Scintigraphic Tracking of Allogeneic Mesenchymal Stem Cells in the Distal Limb After Intra-Arterial Injection in Standing Horses.
Authors: Espinosa Pablo, Spriet Mathieu, Sole Albert, Walker Naomi J, Vaughan Betsy, Galuppo Larry D
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Intra-arterial Mesenchymal Stem Cell Administration in Standing Horses Researchers investigated whether allogeneic mesenchymal stem cells could be safely injected directly into the median artery of the distal limb in standing, sedated horses, and tracked their distribution using radiolabelled cells and scintigraphic imaging. Using technetium-99m labelling in six horses (12 limbs total), the team performed ultrasound-guided injections and captured images immediately post-injection and at 1, 6, and 24 hours, whilst an additional six unlabelled limbs served as controls for vascular assessment. Successful arterial placement was achieved in 11 of 12 limbs, with radiolabelled cells distributing homogeneously throughout the distal limb including the hoof tissue; partial venous thrombosis occurred in both groups but appeared less severe in unlabelled controls, whilst clinical lameness was absent and transient swelling minimal. The intra-arterial route represents a viable method for delivering stem cells to distal limb tissues in conscious horses with manageable complication rates, though practitioners should anticipate partial thrombosis as a likely sequela and recognise that technical precision—supported by adequate sedation and analgesia—directly influences safety outcomes. For those considering MSC therapy for conditions affecting the distal limb, this work demonstrates feasibility in standing patients but highlights the importance of operator experience and careful technique to minimise the risk of periarterial injection.
Read the full abstract on PubMed
Practical Takeaways
- •Intra-arterial MSC delivery to the distal limb is technically feasible in standing horses under sedation with proper ultrasound guidance, offering potential for targeted treatment of distal limb conditions
- •Practitioners should be aware that periarterial injection is a procedural risk (8% in this study) that can be minimized through adequate sedation, local anesthesia, and operator experience
- •Minor venous thrombosis is an expected consequence of the procedure that typically resolves without clinical consequence, though continued monitoring for lameness is warranted post-treatment
Key Findings
- •Intra-arterial MSC injection was successfully performed in 11 of 12 limbs (91.7% success rate) in standing sedated horses
- •Radiolabeled MSCs distributed homogeneously throughout the distal limb including the hoof within 1-24 hours post-injection
- •Partial venous thrombosis occurred in both labeled and unlabeled MSC groups but caused no clinically significant lameness or complications except one case of transient swelling