Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Termination of lethal arrhythmia with light

13.09.2016

A research team from the University of Bonn has succeeded for the first time in using light stimuli to stop life-threatening cardiac arrhythmia in mouse hearts. Furthermore, as shown in computer simulations at Johns Hopkins University, this technique could also be used successfully for human hearts. The study opens up a whole new approach to the development of implantable optical defibrillators, in which the strong electrical impulses of conventional defibrillators are replaced by gentler, pain-free light impulses. The "Journal of Clinical Investigation" has now published the results.

! When the heart muscle races and no longer contracts in an orderly fashion, sudden death often follows due to the lack of blood circulation. In such an emergency, a defibrillator helps to restore normal heart activity by means of intense electrical shocks.


A: Optogenetic defibrillation (blue bar) stops arrhythmia in mouse heart. B: Simulation of optogenetic defibrillation (red bar) in a model of a human heart.

© Image: Tobias Brügmann (University Bonn)/Patrick M. Boyle (Johns Hopkins University)

In patients with a known risk for these arrhythmia, the prophylactic implantation of a defibrillator is the treatment of choice. If ventricular fibrillation is detected, a pulse of electricity is automatically generated, which normalizes the excitation of the heart muscle and saves the person's life.

"When an implanted defibrillator is triggered, which unfortunately can also happen because of false detection of arrhythmia, it is always a very traumatic event for the patient", says the head of the study, Junior-Professor Philipp Sasse of the Institute of Physiology I at the University of Bonn.

"The strong electrical shock is verVentricular fibrillationy painful and can even damage the heart further". Therefore, Professor Sasse's team investigated the principles for a pain-free, gentler alternative. As the scientists have now shown, ventricular fibrillation can be stopped by optical defibrillation.

Optical defibrillation requires gene transfer

The team used the new method of "optogenetic" stimulation of mouse hearts, which had genes inserted for so-called channelrhodopsins. These channels are derived from a green algae and change the ion permeability of heart cell membranes when illuminated. When the researchers triggered ventricular fibrillation in the mouse heart, a light pulse of one second applied to the heart was enough to restore normal rhythm. "This is a very important result", emphasizes lead author Dr. med.

Tobias Brügmann of Professor Sasse's team. "It shows for the first time experimentally in the heart that optogenetic stimulation can be used for defibrillation of cardiac arrhythmia". It also worked in normal mice that received the channelrhodopsin through injection of a biotechnologically-produced virus. This shows a possible clinical application, because similar viruses have already been used for gene therapy in human patients.

Simulations show that findings could be applied to patients

But are the findings with mouse hearts applicable to humans? In order to answer this question, the scientists at the University of Bonn are working together with Prof. Natalia Trayanova’s Computational Cardiology Lab at the Institute for Computer Medicine and the Department of Biomedical Engineering at Johns Hopkins University (Baltimore, USA). There, optogenetic defibrillation is being tested in a computer model of the heart of a patient after cardiac infarction.

"Our simulations show that a light pulse to the heart would also stop the cardiac arrhythmia of this patient", reports Research Professor Patrick Boyle, who is also a lead author. To do so, however, the method from the University of Bonn had to be optimized for the human heart by using red light to stimulate the heart cells, instead of the blue light used in mice. This aspect of the study demonstrates the important role that can be played by computational modelling to guide and accelerate the systematic development of therapeutic applications for cardiac optogenetics, a technology that is still in its infancy.

Implantable optogenetic defibrillators could be feasible

"Our data show the fundamental feasibility of optogenetic defibrillation for the treatment of ventricular fibrillation", summarizes Prof. Sasse. Using light to return the fibrillating heart to a normal rhythm can be expected to be pain-free and much gentler for the patient than the use of electric shock. However, the new method is still in the stage of basic research. Until implantable optical defibrillators can be developed for the treatment of patients, it will still take at least five to ten years, estimates Prof. Sasse.

Publication: Optogenetic defibrillation terminates ventricular arrhythmia in mouse hearts and human simulations, "Journal of Clinical Investigation", DOI: 10.1172/JCI88950

Contact for the media:

Junior Prof. Philipp Sasse
Institute of Physiology I
University of Bonn
Tel. +49-228-6885212
E-mail: philipp.sasse@uni-bonn.de

Dr. Tobias Brügmann
Institute of Physiology I
University of Bonn
Tel. +49-228-6885217
E-mail: tbruegmann@uni-bonn.de

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de/

More articles from Medical Engineering:

nachricht Visualizing gene expression with MRI
23.12.2016 | California Institute of Technology

nachricht Illuminating cancer: Researchers invent a pH threshold sensor to improve cancer surgery
21.12.2016 | UT Southwestern Medical Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

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...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

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...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Solar Collectors from Ultra-High Performance Concrete Combine Energy Efficiency and Aesthetics

16.01.2017 | Trade Fair News

3D scans for the automotive industry

16.01.2017 | Automotive Engineering

Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs

16.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>