Selenium-enriched Bifidobacterium longum DD98 significantly improves the efficacy of Mesalazine and Cyclosporin A in colitis mice

The incidence of ulcerative colitis (UC) is increasing worldwide and therapeutic drugs for UC are limited. Improvement of microbiome composition with the use of probiotics has the potential to increase the therapeutic index of UC drugs. Several lines of evidence suggested that Bifidobacterium significantly improve colitis by restoring the altered gut microbiota in DSS-treated mice, however the adjuvant effect of Bifidobacterium with UC drugs remains unknown. In this study, we tested the adjuvant potential of probiotic selenium-enriched Bifidobacterium Longum DD98 (SeDD98) on Mesalazine and Cyclosporin A (CsA) two medications used in the treatment of UC. We found that SeDD98 significantly improved the efficacy of Mesalazine and CsA in UC. The combination of SeDD98 and CsA showed the strongest efficacy in decreasing colitis histological scores, inflammation, and oxidative stress. Next we demonstrated that the combination of SeDD98 and CsA shifted the gut microbiota composition and increased with higher alpha diversity as well as beneficial bacteria such as Ruminococcaceae_UCG-014 and Lachnospiraceae_NK4A136. In parallel, we assessed if the adjuvant of SeDD98 with CsA had an impact on CsA-induced kidney injury which represents one of the major side effects. We found that SeDD98 significantly improved CsA nephrotoxicity in UC mice. We then validated this observation using chronic kidney disease (CKD) mice induced by CsA administration. These results demonstrated that SeDD98 in combination with CsA was associated with increased efficacy and reduced nephrotoxicity altogether, providing the scientific basis for the adjuvant therapy of probiotics in UC.