The human heart is an indispensable part of the human anatomy, so when it starts to have problems, the implications for the patient are often extremely severe. Thankfully, many brilliant researchers dedicate their lives to improving diagnosis and treatment of such conditions, like Dr. Natalia Trayanova at Johns Hopkins University. Here, Nikhil Murty discusses her work and the implications it can have for those who suffer from an especially fatal cardiac condition.
Has your heart ever skipped a beat? If it has, the odds are that you don’t have a heart arrhythmia, a condition where the heart beats irregularly, but around 6 million Americans do. This condition proves to be fatal, contributing to around 130,000 deaths a year. To treat this, people have to wear a portable defibrillator over their chests that automatically sends electrical shocks to the heart to restart it. However, this device creates new problems since the violent electrical shocks are very painful and can damage heart tissue since the electrical shocks cause all of the muscles around the heart to contract.
Professor Natalia Trayanova, PhD, Murray B. Sachs Endowed Chair and Assistant Professor Patrick Boyle, PhD, and their lab and researchers at the University of Bonn in Germany decided to solve this problem. Using a human heart model taken from a patient diagnosed with a heart arrhythmia and mice, they were able to restart the heart through optogenetic defibrillation, a method of defibrillation using light. They did it by inserting channelrhodopsin-2 (ChR2), a light sensitive protein, into the hearts and shined a red light onto the proteins, which caused the proteins to react and affect the ion channels in the cells, thereby creating electric shocks. Dr. Boyle stated “What we observed in the optogenetic defibrillation process was a gradual slowing of the arrhythmia which eventually lead to the slowing of the arrhythmia but without the abrupt punch of a typical electrical defibrillation shock.”
The Bonn researchers first tested the theory in mice by inserting the proteins into their hearts and shining the light over them to see if the hearts could be restarted, and it worked. Due to the size of the mice being so small, the Bonn had to edit the procedure and use blue light instead. The Hopkins researchers further tested a computer simulated human heart model, this time using red light. They based the model off of images of a patient with a heart arrhythmia and ran simulations, which also showed successful results. “The model itself does not cover all the parameters in a real heart,” according to Professor Trayanova, “but it is useful in guiding a future experiment. You can use the model to narrow down to useful parameters, which can let you explore a much narrower pathway.”
How would this optogenetic defibrillation work in the real world? In terms of the application of the proteins into the heart, Dr. Trayanova said that they will have to be inserted in advance because they need to travel into the heart and bind to the cells. Therefore, some work in drug delivery will be needed. She also talked about a sort of device that could in a sense wrap around the heart, so that when the person suffered from an arrhythmia, it would automatically shine the red light over the heart, activating the proteins.
Nevertheless, Professor Trayanova’s research aims to further understanding the molecular intricacies of the heart, promoting robust clinical therapies and a refined understanding of the beauty of all of its molecular and electrical coordination.