New Method More Effectively Delivers Drugs for Brain Injuries

The peptide CAQK could potentially prevent damage to brain cells and blood vessels.

A new technology has been created that delivers nanoparticles to injured areas of the brain, according to a study published by Nature Communications.

"We have found a peptide sequence of four amino acids, cysteine, alanine, glutamine, and lysine (CAQK), that recognizes injured brain tissue," said senior author of the study Erkki Ruoslahti, MD, PhD. "This peptide could be used to deliver treatments that limit the extent of damage."

Researchers believe this new technology could prevent secondary damage to brain cells and blood vessels.

"Current interventions for acute brain injury are aimed at stabilizing the patient by reducing intracranial pressure and maintaining blood flow, but there are no approved drugs to stop the cascade of events that cause secondary injury," said the study co-first author Aman Mann, PhD.

Experimental drugs in preclinical trials can stop damage such as inflammation, high levels of free radicals, over-excitation of neurons, and signaling that can cause cell death.

"Our goal was to find an alternative to directly injecting therapeutics into the brain, which is invasive and can add complications," Dr Ruoslahti said. "Using this peptide to deliver drugs means they could be administered intravenously, but still reach the site of injury in sufficient quantities to have an effect."

The CAQK peptide attaches to chondroitin sulfate proteoglycans, which are sugar decorated proteins that increase in number after brain injury, according to the study.

"Not only did we show that CAQK carries drug-sized molecules and nanoparticles to damaged areas in mouse models of acute brain injury, we also tested peptide binding to injured human brain samples and found the same selectivity," said Dr Mann.

The researchers are currently testing their findings in animal models of central nervous system injuries.

"This peptide could also be used to create tools to identify brain injuries, particularly mild ones, by attaching the peptide to materials that can be detected by medical imaging devices," Dr Ruoslahti concluded. "And, because the peptide can deliver nanoparticles that can be loaded with large molecules, it could enable enzyme or gene-silencing therapies."