Peptide Coated Titanium Rods Show Increased Bone Formation in a Rat Femur Model

Abstract

In vitro, groups have demonstrated that peptide modified surfaces influence short and long term cell responses like attachment, shape and function via cell receptors known as integrins. These receptors translate information to the nucleus via sets of complex signaling pathways. Little is known about the ability of these surfaces to influence the inherently complex in vivo environment, however. The present study was designed to evaluate the quality and quantity of new bone formed in response to gold coated titanium rods modified with the peptide sequence Arg-Gly-Asp-Cys (RGDC). Quantitative histomorphometric analysis of histologic sections perpendicular to the implant long axis showed a thicker (P < 0.01) shell of new bone formed in response to peptide modified implants (26.2 microns ± 1.9 vs. 20.5 microns ± 2.9) as early as 2 weeks. Mechanical pull-out testing conducted at 4 weeks revealed the average pull-out force of peptide modified rods was 38% greater than gold control rods. The significant difference in the thickness of new bone formed around the implant was maintained at 4 weeks (32.7 microns ± 4.6 vs. 22.6 microns ± 4.0). These results demonstrate the feasibility of developing peptide coated biomaterials designed to elicit a host response at the cell receptor level.