Mechanism of Action
The mechanism of action of AUGMENT® Bone Graft is dependent on the role of both the matrix and the biologic components.
The matrix component (β-TCP) supplies the primary mode of action, providing an osteoconductive scaffold on which new cells can migrate and attach. It also serves to retain and deliver the rhPDGF-BB solution at the surgical site.
The biologic component (rhPDGF-BB) serves to provide an active stimulus for healing through three significant modes of action:
The first step in the repair of damaged tissue is the migration of reparative cells to the site of injury. The process of cell attraction and migration is known as chemotaxis.
As shown by 1Fiedler (2002), PDGF has a superior ability to recruit mesenchymal cells (cells that are precursors to bone, tendon, ligament and cartilage) relative to other common bone proteins. Values are in units of chemotactic index (CI).
1Fielder (2002) Journal of Cellular Biochemistry
Mitogenesis, also known as proliferation, refers to the process of stimulating cells to divide. Cell division increases the total number of cells and ensures sufficient numbers to provide an adequate healing response. PDGF is a potent mitogen of cells of mesenchymal (musculoskeletal) origin.
In this study from 2Ozaki (2007) mesenchymal stem cells were separately exposed to multiple growth factors in a study used to assess cell proliferation. The values reported are proportional to the level of cell proliferation. PDGF-BB was the most potent growth factor tested.
2Ozaki (2007) Steam Cells and Development
Regeneration of any tissue is dependent upon the availability of an adequate blood supply. PDGF is directly involved in the regulation of vascular endothelial growth factor (VEGF), a molecule which is critical for stimulating production of new blood vessels (angiogenesis).
As shown by 3Bouletreau (2002), PDGF directly influences the expression of VEGF (vascular endothelial growth factor) in a dose-dependent manner.
3Bouletreau (2002) Plastic and Reconstructive Surgery