Endothelial cell migration, adhesion and proliferation on different polymeric substrates

BACKGROUND: The formation of a functionally-confluent endothelial cell (EC) monolayer affords proliferation of EC, which only happens in case of appropriate migratory activity. AIM OF THE STUDY: The migratory pathway of human umbilical endothelial cells (HUVEC) was investigated on different polymeric substrates. MATERIAL AND METHODS: Surface characterization of the polymers was performed by contact angle measurements and atomic force microscopy under wet conditions. 30,000 HUVEC per well were seeded on polytetrafluoroethylene (PTFE) (θ adv =119°±2°), on low-attachment plate LAP (θ adv =28°±2°) and on polystyrene based tissue culture plates (TCP, θ adv =22°±1°). HUVEC tracks (trajectories) were recorded by time lapse microscopy and the euclidean distance (straight line between starting and end point), the total distance and the velocities of HUVEC not leaving the vision field were determined. RESULTS: On PTFE, 42 HUVEC were in the vision field directly after seeding. The mean length of single migration steps (SML) was 6.1±5.2 μm, the mean velocity (MV) 0.40±0.3 μm·min -1 and the complete length of the trajectory (LT) was 710±440 μm. On TCP 82 HUVEC were in the vision field subsequent to seeding. The LT was 840±550 μm, the SML 6.1±5.2 μm and the MV 0.44±0.3 μm·min -1. The trajectories on LAP differed significantly in respect to SML (2.4±3.9 μm, p<0.05), the MV (0.16±0.3 μm·min -1, p<0.05) and the LT (410±300 μm, p<0.05), compared to PTFE and TCP. Solely on TCP a nearly confluent EC monolayer developed after three days. While on TCP diffuse signals of vinculin were found over the whole basal cell surface organizing the binding of the cells by focal adhesions, on PTFE vinculin was merely arranged at the cell rims, and on the hydrophilic material (LAP) no focal adhesions were found. CONCLUSION: The study revealed that the wettability of polymers affected not only the initial adherence but also the migration of EC, which is of importance for the proliferation and ultimately the endothelialization of polymer-based biomaterials.