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Ergun R, Sekerci CA, Tanidir Y, Ozturk Nİ, Tarcan T, Yucel S. The results of three times repeated filling cystometry and pressure flow studies in children with non-neurogenic lower urinary tract dysfunction. Neurourol Urodyn 2022; 41:1157-1164. [PMID: 35419875 DOI: 10.1002/nau.24934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 03/10/2022] [Accepted: 03/30/2022] [Indexed: 12/24/2022]
Abstract
AIM We previously reported that some urodynamic parameters change with repetitive filling in children with neurogenic lower urinary tract dysfunction (LUTD). In this study, we aimed to search if three-times repeated filling cystometries (FC) and pressure-flow studies (PFS) would change the urodynamics parameters in children with non-neurogenic LUTD. MATERIALS AND METHODS All children with three repeated FC and PFS between June 2017 and December 2018 were included in the study. Urodynamic reports and charts were evaluated retrospectively. The first sensation of bladder filling (FSBF), maximum cystometric capacity (MCC), detrusor pressure at the FSBF (Pdet.first.sens ), maximum detrusor pressure during filling (Pdet.fill.max ), presence of detrusor over activity, compliance, maximum urine flow (Qmax), detrusor pressure at the maximum urine flow (PdetQmax), residual urine and presence of detrusor sphincter dyssynergy (DSD) were compared among three-times repeated urodynamic studies. RESULTS Forty children were included in the study. 27 (67.5%) were girls and 13 (32.5%) were boys. Median age was 9 (3.4-17) years. Indications were LUTD with low grade vesicoureteral reflux in 19 (47.5%), LUTD refractory to conservative management in 13 (32.5%), urinary tract infection with LUTD in 6 (15%) and secondary enuresis in 2 (5%). Pdet.first.sens , presence of DO, MCC, Qmax, PdetQmax, residual urine, flow pattern, and presence of DSD were comparable in all three repeated tests. The third FC may show decreased filling detrusor pressures and increased compliance with no change on capacity. CONCLUSION In children with non-neurogenic LUTD, three-times repeated FC and PFS present comparable results except FSBF, Pdet.fill.max, and compliance at the third test.
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Affiliation(s)
- Raziye Ergun
- Department of Pediatric Urology, Derince Training and Research Hospital, Kocaeli, Turkey
| | - Cagri Akin Sekerci
- Department of Urology, Division of Pediatric Urology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Yiloren Tanidir
- Department of Urology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Naime İpek Ozturk
- Department of Pediatric Surgery, Derince Training and Research Hospital, Kocaeli, Turkey
| | - Tufan Tarcan
- Department of Urology, Division of Pediatric Urology, School of Medicine, Marmara University, Istanbul, Turkey.,Department of Urology, School of Medicine, Koç University, Istanbul, Turkey
| | - Selcuk Yucel
- Department of Urology, Division of Pediatric Urology, School of Medicine, Marmara University, Istanbul, Turkey
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Regulation of bladder dynamic elasticity: a novel method to increase bladder capacity and reduce pressure using pulsatile external compressive exercises in a porcine model. Int Urol Nephrol 2021; 53:1819-1825. [PMID: 34212270 DOI: 10.1007/s11255-021-02863-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/11/2021] [Indexed: 12/27/2022]
Abstract
PURPOSE Dynamic elasticity is a biomechanical property of the bladder in which muscle compliance can be acutely adjusted through passive stretches and reversed with active contractions. The aim of this study was to determine if manipulating dynamic elasticity using external compression could be used as a novel method to acutely increase bladder capacity and reduce bladder pressure in a porcine model. METHODS Ex vivo experiment: bladders underwent continuous or pulsatile compression after establishing a reference pressure at bladder capacity. Bladders were then filled back to the reference pressure to determine if capacity could be acutely increased. In-vivo experiments: bladders underwent five cycles of pulsatile external compression with ultrasound confirmation. Pre and post-compression pressures were measured, and pressure was measured again 10 min post-compression. RESULTS Ex vivo experiment: pulsatile compression demonstrated increased bladder capacity by 16% (p = 0.01). Continuous compression demonstrated increased capacity by 9% (p < 0.03). Comparison of pulsatile to continuous compression showed that the pulsatile method was superior (p = 0.03). In-vivo experiments: pulsatile external compression reduced bladder pressure by 19% (p < 0.00001) with a return to baseline 10 min post-compression. CONCLUSIONS These results suggest that regulation of bladder dynamic elasticity achieved with external compression can acutely decrease bladder pressure and increase bladder capacity. Pulsatile compression was found to be more effective as compared to continuous compression. These results highlight the clinical potential for use of non-invasive pulsatile compression as a therapeutic technique to increase bladder capacity, decrease bladder pressure, and reduce the symptoms of urinary urgency.
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Tracey AT, Anele UA, Vince RA, Speich JE, Klausner AP, Ratz PH. Bladder attack: transient bladder ischemia leads to a reversible decrease in detrusor compliance. Transl Androl Urol 2019; 8:703-711. [PMID: 32038967 DOI: 10.21037/tau.2019.11.12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Background The deleterious effects of chronic ischemia on bladder function have been extensively studied; however, evaluation and characterization of the effects of acute ischemia and hypoxia are lacking. The present study examined pig and human detrusor smooth muscle (DSM) strips, in combination with an isolated perfused working pig bladder model to evaluate the relationship between transient ischemia and bladder function. Methods Organ bath and myographic studies were performed using pig and human DSM strips exposed to starvation/hypoxia conditions. Analogous conditions were then recreated in the ex vivo bladder preparation. Filled bladders were then treated with intravascular carbachol to induce contraction and subsequent void. An intravesical transducer continuously monitored changes in bladder pressure, while a tissue pO2 monitor analyzed changes in oxygenation. Results After 120 min in starved/hypoxic conditions, both pig and human DSM strips demonstrated significantly increased resting tone, with a greater than two-fold increase in force over control. This was effectively blocked with atropine. DSM strips also demonstrated significantly weaker contractions; however, contractile force was nearly recovered following 15-min exposure to replete/oxygenated buffer. In the ex vivo bladder preparation, filling under ischemic conditions yielded a 225% increase in end-fill vesical pressures (Pves) compared to controls. End-fill Pves returned to baseline with reperfusion during a subsequent filling cycle. Conclusions Transient ischemia/hypoxia leads to an acute increase in tone in both DSM strips and ex vivo pig bladder. Remarkably, the effect is reversible with re-perfusion and may be blocked with anticholinergics, suggesting a relationship between acute ischemia and increased local acetylcholine release.
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Affiliation(s)
- Andrew T Tracey
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Uzoma A Anele
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Randy A Vince
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Adam P Klausner
- Division of Urology, Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Paul H Ratz
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
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Swavely NR, Speich JE, Stothers L, Klausner AP. New Diagnostics for Male Lower Urinary Tract Symptoms. CURRENT BLADDER DYSFUNCTION REPORTS 2019; 14:90-97. [PMID: 31938079 PMCID: PMC6959483 DOI: 10.1007/s11884-019-00511-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW Lower urinary tract symptoms (LUTS) is a common constellation of symptoms that affect the aging male population with an astonishing prevalence. New technology and new uses of established technology are being used to help further evaluate LUTS in the male population and help guide treatment options. This review focuses on the developments and future directions in diagnostic modalities for evaluation of male LUTS, focusing on evaluation of both the filling and voiding phases of micturition. RECENT FINDINGS New techniques in evaluating the voiding phase include penile cuff test, external pressure sensing condom catheter, ultrasound measurement of detrusor wall thickness, ultrasound measurement of intravesical prostatic protrusion, doppler ultrasound and NIRS technology. Evaluation of the filling phase is still undergoing much development and requires additional validation studies. The techniques undergoing evaluation include sensation meters during UDS, assessing bladder micromotion and wall rhythm, assessing detrusor wall biomechanics, ultrasound measurement of detrusor wall thickness, pelvic doppler ultrasound, as well as functional brain imaging including fNIRS and fMRI. SUMMARY The development of novel, non-invasive, diagnostic tools have the potential for better evaluation of LUTS with earlier and enhanced treatments. This will likely improve the quality of life for men with LUTS.
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Affiliation(s)
- Natalie R Swavely
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, VA
| | - John E Speich
- Department of Mechanical & Nuclear Engineering, Virginia Commonwealth University College of Engineering, Richmond, VA
| | - Lynn Stothers
- Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Adam P Klausner
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, VA
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Balthazar A, Cullingsworth ZE, Nandanan N, Anele U, Swavely NR, Speich JE, Klausner AP. An external compress-release protocol induces dynamic elasticity in the porcine bladder: A novel technique for the treatment of overactive bladder? Neurourol Urodyn 2019; 38:1222-1228. [PMID: 30947371 DOI: 10.1002/nau.23992] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 03/14/2019] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Dynamic elasticity is an acutely regulated bladder material property through which filling and passive emptying produce strain softening, and active voiding restores baseline pressure. The aim of this study was to test the hypothesis that strain softening produced by filling-passive emptying is equivalent to that produced by compression-release in a porcine bladder model. METHODS/MATERIALS Latex balloons and ex vivo perfused pig bladders were used for a series of alternating fill-passive emptying ("Fill") and external compress-release ("Press") protocols. For the Fill protocol balloons/bladders were (1) filled to defined volumes (prestrain softening), (2) filled to capacity to strain soften (reference), and (3) passively emptied to the original volume (poststrain softening). For the Press protocol, balloons/bladders were (1) filled to defined volumes (prestrain softening), (2) externally compressed to reference pressure and then released for five cycles (poststrain softening). After each protocol, bladders were voided with high-KCl buffer to induce "active" voiding. RESULTS In both balloons and porcine bladder, both the Fill and Press protocols produced significant strain softening (P < 0.05) and poststrain softening pressures were not different for Fill and Press protocols (P > 0.05), indicating a similar degree of strain softening with both methods. CONCLUSIONS Repeated external compression can induce bladder strain softening similar to filling and passive emptying. This technique may represent a means to acutely regulate bladder compliance and potentially be used as a mechanical treatment for urinary urgency.
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Affiliation(s)
- Andrea Balthazar
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Zachary E Cullingsworth
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University College of Engineering, Richmond, Virginia
| | - Naveen Nandanan
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Uzoma Anele
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Natalie R Swavely
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University College of Engineering, Richmond, Virginia
| | - Adam P Klausner
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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Drake MJ, Fry CH, Hashitani H, Kirschner-Hermanns R, Rahnama'i MS, Speich JE, Tomoe H, Kanai AJ, McCloskey KD. What are the origins and relevance of spontaneous bladder contractions? ICI-RS 2017. Neurourol Urodyn 2018; 37:S13-S19. [PMID: 29360173 DOI: 10.1002/nau.23485] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/14/2017] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Storage phase bladder activity is a counter-intuitive observation of spontaneous contractions. They are potentially an intrinsic feature of the smooth muscle, but interstitial cells in the mucosa and the detrusor itself, as well as other muscular elements in the mucosa may substantially influence them. They are identified in several models explaining lower urinary tract dysfunction. METHODS A consensus meeting at the International Consultation on Incontinence Research Society (ICI-RS) 2017 congress considered the origins and relevance of spontaneous bladder contractions by debating which cell type(s) modulate bladder spontaneous activity, whether the methodologies are sufficiently robust, and implications for healthy and abnormal lower urinary tract function. RESULTS The identified research priorities reflect a wide range of unknown aspects. Cellular contributions to spontaneous contractions in detrusor smooth muscle are still uncertain. Accordingly, insight into the cellular physiology of the bladder wall, particularly smooth muscle cells, interstitial cells, and urothelium, remains important. Upstream influences, such as innervation, endocrine, and paracrine factors, are particularly important. The cellular interactions represent the key understanding to derive the integrative physiology of organ function, notably the nature of signalling between mucosa and detrusor layers. Indeed, it is still not clear to what extent spontaneous contractions generated in isolated preparations mirror their normal and pathological counterparts in the intact bladder. Improved models of how spontaneous contractions influence pressure generation and sensory nerve function are also needed. CONCLUSIONS Deriving approaches to robust evaluation of spontaneous contractions and their influences for experimental and clinical use could yield considerable progress in functional urology.
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Affiliation(s)
- Marcus J Drake
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.,Bristol Urological Institute, Southmead Hospital, Bristol, United Kingdom
| | - Christopher H Fry
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Ruth Kirschner-Hermanns
- Neuro-Urology/Urology, University Clinic, Rheinische Friedrich Wilhelms University Bonn and Neurological Rehabilitation Center Godeshöhe, Bonn, Germany
| | | | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia
| | - Hikaru Tomoe
- Department of Urology and Pelvic Reconstructive Surgery, Tokyo Women's Medical University Medical Center East, Tokyo, Japan
| | - Anthony J Kanai
- Department of Medicine, Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Karen D McCloskey
- Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, United Kingdom
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Habteyes FG, Komari SO, Nagle AS, Klausner AP, Heise RL, Ratz PH, Speich JE. Modeling the influence of acute changes in bladder elasticity on pressure and wall tension during filling. J Mech Behav Biomed Mater 2017; 71:192-200. [PMID: 28343086 DOI: 10.1016/j.jmbbm.2017.02.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 02/07/2017] [Accepted: 02/17/2017] [Indexed: 01/22/2023]
Abstract
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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Affiliation(s)
- Firdaweke G Habteyes
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - S Omid Komari
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Anna S Nagle
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Adam P Klausner
- Department of Surgery, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - Rebecca L Heise
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Paul H Ratz
- Departments of Biochemistry & Molecular Biology and Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, United States
| | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States.
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Low amplitude rhythmic contraction frequency in human detrusor strips correlates with phasic intravesical pressure waves. World J Urol 2016; 35:1255-1260. [PMID: 28025660 DOI: 10.1007/s00345-016-1994-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 12/16/2016] [Indexed: 10/24/2022] Open
Abstract
PURPOSE Low amplitude rhythmic contractions (LARC) occur in detrusor smooth muscle and may play a role in storage disorders such as overactive bladder and detrusor overactivity. The purpose of this study was to determine whether LARC frequencies identified in vitro from strips of human urinary bladder tissue correlate with in vivo LARC frequencies, visualized as phasic intravesical pressure (p ves) waves during urodynamics (UD). METHODS After IRB approval, fresh strips of human urinary bladder were obtained from patients. LARC was recorded with tissue strips at low tension (<2 g) and analyzed by fast Fourier transform (FFT) to identify LARC signal frequencies. Blinded UD tracings were retrospectively reviewed for signs of LARC on the p ves tracing during filling and were analyzed via FFT. RESULTS Distinct LARC frequencies were identified in 100% of tissue strips (n = 9) obtained with a mean frequency of 1.97 ± 0.47 cycles/min (33 ± 8 mHz). Out of 100 consecutive UD studies reviewed, 35 visually displayed phasic p ves waves. In 12/35 (34%), real p ves signals were present that were independent of abdominal activity. Average UD LARC frequency was 2.34 ± 0.36 cycles/min (39 ± 6 mHz) which was similar to tissue LARC frequencies (p = 0.50). A majority (83%) of the UD cohort with LARC signals also demonstrated detrusor overactivity. CONCLUSIONS During UD, a subset of patients displayed phasic p ves waves with a distinct rhythmic frequency similar to the in vitro LARC frequency quantified in human urinary bladder tissue strips. Further refinements of this technique may help identify subsets of individuals with LARC-mediated storage disorders.
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Colhoun AF, Klausner AP, Nagle AS, Carroll AW, Barbee RW, Ratz PH, Speich JE. A pilot study to measure dynamic elasticity of the bladder during urodynamics. Neurourol Urodyn 2016; 36:1086-1090. [PMID: 27241067 DOI: 10.1002/nau.23043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/10/2016] [Indexed: 11/07/2022]
Abstract
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. Neurourol. Urodynam. 36:1086-1090, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Andrew F Colhoun
- Division of Urology/Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Adam P Klausner
- Division of Urology/Department of Surgery, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Anna S Nagle
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University School of Engineering, Richmond, Virginia
| | - Ashley W Carroll
- Department of Obstetrics and Gynecology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Robert W Barbee
- Departments of Emergency Medicine and Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Paul H Ratz
- Departments of Biochemistry and Molecular Biology and Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University School of Engineering, Richmond, Virginia
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Colhoun AF, Speich JE, Dolat MT, Habibi JR, Guruli G, Ratz PH, Barbee RW, Klausner AP. Acute length adaptation and adjustable preload in the human detrusor. Neurourol Urodyn 2015; 35:792-7. [DOI: 10.1002/nau.22820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 06/01/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Andrew F. Colhoun
- Department of Surgery/Division of Urology; Virginia Commonwealth University School of Medicine; Richmond Virginia
| | - John E. Speich
- Department of Mechanical and Nuclear Engineering; Virginia Commonwealth University School of Engineering; Richmond Virginia
| | - MaryEllen T. Dolat
- Department of Surgery/Division of Urology; Virginia Commonwealth University School of Medicine; Richmond Virginia
| | - Joseph R. Habibi
- Department of Surgery/Division of Urology; Virginia Commonwealth University School of Medicine; Richmond Virginia
| | - Georgi Guruli
- Department of Surgery/Division of Urology; Virginia Commonwealth University School of Medicine; Richmond Virginia
| | - Paul H. Ratz
- Departments of Biochemistry and Pediatrics; Virginia Commonwealth University School of Medicine; Richmond Virginia
| | - Robert W. Barbee
- Department of Emergency Medicine; Virginia Commonwealth University School of Medicine; Richmond Virginia
| | - Adam P. Klausner
- Department of Surgery/Division of Urology; Virginia Commonwealth University School of Medicine; Richmond Virginia
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Komari SO, Headley PC, Klausner AP, Ratz PH, Speich JE. Evidence for a common mechanism for spontaneous rhythmic contraction and myogenic contraction induced by quick stretch in detrusor smooth muscle. Physiol Rep 2013; 1:e00168. [PMID: 24400167 PMCID: PMC3871480 DOI: 10.1002/phy2.168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 10/28/2013] [Accepted: 10/29/2013] [Indexed: 11/23/2022] Open
Abstract
Detrusor smooth muscle exhibits myogenic contraction in response to a quick stretch (QS) as well as spontaneous rhythmic contraction (SRC); however, whether the same population of actomyosin crossbridges with a common regulatory mechanism is responsible for these two types of contraction has not been determined. Detrusor strips from New Zealand white rabbit bladders were allowed to develop SRC at a reference muscle length (Lref), or rhythmic contraction (RC) was induced with tetraethylammonium (TEA). Multiple 10-msec stretches of 15% Lref were then imposed at Lref randomly during the rhythm cycle, and the nadir-to-peak (NTP) tension amplitude of the resulting myogenic contraction was measured. The amplitude and period of the rhythm cycle were measured prior to each QS. NTP was larger when a QS was imposed during a portion the cycle when tension was smaller (n = 3 each SRC and TEA-induced RC). These data suggest that when the rhythmic mechanism was mostly inactive and tension was near a minimum, a larger portion of a shared population of crossbridges was available to produce a myogenic response to a QS. Rho kinase, cyclooxygenase-1, and cyclooxygenase-2 inhibitors (H-1152, SC-560, and NS-398) affected SRC amplitude and NTP amplitude following a QS to the same degree (n = 3 each drug), providing additional evidence to support the hypothesis that a common mechanism is responsible for SRC and myogenic contraction due to QS. If a common mechanism exists, then QS is a potential mechanical probe to study SRC regulation and its alteration in overactive bladder.
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Affiliation(s)
- S Omid Komari
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University Richmond, Virginia, 23284
| | - Patrick C Headley
- Department of Biomedical Engineering, Virginia Commonwealth University Richmond, Virginia, 23284
| | - Adam P Klausner
- Department of Surgery, Virginia Commonwealth University Richmond, Virginia, 23298
| | - Paul H Ratz
- Departments of Biochemistry & Molecular Biology and Pediatrics, Virginia Commonwealth University Richmond, Virginia, 23298
| | - John E Speich
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University Richmond, Virginia, 23284
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Klausner AP, King AB, Byrne MD, Habibi JR, Li K, Sabarwal V, Speich JE, Ratz PH. A new and automated method for objective analysis of detrusor rhythm during the filling phase. World J Urol 2013; 32:85-90. [PMID: 23633125 DOI: 10.1007/s00345-013-1084-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 04/18/2013] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION There is growing acceptance that the detrusor muscle is not silent during the filling phase of the micturition cycle but displays low-amplitude phasic contractions that have been associated with urinary urgency. Unfortunately, there is currently no standardized methodology to quantify detrusor rhythm during the filling phase. Therefore, the purpose of this study was to develop an automated computer algorithm to analyze rat detrusor rhythm in a quick, accurate, and reproducible manner. MATERIALS AND METHODS Strips of detrusor smooth muscle from rats (n = 17) were placed on force transducers and subjected to escalating doses of PGE2 to generate contractile rhythm tracings. An automated computer algorithm was developed to analyze contractile frequency, amplitude, and tone on the generated rhythm tracings. Results of the automated computerized analysis were compared to human (n = 3) interpretations. Human interpreters manually counted contractions and then recounted the same data two weeks later. Intra-observer, inter-observer, and human-to-computer comparisons were performed. RESULTS The computer algorithm quantified concentration-dependent changes in contractile frequency, amplitude, and tone after administration of PGE2 (10(-9)-10(-6)M). Concentration-response curves were similar for all contractile components with increases in frequency identified mainly at physiologic concentrations of PGE2 and increases in amplitude at supra-physiologic concentrations. The computer algorithm consistently over-counted the human interpreters, but with less variability. Differences in inter-observer consistency were statistically significant. CONCLUSIONS Our computerized algorithm accurately and consistently identified changes in detrusor muscle contractile frequency, amplitude, and tone with varying doses of PGE2. Frequency counts were consistently higher than those obtained by human interpreters but without variability or bias. Refinements of this method may allow for more standardized approach in the study of pharmacologic agents on filling phase rhythmic activity.
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Affiliation(s)
- Adam P Klausner
- Department of Surgery/Division of Urology, Virginia Commonwealth University School of Medicine, PO BOX 980118, Richmond, VA, 23298-0118, USA,
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Speich JE, Wilson CW, Almasri AM, Southern JB, Klausner AP, Ratz PH. Carbachol-induced volume adaptation in mouse bladder and length adaptation via rhythmic contraction in rabbit detrusor. Ann Biomed Eng 2012; 40:2266-76. [PMID: 22614640 DOI: 10.1007/s10439-012-0590-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
Abstract
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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Affiliation(s)
- John E Speich
- Department of Mechanical & Nuclear Engineering, Virginia Commonwealth University, Richmond, 23284-3015, USA.
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Speich JE, Southern JB, Henderson S, Wilson CW, Klausner AP, Ratz PH. Adjustable passive stiffness in mouse bladder: regulated by Rho kinase and elevated following partial bladder outlet obstruction. Am J Physiol Renal Physiol 2011; 302:F967-76. [PMID: 22205227 DOI: 10.1152/ajprenal.00177.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Detrusor smooth muscle (DSM) contributes to bladder wall tension during filling, and bladder wall deformation affects the signaling system that leads to urgency. The length-passive tension (L-T(p)) relationship in rabbit DSM can adapt with length changes over time and exhibits adjustable passive stiffness (APS) characterized by a L-T(p) curve that is a function of both activation and strain history. Muscle activation with KCl, carbachol (CCh), or prostaglandin E(2) at short muscle lengths can increase APS that is revealed by elevated pseudo-steady-state T(p) at longer lengths compared with prior T(p) measurements at those lengths, and APS generation is inhibited by the Rho Kinase (ROCK) inhibitor H-1152. In the current study, mouse bladder strips exhibited both KCl- and CCh-induced APS. Whole mouse bladders demonstrated APS which was measured as an increase in pressure during passive filling in calcium-free solution following CCh precontraction compared with pressure during filling without precontraction. In addition, CCh-induced APS in whole mouse bladder was inhibited by H-1152, indicating that ROCK activity may regulate bladder compliance during filling. Furthermore, APS in whole mouse bladder was elevated 2 wk after partial bladder outlet obstruction, suggesting that APS may be relevant in diseases affecting bladder mechanics. The presence of APS in mouse bladder will permit future studies of APS regulatory pathways and potential alterations of APS in disease models using knockout transgenetic mice.
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Affiliation(s)
- John E Speich
- Mechanical and Nuclear Engineering, Virginia Commonwealth University, 401 West Main St., Richmond, VA 23284-3015, USA.
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Tuna BG, Bakker ENTP, VanBavel E. Smooth muscle biomechanics and plasticity: relevance for vascular calibre and remodelling. Basic Clin Pharmacol Toxicol 2011; 110:35-41. [PMID: 21902815 DOI: 10.1111/j.1742-7843.2011.00794.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Blood vessel structure and calibre are not static. Rather, vessels remodel continuously in response to their biomechanical environment. Vascular calibre is dictated by the amount, composition and organization of the elastic extracellular matrix. In addition, the amount and organization of contractile smooth muscle cell (SMC) also need to be regulated. The SMCs are organized such that maximum contractile force generally occurs at diameters slightly below the diameter at full dilation and physiological pressure. Thus, in a remodelling vessel, not only the matrix but also the SMCs need to undergo structural adaptation. Surprisingly little is known on the adaptation of SMC contractile properties in the vasculature. The purpose of this review is to explore this SMC plasticity in the context of vascular remodelling. While not much work on this has been carried out on blood vessels, SMC plasticity is more extensively studied on other hollow structures such as airway and bladder. We therefore include studies on bladder and airway SMCs because of their possible relevance for vascular SMC behaviour. Here, plasticity is thought to form an adaptation allowing maintained function despite large volume changes. In blood vessels, the general match of active and passive diameter-tension relations suggests that SMC plasticity is part of normal vascular physiological adaptation. Vascular SMCs display similar processes and forms of adaptation as seen in nonvascular SMCs. This may become particularly relevant under strong vasoconstriction, when inward cytoskeletal adaptation possibly prevents immediate full dilation. This may contribute to structural inward remodelling as seen in hypertension and flow reduction.
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Affiliation(s)
- Bilge Guvenc Tuna
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Almasri AM, Ratz PH, Speich JE. Length adaptation of the passive-to-active tension ratio in rabbit detrusor. Ann Biomed Eng 2010; 38:2594-605. [PMID: 20387122 DOI: 10.1007/s10439-010-0021-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 03/19/2010] [Indexed: 02/04/2023]
Abstract
The passive and active length-tension (L-T (p) and L-T (a)) relationships in airway, vascular, and detrusor smooth muscles can adapt with length changes and/or multiple contractions. The present objectives were to (1) determine whether short-term adaptation at one muscle length shifts the entire L-T (a) curve in detrusor smooth muscle (DSM), (2) compare adaptation at shorter versus longer lengths, and (3) determine the effect of adaptation on the T (p)/T (a) ratio. Results showed that multiple KCl-induced contractions on the descending limb of the original L-T (a) curve adapted DSM strips to that length and shifted the L-T (a) curve rightward. Peak T (a) at the new length was not different from the original peak T (a), and the L-T (p) curve shifted rightward with the L-T (a) curve. Multiple contractions on the ascending limb increased both T (a) and T (p). In contrast, multiple contractions on the descending limb increased T (a) but decreased T (p). The T (p)/T (a) ratio on the original descending limb adapted from 0.540 +/- 0.084 to 0.223 +/- 0.033 (mean +/- SE, n = 7), such that it was not different from the ratio of 0.208 +/- 0.033 at the original peak T (a) length, suggesting a role of length adaptation may be to maintain a desirable T (p)/T (a) ratio as the bladder fills and voids over a broad DSM length range.
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Affiliation(s)
- Atheer M Almasri
- Department of Mechanical Engineering, Virginia Commonwealth University, 401 West Main Street, P.O. Box 843015, Richmond, VA 23284-3015, USA
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Ratz PH, Speich JE. Evidence that actomyosin cross bridges contribute to "passive" tension in detrusor smooth muscle. Am J Physiol Renal Physiol 2010; 298:F1424-35. [PMID: 20375119 DOI: 10.1152/ajprenal.00635.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Contraction of detrusor smooth muscle (DSM) at short muscle lengths generates a stiffness component we termed adjustable passive stiffness (APS) that is retained in tissues incubated in a Ca(2+)-free solution, shifts the DSM length-passive tension curve up and to the left, and is softened by muscle strain and release (strain softened). In the present study, we tested the hypothesis that APS is due to slowly cycling actomyosin cross bridges. APS and active tension produced by the stimulus, KCl, displayed similar length dependencies with identical optimum length values. The myosin II inhibitor blebbistatin relaxed active tension maintained during a KCl-induced contraction and the passive tension maintained during stress-relaxation induced by muscle stretch in a Ca(2+)-free solution. Passive tension was attributed to tension maintaining rather than tension developing cross bridges because tension did not recover after a rapid 10% stretch and release as it did during a KCl-induced contraction. APS generated by a KCl-induced contraction in intact tissues was preserved in tissues permeabilized with Triton X-100. Blebbistatin and the actin polymerization inhibitor latrunculin-B reduced the degree of APS generated by a KCl-induced contraction. The degree of APS generated by KCl was inhibited to a greater degree than was the peak KCl-induced tension by rhoA kinase and cyclooxygenase inhibitors. These data support the hypothesis that APS is due to slowly cycling actomyosin cross bridges and suggest that cross bridges may play a novel role in DSM that uniquely serves to ensure proper contractile function over an extreme working length range.
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Affiliation(s)
- Paul H Ratz
- Departments of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614, USA.
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