Research may yield tailored BPS therapies

Dr. Hanno, a Urology Times editorial consultant, is professor of urology at the University of Pennsylvania, Philadelphia.

In this issue of Urology Times, two articles highlight the search for new treatments for bladder pain syndrome (BPS) and efforts to better quantify treatment results and perhaps better phenotype patients so the individual treatment fits the individual’s disease.

Wang et al at the University of Wisconsin, Madison investigated the effects of a selective cannabinoid receptor 2 agonist, GP1a, in mice with chemical. Treatment with GP1a ameliorated the acrolein-induced changes in the bladder but were blocked by a CB2 antagonist. Animal studies have shown that CB1 mRNA is increased in patients with chronic bladder pain syndromes and CB2 mRNA is increased in rats with bladder inflammation induced by acrolein. Stimulation of cannabinoid receptors reduces afferent activity.

It is likely that CB1 and CB2 receptors located in the bladder participate in the intrinsic control of initiation of afferent stimulus. Those interested in this active area of pharmaceutical research can refer to the review by Tyagi et al (Indian J Urol 2010; 26:26-35) and the report of Waiczak and Cervero (Mol Pain 2011; 7:31).

The search is on for drugs based on cannabis and can be divided into the following four categories: drugs that contain chemicals taken from the marijuana plant, drugs that contain synthetic versions of these naturally occurring chemicals, drugs that contain chemicals similar to those in marijuana but not found in the plant, and drugs that have similar brain pathways but a different mechanism of action.

The finding by Chancellor and Peters that urinary measurement of inflammatory chemokines may offer a noninvasive method for evaluating treatment response to neuromodulation may not only offer an avenue other than symptom relief to gauge whether the treatment is effective or likely to be effective over time, but also serves to identify a group of patients who are likely to benefit from neuromodulation. Not all BPS patients have an active element of inflammation, and those with pelvic pain from confusable disorders like pelvic floor dysfunction may not. Those with higher levels of inflammatory chemokines at baseline perhaps would have a higher likelihood of treatment success with this modality.

It would be interesting to repeat this study using percutaneous tibial nerve stimulation and observing clinical effects as well as urinary marker response.UT

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