Jarvie Journal - College of Dental Medicine - Columbia University

Volume 56, Spring 2013
Effects of Platelet Derived Growth Factor (PDGF) on Dental Sac Cell
Migration and Differentiation
Ashley Seals, Jian Zhou, Mo Chen, Jeremy J. Mao*
¹College of Dental Medicine, Columbia University, NY, NY; * Faculty Mentor
Introduction: GEM 21S® (Osteohealth) Growth-factor Enhanced Matrix, a dental device with
highly purified recombinant human platelet-derived growth factor (rhPDGF-BB) and an
osteoconductive matrix (beta tricalcium phosphate, β-TCP), is used by clinicians to regenerate
periodontal tissues. Extensive animal and clinical studies have demonstrated that PDGF is a
broad acting growth factor with chemotactic effects on osteoblasts, cementoblasts and
fibroblasts. These cells are derived from the dental sac which contains stem/progenitor cells that
can differentiate into alveolar bone, cementum, and periodontal ligament. In the presented work,
we investigated the migratory effects of PDGF on the dental sac stem/progenitor cells.
Objective: The aim of this study is to compare the migratory effect of Emdogain®
(Straumann), BMP-4, BMP-7, TGF-β and rhPDGF-BB on rat dental sac cells.
Materials and Methods: Dental sac cells were isolated from 7 day old Sprague Dawley-rats
and were propagated in DMEM containing 10% FBS, 1% antibiotics. The cells were further
characterized using colony forming assay. Briefly, 50 dental sac cells were seeded in 3 cm
diameter dish and cultured for 2 weeks. After fixation, the cells were stained with crystal violet.
Colonies larger than 2 mm were counted. The cells were also examined for osteogenic
differentiation. Cells with 80% confluence were cultured in osteogenic induction medium (5mM
beta-glycerophosphate, 50ng/ml Ascorbic acid, and 10 -6 M dexamethasone). Medium was
changed 2 times per week. After 3 weeks, cell differentiation was examined using Alkaline
Phosphatase (ALP) staining and von Kossa staining. Cell migration was tested using Boyden
Chamber assay. Boyden chamber inserts with 8µm pores were seeded with 1 x 10 5 dental sac
cells and placed in wells containing the following solutions: 1% FBS, 10% FBS, 30% FBS, and
Emdogain, BMP-4, BMP-7, TGF-β and PDGF at various concentrations (10, 50, 100 ng/ml).
Cells were allowed to migrate for 12 hours, detached from the chamber barriers with 0.25%
trypsin, and then counted.
Results and conclusion: 1) The dental sac contains stem/progenitor cells. In vitro, dental sac
cells display spindle shape morphology, can form colonies, and can differentiate into osteoblasts
as demonstrated by the ALP staining and von Kossa staining. 2) PDGF promotes dental sac cell
migration. 10 ng/ml PDGF induced almost 40% dental sac cell migration, while 50ng/ml
induced over 80% migration. Both ratios are much higher than the result of 30% FBS group
(30% migratory cells), which was used as positive control in this study. Other factors, BMPs,
Emdogain and TGF-β, did not show dramatic chemotactic effects.
Discussion: In this study, we compared the chemotactic effect of PDGF to other clinical drug
and osteoinductive factors. Among the migratory cues examined in this study, PDGF is the most
potent chemotactic factor, which may partially contribute to the therapeutic effect of GEM-21S.
This study is sponsored by a NIH grant awarded to JJ Mao.
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