Cartilage oligomeric matrix protein in canine spinal cord appears in the cerebrospinal fluid associated with intervertebral disc herniation.

STUDY DESIGN: Cerebrospinal fluid (CSF) from dogs with intervertebral disc herniation (IVDH) were analyzed using a specific antibody against cartilage oligomeric matrix protein (COMP). Immunolocalization and genetic expression of COMP were also examined in the spinal cords of mouse, rat, and dog. OBJECTIVE: To investigate the hypothesis that COMP is present in CSF of dogs with IVDH, and the clinical relevance of COMP expression in CSF as a potential biomarker of spinal cord injury. SUMMARY OF BACKGROUND DATA: In dog IVDH, diagnostic imaging is useful for determining the spinal cord compression, but less useful for assessment of traumatic degeneration. Aggrecan, a well-known component of cartilage matrix, is increased in CSF from cases of neural damage and inflammation of the spinal cord. METHODS: CSF from the cisterna magna (C-CSF) and the lumbar spine (L-CSF) of 19 dogs with IVDH and 5 normal dogs were analyzed using inhibition enzyme-linked immunosorbent assay (ELISA) and immunoblotting with an antibody cross-reactive with dog COMP. Samples of normal spinal cord from mouse, rat, and dog were also prepared for immunohistochemistry and in situ hybridization. RESULTS: ELISA values were significantly higher for L-CSF than for C-CSF in dogs with IVDH, whereas there was no significant difference between them in normal dogs. Immunoblots of L-CSF samples revealed positive bands of approximately 500 kDa in 6 cases of IVDH (positive cases), but no signal in negative cases. ELISA values were significantly higher in the positive cases than in the negative cases. Both COMP protein and mRNA were present at high levels in the gray matter of the spinal cord in all species. CONCLUSION: In dog IVDH, release of COMP from the spinal cord in association with injury may lead to COMP accumulation in L-CSF posterior to the site of disc extrusion, and therefore might be a predictive marker of spinal cord injury.

Gene and protein expression of cartilage oligomeric matrix protein associated with oncogenesis in canine tumors.

To investigate the expression of cartilage oligomeric matrix protein (COMP) associated with oncogenesis, samples of serum and tumor tissue were obtained from 25 dogs with tumors. The serum levels of COMP in dogs with tumors were significantly higher than in 38 normal controls and correlated with the concentrations of tumor tissue extracts. Positive bands to COMP antibody were detected on immunoblots of tumor extracts. Immunohistochemistry and in situ hybridization demonstrated positive signals of COMP and its mRNA in the cytoplasm of tumor cells from mammary gland tumors, but not in the normal mammary gland. Positive immunohistochemistry results were also obtained for COMP in mast cell tumor and melanoma cells. Oncogenesis might augment production of COMP and the serum level of COMP in dogs.

Effects of treatment with polysulfated glycosaminoglycan on serum cartilage oligomeric matrix protein and C-reactive protein concentrations, serum matrix metalloproteinase-2 and -9 activities, and lameness in dogs with osteoarthritis.

OBJECTIVE: To investigate the effects of polysulfated glycosaminoglycan (PSGAG) treatment on serum cartilage oligomeric matrix protein (COMP) concentration, matrix metal-loproteinase-2 (MMP-2) and -9 (MMP-9) activities, C-reactive protein (CRP) concentration, and lameness scores in dogs with osteoarthritis. ANIMALS: 16 dogs with osteoarthritis and 5 clinically normal dogs. PROCEDURES: Dogs with osteoarthritis had a history of chronic lameness, and osteophytes were observed on radiographic evaluation of the affected joint. Polysulfated glycosaminoglycan was administered IM twice a week for a total of 8 treatments to all dogs with osteoarthritis and to clinically normal control dogs. RESULTS: Lameness scores after PSGAG treatment in osteoarthritic dogs improved in 12 of the 16 dogs. Serum COMP concentrations in osteoarthritic dogs were significantly higher than in control dogs before treatment. Lameness scores in osteoarthritic dogs decreased significantly after treatment, compared with before treatment. Lameness scores of 9 dogs with hind limb lameness improved significantly after treatment; these dogs had corresponding decreases in serum COMP concentrations. After treatment, serum COMP concentrations and lameness scores of 7 dogs with forelimb lameness remained high and were significantly higher than those of dogs with hind limb lameness. Serum MMP-9 activities of dogs with forelimb lameness were significantly higher than in dogs with hind limb lameness after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: IM administration of PSGAG inhibited COMP degradation in dogs with osteoarthritis. Results indicate that decreases in serum COMP concentrations might be related to improvement in lameness after PSGAG treatment.

Computed tomographic evaluation of growth-related changes in the hip joints of young dogs.

OBJECTIVE: To evaluate changes in canine hip joint characteristics during growth via computed tomography (CT) and compare CT features of hip joints with and without laxity in young dogs placed in 2 imaging positions. ANIMALS: 21 dogs (42 hip joints). PROCEDURES: From 2 to 12 months after birth, CT examinations of the acetabulum of each hip joint in simulated normal standing and simulated weight-bearing positions were performed monthly for all dogs. Acetabular angle, dorsal acetabular rim angle (DARA), and femoral head diameter (FHd) were analyzed as skeletal variables; the lateral center edge angle (LCEA), dorsolateral subluxation (DLS) score, and center distance (CD) index were analyzed as joint laxity variables. At 12 months, all dogs underwent the Ortolani test to as-sess hip joint laxity. RESULTS: Hip joint laxity was detected in 5 dogs (10 joints) at 12 months of age; from 2 months, the acetabular angle and FHd increased and DARA decreased significantly until 5 months and the LCEA and DLS score increased significantly until 6 months. In nonlax hip joints in both positions, the CD index decreased significantly until 4 months of age and be-came stable thereafter. In lax hip joints, the CD index increased from 4 through 12 months; between 8 and 12 months, these changes were significantly greater in the weight-bearing position than in the standing position. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that CT-detected abnormalities in the DARA and CD index during body weight loading might be useful indicators of hip dysplasia in 2- to 6-month-old dogs.