THE ROLE OF TRANSFORMING GROWTH-FACTOR-BE TA-1 (TGF-BETA-1) AND OF VASCULAR ENDOTHELIAL GROWTH-FACTOR (VEGF) ON THE IN-VITRO ANGIOGENESIS PROCESS

We have studied the role of 2 exogenous cytokines, the TGF-beta 1 and the VEGF, on the in vitro angiogenesis process. Endothelial cells were plated on fibrin matrices either with 2% or with 10% human serum in 1 99 medium. Forty-eight hours later, with 10% human serum, the capillar y-like network index (the percentage of the culture area covered by th e capillary network) was about 50%. Under these culture conditions, wh en TGF-beta 1 or VEGF were added, the capillary-like network index aug mented and was nearing 75%. When the index is high, using confocal mic roscopy, we show that hollow capillaries are formed. Moreover, the add ition of VEGF increased the kinetics of the capillary-like network for mation. With 2% human serum, 48 h after seeding, the capillary-like ne twork index was about 75%. In this case, the addition of TGF-beta 1 de creased the network index, whereas the addition VEGF increased the kin etics of its formation. These in vitro angiogenesis experiments show t hat the serological factors underline the 2 antagonist effects of TGF- beta 1, but have no detectable effects on the activator effects of the VEGF.