Expression of extracellular matrix-remodeling proteins is altered in vaginal tissue of premenopausal women with severe pelvic organ prolapse

Unveiling novel regulatory mechanisms of miR-5195-3p in pelvic organ prolapse pathogenesis†

Pelvic organ prolapse is a condition that significantly affects women's quality of life. The pathological mechanism of pelvic organ prolapse is not yet fully understood, and its pathogenesis is often caused by multiple factors, including the metabolic imbalance of the extracellular matrix. This study aims to investigate the role of miR-5195-3p, a microRNA, in the pathology of pelvic organ prolapse and its regulatory mechanism. Using various molecular biology techniques such as real-time reverse transcription Polymerase Chain Reaction (PCR), fluorescence in situ hybridization, immunohistochemistry, and Western blot, miR-5195-3p expression was examined in vaginal wall tissues obtained from pelvic organ prolapse patients. Results revealed an up-regulation of miR-5195-3p expression in these tissues, showing a negative correlation with the expression of extracellular matrix-related proteins. Further analysis using bioinformatics tools identified Lipoxygenase (LOX) as a potential target in pelvic organ prolapse. Dual luciferase reporter gene experiments confirmed LOX as a direct target of miR-5195-3p. Interestingly, regulating the expression of LOX also influenced the transforming growth factor β1 signaling pathway and had an impact on extracellular matrix metabolism. This finding suggests that miR-5195-3p controls extracellular matrix metabolism by targeting LOX and modulating the TGF-β1 signaling pathway. In conclusion, this study unveils the involvement of miR-5195-3p in the pathological mechanism of pelvic organ prolapse by regulating extracellular matrix metabolism through the LOX/TGF-β1 axis. These findings reveal new mechanisms in the pathogenesis of pelvic organ prolapse, providing a theoretical foundation and therapeutic targets for further research on pelvic organ prolapse treatment.

Genetic Etiology in Pelvic Organ Prolapse: Role of Connective Tissue Homeostasis, Hormone Metabolism, and Oxidative Stress

Background: Pelvic organ prolapse (POP) has become a common health problem among the aging population and affects an increasing number of elderly women worldwide. Studies within family and twin pairs provided strong evidence for the contribution of genetic factors to POP. Given the incomplete penetrance, polygenic traits, and small effect sizes of each variant in complex diseases, it is not always easy to evaluate the genetic susceptibility and molecular mechanisms involved in POP. Objectives: This review intends to comprehensively summarize the current studies on genetic variants associated with POP. Methods: We performed a comprehensive review to summarize the genetic findings from genome-linkage studies, genome-wide association studies, candidate association studies, and gene expression analyses. Results: We summarized genetic variants associated with connective tissue homeostasis, hormone metabolism, and oxidative stress, which were potentially related to the pathophysiology of POP. We also reviewed the limited polygenic risk score (PRS) studies generated for each individual's genetic risk stratification and its integration into clinical risk factors for disease prediction. Conclusions: This pooled analysis provides moderate epidemiological credibility for associations of these genetic variants with POP to bridge the gap between genetic research and clinical medicine towards understanding the genetic etiology of POP. It also highlights the potential of PRS as a risk prediction model.

The difference in extracellular matrix metabolism in women with and without pelvic organ prolapse: A systematic review and meta-analysis

BACKGROUND

Studies on the changes of extracellular matrix (ECM) in pelvic organ prolapse (POP) are still controversial.

OBJECTIVE

To identify the changes in the ECM in POP patients.

SEARCH STRATEGY

Comprehensive searching in Embase, PubMed, Web of Science and the Cochrane Library was carried out until 23 February 2023.

SELECTION CRITERIA

Studies comparing the protein levels of ECM-related components between women with and without POP.

DATA COLLECTION AND ANALYSIS

Quality and risk of bias were assessed using the Agency for Healthcare Research and Quality assessment. Indicators were pooled with random or fixed effect meta-analysis based on heterogeneity and sub-grouped analysed by the biopsy site.

MAIN RESULTS

Thirty cross-sectional studies were included, comprising 840 POP cases and 755 controls. Overall results showed that the expression of type III collagen (COLIII) and several matrix metalloproteinases (MMP-1, -2 and -9) were increased, whereas those of type I collagen (COLI), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) were decreased in patients with POP. Subgroup analysis showed that the expression of COLIII in the anterior vaginal wall (AVW) and COLIII, MMP-2 and -9 in the uterosacral ligament (USL) were consistent with the overall results. However, the expression of COLI and MMP-1 in the AVW showed no difference and the expression of COLI and MMP-1 in the USL is still controversial based on current studies.

CONCLUSIONS

Patients with POP have lower expression of COLI and TIMP-1 and higher expression of COLIII and MMPs compared with non-POP cases, but further studies are required to investigate in specified anatomical sites.

An Improved Understanding of the Pathophysiology of Pelvic Organ Prolapse: A 3D In Vitro Model under Static and Mechanical Loading Conditions

The suboptimal outcomes of pelvic organ prolapse (POP) surgery illustrate the demand for improved therapies. However, their development is hampered by the limited knowledge on the cellular pathophysiology of POP. Current investigations, that are limited to tissues and 2D in vitro models, provide highly inconclusive results on how the extracellular matrix (ECM) metabolism and fibroblasts are affected in POP. This study uses a physiologically relevant 3D in vitro model to investigate the cellular pathophysiology of POP by determining the differences between POP and non-POP fibroblasts on ECM metabolism, proliferation, and fibroblast-to-myofibroblast (FMT) transition. This model, based on the synthetic and biomimetic polyisocyanide hydrogel, enables the incorporation of mechanical loading, which simulates the forces exerted on the pelvic floor. Under static conditions, 3D cultured POP fibroblasts are less proliferative, undergo FMT, and exhibit lower collagen and elastin contents compared to non-POP fibroblasts. However, under mechanical loading, the differences between POP and non-POP fibroblasts are less pronounced. This study contributes to the development of more comprehensive models that can accurately mimic the POP pathophysiology, which will aid in an enhanced understanding and may contribute to improved therapies in the future.

Roles and mechanisms of biomechanical-biochemical coupling in pelvic organ prolapse

Pelvic organ prolapse (POP) is a significant contributor to hysterectomy among middle-aged and elderly women. However, there are challenges in terms of dedicated pharmaceutical solutions and targeted interventions for POP. The primary characteristics of POP include compromised mechanical properties of uterine ligaments and dysfunction within the vaginal support structure, often resulting from delivery-related injuries. Fibroblasts secrete extracellular matrix, which, along with the cytoskeleton, forms the structural foundation that ensures proper biomechanical function of the fascial system. This system is crucial for maintaining the anatomical position of each pelvic floor organ. By systematically exploring the roles and mechanisms of biomechanical-biochemical transformations in POP, we can understand the impact of forces on the injury and repair of these organs. A comprehensive analysis of the literature revealed that the extracellular matrix produced by fibroblasts, as well as their cytoskeleton, undergoes alterations in patient tissues and cellular models of POP. Additionally, various signaling pathways, including TGF-β1/Smad, Gpx1, PI3K/AKT, p38/MAPK, and Nr4a1, are implicated in the biomechanical-biochemical interplay of fibroblasts. This systematic review of the biomechanical-biochemical interplay in fibroblasts in POP not only enhances our understanding of its underlying causes but also establishes a theoretical foundation for future clinical interventions.

Dysregulated wound healing in the pathogenesis of urogynecologic mesh complications

To test the hypothesis that dysregulated wound healing is associated with Urogynecologic mesh complications, we collected vaginal cell secretions using vaginal swabs after polypropylene mesh implantation in patients with (N = 39) and without (N = 40) complication. A customized multiplex immunoassay measured markers of inflammation (MCP-1, IGFBP-1, IL-2, IL-10, IL-17, PDGF-BB, bFGF, IL-1b, IL-6, IL-12p70, TNF-α), neuroinflammation (IL-1RA, TGF-β, IL-15, IL-18, IL-3, M-CSF), angiogenesis (VEGF), and matrix proteins (fibronectin, tenasin c, thrombospondin-2, lumican) between groups. Patients with complications were younger, heavier, implanted with mesh longer, and more likely to be ever smokers. A 5 kg/m2 BMI increase and ever-smoking were associated with a 2.4-fold and sixfold increased risk of complication, respectively. Patients with the highest tertile of bFGF, fibronectin, thrombospondin-2, TNF-β, or VEGF had an odds ratio (OR) of 11.8 for having a mesh complication while ≥ 3 elevated had an OR of 237 while controlling for age, BMI, and smoking. The highest tertile of bFGF, thrombospondin-2, and fibronectin together perfectly indicated a complication (P < 0.0001). A receiver-operator curve for high bFGF, thrombospondin-2, and fibronectin showed excellent discrimination between complications and controls (AUC 0.87). These data provide evidence of dysregulated wound healing in mesh complications. Modifiable factors provide potential targets for patient counseling and interventions.

4D DIA-PRM proteomic study identifying modulated pathways and biomarkers associated with pelvic organ prolapse

Pelvic organ prolapse (POP) is a highly disabling condition that negatively affects the quality of life of millions of women worldwide. However, the underlying mechanisms associated with the development and progression of the disease remain poorly understood. Here, an untargeted four-dimensional data-independent acquisition (4D DIA)-based proteomics approach was applied to vaginal wall tissue samples from POP (n = 19) and control (n = 8) patients to identify potential diagnostic biomarker(s) for POP and examine the molecular mechanisms underlying the disease. Of the 5713 tissue proteins that were detected, 1957 proteins were significantly changed in POP patients. Further bioinformatics analysis revealed that multiple biological processes including protein digestion & absorption, retrograde endocannabinoid signaling, tyrosine metabolism, and nucleotide metabolism were significantly enriched and associated with the pathogenesis of POP. Interestingly, 16 of these differentially expressed proteins associated with four pathways were also identified by targeted parallel reaction monitoring (PRM) proteomics analysis on the same 27 tissue samples. Changes in 94 % (15/16) of these proteins were consistent with the 4D DIA data. Furthermore, most proteins displayed good diagnostic accuracy with high area under the curve (AUC) values (AUC＞0.8). Specifically, five proteins including ELN, COL6A2, ENTPD1, AOC3, and COX7A2 distinguished between POP and control patients with very high accuracy (AUC ≥ 0.95) in both 4D DIA and PRM analyses, and may therefore be potential diagnostic biomarkers for POP. In summary, the present study not only provided several potential biomarker(s) for effective POP diagnosis, but extended our knowledge of the key regulatory pathways associated with the disease.

Potential molecular targets for intervention in pelvic organ prolapse

Pelvic organ prolapse (POP) is a concerning gynecological benign illness in middle-aged and senior women. Its etiology is complex, the incidence rate is high, symptoms are clinically subjective, and its influence tends to be polarized. At present, for those who need medical treatment, whether surgical or non-surgical, complications cannot be ignored, and treatment effect needs to be optimized. However, there is a lack of accurate molecular biological interventions for the prevention, diagnosis, progression delay, and treatment of POP. Here, we reviewed the current state of understanding of the molecular mechanisms and factors associated with POP etiology. These factors include cyclins, matrix metal peptidases/tissue inhibitors of metalloproteinases, microRNAs, homeobox A11, transforming growth factor β1, insulin-like growth factor 1, fibulin 5, lysyl oxidase-like 1, oxidative stress, inflammatory response, estrogen, and other potential biomarkers associated with POP. In addition, relevant molecular targets that may be used to intervene in POP are summarized. The aim of this review was to provide more information to identify accurate potential biomarkers and/or molecular targets for the prevention, diagnosis, progression delay, and treatment of POP, with the goal of improving medical treatment for patients at-risk for POP or having POP. Continued research is needed to identify additional details of currently accepted molecular mechanisms and to identify additional mechanisms that contribute to POP.

Emerging trends on the mechanism of pelvic organ prolapse from 1997 to 2022: visualization and bibliometric analysis

Objective

At present, there is no feature description of the mechanism of pelvic organ prolapse (POP) in the literature. This study aimed to map the emerging trends regarding the mechanism of POP from inception to 2022 by bibliometric analysis and to analyze its research hotspots and frontiers.

Methods

We downloaded pertinent publications from inception to 2022 from the Web of Science Core Collection (WoSCC) on 30 June 2022. The data were then examined using the Bibliometrix program in R (Version 4.1.0), CiteSpace software, the Online Analysis Platform of Literature Metrology (https://bibliometric.com), and a bibliometrix online interface.

Results

A total of 290 qualified records on the mechanism of POP were identified and included in the analysis. The most productive journal was International Urogynecology Journal. Bump RC and Olsen AL were the most cited authors. Extracellular matrix, collagen, apoptosis, elastin, oxidative stress, gene expression, matrix metalloproteinase, and tissue engineering were among the 25 most relevant terms. According to the analysis of trending topics, tissue engineering has become a new research hotspot.

Conclusion

Extracellular matrix remodeling, oxidative stress and apoptosis are the three main directions for studying the mechanism of POP. In addition, tissue engineering has become a new research hotspot. In the future, in-depth research on the interaction between different mechanisms will be carried out, and attempts will be made to combine biomimetic materials and seed cells to achieve the regeneration and reconstruction of POP-related organs.

Polyisocyanides as a substrate to trigger vaginal fibroblast functioning in an in vitro model for prolapse repair

Pelvic organ prolapse (POP) is the descent of the bladder, uterus, and/or rectum into the vagina. POP is associated with altered vaginal fibroblast functionality and connective tissue composition in the vaginal wall. The results of surgical intervention are poor, which may be related to the lack of true restoration of the connective tissue. An innovative treatment addresses tissue repair after surgery by the introduction of a bioactive supplement that enhances the healing process through collagen and elastin deposition. As a novel strategy, we first studied the effects in an in vitro model. Here, we investigate how the presence of cell binding GRGDS (RGD) peptides on the highly biomimetic polyisocyanide (PIC) gel facilitates and promotes the function of primary vaginal fibroblasts isolated from a POP patient. Fibroblast function was analyzed in terms of morphology, proliferation, and extracellular matrix (ECM) deposition and remodeling. RGD modification of the gel facilitated cell spread and proliferation. Quantitative outcomes of the ECM content indicated increased production of collagen and elastin by fibroblasts on gels with the highest RGD density. The in vitro results suggest that PIC-RGD hydrogel application may translate into improved connective tissue healing in the pelvic floor, which is essential for its use as a regeneration promoting additive in surgery.

Is there an association between pelvic organ prolapse and oxidative stress? A systematic review

Introduction and hypothesis

The pathophysiology of pelvic organ prolapse (POP) has not been fully elucidated, although accumulating evidence suggests that oxidative stress is involved. The present systematic review comprehensively discusses this topic.

Methods

The PubMed/Medline, Scopus, and Web of Science databases were searched for relevant studies published up to May 2021. This systematic review was registered in the PROSPERO database (registration number CRD42021242240). Two independent researchers screened and selected articles that fulfilled predefined inclusion criteria, performed a quality assessment, and extracted the relevant data. Of 901 original articles retrieved, 8 fulfilled the selection criteria and were included in the review.

Results

Elevated levels of markers of oxidative stress, such as advanced glycation end products, hydroxynonenal and hydroxydeoxyguanosine, were found in various parts of the pelvic floor of patients with POP. Accordingly, the levels of glutathione peroxidase and superoxide dismutase, known as major antioxidant enzymes, were reduced, compared to those in healthy controls. Levels of two other markers (mitofusin 2 and nuclear factor erythroid derived 2) also support hypotheses suggesting the involvement of oxidative stress in POP.

Conclusions

In the literature available, an association between oxidative stress and pelvic organ prolapse was confirmed.

The polymorphisms of extracellular matrix-remodeling genes are associated with pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

Extracellular matrix (ECM) synthesis and metabolism abnormalities may influence the pelvic supporting system and lead to the occurrence and development of pelvic organ prolapse (POP). Genetic polymorphisms of such related genes have been increasingly studied. This study aims to explore the association between the single-nucleotide polymorphisms (SNPs) of genes encoding ECM processing enzymes (a disintegrin and metalloproteinase with thrombospondin motifs [ADAMTSs]), ECM degrading enzymes (matrix metalloproteinases [MMPs]) and their tissue inhibitors of metalloproteinase (TIMPs), and POP.

METHODS

We conducted an association study including 48 women with POP at stages III and IV and 48 women without prolapse in Chinese groups. SNPs were identified using the target region sequencing technique. We performed Fisher's exact tests to assess the association between SNPs and POP in the unadjusted model and logistic regression analysis in the adjusted model, adjusting for delivery and pregnancy.

RESULTS

There was a significant association between TIMP2 SNP rs2277698 (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.16-0.82; P = 0.015), ADAMTS13 SNP rs149586801 (OR, 0.18; 95% CI, 0.05-0.69; P = 0.012), and ADAMTS1 SNPs rs370850 and rs422803 (OR, 3.71; 95% CI, 1.35-10.15; P = 0.011 for both), rs402007, rs428785, rs434857, and rs445784 (OR, 2.18; 95% CI, 1.05-4.56; P = 0.038 for the four), and POP in the adjusted model.

CONCLUSION

TIMP2, ADAMTS13, and ADAMTS1 might be candidate genes for POP. Our results provide preliminarily new evidence for future investigation of these genes in the pathophysiology of POP.

Role of fibulin-5 insufficiency and prolapse progression on murine vaginal biomechanical function

The vagina plays a critical role in supporting the pelvic organs and loss of support leads to pelvic organ prolapse. It is unknown what microstructural changes influence prolapse progression nor how decreased elastic fibers contributes to vaginal remodeling and smooth muscle contractility. The objective for this study was to evaluate the effect of fibulin-5 haploinsufficiency, and deficiency with progressive prolapse on the biaxial contractile and biomechanical function of the murine vagina. Vaginas from wildtype (n = 13), haploinsufficient (n = 13), and deficient mice with grade 1 (n = 9) and grade 2 or 3 (n = 9) prolapse were explanted for biaxial contractile and biomechanical testing. Multiaxial histology (n = 3/group) evaluated elastic and collagen fiber microstructure. Western blotting quantified protein expression (n = 6/group). A one-way ANOVA or Kruskal-Wallis test evaluated statistical significance. Pearson's or Spearman's test determined correlations with prolapse grade. Axial contractility decreased with fibulin-5 deficiency and POP (p < 0.001), negatively correlated with prolapse grade (ρ = - 0.80; p < 0.001), and positively correlated with muscularis elastin area fraction (ρ = - 0.78; p = 0.004). Circumferential (ρ = 0.71; p < 0.001) and axial (ρ = 0.69; p < 0.001) vaginal wall stresses positively correlated with prolapse grade. These findings demonstrated that fibulin-5 deficiency and prolapse progression decreased vaginal contractility and increased vaginal wall stress. Future work is needed to better understand the processes that contribute to prolapse progression in order to guide diagnostic, preventative, and treatment strategies.

Mesenchymal stem cell transplantation for vaginal repair in an ovariectomized rhesus macaque model

BACKGROUND

Current surgical therapies for pelvic organ prolapse (POP) do not repair weak vaginal tissue and just provide support; these therapies may trigger severe complications. Stem cell-based regenerative therapy, due to its ability to reconstruct damaged tissue, may be a promising therapeutic strategy for POP. The objective of this study is to evaluate whether mesenchymal stem cell (MSC) therapy can repair weak vaginal tissue in an ovariectomized rhesus macaque model.

METHODS

A bilateral ovariectomy model was established in rhesus macaques to induce menopause-related vaginal injury. Ten bilaterally ovariectomized rhesus macaques were divided into two groups (n=5/group): the saline group and the MSC group. Three months after ovariectomy, saline or MSCs were injected in situ into the injured vaginal wall. The vaginal tissue was harvested 12 weeks after injection for histological and biochemical analyses to evaluate changes of extracellular matrix, microvascular density, and smooth muscle in the vaginal tissue. Biomechanical properties of the vaginal tissue were assessed by uniaxial tensile testing. Data analysis was performed with unpaired Student's t test or Mann-Whitney.

RESULTS

Twelve weeks after MSC transplantation, histological and biochemical analyses revealed that the content of collagen I, elastin, and microvascular density in the lamina propria of the vagina increased significantly in the MSC group compared with the saline group. And the fraction of smooth muscle in the muscularis of vagina increased significantly in the MSC group. In addition, MSC transplantation improved the biomechanical properties of the vagina by enhancing the elastic modulus.

CONCLUSION

Vaginal MSC transplantation could repair the weak vaginal tissue by promoting extracellular matrix ingrowth, neovascularization, and smooth muscle formation and improve the biomechanical properties of the vagina, providing a new prospective treatment for POP.

Transforming Growth Factor Beta 1 and p44/42 Expression in Cardinal Ligament Tissues of Patients with Pelvic Organ Prolapse

Background

Pelvic organ prolapse (POP) is a disease associated with collagen loss and decreased fibroblast proliferation. Transforming growth factor beta 1 (TGF-β1) controls collagen synthesis and degradation in pelvic connective tissue. Although the p44/42 MAPK pathway has been implicated in collagen production and extracellular matrix disorders, its expression in POP remains unknown. This study aimed to investigate TGF-β1 and p44/42 expression in cardinal ligament tissues in patients with POP.

Material/Methods

Cardinal ligament tissues were obtained from 30 patients with POP (POP group) and 30 patients with benign gynecological disorders who had undergone total hysterectomy (control group). The clinical characteristics of the 2 groups were summarized. Immunohistochemical staining and western blotting analysis were performed to measure the expression of TGF-β1, p44/42, phospho-p44/42, MMP9, TIMP1, caspase 3, collagen I, and collagen III in the cardinal ligament tissues.

Results

Patients with POP had significantly lower TGF-β1 and phospho-p44/42 levels than did control patients (P<0.05). The expression of TIMP1, collagen I, and collagen III was significantly lower, and the expression of MMP9 and caspase 3 was significantly higher in the POP group than in the control group (P<0.05). Moreover, the expression of phospho-p44/42 was positively correlated with the expression of TGF-β1, collagen I, and collagen III.

Conclusions

The expression levels of phospho-p44/42 and TGF-β1 were decreased in patients with POP and were positively correlated with collagen expression. Low levels of TGF-β1 and phospho-p44/42 expression in patients with POP may be associated with the occurrence of POP.

Mechanical stress influences the morphology and function of human uterosacral ligament fibroblasts and activates the p38 MAPK pathway

Introduction and hypothesis

Pelvic organ prolapse (POP) is a common condition in older women that affects quality of life. Mechanical injury of the pelvic floor support system contributes to POP development. In our study, we aimed to examine the mechanical damage to human uterosacral ligament fibroblasts (hUSLFs) to preliminarily explore the mechanism of mechanical transduction in POP.

Methods

hUSLFs were derived from POP and non-POP patients. Mechanical stress was induced by the FX-5000 T-cell stress loading system. Student’s t-test was used for comparisons between different groups.

Results

We found that hUSLFs from POP patients were larger and longer than those from non-POP patients and exhibited cytoskeleton F-actin rearrangement. Collagen I and III expression levels were lower and matrix metalloproteinase 1 (MMP1) levels were higher in POP patients than in non-POP patients. Additionally, the apoptosis rate was significantly increased in POP patients compared to non-POP patients. After mechanical stretching, hUSLFs underwent a POP-like transformation. Cells became longer, and the cytoskeleton became thicker and rearranged. The extracellular matrix (ECM) was remodelled because of the upregulation of collagen I and III expression and downregulation of MMP1 expression. Mechanical stress also induced hUSLF apoptosis. Notably, we found that the p38 MAPK pathway was activated by mechanical stretching.

Conclusions

Mechanical stress induced morphological changes in ligament fibroblasts, leading to cytoskeleton and ECM remodelling and cell apoptosis. p38 MAPK might be involved in this process, providing novel insights into the mechanical biology of and possible therapies for this disease.

Mesenchymal stem cell-based bioengineered constructs enhance vaginal repair in ovariectomized rhesus monkeys

Transvaginal meshes repair for treating pelvic organ prolapse (POP) was halted by the U. S. Food and Drug Administration (FDA) because they can lead to severe complications. Therefore, investigations of new therapeutic strategies are urgently needed. Cell-based regenerative therapy holds great promise for the repair and restoration of damaged tissue. Here, we generated a bioengineered graft by seeding human umbilical cord mesenchymal stem cells (HUMSCs) on bioscaffolds to reconstruct the damaged vagina. In the in vitro study, HUMSCs proliferated well and the density was appropriate after 5 days of culture. Besides, we demonstrated that the differentiation potential of HUMSCs was maintained with external growth factor stimulation. The complete transcriptomic profile of HUMSCs revealed that HUMSCs cultured on grafts produced significantly higher levels of proangiogenic cytokines than cells cultured in tissue culture plates (TCPs). Three months after implantation of the bioengineered grafts into ovariectomized (OVX) rhesus monkeys via sacrocolpopexy, extracellular matrix reorganization, large muscle bundle formation, angiogenesis and, mechanical properties of the vagina were enhanced. To our knowledge, this is the first demonstration of the utility of stem cell-based bioengineered grafts for repairing damaged vaginal tissue in rhesus monkeys. These results elucidate a new approach for vagina repair and provide new ideas for treating POP.

Bone marrow stem cells secretome accelerates simulated birth trauma-induced stress urinary incontinence recovery in rats

Stress urinary incontinence (SUI) is defined as involuntary urine leakage during physical activities that increase the intra-abdominal pressure on the bladder. We studied bone marrow stem cell (BMSC) secretome-induced activation of anterior vaginal wall (AVW) fibroblasts and its ability to accelerate SUI recovery following vaginal distention (VD) in a rat model of birth trauma using BMSC-conditioned medium (BMSC-CM) and concentrated conditioned medium (CCM). BMSC-CM enhanced the proliferation, migration, and collagen synthesizing abilities of fibroblasts. Differentially expressed genes in BMSC-CM-induced fibroblasts were mainly enriched for cell adhesion, extracellular fibril organization and angiogenesis. Treatment with the JAK2 inhibitor AG490 reversed BMSC-CM-induced activation of the JAK2/STAT4 pathway. Periurethral injection with BMSC-CCM markedly enhanced the abdominal leak point pressure (LPP) in rats after VD. Histological analysis revealed increased numbers of fibroblasts, improved collagen fibers arrangement and elevated collagens content in the AVW of rats receiving BMSC-CCM. These findings suggest the BMSC secretome activates AVW fibroblasts and contributes to the functional and anatomic recovery of simulated birth trauma-induced SUI in rats.

SMAD2, SMAD3 and TGF-β GENE expressions in women suffering from urge urinary incontinence and pelvic organ prolapse

We evaluated the changes in the levels of TGF-β and SMAD gene and protein expression in the uterosacral ligament (USL) of patients with concomitant pelvic organ prolapse (POP) and urgency urinary incontinence (UUI) to illuminate the pathophysiology of UUI. The TGF-β pathway is involved in collagen synthesis and degradation. The Transforming Growth Family-β (TGF-β) superfamily has essential intracellular signaling components, such as newly identified SMAD family members. We evaluated the changes in the levels of TGF-β and SMAD gene and protein expression in the USL of patients with concomitant pelvic organ prolapse (POP) and UUI. This study included 10 patients who had been diagnosed with POP and UUI in the study group and 14 asymptomatic women without complaints of POP and UUI in the control group. Biopsy samples were collected from bilateral USL tissues during vaginal or abdominal hysterectomy. Total RNA was extracted from USL tissue and analyzed by qPCR. The protein expression levels were also analyzed with ELISA. In UUI patients, SMAD3 and TGF-ß1 gene expression levels significantly decreased compared to the control patients (p = 0.008 and p = 0.006, respectively). SMAD2 mRNA levels did not differ between the study and control groups (p = 0.139). No differences was found in the levels of SMAD2, SMAD3, and TGF-ß1 protein expression between the two groups. The reduction in the gene and protein expression levels of SMAD3 and TGF-ß1 in women with UUI and lax uterosacral ligaments may indicate a causal link.Clinical trial registration: NCT04525105.

Expression of COX-2 and Nrf2/GPx3 in the anterior vaginal wall tissues of women with pelvic organ prolapse

PURPOSE

To evaluate COX-2 and Nrf2/GPx3 expressions in the lamina propria of the anterior vaginal wall tissues of women with and without pelvic organ prolapse (POP).

METHODS

Tissue samples of anterior vaginal wall were examined using HE staining, immuohistochemical staining and Western blot for the expressions of COX-2/PGE2, Nrf2/GPx3, MMP2, TIMP1, collagen I and collagen III (n = 35, per group).

RESULTS

Compared with control group, collagen fibers of the anterior vaginal wall were disorganized and discontinuous. Expressions of Nrf2, GPx3, TIMP1, collagen I and collagen III were found significantly lower in POP group (P < 0.05); while, expressions of COX-2, PGE2, and MMP2 were found significantly higher in POP group (P < 0.05). Statistically significant correlations of COX-2 and Nrf2/GPx3 were showed (P < 0.01).

CONCLUSION

We found that the interaction between inflammation and oxidative stress was closely related to the development of POP. This study demonstrates that COX-2 and Nrf2 pathways may be involved in pathogenesis of POP, as promising potential therapeutic targets and agents.

Single-cell transcriptome profiling of the vaginal wall in women with severe anterior vaginal prolapse

Anterior vaginal prolapse (AVP) is the most common form of pelvic organ prolapse (POP) and has deleterious effects on women's health. Despite recent advances in AVP diagnosis and treatment, a cell atlas of the vaginal wall in AVP has not been constructed. Here, we employ single-cell RNA-seq to construct a transcriptomic atlas of 81,026 individual cells in the vaginal wall from AVP and control samples and identify 11 cell types. We reveal aberrant gene expression in diverse cell types in AVP. Extracellular matrix (ECM) dysregulation and immune reactions involvement are identified in both non-immune and immune cell types. In addition, we find that several transcription factors associated with ECM and immune regulation are activated in AVP. Furthermore, we reveal dysregulated cell-cell communication patterns in AVP. Taken together, this work provides a valuable resource for deciphering the cellular heterogeneity and the molecular mechanisms underlying severe AVP.

Molecular mechanism of extracellular matrix disorder in pelvic organ prolapses

Pelvic organ prolapses (POP) notably reduces the quality of life in elderly populations due to bladder and bowel dysfunction, incontinence, and coital problems. Extracellular matrix (ECM) disorder is a pivotal event in the progression of POP, but to date, its specific underlying mechanism remains unclear. The ligaments of patients with POP and healthy controls were collected to compare the expression of Homeobox11 (HOXA11) and transforming growth factor β (TGF-β1) via immunohistochemical analysis. HOXA11 and TGF-β1 were overexpressed or knocked down in fibroblast cells to explore their effects on the expression of collagen and matrix metalloproteinases (MMPs). HOXA11 and TGF-β1 were greatly reduced in the ligaments of patients with POP. The overexpression and downregulation of HOXA11 and TGF-β1 can mediate ECM disorder via regulating expression of collagen (Col) and MMPs. In addition, HOXA11 and TGF-β1 exerted synergistic effect on the expression of Col and MMPs. The present study identified that HOXA11 and TGF-β1 serve critical roles in mediating ECM disorders, which may be of clinical significance for the diagnosis and treatment of patients with POP.

Evaluation of extracellular matrix protein expression and apoptosis in the uterosacral ligaments of patients with or without pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

This study aimed to compare the expression levels of extracellular matrix (ECM) and apoptosis proteins in the uterosacral ligament (USL) of patients with and without pelvic organ prolapse (POP).

METHODS

The USL were obtained from patients with POP-Q ≥ III (n = 35) and without POP (n = 20). Immunohistochemistry (IHC) staining and RT-qPCR were conducted to assess the protein and mRNA levels, respectively. The levels of type I collagen (COLI), type III collagen (COLIII), matrix metalloproteinase (MMP)1, MMP2, MMP9, tissue inhibitor of metalloproteinase (TIMP)1, TIMP2, estrogen receptor (ER)α, ERβ and apoptosis-related gene B cell lymphoma 2 (Bcl-2)-associated agonist of cell death (Bad) and Bcl-2-associated X (Bax) in the USL were analyzed.

RESULTS

The protein expression and mRNA levels of MMP2 and MMP9, mRNA levels of BAD and BAX, and protein expression of active cleaved-Caspase3 were significantly higher in the POP group. There were no evident differences in COLIII, MMP1 or ERβ expression at either the mRNA or protein level or in TIMP1, TIMP2 or Caspase3 by IHC between the two groups. However, obvious decreases in COLI and ERα were evident at both the mRNA and protein levels in the POP group, and the mRNA levels of TIMP1 and TIMP2 were also decreased compared to those of the control group.

CONCLUSION

ECM in the USL tissues of POP patients is remodeled compared with non-POP patients and is characterized by decreased synthesis and increased degradation of collagen; moreover, the levels of the main proteins involved in apoptosis are increased in POP tissue.

Extracellular Matrix Stiffness and Composition Regulate the Myofibroblast Differentiation of Vaginal Fibroblasts

Fibroblast to myofibroblast differentiation is a key feature of wound-healing in soft tissues, including the vagina. Vaginal fibroblasts maintain the integrity of the vaginal wall tissues, essential to keep pelvic organs in place and avoid pelvic organ prolapse (POP). The micro-environment of vaginal tissues in POP patients is stiffer and has different extracellular matrix (ECM) composition than healthy vaginal tissues. In this study, we employed a series of matrices with known stiffnesses, as well as vaginal ECMs, in combination with vaginal fibroblasts from POP and healthy tissues to investigate how matrix stiffness and composition regulate myofibroblast differentiation in vaginal fibroblasts. Stiffness was positively correlated to production of α-smooth muscle actin (α-SMA). Vaginal ECMs induced myofibroblast differentiation as both α-SMA and collagen gene expressions were increased. This differentiation was more pronounced in cells seeded on POP-ECMs that were stiffer than those derived from healthy tissues and had higher collagen and elastin protein content. We showed that stiffness and ECM content regulate vaginal myofibroblast differentiation. We provide preliminary evidence that vaginal fibroblasts might recognize POP-ECMs as scar tissues that need to be remodeled. This is fundamentally important for tissue repair, and provides a rational basis for POP disease modelling and therapeutic innovations in vaginal reconstruction.

Changes in β-Catenin Expression in the Anterior Vaginal Wall Tissues of Women With Pelvic Organ Prolapse: A Potential Pathophysiological Mechanism

OBJECTIVES

The purpose of this study was to investigate the expression of β-catenin in the lamina propria of the anterior vaginal wall of women with pelvic organ prolapse (POP) compared with the expression in the controls.

METHODS

Anterior vaginal wall tissues were obtained from women undergoing POP surgery for stage 3 or greater POP (POP group, n = 30; age, 58 ± 7.839 years), with a menopause rate of 70%, and from women without POP undergoing hysterectomy for benign indications (control group, n = 30; age, 54.7 ± 7.173 years), with a menopause rate of 50%. Hematoxylin and eosin staining and Masson trichrome staining were performed on anterior vaginal wall sections. β-Catenin, p-β-catenin, glycogen synthase kinase 3β (GSK3β), p-GSK3β, collagen I, collagen III, MMP2, MMP9, TIMP2, caspase 3, proliferating cell nuclear antigen, and cyclin D1 were evaluated using immunohistochemical analysis. Lamina propria tissues were obtained for Western blot analyses.

RESULTS

Hematoxylin and eosin staining and Masson trichrome staining showed that the collagen fibers were more disorganized and fragmented in the POP group than in the control group. In the POP samples, β-catenin (mean density, POP vs control, 0.43 ± 0.13 vs 0.58 ± 0.16), p-GSK3β, collagen I, collagen III, proliferating cell nuclear antigen, and cyclin D1 were downregulated in the lamina propria, whereas in the control group, p-β-catenin, TIMP2, and caspase 3 were downregulated (P < 0.05 for all). GSK3β was not different between the 2 groups (P > 0.05).

CONCLUSION

We demonstrated that decreased β-catenin may play an important role in the onset of POP by affecting collagen anabolism.

Neurovascular alterations of muscularis propria in the human anterior vaginal wall in pelvic organ prolapse

In the pathophysiology and progression of pelvic organ prolapse (POP), it has been demonstrated that there is a reorganisation of the muscularis propria of the anterior vaginal wall due to a phenotypic smooth muscle cell to myofibroblast switch. An abnormal deposition of collagen type III seems to be influenced by the involvement of advanced glycation end-products. The aim of the present study was to evaluate the hypothesis that this connective tissue remodelling could also be associated with neurovascular alterations of the muscularis in women with POP compared with control patients. We examined 30 women with POP and 10 control patients treated for uterine fibromatosis. Immunohistochemical analysis, using glial fibrillary acidic protein, S-100 protein, receptor tyrosine kinase, neurofilament and α-smooth muscle actin antibodies, was performed. S-100, receptor tyrosine kinase and neurofilament were also evaluated using Western blot analysis. We observed a decrease in all neurovascular-tested markers in nerve bundles, ganglia and interstitial cells of Cajal from POP samples as compared with controls. Even if the processes responsible for these morphological alterations are still not known, it is conceivable that collagen III deposition in the anterior vaginal wall affects not only the architecture of the muscle layer but could also modify the intramuscular neurovascularisation and account for an alteration of the neuromuscular plasticity of the layer.

Local oestrogen therapy modulates extracellular matrix and immune response in the vaginal tissue of post-menopausal women with severe pelvic organ prolapse

This study investigates the effect of local oestrogen therapy (LET) on the expression of proteins participating in collagen/elastin biogenesis and immune markers in vaginal tissues of post‐menopausal women with severe pelvic organ prolapse (POP). Vaginal biopsies were collected from the anterior vaginal wall of informed and consented 52 post‐menopausal women with severe POP undergoing total hysterectomy. Twenty‐nine of the 52 women were treated with LET (in the form of vaginal oestrogen cream or tablet), while the remaining 23 untreated patients served as the controls. This study was approved by Sinai Health System REB. Vaginal tissue specimens were analysed for gene and protein expression using real‐time RT‐PCR and Luminex assays, protein localization and immune cell infiltration were assessed by immunohistochemistry. Forty‐four cytokines were detected. We found that LET application: (a) significantly increased (P < 0.05) gene and protein expression levels of extracellular matrix (ECM) structural proteins, collagen and elastin, as well as the expression of ECM maturation enzyme BMP1; (b) decreased protein expression level of ECM degradation enzymes MMP1, MMP2 and MMP3 accompanied by an increase in their tissue inhibitors, TIMP1 and TIMP4; (c) significantly increased (P < 0.05) the gene and protein expression levels of 14 vaginal cytokines involved in leucocyte infiltration, which was confirmed by immunohistochemistry. Our results indicate that LET plays an important role in the activation of immune system within the local vaginal environment, limiting the undesirable ECM degradation, which supports the strengthening of vaginal ECM in post‐menopausal women, therefore resisting menopause/age‐related changes and inducing urogenital tract tissue regeneration.

Collagen changes in pelvic support tissues in women with pelvic organ prolapse

Pelvic organ prolapse is a group of diseases caused by weakened pelvic supportive tissue, but the pathophysiology is not completely understood. Collagen is one of the most important components of the extracellular matrix in connective tissue, as it maintains the supportive functions of the pelvic floor. Collagen I and III are two major subtypes in pelvic tissues. With conflicting results of different studies, changes of their content and ratio are still disputed. The structure of collagen fibrils of pelvic organ prolapse patients become loose, disorderly and discontinuous and become stiffer than control group. Strong mechanical stress and imbalance matrix metalloproteinases /tissue-derived inhibitors of metalloproteinases can lead to collagen anabolism abnormalities causing changes of collagen content and structure. These changes are inter-influenced and are involved by multiple signaling pathways, including TGF-β/Smad, AGE/RAGE, MAPK, PI3K/AKT, and NF-κB. Collagen changes, including content, morphologic and biomechanical changes and catabolism abnormalities, can destroy the supportive function of the pelvic floor and are closely related to the development of pelvic organ prolapse. Epidemiological data also show a genetic predisposition to collagen changes. Research about collagen changes in the pelvic floor supportive tissues is limited and controversial. Small sample sizes and different recruitment criteria, biopsy sites, and research methods make comparisons between various studies difficult. More research concerning collagen changes is needed to better understand the pathogenesis of pelvic organ prolapse.

Genome‑wide DNA methylation analysis of uterosacral ligaments in women with pelvic organ prolapse

Pelvic organ prolapse (POP) is an increasingly serious health problem that impairs quality of life and is caused by multiple additive genetic and environmental factors. As the uterosacral ligaments (ULs) provide primary support for the pelvic organs, it was hypothesized that disruption of these ligaments (as a result of aberrant methylation) may lead to a loss of support and eventually contribute to POP. In the present study, whether there are any aberrant methylations in the ULs of patients with POP compared to those of controls was investigated. Genomic DNA was isolated from the ULs of five women with POP and four women without POP, as controls, undergoing hysterectomy for benign conditions. An Illumina Infinium Methylation EPICBeadChips Infinium Human Methylation 850 K bead array was used to investigate the total methylation in the ULs. There were 3,723 differentially methylated CpG sites (Δβ<0.14; P<0.05), including 3,576 hypermethylation and 147 hypomethylation sites in the ULs of patients with POP compared with the normal controls. There were more hypermethylated CpG sites, but a high ratio of hypomethylation between CpG islands and the N-shelf; in the gene structure, there was more hypermethylation than hypomethylation in TSS1500 and the 5′ untranslated region. Gene ontology analysis demonstrated that these differentially methylated genes were associated with ‘cell morphogenesis’, ‘extracellular matrix’, ‘cell junction’, ‘protein binding’ and ‘guanosine triphosphatase activity’. Several significant pathways were identified, including ‘focal adhesion’ and ‘extracellular matrix-receptor interaction pathway’. This study provides evidence that there are differences in genome-wide DNA methylation between ULs in menopausal women with and without POP, and that epigenetic mechanisms may partly contribute to POP pathogenesis.

The role of ADAMTS-2, collagen type-1, TIMP-3 and papilin levels of uterosacral and cardinal ligaments in the etiopathogenesis of pelvic organ prolapse among women without stress urinary incontinence

OBJECTIVE(S)

To investigate the potential role of 'a disintegrin-like and metalloproteinase with thrombospondin type motifs-2 (ADAMTS-2), collagen type-1, tissue inhibitor of metalloproteinases-3 (TIMP-3) and papilin' levels in the uterosacral ligament (USL) and cardinal ligament (CL) of the uterus on the etiopathogenesis of pelvic organ prolapse (POP) among postmenopausal women without stress urinary incontinence (SUI).

STUDY DESIGN

A total of 45 postmenopausal women, 22 diagnosed as POP stage III-IV and 23 age- and body mass index (BMI)-matched controls referred for hysterectomy due to POP or benign gynecological disease, respectively, were recruited prospectively for our study. The biopsies of the USL and CL were obtained during hysterectomy. ADAMTS-2, collagen type-1, TIMP-3 and papilin levels were determined by enzyme-linked immunosorbent assay (ELISA) method after tissue homogenization. We excluded patients who smoked or presented with SUI.

RESULTS

There were no differences in terms of demographic features including age, BMI, obesity, duration of menopause, gravidity, parity, delivery modes and family history for POP between the POP and non-POP groups. Significant differences in the levels of ADAMTS-2, collagen type-1, TIMP-3 and papilin of USL were noted among the groups. Females with POP had lower levels of ADAMTS-2, collagen type-1, TIMP-3 and papilin in the USL compared to non-POP females. All investigated markers in the CL were also decreased in the POP group, but this relationship was not statistically significant. When age, duration of menopause, gravidity, parity and obesity were taken as covariates, only the USL papilin levels were negatively predictive for the development of POP.

CONCLUSION(S)

ADAMTS-2, collagen type-1, TIMP-3 and papilin levels of the USL play essential roles in the etiopathogenesis of POP among postmenopausal women without SUI. Moreover, significantly decreased USL papilin levels in females with POP suggest the importance of the USL and the impact of papilin on the development of POP.

Immunolocalization of Advanced Glycation End Products, Mitogen Activated Protein Kinases, and Transforming Growth Factor-β/Smads in Pelvic Organ Prolapse

Collagen and matrix metalloproteinases (MMP) play a pivotal role in the pathophysiology of Pelvic Organ Prolapse (POP) as a switch between type I and III collagen together with a simultaneous activation of MMPs have been observed in the vaginal wall. The aim of this study was to evaluate the Advanced Glycation End (AGE) products, ERK1/2 and transforming growth factor (TGF)-β/Smad pathway expression in muscularis propria in women with POP compared with control patients. We examined 20 patients with POP and 10 control patients treated for uterine fibromatosis. Immunohistochemical analysis using AGE, RAGE, ERK1/2, Smads-2/3, Smad-7, MMP-3, and collagen I-III, TIMP, and α-SMA were performed. Smad-2/3, Smad-7, AGE, ERK1/2, p-ERK, and p-Smad3 were also evaluated using Western-blot analysis. POP samples from the anterior vaginal wall showed disorganization of the normal muscularis architecture. In POP samples, AGE, ERK1/2, Smad-2/3, MMP-3, and collagen III were upregulated in muscularis whereas in controls, Smad-7 and collagen I were increased. The receptor for AGEs (RAGE) was mild or absent both in controls and prolapse. We demonstrated the involvement of these markers in women with POP but further studies are required to elucidate if the overexpression of these molecules could play a crucial role in the pathophysiology of POP disease.

Effect of puerarin on collagen metabolism of fibroblasts in pelvic tissue of women with pelvic organ prolapse

The aim of the present study was to investigate the protective effect of puerarin on pelvic organ prolapse (POP) and the underlying mechanisms that regulate the metabolism of human parametrial ligament fibroblasts (HPLFs). HPLFs obtained from the pelvic tissue of patients with (n=10) or without (n=8) POP during hysterectomy were isolated by enzymatic digestion and subsequently identified by immunocytochemistry in a previous study of the authors. Following this, cultured HPLFs were treated with 0.01, 0.10 or 1.00 mmol/l puerarin, followed by detection of proliferation rate by Cell Counting kit‑8 assay. Following incubation with puerarin for 48 h, mRNA and protein expression levels of tissue inhibitor of metalloproteinase‑1 (TIMP‑1), matrix metalloproteinase (MMP)‑2 and ‑9, and collagen (COL)I and III in HPLFs were quantified by reverse transcription‑quantitative polymerase chain reaction, and western blot and gelatin zymography analyses, respectively. MMP‑2 and ‑9 expression levels were increased, whereas expression levels of TIMP‑1, and COL I and III were decreased, in patients with POP compared with healthy controls. Following puerarin treatment, the expression levels of TIMP‑1, and COL I and III were enhanced, whereas MMP‑2 and ‑9 were inhibited. In conclusion, the present study demonstrated evidence increased degradation of the extracellular matrix in pelvic tissues of patients with POP compared with controls, and the protective effect of puerarin against POP via its anti‑degradation effect on collagen. These results provide evidence for puerarin as a novel approach for the treatment of POP.

Transcriptional Regulation of Connective Tissue Metabolism Genes in Women With Pelvic Organ Prolapse

OBJECTIVE

The aim of this study was to compare differences in expressions and relationships between key genes involved in extracellular matrix metabolism and tissue cellularity in women with and without pelvic organ prolapse (POP).

METHODS

A total of 80 biopsies (anterior cuff, posterior cuff, and/or leading edge) were obtained from 30 women: n = 10 premenopausal without POP (controls), n = 10 premenopausal with POP, and n = 10 postmenopausal with POP. Quantitative reverse-transcriptase polymerase chain reaction was used to assess gene expression of bone morphogenetic protein 1 (BMP1), collagen types I (COL1) and III (COL3), relaxin family peptide receptor 1 (RXFP1), matrix metallopeptidase 2, and TIMP metallopeptidase inhibitors 2 and 3. Hematoxylin and eosin staining was used to assess cellularity of the connective tissue layer. Kruskal-Wallis test, Mann-Whitney U test, Pearson correlation, or linear regression analyses were used, as appropriate.

RESULTS

Bone morphogenetic protein 1 expression was significantly up-regulated in patients with POP compared with controls. Bone morphogenetic protein 1 expression was correlated with COL1 expression in all groups but only correlated with TIMP metallopeptidase inhibitor 3 expression in controls. Similarly, COL3 expression was correlated with RXFP1 expression in women with POP but not in controls. The degree of dependence (slope of the regression line) between COL1 and COL3 expressions was significantly elevated in premenopausal women with POP compared with the other 2 groups. The slopes between COL1-COL3, COL3-matrix metallopeptidase 2, COL1-RXFP1, and COL3-RXFP1 expressions were significantly lower in postmenopausal women compared with premenopausal women with POP. No differences were found in overall tissue cellularity.

CONCLUSIONS

Bone morphogenetic protein 1 expression may play a significant role in the pathophysiology of POP. The finding that BMP1 expression was correlated with COL1 expression in all groups suggests a conserved association between BMP1 and collagen synthesis in the vaginal wall. The elevated slope between COL1 and COL3 expressions may be associated with early (premenopausal) development of POP. The expression of RXFP1 in postmenopausal women and its altered intergene regulation suggests a role for RXFP1 in connective tissue metabolism outside pregnancy.

Role of transforming growth factor β‑1 in the pathogenesis of pelvic organ prolapse: A potential therapeutic target

The present study aimed to reveal the metabolic alterations of the extracellular matrix (ECM) in uterosacral ligament (USL) with pelvic organ prolapse (POP) and to explore the role of transforming growth factor-β1 (TGF-β1) in pathogenesis of POP. For this purpse, 60 participants who underwent hysterectomy for benign indications were enrolled, 30 of which had symptomatic POP (grade II, III or IV) and composed the POP group, and the other 30 had asymptomatic POP (grade I or less) and served as the controls. Collagen fibers, elastin, matrix metalloproteinase (MMP)-2/9, tissue inhibitor of matrix metalloproteinases (TIMP)-2 and TGF-β1 were examined by Masson's trichrome staining, immunohistochemistry and RT-qPCR using USL biopsies. In vitro, human USL fibroblasts (hUSLFs) were primary cultured, pre-treated with recombinant TGF-β1 (0, 5, or 10 ng/ml) and then subjected to cyclic mechanical stretching (CMS; 0 or 5,333 με strain). Changes in the expression levels of collagen type I/III, elastin, TIMP-2, MMP-2/9 and Smad were detected. Our results revealed that at the tissue level, the expression of collagen fibers, elastin, TIMP-2 and TGF-β1 was significantly reduced in the POP group, while the activities of MMP-2/9 were significantly upregulated, compared with the control group. Statistical analysis indicated that the mRNA expression of TGF-β1 inversely correlated with the severity of POP partially. Our in vitro experimental data demonstrated that a CMS of 5333 με strain promoted the degradation of ECM proteins, inhibited the synthesis of TIMP-2, and upregulated the proteolytic activities of MMP-2/9. Pre-treatment with TGF-β1 attenuated the loss of ECM by stimulating the synthesis of TIMP-2 and inhibiting the activities of MMP-2/9 through the TGF-β1/Smad3 signaling pathway. On the whole, our data indicate that the reduced anabolism and increased catabolism of ECM proteins in USL are the pathological characteristics of POP. TGF-β1 not only has a specific value in predicting the severity of POP, but should also be considered as a novel therapeutic target for POP.

Ovine multiparity is associated with diminished vaginal muscularis, increased elastic fibres and vaginal wall weakness: implication for pelvic organ prolapse

Pelvic Organ Prolapse (POP) is a major clinical burden affecting 25% of women, with vaginal delivery a major contributing factor. We hypothesised that increasing parity weakens the vagina by altering the extracellular matrix proteins and smooth muscle thereby leading to POP vulnerability. We used a modified POP-quantification (POP-Q) system and a novel pressure sensor to measure vaginal wall weakness in nulliparous, primiparous and multiparous ewes. These measurements were correlated with histological, biochemical and biomechanical properties of the ovine vagina. Primiparous and multiparous ewes had greater displacement of vaginal tissue compared to nulliparous at points Aa, Ap and Ba and lower pressure sensor measurements at points equivalent to Ap and Ba. Vaginal wall muscularis of multiparous ewes was thinner than nulliparous and had greater elastic fibre content. Collagen content was lower in primiparous than nulliparous ewes, but collagen organisation did not differ. Biomechanically, multiparous vaginal tissue was weaker and less stiff than nulliparous. Parity had a significant impact on the structure and function of the ovine vaginal wall, as the multiparous vaginal wall was weaker and had a thinner muscularis than nulliparous ewes. This correlated with "POP-Q" and pressure sensor measurements showing greater tissue laxity in multiparous compared to nulliparous ewes.

Low extracellular lysyl oxidase expression is associated with poor prognosis in patients with prostate cancer

Remodeling of the extracellular matrix (ECM), which is induced by lysyl oxidase (LOX), has been demonstrated to accompany tumor progression; however, the association between LOX expression levels and the malignant behavior of prostate cancer (Pca) remains unclear. The present study aimed to analyze the tumor-associated expression profile of LOX in patients with Pca and to evaluate its potential prognostic value. In the form of a retrospective study, the expression patterns of LOX and collagen I were analyzed in patients with benign prostate hyperplasia and Pca by immunohistochemical examination. The results demonstrated that, with the initiation and progression of Pca, the expression levels of LOX and collagen I were closely associated with Gleason score and tumor stage. In addition, although LOX was expressed in cancer and non-cancer tissues, the differential expression pattern observed in the ECM of Pca cells may indicate that LOX is an important molecule that affects the progression of this disease. Therefore, LOX expression level in the ECM may function as an independent predictor of Pca.

Matrix Metalloproteinase-1 Expression in Women With and Without Pelvic Organ Prolapse: A Systematic Review and Meta-analysis

This meta‐analysis was conducted to estimate the association between matrix metalloproteinase‐1 (MMP‐1) expression and pelvic organ prolapse (POP) in women. Relevant studies published before 6 December 2015 were identified by searching PubMed, Ovid, EBSCO, and EMBASE. A total number of five case–control studies, including 182 POP cases and 192 controls, were identified. The results indicated that women without POP had a lower MMP‐1 level of expression compared with women with POP (odds ratio = 0.54, 95% confidence interval: 0.43–0.67, P = 0.000). After stratification by biopsy site, ethnicity, or menopausal status, this finding was also confirmed in the subgroup analysis with no significant changes. Egger's linear regression test revealed a potential publication bias (P = 0.028). The findings of our study indicate that women who suffer from POP have a higher expression level of MMP‐1 than women without POP.

Changes in muscularis propria of anterior vaginal wall in women with pelvic organ prolapse

The objective of this study was to evaluate the morphological and immunohistochemical alterations of tissue removed from the upper third of anterior vaginal wall in a sample group of the female population presenting homogenous risk factors associated with Pelvic Organ Prolapse (POP). The case study consisted of 14 patients with POP and there were 10 patients in the control group. Patient selection was carried on the basis of specific criteria and all of the patients involved in the study presented one or more of the recognized POP risk factors. Samples were taken from POP patients during vaginal plastic surgery following  colpohysterectomy, and from control patients during closure of the posterior fornix following hysterectomy. Samples were processed for histological and  immunohistochemical analyses for Collagen I and Collagen III, α-Smooth Muscle Actin (α-SMA), Platelet-Derived-Growth-Factor (PDGF), matrix metalloproteinase 3 (MMP3), Caspase3. Immunofluorescence analyses for Collagen I and III and PDGF were also carried out. In prolapsed specimens our results show a disorganization of smooth muscle cells that appeared to have been displaced by an increased collagen III deposition resulting in rearrangement of the muscularis propria architecture. These findings suggest that the increase in the expression of collagen fibers in muscularis could probably due to a phenotypic switch resulting in the dedifferentiation of smooth muscle cells into myofibroblasts. These alterations could be responsible for the compromising of the dynamic functionality of the pelvic floor.

Static Mechanical Loading Influences the Expression of Extracellular Matrix and Cell Adhesion Proteins in Vaginal Cells Derived From Premenopausal Women With Severe Pelvic Organ Prolapse

INTRODUCTION

Primary human vaginal cells derived from women with severe pelvic organ prolapse (POP-HVCs) demonstrate altered cellular characteristics as compared to cells derived from asymptomatic women (control-HVCs). Using computer-controllable Flexcell stretch unit, we examined whether POP-HVCs react differently to mechanical loading as compared to control-HVCs by the expression of extracellular matrix (ECM) components, cell-ECM adhesion proteins, and ECM degrading and maturating enzymes.

METHODS

Vaginal tissue biopsies from premenopausal patients with Pelvic Organ Prolapse Quantification System stage ≥3 (n = 8) and asymptomatic controls (n = 7) were collected during vaginal hysterectomy or repair. Human vaginal cells were isolated by enzymatic digestion, seeded on collagen (COLI)-coated plates, and stretched (24 hours, 25% elongation). Total RNA was extracted, and 84 genes were screened using Human ECM and Adhesion Molecules polymerase chain reaction array; selected genes were verified by quantitative reverse transcription-polymerase chain reaction. Stretch-conditioned media (SCM) were collected and analyzed by protein array, immunoblotting, and zymography.

RESULTS

In mechanically stretched control-HVCs, transcript levels of integrins (ITGA1, ITGA4, ITGAV, and ITGB1) and matrix metalloproteinases (MMPs) 2, 8, and 13 were downregulated (P < .05); in POP-HVCs, MMP1, MMP3, and MMP10, ADAMTS8 and 13, tissue inhibitor of metalloproteinases (TIMPs) 1 to 3, ITGA2, ITGA4, ITGA6, ITGB1, contactin (CNTN1), catenins (A1 and B1), and laminins (A3 and C1) were significantly upregulated, whereas COLs (1, 4, 5, 6, 11, and 12) and LOXL1 were downregulated. Human vaginal cells massively secrete MMPs and TIMPs proteins; MMP1, MMP8, MMP9 protein expression and MMP2 gelatinase activity were increased, whereas TIMP2 decreased in SCM from POP-HVCs compared to control-HVCs.

CONCLUSIONS

Primary human vaginal cells derived from women with severe pelvic organ prolapse and control-HVCs react differentially to in vitro mechanical stretch. Risk factors that induce stretch may alter ECM composition and cell-ECM interaction in pelvic floor tissue leading to the abatement of pelvic organ support and subsequent POP development.

Comparative Characterization of Vaginal Cells Derived From Premenopausal Women With and Without Severe Pelvic Organ Prolapse

BACKGROUND

This study tested a hypothesis that primary human vaginal cells derived from tissue of premenopausal women with severe pelvic organ prolapse (POP-HVCs) would display differential functional characteristics as compared to vaginal cells derived from asymptomatic women with normal pelvic floor support (control-HVCs).

METHODS

Vaginal tissue biopsies were collected from premenopausal patients with POP (n = 8) and asymptomatic controls (n = 7) during vaginal hysterectomy or repair. Primary vaginal cells were isolated by enzymatic digestion and characterized by immunocytochemistry. Cell attachment and proliferation on different matrices (collagen I, collagen II, collagen IV, fibronectin, laminin, tenascin, and vitronectin) were compared between POP-HVCs and control-HVCs. RNA was extracted, and the expression of 84 genes was screened using Human Extracellular Matrix and Adhesion Molecules RT(2) Profiler PCR array. The expression of selected genes was verified by quantitative reverse transcription-polymerase chain reaction.

RESULTS

(1) Control-HVCs attached to collagen IV more efficiently than POP-HVCs; (2) control-HVCs and POP-HVCs show a similar proliferation rate when plated on proNectin and collagen I; (3) when seeded on collagen I, resting POP-HVCs expressed significantly (P < .05) increased transcript levels of collagen VII, multiple matrix metalloproteinases (MMP3, MMP7, MMP10, MMP12, MMP13, and MMP14), integrins (ITGA1, ITGA4, ITGA6, ITGA8, ITGB1, ITGB2, and ITGB3), and cell adhesion molecules as compared to control-HVCs. Collagen XV and tissue inhibitors of MMPs (TIMP1 and TIMP2) as well as genes involved in the biogenesis and maturation of collagen and elastin fibers (LOX, LOXL1-LOXL3, BMP1, and ADAMTS2) were significantly downregulated in POP-HVCs versus control-HVCs (P < .05).

CONCLUSIONS

Resting primary POP-HVCs in vitro show altered cellular characteristics as compared to control-HVCs, which may influence their dynamic responses to external mechanical or hormonal stimuli.