Role of Sling Integrity in the Restoration of Leak Point Pressure in the Rat Vaginal Sling Model

Hijaz, Adonis; Daneshgari, Firouz; Huang, Xinlei; Bena, James; Liu, Guiming; Saffore, Lateef; Damaser, Margot S.

doi:10.1097/01.ju.0000164721.52278.29

Cited by 13 publications

(15 citation statements)

References 16 publications

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“…As previously demonstrated, the median LPP values were similarly and significantly increased in rats in the intact and cut sling groups compared with the rats in the sham surgery group (27.9 cm H 2 O, interquartile range [IQR] 26.1–32.7; 24.9 cm H 2 O, IQR 23.3–34.1; 20.7 cm H 2 O, IQR 17.6–24.6; respectively, P > .001). 16 …”

Section: Resultsmentioning

confidence: 99%

“…5–7 Driven by those clinical findings, we have previously demonstrated that the LPPs were similarly and significantly increased in animals with intact and cut slings compared with sham surgery animals. 16 No statistically significant differences were found in the LPPs between the rats with cut or intact slings.…”

Section: Commentmentioning

confidence: 87%

“…16,17 Using that model, we have previously reported the results of a randomized trial in which rats with SUI were assigned to either placement of an intact suburethral sling (intact sling) or a suburethral sling that was immediately cut after placement at the suburethral portion (cut sling), or vaginal dissection and needle passage without sling placement (sham surgery). 18 Examination of the LPPs in these rats at 6 weeks after surgery revealed that the rats with either a cut or an intact sling had equally and significantly improved LPPs compared with the rats that had undergone sham surgery.…”

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confidence: 99%

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Collagen Remodeling and Suburethral Inflammation Might Account for Preserved Anti-incontinence Effects of Cut Polypropylene Sling in Rat Model

Chen

Hijaz

Drazba

et al. 2009

Urology

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OBJECTIVES To determine whether the inflammatory responses or collagen remodeling in suburethral tissue could have contributed to the preserved anti-incontinence effects of a cut polypropylene sling. METHODS Stress urinary incontinence was created in 60 age-matched female Sprague-Dawley rats that were subsequently randomized into 3 equal-size groups according to surgical procedure: placement of a vaginal suburethral sling, placement of a vaginal suburethral sling in which the suburethral portion of the sling was immediately cut, and sham surgery without placement of the sling. In a previous study, the leak point pressure measurements were obtained on these rats 6 weeks after surgery. The rats were then killed, the urethrovaginal tissue was harvested (cross-section of the entire urethra and anterior vagina) from 30 animals (10 from each experimental group), and the tissue was stained with hematoxylin-eosin and Masson’s trichrome for histopathologic studies and picrosirius red for collagen fibers. RESULTS As previously published, the median leak point pressures were similarly and significantly increased in the rats in the intact and cut sling groups compared with those in the sham surgery group. The inflammatory mediators and interstitial edema were similarly increased in the intact and cut sling specimens compared with the sham surgery specimens. Under polarized light, picrosirius red-stained specimens from the sham surgery animals appeared to be composed of collagen that predominately birefringed red to yellow (typical of type I collagen). The picrosirius red-stained cut and intact sling specimens appeared to contain collagen fibers that predominately birefringed green (typical of type III collagen). CONCLUSIONS Histologic changes, including inflammation, localized edema, and differential collagen remodeling, might contribute to the preserved anti-incontinence mechanisms of cut or intact polypropylene slings observed clinically.

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Section: Resultsmentioning

confidence: 99%

Section: Commentmentioning

confidence: 87%

mentioning

confidence: 99%

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Collagen Remodeling and Suburethral Inflammation Might Account for Preserved Anti-incontinence Effects of Cut Polypropylene Sling in Rat Model

Chen

Hijaz

Drazba

et al. 2009

Urology

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“…Studies on the effect of birth trauma and menopause on the continence mechanism are lacking because of the restricted availability of human tissue. In this study, we used virgin female mice [7, 8] to analyze the effects of vaginal distension (VD; simulated birth trauma) [9, 10] and hormone deficiency (these two factors known to be important in SUI) on the vagina and urethra. VD simulates the effects of birth trauma [9] and ovariectomy (OVX) simulates the hormone deficiency that occurs after menopause [7].…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effect of Vaginal Trauma and Ovariectomy in a Murine Model of Stress Urinary Incontinence: Upregulation of Urethral Nitric Oxide Synthases and Estrogen Receptors

Chen

Lin

et al. 2014

Mediators of Inflammation

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The molecular mechanisms underlying stress urinary incontinence (SUI) are unclear. We aimed to evaluate the molecular alterations in mice urethras following vaginal trauma and ovariectomy (OVX). Twenty-four virgin female mice were equally distributed into four groups: noninstrumented control; vaginal distension (VD) group; OVX group; and VD + OVX group. Changes in leak point pressures (LPPs), genital tract morphology, body weight gain, plasma 17β-estradiol level and expressions of neuronal nitric oxide synthase (nNOS), induced nitric oxide synthase (iNOS), and estrogen receptors (ERs—ERα and ERβ) were analyzed. Three weeks after VD, the four groups differed significantly in genital size and body weight gain. Compared with the control group, the plasma estradiol levels were significantly decreased in the OVX and VD + OVX groups, and LPPs were significantly decreased in all three groups. nNOS, iNOS, and ERα expressions in the urethra were significantly increased in the VD and VD + OVX groups, whereas ERβ expression was significantly increased only in the VD + OVX group. These results show that SUI following vaginal trauma and OVX involves urethral upregulations of nNOS, iNOS, and ERs, suggesting that NO- and ER-mediated signaling might play a role in the synergistic effect of birth trauma and OVX-related SUI pathogenesis.

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“…Over the last decade, animal models of SUI have increasingly been used to understand the pathogenesis of SUI [4,5]. Vaginal distension (VD) [6,7] and pudendal nerve transection (PNT) [8,9] have been used for creation of SUI in rats. Leak-point pressure (LPP) is used clinically to evaluate urethral competence and to determine the etiology of urine leakage.…”

Section: Introductionmentioning

confidence: 99%

Recovery of Continence Function following Simulated Birth Trauma Involves Repair of Muscle and Nerves in the Urethra in the Female Mouse

Lin

Liu

et al. 2010

European Urology

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Background The natural history and the mechanisms behind the alteration of vaginal distension (VD) in a mouse model are not clear. Objective We examined the temporal sequelae of VD and pudendal nerve transection (PNT) on leak-point pressure (LPP) and the muscular and nerve components of the urethra in mice. Design, setting, and participants Seventy-two virgin female C57BL/6 mice were equally distributed into three groups. The VD group underwent VD for 1 h. The PNT group received bilateral PNT. A control group underwent sham VD. Intervention Each group was divided into four subgroups of six mice for measurement of LPP at 0, 4, 10, and 20 d after VD or PNT. Measurements LPP was measured. Morphology and neurofilament-immunoreactive nerve of the urethra were assessed. Results and limitations LPP was decreased at 0, 4, and 10 d but not at 20 d after VD. Decreased LPP persisted to 20 d in the PNT group. The external urethral striated muscle appeared wavy and disrupted in three mice at 0 d, in two mice at 4 d, in one mouse at 10 d, and in one mouse in 20 d after VD. The density of neurofilament-immunoreactive nerve in the urethra was reduced at 4 and 10 d after VD, but not at 20 d, and at 4, 10, and 20 d after PNT compared with the corresponding values of the sham VD group. The limitation of this animal model is that the pelvic floor structure of the mouse is different from that of female humans. Therefore, results of this study should be carefully applied to human subjects. Conclusions VD causes reversible stress urinary incontinence in female mice. Recovery of continence function following VD is associated with repair of the external urethral sphincter and reinnervation of the urethra. This mouse model will be useful for mechanistic investigation and targeting of therapeutic intervention by taking advantage of genetic manipulation.

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Role of Sling Integrity in the Restoration of Leak Point Pressure in the Rat Vaginal Sling Model

Abstract: An intact suburethral portion is not a requirement for sling effectiveness in the rat model of stress urinary incontinence. However, the sling procedure decreases bladder compliance. This may explain the observed voiding dysfunction associated with sling procedures.

Cited by 13 publications

References 16 publications

Collagen Remodeling and Suburethral Inflammation Might Account for Preserved Anti-incontinence Effects of Cut Polypropylene Sling in Rat Model

Collagen Remodeling and Suburethral Inflammation Might Account for Preserved Anti-incontinence Effects of Cut Polypropylene Sling in Rat Model

Synergistic Effect of Vaginal Trauma and Ovariectomy in a Murine Model of Stress Urinary Incontinence: Upregulation of Urethral Nitric Oxide Synthases and Estrogen Receptors

Recovery of Continence Function following Simulated Birth Trauma Involves Repair of Muscle and Nerves in the Urethra in the Female Mouse

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