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  • Author or Editor: C. Wayne McIlwraith x
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Abstract

Objective—To compare the mesenchymal stem cell (MSC) yield and chondrogenic and osteogenic differentiation from 5- and 50-mL bone marrow aspirates from horses.

Animals—Six 2- to 5-year-old mixed-breed horses.

Procedures—2 sequential 5-mL aspirates were drawn from 1 ilium or sternebra. A single 50-mL aspirate was drawn from the contralateral ilium, and 2 sequential 50-mL aspirates were drawn from a second sternebra. The MSC yield was determined through the culture expansion process. Chondrogenesis and osteogenesis were evaluated by means of conventional laboratory methods.

Results—The second of the 2 sequential 50-mL sternal aspirates yielded few to no MSCs. Independent of location, the highest density of MSCs was in the first of the 2 sequential 5-mL fractions, although with subsequent culture expansion, the overall yield was not significantly different between the first 5-mL and first 50-mL fractions. Independent of location, chondrogenesis and osteogenesis were not significantly different among fractions. Independent of fraction, the overall cell yield and chondrogenesis from the ilium were significantly higher than that from the sternum.

Conclusions and Clinical Relevance—This study failed to detect an additional benefit of 50-mL aspirates over 5-mL aspirates for culture-expanding MSCs for equine clinical applications. Chondrogenesis was highest for MSCs from ilial aspirates, although it is not known whether chondrogenesis is indicative of activation of other proposed pathways by which MSCs heal tissues.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess the clinical, biochemical, and histologic effects of extracorporeal shock wave therapy (ESWT) in the treatment of horses with experimentally induced osteoarthritis (OA).

Animals—Twenty-four 2- to 3-year-old horses without evidence of lameness.

Procedures—OA was induced arthroscopically in 1 middle carpal joint of each horse. Fourteen days after induction of OA, horses were treated with a sham ESWT probe (placebo; n = 8), polysulfated glycosaminoglycan (PSGAG) administered IM every 4 days for 28 days as a positive control treatment (8), or ESWT administered on days 14 and 28 with a focused shock wave unit (8). Evaluations included clinical assessments of degree of lameness every 2 weeks and weekly synovial fluid analyses. Horses were euthanized 70 days after induction of OA, and gross pathologic and histologic examinations of cartilage and synovial membrane specimens were performed at necropsy. A generalized linear mixed model was used to compare outcomes among treatment groups.

Results—No adverse treatment-related events were detected in any horse. The degree of lameness in horses treated with ESWT improved significantly, compared with the degree of lameness in placebo- or PSGAG-treated horses. No disease-modifying effects were evident in results for synovial fluid, synovial membranes, or cartilage from the ESWT- or PSGAG-treated horses.

Conclusions and Clinical Relevance—Although a disease-modifying effect of ESWT was not detected, the significant clinical effect of ESWT suggested that this modality should be considered for treatment of horses with OA in combination with another modality that does affect the disease process.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess clinical, biochemical, and histologic effects of polysulfated glycosaminoglycan (PSGAG) or sodium hyaluronan administered intra-articularly in treatment of horses with experimentally induced osteoarthritis.

Animals—24 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Eight horses received hyaluronan (20 mg) and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Eight horses received PSGAG (250 mg) and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Eight control horses received 2 mL of saline (0.9% NaCl) solution and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Clinical, radiographic, synovial fluid analysis, gross, histologic, histochemical, and biochemical findings were evaluated.

Results—No adverse treatment-related events were detected. Induced osteoarthritis caused a substantial change in lameness, response to flexion, joint effusion, and radiographic findings, and of these, synovial fluid effusion was reduced with PSGAG, compared with control horses. No changes in clinical signs were seen with PSGAG or hyaluronan, compared with control horses. Histologically, the degree of synovial membrane vascularity and subintimal fibrosis was significantly reduced with PSGAG treatment, compared with controls. Histologically, significantly less fibrillation was seen with hyaluronan treatment, compared with controls.

Conclusions and Clinical Relevance—Results indicated that PSGAG and hyaluronan had beneficial disease-modifying effects and are viable therapeutic options for osteoarthritis in horses.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the use of serum concentrations of biochemical markers of bone metabolism (osteocalcin [OC], bone-specific alkaline phosphatase [BS-ALP], and deoxypyridinoline [DPYR]) to compare healing in infected versus noninfected fractures and in fractures with normal repair versus delayed (nonunion) repair in rabbits.

Animals—32 female 9- to 10-month-old New Zealand White rabbits.

Procedure—A femoral fracture defect was made in each rabbit. Rabbits were assigned to the following groups: the bone morphogenetic-2 gene treatment group with either noninfected nonunion or infected (ie, inoculation of defects with Staphylococcus aureus) nonunion fractures or the luciferase (control) gene treatment group with either noninfected nonunion or infected nonunion fractures. Serum samples were obtained before surgery (time 0) and 4, 8, 12, and 16 weeks after surgery. Callus formation and lysis grades were evaluated radiographically at 16 weeks.

Results—Serum OC and BS-ALP concentrations decreased from time 0 at 4 weeks, peaked at 8 weeks, and then decreased. Serum DPYR concentration peaked at 4 weeks and then decreased, independent of gene treatment group or fracture infection status. Compared with rabbits with noninfected fractures, those with infected fractures had lower serum OC and BS-ALP concentrations at 4 weeks, higher serum OC concentrations at 16 weeks, and higher serum DPYR concentrations at 4, 8, and 16 weeks. Combined serum OC, BS-ALP, and DPYR concentrations provided an accuracy of 96% for prediction of fracture infection status at 4 weeks.

Conclusions and Clinical Relevance—Measurement of multiple serum biochemical markers of bone metabolism could be useful for clinical evaluation of fracture healing and early diagnosis of osteomyelitis. ( J Am Vet Med Assoc 2003;64:727–735)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the efficacy of IV administration of a product containing hyaluronan, sodium chondroitin sulfate, and N-acetyl-d-glucosamine for prevention or treatment of osteoarthritis in horses.

ANIMALS 32 healthy 2- to 5-year-old horses.

PROCEDURES The study involved 2 portions. To evaluate prophylactic efficacy of the test product, horses received 5 mL of the product (n = 8) or saline (0.9% NaCl) solution (8; placebo) IV every fifth day, starting on day 0 (when osteoarthritis was induced in the middle carpal joint of 1 forelimb) and ending on day 70. To evaluate treatment efficacy, horses received either the product or placebo (n = 8/treatment) on days 16, 23, 30, 37, and 44 after osteoarthritis induction. Clinical, diagnostic imaging, synovial fluid, gross anatomic, and histologic evaluations and other tests were performed. Results of each study portion were compared between treatment groups.

RESULTS Limb flexion and radiographic findings were significantly worse for horses that received the test product in the prophylactic efficacy portion than for placebo-treated horses or product-treated horses in the treatment efficacy portion. In the prophylactic efficacy portion, significantly less articular cartilage erosion was identified in product-treated versus placebo-treated horses. In the treatment efficacy portion, joints of product-treated horses had a greater degree of bone edema identified via MRI than did joints of placebo-treated horses but fewer microscopic articular cartilage abnormalities.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that caution should be used when administering the evaluated product IV to horses, particularly when administering it prophylactically, as it may have no benefit or may even cause harm.

Full access
in American Journal of Veterinary Research

Objective—

To determine the outcome of horses after arthroscopic removal of abaxial fracture fragments of the proximal sesamoid bone and association of fracture grade with outcome.

Design—

Retrospective study.

Animals—

47 horses.

Procedure—

Information obtained from dorsopalmar and dorsoplantar radiographic views of metacarpophalangeal and metatarsophalangeal joints was used to classify fractures as grade 1 (< 15 mm long), grade 2 (15 to 25 mm long), and grade 3 (> 25 mm long) and type 1 (abaxial) and type 2 (apical-abaxial). Outcome was determined by whether the horse returned to its intended use, raced in the same class or higher (racehorses), or performed satisfactorily (nonracehorses). Number of starts, performance index, and money earned were also used to evaluate performance of racehorses.

Results—

Follow-up information was obtained for 41 horses (35 racehorses, 6 nonracehorses). Twenty-five racehorses were able to return to racing (16 in the same class, 9 in a lower class). All 6 nonracehorses were able to return to performance at the same level. Horses with small fracture fragments or fractures involving the abaxial aspect of the proximal sesamoid bone only had a more favorable outcome, compared with horses with large or apical-abaxial fractures.

Clinical Implications—

Overall, horses with abaxial fractures of the proximal sesamoid bone have a favorable prognosis for return to racing, but only a fair prognosis for return to racing in the same class, after arthroscopic removal of fracture fragments. Successful results can be expected for nonracehorses. (J Am Vet Med Assoc 1998:213:1016-1021)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objectives

To clone equine interleukin 1α (IL-1α) and equine interleukin 1β (IL-1β) and determine their full-length cDNA sequences.

Procedure

The mRNA isolated from lipopolysaccharide-stimulated cultured equine monocytes was reverse transcribed, and a cDNA library was constructed in a λ phage. The cDNA library was screened by means of plaque hybridization with radiolabeled human IL-1α and IL-1ß cDNA probes. The cDNA nucleotide sequences for equine IL-1α and equine IL-1β were determined by use of the dideoxy chain termination technique. The cDNA sequences were analyzed, using computer software, for sequence characteristics and compared with sequences reported for other species.

Results

The cDNA for equine IL-1α was 1,728 base pairs in length with an ORF encoding a peptide of 270 amino acids with a predicted molecular mass of 30.823 kd. The cDNA for equine IL-1β was 1,473 base pairs in length with an ORF encoding a peptide of 268 amino acids with a predicted molecular mass of 30.342 kd. Similarity between amino acid sequence of equine IL- 1α and sequences for IL-1 α of other species ranged from 62.5 to 82.2%; similarity between amino acid sequence of equine IL-1ß and sequences for IL-1β of other species ranged from 62.5 to 66.4%. Similarity between amino acid sequences of equine IL-1α and equine IL-1β was 26%.

Conclusions and Clinical Relevance

Results establish a basis for studying the roles of interleukin 1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:704-711)

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To clone equine interleukin 1 receptor antagonist (IL-1 ra) and determine its full-length cDNA sequence.

Procedure

A cDNA library derived from lipopolysaccharide-stimulated equine monocytes was screened by means of plaque hybridization to radiolabeled equine IL-1ra DNA probes generated by means of the polymerase chain reaction. The cDNA nucleotide sequence for equine IL-1ra was determined by use of the dideoxy chain termination technique, analyzed by use of computer software for sequence characteristics, and compared with sequences reported for IL-1ra of other species.

Results

The cDNA for equine IL-1ra was 1,614 base pairs in length with an ORF encoding a peptide of 177 amino acids with a predicted molecular mass of 20.427 kd. Similarity between the amino acid sequence of equine IL-1ra and sequences for human, murine, rat, and lapine IL-1ra was 76%. Similarity between sequence for equine IL-1ra and sequences for equine interleukin-1α and equine interleukin-1ß were 22.6 and 24.6%, respectively.

Conclusion

Comparison of the sequence for equine IL-1ra with sequences for IL-1ra of other species indicated a high degree of conservation.

Clinical Relevance

Results establish a basis for studying the roles of interleukin-1 in healthy and diseased joints in horses. (Am J Vet Res 1998;59:712-716)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate the effects of a commercially defined, serum-free medium additive on equine articular cartilage explants, compared with effects of serum-free and serum-supplemented media.

Animals

Articular cartilage from a 3-year-old, mixed breed horse euthanatized for reasons other than musculoskeletal disease or sepsis.

Procedure

Media were changed every 48 hours, and the glycosaminoglycan (GAG) content was determined in media collected at each time point. Glycosaminoglycan synthesis by explant chondrocytes, and residual GAG content of articular cartilage (as a measure of explant GAG loss) were determined at the end of the study (day 8).

Results

Articular cartilage explants in serum-free medium and the commercial supplemented medium had significantly lower GAG synthesis and GAG content than did those incubated in serum-supplemented medium. There were no significant differences in GAG synthesis and content between serum-free and commercial supplemented medium groups. When comparing medium GAG content for all treatment groups, the GAG content in serum-free medium on day 8 was significantly greater than that in commercial supplemented medium, but significant differences were not evident in percentage of release of GAG (as an indicator of GAG degradation) among all 3 treatment groups.

Conclusions

Commercial supplemented medium had effects on articular cartilage matrix GAG loss into medium equal to those of serum-supplemented medium (eg, both lost articular cartilage explant GAG to a similar degree). However, residual articular cartilage GAG content was higher in serum-supplemented medium, as was GAG synthesis. Commercial supplemented medium appears to either lack the proper ingredients to maintain steadystate GAG synthesis, or lacks proper concentrations of these ingredients. (Am J Vet Res 1996;57:1261–1265)

Free access
in American Journal of Veterinary Research

SUMMARY

Periosteal autografts were used for repair of large osteochondral defects in 10 horses aged 2 to 3 years old. In each horse, osteochondral defects measuring 1.0 × 1.0 cm2 were induced bilaterally on the distal articular surface of each radial carpal bone. Control and experimental defects were drilled. Periosteum was harvested from the proximal portion of the tibia and was glued into the principal defects, using a fibrin adhesive. Control defects were glued, but were not grafted.

Sixteen weeks after the grafting procedure, the quality of the repair tissue of control and grafted defects was assessed biochemically. Total collagen content and the proportion of type-II collagen were determined. Galactosamine and glucosamine contents also were determined. From these measurements, contents of chondroitin and keratan sulfate and total glycosaminoglycan, and galactosamine-to-glucosamine ratio were calculated. All biochemical variables were compared with those of normal equine articular cartilage taken from the same site in another group of clinically normal horses. Total collagen content was determined on the basis of 4-hydroxyproline content, using a colorimetric method. The proportions of collagen types I and II in the repair tissue were assessed by electrophoresis of their cyanogen bromide-cleaved peptides on sodium dodecyl sulfate slab gels. Peptide ratios were computed and compared with those of standard mixtures of type-I and type-II collagens. Galactosamine and glucosamine contents were determined by use of ion chromatography.

In general, the biochemical composition of repair tissue of grafted and nongrafted defects was similar, but clearly differed from that of normal articular cartilage. Total glycosaminoglycan content, galactosamine and glucosamine contents, and galactosamine-to-glucosamine ratio of grafted and nongrafted defects were all significantly (P < 0.05) less than corresponding values in normal equine articular cartilage. By contrast, total collagen content of neocartilaginous tissues of grafted and nongrafted defects was greater than that of normal articular cartilage, although the difference was not significant. The proportion of type-I and type-II collagens in repair tissue in grafted and nongrafted defects was 70 and 30%, respectively. The fibrous nature of the repair tissue reported in a companion morphologic and histochemical study was substantiated by the biochemical results. We concluded that use of periosteal autografts did not improve the healing of osteochondral defects.

Free access
in American Journal of Veterinary Research