Navigation Links
High-strain tendons repair less frequently

In a discovery that seems counterintuitive, a study appearing in the May 21st Journal of Biological Chemistry has found that tendons in high-stress and strain areas, like the Achilles tendon, actually repair themselves less frequently than low-stress tendons. This study sheds some light on the increased susceptibility of certain tendons to injury during aging.

Tendons, composed of collagen and other proteins, serve to connect muscle to bone and thus are vital for movement. Considering their strenuous activity, tendons need to be continually repairing collagen damage to avoid buildup of degraded proteins that could cause serious complications. Not all tendons are equal though; some tendons, like those in the hand, are primarily used to maintain proper limb placement while others, like the Achilles tendon in humans and the superficial digital flexor tendon (SDFT) in horses, have to bear a lot of weight and strain.

It would be expected that high-strain tendons would repair more frequently, yet Dr Helen Birch at University College London and colleagues examined protein turnover in the tendons of horses of various ages and found that the high-strain SDFT (located at the rear of the limb) repairs much less frequently than the low-strain common digital extensor tendon (CDET, located at the front of the limb). Birch and colleagues used an approach called amino acid racemization to measure protein age in the horse tendons. Amino acids are always incorporated into proteins in a specific orientation called the L-form, but afterwards can spontaneously convert into a mirror image called the D-form. Therefore, by measuring the ratio of L and D amino acids over time, one can estimate the half-life of a protein.

Through this method, the researchers found that non-collagen proteins in tendon have an average half life of 2.2 years in SDFT and 3.5 years in CDET, which would be expected. However, SDFT collagen had a half-life of 198 years, compared to 34 years for CDET collagen. That means that every year, only 0.25% of the injury-prone collagen gets replaced in SDFT tissue. Over time, degraded protein and other mechanically-induced micro-damage could reduce the overall integrity of the tendon, which could lead to large-scale injuries. As to why the body would seemingly put its more important tendons at greater risk, the researchers suggest that it may be a trade off; too much repair may compromise the strength and stiffness of these tendons which are used heavily, so the body tries to preserve their structural integrity at the expense of increased injury risk later in life.


Contact: Nick Zagorski
American Society for Biochemistry and Molecular Biology

Related biology news :

1. Engineers create bone that blends into tendons
2. Human derived stem cells can repair rat hearts damaged by heart attack
3. Pittsburgh scientists identify human source of stem cells with potential to repair muscle
4. Enzyme alerts cells powerful army to repair DNA damage
5. Seattle Childrens Hospital leads $23.7 million NIH grant to study gene repair
6. Simulation reveals how body repairs balance after damage
7. Using nanotubes to detect and repair cracks in aircraft wings, other structures
8. Enhanced DNA-repair mechanism can cause breast cancer
9. Yale receives $8.4 million to study DNA repair in cancer cells
10. Building the future -- 21st century nano tools to repair the nervous system
11. Researchers probe a DNA repair enzyme
Post Your Comments:
(Date:5/20/2016)...  VoiceIt is excited to announce its new ... By working together, VoiceIt and VoicePass will offer ... take slightly different approaches to voice biometrics, collaboration ... usability. Both ... "This marketing and technology partnership allows ...
(Date:5/9/2016)... , UAE, May 9, 2016 ... when it comes to expanding freedom for high net ... Even in today,s globally connected world, there is ... conferencing system could ever duplicate sealing your deal with ... obtaining second passports by taking advantage of citizenship via ...
(Date:4/28/2016)... First quarter 2016:   , Revenues amounted ... quarter of 2015 The gross margin was 49% (27) ... the operating margin was 40% (-13) Earnings per share ... operations was SEK 249.9 M (21.2) , Outlook   ... M. The operating margin for 2016 is estimated to ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... on a range of subjects including policies, debt and investment ... Speaking at a lecture to the Canadian Economics ... the country,s inflation target, which is set by both the ... "In certain areas there needs to be frequent ... not sit down and address strategy together?" He ...
(Date:6/23/2016)... WA (PRWEB) , ... June 23, 2016 , ... ... announces the release of its second eBook, “Clinical Trials Patient Recruitment and Retention ... recruitment and retention in this eBook by providing practical tips, tools, and strategies ...
(Date:6/23/2016)... 2016 A person commits a crime, and the ... track the criminal down. An outbreak of foodborne ... Administration (FDA) uses DNA evidence to track down the bacteria ... far-fetched? It,s not. The FDA has increasingly used a complex, ... foodborne illnesses. Put as simply as possible, whole genome sequencing ...
(Date:6/23/2016)... -- The Biodesign Challenge (BDC), a university competition that asks ... systems and biotechnology, announced its winning teams at the ... York City . The teams, chosen ... MoMA,s Celeste Bartos Theater during the daylong summit. Keynote ... of architecture and design, and Suzanne Lee , ...
Breaking Biology Technology: