Non-alcoholic Fatty Liver Disease Phenotype Research Articles

Gene-metabolite network analysis in different nonalcoholic fatty liver disease phenotypes

We sought to identify common key regulators and build a gene-metabolite network in different nonalcoholic fatty liver disease (NAFLD) phenotypes. We used a high-fat diet (HFD), a methionine-choline-deficient diet (MCDD) and streptozocin (STZ) to establish nonalcoholic fatty liver (NAFL), nonalcoholic steatohepatitis (NASH) and NAFL+type 2 diabetes mellitus (T2DM) in rat models, respectively. Transcriptomics and metabolomics analyses were performed in rat livers and serum. A functional network-based regulation model was constructed using Cytoscape with information derived from transcriptomics and metabolomics. The results revealed that 96 genes, 17 liver metabolites and 4 serum metabolites consistently changed in different NAFLD phenotypes (>2-fold, P<0.05). Gene-metabolite network analysis identified ccl2 and jun as hubs with the largest connections to other genes, which were mainly involved in tumor necrosis factor, P53, nuclear factor-kappa B, chemokine, peroxisome proliferator activated receptor and Toll-like receptor signaling pathways. The specifically regulated genes and metabolites in different NAFLD phenotypes constructed their own networks, which were mainly involved in the lipid and fatty acid metabolism in HFD models, the inflammatory and immune response in MCDD models, and the AMPK signaling pathway and response to insulin in HFD+STZ models. Our study identified networks showing the general and specific characteristics in different NAFLD phenotypes, complementing the genetic and metabolic features in NAFLD with hepatic and extra-hepatic manifestations.

Hepatic rhythmicity of endoplasmic reticulum stress is disrupted in perinatal and adult mice models of high-fat diet-induced obesity

We investigated the regulation of hepatic ER stress in healthy liver and adult or perinatally programmed diet-induced non-alcoholic fatty liver disease (NAFLD). Female mice were fed either obesogenic or control diet before mating, during pregnancy and lactation. Post-weaning, offspring from each maternal group were divided into either obesogenic or control diet. At six months, offspring were sacrificed at 4-h intervals over 24 h. Offspring fed obesogenic diets developed NAFLD phenotype, and the combination of maternal and offspring obesogenic diets exacerbated this phenotype. UPR signalling pathways (IREα, PERK, ATF6) and their downstream regulators showed different basal rhythmicity, which was modified in offspring exposed to obesogenic diet and maternal programming. The double obesogenic hit increased liver apoptosis measured by TUNEL staining, active caspase-3 and phospho-JNK and GRP78 promoter methylation levels. This study demonstrates that hepatic UPR is rhythmically activated. The combination of maternal obesity (MO) and obesogenic diets in offspring triggered altered UPR rhythmicity, DNA methylation and cellular apoptosis.

The role of mitochondrial genomics in patients with non-alcoholic steatohepatitis (NASH).

BackgroundVisceral obesity and metabolic syndrome are commonly associated with non-alcoholic fatty liver disease (NAFLD). The progression of steatosis to NASH depends on a number of metabolic and patient-related factors. The mechanisms of genetic predisposition towards the development of NASH and related fibrosis remain unclear. In this study, our aim was to utilize mitotyping and identify mitochondrial haplotypes that may be associated with NAFLD.MethodsWe examined mitochondrial haplotypes along with patatin-like phospholipase domain containing 3 (PNPLA3) rs738409 genotype to determine their association with NAFLD phenotypes. Whole blood samples were obtained from 341 patients (BMI > 35) undergoing weight reduction surgery after written consent. Liver biopsies were centrally reviewed by a single pathologist based on predetermined pathologic protocol (41.9 % Non-NASH NAFLD, 30.4 % NASH, 27.5 % controls). A 1,122 bp of the mitochondrial control loop was sequenced for each sample and classified into haplogroups.ResultsThe presence of haplogroup L exhibits protection against the development of NASH and pericellular fibrosis. The alleles of PNPLA3 locus showed differential distribution in cohorts with NAFLD, NASH and pericellular fibrosis. Heterozygosity at this locus is independently associated with higher risk of having NASH and pericellular fibrosis.ConclusionMitochondrial genetics play an important role in NASH probably by modulation of oxidative stress and the efficiency of oxidative phosphorylation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-016-0324-0) contains supplementary material, which is available to authorized users.

Male 11β-HSD1 Knockout Mice Fed Trans-Fats and Fructose Are Not Protected From Metabolic Syndrome or Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) defines a spectrum of conditions from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis and is regarded as the hepatic manifestation of the metabolic syndrome. Glucocorticoids can promote steatosis by stimulating lipolysis within adipose tissue, free fatty acid delivery to liver and hepatic de novo lipogenesis. Glucocorticoids can be reactivated in liver through 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme activity. Inhibition of 11β-HSD1 has been suggested as a potential treatment for NAFLD. To test this, male mice with global (11β-HSD1 knockout [KO]) and liver-specific (LKO) 11β-HSD1 loss of function were fed the American Lifestyle Induced Obesity Syndrome (ALIOS) diet, known to recapitulate the spectrum of NAFLD, and metabolic and liver phenotypes assessed. Body weight, muscle and adipose tissue masses, and parameters of glucose homeostasis showed that 11β-HSD1KO and LKO mice were not protected from systemic metabolic disease. Evaluation of hepatic histology, triglyceride content, and blinded NAFLD activity score assessment indicated that levels of steatosis were similar between 11β-HSD1KO, LKO, and control mice. Unexpectedly, histological analysis revealed significantly increased levels of immune foci present in livers of 11β-HSD1KO but not LKO or control mice, suggestive of a transition to NASH. This was endorsed by elevated hepatic expression of key immune cell and inflammatory markers. These data indicate that 11β-HSD1-deficient mice are not protected from metabolic disease or hepatosteatosis in the face of a NAFLD-inducing diet. However, global deficiency of 11β-HSD1 did increase markers of hepatic inflammation and suggests a critical role for 11β-HSD1 in restraining the transition to NASH.

Hepatic NAD(+) deficiency as a therapeutic target for non-alcoholic fatty liver disease in ageing.

Ageing is an important risk factor of non-alcoholic fatty liver disease (NAFLD). Here, we investigated whether the deficiency of nicotinamide adenine dinucleotide (NAD(+) ), a ubiquitous coenzyme, links ageing with NAFLD. Hepatic concentrations of NAD(+) , protein levels of nicotinamide phosphoribosyltransferase (NAMPT) and several other critical enzymes regulating NAD(+) biosynthesis, were compared in middle-aged and aged mice or patients. The influences of NAD(+) decline on the steatosis and steatohepatitis were evaluated in wild-type and H247A dominant-negative, enzymically-inactive NAMPT transgenic mice (DN-NAMPT) given normal or high-fat diet (HFD). Hepatic NAD(+) level decreased in aged mice and humans. NAMPT-controlled NAD(+) salvage, but not de novo biosynthesis pathway, was compromised in liver of elderly mice and humans. Given normal chow, middle-age DN-NAMPT mice displayed systemic NAD(+) reduction and had moderate NAFLD phenotypes, including lipid accumulation, enhanced oxidative stress, triggered inflammation and impaired insulin sensitivity in liver. All these NAFLD phenotypes, especially release of pro-inflammatory factors, Kupffer cell accumulation, monocytes infiltration, NLRP3 inflammasome pathway and hepatic fibrosis (Masson's staining and α-SMA staining), deteriorated further under HFD challenge. Oral administration of nicotinamide riboside, a natural NAD(+) precursor, completely corrected these NAFLD phenotypes induced by NAD(+) deficiency alone or HFD, whereas adenovirus-mediated SIRT1 overexpression only partially rescued these phenotypes. These results provide the first evidence that ageing-associated NAD(+) deficiency is a critical risk factor for NAFLD, and suggest that supplementation with NAD(+) substrates may be a promising therapeutic strategy to prevent and treat NAFLD.

The Early Origins of NAFLD in Humans and Non‐Human Primates

Non‐Alcoholic Fatty Liver Disease (NAFLD) is now the most common liver disease worldwide in children and adults. Even more concerning is that the risk factors for NAFLD may start operating in early life. In the U.S., up to 25% of children are already overweight or obese entering kindergarten, and maternal obesity is consistently one of the most powerful predictors of pediatric obesity and its complications. NAFLD is currently estimated to occur in 25–50% of obese children with lifetime consequences, including liver NASH and hepatic carcinoma risk. Our group has spent the past decade studying developmental programming in humans, non‐human primates (NHP), and transgenic mouse models. We have shown that maternal Western‐Style Diet (WSD) in NHP mothers results in a NAFLD phenotype in the fetus, beginning in the early 3rd trimester. This phenotype persists in juveniles up to 14 months of age despite weaning to a healthy diet, and in the absence of obesity. Our compelling human data in neonates born to obese/Gestational Diabetic mothers demonstrate increased intrahepatic fat using MRI/MRS at 2 wks of life. However not everyone who is born to an obese mother develops disease, with other potential contributing factors particularly excessive maternal insulin resistance, hypoxia, and mitochondria dysfunction important in the fetal development of NAFLD. Our studies in obese NHP mothers using the anti‐oxidant resveratrol, may be able to mitigate some of these complications to prevent the early complications of maternal obesity on the developing liver. Interestingly, founding individual microbiota composition in infants reflects the maternal transfer during or immediately after birth. The intestinal microflora is different between individuals and its composition is largely dependent on a combination of genetics, diet and lifestyle choices. Although no single commensal bacteria species have been conclusively proven to provoke NAFLD, lack of certain bacterial species has been observed with human patients prone to or suffering from this disorder. In cross‐sectional studies comparing vaginally delivered, exclusively breast fed infants we have found a significant reduction in the early pioneering bacteria Gammaproteobacteria in 2 week old infants from obese mothers compared to infants born to normal weight mothers. Further, gnotobiotic transfer of stool from infants of obese mothers into germ‐free mice was associated with a significant reduction in IL‐10 producing anti‐inflammatory Treg cells, as well as CD3+CD4+ helper T‐cells and ER stress in the liver at 21 days post‐transplantation. These findings suggest that early commensal bacteria from obese human infants may be important in conditioning a developing immune system that educates inflammatory cells, leading to inflammation‐linked diseases, including NAFLD, a hypothesis we are currently exploring.Support or Funding InformationNIH‐NIDDK, ADA, and Bill Gates Foundation

Genetic influences in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is a metabolic liver disease with widely variable phenotypes extending from simple steatosis, through nonalcoholic steatohepatitis (NASH) to cirrhosis and hepatocellular carcinoma. Inevitably, this reflects the interplay of well-recognized environmental factors and disease associations such as obesity and insulin resistance with host genetic factors, which are polygenic or complex in nature. Most of the observed phenotypic variability will probably be explained by variations in single nucleotide polymorphism frequency, although knowledge of the effect of most polymorphisms on biologic function is currently limited. Several observational studies of kindred with NASH suggest a genetic contribution. Most data characterizing genetic variation in different NAFLD phenotypes is derived from case-control association studies involving putative candidate genes. These candidate genes have been selected largely based upon the "two-hit hypothesis" of the pathogenesis of NAFLD, although other hypothesis-independent approaches can also be informative in gene selection. Thus far, candidate gene association studies have had significant limitations such as small cohort sizes and poor reproducibility. Rapid technologic developments are increasing the capability of detecting genetic variation. Identification of the genetic contribution to NAFLD will inform theories of disease pathogenesis and progression and ultimately improve management.

Comparisons of dietary intake in Japanese with non-alcoholic fatty liver disease and type 2 diabetes mellitus.

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease that involves a complex interaction between genetics, diet, and lifestyle, all of which combine to form the NAFLD phenotype. In Japan, medical nutrition therapy for NAFLD has not yet been established, so NAFLD patients are instructed in the dietary modifications used for type 2 diabetes mellitus (T2DM). Because points of difference may exist in the effects of dietary choices on NAFLD and T2DM, the present study aimed to compare and assess the dietary intake of Japanese individuals with NAFLD and T2DM. This cross-sectional study involved 219 patients (77 NAFLD subjects; 33 males, 44 females; 142 T2DM subjects: 76 males, 66 females) aged 40–79 years. Dietary intake was assessed using a validated self-administered diet history questionnaire. Among the results, the most notable in NAFLD patients relative to T2DM patients were: 1) the low intake of vegetables that can reduce the overall energy density; 2) the high consumption of fruits and confectionery containing simple carbohydrates such as fructose; and 3) BMI may be higher. We demonstrated differences in dietary selection between the two groups. NAFLD patients were more likely to have dietary habits that promote fat accumulation in the body.

Genetic and epigenetic mechanisms of NASH.

Along with the obesity epidemic, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased exponentially. The histological disease spectrum of NAFLD ranges from bland fatty liver (hepatic steatosis), to the concomitant presence of inflammation and ballooning which defines nonalcoholic steatohepatitis (NASH). The latter can progress in a subset to fibrosis, leading ultimately to cirrhosis and hepatocellular carcinoma. The past decade has seen tremendous advances in our understanding of the genetic and epigenetic bases of NAFLD, mainly through the application of high end technology platforms including genome-wide association studies (GWAS). These have helped to define common gene variants (minor allele frequency >5%) that contribute to the NAFLD phenotype. Looking to the future, these discoveries are expected to lead to improved diagnostics, the personalization of medicine, and a better understanding of the pathophysiological underpinnings that drive the transition from NAFLD to steatohepatitis and fibrosis, leading to the identification of novel therapeutic targets. In this review, we summarize data on the current state of knowledge with regard to the genetic and epigenetic mechanisms for the development of NASH.

Polyphenols and non-alcoholic fatty liver disease: impact and mechanisms.

Non-alcoholic fatty liver disease (NAFLD) is considered to be the hepatic component of the metabolic syndrome and its prevalence is rapidly increasing due to its strong association with insulin resistance and obesity. At present, given that NAFLD is highly prevalent and therapies are limited, much attention is focused on identifying effective dietary strategies for the prevention and treatment of the disease. Polyphenols are a group of plant bioactive compounds whose regular consumption have been associated with a reduction in the risk of a number of metabolic disorders associated with NAFLD. Here we review the emerging and relatively consistent evidence from cell culture and rodent studies showing that select polyphenols positively modulate a variety of contributors to the NAFLD phenotype, through diverse and complementary mechanisms of action. In particular, the reduction of de novo lipogenesis (via sterol regulatory element-binding protein 1c) and increased fatty acid β-oxidation, presumably involving AMP-activated protein kinase activation, will be discussed. The indirect antioxidant and anti-inflammatory properties of polyphenols which have been reported to contribute to the amelioration of NAFLD will also be addressed. In addition to a direct study of the liver, rodent studies have provided insight into the impact of polyphenols on adipose tissue function and whole body insulin sensitivity, which are likely to in part modulate their impact on NAFLD development. Finally an overview of the limited data from clinical trials will be given along with a discussion of the dose extrapolation from animal studies to human subjects.

Fructose and liver function--is this behind nonalcoholic liver disease?

The purpose was to summarize recent advances in the understanding of nonalcoholic fatty liver disease (NAFLD) pathophysiology and the role of fructose in NAFLD. Epidemiological studies continue to point to a strong association between high fructose intake and NAFLD and its severity. New studies of NAFLD reveal the importance of upregulated de novo lipogenesis as a key feature in its pathophysiology along with increased visceral adiposity and alteration of gut microbiome. Studies of fructose in NAFLD show how this nutrient may uniquely exacerbate the phenotype of NAFLD. The timing of exposure to fructose may be important with early (in utero) exposure being particularly harmful. Fructose is a potentially modifiable environmental exposure that appears to exacerbate NAFLD through multiple mechanisms. Although larger, longer clinical studies are still needed, it appears that limitation of fructose sources in the diet is beneficial in NAFLD.

Epicardial Fat in Nonalcoholic Fatty Liver Disease: Properties and Relationships With Metabolic Factors, Cardiac Structure, and Cardiac Function.

Nonalcoholic fatty liver disease (NAFLD) is closely related to insulin resistance and the metabolic syndrome and might be an important cardiovascular (CV) risk factor. Epicardial adipose tissue (EAT) has been implicated in the pathogenesis of obesity-related CV disease. In an NAFLD population, we investigated EAT thickness and its possible relations to NAFLD and cardiac structure and function. This was an observational study of 57 patients with NAFLD and 48 age-matched controls. Patients with NAFLD had significantly higher body mass index (P < .0001), waist circumference (P < .0001), and high-sensitivity C-reactive protein (P = .005), whereas high-density lipoprotein cholesterol (P = .01) and adiponectin (P = .005) levels were significantly lower. The EAT was not thicker in NAFLD but was positively related to indices of impaired glucose tolerance and inflammation, with diabetes being an independent predictor of EAT thickness (b* = 0.29, P = .04). No relations were found between EAT and cardiac structure and function. In conclusion, this study confirms a pathologic phenotype of NAFLD. Epicardial fat was not significantly related to NAFLD per se, but diabetes, glucose metabolism, and inflammation were closely related to its thickness.

Activation of the GP130-STAT3 axis and its potential implications in nonalcoholic fatty liver disease.

The status of the GP130-STAT3 signaling pathway in humans with nonalcoholic fatty liver disease (NAFLD) and its relevance to disease pathogenesis are unknown. The expression of the gp130-STAT3 axis and gp130 cytokine receptors were studied in subjects with varying phenotypes of NAFLD including nonalcoholic steatohepatitis (NASH) and compared with lean and weight-matched controls without NAFLD. Gp130 and its downstream signaling element (Tyk2 and STAT3) expression were inhibited in obese controls whereas they were increased in NAFLD. IL-6 levels were increased in NASH and correlated with gp130 expression (P < 0.01). Palmitate inhibited gp130-STAT3 expression and signaling. IL-6 and palmitate inhibited hepatic insulin signaling via STAT3-dependent and independent mechanisms, respectively. STAT3 overexpression reversed palmitate-induced lipotoxicity by increasing autophagy (ATG7) and decreasing endoplasmic reticulum stress. These data demonstrate that the STAT3 pathway is activated in NAFLD and can worsen insulin resistance while protecting against other lipotoxic mechanisms of disease pathogenesis.

Implication of Gut Microbiota in Nonalcoholic Fatty Liver Disease

It is now well established that gut flora and chronic liver diseases are closely interrelated. This association is most evident at late stages of the disease: cirrhosis and impaired liver function are associated with intestinal bacterial overgrowth, small bowel dysmotility, increased gut permeability, and decreased immunological defenses, all of which promote bacterial translocation from the gut to the systemic circulation, leading to infections that in turn aggravate liver dysfunction in a vicious circle [1]. For a long time, the implication of gut flora in the pathophysiology of less advanced chronic liver diseases has been underestimated because technical limitations allow only for the culture of a small fraction of gut bacteria. Recent technological progress and next-generation DNA sequencing have allowed for more sophisticated analysis and sampling of the gut microbiota by culture-independent methods [2]. Thanks to these recent technological advances, knowledge about the role of gut microbiota disruption (dysbiosis) in gut diseases such as colon cancer, inflammatory bowel diseases, and irritable bowel syndrome has greatly increased, with possible new therapeutic strategies. More surprisingly, gut dysbiosis has been implicated in chronic metabolic disorders such as obesity, metabolic syndrome, diabetes, and cardiovascular diseases [3]. Nonalcoholic fatty liver disease (NAFLD) is the liver manifestation of the metabolic syndrome and thus evolves in the same context as these metabolic diseases [4]. It is therefore not surprising that recent literature emphasizes a potential role for gut dysbiosis in the pathophysiology of NAFLD. NAFLD encompasses a spectrum of hepatic pathology (i.e., liver phenotypes). Accumulation of triglycerides in hepatocytes (hepatic steatosis) is the most common liver phenotype in NAFLD. Some individuals with hepatic steatosis develop nonalcoholic steatohepatitis (NASH), a more severe type of liver damage characterized by hepatic inflammation and liver cell death. In some individuals with the NASH phenotype, liver regeneration cannot keep pace with the increased rate of hepatocyte death, and liver scarring (fibrosis) ensues. Over time, some of these individuals accumulate sufficient fibrosis to develop cirrhosis. Because cirrhosis dramatically increases the risk for both primary liver cancer and overall liver-related mortality, liver cirrhosis is the NAFLD phenotype that has the worst prognosis. Epidemiologic studies indicate that NAFLD is now the most common cause of liver disease in many countries, including the United States [5]. It is estimated that at least 25% of American adults have some form of NAFLD, with about 6% of the general adult population having NASH and 2%–3% having NAFLD-related cirrhosis.

Clinical spectrum of non-alcoholic fatty liver disease in diabetic and non-diabetic patients

BackgroundWhile non-alcoholic fatty liver disease (NAFLD) has been well characterised in patients with diabetes mellitus (DM), less is known about NAFLD in non-DM patients. We investigated the clinical characteristics of NAFLD patients with and without DM and accuracy of the NAFLD fibrosis score (NFS) in these two NAFLD groups. MethodsClinical, biochemical and histological variables were evaluated in this prospective cross-sectional study of 503 patients with biopsy proven NAFLD. Comparisons between patients with and without DM were analysed. NFS was correlated with liver histology to assess its robustness in patients with and without DM. ResultsThere were 503 biopsy proven NAFLD patients with 48% of the cohort being diabetic. Relative to patients without DM, patients with DM were older (52 vs. 46years, p<0.001), with higher proportion of females (70% vs. 54%, p<0.001), higher BMI (37 vs. 35, p=0.009), higher prevalence of hypertension (73% vs. 44%, p<0.001), higher prevalence of NASH (80.2% vs. 64.4%; p<0.001) and advanced fibrosis (40.3% vs. 17.0%; p<0.001). A considerable amount of patients without DM still had NASH (64%) and advanced fibrosis (17%). The clinical utility of the NFS differed between NAFLD patients with and without DM, with sensitivity to exclude advanced fibrosis being 90% of NAFLD patients with DM but only 58% of patients without DM. ConclusionPatients with DM have more severe NAFLD based on histology. However, NASH and advanced fibrosis also occur in a considerable proportion of NAFLD patients without DM. The lower utility of the NFS in NAFLD patients without DM emphasises the heterogeneous nature of the NAFLD phenotype.

Abstract 014: Brain Endoplasmic Reticulum Stress Mediates the Development of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD), characterized by an accumulation of liver lipids without excess alcohol consumption, is a major risk factor for the development of hypertension and Type-II diabetes. Liver endoplasmic reticulum (ER) stress and activation of the unfolded protein response have been implicated in the development of NAFLD. Brain ER stress has emerged as the basis of a number of chronic diseases, although the role of the central nervous system in mediating NAFLD remains unknown. We hypothesized that brain ER stress contributes to the development of NAFLD. First, male C57Bl/6 mice were instrumented with an intracerebroventricular (ICV) cannula for administration of the chemical ER stress inducer thapsigargin (TG; 1 μg/day; 3 days; n=5) or vehicle control (n=4). Daily short-term induction of ER stress in the brain with TG did not alter body weight (27±1 vs. 27±1 g; vehicle vs. TG; p&gt;0.05), food intake or adiposity, but caused a ~40% increase in liver weight (1.04±0.03 vs. 1.39±0.10 g; vehicle vs. TG; p&lt;0.05). ICV TG also elicited a significant increase in liver triglycerides (36±1 vs. 135±6 mmol; vehicle vs. TG; p&lt;0.05), and real-time PCR analysis revealed upregulation of hepatic gluconeogenic and lipogenic markers in response to short-term brain ER stress (e.g. Pepck 2.45±0.24 fold vehicle; p&lt;0.05). Second, male C57Bl/6 mice were fed high fat diet (HFD, 60% fat, n=8), a model that causes NAFLD and brain ER stress, or remained on normal chow (5% fat, n=6) for 20 weeks. ICV cannula were then implanted for delivery of the chemical ER chaperone TUDCA (5 μg/day) or vehicle control. Inhibition of brain ER stress with ICV TUDCA over 3 days rescued HFD-induced hepatomegaly (2.2±0.2 vs. 1.5±0.1 g; HFD vehicle vs. HFD TUDCA; p&lt;0.05) and reduced obesity-induced liver triglyceride accumulation (365±44 vs. 127±36 mmol; HFD vehicle vs. HFD TUDCA; p&lt;0.05), independent of changes in body weight, food intake or adiposity. These data demonstrate that induction of brain ER stress caused a NAFLD phenotype, whereas inhibition of chronic HFD-induced brain ER stress reduced hepatomegaly and hepatic steatosis. Collectively, these findings illustrate a novel role for ER stress in the brain as a contributor to NAFLD. HL63887, HL84207, AHA13POST14410020, K99HL166776

Postnatal overfeeding promotes early onset and exaggeration of high-fat diet-induced nonalcoholic fatty liver disease through disordered hepatic lipid metabolism in rats

Exposure to overnutrition in critical or sensitive developmental periods may increase the risk of developing obesity and metabolic syndrome in adults. Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome, but the relationship among postnatal nutrition, lipid metabolism, and NAFLD progression during development remains poorly understood. Here we investigated in a rat model whether postnatal overfeeding increases susceptibility to NAFLD in response to a high-fat diet. Litters from Sprague-Dawley dams were culled to three (small litters) or ten (normal litters) pups and then weaned onto a standard or high-fat diet at postnatal day 21 to generate normal-litter, small-litter, normal-litter/high-fat, and small-litter/high-fat groups. At age 16weeks, the small-litter and both high-fat groups showed obesity, dyslipidemia, and insulin resistance. Hepatic disorders appeared earlier in the small-litter/high-fat rats with greater liver mass gain and higher hepatic triglycerides and steatosis score versus normal-litter/high-fat rats. Hepatic acetyl-CoA carboxylase activity and mRNA expression were increased in small-litter rats and aggravated in small-litter/high-fat rats but not in normal-litter/high-fat rats. The high expression in small-litter/high-fat rats coincided with high sterol regulatory element-binding protein-1c mRNA and protein expression. However, mRNA expression of enzymes involved in hepatic fatty acid oxidation (carnitine palmitoyltransferase 1) and output (microsomal triglyceride transfer protein) was decreased under a high-fat diet regardless of litter size. In conclusion, overfeeding related to small-litter rearing during lactation contributes to the NAFLD phenotype when combined with a high-fat diet, possibly through up-regulated hepatic lipogenesis.

Multi-SNP Analysis of GWAS Data Identifies Pathways Associated with Nonalcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease; the histological spectrum of which ranges from steatosis to steatohepatitis. Nonalcoholic steatohepatitis (NASH) often leads to cirrhosis and development of hepatocellular carcinoma. To better understand pathogenesis of NAFLD, we performed the pathway of distinction analysis (PoDA) on a genome-wide association study dataset of 250 non-Hispanic white female adult patients with NAFLD, who were enrolled in the NASH Clinical Research Network (CRN) Database Study, to investigate whether biologic process variation measured through genomic variation of genes within these pathways was related to the development of steatohepatitis or cirrhosis. Pathways such as Recycling of eIF2:GDP, biosynthesis of steroids, Terpenoid biosynthesis and Cholesterol biosynthesis were found to be significantly associated with NASH. SNP variants in Terpenoid synthesis, Cholesterol biosynthesis and biosynthesis of steroids were associated with lobular inflammation and cytologic ballooning while those in Terpenoid synthesis were also associated with fibrosis and cirrhosis. These were also related to the NAFLD activity score (NAS) which is derived from the histological severity of steatosis, inflammation and ballooning degeneration. Eukaryotic protein translation and recycling of eIF2:GDP related SNP variants were associated with ballooning, steatohepatitis and cirrhosis. Il2 signaling events mediated by PI3K, Mitotic metaphase/anaphase transition, and Prostanoid ligand receptors were also significantly associated with cirrhosis. Taken together, the results provide evidence for additional ways, beyond the effects of single SNPs, by which genetic factors might contribute to the susceptibility to develop a particular phenotype of NAFLD and then progress to cirrhosis. Further studies are warranted to explain potential important genetic roles of these biological processes in NAFLD.

When GLP-1 hits the liver: a novel approach for insulin resistance and NASH

nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum ranging from simple steatosis to steatohepatitis (NASH), increasing fibrosis and eventually, cirrhosis ([22][1]). Importantly, NASH accompanied by fibrosis and severe inflammation is the most relevant predictor for disease progression

OP06 Maternal obesity programs offspring innate immune dysregulation in non-alcoholic fatty liver disease

IntroductionObesity induced, non-alcoholic fatty liver disease (NAFLD), is the major cause of chronic liver dysfunction. In tandem, obesity and NAFLD rates in reproductive age women are rising. We have previously...