Background: We have previously shown that cultured human periodontal ligament (HPL) cells produce nerve growth factor (NGF) and express mRNA of tyrosine kinase receptor (trkA), a high-affinity receptor of NGF. These findings suggest that NGF modulates the differentiation and proliferation of the periodontal ligament cells by paracrine and autocrine functions in vivo. Endothelial cells also express NGF and trkA. Therefore, NGF may regulate functions of periodontal ligament cells and endothelial cells during periodontal tissue regeneration.
Methods: Effects of NGF on expressions of bone/cementum-related proteins (osteocalcin [OC], bone sialoprotein [BSP], bone morphogenetic protein [BMP-7], core binding factor alpha [Cbfa-1], and type I collagen), calcification in HPL cells, and proliferation and mRNA expression of vascular endothelial growth factor (VEGF), an endothelial cell mitogen, in human microvascular endothelial cells (HMVECs) were examined.
Results: NGF elevated mRNA levels of OC, BSP, BMP-7, Cbfa-1, and type I collagen and enhanced mineral deposition in cultures of HPL cells. Furthermore, NGF stimulated mRNA expressions of VEGF-A and VEGF-B and cell proliferation in HMVEC.
Conclusion: These findings suggest that the functional regulation of periodontal ligament cells and endothelial cells by NGF might result in the acceleration of periodontal tissue regeneration in vivo.