WASHINGTON -- American scientists revealed exactly how the heart and blood vessels stay healthy.

A study, published on Thursday in the journal Cell, reported a protein called GPR68 that senses blood flow pressure, lending a new medical possibility for conditions, including ischemic stroke.

"It has been known for decades that blood vessels sense changes in blood flow rate, and this information is crucial in regulating blood vessel dilation and controlling vascular tone," said Ardem Patapoutian, a Scripps Research professor and senior author of the study. "The molecules involved within arteries to sense blood flow have remained unknown."

According to the researchers, flow-mediated dilation (FMD) is a non-invasive clinical test that informs doctors about the health of the vascular system and a compromised FMD is a precursor to a wide array of vascular diseases, such as hypertension and atherosclerosis.

Patapoutian's team started by designing a machine that uses turbulent movement of liquid to stand in for blood flow in blood vessels.

This machine uses 384 pistons that move the fluid up and down over a bed of cells, placed in 384 wells on a plate. This motion simulates how blood would put pressure on those cells.

The researchers put this machine to work, testing a series of cell lines, some of which had mutations that led to an over-expression of proteins potentially linked to pressure sensing.

The researchers then performed a screen, knocking down the expression of different candidate genes in each of the 384 wells, and tested if that gene is required for responding to the machine's turbulent pressure.

The tests pointed the researchers to GPR68, which the authors showed works as a sensor of mechanical stimulation.

Further experiments suggested that GPR68 is essential for FMD. "In a model organism, this protein is essential for sensing blood flow, and the proper functioning of the vascular system," said Patapoutian.

When arterioles cannot dilate properly, the body has fewer options for lowering blood pressure in people with hypertension or getting blood through clogged vessels in cases of atherosclerosis.
"Future work will explore the role of GPR68 in clinically relevant cardiovascular diseases," Patapoutian said. "We are also exploring the possibility of using small molecules to modulate the function of GPR68, as such molecules could be beneficial in the clinic." (Xinhua)