Insights into mesenchymal stem cell aging: involvement of antioxidant defense and actin cytoskeleton.

Progenitor cells such as mesenchymal stem cells (MSCs) have elicited great hopes for therapeutic augmentation of physiological regeneration processes, e.g., for bone fracture healing.

Locally applied osteogenic predifferentiated progenitor cells are more effective than undifferentiated mesenchymal stem cells in the treatment of delayed bone healing.

Mesenchymal stem cells (MSCs) and osteogenic predifferentiated cells (OPCs) have been shown to promote healing of critical-sized bone defects. This study investigated the regenerative capacity of autologous MSCs versus OPCs after local injection into a compromised bone healing situation. We hypothesized that treatment with MSCs and OPCs would enhance the healing and that the MSCs would be more effective due to their lower differentiation and higher proliferative competence.

A new animal model for bone atrophic nonunion: fixation by external fixator.

A new small animal model of bone atrophic nonunion was established for investigating the process of bone regeneration by performing cauterization of the periosteum, removal of the local bone marrow, and stabilization with external fixation. The model allows the creation of an atrophic nonunion without the need for a critical size defect. Furthermore, it provides reproducible, well-defined mechanical conditions and minimized physical interference of the implant with the biological processes in the healing zone.

Influence of age and mechanical stability on bone defect healing: age reverses mechanical effects.

Non-unions and delayed healing are still prevalent complications in fracture and bone defect healing. Both mechanical stability and age are known to influence this process. However, it remains unclear which factor dominates and how they interact.

An easily reproducible and biomechanically standardized model to investigate bone healing in rats, using external fixation.

Abstract We have established a new small animal model to investigate the process of bone regeneration. A total of 42 male Sprague-Dawley rats received an osteotomy of the left femur, stabilized with a custom-made external fixator. The fixation method was chosen to create an easily reproducible, biomechanically well-defined model with minimized interference of the implant with the healing zone.