Over the course of a lifetime, the heart pumps some 250 million liters of blood through the body. In the order to do this, the muscle fibers of the heart have to be extremely durable. The research group headed by Dr. Wolfgang Rottbauer, vice chair of the Department of Medicine III at Heidelberg University Hospital (Chairman: Prof. Dr. H. A. Katus), has discovered a protein that is responsible for the stability of the smallest muscular unit, the sarcomere.
In cooperation with other researchers within the National Genome Research Network (NGFN) which is funded by the German Federal Ministery of Education and Research, especially Prof. Dr. H. Schunkert from the University of Lübeck and Prof. Dr. M. Stoll from the University of Münster, they proved that mutations of this protein are the cause of a new type of heart failure. The results have been published in the November issue of Nature Medicine.
Primary heart muscle disease with decreased cardiac pump function leading to enlargement of the heart chambers (dilated cardiomyopathy) is one of the most frequent causes of chronic heart failure. Six new cases per 100,000 people occur each year; 20 percent of these cases are genetic. The heart disease weakens cardiac cells and the heart can no longer pump efficiently which leads to dilation of the cardiac chambers.
Muscle activity takes place in the smallest unit of muscle fiber, the sarcomere. In the presence of an appropriate stimulus, actin and myosin filaments interact and contract the muscle. These movable elements are anchored in what are known as Z-disks. With every heartbeat, enormous forces act on the Z-disks.
Torn Z disks weaken the heart
“In our studies of zebrafish, we discovered a protein that is needed to stabilize the Z-disk. If this protein (nexilin) is mutated, the movable muscle elements are no longer anchored firmly enough. The muscles then lose strength and the heart is weakened,” explains Dr. Tillman Dahme, resident and co-author of the study. The researchers examined the genetic material of affected patients and verified a mutated Z-disk protein in 9 of 1000 participants. They showed that in these patients, the defective nexilin was the major cause of heart disease. “The nexilin dilated cardiomyopathy allowed us for the first time to describe a new form of heart muscle dilatation and define the mechanism causing it, namely destabilization of the Z-disk,” says Dahme.
The studies also showed that the extent of the damage to the Z-disk is directly related to the workload. This insight has an influence on clinical therapy. “Patients with a nexilin mutation might benefit from early treatment with medications that reduce cardiac stress. This could lower the mechanical stress on the Z-disks and prevent progressive damage to the heart,” said Dr. Rottbauer.
Nexilin mutations destabilize cardiac Z-disks and lead to dilated cardiomyopathy. David Hassel, Tillman Dahme, Jeanette Erdmann, Benjamin Meder, Andreas Huge, Monika Stoll, Steffen Just, Alexander Hess, Philipp Ehlermann, Dieter Weichenhan, Matthias Grimmler, Henrike Liptau, Roland Hetzer, Vera Regitz-Zagrosek, Christine Fischer, Peter Nürnberg, Heribert Schunkert, Hugo A Katus & Wolfgang Rottbauer, Nature Medicine 15, 1281 - 1288 (2009), published online 1 Nov 2009, DOI 10.1038/nm.2037Contact person:
Requests by journalists:Dr. Annette Tuffs
Dr. Wolfgang Rottbauer | EurekAlert!
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Life Sciences
21.08.2017 | Information Technology
18.08.2017 | Life Sciences