But the barrier can be disrupted by disease, stroke and multiple sclerosis, for example, and also is a big challenge for medicine, as it can be difficult or impossible to get therapeutic molecules through the barrier to treat neurological disorders.
Now, however, the blood-brain barrier may be poised to give up some of its secrets as researchers at the University of Wisconsin-Madison have created in the laboratory dish the cells that make up the brain's protective barrier. Writing in the June 24, 2012 edition of the journal Nature Biotechnology, the Wisconsin researchers describe transforming stem cells into endothelial cells with blood-brain barrier qualities.
Access to the specialized cells "has the potential to streamline drug discovery for neurological disease," says Eric Shusta, a UW-Madison professor of chemical and biological engineering and one of the senior authors of the new study. "You can look at tens of thousands of drug candidates and just ask the question if they have a chance to get into the brain. There is broad interest from the pharmaceutical industry."
The blood-brain barrier depends on the unique qualities of endothelial cells, the cells that make up the lining of blood vessels. In many parts of the body, the endothelial cells that line capillaries are spaced so that substances can pass through. But in the capillaries that lead to the brain, the endothelial cells nestle in tight formation, creating a semi-permeable barrier that allows some substances -- essential nutrients and metabolites -- access to the brain while keeping others -- pathogens and harmful chemicals -- locked out.
The cells described in the new Wisconsin study, which was led by Ethan S. Lippmann, now a postdoctoral fellow at the Wisconsin Institute for Discovery, and Samira M. Azarin, now a postdoctoral fellow at Northwestern University, exhibit both the active and passive regulatory qualities of those cells that make up the capillaries of the intact brain.
The research team coaxed both embryonic and induced pluripotent stem cells to form the endothelial cells of the blood-brain barrier. The use of induced cells, which can come from patients with specific neurological conditions, may be especially important for modeling disorders that compromise the blood-brain barrier. What's more, because the cells can be mass produced, they could be used to devise high-throughput screens for molecules that may have therapeutic value for neurological conditions or to identify existing drugs that may have neurotoxic qualities.
"The nice thing about deriving endothelial cells from induced pluripotent stem cells is that you can make disease-specific models of brain tissue that incorporate the blood-brain barrier," explains Sean Palecek, a UW-Madison professor of chemical and biological engineering and a senior author of the new report. "The cells you create will carry the genetic information of the condition you want to study."
The generation of the specialized blood-brain barrier endothelial cells, the Wisconsin researchers note, has never been done with stem cells. In addition to the potential applications to screen drugs and model pathologies of the blood-brain barrier, they may also provide a novel window for developmental biologists who are interested in how the barrier comes together and co-develops with the brain.
"Neurons develop at the same time as the endothelial cells," Shusta says, noting that, in development, the cells secrete chemical cues that help determine organ specificity.
"We don't know what all those factors are," Lippmann says. "But with this model, we can go back and look." Identifying all of the molecular factors at play as blank slate stem cells differentiate to become specialized endothelial cells could one day have clinical significance to treat stroke or tamp down the ability of brain tumors to recruit blood vessels needed to sustain cancer.The new study was supported by the U.S. National Institutes of Health and the U.S. National Science Foundation.
Terry Devitt | EurekAlert!
'Y' a protein unicorn might matter in glaucoma
23.10.2017 | Georgia Institute of Technology
Microfluidics probe 'cholesterol' of the oil industry
23.10.2017 | Rice University
Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
23.10.2017 | Event News
17.10.2017 | Event News
10.10.2017 | Event News
23.10.2017 | Life Sciences
23.10.2017 | Physics and Astronomy
23.10.2017 | Health and Medicine