Journal article
Age‐Related changes in cartilage proteoglycans: Quantitative electron microscopic studies
Microscopy research and technique, Vol.28(5), pp.398-408
08/01/1994
DOI: 10.1002/jemt.1070280506
PMID: 7919527
Abstract
Biochemical and biophysical studies have shown that the composition and sedimentation velocity of cartilage proteoglycans change with age, but these investigations cannot demonstrate the alterations in molecular structure responsible for these changes. Development of quantitative electron microscopic methods has made it possible to define the age‐related structural changes in aggregating proteoglycans and to correlate the alterations in their structure with changes in tissue composition and morphology. Electron microscopic measurement of human and animal hyaline cartilage proteoglycans has shown that with increasing age the length of the chondroitin sulfate–rich region of aggregating proteoglycan monomers (aggrecan molecules) decreases, the variability in aggrecan length increases, the density of aggrecan keratan sulfate chains increases, the number of monomers per aggregate decreases, and the proportion of monomers that aggregate declines. Proteoglycans from the nucleus pulposus of the intervertebral disc show similar but more dramatic age‐related alterations. At birth, nucleus pulposus aggrecan molecules are smaller and more variable in length than those found in articular cartilage. Within the first year of human life, the populations of aggregates and large aggrecan molecules analogous to those found in articular cartilage decline until few if any of these molecules remain in the central disc tissues of skeletally mature individuals. The mechanisms of the age‐related changes in cartilage proteoglycans have not been fully explained, but measurement of proteoglycans synthesized by chondrocytes of different ages suggests that alterations in synthesis produce at least some of the age‐related changes in aggrecan molecules. Degradation of aggrecan chondroitin sulfate–rich regions in the matrix probably also contributes to the structural changes seen by electron microscopy. Age‐related changes in proteoglycan aggregation may be due to alterations in link protein function or inhibition of aggregation of newly synthesized aggrecan molecules by accumulation of degraded aggrecan molecules. © 1994 Wiley‐Liss, Inc.
Details
- Title: Subtitle
- Age‐Related changes in cartilage proteoglycans: Quantitative electron microscopic studies
- Creators
- Joseph A BuckwalterPeter J RoughleyLawrence C Rosenberg
- Resource Type
- Journal article
- Publication Details
- Microscopy research and technique, Vol.28(5), pp.398-408
- DOI
- 10.1002/jemt.1070280506
- PMID
- 7919527
- NLM abbreviation
- Microsc Res Tech
- ISSN
- 1059-910X
- eISSN
- 1097-0029
- Publisher
- Wiley Subscription Services, Inc., A Wiley Company; Hoboken
- Number of pages
- 11
- Language
- English
- Date published
- 08/01/1994
- Academic Unit
- Stead Family Department of Pediatrics; Orthopedics and Rehabilitation; Injury Prevention Research Center
- Record Identifier
- 9984040328902771
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