Comparison of Biaxial Biomechanical Properties of Post-menopausal Human Prolapsed and Non-prolapsed Uterosacral Ligament

Abstract

Uterosacral ligaments (USLs) provide structural support to the female pelvic floor, and a loss of USL structural integrity or biomechanical function may induce pelvic organ prolapse (pop). Alterations in extracellular matrix composition and organization dictate USL mechanical function. changes in USL microstructure and corresponding mechanical properties, however, are not fully understood, nor is it understood how microstructure and mechanics change with onset and progression of pop. this is due, in part, as USL properties are primarily characterized along a single direction (uniaxial test), whereas the USL is loaded in multiple directions simultaneously within the body. Biaxial testing permits the acquisition of biomechanical data from two axes simultaneously, and thus simulates a more physiologic assessment compared to the traditional uniaxial testing. therefore, the objective of this study was to quantify the biaxial biomechanical properties and histological composition of the USL in post-menopausal women with and without pop at various stages. potential correlations between tissue microstructural composition and mechanical function were also examined. tangential modulus was lower and peak stretch higher in pop iii/iV compared to non-pop and pop i/ii in the main in vivo loading direction; however, no significant differences in mechanical properties were observed in the perpendicular loading direction. collagen content positively correlated to tangential modulus in the main in vivo loading direction (r = 0.5, p = 0.02) and negatively correlated with the peak stretch in both the main in vivo (r = −0.5, p = 0.02) and perpendicular loading directions (r = −0.3, p = 0.05). However, no statistically significant differences in USL composition were observed, which may be due to the small sample size and high variability of small sections of human tissues. These results provide first step towards understanding what microstructural and mechanical changes may occur in the USL with pop onset and progression. Such information may provide important future insights into the development of new surgical reconstruction techniques and graft materials for pop treatment.

A Deep Learning Framework for Predicting the Heterogeneous Stiffness Map of Brain White Matter Tissue

“…As a result, current biomechanical models simulating white matter tissue for various applications are intrinsically limited by the multiscale material properties employed. These challenges are not limited to brain tissue alone but are widespread across many hierarchical and connective tissues, including skin 97 , muscle 98 , ligaments 99 , arteries 100 , heart 101 , and intervertebral discs 102 . The proposed framework is a powerful tool to study the heterogeneity in the mechanical properties of the tissue as it counts the fiber volume fraction and the orientation of fibers.…”

Mapping Stiffness Landscape of Heterogeneous and Anisotropic Fibrous Tissue

“…As a result, current biomechanical models simulating white matter tissue for various applications are intrinsically limited by the multiscale material properties employed. These challenges are not limited to brain tissue alone but are widespread across many hierarchical and connective tissues, including skin 86 , muscle 87 , ligaments 88 , arteries 89 , heart 90 , and intervertebral discs 91 .…”

Roles and mechanisms of biomechanical-biochemical coupling in pelvic organ prolapse

“…In mechanically stretched healthy HVFs, the transcription levels of ITGs (ITGA1, ITGA4, ITGAV, and ITGB1) and matrix metalloproteinases (MMP2, MMP8, MMP13) are downregulated, leading to reduced ECM degradation. In stretched POP- HVFs, MMP1, MMP3, MMP10, ADAMTS8, ADAMTS13, TIMP1-3, ITGs (ITGA2, ITGA4, ITGA6, ITGB1), contactin 1 (CNTN1), cadherin A1, cadherin B1, and laminin (LN) were significantly upregulated, while COLs ( 1 , 4–6 , 11 , 12 ) and LOXL1 were downregulated. The downregulation of LOX inhibits the promoter activity of COL3A1, leading to impaired collagen synthesis.…”

“…Additionally, it has been proposed that this force is amplified in cases of multiple births and that persistent obesity can increase pressure on the abdomen ( 11 ). Impaired mechanics of the uterosacral ligament (USL) due to long-term forces is a key tissue in the pathogenesis of POP ( 12 ). Level I support includes the USL complex, which extends from the cervix to the sides of the uterus where it connects to the sacral surface; the USL plays a crucial role in supporting the uterus and vagina ( 13 , 14 ).…”