Collagen XVIII and LOXL-4 polymorphisms in women with and without advanced pelvic organ prolapse

Mini-review: Modern Concept of Pelvic Organ Prolapse

Symptomatic pelvic organ prolapse (POP) has been increasing in recent years for both developed and developing countries. By 2050, as the adult population grows, the number of women with symptomatic POP will increase by 46%. Due to the increasing number of complications after surgery among women with POP, the current understanding of treatment has become extremely important for researchers and practitioners. There are many novel conservative and surgical treatment approaches under investigation. However, some primary surgical treatments show an approximate 30–50% risk of repeated pelvic floor reconstruction. Therefore, the review aims to summarize several conservative treatment options and identify critical areas of need for future research.

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.

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

INTRODUCTION AND HYPOTHESIS

Family and twin studies demonstrate that pelvic organ prolapse (POP) is heritable, but the genetic etiology is poorly understood. This review aimed to identify genetic loci and specific polymorphisms associated with POP, while assessing the strength, consistency, and risk of bias among reported associations.

METHODS

Updating an earlier systematic review, PubMed and HuGE Navigator as well as relevant conference abstracts were searched using genetic and phenotype keywords from 2015 to 2020. Screening and data extraction were performed in duplicate. Fixed and random effects meta-analyses were conducted using co-dominant models of inheritance. We assessed credibility of pooled associations using interim Venice criteria.

RESULTS

We screened 504 new abstracts and included 46 published and 7 unpublished studies. In pooled analyses we found significant associations for four polymorphisms: rs2228480 at the ESR1 gene (OR 0.67 95% CI 0.46-0.98, I² = 0.0%, Venice rating BAB), rs12589592 at the FBLN5 gene (OR 1.46 95% CI 1.11-1.82, I² = 36.3%, Venice rating BBB), rs484389 in the PGR gene (OR 0.61 95% CI 0.39-0.96, I² = 32.4%, Venice rating CBB), and rs1800012 at the COL1A1 gene (OR 0.80 95% CI 0.66-0.96, I² = 0.0%, Venice rating BAB). Further credible novel variants have also been recently identified in genome-wide association studies.

CONCLUSION

The genetic contributions to POP remain poorly understood. Several biologically plausible variants have been identified, but much work is required to establish the role of these genes in the pathogenesis of POP or to establish a role for genetic testing in clinical practice.

Collagen type 1A1, type 3A1, and LOXL1/4 polymorphisms as risk factors of pelvic organ prolapse

Objective

Collagen and elastin are the main components of the female pelvic tissue. We investigated whether single nucleotide polymorphisms (SNPs) of collagen type 1 alpha 1 (COL1A1), collagen type 3 alpha 1 (COL3A1), and lysyl oxidase-like (LOXL) 1 and 4 were associated with the onset of pelvic organ prolapse (POP) in Japanese women. Fifty-two women with POP and 28 women without POP were included. SNPs were identified using the TaqMan® SNP genotyping assay.

Results

Age, parity, and lower urinary tract symptoms were significantly higher in the POP group than in the control group. The prevalence of genotypes with rs2862296 polymorphism of LOXL4, an enzyme essential for extracellular matrix remodeling, was different between the POP (26.9% for GG, 51.9% for AG) and control groups (14.8% for GG, 33.3% for AG). However, polymorphisms of COL1A1, COL3A1, and LOXL1 were not related to the onset of POP. In the multivariate logistic regression analysis, age was significantly associated with the occurrence of POP. In the univariate analysis, LOXL4 polymorphism was associated with the onset of POP in Japanese women. The knowledge of acquired risk factors and polymorphisms in the genomic background of patients with POP may help prevent POP via early conservative interventions.

Genetic polymorphisms in collagen-related genes are associated with pelvic organ prolapse

OBJECTIVE

Pelvic organ prolapse (POP) is a common health issue that has a profound negative influence on women's quality of life. Genetic susceptibility to POP has been increasingly investigated. In this study, we assessed the single-nucleotide polymorphisms (SNPs) of six collagen-related genes (COL14A1, COL5A1, COL4A2, COL3A1, COL1A1, and COL18A1) and the genetic association with POP in Chinese women.

METHODS

We performed a candidate gene association study of case women (n = 48) with stage III and IV prolapse and control women (n = 48) without prolapse. A target region sequencing approach was used to identify the SNPs in collagen-related genes. The association between SNPs and POP was examined by Fisher exact tests for unadjusted model and logistic regression analysis adjusted for delivery and pregnancy.

RESULTS

There was a significant association between COL14A1 SNPs (rs4870723, rs2305600, and rs2305598; P = 0.013, 0.019, and 0.028, respectively), a COL5A1 SNP (rs3827852; P = 0.016), and COL4A2 SNPs (rs76425569, rs388222, and rs2281968; P = 0.049 for the three, and rs445348, P = 0.040) and POP, respectively. Although there was no significant association between the COL3A1 SNP and POP, there was a trend toward significance for COL14A1 SNP (rs2305603), COL4A2 SNP (rs74941798), two COL1A1 SNPs (rs2586488 and rs2249492) and three COL18A1 SNPs (rs1050351, rs56335679, and rs55690336), and POP.

CONCLUSION

We are the first to evaluate the relationship between COL14A1, COL5A1, and COL4A2 polymorphisms and POP, besides COL3A1, COL1A1, and COL18A1, which have been reported previously. We found several candidate SNPs that were significantly associated with prolapse in Chinese women. Our results provide new evidence for further investigation of the involvement of these potential genes in the etiology of POP.