Fighting Heart Disease With Pigs? San Diego Researchers Develop New Cardiac Therapy
KPBS Midday Edition Segments / September 12, 2019
The therapy is called a hydrogel. And it can be injected directly into damaged heart muscle tissue.
Speaker 1: 00:00 Heart attack. Patients may soon get access to a new therapy. One using pig hearts. KPBS science and technology reporter Shalina Chet Lani spoke with the researcher developing this innovation. Randall Newman and his wife went on an eight mile bike ride just days before he started feeling strange. My arm started tingling. Then that's when I really was kind of what this is, right? New Man had a heart attack five years ago when he was 62 he says he was open to new therapies so he could get better. Try It, you know, everything can help that to get your heart back to where it was. One of the things he was willing to
Speaker 2: 00:37 to try was pig hearts at her lab at UC San Diego in La Jolla scientists, Karen Chrisman grinds up chemically altered pig heart tissue. This material is no longer a collection of cells because it's been turned into a fine powder and when she adds water to it, she creates a hydro Gel. A Hydro Gel is basically a physical material that's gel like um, that's water swollen. So it kind of actually the best example of a Hydro Gel. Not one we use, but the best example is Jello. After a heart attack, the heart tissue is damaged and it forms a scar so it becomes difficult for healthy cells to come in and replace this tissue. This situation can slow down the heart's performance and could lead to heart failure. So Chrisman created this hydro Gel to help repair the scarred heart tissue. When you inject in the person's heart, it sets up into a hydro Gel and serves as this new Tim template for healing inside the heart and so the body's own cells come in, migrate into it and help repair that damaged region. This gel is injected into the damaged part of the heart via a catheter. The Gel opens up the scar tissue and sticks around for about three weeks before biodegrading. When you get more cardiac muscle and less scar tissue, and so because you have more muscle, less scar tissue, you have better performance of your heart, which helps to prevent or at least slow down the progression to heart failure. This therapy has been tested in animal hearts, but Chrisman says her clinical trial is the first time it was tested in human hearts. Randall new Newman was
Speaker 1: 02:12 one of those humans and so far he's happy with the results. He says at the time of the attack, the percentage of blood leaving his heart with every pump was around 48% and then [inaudible] 62 which was almost normal. Human says that happened just a year after you finished the trial.
Speaker 3: 02:30 So the hope would be that if the hydro gel is effective, then some of the medications that we typically give to patients following a heart attack wouldn't be necessary.
Speaker 1: 02:44 UC San Diego cardiologist, Tony de Maria helped design the preclinical trials on animal models, the therapies promising. He says, especially since typical prescription drugs can often have side effects like excessive bleeding and fatigue, but the clinical trial involved 15 patients. So de Maria says there's still more to test before you could safely recommend this.
Speaker 3: 03:05 When when you're looking for safety, then you need large samples. Let's say you did a a study of 30 patients and everybody did well, but the 31st patient had some terrible reaction that would still have implications
Speaker 1: 03:23 back in her lab scientist Karen Chrisman says the experience of patients like Randall Newman shows the trial had good results. All 15 patients improved in exercise, but there was one surprise.
Speaker 2: 03:36 We have saw more changes in later patients. So those that actually had had their heart attack at least a year prior. Um, whereas we saw really less changes or no changes in the earlier patients in terms of their heart size, Chrisman says the therapies [inaudible]
Speaker 1: 03:53 it wasn't as effective in patients who had just suffered a heart attack because their bodies were still reacting to the incident and weren't as receptive to the Hydro Gel. So she says the company making this Gel is raising funds for phase two clinical trial to look specifically at how this therapy works in later stage heart attack patients joining me is KPBS science and technology reporter Shalina Chitlin. Angelina, welcome. Hi, thanks for having me. My first question is why use pig hearts to create this gel? Yes. So there are some other challenges when it comes to different animals. For example, cows could have mad cow disease. So typically scientists try to steer away from any animals that could have other diseases. And what Karen Chrisman told me is that pigs are generally known to be pretty safe. Did you find out what led researchers to come up with this idea?
Speaker 1: 04:47 Dr Chrisman was telling me that, you know, um, there's this hydro gel therapy. The idea of taking a tissues from animals and turning it into a gel, um, has been used in other parts of the human body and it's worked. And so she started to think what could happen if you have a heart attack and you have damaged scar tissue. If you put this gel into it, could it actually work? And that's how she got this idea. And do heart attacks usually cause scarring in the heart? Yeah, it's the same thing that happens when you have trauma to any other part of your body. Like for example, if you fall on your arm and scar tissue forms, it's a protective measure. Your body is trying to make sure that there, you know, other, um, elements don't come in and prevent the healing process. So yes, after you have a heart attack, um, that's just the natural body body process that happens.
Speaker 1: 05:33 So this Hydro Gel, this Jello like substance we heard about can it can actually help the body replace scar tissue with healthy heart cells. Yeah. So specifically how it works is that you is, you know, when you have a scab on your body, it's this thick material. A bunch of blood cells have come in and scabbed over. So the same thing happens on the heart. It's a really a very tough material. And so what the hydrogen l does is essentially goes into the scab. The scarred part of the heart opens it up, opens up that a rough scar tissue and allows the cells to migrate in when they otherwise wouldn't be able to. What are the possible downsides of introducing a foreign biological substance like this into, into the heart? Yeah. So there are always complications with different kinds of people. Um, different bodies might have different reactions to foreign substances.
Speaker 1: 06:26 And the FTA phase one clinical trial of this, uh, Hydro Gel from the company ventric showed it's generally safe in humans. All 15 patients, uh, didn't have any negative reactions. But in, in the feature that I reported, you know, the cardiologist Tony de Maria from UC San Diego made a good point, which is that, you know, you could have 30 patients and, and the 30th patient has a weird reaction. There is still implications to that. So that's why typically drugs like this have to go through, uh, several different clinical trials. And so this gel is going through another series of clinical trials to make sure that it's safe. Now the patient you profiled, Randall Newman had a heart attack five years ago. How long after did he participate in this clinical trial? He had done a couple of other clinical trials before this one and he didn't see many results. So I believe it was about, um, a year or so after the heart attack.
Speaker 1: 07:20 And, um, I think that contributed to why he had such a positive, um, outcome with the, with the Gel. Right. And how long did it take for him to notice any results from having this gel injected into his heart? Yeah, so there's, um, this measurement that doctors use, there's the percentage of blood that goes in and out of your heart, um, to tell how healthy your heart is. And so he says that after a year, um, of him doing the trial when he first had the heart attack is the percentage of blood being pumped into his heart was around 40%. And, uh, after a year that went into the 60s, which is almost normal. So since it, since the, there's hydrogels seemed not to work as well on people who have had recent heart attacks as it does on people who have had heart attacks couple of years ago, let's say.
Speaker 1: 08:09 Do researchers think the GL doesn't work to prevent scarring in the heart as well as it works on existing scars? I think the idea is, or at least from what I gather from Dr Chrisman is that they're still trying to figure that out, especially in the phase two clinical trial as to why that's the case. That why that was the outcome of the first trial. Um, but the theory is that, you know, when your body goes through a traumatic event, there are all sorts of processes that are happening internally that could prevent, uh, the body from being receptive to a kind of therapy. Um, so she thinks that, you know, when you first have your heart attack, your body is going through all of these different changes to try to get back to normal. So it might reject the, it, it may, it may not take onto the hydrogen as well as someone else who's in a more stable state. I see. Is there any estimate as to when a second clinical trial might begin? So there's no time line yet on when the second trial might be a doctor. Chrisman says that the company making the hydrogeology is raising funds currently to conduct the phase two clinical trial. I've been speaking with KPBS science and technology reporters. Shalina Chet Lonnie Shalena. Thank you. Thanks for having me.
Speaker 4: 09:19 Okay.