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Q&A With Heart Researcher James F. Dawkins

By Applying His Background in Veterinary Medicine, Dawkins Has Helped Discover New Ways to Repair the Human Heart

Research scientist James F. Dawkins, DVM, has kept busy since joining Cedars-Sinai in 2011, having worked on several groundbreaking investigations into how heart cells can be used to repair the body’s own tissues. 

But it wasn’t medical research he was initially interested in. Dawkins recently spoke with the Cedars-Sinai Newsroom about how he transitioned from caring for horses to studying the heart.

Newsroom: You trained as a veterinarian. How did you become interested in doing medical research?

Dawkins: During veterinary school, I was primarily interested in equine sports medicine, did several internships and spent most of my free time with horses. I was able to work with and care for thoroughbred racehorses at various tracks in Southern California. My earliest mentor was extremely interested in regenerative medicine, including stem cell therapy to reduce scarring and promote healing in athletic horses, which commonly experience soft tissue injuries. Upon graduation, the field of equine sports medicine was undergoing some changes, with limited employment opportunities. So, I decided to pursue an equally passionate interest, which was cardiology. I saw that Dr. Eduardo Marbán's lab was doing heart failure research using a large animal model, and I thought, 'This is interesting. Let me try this.'

Newsroom: What interests you about cardiology?

Dawkins: The heart is the essential organ in the body. It drives our entire lives, inside and out. How our hearts beat throughout our lifetime is something that we do not fully understand. There is something about a particular group of cells that serve as our natural pacemaker, allowing them to beat over a billion times in a person's life; that's just a fantastic and fascinating thing. There is nothing else in the body like it.  

Newsroom: Your work involves studying how the heart's cells can be used to repair itself. Can you explain?

Dawkins: Essentially, we take a piece of a heart, and in our lab, we grow spherical aggregates of cells, which we know as cardiospheres. From this, we derive individual cells, and importantly, we isolate transport vesicles from these cells. These transport vesicles contain genetic material reparative in the face of disease.

Newsroom: These cardiosphere-derived cells are cells with therapeutic properties?

Dawkins: Yes, they've grown from cardiac tissue and contain healing properties. One of my contributions is optimizing those properties while realizing them into a deliverable system for patients—specifically, catheter-based delivery directly to targeted locations in the heart. This is where a pig model is extremely beneficial, as the equipment we use can be directly translated for use in human patients.

Newsroom: What are you working on now?

Dawkins: We recently published a paper in the European Heart Journal describing how we're using extracellular vesicles, or exosomes, generated by cardiac stem cells, to reduce scarring in areas of the heart that could serve as a nidus or substrate for fatal arrhythmias. We have taken these exosomes and developed focal delivery techniques optimized in large animals, allowing us to repurpose them to prevent irregular heartbeats associated with disease, which can lead to sudden death. 

Newsroom: You've also worked on developing a "biological pacemaker." Could you explain that?

Dawkins: Yes, a biological pacemaker is precisely what it sounds like. The difference between that and our innate pacemaker is that we are reprogramming otherwise quiescent heart cells by modifying their genetic memory in the way our natural pacemaker cells developed before birth.

Newsroom: What would be the benefits of a biological pacemaker over the traditional pacemaker?

Dawkins: If you were a candidate for a  biological pacemaker, you would not have to have any hardware in your body. We have learned that the high burdens of pacing by mechanical pacemakers contribute to cardiomyopathy, a disease that affects the heart muscle. A biological pacemaker can ease the restoration of good heart function for patients with conduction disorders. A permanent and natural pacemaker is an attainable goal in our lifetime, and I enjoy being able to contribute.

Newsroom: What do you see as the most promising development that may one day make its way to many patients?

Dawkins: I think we will be able to curb post-heart attack arrhythmias in our time. We begin by limiting the risk of post-heart attack patients. We do this by understanding that their chances of sudden death or limiting the frequency where they would need an emergency intervention.

Newsroom: How does your veterinary medicine background lend itself to your work as an investigator?

Dawkins: Well, I'm very familiar with animal anatomy and physiology, so aligning those interests with human physicians and scientists has been excellent. I have had some incredible individuals and colleagues who I have been able to work with and learn from during my time at Cedars-Sinai. They continue to contribute to my understanding of human disease.

Newsroom: What is the process for staying involved in research?

Dawkins: Research is a community effort led by the nature to understand ourselves. Our collective curiosity follows many threads. One good question leads to another; however, mammalian biology has more threads than a sweater. I enjoy showing up to the lab every day and asking those scientific questions—How can we improve this? How can we further optimize previous discoveries—all the while contributing to the advancement of understanding. That is what I enjoy.