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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.”