Probiotics and Probiotic-like Agents against Chemotherapy-Induced Intestinal Mucositis: A Narrative Review

Vitamins and fatty acids against chemotherapy-induced intestinal mucositis

Chemotherapy has allowed an increase in cancer survivorship, but it causes important adverse effects. Mucositis affecting the gastrointestinal tract is one of the main problems acutely caused by many antineoplastic drugs, such as 5-fluorouracil or methotrexate. Mucositis may cause pain, diarrhea, anorexia, weight loss, systemic infections and even death. This narrative review focuses on intestinal mucositis and the role that some nutraceuticals, namely vitamins (both lipid- and water-soluble) as well as fatty acids (FAs) and lipid-based products, can have in it. In preclinical (cell cultures, animal models) and/or human studies, vitamins A, D, E, B2, B9 and C, omega-3 long-chain FAs (eicosapentaenoic, docosahexaenoic, conjugated linoleic acid), short-chain FAs (mainly butyrate), medium-chain FAs (capric acid), and different lipid-based products (emu oil, extra-virgin olive oil, lipid replacement therapy), enriched in beneficial FAs and natural antioxidants, were shown to exert beneficial effects (both preventative and palliative) against chemotherapy-induced intestinal mucositis. Although the exact mechanisms of action involved in these effects are not yet well known, our review highlights the interest of investigating on diet and nutrition to implement scientifically robust strategies to improve protection of cancer patients against chemotherapy-induced adverse effects.

Disturbance of bile acids profile aggravates the diarrhea induced by capecitabine through inhibiting the Wnt/β-catenin pathway

INTRODUCTION

Diarrhea is the primary dose-limiting side effect of capecitabine(Cap) hindering its clinical application, but the mechanism is unclear. Clarifying this mechanism may enhance the patient compliance and improve the treatment outcome.

OBJECTIVES

To assess if the endogenous metabolic profile could prodict the diarrhea induced by Cap and explore and validate underlying mechanisms.

METHODS

Untargeted and targeted bile acids(BAs) metabolomics were performed to analyzed the metabolic profile of baseline samples from colorectal cancer(CRC) patients and the association with the diarrhea induced by Cap was assessed. The toxicity of BAs and Cap and its metabolites alone or their combinations to the human normal intestinal epithelial cell(HIEC) was assessed, and the key genes that mediated the BAs-enhanced toxicity of Cap were discovered by RNA-seq and then validated. A mouse model with high exposure levels of BAs was constructed and then treated with Cap to verify the Cap-induced diarrhea enhanced by BAs.

RESULTS

The baseline endogenous metabolic profile showed obviously difference between diarrhea and non-diarrhea CRC patients, and the differential metabolites mainly enriched in BAs metabolism; the deoxycholic acid(DCA) and lithocholic acid(LCA) were selected to be the key BAs that enhanced the toxicity of Cap metabolite 5-FU to the HIEC cell; the DCA and LCA could inhibit the Wnt/β-catenin signaling pathway, which then suppressed the P-glycoprotein and increased the exposure level of 5-FU in the HIEC cell. The results of animal experiment verified that the excessive DCA and LCA could aggravate the Cap-induced diarrhea through inhibiting Wnt/β-catenin-P-glycoprotein pathway.

CONCLUSIONS

The disordered BAs metabolic profile showed close relationship with diarrhea induced by Cap, and excessive DCA and LCA were proved to be the key BAs, which could aggravate the Cap-induced diarrhea through inhibiting Wnt/β-catenin-P-glycoprotein pathway.

Advancements in the impact of human microbiota and probiotics on leukemia

The human gut microbiota is a complex ecosystem that plays a crucial role in promoting the interaction between the body and its environment. It has been increasingly recognized that the gut microbiota has diverse physiological functions. Recent studies have shown a close association between the gut microbiota and the development of certain tumors, including leukemia. Leukemia is a malignant clonal disease characterized by the uncontrolled growth of one or more types of blood cells, which is the most common cancer in children. The imbalance of gut microbiota is linked to the pathological mechanisms of leukemia. Probiotics, which are beneficial microorganisms that help maintain the balance of the host microbiome, play a role in regulating gut microbiota. Probiotics have the potential to assist in the treatment of leukemia and improve the clinical prognosis of leukemia patients. This study reviews the relationship between gut microbiota, probiotics, and the progression of leukemia based on current research. In addition, utilizing zebrafish leukemia models in future studies might reveal the specific mechanisms of their interactions, thereby providing new insights into the clinical treatment of leukemia. In conclusion, further investigation is still needed to fully understand the accurate role of microbes in leukemia.

Advancements in understanding the role of intestinal dysbacteriosis mediated mucosal immunity in IgA nephropathy

IgA nephropathy, presently recognized as the foremost primary glomerular disorder, emerges as a principal contributor to renal failure globally, with its pathogenesis yet to be fully elucidated. Extensive research has highlighted the critical role of gut microbiome in the onset and progression of IgA nephropathy, underscoring its importance in accurately delineating the disease's etiology. For example, gut microbiome dysbacteriosis can lead to the production of nephritogenic IgA1 antibodies, which form immune complexes that deposit in the kidneys, causing inflammation and damage. The gut microbiome, a source of numerous bioactive compounds, interacts with the host and plays a regulatory role in gut-immune axis modulation, earning it the moniker of the "second brain." Recent investigations have particularly emphasized a significant correlation between IgA nephropathy and gut microbiome dysbacteriosis. This article offers a detailed overview of the pathogenic mechanisms of IgA nephropathy, specifically focusing on elucidating how alterations in the gut microbiome are associated with anomalies in the intestinal mucosal system in IgA nephropathy. Additionally, it describes the possible influence of gut microbiome on recurrent IgA nephropathy following kidney transplantation. Furthermore, it compiles potential therapeutic interventions, offering both theoretical and practical foundations for the management of IgA nephropathy. Lastly, the challenges currently faced in the therapeutic approaches to IgA nephropathy are discussed.

From the Gut to the Brain: The Role of Enteric Glial Cells and Their Involvement in the Pathogenesis of Parkinson's Disease

The brain-gut axis has been identified as an important contributor to the physiopathology of Parkinson's disease. In this pathology, inflammation is thought to be driven by the damage caused by aggregation of α-synuclein in the brain. Interestingly, the Braak's theory proposes that α-synuclein misfolding may originate in the gut and spread in a "prion-like" manner through the vagus nerve into the central nervous system. In the enteric nervous system, enteric glial cells are the most abundant cellular component. Several studies have evaluated their role in Parkinson's disease. Using samples obtained from patients, cell cultures, or animal models, the studies with specific antibodies to label enteric glial cells (GFAP, Sox-10, and S100β) seem to indicate that activation and reactive gliosis are associated to the neurodegeneration produced by Parkinson's disease in the enteric nervous system. Of interest, Toll-like receptors, which are expressed on enteric glial cells, participate in the triggering of immune/inflammatory responses, in the maintenance of intestinal barrier integrity and in the configuration of gut microbiota; thus, these receptors might contribute to Parkinson's disease. External factors like stress also seem to be relevant in its pathogenesis. Some authors have studied ways to reverse changes in EGCs with interventions such as administration of Tryptophan-2,3-dioxygenase inhibitors, nutraceuticals, or physical exercise. Some researchers point out that beyond being activated during the disease, enteric glial cells may contribute to the development of synucleinopathies. Thus, it is still necessary to further study these cells and their role in Parkinson's disease.

Comprehensive probiogenomics analysis of the commensal Escherichia coli CEC15 as a potential probiotic strain

BACKGROUND

Probiotics have gained attention for their potential maintaining gut and immune homeostasis. They have been found to confer protection against pathogen colonization, possess immunomodulatory effects, enhance gut barrier functionality, and mitigate inflammation. However, a thorough understanding of the unique mechanisms of effects triggered by individual strains is necessary to optimize their therapeutic efficacy. Probiogenomics, involving high-throughput techniques, can help identify uncharacterized strains and aid in the rational selection of new probiotics. This study evaluates the potential of the Escherichia coli CEC15 strain as a probiotic through in silico, in vitro, and in vivo analyses, comparing it to the well-known probiotic reference E. coli Nissle 1917. Genomic analysis was conducted to identify traits with potential beneficial activity and to assess the safety of each strain (genomic islands, bacteriocin production, antibiotic resistance, production of proteins involved in host homeostasis, and proteins with adhesive properties). In vitro studies assessed survival in gastrointestinal simulated conditions and adhesion to cultured human intestinal cells. Safety was evaluated in BALB/c mice, monitoring the impact of E. coli consumption on clinical signs, intestinal architecture, intestinal permeability, and fecal microbiota. Additionally, the protective effects of both strains were assessed in a murine model of 5-FU-induced mucositis.

RESULTS

CEC15 mitigates inflammation, reinforces intestinal barrier, and modulates intestinal microbiota. In silico analysis revealed fewer pathogenicity-related traits in CEC15, when compared to Nissle 1917, with fewer toxin-associated genes and no gene suggesting the production of colibactin (a genotoxic agent). Most predicted antibiotic-resistance genes were neither associated with actual resistance, nor with transposable elements. The genome of CEC15 strain encodes proteins related to stress tolerance and to adhesion, in line with its better survival during digestion and higher adhesion to intestinal cells, when compared to Nissle 1917. Moreover, CEC15 exhibited beneficial effects on mice and their intestinal microbiota, both in healthy animals and against 5FU-induced intestinal mucositis.

CONCLUSIONS

These findings suggest that the CEC15 strain holds promise as a probiotic, as it could modulate the intestinal microbiota, providing immunomodulatory and anti-inflammatory effects, and reinforcing the intestinal barrier. These findings may have implications for the treatment of gastrointestinal disorders, particularly some forms of diarrhea.