Adult fruit fly brain with the blood-brain barrier labeled in greenSHIRLEY ZHANG AND AMITA SEHGALGetting drugs past the blood-brain barrier (BBB) is notoriously difficult, but a study published today (March 8) in Cell offers a potential solution. Researchers found that the Drosophila BBB has a molecular clock that renders it more or less penetrable during certain hours of the day. Indeed, giving the flies a drug for treating seizures at night was more effective than during the day.
The authors “give mechanistic insight for how time-of-day difference in blood-brain barrier permeability comes to be,” says Robert Dallmann, a circadian biologist and pharmacologist at University of Warwick in the United Kingdom who did not participate in the study. “They even show that time of treatment really makes a difference.”
Researchers and clinicians have found that the timing of medical treatments—including vaccines and chemotherapy for brain cancer—can influence their efficacy, but it is still unclear how the circadian clock exerts these effects.
To investigate the permeability of the BBB, a team led by Amita Sehgal of the University of Pennsylvania injected fruit flies with fluorescent dye at four-hour timepoints throughout the day. They found that more of the dye made it into the insects’ brains ...
