The Baht Lab uses mouse models to investigate the process of bone repair and cellular differentiation. The capacity for tissues to repair and regenerate diminishes with age. Bone fracture repair in the elderly occurs at a slower rate and results in decreased bone and cartilage deposition, increased fibrosis, and prolonged inflammation at the site of injury. Likewise in vitro differentiation of bone marrow stromal cells to osteoblasts is less efficient in aged cultures than in young cultures. These findings are recapitulated in mouse models.
We have used parabiosis (anastomosis of two mice) and bone marrow transplantation to better understand aged bone fracture repair. Aged mice anastomosed to young mice or engrafted with young bone marrow are rejuvenated with respect to tibial fracture healing and bone marrow stromal cell differentiation. Furthermore, in a tissue culture system, osteogenic media conditioned by young macrophages is able to rejuvenate osteoblastic differentiation.
Current work in the Baht Lab is focused on understanding the molecular, cellular, and metabolic pathways which are involved in the observed rejuvenation of aged fracture repair and cellular differentiation.