Molecular Landscape of Pelvic Organ Prolapse Provides Insights into Disease Etiology

Pelvic organ prolapse (POP) represents a major health care burden in women, but its underlying pathophysiological mechanisms have not been elucidated. We first used a case-control design to perform an exome chip study in 526 women with POP and 960 control women to identify single nucleotide variants (SNVs) associated with the disease. We then integrated the functional interactions between the POP candidate proteins derived from the exome chip study and other POP candidate molecules into a molecular landscape. We found significant associations between POP and SNVs in 54 genes. The proteins encoded by 26 of these genes fit into the molecular landscape, together with 43 other POP candidate molecules. The POP landscape is located in and around epithelial cells and fibroblasts of the urogenital tract and harbors four interacting biological processes-epithelial-mesenchymal transition, immune response, modulation of the extracellular matrix, and fibroblast function-that are regulated by sex hormones and TGFB1. Our findings were corroborated by enrichment analyses of differential gene expression data from an independent POP cohort. Lastly, based on the landscape and using vaginal fibroblasts from women with POP, we predicted and showed that metformin alters gene expression in these fibroblasts in a beneficial direction. In conclusion, our integrated molecular landscape of POP provides insights into the biological processes underlying the disease and clues towards novel treatments.

Synthetic Extracellular Matrices as a Toolbox to Tune Stem Cell Secretome

The application of stem cell-derived secretome in regenerative therapies offers the key advantage that instead of the stem cells, only their effective paracrine compounds are in vivo delivered. Ideally, the secretome can be steered by the culture conditions of the stem cells. So far, most studies use stem cells cultured on stiff plastic substrates, not representative of their native 3D environment. In this study, cells are cultured inside synthetic polyisocyanide (PIC)-based hydrogels, which are minimal, tailorable, and highly reproducible biomimetic matrices. Secretome analysis of human adipose-derived stem cells (multiplex, ELISA) displays that matrix manipulation is a powerful tool to direct the secretome composition. As an example, cells in nonadherent PIC gels secrete increased levels of IL-10 and the conditioned media from 3D culture accelerate wound closure. In all, our PIC-based approach opens the door to dedicated matrix design to engineer the secretome for custom applications.

Genetic variants and expression changes in urgency urinary incontinence: A systematic review

Aim

To perform a systematic review summarizing the knowledge of genetic variants, gene, and protein expression changes in humans and animals associated with urgency urinary incontinence (UUI) and to provide an overview of the known molecular mechanisms related to UUI.

Methods

A systematic search was performed on March 2, 2020, in PubMed, Embase, Web of Science, and the Cochrane library. Retrieved studies were screened for eligibility. The risk of bias was assessed using the ROBINS‐I (human) and SYRCLE (animal) tool. Data were presented in a structured manner and in the case of greater than five studies on a homogeneous outcome, a meta‐analysis was performed.

Results

Altogether, a total of 10,785 records were screened of which 37 studies met the inclusion criteria. Notably, 24/37 studies scored medium‐high to high on risk of bias, affecting the value of the included studies. The analysis of 70 unique genes and proteins and three genome‐wide association studies showed that specific signal transduction pathways and inflammation are associated with UUI. A meta‐analysis on the predictive value of urinary nerve growth factor (NGF) levels showed that increased urinary NGF levels correlate with UUI.

Conclusion

The collective evidence showed the involvement of two molecular mechanisms (signal transduction and inflammation) and NGF in UUI, enhancing our understanding of the pathophysiology of UUI. Unfortunately, the risk of bias was medium‐high to high for most studies and the value of many observations remains unclear. Future studies should focus on elucidating how deficits in the two identified molecular mechanisms contribute to UUI and should avoid bias.

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.

Effectiveness of hormones in postmenopausal pelvic floor dysfunction-International Urogynecological Association research and development-committee opinion

Introduction and hypothesis

There is clear evidence of the presence of estradiol receptors (ERs) in the female lower urinary and genital tract. Furthermore, it is a fact that estrogen deficiency after menopause may cause atrophic changes of the urogenital tract as well as various urinary symptoms. Moreover, the effect of hormone replacement therapy (HRT) on urinary incontinence (UI) symptoms as well as pelvic organ prolapse (POP), anal incontinence (AI) and vulvovaginal symptoms (VVS) is still a matter of debate. This committee opinion paper summarizes the best evidence on influence of sex steroids as well as hormonal treatment (local and systemic) in postmenopausal women with pelvic floor disorders.

Methods

A working subcommittee from the International Urogynecology Association (IUGA) Research and Development Committee was formed. A thorough literature search was conducted and an opinion statement expressed. The literature regarding hormones and pelvic floor disorders was reviewed independently and summarized by the individual members of the sub-committee.

Results

The majority of studies reported that vaginal estrogen treatment when compared with placebo has more beneficial effects on symptoms and signs of vaginal atrophy including sensation of burning, dyspareunia and UI symptoms. Definitive evidence on local estrogen application and prolapse treatment or prevention is lacking. A statistically significant increase in risk of worsening of UI as well as development of de novo incontinence was observed with estrogen-only or combination systemic HRT.

Conclusions

In summary, local estrogen seems to be safe and effective in the treatment of VVS and can also improve urinary symptoms in postmenopausal patients with UI, but most of these recommendations correspond to evidence level 2C. The evidence in POP is still scarce but not in favor of benefit. Finally, the duration of local estrogen treatment (LET), optimal dosage, long-term effects and cost-effectiveness compared with current practice are still unknown.

Regenerative medicine as a therapeutic option for fecal incontinence: a systematic review of preclinical and clinical studies

BACKGROUND

Fecal incontinence is the uncontrollable loss of stool and has a prevalence of around 7-15%. This condition has serious implications for patients' quality of life. Current treatment options show unsatisfactory results. A novel treatment option is therefore needed.

OBJECTIVE

This systematic review aims to perform a quality assessment and to give a critical overview of the current research available on regenerative medicine as a treatment for fecal incontinence.

STUDY DESIGN

A systematic search strategy was applied in PubMed, Cochrane Library, EMBASE, MEDLINE, Web of Science, and Cinahl from inception until March of 2018. Studies were found relevant when the animals or patients in the studied group had objectively determined or induced fecal incontinence, and the intervention must have used any kind of cells, stem cells, or biocompatible material, with or without the use of trophic factors. Studies were screened on title and consecutively on abstract for relevance by 2 independent investigators. The risk of bias of preclinical studies was assessed using the SYstematic Review Centre for Laboratory animal Experimentation risk of bias tool for animal studies, and for clinical studies the Cochrane risk of bias tool for randomized trials was used.

RESULTS

In all, 34 preclinical studies and 5 clinical studies were included. Animal species, type of anal sphincter injury, intervention, and outcome parameters were heterogenous. Therefore, a meta-analysis could not be performed. The overall risk of bias of the included studies was high.

CONCLUSION

The efficacy of regenerative medicine to treat fecal incontinence could not be determined due to the high risk of bias and heterogenicity of the available preclinical and clinical studies. The findings of this systematic review may result in improved study design of future studies, which could help the translation of regenerative medicine to the clinic as an alternative to current treatments for fecal incontinence.

Prevention of pelvic floor disorders: international urogynecological association research and development committee opinion

INTRODUCTION AND HYPOTHESIS

Pelvic floor disorders (PFD), including urinary incontinence, anal incontinence, and pelvic organ prolapse, are common and have a negative effect on the quality of life of women. Treatment is associated with morbidity and may not be totally satisfactory. Prevention of PFDs, when possible, should be a primary goal. The purpose of this paper is to summarise the current literature and give an evidence-based review of the prevention of PFDs METHODS: A working subcommittee from the International Urogynecological Association (IUGA) Research and Development (R&D) Committee was formed. An initial document addressing the prevention of PFDs was drafted, based on a review of the English-language literature. After evaluation by the entire IUGA R&D Committee, revisions were made. The final document represents the IUGA R&D Committee Opinion on the prevention of PFDs.

RESULTS

This R&D Committee Opinion reviews the literature on the prevention of PFDs and summarises the findings with evidence-based recommendations.

CONCLUSIONS

Pelvic floor disorders have a long latency, and may go through periods of remission, thus making causality difficult to confirm. Nevertheless, prevention strategies targeting modifiable risk factors should be incorporated into clinical practice before the absence of symptomatology.

Functional characteristics of vaginal fibroblastic cells from premenopausal women with pelvic organ prolapse

Pelvic organ prolapse (POP) remains a great therapeutic challenge with no optimal treatment available. Tissue maintenance and remodelling are performed by fibroblasts, therefore altered cellular functionality may influence tissue quality. In this study, we evaluated functional characteristics of fibroblastic cells from tissues involved in POP. To rule out normal ageing tissue degeneration, biopsies from 18 premenopausal women were collected from the precervical region (non-POP site) after hysterectomy of 8 healthy and 10 POP cystocele cases (POP-Q stage ≥ II). Extra tissues from the prolapsed sites were taken in the POP cases to distinguish between intrinsic and acquired cellular defects. Twenty-eight primary fibroblastic cultures were studied in vitro. A contractility assay was used to test fibroblast-mediated collagen contraction. Cellular mechanoresponses on collagen-coated or uncoated substrates were evaluated by measuring matrix remodelling factors at protein or gene expression levels. No differences were found between fibroblasts from the controls and the non-POP site of the case group. Fibroblastic cells from the prolapsed site showed delayed fibroblast-mediated collagen contraction and lower production of matrix metalloproteinase-2 (MMP-2) on collagen-coated plates. On uncoated surfaces the gene MMP-2 and its tissue inhibitor of metalloproteinases-2 were up-regulated in POP site fibroblastic cells. In conclusion, fibroblastic cells derived from prolapsed tissues of patients with cystocele, display altered in vitro functional characteristics depending on the surface substrate and compared with non-prolapsed site. This implies an acquired rather than an intrinsic defect for most patients with cystocele, and should be taken into account when trying to improve treatments for POP.

Changes in tissue composition of the vaginal wall of premenopausal women with prolapse

OBJECTIVE

The objective of this study was to compare histological and biochemical features of the (normal) precervical anterior vaginal wall and the prolapsed anterior vaginal wall of women with pelvic organ prolapse (POP). These data were compared to tissue of the precervical anterior vaginal wall of age-matched controls without POP to identify possible intrinsic and acquired effects.

STUDY DESIGN

Biopsies were collected from the apex of the anterior vaginal cuff after hysterectomy from a control group of 13 premenopausal women undergoing hysterectomy for benign gynecological diseases, and a case group of 13 premenopausal women undergoing prolapse surgery (cystocele POP-Quantification stage ≥2). In women with POP an additional full-thickness vaginal wall sample was taken from the POP site during anterior colporrhaphy. Histomorphometric and biochemical analysis were performed for different components of the extracellular matrix.

RESULTS

There were no differences between case and control group in the precervical vaginal wall tissue with respect to the different components of the extracellular matrix and the biochemical parameters. However, there was a tendency toward a higher amount of collagen III and elastin, and a significant increase of smooth muscle cells and pyridinoline collagen cross-links in the POP site compared to the non-POP site of the same POP patient.

CONCLUSION

Our findings suggest that the changes seen in connective tissue in the anterior vaginal wall of women with POP are the effect, rather than the cause, of POP.

Fibroblasts from women with pelvic organ prolapse show differential mechanoresponses depending on surface substrates

INTRODUCTION AND HYPOTHESIS

Little is known about dynamic cell-matrix interactions in the context of pathophysiology and treatments for pelvic organ prolapse (POP). This study sought to identify differences between fibroblasts from women with varying degrees of prolapse in reaction to mechanical stimuli and matrix substrates in vitro.

METHODS

Fibroblasts from the vaginal wall of three patients with POP Quantification (POP-Q) system stages 0, II, and IV were stretched on artificial polymer substrates either coated or not coated with collagen I. Changes in morphology and anabolic/catabolic compounds that affect matrix remodelling were evaluated at protein- and gene-expression levels. Statistical analysis was performed using one-way analysis of variance (ANOVA), followed by Tukey-Kramer's post hoc test.

RESULTS

POP fibroblasts show delayed cell alignment and lower responses to extracellular matrix remodelling factors at both enzymatic- and gene-expression levels compared with healthy fibroblasts.

CONCLUSION

POP fibroblasts, when compared with healthy cells, show differential mechanoresponses on two artificial polymer substrates. This should be taken into account when designing or improving implants for treating POP.