Mechanical properties of human patellar tendon collagen fibrils. An exploratory study of aging and sex. (December 2021)

• Record Type: Journal Article
• Authors: Svensson, Rene B.; Eriksen, Christian S.; Tran, Peter H.T.; Kjaer, Michael; Magnusson, S. Peter
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 124(2021)
• Publication Date: 2021-12
• Subjects: Advanced glycation -- Brittleness -- Cross-link -- Failure strength -- Gender; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2021.104864
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: 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. Graphical abstract: Image 1 Highlights: First mechanical measurements of aging and sex in human collagen fibrils. Modestly greater mechanical properties in elderly, primarily at high strain. No indication of fibril brittleness in elderly. No significant sex differences observed within the limits of this exploratory study.