Systematic review and meta-analysis of genetic association studies of pelvic organ prolapse

The rs2018736 fibulin-5 polymorphism as a determinant for pelvic organ prolapse: a case-control study

OBJECTIVE

Fibulin-5 is a connective tissue component and may play a role in pelvic organ prolapse (POP) pathogenesis. This study aimed to verify the association of the rs2018736 polymorphism of the fibulin-5 gene with POP in postmenopausal Brazilian women, and to determine the risk factors for POP.

METHOD

This observational, cross-sectional, case-control study assessed postmenopausal women with advanced POP (stages III and IV) and control women (stages 0 and I) by examination and peripheral blood sample collection. DNA sequences were analyzed by real-time reverse-transcriptase polymerase chain reaction. A logistic regression model was used with p < 0.05 for significance.

RESULTS

A total of 565 participants were evaluated (325 POP and 240 control). The homozygous C allele of rs2018736 (CC) was protective against POP (odds ratio [OR] 0.49, 95% confidence interval [CI] 0.26-0.91). Age (OR 1.09, 95% CI 1.05-1.13), number of pregnancies (OR 1.14, 95% CI 1.01-1.28), vaginal delivery (OR 5.32, 95% CI 2.58-11.01), forceps delivery (OR 3.34, 95% CI 1.72-6.47), weight of newborn (OR 1.0007, 95% CI 1.0002-1.0011), family history of POP (OR 2.35, 95% CI 1.24-4.44), hypertension (OR 1.74, 95% CI 1.01-3.00) and diabetes (OR 2.19, 95% CI 1.07-4.48)] were independent predictors for POP; cesarean (OR 0.02, 95% CI 0.005-0.09) was protective.

CONCLUSION

The rs2018736-CC genotype of the fibulin-5 gene has a protective role against POP.

Psychometric evaluation and cross-cultural adaptation of the Australian Pelvic Floor Questionnaire (APFQ-IR) in Iranian reproductive age women

Pelvic floor disorders (PFDs), as a silent alert, is one of the pervasive debilitating health concerns among women all over the world, such that in developed countries, one in four women, suffers from PFDs. Validity and reliability of the Australian Pelvic Floor Questionnaire (APFQ) has not been determined in Iran, so to determine APFQ's psychometric characteristics, we decided to conduct this study on women of reproductive age in Tabriz city, Iran. This methodological cross-sectional study was intended to determine the psychometric properties of the Persian version of the APFQ-IR in 5 steps including "translation process, content validity, face validity, construct validity (exploratory and confirmatory factor analyses and examination of ceiling and floor effects) and reliability" on 400 reproductive age women referring to health centers in Tabriz city, Iran, with cluster random sampling method in the period between May 2022 to September 2022. The translation process was done based on two approaches, Dual panel, and Beaton et al.'s five steps. Then, in order to evaluate content validity, face validity, and construct validity, 10 instrument and PFDs experts, 10 women from the target group investigated the instrument's items, and 400 eligible women completed the instrument. Finally, to determine the reliability, two internal consistency methods, (Cronbach's alpha and McDonald's omega) and test-retest method (ICC) were used. In the present study, content validity assessment of APFQ-IR, showed a good level of validity (CVR = 0.96, CVI = 0.94). To assess construct validity, exploratory factor analysis results on 36 items, led to the identification of 4 factors including bladder function, bowel function, prolapse symptom and sexual function, which explained 45.53% of the cumulative variance and indicated the sufficiency of the sample size (Kaiser-Meyer-Olkin = 0.750). Implementing confirmatory factor analysis, (RMSEA = 0.08, SRMR = 0.08, TLI = 0.90, CFI = 0.93, χ2/df = 3.52) confirmed the model fit indices. Finally the internal consistency and reliability was high for the entire instrument (Cronbach's alpha = 0.85; McDonald's omega (95% CI) = 0.85 (0.83-0.87) and Intraclass Correlation Coefficient (95% CI) = 0.88 (0.74-0.94)). The Persian version of the APFQ-IR, has a good validity and reliability and has acceptable psychometric properties, thus can be used both for research purposes and for clinical evaluation of pelvic floor disorders symptoms in health centers.

Association between the rs1036819 polymorphism of the ZFAT gene and pelvic organ prolapse: a case-control study

INTRODUCTION AND HYPOTHESIS

The identification of risk factors for pelvic organ prolapse (POP) would contribute to planning prevention strategies. This study tests the hypothesis that the rs1036819 polymorphism in the ZFAT gene is associated with POP and investigates other risk factors for prolapse development.

METHODS

A case-control study was carried out including 826 postmenopausal women divided into POP cases (stages III and IV) and controls (stages 0 and I), assessed by anamnesis, examination, and peripheral blood samples. DNA was extracted from blood and genotyped by real-time RT-PCR. We used logistic regression models for the association analyses of variables, with p < 0.05 for significance.

RESULTS

Five hundred and sixty-eight women were evaluated (315 POP and 253 controls). The minor allele C was found in 19.3% of our sample and the genotype frequencies of AA, AC, and CC were similar in both groups. Age (OR 1.09, 95% CI 1.06-1.13), number of pregnancies (OR 1.23, 95% CI 1.08-1.41), history of one vaginal delivery (OR 3.39, 95% CI 1.38-8.33) or two or more (OR 2.51, 95% CI 1.04-6.07), weight of the largest newborn (OR 1.0001, 95% CI 1-1.001), and family history of POP (OR 2.27, 95% CI 1.24-4.13) were independent risk factors for POP, whereas one cesarean section (OR 0.48, 95% CI 0.27-0.88) or two or more (OR 0.14, 95% CI 0.05-0.38) were protective.

CONCLUSIONS

No association was detected between the rs1036819 polymorphism of the ZFAT gene and advanced POP. Age, number of pregnancies, at least one vaginal delivery, weight of the newborn, and POP family history were independent risk factors for POP.

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.

Identification of potential molecular mechanisms and therapeutic targets for recurrent pelvic organ prolapse

Background

The pathogenesis of recurrent pelvic organ prolapse (POP) is currently unclear. Therefore, developing targeted preventive measures is difficult. This study identified potential key pathways, crucial genes, comorbidities, and therapeutic targets associated with the occurrence and development of recurrent POP.

Methods

The original microarray data GSE28660, GSE53868, and GSE12852 were downloaded from the GEO database. Identification and validation of differentially expressed genes (DEGs) and hub genes associated with recurrent POP were performed using R software and cytoHubba of Cytoscape. Protein-protein interaction (PPI) networks were constructed using the STRING tool and visualized using Cytoscape. Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) enrichment analyses were effectively performed using DAVID platforms. In addition, the NetworkAnalyst platform was used to explore and visualize the miRNA-hub gene network, TF-hub gene network, hub gene-disease network, and hub gene-drug/chemical network.

Results

A total of 110 DEGs and 6 hub genes (ADIPOQ, IL6, PPARG, CEBPA, LPL, and LIPE) were identified in this study. These genes were primarily enriched in the PPAR, AMPK, and adipocytokine, non-alcoholic fatty liver disease, and signaling pathways related to glycerol metabolism. Moreover, 96 miRNAs and 97 TFs were identified to as being associated with recurrent POP. These genes were closely linked to adipocyte metabolism and distribution, energy metabolism, and the longevity regulatory pathway. In addition, 192 diseases or chronic complications were potentially related to the recurrence of POP, including diabetes, hypertension, obesity, inflammatory diseases, and chronic obstructive pulmonary disease. Furthermore, 954 drugs or compounds were shown to have therapeutic potential for recurrent POP, and the most critical target drugs were dexamethasone, bisphenol A, efavirenz, 1-methyl-3-isobutylxanthine, and estradiol.

Conclusions

The results of this study revealed that ADIPOQ, IL6, PPARG, CEBPA, LPL, and LIPE as potential hub genes associated with recurrent POP, and these hub genes may aid in the understanding of the mechanism underlying POP recurrence and the development of potential molecular drugs.

Translation and measurement properties of the pelvic floor distress inventory-short form (PFDI-20) in Iranian reproductive age women

BACKGROUND

Every year, millions of women worldwide suffer in silence from pelvic floor disorders (PFDs) as an annoying health problem. Despite the high prevalence rate and negative effects of PFDs on the quality of life, the validity and reliability of pelvic floor distress inventory-short form (PFDI-20) has not been confirmed for Iranian women of reproductive age. Hence, this study aimed to determine measurement properties of PFDI-20 among women of reproductive age in Tabriz, Iran.

METHODS

The current study was cross-sectional research that selected 400 women of reproductive age referring to health centers in Tabriz City, by using cluster random sampling from May 2022 to September 2022. Measurement properties of the Persian version of PFDI-20 were determined and evaluated through five steps, including content and face validity within two quantitative and qualitative parts, structural validity by using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), and reliability testing through internal consistency, test-retest reliability, and measurement error. Moreover, ceiling and floor effects were investigated.

RESULTS

In this research, CVI (content validity index) and CVR (content validity ratio) of PFDI-20 equaled 0.94 and 0.97, respectively. In addition, the EFA process was applied to 20 items and derived the structure of three factors, which explained 58.15% of the total variance. In CFA phase, values of fit indicators (RMSEA = 0.07, SRMR = 0.07, TLI = 0.97, CFI = 0.99, x2/df = 3.19) confirmed the model validity. To determine reliability, Cronbach's alpha = 0.84; McDonald's omega (95% CI) = 0.84 (0.82 to 0.87) and Intraclass Correlation Coefficient (95% CI) = 0.98 (0.97 to 0.99) were obtained. Also, the SEM was 2.64, and the SDC indicating the smallest individual change was 8.91. Regarding the inventory feasibility, the ceiling effect was not observed in total value and subscales, while the floor effect in the total score of PFDI-20 equaled 24.0. The latter rate equaled 45.8, 38.3, and 50.8 for subscales POPDI-6, CRADI-8, and UDI-6, respectively.

CONCLUSIONS

Persian version of PFDI-20 is a valid and reliable scale used to evaluate PFDs in Iranian women of reproductive age. Healthcare professionals can use this scale to screen PFDs, and researchers can consider it a reliable tool for their studies.

Interactions between genetic variants and environmental risk factors are associated with the severity of pelvic organ prolapse

OBJECTIVE

Both environmental and genetic risk factors contribute to pelvic organ prolapse (POP). No genome-wide study has investigated the gene-environment (G × E) interactions. In this study, we aim to identify single nucleotide polymorphisms (SNPs) that may interact with the potential environmental factors, maximum birth weight, and age in Chinese women.

METHODS

We recruited 576 women for phase 1 and 264 women for phase 2 with stages III and IV prolapse from six geographic regions of China. Genomic DNAs from blood samples were genotyped using Affymetrix Axiom Genome-Wide CHB1 Array of 640,674 SNPs for phase 1 and Illumina Infinium Asian Screening Array of 743,722 SNPs for phase 2. Meta-analysis was used to combine the two results. Interactions of genetic variants with maximum birth weight and age on POP severity were identified.

RESULTS

In phase 1, 502,283 SNPs in 523 women passed quality control and 450 women had complete POP-quantification measurements. In phase 2, 463,351 SNPs in 257 women passed quality control with complete POP-quantification measurements. Three SNPs rs76662748 ( WDR59 , Pmeta = 2.146 × 10 -8 ), rs149541061 ( 3p26.1 , Pmeta = 9.273 × 10 -9 ), and rs34503674 ( DOCK9 , Pmeta = 1.778 × 10 -9 ) respectively interacted with maximum birth weight, and two SNPs rs74065743 ( LINC01343 , Pmeta = 4.386 × 10 -8 ) and rs322376 ( NEURL1B - DUSP1 , Pmeta = 2.263 × 10 -8 ), respectively, interacted with age. The magnitude of disease severity associated with maximum birth weight and age differed according to genetic variants.

CONCLUSIONS

This study provided preliminary evidence that interactions between genetic variants and environmental risk factors are associated with POP severity, suggesting the potential use of combining epidemiologic exposure data with selected genotyping for risk assessment and patient stratification.

Nonoperative Management of Pelvic Organ Prolapse

Pelvic organ prolapse (POP) is defined as the descent of one or more of the anterior, posterior, or apical vagina. It is a common condition, with up to 50% of women having prolapse on examination in their lifetimes. This article provides an overview of the evaluation and discussion of nonoperative management of POP for the obstetrician-gynecologist (ob-gyn), with consideration of recommendations from the American College of Obstetricians and Gynecologists, the American Urogynecologic Society, and the International Urogynecological Association. The initial evaluation of POP requires a history documenting whether the patient is experiencing symptoms and what they are, and discovery of which symptoms they believe are attributable to prolapse. Examination determines the vaginal compartment(s) and to what degree prolapse exists. In general, only patients who have symptomatic prolapse or medical indication should be offered treatment. Although surgical options exist, all patients who are symptomatic and desire treatment should be offered nonsurgical treatment first, including pelvic floor physical therapy or a pessary trial. Appropriateness, expectations, complications, and counseling points are reviewed. Educational opportunities between the patient and the ob-gyn include disentangling common beliefs that the bladder is dropping or that concomitant urinary or bowel symptoms are necessarily caused by prolapse. Improving patient education can lead to a better understanding of their condition and better alignment of treatment goals and expectations.

The plasticity of biocompatibility

Biocompatibility concerns the phenomena that occur within the interactions between biomaterials and human patients, which ultimately control the performance of many facets of medical technology. It involves aspects of materials science, many different forms of engineering and nanotechnology, chemistry, biophysics, molecular and cellular biology, immunology, pathology and a myriad of clinical applications. It is not surprising that an overarching framework of mechanisms of biocompatibility has been difficult to elucidate and validate. This essay discusses one fundamental reason for this; we have tended to consider biocompatibility pathways as essentially linear sequences of events which follow well-understood processes of materials science and biology. The reality, however, is that the pathways may involve a great deal of plasticity, in which many additional idiosyncratic factors, including those of genetic, epigenetic and viral origin, exert influence, as do complex mechanical, physical and pharmacological variables. Plasticity is an inherent core feature of the performance of synthetic materials; here we follow the more recent biological applications of plasticity concepts into the sphere of biocompatibility pathways. A straightforward linear pathway may result in successful outcomes for many patients; we may describe this in terms of classic biocompatibility pathways. In other situations, which usually command much more attention because of their unsuccessful outcomes, these plasticity-driven processes follow alternative biocompatibility pathways; often, the variability in outcomes with identical technologies is due to biological plasticity rather than material or device deficiency.

The difference in collagen type-1 expression in women with and without pelvic organ prolapse: a systematic review and meta-analysis

INTRODUCTION AND HYPOTHESIS

This study was aimed at identifying the difference in collagen type-1 expression in women with and without pelvic organ prolapse (POP).

METHODS

A systematic review and meta-analysis was carried out women with and without pelvic organ prolapse. This meta-analysis was conducted on research articles describing the evaluation of collagen type-1 expression between patients with and without POP. The articles were obtained from PubMed, EBSCO, and ProQuest, and were published between January 2000 and June 2021. Pooled mean difference (MD) and pooled odds ratio (OR) were calculated using fixed effect models. Review Manager (RevMan 5.4) was used to analyze the data. The main outcome measures were pooled MD and pooled OR of collagen type-1 expression in patients with and without POP.

RESULTS

A total of seven case-control studies were included in the meta-analysis using the effect size of the MD and two case-control studies were included in the meta-analysis using the effect size of the OR. A total of 247 POP cases and 132 non-POP cases were identified from the studies. Our study indicated that patients with POP had a lower level of collagen type-1 expression than non-POP patients (MD = -6.77; 95% CI: -8.37, -5.17, p < 0.00001). Patients with low expression of collagen type-1 in pelvic support tissue are at a more than 3 times higher risk of suffering from pelvic organ prolapse (OR = 3.23, 95% CI: 1.52 to 6.87, p = 0.002).

CONCLUSION

The results of this study showed that patients with pelvic organ prolapse have lower expression of collagen type-1 than nonpelvic organ prolapse patients.

International Urogynecological Consultation (IUC): pathophysiology of pelvic organ prolapse (POP)

INTRODUCTION AND HYPOTHESIS

This manuscript is the International Urogynecology Consultation (IUC) on pelvic organ prolapse (POP) chapter one, committee three, on the Pathophysiology of Pelvic Organ Prolapse assessing genetics, pregnancy, labor and delivery, age and menopause and animal models.

MATERIALS AND METHODS

An international group of urogynecologists and basic scientists performed comprehensive literature searches using pre-specified terms in selected biomedical databases to summarize the current knowledge on the pathophysiology of the development of POP, exploring specifically factors including (1) genetics, (2) pregnancy, labor and delivery, (3) age and menopause and (4) non-genetic animal models. This manuscript represents the summary of three systematic reviews with meta-analyses and one narrative review, to which a basic scientific comment on the current understanding of pathophysiologic mechanisms was added.

RESULTS

The original searches revealed over 15,000 manuscripts and abstracts which were screened, resulting in 202 manuscripts that were ultimately used. In the area of genetics the DNA polymorphisms rs2228480 at the ESR1 gene, rs12589592 at the FBLN5 gene, rs1036819 at the PGR gene and rs1800215 at the COL1A1 gene are significantly associated to POP. In the area of pregnancy, labor and delivery, the analysis confirmed a strong etiologic link between vaginal birth and symptoms of POP, with the first vaginal delivery (OR: 2.65; 95% CI: 1.81-3.88) and forceps delivery (OR: 2.51; 95% CI: 1.24-3.83) being the main determinants. Regarding age and menopause, only age was identified as a risk factor (OR : 1.102; 95% CI: 1.02-1.19) but current data do not identify postmenopausal status as being statistically associated with POP. In several animal models, there are measurable effects of pregnancy, delivery and iatrogenic menopause on the structure/function of vaginal support components, though not on the development of POP.

CONCLUSIONS

Genetics, vaginal birth and age all have a strong etiologic link to the development of POP, to which other factors may add or protect against the risk.

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.

Mouse Knockout Models for Pelvic Organ Prolapse: a Systematic Review

INTRODUCTION AND HYPOTHESIS

Mouse knockout (KO) models of pelvic organ prolapse (POP) have contributed mechanistic evidence for the role of connective tissue defects, specifically impaired elastic matrix remodeling. Our objective was to summarize what mouse KO models for POP are available and what have we learned from these mouse models about the pathophysiological mechanisms of POP development.

METHODS

We conducted a systematic review and reported narrative findings according to PRISMA guidelines. Two independent reviewers searched PubMed, Scopus and Embase for relevant manuscripts and conference abstracts for the time frame of January 1, 2000, to March 31, 2021. Conference abstracts were limited to the past 5 years.

RESULTS

The search strategy resulted in 294 total titles. We ultimately included 25 articles and an additional 11 conference abstracts. Five KO models have been studied: Loxl1, Fbln5, Fbln3, Hoxa11 and Upii-sv40t. Loxl1 and Fbln5 KO models have provided the most reliable and predictable POP phenotype. Loxl1 KO mice develop POP primarily from failure to heal after giving birth, whereas Fbln5 KO mice develop POP with aging. These mouse KO models have been used for a wide variety of investigations including genetic pathways involved in development of POP, biomechanical properties of the pelvic floor, elastic fiber deposition, POP therapies and the pathophysiology associated with mesh complications.

CONCLUSIONS

Mouse KO models have proved to be a valuable tool in the study of specific genes and their role in the development and progression of POP. They may be useful to study POP treatments and POP complications.