Regional collagen turnover and composition of the human patellar tendon
Cheng Zhang, japplphysiol 12 MAR 2020
Tendon pathology (tendinopathy) typically occurs in specific regions of a tendon and growth in response to exercise also appears to be more pronounced in specific regions. In a previous study in animals we found evidence of regional differences in tendon turnover, but whether the turnover of human patellar tendon differs in different regions still remains unknown. Patellar tendons were obtained from cadavers of healthy men and women (body donation program, n=5, >60 years of age). Samples were taken from 10 different regions along the length, width and thickness of the tendon. Turnover was measured by 14C bomb-pulse dating, and also estimated from the accumulation of advanced glycation end-products (AGEs) by fluorescence (340/460 Nutrimuscle) in addition to measurement of specific AGEs by mass-spectrometry.
Composition in terms of collagen, glycosaminoglycans (GAGs) and DNA was also assessed in each region. 14C results showed that all tendon regions had a similar 14C concentration, which was equal to the average atmospheric 14C concentration during the first 15 years of the person's life. Fluorescence normalized to dry weight did not differ between regions, nor did specific AGEs. Higher GAG content was observed in the proximal and near the distal insertion of the tendon. In conclusion, healthy human patellar tendon display no regional differences in collagen turnover throughout life.
