Design of a co-culture system using collagen microthreads to facilitate neovascularization

Several co-culture systems incorporating fibroblasts and endothelial cells have been used to characterize cell-cell and cell-matrix interactions critical for angiogenesis. However, these models do not provide a means for translation to clinical application. Here, we develop an approach that may facilitate in vivo neovascularization utilizing the advantages of both proangiogenic co-culture and collagen microthreads. This system could also serve as an in vitro tool to study angiogenic mechanisms. Self-assembled collagen microthreads populated with human dermal fibroblasts (HDFs) were extruded using a novel method. Human umbilical vein endothelial cells (HUVECs) were then seeded on the surface of the HDF-populated collagen microthreads. Fluorescence microscopy confirmed the presence of both cell types after 24 hours of co-culture and phalloidin staining was used to visualize cell morphology. These results demonstrate that co-cultures can be established using a collagen microthread platform, which may ultimately allow concurrent delivery of two therapeutic cell types.