Lysophosphatidic acid modulates the regenerative responses of human gingival fibroblasts and enhances the actions of platelet-derived growth factor.
BACKGROUND
Platelet-derived growth factor (PDGF) has been used to promote healing in many in vitro and in vivo models of periodontal regeneration. PDGF is known to interact extensively with another platelet mediator, lysophosphatidic acid (LPA), to enhance regenerative responses in non-oral systems. PDGF and LPA are both liberated by platelets in the blood clot, which is known to be critical in stabilizing early periodontal wound healing. The purpose of this study was to evaluate the basic interactions of LPA with primary human gingival fibroblasts (GF) alone and with PDGF-BB for promoting GF growth and migration, as well as their effects in an in vitro oral wound-healing model.


METHODS
GF regenerative responses were measured using 1 and 10 microM LPA in the absence or presence of 1 or 10 ng/ml PDGF-BB. Cell growth was determined using [3H]thymidine incorporation and cell counting. Migration responses were measured using a microchemotaxis chamber. For the in vitro wound-healing experiments, GF were grown to confluence on glass slides, and a 3 mm wide wound was mechanically inflicted. Percent wound fill on days 4, 6, and 9 was analyzed using computer-assisted histomorphometry.


RESULTS
GF exhibited proliferative and chemotactic responses to LPA. These responses were synergistic when LPA and PDGF-BB were present together. LPA on its own did not stimulate statistically significant wound fill, but when combined with PDGF-BB, wound fill was equivalent to the 10% serum positive control group by day 6 (5.5-fold of negative control, [P<0.001]) and again on day 9 (6-fold of negative control, [P<0.001]).


CONCLUSIONS
These studies provide the first evidence that LPA stimulates human GF regenerative responses and that it interacts positively with PDGF-BB to regulate these actions. The results suggest that LPA needs to be further investigated in the oral system as a factor that should be considered for incorporation when designing new periodontal wound-healing therapies using PDGF.
Cerutis
D Roselyn
DR
Department of Oral Biology, Creighton University, School of Dentistry, Omaha, NE 68178, USA. rcerutis@creighton.edu
Dreyer
Andrew
A
Cordini
Franco
F
McVaney
Timothy P
TP
Mattson
John S
JS
Parrish
Lawrence C
LC
Romito
Laura
L
Huebner
Gene R
GR
Jabro
Mansoor
M
D000077214:Becaplermin; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002633:Chemotaxis / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects*; D005881:Gingiva / Q000187:drug effects*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008246:Lysophospholipids / Q000494:pharmacology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis; D011994:Recombinant Proteins; D012038:Regeneration / Q000187:drug effects; D014945:Wound Healing / Q000187:drug effects
D008246:Lysophospholipids; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D011994:Recombinant Proteins; D000077214:Becaplermin; C032881:lysophosphatidic acid