Injecting nanoparticles in the blood curbed brain swelling in mice – Science News

Injecting a swarm of nanoparticlesinto the blood of someone who has suffered a brain injury may one day help tolimit the damage if experimental results in mice can be translated to humans. In mice, these nanoparticlesseemed to reduce dangerous swelling by distracting immune cells from rushing to aninjured brain.

The results, describedonline January 10 in the Annals ofNeurology, hint that the inflammation-fighting nanoparticles might somedaymake powerful medicine, says John Kessler, a neurologist at NorthwesternMedicine in Chicago. All the data we have now suggest that theyre going to besafe, and theyre likely to work for people, Kessler says. But we dont knowthat yet.

After an injury, tissueoften swells as immune cells flock to the damage. Swelling of the brain can be dangerousbecause the brain is contained within the skull and theres no place to go, Kesslersays. The resulting pressure can be deadly.

But nanoparticles might serveas an immune-cell distraction, the results in mice suggest.

Headlines and summaries of the latest Science News articles, delivered to your inbox

Two to three hours after ahead injury, mice received injections of tiny biodegradable particles made ofan FDA-approved polymer the same sort thats used in some dissolving sutures. Instead of rushing towardthe brain, a certain type of immune cell called monocytes began turning theirsights on these invaders. These monocytes engulfed the nanoparticles, and thecells and their cargo got packed off to the spleen for elimination, theresearchers found. Because these nanoparticles are quickly taken out ofcirculation, the researchers injected the mice again one and two days later, inan effort to ease inflammation that might crop back up in the days after theinjury.

Mice that received the nanoparticles fared better after their brain injuriesthan mice that didnt get the nanoparticles. Ten weeks after the injury, thedamaged spots themselves were about half as big as the spots in mice thatdidnt receive the treatment, suggesting the damage was stalled in the micethat got nanoparticles.

Other tests showed that bothbrain swelling and scarring were less severe in mice that had receivednanoparticles. Mices vision cells performed better in response to light. And behaviorimproved, too. Mice were able to walk better across a ladder if they had receivedthe nanoparticle decoys. The scope of the animals improvements was a muchbigger effect than you actually expected or hoped for, Kessler says.

Other potential nanoparticle therapies rely on tethering drugs or other cargo to thenanoparticles themselves (SN: 3/7/19).But in this study, the nanoparticles were bare. Thats different from what wetypically think of as a nanoparticle treatment, says Forrest Kievit, abiomedical engineer at the University of NebraskaLincoln. That simplicity might make the manufacturingof these particles more straightforward than other, more complicatednanoparticles, a benefit for potential clinical trials.

Kievit cautions, however,that there are many differences between mice and human brain injuries: the typeand severity of the injuries and the timelines for recovery are different, forinstance. And the ways that the brain suffers after a hard hit involves morethan just a harmful immune response. Toxic substances can accumulate and spreadto unaffected areas, for instance.

Still, Kessler is optimisticthat these nanoparticles hold promise not just for treating brain injuries, butalso for a wide range of ailments that involve a potentially damaging immuneresponse. In 2014, researchers found that nanoparticlesdistracted monocytes from causing inflammation in other circumstances in mice. Similar nanoparticles seemed toimprove mices heart health after undergoing a blockage that mimics a heartattack. Nanoparticles also seemed to ease signs of inflammatory bowel disease,and boosted survival of mice infected with West Nile virus.

There are few ways to treat traumaticbrain injuries, Kessler says. Theres nothing thats really been able to makea dent in this disease. Thats why it would be so exciting if it really works.

See the rest here:
Injecting nanoparticles in the blood curbed brain swelling in mice - Science News