Scientists at Yale University School of Medicine have discovered a new way to reduce heart damage caused by immune cells during heart attacks—by switching these cells into a “night mode.”
The research could lead to better treatments that protect the heart without weakening the body’s ability to fight infections.
The study was published in the Journal of Experimental Medicine. It focuses on immune cells called neutrophils. These cells are among the first to arrive at the scene of injury or infection.
They help fight off germs and begin the healing process. But sometimes, they do more harm than good. Their powerful chemicals can destroy not only germs and damaged tissue but also healthy cells nearby.
Neutrophils have an internal clock. They are more active during the day and less aggressive at night. This natural rhythm might help explain why heart attacks that happen early in the morning are often more damaging than those that happen at night.
When a heart attack occurs, neutrophils rush to the damaged heart muscle. In their active daytime mode, they surround the injured area and can cause extra harm to nearby healthy tissue.
Professor Andrés Hidalgo and his team at Yale wanted to find a way to control this destructive activity without stopping neutrophils from doing their job. In earlier research, they showed that mice with neutrophils that don’t follow this daily cycle still fight infections well but don’t cause as much tissue damage.
In the new study, the researchers tested a drug called ATI2341 in mice. This drug turns on a receptor protein on the surface of neutrophils and shifts them into their calmer, night-time state—even during the day.
They found that mice treated with ATI2341 had smaller areas of heart damage after a heart attack. The drug helped protect the heart muscle and improved heart function over the days and weeks that followed. The neutrophils in treated mice stayed closer to the center of the damaged tissue, where they were less likely to harm surrounding healthy heart cells.
What’s more, ATI2341 didn’t weaken the immune system. Mice that received the drug were still able to fight off bacterial and fungal infections just as well as untreated mice. This is important, because many treatments that block neutrophils end up reducing the body’s ability to fight infection or heal properly.
The results suggest that shifting neutrophils into a nighttime-like mode can reduce damage after a heart attack and still keep the immune system strong. According to Professor Hidalgo, this method offers a safer way to control inflammation compared to older treatments that stop neutrophils altogether.
This research could lead to new drugs that protect people from the harmful effects of heart attacks while avoiding the usual side effects of immune-suppressing medications. More studies will be needed before this treatment can be used in humans, but the early results are promising.
If you care about heart health, please read studies about top 10 foods for a healthy heart, and how to eat right for heart rhythm disorders.
For more health information, please see recent studies about how to eat your way to cleaner arteries, and salt and heart health: does less really mean more?
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