Laryngeal advancement surgery improves swallowing function in a reversible equine dysphagia model.

REASONS FOR PERFORMING STUDY: Pharyngeal dysphagia is a debilitating, sometimes fatal condition in horses, with multiple aetiologies. The pathophysiology is complex and not fully understood. Treatment is largely supportive. Laryngeal advancement surgery may diminish symptoms of dysphagia and improve swallowing in affected horses. OBJECTIVES: 1) to induce reversible moderate and marked pharyngeal dysphagia by regional anaesthesia of branches of the glossopharyngeal (IX), vagus (X) and hypoglossal (XII) nerves; 2) to characterise the dysphagia produced by each model; and 3) to determine whether laryngeal advancement surgery improves swallowing in these models. STUDY DESIGN: Experimental design using 6 adult horses. METHODS: Two dysphagia models were produced by blocking IX, the pharyngeal branch of X and XII unilaterally (moderate model) and only the pharyngeal branch of X bilaterally (marked model) within the guttural pouches. Both models were performed on each horse before and after surgery in order to assess the effectiveness of the surgical procedure as a potential treatment for pharyngeal dysphagia. Dysphagia was scored by partly blinded observers on a scale of 0-12 based on observations of eating (nonblinded), endoscopic examinations and fluoroscopic swallowing (blinded), where 0 = normal swallow and 12 = severe dysphagia with tracheal aspiration. Data were analysed by 3-factor ANOVA, with significance taken as P<0.05. RESULTS: Dysphagia models were reversible, and horses swallowed normally within 3 h of model induction. The marked dysphagia model impaired movement of feed from the base of the tongue to the oesophagus and caused severe airway contamination. The average dysphagia score (mean ± s.d.) for the marked dysphagia model was 10.6 ± 1.1 before surgery and 6.1 ± 4.3 after surgery (P = 0.007). Laryngeal advancement surgery did not significantly improve the dysphagia scores in the moderate model (P = 0.5). CONCLUSIONS: Laryngeal advancement surgery may improve swallowing and reduce aspiration in horses affected with diseases that cause pharyngeal dysphagia.

Comparison of conventional and alternative arthroscopic approaches to the palmar/plantar pouch of the equine distal interphalangeal joint.

REASONS FOR PERFORMING THE STUDY: The conventional arthroscopic approach to the palmar/plantar aspect of the distal interphalangeal joint (DIPJ) may result in the inadvertent penetration of the digital flexor tendon sheath (DFTS) and the navicular bursa (NB). This iatrogenic communication would be undesirable subsequent to arthroscopic lavage of a septic DIPJ. HYPOTHESIS: A lateral/medial approach to the palmar/plantar aspect of the DIPJ will result in a significantly lower rate of inadvertent penetration of the DFTS and NB, whilst still providing adequate intra-articular evaluation. METHODS: The conventional palmar/plantar approach or a novel lateral/medial approach to the DIPJ was performed on cadaver fore- and hindlimbs (30 limbs/approach). Subsequently, India ink was injected into the dorsal pouch of the DIPJ, and the DFTS (n = 60) and NB (n = 20) were examined for the presence/absence of ink. In addition, observations of the number of attempts made to access the joint, evidence of iatrogenic intra-articular trauma and occurrence of incomplete visualisation of the palmar/plantar pouch were recorded. RESULTS: With the conventional approach, DFTS penetration was noted in 18/30 (60%) of the limbs, compared to 1/30 (3.3%) with the lateral/medial approach (P≤0.001). NB penetration was seen in 5/10 limbs with the palmar/plantar approach compared to 0/10 with the lateral/medial approach (P = 0.01). No significant differences were found between the approaches in the number of attempts made to access the joint, the incidence of iatrogenic intra-articular trauma, or the occurrence of incomplete visibility of the palmar/plantar pouch. CONCLUSIONS: The novel lateral/medial approach to the DIPJ significantly decreases the risk of inadvertent penetration of the DFTS and NB. POTENTIAL RELEVANCE: The novel lateral/medial approach to the DIPJ is an effective technique to gain access to the palmar/plantar pouches, and is particularly advantageous for arthroscopic lavage of a septic DIPJ.

Retrospective study of 108 foals with septic osteomyelitis.

OBJECTIVE: To determine the clinical characteristics, short-term outcome and future athletic performance of foals with septic osteomyelitis. DESIGN: Retrospective clinical study of 108 Thoroughbred foals with radiographic evidence of bone infection that were presented at the Scone Veterinary Hospital between August 1995 and December 2001. Medical records were reviewed and information concerning signalment, the clinical, laboratory and radiographic findings, treatment and outcome was obtained. Racing records were obtained and evaluated for surviving foals that had reached racing age. RESULTS: Mean age of foals at initial evaluation was 39 days (range 1-180 days); 21 foals had multiple radiographic bone lesions (19.4%), and 76 had concurrent septic arthritis (70.4%). The most frequently affected bones were the femur, tibia and distal phalanx. In total, 87 foals were discharged from the hospital (80.6%), 79 survived long-term to reach racing age and 52 raced (65.8%). Overall, 48% (52/108) of the foals treated for osteomyelitis raced. Foals less than 30 days of age at the time of diagnosis, critically ill foals and those with multiple bones or joints affected were significantly less likely to be discharged from hospital. Multiple septic joints, but not multiple bone involvement, had an unfavourable prognosis for racing. CONCLUSIONS: The prognosis for survival of foals with septic osteomyelitis or osteitis is favourable. Multiple bone or joint involvement is an important short-term prognostic indicator; however, the involvement of multiple joints, but not multiple infected bones, is associated with an unfavourable prognosis for racing.

Retrospective multicentre study of methicillin-resistant Staphylococcus aureus infections in 115 horses.

REASONS FOR PERFORMING STUDY: Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging veterinary and zoonotic pathogen, associated with increasing reports of disease in horses. OBJECTIVES: To provide an overview of the characteristics of clinical MRSA infections in horses. METHODS: A retrospective case study was performed on 115 horses admitted to 6 participating veterinary teaching hospitals in Canada and the United States between 2000 and 2006, and diagnosed with clinical MRSA infection. Descriptive statistics, univariate and multivariable analyses for community- (CA) vs. hospital-associated (HA) MRSA infections, and survival vs. nonsurvival at discharge were performed. RESULTS: The age range of MRSA-infected horses was zero (born in hospital) to 31 years. HA (58/114, 50.9%) and CA infections (56/114, 49.1%) were equally common. Infection of surgical incisions was most frequently reported (44/115, 38.0%). Overall 93/111 (83.8%) cases survived to discharge. Previous hospitalisation and treatment with gentamicin were associated significantly with CA-MRSA, whereas infected incision sites were associated significantly with HA-MRSA. Factors significantly associated with nonsurvival included i.v. catheterisation, CA-MRSA infection and dissemination of infection to other body sites. CONCLUSIONS: Equine MRSA infections have a broad range of clinical presentations, appear to be primarily opportunistic and the overall prognosis for survival to discharge is good. POTENTIAL RELEVANCE: These results should help direct future research with regard to investigation of risk factors for equine MRSA infection in community and hospital populations.

Glucosamine and chondroitin sulfate regulate gene expression and synthesis of nitric oxide and prostaglandin E(2) in articular cartilage explants.

OBJECTIVE: Glucosamine (GLN) and chondroitin sulfate (CS) are widely used to alleviate symptoms of osteoarthritis (OA). However, the mechanism(s) of action of these nutraceuticals remains unresolved. In the present study, we determined the effect of physiologically relevant concentrations of GLN and CS on gene expression and synthesis of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in cytokine-stimulated articular cartilage explants. METHODS: Using bovine articular cartilage explants in culture stimulated with IL-1, the effects of physiologically relevant concentrations of GLN and CS on gene expression of inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGEs1) were assessed with quantitative real-time polymerase chain reaction (Q-RT-PCR). The production of NO and PGE(2) was also quantified. RESULTS: CS and the GLN and CS combination at concentrations attainable in the blood down-regulated IL-1 induced mRNA expression of iNOS at 24 and 48 h post-culture. Up-regulated iNOS expression at 24h by IL-1 was also suppressed by GLN. GLN and CS transiently repressed the cytokine-stimulated mPGEs1 transcript. Synthesis of NO was reduced with CS alone and the combination after 24h of culture. Repression of COX-2 transcripts by GLN and CS was accompanied by concomitant reduction in PGE(2). CONCLUSION: Our results indicate that physiologically relevant concentrations of GLN and CS can regulate gene expression and synthesis of NO and PGE(2), providing a plausible explanation for their purported anti-inflammatory properties.

Effect of glucosamine on interleukin-1-conditioned articular cartilage.

Glucosamine inhibits recombinant human interleukin-1 stimulated cartilage degradation in equine cartilage explants. Recently, recombinant equine interleukin-1 has been cloned and purified. Therefore, the objective of this study was to characterise the effects of glucosamine on indices of cartilage degradation in recombinant equine IL-1beta-stimulated equine articular cartilage explants. Cartilage discs were harvested from the weight-bearing region of the articular surface of the antebrachiocarpal and middle carpal joints of horses (age 2-8 years) and cultured under standard conditions. Explants were exposed to recombinant equine interleukin-1beta (reIL-1beta) on Days 1-4 in the presence or absence of glucosamine (0.25, 2.5 or 25 mg/ml), with appropriate controls. Nitric oxide, prostaglandin E2, sulphated proteoglycan, stromelysin and gelatinase/collagenase activity released into conditioned media and total tissue proteoglycan content were measured as indicators of cartilage catabolism. Glucosamine inhibited cartilage catabolic responses in a dose dependent manner that was statistically significant at a dose of 0.25 mg/ml for stromelysin activity and 2.5 mg/ml for collagenase/gelatinase activity. At 25 mg/ml glucosamine also prevented IL-1beta-induced increases in nitric oxide production, prostaglandin E2 and proteoglycan release to media. Glucosamine prevents equine articular cartilage degradation experimentally induced by reIL-1beta in vitro. These data provide further support for the use of glucosamine in treatment or prevention of cartilage loss in athletic horses.

Recombinant equine interleukin-1beta induces putative mediators of articular cartilage degradation in equine chondrocytes.

Interleukin-1 is considered a central mediator of cartilage loss in osteoarthritis in several species, however an equine recombinant form of this cytokine is not readily available for in vitro use in equine osteoarthritis research. Equine recombinant interleukin-1beta was cloned and expressed and its effects on the expression and activity of selected chondrocytic proteins implicated in cartilage matrix degradation were characterized. Reverse transcriptase polymerase chain reaction methods were used to amplify the entire coding region of the equine IL-1beta mRNA, which was cloned into an expression vector, expressed in E. coli, and purified using a Ni2+ chromatographic method. The effects of the recombinant peptide on chondrocyte gene expression were determined by Northern blotting using RNA from equine chondrocyte cultures hybridized to probes for matrix metalloproteinases (MMP 1, MMP 3, MMP 13), tissue inhibitor of matrix metalloproteinases 1 (TIMP 1) and cyclooxygenase 2 (COX 2). Effects on selected mediators of cartilage degradation (nitrite concentrations and MMP activity) were determined using conditioned medium from reIL-1beta-treated equine cartilage explant cultures. A recombinant peptide of approximately 21 kd was obtained. Northern blotting analyses revealed a marked up-regulation of expression of all MMPs, TIMP 1, and COX 2 in mRNA from treated chondrocytes. Furthermore, cartilage explants exposed to reIL-1beta had augmented collagenase/gelatinase and stromelysin activities as well as increased concentration of nitrite in conditioned media. The development of a biologically active, species-specific IL-1beta provides a valuable tool in the study of osteoarthritis pathophysiology and its treatment in horses.

Inducible nitric oxide expression in equine articular chondrocytes: effects of antiinflammatory compounds.

OBJECTIVE: To determine the effects of recombinant equine IL-1beta and a number of antiinflammatory compounds on the expression and activity of inducible nitric oxide synthase (iNOS) in cultured equine chondrocytes. DESIGN: RT-PCR methods were used to amplify a portion of the equine iNOS message to prepare an RNA probe. Northern blot analysis was used to quantify the expression of iNOS in first passage cultures of equine articular chondrocytes propagated in the presence or absence of recombinant equine interleukin-1beta (reIL-1beta), dexamethasone (DEX), polysulfated glycosaminoglycan (PSGAG), hyaluronan (HA), and phenylbutazone (PBZ), each at concentrations of 10 and 100 microg/ml. Nitrite concentrations in conditioned media of similarly treated cells were used to quantify iNOS activity. RESULTS: Recombinant equine IL-1beta increased the expression of iNOS in a dose-dependent manner. This result was paralleled by an increased concentration of nitrite in the culture media of reIL-1beta-treated cells. DEX and PSGAG significantly reduced iNOS gene expression and media supernatant nitrite concentrations in cytokine-stimulated cultures. HA and PBZ had no consistent effect on the expression of iNOS and did not significantly influence nitrite content of conditioned media. CONCLUSIONS: NO is considered an important mediator in the pathophysiologic processes of arthritis and an inducible NOS is expressed by equine chondrocytes. Pre-translational regulation of the iNOS gene by DEX and PSGAG appears to contribute to the cartilage-sparing properties of these compounds.

The effects of glucosamine derivatives on equine articular cartilage degradation in explant culture.

OBJECTIVE: To determine whether glucosamine-3-sulfate, glucose-3-sulfate (control) and N-acetyl glucosamine inhibit experimentally induced degradation of equine articular cartilage explants similar to glucosamine HCl. DESIGN: Articular cartilage was obtained from the antebrachio-carpal and middle joints of horses (2-8 years old) killed for reasons unrelated to lameness. Cartilage discs were harvested from the weight-bearing region of the articular surface and cultured. Media were exchanged daily and the recovered media stored at 4 degrees C. On days 1 and 2 lipopolysaccharide (LPS, 10 microg/ml) was added to induce cartilage degradation. To evaluate the effects of different sources of glucosamine (on an equal molar basis), varying concentrations of glucosamine HCl (0.25, 2.5, or 25 mg/ml), glucosamine-3-sulfate (0.304, 3.04, or 30.4 mg/ml), or N-acetyl-glucosamine (0.256, 2.56, or 25.6 mg/ml) were added to the cultures. The glucose-3-sulfate control was added at 0.3075, 3.075 or 30.75 mg/ml. Nitric oxide and proteoglycan released into conditioned media and tissue proteoglycan synthesis and total tissue PG content were measured as indicators of cartilage metabolism. RESULTS: Glucosamine-3-sulfate consistently inhibited cartilage degradation in a manner similar to glucosamine HCl, while the effects of N-acetyl-glucosamine were highly variable and did not inhibit cartilage degradation. Glucose-3-sulfate did not inhibit cartilage degradation. CONCLUSION: Our results indicate that glucosamine sulfate also has the potential to prevent or reduce articular cartilage degradation similar to glucosamine HCl in vitro. The amine group at the carbon-2 position appears important for the effectiveness of the glucosamine derivative. The therapeutic value of N-acetyl-glucosamine remains questionable.

Glucosamine HCl reduces equine articular cartilage degradation in explant culture.

Objective To determine whether glucosamine inhibits experimentally induced degradation of equine articular cartilage explants. Methods Articular cartilage was obtained from the antebrachio-carpal and middle joints of horses (2-8 years old) killed for reasons unrelated to lameness. Cartilage discs were harvested from the weight-bearing region of the articular surface and cultured. Media were exchanged daily and the recovered media stored at 4 degrees C. Explants were maintained in basal media 2 days prior to the start of four treatment days. On days 1-4 lipopolysaccharide (LPS, 10 microg/ml) or recombinant human interleukin-1 (rhIL-1, 50 ng/ml) were added to induce cartilage degradation. To test the potential protective effects of glucosamine, the compound was added in three concentrations (0.25, 2.5, or 25 mg/ml) and treatments were performed in triplicate. Controls included wells without LPS, rhIL-1beta, or glucosamine. Nitric oxide, proteoglycan and matrix metalloproteinases (MMP) released into conditioned media and tissue proteoglycan synthesis were measured as indicators of cartilage metabolism. Results Maximal nitric oxide production, proteoglycan release, and MMP activity were detected 1 day after the addition of LPS or rhIL-1beta to the media. The addition of 25 mg/ml of glucosamine prevented the increase in nitric oxide production, proteoglycan release and MMP activity induced by LPS or rhIL-1. Conclusions These data indicate that glucosamine can prevent experimentally induced cartilage degradation in vitro.

Effect of longeing and glucosamine supplementation on serum markers of bone and joint metabolism in yearling quarter horses.

The effect of longeing and glucosamine supplementation on known biological markers of joint disease was studied in yearling quarter horses. Twenty-one yearling quarter horses were randomly assigned to one of 4 treatments: 1) longeing (longeing 20 min daily) supplement control (LN); 2) longeing/glucosamine (LG); 3) walking (mechanical walker for 120 min daily (WN)); and 4) walking/glucosamine (WG). Oral glucosamine was administered at 5.5 g b.i.d. weeks 1-4, 3.5 g b.i.d. during weeks 5-6, and 2.0 g b.i.d. during weeks 7-8. Serum was obtained weekly for 8 wk and analyzed for keratan sulfate and osteocalcin concentrations. Walked horses receiving glucosamine showed slight elevation in serum keratan sulfate compared to controls (P = 0.04). Glucosamine or longeing exercise had no significant effect (6 > or = 0.08) on serum osteocalcin concentrations. Under these conditions, longeing and/or glucosamine supplementation did not significantly alter serum concentrations of keratan sulfate or osteocalcin.

Factors influencing recovery from and duration of lameness in Michigan (USA) horses.

The objective of this study was to identify factors that may affect recovery from and duration of a case of lameness in a stratified random sample of Michigan horses. This was done using data from Phase-II of the Michigan equine monitoring system (MEMS Phase-II), the equine health-monitoring study [Kaneene et al., Prev. Vet. Med. 29 (1997b) 277-292; Ross and Kaneene, Prev. Vet. Med. 28 (1996a) 209-224; Ross and Kaneene, Prev. Vet. Med. 29 (1996b) 59-75; Ross et al., Am. J. Vet. Res. 59 (1997) 23-29]. In this study, statistical modelling was conducted to evaluate risk factors affecting recovery from and duration of lameness using multivariable logistic regression and Cox's proportional hazards regression, respectively. Of 357 incident lameness cases reported during MEMS Phase-II, 280 (78.6%) were reported to have recovered. The median duration of a lameness case was 18 days (1st quartile (Q): 1, maximum (Max): 360). A total of 296 of 357 (82.9%) incident lameness cases received some type of treatment. Of 619 total treatments used, 329 (53.2%) were administered, conducted or applied by a veterinarian. Horses experiencing other types of lameness were less likely to recover than those experiencing hoof lameness (odds ratio (OR) = 0.48; 95% CI: 0.25, 0.93). Horses that had participated in exercise-related activities during the study period and prior to the lameness were more likely to recover (OR = 1.91; 95% CI: 1.05, 3.50). Treatment of the lameness was associated with an increased likelihood of recovery (OR = 1.82; 95% CI: 0.97, 3.45). Cases with a veterinarian involved in the diagnosis were associated with a decreased risk of recovery (OR = 0.48; 95% CI: 0.27, 0.84) and a longer duration lameness (HR = 0.58; 95% CI: 0.45, 0.73)--which might indicate that these cases were more complex or severe. Although cases treated for lameness were more likely to recover (OR = 1.82; 95% CI: 1.05, 3.50), treatment was not associated with lameness duration (HR = 0.58; 95% CI: 0.45, 0.73).

Methicillin-resistant Staphylococcus aureus outbreak in a veterinary teaching hospital: potential human-to-animal transmission.

During a 13-month period, 11 equine patients visiting a veterinary teaching hospital for various diagnostic and surgical procedures developed postprocedural infections from which methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA) strains were isolated. The S. aureus isolates were identified by conventional methods that included Gram staining, tests for colonial morphology, tests for clumping factor, and tests for coagulase and urease activities and were also tested with the API STAPH IDENT system. Antimicrobial susceptibility tests were performed by the disk diffusion method. The biochemical profile and antibiogram of each isolate suggested that the isolates may have come from a common source. Because MRSA strains are very uncommon animal isolates but are rather common human isolates, a nasal swab specimen for culture was collected voluntarily from five persons associated with equine surgery and recovery in an attempt to identify a possible source of the organisms. MRSA strains were isolated from three of the five people, with one person found to be colonized with two biotypes of MRSA. The MRSA isolates from the people appeared to be identical to the isolates from horses. Further study of the isolates included SmaI and EagI macrorestriction analysis by pulsed-field gel electrophoresis conducted in two different laboratories. The results indicated that both the equine and human isolates were members of a very closely related group which appear to have originated from a common source. On the basis of the pattern associated with the infection, it is speculated that the members of the Veterinary Teaching Hospital staff were the primary source of the infection, although the specific mode of transmission is unclear.

Osteochondritis dessicans and subchondral cystic lesions in draft horses: a retrospective study.

The clinical features, radiographic findings, treatment, and outcome in 51 draft horses with osteochondritis dessicans (OCD) or subchondral cystic lesions (SC) are reported. Clydesdale and Percheron were the most commonly affected breeds, and affected animals represented only 5% of the hospital population of draft horses. Horses were most frequently affected in the tibiotarsal joints and 73% (24 of 33 cases) of the horses with tibiotarsal effusion were affected bilaterally. Osteochondritis dessicans of the distal intermediate ridge was the most common lesion found in the tibiotarsal joint. The stifle was also frequently affected; 87% (13 of 15 cases) of horses with femoropatellar OCD only were lame, and lesions were most commonly located on the lateral trochlear ridge. Sixteen cases were managed conservatively, 30 received surgery, and 5 were euthanized. Lameness, effusion, or both clinical signs resolved in more than 50% of surgically treated cases, but clinical signs improved in 30% of conservatively-managed cases.

Influence of exogenous hyaluronan on synthesis of hyaluronan and collagenase by equine synoviocytes.

OBJECTIVE: To evaluate the influence of exogenous hyaluronan (HA) on in vitro synthesis of HA and collagenase by equine synoviocytes from normal and inflamed joints. ANIMALS: 9 adult horses. PROCEDURE: Synoviocytes for culture were taken from the middle carpal joint of 3 horses with normal joints (control) and 6 horses with osteochondral fractures (principal). Synoviocytes were propagated in monolayer cultures and were incubated with 3 commercial HA products at concentrations of 0, 200, 400, and 1,500 micrograms/ml. Newly synthesized HA was radiolabeled with [3H]glucosamine and quantified by cetylpyridinium chloride precipitation and liquid scintillation counting. The hydrodynamic size of radioactive HA was determined by high-performance liquid chromatography, and collagenase activity was evaluated by use of a quantitative radioactive collagen film assay. RESULTS: Exogenous HA influenced neither the rate of synthesis nor the hydrodynamic size of the newly produced HA by control or principal cell cultures. Culture supernatants from abnormal synovium, exposed to 400 and 1,500 micrograms of exogenous HA/ml, contained significantly more collagenase activity than did those exposed to lower concentrations. CONCLUSION: Although HA is thought to have beneficial effects in equine arthropathies, the principal mechanisms of action of HA do not appear to be stimulation of synthesis of HA of augmented molecular weight or marked inhibition of collagenase synthesis.

In vivo suppression of early experimental osteoarthritis by interleukin-1 receptor antagonist using gene therapy.

OBJECTIVE: This study explored the therapeutic effect of interleukin-1 receptor antagonist (IL-1Ra), administered by gene transfer, on the progression of osteoarthritic (OA) lesions in an experimental dog model. METHODS: Seventeen mature mongrel dogs were divided into 3 groups. Group 1 (n = 7) had an anterior cruciate ligament (ACL) section of the right knee through a stab wound incision. Groups 2 and 3 (n = 5 per group), had an ACL section of the right knee and partial synovectomy of the left knee. Each dog's synovium was subjected to enzymatic digestion, and the synovial fibroblasts were propagated in monolayer culture. Synovial cells from each dog were transduced in vitro using the retrovirus MFG with either the Escherichia coli beta-galactosidase (lac Z) gene (group 2) or the human IL-1Ra gene (group 3). Two days after surgery, the dogs received intraarticular injections as follows: group 1 phosphate buffered saline (PBS) (2 ml); group 2 autologous cells (60 x 10(6) cells/2 ml of PBS) transduced with the lac Z gene; group 3 autologous cells transduced with the IL-1Ra gene. Synovial fluid was aspirated at 2 weeks and 4 weeks. All dogs were euthanized at 4 weeks postsurgery. The right knees were dissected, and lesions were scored for macroscopic and microscopic changes. Synovial explants were dissected and representative specimens were used for histology or were cultured for 48 hours. The levels of IL-1Ra in synovial fluid and synovial explant conditioned medium were measured by specific enzyme-linked immunosorbent assay. RESULTS: The level of IL-1Ra in synovial fluid of group 3 was 202.8 +/- 131.5 ng/ml (mean +/- SEM) at 2 weeks and 2.8 +/- 2.2 ng/ml at 4 weeks after surgery. Membrane explants isolated from dogs that received synovial cells transduced with the IL-1Ra gene (group 3) actively produced IL-1Ra (4.0 +/- 2.0 ng/gm of tissue wet weight). The severity of OA cartilage lesions was similar in groups 1 and 2. In contrast, group 3 dogs had a marked reduction in macroscopic lesion severity on the tibial plateaus (P < 0.01 for grade; P < 0.04 for size) and femoral condyles. Moreover, the histologic lesion severity was decreased on both plateaus (P < 0.06) and condyles. CONCLUSION: This study showed that a local increase in IL-1Ra production in OA knee joints by intraarticular injection of transduced synovial cells can reduce the progression of experimentally induced lesions.

The therapeutic effects of tenidap in canine experimental osteoarthritis: relationship with biochemical markers.

OBJECTIVE: To define the dose-response relationship of the therapeutic effects of tenidap in experimental osteoarthritis (OA) and relate this to the effects on interleukin 1 (IL-1) and metalloprotease activity. METHODS: The anterior cruciate ligament of the right knee joints of 22 mongrel dogs were sectioned (ACLS) through a stab wound. Seven dogs received no treatment, 5 were treated with oral omeprazole (20 mg/day), another 5 were treated with oral tenidap (1.5 mg/kg bid) plus omeprazole (20 mg/day), and 5 received tenidap (0.5 mg/kg bid) plus omeprazole (20 mg/day). The dogs received medication for 8 weeks beginning 4 weeks after surgery. All dogs were killed 12 weeks after surgery, except for those in the first group, which were sacrificed at 4 weeks. Lesions were evaluated macroscopically for the incidence and size of osteophytes and the area and grade of cartilage erosions on the condyles and plateaus, along with histologic evaluation of the severity of the cartilage lesions and synovial inflammation. Stromelysin, collagenase, and gelatinase activities were measured in cartilage and synovial membrane. Also, the level of IL-1 activity was measured in the synovial fluid. RESULTS: Dogs treated with tenidap at both 1.5 and 0.5 mg/kg bid exhibited a reduction in the size of osteophytes (2.25 +/- 0.30 mm, 1.70 +/- 0.65 mm, respectively) compared to the 12 weeks OA group (3.55 +/- 0.94 mm). Tenidap also significantly decreased the size and/or grade or cartilage macroscopic lesions on both condyles and plateaus. This reduction was more pronounced in dogs treated with the higher drug dose. The histological severity of cartilage lesions on femoral condyles was reduced for both tenidap doses used and significance (p < 0.04) reached for the 1.5 mg/kg bid tenidap treated dogs. Tenidap markedly and significantly reduced the level of metalloprotease activity for all 3 enzymes tested in synovial membrane (stromelysin, p < 0.03; collagenase, p < 0.02; gelatinase, p < 0.03) and in cartilage (stromelysin, p < 0.02; collagenase, p < 0.02; gelatinase, p < 0.03) with greater reduction, in general, in dogs treated with the higher dose of tenidap. IL-1 activity was significantly reduced (p < 0.02) only in animals treated with tenidap at 1.5 mg/kg bid. CONCLUSION: This study confirms that tenidap is an effective anti-osteoarthritic drug in this ACLS model where therapy was begun 4 weeks after surgery. We have defined doses that gave graded therapeutic effects, and under these conditions the effectiveness coincided with the suppression of IL-1 and metalloprotease activity, processes known to play a major role in the pathophysiology of OA lesions.

Effects of tenidap on the progression of osteoarthritic lesions in a canine experimental model. Suppression of metalloprotease and interleukin-1 activity.

OBJECTIVE: To study, in vivo, the therapeutic effectiveness of tenidap, an antirheumatic drug, on the progression of lesions in an experimental osteoarthritis (OA) dog model. The action of tenidap on the activity and expression of metalloproteases in cartilage, as well as on the bioactivity of interleukin-1 (IL-1) in synovial fluid, was determined. METHODS: The anterior cruciate ligament of the right stifle joint of 20 mongrel dogs was sectioned through a stab wound. Dogs were divided into 3 groups: group I (n = 7) received no treatment, group II (n = 6) was treated with oral omeprazole (20 mg/day), and group III (n = 7) received oral omeprazole (20 mg/day) and a therapeutic dosage of oral tenidap (3 mg/kg twice daily). Four weeks following surgery, the untreated dogs (group I) were killed, and drug treatments were begun for the other dogs (groups II and III). These dogs received medications for 8 weeks (weeks 4-12) and then were killed. Evaluations were made of the incidence and size of osteophytes as well as of the size and grade of cartilage erosions on both the condyles and plateaus. Histologic examination of the severity of the cartilage lesions and synovial inflammation was also performed. Activity levels of collagenase, stromelysin, and gelatinase as well as collagenase-1, collagenase-3, and stromelysin-1 messenger RNA were determined in the cartilage. The level of IL-1 activity in the synovial fluid was also measured. RESULTS: Among the dogs with OA, lesions were more severe at 12 weeks than at 4 weeks. Group III (tenidap-treated) dogs had a slightly reduced incidence of osteophytes compared with the group II (12-week OA) dogs (71% versus 100%), and the size of the osteophytes was significantly diminished (mean +/- SEM 1.75 +/- 0.69 mm versus 4.38 +/- 0.64 mm). Macroscopically, tenidap decreased the size (condyles 6.00 +/- 2.18 mm2 versus 21.08 +/- 6.70 mm2, plateaus 15.50 +/- 4.77 mm2 versus 35.0 +/- 3.64 mm2) and the grade (condyles 0.57 +/- 0.20 versus 1.17 +/- 0.21, plateaus 1.07 +/- 0.22 versus 2.00 +/- 0.25) of the cartilage lesions compared with the 12-week OA dogs. At the histologic level, the severity of cartilage lesions was also decreased in the tenidap-treated dogs versus the 12-week OA dogs, both on the condyles (3.43 +/- 0.54 versus 5.55 +/- 0.38) and on the plateaus (3.39 +/- 0.35 versus 5.54 +/- 0.60). All 3 OA groups showed a significant and similar level of synovial inflammation. Tenidap markedly decreased collagenase, stromelysin, and gelatinase activity, as well as the level of expression of collagenase-3 in the cartilage. Interestingly, the activity level of IL-1 in synovial fluid was also significantly reduced in the tenidap-treated dogs. CONCLUSION: Tenidap markedly reduced the severity of OA lesions, indicating the effect of this drug in decreasing the progression of disease. It appears that the drug acts by reducing the activity and/or expression of metalloproteases in cartilage, a process known to play a major role in the pathophysiology of OA lesions. This effect could be mediated by the suppressive effect of tenidap on IL-1 activity.

Results of a survey of equine practitioners on the use and perceived efficacy of polysulfated glycosaminoglycan.

OBJECTIVE: To determine the patterns of use and perceived efficacy of polysulfated glycosaminoglycan (PSGAG) for the treatment of degenerative joint disease in horses. DESIGN: Cross-sectional mail survey. SAMPLE POPULATION: 1,522 equine practitioners. PROCEDURE: Information was obtained on frequency and route of administration of PSGAG for the treatment of each of 4 forms of degenerative joint disease, the efficacy of PSGAG, and its efficacy compared with that of sodium hyaluronate. Data were analyzed by nonparametric and multivariate regression methods. RESULTS: Response rate was 40.5%. Of practitioners responding, 26% were classified as having a special interest in lameness and 74% as general practitioners. Use of PSGAG was reported by 90.5% of all practitioners, but lameness practitioners used PSGAG more frequently than general practitioners. Use of PSGAG also was significantly more common among practitioners involved predominately with racing. Thoroughbreds, Standardbreds, or show horses. Use of PSGAG was reported to be moderately effective in the treatment of the 4 joint disease conditions. Practitioners treating Thoroughbred racehorses gave highest efficacy scores, and pleasure horse practitioners gave lowest efficacy scores. Use of PSGAG was considered more effective than sodium hyaluronate for the treatment of subacute degenerative joint disease and less effective for idiopathic joint effusion and acute synovitis. CLINICAL IMPLICATIONS: Use of PSGAG is regarded as moderately effective overall and is considered most useful in the treatment of subacute degenerative joint disease. The efficacy of PSGAG for incipient and chronic forms of degenerative disease is considered comparable to that of sodium hyaluronate.

Modulation of matrix metalloprotease 13 (collagenase 3) gene expression in equine chondrocytes by interleukin 1 and corticosteroids.

OBJECTIVE: To determine whether matrix metalloprotease 13 (MMP-13; collagenase 3) is produced by equine chondrocytes and to investigate modulation of its expression by recombinant human interleukin 1 beta (rhIL-1 beta) and corticosteroids. PROCEDURE: Equine chondrocytes in monolayer culture were stimulated with rhIL-1 beta. Total RNA was extracted, purified, and reverse transcribed into DNA. Using appropriate primers, a putative MMP-13 fragment was amplified by polymerase chain reaction, and cloned into a bacterial vector. The resultant fragment was purified and sequenced, then was used to prepare a digoxigenin-labeled cRNA probe. Monolayer cultures of first-passage chondrocytes were treated with rhIL-1 beta in the presence or absence of dexamethasone (10(-6)M) or methylprednisolone acetate (10(-9)M to 10(-5)M), in addition to positive and negative controls. Cellular RNA was extracted and resolved on agarose gels and subjected to northern blot analysis, using the equine MMP-13 probe. RESULTS: Reverse transcriptase-polymerase chain reaction enabled isolation of a 0.6-kb fragment of equine MMP-13 cDNA that had 93% homology with the human MMP-13 cDNA sequence. rhIL-1 significantly stimulated MMP-13 expression in the chondrocytes. Methylprednisolone acetate inhibited the stimulatory effects of rhIL-1 in dose-dependent manner that was statistically significant at 10(-5)M. CONCLUSIONS: Novel information was gained on the existence of MMP-13 and its expression in equine chondrocytes, which suggests a possible role for this enzyme in matrix degradation in horses with arthritis.