title: Scintigraphic comparison of intra-arterial injection and distal intravenous regional limb perfusion for administration of mesenchymal stem cells to the equine foot.
abstract: BACKGROUND
  Intra-arterial (i.a.) and intravenous (i.v.) regional limb perfusions (RLP) through the median artery and cephalic vein, respectively, have been previously investigated for administration of mesenchymal stem cells (MSCs) to the equine distal limb. Limitations due to thrombosis of the arteries after i.a. RLP and poor distribution of MSCs to the foot with i.v. RLP were observed. These techniques need to be modified for clinical use.
  
  
  OBJECTIVE
  Evaluate the distribution, uptake and persistence of radiolabelled MSCs after i.a. injection through the median artery without a tourniquet and after i.v. RLP through the lateral palmar digital vein.
  
  
  METHODS
  In vivo experimental study.
  
  
  METHODS
  (99m) Tc-HMPAO-labelled MSCs were injected through the median artery of one limb and the lateral palmar digital vein of the other limb of 6 horses under general anaesthesia. No tourniquet was used for the i.a. injection. A pneumatic tourniquet was placed on the metacarpus for i.v. injection. Scintigraphic images were obtained up to 24 h after injection.
  
  
  RESULTS
  Intra-arterial injection resulted in MSCs retention within the limb despite the absence of a tourniquet and no thrombosis was observed. Both i.a. injection and i.v. RLP led to distribution of MSCs to the foot. The i.a. injection resulted in a more homogeneous distribution. The MSC uptake was higher with i.v. RLP at the initial timepoints, but no significant difference was present at 24 h.
  
  
  CONCLUSIONS
  Both i.a. injection through the median artery without a tourniquet and i.v. RLP performed through the lateral palmar digital vein under general anaesthesia are safe and reliable methods for administration of MSCs to the equine foot. The i.a. technique is preferred owing to the better distribution, but is technically more challenging. The feasibility of performing these techniques on standing horses remains to be investigated.
authors.affiliation: Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Trela
authors.forename: M
authors.initials: M
authors.lastname: Spriet
authors.forename: K A
authors.initials: KA
authors.lastname: Padgett
authors.forename: L D
authors.initials: LD
authors.lastname: Galuppo
authors.forename: B
authors.initials: B
authors.lastname: Vaughan
authors.forename: M A
authors.initials: MA
authors.lastname: Vidal
mesh_terms: D000818:Animals; D005528:Foot / Q000098:blood supply*; D006736:Horses; D007261:Infusions, Intra-Arterial / Q000379:methods / Q000662:veterinary*; D007262:Infusions, Intravenous / Q000379:methods / Q000662:veterinary*; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods / Q000662:veterinary*; D011877:Radionuclide Imaging / Q000662:veterinary*; D019275:Radiopharmaceuticals / Q000494:pharmacology; D019690:Technetium Tc 99m Exametazime / Q000494:pharmacology
chemical_list: D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime
keywords: HMPAO; hexamethylpropyleneamine oxime; horse; mesenchymal stem cells; regional limb perfusion; scintigraphy; technetium