Implantation of bone marrow‐derived mesenchymal stem cells demonstrates improved outcome in horses with overstrain injury of the superficial digital flexor tendon

Abstract

SummaryReasons for performing study: Mesenchymal stem (progenitor; stromal) cell (MSC) therapy has gained popularity for the treatment of equine tendon injuries but without reports of long-term follow-up. Objectives: To evaluate the safety and reinjury rate of racehorses after intralesional MSC injection in a large study of naturally occurring superficial digital flexor tendinopathy and to compare these data with those published for other treatments. Methods: Safety was assessed clinically, ultrasonographically, scintigraphically and histologically in a cohort of treated cases: 141 client-owned treated racehorses followed-up for a minimum of 2 years after return to full work. Reinjury percentages were compared to 2 published studies of other treatments with similar selection criteria and follow-up. The number of race starts, discipline, age, number of MSCs injected and interval between injury and treatment were analysed. Results: There were no adverse effects of the treatment with no aberrant tissue on histological examination. The reinjury percentage of all racehorses with follow-up (n = 113) undergoing MSC treatment was 27.4%, with the rate for flat (n = 8) and National Hunt (n = 105) racehorses being 50 and 25.7%, respectively. This was significantly less than published for National Hunt racehorses treated in other ways. No relationship between outcome and age, discipline, number of MSCs injected or injury to implantation interval was found. Conclusions: Whilst recognising the limitations of historical controls, this study has shown that MPC implantation is safe and appears to reduce the reinjury rate after superficial digital flexor tendinopathy, especially in National Hunt racehorses. Potential relevance: This study has provided evidence for the long-term efficacy of MSC treatment for tendinopathy in racehorses and provides support for translation to human tendon injuries.

CORR® ORS Richard A. Brand Award for Outstanding Orthopaedic Research: Engineering Flexor Tendon Repair With Lubricant, Cells, and Cytokines in a Canine Model

“…Adult mesenchymal stem cells most commonly are used clinically and experimentally. Although the adult mesenchymal stem cells can be derived from bone marrow, adipose, muscle, and other tissue, the most common use in tendon healing to date is the use of bone marrow stromal cells to treat equine flexor tendon injures [3,5,19,22,23].…”

The past, present and future in scaffold-based tendon treatments

“…Thus, delivery of cells is clearly more beneficial than any single or even dual biological molecule delivery strategy, which has little chance of commercialisation, given the complexity of the system. To this end, direct cell injections were pioneered, with positive results in equine patients [44,214], even with low number of cells [215][216][217]. However, direct cell injections have failed to deliver in a consistent manner in humans due to poor cell localisation [218][219][220][221], triggering an extensive investigation into the optimal cell carrier for tendon repair [1].…”

Adipose tissue as mesenchymal stem cells source in equine tendinitis treatment

“…There are promising studies about the use of cellular therapy to treat equine tendinitis. Clinical study results, for instance, have shown significant reduction in tendinitis relapse rates after at least two-year follow up applied to animals treated with cellular therapy in comparison to those treated with conventional therapies; their relapse rate was 27% and 56%, respectively (GODWIN et al, 2012).…”

“…The conventional treatment options for tendinitis are basically clinical and surgical; however, the animals hardly present healing quality good enough to allow their return to competitions with the same performance they had before the injury (MARFE et al, 2012). It is common belief that the tendon is prone to inefficient healing due to the tendinous structure, which is little vascularized, relatively acellular and has limited regeneration potential (YOUNG, 2012). It is also worth highlighting the importance of type I collagen, which is the most abundant one in the healthy tendon (approximately 95% of the total collagen) and responsible for strength and elasticity.…”