Lactobacillus acidophilus KBL409 improves serum indoxyl sulfate via gut microbial changes in a human study

Chronic kidney disease (CKD) is characterized by progressive attenuation of kidney functions, resulting in the accumulation of uremic toxins. Various symptoms for CKD are closely associated with the gut-kidney axis, which represents the interaction between gut microbiota and CKD. In this study, we investigated the effects of Lactobacillus acidophilus (L. acidophilus) KBL409 on uremic toxin concentrations using a multi-center, randomized, double-blind, placebo-controlled study. Participants in the L. acidophilus KBL409 group received a daily capsule containing 1 × 10¹⁰ colony-forming units of L. acidophilus KBL409 or placebo. The per protocol analysis included 34 participants in the L. acidophilus KBL409 group and 30 participants in the placebo group. After 16 weeks, the serum indoxyl sulfate (IS) concentration was significantly lower in the L. acidophilus KBL409 group than in the placebo group (p < 0.05). Additionally, significant reductions in the genera Blautia, Butyricicoccus, Lachnospiraceae UCG-004, and Megamonas were observed in the L. acidophilus KBL409 group. These bacteria exhibited positive correlations with predicted functional genes linked to uremic toxin synthesis pathways, suggesting that L. acidophilus KBL409 reduced serum IS by altering gut microbial compositions. Therefore, L. acidophilus KBL409 could be used as an effective probiotic for improving kidney health through gut microbiota modulation.