Effects of Culture Supernatants of Leukocytes from Periodontal Patients on Monocyte-Mediated Hydroxyapatite Resorption

¹ Department of Periodontology, Meikai University, School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 350-02, Japan

In this study, the effects of culture supernatants on various activities of the monocyte, as a bone-resorbing cell, were compared between peripheral blood leukocyte (PBL) cultures from patients with periodontal disease and those from subjects with a clinically healthy periodontium. We have reported that normal human monocytes in vitro induce the release of calcium from synthetic hydroxyapatite particles and that the activity is enhanced by supernatants from cultures of stimulated or non-stimulated peripheral blood leukocytes.

Monocytes from both patients and healthy subjects induced the release of calcium from hydroxyapatite particles (HA) to an equal degree. This activity of monocytes from healthy subjects showed a statistically significant increase by addition of supernatants from stimulated or unstimulated cultures of peripheral blood leukocytes from periodontitis patients. This increase was greater than that seen with supernatants from cells of healthy controls. The Nitro Blue Tetrazolium reduction activity and [³H]-thymidine incorporation of monocytes were also increased by addition of the supernatants from leukocyte cultures from either patients or healthy controls, but no significant difference was noted in the increase.

These results suggest that the HA-resorbing activity of monocytes was enhanced by factors from cultured leukocytes. Furthermore, these studies showed that production of these factors by peripheral mononuclear cells from patients with periodontal disease was greater than that seen with cells from normal subjects.