Graduate Student Louisiana State University Baton Rouge, Louisiana
De Novo Tendon Neotissue from Equine Adult Stem Cells. Taguchi T, Lopez M. Louisiana State University, School of Veterinary Medicine, Laboratory for Equine and Comparative Orthopedic Research, Baton Rouge, LA.
Tendon injuries account for many equine musculoskeletal disorders; healing is limited, and scarring is common. Implantation of neotissue may improve tendon healing since tenoblasts migrate to and replace scar tissue in neonates. The two-part hypothesis of this study was that equine adipose-derived multipotent stromal cells (ASCs) cultured on collagen I templates assume a tenoblast-like morphology, express tendon-specific genes, and produce organized extracellular matrix (ECM) in tenogenic versus stromal medium with static strain; dynamic strain increases gene expression and ECM deposition in tenogenic medium. Cell-collagen constructs cultured in stromal or tenogenic medium with static or dynamic strain were assessed for cell growth kinetics, gene expression, and micro- and ultra-structure with viability stain and resazurin reduction, RT-PCR, and light and electron microscopy, respectively. With static strain, cells remained spherical in stromal medium, and assumed a spindle shape in tenogenic medium after 14 days. Expression of early growth response 1 and connective tissue growth factor at day 7 and Col1a1 at day 14 increased, while mohawk decreased at day 14 in tenogenic versus stromal medium. After 21 days of culture with static strain, parallel, spindle-shaped cells were embedded in fibrous ECM in tenogenic medium; with dynamic strain, spherical cells were surrounded by granulofilamentous ECM characteristic of high elastin. Tendon neotissue formed by equine ASCs on collagen I in tenogenic medium with static strain resembles the proliferation phase of tendon healing; dynamic strain appears to accelerate maturation. De novo neotendon generation may provide a mechanism for study and treatment of equine tendinopathy.