Adjustable passive stiffness in mouse bladder: regulated by Rho kinase and elevated following partial bladder outlet obstruction

Speich, John E.; Southern, Jordan B.; Henderson, Sheree; Wilson, Cameron W.; Klausner, Adam P.; Ratz, Paul H.

doi:10.1152/ajprenal.00177.2011

Cited by 12 publications

(32 citation statements)

References 51 publications

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“…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).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, bladder wall elasticity is strain-history-dependent and activation-history-dependent. 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).…”

Section: Introductionmentioning

confidence: 99%

“…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). Together, these preclinical and clinical data provide evidence that detrusor overactivity, and potentially overactive bladder in humans, may be associated with dynamic elasticity.…”

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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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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“…39 In rabbit and mouse DSM, the L-T p curve can be shifted along the length axis as a function of activation and strain history, and we have termed this characteristic ''adjustable preload stiffness'' (APS). 2,[41][42][43] During the filling phase, the bladder can display SRC with a weaker contractile amplitude than the contraction responsible for voiding. 9 SRC is also referred to as autonomous contractile activity 17 and has been identified in mice, 8 rats, 25 guinea pigs, 10 rabbits, 26 cats, 16 and humans.…”

Section: Introductionmentioning

confidence: 99%

Carbachol-Induced Volume Adaptation in Mouse Bladder and Length Adaptation via Rhythmic Contraction in Rabbit Detrusor

et al. 2012

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The length-tension (L-T) relationships in rabbit detrusor smooth muscle (DSM) are similar to those in vascular and airway smooth muscles and exhibit short-term length adaptation characterized by L-T curves that shift along the length axis as a function of activation and strain history. In contrast to skeletal muscle, the length-active tension (L-T(a)) curve for rabbit DSM strips does not have a unique peak tension value with a single ascending and descending limb. Instead, DSM can exhibit multiple ascending and descending limbs, and repeated KCl-induced contractions at a particular muscle length on an ascending or descending limb display increasingly greater tension. In the present study, mouse bladder strips with and without urothelium exhibited KCl-induced and carbachol-induced length adaptation, and the pressure-volume relationship in mouse whole bladder displayed short-term volume adaptation. Finally, prostaglandin-E(2)-induced low-level rhythmic contraction produced length adaptation in rabbit DSM strips. A likely role of length adaptation during bladder filling is to prepare DSM cells to contract efficiently over a broad range of volumes. Mammalian bladders exhibit spontaneous rhythmic contraction (SRC) during the filling phase and SRC is elevated in humans with overactive bladder (OAB). The present data identify a potential physiological role for SRC in bladder adaptation and motivate the investigation of a potential link between short-term volume adaptation and OAB with impaired contractility.

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“…This might suggest that cross-bridges do not participate in adjustable preload stress in this tissue. However, rhoA kinase can cause Ca 2+ -independent increases in smooth muscle MLC-p, and small molecule inhibitors of both cross-bridge and rhoA kinase activities prevent recovery during subsequent stimulation at a short muscle length, suggesting that adjustable preload stress likely involves crossbridges or structures associated with them (382,446,449). Whether cross-bridges are necessary to "reel-in" and reset strain-softened tissues that lack the compressional forces needed to "push" internal dashpot-like structures back to their prestrained orientations remains to be determined.…”

Section: Figure 26mentioning

confidence: 99%

Mechanics of Vascular Smooth Muscle

Ratz

2015

Comprehensive Physiology

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Vascular smooth muscle (VSM; see Table 1 for a list of abbreviations) is a heterogeneous biomaterial comprised of cells and extracellular matrix. By surrounding tubes of endothelial cells, VSM forms a regulated network, the vasculature, through which oxygenated blood supplies specialized organs, permitting the development of large multicellular organisms. VSM cells, the engine of the vasculature, house a set of regulated nanomotors that permit rapid stress-development, sustained stress-maintenance and vessel constriction. Viscoelastic materials within, surrounding and attached to VSM cells, comprised largely of polymeric proteins with complex mechanical characteristics, assist the engine with countering loads imposed by the heart pump, and with control of relengthening after constriction. The complexity of this smart material can be reduced by classical mechanical studies combined with circuit modeling using spring and dashpot elements. Evaluation of the mechanical characteristics of VSM requires a more complete understanding of the mechanics and regulation of its biochemical parts, and ultimately, an understanding of how these parts work together to form the machinery of the vascular tree. Current molecular studies provide detailed mechanical data about single polymeric molecules, revealing viscoelasticity and plasticity at the protein domain level, the unique biological slip-catch bond, and a regulated two-step actomyosin power stroke. At the tissue level, new insight into acutely dynamic stress-strain behavior reveals smooth muscle to exhibit adaptive plasticity. At its core, physiology aims to describe the complex interactions of molecular systems, clarifying structure-function relationships and regulation of biological machines. The intent of this review is to provide a comprehensive presentation of one biomachine, VSM.

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Adjustable passive stiffness in mouse bladder: regulated by Rho kinase and elevated following partial bladder outlet obstruction

Cited by 12 publications

References 51 publications

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

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

Carbachol-Induced Volume Adaptation in Mouse Bladder and Length Adaptation via Rhythmic Contraction in Rabbit Detrusor

Mechanics of Vascular Smooth Muscle

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