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Catherine Limperopoulos

Stressful pregnancies can leave fingerprint on fetal brain

Catherine Limperopoulos

“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.

Andrea Gropman

$5M in federal funding to help patients with urea cycle disorders

Andrea Gropman

Andrea L. Gropman, M.D.: We have collected many years of longitudinal clinical data, but with this new funding now we can answer questions about these diseases that are meaningful on a day-to-day basis for patients with urea cycle disorders.

An international research consortium co-led by Andrea L. Gropman, M.D., at Children’s National Hospital has received $5 million in federal funding as part of an overall effort to better understand rare diseases and accelerate potential treatments to patients.

Urea cycle disorder, one such rare disease, is a hiccup in a series of biochemical reactions that transform nitrogen into a non-toxic compound, urea. The six enzymes and two carrier/transport molecules that accomplish this essential task reside primarily in the liver and, to a lesser degree, in other organs.

The majority of patients have the recessive form of the disorder, meaning it has skipped a generation. These kids inherit one copy of an abnormal gene from each parent, while the parents themselves were not affected, says Dr. Gropman, chief of the Division of Neurodevelopmental Pediatrics and Neurogenetics at Children’s National. Another more common version of the disease is carried on the X chromosome and affects boys more seriously that girls, given that boys have only one X chromosome.

Regardless of the type of urea cycle disorder, when the urea cycle breaks down, nitrogen converts into toxic ammonia that builds up in the body (hyperammonemia), particularly in the brain. As a result, the person may feel lethargic; if the ammonia in the bloodstream reaches the brain in high concentrations, the person can experience seizures, behavior changes and lapse into a coma.

Improvements in clinical care and the advent of effective medicines have transformed this once deadly disease into a more manageable chronic ailment.

“It’s gratifying that patients diagnosed with urea cycle disorder now are surviving, growing up, becoming young adults and starting families themselves. Twenty to 30 years ago, this never would have seemed conceivable,” Dr. Gropman says. “We have collected many years of longitudinal clinical data, but with this new funding now we can answer questions about these diseases that are meaningful on a day-to-day basis for patients with urea cycle disorders.”

In early October 2019, the National Institutes of Health (NIH) awarded the Urea Cycle Disorders Consortium for which Dr. Gropman is co-principal investigator a five-year grant. This is the fourth time that the international Consortium of physicians, scientists, neuropsychologists, nurses, genetic counselors and researchers has received NIH funding to study this group of conditions.

Dr. Gropman says the current urea cycle research program builds on a sturdy foundation built by previous principal investigators Mendel Tuchman, M.D., and Mark Batshaw, M.D., also funded by the NIH. While previous rounds of NIH funding powered research about patients’ long-term survival prospects and cognitive dysfunction, this next phase of research will explore patients’ long-term health.

Among the topics they will study:

Long-term organ damage. Magnetic resonance elastrography (MRE) is a state-of-the-art imaging technique that combines the sharp images from MRI with a visual map that shows body tissue stiffness. The research team will use MRE to look for early changes in the liver – before patients show any symptoms – that could be associated with long-term health impacts. Their aim is spot the earliest signs of potential liver dysfunction in order to intervene before the patient develops liver fibrosis.

Academic achievement. The research team will examine gaps in academic achievement for patients who appear to be underperforming to determine what is triggering the discrepancy between their potential and actual scholastics. If they uncover issues such as learning difficulties or mental health concerns like anxiety, there are opportunities to intervene to boost academic achievement.

“And if we find many of the patients meet the criteria for depression or anxiety disorders, there are potential opportunities to intervene.  It’s tricky: We need to balance their existing medications with any new ones to ensure that we don’t increase their hyperammonemia risk,” Dr. Gropman explains.

Neurologic complications. The researchers will tap continuous, bedside electroencephalogram, which measures the brain’s electrical activity, to detect silent seizures and otherwise undetectable changes in the brain in an effort to stave off epilepsy, a brain disorder that causes seizures.

“This is really the first time we will examine babies’ brains,” she adds. “Our previous imaging studies looked at kids and adults who were 6 years and older. Now, we’re lowering that age range down to infants. By tracking such images over time, the field has described the trajectory of what normal brain development should look like. We can use that as a background and comparison point.”

In the future, newborns may be screened for urea cycle disorder shortly after birth. Because it is not possible to diagnose it in the womb in cases where there is no family history, the team aims to better counsel families contemplating pregnancy about their possible risks.

Research described in this post was underwritten by the NIH through its Rare Diseases Clinical Research Network.

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.