Transcriptomic analysis reveals "adipogenesis" in the uterosacral ligaments of postmenopausal women with recurrent pelvic organ prolapse.

OBJECTIVES: Pelvic organ prolapse (POP) is a common condition in postmenopausal women, with an increasing prevalence due to aging. Some women experience POP recurrence after surgical treatment, significantly affecting their physical and mental health. The uterosacral ligament is a critical pelvic support structure. This study aims to investigate the molecular pathological changes in the uterosacral ligament of postmenopausal women with recurrent POP using transcriptomic analysis. METHODS: Transcriptomic data of uterosacral ligament tissues were obtained from the public dataset GSE28660, which includes samples from 4 postmenopausal women with recurrent POP, 4 with primary POP, and 4 without POP. Differentially expressed genes (DEGs) were identified between recurrent POP and both primary and non-POP groups. Further analysis included intersection analysis of DEGs, gene ontology enrichment, protein-protein interaction (PPI) network construction, gene set enrichment analysis (GSEA), single-sample GSEA, and xCell immune cell infiltration analysis to explore molecular pathological changes in recurrent POP. Additionally, histological and molecular differences in the uterosacral ligament were compared between simulated vaginal delivery (SVD) rat models with and without ovariectomy. RESULTS: Compared with primary POP and non-POP groups, recurrent POP exhibited activation of adipogenesis and inflammation-related pathways, while pathways related to muscle proliferation and contraction were downregulated in the uterosacral ligament. Nine key DEGs (ADIPOQ, FABP4, IL-6, LIPE, LPL, PCK1, PLIN1, PPARG, and CD36) were identified, with most enriched in the peroxisome proliferator-activated receptor (PPAR) signaling pathway. These genes were significantly correlated with lipid accumulation, monocyte infiltration, and neutrophil infiltration in the uterosacral ligament. Urodynamic testing revealed that the bladder leak point pressure was significantly higher in ovariectomized SVD rats, both of which had higher values than the sham group. Masson staining showed pronounced adipogenesis in the uterosacral ligament of ovariectomized SVD rats, along with reduced collagen and muscle fibers compared to the sham and non-ovariectomized SVD groups. Furthermore, real-time RT-PCR confirmed significantly elevated expression of key DEGs, including ADIPOQ, IL-6, PCK1, and PLIN1, in the uterosacral ligaments of ovariectomized SVD rats. CONCLUSIONS: Adipogenesis and inflammation in the uterosacral ligament may contribute to its reduced supportive function, potentially leading to recurrence POP in postmenopausal women.