Osteoarthritis in horses and in humans is

Histological measurements of the thickness of non-calcified and calcified cartilage, as well as the subchondral bone plate in five locations on the femoral trochlea and medial femoral condyles of species were used in preclinical studies of articular cartilage and compared to those of the human knee. Cadaver specimens were obtained of six human knees, as well as six equine, six goat, six dog, six sheep and six rabbit stifle joints (the animal equivalent of the human knee). Specimens were taken from the lateral trochlear ridge, medial trochlear ridge and medial femoral condyle. After histopathological processing, the thickness of non-calcified and calcified cartilage layers, as well as the subchondral bone plate, was measured. Average articular cartilage thickness over five locations were 2.2-2.5 mm for human, 0.3 mm for rabbit, 0.4-0.5 mm for sheep, 0.6-1.3 mm for dog, 0.7-1.5 mm for goat and 1.5-2 mm for horse. The horse provides the closest approximation to humans in terms of articular cartilage thickness, and this approximation is considered relevant in pre-clinical studies of cartilage healing.

No negative effects of the microfracture technique were observed and some of the beneficial effects are the basis for recommending its use in patients cases with exposed subchondral bone.

Six synovial fluid and serum biomarkers were useful in separating early experimental OA from exercise alone but synovial fluid CTX1 and serum Col CEQ and CTX1 were not.

Results of this controlled study indicated that there was significant clinical and histologic improvement in osteoarthritis-affected joints of horses following treatment with ACS, compared with placebo treatment. On the basis of these findings, further controlled clinical trials to assess this treatment are warranted, and investigation of the mechanisms of action of ACS should be pursued concurrently.

Osteoarthritis (OA) is an important cause of pain, disability and economic loss in humans, and is similarly important in the horse. Recent knowledge on post-traumatic OA has suggested opportunities for early intervention, but it is difficult to identify the appropriate time of these interventions. The horse provides two useful mechanisms to answer these questions: 1) extensive experience with clinical OA in horses; and 2) use of a consistently predictable model of OA that can help study early pathobiological events, define targets for therapeutic intervention and then test these putative therapies. This paper summarises the syndromes of clinical OA in horses including pathogenesis, diagnosis and treatment, and details controlled studies of various treatment options using an equine model of clinical OA.

The purpose of this study was the assessment of clinical, biochemical, and histologic effects of intraarticular administered adipose-derived stromal vascular fraction or bone marrow-derived mesenchymal stem cells for treatment of osteoarthritis. Osteoarthritis was induced arthroscopically in the middle carpal joint of all horses, the contralateral joint being sham-operated. All horses received treatment on Day 14. Eight horses received placebo treatment and eight horses received adipose-derived stromal vascular fraction in their osteoarthritis-affected joint. The final eight horses were treated the in osteoarthritis-affected joint with bone marrow-derived mesenchymal stem cells. Evaluations included clinical, radiographic, synovial fluid analysis, gross, histologic, histochemical, and biochemical evaluations. No adverse treatment-related events were observed. The model induced a significant change in all but two parameters, no significant treatment effects were demonstrated, with the exception of improvement in synovial fluid effusion PGE2 levels with bone marrow-derived mesenchymal stem cells when compared to placebo. A greater improvement was seen with bone marrow-derived mesenchymal stem cells when compared to adipose-derived stromal vascular fraction and placebo treatment. Overall, the findings of this study were not significant enough to recommend the use of stem cells for the treatment of osteoarthritis represented in this model.

The proposed system for assessment of equine articular tissues provides a useful method to quantify OA change. It is believed that addition of quantitative tracing onto plastic and macroscopic measurement as recently described would be an improvement for overall assessment of articular cartilage change.