Turns out red blood cells can protect the heart during an attack
A study has shown that red blood cells can activate a cardioprotective mechanism when oxygen levels are low, such as during a heart attack.The researchers found that red blood cells have an innate ability to trigger a mechanism that protects the heart from damage when it lacks oxygen, such as during a heart attack. It turned out the effect was more pronounced in people who followed a diet high in nitrates. These are found in green leafy vegetables such as spinach and arugula.
Red blood cells (red blood cells) carry oxygen from the lungs to the rest of the body. However, some studies have shown that they also respond to low oxygen levels by triggering the release of nitric oxide (NO). It causes vasodilation or dilation of blood vessels.
NO is a natural vasodilator. It is thought to have an effect that protects the heart from damage during hypoxia. Now, researchers from the Karolinska Institute in Sweden have studied the red blood cell signaling pathway to see if the cells have an innate ability to signal to protect the heart when oxygen levels are low.
The researchers first tested in mice whether red blood cells exposed to hypoxia release a cardioprotective mediator. It turned out that hypoxic red blood cells improved heart function and reduced the amount of tissue damage caused by low oxygen levels.
Having established that hypoxia releases a cardioprotective factor from red blood cells, the researchers sought to elucidate the nature of this relationship. It was found that erythrocytes carry soluble guanylate cyclase (rGC), which forms guanosine-3,5'-cyclic monophosphate (cyclic HMF or cGMP). This messenger molecule modulates many of the body's responses, including vasodilation.
To determine the involvement of rGCs, the scientists exposed red blood cells taken from mice that had been genetically modified not to produce guanylate cyclase to hypoxia and injected them into models of myocardial infarction. The red blood cells failed to protect the hearts from damage.
The scientists also found that administration of phosphodiesterase 5 (PDE5), a cGMP inhibitor, eliminated the cardioprotective effect. Another experiment in mice showed that nitrate "enriched" red blood cells with nitrates improved cardiac recovery compared to red blood cells without them.
Scientists plan to develop drugs that activate red blood cells' protective signaling mechanism during hypoxia.
The study is published in the Journal of Clinical Investigation.