AGE-RELATED-CHANGES IN PROTEOGLYCANS OF HUMAN INTERVERTEBRAL DISKS

The age-related changes in glycosaminoglycan composition of human inte rvertebral discs were studied. A large number of tissue samples taken from 301 individuals at autopsy or at operation of prolapsed discs wer e investigated. It was found that the aging process is accompanied by a progressive decrease in GAGs content, both in annulus fibrosus and i n nucleus pulposus. The GAG: collagen ratio significantly decreases. T he KS and Ch-6-S were found to be the most abundant GAGs in both parts of the disc and their amounts decrease during the aging. A distinct, age-related increase of KS/Ch-S and Ch-6-S/Ch-4-S ratios was observed. Significant quantitative differences between the GAGs contents in nor mal and prolapsed discs were found. The nuclei pulposi of prolapsed di scs contained less GAGs, especially KS and Ch-6-S, in comparison to no rmal tissue of the same age. Also, the age-related decline of GAGs: co llagen ratio is more distinct in prolapsed discs. It seems that these differences in GAGs composition may be important in the mechanism of p redisposition to disc prolapse.