Optimization of an ex vivo gene transfer to the hamstrings tendons muscle remnants: potential for genetic enhancement of bone healing

Human muscle tissue samples obtained from 31 patients was used in this in vitro analytical and experimental study. To optimize transduction protocol, samples from 28 patients were transduced with the adenoviral vector carrying firefly luciferase cDNA (Ad.luc) using different doses, times of transduction and addition of positive ions for transduction enhancement. The optimized protocol was further tested on muscle samples from 3 new patients, which were transduced with Ad.BMP-2. Released bone morphogenetic protein 2 (BMP-2) levels in osteogenic medium were measured every 3 days during the period of 21 days. Expression of osteogenic markers was at day 14 and 21.  After 21 days of cultivation, muscle tissue was prepared for immunohistochemical staining for collagen type I (COL-I).