Heart disease is the No. 1 cause of death in the United States, accounting for one in four deaths. While much has been learned about the risk factors for and the pathophysiology of heart disease and major advancements have been made in the pharmacologic and surgical treatment of this condition, we remain technologically naive in our ability to fix these "broken hearts." As we wrap up National Heart Month, I thought it would be valuable to explore this question of can science and technology fix a broken heart?
To help answer this question, I had a conversation with Dr. Adam Feinberg, professor and biomedical researcher at Carnegie Mellon University's College of Engineering. Dr. Feinberg and his colleagues at Carnegie Mellon are working to "fix broken hearts through engineering." Conversations like this one -- between a clinical cardiologist like myself and a biomedical researcher like Adam -- can help provide the public with a better understanding of the complex nature of current heart treatments, and also give us some insight into how new research will impact our future.
For this week's post, I asked Dr. Feinberg to help explain the current state of cardiovascular treatment and heart-related biomedical engineering. In an upcoming piece, we'll break down the innovative projects that he has underway at CMU that get to the heart of our problems with heart treatment.
Q: What is the biggest problem facing heart treatment today? What makes fixing a heart different from another organ?
A; For heart disease, a major problem is that the muscle cannot regenerate (or repair itself). For example, when you have a heart attack, what happens is that part of the heart muscle dies and is replaced by stiff scar tissue that cannot contract. This makes the heart as a whole weaker; it can't pump as much blood, and to compensate, the remaining healthy heart muscle has to work harder. Eventually, the heart becomes so weak that it cannot supply enough blood to the body; this is heart failure, and if untreated will lead to death.
Q: Wernher von Braun, when asked by President Kennedy what it would take to send man safely to the moon and back, replied, "The will to do it." I know you and your colleagues at Carnegie Mellon have the vision and the will, so I imagine you are at the verge of a exciting breakthrough. Why haven't we been able to resolve this issue until now? What has been holding us back?
A: The challenge is that the heart is really a remarkable organ. It's small, lightweight, operates for billions of cycles over multiple decades, and can even get stronger through exercise. Most importantly, it does all of this without damaging blood cells or causing blood clots. This last point has proven to be the major challenge for mechanical and artificial heart assist/replacement technologies.
Q: How do we currently tackle treating this problem, and why is it so important to change the status quo?
A: As engineers, we would like to be able to build a replacement mechanical heart, but this has proven far more difficult than anyone ever envisioned. Ventricular Assist Devices (VADs) that take over some of the pumping of the heart are clinically-approved and work. However, Total Artificial Hearts, such as the Jarvik mechanical heart first implanted into humans in the early '80s or more recent efforts by Abiomed, Inc., do not have adequate performance. The de facto therapy for end-stage heart failure is still a heart transplant, but there is a very limited supply of donor organs and many patients do not qualify for transplant due to other complicating factors.
Q: How are researchers like yourself working to change this? What's your vision for the future of heart treatment?
A: The fact that heart transplantations work suggests that if we could repair or regenerate patients' hearts, or engineer replacement biological hearts, we would be able to treat the vast majority of heart failure patients that currently have no long-term solutions. This isn't easy to do, but there are a large number of scientists, engineers and physicians working on this challenge from multiple directions. For example, it is clear that we need pluripotent stem cells in order to create new human heart muscle cells. It may be possible to simply inject these cells into the damaged heart to repair it, which many researchers are pursuing. However, my experience suggests that we need to do more by actually guiding these newly-created heart muscle cells into a functioning muscle tissue outside of the body first.
Q: What has your research accomplished so far? How does it fit into the "big picture" of heart treatment?
A: My research group is building new technologies to build heart muscle tissue in the lab. We call this "biofabrication," and we are doing this using both a nanotechnology approach, which is funded by the American Heart Association (AHA) and the National Institutes of Health (NIH) New Innovator Award as well as a 3D bioprinting approach, which is funded by the National Science Foundation (NSF) CAREER Award. Uniquely, we are studying the way the heart forms during embryonic development, the only time new heart muscle forms in the human, and using this to develop principles that we can apply to growing new human heart muscle in the lab. The big picture is that we can initially create heart muscle in the lab to study basics of disease mechanisms, then translate this into a platform for screening the effects of drugs on heart muscle, and then ultimately create heart muscle grafts that could patch a damaged heart.
It's clear that the heart is an immensely complex organ that, historically, has been difficult to repair. Meanwhile, research like Dr. Feinberg's gives us reason to be optimistic about the future of fixing broken hearts. Stay tuned for my next post when Dr. Feinberg and I will explore some of these exciting innovations further.
My book, Your Vibrant Heart, includes many more insights about how to nurture and care for your heart on both a physical and emotional level. For the month of February, I am providing a free electronic download of my best selling book, Your Vibrant Heart. Click here for the download. You can also purchase a physical copy on Amazon.