Tag Archive for: gamma-aminobutyric acid

Representative OFF and DIFF spectra

GABA and glutamate in the preterm neonatal brain

Preterm and sick newborns are at high risk of brain injury that can lead to cognitive delays and behavioral disorders including autism and ADHD. Gamma-aminobutyric acid (GABA) and glutamate system disruptions may underlie these neonatal brain injuries and hence it is important to describe their normative profile in the developing neonatal brain.

In a study led by Sudeepta Basu, M.D., neonatologist at Children’s National Hospital and Assistant Professor of Pediatrics at George Washington University School of Medicine and Health Sciences, specialized GABA editing spectroscopy (MEGA-PRESS) was acquired on a 3Tesla MRI scanner. Although MEGA-PRESS has been used in older subjects, there are challenges in the newborn population that have limited investigations with only a few institutions worldwide. Under the leadership of Catherine Limperopoulos, Ph.D., in the Developing Brain Institute (DBI) at Children’s National, a team of scientists (in particular, Dr. Subechhya Pradhan) have diligently overcome the technical challenges to enable use of this cutting-edge technology for research at the institute.

With this unique capability, Dr. Basu’s team prospectively enrolled 58 healthy newborns to describe the normal GABA and glutamate concentrations in different regions of the developing brain. In a recent article published in the American Journal of Neuroradiology, Dr. Basu reports that GABA and glutamate concentrations were highest in the cerebellum, slightly lower in the basal ganglia, but significantly lower in the frontal lobe.

“Our ability to reliably describe the normal metabolic-neurotransmitter milieu of the developing newborn brain is the first step in filling a critical gap in knowledge,” says Dr. Basu. “We hope to identify early bio-markers of brain injury of cognitive delays and autism and ADHD risk which remains a major challenge until clinical symptoms manifest later in childhood.”

Under the direction of Dr. Limperopoulos, advanced multi-modal high precision MRI protocols have been developed for use in research studies at Children’s National that allows the scientists to identify subtle signs of delayed growth and development of the newborn brain. With the optimization of MEGA-PRESS for newborns, Children’s National is one of a few institutions worldwide capable of investigating the newborn brain neurotransmitters in future research studies.

Read the full article in American Journal of Neuroradiology.

Representative OFF and DIFF spectra

Representative OFF and DIFF spectra.

Sudeepta Basu

GABA concentration in pre-term brain increases with gestational age

Sudeepta Basu

“A more complete understanding of the diagnostic and prognostic importance of GABA and glutamate in the preterm brain will help us to direct treatment strategies for the most vulnerable preterm infants at risk of brain injury,” says Sudeepta K. Basu, M.D.

The major neurotransmitters gamma-aminobutyric acid (GABA) and glutamate are pivotal to fetal and newborn brain development and influence evolution of brain injury and repair following preterm birth. Magnetic resonance spectroscopy (MRS) enables in vivo measurement of brain metabolites. However, GABA and glutamate are found in the developing brain in low concentrations, and their weak signal can be swamped by the stronger signal of more dominant metabolites.

A Children’s research team reports findings from a pilot study utilizing an innovative technique of MRS to reliably measure in vivo GABA in the developing preterm brain. The groundbreaking research done by the team that includes Principal Investigator Sudeepta K. Basu, M.D., neonatology attending at Children’s National Health System, is very unique and original since there are no existing data of in vivo GABA concentrations in the developing cerebellum. Under the mentorship of Catherine Limperopoulos, Ph.D., director of Children’s Developing Brain Research Laboratory, the team of multi-disciplinary specialists is pursuing cutting-edge technologies in advanced MRI neuroimaging to explore brain development and injury in preterm infants.

The research, presented at the Eastern Society for Pediatric Research (ESPR) annual meeting by Dr. Basu, was honored with the “2018 Meritorious Poster Award.” The research titled “Distinct temporal trends of GABA and glutamate in the cerebellum and frontal cortex of preterm infants” reports, for the first time, positive temporal trends in the specific regions of the developing brain intricately involved in cognitive and motor functions. This work lays the foundation for developing novel ways to diagnose, monitor and investigative brain protective therapies for vulnerable prematurely born infants.

The Children’s team performed non-sedated MRS in 44 preterm infants whose mean gestational age at birth was 26.5 weeks, placing voxels at the middle of the cerebellum and the right frontal cortex. GABA and GIx (glutamate combined with glutamine) were positively correlated with post-menstrual age in the frontal cortex, but not the cerebellum.  At the ESPR meeting, the team also presented for the first time that caffeine, a neuroprotective agent in preemies, leads to increased in vivo GABA concentration in the developing frontal cortex.

“Open questions include whether these findings reflect varying paces of maturation and vulnerability to injury among specific regions of the brain. Also, the relationship between clinical factors and medication exposure and changes in the concentration of these neurotransmitters may guide brain protective therapies in future,” Dr. Basu says. “A more complete understanding of the diagnostic and prognostic importance of GABA and glutamate in the preterm brain will help us to direct treatment strategies for the most vulnerable preterm infants at risk of brain injury.”

Children’s senior fellows from Division of Neonatology made four platform presentations during the ESPR conference:

  • “Caffeine increases GABA/Cr ratio in frontal cortex of preterm infants on spectroscopy.” Aditi Gupta; Sudeepta K. Basu, M.D.; Mariam Said, M.D.; Subechhya Pradhan, Linda White; Kushal Kapse; Jonathan Murnick, M.D., Ph.D.; Taeun Chang, M.D.; and Catherine Limperopoulos, Ph.D.
  • “Impact of early nutrition on microstructural brain development in VLBW Infants.” Katherine M. Ottolini, Nickie Andescavage, M.D.; Kushal Kapse; and Catherine Limperopoulos, Ph.D.
  • “Direct measurement of neonatal cardiac output utilizing the CO status monitor.” Simranjeet S. Sran, Mariam Said, M.D.; and Khodayar Rais-Bahrami, M.D.
  • “Cerebro-cerebellar diaschisis in preterm infants following unilateral cerebral parenchymal injury.” Huma Mirza, Yao Wu, Kushal Kapse, Jonathan Murnick, M.D., Ph.D.; Taeun Chang, M.D.; and Catherine Limperopoulos, Ph.D.