Heart damage caused by a myocardial infarction is exacerbated by activation of a heart–brain–immune axis.Credit: Sevolod Zviryk/Science Photo Library
Researchers have proposed a rethink of the brain’s role in heart attacks, finding that crosstalk between the heart, the brain and the immune system damages the heart after a myocardial infarction in mice. The results, published in Cell on 27 January1, suggest that such events are not just diseases of the cardiovascular system.
In the study, scientists identify a brain–immune circuit that exacerbates cardiovascular pathology during a heart attack. They identified neurons in the vagus nerve that relay signals between the heart and the brain, which in turn activates immune and inflammatory responses and causes widespread damage to the heart. Blocking this pathway improved outcomes after a heart attack in mice, which could pave the way for developing new therapies.
“The heart does not exist in isolation. The nervous system talks to the heart, the immune system talks to the heart,“ says study co-author Vineet Augustine, a neuroscientist at the University of California, San Diego. The current work is a “step forward into putting all of these systems together and this approach can be applied to other diseases as well”, he adds.
“We have known for decades that the brain and nervous systems are critical components to [heart attack] pathogenesis, management and care,” says Cameron McAlpine who studies immune function in the cardiovascular and nervous systems at the Icahn School of Medicine at Mount Sinai in New York City. “It appears that this axis plays a critical role.“
Brain–heart axis
Heart attacks happen when blood flow to the heart muscle is blocked. They cause damage to the heart’s muscles, and trigger cellular and molecular changes across its tissues.
“The heart attack is exactly like an earthquake. You have an epicentre, which is a focal point and then it spreads out,” explains Augustine. “Once it starts spreading out, this is when a large chunk of the tissue dies.”
Earlier research has shown that the vagus nerve — a key pathway that connects the brain to many other organs — sends signals to the brain after a heart attack.
“All the regular functions of the heart are controlled by the nervous system,” says Kalyanam Shivkumar, a cardiologist at the University of California, Los Angeles.
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