Biological effects of cementum and bone extracts on human periodontal fibroblasts.
BACKGROUND
Non-collagenous proteins of mineralized tissues play important roles in bone induction during mineralization and in regulating the activity of many types of mesenchymal cells. This study was conducted to determine the effects of acetic acid extracts of bone and cementum on alkaline phosphatase (ALPase) activity and in vitro mineralization of cultured human periodontal fibroblasts (hPF).


METHODS
Alveolar bone and cementum obtained from clinically healthy subjects were extracted by a solution containing 0.5 M acetic acid and enzyme inhibitors. Osteoblastic phenotypes of hPF were assayed by ALPase activity, gene expression of bone marker proteins, and the ability to produce in vitro mineralization in culture media containing 50 microg/ml ascorbic acid, 10 mM sodium beta-glycerophosphate, and 10(-7) M dexamethasone. The effects of cementum and bone extracts on the expression of osteoblastic phenotypes in hPF were also determined.


RESULTS
Many protein components, varying in molecular weight from 10 to 14 to 120 kDa, were detectable in 10% SDS-PAGE of both cementum and alveolar bone extracts. The hPF cells were found to exhibit a moderate ALPase activity when compared with rat osteosarcoma (ROS) 17/2.8 cells under the same experimental conditions. Gene expression for ALPase, osteocalcin bone sialoprotein, osteopontin, and BMP-7 at mRNA message was detected by RT-PCR in hPF and ROS 17/2.8 cells. The confluent hPF and ROS 17/2.8 cells showed evidence of calcium deposition in the extracellular milieu at 30 and 15 to 30 days' cultures, respectively, under a mineralization medium. The hPF appeared to form mineralized foci with morphological characteristics different from the mineralized nodules produced by ROS 17/2.8 cells. The addition of low concentrations (5 microg/ml) of either cementum or bone extract produced an increase in the size and number of mineralization spots, as well as greater ALPase activity in both hPF and ROS 17/2.8 cultures during the observation periods.


CONCLUSIONS
These results suggest that hPF possess certain mineralizing phenotypes, and that acetic acid extracts of bone and cementum contain components capable of stimulating osteogenic differentiation of hPF.
Hou
L T
LT
Department of Periodontology, School of Dentistry, National Taiwan University, Taipei. lthou@ha.mc.ntu.edu.tw
Liu
C M
CM
Lei
J Y
JY
Wong
M Y
MY
Chen
J K
JK
D019342:Acetic Acid / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001857:Bone Matrix / Q000737:chemistry / Q000378:metabolism*; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis; D002113:Calcification, Physiologic / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D016009:Chi-Square Distribution; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003739:Dental Cementum / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D058574:Integrin-Binding Sialoprotein; D015675:Osteocalcin / Q000096:biosynthesis; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics; D053495:Osteopontin; D012516:Osteosarcoma; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D012038:Regeneration / Q000187:drug effects* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000096:biosynthesis; D014020:Tissue Extracts / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D019485:Bone Morphogenetic Proteins; D017077:Culture Media, Conditioned; C546871:IBSP protein, human; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D014020:Tissue Extracts; D015675:Osteocalcin; D053495:Osteopontin; D000469:Alkaline Phosphatase; D019342:Acetic Acid