Do we understand any more about bladder interstitial cells?-ICI-RS 2013

Abstract

Aims To present a brief review on discussions from “Do we understand any more about lower urinary tract interstitial cells?” session at the 2013 International Consultation on Incontinence-Research Society (ICI-RS) meeting in Bristol, UK. Methods Discussion focused on bladder interstitial cell (IC) subtypes, their localization and characterization, and communication between themselves, the urothelium, and detrusor smooth muscle. The role of ICs in bladder pathologies and new methods for studying ICs were also addressed. Results ICs have been studied extensively in the lower urinary tract and have been characterized based on comparisons with ICs of Cajal in the gastro-intestinal tract. In fetal bladders it is believed that ICs drive intrinsic contractions to expel urine through the urachus. These contractions diminish postpartum as bladder innervation develops. Voiding in human neonates occurs when filling triggers a spinal cord reflex that contracts the detrusor; in rodents, maternal stimulation of the perineum triggers voiding. Following spinal cord injury, intrinsic contractions, and spinal micturition reflexes develop, similar to those seen during neonatal development. These enhanced contractions may stimulate nociceptive and mechanosensitive afferents contributing to neurogenic detrusor overactivity and incontinence. The IC-mediated activity is believed to be initiated in the lamina propria by responding to urothelial factors. These IC may act syncytially through gap junction coupling and modulate detrusor activity through unknown mechanisms. Conclusion There has been a great deal of information discovered regarding bladder ICs, however, many of their (patho)physiological functions and mechanisms are still unclear and necessitates further research.

3D‐electron microscopic characterization of interstitial cells in the human bladder upper lamina propria

“…The overall morphology and spatial orientation of mIC speak in favor of the notion that those cells are important players in the afferent signaling cascade . The cells are stacked in parallel to the urothelium for maximum membrane presentation.…”

“…The overall morphology and spatial orientation of mIC speak in favor of the notion that those cells are important players in the afferent signaling cascade. 1,2,18,19 The cells are stacked in parallel to the urothelium for maximum membrane presentation. Thus, they would be optimal positioned to sense humoral factors released by the urothelium, for example, ATP during bladder filling.…”

“…Urinary bladder cellular composition is of utmost importance for the understanding of normal and pathological bladder function. There is a growing awareness of the heterogeneity of cells comprising the bladder wall regarding structure, immunological characteristics and receptor expression . While urothelial contribution to proper bladder function is well defined by establishing urine‐tissue barrier and serving as sensor for bladder filling, the function of the interstitial cells, representing the clear majority of cells within the lamina propria, is less well understood.…”

“…There is a growing awareness of the heterogeneity of cells comprising the bladder wall regarding structure, immunological characteristics and receptor expression. 1 While urothelial contribution to proper bladder function is well defined by establishing urine-tissue barrier and serving as sensor for bladder filling, the function of the interstitial cells, representing the clear majority of cells within the lamina propria, is less well understood. They have been implicated in afferent signal processing because of their close association with sensory neurons, their receptor expression and their physiological properties.…”

Distribution of interstitial cells of Cajal in the bladders of fetal rats with retinoic acid induced myelomeningocele

“…[5,[9][10][11][12][13] Although the gastrointestinal and bladder ICCs seem to share the same morphological and receptor expressions, they function differently. [14] Different neurological and functional conditions of the bladder have been associated with changes in the number of ICCs. [9] It has been shown that the number of ICCs decrease in the rat bladder after traumatic spinal cord injury.…”