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

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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.

Nobuyuki Ishibashi

R01 grant funds white matter protection study for congenital heart disease

Nobuyuki Ishibashi

Nobuyuki Ishibashi, M.D., is the principal investigator on a $3.2 million NIH R01 to study white matter growth and repair in utero for fetal brains affected by congenital heart disease.

Many of the neurological deficits seen in children with congenital heart disease (CHD) are related to abnormal white matter development early in life caused by reduced oxygen supply to the brain while in utero. Children with immature white matter at birth also commonly sustain additional white matter injuries following cardiac surgery.

The NIH recently awarded a prestigious R01 grant totaling more than $3.2 million to a collaborative project led by the Center for Neuroscience Research, the Sheikh Zayed Institute for Pediatric Surgical Innovation and the Children’s National Heart Institute at Children’s National Hospital as well as MedStar Washington Hospital Center.

The research, titled “White matter protection in the fetus with congenital heart disease,” looks specifically at whether providing a supplemental amount of the naturally occurring tetrahydrobiopterin (BH4) for pregnant women could rescue white matter development of fetuses with congenital heart disease whose brains aren’t receiving enough oxygen – or suffering from hypoxic-ischemic events.

Previous preclinical studies have shown that this lack of oxygen depletes the brain’s natural BH4 level, and the researchers hypothesize that BH4 levels play a critical role in the growth and development of white matter in the fetal brain by triggering key cellular/molecular processes. Specifically, the study will focus on three aims:

  1. Establish in a preclinical model the optimal protective regiment for women pregnant with a fetus who has CHD to receive BH4.
  2. Determine the appropriate approach to deliver BH4 to this population
  3. Leverage genetic tools and biochemical techniques in the laboratory to better understand where and how BH4 levels play a role in the growth (or lack thereof) of oligodendrocytes—the primary cells of white matter.

This laboratory-based work is the first step to determining if the neurodevelopment of babies born with CHD can be preserved or recovered by addressing key brain development that occurs before the baby is even born. Findings related to congenital heart disease may also translate to other populations where white matter development is affected by hypoxia-ischemia, including premature infants.

The project is led by principal investigator Nobuyuki Ishibashi, M.D., with co-investigators Vittorio Gallo, Ph.D., Joseph Scafidi, D.O., and Mary Donofrio, M.D. as well as colleagues at MedStar Washington Hospital Center.

Newborn baby laying in crib

Can cells collected from bone marrow stimulate generation of new neurons in babies with CHD?

Newborn baby laying in crib

The goal of the study will be to optimize brain development in babies with congenital heart disease (CHD) who sometimes demonstrate delay in the development of cognitive and motor skills.

An upcoming clinical trial at Children’s National Hospital will harness cardiopulmonary bypass as a delivery mechanism for a novel intervention designed to stimulate brain growth and repair in children who undergo cardiac surgery for congenital heart disease (CHD).

The NIH has awarded Children’s National $2.5 million to test the hypothesis that mesenchymal stromal cells (MSCs), which have been shown to possess regenerative properties and the ability to modulate immune responses in a variety of diseases, collected from allogeneic bone marrow, may promote regeneration of damaged neuronal and glial cells in the early postnatal brain. If successful, the trial will determine the safety of the proposed treatment in humans and set the stage for a Phase 2 efficacy trial of what could potentially be the first treatment for delays in brain development that happen before birth as a consequence of congenital heart disease. The study is a single-center collaboration between three Children’s National physician-researchers: Richard Jonas, M.D.Catherine Bollard, M.B.Ch.B., M.D. and Nobuyuki Ishibashi, M.D.

Dr. Jonas, chief of cardiac surgery at Children’s National, will outline the trial and its aims on Monday, November 18, 2019, at the American Heart Association’s Scientific Sessions 2019. Dr. Jonas was recently recognized by the Cardiac Neurodevelopmental Outcome Collaborative for his lifelong research of how cardiac surgery impacts brain growth and development in children with CHD.

Read more about the study: Researchers receive $2.5M grant to optimize brain development in babies with CHD.

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Regenerative Cell Therapy in Congenital Heart Disease – Protecting the Immature Brain
Presented by Richard Jonas, M.D.
AHA Scientific Sessions
Session CH.CVS.608 Congenital Heart Disease and Pediatric Cardiology Seminar: A Personalized Approach to Heart Disease in Children
9:50 a.m. to 10:05 a.m.
November 18, 2019