University of Miami researchers explore potential of stem cell therapy to repair heart damage

In 2009, Steven Bustamante, 58, was in bad shape.

A major heart attack, along with nearly every complication in the book, had led to heart failure. He called his brother from the hospital to say his goodbyes, fearing he would fall asleep and never wake up.

But when he did wake up, an unfamiliar doctor from the University of Miami Miller School of Medicine was sitting in his room, offering him the opportunity to participate in a clinical trial where his heart would be injected with stem cells extracted from his bone marrow.

The results were transformative.

“I went from being a person who probably needed a heart transplant to someone whose heart is in a normal range,” Bustamante said. “I don’t feel like a sick person anymore, at all.”

Several studies at the UM Interdisciplinary Stem Cell Institute (ISCI) have shown that stem cells derived from adult bone marrow, which carry the potential to grow into various kinds of cells based on their environment, can help repair damaged heart tissue.

As researchers continue to explore the potential of stem cell therapy in current and upcoming studies, they are taking what some see as early but steady strides toward changing the future of cardiac care — perhaps to one in which doctors help patients regenerate and rejuvenate their own hearts.

“We’ve taken some very important steps,” said Dr. Joshua Hare, director of the ISCI, “and we really envision the possibility that this may be an applicable therapy that could help a lot of people. But there are a lot of questions.”

To answer those questions, researchers are simultaneously expanding trial sizes, branching into various cardiac diseases and trying to hone in on ideal treatment, dosage and delivery.

One of the pilot trials, published in November 2012, aimed to determine if stem cells from a donor are as safe and effective as a patient’s own stem cells. The results from 30 people showed that both types are safe — good news because donor cells can be prepared in advance.

Another study with 65 patients, published at the end of 2013, was the first to compare stem cells to whole bone marrow as well as a placebo. Bustamante was one of the participants, all of whom had weakened, damaged hearts.

Like the first study, stem cells injected directly into the heart via catheter reduced scar tissue by an average of one third, helped ‘remodel’ the heart to its healthy, football shape and improved quality of life. The cells were more effective than the bone marrow or the placebo, a vital finding for moving the therapy forward.

Dr. Alan Heldman, interventional cardiologist and member of the ISCI, delivered the actual injections in a procedure that lasts about an hour.

“I’m not ready to say that all doctors should start doing this, we’re not there yet,” Heldman said. “I try to maintain a skeptical neutrality, but I have to say I have seen some results that absolutely stunned me with the magnitude of improvement. I’m convinced we are on to something.”

Heldman and Hare echoed that one of the next big steps is finding a treatment that works even better, reducing more scar tissue faster.

Preclinical research seems to show that a combination of bone marrow stem cells and cardiac stem cells taken directly from the heart makes for a more potent treatment, even doubling the effect. This could have implications for other organs that harbor their own stem cells, like the kidney.

“It’s like a cocktail,” Hare said. “A little of this, a little of that, and you get a mixture of cells that works much better than either alone.”

The ISCI pitched the findings to the National Institute of Health, and Hare said he expects the cell mixture to head to human trials there within the next year.

“We’re fantasizing about the day when we will be able to completely eliminate the scar tissue,” Hare said. “That would be like doing a heart transplant through a catheter. It would be complete recovery.”

Meanwhile, another trial has found that stem cells are beneficial when given during heart surgery, and a current study is looking at whether stem cell injections are effective for heart disease that doesn’t cause a specific scar site. They are even looking at whether the space environment of microgravity has an effect on stem cells — an endeavor that might someday land UM researchers on the International Space Station.

Overall, these early trials, in which stem cells consistently show positive outcomes, are setting the stage for researchers who foresee a new stage of regenerative medicine.

“This may be one of the biggest, just because there is so much heart failure out there,” Heldman said. “There are so many patients, and it’s not just that they die from it, but that when they have it, they feel awful.”

As for Bustamante, today he is able to speculate about what his own future might look like — maybe retiring from his job as a public defender and moving to the West Coast.

“You go through life and you don’t think about it . . . then all of a sudden something happens and you realize you are mortal,” he said. “Thanks to what has happened, I can think about the future and doing other things and living my life.”

Amazing Times we Live In!