Submitted on September 24, 2008
Revised on January 26, 2009
Accepted on January 28, 2009
Impaired vascular function in mice with an active cytomegalovirus infection
Randi B Gombos1, Vanessa Wolan1, Kaitlin McDonald1, and Denise G Hemmings2*
1 University of Alberta
2 University of Alberta, Canada
* To whom correspondence should be addressed. E-mail: denise.hemmings{at}ualberta.ca.
Human cytomegalovirus (HCMV) is implicated in vascular complications through endothelial dysfunction. However, the effect of in vivo infections on vascular function in isolated arteries has not been examined. In pregnancy, systemic and uterine vascular adaptations accommodate increased blood volume through several mechanisms including decreased sensitivity to vasoconstrictors and increased production of endothelial-dependent vasodilators. We hypothesized that an active in vivo CMV infection would reduce vasodilation of isolated arteries to the endothelial-dependent vasodilator, methacholine and increase vasoconstriction to the 
1-adrenergic receptor agonist, phenylephrine, and that these CMV-induced changes would be accentuated in late pregnancy. A mouse CMV infection model was used to study vascular responses in isolated mesenteric and uterine arteries from non-pregnant and late pregnant mice. In the mouse, CMV is not transmitted to the fetus. Accordingly, there was no evidence of active infection in any fetus examined even though an active infection was found in salivary glands, uterine and mesenteric arteries and placentas. Contrary to our hypothesis, increased endothelial-dependent vasodilation was found in mesenteric arteries from infected compared to uninfected non-pregnant and pregnant mice These data implicate active CMV infections in hypotensive disorders. Similarly, increased vasodilation was found in uterine arteries from infected versus uninfected non-pregnant mice. However, this was completely reversed in infected compared to uninfected late pregnant mice where vasodilation in uterine arteries was significantly reduced. Uterine arteries from infected pregnant mice also showed increased vasoconstriction to phenylephrine. Maternal infection led to decreased placental weights but had no effect on fetal weights in late pregnancy. These novel data demonstrate abnormal systemic and uterine vascular responses during an active CMV infection in both non-pregnant and late pregnant mice. Importantly, despite reduced placental weights, fetal weights were maintained, suggesting effective intrauterine compensation in the mouse model.
