Dysbiosis in the Human Microbiome of Cholangiocarcinoma

Metformin facilitates anti-PD-L1 efficacy through the regulation of intestinal microbiota

Metformin is a synthetic biguanide proven to have beneficial effects against various human diseases. Research has confirmed that metformin exerts its effects by regulating the composition of intestinal microbiota. The composition of intestinal microbiota influences the efficacy of anti-PD-L1 immunotherapy. We assume that the regulation of metformin on intestinal microbiota could enhance the therapeutic efficiency of anti-PD-L1 antibodies. In Lewis lung cancer-bearing C57BL/6J mice, we find that metformin enhances PD-L1 antibody efficacy mainly depending on the existence of gut microbiota, and metformin increases the anti-tumor immunity through modulation of intestinal microbiota and affects the integrity of the intestinal mucosa. Antibiotic depletion of gut microbiota abolished the combination efficacy of PD-L1 antibody and metformin, implying the significance of intestinal microbiota in metformin's antitumor action. Combining anti-PD-L1 antibody with metformin provoked tumor necrosis by causing increased CD8 T-cell infiltration and IFN-γ expression. In conclusion, metformin could be employed as a microecological controller to prompt antitumor immunity and increase the efficacy of anti-PD-L1 antibodies. Our study provided reliable evidence that metformin could be synergistically used with anti-PD-L1 antibody to enhance the anti-cancer effect.

A Novel Bifidobacterium/Klebsiella Ratio in Characterization Analysis of the Gut and Bile Microbiota of CCA Patients

Cholangiocarcinoma (CCA) is a serious health problem worldwide. The gut and bile microbiota have not been clearly characterized in patients with CCA, and better noninvasive diagnostic approaches for CCA need to be established. The aim of this study was to investigate the characteristics of the gut and bile microbiota in CCA patients. Forty-two CCA patients and 16 healthy normal controls (HNCs) were enrolled. DNA was extracted from fecal and bile samples and subjected to 16S rRNA gene analysis. We found that there were significant differences in the species diversity, structure, and composition of the microbial communities between the CCA group and the HNC grouAt the phylum level, compared with that in the HNC group, the relative abundance of Firmicutes and Actinobacteriota was significantly decreased in the CCA group, whereas Proteobacteria and Bacteroidota were significantly enriched. The Firmicutes/Bacteroidota (F/B) ratio significantly decreased in the CCA group compared to the HNC grouThe relative abundance of Klebsiella in the CCA group was significantly higher than that in the HNC group, while the relative abundance of Bifidobacterium was significantly decreased. The Bifidobacterium/Klebsiella (B/K) ratio was established as a novel biomarker and was found to be significantly decreased in the CCA group compared with the HNC grouOur findings provide evidence supporting the use of Klebsiella and Bifidobacterium as noninvasive intestinal microbiomarkers for improving the diagnosis of CCA.

Oral Pathogenic Bacteria and the Oral-Gut-Liver Axis: A New Understanding of Chronic Liver Diseases

Liver diseases have long been a prevalent cause of morbidity and mortality, and their development and progression involve multiple vital organs throughout the body. Recent studies on the oral-gut-liver axis have revealed that the oral microbiota is associated with the pathophysiology of chronic liver diseases. Since interventions aimed at regulating oral biological disorders may delay the progress of liver disease, it is crucial to better comprehend this process. Oral bacteria with potential pathogenicity have been extensively studied and are closely related to several types of chronic liver diseases. Therefore, this review will systemically describe the emerging role of oral pathogenic bacteria in common liver diseases, including alcoholic liver disease (ALD), non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver disease (NAFLD), cirrhosis, autoimmune liver diseases (AILD), and liver cancer, and bring in new perspectives for future research.

Interplay between the Human Microbiome and Biliary Tract Cancer: Implications for Pathogenesis and Therapy

Biliary tract cancer, encompassing intrahepatic and extrahepatic cholangiocarcinoma as well as gallbladder carcinoma, stands as a prevalent malignancy characterized by escalating incidence rates and unfavorable prognoses. The onset of cholangiocarcinoma involves a multitude of risk factors and could potentially be influenced by microbial exposure. The human microbiome, encompassing the entirety of human microbial genetic information, assumes a pivotal role in regulating key aspects such as host digestion, absorption, immune responses, and metabolism. The widespread application of next-generation sequencing technology has notably propelled investigations into the intricate relationship between the microbiome and diseases. An accumulating body of evidence strongly suggests a profound interconnection between biliary tract cancer and the human microbiome. This article critically appraises the existing evidence pertaining to the microbiome milieu within patients afflicted by biliary tract cancer. Furthermore, it delves into potential mechanisms through which dysregulation of the human microbiome could contribute to the advancement of biliary tract cancer. Additionally, the article expounds on its role in the context of chemotherapy and immunotherapy for biliary tract cancer.

Gut Microbiota in Diagnosis, Therapy and Prognosis of Cholangiocarcinoma and Gallbladder Carcinoma-A Scoping Review

Cancers of the biliary tract are more common in Asia than in Europe, but are highly lethal due to delayed diagnosis and aggressive tumor biology. Since the biliary tract is in direct contact with the gut via the enterohepatic circulation, this suggests a potential role of gut microbiota, but to date, the role of gut microbiota in biliary tract cancers has not been elucidated. This scoping review compiles recent data on the associations between the gut microbiota and diagnosis, progression and prognosis of biliary tract cancer patients. Systematic review of the literature yielded 154 results, of which 12 studies and one systematic review were eligible for evaluation. The analyses of microbiota diversity indices were inconsistent across the included studies. In-depth analyses revealed differences between gut microbiota of biliary tract cancer patients and healthy controls, but without a clear tendency towards particular species in the studies. Additionally, most of the studies showed methodological flaws, for example non-controlling of factors that affect gut microbiota. At the current stage, there is a lack of evidence to support a general utility of gut microbiota diagnostics in biliary tract cancers. Therefore, no recommendation can be made at this time to include gut microbiota analyses in the management of biliary tract cancer patients.

Interventional effects of oral microecological agents on perioperative indicators of colorectal cancer: a meta-analysis

Purpose

To investigate the efficacy of the application of microecological agents in patients with perioperative colorectal cancer.

Methods

The seven electronic databases including PubMed, Cochrane Library, Excerpt Medica Database (Embase), Web of Science (WOS), Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), and Wan-fang Database were systematically searched for eligible studies from 2000 to February 2023.

Results

A total of 38 randomized controlled clinical trials were included in this study, with a total of 1765 patients in the microecological preparation group and 1769 patients in the control group. All data were analyzed using Review Manager 5.4 and R 4.2.2 software. Meta-analysis showed that in the perioperative period of colorectal cancer, the microecological agents group reduced patients' adverse drug reactions, improved intestinal flora with Lactobacillus (SMD, 3.0858, [2.0197; 4.1520], p< 0. 0001), Bifidobacterium (SMD, 2.1551, [1.6145; 2.6956], p< 0.0001) and Escherichia coli (SMD, -1.1393, [-1.6247; -0.6538], p< 0.0001); protection of intestinal mucosal barrier function, endotoxin (SMD, -2.6850 [-4.1399; -1.2301], p=0.0003), DAO (SMD, -2.5916, [-3.4694; -1.7137], p<0.0001) and plasma D-lactate (SMD, -5.4726, [-9.8901; -1.0551], p= 0.0152), reduced inflammatory response, IL-6 (SMD, -3.1279 [-5.7706; -0.4852], p=0.0204) and CRP (SMD, -3.9698 [-7.6296; -0.3100], p=0.0335); improved the immune function of the organism, CD4+ (SMD, 1.5817 [1.0818; 2.0817], p< 0.0001), CD4+/CD8+ (SMD, 1.2938 [0.9693; 1.6183] p< 0.0001) and IgG (SMD, 1.1376 [0.2993; 1.9759] p=0.0078), improved short-term clinical efficacy, ORR (RR, 1.5105 [1.2306; 1.8541], p< 0.0001) and DCR (RR, 0.3896 [0.2620; 0.5795], p< 0.0001).

Conclusion

By increasing the number of beneficial flora such as Lactobacillus and Bifidobacterium and decreasing the number of harmful flora such as Escherichia coli, the micro-ecological preparation group is beneficial in improving the ecological dysregulation in colorectal cancer patients receiving different treatments in the perioperative period. The microecological preparation group was able to reduce many types of adverse drug reactions, such as infections and gastrointestinal discomfort, compared to the control group. The microecological agents also reduced inflammatory responses, decreased the increase in harmful metabolites, enhanced patients' immune function, protected intestinal mucosal barrier function, and improved short-term clinical outcomes.

Systematic review registration

https://inplasy.com/inplasy-2023-4-0051/, identifier INPLASY202340051.

New challenges in cholangiocarcinoma candidates for elective surgery: harnessing the microbiome dysbiosis

BACKGROUND

The gut microbiota, composed by several species of microorganisms, works to preserve the liver-gut homeostasis and plays an important role during digestion and absorption of nutrients, and in the immune response of the host. In this review, we analyzed the influence of microbiota in patients with cholangiocarcinoma (CCA) who were candidates for elective surgery.

METHODS

A literature review was conducted to identify papers that provided empiric evidence to support that the altered microbiota composition (dysbiosis) is related also to CCA development.

RESULTS

Bacteria such as Helicobacter pylori, Helicobacter hepaticus, and Opisthorchis viverrini increase the risk of CCA. The most abundant genera were Enterococcus, Streptococcus, Bacteroides, Klebsiella, and Pyramidobacter in CCA's biliary microbiota. Additionally, levels of Bacteroides, Geobacillus, Meiothermus, and Anoxybacillus genera were significantly higher. An enrichment of Bifidobacteriaceae, Enterobacteriaceae, and Enterococcaceae families has also been observed in CCA tumor tissue. Microbiota is related to postoperative outcomes in abdominal surgery. The combination of caloric restriction diets in liver cancer or CCA increases the effect of the chemotherapy treatment.

CONCLUSION

The correct use of nutrition for microbiota modulation according to each patient's needs could be a therapeutic tool in combination with elective surgery and chemotherapy to diminish side effects and improve prognosis. Further investigations are needed to fully understand the mechanisms by which they are related.

Gut Microbial Profile Changes in Patients with Gallbladder Stones after UDCA/CDCA Treatment

Background: Ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) are used to treat patients with asymptomatic or mildly symptomatic gallstone disease. This study was conducted to evaluate the efficacy of gallbladder (GB) stone dissolution by UDCA/CDCA and the impact of treatment on gut microbial profiles. Methods: Fifteen treatment-naive patients with GB stones were initially included, but two dropped out during the treatment period. UDCA/CDCA was administered for 6 months. Abdominal ultrasonography was performed to evaluate response to treatment. In addition, fecal samples were collected before and after treatment for gut microbiome profiling. Then, 16S ribosomal RNA gene sequencing was carried out on fecal samples obtained before and after treatment, and results were compared with those of forty healthy controls. Results: Eight (62%) of the thirteen evaluable patients treated with UDCA/CDCA responded to treatment (four achieved complete GB stone resolution and four partial dissolution). Taxonomic compositions of fecal samples at the phylum level showed a significantly lower relative abundance of the Proteobacteria phylum in the pre-UDCA/CDCA group than in the healthy control group (p = 0.024). At the genus level, the relative abundances of five bacteria (Faecalibacterium, Roseburia, Lachnospira, Streptococcus, and Alistipes) differed in the control and pre-UDCA/CDCA group. Interestingly, the abundance of Roseburia was restored after 6 months of UDCA/CDCA treatment. Conclusion: Gut microbial dysbiosis was observed in GB stone patients and partially reversed by UDCA/CDCA treatment, which also effectively dissolved GB stones.

Gut microbiome in gastrointestinal cancer: a friend or foe?

The impact of the gut microbiome on host health is becoming increasingly recognized. To date, there is growing evidence that the complex characteristics of the microbial community play key roles as potential biomarkers and predictors of responses in cancer therapy. Many studies have shown that altered commensal bacteria lead to cancer susceptibility and progression in diverse pathways. In this review, we critically assess the data for gut microbiota related to gastrointestinal cancer, including esophageal, gastric, pancreatic, colorectal cancer, hepatocellular carcinoma and cholangiocarcinoma. Importantly, the underlying mechanisms of gut microbiota involved in cancer occurrence, prevention and treatment are elucidated. The purpose of this review is to provide novel insights for applying this understanding to the development of new therapeutic strategies in gastrointestinal cancer by targeting the microbial community.

Utilizing Gut Microbiota to Improve Hepatobiliary Tumor Treatments: Recent Advances

Hepatobiliary tumors, which include cholangiocarcinoma, hepatocellular carcinoma (HCC), and gallbladder cancer, are common cancers that have high morbidity and mortality rates and poor survival outcomes. In humans, the microbiota is comprised of symbiotic microbial cells (10-100 trillion) that belong to the bacterial ecosystem mainly residing in the gut. The gut microbiota is a complicated group that can largely be found in the intestine and has a dual role in cancer occurrence and progression. Previous research has focused on the crucial functions of the intestinal microflora as the main pathophysiological mechanism in HCC development. Intestinal bacteria produce a broad range of metabolites that exhibit a variety of pro- and anticarcinogenic effects on HCC. Therefore, probiotic alteration of the gut microflora could promote gut flora balance and help prevent the occurrence of HCC. Recent evidence from clinical and translational studies suggests that fecal microbiota transplant is one of the most successful therapies to correct intestinal bacterial imbalance. We review the literature describing the effects and mechanisms of the microbiome in the gut in the context of HCC, including gut bacterial metabolites, probiotics, antibiotics, and the transplantation of fecal microbiota, and discuss the potential influence of the microbiome environment on cholangiocarcinoma and gallbladder cancer. Our findings are expected to reveal therapeutic targets for the prevention of hepatobiliary tumors, and the development of clinical treatment strategies, by emphasizing the function of the gut microbiota.

An Insight into the Novel Immunotherapy and Targeted Therapeutic Strategies for Hepatocellular Carcinoma and Cholangiocarcinoma

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) constitute highly malignant forms of primary liver cancers. Hepatocellular and bile duct carcinogenesis is a multiplex process, caused by various genetic and epigenetic alterations, the influence of environmental factors, as well as the implication of the gut microbiome, which was undervalued in the previous years. The molecular and immunological analysis of the above malignancies, as well as the identification of the crucial role of intestinal microbiota for hepatic and biliary pathogenesis, opened the horizon for novel therapeutic strategies, such as immunotherapy, and enhanced the overall survival of cancer patients. Some of the immunotherapy strategies that are either clinically applied or under pre-clinical studies include monoclonal antibodies, immune checkpoint blockade, cancer vaccines, as well as the utilization of oncolytic viral vectors and Chimeric antigen, receptor-engineered T (CAR-T) cell therapy. In this current review, we will shed light on the recent therapeutic modalities for the above primary liver cancers, as well as on the methods for the enhancement and optimization of anti-tumor immunity.