abs: Lymphocyte populations CD4+ and CD8+ response to repeated intralesional injection of superficial digital flexor tendon core lesions with Allogeneic Equine Cord Blood-Derived Mesenchymal Stromal Cells Large Animal Residents' Forum
DVSc, LA Surgery Resident Ontario Veterinary College, University of Guelph Guelph, Ontario, Canada
Lymphocyte Populations CD4+ and CD8+ Response to Repeated Intralesional Injection of Superficial Digital Flexor Tendon Core Lesions with Allogeneic Equine Cord Blood-Derived Mesenchymal Stromal Cells. Merchan Munoz A, Koenig J, Mehrpouyan S, Haji Alizadeh A, Monteith G, Cote N, Koch T. University of Guelph, Ontario Veterinary College, Guelph, ON, Canada.
The immune response caused by repeated injection of allogeneic umbilical cord blood mesenchymal stem cells (CB-MSC) into equine tendons has not been assessed. We compared the repeated intralesional injection of allogeneic CB-MSC for treatment of superficial digital flexor tendonitis with repeated platelet rich plasma (PRP) injections. We hypothesized that the repeated intralesional use of allogeneic CB-MSC for treatment of naturally occurring superficial digital flexor tendinitis in horses is safe. Seven Thoroughbred racehorses, in speed training and racing, with a superficial digital flexor tendon lesion were randomly assigned to one of two groups, CB-MSC or PRP. Ultrasound-guided intralesional injections were performed at zero and four weeks, and horses were hospitalized for three days. CD4+ and CD8+ lymphocyte populations were analyzed by flow cytometry at 0, 24, 72, and 168 hours. Physical exam parameters remained within normal limits in both groups throughout hospitalization. Horses receiving CB-MSC exhibited an increased temperature at the injection site for the following 24 to 48 hours. One horse in the CB-MSC group developed a moderate lameness which resolved after 48 hours with anti-inflammatory treatment. Lymphocyte CD4+expression was significantly lower after the second treatment with CB-MSC than after the first treatment. Both CD4+ and CD8+ lymphocyte expression decreased after injection from 24 hours to 72 hours posttreatment.