Primary human endothelial cells (HUVEC) were obtained from the veins of human umbilical cords of 3 healthy donors, as described before [23 (link)]. The experimental design was approved by the Ethics Committee of the Faculty of Medicine, University of Muenster. Written informed consent was obtained from all donors. Cells were cultivated in endothelial cell medium (C2210, PromoCell, Heidelberg, Germany) with the addition of 100 U/ml penicillin and 100 μg/ml streptavidin (both from Biochrom, Berlin, Germany).
Vascular smooth muscle cells (vSMC) from the coronary artery were purchased (Lonza, Cologne, Germany) and cultured in DMEM with 4.5 g/l glucose, 10% fetal bovine serum, 2 mM L-glutamine, 1 mM sodium-pyruvate, 100 U/ml penicillin, and 100 μg/ml streptavidin (Biochrom).
Fibroblasts (CCD-32Sk) were acquired from the American Type Culture Collection (ATCC, Manassas, VA, USA) and cultivated the same as vSMCs.
Immediately before reaching a confluent monolayer, cells were detached with trypsin (Biochrom). For the experiment, cells of the 2nd and 3rd passage were seeded onto 96-well plates at a cell density of 1×105 cells/cm2.