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illustration of the amygdaloid body

Research reveals physiological sex differences in medial amygdala neurons

illustration of the amygdaloid body

The medial amygdala (MeA) is a region of the brain that modulates innate social and non-social behaviors in several mammals, including humans.

The medial amygdala (MeA) is a region of the brain that modulates innate social and non-social behaviors in several mammals, including humans. Notedly sexually dimorphic, MeA neurons exhibit well-documented sex differences in anatomy, morphology and molecular characteristics. Recently, a pioneer study published in eNeuro from the Children’s National Hospital Center for Neuroscience Research has unveiled new information regarding physiological sex differences in MeA neurons, which, until now, has remained a missing piece in understanding how the MeA codes differently in males and females.

Previous research from Children’s National has shown that two subpopulations of MeA inhibitory output neurons descended from Dbx1 and Foxp2 transcription factors display different responses to innate olfactory cues and in a sex-specific manner. The newest study examines whether these transcription factor defined neurons also possess sex-specific biophysical signatures. The scientists posit that understanding how sex and lineage impact upstream differences at the neuronal level can help illuminate how the MeA processes information and codes for sex-specific behavioral differences.

Using whole-cell patch clamp recording and stepwise current injection, the researchers were able to analyze the intrinsic electrophysiological profiles of the two subclasses of MeA neurons in males and females in a pre-clinical model. Data revealed that the spike frequency of Dbx1-lineage and Foxp2-lineage neurons differed by lineage, sex and stimulus strength. Dbx1-lineage neurons in females discharged more spikes than those in males during high-amplitude current injection, while Foxp2-lineage neurons in females discharged more spikes than those in males during low-amplitude current injection. Across lineage, researchers observed that Dbx1-lineage neurons discharged more spikes than Foxp2-lineage neurons in females, but only at the highest amplitude stimulus, while Dbx1-lineage neurons spiked more than Foxp2-lineage neurons in males during low rather than high-amplitude current injection.

Different spiking patterns are generally indicative of different intrinsic cell properties. However, this study found that the intrinsic properties of the cell – such as membrane potential, resistance, and rheobase – were the same at rest across sex and lineage. The only significant difference was found in capacitance, an electrical measurement that roughly corresponds with cell size. Additionally, the study found that spike frequency adaptation correlated with neuronal lineage and sex, with males having a higher adaptation factor than females and Foxp2-lineage neurons displaying a higher adaptation factor than Dbx1-lineage neurons. In tandem, these results indicated that changes in the intrinsic properties were taking place during stimulation.

The researchers then used waveform phase-plots to visualize phases of the different action potentials and contrived an innovative new method of analyzing these quantitatively instead of solely qualitatively. This allowed them to know that broadly, ion channels that work with repolarization are likely different, and prompted them to focus on the family of ion channels that are known to modify the repolarization phase. From 62 candidate ion channels, the researchers chose 10 to investigate. Experiments ultimately revealed that only one ion channel was found to exhibit statistically significant sex differences in the Foxp2 population. This result indicated that molecular expression of these ion channels are likely driving differences in the physiology of the cells which may be the basis of behavioral expression. Future research topics include how and when sex hormones shape MeA neuronal firing properties and how this relates to network function.

“This is a small piece of contribution to the overall understanding of how the brain as a biological machine codes for different outputs,” says first author Heidi Y. Matos, Ph.D.

By showing sex differences in neural function, this research represents progress in understanding the biological underpinnings of a host of developmental disorders, particularly those diagnosed in different proportions between males and females. Autism spectrum disorders, for example, often have symptoms that manifest through social interaction, and understanding these disorders requires a better understanding of normal MeA physiology.

“In order to get to the why, we have to get to the how of that circuit,” says Dr. Matos.

Just as the brain harnesses the collective power of a diverse range of neurons, the Center for Neuroscience harnesses the aggregate talent of a diverse group of neuroscientists to produce innovative work. This study in particular champions diversity in the sciences, with more than half of the authors coming from underrepresented minorities, including Dr. Matos.

“I think this work is a shining example of the tremendous contributions that are made by neuroscientists from all backgrounds,” says principal investigator Joshua G. Corbin, Ph.D.

“Sex Differences in Biophysical Signatures across Molecularly Defined Medial Amygdala Neuronal Subpopulations” was published in eNeuro. Additional authors include David Hernandez-Pineda, Claire M. Charpentier, Allison Rusk and Kevin S. Jones, Ph.D.

doctors operating

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

doctors operating

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

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

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

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

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

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

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

Vittorio Gallo and Mark Batshaw

Children’s National Research Institute releases annual report

Vittorio Gallo and Marc Batshaw

Children’s National Research Institute directors Vittorio Gallo, Ph.D., and Mark Batshaw, M.D.

The Children’s National Research Institute recently released its 2019-2020 academic annual report, titled 150 Years Stronger Through Discovery and Care to mark the hospital’s 150th birthday. Not only does the annual report give an overview of the institute’s research and education efforts, but it also gives a peek in to how the institute has mobilized to address the coronavirus pandemic.

“Our inaugural research program in 1947 began with a budget of less than $10,000 for the study of polio — a pressing health problem for Washington’s children at the time and a pandemic that many of us remember from our own childhoods,” says Vittorio Gallo, Ph.D., chief research officer at Children’s National Hospital and scientific director at Children’s National Research Institute. “Today, our research portfolio has grown to more than $75 million, and our 314 research faculty and their staff are dedicated to finding answers to many of the health challenges in childhood.”

Highlights from the Children’s National Research Institute annual report

  • In 2018, Children’s National began construction of its new Research & Innovation Campus (CNRIC) on 12 acres of land transferred by the U.S. Army as part of the decommissioning of the former Walter Reed Army Medical Center campus. In 2020, construction on the CNRIC will be complete, and in 2012, the Children’s National Research Institute will begin to transition to the campus.
  • In late 2019, a team of scientists led by Eric Vilain, M.D., Ph.D., director of the Center for Genetic Medicine Research, traveled to the Democratic Republic of Congo to collect samples from 60 individuals that will form the basis of a new reference genome data set. The researchers hope their project will generate better reference genome data for diverse populations, starting with those of Central African descent.
  • A gift of $5.7 million received by the Center for Translational Research’s director, Lisa Guay-Woodford, M.D., will reinforce close collaboration between research and clinical care to improve the care and treatment of children with polycystic kidney disease and other inherited renal disorders.
  • The Center for Neuroscience Research’s integration into the infrastructure of Children’s National Hospital has created a unique set of opportunities for scientists and clinicians to work together on pressing problems in children’s health.
  • Children’s National and the National Institute of Allergy and Infectious Diseases are tackling pediatric research across three main areas of mutual interest: primary immune deficiencies, food allergies and post-Lyme disease syndrome. Their shared goal is to conduct clinical and translational research that improves what we know about those conditions and how we care for children who have them.
  • An immunotherapy trial has allowed a little boy to be a kid again. In the two years since he received cellular immunotherapy, Matthew has shown no signs of a returning tumor — the longest span of time he’s been tumor-free since age 3.
  • In the past 6 years, the 104 device projects that came through the National Capital Consortium for Pediatric Device Innovation accelerator program raised $148,680,256 in follow-on funding.
  • Even though he’s watched more than 500 aspiring physicians pass through the Children’s National pediatric residency program, program director Dewesh Agrawal, M.D., still gets teary at every graduation.

Understanding and treating the novel coronavirus (COVID-19)

In a short period of time, Children’s National Research Institute has mobilized its scientists to address COVID-19, focusing on understanding the virus and advancing solutions to ameliorate the impact today and for future generations. Children’s National Research Institute Director Mark Batshaw, M.D., highlighted some of these efforts in the annual report:

  • Eric Vilain, M.D., Ph.D., director of the Center for Genetic Medicine Research, is looking at whether or not the microbiome of bacteria in the human nasal tract acts as a defensive shield against COVID-19.
  • Catherine Bollard, M.D., MBChB, director of the Center for Cancer and Immunology Research, and her team are seeing if they can “train” T cells to attack the invading coronavirus.
  • Sarah Mulkey, M.D., Ph.D., an investigator in the Center for Neuroscience Research and the Fetal Medicine Institute, is studying the effects of, and possible interventions for, coronavirus on the developing brain.

You can view the entire Children’s National Research Institute academic annual report online.

Children's National employs 45 pediatric neurologists and 6 pediatric neurosurgeons.

2019 at a glance: Neuroscience at Children’s National

The Children’s National Division of Neurology and Neurosurgery is consistently recognized by U.S. News & World Report as one of the top neurology programs in the nation.
Billie Lou Short and Kurt Newman at Research and Education Week

Research and Education Week honors innovative science

Billie Lou Short and Kurt Newman at Research and Education Week

Billie Lou Short, M.D., received the Ninth Annual Mentorship Award in Clinical Science.

People joke that Billie Lou Short, M.D., chief of Children’s Division of Neonatology, invented extracorporeal membrane oxygenation, known as ECMO for short. While Dr. Short did not invent ECMO, under her leadership Children’s National was the first pediatric hospital to use it. And over decades Children’s staff have perfected its use to save the lives of tiny, vulnerable newborns by temporarily taking over for their struggling hearts and lungs. For two consecutive years, Children’s neonatal intensive care unit has been named the nation’s No. 1 for newborns by U.S. News & World Report. “Despite all of these accomplishments, Dr. Short’s best legacy is what she has done as a mentor to countless trainees, nurses and faculty she’s touched during their careers. She touches every type of clinical staff member who has come through our neonatal intensive care unit,” says An Massaro, M.D., director of residency research.

For these achievements, Dr. Short received the Ninth Annual Mentorship Award in Clinical Science.

Anna Penn, M.D., Ph.D., has provided new insights into the central role that the placental hormone allopregnanolone plays in orderly fetal brain development, and her research team has created novel experimental models that mimic some of the brain injuries often seen in very preterm babies – an essential step that informs future neuroprotective strategies. Dr. Penn, a clinical neonatologist and developmental neuroscientist, “has been a primary adviser for 40 mentees throughout their careers and embodies Children’s core values of Compassion, Commitment and Connection,” says Claire-Marie Vacher, Ph.D.

For these achievements, Dr. Penn was selected to receive the Ninth Annual Mentorship Award in Basic and Translational Science.

The mentorship awards for Drs. Short and Penn were among dozens of honors given in conjunction with “Frontiers in Innovation,” the Ninth Annual Research and Education Week (REW) at Children’s National. In addition to seven keynote lectures, more than 350 posters were submitted from researchers – from high-school students to full-time faculty – about basic and translational science, clinical research, community-based research, education, training and quality improvement; five poster presenters were showcased via Facebook Live events hosted by Children’s Hospital Foundation.

Two faculty members won twice: Vicki Freedenberg, Ph.D., APRN, for research about mindfulness-based stress reduction and Adeline (Wei Li) Koay, MBBS, MSc, for research related to HIV. So many women at every stage of their research careers took to the stage to accept honors that Naomi L.C. Luban, M.D., Vice Chair of Academic Affairs, quipped that “this day is power to women.”

Here are the 2019 REW award winners:

2019 Elda Y. Arce Teaching Scholars Award
Barbara Jantausch, M.D.
Lowell Frank, M.D.

Suzanne Feetham, Ph.D., FAA, Nursing Research Support Award
Vicki Freedenberg, Ph.D., APRN, for “Psychosocial and biological effects of mindfulness-based stress reduction intervention in adolescents with CHD/CIEDs: a randomized control trial”
Renee’ Roberts Turner for “Peak and nadir experiences of mid-level nurse leaders”

2019-2020 Global Health Initiative Exploration in Global Health Awards
Nathalie Quion, M.D., for “Latino youth and families need assessment,” conducted in Washington
Sonia Voleti for “Handheld ultrasound machine task shifting,” conducted in Micronesia
Tania Ahluwalia, M.D., for “Simulation curriculum for emergency medicine,” conducted in India
Yvonne Yui for “Designated resuscitation teams in NICUs,” conducted in Ghana
Xiaoyan Song, Ph.D., MBBS, MSc, “Prevention of hospital-onset infections in PICUs,” conducted in China

Ninth Annual Research and Education Week Poster Session Awards

Basic and Translational Science
Faculty:
Adeline (Wei Li) Koay, MBBS, MSc, for “Differences in the gut microbiome of HIV-infected versus HIV-exposed, uninfected infants”
Faculty: Hayk Barseghyan, Ph.D., for “Composite de novo Armenian human genome assembly and haplotyping via optical mapping and ultra-long read sequencing”
Staff: Damon K. McCullough, BS, for “Brain slicer: 3D-printed tissue processing tool for pediatric neuroscience research”
Staff: Antonio R. Porras, Ph.D., for “Integrated deep-learning method for genetic syndrome screening using facial photographs”
Post docs/fellows/residents: Lung Lau, M.D., for “A novel, sprayable and bio-absorbable sealant for wound dressings”
Post docs/fellows/residents:
Kelsey F. Sugrue, Ph.D., for “HECTD1 is required for growth of the myocardium secondary to placental insufficiency”
Graduate students:
Erin R. Bonner, BA, for “Comprehensive mutation profiling of pediatric diffuse midline gliomas using liquid biopsy”
High school/undergraduate students: Ali Sarhan for “Parental somato-gonadal mosaic genetic variants are a source of recurrent risk for de novo disorders and parental health concerns: a systematic review of the literature and meta-analysis”

Clinical Research
Faculty:
Amy Hont, M.D., for “Ex vivo expanded multi-tumor antigen specific T-cells for the treatment of solid tumors”
Faculty: Lauren McLaughlin, M.D., for “EBV/LMP-specific T-cells maintain remissions of T- and B-cell EBV lymphomas after allogeneic bone marrow transplantation”

Staff: Iman A. Abdikarim, BA, for “Timing of allergenic food introduction among African American and Caucasian children with food allergy in the FORWARD study”
Staff: Gelina M. Sani, BS, for “Quantifying hematopoietic stem cells towards in utero gene therapy for treatment of sickle cell disease in fetal cord blood”
Post docs/fellows/residents: Amy H. Jones, M.D., for “To trach or not trach: exploration of parental conflict, regret and impacts on quality of life in tracheostomy decision-making”
Graduate students: Alyssa Dewyer, BS, for “Telemedicine support of cardiac care in Northern Uganda: leveraging hand-held echocardiography and task-shifting”
Graduate students: Natalie Pudalov, BA, “Cortical thickness asymmetries in MRI-abnormal pediatric epilepsy patients: a potential metric for surgery outcome”
High school/undergraduate students:
Kia Yoshinaga for “Time to rhythm detection during pediatric cardiac arrest in a pediatric emergency department”

Community-Based Research
Faculty:
Adeline (Wei Li) Koay, MBBS, MSc, for “Recent trends in the prevention of mother-to-child transmission (PMTCT) of HIV in the Washington, D.C., metropolitan area”
Staff: Gia M. Badolato, MPH, for “STI screening in an urban ED based on chief complaint”
Post docs/fellows/residents:
Christina P. Ho, M.D., for “Pediatric urinary tract infection resistance patterns in the Washington, D.C., metropolitan area”
Graduate students:
Noushine Sadeghi, BS, “Racial/ethnic disparities in receipt of sexual health services among adolescent females”

Education, Training and Program Development
Faculty:
Cara Lichtenstein, M.D., MPH, for “Using a community bus trip to increase knowledge of health disparities”
Staff:
Iana Y. Clarence, MPH, for “TEACHing residents to address child poverty: an innovative multimodal curriculum”
Post docs/fellows/residents:
Johanna Kaufman, M.D., for “Inpatient consultation in pediatrics: a learning tool to improve communication”
High school/undergraduate students:
Brett E. Pearson for “Analysis of unanticipated problems in CNMC human subjects research studies and implications for process improvement”

Quality and Performance Improvement
Faculty:
Vicki Freedenberg, Ph.D., APRN, for “Implementing a mindfulness-based stress reduction curriculum in a congenital heart disease program”
Staff:
Caleb Griffith, MPH, for “Assessing the sustainability of point-of-care HIV screening of adolescents in pediatric emergency departments”
Post docs/fellows/residents:
Rebecca S. Zee, M.D., Ph.D., for “Implementation of the Accelerated Care of Torsion (ACT) pathway: a quality improvement initiative for testicular torsion”
Graduate students:
Alysia Wiener, BS, for “Latency period in image-guided needle bone biopsy in children: a single center experience”

View images from the REW2019 award ceremony.

Roger Packer

Roger J. Packer, M.D. presents keynote address for BRAIN 2019

Roger Packer

2019 Otto Lien Da Wong visiting professor in neuro-oncology at BRAIN 2019, Roger J. Packer, M.D. presented the keynote address.

 

More than 400 neurologists, neurosurgeons, pathologists, pediatricians, clinical and basic scientists gathered in Hong Kong for Brain 2019, a conjoint congress of the 3rd Asian Central Nervous System Germ Cell Tumour Conference (CNSGCT), the 9th Interim Meeting of the International Chinese Federation of Neurosurgical Sciences (ICFNS) and the 16th Asia Pacific Multidisciplinary Meeting for Nervous System Diseases (BRAIN) which is also jointly organized by The Chinese University of Hong Kong. This three-day convention discussed advances in pediatric neuro-oncology and neuro-rehabilitation.

Invited as the 2019 Otto Lien Da Wong (OLDW) visiting professor in neuro-oncology, Roger J. Packer, M.D., senior vice president for the Center of Neuroscience and Behavioral Medicine and director at the Gilbert Neurofibromatosis and Brain Tumor Institutes, presented a keynote address titled “Advances in Pediatric Brain Tumors.” Established in 2009, the purpose of the visiting professorship is to advance surgical knowledge and techniques in neuro-oncology between Hong Kong and major medical centers around the world. Dr. Packer was selected from an international field of acclaimed academic surgeons and scholars in the field of neuro-oncology. Two additional presentations included “Pediatric Brain Tumors in Molecular Era: Germ Cell Tumors” as an invited guest of the BRAIN conference and a presentation on “Treatment of Medulloblastoma and PNET” as a session presented by the ICFNS.

In addition to his presentations, Dr. Packer will participate in surgical teaching and scholastic exchange with local surgeons, surgical trainees and medical students.

Nobuyuki Ishibashi

Cortical dysmaturation in congenital heart disease

Nobuyuki Ishibashi

On Jan. 4, 2019, Nobuyuki Ishibashi, M.D., the director of the Cardiac Surgery Research Laboratory and an investigator with the Center for Neuroscience Research at Children’s National Health System, published a review in Trends in Neurosciences about the mechanisms of cortical dysmaturation, or disturbances in cortical development, that can occur in children born with congenital heart disease (CHD). By understanding the early-life impact and relationship between cardiac abnormalities and cortical neuronal development, Dr. Ishibashi and the study authors hope to influence strategies for neonatal neuroprotection, mitigating the risk for developmental delays among CHD patients.

Dr. Ishibashi answers questions about this review and CHD-neurodevelopmental research:

  1. Tell us more about your research. Why did you choose to study these interactions in this patient population?

My research focuses on studying how CHD and neonatal cardiac surgery affect the rapidly-developing brain. Many children with CHD, particularly the most complex anomalies, suffer from important behavioral anomalies and neurodevelopmental delays after cardiac surgery. As a surgeon scientist, I want to optimize treatment strategy and develop a new standard of care that will reduce neurodevelopmental impairment in our patients.

  1. How does this study fit into your larger body of work? What are a few take-home messages from this paper?

Our team and other laboratories have recently identified a persistent perinatal neurogenesis that targets the frontal cortex – the brain area responsible for higher-order cognitive functions. The main message from this article is that further understanding of the cellular and molecular mechanisms underlying cortical development and dysmaturation will likely help to identify novel strategies to treat and improve outcomes in our patients suffering from intellectual and behavioral disabilities.

  1. What do you want pediatricians and researchers to know about this study? Why is it important right now?

Although the hospital mortality risk is greatly reduced, children with complex CHD frequently display subsequent neurological disabilities affecting intellectual function, memory, executive function, speech and language, gross and fine motor skills and visuospatial functions. In addition to the impact of the neurological morbidity on the patients themselves, the toll on families and society is immense. Therefore it is crucial to determine the causes of altered brain maturation in CHD.

  1. How do you envision this research influencing future studies and pediatric health outcomes? As a researcher, how will you proceed?

In this article we placed special emphasis on the need for well-designed preclinical studies to define disturbances in cortical neurogenesis due to perinatal brain injury. I believe that further study of the impact of hypoxemia on brain development is of broad relevance — not just for children with congenital heart disease, but for other populations where intellectual and behavioral dysfunctions are a source of chronic morbidity, such as survivors of premature birth.

  1. What discoveries do you envision being at the forefront of this field?

One of the important questions is: During which developmental period, prenatal or postnatal, is the brain most sensitive to developmental and behavioral disabilities associated with hypoxemia? Future experimental models will help us study key effects of congenital cortical development anomalies on brain development in children with CHD.

  1. What impact could this research make? What’s the most striking finding and how do you think it will influence the field?

Although cortical neurogenesis at fetal and adult stages has been widely studied, the development of the human frontal cortex during the perinatal period has only recently received greater attention as a result of new identification of ongoing postnatal neurogenesis in the region responsible for important intellectual and behavioral functions. Children’s National is very excited with the discoveries because it has opened new opportunities that may lead to regeneration and repair of the dysmature cortex. If researchers identify ways to restore endogenous neurogenic abilities after birth, the risk of neurodevelopment disabilities and limitations could be greatly reduced.

  1. Is there anything else you would like to add that we didn’t ask you about? What excites you about this research?

In this article we highlight an urgent need to create a truly translational area of research in CHD-induced brain injury through further exploration and integration of preclinical models. I’m very excited about the highly productive partnerships we developed within the Center for Neuroscience Research at Children’s National, led by an internationally-renowned developmental neuroscientist, Vittorio Gallo, Ph.D., who is a co-senior author of this article. Because of our collaboration, my team has successfully utilized sophisticated and cutting-edge neuroscience techniques to study brain development in children born with CHD. To determine the causes of altered brain maturation in congenital heart disease and ultimately improve neurological function, we believe that a strong unity between cardiovascular and neuroscience research must be established.

Additional study authors include Camille Leonetti, Ph.D., a postdoctoral research fellow with the Center for Neuroscience Research and Children’s National Heart Institute, and Stephen Back, M.D., Ph.D., a professor of pediatrics at Oregon Health and Science University.

The research was supported by multiple grants and awards from the National Institutes of Health, inclusive of the National Heart Lung and Blood Institute (RO1HL139712), the National Institute of Neurological Disorders and Stroke (1RO1NS054044, R37NS045737, R37NS109478), the National Institute on Aging (1RO1AG031892-01) and the National Institute of Child Health and Human Development (U54HD090257).

Additional support for this review was awarded by the American Heart Association (17GRNT33370058) and the District of Columbia Intellectual and Developmental Disabilities Research Center, which is supported through the Eunice Kennedy Shriver National Institute of Child Health and Human Development program grant 1U54HD090257.

Vittorio Gallo

Perinatal brain injury headlines American Society for Neurochemistry

Vittorio Gallo

Dr. Gallo’s research could have major implications for overcoming the common behavioral and developmental challenges associated with premature birth.

Children’s National Chief Research Officer Vittorio Gallo, Ph.D., recently had the honor of presenting a presidential lecture at the 48th Annual Meeting of the American Society for Neurochemistry (ASN). The lecture focused on his lifelong investigations of the cellular and molecular mechanisms of white matter development and injury, including myelin and glial cells – which are involved in the brain’s response to injury.

Specifically, he outlined the underlying diffuse white matter injury observed in his lab’s pre-clinical model of perinatal hypoxia, and presented new, non-invasive interventions that promote functional recovery and attenuate developmental delay after perinatal injury in the model. Diffuse white matter injuries are the most frequently observed pattern of brain injury in contemporary cohorts of premature infants. Illuminating methods that might stimulate growth and repair of such injuries shows promise for potential noninvasive strategies that might mitigate the long-term behavioral abnormalities and developmental delay associated with premature birth.

Dr. Gallo’s work in developmental neuroscience has been seminal in deepening understanding of cerebral palsy and multiple sclerosis. During his tenure as center director, he transformed the Center for Neuroscience Research into one of the nation’s premier programs.

ASN gathers nearly 400 delegates from the neurochemistry sector each year, including bench and clinical scientists, principal investigators, graduate students and postdoctoral fellows all actively involved in research from North America and around the world.

Joseph Scafidi

Developing brains are impacted, but can recover, from molecularly targeted cancer drugs

Joseph Scafidi

“The plasticity of the developing brain does make it susceptible to treatments that alter its pathways,” says Joseph Scafidi, D. O., M.S. “Thankfully, that same plasticity means we have an opportunity to mitigate the damage from necessary and lifesaving treatments by providing the right support after the treatment is over.”

One of the latest developments in oncology treatments is the advancement of molecularly targeted therapeutic agents. These drugs can be used to specifically target and impact the signaling pathways that encourage tumor growth, and are also becoming a common go to for ophthalmologists to treat retinopathy of prematurity in neonates.

But in the developing brain of a child or adolescent, these pathways are also crucial to the growth and development of the brain and central nervous system.

“These drugs have been tested in vitro, or in tumor cells, or even in adult studies for efficacy, but there was no data on what happens when these pathways are inhibited during periods when their activation is also playing a key role in the development of cognitive and behavioral skills, as is the case in a growing child,” says Joseph Scafidi, D. O., M.S., a neuroscientist and pediatric neurologist who specializes in neonatology at Children’s National Health System.

As it turns out, when the drugs successfully inhibit tumor growth by suppressing receptors, they can also significantly impact the function of immature brains, specifically changing cognitive and behavioral functions that are associated with white matter and hippocampal development.

The results appeared in Cancer Research, and are the first to demonstrate the vulnerability of the developing brain when this class of drugs is administered. The pre-clinical study looked at the unique impacts of drugs including gefitinib (Iressa), sunitib malate (Sutent) and rapamycin (Sirolimus) that target specific pathways responsible for the rapid growth and development that occurs throughout childhood.

The agents alter signaling pathways in the developing brain, including decreasing the number of oligodendrocytes, which alters white matter growth. Additionally, the agents also impact the function of specific cells within the hippocampus related to learning and memory. When younger preclinical subjects were treated, impacts of exposure were more significant. Tests on the youngest pre-clinical subjects showed significantly diminished capacity to complete cognitive and behavioral tasks and somewhat older, e.g. adolescent, subjects showed somewhat fewer deficits. Adult subjects saw little or no deficit.

“The impacts on cognitive and behavioral function for the developing brain, though significant, are still less detrimental than the widespread impacts of chemotherapy on that young brain,” Dr. Scafidi notes. “Pediatric oncologists, neuro-oncologists and ophthalmologists should be aware of the potential impacts of using these molecularly targeted drugs in children, but should still consider them as a treatment option when necessary.”

The effects are reversible

Researchers also found measurable improvements in these impaired cognitive and behavioral functions when rehabilitation strategies such as environmental stimulation, cognitive therapy and physical activity were applied after drug exposure.

“The plasticity of the developing brain does make it susceptible to treatments that alter its pathways,” says Dr. Scafidi. “Thankfully, that same plasticity means we have an opportunity to mitigate the damage from necessary and lifesaving treatments by providing the right support after the treatment is over.”

Many major pediatric oncology centers, including the Center for Cancer and Blood Disorders at Children’s National, already incorporate rehabilitation strategies such as cognitive therapy and increased physical activity to help pediatric patients return to normal life following treatment. The results from this study suggest that these activities after treatment for pediatric brain tumors may play a vital role in improving recovery of brain cognitive and behavioral function in the pediatric population.

This research was funded by grants to Dr. Scafidi from the National Brain Tumor Society, Childhood Brain Tumor Foundation and the National Institutes of Health.

Nathan Smith

Sounding the alarm on fluorescent calcium dyes

“This study serves as a warning to other neuroscientists,” says Nathan A. Smith, Ph.D., a new principal investigator in the Center for Neuroscience Research at Children’s National Health System and first author of the study.

Scientists using chemical based fluorescent dyes to study the calcium dynamics of the cells within the central nervous system suspected that something external was disrupting normal cell function in their studies.

Neuroscientists at the University of Rochester Medical Center and Children’s National Health System have confirmed their suspicions by capturing data that shows, for the first time, how these fluorescent calcium dyes are causing cell damage when loaded over an extended period of time.  Their findings appeared in Science Signaling.

“This study serves as a warning to other neuroscientists,” says Nathan A. Smith, Ph.D., a new principal investigator in the Center for Neuroscience Research at Children’s National Health System and first author of the study. “As many of my colleagues have noted, we’ve known that something was going on, but now, we have evidence that the longer these dyes stay in cells, or the longer time it takes to load them into cells, the more problems we see with normal cell function.”

The study comparatively analyzed the effects of chemical and genetically encoded calcium ion indicators on cellular functions, which had not been previously performed. The outcomes showed that all of the fluorescent calcium dyes, including Fluo-4, Rhod-2, and FURA-2, had negative consequences for a number of cellular functions. For example, the dyes inhibited the sodium potassium pump (Na,K-ATPase), a membrane protein essential for many cellular membrane functions including the exchange between intracellular sodium ions (Na+) and extracellular potassium ions (K+). Inhibiting the Na,K-ATPase process results in the buildup of K+ ions in the synapses, leading to errant neural firing that has been linked to a number of disorders, including epilepsy. Additional observed impacts of exposure to the dyes included reduced cell viability, decreased glucose uptake, increased lactate release and cell swelling.

“Now, our field needs to take a step back and reevaluate findings that may have been influenced by these chemical trackers, to make sure that our observations were driven by our intended manipulations and not this additional factor,” Dr. Smith continues.

Non-chemical alternatives

Tracking calcium ions and their dynamics within the central nervous system through fluorescent calcium indicators is the primary method of measuring glial activity and glial interactions with other cell types. Unlike neurons, glial cells are electrically non-excitable; therefore electrical-based recording methods used to measure neuronal activity are ineffective.

In recent years, neuroscientists have developed additional methods to track calcium ions: genetically encoded calcium indicators (GECIs), which have grown in use since 2008. These GECIs have evolved over the years to have higher signal to noise ratios, target specific cell types and sub-compartments, and remain stable over time.*

Dr. Smith’s lab uses GECIs exclusively to monitor the calcium dynamics of glial brain cells called astrocytes as well as their interactions with other cells such as neurons. His work now seeks to understand how those interactions influence neural networks and how they operate differently in neurodevelopmental disorders, including attention-deficit hyperactivity disorder (ADHD), epilepsy and others.

“Our field has continued using these traditional calcium indicator dyes in labs because they are familiar and affordable,” Dr. Smith notes. “Our findings are a clear call to action that it’s time to revisit some of those approaches in favor of new technology.”