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DOI: 10.1055/s-0028-1088670
Adenosine receptor A2A expression is higher in placentas of women with preeclampsia
Hypoxia is a potent stimulus for the release of adenosine and angiogenic factors in tissues. Women with preeclampsia show evidence of placental hypoxia and increased concentrations of adenosine in the circulation. It is suggested that activation of adenosine receptors is an adaptive response to reduce hypoxic injury in different tissues. Objective: We tested the hypotheses that the adenosine receptor subtype A2A is expressed in the placenta, expression is altered in preeclamptic pregnancies and under in vitro hypoxic conditions. Methods: Placentas were obtained from primiparous women with uncomplicated pregnancies or preeclampsia. Placental microvillous membranes (MVM) were prepared according to a standard protocol or villous explants were dissected and incubated for 24h at 2% oxygen or under standard conditions (20% oxygen). Western blotting was performed for detection of adenosine A2A receptor and HIF–1α. Data are presented as mean±SEM or fold changes compared to control values. Statistical analyzes were performed with Mann-Whitney or Wilcoxon-signed rank test. Probability values were considered significant at p<0.05. Results: Adenosine receptor subtype A2A is expressed in placental biopsies, villous explants and MVM. The expression was significantly higher in MVM from preeclamptic women (N=5, p=0.04) compared to uncomplicated pregnancies, respectively. In vitro hypoxia increased A2A-R and HIF–1α protein in villous explants (N=4, p=0.06, 0.03). Conclusions: Our results suggest a potential role for adenosine receptors in the pathophysiology of preeclampsia. Further studies will focus on the role of adenosine receptors in the regulation of placental function.
adenosine - adenosine receptor - hypoxia - placenta - preeclampsia