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False negatives: Delayed Zika effects in babies who appeared normal at birth

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Colombian infants exposed to Zika virus in the womb showed neurodevelopmental delays as toddlers, despite having “normal” brain imaging and head circumference at birth, a finding that underscores the importance of long-term neurodevelopmental follow-up for Zika-exposed infants.

Colombian infants exposed to Zika virus in the womb showed neurodevelopmental delays as toddlers, despite having “normal” brain imaging and head circumference at birth, a finding that underscores the importance of long-term neurodevelopmental follow-up for Zika-exposed infants, according to a cohort study published online Jan. 6, 2020, in JAMA Pediatrics.

“These infants had no evidence of Zika deficits or microcephaly at birth. Neurodevelopmental deficits, including declines in mobility and social cognition, emerged in their first year of life even as their head circumference remained normal,” says Sarah B. Mulkey, M.D. Ph.D., a fetal/neonatal neurologist at Children’s National Hospital and the study’s first author. “About one-third of these newborns who underwent postnatal head ultrasound had nonspecific imaging results, which we believe are the first published results finding a link between subtle brain injuries and impaired neuromotor development in Zika-exposed children.”

The multi-institutional research group led by Children’s National enrolled pregnant women in Atlántico Department, which hugs the Caribbean coast of Colombia, who had been exposed to Zika, and performed a series of fetal magnetic resonance images (MRI) and ultrasounds as their pregnancies progressed.

Even though their mothers had laboratory-confirmed Zika infections, 77 out of 82 of their offspring were born with no sign of congenital Zika syndrome, a constellation of birth defects that includes severe brain abnormalities, eye problems and congenital contractures, and 70 underwent additional testing of neurodevelopment during infancy. These apparently normal newborns were born between Aug. 1, 2016, and Nov. 30, 2017, at the height of the Zika epidemic, and had normal head circumference.

When they were 4 to 8 months or 9 to 18 months of age, the infants’ neurodevelopment was evaluated using two validated tools, the Warner Initial Developmental Evaluation of Adaptive and Functional Skills (a 50-item test of such skills as self-care, mobility, communication and social cognition) and the Alberta Infant Motor Scale (a motor examination of infants in prone, supine, sitting and standing positions). Some infants were assessed during each time point.

Women participating in the study were highly motivated, with 91% following up with appointments, even if it meant traveling hours by bus. In addition to Children’s National faculty traveling to Colombia to train staff how to administer the screening instruments, videotaped assessments, MRIs and ultrasounds were read, analyzed and scored at Children’s National. According to the study team, the U.S. scoring of Alberta Infant Motor Scale tests administered in Colombia is also unprecedented for a research study and offers the potential of remote scoring of infants’ motor skill maturity in regions of the world where pediatric specialists, like child neurologists, are lacking.

“Normally, neurodevelopment in infants and toddlers continues for years, building a sturdy neural network that they later use to carry out complex neurologic and cognitive functions as children enter school,” Dr. Mulkey adds. “Our findings underscore the recommendations by the Centers for Disease Control and Prevention (CDC) that all infants exposed to Zika in the womb undergo long-term follow-up, providing an opportunity to intervene earlier.”

An accompanying editorial by CDC staffers concurs, saying the study reported “intriguing data” that add “to the growing evidence of the need for long-term follow-up for all children with Zika virus exposure in utero to ensure they receive the recommended clinical evaluations even when no structural defects are identified at birth.”

In addition to Dr. Mulkey, study co-authors include Margarita Arroyave-Wessel, MPH, Dorothy I. Bulas, M.D., chief of Diagnostic Imaging and Radiology, JiJi Jiang, MS, Stephanie Russo, BS, Robert McCarter, ScD, research section head, design and biostatistics,  Adré J. du Plessis, M.B.Ch.B., MPH, chief of the Division of Fetal and Transitional Medicine, and co-Senior Author, Roberta L. DeBiasi, MD, MS, chief of the Division of Pediatric Infectious Diseases, all of Children’s National; Colleen Peyton, PT, DPT, of Northwestern University; Yamil Fourzali, M.D., of Sabbag Radiologos, Barranquilla, Colombia; Michael E. Msall, M.D., of University of Chicago Comer Children’s Hospital; and co-Senior Author, Carlos Cure, M.D., BIOMELab, Barranquilla, Colombia.

Funding for the research described in this post was provided by the Thrasher Research Fund, the National Institutes of Health under award Nos. UL1TR001876 and KL2TR001877, and the Leadership Education in Neurodevelopmental and Related Disorders Training Program under grant HRSA/MCHB T73 MC11047.

doctor checking pregnant woman's belly

Novel approach to detect fetal growth restriction

doctor checking pregnant woman's belly

Morphometric and textural analyses of magnetic resonance imaging can point out subtle architectural deviations associated with fetal growth restriction during the second half of pregnancy, a first-time finding that has the promise to lead to earlier intervention.

Morphometric and textural analyses of magnetic resonance imaging (MRI) can point out subtle architectural deviations that are associated with fetal growth restriction (FGR) during the second half of pregnancy. The first-time finding hints at the potential to spot otherwise hidden placental woes earlier and intervene in a more timely fashion, a research team led by Children’s National Hospital faculty reports in Pediatric Research.

“We found reduced placental size, as expected, but also determined that the textural metrics are accelerated in FGR when factoring in gestational age, suggesting premature placental aging in FGR,” says Nickie Andescavage, M.D., a neonatologist at Children’s National and the study’s lead author. “While morphometric and textural features can discriminate placental differences between FGR cases with and without Doppler abnormalities, the pattern of affected features differs between these sub-groups. Of note, placental insufficiency with abnormal Doppler findings have significant differences in the signal-intensity metrics, perhaps related to differences of water content within the placenta.”

The placenta, an organ shared by the pregnant woman and the developing fetus, delivers oxygen and nutrients to the developing fetus and ferries away waste products. Placental insufficiency is characterized by a placenta that develops poorly or is damaged, impairing blood flow, and can result in still birth or death shortly after birth. Surviving infants may be born preterm or suffer early brain injury; later in life, they may experience cardiovascular, metabolic or neuropsychiatric problems.

Because there are no available tools to help clinicians identify small but critical changes in placental architecture during pregnancy, placental insufficiency often is found after some damage is already done. Typically, it is discovered when FGR is diagnosed, when a fetus weighs less than 9 of 10 fetuses of the same gestational age.

“There is a growing appreciation for the prenatal origin of some neuropsychiatric disorders that manifest years to decades later. Those nine months of gestation very much define the breath of who we later become as adults,” says Catherine Limperopoulos, Ph.D., director of MRI Research of the Developing Brain at Children’s National and the study’s senior author. “By identifying better biomarkers of fetal distress at an earlier stage in pregnancy and refining our imaging toolkit to detect them, we set the stage to be able to intervene earlier and improve children’s overall outcomes.”

The research team studied 32 healthy pregnancies and compared them with 34 pregnancies complicated by FGR. These women underwent up to two MRIs between 20 weeks to 40 weeks gestation. They also had abdominal circumference, fetal head circumference and fetal femur length measured as well as fetal weight estimated.

In pregnancies complicated by FGR, placentas were smaller, thinner and shorter than uncomplicated pregnancies and had decreased placental volume. Ten of 13 textural and morphometric features that differed between the two groups were associated with absolute birth weight.

“Interestingly, when FGR is diagnosed in the second trimester, placental volume, elongation and thickness are significantly reduced compared with healthy pregnancies, whereas the late-onset of FGR only affects placental volume,” Limperopoulos adds. “We believe with early-onset FGR there is a more significant reduction in the developing placental units that is detected by gross measures of size and shape. By the third trimester, the overall shape of the placenta seems to have been well defined so that primarily volume is affected in late-onset FGR.”

In addition to Dr. Andescavage and Limperopoulos, study co-authors include Sonia Dahdouh, Sayali Yewale, Dorothy Bulas, M.D., chief of the Division of Diagnostic Imaging and Radiology, and Biostatistician, Marni Jacobs, Ph.D., MPH, all of Children’s National; Sara Iqbal, of MedStar Washington Hospital Center; and Ahmet Baschat, of Johns Hopkins Center for Fetal Therapy.

Financial support for research described in this post was provided by the National Institutes of Health under award number 1U54HD090257, R01-HL116585, UL1TR000075 and KL2TR000076, and the Clinical-Translational Science Institute-Children’s National.

illustration of brain showing cerebellum

Focusing on the “little brain” to rescue cognition

illustration of brain showing cerebellum

Research faculty at Children’s National in Washington, D.C., with colleagues recently published a review article in Nature Reviews Neuroscience that covers the latest research about how abnormal development of the cerebellum leads to a variety of neurodevelopmental disorders.

Cerebellum translates as “little brain” in Latin. This piece of anatomy – that appears almost separate from the rest of the brain, tucked under the two cerebral hemispheres – long has been known to play a pivotal role in voluntary motor functions, such as walking or reaching for objects, as well as involuntary ones, such as maintaining posture.

But more recently, says Aaron Sathyanesan, Ph.D., a postdoctoral research fellow at the Children’s Research Institute, the research arm of Children’s National  in Washington, D.C., researchers have discovered that the cerebellum is also critically important for a variety of non-motor functions, including cognition and emotion.

Sathyanesan, who studies this brain region in the laboratory of Vittorio Gallo, Ph.D., Chief Research Officer at Children’s National and scientific director of the Children’s Research Institute, recently published a review article with colleagues in Nature Reviews Neuroscience covering the latest research about how altered development of the cerebellum contributes to a variety of neurodevelopmental disorders.

These disorders, he explains, are marked by problems in the nervous system that arise while it’s maturing, leading to effects on emotion, learning ability, self-control, or memory, or any combination of these. They include diagnoses as diverse as intellectual disability, autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder and Down syndrome.

“One reason why the cerebellum might be critically involved in each of these disorders,” Sathyanesan says, “is because its developmental trajectory takes so long.”

Unlike other brain structures, which have relatively short windows of development spanning weeks or months, the principal cells of the cerebellum – known as Purkinje cells – start to differentiate from stem cell precursors at the beginning of the seventh gestational week, with new cells continuing to appear until babies are nearly one year old.  In contrast, cells in the neocortex, a part of the brain involved in higher-order brain functions such as cognition, sensory perception and language is mostly finished forming while fetuses are still gestating in the womb.

This long window for maturation allows the cerebellum to make connections with other regions throughout the brain, such as extensive connections with the cerebral cortex, the outer layer of the cerebrum that plays a key role in perception, attention, awareness, thought, memory, language and consciousness. It also allows ample time for things to go wrong.

“Together,” Sathyanesan says, “these two characteristics are at the root of the cerebellum’s involvement in a host of neurodevelopmental disorders.”

For example, the review article notes, researchers have discovered both structural and functional abnormalities in the cerebellums of patients with ASD. Functional magnetic resonance imaging (MRI), an imaging technique that measures activity in different parts of the brain, suggests that significant differences exist between connectivity between the cerebellum and cortex in people with ASD compared with neurotypical individuals. Differences in cerebellar connectivity are also evident in resting-state functional connectivity MRI, an imaging technique that measures brain activity in subjects when they are not performing a specific task. Some of these differences appear to involve patterns of overconnectivity to different brain regions, explains Sathyanesan; other differences suggest that the cerebellums of patients with ASD don’t have enough connections to other brain regions.

These findings could clarify research from Children’s National and elsewhere that has shown that babies born prematurely often sustain cerebellar injuries due to multiple hits, including a lack of oxygen supplied by infants’ immature lungs, he adds. Besides having a sibling with ASD, premature birth is the most prevalent risk factor for an ASD diagnosis.

The review also notes that researchers have discovered structural changes in the cerebellums of patients with Down syndrome, who tend to have smaller cerebellar volumes than neurotypical individuals. Experimental models of this trisomy recapitulate this difference, along with abnormal connectivity to the cerebral cortex and other brain regions.

Although the cerebellum is a pivotal contributor toward these conditions, Sathyanesan says, learning more about this brain region helps make it an important target for treating these neurodevelopmental disorders. For example, he says, researchers are investigating whether problems with the cerebellum and abnormal connectivity could be lessened through a non-invasive form of brain stimulation called transcranial direct current stimulation or an invasive one known as deep brain stimulation. Similarly, a variety of existing pharmaceuticals or new ones in development could modify the cerebellum’s biochemistry and, consequently, its function.

“If we can rescue the cerebellum’s normal activity in these disorders, we may be able to alleviate the problems with cognition that pervade them all,” he says.

In addition to Sathyanesan and Senior Author Gallo, Children’s National study co-authors include Joseph Scafidi, D.O., neonatal neurologist; Joy Zhou and Roy V. Sillitoe, Baylor College of Medicine; and Detlef H. Heck, of University of Tennessee Health Science Center.

Financial support for research described in this post was provided by the National Institute of Neurological Disorders and Stroke under grant numbers 5R01NS099461, R01NS089664, R01NS100874, R01NS105138 and R37NS109478; the Hamill Foundation; the Baylor College of Medicine Intellectual and Developmental Disabilities Research Center under grant number U54HD083092; the University of Tennessee Health Science Center (UTHSC) Neuroscience Institute; the UTHSC Cornet Award; the National Institute of Mental Health under grant number R01MH112143; and the District of Columbia Intellectual and Developmental Disabilities Research Center under grant number U54 HD090257.

Nickie Andescavage

To understand the preterm brain, start with the fetal brain

Nickie Andescavage

“My best advice to future clinician-scientists is to stay curious and open-minded; I doubt I could have predicted my current research interest or described the path between the study of early oligodendrocyte maturation to in vivo placental development, but each experience along the way – both academic and clinical – has led me to where I am today,” Nickie Andescavage, M.D., writes.

Too often, medical institutions erect an artificial boundary between caring for the developing fetus inside the womb and caring for the newborn whose critical brain development continues outside the womb.

“To improve neonatal outcomes, we must transform our current clinical paradigms to begin treatment in the intrauterine period and continue care through the perinatal transition through strong collaborations with obstetricians and fetal-medicine specialists,” writes Nickie Andescavage, M.D., an attending in Neonatal-Perinatal Medicine at Children’s National.

Dr. Andescavage’s commentary was published online March 25, 2019, in Pediatrics Research and accompanies recently published Children’s research about differences in placental development in the setting of placental insufficiency. Her commentary is part of a new effort by Nature Publishing Group to spotlight research contributions from early career investigators.

The placenta, an organ shared by a pregnant woman and the developing fetus, plays a critical but underappreciated role in the infant’s overall health. Under the mentorship of Catherine Limperopoulos, Ph.D., director of MRI Research of the Developing Brain, and Adré J. du Plessis, M.B.Ch.B., MPH, chief of the Division of Fetal and Transitional Medicine, Dr. Andescavage works with interdisciplinary research teams at Children’s National to help expand that evidence base. She has contributed to myriad published works, including:

While attending Cornell University as an undergraduate, Dr. Andescavage had an early interest in neuroscience and neurobehavior. As she continued her education by attending medical school at Columbia University, she corroborated an early instinct to work in pediatrics.

It wasn’t until the New Jersey native began pediatric residency at Children’s National that those complementary interests coalesced into a focus on brain autoregulation and autonomic function in full-term and preterm infants and imaging the brains of both groups. In normal, healthy babies the autonomic nervous system regulates heart rate, blood pressure, digestion, breathing and other involuntary activities. When these essential controls go awry, babies can struggle to survive and thrive.

“My best advice to future clinician-scientists is to stay curious and open-minded; I doubt I could have predicted my current research interest or described the path between the study of early oligodendrocyte maturation to in vivo placental development, but each experience along the way – both academic and clinical – has led me to where I am today,” Dr. Andescavage writes in the commentary.