Porcine fetal enamel matrix derivative enhances bone formation induced by demineralized freeze dried bone allograft in vivo.
BACKGROUND
Embryonic enamel matrix proteins are involved in the formation of acellular cementum during development of the periodontal attachment apparatus, suggesting that these proteins might be used clinically to promote periodontal regeneration. At present, it is unknown if these proteins are osteoinductive, osteoconductive, or osteopromotive. To address this question, we examined the ability of a commercially prepared embryonic porcine enamel matrix derivative to induce new bone formation in nude mouse calf muscle, or to enhance the bone induction ability of a demineralized freeze-dried bone allograft (DFDBA).


METHODS
Porcine fetal enamel matrix derivative (EMD) was implanted bilaterally in the calf muscle of 4 male Nu/Nu mice per treatment group (N = 8 implants): 2 mg EMD alone; 4 mg EMD alone; inactive human DFDBA alone; inactive DFDBA + 2 mg EMD; inactive DFDBA + 4 mg EMD; active DFDBA alone; active DFDBA + 2 mg EMD; and active DFDBA + 4 mg EMD. Implants were harvested after 56 days and examined histologically for bone induction using a semi-quantitative score and histomorphometrically for area of new bone, cortical bone, bone marrow, and residual DFDBA.


RESULTS
Implants containing inactive DFDBA, 2 mg EMD, 4 mg EMD, and inactive DFDBA + 2 or 4 mg EMD did not induce new bone. Active DFDBA and active DFDBA + 2 mg EMD induced new bone to a similar extent. In contrast, active DFDBA + 4 mg EMD resulted in enhanced bone induction, area of new bone, and cortical bone. Residual DFDBA was also increased in this group.


CONCLUSIONS
EMD is not osteoinductive. However, it is osteopromotive, due in part to its osteoconductive properties, but a threshold concentration is required.
Boyan
B D
BD
Department of Orthopaedics, University of Texas Health Science Center, San Antonio 78229-3900, USA. BoyanB@uthscsa.edu
Weesner
T C
TC
Lohmann
C H
CH
Andreacchio
D
D
Carnes
D L
DL
Dean
D D
DD
Cochran
D L
DL
Schwartz
Z
Z
D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects; D018786:Bone Substitutes / Q000627:therapeutic use; D016025:Bone Transplantation / Q000379:methods* / Q000473:pathology; D001842:Bone and Bones / Q000187:drug effects / Q000473:pathology; D003648:Decalcification Technique; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D005500:Follow-Up Studies; D005612:Freeze Drying; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D018482:Muscle, Skeletal / Q000473:pathology / Q000601:surgery; D010012:Osteogenesis / Q000187:drug effects*; D013552:Swine; D014021:Tissue Preservation; D014183:Transplantation, Heterologous; D014184:Transplantation, Homologous
D018786:Bone Substitutes; D003746:Dental Enamel Proteins; C109069:enamel matrix proteins