During a heart attack, irreparable damage is done to the heart muscle as a result of defective circulation. The feared consequence is what is known as ventricular tachycardias and the ventricular fibrillation that results from that. In this case, the hollow muscle's contraction is not coordinated and contracts at a high pulse rate. The frequency can reach more than 300 beats per minute. This condition is life-threatening because the blood cannot be pumped effectively via the blood circulation.
By implanting embryonic myocardial cells, this risk can apparently be drastically reduced, at least in mice. These are the results of scientists from the universities of Bonn, Cornell and Pittsburgh, published in the journal 'Nature'. The scientists treated mice after a heart attack with these cells and then tried to cause ventricular tachycardias by means of electrical stimulation. Only with slightly over one third of the mice did this arrhythmia occur just as rarely as with thoroughly healthy rodents. By contrast, with untreated mice after a heart attack this ratio was almost 100 per cent.
A few thousand cells are sufficient
Replacing the dead heart tissue with new muscle cells is not a completely new idea. Up to now, the doctors focused especially on the reconstruction of the muscular function. After all, several hundred million muscle cells perish during a heart attack. The result is often heart failure, which can also be fatal. 'This weakness of the cardiac muscle cannot be resolved with spare tissue, even today,' Professor Bernd K. Fleischmann from the Institute of Physiology 1 explains. 'Too few implanted cells actually take on a permanent muscular function. For the prevention of cardiac arrhythmia, even a few thousand cells seem to be sufficient.'
With the skeletal muscular cells which were used for the therapy up to now, that actually does not work. 'They do not reduce the risk of a ventricular tachycardia. The opposite is true: the severity of the cardiac arrhythmia even increased in our study when we used skeletal muscular cells,' the Bonn cardiologist Professor Thorsten Lewalter emphasises. The reason for this is that for an ordered contraction it is important that the cells in the heart muscle communicate with another. To a certain extent, they pass on the 'pulse signal' to their neighbours for this. 'Real' heart muscle cells naturally have a special information channel for this purpose. We're talking about a cellular protein called Connexin 43. 'We were able to show that the embryonic myocardial cells which we implanted synthesise this protein Connexin 43, thereby allowing the electrical signal to be coupled into the infarction scar,' the heart surgeon Dr. Wilhelm Röll and physiologist Dr. Phillip Sasse explain.
New therapeutic approach
Scientists from the Institute of Genetics were successful in changing skeletal muscular cells in such a way that they also produced Connexin 43. The researchers also successfully tested these cells on mice that had had a heart attack. The risk level of a ventricular tachycardia fell to a level similar to that in healthy animals. This discovery potentially opens the door to a completely new therapeutic approach. With humans it is nevertheless not possible, for ethical reasons, to make use of embryonic heart muscle cells. 'But you could use stem cells from the leg muscle of a heart attack patient and install the gene for Connexin 43 in them,' says Professor Michael I. Kotlikoff from Cornell University in Ithaca. 'These modified cells could be then implanted in the damaged heart.' Rejection of the cells is unlikely in this case since the body would be dealing with its own (albeit genetically upgraded) cells. Bernd Fleischmann also talks about an important intermediate stage but urges caution about inflated hopes. 'Our results are valid for mice hearts,' he clarifies. 'Whether it works this way with humans has yet to be seen.'
The fact that the study was so successful was also due to the interdisciplinary nature of the project. With the Institute of Physiology 1 at the Life&Brain Centre, the Departments of Cardiosurgery and Internal Medicine II, as well as the Institutes of Genetics and Pharmacology, five research groups were involved in Bonn alone.
Prof. Dr. Bernd K. Fleischmann | alfa
Are there sustainable solutions in dealing with dwindling phosphorus resources?
16.10.2017 | Leibniz-Institut für Nutzierbiologie (FBN)
Strange undertakings: ant queens bury dead to prevent disease
13.10.2017 | Institute of Science and Technology Austria
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.
Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...
10.10.2017 | Event News
10.10.2017 | Event News
28.09.2017 | Event News
16.10.2017 | Physics and Astronomy
16.10.2017 | Earth Sciences
16.10.2017 | Physics and Astronomy