Structural and functional macrophages alterations by ceramics of differentcomposition

Biomaterials may initiate several and complex biological reactions in host tissues, and the cell-biomaterial interactions can determine the release of mediators including monocytes and lymphocytes chemotactic factors. The pre sent work was aimed to investigate in vitro the macrophage biological react ions of a natural apatite obtained by heat treatment at 400 degrees C of bo vine bone, compared to other ceramics usually used for dental and orthopedi c applications, using synthetic apatite and three types of alumina as contr ols. Particles chemotactic activity and powders oxidative burst evidenced n o monocyte-macrophages sensitivity reaction for natural and synthetic hydro xyapatite powders at great granulometry (> 50 mu m); data were confirmed by ultrastructural observations; electron microscopy analysis showed macropha ges with the features of healthy cells in the presence of both natural and synthetic apatites while macrophages grown in the presence of alumina seeme d to be negatively affected. In conclusion, among all ceramics tested, natu ral apatite displayed a good compatibility with living cells, bring better tolerated than synthetic hydroxyapatite which in turn is better tolerated t han alumina. (C) 1999 Elsevier Science Ltd. All rights reserved.