Compensatory placental development after treatment for congenital CMV infection

University Of California, San Francisco, San Francisco CA

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Abstract

Primary cytomegalovirus (CMV) infection affects 1-3% of pregnancies, causing intrauterine growth restriction (IUGR) and permanent birth defects in a quarter of congenitally infected babies. Birth defects from congenital CMV disease are as frequent as those from Down syndrome, fetal alcohol syndrome and neural tube defects. Symptomatic infants often die in the neonatal period, and most survivors have permanent debilitating sequelae, including mental retardation, vision loss and sensorineural deafness. This application builds on our knowledge of CMV infection in the pregnant uterus, patterns of infection in the developing placenta, and protection by maternal antibodies. Analysis of placentas from a clinical trial of hyperimmune globulin (HIG) for treatment of congenital CMV infection showed that untreated placentas had high levels of fibrosis, necrosis and syncytial knotting from sustained viral replication and chronic hypoxia. Remarkably, HIG-treated placentas generated many new villi and capillaries, indicating remodeling and compensatory adaptation. Early HIG treatment significantly reduced fetal infection. Newly acquired evidence, supported by statistical analysis of quantitative data, shows that chronic exposure to anti-angiogenic cellular factors can impair placental responses to hypoxia. These factors, concentrated in amniotic fluid and detected in maternal sera, hold promise as early biomarkers of congenital infection. In addition, chronic exposure to an immunosuppressive viral cytokine may affect cell migration/invasion and modulate cellular immune responses in the fetus. The long-term goal is to understand fundamental molecular mechanisms underlying viral dysregulation of placental development and paracrine factors in a hypoxic environment. The specific aims are as follows. Aim 1. Complete evaluation of viral damage and hypoxia associated with chorionic villus regeneration in placentas from untreated and HIG-treated congenital CMV infection. Study extracellular matrix deposition by placental cells that contributes to fibrosis. Aim 2. Quantify angiogenic factors and antagonists in maternal and fetal samples from congenital CMV infection. Correlate levels with fetal outcome to verify potential biomarkers of infection. Study effects of anti-angiogenic factors in specialized cells under hypoxic conditions. Aim. 3. Study mechanisms whereby cmvIL-10 and SOCS3 dysregulate chemokine signaling and downstream functions. Investigate paracrine effects of soluble CEACAM1 on cell migration. Hypoxia and IUGR in congenital CMV infection induce a subset of factors elevated in preeclampsia. Fundamental knowledge from our research could verify biomarkers of infection that correlate with fetal outcome. Translation of this research to diagnostic tests and therapeutic interventions to prevent disease could prove broadly beneficial to maternal and fetal health.