Unravelling the underactive bladder: a role for TRPV4?

Defining and advancing education and conservative therapies of underactive bladder

In contrast to other forms of voiding dysfunction, underactive bladder (UAB) has traditionally received little research or educational attention. This is changing as our understanding of the underlying mechanisms of detrusor dysfunction and other forms of underactive bladder improves. In addition, the impact of UAB on patient symptoms, general and health-related quality of life, and caregiver burden are becoming more recognized. However, there remains a paucity of data on the subject, and an extensive need for additional research and education on the topic. This paper explores the current state of knowledge about UAB with an emphasis on education regarding the condition and conservative methods of assessment and treatment. Recommendations for future work in this area are considered.

Detrusor Underactivity: The Current Concept of the Pathophysiology

Based on evidence from available literature, we review the pathophysiology of detrusor underactivity (DU). DU is likely to be multifactorial. Aging reduces detrusor activity, but other concomitant causes may aggravate this condition, resulting in decrease of detrusor contractility. Impaired detrusor contractility has been regarded as a major etiologic factor of DU. However, a more complex pathology has been proposed. As contributing factors to DU, we discuss disturbances of the sensory afferent side of the micturition reflex, the central nervous system (CNS) and the efferent side of the reflex, including nerves and the detrusor muscle. Particularly, dysfunction of afferent nerves in the bladder and urethra may play a crucial role in the pathogenesis of DU. In addition, recent studies suggest that chronic bladder ischemia and resultant oxidative stress cause detrusor overactivity progressing to DU and inability to empty the bladder.

Transient receptor potential channels as drug targets: from the science of basic research to the art of medicine

The large Trp gene family encodes transient receptor potential (TRP) proteins that form novel cation-selective ion channels. In mammals, 28 Trp channel genes have been identified. TRP proteins exhibit diverse permeation and gating properties and are involved in a plethora of physiologic functions with a strong impact on cellular sensing and signaling pathways. Indeed, mutations in human genes encoding TRP channels, the so-called "TRP channelopathies," are responsible for a number of hereditary diseases that affect the musculoskeletal, cardiovascular, genitourinary, and nervous systems. This review gives an overview of the functional properties of mammalian TRP channels, describes their roles in acquired and hereditary diseases, and discusses their potential as drug targets for therapeutic intervention.

Detrusor underactivity: Pathophysiological considerations, models and proposals for future research. ICI-RS 2013

AIMS

Detrusor underactivity, resulting in either prolonged or inefficient voiding, is a common clinical problem for which treatment options are currently limited. The aim of this report is to summarize current understanding of the clinical observation and its underlying pathophysiological entities.

METHODS

This report results from presentations and subsequent discussion at the International Consultation on Incontinence Research Society (ICI-RS) in Bristol, 2013.

RESULTS AND CONCLUSIONS

The recommendations made by the ICI-RS panel include: Development of study tools based on a system's pathophysiological approach, correlation of in vitro and in vivo data in experimental animals and humans, and development of more comprehensive translational animal models. In addition, there is a need for longitudinal patient data to define risk groups and for the development of screening tools. In the near-future these recommendations should lead to a better understanding of detrusor underactivity and its pathophysiological background. Neurourol. Urodynam. 33:591-596, 2014. © 2014 Wiley Periodicals, Inc.