Aging and matrix viscoelasticity affect multiscale tendon properties and tendon derived cell behavior.

Area of Science:

• Biomedical Engineering
• Musculoskeletal Biology
• Cellular Mechanics

Background:

• Aging is a primary risk factor for Achilles tendon disorders and rupture.
• While macroscale properties decline with age, the impact on multiscale viscoelasticity and cell behavior is less understood.

Purpose of the Study:

• To investigate age-related changes in multiscale Achilles tendon properties.
• To determine how microscale mechanics influence tendon cell behavior during aging.

Main Methods:

• Characterized native tendon mechanical and structural properties across scales.
• Utilized nanoindentation to assess mechanical properties.
• Employed alginate hydrogels mimicking juvenile tendon mechanics to study cell responses.

Main Results:

• Identified dose-dependent changes in multiscale tendon properties with aging.
• Nanoindentation properties correlated with tensile mechanics and echogenicity.
• Stiffness and viscoelasticity in juvenile-mimicking hydrogels affected cell aspect ratio and proliferation.

Conclusions:

• Aging significantly alters Achilles tendon multiscale mechanical and structural properties.
• Viscoelasticity plays a crucial role in controlling tendon-derived cell morphology and proliferation.
• Findings offer insights into age-related tendon degeneration and potential therapeutic targets.