In the midst of an unprecedented Zika crisis in Brazil, there were a few flickers of hope: Some babies appeared to be normal at birth, free of devastating birth defects that affected other Brazilian children exposed to the virus in utero.
In the midst of an unprecedented Zika crisis in Brazil, there were a few flickers of hope: Some babies appeared to be normal at birth, free of devastating birth defects that affected other Brazilian children exposed to the virus in utero. But according to a study published online July 8, 2019, in Nature Medicine and an accompanying commentary co-written by a Children’s National clinician-researcher, the reality for Zika-exposed infants is much more complicated.
Study authors led by Karin Nielsen-Saines at David Geffen UCLA School of Medicine followed 216 infants in Rio de Janeiro who had been exposed to the Zika virus during pregnancy, performing neurodevelopmental testing when the babies ranged in age from 7 to 32 months. These infants’ mothers had had Zika-related symptoms themselves, including rash.
Although many children had normal assessments, 29% scored below average in at least one domain of neurological development, including cognitive performance, fine and gross motor skills and expressive language, Sarah B. Mulkey, M.D., Ph.D., and a colleague write in a companion commentary published online by Nature Medicine July 29, 2019.
The study authors found progressively higher risks for developmental, hearing and eye abnormality depending on how early the pregnancy was at the time the infants were exposed. Because Zika virus has an affinity for immature neurons, even babies who were not born with microcephaly remained at continued risk for suffering abnormalities.
Of note, 24 of 49 (49%) infants who had abnormalities at birth went on to have normal test results in the second or third year of life. By contrast, 17 of 68 infants (25%) who had normal assessments at birth had below-average developmental testing or had abnormalities in hearing or vision by age 32 months.
“This work follows babies who were born in 2015 and 2016. It’s heartening that some babies born with abnormalities tested in the normal range later in life, though it’s unclear whether any specific interventions help to deliver these positive findings,” says Dr. Mulkey, a fetal–neonatalneurologist in the Division of Fetal and Transitional Medicine at Children’s National in Washington, D.C. “And it’s quite sobering that babies who appeared normal at birth went on to develop abnormalities due to that early Zika exposure.”
It’s unclear how closely the findings apply to the vast majority of U.S. women whose Zika infections were asymptomatic.
“This study adds to the growing body of research that argues in favor of ongoing follow-up for Zika-exposed children, even if their neurologic exams were reassuring at birth,” Dr. Mulkey adds. “As Zika-exposed children approach school age, it’s critical to better characterize the potential implications for the education system and public health.”
In addition to Dr. Mulkey, the perspective’s senior author, William J. Muller, Northwestern University, was the commentary’s lead author.
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About three years ago, Zika virus emerged as a newly recognized congenital infection, and a growing body of research indicates the damage it causes differs from other infections that occur in utero.
Seventy-one of 110 Brazilian infants at the highest risk for experiencing problems due to exposure to the Zika virus in the womb experienced a wide spectrum of brain abnormalities, including calcifications and malformations in cortical development, according to a study published July 31, 2019 in JAMA Network Open.
The infants were born at the height of Brazil’s Zika epidemic, a few months after the nation declared a national public health emergency. Already, many of the infants had been classified as having the severe form of congenital Zika syndrome, and many had microcephaly, fetal brain disruption sequence, arthrogryposis and abnormal neurologic exams at birth.
These 110 infants “represented a group of ZIKV-exposed infants who would be expected to have a high burden of neuroimaging abnormalities, which is a difference from other reported cohorts,” Sarah B. Mulkey, M.D., Ph.D., writes in an invited commentary published in JAMA Network Open that accompanies the Rio de Janeiro study. “Fortunately, many ZIKV-exposed infants do not have abnormal brain findings or a clinical phenotype associated with congenital Zika syndrome,” adds Dr. Mulkey, a fetal–neonatalneurologist in the Division of Fetal and Transitional Medicine at Children’s National in Washington, D.C.
Indeed, a retrospective cohort of 82 women exposed to Zika during their pregnancies led by a research team at Children’s National found only three pregnancies were complicated by severe fetal brain abnormalities. Compared with the 65% abnormal computed tomography (CT) or magnetic resonance imaging (MRI) findings in the new Brazilian study, about 1 in 10 (10%) of babies born to women living in the continental U.S. with confirmed Zika infections during pregnancy had Zika-associated birth defects, according to the Centers for Disease Control and Prevention.
“There appears to be a spectrum of brain imaging abnormalities in ZIKV-exposed infants, including mild, nonspecific changes seen at cranial US [ultrasound], such as lenticulostriate vasculopathy and germinolytic cysts, to more significant brain abnormalities, such as subcortical calcifications, ventriculomegaly and, in its most severe form, thin cortical mantle and fetal brain disruption sequence,” Dr. Mulkey writes.
About three years ago, Zika virus emerged as a newly recognized congenital infection, and a growing body of research indicates the damage it causes differs from other infections that occur in utero. Unlike congenital cytomegalovirus infection, cerebral calcifications associated with Zika are typically subcortical, Dr. Mulkey indicates. What’s more, fetal brain disruption sequence seen in Zika-exposed infants is unusual for other infections that can cause microcephaly.
“Centered on the findings of Pool, et al, and others, early neuroimaging remains one of the most valuable investigations of the Zika-exposed infant,” Dr. Mulkey writes, including infants who are not diagnosed with congenital Zika syndrome. She recommends:
Cranial ultrasound as the first-line imaging option for infants, if available, combined with neurologic and ophthalmologic exams, and brainstem auditory evoked potentials
Zika-exposed infants with normal cranial ultrasounds do not need additional imaging unless they experience a developmental disturbance
Zika-exposed infants with abnormal cranial ultrasounds should undergo further neuroimaging with low-dose cranial CT or brain MRI.
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Research by an international team that includes Children’s National faculty, published online Jan. 25, 2019 in Human Molecular Genetics, suggests that genetic mutations that cause cleft lip and palate also may contribute to neural tube defects, such as spina bifida.
Oral clefts are some of the most common birth defects worldwide, affecting about one in every 700 births. In the U.S., more than 4,000 babies are born each year with cleft lip, with or without cleft palate.
This defect isn’t simply a cosmetic manner: Oral clefts can severely affect feeding, speech and hearing, and they cause about 3,300 deaths annually worldwide.
To better understand these conditions, researchers have isolated a number of genetic mutations that appear to play contributing roles. These include those in a gene known as Interferon Regulatory Factor 6. New research by an international team that includes Children’s National faculty, published online Jan. 25, 2019 in Human Molecular Genetics, suggests that these mutations also may contribute to neural tube defects such as spina bifida.
In the first weeks of fetal development, the neural plate curves, creating a neural tube that, once fused shut, becomes the fetal brain and fetal spinal cord. Neural tube defects, which can range from mild to severe, are characterized by incomplete development of the brain, spinal cord or meninges. These defects can potentially result in paralysis or even fetal or neonatal demise. According to the National Institutes of Health, spina bifida, which affects the spinal cord, is the most common neural tube defect in the U.S., affecting up to 2,000 infants each year.
“Despite its high frequency, spina bifida remains among the least understood structural birth defects,” says Brian C. Schutte, an associate professor of Microbiology and Molecular Genetics, Pediatrics and Human Development at Michigan State University and the study’s senior author. “There is strong evidence that genetic factors are a leading cause of such structural birth defects, but in most cases, the cause is unknown. Our team’s study is the first published research to demonstrate that DNA variants in the gene IRF6 can cause spina bifida,” Schutte says.
What’s more, the research team identified a mechanism to explain how altering IRF6 leads to neural tube defects. This mechanism links IRF6 function to two other genes – known as transcription Factor AP2A (TFAP2A) and Grainyhead Like 3 (GRHL3) – that are also known to be required for the development of the neural tube, lip and palate.
“We’re all on the hunt for the reasons when, how and why birth defects happen,” adds Youssef A. Kousa, MS, D.O., Ph.D., a clinical fellow in the Division of Child Neurology at Children’s National Health System and the study’s lead author. “Our main goal is prevention. This paper is a significant development because our team has identified a group of genes that can potentially contribute to very common types of birth defects: craniofacial as well as neural tube defects.”
The scientific odyssey is a wonderful example of serendipity. Kousa, then working in Schutte’s lab, was studying the effects of a new mutant experimental model strain on development of the palate. But one day, he walked into Schutte’s office holding a deformed preclinical embryo and said: “Brian, look at this!”
“Weird things happen in biology,” Schutte replied and counseled him to return if it happened again. Less than two weeks later, Kousa was back with several more of the deformed preclinical embryos, saying: “OK, Brian. It happened again.”
Within hours Kousa had unearthed recently published research that included an image of a similarly affected preclinical embryo. The pair then sketched out possible intersecting genetic pathways, as they brainstormed the myriad ways to end up with that specific phenotype. Initially, they tested their hypotheses in experimental models and eventually corroborated findings through human genetic studies.
The human studies could only be performed by collaborations. Schutte shared their initial observations with human genetics researchers scattered across the country. Those labs then generously agreed to test whether DNA variants in IRF6 were associated with neural tube defects in samples from patients that they had collected over decades of research.
The team found that Tfap2a, Irf6 and Grhl3 are components of a gene regulatory network required for neurulation, a folding process that results in the neural tube bending and then fusing to become the basis of the embryo’s nervous system, from brain to spinal cord.
“Since this network is also required for formation of the lip, palate, limbs and epidermis, which develop at different times and places during embryogenesis, we suggest that the Tfap2a–Irf6–Grhl3 network is a fundamental pathway for multiple morphogenetic processes,” the researchers write.
Interferon Regulatory Factor 6 functions best when there is neither too much expression nor too little. Overexpression of Irf6 suppresses Transcription Factor Activation Protein 2A and Grainyhead Like 3, causing exencephaly, a neural tube defect characterized by the brain being located outside of the skull. Counterintuitively, experimental models that had too little Irf6 also ended up with reduced levels of Tfap2a and Grhl3 that led to a structural birth defect, but at the opposite end of the neural tube.
To test whether the experimental model findings held true in humans, they sequenced samples from people who had spina bifida and anencephaly – the rare birth defect that Kousa spotted in the experimental models – and found IRF6 function was conserved in people. Because of the genetic complexity of these birth defects, and the challenges inherent in collecting samples from cases of severe birth defects, many research teams were invited to participate in the study.
As testament to their collegiality, researchers from Stanford University, University of Texas at Austin, University of Iowa, University of Texas at Houston and Duke University agreed to share precious samples from the California Birth Defects Monitoring Program, from the Hereditary Basis of Neural Tube Defects study and from their own institutional sample collections.
“As we get better at personalized medicine, we could use this information to one day help to counsel families about their own risk and protective factors,” Kousa adds. “If we can identify the genetic pathway, we might also be able to modify it to prevent a birth defect. For example, prenatal supplementation with folic acid has led to a decrease in babies born with neural tube defects, but not all neural tube defects are sensitive to folic acid. This knowledge will help us develop individual-based interventions.”
Financial support for the research covered in this post was provided by the National Institutes of Health under grants DE13513, F31DE022696, DE025060, P01HD067244 and GM072859; startup funding from Michigan State University and the UT-Health School of Dentistry in Houston; and the Centers for Disease Control and Prevention under award number 5U01DD001033.
In addition to Kousa and Schutte, study co-authors include Huiping Zhu, Yunping Lei and Richard H. Finnell, University of Texas at Austin; Walid D. Fakhouri, University of Texas Health Science Center at Houston; Akira Kinoshita, Nagasaki University; Raeuf R. Roushangar, Nicole K. Patel, Tamer Mansour, Arianna L. Smith, and Dhruv B. Sharma, Michigan State University; A.J. Agopian and Laura E. Mitchell, University of Texas School of Public Health; Wei Yang and Gary M. Shaw, Stanford University School of Medicine; Elizabeth J. Leslie, Emory University; Xiao Li, Tamara D. Busch, Alexander G. Bassuk and Brad A. Amendt, University of Iowa; Edward B. Li and Eric C. Liao, Massachusetts General Hospital; Trevor J. Williams, University of Colorado Denver at Anschutz Medical Campus; Yang Chai, University of Southern California; and Simon Gregory and Allison Ashley-Koch, Duke University Medical Center.
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“A combination of prenatal MRI and US was able to detect Zika-related brain abnormalities during pregnancy, giving families timely information to prepare for the potential complex care needs of these infants,” says Sarah B. Mulkey, M.D., Ph.D.
Worldwide, thousands of babies have been born to mothers who were infected during pregnancy with Zika, a virus associated with neurological deficits, impaired vision and neurodevelopmental disabilities, among other birth defects. These birth defects are sometimes severe, causing lifelong disability. But they’re also relatively rare compared with the overall rates of infection.
Predicting how many Zika-exposed babies would experience neurological birth defects has been challenging.
However, an international study led by Children’s faculty suggests that ultrasound (US) imaging performed during pregnancy and after childbirth revealed most Zika-related brain abnormalities experienced by infants exposed to the Zika virus during pregnancy, according to a prospective cohort study published online Nov. 26, 2018, in JAMA Pediatrics. Some Zika-exposed infants whose imaging had been normal during pregnancy had mild brain abnormalities detected by US and magnetic resonance imaging (MRI) after they were born.
“A combination of prenatal MRI and US was able to detect Zika-related brain abnormalities during pregnancy, giving families timely information to prepare for the potential complex care needs of these infants,” says Sarah B. Mulkey, M.D., Ph.D., a fetal-neonatal neurologist at Children’s National Health System and the study’s lead author. “In our study, we detected mild brain abnormalities on postnatal neuroimaging for babies whose imaging was normal during pregnancy. Therefore, it is important for clinicians to continue to monitor brain development for Zika-exposed infants after birth.”
As of Nov. 20 2018, nearly 2,500 pregnant women in the U.S. had laboratory confirmed Zika infection, and about 2,400 of them had given birth, according to the Centers for Disease Control and Prevention (CDC). While more than 100 U.S. infants were born with Zika-associated birth defects, the vast majority of Zika-exposed U.S. infants were apparently normal at birth. The sequential neuroimaging study Dr. Mulkey leads seeks to determine the spectrum of brain findings in infants exposed to Zika in the womb using both US and MRI before and after birth.
The international research team enrolled 82 women in the study from June 15, 2016, through June 27, 2017. All of the women had been exposed to Zika during pregnancy; all but one experienced clinical symptoms by a mean gestational age of 8.2 weeks. Eighty of those women lived in or near Barranquilla, Colombia, and were exposed to Zika there. Two U.S. study participants were exposed to the primarily mosquito-borne illness during travel to Zika hot zones.
All women received fetal MRIs and US during the second and/or third trimester of pregnancy. After their infants were born, the children received brain MRI and cranial US. Blood samples from both mothers and babies were tested for Zika using polymerase chain reaction and serology.
Fetal MRI was able to discern Zika-related brain damage as early as 18 weeks gestation and picked up significant fetal brain abnormalities not fully appreciated in US imaging. In one case, the US remained normal while fetal MRI alone detected brain abnormalities. Three fetuses (4 percent) had severe fetal brain abnormalities consistent with Zika infection, including:
Two cases of heterotopias and malformations in cortical development, and
Seventy-five infants were born at term. One pregnancy was terminated at 23 weeks gestation due to the gravity of the fetal brain abnormalities. One fetus with normal imaging died during pregnancy. One newborn who was born with significant fetal brain abnormalities died at age 3 days.
Cranial US and brain MRI was performed on the majority of infants whose prenatal imaging had been normal. Seven of 53 (13 percent) Zika-exposed infants had mild brain abnormalities detected by MRI after birth. In contrast, postnatal cranial US was better at detecting changes of lenticulostriate vasculopathy, cysts within the brain’s choroid plexus (cells that produce cerebrospinal fluid), germinolytic/subependymal cysts and/or calcifications, which were seen in 21 of 57 (37 percent) infants.
“Sequential neuroimaging revealed that the majority of Zika-exposed fetuses had normal brain development. Tragically, in a small number of pregnancies, Zika-related brain abnormalities were quite severe,” Dr. Mulkey adds. “Our data support the CDC’s recommendation that cranial US be performed after Zika-exposed babies are born. In addition, there is clearly a need to follow these babies over time to gauge whether the brain anomalies we see in imaging affects language, motor and social skills.”
In addition to Dr. Mulkey, study co-authors include Dorothy I. Bulas, M.D., Gilbert Vezina, M.D., Margarita Arroyave-Wessel, MPH, Stephanie Russo, B.S, Youssef A. Kousa, D.O, Ph.D., Roberta L. DeBiasi, M.D., MS, Senior Author Adré J. du Plessis, M.B.Ch.B., MPH, all of Children’s National; Christopher Swisher, BS, Georgetown University and Caitlin Cristante, BS, Loyola University, both of whose contributions included research performed at Children’s National; Yamil Fourzali, M.D., Armando Morales, M.D., both of Sabbag Radiologos; Liliana Encinales, M.D., Allied Research Society; Nelly Pacheco, Bacteriologa, Bio-Nep; Robert S. Lanciotti, Ph.D., Arbovirus Diseases Branch, Centers for Disease Control and Prevention; and Carlos Cure, M.D., BIOMELAB.
Research reported in this news release was supported by the IKARIA fund.
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During the last few weeks of pregnancy, certain regions of the fetal brain experience exponential growth but also are more vulnerable to injury during that high-growth period.
Yao Wu, Ph.D., a research postdoctoral fellow in the Developing Brain Research Laboratory at Children’s National Health System, has received a Thrasher Research Fund early career award to expand knowledge about regions of the fetal brain that are vulnerable to injury from congenital heart disease (CHD) during pregnancy.
CHD, the most common birth defect, can have lasting effects, including overall health issues; difficulty achieving milestones such as crawling, walking or running; and missed days at daycare or school, according to the Centers for Disease Control and Prevention. Brain injury is a major complication for infants born with CHD. Catherine Limperopoulos, Ph.D., director of Children’s brain imaging lab, was the first to provide in vivo evidence that fetal brain growth and metabolism in the third trimester of pregnancy is impaired within the womb.
“It remains unclear which specific regions of the fetal brain are more vulnerable to these insults in utero,” Limperopoulos says. “We first need to identify early brain abnormalities attributed to CHD and understand their impact on infants’ later behavioral and cognitive development in order to better counsel parents and effectively intervene during the prenatal period to safeguard brain health.”
During the last few weeks of pregnancy, certain regions of the fetal brain experience exponential growth but also are more vulnerable to injury during that high-growth period. The grant, $26,749 over two years, will underwrite “Brain Development in Fetuses With Congenital Heart Disease,” research that enables Wu to utilize quantitative, non-invasive magnetic resonance imaging (MRI) to compare fetal brain development in pregnancies complicated by CHD with brain development in healthy fetuses of the same gestational age.Wu will leverage quantitative, in vivo 3-D volumetric MRI to compare overall fetal and neonatal brain growth as well as growth in key regions including cortical grey matter, white matter, deep grey matter, lateral ventricles, external cerebrospinal fluid, cerebellum, brain stem, amygdala and the hippocampus.
The research is an offshoot of a prospective study funded by the National Institutes of Health that uses advanced imaging techniques to record brain growth in 50 fetuses in pregnancies complicated by CHD who need open heart surgery and 50 healthy fetuses. MRI studies are conducted during the second trimester (24 to 28 weeks gestational age), third trimester (33 to 37 weeks gestational age) and shortly after birth but before surgery. In addition, fetal and neonatal MRI measurements will be correlated with validated scales that measure infants’ and toddlers’ overall development, behavior and social/emotional maturity.
“I am humbled to be selected for this prestigious award,” Wu says. “The findings from our ongoing work could be instrumental in identifying strategies for clinicians and care teams managing high-risk pregnancies to optimize fetal brain development and infants’ overall quality of life.”
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Researchers have known for decades that folate, a vitamin enriched in dark, leafy vegetables; fruit; nuts; and other food sources, plays a key role in preventing neural tube defects.
Every year, about 3,000 pregnancies in the U.S. are affected by neural tube defects (NTDs) – birth defects of the brain, spine and spinal cord. These include anencephaly, in which a major part of the brain, skull and scalp is missing; and spina bifida, in which the backbone and membranes around the spinal cord don’t close properly during fetal development. These structural birth defects can have devastating effects: In the best cases, they might lead to mild but lifelong disability; in the worst cases, babies don’t survive.
Researchers have known for decades that folate, a vitamin enriched in dark, leafy vegetables; fruit; nuts; and other food sources, plays a key role in preventing NTDs. To help get more folate into pregnant women’s diets, wheat flour in the U.S. and many other countries is often fortified with folic acid, a synthetic version of this vitamin, as part of an intervention credited with significantly reducing the incidence of NTDs.
But folic acid supplementation isn’t enough, says Irene E. Zohn, Ph.D., a principal investigator at the Center for Neuroscience Research at Children’s National Health System who studies how genes and the environment interact during development. A significant number of NTDs still occur, suggesting that other approaches – potentially, other nutrients in the maternal diet – might provide further protection.
That’s why Zohn and colleagues decided to investigate iron. Iron deficiency is one of the most common micronutrient deficiencies in women of childbearing age, Zohn explains. Additionally, iron and folate deficiencies often overlap and signal overall poor maternal diets.
The idea that iron deficiency might play a role in NTDs came from studies by Zohn and colleagues of the flatiron mutant line of experimental models. This experimental model line has a mutation in a gene that transports iron across cell membranes, including the cells that supply embryos with this critical micronutrient.
To determine if NTDs develop in these mutant experimental models because of reduced iron transport, the researchers devised a simple experiment: They took female adult experimental models with the mutation and separated them into four groups. For several weeks, one group ate a diet that was high in folic acid. Another group ate a diet high in iron. The third group ate a diet high in both folic acid and iron. The fourth group ate standard chow. All of these experimental models then became pregnant with embryos that harbored the flatiron mutation, and the researchers assessed the offspring for the presence of NTDs.
“We were hoping that iron supplements would be the next folic acid, but it did not turn out that way,” says Irene E. Zohn, Ph.D. “Even though our results demonstrate that iron is important for proper neural tube development, giving extra iron definitely has its downsides.”
As they reported in Birth Defects Research, the dietary interventions successfully increased iron stores: Experimental model mothers whose diets were supplemented with iron, folic acid or both had increased concentrations of these micronutrients in their blood.
The dietary interventions also affected their offspring. While about 80 percent of flatiron mutant embryos fed a standard diet during pregnancy had NTDs, feeding a diet high in iron prevented NTDs in half of the offspring. This lower rate was similar in the offspring of mothers fed a diet high in both folic acid and iron, but not for those whose mothers ate just a diet high in folic acid. Those embryos had NTD rates as high as those who ate just the standard chow, suggesting that low iron was the cause of the high rates, not low folic acid.
Together, Zohn says, these experiments show that iron plays an important role in the development of the neural tube and that deficits in iron might cause some cases of NTDs. However, she notes, reducing NTDs isn’t nearly as simple as supplementing pregnant women’s diets with iron. In the same study, the researchers found that when they gave normal experimental models that didn’t have the flatiron mutation concentrated iron supplements – amounts akin to what doctors might prescribe for human patients with very severe iron-deficiency anemia – folate stores dropped.
That’s because these two micronutrients interact in the body with similar sites for absorption and storage in the intestines and liver, Zohn explains. At either the intestines or liver or at both locations, an iron overload might interfere with the body’s ability to absorb or use folate.
At this point, she says, giving high doses of iron routinely during pregnancy doesn’t look like a feasible way to prevent NTDs.
“We were hoping that iron supplements would be the next folic acid, but it did not turn out that way,” Zohn says. “Even though our results demonstrate that iron is important for proper neural tube development, giving extra iron definitely has its downsides.”
Zohn’s team plans to continue to investigate the role of iron, as well as the role of other micronutrients that might influence neural tube development.
Zohn’s coauthors include Bethany A. Stokes, The George Washington University, and Julia A. Sabatino, Children’s National.
Research reported in this story was supported by a grant from the Board of Visitors, Eunice Kennedy Shriver National Institute of Child Health & Human Development under award number R21-HD076202, the National Center for Research Resources under award number UL1RR031988, Children’s Research Institute and the National Institutes of Health under grant P30HD040677.
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Roberta DeBiasi, M.D., M.S., outlined lessons learned during a pediatric virology workshop at IDWeek2017, one of three such Zika presentations led by Children’s National research-clinicians during this year’s meeting of pediatric infectious disease specialists.
The Congenital Zika Virus Program at Children’s National Health System provides a range of advanced testing and services for exposed and infected fetuses and newborns. Data that the program has gathered in evaluating and managing Zika-affected pregnancies and births may offer instructive insights to other centers developing similar programs.
The program evaluated 36 pregnant women and their fetuses from January 2016 through May 2017. Another 14 women and their infants were referred to the Zika program for postnatal consultations during that time.
“As the days grow shorter and temperatures drop, we continue to receive referrals to our Zika program, and this is a testament to the critical need it fulfills in the greater metropolitan D.C. region,” says Roberta L. DeBiasi, M.D., M.S., chief of the Division of Pediatric Infectious Diseases and co-leader of the program. “Our multidisciplinary team now has consulted on 90 dyads (mothers and their Zika-affected fetuses/infants). The lessons we learned about when and how these women were infected and how their offspring were affected by Zika may be instructive to institutions considering launching their own programs.”
Dr. DeBiasi outlined lessons learned during a pediatric virology workshop at IDWeek2017, one of three such Zika presentations led by Children’s National research-clinicians during this year’s meeting of pediatric infectious disease specialists.
“The Zika virus continues to circulate in dozens of nations, from Angola to the U.S. Virgin Islands. Clinicians considering a strategic approach to managing pregnancies complicated by Zika may consider enlisting an array of specialists to attend to infants’ complex care needs, including experts in fetal imaging, pediatric infectious disease, physical therapists, audiologists, ophthalmologists and radiologists skilled at reading serial magnetic resonance images as well as ultrasounds,” Dr. DeBiasi says. “At Children’s we have a devoted Zika hotline to triage patient and family concerns. We provide detailed instructions for referring institutions explaining protocols before and after childbirth, and we provide continuing education for health care professionals.”
Of the 36 pregnant women possibly exposed to Zika during pregnancy seen in the program’s first year, 32 lived in the United States and traveled to countries where Zika virus was circulating. Two women had partners who traveled to Zika hot zones. And two moved to the Washington region from places where Zika is endemic. Including the postnatal cases, 89 percent of patients had been bitten by Zika-tainted mosquitoes, while 48 percent of women could have been exposed to Zika via sex with an infected partner.
Twenty percent of the women were exposed before conception; 46 percent were exposed to Zika in the first trimester of pregnancy; 26 percent were exposed in the second trimester; and 8 percent were exposed in the final trimester. In only six of 50 cases (12 percent) did the Zika-infected individual experience symptoms.
Zika infection can be confirmed by detecting viral fragments but only if the test occurs shortly after infection. Twenty-four of the 50 women (nearly 50 percent) arrived for a Zika consultation outside that 12-week testing window. Eleven women (22 percent) had confirmed Zika infection and another 28 percent tested positive for the broader family of flavivirus infections that includes Zika. Another detection method picks up antibodies that the body produces to neutralize Zika virus. For seven women (14 percent), Zika infection was ruled out by either testing method.
“Tragically, four fetuses had severe Zika-related birth defects,” Dr. DeBiasi says. “Due to the gravity of those abnormalities, two pregnancies were not carried to term. The third pregnancy was carried to term, but the infant died immediately after birth. The fourth pregnancy was carried to term, but that infant survived less than one year.”
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An international study that includes Sarah B. Mulkey, M.D., Ph.D., aims to answer one of the most vexing questions about Zika: If babies’ brains appear “normal” at birth, have they survived Zika exposure in the womb with few neurological repercussions? Dr. Mulkey presented preliminary findings at PAS2017.
It has been well established by researchers, including scientists at Children’s National Health System, that the Zika virus is responsible for a slew of birth defects – such as microcephaly, other brain malformations and retinal damage – in babies of infected mothers. But how the virus causes these often devastating effects, and who exactly is affected, has not been explained fully.
Also unknown is whether exposed babies that appear normal at birth are truly unaffected by the virus or have hidden problems that might surface later. The majority of babies born to Zika-infected mothers in the United States appear to have no evidence of Zika-caused birth defects, but that’s no guarantee that the virus has not caused lingering damage.
Recently, Sarah B. Mulkey, M.D., Ph.D., made a trip to Colombia, where Children’s National researchers are collaborating on a clinical study. There, she tested Zika-affected babies’ motor skills as they sat, stood and lay facing upward and downward. The international study aims to answer one of the most vexing questions about Zika: If babies’ brains appear “normal” at birth, have they survived Zika exposure in the womb with few neurological repercussions?
“We don’t know the long-term neurological consequences of having Zika if your brain looks normal,” says Dr. Mulkey, a fetal-neonatal neurologist who is a member of Children’s Congenital Zika Virus Program. “That is what’s so scary, the uncertainty about long-term outcomes.”
According to the Centers for Disease Control and Prevention (CDC), one in 10 pregnancies across the United States with laboratory-confirmed Zika virus infection results in birth defects in the fetus or infant. For the lion’s share of Zika-affected pregnancies, then, babies’ long-term prospects remain a mystery.
“This is a huge number of children to be impacted and the impact, as we understand, has the potential to be pretty significant,” Dr. Mulkey adds.
Dr. Mulkey, the lead author, presented the research group’s preliminary findings during the 2017 annual meeting of the Pediatric Academic Societies (PAS). The presentation was one of several that focused on the Zika virus. Roberta L. DeBiasi, M.D., M.S., chief of the Division of Pediatric Infectious Diseases at Children’s National, organized two invited symposia devoted to the topic of Zika: Clinical perspectives and knowledge gaps; and the science of Zika, including experimental models of disease and vaccines. Dr. DeBiasi’s presentation included an overview of the 68 Zika-exposed or infected women and infants seen thus far by Children’s multidisciplinary Congenital Zika Virus Program.
“As the world’s largest pediatric research meeting, PAS2017 is an ideal setting for panelists to provide comprehensive epidemiologic and clinical updates about the emergence of Congenital Zika Syndrome and to review the pathogenesis of infection as it relates to the fetal brain,” Dr. DeBiasi says. “With temperatures already rising to levels that support spread of the Aedes mosquito, it is imperative for pediatricians around the world to share the latest research findings to identify the most effective interventions.”
As one example, Dr. Mulkey’s research sought to evaluate the utility of using magnetic resonance imaging (MRI) to evaluate fetal brain abnormalities in 48 babies whose mothers had confirmed Zika infection during pregnancy. Forty-six of the women/infant pairs enrolled in the prospective study are Colombian, and two are Washington, D.C. women who were exposed during travel to a Zika hot zone.
The women were infected with Zika during all three trimesters and experienced symptoms at a mean gestational age of 8.4 weeks. The first fetal MRIs were performed as early as 18 weeks’ gestation. Depending upon the gestational age when they were enrolled in the study, the participants had at least one fetal MRI as well as serial ultrasounds. Thirty-six fetuses had a second fetal MRI at about 31.1 gestational weeks. An experienced pediatric neuroradiologist evaluated the images.
Among the 48 study participants, 45 had “normal” fetal MRIs.
Three fetuses exposed to Zika in the first or second trimester had abnormal fetal MRIs:
One had heterotopia and an early, abnormal fold on the surface of the brain, indications that neurons did not migrate to their anticipated destination during brain development. This pregnancy was terminated at 23.9 gestational weeks.
One had parietal encephalocele, a rare birth defect that results in a sac-like protrusion of the brain through an opening in the skull. According to the CDC, this defect affects one in 12,200 births, or 340 babies, per year. It is not known if this rare finding is related to Zika infection.
One had a thin corpus callosum, dysplastic brainstem, heterotopias, significant ventriculomegaly and generalized cerebral/cerebellar atrophy.
“Fetal brain MRI detected early structural brain changes in fetuses exposed to the Zika virus in the first and second trimester,” Dr. Mulkey says. “The vast majority of fetuses exposed to Zika in our study had normal fetal MRI, however. Our ongoing study, underwritten by the Thrasher Research Fund, will evaluate their long-term neurodevelopment.”
Adré J. du Plessis, MB.Ch.B., M.P.H., director of the Fetal Medicine Institute and senior author of the paper, notes that this group “is a very important cohort to follow as long as Dr. Mulkey’s funding permits. We know that microcephaly is among the more devastating side effects caused by Zika exposure in utero. Unanswered questions remain about Zika’s impact on hearing, vision and cognition for a larger group of infants. Definitive answers only will come with long-term follow-up.”
Many of the Colombian families live in Sabanalarga, a relatively rural, impoverished area with frequent rain, leaving pockets of fresh water puddles that the mosquito that spreads Zika prefers, Dr. Mulkey adds. Families rode buses for hours for access to fetal MRI technology, which is not common in Colombia.
“The mothers are worried about their babies. They want to know if their babies are doing OK,” she says.
https://innovationdistrict.childrensnational.org/wp-content/uploads/2017/05/Sarah-Mulkey-Columbia-Zika-Study.jpg300400Innovation Districthttps://innovationdistrict.childrensnational.org/wp-content/uploads/2023/12/innovationdistrict_logo-1-1030x165.pngInnovation District2017-05-22 15:19:372019-09-16 09:57:09Damage may lurk in “normal” Zika-exposed brains
A multidisciplinary team at Children’s National has consulted on 66 Zika-affected pregnancies and births since May 2016.
The first pregnant patient with worries about a possible Zika virus infection arrived at the Children’s National Health System Fetal Medicine Institute on Jan. 26, 2016, shortly after returning from international travel.
Sixteen months ago, the world was just beginning to learn how devastating the mosquito-borne illness could be to fetuses developing in utero. As the epidemic spread, a growing number of sun-splashed regions that harbor mosquitoes that efficiently spread the virus experienced a ballooning number of Zika-affected pregnancies and began to record sobering birth defects.
The Washington, D.C. patient’s concerns were well-founded. Exposure to Zika virus early in her pregnancy led to significant fetal brain abnormalities, and Zika virus lingered in the woman’s bloodstream months after the initial exposure — longer than the Centers for Disease Control and Prevention (CDC) then thought was possible.
In the intervening months, a multidisciplinary team at Children National has consulted on 66 pregnancies and infants with confirmed or suspected Zika exposure. Thirty-five of the Zika-related evaluations were prenatal, and 31 postnatal evaluations assessed the impact of in utero Zika exposure after the babies were born.
The continuum of Zika-related injuries includes tragedies, such as a 28-year-old pregnant woman who was referred to Children’s National after imaging hinted at microcephaly. Follow-up with sharper magnetic resonance imaging (MRI) identified severe diffuse thinning of the cerebral cortical mantle, evidence of parenchymal cysts in the white matter and multiple contractures of upper and lower extremities with muscular atrophy.
According to a registry of Zika-affected pregnancies maintained by the CDC, one in 10 pregnancies across the United States with laboratory-confirmed Zika virus infection has resulted in birth defects in the fetus or infant.
“More surprising than that percentage is the fact that just 25 percent of infants underwent neuroimaging after birth – despite the CDC’s recommendation that all Zika-exposed infants undergo postnatal imaging,” says Roberta L. DeBiasi, M.D., M.S., chief of the Division of Pediatric Infectious Diseases and co-director of the Congenital Zika Virus Program at Children’s National. “Clinicians should follow the CDC’s guidance to the letter, asking women about possible exposure to Zika and providing multidisciplinary care to babies after birth. Imaging is an essential tool to accurately monitor the growing baby’s brain development.”
Adré du Plessis, M.B.Ch.B., M.P.H., director of the Fetal Medicine Institute and Congenital Zika Virus Program co-leader, explains the challenges: ”When it comes to understanding the long-term consequences for fetuses exposed to the Zika virus, we are still on the steepest part of the learning curve. Identifying those children at risk for adverse outcomes will require a sustained and concerted multidisciplinary effort from conception well beyond childhood.”
In addition to counseling families in the greater Washington, D.C. region, the Children’s research team is collaborating with international colleagues to conduct a clinical trial that has been recruiting Zika-infected women and their babies in Colombia. Pediatric Resident Youssef A. Kousa, D.O., Ph.D., M.S., and Neurologist Sarah B. Mulkey, M.D., Ph.D., will present preliminary findings during Research and Education Week 2017.
In Colombia as well as the District of Columbia, a growing challenge continues to be assessing Zika’s more subtle effects on pregnancies, developing fetuses and infants, says Radiologist Dorothy Bulas, M.D., another member of Children’s multidisciplinary Congenital Zika Virus Program.
The most severe cases from Brazil were characterized by interrupted fetal brain development, smaller-than-normal infant head circumference, brain calcifications, enlarged ventricles, seizures and limbs folded at odd angles. In the United States and many other Zika-affected regions, Zika-affected cases with such severe birth defects are outnumbered by infants who were exposed to Zika in utero but have imaging that appears normal.
In a darkened room, Dr. Bulas pores over magnified images of the brains of Zika-infected babies, looking for subtle differences in structure that may portend future problems.
“There are some questions we have answered in the past year, but a number of questions remain unanswered,” Dr. Bulas says. “For neonates, that whole area needs assessment. As the fetal brain is developing, the Zika virus seems to affect the progenitor cells. They’re getting hit quite early on. While we may not detect brain damage during the prenatal period, it may appear in postnatal images. And mild side effects that may not be as obvious early on still have the potential to be devastating.”
https://innovationdistrict.childrensnational.org/wp-content/uploads/2016/08/DeBiasi-and-du-Plessis.jpg300400Innovation Districthttps://innovationdistrict.childrensnational.org/wp-content/uploads/2023/12/innovationdistrict_logo-1-1030x165.pngInnovation District2017-04-21 11:07:442019-03-11 10:00:24Zika virus, one year later
