Clinical indicators for progression of nonalcoholic steatohepatitis to cirrhosis

Modulation of liver lipid metabolic pathways by central nervous system ER stress

Metabolic dysfunction-associated steatotic liver disease (MASLD), considered as the hepatic manifestation of metabolic syndrome, can increase the risk for cardiometabolic diseases. Accumulating reports have implicated the central nervous system in MASLD pathogenesis, specifically endoplasmic reticulum (ER) stress in subfornical organ (SFO) to hypothalamic paraventricular nucleus (PVN) projecting neurons (SFO→PVN). Here, we investigated how ER stress in this neural circuit influences hepatic lipid regulatory pathways that may contribute to MASLD development during obesity. Hepatic steatosis was elicited by feeding C57BL/6J male mice a high-fat diet for 11 wk. Intersectional viral targeting was used to inhibit ER stress in SFO→PVN neurons to examine the contribution of ER stress in this circuit to hepatic lipid acquisition and disposal genes during obesity. Inhibition of ER stress in SFO→PVN neurons of obese mice resulted in a reduction in hepatic triglycerides and lipid acquisition genes that was paralleled by a reduction in liver tyrosine hydroxylase, the rate-limiting enzyme in catecholamine synthesis. Moreover, hepatic tyrosine hydroxylase expression was positively correlated with lipid acquisition but not disposal pathways. These results indicate that ER stress in SFO→PVN neurons may contribute to MASLD through sympathetic nervous system influences, primarily on hepatic lipid acquisition.NEW & NOTEWORTHY Endoplasmic reticulum stress in SFO→PVN neurons modulates hepatic lipid acquisition and disposal pathways during obesity-induced hepatic steatosis. Hepatic tyrosine hydroxylase levels are positively correlated with liver triglyceride levels and lipid acquisition pathway-related genes in diet-induced obese animals.

Prevalence of metabolic dysfunction–associated fatty liver disease among patients with diabetic kidney disease: a systematic review and meta-analysis

Background

Mechanistic relationships between metabolic dysfunction–associated fatty liver disease (MAFLD) and chronic kidney disease are well characterized. Specifically, in type 2 diabetes (T2D), insulin resistance leads to MAFLD, and hyperglycemia leads to microvascular complications such as diabetic kidney disease (DKD). This systematic review and meta-analysis aims to describe the specific association between MAFLD and DKD for the first time.

Methods

PubMed, Web of Science, Google Scholar, and Scopus databases were searched up to February 2023 to identify relevant published articles. After screening the titles, abstracts, and full texts of the retrieved articles, cross-sectional studies and cohorts reporting on MAFLD in patients with DKD were identified and then analyzed.

Results

A total of 2615 articles were identified, of which 5 had sufficient data and fulfilled the eligibility criteria for meta-analysis. A total of 2345 patients with DKD were in the included studies. The prevalence rates of radiologically diagnosed MAFLD among patients with DKD ranged from 25 to 96%. The pooled prevalence rate of radiologically diagnosed MAFLD among patients with DKD was 0.55 (95% CI = 0.21–0.89, I2 = 99.79%, P-value < 0.01).

Conclusion

MAFLD is prevalent in patients with DKD. This finding emphasizes the need for aggressive case finding and then guideline-directed medical therapy of MAFLD, especially in patients with T2D and DKD to prevent further complications. Future studies should investigate mechanisms underpinning MAFLD and DKD in patients with T2D, especially in the context of cardiometabolic risk.

Global Prevalence of Nonalcoholic Fatty Liver Disease: An Updated Review Meta-Analysis comprising a Population of 78 million from 38 Countries

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a global health challenge, with a rising rate in line with other metabolic diseases. We aimed to assess the global prevalence of NAFLD in adult and pediatric populations.

METHODS

PubMed, Scopus and Web of Science databases were systematically searched up to May 2023. Heterogeneity was assessed using Cochran's Q test and I2 statistics, and random-effects model was used for meta-analysis. Analyses were performed using STATA version 18.

RESULTS

A total of 479 studies with 78,001,755 participants from 38 countries were finally included. The global prevalence of NAFLD was estimated to be 30.2% (95% CI: 28.7-31.7%). Regionally, the prevalence of NAFLD was as follows: Asia 30.9% (95% CI: 29.2-32.6%), Australia 16.1% (95% CI: 9.0-24.8%), Europe 30.2% (95% CI: 25.6-35.0%), North America 29% (95% CI: 25.8-32.3%), and South America 34% (95% CI: 16.9-53.5%). Countries with a higher human development index (HDI) had significantly lower prevalence of NAFLD (coefficient = -0.523, p = 0.005). Globally, the prevalence of NAFLD in men and women was 36.6% (95% CI: 34.7-38.4%) and 25.5% (95% CI: 23.9-27.1%), respectively. The prevalence of NAFLD in adults, adults with obesity, children, and children with obesity was 30.2% (95% CI: 28.8-31.7%), 57.5% (95% CI: 43.6-70.9%), 14.3% (95% CI: 10.3-18.8%), and 38.0% (95% CI: 31.5-44.7%), respectively.

CONCLUSION

The prevalence of NAFLD is remarkably high, particularly in countries with lower HDI. This substantial prevalence in both adults and children underscores the need for disease management protocols to reduce the burden.

Topiramate's effects on normal and fatty liver

Topiramate (TPM), a carbonic anhydrase (CA) inhibitor, is known for its anti-obesity effect. Even though, nonalcoholic fatty liver disease (NAFLD) is present in 80% of obese patients, TPM's effects on oxidant-antioxidant parameters and CA activity on fatty liver is not known. 24 Wistar albino rats were divided into four groups: control, TPM, diet, and diet + TPM. Diet groups fed with high-fat diet while control and TPM groups received standard chow for six weeks. Than 100 mg/kg/day TPM (po) was added to TPM groups for 21 days. Rats' weight and blood glucose levels were monitored weekly, and at the end of the study liver removed for biochemical and histological analysis. TPM eliminated the increases in weight and blood glucose levels caused by high-fat diet. TPM decreased CA activity in all groups. MDA levels increased significantly in TPM and DT groups (p = 0.004; p = 0.008). GSH levels were decreased in the TPM, D and DT groups (p = 0.004; p = 0.015; p = 0.003). Similarly, GPx activity levels were significantly decreased in all groups. Histological evaluation revealed notable infiltration, eosinophilia and cytoplasmic vacuolization in the TPM group. Steatosis and NAFLD activity score (NAS) were higher in the diet group. Ballooning, infiltration and NAS were higher in the diet + TPM group compared to control. CA activity negatively correlated with MDA (p < 0.001), and positively correlated with GSH (p < 0.001). TPM caused oxidant stress and liver damage, which are exacerbated in NAFLD induced rats. Therefore, use of TPM in patients with liver disease should be considered very carefully.

Association of the hemoglobin glycation index with cardiovascular and all-cause mortality in individuals with hypertension: findings from NHANES 1999-2018

BACKGROUND

This study examines the association between Hemoglobin Glycation Index (HGI) and the risk of mortality among individuals with hypertension and to explore gender-specific effects.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 were analyzed. Three models were constructed to assess the relationship between HGI and mortality risks, controlling for various covariates. Nonlinear relationships were explored using restricted cubic splines (RCS) and threshold effect analysis.

RESULTS

The findings reveal a U-shaped relationship between HGI and the cardiovascular disease (CVD) and all-cause mortality after adjusting for multiple covariates. Gender- specific analysis indicated a U-shaped relationship in men, with threshold points of -0.271, and 0.115, respectively. Before the threshold point, HGI was negatively associated with CVD mortality (HR: 0.64, 95%CI: 0.44, 0.93, P=0.02) and all-cause mortality (HR: 0.84, 95%CI: 0.71, 0.99), and after the threshold point, HGI was positively associated with CVD mortality (HR: 1.48, 95%CI: 1.23, 1.79, P<0.01) and all-cause mortality (HR: 1.41, 95%CI: 1.24, 1.60). In contrast, HGI had a J-shaped relationship with CVD mortality and a L-shaped relationship with all-cause mortality in females. Before the threshold points, the risk of all-cause mortality decreased (HR: 0.66, 95%CI:0.56, 0.77, P=0.04) and after the threshold points, the risk of CVD mortality increased (HR: 1.39, 95%CI:1.12, 1.72, P<0.01) progressively with increasing HGI.

CONCLUSION

The research highlights the significance of maintaining proper HGI levels in individuals with hypertension and validates HGI as a notable indicator of cardiovascular and all-cause mortality risks. It also highlights the significant role of gender in the relationship between HGI and these risks.

Hepatic DDAH1 mitigates hepatic steatosis and insulin resistance in obese mice: Involvement of reduced S100A11 expression

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is an important regulator of plasma asymmetric dimethylarginine (ADMA) levels, which are associated with insulin resistance in patients with nonalcoholic fatty liver disease (NAFLD). To elucidate the role of hepatic DDAH1 in the pathogenesis of NAFLD, we used hepatocyte-specific Ddah1-knockout mice (Ddah1HKO) to examine the progress of high-fat diet (HFD)-induced NAFLD. Compared to diet-matched flox/flox littermates (Ddah1f/f), Ddah1HKO mice exhibited higher serum ADMA levels. After HFD feeding for 16 weeks, Ddah1HKO mice developed more severe liver steatosis and worse insulin resistance than Ddah1f/f mice. On the contrary, overexpression of DDAH1 attenuated the NAFLD-like phenotype in HFD-fed mice and ob/ob mice. RNA-seq analysis showed that DDAH1 affects NF-κB signaling, lipid metabolic processes, and immune system processes in fatty livers. Furthermore, DDAH1 reduces S100 calcium-binding protein A11 (S100A11) possibly via NF-κB, JNK and oxidative stress-dependent manner in fatty livers. Knockdown of hepatic S100a11 by an AAV8-shS100a11 vector alleviated hepatic steatosis and insulin resistance in HFD-fed Ddah1HKO mice. In summary, our results suggested that the liver DDAH1/S100A11 axis has a marked effect on liver lipid metabolism in obese mice. Strategies to increase liver DDAH1 activity or decrease S100A11 expression could be a valuable approach for NAFLD therapy.

NIK/MAP3K14 in hepatocytes orchestrates NASH to hepatocellular carcinoma progression via JAK2/STAT5 inhibition

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) ranges from steatosis to nonalcoholic steatohepatitis (NASH), which often progresses to hepatocellular carcinoma (HCC) through a largely undefined mechanism. NASH and HCC depend on inflammatory signaling, whose master regulator is the NFκB transcription factor family, activated by canonical and non-canonical pathways.

METHODS

Here, we investigated non-canonical NFκB-inducing kinase (NIK/MAP3K14) in metabolic NASH, NASH to HCC transition, and DEN-induced HCC. To this end, we performed dietary and chemical interventions in mice that were analyzed via single nucleus sequencing, gene expression and histochemical methods. Ultimately, we verified our mouse results in human patient samples.

RESULTS

We revealed that hepatocyte-specific NIK deficiency (NIKLKO) ameliorated metabolic NASH complications and reduced hepatocarcinogenesis, independent of its role in the NFκB pathway. Instead, hepatic NIK attenuated hepatoprotective JAK2/STAT5 signaling that is a prerequisite for NASH and NASH to HCC progression in mice and humans.

CONCLUSIONS

Our data suggest NIK-mediated inhibitory JAK2 phosphorylation at serine 633 that might be amenable for future therapeutic interventions in patients.

A liver secretome gene signature-based approach for determining circulating biomarkers of NAFLD severity

Non-invasive biomarkers of non-alcoholic fatty liver disease (NAFLD) supporting diagnosis and monitoring disease progression are urgently needed. The present study aimed to establish a bioinformatics pipeline capable of defining and validating NAFLD biomarker candidates based on paired hepatic global gene expression and plasma bioanalysis from individuals representing different stages of histologically confirmed NAFLD (no/mild, moderate, more advanced NAFLD). Liver secretome gene signatures were generated in a patient cohort of 26 severely obese individuals with the majority having no or mild fibrosis. To this end, global gene expression changes were compared between individuals with no/mild NAFLD and moderate/advanced NAFLD with subsequent filtering for candidate gene products with liver-selective expression and secretion. Four candidate genes, including LPA (lipoprotein A), IGFBP-1 (insulin-like growth factor-binding protein 1), SERPINF2 (serpin family F member 2) and MAT1A (methionine adenosyltransferase 1A), were differentially expressed in moderate/advanced NAFLD, which was confirmed in three independent RNA sequencing datasets from large, publicly available NAFLD studies. The corresponding gene products were quantified in plasma samples but could not discriminate among different grades of NAFLD based on NAFLD activity score. Conclusion: We demonstrate a novel approach based on the liver transcriptome allowing for identification of secreted hepatic gene products as potential circulating diagnostic biomarkers of NAFLD. Using this approach in larger NAFLD patient cohorts may yield potential circulating biomarkers for NAFLD severity.

A new detection system for serum fragmented cytokeratin 18 as a biomarker reflecting histologic activities of human nonalcoholic steatohepatitis

Caspase-generated fragmented cytokeratin 18 (fCK18) is recognized as a useful noninvasive biomarker in the diagnosis of nonalcoholic fatty liver disease (NAFLD), particularly nonalcoholic steatohepatitis (NASH). However, fCK18 measurement is not applied clinically due to widely variable cut-off values under the current enzyme-linked immunosorbent assay platform. Therefore, we developed a highly sensitive chemiluminescent enzyme immunoassay using newly developed monoclonal antibodies against fCK18 and investigated its relevance in NASH diagnosis. Serum fCK18 levels were measured in the derivation and validation cohort. The correlation between serum fCK18 levels and NAFLD activity score (NAS), fibrosis stage, and liver function was examined. Serum fCK18 levels were significantly correlated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase. Serum fCK18 levels were significantly associated with NAS, Brunt's grade/stage, Matteoni's classification, portal inflammation, and fat accumulation in the liver. Notably, hepatocyte ballooning was the only independent variable significantly associated with serum fCK18 in the multivariate linear regression analysis. Serum fCK18 levels were significantly elevated in patients with NAFLD and nonalcoholic fatty liver (NAFL) compared to healthy individuals. They were also significantly elevated in patients with NAFL compared to NASH defined by NAS or Matteoni's classification, with area under the curve values being 0.961 (NAFLD vs. healthy), 0.913 (NAFL vs. healthy), 0.763 (NASH vs. NAFL), and 0.796 (NASH type 3-4 vs. NAFL type 1-2). These results were confirmed by a validation cohort. Notably, changes over time in serum fCK18 levels were significantly correlated with changes in ALT, AST, and the fibrosis-4 index in 25 patients who underwent lifestyle modification. Serum fCK18 levels were significantly correlated with liver damage associated with NASH pathology. Serum fCK18 levels are accurate in distinguishing patients with NAFL or NASH from healthy individuals and may be useful to monitor NASH over time.

Cholesterol metabolism in aging simultaneously altered in liver and nervous system

In humans, aging, triggers increased plasma concentrations of triglycerides, cholesterol, low-density lipoproteins and lower capacity of high-density lipoproteins to remove cellular cholesterol. Studies in rodents showed that aging led to cholesterol accumulation in the liver and decrease in the brain with reduced cholesterol synthesis and increased levels of cholesterol 24-hydroxylase, an enzyme responsible for removing cholesterol from the brain. Liver diseases are also related to brain aging, inducing changes in cholesterol metabolism in the brain and liver of rats. It has been suggested that late onset Alzheimer's disease is associated with metabolic syndrome. Non-alcoholic fatty liver is associated with lower total brain volume in the Framingham Heart Study offspring cohort study. Furthermore, disorders of cholesterol homeostasis in the adult brain are associated with neurological diseases such as Niemann-Pick, Alzheimer, Parkinson, Huntington and epilepsy. Apolipoprotein E (apoE) is important in transporting cholesterol from astrocytes to neurons in the etiology of sporadic Alzheimer's disease, an aging-related dementia. Desmosterol and 24S-hydroxycholesterol are reduced in ApoE KO hypercholesterolemic mice. ApoE KO mice have synaptic loss, cognitive dysfunction, and elevated plasma lipid levels that can affect brain function. In contrast to cholesterol itself, there is a continuous uptake of 27- hydroxycholesterol in the brain as it crosses the blood-brain barrier and this flow can be an important link between intra- and extracerebral cholesterol homeostasis. Not surprisingly, changes in cholesterol metabolism occur simultaneously in the liver and nervous tissues and may be considered possible biomarkers of the liver and nervous system aging.