Stimulation of monocytes and macrophages: Possible influence of surface roughness

Issue title: Selected Proceedings of the 14th European Conference for Clinical Hemorheology and Microcirculation, Dresden, Germany, June 27–30, 2007

Article type: Research Article

Authors: Fink, J.^; | Fuhrmann, R. | Scharnweber, T. | Franke, R.P.^;

Affiliations: Central Institute for Biomedical Engineering, Department for Biomaterials, University of Ulm, Ulm, Germany | Institute for Biological Interfaces, Forschungszentrum Karlsruhe GmbH, Karlsruhe, Germany | Berlin Brandenburg Center for Regenerative Tissue, Teltow, Berlin, Germany

Note: [] Corresponding author: Dr. Jochen Fink, University of Ulm, ZBMT, Department of Biomaterials, Albert-Einstein-Allee 47, D-89081 Ulm, Germany. Tel.: +49 731 5025362; Fax: +49 731 502 5348; E-mail: [email protected].

Abstract: The aim of this study was to understand the mechanisms of interaction of monocytes/macrophages and foreign body giant cell (FBGC) with implant materials, with respect to the roughness and the solubility of calcium phosphate based coatings. Anderson et al. (Bone Engineering, J.E. Davies, ed., Toronto, 2000, pp. 81–93) showed that the presence of FBGC's and monocytes/macrophages influenced the strength of the implant-tissue integration and that more monocytes/macrophages rested on smooth surfaces compared to rough surfaces. We seeded human bone marrow cells on uncoated ultrasmooth polished TiAl6V4 samples as well as on coated TiAl6V4 discs of the same diameter with two different calcium phosphates coatings, monetite (DCP) and hydroxyapatite (OHAp), both with rougher surfaces. On uncoated ultrasmooth polished TiAl6V4 discs (UUTi, diameter 16 mm, thickness 2 mm) and on TiAl6V4 discs of same diameter coated with OHAP or DCPA, human bone marrow cells (HMBC) were seeded and cultivated under standard culture conditions for 90 days without addition of inducing substances like ascorbic acid, Na-β-glycerophosphate or dexamethasone. The roughnesses of the virgin samples were assessed with atomic force microscopy and light profilometry. After 90 days of cultivation a fraction of the samples, with cells and extracellular matrix, were stained with hematoxylin eosin (HE) and examined in light microscopy. Ra roughness values of virgin uncoated TiAl6V4 samples were 0.001 μm, of DCP coated discs 4 μm and of OHAp coated discs 3 μm. The examination of HE stained samples showed a high number of FBGC and monocytes/macrophages on the UUTi samples. On the DCP coated samples there were less FBGC and monocytes/macrophages and on the OHAp coated samples we could not find any FBGC and monocytes/macrophages. The extracellular matrix (ECM) we found on the UUTi samples was finer and thinner than on the coated samples. The ECM was vastly spread and not dense on the UUTi samples in contrast to the calcium phosphate coated samples, where the ECM was much thicker and stronger. The ultrasmooth surface of the uncoated TiAl6V4 samples, a material which is accepted to be biocompatible, evidently induced the differentiation of cells of the monocytic lineage and the formation of FBGC out of the cell populations present in the human bone marrow.

Keywords: Calcium phosphate, monocytes, macrophages, foreign body giant cells, stimulation

DOI: 10.3233/CH-2008-1090

Journal: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 205-212, 2008