Gut Microbiota Management Research Articles

A High-Salt Diet Exacerbates Liver Fibrosis through Enterococcus-Dependent Macrophage Activation.

People consume more salt than the recommended levels due to poor dietary practices. The effects of long-term consumption of high-salt diets (HSD) on liver fibrosis are unclear. This study aimed to explore the impact of HSD on liver fibrosis. In this study, a carbon tetrachloride (CCL4)-induced liver fibrosis mouse model was used to evaluate fibrotic changes in the livers of mice fed a normal diet (ND) and an HSD. The HSD exacerbated liver injury and fibrosis. Moreover, the protein expression levels of transforming growth factor β (TGF-β), tumor necrosis factor alpha (TNF-α), and monocyte chemoattractant protein 1 (MCP-1) were significantly higher in the HSD group than in the normal group. The proportion of macrophages and activation significantly increased in the livers of HSD-fed mice. Meanwhile, the number of macrophages significantly increased in the small intestinal lamina propria of HSD-fed mice. The levels of profibrotic factors also increased in the small intestine of HSD-fed mice. Additionally, HSD increased the profibrotic chemokines and monocyte chemoattractant levels in the portal vein blood. Further characterization suggested that the HSD decreased the expression of tight junction proteins (ZO-1 and CLDN1), enhancing the translocation of bacteria. Enterococcus promoted liver injury and inflammation. In vitro experiments demonstrated that Enterococcus induced macrophage activation through the NF-κB pathway, thus promoting the expression of fibrosis-related genes, leading to liver fibrogenesis. Similarly, Enterococcus disrupted the gut microbiome in vivo and significantly increased the fibrotic markers, TGF-β, and alpha smooth muscle actin (α-SMA) expression in the liver. IMPORTANCE This study further confirms that Enterococcus induce liver fibrosis in mice. These results indicate that an HSD can exacerbate liver fibrosis by altering the gut microbiota composition, thus impairing intestinal barrier function. Therefore, this may serve as a new target for liver fibrosis therapy and gut microbiota management.

Effect of Prebiotics and Synbiotics Carried by Food over Irritable Bowel Syndrome Symptoms: A Systematic Review

Irritable bowel syndrome (IBS) is a chronic condition that affects 11.2% of the world’s population. The management of gut microbiota using probiotic and synbiotic agents might be a valid alternative to assist in the treatment of IBS. The focus of this study was to evaluate the effects of prebiotic and synbiotic compounds carried by different foods on major symptoms of IBS through a systematic literature review. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and LILACS were accessed during July 2021. The studies included in this review were the ones that tested volunteers older than 16 years of age and were conducted using a randomized, controlled clinical trial. The risk of bias was assessed by using the Cochrane risk-of-bias tool for randomized trials (RoB2). Furthermore, the data found were qualitatively evaluated due to the studies’ differences. Two papers were able to fit the criteria, with a total sample size of 280 participants. No datum was found regarding the use of prebiotics in the treatment of IBS. Synbiotic agents, however, had a positive effect on gastrointestinal symptoms and the participants’ overall bowel satisfaction; however, it was not possible to reach a consensus on which effects. Further studies regarding the use of synbiotics and prebiotics must be carried out to determine which effects are the most significant in the treatment of IBS.

How can probiotic improve irritable bowel syndrome symptoms?

The onset and manifestations of irritable bowel syndrome (IBS) is associated with several factors, and the pathophysiology involves various central and peripheral mechanisms. Most studies indicate that the management of gut microbiota could significantly affect the improvement of subjective disorders in patients with IBS. Numerous clinical trials have assessed the efficacy of probiotics for IBS with controversial conclusions. Several clinical trials have suggested that probiotics can improve global IBS symptoms, while others only improve individual IBS symptoms, such as bloating scores and abdominal pain scores. Only a few clinical trials have found no apparent effect of probiotics on IBS symptoms. Generally, probiotics appear to be safe for patients with IBS. However, the question of which probiotics should be used for certain IBS subtypes remains unresolved. In everyday practice, the dose of the recommended probiotic remains questionable, as well as how long the probiotic should be used in therapy. The use of probiotics in the M subtype and non-classified IBS is particularly problematic, in which combination therapy should be recommended due to the change in symptoms. Therefore, new approaches are needed in the design of clinical studies that should address certain subtypes of IBS.

Gut microbiota in obesity.

Obesity is a major global health problem determined by heredity and environment, and its incidence is increasing yearly. In recent years, increasing evidence linking obesity to the gut microbiota has been reported. Gut microbiota management has become a new method of obesity treatment. However, the complex interactions among genetics, environment, the gut microbiota, and obesity remain poorly understood. In this review, we summarize the characteristics of the gut microbiota in obesity, the mechanism of obesity induced by the gut microbiota, and the influence of genetic and environmental factors on the gut microbiota and obesity to provide support for understanding the complex relationship between obesity and microbiota. At the same time, the prospect of obesity research related to the gut microbiota is proposed.

The Effects of Probiotic Formulation Pretreatment (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) on a Lipopolysaccharide Rat Model

Objective: The role of gut microbiota in the pathogenesis of several neurodegenerative disorders, including Alzheimer’s disease (AD), via the gut–brain axis has recently been demonstrated; hence, modification of the intestinal microbiota composition by probiotic biotherapy could be a therapeutic target for these conditions. The aim of this study was to assess the effects of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) on inflammatory and memory processes in lipopolysaccharide (LPS)-induced rats, one of the animal models used in peripherally induced neuroinflammation and neurodegeneration.Methods: Rats were randomly divided into four groups (Control, LPS, Probiotic + LPS, and Probiotic). All experimental groups were orally administrated maltodextrin (placebo) or probiotic (109 CFU/ml/rat) for 14 consecutive days and then were injected with saline or LPS (1 mg/kg, intraperitoneally [i.p.], single dose) 20 hours later. Memory retention ability and systemic and neuroinflammatory markers were assessed 4 hours after the injections.Results: Systemic exposure to LPS resulted in significant elevation of both the circulating and hippocampal levels of proinflammatory cytokines, which decreased remarkably following probiotic pretreatment. Oral bacteriotherapy with a combination of L. helveticus R0052 and B. longum R0175 also attenuated the decremental effect of LPS on memory through brain-derived neurotrophic factor (BDNF) expression at the molecular level; however, this effect was not significant in the passive avoidance test at the behavioral level.Conclusions: These results suggest that the management of gut microbiota with this probiotic formulation could be a promising intervention to improve neuroinflammation-associated disorders such as AD.