Comparison of placental endothelin-1 (ET-1) expression under hypoxic condition between normal versus preeclamptic pregnancy

Park, Yong Won; Kwon, Ja Young; Kim, Young Han; Kim, Yuri; Lim, Jae Hak; Kang, Muong Hwa

Abstract

OBJECTIVE
To evaluate endothelin-1 (ET-1) expression in the villous explants from normal and preeclamptic (PE) placentae under hypoxic condition.
METHODS
Villous explants from normal (n=5) and PE (n=4) placentae were obtained. To obtain hypoxic culture condition, villous explants were cultured in hypoxic chamber or treated with deferoxamine (DFO). ET-1 mRNA expressions in villous explants were evaluated by RT-PCR following 0, 24, and 48 h of culture in hypoxic chamber, and 0, 2, 4, 6 h following DFO treatment. ET-1 protein levels in media were measured by enzyme immunoassay.
RESULTS
After 24 and 48 hours of incubation of villous explants from normal and PE placentae in hypoxic chamber, ET-1 mRNA and protein levels were increased in both groups, however, ET-1 production seemed to be more exaggerated in the villous explants from PE placentae. During 6 h of DFO exposure, ET-1 mRNA level was increased in the villous explants from PE placenta comparing to those from normal placentae (p<0.05). Interestingly, the increase of ET-1 mRNA expression in the villous explants from PE placentae was more exaggerated than those from normal placentae. Concordantly, increments of protein level between 0 to 2 h and 2 to 4 h were significantly higher in villous explants from PE placentae (p<0.05).
CONCLUSION
ET-1 mRNA and protein were increased in villous explants from PE placentae compared to those from normal placentae under hypoxic condition. Furthermore, villous explants from PE placentae showed upregulated ET-1 expression upon hypoxic stimulation. This enhanced sensitivity to hypoxia may contribute to ET-1 overexpression in PE placenta in vivo and it needs further investigation for clarification.