scholarly journals Gut Microbiota-Related Cellular and Molecular Mechanisms in the Progression of Nonalcoholic Fatty Liver Disease

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2634
Author(s):  
Eunju Park ◽  
Jin-Ju Jeong ◽  
Sung-Min Won ◽  
Satya Priya Sharma ◽  
Yoseph Asmelash Gebru ◽  
...  

Nonalcoholic fatty liver disease (NAFLD) is one of the most common and increasing liver diseases worldwide. NAFLD is a term that involves a variety of conditions such as fatty liver, steatohepatitis, or fibrosis. Gut microbiota and its products have been extensively studied because of a close relation between NAFLD and microbiota in pathogenesis. In the progression of NAFLD, various microbiota-related molecular and cellular mechanisms, including dysbiosis, leaky bowel, endotoxin, bile acids enterohepatic circulation, metabolites, or alcohol-producing microbiota, are involved. Currently, diagnosis and treatment techniques using these mechanisms are being developed. In this review, we will introduce the microbiota-related mechanisms in the progression of NAFLD and future directions will be discussed.

2020 ◽  
Author(s):  
Olena H. Kurinna

AbstractNonalcoholic fatty liver disease (NAFLD) bears serious economic consequences for the health care system worldwide and Ukraine, in particular. Cardiovascular diseases (CVD) are the main cause of mortality in NAFLD patients. Changes in the gut microbiota composition can be regarded as a potential mechanism of CVD in NAFLD patients.The purpose of this work was to investigate changes in major gut microbiota phylotypes, Bacteroidetes, Firmicutes and Actinobacteria with quantification of Firmicutes/Bacteroidetes in NAFLD patients with concomitant CVD.The author enrolled 120 NAFLD subjects (25 with concomitant arterial hypertension (AH) and 24 with coronary artery disease (CAD)). The gut microbiota composition was assessed by qPCR.Resultsthe author found a marked tendency towards an increase in the concentration of Bacteroidetes (by 37.11% and 21.30%, respectively) with a decrease in Firmicutes (by 7.38% and 7.77%, respectively) in both groups with comorbid CAD and AH with the identified changes not reaching a statistical significance. The author quantified a statistically significant decrease in the concentration of Actinobacteria in patients with NAFLD with concomitant CAD at 41.37% (p<0.05) as compared with those with an isolated NAFLD. In patients with concomitant AH, the content of Actinobacteria dropped by 12.35%, which was statistically insignificant.Conclusionsthe author established changes in the intestinal microbiota, namely decrease in Actinobacteria in patients with CAD, which requires further research.


Author(s):  
Jiake Yu ◽  
Hu Zhang ◽  
Liya Chen ◽  
Yufei Ruan ◽  
Yiping Chen ◽  
...  

Children with nonalcoholic fatty liver disease (NAFLD) display an altered gut microbiota compared with healthy children. However, little is known about the fecal bile acid profiles and their association with gut microbiota dysbiosis in pediatric NAFLD. A total of 68 children were enrolled in this study, including 32 NAFLD patients and 36 healthy children. Fecal samples were collected and analyzed by metagenomic sequencing to determine the changes in the gut microbiota of children with NAFLD, and an ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system was used to quantify the concentrations of primary and secondary bile acids. The associations between the gut microbiota and concentrations of primary and secondary bile acids in the fecal samples were then analyzed. We found that children with NAFLD exhibited reduced levels of secondary bile acids and alterations in bile acid biotransforming-related bacteria in the feces. Notably, the decrease in Eubacterium and Ruminococcaceae bacteria, which express bile salt hydrolase and 7α-dehydroxylase, was significantly positively correlated with the level of fecal lithocholic acid (LCA). However, the level of fecal LCA was negatively associated with the abundance of the potential pathogen Escherichia coli that was enriched in children with NAFLD. Pediatric NAFLD is characterized by an altered profile of gut microbiota and fecal bile acids. This study demonstrates that the disease-associated gut microbiota is linked with decreased concentrations of secondary bile acids in the feces. The disease-associated gut microbiota likely inhibits the conversion of primary to secondary bile acids.


2021 ◽  
Vol 22 (18) ◽  
pp. 9969
Author(s):  
Mariano Schiffrin ◽  
Carine Winkler ◽  
Laure Quignodon ◽  
Aurélien Naldi ◽  
Martin Trötzmüller ◽  
...  

Men with nonalcoholic fatty liver disease (NAFLD) are more exposed to nonalcoholic steatohepatitis (NASH) and liver fibrosis than women. However, the underlying molecular mechanisms of NALFD sex dimorphism are unclear. We combined gene expression, histological and lipidomic analyses to systematically compare male and female liver steatosis. We characterized hepatosteatosis in three independent mouse models of NAFLD, ob/ob and lipodystrophic fat-specific (PpargFΔ/Δ) and whole-body PPARγ-null (PpargΔ/Δ) mice. We identified a clear sex dimorphism occurring only in PpargΔ/Δ mice, with females showing macro- and microvesicular hepatosteatosis throughout their entire life, while males had fewer lipid droplets starting from 20 weeks. This sex dimorphism in hepatosteatosis was lost in gonadectomized PpargΔ/Δ mice. Lipidomics revealed hepatic accumulation of short and highly saturated TGs in females, while TGs were enriched in long and unsaturated hydrocarbon chains in males. Strikingly, sex-biased genes were particularly perturbed in both sexes, affecting lipid metabolism, drug metabolism, inflammatory and cellular stress response pathways. Most importantly, we found that the expression of key sex-biased genes was severely affected in all the NAFLD models we tested. Thus, hepatosteatosis strongly affects hepatic sex-biased gene expression. With NAFLD increasing in prevalence, this emphasizes the urgent need to specifically address the consequences of this deregulation in humans.


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Jinsheng Yu ◽  
Sharon Marsh ◽  
Junbo Hu ◽  
Wenke Feng ◽  
Chaodong Wu

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, and it comprises a spectrum of hepatic abnormalities from simple hepatic steatosis to steatohepatitis, fibrosis, cirrhosis, and liver cancer. While the pathogenesis of NAFLD remains incompletely understood, a multihit model has been proposed that accommodates causal factors from a variety of sources, including intestinal and adipose proinflammatory stimuli acting on the liver simultaneously. Prior cellular and molecular studies of patient and animal models have characterized several common pathogenic mechanisms of NAFLD, including proinflammation cytokines, lipotoxicity, oxidative stress, and endoplasmic reticulum stress. In recent years, gut microbiota has gained much attention, and dysbiosis is recognized as a crucial factor in NAFLD. Moreover, several genetic variants have been identified through genome-wide association studies, particularly rs738409 (Ile748Met) inPNPLA3and rs58542926 (Glu167Lys) inTM6SF2, which are critical risk alleles of the disease. Although a high-fat diet and inactive lifestyles are typical risk factors for NAFLD, the interplay between diet, gut microbiota, and genetic background is believed to be more important in the development and progression of NAFLD. This review summarizes the common pathogenic mechanisms, the gut microbiota relevant mechanisms, and the major genetic variants leading to NAFLD and its progression.


2021 ◽  
Vol 15 ◽  
Author(s):  
Cheng Ma ◽  
Cheng Wang ◽  
Yafang Zhang ◽  
Honglin Zhou ◽  
Yunxia Li

Background: Nonalcoholic fatty liver disease (NAFLD) is a kind of metabolic stress-induced liver injury closely related to insulin resistance and genetic susceptibility, and there is no specific drug for its clinical treatment currently. In recent years, a large amount of literature has reported that many natural compounds extracted from traditional Chinese medicine (TCM) can improve NAFLD through various mechanisms. According to the latest reports, some emerging natural compounds have shown great potential to improve NAFLD but are seldom used clinically due to the lacking special research. Purpose: This paper aims to summarize the molecular mechanisms of the potential natural compounds on improving NAFLD, thus providing a direction and basis for further research on the pathogenesis of NAFLD and the development of effective drugs for the prevention and treatment of NAFLD. Methods: By searching various online databases, such as Web of Science, SciFinder, PubMed, and CNKI, NAFLD and these natural compounds were used as the keywords for detailed literature retrieval. Results: The pathogenesis of NAFLD and the molecular mechanisms of the potential natural compounds on improving NAFLD have been reviewed. Conclusion: Many natural compounds from traditional Chinese medicine have a good prospect in the treatment of NAFLD, which can serve as a direction for the development of anti-NAFLD drugs in the future.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Caihua Wang ◽  
Chunpeng Zhu ◽  
Liming Shao ◽  
Jun Ye ◽  
Yimin Shen ◽  
...  

Nonalcoholic fatty liver disease (NAFLD) is a major health threat around the world and is characterized by dysbiosis. Primary bile acids are synthesized in the liver and converted into secondary bile acids by gut microbiota. Recent studies support the role of bile acids in modulating dysbiosis and NAFLD, while the mechanisms are not well elucidated. Dysbiosis may alter the size and the composition of the bile acid pool, resulting in reduced signaling of bile acid receptors such as farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5). These receptors are essential in lipid and glucose metabolism, and impaired bile acid signaling may cause NAFLD. Bile acids also reciprocally regulate the gut microbiota directly via antibacterial activity and indirectly via FXR. Therefore, bile acid signaling is closely linked to dysbiosis and NAFLD. During the past decade, stimulation of bile acid receptors with their agonists has been extensively explored for the treatment of NAFLD in both animal models and clinical trials. Early evidence has suggested the potential of bile acid receptor agonists in NAFLD management, but their long-term safety and effectiveness need further clarification.


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