Injectable Pig Heart Tissue Is the Future of Recovering From Heart Attacks

No, it's not a horror movie plot.

pig

It may sounds like the first act of a science fiction horror film, but doctors injecting liquified pig heart cells into humans really were trying to heal them. And early reports suggest they succeeded.

New research in the Journal of the American College of Cardiology: Basic to Translational Science shows evidence that a substance called VentriGel, which is made from pig heart cells, can be safely injected directly into the hearts of patients who have survived heart attacks.

In a paper published on Wednesday, a team of researchers presented the results of a Phase 1 trial on 15 patients who had survived a heart attack between two months and three years prior. While a Phase 1 trial is just meant to establish that a therapy is safe, some of the patients showed some noticeable health improvements, suggesting that their hearts had been strengthened by the substance. Needless to say, the team was encouraged.

In patients age 45 or older, there’s a 20 percent chance that they’ll experience another heart attack within 5 years. In addition to the lifestyle factors such as exercise and diet that can make a person more prone to heart attacks, the experience itself leaves the heart damaged in ways that can make subsequent heart attacks likely. Specifically, a heart attack leaves scar tissue that can cause ongoing weakness and increase the potential for future issues. So the goal of VentriGel is to assist the heart in regaining strength.

graphic abstract for pig cardiac cell therapy

VentriGel is made by taking connective tissue from pigs’ hearts, stripping it of its heart cells, drying it, and grinding it to a powder. The idea behind it is that once it’s in the hearts of humans, it will form a scaffold on which muscle cells can grow. The substance was designed by Ventrix, Inc, a company owned by several of the paper’s co-authors, including Karen Christman, Ph.D., the paper’s senior author and a professor of bioengineering at UC San Diego.

“Although the study was designed to evaluate safety and feasibility and not designed to show whether VentriGel effectively helps improve heart function, we observed some improvements in patients,” Christman said in a statement. “For example, patients could walk longer distances. We also observed signs of improving heart function in patients who experienced a heart attack more than one year prior to treatment.”

Only one of the patients experienced an adverse event, but the paper’s authors write that a pre-existing blockage condition may have contributed to that outcome. They excluded any further patients from the study who had it.

As shown in the above diagram, to use the substance, doctors inserted a catheter into each patient’s heart and injected VentriGel directly. In followups 3 and 6 months later, patients performed walking tests and received MRIs to observe how their hearts were recovering. These tests revealed some of the early signs that VentriGel is a viable therapy, but they’re not enough.

The team is starting Phase 2 trials soon, which will begin gathering evidence on whether VentriGel really works.

Abstract: This study evaluated the safety and feasibility of transendocardial injections of VentriGel, a cardiac extracellular matrix hydrogel, in early and late post–myocardial infarction (MI) patients with left ventricular (LV) dysfunction. VentriGel was delivered in 15 patients with moderate LV dysfunction (25% ≤ LV ejection fraction ≤ 45%) who were between 60 days to 3 years post-MI and were revascularized by percutaneous coronary intervention. The primary endpoints were incidence of adverse events and abnormal clinical laboratory results. This first-in-man study established the safety and feasibility of delivering VentriGel in post-MI patients, thus warranting further evaluation in larger, randomized clinical trials.