To investigate the role of transient receptor potential cation channel subfamily V proteins in the pathogenesis of ketamine cystitis (KC) patients using the correlation of the proteins with the severity of clinical symptoms.

Bladder tissues from 12 patients with severe KC, and 12 patients with mild KC, and 4 asymptomatic control (AC) subjects were analyzed. All patients with severe KC underwent videourodynamic study followed by augmentation enterocystoplasty to increase bladder capacity. Patients with mild KC received conservative treatment after cystoscopic hydrodistention. Bladder specimens were retrieved from partial cystectomy in severe KC, and from bladder biopsies in mild KC. Western Blot was used to examine the expression level of transient receptor potential cation channel subfamily V proteins in severe KC, mild KC and control. The Pearson test was used for correlations between the protein expression level and the clinical characteristics.

The transient receptor potential vanilloid 1 (TRPV1) and TRPV4 are differentially expressed in bladders of KC patients with different severity and control subjects. Compared with mild KC patients and control subjects, TRPV1 and TRPV4 are significantly increased in the bladders from severe KC patients (Figure 1). In Pearson test, the cystometric bladder capacity shows positive correlation with the maximal bladder capacity (Figure 2A). Visual analog scale shows negative correlation with both cystometric bladder capacity and maximal bladder capacity (Figure 2B).

This study demonstrated that the pathophysiology of bladder symptoms in patients with KC might be associated with the increased expressions of TRPV1 and TRPV4.

Increased TRPV1 and TRPV4 expression are seen in bladder form severe KC patients. TRPV1 may contribute to the pathophysiology of bladder pain and TRPV4 may contribute to the pathophysiology of bladder capacity in KC patients.