Objective—To determine the effects of 2 doses of recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge (rhBMP-2/ACS) on bone healing in dogs.
Animals—27 adult dogs.
Procedures—Dogs underwent a mid-diaphyseal (1-mm) tibial osteotomy (stabilized with external skeletal fixation) and received an ACS containing 0.28 mg (0.2 mg/mL) or 0.56 mg (0.4 mg/mL) of rhBMP-2 or no treatment (control dogs). All dogs were examined daily; bone healing was assessed via radiography and subjective lameness evaluation every 2 weeks. After euthanasia at 8 weeks, tibiae were evaluated biomechanically and histologically.
Results—Control dogs required antimicrobial treatment for pin-site–related complications more frequently than did rhBMP-2/ACS–treated dogs. At 4 and 6 weeks, weight bearing was greater in dogs treated with rhBMP-2/ACS (0.2 mg/mL) than in control dogs, albeit not significantly. Compared with control treatment, both doses of rhBMP-2/ACS accelerated osteotomy healing at 4, 6, and 8 weeks, and the 0.2 mg/mL dose enhanced healing at 2 weeks; healing at 6 weeks was greater for the lower-dose treatment than for the higher-dose treatment. Histologically, healing at 8 weeks was significantly improved for both rhBMP-2/ACS treatments, compared with control treatment. Among groups, biomechanical variables did not differ, although less osteotomy-site failures occurred in rhBMP-2/ACS–treated groups.
Conclusions and Clinical Relevance—In dogs that underwent tibial osteotomy, rhBMP-2/ACS (0.2 mg/mL) appeared to accelerate bone healing and reduce lameness (compared with control treatment) and apparently augmented bone healing more than rhBMP-2/ACS (0.4 mg/mL). Compared with control dogs, rhBMP-2/ACS–treated dogs required antimicrobial treatments less frequently.
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.
Objective—To quantitatively evaluate contact area under 2 loads and subjectively compare contact areas with subchondral bone (SCB) density patterns in intact metacarpophalangeal joints of horses.
Sample Population—6 forelimbs from horses without musculoskeletal disease.
Procedures—Computed tomographic scans of intact metacarpophalangeal joints were analyzed to obtain SCB density measurements. Each limb was loaded on a materials testing system to 150° and 120° extension in the metacarpophalangeal joint, and the joint was stained via intra-articular injection with safranin-O or toluidine blue, respectively. Each joint was disarticulated, and the surface area was digitized. Total articular surface area, contact area, and percentage contact area at each angle were calculated for the distal third metacarpal condyles, the proximal phalanx, and the proximal sesamoid bones.
Results—Contact area on the third metacarpal condyles, proximal sesamoid bones, and the proximal phalanx significantly increased with increased load. Areas of contact subjectively appeared to have a higher density on computed tomographic scans.
Conclusions and Clinical Relevance—Areas consistently in contact under higher load were associated with increased SCB density. This supports the idea that the SCB adapts to the load applied to it. As load increased, contact area also increased, suggesting that areas not normally loaded may have a high degree of stress during impact loading. Quantifying how contact in the joint changes under different loading conditions and the adaptation of the bone to this change in normal and abnormal joints may provide insight into the pathogenesis of osteochondral disease.
Objective—To evaluate and correlate patterns of subchondral bone density and articular cartilage degeneration (derived by use of gross, histologic, and computed tomographic [CT] examinations) in equine third metacarpal condyles with and without osteoarthritis.
Sample Population—8 metacarpophalangeal (MCP) joints (n = 4 horses) without osteoarthritis and 6 osteoarthritis-affected MCP joints (4).
Procedures—Horses were euthanized. The third metacarpal condyles of the joints were examined grossly and via CT (3 slice images/condyle). For 6 condylar zones, mean bone density and pattern of density distribution were determined. Data for osteoarthritis-affected and control joints were compared. Histomorphometric point count analyses identified areas of bone density for comparison with CT density measurements.
Results—Osteoarthritis-affected condyles had heterogeneous subchondral bone with focal resorptive lesions and patterned sclerosis, whereas control condyles had symmetric bone density distribution. In osteoarthritis-affected condyles, bone density determined via gray scale image density analysis was greater (dorsal and medial pattern), compared with control condyles, and differed among zones because of resorption and sclerosis. With regard to bone density in osteoarthritis-affected condyles, histologic findings correlated with CT images, and bone lesions were significantly correlated with cartilage lesions.
Conclusions and Clinical Relevance—In horses, heterogeneous distribution and greater subchondral bone density were characteristic of osteoarthritis-affected condyles, compared with control condyles. Subchondral bone lesions correlated with overlying cartilage lesions in osteoarthritis-affected MCP joints. Identification of CT image characteristics appears to predict the presence of a cartilage lesion in MCP joints of horses with osteoarthritis.
Objective—To compare and validate goniometric joint measurements obtained from nonsedated and sedated cats with measurements from radiographic evaluation.
Animals—20 adult cats with no evidence of joint disease.
Procedures—Measurements of flexion and extension of the carpus, elbow, shoulder, tarsus, stifle, and hip joints and of carpal and tarsal joints during varus and valgus angulation were made by a single investigator before and after sedation of cats. Measurements were made by use of a goniometer with a masked dial. Joint angle measurements were compared between nonsedated and sedated cats and also with measurements from radiographs made while cats were sedated. Each series of measurements was repeated 4 times. To evaluate repeatability, Cronbach α values were calculated for repeated measure results of goniometric joint measurements of nonsedated and sedated cats. An intraclass correlation was calculated to determine reliability among the 3 measurement types (ie, measurements from nonsedated and sedated cats and on radiographic evaluation).
Results—Joint measurements did not differ significantly by measurement type, when comparing radiographic measurements with goniometric measurements in sedated and nonsedated cats. Cronbach α values were > 0.99 for goniometric joint measurements within individual nonsedated and sedated cats and also for comparison of mean meaurements obtained from sedated cats versus nonsedated cats versus radiographs. An intraclass correlation of 0.999 revealed high reliability among measurement types.
Conclusions and Clinical Relevance—Results indicated that goniometric joint measurements in nonsedated and sedated cats are repeatable and valid.
Objective—To determine effects of glucosamine (GLN) and chondroitin sulfate (CS) on expression of genes encoding putative mediators of osteoarthritis in bovine cartilage explants cultured for 2 weeks.
Sample Population—Articular cartilage explants harvested from carpal joints of 4 Holstein steers after slaughter.
Procedures—Cartilage disks were treated as follows: fetal bovine serum only (control treatment), human recombinant interleukin (IL)-1β (50 ng/mL; IL-1 treatment), GLN (5 μg/mL) with addition of CS (20 μg/mL; GLN-CS treatment), and human recombinant IL-1β (50 ng/mL) with addition of GLN and CS (IL-1–GLN-CS treatment). Media were analyzed for nitric oxide and prostaglandin E2 (PGE2) release. Explants were subjected to quantitative real-time PCR analysis; expressions of mRNA for inducible nitric oxide synthase, cyclooxygenase-2, microsomal prostaglandin E synthase 1, matrix metalloproteinase (MMP)-3 and -13, aggrecanase-1 and -2, tissue inhibitor of metalloproteinase (TIMP)-3, type II collagen, and aggrecan were assessed.
Results—IL-1–GLN-CS and GLN-CS treatments decreased nitrite release, compared with IL-1 treatment; IL-1–GLN-CS treatment decreased IL-1–induced PGE2 release. Expressions of inducible nitric oxide synthase, cyclooxygenase-2, and microsomal prostaglandin E synthase 1 mRNA were abrogated by GLN-CS and IL-1–GLN-CS treatments. Interleukin-1–induced mRNA expressions of proteolytic enzymes were diminished by IL-1–GLN-CS treatment. Compared with control treatment, GLN-CS treatment decreased MMP-3 and aggrecanase-2 mRNA expression. Transcripts of TIMP-3 were increased by IL-1–GLN-CS treatment, compared with IL-1 treatment. Genes encoding type II collagen and aggrecan on day 14 were upregulated by GLN-CS and IL-1–GLN-CS treatments, compared with control treatment.
Conclusions and Clinical Relevance—Treatment with GLN and CS consistently downregulated mRNA expression for inflammatory mediators and matrix degrading enzymes while increasing TIMP-3 transcripts.
Objective—To examine the ability of preemptive administration of a proprietary neurokinin-1 (NK1) receptor antagonist to attenuate limb dysfunction associated with monosodium urate–induced synovitis in the stifle joints of dogs.
Animals—16 clinically normal adult mixed-breed dogs (8 males and 8 females).
Procedures—A crossover study was conducted in 2 phases. Dogs were assigned to 2 groups (8 dogs/group) and orally administered an NK1 receptor antagonist (3 mg/kg) or a control substance once daily for 4 days. Synovitis was then induced in the left stifle joint by intra-articular injection of monosodium urate. Investigators were not aware of treatment group assignments. Dogs were evaluated by use of subjective lameness scores during standing, walking, and trotting and by use of ground reaction force data 3, 6, 9, 12, and 24 hours after urate injection. After a 21-day washout period, the experiment was repeated with each dog administered the other treatment and injected with monosodium urate in the contralateral stifle joint.
Results—No significant differences were detected between the NK1 receptor antagonist and control treatments with regard to peak vertical force, vertical impulse area, or subjective evaluations of lameness during standing, walking, or trotting, except during walking 24 hours after monosodium urate injection.
Conclusions and Clinical Relevance—Preemptive administration of an NK1 receptor antagonist failed to significantly improve subjective or objective outcome measures in dogs with monosodium urate–induced synovitis.
Objective—To evaluate the use of a combination of avocado and soybean unsaponifiable (ASU) extracts for the treatment of experimentally induced osteoarthritis in horses.
Procedures—Osteoarthritis was induced via osteochondral fragmentation in 1 middle carpal joint of each horse; the other joint underwent a sham operation. Horses were randomly allocated to receive oral treatment with ASU extracts (1:2 [avocado-to-soybean] ratio mixed in 6 mL of molasses; n = 8) or molasses (6 mL) alone (placebo treatment; 8) once daily from days 0 to 70. Lameness, response to joint flexion, synovial effusion, gross and histologic joint assessments, and serum and synovial fluid biochemical data were compared between treatment groups to identify effects of treatment.
Results—Osteochondral fragmentation induced significant increases in various variables indicative of joint pain and disease. Treatment with ASU extracts did not have an effect on signs of pain or lameness; however, there was a significant reduction in severity of articular cartilage erosion and synovial hemorrhage (assessed grossly) and significant increase in articular cartilage glycosaminoglycan synthesis, compared with placebo-treated horses.
Conclusions and Clinical Relevance—Although treatment with ASU extracts did not decrease clinical signs of pain in horses with experimentally induced osteoarthritis, there did appear to be a disease-modifying effect of treatment, compared with findings in placebotreated horses. These objective data support the use of ASU extracts as a disease-modifying treatment for management of osteoarthritis in horses.
Objective—To determine the feasibility of the use of Fourier-transform infrared (FTIR) spectroscopy within the midinfrared range to differentiate synovial fluid samples of joints with osteochondrosis from those of control samples.
Animals—33 horses with osteochondrosis of the tarsocrural joint and 31 horses free of tarsocrural joint disease.
Procedures—FTIR spectroscopy of synovial fluid was used. Sixty-four synovial fluid samples from the tarsocrural joint were collected. Of these, 33 samples were from horses with radiographic evidence of osteochondrosis of the tarsocrural joint and 31 from control joints. Disease-associated features within infrared spectra of synovial fluid were statistically selected for spectral classification, and the variables identified were used in a classification model. Linear discriminant analysis and leave-one-out cross-validation were used to develop a classifier to identify joints with osteochondrosis.
Results—12 significant subregions were identified that met the selection criteria. The stepwise discriminant procedure resulted in the final selection of 6 optimal regions that most contributed to the discriminatory power of the classification algorithm. Infrared spectra derived from synovial fluid of joints with osteochondrosis were differentiated from the control samples with accuracy of 77% (81% specificity and 73% sensitivity).
Conclusions and Clinical Relevance—The disease-associated characteristics of infrared spectra of synovial fluid from joints with osteochondrosis may be exploited via appropriate feature selection and classification algorithms to differentiate joints with osteochondrosis from those of control joints. Further study with larger sample size including age-, breed-, and sex-matched control horses would further validate the clinical value of infrared spectroscopy for the diagnosis of osteochondrosis in horses.
Objective—To determine the effects of matrix metalloproteinase (MMP)-13, compared with interleukin (IL)-1α, on cartilage matrix molecule gene expression in a coculture system of equine cartilage explants and synoviocytes.
Sample Population—Articular cartilage and synovium specimens harvested from femoropatellar joints of 4 horses, aged 3 to 5 years.
Procedures—Synoviocytes were isolated and cocultured with cartilage explants. Cultures were treated with human recombinant MMP-13 (1, 25, or 100 ng/mL) or IL-1α (0.01, 0.1, 1.0, or 10 ng/mL) for 96 hours, with medium exchange at 48 hours. Cartilage extracts and media were analyzed for glycosaminoglycan (GAG) content, and results were adjusted to cartilage DNA content. Quantitative PCR was performed on mRNA from cartilage (MMP-3, MMP-13, aggrecan, and collagen type IIB [COL2A1]) and synoviocytes (MMP-3 and MMP-13), and results were adjusted to 18S ribosomal subunit mRNA expression. Treatments were performed in triplicate, and the experiment was repeated 4 times.
Results—Cultures treated with MMP-13 or IL-1α had increased media GAG concentration at 48 and 96 hours. Aggrecan and COL2A1 mRNA expression were increased by application of MMP-13 or IL-1α. Gene expression of the catabolic mediator, MMP-3, in cartilage and synoviocytes was increased in cultures treated with MMP-13 or IL-1α. Expression of MMP-13 mRNA in cartilage was increased by IL-1α, but decreased in synoviocytes by MMP-13 treatment.
Conclusions and Clinical Relevance—Results support the use of recombinant MMP-13 in a coculture system of synoviocytes and cartilage explants for the study of osteoarthritis.