Nonalcoholic Fatty liver disease: focus on lipoprotein and lipid deregulation. J Lipids. 2011;2011:783976. [PMID: 21773052 PMCID: PMC3136146 DOI: 10.1155/2011/783976]

NAFLD-associated hepatocellular carcinoma (HCC) - A compelling case for repositioning of existing mTORc1 inhibitors

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) is a growing concern for the high incidence rate of hepatocellular carcinoma (HCC) globally. The progression of NAFLD to HCC is heterogeneous and non-linear, involving intermediate stages of non-alcoholic steatohepatitis (NASH), liver fibrosis, and cirrhosis. There is a high unmet clinical need for appropriate diagnostic, prognostic, and therapeutic options to tackle this emerging epidemic. Unfortunately, at present, there is no validated marker to identify the risk of developing HCC in patients suffering from NAFLD or NASH. Additionally, the current treatment protocols for HCC don't differentiate between viral infection or NAFLD-specific etiology of the HCC and have a limited success rate. The mammalian target of rapamycin complex 1 (mTORc1) is an important protein involved in many vital cellular processes like lipid metabolism, glucose homeostasis, and inflammation. These cellular processes are highly implicated in NAFLD and its progression to severe liver manifestations. Additionally, hyperactivation of mTORc1 is known to promote cell proliferation, which can contribute to the genesis and progression of tumors. Many mTORc1 inhibitors are being evaluated for different types of cancers under various phases of clinical trials. This paper deliberates on the strong pathological implication of the mTORc1 signaling pathway in NAFLD and its progression to NASH and HCC and advocates for a systematic investigation of known mTORc1 inhibitors in suitable pre-clinical models of HCC having NAFLD/NASH-specific etiology.

Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024

Background

This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk.

Methods

This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership.

Results

Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles.

Conclusions

Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.

Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024

BACKGROUND

This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk.

METHODS

This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership.

RESULTS

Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high-density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles.

CONCLUSIONS

Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.

Role of Cardiac Biomarkers in Hepatic Disorders: A Literature Review

Various studies have reported the association between cardiac markers and hepatic disorders. The main objective of this review article was to elucidate the significance of important cardiac indicators such as ischemia-modified albumin, cardiac troponin, cardiac natriuretic peptides, creatine kinase, creatine kinase-MB, lactate dehydrogenase, heart-type fatty acid-binding protein, osteopontin, soluble suppression of tumorigenicity 2, C-reactive protein, and lipoprotein(a) in the development of hepatic disorders. In addition, it highlighted recent notable discoveries and accomplishments in this field and identified areas requiring further investigation, ongoing discussions, and potential avenues for future research. Early identification and control of these cardiac markers might be helpful to control the prevalence of hepatic disorders associated with cardiovascular diseases.

Comprehensive spectroscopic, metabolomic, and proteomic liquid biopsy in the diagnostics of hepatocellular carcinoma

Liquid biopsy is a very topical issue in clinical diagnostics research nowadays. In this study, we explored and compared various analytical approaches to blood plasma analysis. Finally, we proposed a comprehensive procedure, which, thanks to the utilization of multiple analytical techniques, allowed the targeting of various biomolecules in blood plasma reflecting diverse biological processes underlying disease development. The potential of such an approach, combining proteomics, metabolomics, and vibrational spectroscopy along with preceding blood plasma fractionation, was demonstrated on blood plasma samples of patients suffering from hepatocellular carcinoma in cirrhotic terrain (n = 20) and control subjects with liver cirrhosis (n = 20) as well as healthy subjects (n = 20). Most of the applied methods allowed the classification of the samples with an accuracy exceeding 80.0 % and therefore have the potential to be used as a stand-alone method in clinical diagnostics. Moreover, a final panel of 48 variables obtained by a combination of the utilized analytical methods enabled the discrimination of the hepatocellular carcinoma samples from cirrhosis with 94.3 % cross-validated accuracy. Thus, this study, although limited by the cohort size, clearly demonstrated the benefit of the multimethod approach in clinical diagnosis.

Phenotypic and metabolomic characteristics of mouse models of metabolic associated steatohepatitis

BACKGROUND

Metabolic associated steatohepatitis (MASH) is metabolic disease that may progress to cirrhosis and hepatocellular carcinoma. Mouse models of diet-induced MASH, which is characterized by the high levels of fats, sugars, and cholesterol in diets, are commonly used in research. However, mouse models accurately reflecting the progression of MASH in humans remain to be established. Studies have explored the potential use of serological metabolites as biomarkers of MASH severity in relation to human MASH.

METHODS

We performed a comparative analysis of three mouse models of diet-induced MASH in terms of phenotypic and metabolomic characteristics; MASH was induced using different diets: a high-fat diet; a Western diet; and a high-fat, high-cholesterol diet. Liver cirrhosis was diagnosed using standard clinical approaches (e.g., METAVIR score, hyaluronan level, and collagen deposition level). Mouse serum samples were subjected to nuclear magnetic resonance spectroscopy-based metabolomic profiling followed by bioinformatic analyses. Metabolomic analysis of a retrospective cohort of patients with hepatocellular carcinoma was performed; the corresponding cirrhosis scores were also evaluated.

RESULTS

Using clinically relevant quantitative diagnostic methods, the severity of MASH was evaluated. Regarding metabolomics, the number of lipoprotein metabolites increased with both diet and MASH progression. Notably, the levels of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) significantly increased with fibrosis progression. During the development of diet-induced MASH in mice, the strongest upregulation of expression was noted for VLDL receptor. Metabolomic analysis of a retrospective cohort of patients with cirrhosis indicated lipoproteins (e.g., VLDL and LDL) as predominant biomarkers of cirrhosis.

CONCLUSIONS

Our findings provide insight into the pathophysiology and metabolomics of experimental MASH and its relevance to human MASH. The observed upregulation of lipoprotein expression reveals a feedforward mechanism for MASH development that may be targeted for the development of noninvasive diagnosis.

Low-Density Lipoprotein Cholesterol Is Not a Major Determinant of High-Sensitivity C-Reactive Protein Levels in People Without Known Diabetes Mellitus

Background: It has been well established that high-sensitivity C-reactive protein (hs-CRP) is strongly associated with obesity, insulin resistance, high blood pressure, and dyslipidemia. However, the effects of different lipid parameters on hs-CRP levels are less deliberated. The purpose of the study was to compare the relative contribution of triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) to the levels of hs-CRP. Methods: Three hundred seventy-eight subjects without known history of diabetes were recruited for the study. No concomitant antilipid or antidiabetes agents were allowed. Each subject received anthropometric measurements, fasting sampling for lipid profile and hs-CRP, and a 75-gram oral glucose tolerance test for the measurements of insulin resistance (surrogated by insulin sensitivity index ISI0,120). Results: Levels of hs-CRP levels were positively correlated with Log (TG) and negatively correlated with HDL-C in partial correlation after adjustments for confounding variables, but not with LDL-C. The hs-CRP levels in the three groups by tertiles of LDL-C were similar. Subsequently, we found that body mass index (first step), Log (ISI0,120) (second step), and Log (TG) (third step) independently predicted the variance of Log (hs-CRP) in stepwise multiple regression. However, both HDL-C and LDL-C failed to be entered into the models to explain Log (hs-CRP). Conclusions: Our data demonstrated that Log (TG) was a major lipid determinant of hs-CRP levels. The contribution of LDL-C to the levels of hs-CRP might be insignificant.

Design of Next-Generation DGAT2 Inhibitor PF-07202954 with Longer Predicted Half-Life

Diacylglycerol O-acyltransferase 2 (DGAT2) inhibitors have been shown to lower liver triglyceride content and are being explored clinically as a treatment for non-alcoholic steatohepatitis (NASH). This work details efforts to find an extended-half-life DGAT2 inhibitor. A basic moiety was added to a known inhibitor template, and the basicity and lipophilicity were fine-tuned by the addition of electrophilic fluorines. A weakly basic profile was required to find an appropriate balance of potency, clearance, and permeability. This work culminated in the discovery of PF-07202954 (12), a weakly basic DGAT2 inhibitor that has advanced to clinical studies. This molecule displays a higher volume of distribution and longer half-life in preclinical species, in keeping with its physicochemical profile, and lowers liver triglyceride content in a Western-diet-fed rat model.

Rice Bran Extract Suppresses High-Fat Diet-Induced Hyperlipidemia and Hepatosteatosis through Targeting AMPK and STAT3 Signaling

Rice bran, a by-product of rice milling, is abundant in bioactive molecules and is highly recognized for its health-promoting properties, particularly in improving metabolic conditions. Building on this knowledge, we aimed to optimize the extraction conditions to maximize the functional efficacy of rice bran extract (RBE) and further validate its impact on lipid metabolism. We found that the optimized RBE (ORBE) significantly suppressed high-fat diet-induced weight gain, hyperlipidemia, and hepatosteatosis in mouse models. ORBE treatment not only suppressed lipid uptake in vivo, but also reduced lipid accumulation in HepG2 cells. Importantly, we discovered that ORBE administration resulted in activation of AMPK and inhibition of STAT3, which are both crucial players in lipid metabolism in the liver. Collectively, ORBE potentially offers promise as a dietary intervention strategy against hyperlipidemia and hepatosteatosis. This study underlines the value of optimized extraction conditions in enhancing the functional efficacy of rice bran.

Heterozygous midnolin knockout attenuates severity of nonalcoholic fatty liver disease in mice fed a Western-style diet high in fat, cholesterol, and fructose

Although midnolin has been studied for over 20 years, its biological roles in vivo remain largely unknown, especially due to the lack of a functional animal model. Indeed, given our recent discovery that the knockdown of midnolin suppresses liver cancer cell tumorigenicity and that this antitumorigenic effect is associated with modulation of lipid metabolism, we hypothesized that knockout of midnolin in vivo could potentially protect from nonalcoholic fatty liver disease (NAFLD) which has become the most common cause of chronic liver disease in the Western world. Accordingly, in the present study, we have developed and now report on the first functional global midnolin knockout mouse model. Although the overwhelming majority of global homozygous midnolin knockout mice demonstrated embryonic lethality, heterozygous knockout mice were observed to be similar to wild-type mice in their viability and were used to determine the effect of reduced midnolin expression on NAFLD. We found that global heterozygous midnolin knockout attenuated the severity of NAFLD in mice fed a Western-style diet, high in fat, cholesterol, and fructose, and this attenuation in disease was associated with significantly reduced levels of large lipid droplets, hepatic free cholesterol, and serum LDL, with significantly differential gene expression involved in cholesterol/lipid metabolism. Collectively, our results support a role for midnolin in regulating cholesterol/lipid metabolism in the liver. Thus, midnolin may represent a novel therapeutic target for NAFLD. Finally, our observation that midnolin was essential for survival underscores the broad importance of this gene beyond its role in liver biology.NEW & NOTEWORTHY We have developed and now report on the first functional global midnolin knockout mouse model. We found that global heterozygous midnolin knockout attenuated the severity of nonalcoholic fatty liver disease (NAFLD) in mice fed a Western-style diet, high in fat, cholesterol, and fructose, and this attenuation in disease was associated with significantly reduced levels of large lipid droplets, hepatic free cholesterol, and serum LDL, with significantly differential gene expression involved in cholesterol/lipid metabolism.

Triclocarban and triclosan exacerbate high-fat diet-induced hepatic lipid accumulation at environmental related levels: The potential roles of estrogen-related receptors pathways

Triclosan (TCS) and triclocarban (TCC) have become ubiquitous pollutants detected in human body with concentrations up to hundreds of nanomolar levels. Previous studies about the hepatic lipid accumulation induced by TCS and TCC were focused on pollutant itself, which showed weak or no effects. High-fat diet (HFD), as a known environmental factor contributing to lipid metabolism-related disorders, its synergistic action with environmental pollutants deserves concern. The present study aimed to demonstrate the combined effects and potential molecular mechanisms of TCS and TCC with HFD at cellular and animal levels. The in vitro studies showed that TCC and TCS alone had negligible impact on lipid accumulation in HepG2 cells but induced lipid deposition at nanomolar levels when co-exposure with fatty acid. TCC exhibited much higher induction effects than TCS, which was related to their differential regulatory roles in adipogenic-related genes expression. The in vivo studies showed that TCC had little influence on hepatic lipid accumulation in mice fed with normal diet (ND) but could exacerbate the lipid accumulation in mice fed with HFD. Meanwhile, TCC-induced dyslipidemia in mice fed with HFD was more significant than that fed with ND. Therefore, we speculated that TCC might increase the risk of nonalcoholic fatty liver disease (NAFLD) and atherosclerosis in HFD humans. Molecular mechanism studies showed that TCC and TCS could bind to and activate estrogen-related receptor α (ERRα) and ERRγ as well as regulate their expression. TCC had higher activity on ERRα and ERRγ than TCS, which explained partly the differential regulatory roles of two receptors in the lipid accumulation induced by TCC and TCS. This work revealed synergistic effects and molecular mechanisms of TCC and TCS with excessive fatty acid on the hepatic lipid metabolism, which provided a novel insight into the toxic mechanism of pollutants from the perspective of dietary habits.

Non-alcoholic fatty liver disease is not independently associated with Helicobacter pylori in a central European screening cohort

BACKGROUND

The association between Helicobacter pylori (Hp) infection and non-alcoholic fatty liver disease (NAFLD) is subject of a contentious debate. Data mainly stem from Asian cohorts whereas European data are scarce. We, therefore, investigated an Austrian colorectal cancer screening cohort for an association between Hp and NAFLD.

METHODS

In total, 5338 consecutive participants undergoing screening colonoscopy at a single center in Austria were evaluated in this cross-sectional study. The primary risk factor was being Hp negative or positive. The primary endpoint was the presence of NAFLD defined by ultrasound (NAFLD; primary endpoint). Uni- and multivariable logistic regression models were fitted to obtain odds ratios (OR) and 95% confidence intervals (95%CI). Finally, this association was analyzed in a subgroup of 1128 patients in whom NAFLD was diagnosed by transient elastography (TE, secondary endpoint).

RESULTS

NAFLD prevalence defined by ultrasound did not differ between Hp positive (48%) and negative patients (45%, P=0.097). Accordingly, in uni- (OR 1.12 95% CI 0.98-1.29; P=0.098) and multivariable analysis adjusting for different risk factors (aOR 0.96 95%CI 0.82-1.13; P=0.601) no independent association was found. On subgroup analysis, NAFLD diagnosed by TE was more prevalent in the Hp positive compared to the Hp negative group (49% vs. 38%, P=0.004) and these patients also had higher steatosis grades. However, after adjustment for risk factors, no independent association between Hp positivity and NAFLD diagnosed by TE (aOR 1.26 95%CI 0.89-1.78; P=0.194) was confirmed.

CONCLUSIONS

In this Central European cohort, Hp-positivity was not associated with the diagnosis of NAFLD. Although Hp positive patients seem to be more likely to have a concomitant NAFLD diagnosis, this association might rather relate to a cardiometabolic risk phenotype than causality.

Discovery of Ervogastat (PF-06865571): A Potent and Selective Inhibitor of Diacylglycerol Acyltransferase 2 for the Treatment of Non-alcoholic Steatohepatitis

Discovery efforts leading to the identification of ervogastat (PF-06865571), a systemically acting diacylglycerol acyltransferase (DGAT2) inhibitor that has advanced into clinical trials for the treatment of non-alcoholic steatohepatitis (NASH) with liver fibrosis, are described herein. Ervogastat is a first-in-class DGAT2 inhibitor that addressed potential development risks of the prototype liver-targeted DGAT2 inhibitor PF-06427878. Key design elements that culminated in the discovery of ervogastat are (1) replacement of the metabolically labile motif with a 3,5-disubstituted pyridine system, which addressed potential safety risks arising from a cytochrome P450-mediated O-dearylation of PF-06427878 to a reactive quinone metabolite precursor, and (2) modifications of the amide group to a 3-THF group, guided by metabolite identification studies coupled with property-based drug design.

Utility of traditional and non-traditional lipid indicators in the diagnosis of nonalcoholic fatty liver disease in a Japanese population

BACKGROUND

Traditional and non-traditional (TNNT) lipid indicators are known to be closely related to nonalcoholic fatty liver disease (NAFLD). This study's objective was to compare the degree of associations and diagnostic values of TNNT lipid indicators with NAFLD.

METHODS

Participants were 14,251 Japanese adults who undergoing health checkups, and we measured and calculated 11 lipid indicators, including traditional lipid indicators such as high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG), as well as non-traditional lipid indicators such as TC/HDL-C ratio, LDL-C/HDL-C ratio, TG/HDL-C ratio, non-HDL-C, remnant cholesterol (RC), RC/HDL-C ratio and non-HDL-C/HDL-C ratio. The associations between these lipid indicators and NAFLD were assessed using multivariate logistic regression, and the performance of these lipid indicators in identifying NAFLD was analyzed by receiver operating characteristic (ROC) curves.

RESULTS

After rigorous adjustment for potential confounders, multivariate logistic regression showed that all TNNT lipid indicators were independently associated with NAFLD, among which the RC/HDL-C ratio and RC had the strongest association with NAFLD. ROC analysis showed that non-traditional lipid indicators were superior to traditional lipid indicators in identifying NAFLD, especially in young adults and females. It is worth mentioning that the RC/HDL-C ratio was the best lipid indicator for identifying NAFLD with an area under the curve (AUC) of 0.82 and an optimal cut-off value of 0.43; in addition, TG/HDL-C ratio also had a high recognition performance for NAFLD.

CONCLUSION

Overall, in the Japanese population, non-traditional lipid indicators had a higher diagnostic value for NAFLD compared to traditional lipid indicators, and lipid indicators alone had a lower diagnostic value for NAFLD than the ratio of two lipid indicators, with RC/HDL-C and TG/HDL-C being the best lipid indicators for identifying NAFLD.

Chitosan reduces inflammation and protects against oxidative stress in a hyperlipidemic rat model: relevance to nonalcoholic fatty liver disease

BACKGROUND

An altered lipid profile may lead to the development of inflammation and NAFLD (Non-alcoholic fatty liver disease). Although statins have a positive effect on blood lipid levels their long-term use is known to cause adverse effects, in this backdrop there is an interest in natural compounds which may affect lipid metabolism and prevent NAFLD. We have examined the effect of Chitosan on rats subjected to a high-fat diet.

METHODS AND RESULTS

Male Wistar middle aged rats (12-16 months) were treated with high-fat diet orally for two months for creating a NAFLD model. Rats were also supplemented with Chitosan (2% chitosan daily) for 2 months. We assessed the activity of antioxidant enzymes, the histopathological profile of the liver. Inflammatory cytokines and adiponectin levels were also measured in serum. HFD induced significant changes in liver tissue and inflammatory markers (Il-6, TNF- alpha, NF-KB). Chitosan treatment protected rats from HFD induced alterations.

CONCLUSIONS

The findings suggest that Chitosan can effectively improve liver lipid metabolism by normalizing cholesterol, triglyceride, lowering NF-KB expression, and protecting the liver from oxidative stress by improving hepatic function. Chitosan also regulates genes related to lipidemic stress i,e leptin and adiponectin.

The postnatal resolution of developmental toxicity induced by pharmacological diacylglycerol acyltransferase 2 (DGAT2) inhibition during gestation in rats

Ervogastat (PF-06865571) is a small molecule diacylglycerol acyltransferase 2 (DGAT2) inhibitor being developed for the oral treatment of non-alcoholic steatohepatitis (NASH) with liver fibrosis. DGAT2 is a key enzyme in triglyceride synthesis in tissues and in regulating energy metabolism. Fertility and developmental toxicity studies with ervogastat were conducted in female rats and rabbits. There were no effects on female rat fertility or rabbit embryo-fetal development. Administration of ervogastat to pregnant rats during organogenesis reduced fetal weight and caused higher incidences of bent bones in fetuses that were shown to resolve by postnatal day 28 and were therefore considered to be transient variations secondary to developmental delay. Extended dosing in rats through the end of gestation and lactation (pre- and post-natal development study) caused impaired skin development, reduced offspring viability and growth retardation. The spectrum of developmental effects in rats is consistent with the intended pharmacology (altered triglyceride metabolism) and the transient nature of the skeletal findings, along with the late gestational window of sensitivity for the effects on skin barrier development, reduce the concern for potential adverse developmental effects following unintended early gestational exposure to ervogastat in humans where treatment can be discontinued once pregnancy is determined.

Impact of NAFLD and its pharmacotherapy on lipid profile and CVD

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide. Increasing evidence suggests that, in addition to traditional metabolic risk factors such as obesity, hypercholesterolemia, hypertension, diabetes mellitus, and insulin resistance (IR), nonalcoholic fatty liver disease (NAFLD) is an emerging driver of ASCVD via multiple mechanisms, mainly by disrupting lipid metabolism. The lack of pharmaceutical treatment has spurred substantial investment in the research and development of NAFLD drugs. However, many reagents with promising therapeutic potential for NAFLD also have considerable impacts on the circulating lipid profile. In this review, we first summarize the mechanisms linking lipid dysregulation in NAFLD to the progression of ASCVD. Importantly, we highlight the potential risks of/benefits to ASCVD conferred by NAFLD pharmaceutical treatments and discuss potential strategies and next-generation drugs for treating NAFLD without the unwanted side effects.

Identification of the Potential Molecular Mechanisms Linking RUNX1 Activity with Nonalcoholic Fatty Liver Disease, by Means of Systems Biology

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic hepatic disease; nevertheless, no definitive diagnostic method exists yet, apart from invasive liver biopsy, and nor is there a specific approved treatment. Runt-related transcription factor 1 (RUNX1) plays a major role in angiogenesis and inflammation; however, its link with NAFLD is unclear as controversial results have been reported. Thus, the objective of this work was to determine the proteins involved in the molecular mechanisms between RUNX1 and NAFLD, by means of systems biology. First, a mathematical model that simulates NAFLD pathophysiology was generated by analyzing Anaxomics databases and reviewing available scientific literature. Artificial neural networks established NAFLD pathophysiological processes functionally related to RUNX1: hepatic insulin resistance, lipotoxicity, and hepatic injury-liver fibrosis. Our study indicated that RUNX1 might have a high relationship with hepatic injury-liver fibrosis, and a medium relationship with lipotoxicity and insulin resistance motives. Additionally, we found five RUNX1-regulated proteins with a direct involvement in NAFLD motives, which were NFκB1, NFκB2, TNF, ADIPOQ, and IL-6. In conclusion, we suggested a relationship between RUNX1 and NAFLD since RUNX1 seems to regulate NAFLD molecular pathways, posing it as a potential therapeutic target of NAFLD, although more studies in this field are needed.

Mesencephalic astrocyte-derived neurotrophic factor alleviates non-alcoholic steatohepatitis induced by Western diet in mice

Excessive lipid accumulation, inflammation, and fibrosis in the liver are the major characteristics of non-alcoholic steatohepatitis (NASH). Mesencephalic astrocyte-derived neurotrophic factor (MANF) plays an important role in metabolic homeostasis, raising the possibility that it is involved in NASH. Here, we reduced and increased MANF levels in mice in order to explore its influence on hepatic triglyceride homeostasis, inflammation, and fibrosis during NASH progression. The MANF expression was decreased in Western diet-induced NASH mice. In vivo, liver-specific MANF knockout exacerbated hepatic lipid accumulation, inflammation, and fibrosis of mice induced by Western diet, while liver-specific MANF overexpression mitigated these NASH pathogenic features. In vitro, knocking down MANF in primary hepatocyte cultures aggravated hepatic steatosis and inflammation, which MANF overexpression markedly attenuated. Studies in vitro and in vivo suggested that MANF regulated hepatic lipid synthesis by modulating SREBP1 expression. Inhibiting SREBP1 in primary hepatocytes blocked lipid accumulation after MANF knockdown. MANF overexpression reversed LXRs agonist GW3965 induced SREBP1 and LIPIN1 expression. MANF decreased the expression of pro-inflammatory cytokines by inhibiting NF-κB phosphorylation. These results suggest that MANF can protect against NASH by regulating SREBP1 expression and NF-κB signaling.

Hepatoprotection of Probiotics Against Non-Alcoholic Fatty Liver Disease in vivo: A Systematic Review

Probiotic supplements have been increasingly reported for their usefulness in delaying the development and progression of non-alcoholic fatty liver disease (NAFLD). Literature on the impact of probiotics on NAFLD covered various aspects of the disease. This study was undertaken to systematically review in vivo findings on hepatoprotection of probiotics against NAFLD. The literature search was performed through Cochrane, PubMed/MEDLINE, Embase, and Web of Science databases. Interventions of known probiotics in NAFLD-induced animal model with at least one measurable NAFLD-related parameter were included. The data were extracted by all authors independently. Quality assessment was conducted using the Systematic Review Center for Laboratory animal Experimentation (SYRCLE's) Risk of Bias (RoB) tool. P-values of measures were compared inter- and intra-study for each parameter. Forty-four probiotic-based studies of NAFLD-induced rodents were shortlisted. The majority of the studies were presented with low/unclear risk of bias. Probiotics improved the histopathology of NAFLD rodents (primary outcome). Most of the probiotic-supplemented NAFLD rodents were presented with mixed effects on serum liver enzymes but with improved hepatic and serum lipid profiles (including increased serum high-density lipoprotein cholesterol). The findings were generally accompanied by downregulation of hepatic lipogenic, oxidative, and inflammatory signallings. Probiotics were found to modulate gut microbiota composition and its products, and intestinal permeability. Probiotics also resulted in better glycaemic control and reduced liver weight. Altogether, the present qualitative appraisals strongly implied the hepatoprotective potential of probiotics against NAFLD in vivo.

Mitochondrial depletion of glutaredoxin 2 induces metabolic dysfunction-associated fatty liver disease in mice

Glutaredoxin 2 (Grx2) is a glutathione-dependent oxidoreductase that facilitates glutathionylation/de-glutathionylation of target proteins. The main variants of Grx2 are the mitochondrial Grx2a and the cytosolic Grx2c. The aim of this study was to investigate the specific role of mitochondrial Grx2 in vivo using a mitochondrial Grx2 depleted (mGD) mouse model. mGD mice displayed an altered mitochondrial morphology and functioning. Furthermore, the lack of Grx2 in the mitochondrial compartment is responsible for increased blood lipid levels under a normal diet, a metabolic dysfunction-associated fatty liver disease (MAFLD) phenotype and a decreased glycogen storage capacity. In addition, depleting Grx2a leads to an alteration in abundance and in glutathionylation pattern of different mitochondrial enzymes, highlighting the selective role of Grx2 in the regulation of metabolic pathways. Overall, our findings identify the involvement of mitochondrial Grx2a in the regulation of cell metabolism and highlight a previously unknown association between Grx2 and MAFLD.

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Mitochondrial Grx2 depleted (mGD) mice display mitochondrial impairment.

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mGD mice show alterations in lipid metabolism and glycogen storage in the liver.

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Upon Grx2 deficiency the glutathionylation pattern of metabolic enzymes changes

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Mitochondrial Grx2 depletion is associated with MAFLD development

Association of Lipid and Body Mass Index Profile With Chronic Hepatitis C Infection Stratified by Age and Gender

Background

In this study, we aimed to determine the association of lipid and body mass index (BMI) profiles among cases having chronic hepatitis C virus (CHCV) infection.

Methodology

This cross-sectional study was conducted in the outpatient department of a tertiary care hospital. A total of 320 cases of both genders, aged 18 to 60 years, with CHCV infection were enrolled in the study. After obtaining relevant history and conducting a physical examination, the venous blood sample of each patient was taken and sent to the institutional laboratory to analyze serum total cholesterol, serum triglyceride, low-density lipoprotein, and high-density lipoprotein levels. BMI of all the study participants was also noted.

Results

Of the total 320 cases, there were 152 (47.5%) males and 168 (52.5%) females. The overall mean age was 42.92 ± 11.38 years. Most cases [97 (30.3%)] were in the 41 to 50-year age group. Overall, the mean BMI was 27.75 ± 4.59 kg/m². Dyslipidemia was noted in 144 (45.0%) cases. Increasing age and increasing BMI were found to have statistical significance with the presence of dyslipidemia (p < 0.05).

Conclusions

Increasing age and BMI have a significant association with dyslipidemia in patients with CHCV infection. Lipid profile appears to differ among different age and BMI groups.

Design Strategy for a Hydroxide-Triggered pH-Responsive Hydrogel as a Mucoadhesive Barrier to Prevent Metabolism Disorders

Excess nutrient uptake is one of the main factors of complications related to metabolism disorders. Therefore, efforts have emerged to modulate nutrient transport in the intestine. However, current approaches are mainly invasive interventions with various side effects. Here, a pH-responsive hydrogel is formulated by acidifying the hydroxide compounds within sucralfate to allow electrostatic interactions between pectin and aluminum ions. The pH responsiveness relies on the alternation of cations and hydroxide species, providing reversible shifting from a hydrogel to a complex coacervate system. It acts as a transient physical barrier coating to inhibit intestinal absorption and changes the viscosity and barrier function in different parts of the gastrointestinal tract, showing enhanced mucoadhesive properties. The therapeutic hydrogel remarkably lowers the immediate blood glucose response by modulating nutrient contact with bowel mucosa, suggesting potential in treating diabetes. In addition, it significantly reduces weight gain, fat accumulation, and hepatic lipid deposition in rodent models. This study provides a novel strategy for fabricating pH-responsive hydrogels, which may serve as a competent candidate for metabolism disorder management.

Berberine mitigates nonalcoholic hepatic steatosis by downregulating SIRT1-FoxO1-SREBP2 pathway for cholesterol synthesis

OBJECTIVE

To investigate effects of berberine (BBR) on cholesterol synthesis in HepG2 cells with free fatty acid (FFA)-induced steatosis and to explore the underlying mechanisms.

METHODS

A steatosis cell model was induced in HepG2 cell line fed with FFA (0.5 mmol/L, oleic acid:palmitic acid = 2:1), and then treated with three concentrations of BBR; cell viability was assessed with cell counting kit-8 assays. Lipid accumulation in cells was observed through oil red O staining and total cholesterol (TC) content was detected by TC assay. The effects of BBR on cholesterol synthesis mediators were assessed by Western blotting and quantitative polymerase chain reaction. In addition, both silent information regulator 1 (SIRT1) and forkhead box transcription factor O1 (FoxO1) inhibitors were employed for validation.

RESULTS

FFA-induced steatosis was successfully established in HepG2 cells. Lipid accumulation and TC content in BBR groups were significantly lower (P < 0.05, P < 0.01), associated with significantly higher mRNA and protein levels of SIRT1(P < 0.05, P < 0.01), significantly lower sterol regulatory element-binding protein 2 (SREBP2) and 3-hydroxy 3-methylglutaryl-CoA reductase levels (P < 0.05, P < 0.01), as well as higher Acetyl-FoxO1 protein level (P < 0.05, P < 0.01) compared to the FFA only group. Both SIRT1 inhibitor SIRT1-IN-1 and FoxO1 inhibitor AS1842856 blocked the BBR-mediated therapeutic effects. Immunofluorescence showed that the increased SIRT1 expression increased FoxO1 deacetylation, and promoted its nuclear translocation.

CONCLUSION

BBR can mitigate FFA-induced steatosis in HepG2 cells by activating SIRT1-FoxO1-SREBP2 signal pathway. BBR may emerge as a potential drug candidate for treating nonalcoholic hepatic steatosis.

The potential pathophysiological role of altered lipid metabolism and electronegative low-density lipoprotein (LDL) in non-alcoholic fatty liver disease and cardiovascular diseases

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term for a range of conditions caused by a build-up of fat in the liver. It is usually seen in people who are overweight or obese. Increasingly common around the world, this disease is the most common chronic liver disease in the United States, affecting about a quarter of the population. Recently, the designation of NAFLD as 'metabolic dysfunction-associated fatty liver disease' (MAFLD) has been a subject of current debate. In this context, 'insulin resistance' is the underlying common and basic pathophysiological mechanism of metabolic dysfunction due to its association with obesity, type 2 diabetes mellitus (T2DM), metabolic syndrome, dyslipidemia and NAFLD. All these pathological conditions are among the metabolic risk factors for cardiovascular diseases, too. Also, due to the bidirectional causality between NAFLD and cardiovascular diseases, a liver-heart axis is suggested. Therefore, various factors such as insulin resistance as well as systemic inflammation, cytokines, oxidative stress, adipokines, hepatokines, genes and intestinal microbiota have been identified as possible pathogenic factors that play a role in the explanation of the complex NAFLD and cardiovascular risk relationship. Recent data and cumulative evidence show that electronegative low-density lipoprotein [LDL (-)/L5] cholesterol is a promising biomarker for complex organ interactions and diseases associated with liver-heart axis. In this mini review, we focus not only on recent data on NAFLD mechanisms, but also on the potential of the lipid mediator LDL (-)/L5 as a diagnostic and therapeutic target for liver-heart line diseases.

Association of remnant cholesterol with nonalcoholic fatty liver disease: a general population-based study

BACKGROUND

Remnant cholesterol (RC) mediates the progression of coronary artery disease, diabetic complications, hypertension, and chronic kidney disease. Limited information is available on the association of RC with nonalcoholic fatty liver disease (NAFLD). This study aimed to explore whether RC can be used to independently evaluate the risk of NAFLD in the general population and to analyze the predictive value of RC for NAFLD.

METHODS

The study included 14,251 subjects enrolled in a health screening program. NAFLD was diagnosed by ultrasound, and the association of RC with NAFLD was assessed using the receiver operating characteristic (ROC) curve and logistic regression equation.

RESULTS

Subjects with elevated RC had a significantly higher risk of developing NAFLD after fully adjusting for potential confounding factors (OR 1.77 per SD increase, 95% CI 1.64-1.91, P trend< 0.001). There were significant differences in this association among sex, BMI and age stratification. Compared with men, women were facing a higher risk of RC-related NAFLD. Compared with people with normal BMI, overweight and obesity, the risk of RC-related NAFLD was higher in thin people. In different age stratifications, when RC increased, young people had a higher risk of developing NAFLD than other age groups. Additionally, ROC analysis results showed that among all lipid parameters, the AUC of RC was the largest (women: 0.81; men: 0.74), and the best threshold for predicting NAFLD was 0.54 in women and 0.63 in men.

CONCLUSIONS

The results obtained from this study indicate that (1) in the general population, RC is independently associated with NAFLD but not with other risk factors. (2) Compared with traditional lipid parameters, RC has a better predictive ability for NAFLD in men.

Proteome analysis identified proteins associated with mitochondrial function and inflammation activation crucially regulating the pathogenesis of fatty liver disease

Background

Fatty liver disease prevalently occurs in commercial postpartum dairies, resulting in a worldwide high culling rate because of their subsequent limitations of production and reproduction performance.

Results

Fatty liver-specific proteome and acetylome analysis revealed that energy metabolism suppression closely associated with mitochondrial dysfunction and inflammation activation were shown to be remarkable biological processes underlying the development of fatty liver disease, furthermore, acetylation modification of proteins could be one of the main means to modulate these processes. Twenty pivotal genetic factors/genes that differentially expressing and being acetylation modified in liver were identified and proposed to regulate the pathogenesis of fatty liver dairies. These proteins were confirmed to be differentially expressing in individual liver tissue, eight of which being validated via immunohistochemistry assay.

Conclusions

This study provided a comprehensive proteome and acetylome profile of fatty liver of dairy cows, and revealed potential important biological processes and essential regulators in the pathogenesis of fatty liver disease. Expectantly, understanding the molecular mechanisms of the pathogenesis of fatty liver disease in dairies, as an animal model of non-alcoholic fatty liver disease (NAFLD) in human beings, which is a clinico-pathologically defined process associated with metabolic syndrome, could inspire and facilitate the development of efficacious therapeutic drugs on NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07950-2.

Lupinus angustifolius Protein Hydrolysates Reduce Abdominal Adiposity and Ameliorate Metabolic Associated Fatty Liver Disease (MAFLD) in Western Diet Fed-ApoE-/- Mice

Metabolic-associated fatty liver disease (MAFLD) is the most important cause of liver disease worldwide. It is characterized by the accumulation of fat in the liver and is closely associated with abdominal obesity. In addition, oxidative stress and inflammation are significant features involved in MAFLD. Recently, our group demonstrated that lupin protein hydrolysates (LPHs) had lipid lowering, antioxidant, and anti-inflammatory effects. Sixty male mice fed with a Western diet were intragastrically treated with LPHs (or vehicle) for 12 weeks. Liver and adipose tissue lipid accumulation and hepatic inflammatory and oxidant status were evaluated. A significant decrease in steatosis was observed in LPHs-treated mice, which presented a decreased gene expression of CD36 and LDL-R, crucial markers in MAFLD. In addition, LPHs increased the hepatic total antioxidant capacity and reduced the hepatic inflammatory status. Moreover, LPHs-treated mice showed a significant reduction in abdominal adiposity. This is the first study to show that the supplementation with LPHs markedly ameliorates the generation of the steatotic liver caused by the intake of a Western diet and reduces abdominal obesity in ApoE^−/− mice. Future clinical trials should shed light on the effects of LPHs on MAFLD.

The Application of Induced Pluripotent Stem Cells Against Liver Diseases: An Update and a Review

Liver diseases are a major health concern globally, and are associated with poor survival and prognosis of patients. This creates the need for patients to accept the main alternative treatment of liver transplantation to prevent progression to end-stage liver disease. Investigation of the molecular mechanisms underpinning complex liver diseases and their pathology is an emerging goal of stem cell scope. Human induced pluripotent stem cells (hiPSCs) derived from somatic cells are a promising alternative approach to the treatment of liver disease, and a prospective model for studying complex liver diseases. Here, we review hiPSC technology of cell reprogramming and differentiation, and discuss the potential application of hiPSC-derived liver cells, such as hepatocytes and cholangiocytes, in refractory liver-disease modeling and treatment, and drug screening and toxicity testing. We also consider hiPSC safety in clinical applications, based on genomic and epigenetic alterations, tumorigenicity, and immunogenicity.

Lipoprotein Insulin Resistance Index Reflects Liver Fat Content in Patients With Nonalcoholic Fatty Liver Disease

The recently developed lipoprotein insulin resistance index (LP-IR) incorporates lipoprotein particle numbers and sizes and is considered to reflect both hepatic and peripheral IR. As tissue IR is a strong component of nonalcoholic fatty liver disease (NAFLD) pathogenesis, we aimed to assess the degree by which LP-IR associates with hepatic fat content. This was a single-center retrospective analysis of patients with NAFLD. LP-IR, the homeostasis model assessment of insulin resistance (HOMA-IR), and adipose tissue IR (Adipo-IR) were measured simultaneously. Liver fat content was estimated by FibroScan controlled attenuated parameter. Associations were assessed using Spearman's correlation and multivariate linear regression. The study included 61 patients. LP-IR was correlated with HOMA-IR (ρ = 0.30; P = 0.02), typically thought to reflect hepatic IR, but not with Adipo-IR (ρ = 0.15; P = 0.25). Liver fat content was significantly associated with Adipo-IR (ρ = 0.48; P < 0.001), LP-IR (ρ = 0.35; P = 0.005), and to a lesser degree with HOMA-IR (ρ = 0.25; P = 0.051). The association of liver fat with LP-IR was limited to patients without diabetes (ρ = 0.60; P < 0.0001), whereas no association was seen in those with diabetes. In a multivariate model, Adipo-IR, LP-IR, and diabetes were independently associated with liver fat and together explained 35% of the variability in liver fat. Conclusion: LP-IR is a reasonable measure of IR in non-diabetic patients with NAFLD and is associated with hepatic fat content. Although adipose tissue is the major contributor to liver fat, the additional contribution of nonadipose tissues can be easily estimated using LP-IR.

Bioinformatics analysis of differentially expressed proteins in alcoholic fatty liver disease treated with recombinant human cytoglobin

Cytoglobin (Cygb) is a globin molecule that is ubiquitously expressed in all tissues and has a protective role under oxidative stress. It has also been demonstrated to be effective in the treatment of alcoholic fatty liver disease (AFLD). In order to study the molecular mechanisms underlying its beneficial effects for the treatment of alcoholic liver, two‑dimensional electrophoresis and mass spectrometric analysis were performed on serum and liver tissues from an in vivo rat model of AFLD. A total of 26 differentially expressed proteins were identified in the serum and 20 differentially expressed proteins were identified in liver specimens. Using online bioinformatics tools, it was indicated that these differentially expressed proteins were primarily associated with pathways including binding and uptake of ligands by scavenger receptors, response to corticosteroid, plasma lipoprotein remodeling, regulation of complement cascade, hydrogen peroxide catabolic process, as well as response to nutrient and monosaccharide. The present results suggested that recombinant human Cygb exerts its role in the treatment of AFLD primarily through affecting nutrient metabolism, monocarboxylic acid biosynthesis, regulation of glutathione expression, plasma lipoprotein remodeling and removal of metabolic waste from the blood.

Therapeutic Effects of Different Animal Bile Powders on Lipid Metabolism Disorders and Their Composition Analysis

OBJECTIVE

To compare the therapeutic effect of different animal bile powders on lipid metabolism disorders induced by high-fat diet in rats, and analyze the bioactive components of each animal bile powder.

METHODS

Sixty Sprague-Dawley rats were randomly divided into 6 groups (n=10): normal diet control group, high-fat diet model group, high-fat diet groups orally treated with bear, pig, cow and chicken bile powders, respectively. Serum biochemical markers from the abdominal aorta in each group were analyzed. Changes in the body weight and liver weight were recorded. Pathohistological changes in the livers were examined. High performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was used to determine the composition of bioactive components in each animal bile powder.

RESULTS

Treatment with different types of animal bile powders had different inhibitory effects on high-fat diet-induced increase of body weight and/or liver weight in rats, most notably in bear and pig bile powders (P<0.05). High-fat diet induced lipid metabolism disorder in rats, which could be reversed by treatment with all kinds of bile powders. Bear bile and chicken bile showed the most potent therapeutic effect against lipid metabolism disorder. Cow and bear bile effectively alleviated high-fat diet induced liver enlargement and discoloration, hepatocyte swelling, infiltration of inflammatory cells and formation of lipid vacuoles. Bioactive component analysis revealed that there were significant differences in the relative content of taurocholic acid, taurodeoxycholic acid and ursodeoxycholic acid among different types of animal bile. Interestingly, a unique component with molecular weight of 496.2738 Da, whose function has not yet been reported, was identified only in bear bile powder.

CONCLUSIONS

Different animal bile powders had varying therapeutic effect against lipid metabolism disorders induced by high-fat diet, and bear bile powder demonstrated the most effective benefits. Bioactive compositions were different in different types of animal bile with a novel compound identified only in bear bile powder.

How does hepatic lipid accumulation lead to lipotoxicity in non-alcoholic fatty liver disease?

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), characterized as excess lipid accumulation in the liver which is not due to alcohol use, has emerged as one of the major health problems around the world. The dysregulated lipid metabolism creates a lipotoxic environment which promotes the development of NAFLD, especially the progression from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH).

PURPOSEAND AIM

This review focuses on the mechanisms of lipid accumulation in the liver, with an emphasis on the metabolic fate of free fatty acids (FFAs) in NAFLD and presents an update on the relevant cellular processes/mechanisms that are involved in lipotoxicity. The changes in the levels of various lipid species that result from the imbalance between lipolysis/lipid uptake/lipogenesis and lipid oxidation/secretion can cause organellar dysfunction, e.g. ER stress, mitochondrial dysfunction, lysosomal dysfunction, JNK activation, secretion of extracellular vesicles (EVs) and aggravate (or be exacerbated by) hypoxia which ultimately lead to cell death. The aim of this review is to provide an overview of how abnormal lipid metabolism leads to lipotoxicity and the cellular mechanisms of lipotoxicity in the context of NAFLD.

Cholesterol, lipoproteins, and COVID-19: Basic concepts and clinical applications

Cholesterol is being recognized as a molecule involved in regulating the entry of the SARS-CoV-2 virus into the host cell. However, the data about the possible role of cholesterol carrying lipoproteins and their receptors in relation to infection are scarce and the connection of lipid-associated pathologies with COVID-19 disease is in its infancy. Herein we provide an overview of lipids and lipid metabolism in relation to COVID-19, with special attention on different forms of cholesterol. Cholesterol enriched lipid rafts represent a platform for viruses to enter the host cell by endocytosis. Generally, higher membrane cholesterol coincides with higher efficiency of COVID-19 entry. Inversely, patients with COVID-19 show lowered levels of blood cholesterol, high-density lipoproteins (HDL) and low-density lipoproteins. The modulated efficiency of viral entry can be explained by availability of SR-B1 receptor. HDL seems to have a variety of roles, from being itself a scavenger for viruses, an immune modulator and mediator of viral entry. Due to inverse roles of membrane cholesterol and lipoprotein cholesterol in COVID-19 infected patients, treatment of these patients with cholesterol lowering statins needs more attention. In conclusion, cholesterol and lipoproteins are potential markers for monitoring the viral infection status, while the lipid metabolic pathways and the composition of membranes could be targeted to selectively inhibit the life cycle of the virus as a basis for antiviral therapy.

Jaboticaba (Myrciaria cauliflora) Peel Supplementation Prevents Hepatic Steatosis Through Hypolipidemic Effects and Cholesterol Metabolism Modulation in Diet-Induced NAFLD Rat Model

Jaboticaba (Myrciaria cauliflora), a Brazilian fruit, is a good source of dietary fiber and phenolic compounds, which are concentrated mainly in the peel. These compounds have been considered promising in prevention and treatment of hypercholesterolemia and hepatic steatosis. In this study, we investigated the effects of 4% jaboticaba peel powder (JPP) supplementation on cholesterol metabolism and hepatic steatosis in livers of rats fed a high-fat (HF) diet. The rats were fed a standard AIN-93M (control) diet or an HF diet containing 32% lard and 1% cholesterol, both with and without 4% JPP. The M. cauliflora peel composition revealed a low-lipid high-fiber content and phenolic compounds. The phenolic compounds in JPP, tentatively identified by high-performance liquid chromatography and mass spectrometry (HPLC-MS/MS) analysis, were confirmed to contain phenolic acids, flavonoids, and anthocyanins. Moreover, JPP presented significant antioxidant activity in vitro and was not cytotoxic to HepG2 cells, as determined by the lactate dehydrogenase (LDH) assay. After 6 weeks of treatment, our results showed that JPP supplementation increased lipid excretion in feces, reduced serum levels of total cholesterol and nonhigh-density lipoprotein cholesterol, decreased serum aspartate aminotransferase (AST) activity, and attenuated hepatic steatosis severity in rats fed the HF diet. Furthermore, JPP treatment downregulated expression of ACAT-1, LXR-α, CYP7A1, and ABCG5 genes. Therefore, jaboticaba peel may represent a viable dietary strategy to prevent nonalcoholic fatty liver disease as the JPP treatment alleviated hepatic steatosis through improvement of serum lipid profiles and modulation of mRNA expression of genes involved in cholesterol metabolism.

Laparoscopic sleeve gastrectomy alters 1H-NMR-measured lipoprotein and glycoprotein profile in patients with severe obesity and nonalcoholic fatty liver disease

Patients with morbid obesity frequently present non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH) associated with pro-atherogenic alterations. Laparoscopic sleeve gastrectomy (LSG) is an effective treatment for weight reduction, and for the remission of hepatic alterations. Using ¹H-nuclear magnetic resonance (¹H-NMR), we investigated the effects of LSG on lipoprotein and glycoprotein profile in patients with morbid obesity and liver disease. We included 154 patients with morbid obesity (49 non-NASH, 54 uncertain NASH, 51 definite NASH). A blood sample was obtained before surgery and, in patients with definite NASH, one year after surgery. Patients with NASH had increased concentrations of medium and small VLDL particles, VLDL and IDL cholesterol concentrations, IDL, LDL, and HDL triglyceride concentrations, and elevated glycoprotein levels. These changes were more marked in patients with type 2 diabetes mellitus. LSG produced significant decreases in the concentration of VLDL particles, VLDL cholesterol and triglycerides, an increase in the concentration LDL particles and LDL cholesterol concentrations, and a decrease in protein glycation. We conclude that patients with obesity and NASH had significant alterations in circulating levels of lipoproteins and glycoproteins that were associated with the severity of the disease. Most of these changes were reversed post-LSG.

Evaluation Through the Optical Coherence Tomography Analysis of the Influence of Non-Alcoholic Fatty Liver Disease on the Gingival Inflammation in Periodontal Patients

PURPOSE

The purpose of this ex vivo study is to exhibit the inflammatory changes that occur within the gingival tissue by using optical coherence tomography (OCT) in periodontal patients with non-alcoholic fatty liver disease (NAFLD) and if NAFLD could influence the local periodontal inflammation.

PATIENTS AND METHODS

Gingival tissue samples obtained from patients were divided into three groups - P (periodontitis), NAFLD+P (NAFLD+periodontitis) and H (healthy) groups - and were scanned using an OCT light beam, in order to perform a qualitative and quantitative analysis of images. The value of average pixel density has been associated with the degree of inflammation.

RESULTS

The highest average pixel density was found in patients from the H group, while the lowest value of average pixel density was recorded in gingival tissue samples collected from patients with NAFLD+P. The image assessments from NAFLD+P group delivered lower values of average pixel density than those of P group, suggesting a possible influence of this disease on the inflammatory tissular changes produced by periodontal disease.

CONCLUSION

After comparing the OCT analysis results obtained for the three groups of patients, we can consider that NAFLD may be an aggravating factor for the inflammation of periodontal disease.

Hepatic Mediators of Lipid Metabolism and Ketogenesis: Focus on Fatty Liver and Diabetes

BACKGROUND

Diabetes mellitus (DM) is a chronic disorder that it is caused by the absence of insulin secretion due to the inability of the pancreas to produce it (type 1 diabetes; T1DM), or due to defects of insulin signaling in the peripheral tissues, resulting in insulin resistance (type 2 diabetes; T2DM). Commonly, the occurrence of insulin resistance in T2DM patients reflects the high prevalence of obesity and non-alcoholic fatty liver disease (NAFLD) in these individuals. In fact, approximately 60% of T2DM patients are also diagnosed to have NAFLD, and this condition is strongly linked with insulin resistance and obesity. NAFLD is the hepatic manifestation of obesity and metabolic syndrome and includes a spectrum of pathological conditions, which range from simple steatosis (NAFL), non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. NAFLD manifestation is followed by a series of hepatic lipid deregulations and the main abnormalities are increased triglyceride levels, increased hepatic production of VLDL and a reduction in VLDL catabolism. During the progression of NAFLD, the production of ketone bodies progressively reduces while hepatic glucose synthesis and output increases. In fact, most of the fat that enters the liver can be disposed of through ketogenesis, preventing the development of NAFLD and hyperglycemia.

OBJECTIVE

This review will focus on the pathophysiological aspect of hepatic lipid metabolism deregulation, ketogenesis, and its relevance in the progression of NAFLD and T2DM.

CONCLUSION

A better understanding of the molecular mediators involved in lipid synthesis and ketogenesis can lead to new treatments for metabolic disorders in the liver, such as NAFLD.

Microbe-set enrichment analysis facilitates functional interpretation of microbiome profiling data

The commensal microbiome is known to influence a variety of host phenotypes. Microbiome profiling followed by differential abundance analysis has been established as an effective approach to study the mechanisms of host-microbiome interactions. However, it is challenging to interpret the collective functions of the resultant microbe-sets due to the lack of well-organized functional characterization of commensal microbiome. We developed microbe-set enrichment analysis (MSEA) to enable the functional interpretation of microbe-sets by examining the statistical significance of their overlaps with annotated groups of microbes that share common attributes such as biological function or phylogenetic similarity. We then constructed microbe-set libraries by query PubMed to find microbe-mammalian gene associations and disease associations by parsing the Disbiome database. To demonstrate the utility of our novel MSEA methodology, we carried out three case studies using publicly available curated knowledge resource and microbiome profiling datasets focusing on human diseases. We found MSEA not only yields consistent findings with the original studies, but also recovers insights about disease mechanisms that are supported by the literature. Overall, MSEA is a useful knowledge-based computational approach to interpret the functions of microbes, which can be integrated with microbiome profiling pipelines to help reveal the underlying mechanism of host-microbiome interactions.

Insulin resistance dysregulates CYP7B1 leading to oxysterol accumulation: a pathway for NAFL to NASH transition

NAFLD is an important public health issue closely associated with the pervasive epidemics of diabetes and obesity. Yet, despite NAFLD being among the most common of chronic liver diseases, the biological factors responsible for its transition from benign nonalcoholic fatty liver (NAFL) to NASH remain unclear. This lack of knowledge leads to a decreased ability to find relevant animal models, predict disease progression, or develop clinical treatments. In the current study, we used multiple mouse models of NAFLD, human correlation data, and selective gene overexpression of steroidogenic acute regulatory protein (StarD1) in mice to elucidate a plausible mechanistic pathway for promoting the transition from NAFL to NASH. We show that oxysterol 7α-hydroxylase (CYP7B1) controls the levels of intracellular regulatory oxysterols generated by the "acidic/alternative" pathway of cholesterol metabolism. Specifically, we report data showing that an inability to upregulate CYP7B1, in the setting of insulin resistance, results in the accumulation of toxic intracellular cholesterol metabolites that promote inflammation and hepatocyte injury. This metabolic pathway, initiated and exacerbated by insulin resistance, offers insight into approaches for the treatment of NAFLD.

Ultrastructure of Hepatocytes from Laboratory Mice Fed a Standard Dry Laboratory Animal Diet

The significant destructive changes in ultrastructure of hepatocytes from laboratory mice kept in different vivariums in Moscow and fed with dry laboratory animal diets acquired from different domestic manufacturers that were not standardized for initial products were demonstrated using electron microscopy. Furthermore, disruption in the ultrastructure of liver parenchymal cells occurred regardless of the animal status (SPF or conventional), conditions of various vivariums, as well as the feed manufacturer. At the same time, studies on ultrastructure of liver hepatocytes from mice kept in the Charles River Laboratory facilities in Germany and fed with the Altromin Spezialfutter laboratory animal diet (GmbH & Co., Germany) that was produced using quality control of ingredients did not reveal destructive changes in the internal ultrastructure of hepatocytes. However, if these mice were later fed with the food produced in local manufactures, changes in the structure of liver cells developed after 2 months. Thus, feeding with dry diet from the domestic producers of an unspecified composition causes significant changes in the ultrastructure of hepatocytes in control animals, reflecting the development of some pathological processes in the body.

Roles of Nrf2 in Liver Diseases: Molecular, Pharmacological, and Epigenetic Aspects

Liver diseases represent a critical health problem with 2 million deaths worldwide per year, mainly due to cirrhosis and its complications. Oxidative stress plays an important role in the development of liver diseases. In order to maintain an adequate homeostasis, there must be a balance between free radicals and antioxidant mediators. Nuclear factor erythroid 2-related factor (Nrf2) and its negative regulator Kelch-like ECH-associated protein 1 (Keap1) comprise a defense mechanism against oxidative stress damage, and growing evidence considers this signaling pathway as a key pharmacological target for the treatment of liver diseases. In this review, we provide detailed and updated evidence regarding Nrf2 and its involvement in the development of the main liver diseases such as alcoholic liver damage, viral hepatitis, steatosis, steatohepatitis, cholestatic damage, and liver cancer. The molecular and cellular mechanisms of Nrf2 cellular signaling are elaborated, along with key and relevant antioxidant drugs, and mechanisms on how Keap1/Nrf2 modulation can positively affect the therapeutic response are described. Finally, exciting recent findings about epigenetic modifications and their link with regulation of Keap1/Nrf2 signaling are outlined.

Higher non-HDL-cholesterol to HDL-cholesterol ratio is linked to increase in non-alcoholic fatty liver disease: secondary analysis based on a longitudinal study

BACKGROUND

Non-high-density lipoprotein cholesterol (non-HDLc) to HDLc ratio (non-HDLc/HDLc), is a viable predictor of metabolic syndrome, insulin resistance, and other cardiac diseases. The study aimed to assess whether non-HDLC/HDLc ratio is an independent predictor of NAFLD.

METHODS

The present study was a longitudinal study, involving 16173 Chinese men and women, aging 14-95 years old, who received a medical check-up program in a health examination Center in China. A total of 16173 initially NAFLD-free non-obese individuals were included, who completed a 5-year follow-up examination in the longitudinal study. NAFLD was defined by ultrasonographic detection of steatosis in the absence of other liver disease. Univariate and multivariate Cox proportional hazards analyses were used to assess the association between nonHDLC/HDLc and NAFLD. ROC curve analysis was performed to compare the predictive value between the nonHDLc/HDLc and the nonHDLc for NAFLD.

RESULTS

During the five-year follow-up period, a total of 2322 participants (14.4%) developed NAFLD. The HRs for NAFLD in the longitudinal population were 1.3 (95% CI 1.1 to 1.7) and 1.5 (95% CI 1.1 to 2.0) compared with Q1. AUC values for nonHDLc/HDLc ratios (0.705) were significantly higher than nonHDLc (0.656) (P<0.05), while the cut-off value for the detection of NAFLD was 2.26. Individuals with higher nonHDLc/HDLc ratio had an increased cumulative incidence rate of NAFLD in non-obese individuals.

CONCLUSION

The Non-HDLc ratio/HDLc is an independent predictor of NAFLD. This may help with early identification of high-risk individuals.

Predicting Nonalcoholic Fatty Liver Disease through a Panel of Plasma Biomarkers and MicroRNAs in Female West Virginia Population

(1) Background: Nonalcoholic fatty liver disease (NAFLD) is primarily characterized by the presence of fatty liver, hepatic inflammation and fibrogenesis eventually leading to nonalcoholic steatohepatitis (NASH) or cirrhosis. Obesity and diabetes are common risk factors associated with the development and progression of NAFLD, with one of the highest prevalence of these diseased conditions in the West Virginia population. Currently, the diagnosis of NAFLD is limited to radiologic studies and biopsies, which are not cost-effective and highly invasive. Hence, this study aimed to develop a panel and assess the progressive levels of circulatory biomarkers and miRNA expression in patients at risk for progression to NASH to allow early intervention strategies. (2) Methods: In total, 62 female patients were enrolled and blood samples were collected after 8–10 h of fasting. Computed tomography was performed on abdomen/pelvis following IV contrast administration. The patients were divided into the following groups: Healthy subjects with normal BMI and normal fasting blood glucose (Control, n = 20), Obese with high BMI and normal fasting blood glucose (Obese, n = 20) and Obese with high fasting blood glucose (Obese + DM, n = 22). Based on findings from CT, another subset was created from Obese + DM group with patients who showed signs of fatty liver infiltration (Obese + DM(FI), n = 10). ELISA was performed for measurement of plasma biomarkers and RT-PCR was performed for circulating miRNA expression. (3) Results: Our results show significantly increased levels of plasma IL-6, Leptin and FABP-1, while significantly decreased level of adiponectin in Obese, Obese + DM and Obese + DM(FI) group, as compared to healthy controls. The level of CK-18 was significantly increased in Obese + DM(FI) group as compared to control. Subsequently, the expression of miR-122, miR-34a, miR-375, miR-16 and miR-21 was significantly increased in Obese + DM and Obese + DM(FI) group as compared to healthy control. Our results also show distinct correlation of IL-6, FABP-1 and adiponectin levels with the expression of miRNAs in relation to the extent of NAFLD progression. (4) Conclusion: Our results support the clinical application of these biomarkers and miRNAs in monitoring the progression of NAFLD, suggesting a more advanced diagnostic potential of this panel than conventional methods. This panel may provide an appropriate method for early prognosis and management of NAFLD and subsequent adverse hepatic pathophysiology, potentially reducing the disease burden on the West Virginia population.

Increased atherogenic lipoprotein profile in children with non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has been shown to be an independent risk factor for cardiovascular disease. In adults, histologic severity of non-alcoholic steatohepatitis (NASH) is associated with a more atherogenic profile.

OBJECTIVE

To assess cardiovascular disease risk by lipoprotein profile in children with NAFLD and compare to histologic assessment of severity.

METHODS

Nuclear magnetic resonance lipoprotein profile including lipoprotein particle sizes, apolipoproteins and the lipoprotein insulin resistance (LP-IR) index was measured in serum samples collected from 76 children at the time of a clinically indicated liver biopsy for NAFLD. Liver histology was scored using the NASH Clinical Research Network criteria and grouped into NASH or non-NASH.

RESULTS

Children with NASH had higher apolipoprotein B to apolipoprotein AI, ApoB/ApoAI (0.56 [IQR, 0.45-0.70] vs 0.66 [IQR, 0.56-0.79], P = .02) and higher LP-IR index (61 ± 21.9 vs 68 ± 17.3, P = .05) compared to children with non-NASH. Severity of hepatocyte ballooning was associated with higher ApoB/ApoAI ratios (P = .01), while high-density lipoprotein size was inversely associated with hepatic fat accumulation (P = .04).

CONCLUSION

While dyslipidaemia is common among children with NAFLD, this data suggests severity of the histologic features is closely associated with severity of cardiometabolic risk. Further studies are needed to understand the role of treatment of NASH in children to prevent future cardiometabolic disease.

History of Nonalcoholic Fatty Liver Disease

Based on the assumption that characterizing the history of a disease will help in improving practice while offering a clue to research, this article aims at reviewing the history of nonalcoholic fatty liver disease (NAFLD) in adults and children. To this end, we address the history of NAFLD histopathology, which begins in 1980 with Ludwig's seminal studies, although previous studies date back to the 19th century. Moreover, the principal milestones in the definition of genetic NAFLD are summarized. Next, a specific account is given of the evolution, over time, of our understanding of the association of NAFLD with metabolic syndrome, spanning from the outdated concept of "NAFLD as a manifestation of the Metabolic Syndrome", to the more appropriate consideration that NAFLD has, with metabolic syndrome, a mutual and bi-directional relationship. In addition, we also report on the evolution from first intuitions to more recent studies, supporting NAFLD as an independent risk factor for cardiovascular disease. This association probably has deep roots, going back to ancient Middle Eastern cultures, wherein the liver had a significance similar to that which the heart holds in contemporary society. Conversely, the notions that NAFLD is a forerunner of hepatocellular carcinoma and extra-hepatic cancers is definitely more modern. Interestingly, guidelines issued by hepatological societies have lagged behind the identification of NAFLD by decades. A comparative analysis of these documents defines both shared attitudes (e.g., ultrasonography and lifestyle changes as the first approaches) and diverging key points (e.g., the threshold of alcohol consumption, screening methods, optimal non-invasive assessment of liver fibrosis and drug treatment options). Finally, the principal historical steps in the general, cellular and molecular pathogenesis of NAFLD are reviewed. We conclude that an in-depth understanding of the history of the disease permits us to better comprehend the disease itself, as well as to anticipate the lines of development of future NAFLD research.

Identification of Crucial Genetic Factors, Such as PPARγ, that Regulate the Pathogenesis of Fatty Liver Disease in Dairy Cows Is Imperative for the Sustainable Development of Dairy Industry

Frequently occurring fatty liver disease in dairy cows during the perinatal period, a typical type of non-alcoholic fatty liver disease (NAFLD), results in worldwide high culling rates of dairy cows (averagely about 25%) after calving. This has been developing into a critical industrial problem throughout the world, because the metabolic disease severely affects the welfare and economic value of dairy cows. Findings about the molecular mechanisms how the fatty liver disease develops would help scientists to discover novel therapeutic targets for NAFLD. Studies have shown that PPARγ participates or regulates the fat deposition in liver by affecting the biological processes of hepatic lipid metabolism, insulin resistance, gluconeogenesis, oxidative stress, endoplasmic reticulum stress and inflammation, which all contribute to fatty liver. This review mainly focuses on crucial regulatory mechanisms of PPARγ regulating lipid deposition in the liver via direct and/or indirect pathways, suggesting that PPARγ might be a potential critical therapeutic target for fatty liver disease, however, it would be of our significant interest to reveal the pathology and pathogenesis of NAFLD by using dairy cows with fatty liver as an animal model. This review will provide a molecular mechanism basis for understanding the pathogenesis of NAFLD.

Gut microbial fatty acid metabolites (KetoA and KetoC) affect the progression of nonalcoholic steatohepatitis and reverse cholesterol transport metabolism in mouse model

Nonalcoholic steatohepatitis (NASH) is a common liver disease that occurs in both alcoholics and nonalcoholics. Oxidative stress is a possible causative factor for liver diseases including NASH. Gut microorganisms, especially lactic acid bacteria, can produce unique fatty acids, including hydroxy, oxo, conjugated, and partially saturated fatty acids. The oxo fatty acid 10-oxo-11(E)-octadecenoic acid (KetoC) provides potent cytoprotective effects against oxidative stress through activation of Nrf2-ARE pathway. The aim of this study was to explore the preventive and therapeutic effects of gut microbial fatty acid metabolites in a NASH mouse model. The mice were divided into 3 experimental groups and fed as follows: (1) high-fat diet (HFD) (2) HFD mixed with 0.1% KetoA (10-oxo-12(Z)-octadecenoic acid), and (3) HFD mixed with 0.1% KetoC. After 3 weeks of feeding, plasma parameters, liver histology, and mRNA expression of multiple genes were assessed. There was hardly any difference in fat accumulation in the histological study; however, no ballooning occurred in 2/5 mice of KetoC group. Bridging fibrosis was not observed in the KetoA group, although KetoA administration did not significantly suppress fibrosis score (p = 0.10). In addition, KetoC increased the expression level of HDL related genes and HDL cholesterol levels in the plasma. These results indicated that KetoA and KetoC may partly affect the progression of NASH in mice models.

Pathophysiology of Type 2 Diabetes in Children and Adolescents

BACKGROUND

The prevalence of type 2 diabetes (DM) in children is disturbingly increasing in parallel with the increasing childhood obesity. Better knowledge regarding the pathophysiology of type 2 DM in children is paramount to devise an effective management plan.

OBJECTIVE

Discuss the pathophysiology of type 2 DM in children and adolescents.

METHODS AND RESULTS

This is a comprehensive review of the literature on this topic. Type 2 DM in childhood is viewed as a continuum of insulin resistance (IR) which is determined by an underlying genetic predisposition, intrauterine environment, excessive food consumption, continued rapid weight gain, and poor lifestyle. Besides IR, this is compounded by multiple metabolic defects including β-cell dysfunction and inadequate insulin secretion, α-cell dysfunction, hyperglucagonemia and increased hepatic glucose production, lipotoxicity, inflammation, deficiencies in incretin production and action, and increased renal glucose reabsorption. The confluence of genetic and environmental factors underscores the complexity in disease progression.

CONCLUSION

A consistent single risk factor for type 2 DM is obesity and related IR and therefore it is essential to curtail the progression of obesity. It is important to investigate the role of stringent dietary and nutritional approaches, medications that enhance β-cell function and insulin sensitivity.