Intra-Articular Injection of 2 Different Dosages of Autologous and Allogeneic Bone Marrow- and Umbilical Cord-Derived Mesenchymal Stem Cells Triggers a Variable Inflammatory Response of the Fetlock Joint on 12 Sound Experimental Horses

Abstract

Osteoarthritis is a significant and costly cause of pain for both humans and horses. The horse has been identified as a suitable model for human osteoarthritis. Regenerative therapy with allogeneic mesenchymal stem cells (MSCs) is a promising treatment, but the safety of this procedure continues to be debated. The aim of this study is to evaluate the safety of intra-articular injections of allogeneic MSCs on healthy joints by comparing two different dosages and two different tissue sources, namely, bone marrow and umbilical cord blood, with a placebo treatment on the same individuals. We also assessed the influence of autologous versus allogeneic cells for bone marrow-derived MSC treatment. Twelve clinically sound horses were subjected to injections in their 4 fetlock joints. Each of the three fetlocks was administered a different MSC type, and the remaining fetlock was injected with phosphate-buffered saline as a control. Six horses received 10 million cells per joint, and the 6 other horses received 20 million cells per joint. Clinical and ultrasound monitoring revealed that allogeneic bone marrow-derived MSCs induced significantly more synovial effusion compared to umbilical cord blood-derived MSCs but no significant difference was noted within the synovial fluid parameters. The administration of 10 million cells in horses triggered significantly more inflammatory signs than the administration of 20 million cells. Mesenchymal stem cell injections induced mild to moderate local inflammatory signs compared to the placebo, with individual variability in the sensitivity to the same line of MSCs. Understanding the behavior of stem cells when injected alone is a step towards the safer use of new strategies in stem cell therapy, where the use of either MSC secretome or MSCs combined with biomaterials could enhance their viability and metabolic activity.

Safety and efficacy of a mesenchymal stem cell intramammary therapy in dairy cows with experimentally induced Staphylococcus aureus clinical mastitis

“…To our knowledge this is the first report that has evaluated the effect of the intramammary administration of MSCs for the treatment of bovine mastitis. Considering the absence of previous references and the lack of consensus on the appropriate dosage of MSCs for local therapy, the number of cells used in the present study (2,5 × 10 7 ) was established according to previous reports in other large animal models including intra-articular administration in horses 21,22 , intra-uterine inoculation in mares 23,24 and intra-myocardial injection in pigs 25 . After inoculation, MSCs exert their "homing" capacity by migrating to injured tissue, in response to chemotactic factors including stromal cell-derived factor-1 (SDF-1) and regulated on activation, normal T cell expressed and secreted (RANTES) 26 .…”

The isolation and characterisation of equine bone marrow stem cell derived extracellular vesicles – evidence of an anti-inflammatory action on chondrocytes.

“…Upon reaching approximately 80% confluence at passage 2, the cells were passaged as above before being cultured in the appropriate differentiation medium. Osteogenic Differentiation 2X10 5 MSCs were plated into a 6 well plate with standard culture media for 24 hours. The media was then removed, the cells washed once with PBS before being cultured in Osteogenic differentiation media (Culture media, 3.5mM β glycerophosphate (Sigma, UK), 10nm…”

“…Treatment of OA is challenging, with no disease modifying therapies available. The use of MSC to treat equine OA has increased in recent years and whilst intraarticular MSC are considered to be safe to administer, it is well recognised that, in the horse, these injections can cause transient inflammation and synovitis (5). Additionally there are other complications and disadvantages of using MSC including limited cell survival, immunerejection, senescence-induced genetic instability or loss of function and the theoretical risk of malignant transformation (6,7).…”

An experimentally induced osteoarthritis model in horses performed on both metacarpophalangeal and metatarsophalangeal joints: Technical, clinical, imaging, biochemical, macroscopic and microscopic characterization

“…Clinical evaluations were composed of the measurement of fetlock joint circumference and the evaluation of sensitivity to static digital flexion tests and joint effusion using a five-point scale ranging from normal to severe (0-normal, 1-mild, 2-moderate, 3-substantial, 4-severe), as previously described [19] (Table 1). As the study design did not permit the evaluation of bilateral lameness, follow-up lameness evaluations were only performed one day, three days and seven days after the injection of the stem cells (W3) to rule out the presence of an adverse event (i.e.…”

“…The third main limitation of this study design is that all horses received intra-articular injections of stem cells on W3. The stem cells injected were from the same cell lines as those previously used in a safety study [19] and were not considered to have any relevant systemic effects in the analysis. The immunomodulatory properties of stem cells have been widely reported but their mechanisms of action have not been described in detail, research published to date has only focused on the general administration of stem cells.…”