Background
Increasing the complexity of in vitro systems to mimic three-dimensional tissues and the cellular interactions within them will increase the reliability of data that were previously collected with in vitro systems. In vivo vascularization is based on complex and clearly defined cell-matrix and cell-cell interactions, where the extracellular matrix (ECM) seems to play a very important role. The
Conclusion
Our results visualize the importance of the physical contact between all cellular and acellular components of the cocultures.
Methods
Quantitative and qualitative analyses during the generation of a coculture tissue construct consisting of endothelial cells and fibroblasts were done using transmission electron microscopy and immunohistochemistry.
Results
Dynamic interactions were found in cocultures between ECs, between fibroblasts (FBs), between ECs and FBs, and between the cells and the ECM. Microvesicles were involved in intercellular information transfer. FBs took an active and physical part in the angiogenesis process. The ECM deposited by the cells triggered endothelial angiogenic activity. Capillary-like tubular structures developed and matured. Moreover, some ECM assembled into a basement membrane (BM) having three different layers equivalent to those seen in vivo. Finally, the three-dimensional in vitro construct mirrored the topography of histological tissue sections.