Tag Archive for: oxygen

preterm baby

Validating a better way to stratify BPD risk in vulnerable newborns

preterm baby

Factoring in the total number of days that extremely preterm infants require supplemental oxygen and tracking this metric for weeks longer than usual improves clinicians’ ability to predict respiratory outcomes according to bronchopulmonary dysplasia severity.

Factoring in the total number of days that extremely preterm infants require supplemental oxygen and tracking this metric for weeks longer than usual improves clinicians’ ability to predict respiratory outcomes according to bronchopulmonary dysplasia (BPD) severity, a research team led by Children’s National Hospital writes in Scientific Reports. What’s more, the researchers defined a brand-new category (level IV) for newborns who receive supplemental oxygen more than 120 days as a reliable way to predict which infants are at the highest risk of returning to the hospital due to respiratory distress after discharge.

About 1 in 10 U.S. infants is born preterm, before 37 weeks gestation, according to the Centers for Disease Control and Prevention. That includes extremely preterm infants who weigh about 1 lb. at birth. These very low birthweight newborns have paper thin skin, frail hearts and lungs that are not yet mature enough to deliver oxygen throughout the body as needed. Thanks to advances in neocritical care, an increasing number of them survive prematurity, and many develop BPD, a chronic lung disease characterized by abnormal development of the lungs and pulmonary vasculature.

“About half of the babies born prematurely will come back to the hospital within the first year of life with a respiratory infection. The key is identifying them and, potentially, preventing complications in this high-risk population,” says Gustavo Nino, M.D., a Children’s National pulmonologist and the study’s lead author.

For decades, the most common way to stratify BPD risk in these vulnerable newborns has been to see if they require supplemental oxygen at 36 weeks corrected gestational age.

“The problem with this classification is it doesn’t take into account the very premature babies who are on oxygen for much longer than other babies. So, we asked the question: Can we continue risk stratification beyond 36 weeks in order to identify a subset of babies who are at much higher risk of complications,” Dr. Nino says.

The longitudinal cohort study enrolled 188 infants born extremely preterm who were admitted to the neonatal intensive care unit (NICU) at Children’s National and tracked their data for at least 12 months after discharge. The team used a multidimensional approach that tracked duration of supplemental oxygen during the newborns’ NICU stay as well as scoring lung imaging as an independent marker of BPD severity. To validate the findings, these U.S.-born newborns were matched with 130 infants who were born preterm and hospitalized at two NICUs located in Bogotá, Colombia.

“Babies who are born very preterm and require oxygen beyond 120 days should have expanded ventilation of the lungs and cardiovascular pulmonary system before going home,” he notes. “We need to identify these newborns and optimize their management before they are discharged.”

And, the babies with level IV BPD risk need a different type of evaluation because the complications they experience – including pulmonary hypertension – place them at the highest risk of developing sleep apnea and severe respiratory infection, especially during the first year of life.

“The earlier we identify them, the better their outcome is likely to be,” Dr. Nino says. “We really need to change the risk stratification so we don’t call them all ‘severe’ and treat them the same when there is a subset of newborns who clearly are at a much higher risk for experiencing respiratory complications after hospital discharge.”

In addition to Dr. Nino, Children’s National study co-authors include Awais Mansoor, Ph.D., staff scientist at the Sheikh Zayed Institute for Pediatric Surgical Innovation (SZI); Geovanny F. Perez, M.D., pediatric pulmonologist; Maria Arroyo, M.D., pulmonologist; Xilei Xu Chen, M.D., postdoctoral fellow; Jered Weinstock, pediatric pulmonary fellow; Kyle Salka, MS, research technician; Mariam Said, M.D., neonatologist, and Marius George Linguraru, DPhil, MA, MSc, SZI principal investigator and senior author. Additional co-authors include Ranniery Acuña-Cordero, Universidad Militar Nueva Granada, Bogotá, Colombia; and Monica P. Sossa-Briceño and Carlos E. Rodríguez-Martínez, both of Universidad Nacional de Colombia.

Funding for research described in this post was provided by the National Institutes of Health (NIH) under award Nos. HL145669, AI130502 and HL141237. In addition, the NIH has awarded Dr. Nino an RO1 grant to continue this research.

newborn in incubator

A bronchopulmonary dysplasia primer to guide clinicians and researchers

newborn in incubator

Six months in the writing, the “Bronchopulmonary Dysplasia Primer” published recently by Nature Reviews will be the gold standard review on this topic for years to come.

The term bronchopulmonary dysplasia, or BPD, was first coined in 1967 to describe a chronic lung disease of preterm newborns after treatment with supplemental oxygen via mechanical ventilation in an effort to save their lives. Back then, infants had 50-50 odds of surviving.

In the intervening years, survival has improved and the characteristics of BPD have evolved. Now, BPD is the most common complication of preterm birth for infants born at fewer than 28 weeks’ gestation, as more and more newborns survive premature birth. Hence, the primer.

“The contributing authors are some of the biggest thinkers on this topic,” says Robin H. Steinhorn, M.D., senior vice president, Center for Hospital-Based Specialties, at Children’s National Hospital and author of the section about BPD diagnosis, screening and prevention. “This document will guide clinical education and investigators in the field of BPD. I anticipate this will be the definitive review article on the subject for the next several years.”

Gestational age and low birth weight remain the most potent predictors of BPD. Some 50,000 extremely low gestational age newborns are born each year in the U.S. About 35% will develop some degree of BPD, according to the primer authors.

These newborns are introduced to life outside the womb well before their lungs are ready. Indeed, the pulmonary surfactants needed for normal lung function – a complex mixture of phospholipids that reduce surface tension within the lungs – don’t differentiate until late in pregnancy. Infants who persistently need respiratory support after the 14th day of life are at the highest risk of being diagnosed with BPD at 36 weeks, the coauthors note.

A number of complicating factors can come into play, including maternal diet; fetal exposure to maternal smoking and infection; structural issues such as pre-eclampsia; acute injury from mechanical ventilation and supplemental oxygen; as well as the body’s halting efforts to repair injured, inflamed lung tissue.

“The good news is the number of the smallest and youngest preterm infants who survive extreme preterm birth has steadily increased. Neonatal intensive care units, like our award-winning NICU, now routinely care for babies born at 22 weeks’ gestation,” Dr. Steinhorn says.

Treatment strategies include:

  • Reducing exposure to intubation and ventilation.
  • Leveraging respiratory stimulants, like caffeine.
  • Postnatal steroid therapy.

“Children’s National Hospital is the only center in our immediate region that provides comprehensive care for infants and children with severe BPD,” Dr. Steinhorn adds. “As the population of vulnerable and fragile infants has grown, we have invested in the equipment and the personnel – including at the Hospital for Sick Children Pediatric Center (HSC) – to create a very safe and supportive environment that improves survival and quality of life.”

Some preterm infants spend their first 9 to 10 months of life at Children’s National, and their days are filled with concentrated physical, occupational and speech therapy, as well as music and play therapy to hasten their rehabilitation.

Once their medical condition stabilizes, they transition to HSC to focus more intently on rehabilitation.

“We see HSC as filling a very important role in their care. When our children graduate to HSC, they are going for ongoing care of their lung disease, but also their ongoing rehabilitation. At HSC, they focus on creating the most normal life that we can possibly create and, over time, that is a life free of ventilators and tracheostomy tubes.”

In addition to Dr. Steinhorn, BPD Primer co-authors include Bernard Thébaud, Children’s Hospital of Eastern Ontario; Kara N. Goss, University of Wisconsin-Madison; Matthew Laughon, The University of North Carolina at Chapel Hill; Jeffrey A. Whitsett and Alan H. Jobe, Cincinnati Children’s Hospital Medical Center; Steven H. Abman, Children’s Hospital Colorado;  Judy L. Aschner, Joseph M. Sanzari Children’s Hospital; Peter G. Davis, The Royal Women’s Hospital; Sharon A. McGrath- Morrow, Johns Hopkins University School of Medicine; and Roger F. Soll, University of Vermont.

Financial support for the research described in this post was provided by the National Institutes of Health under grant Nos. U01HL122642, U01HL134745, RO1HL68702, R01HL145679, U01HL12118-01 and K24 HL143283; the Australian National Health and Medical Research Council; the Canadian Institute for Health Research; Stem Cell Network and the Ontario Institute for Regenerative Medicine.

Bella when she was sick

Preserving brain function by purposely inducing strokes

Bella when she was sick

Born to young parents, no prenatal testing had suggested any problems with Bella’s brain. But just a few hours after birth, Bella suffered her first seizure – one of many that would follow in the ensuing days. After brain imaging, her doctors in Iowa diagnosed her with hemimegalencephaly.

Strokes are neurologically devastating events, cutting off life-sustaining oxygen to regions of the brain. If these brain tissues are deprived of oxygen long enough, they die, leading to critical loss of function – and sometimes loss of life.

“As physicians, we’re taught to prevent or treat stroke. We’re never taught to inflict it,” says Taeun Chang, M.D., director of the Neonatal Neurology and Neonatal Neurocritical Care Program at Children’s National Hospital.

That’s why a treatment developed at Children’s National for a rare brain condition called hemimegalencephaly is so surprising, Dr. Chang explains. By inflicting controlled, targeted strokes, Children’s National physician-researchers have treated five newborns born with intractable seizures due to hemimegalencephaly before they’re eligible for epilepsy surgery, the standard of care. In the four surviving infants, the procedures drastically reduced or completely relieved the infants of hemimegalencephaly’s characteristic, uncontrollable seizures.

The most recent patient to receive this life-changing procedure is Bella, a 13-month-old from Iowa whose treatment at Children’s National began within her second week of life. Born to young parents, no prenatal testing had suggested any problems with Bella’s brain. But just a few hours after birth, Bella suffered her first seizure – one of many that would follow in the ensuing days. After brain imaging, her doctors in Iowa diagnosed her with hemimegalencephaly.

A congenital condition occurring in just a handful of children born worldwide each year, hemimegalencephaly is marked by one brain hemisphere growing strikingly larger and dysplastic than the other, Dr. Chang explains. This abnormal half of the brain is highly vascularized, rippled with blood vessels needed to support the seizing brain. The most conspicuous symptoms of hemimegalencephaly are the numerous seizures that it causes, sometimes several in the course of an hour, which also may prevent the normal half of the brain from developing and learning.

Prior studies suggest early surgery achieves better developmental outcomes with one study reporting as much as a drop of 10-20 IQ points with every month delay in epilepsy surgery.

The standard treatment for unilateral megalencephaly is a dramatic procedure called a hemispherectomy, in which surgeons remove and disconnect the affected half of the brain, allowing the remaining half to take over its neurological duties. However, Dr. Chang says, implementing this procedure in infants younger than 3 months of age is highly dangerous.  Excessive, potentially fatal blood loss is likely in infants younger than 3 months who have a highly vascularized brain in the setting of an immature coagulation system. That leaves their doctors with no choice but to wait until these infants are at least 3 months old, when they are more likely to survive the surgery.

However, five years ago, Dr. Chang and her colleagues came up with a different idea when a newborn continued to have several seizures per hour despite multiple IV seizure medications: Because strokes cause irreversible tissue death, it might be possible to effectively incapacitate the enlarged hemisphere from within by inflicting a stroke on purpose. At the very least, this “functional embolization” might buy time for a traditional hemispherectomy, and slow or halt ongoing brain damage until the infants are able to withstand surgery. Ideally, this procedure may be all some children need, knocking out the offending hemisphere completely so they’d never need a hemispherectomy, which has late complications, such as hydrocephalus.

A pediatrician friend of Bella’s paternal grandparents read a story on Children’s National website about Darcy, another baby who’d received functional embolization a year earlier and was doing well. She contacted Dr. Chang to see if the procedure would be appropriate for Bella.

Within days, Bella and her family headed to Washington, D.C., to prepare for functional embolization herself. Within the first weeks of life, Bella underwent three separate procedures, each three to four hours long. Under real-time fluoroscopic and angiographic guidance, interventional neuroradiologist Monica Pearl, M.D., threaded a micro-catheter up from the baby’s femoral artery through the complex network of blood vessels all the way to her brain. There, in targeted branches of her cerebral arteries, Dr. Pearl strategically placed liquid embolic agent to obstruct blood flow to the abnormal half of Bella’s brain.

Immediately after the first procedure, the team had to contend with the same consequences that come after any stroke: brain swelling that can cause bleeding and herniation, complicated further by the already enlarged hemisphere of Bella’s brain. Using neuroprotective strategies learned from treating hundreds of brain-injured newborns, the neonatal neurocritical care team and the neonatal intensive care unit (NICU) minimized the brain swelling and protected the normal half of the brain by tightly controlling the brain temperature, her sugar and electrolyte levels, her blood pressure and coagulation system.

As the brain tissue in the oversized hemisphere died, so did the seizures that had plagued Bella since birth. She has not had a seizure since she left Children’s National more than one year ago. Her adoptive parents report that Bella is hitting many of the typical developmental milestones for her age: She’s getting ready to walk, blowing kisses and saying a few words. Physical, speech and occupational therapy will keep her moving in the right direction, Dr. Chang says.

“We believe that Children’s National is the only place in the world that’s treating newborns in this way to preserve their futures,” Dr. Chang says. “We’re privileged to be able to care for Bella and other kids with this rare condition.”

Bella’s transfer and successful procedures required the support and collective efforts of many within the hospital organization including William D. Gaillard, M.D., and his surgical epilepsy team; interventional neuroradiology with Dr. Monica Pearl; Neurosurgery; Neonatology and the NICU; social work; and even approval from Robin Steinhorn, M.D., senior vice president of the Center for Hospital-Based Specialties, and David Wessel, M.D., executive vice president and Chief Medical Officer.

“While obvious credit goes to the medical team who saved Bella’s future and the neonatal intensive care nurses who provided exceptional, intensive, one-on-one care, Bella’s team of supporters extend to all levels within our hospital,” Dr. Chang adds.

Also read:

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.

spectrometer output

Understanding low cardiac output after surgery

spectrometer output

Rafael Jaimes, Ph.D., created an algorithm that is being tested in a pre-clinical model to characterize the light absorbance spectrum from different heart regions using a spectrometer.

After intense cardiac surgery, sometimes a patient’s heart is unable to effectively deliver oxygenated blood and nutrients throughout the recovering body. Known as inadequate or low cardiac output, the condition occurs in about a quarter of patients following surgery with cardiopulmonary bypass, including young children who require complex procedures to correct congenital heart defects at Children’s National Health System.

Researchers at the Sheikh Zayed Institute for Pediatric Surgical Innovation are exploring several facets of this challenge, with the goal of better understanding post-operative recovery trajectories in pediatric patients. Rafael Jaimes, Ph.D., a staff scientist at the institute, leads this work to identify when and how low cardiac output occurs, pinpoint the physical hallmarks of this condition and use that information to prevent long term damage and complications after surgery, including cardiac arrest.

“More research needs to be done to understand the cause of this overarching and multi-faceted syndrome,” says Dr. Jaimes. “I’m interested in understanding how metabolic insufficiency contributes to this condition, and also exploring how we can use current imaging and diagnostic tools to measure, track and treat the insufficiencies that contribute to low cardiac output.”

Tracking inadequate oxygen and nutrient delivery to the parts of the heart that have been repaired is one avenue under exploration. Currently, a cardiac-specific real-time device to measure the oxygen state of the heart, while a patient is in post-operative critical care, is under development.

The heart’s complexity has made using current oxygen measurement devices, such as spectrometers, very difficult. To date no tool exists that effectively screens out artifacts and noise to allow clear visualization. However, during his post-doctoral work, Dr. Jaimes has created a new algorithm that may be the first of its kind to accomplish this feat.

This work on low cardiac output recently received a Congenital Heart Defect Research Award, which is a collaborative program of the Children’s Heart Foundation and the American Heart Association that supports innovative research, seeking to understand and treat congenital heart defects.

A new research study will build on his previous studies by using the algorithm to characterize the absorbance spectrum from different heart regions in a pre-clinical model. The data collected will serve as the baseline for development of a prototype spectrometer software, capable of tracking changes in heart oxygenation before, during and after surgery.

The end goal is to more effectively identify when parts of the heart are deprived of oxygen and nutrients and prevent resulting impacts on cardiac metabolism and output. Doing so will decrease short term mortality and morbidity and may also improve circulation systemically, potentially reducing long term health impacts of reduced oxygenation, such as neurodevelopmental disorders.

newborn in incubator

In HIE lower heart rate variability signals stressed newborns

newborn in incubator

In newborns with hypoxic-ischemic encephalopathy (HIE), lower heart rate variability correlates with autonomic manifestations of stress shortly after birth, underscoring the value of this biomarker, according to Children’s research presented during the Pediatric Academic Societies 2019 Annual Meeting.

Tethered to an array of machines that keep their bodies nourished, warm and alive, newborns with health issues can’t speak. But Children’s research teams are tapping into what the machinery itself says, looking for insights into which vulnerable infants are most in need of earlier intervention.

“Heart rate variability – or the variation between heartbeats – is a sign of health. Our autonomic nervous system constantly sends signals to adjust our heart rate under normal conditions. We can measure heart rate variability non-invasively, providing a way to detect potential problems with the autonomic nervous system as a sensitive marker of health in critically ill newborns,” says An N. Massaro, M.D., co-Director of Research for the Division of Neonatology at Children’s National, and the study’s senior author. “We’re looking for validated markers of brain injury in babies with HIE, and our study helps to support heart rate variability as one such valuable physiological biomarker.”

In most newborns, the autonomic nervous system reliably and automatically receives information about the body and the outside world and, in response, controls essential functions like blood pressure, body temperature, how quickly the baby breathes and how rapidly the newborn’s heart beats. The sympathetic part stimulates body processes, while the parasympathetic part inhibits body processes. When the nervous system’s internal auto-pilot falters, babies can suffer.

The Children’s team enrolled infants with HIE in the prospective, observational study. (HIE is brain damage that occurs with full-term babies who experience insufficient blood and oxygen flow to the brain around the time they are born.) Fifteen percent had severe encephalopathy. Mean age of babies in the observational study was 38.9 weeks gestation. Their median Apgar score at five minutes was 3; the 0-9 Apgar range indicates how ready newborns are for the rigors of life outside the womb.

The team analyzed heart rate variability metrics for three time periods:

  • The first 24 to 27 hours of life
  • The first three hours after babies undergoing therapeutic cooling were rewarmed and
  • The first three hours after babies’ body temperature had returned to normal.

They correlated the relationship between heart rate variability for 68 infants during at least one of these time periods with the stress z-score from the NICU Network Neurobehavioral Scale. The scale is a standardized assessment of newborn’s neurobehavioral integrity. The stress summary score indicates a newborn’s overall stress response, and six test items specifically relate to autonomic function.

“Alpha exponent and root mean square in short timescales, root mean square in long timescales, as well as low and high frequency powers positively correlated with stress scores and, even after adjusting for covariates, remained independently associated at 24 hours,” says Allie Townsend, the study’s lead author.

Pediatric Academic Societies 2019 Annual Meeting presentation

  • “Heart rate variability (HRV) measures of autonomic nervous system (ANS) function relates to neonatal neurobehavioral manifestations of stress in newborn with hypoxic-ischemic encephalopathy (HIE).”
    • Monday, April 29, 2019, 5:45 p.m. (EST)

Allie Townsend, lead author; Rathinaswamy B. Govindan, Ph.D., staff scientist, Advanced Physiological Signals Processing Lab and co-author; Penny Glass, Ph.D., director, Child Development Program and co-author; Judy Brown, co-author; Tareq Al-Shargabi, M.S., co-author; Taeun Chang, M.D., director, Neonatal Neurology and Neonatal Neurocritical Care Program and co-author; Adré J. du Plessis, M.B.Ch.B., MPH, chief of the Division of Fetal and Transitional Medicine and co-author; An N. Massaro, M.D., co-Director of Research for the Division of Neonatology and senior author, all of Children’s National.

An-Massaro

Looking for ‘help’ signals in the blood of newborns with HIE

An Massaro

“This data support our hypothesis that a panel of biomarkers – not a one-time test for a single biomarker – is needed to adequately determine the risk and timing of brain injury for babies with HIE,” says An N. Massaro, M.D.

Measuring a number of biomarkers over time that are produced as the body responds to inflammation and injury may help to pinpoint newborns who are more vulnerable to suffering lasting brain injury due to disrupted oxygen delivery and blood flow, according to research presented during the Pediatric Academic Societies 2019 Annual Meeting.

Hypoxic-ischemic encephalopathy (HIE) happens when blood and oxygen flow are disrupted around the time of birth and is a serious birth complication for full-term infants. To lessen the chance of these newborns suffering permanent brain injury, affected infants undergo therapeutic cooling, which temporarily lowers their body temperatures.

“Several candidate blood biomarkers have been investigated in HIE but we still don’t have one in clinical use.  We need to understand how these markers change over time before we can use them to direct care in patients,” says An N. Massaro, M.D., co-director of the Neonatal Neurocritical Care Program at Children’s National and the study’s senior author. “The newborns’ bodies sent out different ‘help’ signals that we detected in their bloodstream, and the markers had strikingly different time courses. A panel of plasma biomarkers has the potential to help us identify infants most in need of additional interventions, and to help us understand the most optimal timing for those interventions.”

Past research has keyed in on inflammatory cytokines and Tau protein as potential biomarkers of brain injury for infants with HIE who are undergoing therapeutic cooling. The research team led by Children’s faculty wanted to gauge which time periods to measure such biomarkers circulating in newborns’ bloodstreams. They enrolled 85 infants with moderate or severe HIE and tapped unused blood specimens that had been collected as cooling began, as well as 12, 24, 72 and 96 hours later. The infants’ mean gestational age was 38.7 weeks, their mean birth weight was about 7 pounds (3.2 kilograms), and 19% had severe brain disease (encephalopathy).

Cytokines – chemicals like Interleukin (IL) 6, 8 and 10 that regulate how the body responds to infection, inflammation and trauma – peaked in the first 24 hours of cooling for most of the newborns. However, the highest measure of Tau protein for the majority of newborns was during or after the baby’s temperature was restored to normal.

“After adjusting for clinical severity of encephalopathy and five-minute Apgar scores, IL-6, IL-8 and IL-10 predicted adverse outcomes, like severe brain injury or death, as therapeutic hypothermia began. By contrast, Tau protein measurements predicted adverse outcomes during and after the infants were rewarmed,” Dr. Massaro says.

IL-6 and IL-8 proteins are pro-inflammatory cytokines while IL-10 is considered anti-inflammatory.  These chemicals are released as a part of the immune response to brain injury. Tau proteins are abundant in nerve cells and stabilize microtubules.

“This data support our hypothesis that a panel of biomarkers – not a one-time test for a single biomarker – is needed to adequately determine the risk and timing of brain injury for babies with HIE,” she adds.

Pediatric Academic Societies 2019 Annual Meeting presentation

  • “Serial plasma biomarkers of brain injury in infants with hypoxic ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH).”
    • Saturday, April 27, 2019, 6 p.m. (EST)

Meaghan McGowan, lead author; Alexandra C. O’Kane, co-author; Gilbert Vezina, M.D.,  director, Neuroradiology Program and co-author; Tae Chang, M.D., director, Neonatal Neurology Program and co-author; and An N. Massaro, M.D., co-director of the Neonatal Neurocritical Care Program and senior author; all of Children’s National; and co-author Allen Everett, of Johns Hopkins School of Medicine.

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.”

the cerebral blood flow (CBF) maps, corresponding anatomical image aligned to the CBF map, and the regions of interest examined

Tracking preemies’ blood flow to monitor brain maturation

Blood is the conduit through which our cells receive much of what they need to grow and thrive. The nutrients and oxygen that cells require are transported by this liquid messenger. Getting adequate blood flow is especially important during the rapid growth of gestation and early childhood – particularly for the brain, the weight of which roughly triples during the last 13 weeks of a typical pregnancy. Any disruption to blood flow during this time could dramatically affect the development of this critical organ.

Now, a new study by Children’s National Health System researchers finds that blood flow to key regions of very premature infants’ brains is altered, providing an early warning sign of disturbed brain maturation well before such injury is visible on conventional imaging. The prospective, observational study was published online Dec. 4, 2017 by The Journal of Pediatrics.

“During the third trimester of pregnancy, the fetal brain undergoes an unprecedented growth spurt. To power that growth, cerebral blood flow increases and delivers the extra oxygen and nutrients needed to nurture normal brain development,” says Catherine Limperopoulos, Ph.D., director of the Developing Brain Research Laboratory at Children’s National and senior author of the study. “In full-term pregnancies, these critical brain structures mature inside the protective womb where the fetus can hear the mother and her heartbeat, which stimulates additional brain maturation. For infants born preterm, however, this essential maturation process happens in settings often stripped of such stimuli.”

The challenge: How to capture what goes right or wrong in the developing brains of these very fragile newborns? The researchers relied on arterial spin labeling (ASL) magnetic resonance (MR) imaging, a noninvasive technique that labels the water portion of blood to map how blood flows through infants’ brains in order to describe which regions do or do not receive adequate blood supply. The imaging work can be done without a contrast agent since water from arterial blood itself illuminates the path traveled by cerebral blood.

“In our study, very preterm infants had greater absolute cortical cerebral blood flow compared with full-term infants. Within regions, however, the insula (a region critical to experiencing emotion), anterior cingulate cortex (a region involved in cognitive processes) and auditory cortex (a region involved in processing sound) for preterm infants received a significantly decreased volume of blood, compared with full-term infants. For preterm infants, parenchymal brain injury and the need for cardiac vasopressor support both were correlated with decreased regional CBF,” Limperopoulos adds.

The team studied 98 preterm infants who were born June 2012 to December 2015, were younger than 32 gestational weeks at birth and who weighed less than 1,500 grams. They matched those preemies by gestational age with 104 infants who had been carried to term. The brain MRIs were performed as the infants slept.

Blood flows where it is needed most with areas of the brain that are used more heavily commandeering more oxygen and nutrients. Thus, during brain development, CBF is a good indicator of functional brain maturation since brain areas that are the most metabolically active need more blood.

the cerebral blood flow (CBF) maps, corresponding anatomical image aligned to the CBF map, and the regions of interest examined

This figure represents the cerebral blood flow (CBF) maps, corresponding anatomical image aligned to the CBF map, and the regions of interest examined. The scale indicates the quantitative value of the CBF map and is expressed in mL/100g/min. The data are from a preterm infant scanned at term age without evidence of brain injury. The insula (see black arrows in panel ‘D’) may be particularly vulnerable to the added stresses of the preterm infant’s life outside the womb.
Credit: M. Bouyssi-Kobar, et al., The Journal of Pediatrics.

“The ongoing maturation of the newborn’s brain can be seen in the distribution pattern of cerebral blood flow, with the greatest volume of blood traveling to the brainstem and deep grey matter,” says Marine Bouyssi-Kobar, M.S., the study’s lead author. “Because of the sharp resolution provided by ASL-MR images, our study finds that in addition to the brainstem and deep grey matter, the insula and the areas of the brain responsible for sensory and motor functions are also among the most oxygenated regions. This underscores the critical importance of these brain regions in early brain development. In preterm infants, the insula may be particularly vulnerable to the added stresses of life outside the womb.”

Of note, compromised regional brain structures in adults are implicated in multiple neurodevelopmental disorders. “Altered development of the insula and anterior cingulate cortex in newborns may represent early warning signs of preterm infants at greater risk for long-term neurodevelopmental impairments,” Limperopoulos says.

Research reported in this post was supported by the Canadian Institutes of Health Research, MOP-81116; the SickKids Foundation, XG 06-069; and the National Institutes of Health under award number R01 HL116585-01.