Action of probiotics and nutrients in the management of tregs cells in patients with obesity and cancer: a systematic review

Introduction: In the context of immunomodulation in patients with obesity and cancer, Bifidobacterium is one of the most commonly used probiotics and activates the anti-CTLA-4 antibody, a checkpoint inhibitor that frequently causes autoimmunity in humans undergoing cancer treatment. Immunotherapy enhances the host's immune system to produce antitumor effects, primarily by stimulating Treg cells. Objective: It was to highlight how probiotics and nutrients can stimulate regulatory T cells in patients with obesity and cancer, to immunomodulate and treat these patients. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from April to June 2024 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 137 articles were found, and 39 articles were evaluated in full, and 31 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 27 studies with a high risk of bias and 25 studies that did not meet GRADE and AMSTAR-2. Most studies showed homogeneity in their results, with X2=68.9%>50%. It was concluded that oral administration of butyrate, propionate, and acetate, individually or in combination, led to an increase in the number of Treg cells in the colon. Also, all-trans retinoic acid (atRA), a bioactive form of vitamin A stimulates Treg cells in the human intestine. Probiotics, together with gut microbiota, have been increasingly proposed to improve immune checkpoint blockade treatments against cancer by activating Treg cells.