Speaker: Spencer Szczesny (Pennsylvania State University)
Title: Structural Determinants of Tendon Function During Development
Abstract: Tendons have a complex hierarchical collagenous structure that provides the tissue with unique tensile load-bearing capabilities essential for proper function. These functional capabilities are established during development within a short window of rapid structural change. While prior work has identified the numerous structural changes that occur during this developmental period (e.g., collagen content, crosslinking, fibril diameter and length), the key structural elements that are responsible for the abrupt increase in tendon mechanical functionality remain unclear. Additionally, the role of mechanical loading and other biological mechanisms during development in driving the observed structure-function changes in tendon are not fully characterized. To address this knowledge gap, we used computational modeling along with ultrastructural imaging, biochemical/thermodynamic assays, and multiscale mechanical testing to comprehensively investigate the dynamic structure-function relationships during late-stage embryonic chick development and to establish their sensitivity to mechanical stimulation. Our results suggest that the rapid increase in multiscale mechanics is primarily due to increases in fibril length, intrafibrillar crosslinking, and fibril area fraction. We also found that both intrafibrillar crosslink formation and fibril elongation are sensitive to mechanical loading. These findings provide critical insights into the biological and structural mechanisms that give rise to tensile load-bearing soft tissues and may help inform tissue engineering strategies to produce tendon/ligament replacements.