Scientists from the Bonn University Hospital successfully tested a method in mice allowing the morphological and functional sequelae of a myocardial infarction to be reduced. Tiny gas bubbles are made to oscillate within the heart via focused ultrasound - this improves microcirculation and decreases the size of the scar tissue. The results show that the mice, following myocardial infarction, have improved cardiac output as a result of this method, as compared to untreated animals. The study is now being presented in the professional journal PLOS ONE.
Every year in Germany, approximately 280,000 people suffer a myocardial infarction; more than 52,000 die as a result. Due to an occluded vessel, parts of the heart muscle no longer have sufficient circulation and the tissue dies off. These regions are not replaced by new heart muscle cells but instead by scar tissue – this generally causes the pump function of the heart to decrease following an infarction. Scientists from the Bonn University Hospital have now successfully tested a new method on mice with which scar tissue can be reduced and cardiac output increased.
Microbubbles are made to oscillate within the heart
"There are attempts to treat the scar tissue with gene therapy or stem cells - by contrast, we have chosen a physical approach to treatment," reports Adj. Professor Dr. med. Alexander Ghanem from the Department of Cardiology of the Bonn University Hospital. The researchers injected a total of 17 mice which had previously had a myocardial infarction with microscopically small, gas-filled bubbles in the bloodstream. Once the microbubbles reached the heart, they were made to vibrate there using focused ultrasound. "Through this mechanical stimulation, the circulation of the area of the infarction is improved - and the scar shrinks," says the cardiac specialist.
Treated animals demonstrate ameliorated post-infarction remodelling
The scientists compared the results of the mice treated with the microbubbles to those of a control group. Two weeks after the myocardial infarction, there was expected worsening of heart function in the control group due to the maturing of the scar tissue. In contrast, the mice treated with the microbubbles did not develop any cardiac insufficiency. Jonas Dörner, the first author of the study, summarizes the results: "The pumping function was significantly better in the treated animals as compared to the control group; there was also a significantly smaller amount of decayed heart muscle tissue." Along with the Department of Cardiology, the Departments of Cardiac Surgery and Anesthesiology and the Institute of Physiology took part in the investigations.
Ultrasound treatment stimulates growth hormones
The scientists sought the causes of the positive treatment success which is, however, unexplained to date. Following ultrasound treatment of the mice, it was demonstrated that the amount of the body's own growth hormones significantly increased in the heart. "This is evidently the reason why the scar formation decreased as a result of the oscillating microbubbles," says Dr. Ghanem. The scientists now hope that humans will also be able to eventually be treated with the microbubble-ultrasound method, however further investigations are still needed. "Potentially, all patients who have had an acute myocardial infarction are eligible for this follow-up treatment," explains the cardiologist of the Bonn University Hospital. Interestingly, microbubbles are already used as a diagnostic contrast agent.
Patent for novel ultrasound method filed
The study, conducted with support from the BONFOR funding program of the Medical Faculty of Bonn University and the German Heart Foundation [Deutsche Herzstiftung e.V.], gave rise to a patent application. "Together with the company Philips Medical, we developed a novel ultrasonic probe which enables a standardized impulse discharge in the heart," reports the cardiologist. The special feature is that two ultrasound sources linked together are contained in one hybrid ultrasonic probe: one with low frequency for the focused stimulation of the microbubbles in the target organ and one with higher frequency for imaging. In this way, it can be very precisely determined where the scar tissue and the microbubbles are located. "This study demonstrates again that university research inspires technological developments in medicine," says Dr. Ghanem.
Publication: Ultrasound-mediated stimulation of microbubbles after acute myocardial infarction and reperfusion ameliorates left-ventricular remodelling in mice via improvement of borderzone vascularisation, PLOS ONE, DOI: 10.1371/journal.pone.0056841, Internet: Internet: http://dx.plos.org/10.1371/journal.pone.0056841
Contact information:Adj. Professor Dr. med. Alexander Ghanem
Alexander Ghanem | EurekAlert!
New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University
Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences