Influence of different calcium phosphate ceramics on growth and differentiation of cells in osteoblast-endothelial co-cultures.

Strategies for improvement of angiogenesis and vasculogenesis using different cells and materials are paramount aims in the field of bone tissue engineering. Thereby, the interaction between different cell types and scaffold materials is crucial for growth, differentiation, and long-term outcomes of tissue-engineered constructs. In this study, we evaluated the interaction of osteoblasts and endothelial cells in three-dimensional tissue-engineered constructs using beta tricalciumphosphate (β-TCP, [ß-Ca3 (PO4 )2 ]) and calcium-deficient hydroxyapatite (CDHA, [Ca9 (PO4 )5 (HPO4 )OH]) ceramics as scaffolds. We focused on initial cell organization, cell proliferation, and differential expression of osteoblastic and endothelial markers employing monocultures and co-cultures of endothelial cells of two different origins [human umbilical vein endothelial cells (HUVECs) and outgrowth endothelial cells (OECs)] with primary human osteoblasts (hOBs). Despite different chemical and physical characteristics of CDHA and β-TCP ceramics, similar patterns in cell growth, differentiation, and gene expression were detected in tissue-engineered constructs consisting of hOB, HUVEC, and HUVEC/hOB-co-cultures. Under dynamic cell culture conditions we found proliferation of these cells with stable endothelial and osteoblastic differentiation patterns. Both material types are highly biocompatible with these cells providing a promising perspective for the future research. In this study, both materials did not support growth and differentiation of OEC.