TY - JOUR
T1 - Hypoxia stimulates human endothelial cells to release smooth muscle cell mitogens: Role of prostaglandins and bFGF
AU - Michiels, Carine
AU - De Leener, Frederic
AU - Arnould, Thierry
AU - Dieu, Marc
AU - Remacle, José
PY - 1994
Y1 - 1994
N2 - Abnormal smooth muscle cell (SMC) proliferation is observed in several pathological situations such as atherosclerosis, pulmonary hypertension, and venous pathologies, resulting in a thickening of the vessel wall. If endothelial cells have been assumed to play a role in the triggering of this proliferation, no direct evidence is available. As ischemia is often linked to these situations, we exposed human umbilical vein endothelial cells (HUVEC) to hypoxia. The HUVEC-conditioned medium was then added to SMC and the proliferation of these cells was measured. We observed a pro- proliferative activity for SMC of the hypoxic HUVEC-conditioned medium but not of the normoxic HUVEC one. This pro-proliferative activity could not be inhibited if HUVEC were treated with cycloheximide but was blocked if the synthesis of prostaglandins by HUVEC was inhibited during hypoxia. PGD2, and especially PGF(2α) at the concentration found in the hypoxic HUVEC- conditioned medium, were demonstrated to have a mitogenic effect on SMC. PGE2 also showed a pro-proliferative activity but at higher concentrations. In addition, the kinetics of increase in SMC proliferation induced by a mixture of the four prostaglandins at the corresponding concentrations was the same as the one observed with hypoxic HUVEC-conditioned medium. However, when tested on fibroblasts which do not respond to PGF(2α), hypoxic HUVEC- conditioned medium also had a pro-proliferative activity. In addition, anti- bFGF antibodies but not anti-PDGF blocked the mitogenic activity of this conditioned medium for SMC. Finally, the mitogenic effects of PGF(2α) and of bFGF on SMC are additive. These results indicate that bFGF is probably also involved. These results indicate that these prostaglandins act in synergy with bFGF and are the molecules responsible for the pro-proliferative activity observed in hypoxic HUVEC-conditioned medium. We propose that these findings can explain the excessive growth of SMC in blood vessels following chronic ischemic situations.
AB - Abnormal smooth muscle cell (SMC) proliferation is observed in several pathological situations such as atherosclerosis, pulmonary hypertension, and venous pathologies, resulting in a thickening of the vessel wall. If endothelial cells have been assumed to play a role in the triggering of this proliferation, no direct evidence is available. As ischemia is often linked to these situations, we exposed human umbilical vein endothelial cells (HUVEC) to hypoxia. The HUVEC-conditioned medium was then added to SMC and the proliferation of these cells was measured. We observed a pro- proliferative activity for SMC of the hypoxic HUVEC-conditioned medium but not of the normoxic HUVEC one. This pro-proliferative activity could not be inhibited if HUVEC were treated with cycloheximide but was blocked if the synthesis of prostaglandins by HUVEC was inhibited during hypoxia. PGD2, and especially PGF(2α) at the concentration found in the hypoxic HUVEC- conditioned medium, were demonstrated to have a mitogenic effect on SMC. PGE2 also showed a pro-proliferative activity but at higher concentrations. In addition, the kinetics of increase in SMC proliferation induced by a mixture of the four prostaglandins at the corresponding concentrations was the same as the one observed with hypoxic HUVEC-conditioned medium. However, when tested on fibroblasts which do not respond to PGF(2α), hypoxic HUVEC- conditioned medium also had a pro-proliferative activity. In addition, anti- bFGF antibodies but not anti-PDGF blocked the mitogenic activity of this conditioned medium for SMC. Finally, the mitogenic effects of PGF(2α) and of bFGF on SMC are additive. These results indicate that bFGF is probably also involved. These results indicate that these prostaglandins act in synergy with bFGF and are the molecules responsible for the pro-proliferative activity observed in hypoxic HUVEC-conditioned medium. We propose that these findings can explain the excessive growth of SMC in blood vessels following chronic ischemic situations.
UR - http://www.scopus.com/inward/record.url?scp=0028228645&partnerID=8YFLogxK
U2 - 10.1006/excr.1994.1171
DO - 10.1006/excr.1994.1171
M3 - Article
C2 - 8020605
VL - 213
SP - 43
EP - 54
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 1
ER -