Effects of anorganic bone mineral coated with various cell adhesion peptides on osteoblast response and bone formation

Bone formation is related to the adherence of osteoblasts to the graft material. The adherence of osteoblastic cells can be enhanced by coating the graft materials with specific cell binding peptides of the extracellular matrix(ECM) proteins. These interactions of osteoblasts with the ECM proteins represent essential environmental signals necessary for regulating proliferation and differentiation of osteoblast. Osteoblasts particularly interact with the ECM proteins of bone. RGD and PHSRN motifs from FN, EPDIM and YH motifs from βig-h3 and T-CAM were well known for cell adhesion peptides. This study investigated the osteoactivities of ABM/T-CAM compared to those of ABM/βig-h3 and ABM/FN by evaluating osteosblastic cell activity and new bone formation in experimentally created osseous defects respectively. The results of in vitro study demonstrated improved cell viability on ABM/βig-h3, ABM/FN and ABM/T-CAM groups compared to that on uncoated ABM group at 1, 4 and 7 days of culture. There was especially significant improvement of cell viability on ABM/T-CAM compared with that on the others groups at 1, 4 and 7 days(p<0.05). There were no significant differences in ALP activity among groups at 5 and 10 days of culture(p>0.05). ALP activity showed a increased tendency in ABM/T-CAM group compared to that of ABM and ABM/βig-h3 groups. In vivo study, at 4 weeks of healing in rabbit calvarial defects, these cell adhesion peptides-coated ABM groups exhibited osteoconductive properties. There were more new bone formations in the ABM/βig-h3, ABM/FN and ABM/T-CAM groups when compared with those in ABM only group, however there was not a prominence enough to be significant statistically(p>0.05). In conclusion, this study indicates that the cell adhesion peptides(T-CAM, RGD and PHSRN motifs from FN, EPDIM and YH motifs from βig-h3) coated bone substitutes may be biocompatible and have the potential efficacy in treating osseous defects.