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Pelvic Floor Disorders (PFDs) Research

1. Introduction to Pelvic Floor Disorders

1.1 Background

1.1.1 High Morbidity and Negative Impact

• Pelvic floor disorders (PFDs) are associated with high morbidity and have a significant negative impact on the quality of life.
• Pelvic floor muscles (PFMs) dysfunction, commonly identified after vaginal delivery, is a leading risk factor for PFDs.

1.1.2 Lack of Fundamental Knowledge

• There is a lack of fundamental knowledge regarding the tissue and cellular alterations that govern PFM dysfunction.
• The underlying mechanisms of PFDs after parturition remain elusive.

1.1.3 Lack of Effective Strategies

• There are few effective strategies for recovery with minimal morbidity.
• Efforts to potentiate constructive remodeling of PFMs after birth injury are required to prevent PFM deterioration.

1.2 Research Objectives

1.2.1 Proposed Mechanisms

• Investigate the efficacy of decellularized porcine skeletal muscle extracellular matrix (ECM) hydrogel (SKM) in preventing and treating pathological PFM alterations consequent to birth injury.

1.2.2 Research Questions

• Explore the precise mechanisms of PFM dysfunction after parturition.
• Characterize alterations in the intrinsic PFM components in women with PFDs.
• Determine the downstream events after PFM birth injury.

1.3 Research Methodology

1.3.1 Experimental Design

• Biopsied the pubovisceralis portion of levatorani from vaginally nulliparous (VN) and parous (VP) cadaveric donors and parous women with symptomatic POP.
• Examined early and delayed PFM responses to simulated birth injury (SBI) using the rat model.

1.3.2 Sample Collection and Analysis

• Histological, immunohistochemical, gene expression, and flow cytometry analyses were used to investigate PFM response to birth injury.
• The sample size was calculated a priori, and outliers were not excluded.

2. Pelvic Floor Muscles (PFMs) Morphological Properties

2.1 PFMs in Parous Women with Symptomatic Pelvic Organ Prolapse (POP)

2.1.1 Atrophy and Fibrosis

• PFMs exhibit atrophy and fibrotic degeneration in parous women with symptomatic POP.
• The smaller fiber size was accompanied by increased collagen content in the POP group compared with the controls.

2.1.2 Muscle Stem Cells (MuSCs) Differentiation and Self-renewal

• Muscle stem cells are indispensable for muscle regeneration.
• The myogenesis pathway was up-regulated early on and decreased the expression of genes related to inflammation and ECM remodeling.

2.1.3 Inflammatory Response

• A sustained inflammatory response of the PFMs follows SBI in rats.
• Gene expression analysis indicated that birth injury led to impairment in PFM anabolism and a persistent inflammatory response.

2.2 SKM for PFM Recovery

2.2.1 Prevention of Atrophy and Fibrosis

• SKM treatment at the time of birth injury up-regulated genes in the myogenesis pathway early on and decreased the expression of genes related to inflammation and ECM remodeling.
• SKM administration 4 weeks after birth injury could mitigate PFM atrophy and fibrosis long term.

2.2.2 Gene Expression Analysis

• Gene expression analysis demonstrated that the changes are mainly driven by the hydrogel-induced enhancement of endogenous myogenesis, ECM remodeling, and modulation of the immune response.

3. Conclusion

3.1 Research Findings

• PFMs exhibit atrophy and fibrosis in parous women with symptomatic POP.
• The inflammatory response of PFMs after SBI negatively affects pathways related to muscle growth, ECM remodeling, and vascularization.
• SKM administration at the time of birth injury or 4 weeks after injury mitigates PFM atrophy and fibrosis.

3.2 Future Directions

• Further studies are needed to explore the mechanisms underlying the efficacy of SKM in preventing and treating PFDs.
• Clinical trials are warranted to validate the translational relevance of these findings.

3.3 Implications

• The findings of this study have important implications for the prevention and treatment of PFDs.
• SKM represents a promising therapeutic approach for the management of PFDs, with the potential for minimal morbidity. """