Significant Succession of Intestinal Bacterial Community and Function During the Initial 72 Hours of Acute Pancreatitis in Rats

Amuc_1100 pretreatment alleviates acute pancreatitis in a mouse model through regulating gut microbiota and inhibiting inflammatory infiltration

Amuc_1100 is a membrane protein from Akkermansia muciniphila, which has been found to play a role in host immunological homeostasis in the gastrointestinal tract by activating TLR2 and TLR4. In this study we investigated the effects and underlying mechanisms of Amuc_1100 on acute pancreatitis (AP) induced in mice by intraperitoneal injection of caerulein and lipopolysaccharide (LPS). The mice were treated with the protein Amuc_1100 (3 μg, i.g.) for 20 days before caerulein injection. Cecal contents of the mice were collected for 16S rRNA sequencing. We found that pretreatment with Amuc_1100 significantly alleviated AP-associated pancreatic injury, reduced serum amylase and lipase. Amuc_1100 pretreatment significantly inhibited the expression of proinflammatory cytokines (TNF-α, IL-1β, IFN-γ and IL-6) in spleen and pancreas through inhibiting NF-κB signaling pathway. Moreover, Amuc_1100 pretreatment significantly decreased the inflammatory infiltration, accompanied by the reduction of Ly6C+ macrophages and neutrophils in the spleen of AP mice. Gut microbiome analysis showed that the abundance of Bacteroidetes, Proteobacteria, Desulfobacterota and Campilobacterota was decreased, while the proportion of Firmicutes and Actinobacteriota was increased in AP mice pretreated with Amuc_1100. We further demonstrated that Amuc_1100 pretreatment restored the enrichment of tryptophan metabolism, which was mediated by intestinal flora. These results provide new evidence that Amuc_1100 lessens the severity of AP through its anti-inflammatory properties with a reduction of macrophages and neutrophil infiltration, as well as its regulation of the composition of intestinal flora and tryptophan metabolism.

Complementary yet divergent effects of exercise and an exercise mimetic on microbiome in high-fat diet-induced obesity

Exercise is beneficial for obesity, partially through increased mitochondrial activity and raised nicotinamide adenine dinucleotide (NAD), a coenzyme critical for mitochondrial function and metabolism. Recent work has shown that increasing the availability of NAD through pharmacological means improves metabolic health in rodent models of diet-induced obesity and that the effect of these supplements when administered orally may be modulated by the gut microbiome. The gut microbiome is altered by both diet and exercise and is thought to contribute to some aspects of high-fat diet-induced metabolic dysfunction. We examined the independent and combined effects of treadmill exercise and nicotinamide mononucleotide (NMN) supplementation on the gut microbiome of female C57Bl6/J mice chronically fed a high-fat diet. We showed that 8 wk of treadmill exercise, oral-administered NMN, or combined therapy exert unique effects on gut microbiome composition without changing bacterial species richness. Exercise and NMN exerted additive effects on microbiota composition, and NMN partially or fully restored predicted microbial functions, specifically carbohydrate and lipid metabolism, to control levels. Further research is warranted to better understand the mechanisms underpinning the interactions between exercise and oral NAD+ precursor supplementation on gut microbiome.NEW & NOTEWORTHY Exercise and NAD+ precursor supplementation exerted additive and independent effects on gut microbiota composition and inferred function in female mice with diet-induced obesity. Notably, combining exercise and oral nicotinamide mononucleotide supplementation restored inferred microbial functions to control levels, indicating that this combination may improve high-fat diet-induced alterations to microbial metabolism.

The Role of the Gut Microbiome in the Development of Acute Pancreatitis

With the explosion research on the gut microbiome in the recent years, much insight has been accumulated in comprehending the crosstalk between the gut microbiota community and host health. Acute pancreatitis (AP) is one of the gastrointestinal diseases associated with significant morbidity and subsequent mortality. Studies have elucidated that gut microbiota are engaged in the pathological process of AP. Herein, we summarize the major roles of the gut microbiome in the development of AP. We then portray the association between dysbiosis of the gut microbiota and the severity of AP. Finally, we illustrate the promises and challenges that arise when seeking to incorporate the microbiome in acute pancreatitis treatment.

Current status and advancements in research of gut microecology in acute pancreatitis

Acute pancreatitis (AP) is one of the most common acute abdominal conditions in clinical practice, with increasing incidence and substantial healthcare burden. In recent years, substantial research with high-throughput sequencing technologies has revealed the imbalance between beneficial and pathogenic microbiomes as well as their metabolites during the clinical course of AP. Furthermore, disruption of the intestinal barrier and microbial translocation have been identified as important factors exacerbating systemic inflammatory response and subsequent infectious complications in AP. Maintaining a stable gastrointestinal microecology in patients may help prevent gut-derived infection and attenuate the "second hit" of inflammation induced by AP, thereby improving patient outcomes. This article provides a systematic review of the role of intestinal microbiota and microbial metabolites in the progression of AP, as well as potential therapeutic strategies, in order to offer insights into the understanding of AP pathogenesis and the identification of novel therapeutic targets.

The Effect of Short-Term Consumption of Lactic Acid Bacteria on the Gut Microbiota in Obese People

Obesity is a problem of modern health care that causes the occurrence of many concomitant diseases: arterial hypertension, diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular diseases. New strategies for the treatment and prevention of obesity are being developed that are based on using probiotics for modulation of the gut microbiota. Our study aimed to evaluate the bacterial composition of the gut of obese patients before and after two weeks of lactic acid bacteria (Lactobacillus acidophilus, Lactiplantibacillus plantarum, Limosilactobacillus fermentum, and Lactobacillus delbrueckii) intake. The results obtained showed an increase in the number of members of the phylum Actinobacteriota in the group taking nutritional supplements, while the number of phylum Bacteroidota decreased in comparison with the control group. There has also been an increase in potentially beneficial groups: Bifidobacterium, Blautia, Eubacterium, Anaerostipes, Lactococcus, Lachnospiraceae ND3007, Streptococcus, Escherichia-Shigella, and Lachnoclostridium. Along with this, a decrease in the genera was demonstrated: Faecalibacterium, Pseudobutyrivibrio, Subdoligranulum, Faecalibacterium, Clostridium sensu stricto 1 and 2, Catenibacterium, Megasphaera, Phascolarctobacterium, and the Oscillospiraceae NK4A214 group, which contribute to the development of various metabolic disorders. Modulation of the gut microbiota by lactic acid bacteria may be one of the ways to treat obesity.

The gut-lung axis in severe acute Pancreatitis-associated lung injury: The protection by the gut microbiota through short-chain fatty acids

The role of gut microbiota in regulating the intestinal homeostasis, as well as the pathogenesis of severe acute pancreatitis-associated lung injury (PALI) is widely recognized. The bioactive functions of metabolites with small molecule weight and the detail molecular mechanisms of PALI mediated by "gut-lung axis" have gradually raised the attentions of researchers. Several studies have proved that short-chain fatty acids (SCFAs) produced by gut microbiome play crucial roles and varied activities in the process of PALI. However, relevant reviews reporting SCFAs in the involvement of PALI is lacking. In this review, we firstly introduced the synthetic and metabolic pathways of SCFAs, as well as the transport and signal transduction routes in brief. Afterwards, we focused on the possible mechanisms and clues of SCFAs to participate in the fight against PALI which referred to the inhibition of pathogen proliferation, anti-inflammatory effects, enhancement of intestinal barrier functions, and the maintenance and regulation of immune homeostasis via pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). In addition, the latest reported pathological and physiological mechanisms of the gut-lung axis involved in PALI were reviewed. Finally, we summarized the potential therapeutic interventions of PALI by targeting SCFAs, including dietary fiber supplementation, direct supplementation of SCFAs/prebiotics/probiotics, and drugs administration, which is expected to provide new sights for clinical use in the future.