CNR1 and renal fibrosis: CB1R, as well as endogenous CB1 ligand, is highly expressed in both UUO‐induced renal fibrosis and in kidney biopsies of patients with IgA nephropathy, acute interstitial nephritis, and diabetic nephropathy.[500] In addition, the expression of CB1R is significantly elevated in renal myofibroblasts in response to TGF‐β, which promotes fibrosis.