in brief 2

Growing new neurons

For decades, conventional wisdom maintained that mammals are born with all the brain cells they’ll ever have. Now Emory scientists are helping turn this long-held truism on its head.

A research team led by Marla Luskin, professor of cell biology, recently showed that several regions of the adult rat brain acquired new neurons after a growth factor was injected deep into the cerebral cortex. The study, published in the September 1 issue of the Journal of Neuroscience, is the first to show new neurons in certain regions of the brain where they had never been found before. It suggests that the adult brain may be able to replace some neurons lost to injury or disease.

Although most neurons in the mammalian forebrain are formed prenatally, scientists have recently learned that certain areas of the adult brain, such as the hippocampus and the subventricular zone, can produce new neurons.

In Luskin’s study, scientists injected a growth factor called BDNF into the lateral ventricle of adult rat brains for two weeks. They waited another two weeks and then examined the brains for new cells. They found new neurons in several forebrain structures, including the parenchyma (gray matter) of the striatum, septum, thalamus, and hypothalamus—areas serving a multitude of cognitive and vital neurologic functions. Until this study, neurogenesis had not been shown in the thalamus and hypothalamus after birth and only in very limited numbers in the septum and striatum.

In previous studies, Luskin demonstrated that certain parts of the brain contain a unique population of neuronal progenitor cells. Elsewhere in the brain, neurons cannot divide. Luskin calls the results encouraging. “The number of new neurons we found in regions such as the striatum and hypothalamus suggests that the adult forebrain has a more profound capacity to produce new neurons than previously recognized,” she says.

The research was supported by the National Institutes of Health. (BACK TO TOP)

New Anthrax Antibiotics

Drugs within a new class of antibiotics called ketolides are effective in the laboratory against some strains of anthrax that are naturally resistant to erythromycin and other antibiotics, according the Emory infectious disease specialist Keith Klugman. Klugman tested ABT-773 (a ketolide under development) and other antimicrobials, including clarithromycin and ciprofloxacin, and found them effective against several human strains of anthrax and a selection of animal strains from southern Africa. The African strains are naturally resistant to erythromycin and are prevalent among African wild animals, including elephants. Human strains from Zimbabwe were from patients who had contracted anthrax by natural means some years ago. Ketolides are not yet approved by the FDA. The research was funded by Abbott Labs and done in collaboration with the National Laboratory Service of South Africa. (BACK TO TOP)