Blood–Brain Barrier: How It Works--Definition, Structure, Function

DN Bureau

Researching the wall separating the circulatory system from the neurological system has been highly difficult or limited in its use of models. Read further on Dynamite News:

Representational Image
Representational Image

Zurich: Researching the wall separating the circulatory system from the neurological system has been highly difficult or limited in its use of models. In order to properly investigate potential new treatments for brain tumours, researchers have created a more realistic model.

A postdoc at ETH Zurich's Bio Engineering Laboratory Mario Modena has done extensive research on it. 

If he were to explain his research on the blood-brain barrier to an 11-year-old, he would say, "This wall is important because it prevents the bad guys from getting into the brain." The blood-brain barrier is the wall that shields our central nervous system from harmful substances in the bloodstream. He claims that holes might emerge in the wall if the brain is injured or ill.

Sometimes, such holes can actually be useful, for example, for supplying the brain with urgently needed medicine. "So what we are trying to understand is how to maintain this wall, break through it and repair it again."

This wall is also important from a medical perspective because many diseases of the central nervous system are linked to an injury to the blood-brain barrier. To discover how this barrier works, scientists often conduct experiments on live animals. In addition to such experiments being relatively expensive, animal cells may provide only part of the picture of what is going on in the human body. Moreover, there are some critics, who question the basic validity of animal testing. An alternative is to base experiments on human cells that have been cultivated in the laboratory.

There are also dynamic in-vitro models that simulate flow conditions in the body, but the catch here is that the pumps they require make the experimental setup rather complicated. Alongside all these challenges, there is the problem of measurement: it is all but impossible to take high-resolution images of structural changes to the blood-brain barrier in real-time while also measuring the barrier's electrical resistance, both of which reflect barrier compactness and tightness.

If each of these challenges were a bird, Modena's platform would be the proverbial stone that kills them all. Working under Andreas Hierlemann, Modena and his colleagues spent three and a half years developing the open-microfluidic 3D blood-brain barrier model.

To mimic the way fluid flows in the body, the researchers realized the microfluidic platform with fluid reservoirs at both ends on a kind of seesaw. Gravity then triggered the flow, which -- in turn -- generated shear force on the cells. Hierlemann explains the benefit of this setup: "Since we are not using any pumps, we can experiment with multiple model systems simultaneously, for instance in an incubator, without increasing the setup complexity."

In a study, published recently in the journal Advanced Science, the researchers presented and tested their new in vitro blood-brain barrier model. They subjected the barrier to oxygen-glucose deprivation, as happens when someone is having a stroke. "These experiments allowed us to trigger rapid changes in the barrier and demonstrate the platform's potential," Modena says. (with ANI inputs)

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