According to the World Health Organization, the number one cause of death in the world is cardiovascular diseases. Of the nearly 18 million people who died from cardiovascular diseases in 2016, up to 85 percent of them were due to heart attack and stroke. Despite research advances to improve cardiovascular health, heart failure after a heart attack is still a primary cause of death. Recent research has focused on how healthy hearts are created and how cardio muscle cells (known as cardiomyocytes) take part in a complicated process of building the heart muscle and then lose their ability to regenerate. Because large numbers of cardiomyocytes are destroyed in a heart attack, heart failure from scar tissue is a natural consequence. However, studies using postnatal mammals are offering hope that genetic therapy might spur cardiomyocytes to rebuild damaged hearts.
A 2019 study using mice looked at the short and long term effects of injecting the damaged heart muscle with genetic material called miR-19a and miR-19b-1 from stem cells to see if the damaged cells would repair. Two months after the heart attack (i.e., myocardial infarction), the scar tissue in the damaged hearts had decreased. In addition, the cardiac function of the mice injected with this genetic material had improved compared to the control mice who had not received the injection. Cardiomyopathy, where the heart muscle struggles to pump blood to the body, was reduced when measured two months after the injection.
Timing of the gene therapy injection also proved to be important in this study. Researchers discovered that genetic therapy worked best at 2-4 weeks after a heart attack and again at 4 months post-heart attack. Gene therapy appeared to reduce the immune response of the heart in the early heart attack stages which supports previous connections made between inflammation and heart attacks. Interestingly, cardiac function was typically safeguarded up to a year if the gene therapy injection was done at the same time as the instigation of the heart attack in mice.
In another study, this one from 2019, British researchers at King’s College, London, used gene therapy in pigs to see if cardiac function after myocardial infarction was restored. After injecting genetic material called microRNA-199 into a pig’s heart after an induced heart attack, they discovered that the pig recovered almost all its cardiac function 30 days later. The importance of this study is that it shows the success of gene therapy in a larger mammal with a heart similar to a human heart.
While clinical trials using human subjects are still in the future, the promise of gene therapy to help the heart rebuild itself after a heart attack is encouraging. By minimizing inflammation and reducing scar tissue, cardiac function can likely be restored. If you or a loved one are suffering from the effects of heart failure as the result of a heart attack, ask your doctor about the latest developments with gene therapy. Doctorpedia is encouraged by the research about gene therapy and its positive effects on the heart after a heart attack. You should be encouraged, too!
Nan Kuhlman is an author, freelance writer, and part-time university professor based in Los Angeles, CA. She currently works full-time as a technical writer in Los Angeles and part-time as an online adjunct writing instructor. She has written for scholarly publications like the University of California, Davis Writing on the Edge and Chapman University’s Anastamos Interdisciplinary Journal, among others.