Formation of capillarylike tubular structures in a purified fibrin matrix depends on plasmin activity and not MMP activity.
hMVECs were cultured on top of a 3-dimensional matrix containing M199 supplemented with 10% human serum (HS) and 10% NBCS and stimulated with 10 ng/mL bFGF and 10 ng/mL TNF-α (bFGF/TNF-α) or 50 ng/mL VEGF165 and 10 ng/mL TNF-α (VEGF/TNF-α) in the presence (+ plasminogen) or absence of plasminogen (− plasminogen) with or without (no add) the addition of a blocking polyclonal antibody against u-PA (100 μg/mL), a blocking monoclonal antibody against u-PAR (10 μg/mL), aprotinin (aprot; 100 U/mL), or BB94 (10 μg/mL). After 4 days of culturing, total tube length was measured as described and expressed as percentage of tube length formed by bFGF/TNF-α-stimulated hMVECs or VEGF165/TNF-α-stimulated hMVECs. The data are expressed as mean ± SD of 4 to 17 experiments.
