Antibiotics attenuate diet-induced nonalcoholic fatty liver disease without altering intestinal barrier dysfunction

Metabolic disorders, inter-organ crosstalk, and inflammation in the progression of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a global health concern, affecting over 30 % of adults. It is a principal driver in the development of cirrhosis and hepatocellular carcinoma. The complex pathogenesis of MASLD involves an excessive accumulation of lipids, subsequently disrupting lipid metabolism and prompting inflammation within the liver. This review synthesizes the recent research progress in understanding the mechanisms contributing to MASLD progression, with particular emphasis on metabolic disorders and interorgan crosstalk. We highlight the molecular mechanisms linked to these factors and explore their potential as novel targets for pharmacological intervention. The insights gleaned from this article have important implications for both the prevention and therapeutic management of MASLD.

Gut microbes, diet, and genetics as drivers of metabolic liver disease: a narrative review outlining implications for precision medicine

Metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing in prevalence, impacting over a third of the global population. The advanced form of MASLD, Metabolic dysfunction-associated steatohepatitis (MASH), is on track to become the number one indication for liver transplant. FDA-approved pharmacological agents are limited for MASH, despite over 400 ongoing clinical trials, with only a single drug (resmetirom) currently on the market. This is likely due to the heterogeneous nature of disease pathophysiology, which involves interactions between highly individualized genetic and environmental factors. To apply precision medicine approaches that overcome interpersonal variability, in-depth insights into interactions between genetics, nutrition, and the gut microbiome are needed, given that each have emerged as dynamic contributors to MASLD and MASH pathogenesis. Here, we discuss the associations and molecular underpinnings of several of these factors individually and outline their interactions in the context of both patient-based studies and preclinical animal model systems. Finally, we highlight gaps in knowledge that will require further investigation to aid in successfully implementing precision medicine to prevent and alleviate MASLD and MASH.

Effect of Ilex hainanensis Merr. On HFD-induced nonalcoholic fatty liver disease and rebalance of gut microbiota and bile acids metabolism in mice

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by excessive intracellular fat deposition in the hepatocytes, and the development is exacerbated by gut microbiota and bile acids metabolism disorders. Ilex hainanensis Merr. is a traditional medicine of the Zhuang nationality, historically esteemed for its efficacy in lowering blood pressure and lipid levels. This study aimed to investigate the pharmacodynamic effects in NAFLD mice and impacts on gut microbiota and bile acids (BAs) metabolism of I. hainanensis extract (IHA). 16 compounds were identified from IHA by HPLC-DAD-MS analysis. IHA significantly reduced body weight indexs, alanine transaminase (ALT) and aspartate transaminase (AST) activities, improved dyslipidemia and insulin resistance (IR), and effectively ameliorated hepatic steatosis in HFD-induced NAFLD mice. IHA also altered gut microbiota composition, particularly enhancing the abundance of bacteria involved in BAs metabolism, as well as augmented BAs synthesis in the liver and increased fecal excretion. In conclusion, our findings suggest that IHA holds promise in improving NAFLD conditions and modulating gut microbiota and BAs metabolism. These insights contribute to a deeper understanding of the mechanisms underlying IHA-mediated alleviation of lipid accumulation in NAFLD.

The Role of Gut Microbiota and Innate Immune Response in an Autoimmune Pancreatitis Model

BACKGROUND

Although the involvement of intestinal microbiota in innate immunity has been reported recently, the pathogenicity of autoimmune pancreatitis (AIP) remains unclear. This study aimed to investigate whether probiotics ameliorate inflammation in AIP through interactions with innate immunity.

MATERIALS AND METHODS

The AIP mouse model was generated by intraperitoneal administration of Escherichia coli to C56BL/6 female mice. Alterations in the intestinal microbiota in the AIP group were evaluated using high-throughput sequencing. Peritoneal macrophages (PMs) were collected and cocultured in vitro with Lactobacillus gasseri (LG) or ligands of Toll-like receptors (TLRs). LG was administered intraperitoneally to AIP model mice, and pancreatitis activity was evaluated to examine the ameliorative effects of LG.

RESULTS

In the AIP model mice, inflammation was significantly induced in the pancreas, and the intestinal microbiota was altered with decreased LG. Antimicrobial treatment suppressed pancreatitis. In vitro, E. coli stimulation increased inflammatory cytokine expression, which was significantly decreased when the LG or TLR7 ligand was cocultured with PMs. Intraperitoneal administration of LG to AIP model mice significantly suppressed pancreatitis.

CONCLUSION

The mouse model demonstrated the involvement of intestinal microbiota in pancreatitis, and LG administration suppressed pancreatitis, possibly through TLR7 signaling in PMs. LG may be a helpful probiotic for treating AIP.

The relevance of intestinal barrier dysfunction, antimicrobial proteins and bacterial endotoxin in metabolic dysfunction-associated steatotic liver disease

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a leading cause of end-stage liver disease associated with increased mortality and cardiovascular disease. Obesity and diabetes are the most important risk factors of MASLD. It is well-established that obesity-associated insulin resistance leads to a situation of tissue lipotoxicity characterized by an accumulation of excess fat in non-fat tissues such as the liver, promoting the development of MASLD, and its progression into metabolic dysfunction-associated steatohepatitis.

METHODS

Here, we aimed to review the impact of disrupted intestinal permeability, antimicrobial proteins and bacterial endotoxin in the development and progression of MASLD.

RESULTS AND CONCLUSION

Recent studies demonstrated that obesity- and obesogenic diets-associated alterations of intestinal microbiota along with the disruption of intestinal barrier integrity, the alteration in antimicrobial proteins and, in consequence, an enhanced translocation of bacterial endotoxin into bloodstream might contribute to this pathological process through to impacting liver metabolism and inflammation.

Could Adverse Effects of Antibiotics Due to Their Use/Misuse Be Linked to Some Mechanisms Related to Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease, recently re-named metabolic dysfunction-associated steatotic fatty liver disease, is considered the most prevalent liver disease worldwide. Its molecular initiation events are multiple and not always well-defined, comprising insulin resistance, chronic low-grade inflammation, gut dysbiosis, and mitochondrial dysfunction, all of them acting on genetic and epigenetic grounds. Nowadays, there is a growing public health threat, which is antibiotic excessive use and misuse. This widespread use of antibiotics not only in humans, but also in animals has led to the presence of residues in derived foods, such as milk and dairy products. Furthermore, antibiotics have been used for many decades to control certain bacterial diseases in high-value fruit and vegetables. Recently, it has been emphasised that antibiotic-induced changes in microbial composition reduce microbial diversity and alter the functional attributes of the microbiota. These antibiotic residues impact human gut flora, setting in motion a chain of events that leads straight to various metabolic alterations that can ultimately contribute to the onset and progression of NAFLD.