neurodevelopment Archives

School entry neurodevelopmental outcomes of Zika-exposed Colombian children

February 26, 2024

The Children’s National Hospital Zika Research Team and collaborators from Biomelab, in Barranquilla, Colombia take a picture after a study visit in Sabanalarga, Colombia following the neurodevelopmental outcomes of children who had in utero exposure to Zika virus. Pictured from Children’s National Hospital: Dr. Sarah Mulkey, Regan Andringa-Seed, Margarita Arroyave-Wessel, and Dr. Madison Berl.

The long-term neurodevelopmental effects of antenatal Zika virus (ZIKV) exposure in children without congenital Zika syndrome (CZS) remain unclear, as few children have been followed to the age of starting primary school.

In a new study published in Pathogens, researchers found children with in utero ZIKV exposure appear to have an overall positive developmental trajectory at 4 to 5 years of age but may experience risks to neurodevelopment in areas of emotional regulation and adaptive mobility.

The hold up in the field

Children who were born during the ZIKV epidemic and who had in utero exposure to ZIKV are only now at the age to start school. Child neurodevelopmental outcome data has not been reported at the age of school entry for children with antenatal ZIKV exposure who do not have the severe birth defects of CZS.

“As these children approach the early school-age years, we aim to examine whether there are neurodevelopmental differences in executive function, motor ability, language development or scholastic skills as compared to a group of unexposed control participants from the same communities in Colombia,” says Sarah Mulkey, M.D., Ph.D., prenatal-neonatal neurologist in The Zickler Family Prenatal Pediatrics Institute at Children’s National Hospital and lead author of the study.

Moving the field forward

Building on previous findings, this study presents the longitudinal outcomes of a well-characterized Colombian cohort of ZIKV-exposed children without CZS at ages 4 to 5 years. These children have been seen for neurodevelopmental follow-up as infants and toddlers at approximately 6 months, 18 months and 3 years of age as part of an international collaboration between researchers in Barranquilla, Colombia and at Children’s National beginning in 2016. The objective of this study was to assess the multi-domain neurodevelopmental outcomes in 4 to 5-year-old children with antenatal ZIKV exposure without CZS compared to unexposed controls in Colombia.

Why we’re excited

Many of the children who had antenatal ZIKV exposure are making good progress in multiple areas of their neurodevelopment. However, the researchers found that children with antenatal ZIKV exposure have differences in areas of emotional regulation, executive function, mood and behavior which may relate to virus exposure during their early brain development.

“These areas of brain function are important for future academic achievement, employment, mental health and social relationships,” says Dr. Mulkey. “So, it will be important to continue to follow these children at older ages when they start school.”

Children’s National leads the way

Children’s National is a leader in conducting outcome studies of children born following antenatal ZIKV exposure. This study follows children in Colombia who are now 5 years old who were first studied while they were in the womb. These children have contributed unique longitudinal understanding to early child neurodevelopment following in utero exposure to ZIKV.

Dr. Mulkey is committed to studying the long-term neurodevelopmental impacts that viruses like Zika and SARS-CoV-2 have on infants born to mothers who were infected during pregnancy through research with the Congenital Infection Program at Children’s National and in collaboration with colleagues in Colombia.

Additional Children’s National authors include Meagan Williams M.S.P.H., C.C.R.C., senior research coordinator; Regan Andringa-Seed, clinical research coordinator, Margarita Arroyave-Wessel, clinical research coordinator; L. Gilbert Vezina, M.D., director, Neuroradiology Program; Dorothy Bulas, M.D., chief, Diagnostic Imaging and Radiology; Robert Podolsky, biostatistician.

Researchers showing paintings of zika virus

Dr. Sarah Mulkey and Children’s National clinical research coordinators in the Prenatal Pediatrics Institute and the Division of Pediatric Infectious Diseases display their paintings of the Zika virus. Pictured from left to right: Manuela Iglesias, Elizabeth Corn, Dr. Sarah Mulkey, Emily Ansusinha and Meagan Williams.

Early SARS-CoV-2 exposure may impact infant development

November 30, 2022

The study found that some infants with in utero or early-life exposure to SARS-CoV-2 had borderline to low developmental screening scores.

Early SARS-CoV-2 exposure may impact neurodevelopment, especially among infants exposed in utero to symptomatic parents. This is according to a new study led by Sarah Mulkey, M.D., Ph.D., prenatal-neonatal neurologist in the Prenatal Pediatrics Institute at Children’s National Hospital. Dr. Mulkey and team conclude that vaccination and other precautions to reduce early-in-life infection may protect against neurodevelopmental delays. Children with early SARS-CoV-2 exposure should have additional long-term screening for neurodevelopmental delays.

Children’s National Hospital leads the way

The developing brain is vulnerable to both direct and indirect effects of infection during pregnancy and in the early neonatal period. To chart the impact of this exposure, the team created a clinical follow-up protocol in the Congenital Infection Program at Children’s National to chart the development of 34 infants exposed to SARS-CoV-2 in utero or in the neonatal period.

What we hoped to discover

“We conducted this study because we know that infants, when exposed to maternal COVID-19 infection in utero can be exposed to inflammation, fever and an abnormal intrauterine environment. SARS-CoV-2 can also affect the placenta, and in turn, the developing brain,” Dr. Mulkey shared with Healio.

This study aimed to determine if infants with early SARS-CoV-2 exposure developed abnormal neurodevelopment in infancy and the factors that may impact neurodevelopment differences. The study found that some infants with in utero or early-life exposure to SARS-CoV-2 had borderline to low developmental screening scores, most common among babies born to mothers with symptomatic COVID-19. Researchers followed the infants in their first months of life, gauging how the exposure affected their neurologic development. Results were demonstrated using a screening test called the Ages & Stages Questionnaires (ASQ), and those whose scores were borderline or low were most often born to mothers with symptomatic COVID-19.

Why it matters

In conducting this study, the team found that babies born during the pandemic, specifically under these conditions, do, in fact, require additional follow-up in the early stages of life. We may also see more differences in developmental outcomes as children get older.

“Any measure we can take to help prevent infections for mothers in their pregnancy can improve long-term developmental outcomes for children,” says Dr. Mulkey.

Other members of the Children’s National team that contributed to this work include Roberta L. DeBiasi, M.D., M.S.; Meagan E. Williams, M.S.P.H.; Nadia Jadeed, R.N.C.; Anqing Zhang, Ph.D.; and Smitha Israel, B.S.N.

Dr. Mulkey also published a recent article in the American Journal of Obstetrics & Gynecology that found the COVID-19 vaccine may protect pregnant women from SARS-CoV-2 placentitis and stillbirth. This work builds upon Dr. Mulkey’s longitudinal studies on Zika virus infection in pregnancy and long-term impacts on the child, funded by the Thrasher Research Fund and the National Institutes of Health.

Exposure to Zika in utero may produce neurodevelopmental differences

November 30, 2022

“There are still many unanswered questions about the long-term impacts of Zika on children exposed in utero,” says Sarah Mulkey, M.D., Ph.D., a prenatal-neonatal neurologist in the Prenatal Pediatrics Institute at Children’s National Hospital.

Children who are exposed to the Zika virus while in the womb, but who are not subsequently diagnosed with Zika-related birth defects and congenital Zika syndrome (CZS), may still display differences in some aspects of cognitive development, mood and mobility compared to unexposed children, reports a study published in Pediatric Research. These findings suggest that Zika-exposed children may need some additional support and monitoring as they get older.

“There are still many unanswered questions about the long-term impacts of Zika on children exposed in utero,” says Sarah Mulkey, M.D., Ph.D., a prenatal-neonatal neurologist in the Prenatal Pediatrics Institute at Children’s National Hospital and the study’s first author. “These findings are another piece of the puzzle that provides insight into the long-term neurodevelopment of children with prenatal Zika virus exposure. Further evaluation is needed as these children get older.”

It has not been clear how children who were exposed to the Zika virus in the womb during the 2015–2017 epidemic, but who did not develop CZS and serious neurological complications, will develop as they get older.

Dr. Mulkey and colleagues examined the neurodevelopment of 55 children aged 3-5 years who were exposed to Zika in the womb in Sabanalarga, Colombia, and compared them to 70 control children aged 4-5 years who had not been exposed to Zika. Assessments occurred between December 2020 and February 2021. Health professionals tested the children’s motor skills (such as manual dexterity, aiming and catching, and balance) and their readiness for school (including knowledge of colors, letters, numbers and shapes). Parents completed three questionnaires providing information about their child’s cognitive function (such as memory and emotional control), behavioral and physical conditions (such as responsibility and mobility), and their parenting experience (including whether they felt distress).

Parents of Zika-exposed children reported significantly lower levels of mobility and responsibility compared to control children, although differences in cognitive function scores were not significant. Additionally, parents of 6 (11%) Zika-exposed children reported mood problems compared to 1 (1%) of control children, and Zika-exposed parents were significantly more likely to report parental distress.

Professional testing revealed no significant differences in the Zika-exposed children’s manual dexterity, such as their ability to catch an object or post a coin through a slot, compared to the control children. Both Zika-exposed and control children also scored lowly on readiness for school.

The authors highlight that parental responses may have been influenced by the Zika-exposed children’s parents’ perceptions or increased worry about the development of their child. Some differences in results may also have been caused by the age – and therefore developmental – differences between the groups of children.

The authors conclude that while these Zika-exposed children are making progress as they develop, they may need additional support as they prepare to start school.

Dr. Mulkey is committed to studying the long-term neurodevelopmental impacts that viruses like Zika and SARS-CoV-2 have on infants born to mothers who were infected during pregnancy through research with the Congenital Infection Program at Children’s National and in collaboration with colleagues in Colombia.

Multidisciplinary team seeks to reverse epigenetic changes associated with fetal alcohol syndrome disorder

January 21, 2022

The team hopes to optimize and develop treatments that can reverse epigenetic changes in clinical trials, paving the way to make significant progress in the field — something that is lacking to date.

A clinical team joined forces with a research team at Children’s National Hospital to help advance treatments that can improve a child’s development caused by fetal alcohol syndrome disorder (FASDs), which is a group of conditions that can occur in a person who was exposed to alcohol before birth. This boost in collaboration between the bench and clinical hopes to optimize and develop treatments that can reverse epigenetic changes in clinical trials, paving the way to make significant progress in the field — something that is lacking to date.

So far, Children’s National experts have published various pre-clinical studies that identified epigenetic changes caused by alcohol exposure during pregnancy. These changes observed in the pre-clinical models created neuropsychiatric problems like patients with fetal alcohol syndrome disorder. Now, they want to bring such potential treatments effective in pre-clinical models to the bedside.

“As a first step, we are going to test whether the epigenetic changes that were observed in pre-clinical models of FASD are also true in human patients,” said Kazue Hashimoto-Torii, Ph.D., principal investigator of the Center for Neuroscience Research at Children’s National. “We hope a small amount of blood donated by patients with FASD reveal the changes. Meanwhile, my group has also been optimizing drug candidates that reverse the epigenetic changes toward clinical trials.”

Advances in genetics and genomics have led to discoveries about the timing of exposure and developmental outcomes and genetic and epigenetic signatures that may be protective or harmful in terms of how in utero alcohol exposure affects developmental outcomes.

The hold-up in the field

While the exact number of people with FASDs is unknown, the National Institutes of Health estimates that 1% to 5% of the population have FASDs. FASDs has a spectrum of diagnoses that represent a broad range of effects that can be manifested in an individual whose mother drank alcohol during pregnancy. These conditions can affect everyone in different ways and range from mild to severe. Individuals with mild conditions may go undiagnosed. The more affected individuals have comorbid attention-deficit/hyperactivity disorder (ADHD) and behavioral problems that become the focus of clinical encounters. The individual’s health care provider may not recognize the core features as part of FASD.

“Because there is a stigma associated with drinking while pregnant, many providers fail to get this history, and women may be reluctant to offer this information,” said Andrea Gropman, M.D., division chief of Neurodevelopmental Pediatrics and Neurogenetics at Children’s National. “There are subtle and more obvious facial dysmorphology that may help with suspicion or identification, but many individuals do not have these findings.”

The core features may be nonspecific, such as intellectual disabilities and problems with behavior and learning, difficulties with math, memory, attention, judgment and poor impulse control, which are frequent findings in ADHD, autism, learning disorders and other conditions.

“Unless history is taken and FASD is in the differential diagnosis, the diagnosis may not be made,” said Dr. Gropman. “Individuals with FASD may feel stigmatized and opt not to participate in clinical trials.”

As mentioned by Dr. Gropman, stigma can make a patient family be reluctant to seek treatment, and thus the development of treatment for FASD cannot make significant progress to date, Hashimoto-Torii added.

Children’s National Hospital leads the way in an IRB approved study

Researchers at Children’s National have identified a potential drug candidate that reverse the epigenetic changes and may lead to clinical trials. The team is seeking people to participate in an IRB approved study. The study will involve cognitive testing, filling out surveys about current functioning and cheek swab and blood sample to determine if these changes are seen in patients. To participate, subjects must be

Children between the ages 5-12 with prenatal alcohol exposure.
Mother of child recruited above.

For participation, please contact Grace Johnson, research coordinator at to screen for eligibility at 202-476-6034 or gjohnson3@childrensnational.org

Meet the multidisciplinary team with different yet complementary skills in different fields, such as basic science, medical, social sciences, neurology and developmental disabilities, and development, who are working tirelessly to address the complex health problem.

Gropman lab:

Andrea Gropman, M.D., received her medical doctorate degree from the University of Massachusetts Medical School and specializes in neurogenetics, with a focus on mitochondrial disorders and Smith Magenis syndrome. Her latest research focuses on atypical patterns of inheritance, childhood mitochondrial disorders and other inborn errors of metabolism presenting with white matter disease.

Meira Meltzer, M.A., M.S., C.G.C., genetic counselor with a demonstrated history of working in the hospital and healthcare industry. Also skilled in molecular biology, clinical research and medical education. Strong healthcare services professional with a M.S. focused on genetic counseling from Brandeis University.

Cathy Scheiner, M.D., developmental behavioral pediatrician with a special interest in attention-deficit / hyperactivity disorder (ADHD), cerebral palsy and premature infant.

Grace Johnson, research assistant.

Hashimoto-Torii Lab:

Kazue Hashimoto-Torii, Ph.D., received her postdoctoral training in the Pasko Rakic laboratory at Yale University. Her research focuses on neurobehavior problems of children that stem from their environment during development, such as prenatal exposure to alcohol, drug and high-level glucose. A few drug candidates that her lab discovered have been patented and her lab is currently working hard to bring those medicines to bedside.

Satoshi Yamashita, M.D., Ph.D., postdoctoral research fellow skilled in developmental neurobiology. He is a pediatrician with Japanese medical license and received his Ph.D. with iPS cell research for STXBP1 encephalopathy in Japan.

Chiho Yamashita, B.N., research assistant passionate about child disease research. She is a nurse with a Japanese nursing license and worked in the pediatric department in Japan.

Replacing morphine with methadone in the NICU

July 27, 2021

A synthetic analgesic drug, known as methadone, may serve as a better alternative for newborns in the neonatal intensive care unit (NICU) suffering from opioid withdrawal syndrome, according to a commentary published in Pediatric Research.

A synthetic analgesic drug, known as methadone, may serve as a better alternative for newborns in the neonatal intensive care unit (NICU) suffering from opioid withdrawal syndrome, according to a commentary published in Pediatric Research. Some existing literature suggests that methadone may also address painful stimuli that hinders neurodevelopment throughout adulthood, added Johannes van den Anker, M.D., Ph.D., division chief of Clinical Pharmacology at Children’s National Hospital.

The commentary was selected as the Editor’s Focus in Pediatric Research for the June edition, signaling the scientific community as noteworthy to further explore methadone’s potential as an alternative for pharmacologic treatments instead of morphine.

“It is important to define the pharmacokinetics and pharmacodynamics of methadone to treat pain in neonates in intensive care before replacing morphine with methadone. Pre-clinical research shows that the use of methadone might have fewer side effects than morphine,” said Dr. van den Anker. “If this is also the case in the human neonate, then a shift from morphine to methadone might be beneficial. However, first, we need to define what the safe and effective dose of methadone will be for this purpose.”

While there is a need to better understand how newborns and preemies metabolize methadone, there is existing knowledge that this drug minimizes pain. The commentary, too, raises the question for clinicians to possibly consider methadone as a better option to avoid long-term negative neurodevelopmental consequences — such as hypersensitivity to re-injury in later life — usually associated with pain.

The current but limited data out there still provides “exciting and stimulating” information about the possible use of methadone for the treatment of neonatal pain in the NICU, according to Dr. van den Anker. He believes that, in the future, methadone could also serve as mechanism-based analgesia in newborns experiencing pain.

“There needs to be a collaboration between neonatal medicine specialists, pharmacometricians and developmental pharmacologists to assure not only the generation of evidence-based data to determine these optimal dosing regimens, but also to facilitate the implementation of this new knowledge into daily clinical care in neonatal intensive care units across the globe,” added Dr. van den Anker.

The importance of following the Zika population long-term

July 8, 2020

Invited commentary by Sarah Mulkey, M.D., Ph.D., prenatal-neonatal neurologist in the Division of Prenatal Pediatrics at Children’s National Hospital, emphasizes importance of studying the Zika population long term.

A simple measuring tape could be the key to identifying which children could develop neurological and developmental abnormalities from Zika virus exposure during gestation. This is according to an invited commentary published July 7, 2020 in JAMA Network Open and written by Sarah Mulkey, M.D., Ph.D., prenatal-neonatal neurologist in the Division of Prenatal Pediatrics at Children’s National Hospital.

Zika virus (ZIKV), first isolated in 1947 in the Zika Forest in Uganda, made headlines in 2015-2016 for causing a widespread epidemic that spread through parts of North and South America, several islands in the Pacific and parts of Southeast Asia. Although previously linked with no or mild symptoms, researchers discovered during this epidemic that Zika can cross from a pregnant woman to her gestating fetus, leading to a syndrome marked by microcephaly (decreased brain growth), abnormal neurologic tone, vision and hearing abnormalities and joint contractures.

“For the 90% to 95% of ZIKV-exposed infants who fortunately were not born with severe abnormalities at birth and were normocephalic, our hope was that these children would have normal neurodevelopmental outcomes,” Dr. Mulkey writes in the commentary. “Unfortunately, this has not been the case.”

Her commentary expands on a study in the same issue entitled “Association between exposure to antenatal Zika virus and anatomic and neurodevelopmental abnormalities in children” by Cranston et al. In this study, the researchers find that head circumference — a simple measure taken regularly at postnatal appointments in the U.S. — can provide insight into which children were most likely to develop neurologic abnormalities. Their findings show that 68% of those whose head circumference was in the “normal” range at birth developed neurologic problems. Those whose head circumference was at the upper end of this range were significantly less likely to have abnormalities than those at the lower end.

Just this single measurement offers considerable insight into the risk of developing neurologic problems after Zika exposure. However, notes Dr. Mulkey, head circumference growth trajectory is also key. Of the 162 infants whose heads were initially in the normocephalic range at birth, about 10.5% went on to develop microcephaly in the months after birth.

“Because early head growth trajectory is associated with cognitive outcomes in early childhood,” Dr. Mulkey writes, “following the head circumference percentile over time can enable recognition of a child with increased risk for poor outcome who could benefit from early intervention therapies.”

This simple assessment could be significantly augmented with neuroimaging, she adds. The study by Cranston et al., as well as others in the field, have shown that brain imaging often reveals problems in ZIKV-exposed children, such as calcifications and cerebral atrophy, even in those with normal head circumferences. This imaging doesn’t necessarily need to take place at birth, Dr. Mulkey says. Postnatal development of microcephaly, failure to thrive or developmental delay can all be triggers for imaging later on.

Together, Dr. Mulkey says, the study by Cranston et al. and others that focus on ZIKV-exposed children support the need for following these patients long term. Children exposed to ZIKV in the epidemic nearly five years ago are now approaching school age, a time fraught with more complicated cognitive and social demands. Through her own research at Children’s National’s Congenital Zika Virus Program and collaboration with colleagues in Colombia, Dr. Mulkey is following multiple cohorts of ZIKV exposed children as they grow. She recently published a study on neurological abnormalities in one of these cohorts in JAMA Pediatrics in January 2020.

“It’s really important to follow these children as long as possible so we’ll really know the outcomes of this virus,” Dr. Mulkey says.

U.S. DoD awards $2M for study to protect neurological function after cardiac surgery

July 2, 2020

A collaboration between clinical and basic science researchers including Drs. Ishibashi, Hashimoto-Torii, Jonas, and Deutsch, seeks to to understand how caspase enzyme activation plays a role in the development of fine and gross motor skills in children who underwent cardiac surgery for CHD repair.

The U.S. Department of Defense has awarded $2 million to Children’s National Hospital to study how a family of protease enzymes known as caspases may contribute to brain cell degeneration when activated by prolonged anesthesia and cardiopulmonary bypass during cardiac surgery for congenital heart disease.

This U.S. Army Medical Research Acquisition Activity Award, Anesthesia Neurotoxicity in Congenital Heart Disease, is led by principal investigator Nobuyuki Ishibashi, M.D., with both clinical and basic science co-investigators including Kazue Hashimoto-Torii, Ph.D., (Neuroscience), Richard Jonas , M.D., (Cardiovascular Surgery) and Nina Deutsch, M.D., (Anesthesiology).

While the specific cellular and molecular mechanisms of how anesthesia and cardiac surgery impact cortical development are poorly understood, both seem to impact brain growth and development in young children. The most common neurologic deficit seen in children after CHD surgical repair is the impairment of fine and gross motor skills.

Both anesthetic agents and inflammation like that seen as a result of cardiopulmonary bypass have also been shown to contribute to the activation of a specific group of enzymes that play an essential role in the routine (programmed) death of cells: caspases. However, recent pre-clinical research shows that these enzymes may also contribute to other alterations to cells beyond cell death, including making changes to other cell structures. In pre-clinical models, these changes cause impairments to fine and gross motor skills – the same neurological deficits seen in children with CHD who have undergone procedures requiring prolonged anesthesia and cardiopulmonary bypass.

The research team hypothesizes that caspases are extensively activated as a result of cardiac surgery and while that activation is rarely causing reduced numbers of neurons, the changes that caspase enzymes trigger in neurons are contributing to neurological deficits seen in children with CHD after surgery.

While the study focuses specifically on the impacts of cardiac surgery for correction of a heart defect, the findings could have major implications for any pediatric surgical procedure requiring prolonged anesthesia and/or cardiopulmonary bypass.

Stressful pregnancies can leave fingerprint on fetal brain

January 13, 2020

“We were alarmed by the high percentage of pregnant women with a diagnosis of a major fetal heart problem who tested positive for stress, anxiety and depression,” says Catherine Limperopoulos, Ph.D., director of the Center for the Developing Brain at Children’s National and the study’s corresponding author.

When a diagnosis of fetal congenital heart disease causes pregnant moms to test positive for stress, anxiety and depression, powerful imaging can detect impaired development in key fetal brain regions, according to Children’s National Hospital research published online Jan. 13, 2020, in JAMA Pediatrics.

While additional research is needed, the Children’s National study authors say their unprecedented findings underscore the need for universal screening for psychological distress as a routine part of prenatal care and taking other steps to support stressed-out pregnant women and safeguard their newborns’ developing brains.

“We were alarmed by the high percentage of pregnant women with a diagnosis of a major fetal heart problem who tested positive for stress, anxiety and depression,” says Catherine Limperopoulos, Ph.D., director of the Center for the Developing Brain at Children’s National and the study’s corresponding author. “Equally concerning is how prevalent psychological distress is among pregnant women generally. We report for the first time that this challenging prenatal environment impairs regions of the fetal brain that play a major role in learning, memory, coordination, and social and behavioral development, making it all the more important for us to identify these women early during pregnancy to intervene,” Limperopoulos adds.

Congenital heart disease (CHD), structural problems with the heart, is the most common birth defect. Still, it remains unclear how exposure to maternal stress impacts brain development in fetuses with CHD.

The multidisciplinary study team enrolled 48 women whose unborn fetuses had been diagnosed with CHD and 92 healthy women with uncomplicated pregnancies. Using validated screening tools, they found:

65% of pregnant women expecting a baby with CHD tested positive for stress
27% of women with uncomplicated pregnancies tested positive for stress
44% of pregnant women expecting a baby with CHD tested positive for anxiety
26% of women with uncomplicated pregnancies tested positive for anxiety
29% of pregnant women expecting a baby with CHD tested positive for depression and
9% women with uncomplicated pregnancies tested positive for depression

All told, they performed 223 fetal magnetic resonance imaging sessions for these 140 fetuses between 21 and 40 weeks of gestation. They measured brain volume in cubic centimeters for the total brain as well as volumetric measurements for key regions such as the cerebrum, cerebellum, brainstem, and left and right hippocampus.

Maternal stress and anxiety in the second trimester were associated with smaller left hippocampi and smaller cerebellums only in pregnancies affected by fetal CHD. What’s more, specific regions — the hippocampus head and body and the left cerebellar lobe – were more susceptible to stunted growth. The hippocampus is key to memory and learning, while the cerebellum controls motor coordination and plays a role in social and behavioral development.

The hippocampus is a brain structure that is known to be very sensitive to stress. The timing of the CHD diagnosis may have occurred at a particularly vulnerable time for the developing fetal cerebellum, which grows faster than any other brain structure in the second half of gestation, particularly in the third trimester.

“None of these women had been screened for prenatal depression or anxiety. None of them were taking medications. And none of them had received mental health interventions. In the group of women contending with fetal CHD, 81% had attended college and 75% had professional educations, so this does not appear to be an issue of insufficient resources,” Limperopoulos adds. “It’s critical that we routinely to do these screenings and provide pregnant women with access to interventions to lower their stress levels. Working with our community partners, Children’s National is doing just that to help reduce toxic prenatal stress for both the health of the mother and for the future newborns. We hope this becomes standard practice elsewhere.”

Adds Yao Wu, Ph.D., a research associate working with Limperopoulos at Children’s National and the study’s lead author: “Our next goal is exploring effective prenatal cognitive behavioral interventions to reduce psychological distress felt by pregnant women and improve neurodevelopment in babies with CHD.”

In addition to Limperopoulos and Wu , Children’s National study co-authors include Kushal Kapse, MS, staff engineer; Marni Jacobs, Ph.D., biostatistician; Nickie Niforatos-Andescavage, M.D., neonatologist; Mary T. Donofrio, M.D., director, Fetal Heart Program; Anita Krishnan, M.D., associate director, echocardiography; Gilbert Vezina, M.D., director, Neuroradiology Program; David Wessel, M.D., Executive Vice President and Chief Medical Officer; and Adré J. du Plessis, M.B.Ch.B., director, Fetal Medicine Institute. Jessica Lynn Quistorff, MPH, Catherine Lopez, MS, and Kathryn Lee Bannantine, BSN, assisted with subject recruitment and study coordination.

Financial support for the research described in this post was provided by the National Institutes of Health under grant No. R01 HL116585-01 and the Thrasher Research Fund under Early Career award No. 14764.

Congenital heart disease and cortical growth

February 7, 2017

The cover of Science Translational Medicine features a new study of the cellular-level changes in the brain induced by congenital heart disease. Reprinted with permission from AAAS. Not for download

Disruptions in cerebral oxygen supply caused by congenital heart disease have significant impact on cortical growth, according to a research led by Children’s National Health System. The findings of the research team, which include co-authors from the National Institutes of Health, Boston Children’s Hospital and Johns Hopkins School of Medicine, appear on the cover of Science Translational Medicine. The subventricular zone (SVZ) in normal newborns’ brains is home to the largest stockpile of neural stem/progenitor cells, with newly generated neurons migrating from this zone to specific regions of the frontal cortex and differentiating into interneurons. When newborns experience disruptions in cerebral oxygen supply due to congenital heart disease, essential cellular processes go awry and this contributes to reduced cortical growth.

The preliminary findings point to the importance of restoring these cells’ neurogenic potential, possibly through therapeutics, to lessen children’s long-term neurological deficits.

“We know that congenital heart disease (CHD) reduces cerebral oxygen at a time when the developing fetal brain most needs oxygen. Now, we are beginning to understand the mechanisms of CHD-induced brain injuries at a cellular level, and we have identified a robust supply of cells that have the ability to travel directly to the site of injury and potentially provide help by replacing lost or damaged neurons,” says Nobuyuki Ishibashi, M.D., Director of the Cardiac Surgery Research Laboratory at Children’s National, and co-senior study author.

The third trimester of pregnancy is a time of dramatic growth for the fetal brain, which expands in volume and develops complex structures and network connections that growing children rely on throughout adulthood. According to the National Heart, Lung, and Blood Institute, congenital heart defects are the most common major birth defect, affecting 8 in 1,000 newborns. Infants born with CHD can experience myriad neurological deficits, including behavioral, cognitive, social, motor and attention disorders, the research team adds.

Cardiologists have tapped noninvasive imaging to monitor fetal hearts during gestation in high-risk pregnancies and can then perform corrective surgery in the first weeks of life to fix damaged hearts. Long term neurological deficits due to immature cortical development also have emerged as major challenges in pregnancies complicated by CHD.

“I think this is an enormously important paper for surgeons and for children and families who are affected by CHD. Surgeons have been worried for years that the things we do during corrective heart surgery have the potential to affect the development of the brain. And we’ve learned to improve how we do heart surgery so that the procedure causes minimal damage to the brain. But we still see some kids who have behavioral problems and learning delays,” says Richard A. Jonas, M.D., Chief of the Division of Cardiac Surgery at Children’s National, and co-senior study author. “We’re beginning to understand that there are things about CHD that affect the development of the brain before a baby is even born. What this paper shows is that the low oxygen level that sometimes results from a congenital heart problem might contribute to that and can slow down the growth of the brain. The good news is that it should be possible to reverse that problem using the cells that continue to develop in the neonate’s brain after birth.”

Among preclinical models, the spatiotemporal progression of brain growth in this particular model most closely parallels that of humans. Likewise, the SVZ cytoarchitecture of the neonatal preclinical model exposed to hypoxia mimics that of humans in utero and shortly after birth. The research team leveraged CellTracker Green to follow the path traveled by SVZ derived cells and to illuminate their fate, with postnatal SVZ supplying the developing cortex with newly generated neurons. SVZ derived cells were primarily neuroblasts. Superparamagnetic iron oxide nanoparticles supplied answers about long term SVZ migration, with SVZ derived cells making their way to the prefrontal cortex and the somatosensory cortex of the brain.

“We demonstrated that in the postnatal period, newly generated neurons migrate from the SVZ to specific cortices, with the majority migrating to the prefrontal cortex,” says Vittorio Gallo, Ph.D., Director of the Center for Neuroscience Research at Children’s National, and co-senior study author. “Of note, we revealed that the anterior SVZ is a critical source of newborn neurons destined to populate the upper layers of the cortex. We challenged this process through chronic hypoxia exposure, which severely impaired neurogenesis within the SVZ, depleting this critical source of interneurons.”

In the preclinical model of hypoxia as well as in humans, brains were smaller, weighed significantly less and had a significant reduction in cortical gray matter volume. In the prefrontal cortex, there was a significant reduction in white matter neuroblasts. Taken as a whole, according to the study authors, the findings suggest that impaired neurogenesis within the SVZ represents a cellular mechanism underlying hypoxia induced, region specific reduction in immature neurons in the cortex. The prefrontal cortex, the region of the brain that enables such functions as judgment, decision making and problem solving, is most impacted. Impairments in higher order cognitive functions involving the prefrontal cortex are common in patients with CHD.

Congenital heart disease and white matter injury

February 6, 2017

Although recent advances have greatly improved the survival of children with congenital heart disease, up to 55 percent will be left with injury to their brain’s white matter – an area that is critical for aiding connection and communication between various regions in the brain.

What’s known

Eight of every 1,000 children born each year have congenital heart disease (CHD). Although recent advances have greatly improved the survival of these children, up to 55 percent will be left with injury to their brain’s white matter – an area that is critical for aiding connection and communication between various regions in the brain. The resulting spectrum of neurological deficits can have significant costs for the individual, their family and society. Although studies have demonstrated that white matter injuries due to CHD have many contributing factors, including abnormal blood flow to the fetal brain, many questions remain about the mechanisms that cause these injuries and the best interventions.

What’s new

A Children’s National Health System research team combed existing literature, reviewing studies from Children’s as well as other research groups, to develop an article detailing the current state of knowledge on CHD and white matter injury. The scientists write that advances in neuroimaging – including magnetic resonance imaging, magnetic resonance spectroscopy, Doppler ultrasound and diffusion tensor imaging – have provided a wealth of knowledge about brain development in patients who have CHD. Unfortunately, these techniques alone are unable to provide pivotal insights into how CHD affects cells and molecules in the brain. However, by integrating animal models with findings in human subjects and in postmortem human tissue, the scientists believe that it will be possible to find novel therapeutic targets and new standards of care to prevent developmental delay associated with cardiac abnormalities.

For example, using a porcine model, the Children’s team was able to define a strategy for white matter protection in congenital heart surgery through cellular and developmental analysis of different white matter regions. Another study from Children’s combined rodent hypoxia with a brain slice model to replicate the unique brain conditions in neonates with severe and complex congenital heart disease. This innovative animal model provided novel insights into the possible additive effect of preoperative hypoxia on brain insults due to cardiopulmonary bypass and deep hypothermic circulatory arrest.

The Children’s research team also recently published an additional review article describing the key windows of development during which the immature brain is most vulnerable to CHD-related injury.

Questions for future research

Q: Can we create an animal model that recapitulates the morphogenic and developmental aspects of CHD without directly affecting other organs or developmental processes?
Q: What are the prenatal and neonatal cellular responses to CHD in the developing brain?
Q: What are the molecular mechanisms underlying white matter immaturity and vulnerability to CHD, and how can we intervene?
Q: How can we accurately assess the dynamic neurological outcomes of CHD and/or corrective surgery in animal models?
Q: Prenatal or postnatal insults to the developing brain: which is most devastating in regards to developmental and behavioral disabilities?
Q: How can we best extrapolate from, and integrate, neuroimaging findings/correlations in human patients with cellular/molecular approaches in animal models?

Source: Reprinted from Trends in Neurosciences, Vol. 38/Ed. 6, Paul D. Morton, Nobuyuki Ishibashi, Richard A. Jonas and Vittorio Gallo, “Congenital cardiac anomalies and white matter injury,” pp. 353-363, Copyright 2015, with permission from Elsevier.

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