Natural intestinal metabolite xylitol reduces BRD4 levels to mitigate renal fibrosis

Renal fibrosis is a typical pathological change from chronic kidney disease (CKD) to end-stage renal failure, which presents significant challenges in prevention and treatment. The progression of renal fibrosis is closely associated with the "gut-kidney axis," therefore, although clinical intervention to modulate the "gut-kidney axis" imbalance associated with renal fibrosis brings hope for its treatment. In this study, we first identified the close relationship between renal fibrosis development and the intestinal microenvironment through fecal microtransplantation and non-absorbable antibiotics experiments. Then, we analyzed the specific connection between the intestinal microenvironment and renal fibrosis using microbiomics and metabolomics, screening for the differential intestinal metabolite. Potential metabolite action targets were initially identified through network simulation of molecular docking and further verified by molecular biology experiment. We used flow cytometry, TUNEL apoptosis staining, immunohistochemistry, and Western blotting to assess renal injury and fibrosis extent, exploring the potential role of gut microbial metabolite in renal fibrosis development. We discovered that CKD-triggered alterations in the intestinal microenvironment exacerbate renal injury and fibrosis. When metabolomic analysis was combined with experiments in vivo, we found that the differential metabolite xylitol delays renal injury and fibrosis development. We further validated this hypothesis at the cellular level. Mechanically, bromodomain-containing protein 4 (BRD4) protein exhibits strong binding with xylitol, and xylitol alleviates renal fibrosis by inhibiting BRD4 and its downstream transforming growth factor-β (TGF-β) pathway. In summary, our findings suggest that the natural intestinal metabolite xylitol mitigates renal fibrosis by inhibiting the BRD4-regulated TGF-β pathway.

Plasma exchange plus glucocorticoids in the treatment of immune checkpoint inhibitor-induced myocarditis: A case series and review

Immune checkpoint inhibitors (ICIs), including antiprogrammed cell-death (PD)-1/anti-PD-ligand (PDL-1) monoclonal antibodies, are effective at improving the prognosis of patients with cancer. Among immune-related adverse events, myocarditis associated with anti-PD-1/anti-PD-L1 antibodies is rare but lacks effective treatment and mortality is very high. In this study, the authors extracted data from the previous 8 years from electronic medical records housed in the hospital information system to identify patients hospitalized with myocarditis putatively caused by anti-PD-1/anti-PD-L1 tumor therapy. Clinical data from these patients are reported. Four patients who developed myocarditis after undergoing treatment with anti-PD-1/anti-PD-L1 antibodies for malignant tumors, all of whom responded favorably to therapy consisting of plasma exchange and glucocorticoids for myocarditis, and all patients improved and were discharged from hospital. Plasma exchange plus systemic glucocorticoids may be effective for treating anti-PD-1/anti-PD-L1 antibody-induced myocarditis in patients with cancer.