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!
Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society
127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Power and Electrical Engineering
18.01.2017 | Materials Sciences
18.01.2017 | Life Sciences