Fetal brain sparing in a mouse model of chronic maternal hypoxia

Hypoxic stress is a common occurrence during human pregnancy, yet little is known about its effects on the fetal brain. This study examined the fetal hemodynamic responses to chronic hypoxia in an experimental mouse model of chronic maternal hypoxia (11% O2 from E14.5 to E17.5). Using high-frequency...

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Bibliographic Details
Published in:Journal of cerebral blood flow and metabolism 2019-06, Vol.39 (6), p.1172-1184
Main Authors: Cahill, Lindsay S, Hoggarth, Johnathan, Lerch, Jason P, Seed, Mike, Macgowan, Christopher K, Sled, John G
Format: Article
Language:English
Subjects:
Animals
Blood Flow Velocity
Brain - diagnostic imaging
Brain - physiopathology
Cerebrovascular Circulation
Disease Models, Animal
Female
Fetal Hypoxia - physiopathology
Fetus - physiopathology
Hemodynamics
Magnetic Resonance Imaging
Mice
Original
Pregnancy
Ultrasonography - methods
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Summary:Hypoxic stress is a common occurrence during human pregnancy, yet little is known about its effects on the fetal brain. This study examined the fetal hemodynamic responses to chronic hypoxia in an experimental mouse model of chronic maternal hypoxia (11% O2 from E14.5 to E17.5). Using high-frequency Doppler ultrasound, we found fetal cerebral and ductus venosus blood flow were both elevated by 69% and pulmonary blood flow was decreased by 62% in the fetuses exposed to chronic hypoxia compared to controls. This demonstrates that brain sparing persists during chronic fetal hypoxia and is mediated by “streaming,” where highly oxygenated blood preferentially flows through the ductus venosus towards the cerebral circulation, bypassing the liver and the lungs. Consistent with these changes in blood flow, the fetal brain volume measured by MRI is preserved, while the liver and lung volumes decreased compared to controls. However, hypoxia exposed fetuses were rendered vulnerable to an acute hypoxic challenge (8% O2 for 3 min), demonstrating global blood flow decreases consistent with imminent fetal demise rather than elevated cerebral blood flow. Despite this vulnerability, there were no differences in adult brain morphology in the mice exposed to chronic maternal hypoxia compared to controls.
ISSN:0271-678X
1559-7016
DOI:10.1177/0271678X17750324