Background: Bone morphogenetic proteins (BMPs) are actively involved in ossification, and BMP-2 participates throughout the entire process. Gene therapy for bone regeneration using adenovirus-expressing BMPs has been successful in small mammals, but it has not been satisfactory in large mammals.
Methods: We generated a 3-component implant (3C graft) comprising autologous mesenchymal stem cells (MSCs), ex vivo transduced with an adenovirus vector–expressing BMP-2 and embedded in a demineralized human bone matrix (DBM).
Results: In vitro studies demonstrated vector-induced osteogenesis; osteoblast population and mineralization of the extracellular matrix were greater in the vector-transduced cultures than in the controls (nontransduced MSCs stimulated with osteogenic media were used as positive controls, and nontransduced MSCs served as a negative control). The 3-component grafts were used to fill osteotomies created by bone distraction surgery in mongrel dogs. Control groups comprised dogs with bone distraction alone and dogs with nontransduced MSC grafts. The radiography follow-up, performed 10 weeks after distraction, demonstrated a remarkable reduction in the consolidation period compared with controls. Postmortem mandibles submitted for anatomic and histologic analyses showed improved remodeling and bone maturation in the 3C-grafted dogs. Inflammatory infiltrates were not observed in any of the treated areas, and no liver toxicity was detected.
Conclusions: We demonstrated acceleration of osteogenesis in a dog model for bone distraction by using an implant of BMP-2 modified MSCs. These results are helpful for future clinical trials of mandible bone distraction.
From the *Service of Plastic and Reconstructive Surgery, †Department of Biochemistry and Molecular Medicine, ‡Center for Research and Development in Health Sciences UANL (CIDCS-UANL), §Department of Morphology, ∥Service of Orthopedics and Human Bone and Tissue Biorepository, and ¶Department of Physiology. School of Medicine and University Hospital of the Universidad Autónoma de Nuevo León, Monterrey, Mexico.
Received February 21, 2011.
Accepted for publication June 29, 2011.
Address correspondence and reprint requests to Augusto Rojas-Martínez, MD, DSc, CIDCS, Universidad Autónoma de Nuevo León, Calle Carlos Canseco S. N. Colonia Mitras Centro, Monterrey, N. L., México CP 64464; E-mail: firstname.lastname@example.org
Drs Castro-Govea and Cervantes-Kardasch contributed equally to this work.
This work was supported by the Mexican Council for Science and Technology (CONACYT) SALUD grant 2008-C01-87362 and the PAICYT-UANL grant SA684-02.
The authors report no conflict of interest.