Heart muscle inflammation: blood test could facilitate diagnosis!
Acute inflammation of the heart muscle (myocarditis) is often difficult to distinguish from a heart attack due to its symptoms. The laboratory values are also similar – as a result, patients often undergo a special X-ray examination of the heart (coronary angiography). However, no occlusions or signs of an infarction are found in acute myocarditis. Magnetic resonance imaging (MRI) would have to be performed to rule out myocarditis. However, this is not available everywhere and usually cannot take place in acute situations. A blood test should now make the diagnosis easier.
The reaction of the immune system is essential for the new findings: While myocarditis usually occurs as a result of a delayed infection and the immune system damages heart muscle cells through an overreaction, a heart attack tends to result in an inflammatory secondary reaction due to destroyed heart muscle cells – the immune system then plays an important role.
First studies show: heart muscle inflammation detected by blood test
Spanish scientists first studied the immune responses associated with myocardial infarction and myocarditis in mice and analyzed whether there might be detectable differences in the blood.
- Mimic myocarditis: Group 1 received an injection of a strong antigen (virus or bacteria) to elicit an immune response. It took about three weeks for this to happen.
- Imitation heart attack: Group 2 had a coronary artery (heart vessel) tied off to simulate an infarction. A malfunction was registered immediately as a result.
At the time of the heart attack or myocarditis, no differences in the blood of the two test groups could be detected.
A detailed examination of the Th17 cells – certain helper cells that are supposed to support the immune system in the fight against foreign bodies – led to the discovery of a biomarker that clearly separated the two test groups.
When comparing both diseases, the microRNA miR-721 was found, which, according to the researchers, occurs when the immune system attacks in the event of heart muscle inflammation. In the following, a similar microRNA was searched for by examining the human genome. The scientists found different sequences.
Initial results show that one of these sequences can also provide an indication of how to differentiate between the two diseases. In further studies, the feature is to be examined as part of the diagnosis and follow-up of heart muscle inflammation.