MAR 22, 2017 8:57 PM PDT

Immune Cell Unexpectedly Drives Transition to Heart Disease

WRITTEN BY: Kara Marker

A human heart recuperating from inflammation, a condition called myocarditis, can take one of two paths: a healthy return to normal function or a dangerous transition to another condition called inflammatory dilated cardiomyopathy (DCMi). In the past scientists have been bewildered as to why some people recover and others do not, but a recent study’s findings shows that the presence of a certain type of immune cell may be the explanation.

A modified electron microscopy image of eosinophils infiltrating a heart. Eosinophils (pink) can be seen between heart muscle cells (blue) and fibroblasts (turquoise). Eosinophils and other immune cells (orange) exit the blood vessels (green) and infiltrate the heart during myocarditis.

"Our studies show that the presence of eosinophils in the heart makes mice more likely to get DCMi following myocarditis,” explained first author of a new study published in The Journal of Experimental Medicine, Nicola Diny. “And if there are a lot of eosinophils, the mice develop even more severe heart failure.”

Eosinophils are white blood cells with specific “instructions” from the immune system to fight parasites, and they are also linked to allergies, autoimmune disease, and some types of cancer. Myocarditis is under-studied and probably under-diagnosed as a result. A myocarditis diagnosis requires a biopsy to be taken directly from a person’s heart tissue. On the rare occasions when it is diagnosed, the specific type of myocarditis is identified by the most prevalent type of immune cell present in the heart.

Following coronary artery disease and arterial hypertension, dilated cardiomyopathy is a top cause of heart failure. DCMi is one of many types of dilated cardiomyopathy, all of which are characterized by a dysfunctional heart muscle.

Connections have already been made between high levels of eosinophils and the development of heart disease, but the present study, led by senior author Daniela Cihakova, MD, PhD, is the first to examine eosinophil activity through the lens of heart inflammation. The new research, Cihakova said, “provided more details about how these immune system cells may lead to deterioration of heart muscle function in mice in a way that lets us draw some parallels to human disease processes.”

To definitively confirm the role of eosinophils in the progression of myocarditis to DCMi, Cihakova designed a classic study: a comparison between normal mice and mice genetically altered to lack eosinophils. After both groups were induced to have myocarditis, Cihakova looked for inflammatory patterns.

There were similar levels of initial, acute inflammation in the heart in both groups of mice. However, as more time passed, the difference in the long-term effects between the two groups of mice grew remarkably distinct; normal mice developed heart failure and mice lacking eosinophils did not.

"The take-home message is that inflammation severity doesn't necessarily determine long-term disease progression,” Cihakova explained. “But specific infiltrating cell types - eosinophils, in this case - do.”

Sources: American Academy of Allergy, Asthma, and Immunology, European Society of Cardiology, Johns Hopkins Medicine

About the Author
I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
APR 06, 2022
Cardiology
Are Leadless Pacemakers the Future?
APR 06, 2022
Are Leadless Pacemakers the Future?
The human heart rate is under the influence of various hormonal and neural control mechanisms. Normally, conduction of a ...
APR 19, 2022
Cardiology
Daily Coffee May Improve Longevity and Heart Health
APR 19, 2022
Daily Coffee May Improve Longevity and Heart Health
Good news for coffee fans!
JUN 12, 2022
Plants & Animals
Vegan Diet Rich in Legumes Helps with Weight Loss
JUN 12, 2022
Vegan Diet Rich in Legumes Helps with Weight Loss
New research conducted by the Physicians Committee for Responsible Medicine suggests that a vegan diet offers a range of ...
JUN 26, 2022
Drug Discovery & Development
Vitamin Supplements are a 'Waste of Money' for Healthy Americans
JUN 26, 2022
Vitamin Supplements are a 'Waste of Money' for Healthy Americans
The US Preventive Services Task Force (USPSTF) recommends against using beta carotene or vitamin E supplements to preven ...
SEP 14, 2022
Health & Medicine
Researchers Suggest Updating Alcohol Warning Labels
SEP 14, 2022
Researchers Suggest Updating Alcohol Warning Labels
Current warning labels that appear on alcohol products in the US are outdated, vague, and not helpful to people who want ...
SEP 20, 2022
Cardiology
Increased Duration, Frequency, and Intensity of Exercise Lowers Heart Risks
SEP 20, 2022
Increased Duration, Frequency, and Intensity of Exercise Lowers Heart Risks
More moderate-intensity exercise per week may drastically lower heart failure risk.
Loading Comments...