Acute length adaptation and adjustable preload in the human detrusor

作者：Colhoun Andrew F; Speich John E; Dolat MaryEllen T; Habibi Joseph R; Guruli Georgi; Ratz Paul H; Barbee Robert W; Klausner Adam P^*

来源：Neurourology and Urodynamics, 2016, 35(7): 792-797.

DOI：10.1002/nau.22820

• compliance
• overactive
• rho-kinase
• urinary bladder

AimsThe biomechanical properties of length adaptation and adjustable preload have been previously identified in detrusor smooth muscle in animal models. This in vitro study aims to show that human detrusor smooth muscle exhibits length adaptation and adjustable preload tension which could play an important role in both overactive bladder and detrusor underactivity.
MethodsIn order to demonstrate length adaptation, human detrusor smooth muscle strips are stretched and contracted beyond an optimum length and then contracted three times at the previous optimum length to determine if maximum active tension could be re-established. To demonstrate adjustable preload (T-ap), human detrusor smooth muscle strips are subjected to a pre-defined loading-unloading (strain softening) sequence to reduce preload. Then, tissues are contracted and the sequence is repeated to determine if this active process restored preload.
ResultsNine patients (average age, 62) provide tissue: 89% are men with urothelial carcinoma and a minority (22%) also have neurogenic bladder dysfunction. In the length adaptation protocol, contractions show progressive increases in active tension (P<0.05). In the T-ap protocol, a significant amount of preload is lost to strain softening (P<0.05) and is restored after active contraction (P=0.50). Exposure to the rho-kinase inhibitor, H-1152, prevents the restoration of preload (P<0.05).
ConclusionsThis study demonstrates that human detrusor smooth muscle displays both length adaptation and T-ap. Furthermore, T-ap may be regulatable through a rho-kinase pathway. These biomechanical processes may be important in the pathophysiology of both overactive bladder and detrusor underactivity. Neurourol. Urodynam. 35:792-797, 2016.

• 出版日期2016-9