Featured Research

from universities, journals, and other organizations

Cause of fatal inflammation of the heart muscle identified

Date:
March 30, 2011
Source:
Helmholtz Association of German Research Centres
Summary:
Scientists have found out that inflammations of the heart muscle are caused by attacks of a specific type of immune cells. These immune cells attack the body's own tissue because during their maturation they did not have the chance to develop tolerance against a protein that is only found in the heart muscle.

Scientists of the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ), jointly with colleagues in the United States, have found out that inflammations of the heart muscle are caused by attacks of a specific type of immune cells. These immune cells attack the body's own tissue because during their maturation they did not have the chance to develop tolerance against a protein that is only found in the heart muscle.

An inflammation of the heart muscle, or myocarditis, frequently precedes a dangerous and often fatal heart enlargement. In many cases, the only promising treatment left is heart transplantation. For many years now, medical evidence has suggested that this dangerous inflammation is caused by autoimmune reactions, i.e., attacks by the body's own immune system.

However, it remained unclear whether it is antibodies or immune cells that damage the heart muscle tissue. It was also unknown which of the proteins in the cardiac muscle is the target of these fatal immune attacks. Jointly with colleagues from Harvard, the Dana Faber Cancer Institute and other U.S. research institutes, Professor Dr. Bruno Kyewski of the German Cancer Research Center (DKFZ) set out to investigate these questions.

The investigators studied mice that are often spontaneously affected by fatal myocarditis. Studying these animals, they discovered that α-MyHC, a type of heart muscle protein called myosin, is the target of autoaggressive immune cells. This protein is highly specific of the heart muscle and is not found in muscles of the skeleton.

Why is it that immune cells suddenly start attacking a harmless own protein? "This is the result of a lack of tolerance training," says DKFZ's Professor Dr. Bruno Kyewski. T cells, a specific type of immune cells, are prepared for their job during their early development in a special organ called thymus gland. Here they are presented a multitude of the body's own molecules which they are expected to recognize as known and harmless on their later patrols through the body. "We have now discovered that there is no α-MyHC in the thymus tissue of these mice. T cells therefore have no opportunity during their 'education' to meet this protein and thus develop specific tolerance."

The scientists also provided strong support for this hypothesis. They modified the mice's genetic material in such a way that their thymus gland became capable of producing α-MyHC. These animals were no longer affected by autoimmune myocarditis.

This hypothesis appears to be valid not only for mice, but also for humans. The investigators showed that human thymus tissue does not produce α-MyHC, either. Therefore, there are human T cells permanently circulating in the bloodstream which also have the potential of attacking the heart. "Normally, this causes no problems," said Bruno Kyewski. "But if the cardiac muscle gets damaged by a viral infection or an infarction and larger amounts of α-MyHC are released from the defective tissue, the fragile tolerance breaks down."

The results now published by the German-U.S. team are expected to contribute to developing more specific treatments against autoimmune myocarditis. So far, a common approach has been to attempt to suppress the production of antibodies in patients. "But now we know that we have to selectively block specific T cells to protect the heart in such cases," explained Kyewski.


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Journal Reference:

  1. HuiJuan Lv, Evis Havari, Sheena Pinto, Raju V.S.R.K. Gottumukkala, Lizbeth Cornivelli, Khadir Raddassi, Takashi Matsui, Anthony Rosenzweig, Roderick T. Bronson, Ross Smith, Anne L. Fletcher, Shannon J. Turley, Kai Wucherpfennig, Bruno Kyewski, Myra A. Lipes. Impaired thymic tolerance to α-myosin directs autoimmunity to the heart in mice and humans. Journal of Clinical Investigation, 2011; DOI: 10.1172/JCI44583

Cite This Page:

Helmholtz Association of German Research Centres. "Cause of fatal inflammation of the heart muscle identified." ScienceDaily. ScienceDaily, 30 March 2011. <www.sciencedaily.com/releases/2011/03/110329095656.htm>.
Helmholtz Association of German Research Centres. (2011, March 30). Cause of fatal inflammation of the heart muscle identified. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2011/03/110329095656.htm
Helmholtz Association of German Research Centres. "Cause of fatal inflammation of the heart muscle identified." ScienceDaily. www.sciencedaily.com/releases/2011/03/110329095656.htm (accessed September 30, 2014).

Share This



More Health & Medicine News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How 'Yes Means Yes' Defines Sexual Assault

How 'Yes Means Yes' Defines Sexual Assault

Newsy (Sep. 29, 2014) Aimed at reducing sexual assaults on college campuses, California has adopted a new law changing the standard of consent for sexual activity. Video provided by Newsy
Powered by NewsLook.com
Scientists May Have Found An Early Sign Of Pancreatic Cancer

Scientists May Have Found An Early Sign Of Pancreatic Cancer

Newsy (Sep. 29, 2014) Researchers looked at 1,500 blood samples and determined people who developed pancreatic cancer had more branched chain amino acids. Video provided by Newsy
Powered by NewsLook.com
Colo. Doctors See Cluster of Enterovirus Cases

Colo. Doctors See Cluster of Enterovirus Cases

AP (Sep. 29, 2014) Doctors at the Children's Hospital of Colorado say they have treated over 4,000 children with serious respiratory illnesses since August. Nine of the patients have shown distinct neurological symptoms, including limb weakness. (Sept. 29) Video provided by AP
Powered by NewsLook.com
Dr.'s Unsure of Cause of Fast-Spreading Virus

Dr.'s Unsure of Cause of Fast-Spreading Virus

AP (Sep. 29, 2014) Doctors at the Children's Hospital of Colorado say they have treated over 4,000 children with serious respiratory illnesses since August. Nine of the patients have shown distinct neurological symptoms, including limb weakness. (Sept. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins