Single and repeated intra‐articular injections in the tarsocrural joint with allogeneic and autologous equine bone marrow‐derived mesenchymal stem cells are safe, but did not reduce acute inflammation in an experimental interleukin‐1β model of synovitis

Abstract

Background Allogeneic and autologous bone marrow‐derived mesenchymal stem cells (BMDMSCs) have been administered in equine joints for their anti‐inflammatory effects. However, allogeneic BMDMSC offer multiple clinical and practical advantages. Therefore, it is important to determine the relative effectiveness of allogeneic vs autologous BMDMSCs. Objectives The objective of the study was to compare the inflamed joint response to autologous vs allogeneic BMDMSCs injections, and to determine if either treatment generated an anti‐inflammatory effect. Study design Randomised controlled study. Method Bone marrow was harvested from eight horses. Autologous BMDMSCs and pooled allogeneic BMDMSCs were culture expanded, cryopreserved and thawed immediately prior to administration. Ten million autologous BMDMSCs were administered with 75 ng rIL‐1β into one tarsocrural joint and the contralateral tarsocrural joint received allogeneic BMDMSC plus 75 ng rIL‐1β. Repeat injections were performed with the same treatment administered into the same joint. Four additional horses received 75 ng rIL‐1β alone in a single tarsocrural joint. Clinical parameters (lameness, joint circumference and joint effusion) and synovial fluid parameters, including nucleated cell count (NCC), differential cell count, total protein (TP), prostaglandin E2 (PGE2) and C‐reactive protein (CRP), were measured at baseline, 6, 12, 24, 72, 168 and 336 hours post‐injection. Results No difference was detected between autologous and allogeneic treatment groups with respect to subjective lameness, joint effusion, joint circumference, NCC, TP, differential cell count, CRP or PGE2. Neither autologous nor allogeneic treatments resulted in an improvement in clinical or cytological parameters over that elicited by rIL‐1β alone. Main limitations A single dose of rIL‐1β was evaluated and resulted in a severe synovitis which may have been too severe to observe a BMDMSC‐mediated effect. Conclusions This study revealed that allogeneic and autologous BMDMSCs resulted in an equivalent clinical and cytological response. Allogeneic and autologous BMDMSCs were equally ineffective in reducing the inflammatory response from acute rIL‐1β‐induced joint inflammation in horses.

Interactions Between Allogeneic Mesenchymal Stromal Cells and the Recipient Immune System: A Comparative Review With Relevance to Equine Outcomes

“…A study using a chemically induced-model of arthritis in the horse showed significant upregulation of type 2 collagen and significantly decreased expression of inflammatory mediators in cartilage at 6 months post-treatment when allogeneic MSC-treated joints were compared to untreated joints, though no significant gross nor histologic improvement was seen (Table 2) (33). In a similar study, allogeneic MSCs did not cause significant clinical improvement in IL-1beta-induced arthritis, however, this was a very acute and severe inflammatory model (Table 2) (97). Additional allogeneic MSC studies focusing on joint disease in the horse have shown beneficial clinical and histologic results using blood-derived (81), neonatal-derived (82), or adiposederived MSCs (Table 2) (83).…”

Preparation Technique Affects Recipient Immune Targeting of Autologous Mesenchymal Stem Cells

“…We show that recipient anti-bovine titers cause antibody mediated death of MSCs that have been prepared with FBS, with resultant local inflammation and reduced synovial MSCs after intra-articular administration. The historic and current use of FBS for MSC preparation is likely to misrepresent MSC effect because of cytotoxicity and adverse responses to MSCs with FBS contamination ( 10 , 42 , 49 ). When evaluating reported pre-clinical, veterinary, and human clinical trials, the use of FBS should be considered when interpreting results ( 4 , 9 , 40 , 41 ).…”

“…However, the use of FBS is decreasing because of ethical concerns, availability, and the risk of disease transmission from bovine products (7). Despite this shift in FBS acceptance, FBS supplemented MSCs have market approval for use in humans in Canada and New Zealand, and FBS supplementation remains the industry standard in pre-clinical and veterinary MSC use (4,5,(8)(9)(10)(11).…”

Regenerative Medicine for Equine Musculoskeletal Diseases

“…Adult articular cartilage has very limited ability for self-repair and current treatment strategies, such as NSAIDs and intra-articular injections with corticosteroids, are only palliative in nature and have little impact on the progressive degeneration of articular cartilage [ 152 , 153 , 154 , 155 , 156 ]. Consequently, there is a large unmet need for efficacious disease-modifying therapies, and thus a growing interest in regenerative medicine approaches.…”

“…To further improve the effect of MSC therapies proinflammatory or chondrogenic priming strategies for MSC prior to injection were tested, the latter of which was proven to be safe although differentiation of equine bmMSCs may increase the expression of immunogenic proteins [ 31 , 168 , 169 ]. Additionally, the intra-articular administration of allogeneic and even xenogeneic MSCS for the treatment of OA has been tested in multiple clinical studies in horses with equivocal results [ 156 , 170 , 171 ]. Although some studies show an immune reaction to allogeneic and xenogeneic stem cells [ 172 ], the immune response in vivo seems to be mild, and allogeneic MSCs application has been reported to be safe for intra-articular use in equine patients [ 173 , 174 , 175 , 176 ].…”