Vascular Endothelial Growth Factor Is The Impact Of Pregnancy Induced Hypertension

Objective To find out the role of vascular endothelial growth factor in the genesis of pregnancy-induced hypertension( PIH). Methods 51 women with PIH ,44 normal pregnant women including 23 third trimester gestational ones and 10 healthy non-pregnant women were investigated. Serum concentrations of VEGF were evaluated by Elisa. Expression of VEGF and its receptors FLT-1 in placental villi were measured by immunohistochemistry. The concentrations of NO in placental tissues were assayed by nitrite reductase. Results 1. Serum levels of VEGF were lower in PIH group(23.39±9.79)ng/L when compared with that in third trimester pregnancy(40.62±14.85)ng/L, P<0.01, but they showed no difference between the mild PIH (33.79±5.97) ng/L and the third trimester, P>0.05.VEGF levels in moderate and severe PIH (21.44±2.07)ng/L,(16.45±5.56)ng/L were significantly lower than that in the group of normal term pregnancy, P<0.01. 2. In normal term placenta, VEGF-like immunoreactivity was demonstrated in the syncytiotrophoblast surrounding some villi. The expression of FLT-1 in normal term placenta was localized in the syncytiotrophoblast, mecenchyme and vascular endothelial cells. In PIH group, the distribution of VEGF and FLT-1 immunoreactivity were similar to that of normal term group, but their intensity was significantly reduced by quatitive analysis, P<0.05. 3. In PIH group, the concentrations of NO in placental tissues(11.01±6.86)umol/g were significantly lower than that in normal term placenta (19.92±10.36) umol/g, P<0.01. They showed no statistical significance between the mild PIH (18.11±7.90) umol/g and the third trimester group , P>0.05. The concentrations of NO in moderate and severe PIH (9.80±2.34)umol/g,(6.17±2.44)umol/g were significantly lower than that in normal term pregnancy, P<0.01. 4. There was a positive correlation between serum VEGF levels and the concentrations of NO in placental tissues. r=0.59, P<0.01. Conclusions The changes of VEGF levels might play an important role in the pathogenesis of PIH, and VEGF also could induce the occurrence of PIH through affecting the synthesis of nitric oxide in placental tissues.