Crucially, targeted probiotic approaches recapitulate these effects: in adenine-CKD rats, loss of Lactobacillus johnsonii correlates with renal deterioration, while its supplementation restores fecal L. johnsonii, boosts indole-3-aldehyde—and protects via AhR suppression; in PD patients, L. paracasei N1115 shifts GM toward Firmicutes and relieves GI symptoms—pointing to microbiota as both marker and mediator of TCM efficacy (Miao et al., 2024a; Zhou et al., 2024). The gene discussed is AHR; the disease is chronic kidney disease.