Objective: Since placentae in trisomy 21 show trophoblastic hypoplasia and hypovascularity, we investigated amniotic fluid vascular endothelial growth factor (VEGF) and nitric oxide (NO) in normal pregnancy and pregnancy complicated by trisomy 21. Furthermore, we investigated a possible role of NO in neurodegeneration of the brain in Down's syndrome.
Methods: We retrospectively assessed NO and VEGF on mid-trimester amniotic fluid from 15 women who had fetal Down's syndrome, and compared the results with those of 15 controls matched for age and gestation.
Results: In pregnancies complicated by trisomy 21, NO levels were significantly higher than in healthy controls (p < 0.001), whereas VEGF levels were significantly lower than in healthy controls (p < 0.05).
Conclusions: Our results suggest that the high levels of NO and the low levels of VEGF observed in the amniotic fluid of fetuses with Down's syndrome may be a sign of an imbalance of placental vascularization and altered endothelial function. Overproduction of NO could contribute to pathological cell death in the central nervous system, a process that has been demonstrated in many neurodegenerative diseases.