NCTR Research Highlights

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Current Highlight from July 3, 2009

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In vivo Translational Biomarker for Nerve Cell Death

National Center for Toxicological Research (NCTR) scientists have completed experiments that demonstrate Positron Emission Tomography (PET) imaging, in combination with the annexin V molecular tracer, provide a minimally invasive approach for monitoring neuronal-cell death with enough sensitivity to resolve different brain areas. Ketamine, a dissociative anesthetic widely used in pediatric medicine, was injected into rat pups during the brain-growth spurt on postnatal-day 7. Annexin V, a compound used to label dying cells, was injected into rat pups on postnatal-day 35. Annexin V levels were much higher and remained longer in the animals exposed to ketamine suggesting that cell death from ketamine exposure continues much longer than previously thought. Concern over the use of ketamine anesthesia in pediatric medicine increased after animal experiments demonstrated increased neuronal-cell death when exposures occur during periods of rapid-brain development. Neuronal-cell death is accompanied by the exposure phosphatidylseine on the cell surface that is selectively labeled by the annexin V molecule. Experiments continue to evaluate the limits of sensitivity and validity of the method for clinical application. PET is commonly utilized in the clinic to trace biological processes related to disease and therapeutic efficacy. Results were presented at the 49th Annual Meeting of the Teratology Society, June 29-July 1, 2009.

For further information, contact Dr. William Slikker, Jr., Director, NCTR.