Intramuscular collagen cross‐linking in aging men and women

Abstract

The connective tissue components of skeletal muscle are primarily comprised of collagen and play a critical role in maintaining muscle structure and transfer of force from contractile elements to the bone. Collagen tensile strength and stability is achieved through both intra- and intermolecular cross-linking. Data from animals have shown that aging skeletal muscle accumulates cross-links which may play a role in reduced muscle function. We hypothesized the collagen cross-link concentration of old individuals would be greater than young, thus suggesting a mechanism that contributes to reduced muscle function. Intramuscular (vastus lateralis) collagen cross-links (pyridinoline) were determined in 18 young (9 M; 9 W; age 25±1) and 22 old individuals (10 M; 12 W; age 77±1) after CF1 extraction from muscle hydrolyzates. Cross-links were expressed relative to collagen content (APS#7649) as mmol pyridinoline • mole collagen−1. The degree of intramuscular collagen cross-linking was not affected by age (young: 395±65; old: 351±45) or gender (men: 402±58; women: 343±50). These results suggest that the age related decline in whole muscle function is not related to increases in intramuscular collagen cross-linking. Supported by NIH grants R01 AG020532, R21 AG15833 and K01 AG00831.