development of obesity, fatty liver and liver damage was investigated in mice fed for 24 weeks according to the ALiOS protocol. Lipidomic changes in mouse livers were compared to human NAFLD samples. Receptor knockout mice for IL-1 and IL-18 were used to dissect the impact of downstream signals of inflammasome activity on the development of NAFLD. The ALiOS diet induced obesity and liver steatosis. The lipidomic changes closely mimicked changes in human NAFLD. A pro-inflammatory gene expression pattern in liver tissue and increased serum liver transaminases indicated early liver damage in the absence of histological evidence of NASH. Mechanistically, Il-18r−/−- but not Il-1r−/− mice were protected from early liver damage, possibly due to silencing of the pro-inflammatory gene expression pattern. Our study identified NLRP3 activation and IL-18R-dependent signaling as potential modulators of early liver damage in NAFLD, preceding development of histologic NASH.

Can portal vein pulsatility index be used as predictive parameter with hepatic artery resistive index for liver fibrosis in nonalcoholic hepatosteatosis?

Aim: Nonalcoholic fatty liver disease (NAFLD) is a clinical entity with a broad spectrum of isolated liver steatosis, steatohepatitis and even cirrhosis. In the development of hepatitis or cirrhosis, flow changes in the hepatic artery and portal vein may be detected. The aim of this study was to investigate the significance of the changes in hemodynamic findings according to the steatosis grade in patients with nonalcoholic hepatosteatosis. Materials and Methods: the study was performed with B-mode and Doppler ultrasonographic (US) measurements of patients who applied to the radiology department for abdominal ultrasonography examination between February and September 2018. Hepatic artery resistive index (HARI) and portal vein pulsatility index (PVPI) were evaluated. Thirty patients without steatosis and 30 patients from each 3 hepatosteatosis grade were included into the study. As the criteria for inclusion of patients in the study, there was no history of additional disease. p&amp;lt;0.05 values were considered statistically significant. Results: HARI was significantly lower in grade 3 steatosis than the control group, grade 1 and 2 steatosis (p&amp;lt;0.05). In grade 3 steatosis, portale vein diameter was significantly wider than the control group, grade 1 and 2 steatosis (p&amp;lt;0.05). PVPI was significantly lower in grade 2 steatosis than the control group and grade 1 steatosis (p&amp;lt;0.05). Significant hemodynamic changes were detected in the hepatic artery and portal vein when compared with control and patients groups. Conclusion: The evaluation of PVPI is considered as a noninvasive valuable method as if HARI in the evaluation of liver parenchymal damage in NAFLD.

Mitochondrial oxidative injury: a key player in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent liver disease worldwide. NAFLD is tightly linked to the metabolic syndrome, insulin resistance, and oxidative stress. Globally, its inflammatory form, nonalcoholic steatohepatitis (NASH), has become the main cause of liver-related morbidity and mortality, mainly due to liver cirrhosis and primary liver cancer. One hallmark of NASH is the presence of changes in mitochondrial morphology and function that are accompanied by a blocked flow of electrons in the respiratory chain, which increases formation of mitochondrial reactive oxygen species in a self-perpetuating vicious cycle. Consequences are oxidation of DNA bases and mitochondrial DNA depletion that are coupled with genetic and acquired mitochondrial DNA mutations, all impairing the resynthesis of respiratory chain polypeptides. In general, several maladaptations of pathways that usually maintain energy homeostasis occur with the early and late excess metabolic stress in NAFLD and NASH. We discuss the interplay between hepatocyte mitochondrial stress and inflammatory responses, focusing primarily on events initiated and maintained by mitochondrial free radical-induced damage in NAFLD. Importantly, mitochondrial oxidative stress and dysfunction are modulated by key pharmacological targets that are related to excess production of reactive oxygen species, mitochondrial turnover and the mitochondrial unfolded protein response, mitophagy, and mitochondrial biogenesis. However, the efficacy of such interventions depends on NAFLD/NASH disease stage.

β-Klotho gene variation is associated with liver damage in children with NAFLD

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in adults and children. Along with obesity, diabetes and insulin resistance, genetic factors strongly impact on NAFLD development and progression. Dysregulated bile acid metabolism and the fibroblast growth factor 19 (FGF19) pathway play a pivotal role in NAFLD pathogenesis. However, the mechanism through which the FGF19 receptor system is associated with liver damage in NAFLD remains to be defined. We evaluated the impact of the rs17618244 G>A β-Klotho (KLB) variant on liver damage in 249 pediatric patients with biopsy-proven NAFLD and the association of this variant with the expression of hepatic and soluble KLB. In vitro models were established to investigate the role of the KLB mutant. The KLB rs17618244 variant was associated with an increased risk of ballooning and lobular inflammation. KLB plasma levels were lower in carriers of the rs17618244 minor A allele and were associated with lobular inflammation, ballooning and fibrosis. In HepG2 and Huh7 hepatoma cell lines, exposure to free fatty acids caused a severe reduction of intracellular and secreted KLB. Finally, KLB downregulation obtained by the expression of a KLB mutant in HepG2 and Huh7 cells induced intracellular lipid accumulation and upregulation of p62, ACOX1, ACSL1, IL-1β and TNF-α gene expression. In conclusion, we showed an association between the rs17618244 KLB variant, which leads to reduced KLB expression, and the severity of NAFLD in pediatric patients. We can speculate that the KLB protein may exert a protective role against lipotoxicity and inflammation in hepatocytes. Genetic and environmental factors strongly impact on the pathogenesis and progression of non-alcoholic fatty liver disease (NAFLD). The FGF19/FGFR4/KLB pathway plays a pivotal role in the pathogenesis of NAFLD. The aim of the study was to investigate the impact of a genetic variant in the KLB gene on the severity of liver disease. Our data suggest that the KLB protein plays a protective role against lipotoxicity and inflammation in hepatocytes.

Associations of Plasma CD36 and Body Fat Distribution.

CD36 is a class B scavenger-receptor involved in the uptake of fatty acids in liver and adipose tissue. It is unknown whether plasma CD36 levels are related to liver fat content or adipose tissue in the general population. We measured plasma CD36 from 575 participants of the community-based PopGen cohort who underwent MRI to quantify visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and liver signal intensity (LSI), a proxy for liver fat content. Nonalcoholic fatty liver disease (NAFLD) was defined as LSI ≥3.0 in the absence of high alcohol intake. The relations between plasma CD36 and body mass index (BMI), VAT, SAT, LSI, and NAFLD were evaluated via multivariable-adjusted linear and logistic regression analysis. Plasma CD36 concentrations were correlated with BMI (r = 0.11; P = 0.01), SAT (r = 0.16; P < 0.001), and VAT (r = 0.15, P < 0.001) but not with LSI (P = 0.44). In multivariable-adjusted regression models, mean BMI values rose across CD36 quartiles [quartile 1 (Q1), 27.8 kg/m2; Q4, 28.9 kg/m2; P-trend = 0.013). Similarly, VAT (Q1, 4.13 dm3; Q4, 4.71 dm3; P-trend < 0.001), and SAT (Q1, 7.61 dm3; Q4, 8.74 dm3; P-trend < 0.001) rose across CD36 quartiles. Plasma CD36 concentrations were unrelated to LSI (P-trend = 0.36) and NAFLD (P-trend = 0.64). Participants with NAFLD and elevated alanine aminotransferase (ALT), a marker for liver damage, had higher CD36 compared with participants with NAFLD and normal ALT. Higher plasma concentrations of CD36 were associated with greater general and abdominal adiposity but not with liver fat content or NAFLD in this community-based sample. However, plasma CD36 may reflect more severe liver damage in NAFLD.

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.

Vitamin D Supplementation and Non-Alcoholic Fatty Liver Disease: Present and Future.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic hepatic disease throughout the Western world and is recognized as the main cause of cryptogenic cirrhosis; however, the identification of an effective therapy for NAFLD is still a major challenge. Vitamin D deficiency is a wide-spread condition which reaches epidemic proportions in industrialized countries, mainly in relation to current lifestyle and limited dietary sources. Epidemiological studies point towards an association between hypovitaminosis D and the presence of NAFLD and steatohepatitis (NASH), independently of confounders such as obesity and insulin resistance. Furthermore, several pieces of experimental data have shown the anti-fibrotic, anti-inflammatory and insulin-sensitizing properties exerted by vitamin D on hepatic cells. However, results from trials evaluating the effects of oral vitamin D supplementation on liver damage in NAFLD and NASH are controversial. The aim of this review is to give an overview of the evidence currently available from clinical trials and to discuss possible shortcomings and new strategies to be considered in future investigations.

ER stress-mediated cell damage contributes to the release of EDA+ fibronectin from hepatocytes in nonalcoholic fatty liver disease.

Fibronectin containing extra domain A (EDA+ FN), a functional glycoprotein participating in several cellular processes, correlates with chronic liver disease. Herein, we aim to investigate the expression and secretion of EDA+ FN from hepatocytes in nonalcoholic fatty liver disease (NAFLD) and the underlying mechanisms. Circulating levels of EDA+ FN were determined by ELISA in clinical samples. Western blotting and flow cytometry were performed on L02 and HepG2 cell lines to analyze whether the levels of EDA+ FN were associated with endoplasmic reticulum (ER) stress-related cell death. Circulating levels of EDA+ FN in NAFLD patients were significantly higher than those in control subjects, and positively related with severity of ultrasonographic steatosis score. In cultured hepatocytes, palmitate up-regulated the expression of EDA+ FN in a dose-dependent manner. Conversely, when the cells were pretreated with 4-phenylbutyrate, a specific inhibitor of ER stress, up-regulation of EDA+ FN could be abrogated. Moreover, silencing CHOP by shRNA enhanced the release of EDA+ FN from hepatocytes following palmitate treatment, which was involved in ER stress-related cell damage. These findings suggest that the up-regulated level of EDA+ FN is associated with liver damage in NAFLD, and ER stress-mediated cell damage contributes to the release of EDA+ FN from hepatocytes.

Effects of Phlebotomy on Liver Enzymes and Histology of Patients with Nonalcoholic Fatty Liver Disease

Background:Nonalcoholic fatty liver disease (NAFLD), defined as excessive liver fat deposition and one of end-stage liver disease causes. Increased ferritin levels are associated with insulin resistance and a higher hepatic iron and fat content. Hyperferritinemia has been associated with severity of liver damage in NAFLD. The study aimed to evaluate the effects of phlebotomy on liver enzymes and histology in such patients.Materials and Methods:Thirty-two eligible patients who had NAFLD and after 6 months of lifestyle modification still had NAFLD, and whose ferritin serum was above 250 mg/dl, were enrolled in this clinical trial study. After written informed consent was obtained, each patient's blood serum was taken for aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALK-P), complete blood count (CBC), total iron-binding capacity (TIBC), iron, and ferritin. Then the patients underwent liver biopsy. After that patients underwent phlebotomy, giving 350 cc blood monthly. Before every phlebotomy, hemoglobin and ferritin were checked. If they were in the goal range, phlebotomy was discontinued and the patient underwent liver biopsy. A serum sample was taken for testing at the beginning of the study. The results before and after phlebotomy were compared. The maximum duration of the study was 6 months.Results:Thirty-two patients (26 males and 6 females) were enrolled, and the mean average age was 33.7 ± 6.74 years. Phlebotomy improved liver enzymes and histology of liver significantly (P < 0.001) and induced reduction of ferritin.Conclusion:Phlebotomy is effective for the improvement of liver enzymes and histology in patients with NAFLD and hyperferritinemia.