*Review* **Therapeutic E**ff**ect of Botulinum Toxin A on Sensory Bladder Disorders—From Bench to Bedside**

**Yuan-Hong Jiang 1,2, Wan-Ru Yu <sup>3</sup> and Hann-Chorng Kuo 1,2,\***


Received: 1 February 2020; Accepted: 6 March 2020; Published: 9 March 2020

**Abstract:** Bladder oversensitivity arises from several different conditions involving the bladder, bladder outlet, systemic or central nervous system diseases. Increase of the bladder sensation results from activation of the sensory receptors in the urothelial cells or suburothelial tissues. Medical treatment targeting the overactive bladder (OAB) or interstitial cystitis (IC) might relieve oversensitive bladder symptoms (frequency, urgency and pain) in a portion of patients, but a certain percentage of patients still need active management. Botulinum toxin A (BoNT-A) has been demonstrated to have anti-inflammatory and antinociceptive effects in bladder sensory disorders and has been shown effective in the reduction of bladder oversensitivity and the increase of functional bladder capacity. For patients with OAB, urgency and urinary incontinence improved, while in patients with IC, bladder pain could be relieved in association with reduction of bladder oversensitivity after BoNT-A intravesical injection. Histological evidence has confirmed the therapeutic mechanism and clinical efficacy of intravesical BoNT-A injection on patients with OAB or IC. Bladder oversensitivity can also be relieved with the instillation of liposome encapsulated BoNT-A or low energy show waves (LESWs), which enable the BoNT-A molecule to penetrate into the urothelium and suburothelial space without affecting the detrusor contractility. Liposome encapsulated BoNT-A or combined LESWs and BoNT-A instillation might be future treatment alternatives for bladder oversensitivity in sensory bladder disorders.

**Keywords:** bladder; sensation; therapy; pathophysiology

**Key Contribution:** This study reviews the main pathophysiology and pharmacological mechanisms of botulinum toxin action on the treatment of sensory bladder disorders.
