How aircraft noise damages blood vessels

Larissa Melville completed her traineeship in the editorial team of . After studying biology at Ludwig Maximilians University and the Technical University of Munich, she first got to know digital media online at Focus and then decided to learn medical journalism from scratch.

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Aircraft noise is more than just annoying: in the long term, it promotes cardiovascular diseases such as high blood pressure, heart attacks or strokes. The reason for this are aggressive molecules that form under the influence of aircraft noise and that damage the wall of blood vessels.

As early as 2013, a study showed that simulated night flight noise in humans increases the stress hormone adrenaline in the blood and blood pressure, reduces the quality of sleep and can trigger a dysfunction of the blood vessels, the endothelial dysfunction. This plays a crucial role in the development of arteriosclerosis.

Among other things, the narrowing and widening of the vessels no longer works properly, and their permeability for liquids can no longer be properly adjusted. Both are central control mechanisms that regulate blood pressure.

Four days of aircraft noise

In experiments with mice, the cardiologist Thomas Münzel from Johannes Gutenberg University Mainz and his colleagues have now for the first time deciphered the mechanisms that are responsible for the connection between noise and heart disease. To do this, they exposed the animals to either aircraft noise or normal ambient noise (“white noise”) for four days. The mean noise level was the same.

The result: After just one day, the aircraft noise drove up the stress hormone levels and blood pressure of the rodents. In addition, the vascular function of the animals deteriorated.

Free radicals disrupt the vascular function

The researchers found that the main reason for the changes was an increased formation of free radicals. These are aggressive molecules that damage cells and cause them to age prematurely. Apparently the aircraft noise stimulated the production of two enzymes that form free radicals: NADPH oxidase and NOS.

Studies showing that the radical scavenger vitamin C could protect the endothelial function of aircraft noise suggest that oxidative stress could play a central role in noise-related vascular damage.

Altered gene activity

In addition, the researchers analyzed the activity of the genes that are responsible for the state of tension, the structure of the vessel wall and cell death in the vessels. In fact, aircraft noise influenced precisely these genes: some of them were overactive, others less active than before.

And the scientists made another interesting discovery: In contrast to aircraft noise, the same noise level with ambient noise did not have a negative effect on the vessels. Noise is not the same as noise - depending on the source, the body reacts to it to a greater or lesser extent.

Prevent noise damage to the heart

"We have to expect that noise increases the effect of other cardiovascular risk factors and thus the process of vascular calcification," the researchers write. For the first time, it will now also be possible to test to what extent drugs that affect the heart and circulation can prevent damage to blood vessels caused by aircraft noise.

Sources:

Münzel T. et al .: Effects of noise on vascular function, oxidative stress, and inflammation: mechanistic insight from studies in mice. European Heart Journal.DOI: https://doi.org/10.1093/eurheartj/ehx081

Press release from Johannes Gutenberg University Mainz on February 17th, 2017: Cardiologists from Mainz decipher mechanisms that are responsible for vascular damage as a result of aircraft noise

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