Neuromuscular morphometry of the vaginal wall in women with anterior vaginal wall prolapse

Evaluation of Neuromuscular Morphometry of the Vaginal Wall Using Protein Gene Product 9.5 (Pgp 9.5) and Smooth Muscle α-Actin (Sma) in Patients with Posterior Vaginal Wall Prolapse

Background and Objectives: This study aims to compare the neuromuscular structure of the vagina in women with posterior vaginal wall prolapse with the neuromuscular structure of the vagina in women without prolapse, to determine the difference, and to demonstrate the role of neuromuscular structure in the physiopathology of prolapse. Materials and Methods: In this prospective study, women aged between 40 and 75 years who had not undergone any vaginal surgery and had not undergone any abdominal prolapse surgery were included. Thirty-one women diagnosed with rectocele on examination were included in the study group. Thirty-one patients who underwent vaginal intervention and hysterectomy for reasons other than rectocele (colposcopy, conization, etc.) without anterior or posterior wall prolapse were included in the control group. Biopsy material was obtained from the epithelium of the posterior wall of the vagina, including the fascia that fits the Ap point. Immunohistochemical staining with Protein Gene Product 9.5 and smooth muscle α-actin was performed in the pathology laboratory. The epithelial thickness measurement and smooth muscle density parameters obtained with these immunohistochemical stainings were compared between the two groups. The collected data were analyzed using the SPSS 23 package program. p values less than 0.05 were considered statistically significant. Results: In the control group, muscle thickness and the number of nerves per mm2 of fascia were statistically significantly higher than in the study group (p < 0.05). Conclusions: We found that smooth muscle tissue and the number of nerves per mm2 of fascia were decreased in posterior vaginal wall prolapse compared to the general population. Based on the correlation coefficients, age was the parameter that most affected the degree of prolapse, followed by parity, number of live births, and number of vaginal deliveries.

Smooth Muscle Organization and Nerves in the Rat Vagina: A First Look Using Tissue Clearing and Immunolabeling

Smooth muscle fibers within the vagina, as well as the nerve fibers that contribute to their control mechanisms, are important for the maintenance and alteration of vaginal length and tone. Vaginal smooth muscle (VaSM) is typically described as being arranged into two distinct concentric layers: an inner circular muscular layer and an outer longitudinal muscular layer. However, the distribution of VaSM oriented in the longitudinal direction (LD) and circumferential direction (CD) has never been quantified. In this study, tissue clearing and immunohistochemistry were performed so that the VaSM, and surrounding nerves, within whole rat vaginas ([Formula: see text]) could be imaged without tissue sectioning, preserving the three-dimensional architecture of the organs. Using these methods, the vagina was viewed through the full thickness of the muscularis layer, from the distal to the proximal regions. The VaSM orientation in the proximal and distal regions and the VaSM content along the LD and CD were quantified. Additionally, a qualitative assessment of vaginal nerves was performed. When compared using a permuted version of the Watson [Formula: see text] test, the orientation of VaSM in the proximal and distal regions were found to be significantly different in 4 of the 6 imaged rat vaginas ([Formula: see text]). While the distal vagina contained a similar amount of VaSM oriented within [Formula: see text] of the LD and within [Formula: see text] of the CD, the proximal vagina contained significantly more VaSM oriented towards the LD than towards the CD. Nerve fibers were found to be wavy, running both parallel and perpendicular to vascular and non-vascular smooth muscle within the vagina. Micro-structural analyses, like the one conducted here, are necessary to understand the physiological function and pathological changes of the vagina.

Search for the G spot: microvessel and nerve mapping of the paraurethral anterior vaginal wall

INTRODUCTION AND HYPOTHESIS

Orgasm and other sexual responses such as pain, arousal and lubrication may be mediated by nerve fibers and vessels in the lamina propria and muscularis of the vaginal wall, in which case the number of nerve fibers and vessels would be associated with sexual functions. The aim of the study is to map the distribution of nerves and vessels in the anterior vaginal wall along the paraurethral region in a systematic fashion.

METHODS

Specimens were taken from women with anterior vaginal wall prolapse undergoing colporrhaphy anterior repair. All specimens were mapped in a standard way starting 15 mm proximal to the external urethral orifice. Selected blocks of samples were immunohistochemically stained: actin, smooth muscle Ab-1 and S100 Protein Ab-1. The numbers of microvessels and nerves in the lamina propria and muscularis were counted in five consecutive high-power fields of a light microscope. Pairwise comparisons of proximal, distal, right and left paravaginal microvessel and nerve fiber density were analyzed with paired-sample t-test or Wilcoxon signed-rank test.

RESULTS

Vaginal nerve fibers in the lamina propria and muscularis have a fairly even distribution in the anterior vaginal wall. Vaginal small vessel vascularization and microvascularization are also evenly distributed, with no concentrated site along the paraurethral region of the anterior vaginal wall.

CONCLUSIONS

Nerve fiber, nerve bundle, microvessel and small vessel densities in the lamina propria and muscularis were fairly regular, with no concentrated site on the paraurethral region of the anterior vaginal wall.

Role of Estrogens in the Size of Neuronal Somata of Paravaginal Ganglia in Ovariectomized Rabbits

We aimed to determine the role of estrogens in modulating the size of neuronal somata of paravaginal ganglia. Rabbits were allocated into control (C), ovariectomized (OVX), and OVX treated with estradiol benzoate (OVX + EB) groups to evaluate the neuronal soma area; total serum estradiol (E2) and testosterone (T) levels; the percentage of immunoreactive (ir) neurons anti-aromatase, anti-estrogen receptor (ERα, ERβ) and anti-androgen receptor (AR); the intensity of the immunostaining anti-glial cell line-derived neurotrophic factor (GDNF) and the GDNF family receptor alpha type 1 (GFRα1); and the number of satellite glial cells (SGCs) per neuron. There was a decrease in the neuronal soma size for the OVX group, which was associated with low T, high percentages of aromatase-ir and neuritic AR-ir neurons, and a strong immunostaining anti-GDNF and anti-GFRα1. The decrease in the neuronal soma size was prevented by the EB treatment that increased the E2 without affecting the T levels. Moreover, there was a high percentage of neuritic AR-ir neurons, a strong GDNF immunostaining in the SGC, and an increase in the SGCs per neuron. Present findings show that estrogens modulate the soma size of neurons of the paravaginal ganglia, likely involving the participation of the SGC.

Does the vaginal wall become thinner as prolapse grade increases?

INTRODUCTION AND HYPOTHESIS

The pathophysiology of prolapse is not well understood. However, two main theories predominate: either the fibromuscular layer of the vagina develops a defect/tears away from its supports, or its tissues are stretched and attenuated. The aim of this study was to assess how vaginal wall thickness (VWT) is related to vaginal prolapse.

METHODS

The study group comprised 243 women with symptomatic prolapse recruited from the Outpatient Department of a tertiary referral centre for urogynaecology. A history was taken and women were examined to determine their POP-Q score. Using a previously validated technique, ultrasonography was used to measure the mean VWT at three anatomical sites on the anterior and posterior walls. Scores were then compared using t tests, the Kruskal-Wallis test and the Friedman test.

RESULTS

The mean age of the patients was 59.7 years (SD 12.0 years range 38 - 84 years). For each measurement VWT reduced as prolapse grade increased until the prolapse extended beyond the hymen. Women with grade 3 prolapse had a significantly higher mean VWT than women with grade 1 or 2 contained prolapse. Menopause status did not have a significant effect on the VWT.

CONCLUSIONS

VWT is lower in women with vaginal prolapse until the prolapse extends beyond the hymen and then VWT is thicker and comparable with women without prolapse. This may be explained by changes in the vaginal tissue including reduction of collagen, elastin and smooth muscle, as well as fibrosis in exposed tissues, rather than by defects in the vagina.

In vitro differentiation of endometrial regenerative cells into smooth muscle cells: Α potential approach for the management of pelvic organ prolapse

Pelvic organ prolapse (POP), is a common condition in parous women. Synthetic mesh was once considered to be the standard of care; however, the use of synthetic mesh is limited by severe complications, thus creating a need for novel approaches. The application of cell-based therapy with stem cells may be an ideal alternative, and specifically for vaginal prolapse. Abnormalities in vaginal smooth muscle (SM) play a role in the pathogenesis of POP, indicating that smooth muscle cells (SMCs) may be a potential therapeutic target. Endometrial regenerative cells (ERCs) are an easily accessible, readily available source of adult stem cells. In the present study, ERCs were obtained from human menstrual blood, and phase contrast microscopy and flow cytometry were performed to characterize the morphology and phenotype of the ERCs. SMC differentiation was induced by a transforming growth factor β1-based medium, and the induction conditions were optimized. We defined the SMC characteristics of the induced cells with regard to morphology and marker expression using transmission electron microscopy, western blot analysis, immunocytofluorescence and RT-PCR. Examining the expression of the components of the Smad pathway and phosphorylated Smad2 and Smad3 by western blot analysis, RT-PCR and quantitative PCR demonstrated that the 'TGFBR2/ALK5/Smad2 and Smad3' pathway is involved, and both Smad2 and Smad3 participated in SMC differentiation. Taken together, these findings indicate that ERCs may be a promising cell source for cellular therapy aimed at modulating SM function in the vagina wall and pelvic floor in order to treat POP.

The impact of prolapse mesh on vaginal smooth muscle structure and function

OBJECTIVE

To evaluate the impact of prolapse meshes on vaginal smooth muscle structure (VaSM) and function, and to evaluate these outcomes in the context of the mechanical and textile properties of the mesh.

DESIGN

Three months following the implantation of three polypropylene prolapse meshes with distinct textile and mechanical properties, mesh tissue explants were evaluated for smooth muscle contraction, innervation, receptor function, and innervation density.

SETTING

Magee-Womens Research Institute at the University of Pittsburgh.

POPULATION

Thirty-four parous rhesus macaques of similar age, parity, and pelvic organ prolapse quantification (POP-Q) scores.

METHODS

Macaques were implanted with mesh via sacrocolpopexy. The impact of Gynemesh(™)  PS (Ethicon; n = 7), Restorelle(®) (Coloplast; n = 7), UltraPro(™) parallel and UltraPro(™) perpendicular (Ethicon; n = 6 and 7, respectively) were compared with sham-operated controls (n = 7). Outcomes were analysed by Kruskal-Wallis ANOVA, Mann-Whitney U-tests and multiple regression analysis (P < 0.05).

MEAN OUTCOME MEASURES

Vaginal tissue explants were evaluated for the maximum contractile force generated following muscle, nerve, and receptor stimulation, and for peripheral nerve density.

RESULTS

Muscle myofibre, nerve, and receptor-mediated contractions were negatively affected by mesh only in the grafted region (P < 0.001, P = 0.002, and P = 0.008, respectively), whereas cholinergic and adrenergic nerve densities were affected in the grafted (P = 0.090 and P = 0.008, respectively) and non-grafted (P = 0.009 and P = 0.005, respectively) regions. The impact varied by mesh property, as mesh stiffness was a significant predictor of the negative affect on muscle function and nerve density (P < 0.001 and P = 0.013, respectively), whereas mesh and weight was a predictor of receptor function (P < 0.001).

CONCLUSIONS

Mesh has an overall negative impact on VaSM, and the effects are a function of mesh properties, most notably, mesh stiffness.

TWEETABLE ABSTRACT

Prolapse mesh affects vaginal smooth muscle.

Changes in elastin density in different locations of the vaginal wall in women with pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

The purpose of this study was to analyze the histomorphometric properties of the vaginal wall in women with pelvic organ prolapse (POP).

METHODS

In 15 women undergoing surgery for POP, full-thickness biopsies were collected at two different sites of location from the anterior and/or posterior vaginal wall. Properties of the precervical area (POP-Q point C/D) were compared with the most distal portion of the vaginal wall (POP-Q point Ba/Bp) using histological staining and immunohistochemistry. The densities of total collagen fibers, elastic fibers, smooth muscle cells, and blood vessels were determined by combining high-resolution virtual imaging and computer-assisted digital image analysis.

RESULTS

The mean elastin density was significantly decreased in the lamina propria and muscularis layer of the vaginal wall from the most distal portion of the prolapsed vaginal wall compared with the precervical area. This difference was statistically significant in the lamina propria for both anterior (8.4 ± 1.2 and 12.1 ± 2.0, p = 0.048) and posterior (6.8 ± 0.5 and 10.1 ± 1.4, p = 0.040) locations, and in the muscularis for the anterior (5.2 ± 0.4 and 8.4 ± 1.2, p = 0.009) vaginal wall. There were no statistically significant differences in the mean densities of collagen fibers, smooth muscle cells or blood vessels between the two locations.

CONCLUSIONS

In this study, we observed changes in elastin density in two different locations of the vaginal wall from women with POP. The histomorphometric properties of the vaginal wall can be variable from one place to another in the same patient. This result supports the existence of most vulnerable locations within the vaginal wall and the potential benefit of site-specific prolapse surgery.

Histology of the vaginal wall in women with pelvic organ prolapse: a literature review

INTRODUCTION AND HYPOTHESIS

The pathophysiology of pelvic organ prolapse (POP) is incompletely understood. The purpose of this study is to describe the current knowledge about histology of the vaginal wall and its possible involvement in the pathogenesis of pelvic organ prolapse.

METHODS

Eligible studies were selected through a MEDLINE search covering January 1986 to December 2012. The research was limited to English-language publications.

RESULTS

Investigations of changes in the vaginal tissue that occur in women with genital prolapse are currently still limited and produced contrary results. The heterogeneity of the patients and the control groups in terms of age, parity and hormonal status, of the localization of biopsies and the histological methods as well as the lack of validation of the quantification procedures do not allow clear and definitive conclusions to be drawn.

CONCLUSIONS

This review shows that current knowledge of the histological changes observed in women with POP are inconclusive and relatively limited. More studies are needed in this specific field to better understand the mechanisms that lead to POP.