Induction of Growth Factor Release During Periodontal Wound Repair

Introduction: Platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) are potent tissue healing molecules involved in mitogenesis and angiogenesis. Little is known regarding the release of these growth factors into periodontal wound fluid (PWF) during healing. Objectives: This investigation examined the effect of periodontal surgery on PWF levels of PDGF and VEGF. Methods: Sixteen human subjects possessing chronic severe periodontal disease were monitored longitudinally at nine different time points. PWF was harvested with paper strips and analyzed for PDGF-AB and VEGF levels by ELISA. The sites were divided into one of three groups: 1) Periodontal surgery plus delivery of an osteoconductive beta tri-calcium phosphate device placed at an intraosseous defect (surgery + device); 2) adjacent site (s) to the target lesion that did not receive device (surgery without device); and 3) contralateral sites that did not receive surgery (non-surgical sites). Results: Periodontal flap surgery induced VEGF release into the PWF within 3-5 d post-surgery and peaked at 12-15 d, with surgery + device sites demonstrating the highest levels above controls (>6 fold induction in VEGF compared to no surgery (p<0.01) and >3 fold VEGF induction compared to surgery + no device). In contrast, PWF levels of PDGF-AB demonstrated peak activity earlier (3-5 d) with a >5 fold induction and ~2 fold induction over no surgery and surgery + no device (p <0.01) groups, respectively. Sites not receiving periodontal surgery failed to display any significant alternations in crevicular fluid growth factor levels over the 24 w observation period. Conclusion: The results reveal contrasting inducible expression patterns of PDGF and VEGF during periodontal wound healing in humans. This information provides a better understanding of wound healing growth factors that participate during the periodontal repair process. This study was supported by NIH/NIDCR Grants T-35DE07101, DE11960 and BioMimetic Pharmaceuticals, Inc.