Phenylpropionic acid produced by gut microbiota alleviates acetaminophen-induced hepatotoxicity

Effect of Lacticaseibacillus rhamnosus IDCC 3201 on irritable bowel syndrome with constipation: a randomized, double-blind, and placebo-controlled trial

Irritable bowel syndrome is a chronic disorder affecting the gastrointestinal tract, negatively impacting patients' quality of life. Here, we aimed to evaluate the effects of Lacticaseibacillus rhamnosus IDCC 3201 (RH 3201) on irritable bowel syndrome with constipation (IBS-C). In this randomised, double-blind, placebo-controlled trial, a total of 30 subjects with IBS-C were randomly assigned (1:1) to receive 8 weeks of probiotics administration or placebo. Concerning bowel activities, both irritant bowel movements and discomfort caused by constipation showed significant improvement with RH 3201 at 8 weeks. Symptoms including severity of abdominal bloating, frequency of abdominal bloating, and satisfaction of bowel habits based on the irritable bowel syndrome-severity scoring system also ameliorated in the probiotic group. Analysis of the fecal microbiome revealed that the abundance of Bacteroides cellulosilyticus and Akkermansia muciniphila was higher during the period of RH 3201 administration compared to the placebo. Untargeted metabolome analysis further suggested a correlation between specific metabolites, such as N-acetylornithine, xanthine, and 3-phenylpropionic acid, and the improvement of clinical symptoms. These results indicate that RH 3201 was effective in ameliorating IBS-C, potentially by enriching beneficial microbes and associated metabolites in the gut environment.

The Discovery of Gut Microbial Metabolites as Modulators of Host Susceptibility to Acetaminophen-Induced Hepatotoxicity

The mammalian gut microbiota plays diverse and essential roles in modulating host physiology. Key mediators determining the outcome of the microbiota-host interactions are the small molecule metabolites produced by the gut microbiota. The liver is a major organ exposed to gut microbial metabolites, and it serves as the nexus for maintaining healthy interactions between the gut microbiota and the host. At the same time, the liver is the primary target of potentially harmful gut microbial metabolites. In this review, we provide an up-to-date list of gut microbial metabolites that have been identified to either increase or decrease host susceptibility to acetaminophen (APAP)-induced liver injury. The signaling pathways and molecular factors involved in the progression of APAP-induced hepatotoxicity are well-established, and we propose that the mouse model of APAP-induced hepatotoxicity serves as a model system for uncovering gut microbial metabolites with previously unknown functions. Furthermore, we envision that gut microbial metabolites identified to alter APAP-induced hepatotoxicity likely have broader implications in other liver diseases. SIGNIFICANCE STATEMENT: This review provides an overview of the role of the gut microbiota in modulating the host susceptibility to acetaminophen (APAP)-induced liver injury. It focuses on the roles of gut bacterial small molecule metabolites as mediators of the interaction between the gut microbiota and the liver. It also illustrates the utility of APAP-induced liver injury as a model to identify gut microbial metabolites with biological function.

CYP2E1 deficit mediates cholic acid-induced malignant growth in hepatocellular carcinoma cells

BACKGROUND

Increased level of serum cholic acid (CA) is often accompanied with decreased CYP2E1 expression in hepatocellular carcinoma (HCC) patients. However, the roles of CA and CYP2E1 in hepatocarcinogenesis have not been elucidated. This study aimed to investigate the roles and the underlying mechanisms of CYP2E1 and CA in HCC cell growth.

METHODS

The proteomic analysis of liver tumors from DEN-induced male SD rats with CA administration was used to reveal the changes of protein expression in the CA treated group. The growth of CA-treated HCC cells was examined by colony formation assays. Autophagic flux was assessed with immunofluorescence and confocal microscopy. Western blot analysis was used to examine the expression of CYP2E1, mTOR, AKT, p62, and LC3II/I. A xenograft tumor model in nude mice was used to examine the role of CYP2E1 in CA-induced hepatocellular carcinogenesis. The samples from HCC patients were used to evaluate the clinical value of CYP2E1 expression.

RESULTS

CA treatment significantly increased the growth of HCC cells and promoted xenograft tumors accompanied by a decrease of CYP2E1 expression. Further studies revealed that both in vitro and in vivo, upregulated CYP2E1 expression inhibited the growth of HCC cells, blocked autophagic flux, decreased AKT phosphorylation, and increased mTOR phosphorylation. CYP2E1 was involved in CA-activated autophagy through the AKT/mTOR signaling. Finally, decreased CYP2E1 expression was observed in the tumor tissues of HCC patients and its expression level in tumors was negatively correlated with the serum level of total bile acids (TBA) and gamma-glutamyltransferase (GGT).

CONCLUSIONS

CYP2E1 downregulation contributes to CA-induced HCC development presumably through autophagy regulation. Thus, CYP2E1 may serve as a potential target for HCC drug development.

Role of Gut Microecology in the Pathogenesis of Drug-Induced Liver Injury and Emerging Therapeutic Strategies

Drug-induced liver injury (DILI) is a common clinical pharmacogenic disease. In the United States and Europe, DILI is the most common cause of acute liver failure. Drugs can cause hepatic damage either directly through inherent hepatotoxic properties or indirectly by inducing oxidative stress, immune responses, and inflammatory processes. These pathways can culminate in hepatocyte necrosis. The role of the gut microecology in human health and diseases is well recognized. Recent studies have revealed that the imbalance in the gut microecology is closely related to the occurrence and development of DILI. The gut microecology plays an important role in liver injury caused by different drugs. Recent research has revealed significant changes in the composition, relative abundance, and distribution of gut microbiota in both patients and animal models with DILI. Imbalance in the gut microecology causes intestinal barrier destruction and microorganism translocation; the alteration in microbial metabolites may initiate or aggravate DILI, and regulation and control of intestinal microbiota can effectively mitigate drug-induced liver injury. In this paper, we provide an overview on the present knowledge of the mechanisms by which DILI occurs, the common drugs that cause DILI, the gut microbiota and gut barrier composition, and the effects of the gut microbiota and gut barrier on DILI, emphasizing the contribution of the gut microecology to DILI.

Targeting gut microbiota to counteract acetaminophen-induced acute liver injury

Acetaminophen (N-acetyl-p-aminophenol; APAP) overdose-induced acute liver injury (AILI) is a huge threat to public health worldwide. Recent research clearly shows that the intestinal microbiota (IM) is a key modulator in AILI. Herein, I discuss the latest findings on how the IM regulates AILI and the potential interventions to combat AILI by targeting the IM.

Gut-Liver Axis as a Therapeutic Target for Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a liver disease that remains difficult to predict and diagnose, and the underlying mechanisms are yet to be fully clarified. The gut-liver axis refers to the reciprocal interactions between the gut and the liver, and its homeostasis plays a prominent role in maintaining liver health. It has been recently reported that patients and animals with DILI have a disrupted gut-liver axis, involving altered gut microbiota composition, increased intestinal permeability and lipopolysaccharide translocation, decreased short-chain fatty acids production, and impaired bile acid metabolism homeostasis. The present review will summarize the evidence from both clinical and preclinical studies about the role of the gut-liver axis in the pathogenesis of DILI. Moreover, we will focus attention on the potential therapeutic strategies for DILI based on improving gut-liver axis function, including herbs and phytochemicals, probiotics, fecal microbial transplantation, postbiotics, bile acids, and Farnesoid X receptor agonists.

Mg and the microbiome: A liver-protective duo

Acute liver failure continues to carry high morbidity and mortality with limited therapeutic options. In this issue of Cell Host & Microbe, Li et al. demonstrate that oral magnesium can protect against acetaminophen-induced liver injury through alterations in the microbiome.

Gut microbiota related response of Oryzias melastigma to combined exposure of polystyrene microplastics and tetracycline

The co-existence of microplastics (MPs) and antibiotics in the coastal environment poses a combined ecological risk. Single toxic effects of MPs or antibiotics on aquatic organisms have been verified, however, the exploration of their combined toxic effects remains limited. Here, foodborne polystyrene microplastics (PS-MPs, 10 μm, 0.1 % w/w in food) and waterborne tetracyclines (TC, 50 μg/L) were used to expose an estuarine fish Oryzias melastigma for four weeks. We found that the aqueous availability of TC was not significantly altered coexisting with MPs. The fish body weight gain was significantly slower in TC alone or combined groups than the control group, consistent with the lower lipid content in livers. The body length gain was significantly inhibited by the combined presence compared to the single exposure. Both exposures led to a shift of gut microbiota composition and diversity. TC and the combined group possessed similar gut microbiota which is distinct from PS-MPs and the control group. The Firmicutes/Bacteroidetes (F/B) ratio in the TC and combined groups were significantly lower compared to the control, while the PS-MPs group showed no significant impact. Metabolomic analysis of the fish liver confirmed the shift of metabolites in specific pathways after different exposures. More, a number of gut microbiota-related metabolites on lipid metabolism was perturbed, which were annotated in arachidonic acid metabolism and linoleic acid metabolism. In all, TC modulates bacterial composition in the fish gut and disturbs their liver metabolites via the gut-liver axis, which led to the slower growth of O. melastigma. More, the adverse impact was aggravated by the co-exposure to foodborne PS-MPs.

Blood Serum and Drainage Microbial and Mitochondrial Metabolites in Patients after Surgery for Pancreatic Cancer

Pancreatic cancer (PC) has the highest mortality rate of all major cancers in the world despite improvements in clinical care and an understanding of the biology of pancreatic cancer. A study of 64 patients with verified pancreatic cancer who underwent surgery was included. Sampling was carried out at three points: before surgery and on days 1-3 after surgery and 5-7 days after surgery. Drainage fluid collection was taken from the drains installed intraoperatively one day after surgery. Tyrosine and phenylalanine metabolites and two mitochondrial metabolites, namely succinic and fumaric acids, were identified and quantified by GC-MS in the serum of healthy donors and patients. Differences in the metabolomic profile were found between the patients and healthy people. A statistically significant decrease in the level of p-hydroxyphenyllactic acid (p-HPhLA), the amount of sum 3 sepsis-associated metabolites (Σ 3AMM), as well as fumaric and succinic acids in patients was observed. It was also noted that p-hydroxyphenyllactic acid in the preoperative period may be considered as a predictor of complications and longer postoperative recovery.