Features Of Fatty Liver Disease Research Articles

Association between blood chromium and hepatic steatosis assessed by liver ultrasound transient elastography: National Health and Nutrition Examination Survey 2017-2020.

Hepatic steatosis is a significant pathological feature of fatty liver disease (FLD) which is widely spread with no effective treatment available. Previous studies suggest that chromium (Cr) intake reduces lipid deposition in the liver in animals. However, the connection between blood Cr and hepatic steatosis among humans remains inconclusive. Using the data from the National Health and Nutrition Examination Survey (NHANES) 2017-2020, we performed a cross-sectional analysis, including 4,926 participants. The controlled attenuation parameter (CAP) measured by the vibration controlled transient elastography (VCTE) was used to evaluate the degree of liver steatosis. Weighted univariate regression, multivariate linear regression, smooth fitting curves and subgroup analysis were used. In addition, we carried out trend tests, multiple interpolations, and interaction analyses to conduct sensitivity analyses. After adjusting with various covariables, multivariate linear regression analysis demonstrated a significant negative correlation between blood Cr and CAP [β (95% CI) = -5.62 (-11.02, -0.21)]. The negative correlation between blood Cr and CAP was more significant in the males, 50-59 years, overweight, hypercholesterolemia, HDL-C ≥ 65 mg/dL, HbA1c (5.70-6.10 %), HOMA-IR (0.12-2.76), total bilirubin (0.30-0.40 mg/dL), ever alcohol consumption subjects. Of note, the relationships between blood Cr and CAP followed a U-shaped curve in the smokers and non-smokers, with blood Cr thresholds of 0.48, 0.69 μg/L, respectively. There is an independently negative correlation between blood Cr and hepatic steatosis in American. Our study provides clinical researchers with a new insight into the prospective prevention of hepatic steatosis.

Analysis of non-alcoholic fatty liver disease differences from metabolic dysfunction-associated fatty liver disease based on clinical features

Objective: To explore the clinical features of fatty liver disease (FLD) from non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated fatty liver disease (MASLD), so as to elucidate its clinical application value under three renames. Methods: Patients who were hospitalized in the Department of Hepatology, Hospital of Traditional Chinese Medicine Affiliated to Xinjiang Medical University, from January 2020 to September 2023 and met the diagnosis of NAFLD, metabolic-associated fatty liver disease (MAFLD), or MASLD were selected as the research subjects. The clinical indicators differences among the three groups of patients were compared, mainly including general information (age, gender, body mass index, past history, etc.), serological indicators (liver and kidney function, blood lipids, blood sugar, coagulation function, etc.), non-invasive liver fibrosis indicators, fat attenuation parameters, etc. Measurement data were analyzed using ANOVA and the rank sum test, while count data were analyzed using the χ(2) test. Results: NAFLD, MAFLD, and MASLD prevalence rates among 536 cases were 64.0%, 93.7%, and 100%, respectively. 318 cases (59.3%) met the three fatty liver names at the same time among them. Male population proportions in NAFLD, MAFLD, and MASLD were 30.9%, 55.8%, and 53.9%, respectively. The alcohol consumption history proportion was 0, 36.7%, and 36.0%, respectively. The smoking history proportion was 7.0%, 31.9%, and 30.6%, respectively. The body mass index was (27.66 ± 3.97), (28.33 ± 3.63), and (27.90 ± 3.89) kg/m(2), respectively. The γ-glutamyltransferase levels were 26.6 (18.0, 47.0) U/L, 31.0 (20.0, 53.0) U/L, and 30.8 (19.8, 30.8) U/L, respectively. The high-density lipoprotein cholesterol levels were 1.07 (0.90, 1.23) mmol/L, 1.02 (0.86, 1.19) mmol/L, and 1.03 (0.87,1.21) mmol/L, respectively. Sequentially measured uric acid was (322.98 ± 84.51) μmol/L, (346.57 ± 89.49) μmol/L, and (344.89 ±89.67) μmol/L, respectively. Sequentially measured creatinine was 69.6 (62.9, 79.0) μmol/L, 73.0 (65.0, 83.5) μmol/L, and 73.0 (65.0, 83.0) μmol/L, respectively. The sequential analysis of obesity proportion was 74.3%, 81.7%, and 76.5%, respectively, with statistically significant differences (P<0.05). Conclusion: Compared with the NAFLD population, the MAFLD and MASLD populations were predominantly male, obese, and had a history of smoking and drinking. The levels of γ-glutamyltransferase, uric acid, and creatinine were slightly higher, while the levels of high-density lipoprotein cholesterol were lower. MASLD appeared in NAFLD and MAFLD on the basis of inheritance and progression, emphasizing once again the important role of metabolic factors in a fatty liver.

Chronic kidney disease in a murine model of non-alcoholic steatohepatitis (NASH)

Clinical studies suggest that non-alcoholic steatohepatitis (NASH) is an independent risk factor for chronic kidney disease (CKD), but causality and mechanisms linking these two major diseases are lacking. To assess whether NASH can induce CKD, we have characterized kidney function, histological features, transcriptomic and lipidomic profiles in a well-validated murine NASH model. Mice with NASH progressively developed significant podocyte foot process effacement, proteinuria, glomerulosclerosis, tubular epithelial cell injury, lipid accumulation, and interstitial fibrosis. The progression of kidney fibrosis paralleled the severity of the histologic NASH-activity score. Significantly, we confirmed the causal link between NASH and CKD by orthotopic liver transplantation, which attenuated proteinuria, kidney dysfunction, and fibrosis compared with control sham operated mice. Transcriptomic analysis of mouse kidney cortices revealed differentially expressed genes that were highly enriched in mitochondrial dysfunction, lipid metabolic process, and insulin signaling pathways in NASH-induced CKD. Lipidomic analysis of kidney cortices further revealed that phospholipids and sphingolipids were the most significantly changed lipid species. Notably, we found similar kidney histological changes in human NASH and CKD. Thus, our results confirm a causative role of NASH in the development of CKD, reveal potential pathophysiologic mechanisms of NASH-induced kidney injury, and established a valuable model to study the pathogenesis of NASH-associated CKD. This is an important feature of fatty liver disease that has been largely overlooked but has clinical and prognostic importance.

Self-assembling polymer-based short chain fatty acid prodrugs ameliorate non-alcoholic steatohepatitis and liver fibrosis

With the preponderance of a high-calorie diet and sedentary lifestyle, the prevalence of non-alcoholic steatohepatitis (NASH), a state of abnormally elevated lipid accumulation in the liver with chronic inflammation, is increasing at an alarming rate worldwide. Hence, cost-effective therapeutic interventions are required to manage this disease at an early stage. Numerous reports have suggested a link between gut microbial dysbiosis, particularly a decrease in the abundance of short-chain fatty acids (SCFA)-producing microbiota and NASH pathogenesis. Considering these low molecular weight (LMW) SCFAs such as acetic, propionic, and butyric acids have been used to inhibit hepatic steatosis in mouse models. However, the poor pharmacokinetic (PK) profile of SCFAs, caused due to their LMW, renders them therapeutically ineffective. Thus, to improve the PK characteristic-based therapeutic efficacy of LMW SCFAs, we designed SCFA-based prodrugs that possess self-assembling characteristics in aqueous media. The designed SCFA prodrugs consist of enzyme-metabolizable amphiphilic block copolymers, [poly(ethylene glycol)-b-poly(vinyl ester)s] conjugated to propionic acid (PA) or butyric acid (BA) by an ester linkage, which self-assemble into stable nanosized micelles several tens of nanometers in diameter (NanoPA and NanoBA). Via pharmacological analysis, we confirmed that, after oral administration, LMW BA decreased to a physiological level within 24 h in the liver, whereas BA liberated from NanoBA was observed until 72 h post-administration, implying a sustained release profile. Here, we evaluated the therapeutic efficacy of NanoSCFA in a choline-deficient, L-amino acid-defined high-fat diet (CDAHFD)-induced NASH and liver fibrosis mouse model by ad libitum drinking. NanoSCFA, particularly NanoBA, exhibited the remarkable potential to ameliorate the phenotypic features of fatty liver disease by reducing hepatic lipogenesis and fibrosis, with negligible adverse effects. In contrast, conventional LMW SCFAs failed to prevent the pathogenesis of fatty liver disease, which plausibly can be explained by their rapid clearance and discernible adverse effects. Mechanistic studies revealed that NanoBA restored the nuclear expression of PPARα, a transcriptional factor regulating mitochondrial fatty acid oxidation, in the periportal hepatocytes and decreased the CPT1A expression level in the hepatic tissues, reflecting the therapeutic effects of NanoBA. Taken together, we confirmed that our NanoSCFA potentially improved the PK properties of SCFAs, and it consequently alleviated NASH symptoms and fibrotic liver compared to LMW SCFAs. Our study establishes NanoSCFA as a suitable nano-assembled prodrug for NASH treatment.

Regulation of Progressive Liver Disease by Mitochondrial Carboxylate Transport

Mitochondrial transporters link TCA cycle and cytosolic metabolism. Mitochondrial pyruvate import and citrate export are two especially important steps for metabolic regulation. Pyruvate is imported into mitochondria by the mitochondrial pyruvate carrier (MPC), whereas citrate is exported by the mitochondrial citrate carrier (CIC). During fatty liver disease and T2D, liver MPC expression increases and facilitates excessive gluconeogenesis driving chronic hyperglycemia. Liver MPC disruption attenuates hyperglycemia and decreases liver inflammation. Sustained MPC disruption provides long-term protection from hyperglycemia without apparent liver damage. Furthermore, MPC disruption markedly decreases oxidative stress-induced hepatocellular carcinoma, a highly lethal cancer for which fatty liver disease and fibrosis are a major risk factors. The mechanisms by which MPC disruption provides metabolic projection are not completely understood. One potential mechanism is that MPC disruption in-turn decreases mitochondrial citrate export. Cytosolic citrate stimulates increased gluconeogenesis and de novo lipogenesis, two features of fatty liver disease and T2D. Thus, CIC export of citrate derived from MPC-imported pyruvate could mediate these processes. To test the role of the CIC in fatty liver disease, we generated liver-specific CIC knockout mice. Liver CIC disruption markedly decreased de novo lipogenesis measured by deuterated water into lipids. To examine how altered transcriptional programming might contribute to decreased CIC LivKO lipogenesis, we analyzed WT and CIC LivKO livers by RNAseq and qPCR. Numerous genes involved in lipoprotein and fatty acid uptake were upregulated in CIC LivKO livers, including Acly and Fasn, suggesting transcriptional counter regulation for impaired lipogenesis. CIC disruption protected from glucose intolerance after Western diet feeding but did not change insulin tolerance. To understand this selective effect on glucose tolerance, we traced liver 13C-glucose metabolism in vivo. Mass spectrometry analysis of liver extracts showed that CIC disruption increased 13C enrichment into pyruvate and TCA cycle intermediates, consistent with disinhibited glycolysis and decreased mitochondrial citrate export. Together, these data provide evidence for an MPC-CIC axis as key mediator of fatty liver disease.

Microcirculatory changes in the liver of patients with refractory ascites and their relationship with diabetes and alcohol.

The determinants of refractory ascites have not been fully characterized. The aims of this study were to assess liver histopathological alterations associated with refractory ascites and their relationship with comorbidities. Consecutive patients with cirrhosis who underwent liver transplantation were retrospectively included. Patients' characteristics at the time of listing were analysed. The native livers were reviewed and lesions associated with refractory ascites were examined. Out of the 89 patients included, 30 had refractory ascites and 59 did not (including 35 without ascites and 24 with diuretic-sensitive ascites). Patients with and without refractory ascites had a similar amount of fibrous tissue and features of fatty liver disease. By contrast, microvascular changes, namely sinusoidal dilatation (P < 0.001), diffuse perisinusoidal fibrosis (P = 0.001), hepatic venous thromboses (P = 0.004) and vascular proliferation (P = 0.01) were more frequently observed in the livers of patients with refractory ascites. Diabetes (57% vs. 31%, P = 0.02) and alcohol as a causal factor for cirrhosis (80% vs. 42%, P = 0.001) were more frequent in patients with refractory ascites than in those without. By multivariate analysis, refractory ascites was independently associated with diabetes mellitus [odds ratio (OR) (95% confidence interval, CI) 6.15 (1.47-25.71); P = 0.01], alcohol as a causal factor for cirrhosis [OR (95% CI) 4.63 (1.07-20.02); P = 0.04], higher Model For End Stage Liver Diseases [OR (95% CI) 1.21 (1.05-1.38); P = 0.008] and lower serum sodium [OR (95% CI) 0.87 (0.78-0.98); P = 0.03]. Liver microcirculatory changes are associated with refractory ascites. Diabetes and alcohol may explain refractory ascites by causing microangiopathy.

Dietary Wheat Amylase Trypsin Inhibitors Impact Alzheimer's Disease Pathology in 5xFAD Model Mice.

Wheat amylase trypsin inhibitors (ATIs) represent a common dietary protein component of gluten-containing cereals (wheat, rye, and barley). They act as toll-like receptor 4 ligands, and are largely resistant to intestinal proteases, eliciting a mild inflammatory response within the intestine after oral ingestion. Importantly, nutritional ATIs exacerbated inflammatory bowel disease and features of fatty liver disease and the metabolic syndrome in mice. For Alzheimer’s disease (AD), both inflammation and altered insulin resistance are major contributing factors, impacting onset as well as progression of this devastating brain disorder in patients. In this study, we evaluated the impact of dietary ATIs on a well-known rodent model of AD (5xFAD). We assessed metabolic, behavioral, inflammatory, and microbial changes in mice consuming different dietary regimes with and without ATIs, consumed ad libitum for eight weeks. We demonstrate that ATIs, with or without a gluten matrix, had an impact on the metabolism and gut microbiota of 5xFAD mice, aggravating pathological hallmarks of AD. If these findings can be translated to patients, an ATI-depleted diet might offer an alternative therapeutic option for AD and warrants clinical intervention studies.

The offspring from rats fed a fatty diet display impairments in the activation of liver peroxisome proliferator activated receptor alpha and features of fatty liver disease

Maternal obesity programs liver derangements similar to those of NAFLD. Our main goal was to evaluate whether these liver anomalies were related to aberrant PPARα function. Obesity was induced in female Albino-Wistar rats by a fatty diet (FD rats). Several parameters related to NAFLD were evaluated in both plasma and livers from fetuses of 21 days of gestation and 140-day-old offspring. FD fetuses and offspring developed increased levels of AST and ALT, signs of inflammation and oxidative and nitrative stress-related damage. FD offspring showed dysregulation of Plin2, CD36, Cyp4A, Aco, Cpt-1, Hadha and Acaa2 mRNA levels, genes involved in lipid metabolism and no catabolic effect of the PPARα agonist clofibrate. These results suggest that the FD offspring is prone to develop fatty liver, a susceptibility that can be linked to PPARα dysfunction, and that this could in turn be related to the liver impairments programmed by maternal obesity.

Chemokine (C-C motif) ligand 2 gene ablation protects low-density lipoprotein and paraoxonase-1 double deficient mice from liver injury, oxidative stress and inflammation

The risk of non-alcoholic fatty liver disease increases with obesity. Vulnerability to oxidative stress and/or inflammation represents a crucial step in non-alcoholic fatty liver disease progression through abnormal metabolic responses. In this study, we investigated the role of CCL2 gene ablation in mice that were double deficient in low density lipoprotein receptor and in paraoxonase-1. Mass spectrometry methods were used to assess the liver metabolic response in mice fed either regular chow or a high-fat diet. Dietary fat caused liver steatosis, oxidative stress and the accumulation of pro-inflammatory macrophages in the livers of double deficient mice. We observed alterations in energy metabolism-related pathways and in metabolites associated with the methionine cycle and the glutathione reduction pathway. This metabolic response was associated with impaired autophagy. Conversely, when we established CCL2 deficiency, histologic features of fatty liver disease were abrogated, hepatic liver oxidative stress decreased, and anti-inflammatory macrophage marker expression levels increased. These changes were associated with the normalization of metabolic disturbances and increased lysosome-associated membrane protein 2, expression, which suggests enhanced chaperone-mediated autophagy. This study demonstrates that CCL2 is a key molecule for the development of metabolic and histological alterations in the liver of mice sensitive to the development of hyperlipidemia and hepatic steatosis, a finding with potential to identify new therapeutic targets in liver diseases.

Meloxicam increases epidermal growth factor receptor expression improving survival after hepatic resection in diet-induced obese mice

BackgroundPatients with fatty liver have delayed regenerative responses, increased hepatocellular injury, and increased risk for perioperative mortality. Currently, no clinical therapy exists to prevent liver failure or improve regeneration in patients with fatty liver. Previously we demonstrated that obese mice have markedly reduced levels of epidermal growth factor receptor in liver. We sought to identify pharmacologic agents to increase epidermal growth factor receptor expression to improve hepatic regeneration in the setting of fatty liver resection. MethodsLean (20% calories from fat) and diet-induced obese mice (60% calories from fat) were subjected to 70% or 80% hepatectomy. ResultsUsing the BaseSpace Correlation Engine of deposited gene arrays we identified agents that increased hepatic epidermal growth factor receptor. Meloxicam was identified as inducing epidermal growth factor receptor expression across species. Meloxicam improved hepatic steatosis in diet-induced obese mice both grossly and histologically. Immunohistochemistry and Western blot analysis demonstrated that meloxicam pretreatment of diet-induced obese mice dramatically increased epidermal growth factor receptor protein expression in hepatocytes. After 70% hepatectomy, meloxicam pretreatment ameliorated liver injury and significantly accelerated mitotic rates of hepatocytes in obese mice. Recovery of liver mass was accelerated in obese mice pretreated with meloxicam (by 26% at 24 hours and 38% at 48 hours, respectively). After 80% hepatectomy, survival was dramatically increased with meloxicam treatment. ConclusionLow epidermal growth factor receptor expression is a common feature of fatty liver disease. Meloxicam restores epidermal growth factor receptor expression in steatotic hepatocytes. Meloxicam pretreatment may be applied to improve outcome after fatty liver resection or transplantation with steatotic graft.

Nonalcoholic fatty liver disease in spinal and bulbar muscular atrophy.

Objective:To determine the prevalence and features of fatty liver disease in spinal and bulbar muscular atrophy (SBMA).Methods:Two groups of participants with SBMA were evaluated. In the first group, 22 participants with SBMA underwent laboratory analysis and liver imaging. In the second group, 14 participants with SBMA were compared to 13 female carriers and 23 controls. Liver biopsies were done in 4 participants with SBMA.Results:Evidence of fatty liver disease was detected by magnetic resonance spectroscopy in all participants with SBMA in the first group, with an average dome intrahepatic triacylglycerol of 27% (range 6%–66%, ref ≤5.5%). Liver dome magnetic resonance spectroscopy measurements were significantly increased in participants with SBMA in the second group relative to age- and sex-matched controls, with average disease and male control measurements of 17% and 3%, respectively. Liver biopsies were consistent with simple steatosis in 2 participants and nonalcoholic steatohepatitis in 2 others.Conclusions:We observed evidence of nonalcoholic liver disease in nearly all of the participants with SBMA evaluated. These observations expand the phenotypic spectrum of the disease and provide a potential biomarker that can be monitored in future studies.

Dietary Inflammatory Index and liver status in subjects with different adiposity levels within the PREDIMED trial

To assess the possible association between a validated Dietary Inflammatory Index (DII) and specific dietary components with suitable non-invasive markers of liver status in overweight and obese subjects within the PREDIMED study. A cross-sectional study encompassing 794 randomized overweight and obese participants (mean±SD age: 67.0±5.0y, 55% females) from the PREDIMED (PREvención con DIeta MEDiterránea) trial was conducted. DII is a validated tool evaluating the effect of diet on six inflammatory biomarkers (IL-1b, IL-4, IL-6, IL-10, TNF-α and C-reactive protein). Furthermore, a validated 137-item food-frequency-questionnaire was used to obtain the information about the food intake. In addition, anthropometric measurements and several non-invasive markers of liver status were assessed and the Fatty Liver Index (FLI) score was calculated. A higher DII and lower adherence to Mediterranean diet (MeDiet) were associated with a higher degree of liver damage (FLI>60) in obese as compared to overweight participants. Furthermore, the DII score was positively associated with relevant non-invasive liver markers (ALT, AST, GGT and FLI) and directly affected FLI values. Interestingly, a positive correlation was observed between liver damage (>50th percentile FLI) and nutrients and foods linked to a pro-inflammatory dietary pattern. This study reinforced the concept that obesity is associated with liver damage and revealed that the consumption of a pro-inflammatory dietary pattern might contribute to obesity and fatty liver disease features. These data suggest that a well-designed precision diet including putative anti-inflammatory components could specifically prevent and ameliorate non-alcoholic fatty liver manifestations in addition to obesity.

Vitamin E effects on paediatric non-alcoholic fatty liver disease - mini review.

Abstract Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease among children. One of the features of fatty liver disease is high level of serum aminotransferases, which indicates liver cells damage. Antioxidants, reduce the effect of oxidant chemicals, which are produced in liver cells during the disease process. It has been suggested that vitamin E may have a therapeutic effect on fatty liver. The results of the research about the effects of vitamin E in fatty liver disease are controversial. This review will discuss the most updated information on the role and effects of vitamin E on NAFLD.

Susceptibility of Different Mouse Wild Type Strains to Develop Diet-Induced NAFLD/AFLD-Associated Liver Disease.

Although non-alcoholic and alcoholic fatty liver disease have been intensively studied, concerning pathophysiological mechanisms are still incompletely understood. This may be due to the use of different animal models and resulting model-associated variation. Therefore, this study aimed to compare three frequently used wild type mouse strains in their susceptibility to develop diet-induced features of non-alcoholic/alcoholic fatty liver disease. Fatty liver disease associated clinical, biochemical, and histological features in C57BL/6, CD-1, and 129Sv WT mice were induced by (i) high-fat diet feeding, (ii) ethanol feeding only, and (iii) the combination of high-fat diet and ethanol feeding. Hepatic and subcutaneous adipose lipid profiles were compared in CD-1 and 129Sv mice. Additionally hepatic fatty acid composition was determined in 129Sv mice. In C57BL/6 mice dietary regimens resulted in heterogeneous hepatic responses, ranging from pronounced steatosis and inflammation to a lack of any features of fatty liver disease. Liver-related serum biochemistry showed high deviations within the regimen groups. CD-1 mice did not exhibit significant changes in metabolic and liver markers and developed no significant steatosis or inflammation as a response to dietary regimens. Although 129Sv mice showed no weight gain, this strain achieved most consistent features of fatty liver disease, apparent from concentration alterations of liver-related serum biochemistry as well as moderate steatosis and inflammation as a result of all dietary regimens. Furthermore, the hepatic lipid profile as well as the fatty acid composition of 129Sv mice were considerably altered, upon feeding the different dietary regimens. Accordingly, diet-induced non-alcoholic/alcoholic fatty liver disease is most consistently promoted in 129Sv mice compared to C57BL/6 and CD-1 mice. As a conclusion, this study demonstrates the importance of genetic background of used mouse strains for modeling diet-induced non-alcoholic/alcoholic fatty liver disease.

Effect of plant‐based polyunsaturated fatty acids on characteristics of fatty liver disease in laying hens (829.27)

Non‐alcoholic fatty liver disease (NAFLD) and fatty liver hemorrhagic syndrome (FLHS) are common problems related to human and poultry health. Omega‐3 polyunsaturated fatty acids (n‐3 PUFA) are known to modify liver disease development and progression. Flaxseed is the most commonly consumed plant‐based source of n‐3 PUFA, but it remains unclear how different components of the flaxseed food matrix affects characteristics of liver disease. The objective of this study was to determine the effect of feeding different plant‐based sources of PUFA on the development of liver disease in laying hens. Leghorn laying hens aged 1 yr were provided high‐fat (23 en%) diets supplemented with differing sources of fatty acids‐‐corn (CORN), soybean (SOY), and flaxseed (FXO) oils. Defatted (DFM) and whole flaxseed (WFX) meal were provided to additional groups in order to elucidate the components of the flaxseed whole food matrix account for different outcomes. Plasma and tissues were collected and analyzed for metabolic and morphologic parameters, histological grading, and fatty acid profiles. Results indicate WFX supplementation was associated with decreased body weight (p&lt; 0.05) compared to all other groups. All treatment groups displayed significant steatosis, with WFX showing reduced severity compared to CORN, SOY, and DFM (p&lt; 0.05). No treatment consistently resulted in advanced liver disease characterized by hepatocellular injury or inflammation. Taken together, our data suggest flaxseed based diets modestly ameliorate characteristics of fatty liver disease in lay hens, and that flaxseed is most effective when consumed as part of its whole food matrix.

Lipid Metabolism, Oxidative Stress and Cell Death Are Regulated by PKC Delta in a Dietary Model of Nonalcoholic Steatohepatitis

Steatosis, oxidative stress, and apoptosis underlie the development of nonalcoholic steatohepatitis (NASH). Protein kinase C delta (PKCδ) has been implicated in fatty liver disease and is activated in the methionine and choline-deficient (MCD) diet model of NASH, yet its pathophysiological importance towards steatohepatitis progression is uncertain. We therefore addressed the role of PKCδ in the development of steatosis, inflammation, oxidative stress, apoptosis, and fibrosis in an animal model of NASH. We fed PKCδ−/− mice and wildtype littermates a control or MCD diet. PKCδ−/− primary hepatocytes were used to evaluate the direct effects of fatty acids on hepatocyte lipid metabolism gene expression. A reduction in hepatic steatosis and triglyceride levels were observed between wildtype and PKCδ−/− mice fed the MCD diet. The hepatic expression of key regulators of β-oxidation and plasma triglyceride metabolism was significantly reduced in PKCδ−/− mice and changes in serum triglyceride were blocked in PKCδ−/− mice. MCD diet-induced hepatic oxidative stress and hepatocyte apoptosis were reduced in PKCδ−/− mice. MCD diet-induced NADPH oxidase activity and p47phox membrane translocation were blunted and blocked, respectively, in PKCδ−/− mice. Expression of pro-apoptotic genes and caspase 3 and 9 cleavage in the liver of MCD diet fed PKCδ−/− mice were blunted and blocked, respectively. Surprisingly, no differences in MCD diet-induced fibrosis or pro-fibrotic gene expression were observed in 8 week MCD diet fed PKCδ−/− mice. Our results suggest that PKCδ plays a role in key pathological features of fatty liver disease but not ultimately in fibrosis in the MCD diet model of NASH.

Estimation of Fish and ω‐3 Fatty Acid Intake in Pediatric Nonalcoholic Fatty Liver Disease

Fish and ω-3 fatty acids are reported to be beneficial in pediatric nonalcoholic fatty liver disease (NAFLD), but no studies have assessed their relation to histological severity. The objectives of this study were to evaluate the dietary intake of fish and ω-3 fatty acids in children with biopsy-proven NAFLD, and examine their association with serological and histological indicators of disease. This was a cross-sectional analysis of 223 children (6-18 years) who participated in the Treatment of Nonalcoholic Fatty Liver Disease in Children trial or the NAFLD Database study conducted by the Nonalcoholic Steatohepatitis Clinical Research Network. The distribution of fish and ω-3 fatty acid intake was determined from responses to the Block Brief 2000 Food Frequency Questionnaire, and analyzed for associations with serum alanine aminotransferase, histological features of fatty liver disease, and diagnosis of steatohepatitis after adjusting for demographic, anthropometric, and dietary variables. The minority of subjects consumed the recommended 8 ounces of fish per week (22/223 [10%]) and 200 mg of long-chain ω-3 fatty acids per day (12/223 [5%]). Lack of fish and long-chain ω-3 fatty acid intake was associated with greater portal (P = 0.03 and P = 0.10, respectively) and lobular inflammation (P = 0.09 and P = 0.004, respectively) after controlling for potential confounders. Fish and ω-3 fatty acid intake was insufficient in children with NAFLD, which may increase susceptibility to hepatic inflammation. Patients with pediatric NAFLD should be encouraged to consume the recommended amount of fish per week.

Getting the Inside Tract: New Frontiers in Zebrafish Digestive System Biology

Getting the Inside Tract: New Frontiers in Zebrafish Digestive System Biology

Oils rich in α-linolenic acid independently protect against characteristics of fatty liver disease in the Δ6-desaturase null mouse

Alpha-linolenic acid's (ALA) biological activity is poorly understood and primarily associated with its conversion to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Delta-6 desaturase (D6D) initiates the metabolism of linoleic acid (LA) and ALA to arachidonic acid, EPA, and DHA, respectively. In this study, D6D knock-out (D6KO) mice were used to evaluate the effects of ALA-rich oils in preventing hepatic steatosis and inflammation. D6KO and wild-type mice were fed 1 of 4 high-fat (14% w/w) diets: (i) lard (LD, 0% n-3 PUFA), (ii) canola oil + ARASCO (CD, 8% ALA), (iii) flax seed oil + ARASCO (FD, 55% ALA), (iv) menhaden oil (MD, 30% EPA/DHA) for 8 or 20 weeks. Livers of D6KO mice consuming CD and FD were depleted of EPA/DHA, and enriched in ALA. Markers of fat accumulation and inflammation were lowest in the MD-fed mice, at 8 and 20 weeks, regardless of genotype. CD- and FD-fed D6KO groups were found to have lower liver lipid accumulation and lower hepatic inflammation relative to the LD-fed mice at 8 weeks. In conclusion, while MD was the most protective, this study shows that ALA can act independently on risk factors associated with the development of fatty liver disease.

Oils rich in alpha‐linolenic acid independently protect against characteristics of fatty liver disease in the delta‐6‐desaturase null mouse

Non‐alcoholic fatty liver disease (NAFLD) is a growing health concern. The study objective was to use the novel Δ‐6‐desaturase null (D6KO) mouse to determine if α‐linolenic acid (ALA) can independently prevent hepatic steatosis and inflammation. Experimental groups include male wild type (WT) or D6KO mice fed a high fat diet (30% fat) containing either: lard (LD), canola oil (CD,11% ALA), flax oil (FD,50% ALA), or fish oil (MD, n‐3 HUFA) (n=4–7/group) for 8 or 20 weeks. At 8 weeks mean hepatic inflammation scores for D6KO CD and FD groups were intermediate between LD and MD scores, and lower than WT scores. In contrast, D6KO FD and CD groups had higher hepatic steatosis scores relative to WT mice. FD and MD D6KO groups had lower liver lipid mass relative to LD‐fed D6KO mice. Similar trends were seen at 20 weeks. Gas chromatography confirmed the absence of n‐3 HUFA (LD, CD, FD) and of enrichment ALA (CD, FD) in D6KO liver tissue. Results confirm that perturbations in essential fatty acid metabolism lead to the development of fatty liver, and suggest that oils rich in ALA can independently prevent hepatic inflammation. Supported by Canola Council of Canada, NSERC, CFI/ORF to D.Ma and OGS to J. MonteiroGrant Funding Source: Canola Council of Canada, NSERC