Background
During pregnancy, cells from the placenta (trophoblasts) are extruded into the maternal circulation and then lodge in the maternal lungs. In normal pregnancy the extruded trophoblasts are thought to die by programmed cell death. However, in preeclampsia, they are thought to die by a more necrotic mechanism and may trigger vascular dysfunction. Our aim was to determine whether administration of necrotic trophoblasts during pregnancy would induce hypertension in vivo.
Methods
Female Wistar rats were instrumented with a telemetry device for measurement of mean arterial pressure (MAP), and a vascular access port in the jugular vein for cell delivery. After recovery, the rats were mated and from day 6 of gestation were injected daily for the remaining two weeks of gestation with either vehicle or Jeg-3 (trophoblast) cells (5x106 cells/kg) rendered necrotic by freeze-thawing. Spectral analysis techniques were used to investigate the relative influence of the sympathetic and parasympathetic nervous systems during pregnancy in both groups of rats.
Results
MAP was not significantly different between the two groups during the first two weeks of gestation. During the third week the MAP of the control rats decreased however, the MAP of the rats injected with necrotic Jeg-3 cells did not and was significantly higher than control rats.
Conclusions
Our results suggest necrotic trophoblastic cells can adversely affect blood pressure, increasing it significantly above normal levels expected in late gestation. This provides preliminary evidence that necrotic trophoblasts may be one of the placental triggers of preeclampsia.
Disclosure
Sarah-Jane Guild is a part time employee of Telemetry Research Ltd who manufacture the telemetry devices used in this study.