Stimulation of DNA synthesis by endothelin-1 in primary cultures of human dental pulp

Abstract

Endothelin (ET), besides being a powerful vasoactive agent, acts as a mitogen in some cell types. ET-like immunoreactivity has been recently detected by immunocytochemistry in the vascular endothelium of human tooth germ and dental pulp, thus providing evidence for local ET production in these tissues. The effects of ET-1 on DNA synthesis in primary cultures of human dental pulp were now investigated. DNA synthesis was evaluated by flow cytometric assay and by 5-bromo,2'deoxyuridine incorporation as detected by immunocytochemistry. Cultured cells were morphologically similar to dental pulp cells and displayed vimentin immunoreactivity. Incubation of cultures with ET-1 resulted in a dose-dependent increase in the number of S-phase-traversing cells over control (unstimulated) cultures. Control skin fibroblasts were also responsive to ET. This finding raises the possibility that the multifunctional peptide ET-1 might subserve growth-promoting activity in the human tooth. It is tentatively suggested that such as an activity might be important during tooth development and in pulp inflammation and healing.