Comparative analysis reveals distinct molecular heterogeneity in vaginal cells between recurrent and primary pelvic...

High recurrence rate in pelvic organ prolapse (POP) seriously increases treatment difficulty and elucidating the mechanisms is critical for developing targeted therapies. However, its underlying molecular mechanisms remain unclear. Using a single-cell RNA sequencing dataset, we analyzed vaginal fibroblasts, smooth muscle cells and macrophages in recurrent and primary POP. Comparative analysis of differentially expressed genes (DEGs) showed recurrent and primary POP shared fewer DEGs, while exhibiting more subtype-specific DEGs, confirming substantial molecular heterogeneity. Further analysis revealed that shared fibroblast DEGs in both POP subtypes were primarily enriched in collagen fibril organization, while recurrent POP showed uniquely upregulation of genes related to collagen metabolism and leukocyte migration. NKD2⁺ myofibroblasts were higher in recurrent POP compared to primary POP. In macrophages, shared upregulated DEGs in both groups were enriched in ECM remodeling and TGF-β signaling, highlighting conserved roles of macrophages-fibroblast interaction. Whereas, certain genes, such as fibrotic-related genes, were specifically upregulated in recurrent POP, implicating potential distinct fibrotic mechanisms in recurrence. Furthermore, the proportion of M2-like macrophages in recurrent POP was higher than primary POP. These findings reveal a potential shift toward pro-fibrotic and tissue-remodeling immune microenvironment in recurrent POP, providing novel insights into the cellular and molecular drivers of POP recurrence.