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Healthy Heart Needs Coordination of 2 Proteins

Healthy Heart Needs Coordination of 2 Proteins

Friday, 19 April, 2019 - 05:30
A new US study suggests that two proteins that work together may be responsible for a healthy heart. (AFP)
Cairo - Hazem Bader
A new US study suggests that two proteins that work together may be responsible for a healthy heart. Heart disease may develop when the signaling between the two proteins is out of balance.

In their study conducted on mice, scientists at the National Institutes of Health identified these proteins as stress hormone receptors known as the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR).

They also assessed heart health without one of the receptors, then, without both of them. Stress induces adrenal glands to make a hormone called cortisol, which is involved in the fight-or-flight response and binds to the two receptors in different tissues of the body to reduce inflammation.

If the body lacks these two receptors, common risk factors for heart disease may arise, such as increased cholesterol and glucose in the blood and high blood pressure. The study was published Tuesday in the Science Signaling journal.

Lead author, Robert Oakley, first identified this problem in the 1990s when he was a graduate student at the University of North Carolina. Soon after the discovery, other scientists determined that people with above average amounts of these proteins had greater risk of heart disease.

Based on this finding, Oakley wanted to know the perfect condition of these proteins.

For this purpose, he tested a mouse strain without heart GR. These animals spontaneously developed enlarged hearts leading to heart failure and death. When the team produced a mouse strain missing cardiac MR, the animals' hearts functioned normally.

Oakley then wondered what would happen if both receptors were missing from heart tissue, so he made another mouse strain that lacked GR and MR. They guessed that these double-knockout mice would have the same or worse heart problems as the mice without GR. However, surprisingly, the hearts function normally, but they are slightly enlarged compared to the hearts with no MR.

"As the human body contains both proteins, it's not reasonable to make molecules that only work on one receptor, as they used to do in the past," Dr. Oakley told Asharq Al-Awsat.

"The best approach is to make a drug that works on both receptors simultaneously. It could help patients with heart disease and prevent subsequent heart diseases," he noted.

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