Pelvic organ prolapse (POP) occurs when pelvic organs descend beyond the vaginal canal and affects up to 50% of women, particularly after menopause. POP was previously treated using polypropylene mesh; however, its withdrawal due to adverse complications has led urogynaecologists to adopt alternative approaches, including autologous fascia lata (FL) grafts. Fascia
lata is a multilayered, dense fibrous connective tissue of the outer thigh that contributes to biomechanical function through tension regulation, venous return support, and joint stabilisation. However, the biomechanical strength and immunobiological properties of FL grafts, and how these characteristics are influenced by patient age, remain poorly understood. This knowledge gap raises
important questions about variability in graft performance and long-term surgical outcomes. Therefore, this study aims to characterise the immunobiological and biomechanical properties of fascia lata. The study aims to also determine how age influences these features, in order to inform evidence-based clinical use of autologous FL grafts for pelvic reconstruction use.

Fascia lata (FL) tissue was harvested from the lateral thigh using a ~3 cm transverse incision during sacrocolpopexy procedures, with a small surplus sample retained under ethical approval. Biomechanical properties were evaluated using uniaxial tensile testing on a CellScale UniVert tensiometer. Samples were trimmed into standardized strips, preconditioned, and stretched at a constant strain rate until failure to determine ultimate tensile strength, elastic modulus, and strain at break. To assess tissue composition and extracellular matrix organisation, sections underwent histological staining (H&E, Masson’s trichrome, and Picrosirius Red) to evaluate
collagen architecture, density, and fibre alignment. Immunofluorescence microscopy was performed to characterise matrix and cellular components, including collagen organisation, decorin distribution, and markers of myofibroblasts (α-SMA), endothelial cells (CD31), and stromal/progenitor populations (CD105, CD106). Imaging was analysed using quantitative image analysis to compare structural and cellular features across age groups.

There was no significant difference between the biomechanical properties of FL across age groups. Immunofluorescence revealed a localisation of decorin within the collagen matrix, and collagen I, III & V were expressed extensively across the fibrous component. Moreover, we discovered the presence of α-SMA, CD31, CD105 and CD106 in HFL. Our ongoing analysis is looking into a multiplex of immune markers across all age groups.

The detection of collagen and decorin within the FL allowed us to assess if this is impacted by age. The diffrences were found to be non-significant.

Having no difference in biomechanical properties between age groups demonstrates that autologous FL grafts may be effective across all ages. This research could help improve the understanding of autologous grafts and optimise their real-world applications.