Methods: Fractionated commercial Emdogain® (EMD) was obtained from Straumann International. 60 CDI 7 day old outbred mice were injected using 50 μl aliquots of 10 µg EMD, 10 µg Pool 7 EMD, 2 µg TGF-β (positive control) or phosphate buffered saline (PBS, negative control) delivered in a calvarial injection model. Injections were done for 5 consecutive days. The animals were sacrificed on days 6, 8, 12, 16 and 21 with 6 animals per factor for each time point and were prepared for histological evaluation. Nikon NIS Elements software was used to analyze vascular growth and new bone formation over the five time intervals at 20x magnification. Immunocytochemistry (IHC) was used to identify the kinetics of osteogenesis by evaluating the osteoblast transcription factor Osterix, and the angiogenic signaling molecule, Vascular Endothelial Growth Factor (VEGF) native to pool 7.
Results: EMD Pool 7 showed an enhanced capacity for promoting osteogenesis and angiogenesis vs. EMD. In general terms, EMD Pool 7 elicits early bone marrow formation coupled with a relative spike in osterix expression, indicative of highly active osteoblastogenesis, followed by biphasic increased of bone formation at days 12 and 21. At day 21, large spikes in osterix and VEGF expression are observed with an exponential increase in bone marrow growth demonstrating powerful osteogenic angiogenic properties of EMD Pool 7.
Conclusions: EMD POOL 7 showed promise in activating enhanced angiogenesis and osteogenesis. Understanding the underlying mechanisms and kinetics orchestrated by Emdogain® will add much needed information regarding the activation of regenerative properties and lead to increased efficacy in future clinical products.