[Expression of hypoxia-inducible factor-1alpha, vascular endothelial growth factor and sFlt-1 in preeclampsia placenta]

Abstract

Objective: To investigate the expression and correlation of hypoxia-inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF) and sFlt-1 in the preeclampsia placenta, and discuss their significance in the pathogenesis of preeclampsia.

Methods: Placentas were collected from 20 pregnant women with preeclampsia as study group and 15 normal pregnant women as control group. The expressions of HIF-1alpha, VEGF and sFlt-1 protein were semi-quantitatively analyzed with immunohistochemical assay and mRNA level was determined using reverse transcription polymerase chain reaction (RT-PCR) technique.

Results: (1) the expression of HIF-1alpha and sFlt-1 protein in preeclampsia group obviously increased. Strong (+++) positive expression was observed in 9 and 11 cases respectively, significantly higher than in control group (2 and 3 cases) (P < 0.05), however, VEGF expression obviously reduced in preeclampsia group (P < 0.01). (2) the level of HIF-1alpha and sFlt-1 mRNA in preeclamptic placenta was 0.604 +/- 0.013, 0.898 +/- 0.041, significantly higher than 0.208 +/- 0.007 and 0.559 +/- 0.244 in normal placenta (P < 0.05). Although the level of VEGF mRNA increased in preeclampsia placenta, it was not significantly different from that in normal placenta (P > 0.05). The ratio of VEGF mRNA/sFlt-1mRNA obviously reduced in preeclampsia group and was significantly lower than in control group (P < 0.05). (3) in preeclampsia group, HIF-1alpha mRNA expression was positively correlated with the expression of sFlt-1 mRNA (r = 0.577, P < 0.05), and negatively correlated with the ratio of VEGF mRNA/sFlt-1 mRNA (r = -0.376, P < 0.05).

Conclusion: Abnormal high HIF-1alpha expression in preeclampsia placenta indicates that HIF-1alpha might play an important role in the pathogenesis of preeclampsia, possibly through affecting the cytotrophoblastic invasion and placental vascular reconstruction via the modulation of VEGF and sFlt-1 gene transcription.