A comparative evaluation of the kefir yeast Kluyveromyces marxianus A4 and sulfasalazine in ulcerative colitis: anti-inflammatory impact and gut microbiota modulation.

Although only Saccharomyces boulardii has been studied for ulcerative colitis (UC), probiotic yeasts have immense therapeutic potential. Herein, we evaluated the kefir yeast Kluyveromyces marxianus A4 (Km A4) and its anti-inflammatory effect with sulfasalazine in BALB/c mice with dextran sulfate sodium (DSS)-induced colitis. Oral administration continued for 7 days after the mice were randomly divided into seven groups: control (CON, normal mice administered with saline), DSS-induced colitis mice administered saline (DSS), and DSS-induced colitis mice administered sulfasalazine only (S), Km A4 only (A4), Km A4 plus sulfasalazine (A4 + S), S . boulardii ATCC MYA-796 (Sb MYA-796) only (Sb), and Sb MYA-796 plus sulfasalazine (Sb + S). The β-glucan content of Km A4 was significantly higher than that of Sb MYA-796 ( P < 0.05). Body weight gain (BWG) significantly correlated with colon length, cyclooxygenase-2 ( Cox-2 ) levels, and Bacteroides abundance ( P < 0.05). In colitis-induced mice, the A4 + S group had the lowest histological score (6.00) compared to the DSS group (12.67), indicating the anti-inflammatory effects of this combination. The A4 + S group showed significantly downregulated expression of interleukin ( Il )- 6 , tumor necrosis factor-α ( Tnf-α ), and Cox-2 and upregulated expression of Il-10 and occludin ( Ocln ) compared to the DSS group. Mice treated with A4 + S had enhanced Bacteroides abundance in their gut microbiota compared with the DSS group ( P < 0.05). Bacteroides were significantly correlated with all colitis biomarkers (BWG, colon length, Il-6 , Tnf-α , Il-10 , Cox-2 , and Ocln ; P < 0.05). The anti-inflammatory effects of Km A4 could be attributed to high β-glucan content and gut microbiota modulation. Thus, treatment with Km A4 and sulfasalazine could alleviate UC.