BACKGROUND: Fibrosis of the connective tissue in the vaginal wall predominates in pelvic organ prolapse (POP), which is characterized by excessive fibroblast-to-myofibroblast differentiation and abnormal deposition of the extracellular matrix (ECM). Our study aimed to investigate the effect of ECM stiffness on vaginal fibroblasts and to explore the role of methyltransferase 3 (METTL3) in the development of POP. METHODS: Polyacrylamide hydrogels were applied to create an ECM microenvironment with variable stiffness to evaluate the effects of ECM stiffness on the proliferation, differentiation, and expression of ECM components in vaginal fibroblasts. METTL3 small interfering RNA and an overexpression vector were transfected into vaginal fibroblasts to evaluate the effects of METTL3 silencing and overexpression on matrix stiffness-induced vaginal fibroblast-to-myofibroblast differentiation and abnormal modulation of the ECM. Both procedures were detected by 5-ethynyl-2'-deoxyuridine (EdU) staining, Western blotting (WB), quantitative real-time polymerase chain reaction (RT-qPCR), and immunofluorescence (IF). RESULTS: Vaginal fibroblasts from POP patients exhibited increased proliferation ability, increased expression of α-smooth muscle actin (α-SMA), decreased expression of collagen I/III, and significantly decreased expression of tissue inhibitors of matrix metalloproteinases (TIMPs) in the stiff matrix ( P <0.05). Compared with those from non-POP patients, vaginal wall tissues from POP patients demonstrated a significant increase in METTL3 content ( P <0.05). However, silencing METTL3 expression in vaginal fibroblasts with high ECM stiffness resulted in decreased proliferation ability, decreased α-SMA expression, an increased ratio of collagen I/III, and increased TIMP1 and TIMP2 expression. Conversely, METTL3 overexpression significantly promoted the process of increased proliferation ability, increased α-SMA expression, decreased ratio of collagen I/III and decreased TIMP1 and TIMP2 expression in the soft matrix ( P <0.05). CONCLUSIONS Elevated ECM stiffness can promote excessive proliferation, differentiation, and abnormal ECM modulation, and the expression of METTL3 plays an important role in alleviating or aggravating matrix stiffness-induced vaginal fibroblast-to-myofibroblast differentiation and abnormal ECM modulation.
Humans ; Female ; Extracellular Matrix/metabolism* ; Cell Differentiation/genetics* ; Methyltransferases/metabolism* ; Pelvic Organ Prolapse/pathology* ; Fibroblasts/metabolism* ; Myofibroblasts/metabolism* ; Vagina/metabolism* ; Cell Proliferation/physiology* ; Cells, Cultured ; Middle Aged

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.
Female ; Humans ; Ligaments/pathology* ; Pelvic Organ Prolapse/metabolism* ; Postmenopause ; Animals ; Rats ; Adipogenesis/genetics* ; Recurrence ; Gene Expression Profiling ; Transcriptome ; Middle Aged ; Ovariectomy ; Protein Interaction Maps ; Aged ; Rats, Sprague-Dawley ; Uterus

Pelvic floor ultrasound can clearly visualize the position and morphology of pelvic floor organs, observe the pelvic organ prolapse in real-time, and quantify and analyze the degree of the levator ani muscle injury, which is the most common imaging method to assess the morphology and function of the levator ani muscle to date. The different ultrasound imaging techniques provide a variety of indicators, each with its own advantages and limitations.Furthermore, two-dimensional ultrasound is the basis of imaging, but it fails to detect cross-sectional images of the pelvic floor; three-dimensional ultrasound can acquire the axial plane of the levator hiatus; tomographic ultrasound imaging allows real-time observation of the levator ani muscle injury; shear wave elastography can provide a quantitative assessment of the contractility and elastic characteristics of the levator ani muscle in real-time. It is of great significance to summarize the basic principles of various ultrasound imaging techniques, summarize the ultrasound image characteristics of levator ani muscle and its hiatus in different populations and different states, and explore the cut-off values and diagnostic criteria-related ultrasound parameters for improving the diagnostic efficiency of pelvic floor ultrasound for levator ani muscle injury, leading to reducing missed diagnosis and misdiagnosis of lesions.
Humans ; Female ; Pelvic Floor/pathology* ; Pelvic Organ Prolapse/pathology* ; Ultrasonography/methods* ; Imaging, Three-Dimensional

To explore the risk factors for and the pathogenic mechanisms of pelvic organ prolapse and urinary incontinence.
 Methods: A total of 2 668 females who completed pelvic floor functional detection from July 2014 to October 2015 in the Physical Examination Center of the Third Xiangya Hospital of Central South University. The patients were divide into 4 groups: an urinary incontinence group, an organ prolapse group, an organ prolapse with urinary incontinence group, and a normal group. We compared the age, BMI, menopause, gravidity and parity, delivery pattern, the coordination of pelvic floor and abdominal muscles among the 4 groups.
 Results: There were statistical differences in age and BMI values among the 4 groups (P<0.05).There were statistical differences in menopause rate, gravidity and parity history among the normal group and the other 3 groups (P<0.05), and between the organ prolapse group and the organ prolapse with urinary incontinence group (P<0.05). However, the urinary incontinence group was not statistically different from the organ prolapse group and the normal group (P>0.05). In the mode of delivery, there were statistical difference among the normal group and the other 3 groups (P<0.05), and between the organ prolapse group with urinary incontinence group and the organ prolapse or the urinary incontinence group (P<0.05). There was no significant difference between the urinary incontinence group and the organ prolapse group (P>0.05). Among the 4 groups, the normal group was the best one in coordination between pelvic floor and abdominal muscles, following by the organ prolapse group, the pelvic organ prolapse group and the urinary incontinence group.
 Conclusion: Aging, menopause, number of pregnancies and delivery, BMI, and mode of delivery all affect the occurrence of pelvic organ prolapse and urinary incontinence. Females with urinary incontinence or organ prolapse are not good in coordination between the pelvic floor and abdominal muscles.
Female ; Humans ; Pelvic Floor ; pathology ; Pelvic Organ Prolapse ; pathology ; Pregnancy ; Risk Factors ; Urinary Incontinence ; pathology

Adult ; Female ; Humans ; Lupus Erythematosus, Systemic ; pathology ; physiopathology ; Pelvic Organ Prolapse ; pathology ; physiopathology ; Uterine Diseases ; pathology ; physiopathology ; Uterus ; pathology ; physiopathology ; Young Adult