Comparative effects of platelet-derived growth factor-BB and insulin-like growth factor-I, individually and in combination, on periodontal regeneration in Macaca fascicularis

Platelet-derived growth factor (PDGF) and insulin-like growth factor I (IGF-I) in combination have previously been shown to enhance periodontal regeneration. The objective of this study was to further characterize the biological effects of this combination of growth factors in non-human primates and compare the effects to those of each growth factor individually. Ligature-induced periodontitis was initiated in 10 cynomolgus monkeys, After periodontal lesions were established, surgery was performed, and either a methylcellulose gel vehicle or vehicle containing 10 mu g each of either PDGF-BB, IGF-I or both PDGF-BB and IGF-I was applied to exposed root surfaces. Biopsies were taken 4 and 12 wk after treatment and the extent of periodontal regeneration was assessed by histomorphometry, At both 4 and 12 wk vehicle-treated lesions generally revealed minimal osseous defect fill (ODF) (8.5+/-2.1% and 14.5+/-5.7%, respectively) and new attachment (NA) (34.1+/-5.2% and 26.6+/-10.5%, respectively), IGF-I treatment did not significantly alter healing compared to vehicle in any parameter at both 4 and 12 wk, PDGF-BB-treated sites exhibited significant (p<0.05) regeneration of NA (69.6+/-12.0%) at 12 wk; trends for PDGF-BB treatment effect were also observed in other parameters at 4 and 12 wk, although these increases were not statistically significant. Treatment with PDGF-BB/IGF-I resulted in 21.6+/-5.1% and 42.5+/-8.3% ODF at 4 and 12 wk, respectively, and 64.1+/-7.7% and 74.6+/-7.4% NA at 4 and 12 wk, respectively (all significantly greater than vehicle, p<0.05), The results from this study demonstrated that: 1) IGF-I alone at the dose tested did not significantly alter periodontal wound healing; 2) PDGF-BB alone significantly stimulated NA, with trends of effect on other parameters; and 3) the PDGF-BB/IGF-I combination resulted in significant increases in NA and ODF above vehicle at both 4 and 12 wk.