Platelet-rich plasma provides nucleus for mineralization in cultures of partially differentiated periodontal ligament cells.
Platelet-rich plasma (PRP) has been used to promote periodontal regeneration following the premise that constituent transforming growth factor-beta1 (TGF-beta1) and platelet-derived growth factor-AB will stimulate cell proliferation at the site of application. In previous studies, we demonstrated that PRP mimics TGF-beta1 to modulate proliferation in a cell type- specific manner, that fibrin clot formation by PRP upregulates type I collagen, and that an unidentified factor(s) in PRP increases alkaline phosphatase (ALP) activity in human periodontal ligament (PDL) cell cultures. We have now examined the effects of PRP on in vitro mineralization. Platelet-rich plasma and PDL cells were prepared from human adult volunteers or rats. After 20 d of continuous treatment with PRP in dexamethazone (Dex)-containing osteogenic medium, PRP time dependently promoted mineralization by rat PDL cells but failed to fully induce the osteoblastic phenotype. Furthermore, when human PDL cells were induced to increase ALP activity in osteogenic medium that lacked Dex, a condition that should delay (or suppress) osteoblastic differentiation, transmission electron microscopy revealed that mineralized spicules were initially deposited onto PRP-derived platelet aggregates. Taken together with our previous data, these findings suggest that PRP provides platelet aggregates as nuclei to initiate mineralization while stimulating PDL cell proliferation, differentiation, and collagen production. The combination of these effects may effectively mediate PRP's ability to promote regeneration of periodontal tissue, including skeletal tissue, at the site of injury.
Kawase
Tomoyuki
T
Division of Cellular Pharmacology, Department of Signal Transduction Research, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan. kawase@dent.niigata-u.ac.jp
Okuda
Kazuhiro
K
Saito
Yoshinori
Y
Amizuka
Norio
N
Suzuki
Hironobu
H
Yoshie
Hiromasa
H
D000328:Adult; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology*; D002113:Calcification, Physiologic / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D017931:DNA Primers; D006801:Humans; D046529:Microscopy, Electron, Transmission; D010006:Osteoblasts / Q000166:cytology*; D010513:Periodontal Ligament / Q000502:physiology* / Q000648:ultrastructure; D051381:Rats; D011917:Rats, Inbred Lew; D012038:Regeneration / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D000469:Alkaline Phosphatase