Bile acids as carcinogens in the colon and at other sites in the gastrointestinal system

Exercise, Dietary Habits, and Defecatory Dysfunction in Patients Living with Colorectal Cancer: A Preliminary Quantitative Study

This study investigated the association of exercise and dietary habits with defecatory dysfunction in patients living with colorectal cancer. We recruited 61 adult patients who had undergone surgery within the past 20 years and attended outpatient clinics at designated cancer hospitals in Japan. Defecatory dysfunction was defined as any symptom caused by issues with colon and anal function, including fecal incontinence, evacuation difficulties, frequent stools, diarrhea, and constipation. Exercise and dietary habits were assessed via a quantitative questionnaire survey. Postoperative defecatory dysfunction occurred in all the patients. Multivariate analysis revealed no association between exercise habits and defecatory dysfunction; however, dietary fiber intake ≥4 times a week was associated with frequent stools (adjusted odds ratio, 5.11; 95% confidence interval, 1.10, 23.70). These findings suggest a need to alleviate defecatory dysfunction by improving one's dietary habits. Interventions aimed at alleviating defecatory dysfunction by improving the dietary habits in patients living with colorectal cancer are needed.

Swertiamarin relieves radiation-induced intestinal injury by limiting DNA damage

Radiotherapy is the conventional treatment for pelvic abdominal tumors. However, it can cause some damage to the small intestine and colorectal, which are very sensitive to radiation. Radiation-induced intestinal injury (RIII) affects the prognosis of radiotherapy, causing sequelae of loss of function and long-term damage to patients' quality of life. Swertiamarin is a glycoside that has been reported to prevent a variety of diseases including but not limited to diabetes, hypertension, atherosclerosis, arthritis, malaria, and abdominal ulcers. However, its therapeutic effect and mechanism of action on RIII have not been established. We investigated whether swertiamarin has a protective effect against RIII. In this article, we use irradiator to create cellular and mouse models of radiation damage. Preventive administration of swertiamarin could reduce ROS and superoxide anion levels to mitigate the cellular damage caused by radiation. Swertiamarin also attenuated RIII in mice, as evidenced by longer survival, less weight loss and more complete intestinal barrier. We also found an increase in the relative abundance of primary bile acids in irradiated mice, which was reduced by both FXR agonists and swertiamarin, and a reduction in downstream interferon and inflammatory factors via the cGAS-STING pathway to reduce radiation-induced damage.

Bile Acid Diarrhea Is Associated With an Increased Incidence of Gastrointestinal Cancers

INTRODUCTION

Bile acid diarrhea (BAD) is an underrecognized and socially debilitating disease caused by high concentrations of bile acids in the colon. Bile acids directly and indirectly promote carcinogenesis. In this article, we investigated whether individuals with BAD have an increased risk of gastrointestinal (GI) cancers.

METHODS

By using the Danish health registries, adult individuals with BAD were identified by International Classification of Diseases 10th revision code K90.8 or referral to the diagnostic ⁷⁵selenium-homotaurocholic acid test followed by prescription of a bile acid sequestrant within 365 days (n = 5,245). Age- and sex-matched individuals without BAD were included for comparison (n = 52,450). We analyzed the cumulative incidence of GI cancers after BAD diagnosis and the odds ratios (ORs) of GI cancer 8 and 15 years before BAD diagnosis/matching.

RESULTS

Cumulative incidence of GI cancer 6 years after BAD diagnosis/matching was 1.6% in the BAD group and 1.1% in controls ( P = 0.01). The ORs of total GI cancer 8 and 15 years before BAD diagnosis were 6.16 (5.08-7.48) and 5.19 (4.28-6.29), respectively. Furthermore, 47 individuals with BAD (0.9%) and 250 (0.5%) controls died of GI cancer.

DISCUSSION

This nationwide cohort study indicates an association between BAD and GI cancers. We found both a higher incidence of GI cancer after BAD diagnosis compared with controls and increased OR of GI cancer before BAD diagnosis. Bearing in mind the underdiagnosis of BAD, the delay of BAD diagnosis, and the carcinogenic effect of bile acids, these findings warrant further investigations of the risk of GI cancer in individuals with BAD.

Another renaissance for bile acid gastrointestinal microbiology

The field of bile acid microbiology in the gastrointestinal tract is going through a current rebirth after a peak of activity in the late 1970s and early 1980s. This renewed activity is a result of many factors, including the discovery near the turn of the century that bile acids are potent signalling molecules and technological advances in next-generation sequencing, computation, culturomics, gnotobiology, and metabolomics. We describe the current state of the field with particular emphasis on questions that have remained unanswered for many decades in both bile acid synthesis by the host and metabolism by the gut microbiota. Current knowledge of established enzymatic pathways, including bile salt hydrolase, hydroxysteroid dehydrogenases involved in the oxidation and epimerization of bile acid hydroxy groups, the Hylemon-Bjӧrkhem pathway of bile acid C7-dehydroxylation, and the formation of secondary allo-bile acids, is described. We cover aspects of bile acid conjugation and esterification as well as evidence for bile acid C3-dehydroxylation and C12-dehydroxylation that are less well understood but potentially critical for our understanding of bile acid metabolism in the human gut. The physiological consequences of bile acid metabolism for human health, important caveats and cautionary notes on experimental design and interpretation of data reflecting bile acid metabolism are also explored.

A Case Report and Literature Review of Gastric Stump Carcinoma: An Uncommon Entity Following the Billroth II Procedure

Gastric stump carcinoma is a rare phenomenon and could occur in individuals after a distal gastric resection. Regardless of the surgical approach, it can lead to certain complications. However, the Billroth II gastrojejunostomy procedure has been noted to have some specifically interesting complications due to the anatomical changes it triggers. These changes, such as bacterial overgrowth and enterogastric reflux, can cause metaplasia. We discuss a case of an 81-year-old male with a history of peptic ulcer disease (PUD) status post-Billroth II gastrojejunostomy 30 years prior who presented with a four-day history of bright red blood per rectum. On esophagogastroduodenoscopy (EGD), he was found to have friable, ulcerated mucosa at the anastomosis site. Biopsy results revealed CDX2-positive cells, indicating gastric adenocarcinoma. Although it is well-known that the anatomical changes of gastrojejunostomy will undoubtedly change the microbiome of the stomach, physicians should also be mindful of the more feared complications such as gastric stump carcinoma.

Microbiome in Cancer Development and Treatment

Targeting the microbiome, microbiota-derived metabolites, and related pathways represents a significant challenge in oncology. Microbiome analyses have confirmed the negative impact of cancer treatment on gut homeostasis, resulting in acute dysbiosis and severe complications, including massive inflammatory immune response, mucosal barrier disruption, and bacterial translocation across the gut epithelium. Moreover, recent studies revealed the relationship between an imbalance in the gut microbiome and treatment-related toxicity. In this review, we provide current insights into the role of the microbiome in tumor development and the impact of gut and tumor microbiomes on chemo- and immunotherapy efficacy, as well as treatment-induced late effects, including cognitive impairment and cardiotoxicity. As discussed, microbiota modulation via probiotic supplementation and fecal microbiota transplantation represents a new trend in cancer patient care, aiming to increase bacterial diversity, alleviate acute and long-term treatment-induced toxicity, and improve the response to various treatment modalities. However, a more detailed understanding of the complex relationship between the microbiome and host can significantly contribute to integrating a microbiome-based approach into clinical practice. Determination of causal correlations might lead to the identification of clinically relevant diagnostic and prognostic microbial biomarkers. Notably, restoration of intestinal homeostasis could contribute to optimizing treatment efficacy and improving cancer patient outcomes.