Upregulation of neurotrophins and transforming growth factor-β expression in the bladder may lead to nerve hyperplasia and fibrosis in patients with severe ketamine-associated cystitis.

Our findings indicate upregulation of neurotrophins, TGF-β, and activation of the cell proliferation kinases plays an important role in nerve hyperplasia and fibrosis mechanisms in severe KC bladders. The neurotrophins and TGF-β interact as cause and effect, leading to bladder hypersensitivity and fibrosis in severe KC.