Metagenomic and targeted metabolomic analyses reveal distinct phenotypes of the gut microbiota in patients with colorectal cancer and type 2 diabetes mellitus

Role of gut microbiome in suppression of cancers

The pathogenesis of cancer is closely related to the disruption of homeostasis in the human body. The gut microbiome plays crucial roles in maintaining the homeostasis of its host throughout lifespan. In recent years, a large number of studies have shown that dysbiosis of the gut microbiome is involved in the entire process of cancer initiation, development, and prognosis by influencing the host immune system and metabolism. Some specific intestinal bacteria promote the occurrence and development of cancers under certain conditions. Conversely, some other specific intestinal bacteria suppress the oncogenesis and progression of cancers, including inhibiting the occurrence of cancers, delaying the progression of cancers and boosting the therapeutic effect on cancers. The promoting effects of the gut microbiome on cancers have been comprehensively discussed in the previous review. This article will review the latest advances in the roles and mechanisms of gut microbiome in cancer suppression, providing a new perspective for developing strategies of cancer prevention and treatment.

Gut microbiota regulates hepatic ketogenesis and lipid accumulation in ketogenic diet-induced hyperketonemia by disrupting bile acid metabolism

The ketogenic diet (KD) induces prolonged hyperketonemia, characterized by elevated circulating level of β-hydroxybutyrate. However, the KD can negatively affect host metabolic health by altering the gut microbial community. Despite this, the regulatory effect of the gut microbiota on hepatic ketogenesis and triacylglycerol (TAG) accumulation during a KD remains poorly understood. Here, we hypothesized that the commensal bacterium regulates hepatic lipid metabolism in association with KD-induced hyperketonemia. The KD disrupts the remodeling of the gut microbiota following antibiotic-induced depletion. The capacity for ketogenesis and the severity of TAG accumulation in the liver closely correlated with changes in the gut microbial composition and the up-regulation of hepatic farnesoid X receptor (FXR), peroxisome proliferator-activated receptor alpha (PPARα), and diacylglycerol O-acyltransferase 2 (DGAT2), which were modulated by bile acid metabolism through the gut-liver axis. The commensal bacterium Clostridium perfringens type A is particularly implicated in prolonged hyperketonemia, exacerbating hepatic ketogenesis and steatosis by disrupting secondary bile acid metabolism. The increased conversion of deoxycholic acid to 12-ketolithocholic acid represents a critical microbial pathway during C. perfringens colonization. These findings illuminate the adverse effects of the gut microbiota on hepatic adaptation to a KD and highlight the regulatory role of C. perfringens in ketonic states.

Biliary-intestinal anastomosis leads to alterations in intestinal flora and its flora metabolites and increases the risk of long-term postoperative complications: a case-control study

Objective

Pancreaticoduodenectomy (PD) is a major surgical intervention that encompasses the resection of multiple organs and the reconstruction of the digestive tract, with reconstructive procedures including pancreatico-enteric, bilioenteric, and gastroenteric anastomoses. Prior research has documented a high incidence of long-term complications following PD, which significantly impact patient prognosis and survival, however, the underlying mechanisms remain elusive. Evidence from previous studies suggests that biliary-intestinal anastomosis modifies biliary tract anatomy, altering bile flow into the gut and potentially affecting the gut microbiota and its metabolites. Given the close association between biliary tract infections and alterations in gut microbiota, we hypothesize that changes in intestinal flora and its metabolites post-PD may be a critical factor in the development of long-term complications. The objective of this study is to investigate whether biliary-intestinal anastomosis during PD induces changes in the intestinal microbiota and its metabolites, which in turn may increase the risk of long-term postoperative complications.

Methods

This study included 17 patients who underwent the procedure (group T) and 20 sex- and age-matched controls who did not (group N), patients in group T were stratified into those with (complication group) and without (non-complication group) long-term postoperative complications. Faecal samples were collected from all subjects and DNA was extracted from the samples using 16S rRNA gene sequencing to analyse the composition of the faecal flora and detect flora metabolites.

Results

1. Alpha diversity analysis of the two sample groups indicated a trend towards lower microbial abundance in Group T relative to Group N, however, no significant differences were observed in the Shannon and Simpson diversity indices. 2. At the genus level, Group T patients exhibited markedly higher levels of Escherichia-Shigella, Veillonella, and Enterobacter, while showing significantly lower abundance of Blautia and Bifidobacterium compared to Group N subjects. Analysis of Spearman's correlation and degree of correlation between genera showed a significant negative correlation between Escherichia shigella and Blautia. Veillonella showed a significant positive correlation with both Escherichia shigella and Enterobacter. In addition, Blautia and Bifidobacterium showed a significant positive correlation with each other. 3. Subsequent comparative analysis of the bacterial flora between the complication and non-complication groups revealed a significantly elevated abundance of Escherichia-Shigella in the complication group as compared to the non-complication group. 4. Faecal metabolomic analysis revealed that L-palmitoylcarnitine, arachidic acid and PG 13:0_15:0 were significantly increased in the T group compared to the N group, whereas 3-isopropylmalic acid was significantly decreased in the T group. 5. KEGG pathway analysis identified nine crucial metabolic pathways associated with these microbial shifts: alterations in starch and sucrose metabolism, steroid hormone biosynthesis, caffeine metabolism, the citric acid cycle, riboflavin metabolism, sulfur metabolism, and the biosynthesis of valine, leucine, and isoleucine, as well as pyruvate metabolism and ABC transporter protein pathways.

Conclusion

1. The biliary-intestinal anastomosis, which is performed as part of a pancreaticoduodenectomy, induces significant shifts in the intestinal flora. 2. Increased abundance of Escherichia-Shigella may promote long-term complications after biliary-intestinal anastomosis. 3. Biliary-intestinal anastomosis leads to alterations in the metabolites of the patient's intestinal flora. 4. Intestinal flora and their metabolites in patients after biliary-intestinal anastomosis may contribute to the development of long-term complications through nine metabolic pathways.

Exploring biomarkers and molecular mechanisms of Type 2 diabetes mellitus promotes colorectal cancer progression based on transcriptomics

Type 2 diabetes mellitus (T2DM) has been confirmed as an independent risk factor for colorectal cancer (CRC) in many studies. However, the mechanisms behind T2DM's role in the progression of CRC remain unclear. This study aims to explore the potential biomarkers and molecular mechanisms involved in T2DM-promoted CRC progression. The limma package was used to identify differentially expressed genes in tumor tissue from CRC patients with or without T2DM. The key biological processes were screened by gene ontology and gene set enrichment analysis. A diagnostic model for co-morbidities was constructed by logistic regression model with least absolute shrinkage and selection operator (Lasso) regularization method. The diagnostic performance was assessed by supplementing external datasets to draw ROC curves on the diagnostic model. The diagnostic model was further screened for key genes by prognostic analysis. The relationship of key genes with immune cells and other cells was evaluated by immune infiltration algorithm and single-cell transcription analysis. Drug prediction was performed by cMAP and the obtained drugs were molecularly docked with the key genes. The differentially expressed genes of T2DM-promoted CRC progression were mainly enriched to O-linked glycosylation-related processes. The diagnostic model constructed based on Lasso logistic regression had good diagnostic performance (AUC > 0.8). COX11 was the key gene for co-morbidities: in tumor tissues, COX11 expression was significantly higher than that in normal colon tissues. However, COX11 gene expression was significantly lower in patients with comorbidities than in patients without T2DM in tumor tissue. External datasets confirmed from both mRNA and protein expression levels that low COX11 expression was significantly associated with poor CRC prognosis. Immune infiltration analysis suggested that its expression related to the proportion of M2 macrophages. Single-cell transcriptome analysis revealed a close association of COX11 expression with endothelial cells and macrophages. The top4 drugs predicted bound well to COX11. Our study revealed that the pathogenesis of T2DM-promoted CRC progression related to O-linked glycosylation. We constructed a diagnostic model for T2DM-CRC co-morbidity. Meanwhile, we identified COX11 as a potential immune-related molecular marker closely associated with T2DM-promoted CRC progression. These mechanisms and molecular markers may provide new ideas for further studies of T2DM-promoted CRC progression and contribute to drug discovery for the treatment of co-morbidities.

Analysis of metagenome and metabolome disclosed the mechanisms of Dendrobium officinale polysaccharide on DSS-induced ulcerative colitis-affected mice

Currently, there is no known cause for ulcerative colitis (UC), an inflammatory bowel disease that is difficult to treat. This assay aimed to investigate the protective effects and mechanisms of Dendrobium officinale polysaccharide (DOP) in mice with acute UC induced by dextran sulphate sodium (DSS). We found that DOP could improve weight loss, decrease the disease activity index (DAI), and regulate the release of interleukin 2 (IL-2), IL-4, IL-6, and IL-10 in DSS-induced acute UC mice. Additionally, DOP preserved the integrity of the intestinal barrier in UC mice by increasing goblet cell density and maintaining tight junctions. DOP significantly enhanced total antioxidant capacity (T-AOC), and reduced glutathione (GSH), nitric oxide (NO), and malondialdehyde (MDA) levels in the bloodstream. In terms of serum biochemistry, DOP markedly elevated levels of bilirubin (BIL), alkaline phosphatase (ALP), total bile acid (TBA), creatinine (Crea), and creative kinase isoenzyme (CKMB). Furthermore, DOP increased the relative abundance of Lactobacillales. DOP also improved intestinal health and stimulated the synthesis of potent anti-inflammatory and antiviral substances by regulating the metabolism of purines, prostaglandins, and leukotrienes. Therefore, DOP can be considered a functional dietary supplement for the treatment of UC, as it improves the condition of DSS-induced UC mice.

Gut microbiota and metabolites as predictors of biologics response in inflammatory bowel disease: A comprehensive systematic review

Nonresponse to biologic agents in patients with inflammatory bowel disease (IBD) poses a significant public health burden, and the prediction of response to biologics offers valuable insights for IBD management. Given the pivotal role of gut microbiota and their endogenous metabolites in IBD, we conducted a systematic review to investigate the potential of fecal microbiota and mucosal microbiota and endogenous metabolomic markers as predictors for biotherapy response in IBD patients. A total of 38 studies were included in the review. Following anti-TNF-α treatment, the bacterial community characteristics of IBD patients exhibited a tendency to resemble those observed in healthy controls, indicating an improved clinical response. The levels of endogenous metabolites butyrate and deoxycholic acid were significantly associated with clinical remission following anti-TNF-α therapy. IBD patients who responded well to vedolizumab treatment had higher levels of specific bacteria that produce butyrate, along with increased levels of metabolites such as butyrate, branched-chain amino acids and acetamide following vedolizumab treatment. Crohn's disease patients who responded positively to ustekinumab treatment showed higher levels of Faecalibacterium and lower levels of Escherichia/Shigella. In conclusion, fecal microbiota and mucosal microbiota as well as their endogenous metabolites could provide a predictive tool for assessing the response of IBD patients to various biological agents and serve as a valuable reference for precise drug selection in clinical IBD patients.

Lactobacillus brevis alleviates the progress of hepatocellular carcinoma and type 2 diabetes in mice model via interplay of gut microflora, bile acid and NOTCH 1 signaling

Type 2 diabetes (T2DM) clinically exhibits a higher incidence of hepatocellular carcinoma (HCC), contributing to a lousy prognosis in patients harboring both diseases. Microflora-based therapy draws attention with low side effects. Accumulating evidence shows that Lactobacillus brevis can improve blood glucose and body weight of the T2DM mice model and reduce several cancer incidences. However, the therapeutic effect of Lactobacillus brevis in affecting the prognosis of T2DM+HCC remains unknown. In this study, we aim to explore this question via an established T2DM+HCC mice model. We observed a significant alleviation after the probiotic intervention. Lactobacillus brevis improves blood glucose and insulin resistance and ameliorates Mechanically. Combined with a multi-omics approach including 16SrDNA, GC-MS, and RNA-seq, we identified distinct intestinal microflora composition and metabolites after Lactobacillus brevis intervention. Furthermore, we found that Lactobacillus brevis delayed disease progression by regulating MMP9 and NOTCH 1 signaling pathways, potentially through gut microflora and BA interaction. This study indicates that Lactobacillus brevis may improve the prognosis of T2DM + HCC, providing novel therapeutic opportunities via targeting intestinal flora for patients with T2DM+HCC.