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Autonomic nervous system appears to function well regardless of mode of childbirth

Late in pregnancy, the human body carefully prepares fetuses for the rigors of life outside the protection of the womb. Levels of cortisol, a stress hormone, ramp up and spike during labor. Catecholamines, another stress hormone, also rise at birth, helping to kick start the necessary functions that the baby will need to regulate breathing, heartbeat, blood pressure and energy metabolism levels at delivery. Oxytocin surges, promoting contractions for the mother during labor and stimulating milk production after the infant is born.

These processes also can play a role in preparing the fetal brain during the transition to life outside the womb by readying the autonomic nervous system and adapting its cerebral connections. The autonomic nervous system acts like the body’s autopilot, taking in information it needs to ensure that internal organs run steadily without willful action, such as ensuring the heart beats and eyelids blink at steady intervals. Its yin, the sympathetic division, stimulates body processes while its yang, the parasympathetic division, inhibits them.

Infants born preterm have reduced autonomic function compared with their full-term peers and also face possible serious neurodevelopmental impairment later in life. But is there a difference in autonomic nervous system function for full-term babies after undergoing labor compared with infants delivered via cesarean section (C-section)?

A team from the Children’s National Inova Collaborative Research Program (CNICA) – a research collaboration between Children’s National in Washington, D.C., and Inova Women’s and Children’s Hospital in Virginia – set out to answer that question in a paper published online July 30, 2019, in Scientific Reports.

They enrolled newborns who had experienced normal, full-term pregnancies and recorded their brain function and heart performance when they were about 2 days old. Infants whose conditions were fragile enough to require observation in the neonatal intensive care unit were excluded from the study. Of 167 infants recruited for the prospective cohort study, 118 newborns had sufficiently robust data to include them in the research.  Of these newborns:

  • 62 (52.5%) were born by vaginal delivery
  • 22 (18.6%) started out with vaginal delivery but ultimately switched to C-section based on failure to progress, failed labor induction or fetal intolerance to labor
  • And 34 (28.8%) were born by elective C-section.

The CNICA research team swaddled infants for comfort and slipped electrode nets over their tiny heads to simultaneously measure heart rate variability and electrocortical function through non-invasive techniques. The team hypothesized that infants who had been exposed to labor would have enhanced autonomic tone and higher cortical electroencephalogram (EEG) power than babies born via C-section.

“In a low-risk group of babies born full-term, the autonomic nervous system and cortical systems appear to function well regardless of whether infants were exposed to labor prior to birth,” says Sarah B. Mulkey, M.D., Ph.D., a fetalneonatal neurologist in the Division of Fetal and Transitional Medicine at Children’s National and the study’s lead author.

However, infants born by C-section following a period of labor had significantly increased accelerations in their heart rates. And the infants born by C-section during labor had significantly lower relative gamma frequency EEG at 25.2 hours old compared with the other two groups studied.

“Together these findings point to a possible increased stress response and arousal difference in infants who started with vaginal delivery and finished delivery with C-section,” Dr. Mulkey says. “There is so little published research about the neurologic impacts of the mode of delivery, so our work helps to provide a normal reference point for future studies looking at high-risk infants, including babies born preterm.”

Because the research team saw little differences in autonomic tone or other EEG frequencies when the infants were 1 day old, future research will explore these measures at different points in the newborns’ early life as well as the role of the sleep-wake cycle on heart rate variability.

In addition to Dr. Mulkey, study co-authors include Srinivas Kota, Ph.D., Rathinaswamy B. Govindan, Ph.D., Tareq Al-Shargabi, MSc, Christopher B. Swisher, BS, Laura Hitchings, BScM, Stephanie Russo, BS, Nicole Herrera, MPH, Robert McCarter, ScD, and Senior Author Adré  J. du Plessis, M.B.Ch.B., MPH, all of Children’s National; and Augustine Eze Jr., MS, G. Larry Maxwell, M.D., and Robin Baker, M.D., all of Inova Women’s and Children’s Hospital.

Financial support for research described in this post was provided by the National Institutes of Health National Center for Advancing Translational Sciences under award numbers UL1TR001876 and KL2TR001877.

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.

Claire Marie Vacher

Placental function linked to brain injuries associated with autism

Claire Marie Vacher

“We saw long-term cerebellar white matter alterations in male experimental models, and behavioral testing revealed social impairments and increased repetitive behaviors, two hallmark features of ASD,” says Claire-Marie Vacher, Ph.D., lead study author.

Allopregnanolone (ALLO), a hormone made by the placenta late in pregnancy, is such a potent neurosteroid that disrupting its steady supply to the developing fetus can leave it vulnerable to brain injuries associated with autism spectrum disorder (ASD), according to Children’s research presented during the Pediatric Academic Societies 2019 Annual Meeting.

In order to more effectively treat vulnerable babies, the Children’s research team first had to tease out what goes wrong in the careful choreography that is pregnancy. According to the Centers for Disease Control and Prevention, about 1 in 10 babies is born preterm, before 37 weeks of gestation. Premature birth is a major risk factor for ASD.

The placenta is an essential and understudied organ that is shared by the developing fetus and the pregnant mother, delivering oxygen, glucose and nutrients and ferrying out waste products. The placenta also delivers ALLO, a progesterone derivative, needed to ready the developing fetal brain for life outside the womb.

ALLO ramps up late in gestation. When babies are born prematurely, their supply of ALLO stops abruptly. That occurs at the same time the cerebellum – a brain region essential for motor coordination, posture, balance and social cognition– typically undergoes a dramatic growth spurt.

“Our experimental model demonstrates that losing placental ALLO alters cerebellar development, including white matter development,” says Anna Penn, M.D., Ph.D., a neonatologist in the divisions of Neonatology and Fetal Medicine, and a developmental neuroscientist at Children’s National. “Cerebellar white matter development occurs primarily after babies are born, so connecting a change in placental function during pregnancy with lingering impacts on later brain development is a particularly striking result.”

The research team created a novel experimental model in which the gene encoding the enzyme responsible for producing ALLO is deleted in the placenta. They compared these preclinical models with a control group and performed whole brain imaging and RNAseq gene expression analyses for both groups.

“We saw long-term cerebellar white matter alterations in male experimental models, and behavioral testing revealed social impairments and increased repetitive behaviors, two hallmark features of ASD,” says Claire-Marie Vacher, Ph.D., lead study author. “These male-specific outcomes parallel the increased risk of brain injury and ASD we see in human babies born prematurely.”

ALLO binds to specific GABA receptors, which control most inhibitory signaling in the nervous system.

“Our findings provide a new way to frame poor placental function: Subtle but significant changes in utero may set in motion neurodevelopmental disorders that children experience later in life,” adds Dr. Penn, the study’s senior author. “Future directions for our research could include identifying new targets in the placenta or brain that could be amenable to hormone supplementation, opening the potential for earlier treatment for high-risk fetuses.”

Pediatric Academic Societies 2019 Annual Meeting presentation

  • “Placental allopregnanolone loss alters postnatal cerebellar development and function.”
    • Sunday, April 28, 2019, 5:15 p.m. to 5:30 p.m. (EST)

Claire-Marie Vacher, Ph.D., lead author; Jackie Salzbank, co-author; Helene Lacaille, co-author; Dana Bakalar, co-author; Jiaqi O’Reilly, co-author; and Anna Penn, M.D., Ph.D., a neonatologist in the divisions of Neonatology and Fetal Medicine, developmental neuroscientist and senior study author.

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.

Robin Steinhorn in the NICU

Coming together as a team for the good of the baby

Robin Steinhorn in the NICU

Children’s National has a new program to care for children who have severe bronchopulmonary dysplasia, a serious complication of preterm birth.

Around the 1-year-old’s crib is a tight circle of smiling adults, and at the foot of his bed is a menagerie of plush animals, each a different color and texture and shape to spark his curiosity and sharpen his intellect.

Gone are the days a newborn with extremely complex medical needs like Elijah would transfer from the neonatal intensive care unit (NICU) to the pediatric intensive care unit and transition through a couple of other hospital units by the time he was discharged. Gone are the days when he’d see a variety of new physician faces at every stop. And gone are the days he’d be confined to his room, divorced from the sights and sounds and scents of the outside world, stimulation that helps little baby’s neural networks grow stronger.

Children’s National has a new program designed to meet the unique needs of children like Elijah who have severe bronchopulmonary dysplasia (BPD), a common complication of preterm birth.

“It’s more forward-thinking – and I mean thinking for the future of each individual baby, and it’s allowing the baby to have one team and one location to take advantage of a deep knowledge of and relationship with that baby and family,” says Robin Steinhorn, M.D. Dr. Steinhorn is senior vice president of the Center for Hospital-Based Specialties and one of Children’s multidisciplinary team members who visited Elijah’s bed twice weekly during his lengthy hospitalization and who continues to see him regularly during outpatient visits.

“The pulmonologist, the neonatologist, the respiratory therapist, the physical therapist, the dietitian, the cardiologist – we all come as a team to work together for the good of the baby,” Dr. Steinhorn adds. “We stick with these babies through thick and thin. We will stick with that baby with this team and this location until they are ready to go home – and beyond.”

BPD, a serious lung condition, mostly affects extremely low birthweight preterm babies whose lungs were designed to continue developing inside the womb until the pregnancy reaches full term. Often born months before their due dates, these extremely vulnerable newborns have immature organs, including the lungs, which are not ready for the task of breathing air. Children’s program targets infants who experience respiratory failure from BPD. The respiratory support required for these infants ranges from oxygen delivered through a nasal cannula to mechanical ventilators.

Robin Steinhorn and Colleague

“It’s more forward-thinking – and I mean thinking for the future of each individual baby, and it’s allowing the baby to have one team and one location to take advantage of a deep knowledge of and relationship with that baby and family,” says Robin Steinhorn, M.D.

About 1 percent of all preterm births are extremely low birthweight, or less than 1,500 grams. Within that group, up to 40 percent will develop BPD. While they represent a small percentage of overall births, these very sick babies need comprehensive, focused care for the first few years of their lives. And some infants with severe BPD also have pulmonary hypertension which, at Children’s National, is co-managed by cardiology and pulmonary specialists.

Children’s BPD team not only focuses on the child’s survival and medical care, they focus on the neurodevelopmental and social care that a baby needs to thrive. From enhanced nutrition to occupational and physical therapy to a regular sleep cycle, the goal is to help these babies achieve their full potential.

“These babies are at tremendous risk for long-term developmental issues. Everything we do is geared to alleviate that,” adds John T. Berger III, M.D., director of Children’s Pulmonary Hypertension Program.

“Our NICU care is more focused, comprehensive and consistent,” agrees Mariam Said, M.D., a neonatologist on the team. “We’re also optimizing the timing of care and diagnostic testing that will directly impact health outcomes.”

Leaving no detail overlooked, the team also ensures that infants have age-appropriate developmental stimuli, like toys, and push for early mobility by getting children up and out of bed and into a chair or riding in a wagon.

“The standard approach is to keep the baby in a room with limited physical or occupational therapy and a lack of appropriate stimulation,” says Geovanny Perez, M.D., a pulmonologist on the team. “A normal baby interacts with their environment inside the home and outside the home. We aim to mimic that within the hospital environment.”

Dr. Steinhorn, who had long dreamed of creating this comprehensive team care approach adds that “it’s been so gratifying to see it adopted and embraced so quickly by Children’s NICU caregivers.”