GM-CSF reduces hBMVEC death induced by cytokines.

<p><b>a</b>. hBMVEC were exposed to T&I in the presence of GM-CSF (20 ng/ml) either alone or in combination with S1P (50 nM). The protection induced by the growth factor was significantly increased over S1P alone, whereas the combination of the two induced an effect comparable to GM-CSF alone. *p< 0.05 vs T&I, # p<0.05 T&I+S1P. <b>b</b> Exposure to GM-CSF (20 ng/ml or 0.1 ng/ml) was able to counteract T&I induced hBMVEC death. The effect of the growth factor was comparable to the effect of pFTY (50 nM). When the two compounds were used in combination, their effect was less than additive. <b>c-d</b>. When astrocytes conditioned medium (ACM), derived from hAST treated with S1P (c) or pFTY (d), was transferred to hBMVECs in combination with a neutralizing antibody against GM-CSF (1 μg/ml), the protective effect of GM-CSF was abolished, as demonstrated by increased hBMVEC death. Data are the mean ±S.E.M. of three independent experiments, each run in triplicate, in which three to five fields per well were counted.*p< 0.05 vs T&I, # p<0.05 vs the respective treatment in absence of the neutralizing antibody.