Clinical meaning
Pelvic organ prolapse (POP) results from failure of the pelvic floor support system - an integrated complex of muscles (levator ani group: pubococcygeus, puborectalis, iliococcygeus), endopelvic fascia (pubocervical fascia anteriorly, rectovaginal fascia posteriorly), and ligaments (cardinal and uterosacral ligaments). Uterine prolapse specifically involves descent of the uterus and cervix through the vaginal canal due to failure of the cardinal-uterosacral ligament complex. At the molecular level, POP is characterized by alterations in the extracellular matrix (ECM) of pelvic connective tissues. Type I and III collagen are the primary structural proteins providing tensile strength to pelvic fascia and ligaments. In women with POP, there is decreased total collagen content with an increased ratio of type III collagen (thinner, less rigid) to type I collagen (thick, high tensile strength). This shift weakens the tissue's ability to resist gravitational and intra-abdominal forces. Matrix metalloproteinases (MMPs) - particularly MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), and MMP-9 (gelatinase B) - are significantly upregulated in the vaginal wall and uterosacral ligaments of women with POP. These zinc-dependent endopeptidases degrade collagen, elastin, and other ECM components. Simultaneously, tissue...