Collagen turnover in normal and degenerate human intervertebral discs as determined by the racemization of aspartic acid

Collagen turnover in normal and degenerate human intervertebral discs as determined by the racemization of aspartic acid

TNO Kwaliteit van Leven
Sivan, S.S.
Wachtel, E.
Tsitron, E.
Sakkee, N.
van der Ham, F.
Groot, J.de
Roberts, S.
Maroudas, A.

2008

Knowledge of rates of protein turnover is important for a quantitative understanding of tissue synthesis and catabolism. In this work, we have used the racemization of aspartic acid as a marker for the turnover of collagen obtained from healthy and pathological human intervertebral disc matrices. We measured the ratio of the D- and L-isomers in collagen extracted from these tissues as a function of age between 16 and 77 years. For collagen taken from healthy discs, the fractional increase of D-Asp was found to be 6.74 × 10 -4/year; for degenerate discs, the corresponding rate was 5.18 × 10-4/year. Using the racemization rate found previously for the stable population of collagen molecules in dentin, we found that the rate of collagen turnover (kT) in discs is not constant but rather a decreasing function of age. The average turnover rate in normal disc between the ages of 20 and 40 is 0.00728 ± 0.00275/year, and that between the ages of 50 and 80 is 0.00323 ± 0.000947/year, which correspond to average half-lives of 95 and 215 years, respectively. Turnover of collagen from degenerate discs may be more rapid than that found for normal discs; however, statistical analysis leaves this point uncertain. The finding of a similar correlation between the accumulation of D-Asp and that of pentosidine for three normal collagenous tissues further supports the idea that the accumulation of pentosidine in a particular tissue can, along with the racemization of aspartic acid, be used as a reliable measure of protein turnover. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc.

Acids
Histology
Implants (surgical)
Isomers
Organic acids
Population statistics
Probability density function
Aspartic acids
Collagen molecules
Collagenous tissues
Decreasing functions
Intervertebral discs
Pentosidine
Racemization rates
Statistical analysis
Turnover rates
Dextro aspartic acid
Arginine
Drug derivative
Lysine
Controlled study
Dentin
Half life time
Human tissue
Intervertebral disk
Intervertebral disk degeneration
Isomer
Protein metabolism
Racemization
Statistical analysis
Turnover time
Metabolism
Pathology
Spine disease
Adolescent
Adult
Age Factors
Aged
Arginine
Collagen
D-Aspartic Acid
Dentin
Female
Humans
Intervertebral Disk
Lysine
Male
Middle Aged
Spinal Diseases

http://resolver.tudelft.nl/uuid:33856f41-0bdd-4a30-bebf-c2959d1bcc3b

https://doi.org/10.1074/jbc.m709885200

240751

0021-9258

Journal of Biological Chemistry, 283 (283), 8796-8801

article