Acute length adaptation and adjustable preload in the human detrusor

Colhoun, Andrew; Speich, John E.; Dolat, MaryEllen T.; Habibi, Joseph; Guruli, Georgi; Ratz, Paul H.; Barbee, R. Wayne; Klausner, Adam P.

doi:10.1002/nau.22820

Cited by 11 publications

(27 citation statements)

References 25 publications

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“…Adjustable preload tension has been identified in human bladder strips (Colhoun, Speich et al 2015), and the present modeling results indicate that adjustable preload tension could have a significant effect on bladder wall stress during filling. Furthermore, a potential defect in the acute regulation of bladder elasticity could contribute to a significant change in wall stress for a given bladder volume, and therefore alter the load on the mechanosensors responsible for bladder sensation at that volume and contribute to urgency.…”

Section: Discussionmentioning

confidence: 53%

“…As described in the introduction, detrusor smooth muscle strips exhibit adjustable preload tension (Speich, Borgsmiller et al 2005, Colhoun, Speich et al 2015). The stress at the first muscle length of the experimental loading curve in Fig 1A (6.3 mm) was not zero because tissues had been previously strain softened and then contracted at 6 mm to reestablish any adjustable preload tension lost to the strain-induced stress softening (Speich, Dosier et al 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have demonstrated that repeated stretches of “passive” rabbit, mouse or human bladder strips (Speich, Borgsmiller et al 2005, Speich, Quintero et al 2006, Ratz and Speich 2010, Rubod, Brieu et al 2012, Colhoun, Speich et al 2015) can cause strain-induced stress softening and reveal the Mullins effect (Mullins, Tobin et al 1966). Likewise, repeated filling of isolated mouse bladders (Speich, Southern et al 2012) can soften the bladder, just as repeated stretches of a latex balloon make it easier to inflate.…”

Section: Introductionmentioning

confidence: 99%

“…Likewise, repeated filling of isolated mouse bladders (Speich, Southern et al 2012) can soften the bladder, just as repeated stretches of a latex balloon make it easier to inflate. Moreover, strain-induced stress softening can be reversed by active contraction at short muscle lengths (Speich, Borgsmiller et al 2005, Almasri, Ratz et al 2010, Colhoun, Speich et al 2015). Thus, bladder wall elasticity is strain-history-dependent and activation-history-dependent.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, adjustable preload tension in mouse bladder is elevated following partial bladder outlet obstruction (Speich, Southern et al 2012). Most importantly, strain-induced stress softening has been identified in human detrusor (Colhoun, Speich et al 2015) and quantified as dynamic elasticity due to strain-induced stress softening during a pilot human comparative-fill urodynamics study (Colhoun, Klausner et al 2016). Furthermore, the change in elasticity associated with repeated passive filling has been shown to be greater in a partial bladder outlet obstructed mouse model of detrusor overactivity (Speich, Southern et al 2012).…”

Section: Introductionmentioning

confidence: 99%

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Modeling the influence of acute changes in bladder elasticity on pressure and wall tension during filling

Habteyes

Komari

Nagle

et al. 2017

Journal of the Mechanical Behavior of Biomedical Materials

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Tension-sensitive nerves in the bladder wall are responsible for providing bladder sensation. Bladder wall tension, and therefore nerve output, is a function of bladder pressure, volume, geometry and material properties. The elastic modulus of the bladder is acutely adjustable, and this material property is responsible for adjustable preload tension exhibited in human and rabbit detrusor muscle strips and dynamic elasticity revealed during comparative-fill urodynamics in humans. A finite deformation model of the bladder was previously used to predict filling pressure and wall tension using uniaxial tension test data and the results showed that wall tension can increase significantly during filling with relatively little pressure change. In the present study, published uniaxial rabbit detrusor data were used to quantify regulated changes in the elastic modulus, and the finite deformation model was expanded to illustrate the potential effects of elasticity changes on pressure and wall tension during filling. The model demonstrates a shift between relatively flat pressure-volume filling curves, which is consistent with a recent human urodynamics study, and also predicts that dynamic elasticity would produce significant changes in wall tension during filling. The model results support the conclusion that acute regulation of bladder elasticity could contribute to significant changes in wall tension for a given volume that could lead to urgency, and that a single urodynamic fill may be insufficient to characterize bladder biomechanics. The model illustrates the potential value of quantifying wall tension in addition to pressure during urodynamics.

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Section: Discussionmentioning

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modeling the influence of acute changes in bladder elasticity on pressure and wall tension during filling

Habteyes

Komari

Nagle

et al. 2017

Journal of the Mechanical Behavior of Biomedical Materials

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A pilot study to measure dynamic elasticity of the bladder during urodynamics

Colhoun

Klausner

Nagle

et al. 2016

Neurourology and Urodynamics

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AIMS Previous studies using isolated strips of human detrusor muscle identified adjustable preload tension, a novel mechanism that acutely regulates detrusor wall tension. The purpose of this investigation was to develop a method to identify a correlate measure of adjustable preload tension during urodynamics. METHODS Patients reporting urgency most or all of the time based on ICIq-OAB survey scores were prospectively enrolled in an extended repeat fill-and-empty urodynamics study designed to identify a correlate of adjustable preload tension which we now call “dynamic elasticity.” Cystometric capacity was determined during initial fill. Repeat fills to defined percentages of capacity with passive emptying (via syringe aspiration) were performed to strain soften the bladder. A complete fill with active voiding was included to determine whether human bladder exhibits reversible strain softening. RESULTS Five patients completed the extended urodynamics study. Intravesical pressure (pves) decreased with subsequent fills and was significantly lower during Fill 3 compared to Fill 1 (P =0.008), demonstrating strain softening. Active voiding after Fill 3 caused strain softening reversal, with pves in Fill 4 returning to the baseline measured during Fill 1 (P = 0.29). Dynamic elasticity, the urodynamic correlate of adjustable preload tension, was calculated as the amount of strain softening (or its reversal) per % capacity (Δaverage pves between fills/Δ%capacity). Dynamic elasticity was lost via repeat passive filling and emptying (strain softening) and regained after active voiding regulated the process (strain softening reversal). CONCLUSIONS Improved understanding of dynamic elasticity in the human bladder could lead to both improved sub-typing and novel treatments of overactive bladder.

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