title: MRI-Based Assessment of Intralesional Delivery of Bone Marrow-Derived Mesenchymal Stem Cells in a Model of Equine Tendonitis.
abstract: Ultrasound-guided intralesional injection of mesenchymal stem cells (MSCs) is held as the benchmark for cell delivery in tendonitis. The primary objective of this study was to investigate the immediate cell distribution following intralesional injection of MSCs. Unilateral superficial digital flexor tendon (SDFT) lesions were created in the forelimb of six horses and injected with 10 × 106MSCs labeled with superparamagnetic iron oxide nanoparticles (SPIOs) under ultrasound guidance. Assays were performed to confirm that there were no significant changes in cell viability, proliferation, migration, or trilineage differentiation due to the presence of SPIOs. Limbs were imaged on a 1.5-tesla clinical MRI scanner postmortem before and after injection to determine the extent of tendonitis and detect SPIO MSCs. Clusters of labeled cells were visible as signal voids in 6/6 subjects. Coalescing regions of signal void were diffusely present in the peritendinous tissues. Although previous reports have determined that local injury retains cells within a small radius of the site of injection, our study shows greater than expected delocalization and relatively few cells retained within collagenous tendon compared to surrounding fascia. Further work is needed if this is a realityin vivoand to determine if directed intralesional delivery of MSCs is as critical as presently thought.
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; Department of Biological and Agricultural Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Scharf
authors.affiliation: Veterinary Biosciences and Diagnostic Imaging, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: Shannon P
authors.initials: SP
authors.lastname: Holmes
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: Merrilee
authors.initials: M
authors.lastname: Thoresen
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Mumaw
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: Alaina
authors.initials: A
authors.lastname: Stumpf
authors.affiliation: Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: John
authors.identifier: 0000-0002-5031-8848
authors.initials: J
authors.lastname: Peroni