Differences in type II collagen turnover of osteoarthritic human knee and ankle joints.
We analysed hyaline cartilage of human knee and ankle joints for collagen and proteoglycan turnover in order to find differences in the metabolism and biochemical content of the extracellular matrix that could explain the higher prevalence of osteoarthritis (OA) in the knee joint, compared to the ankle joint.



Cartilage tissue from ankle and knee joints of OA patients were assessed for total collagen and proteoglycan content. For turnover, the aggrecan 846-epitope (CS 846), the type II collagen C-propeptide (CP2) and the collagenase-generated intrahelical cleavage neoepitope (C2C) were quantified.



Molecular analyses showed that type II collagen turnover (CP2 and C2C) was significantly elevated in the ankle, whereas aggrecan turnover (CS 846), total proteoglycan and total collagen were comparable between both joints. Analysis of the inter-relationships in the components of cartilage matrix turnover showed a significant positive correlation of C2C vs CP2.



The data suggest an increased type II collagen turnover in ankle vs knee OA cartilage but a comparable aggrecan turnover and comparable contents of type II collagen and proteoglycan. These findings point towards a focused attempt in advanced OA cartilage to structurally repair the collagen network that was more pronounced in the ankle joint and may explain in part the higher prevalence of OA in the knee as compared to the ankle joint.
Center of Orthopaedic and Trauma Surgery, Ingolstadt Hospital, Krumenauerstrasse 25, 85049, Ingolstadt, Germany. kontakt@matthias-aurich.de.|Department of Trauma, Hand and Reconstructive Surgery, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany. kontakt@matthias-aurich.de.|Department of Biochemistry, Rush Medical College, 1735 W. Harrison St., Chicago, IL, 60612, USA. kontakt@matthias-aurich.de.
Matthias
0000-0002-9039-1687
M
Aurich
Department of Trauma, Hand and Reconstructive Surgery, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.
Gunther O
GO
Hofmann
Laboratory for Cell and Tissue Engineering, Department of Orthopaedics and Trauma Surgery, Medical Center, Albert Ludwigs University of Freiburg, Faculty of Medicine, Hugstetter Straße 55, 79106, Freiburg, Germany.|Center for Biomedical Engineering, Massachusetts Institute of Technology, 500 Technology Sq, Cambridge, MA, 02139, USA.
Bernd
B
Rolauffs
D000368:Aged; D053674:Aggrecans / Q000378:metabolism; D000843:Ankle Joint / Q000378:metabolism* / Q000473:pathology; D002358:Cartilage, Articular / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D007118:Immunoassay; D007719:Knee Joint / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism
D053674:Aggrecans; D024043:Collagen Type II; D011509:Proteoglycans
Ankle; Cartilage; Human; Knee; Metabolism; Osteoarthritis