Onabotulinumtoxina Intradetrusorial Injections and NGF Expression (Onab/A-NGF)

In the last years, botulinum toxin type A (onab/A) has been increasingly used as a treatment option for overactive bladder symptoms in patients affected by either neurogenic and idiopathic detrusor overactivity (DO). How onab/A injected into the detrusor muscle improves overactive bladder symptoms in neurologic patients has been only partially investigated.Some evidence suggested that the neurotoxin probably reduces detrusor muscle contraction blocking detrusor muscle cholinergic innervation. However, recent experimental observations indicated that onab/A determines more complex effects on bladder activity acting on afferent innervations as well as on the efferent one. Only few experimental studies have investigated the activity of onab/A on bladder afferent nervous transmission. Experimental studies in animals showed that Nerve Growth Factor (NGF) elicits increased sensation, urgency and DO. Although there are some evidence on the ability of onab/A to improve DO and to reduce bladder and urinary content of NGF, how onab/A influences NGF expression and the expression of TrKa, p75 and TRPV1 receptors is still unclear. The hypothesis is that onab/A reduces NGF bladder tissue levels and in the same time it modulates the gene expression of NGF associated receptors (TrkA, p75 and TRPV1).