Bone regeneration using a synthetic matrix containing a parathyroid hormone peptide combined with a grafting material.
OBJECTIVE
The aim of the present study was to test whether a newly developed synthetic matrix made of polyethylene-glycol (PEG) containing a covalently bound peptide of the parathyroid hormone (PTH1-34) enhances bone regeneration compared to grafting procedures and to spontaneous healing.


METHODS
In each of 16 rabbits used, 4 titanium cylinders were screwed into perforated slits made in the cortical bone of the calvaria. The cylinders were either left empty (control) or filled with 1 of the following: (1) PEG matrix and hydroxyapatite/tricalcium phosphate (HA/TCP) granules, (2) PEG matrix containing 100microg/mL of PTH and HA/TCP granules, or (3) PEG matrix containing 20microg/mL of PTH1-34 and HA/TCP granules. After 8 weeks, the animals were sacrificed, and ground sections were obtained for histology.


RESULTS
Quantitative histomorphometry demonstrated a significantly increased amount of newly formed bone for PTH1-34 compared to sites treated with PEG and HA/TCP and to empty control sites (P < .01; analysis of variance and subsequent pairwise Student t test). The mean percentages of mineralized bone were 19.6%+/-6.0% for 100 microg/mL PTH, 18.0% +/- 6.2% for 20microg/mL PTH, 12.0% +/-6.5% for PEG and HA/TCP without PTH, and 10.5% +/-3.7% for the empty control. The mean areas of bone regenerated within the cylinders were 53.5% +/-22.7% for 100 microg/mL PTH, 51.1% +/-22.6% for 20 microg/mL PTH, 34.3% +/- 22.5% for PEG and HA/TCP without PTH, and 23.2% +/-10.1% for the empty control.


CONCLUSIONS
Human and animal trials have demonstrated that daily systemic injection of PTH increases bone mineral density. The present study showed that local administration of PTH was also effective in stimulating bone formation.


CONCLUSIONS
It is concluded that this synthetic PEG hydrogel containing a covalently bound peptide of the PTH combined with HA/TCP granules significantly stimulated in situ bone augmentation in rabbits.
Jung
Ronald E
RE
Department of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Switzerland. jung@zzmk.unizh.ch
Hämmerle
Christoph H
CH
Kokovic
Vladimir
V
Weber
Franz E
FE
D000704:Analysis of Variance; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000494:pharmacology*; D002130:Calcium Phosphates / Q000494:pharmacology; D003545:Cysteine; D017886:Durapatite / Q000494:pharmacology; D020100:Hydrogels; D010281:Parathyroid Hormone / Q000737:chemistry / Q000494:pharmacology*; D010294:Parietal Bone / Q000601:surgery; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011817:Rabbits
D018786:Bone Substitutes; D002130:Calcium Phosphates; D020100:Hydrogels; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011092:Polyethylene Glycols; D017886:Durapatite; C018392:tricalcium phosphate; D003545:Cysteine