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.