Quantification and localization of platelet-derived growth factor in gingiva of periodontitis patients.
BACKGROUND
Platelet-derived growth factor (PDGF) is a mitogen and chemoattractant for cells of mesenchymal origin. Over-expression of PDGF-B can promote formation of inflammatory lesions in the lungs of transgenic mice. Moreover, continuous exposure to PDGF inhibits collagen production by osteoblastic cells. Thus, the expression of mitogenic factors in an inflammatory context may limit the differentiated function of cells, and thereby limit repair following periodontal attachment and bone loss. The goals of the present study were to test whether PDGF is present at increased levels in inflamed gingiva and to localize its expression in gingival biopsies from individuals with chronic periodontitis.


METHODS
Tissues obtained during therapeutic procedures from inflamed and control sites of 9 patients were subjected to protein extraction, descriptive histology by hematoxylin and eosin, or immunohistochemistry assays. Quantification was calculated with an enzyme-linked immunosorbent assay (ELISA) kit specific for PDGF-AB. For the immunolocalization, anti-PDGF-A and -B antibodies were employed.


RESULTS
PDGF concentration in the total protein extract was approximately 3 times higher in the inflamed sites (0.60 +/- 0.18 ng/mg versus 0.20 +/- 0.05 ng/mg; P = 0.03). Immunohistochemistry revealed prominent expression of PDGF in the pocket epithelial cells as well as the adjacent connective tissue. In contrast, little or no expression was detected in control biopsies devoid of the pocket epithelium and granulation tissue.


CONCLUSIONS
PDGF is present in increased levels in the human inflamed gingiva and is mainly localized to the pocket epithelium. It is possible that chronic expression of PDGF contributes to the inflammatory changes that occur during periodontal diseases.
Pinheiro
Maria Leticia B
ML
Graduate Periodontics, Faculdade de Odontologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Feres-Filho
Eduardo J
EJ
Graves
Dana T
DT
Takiya
Christina M
CM
Elsas
Maria Ignez G
MI
Elsas
Pedro Paulo
PP
Luz
Ricardo A
RA
D000328:Adult; D000368:Aged; D000906:Antibodies; D002908:Chronic Disease; D004396:Coloring Agents; D003238:Connective Tissue / Q000378:metabolism / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005260:Female; D005881:Gingiva / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D010514:Periodontal Pocket / Q000378:metabolism / Q000473:pathology; D010518:Periodontitis / Q000378:metabolism / Q000473:pathology*; D010982:Platelet-Derived Growth Factor / Q000032:analysis*; D011506:Proteins / Q000032:analysis
D000906:Antibodies; D004396:Coloring Agents; D010982:Platelet-Derived Growth Factor; D011506:Proteins; C095477:platelet-derived growth factor AB