Pregnancy enhances the effects of hypercholesterolemia on posterior cerebral arteries

Area of Science:

• Cardiovascular Physiology
• Neurovascular Function
• Reproductive Biology

Background:

• Preeclampsia is associated with hyperlipidemia, potentially impacting vascular health.
• Cerebral vasculature dysfunction can lead to neurological issues during pregnancy.

Purpose of the Study:

• To investigate the effects of excessive hyperlipidemia on cerebral artery function and inflammation during pregnancy.
• To compare responses in pregnant and nonpregnant rats under high-cholesterol conditions.

Main Methods:

• Rats (pregnant and nonpregnant) were fed a high-cholesterol or normal diet for 14 days.
• Posterior cerebral artery function was assessed, including responses to nitric oxide donors and myogenic tone.
• Messenger RNA (mRNA) expression of inducible nitric oxide synthase was quantified.

Main Results:

• High cholesterol increased posterior cerebral artery sensitivity to sodium nitroprusside in pregnant rats.
• Inducible nitric oxide synthase mRNA expression was significantly elevated (~12-fold) in late-pregnant rats on a high-cholesterol diet.
• Peroxynitrite-induced dilation was enhanced, and myogenic tone was reduced in cerebral arteries from hyperlipidemic pregnant rats.

Conclusions:

• Pathologically high cholesterol levels in pregnancy exacerbate inflammatory responses in cerebral arteries.
• Excessive cholesterol promotes peroxynitrite generation, potentially contributing to cerebrovascular dysfunction in preeclampsia.