What are the origins and relevance of spontaneous bladder contractions? ICI-RS 2017

Storage phase bladder activity is a counter-intuitive observation of spontaneous contractions. They are potentially an intrinsic feature of the smooth muscle, but interstitial cells in the mucosa and the detrusor itself, as well as other muscular elements in the mucosa may substantially influence them. They are identified in several models explaining lower urinary tract dysfunction.

A consensus meeting at the International Consultation on Incontinence Research Society (ICI-RS) 2017 congress considered the origins and relevance of spontaneous bladder contractions by debating which cell type(s) modulate bladder spontaneous activity, whether the methodologies are sufficiently robust, and implications for healthy and abnormal lower urinary tract function.

The identified research priorities reflect a wide range of unknown aspects. Cellular contributions to spontaneous contractions in detrusor smooth muscle are still uncertain. Accordingly, insight into the cellular physiology of the bladder wall, particularly smooth muscle cells, interstitial cells, and urothelium, remains important. Upstream influences, such as innervation, endocrine, and paracrine factors, are particularly important. The cellular interactions represent the key understanding to derive the integrative physiology of organ function, notably the nature of signalling between mucosa and detrusor layers. Indeed, it is still not clear to what extent spontaneous contractions generated in isolated preparations mirror their normal and pathological counterparts in the intact bladder. Improved models of how spontaneous contractions influence pressure generation and sensory nerve function are also needed.

Deriving approaches to robust evaluation of spontaneous contractions and their influences for experimental and clinical use could yield considerable progress in functional urology.

Neurourology and urodynamics. 2018 Jan 23 [Epub ahead of print]

Marcus J Drake, Christopher H Fry, Hikaru Hashitani, Ruth Kirschner-Hermanns, Mohammad S Rahnama'i, John E Speich, Hikaru Tomoe, Anthony J Kanai, Karen D McCloskey

Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom., School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom., Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan., Neuro-Urology/Urology, University Clinic, Rheinische Friedrich Wilhelms University Bonn and Neurological Rehabilitation Center Godeshöhe, Bonn, Germany., Maastricht University, Maastricht, The Netherlands., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia., Department of Urology and Pelvic Reconstructive Surgery, Tokyo Women's Medical University Medical Center East, Tokyo, Japan., Department of Medicine, Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania., Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, United Kingdom.