Coordination-driven assembly of catechol-modified chitosan for the kidney-specific delivery of salvianolic acid B to treat renal fibrosis

Kidney-specific delivery is critically important for the treatment of renal fibrosis with drugs such as salvianolic acid B (Sal B). Here we report a kidney-specific nanocomplex formed by the coordination-driven assembly of catechol-modified low molecular weight chitosan (HCA-Chi), calcium ions and Sal B. The prepared HCA-Chi-Ca-Sal B (HChi-Ca-Sal B) nanocomplex reversed the TGF-β1-induced epithelial-mesenchymal transition (EMT) in HK-2 cells. In vivo imaging demonstrated a kidney-specific biodistribution of the nanocomplex. The anti-fibrosis effect of HChi-Ca-Sal B was tested in a mouse model of unilateral ureteral obstruction (UUO). Significant attenuation of the morphological lesions and the levels of extracellular matrix (ECM) proteins in the tubulointerstitium was observed in mice treated with HChi-Ca-Sal B, suggesting that the nanocomplex was able to prevent fibrosis better than the treatment with free Sal B. It was concluded that the HChi-Ca-Sal B nanocomplex showed a specific renal targeting capacity and could be utilized to enhance Sal B delivery for treating renal fibrosis.