Introduction Low-dose aspirin (LDA)-associated small intestinal injury has been suggested to be associated with gut microbiota dysbiosis. The probiotic Lactobacillus paragasseri OLL2716 (LG21) mitigates LDA-induced injury; however, its mechanisms of action on gut microbiota remain unclear. Methods Participants were assigned to the control, acid-suppressive agents (ASAs)-, and ASAs+LDA-treated groups. All subjects consumed yogurt containing LG21 twice daily for 6 weeks. Ileal lavage and fecal microbiota were analyzed once (at the baseline), and twice (at the baseline and post-intervention), respectively. Results In ileal lavage at the baseline, the family Enterobacteriaceae showed a higher abundance in the ASAs+LDA group than in the control and ASAs groups. A tendency toward increased Enterobacteriaceae abundance was also observed in the feces of the ASAs group; however, it was completely restored to the levels comparable to the control group after LG21 treatment. At the baseline in the fecal microbiota, beta diversity differed significantly between the control and ASAs groups, and between the control and ASAs+LDA groups; whereas, no significant differences were observed among the groups after LG21 intervention. Increased Streptococcaceae and Bacteroidaceae abundances in the ASAs-treated groups at the baseline were also restored after LG21 intervention. Conclusion Increased Enterobacteriaceae abundance was found in both ileal lavage of the ASAs+LDA group and feces of the ASAs group. This increase in the abundance of potentially pathogenic bacteria was restored by a probiotic LG21 strain. These findings suggest that LG21 may modulate gut microbiota, particularly Enterobacteriaceae, which could be associated with its beneficial effects on LDA-induced small bowel injury.

Background/Aims Evidence-based pharmacological options for irritable bowel syndrome with diarrhea (IBS-D) remain limited, and complementary approaches are of interest. We evaluated the real-world effectiveness of hangeshashinto (TJ-14), ramosetron, and their combination in patients with IBS-D or mixed-type IBS (IBS-M). METHODS This retrospective observational pilot study included 56 patients with IBS-D/IBS-M treated for 4 weeks with ramosetron (n=12), hangeshashinto (n=31), or combination therapy (n=13). Symptoms were assessed at baseline and week 4 using the Izumo scale. Within-group changes were examined using nonparametric tests. To address baseline imbalances, pairwise propensity score analyses were performed using Average Treatment effect on the Treated (ATT) weighting with weighted outcome regression adjusting for pretreatment Izumo scores and prespecified covariates. RESULTS All groups showed improvement in Izumo symptom scores over 4 weeks. In ATT-weighted analyses, follow-up Izumo scores were comparable between hangeshashinto and ramosetron (adjusted mean difference [Hangeshashinto - Ramosetron] -0.269, 95% CI -1.402 to 0.863). Combination therapy was associated with lower follow-up scores than ramosetron alone (adjusted mean difference [Combination - Ramosetron] -1.849, 95% CI -3.571 to -0.127), while the comparison with hangeshashinto alone did not reach statistical significance (adjusted mean difference [Combination - Hangeshashinto] -0.845, 95% CI -1.763 to 0.074). Higher pretreatment Izumo scores were independently associated with greater improvement. CONCLUSION In this exploratory real-world analysis, hangeshashinto showed short-term symptom improvement comparable to ramosetron, and adding hangeshashinto to ramosetron was associated with lower follow-up symptom scores than ramosetron monotherapy. Prospective studies are warranted to confirm comparative effectiveness and identify patients most likely to benefit.