TY - JOUR

T1 - Mechanical properties of human patellar tendon collagen fibrils. An exploratory study of aging and sex

AU - Svensson, Rene B.

AU - Eriksen, Christian S.

AU - Tran, Peter H.T.

AU - Kjaer, Michael

AU - Magnusson, S. Peter

N1 - Publisher Copyright: © 2021 The Authors

PY - 2021

Y1 - 2021

N2 - Tendons are connective tissues that transmit mechanical forces from muscle to bone and consist mainly of nano-scale fibrils of type I collagen. Aging has been associated with reduced mechanical function of tendons at the whole-tendon level and also with increased glycation of tendon collagen fibrils. Yet, the mechanical effects of aging at the fibril level remain unknown. In vitro glycation has previously been reported to substantially increase fibril strength and stiffness in young rats, suggesting a potentially large effect of aging through the glycation mechanism. We therefore expected that aging would have a similar major impact on fibril mechanical properties. In addition, differences in fibril mechanical properties between men and women have never been studied. This study investigated human patellar tendon biopsies from young (26 ± 4 years) and elderly (66 ± 1 years), men and women by measuring the mechanical properties of individual collagen fibrils using a custom nano-mechanical device. There were no major mechanical differences with either age or sex, but there were modestly greater failure stress (22%) and tensile modulus at both low and high strain (16% and 26% respectively) in the elderly group. No significant differences in mechanical properties were observed between men and women. The slightly greater strength and stiffness in the elderly group are in contrasts to the age-related deficits observed for whole-tendons in vivo, although the study was not designed to investigate these minor differences.

AB - Tendons are connective tissues that transmit mechanical forces from muscle to bone and consist mainly of nano-scale fibrils of type I collagen. Aging has been associated with reduced mechanical function of tendons at the whole-tendon level and also with increased glycation of tendon collagen fibrils. Yet, the mechanical effects of aging at the fibril level remain unknown. In vitro glycation has previously been reported to substantially increase fibril strength and stiffness in young rats, suggesting a potentially large effect of aging through the glycation mechanism. We therefore expected that aging would have a similar major impact on fibril mechanical properties. In addition, differences in fibril mechanical properties between men and women have never been studied. This study investigated human patellar tendon biopsies from young (26 ± 4 years) and elderly (66 ± 1 years), men and women by measuring the mechanical properties of individual collagen fibrils using a custom nano-mechanical device. There were no major mechanical differences with either age or sex, but there were modestly greater failure stress (22%) and tensile modulus at both low and high strain (16% and 26% respectively) in the elderly group. No significant differences in mechanical properties were observed between men and women. The slightly greater strength and stiffness in the elderly group are in contrasts to the age-related deficits observed for whole-tendons in vivo, although the study was not designed to investigate these minor differences.

KW - Advanced glycation

KW - Brittleness

KW - Cross-link

KW - Failure strength

KW - Gender

U2 - 10.1016/j.jmbbm.2021.104864

DO - 10.1016/j.jmbbm.2021.104864

M3 - Journal article

C2 - 34607298

AN - SCOPUS:85116001589

VL - 124

JO - Journal of the Mechanical Behavior of Biomedical Materials

JF - Journal of the Mechanical Behavior of Biomedical Materials

SN - 1751-6161

M1 - 104864

ER -