Products resulting from cleavage of the interglobular domain of aggrecan in samples of synovial fluid collected from dogs with early- and late-stage osteoarthritis.
ABSTRACT To investigate interglobular domain (IGD) cleavage of aggrecan in dogs with naturally developing osteoarthritis (OA).
Samples of synovial fluid (SF) obtained from 3 cubital (elbow) joints and 3 stifle joints of 4 clinically normal dogs, 24 elbow joints of 12 dogs with early-stage OA, 8 stifle joints of 5 dogs with early-stage OA, and 10 stifle joints of 9 dogs with late-stage OA.
Fractions of SF were assayed for total glycosaminoglycan (GAG) content and also subjected to Western blot analysis by use of monoclonal antibodies against neoepitopes generated by cleavage of the IGD of the aggrecan protein core by matrix metalloproteinase (MMP; BC-14) and aggrecanase (BC-3).
Total GAG content of SF from joints of clinically normal dogs did not differ from that of dogs with early-stage OA. The GAG content of SF from joints of dogs with late-stage OA was significantly lower, compared with GAG content for other SF samples. Aggrecanase-generated fragments were detected in SF from all groups but not in all samples. Matrix metalloproteinase-generated fragments were not detected in any SF samples. In early-stage OA, high-molecular-weight aggrecanase-generated aggrecan catabolites were evident.
GAG content of SF obtained from dogs with late-stage OA is significantly decreased, suggesting proteoglycan depletion of cartilage. Aggrecanases, but not MMPs, are the major proteolytic enzymes responsible for IGD cleavage of aggrecan in canine joints. Analyses of SF samples to detect aggrecanase-generated catabolites may provide an early biomarker for discriminating early- and late-stage OA in dogs.
Article: Evaluation of a collagenase generated osteoarthritis biomarker in naturally occurring canine cruciate disease.[show abstract] [hide abstract]
ABSTRACT: To determine the clinical value of a novel osteoarthritis (OA) biomarker in detecting canine cruciate disease. Cross sectional clinical study. Dogs (n=22) with cranial cruciate ligament (CCL) rupture and 12 control dogs. Concentrations of collagenase-generated cleavage epitope of type II collagen (Col2-3/4C(long mono), or C2C) in serum, urine, and joint fluid were compared between a group of dogs with CCL rupture and a control group. Correlation of C2C concentrations to the clinical stage of stifle OA was also evaluated. There were no significant differences in C2C concentrations in serum, urine, and joint fluid between groups (P>.05). Subjective scores of lameness, joint effusion, osteophytosis were significantly more severe in the CCL rupture group compared with the control group (P<.05). There was no significant correlation of C2C concentrations with clinical stage of stifle OA (P>.05). This OA biomarker did not detect pathology associated with CCL rupture. Our results suggest that collagenase-specific degradation of type II collagen in articular cartilage may not be involved in the early stage of naturally occurring canine cruciate disease, and that pathology associated with naturally occurring CCL rupture is different from that of experimental OA model. C2C is not clinically useful in detecting CCL rupture in dogs.Veterinary Surgery 01/2009; 38(1):117-21. · 1.26 Impact Factor
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ABSTRACT: Osteoarthritis is the most common arthropathy of mammalian species including cats. Cartilage degradation is central to the disorder and here we present, for the first time, an in vitro model of feline cartilage degradation which will be useful for further studies in this target species. Feline articular cartilage explant cultures were maintained for 28 days and in the presence of oncostatin M with and without interleukin (IL)-17, tumour necrosis factor (TNF), IL-1alpha, or IL-1beta. Media samples and digested cartilage explants were analysed for glycosaminoglycan (GAG) and collagen content. The combination of IL-1beta and OSM, both at 20 ng/ml, was able to promote GAG release to the greatest extent at 14 days. At 28 days, all groups showed relatively high release of GAG. At 14 days, only IL-1beta and OSM in combination were associated with a statistically significant increase in collagen release over and above control tissue. IL-1beta dose-response studies showed that an IL-1beta dose of 10 ng/ml promotes a statistically significant increase in GAG breakdown when used with OSM, and higher doses of IL-1beta did not result in significantly greater response. The model demonstrated both GAG and collagen degradation and will be of use for further understanding of feline cartilage metabolism and for screening of potential structure-modifying agents to be used in cats.Journal of feline medicine and surgery. 08/2010; 12(8):614-20.