George Reed's heart wasn't doing so well: He's 71, and after suffering a heart attack years earlier, Reed had undergone open heart surgery and was put on multiple medications. But nothing seemed to help the dizziness and chest pain he experienced daily.
"I'd get dizzy and just fall over -- sometimes twice a day. I would run my head into the concrete. I was a bloody mess," the Perry, Ohio, native says. Despite his doctor's best efforts, Reed continued to experience angina, a type of chest pain that occurs when the heart doesn't get enough oxygen-rich blood; it can be accompanied by dizziness. So when he was recommended for an experimental study that would inject his own stem cells into his damaged heart, Perry signed on. "I needed something to change," he says.
Researchers gave Reed a drug commonly used in bone marrow transplants that stimulates the marrow to make more stem cells. Then they removed some of Reed's blood, isolated the stem cells and injected them into and around the damaged areas of his heart.
"The goal was to grow new blood vessels with stem cells from the patient's own body," says Dr. Tim Henry, a co-author of the study and director of research at the Minneapolis Heart Institute Foundation.
Within a few months, Reed, along with many of the other 100 or so patients at 26 hospital centers who'd received this stem cell treatment, reported feeling better than he had in years.
"When it started kicking in, I felt like a kid. I felt good," Reed says. He wasn't passing out and falling down anymore.
For Jay Homstad, 49, who was part of the Minnesota branch of the study, he felt the changes most in his ability to walk and be active.
"My activity level increased tenfold. Before, I struggled with chest pain every day. My activity level was about as close to zero as you could get. Now I can participate ... just in life. It may sound silly, but the best part is that in the wintertime I could go out and walk with my dog along the Red River. When you're walking through snow that is waist deep, you can tell there's a difference," Homstad says.
Homstad had had about a dozen surgeries and nine stents put in before he enrolled in the study, but he still struggled with angina daily. Within a few months of the stem cell shots, he could walk farther, and his chest pain subsided and was kept at bay for nearly four years.
"These are people for whom other treatment hasn't worked. They're debilitated by their chest pain, but their other options are really limited, that's why we picked them," says Henry. If the positive results seen in this study hold up in the next phase of the study, which is set to begin enrollment in the fall, this type of cardiac stem cell injection could be added to the arsenal of weapons against angina. The upcoming phase three trial has already been approved by the Food and Drug Administration.
Shot to the Heart, Before It's too Late
While several smaller studies have suggested that injecting stem cells into damaged heart tissue might be effective, this study, in its scope and rigor, was the first of its kind. A total of 167 patients were recruited and randomly assigned to receive a lower dose of stem cells, a higher dose or a placebo. The patients didn't know who got what treatment, and neither did the doctors treating them.
When tracked for a year after the injection, patients who received the lower dose of stem cells could last longer during a treadmill exercise than those who had received the placebo, and they averaged seven fewer episodes of chest pain in a week. To put this in perspective, a popular drug to treat angina, Ranolazine, reduced chest pain by fewer than two episodes a week in clinical trials.
Although the goal of the stem cell shots was to grow new blood vessels, it's impossible to tell if these stem cells were actually growing into blood vessels or if they were just triggering some other kind of healing process in the body, Henry says. Tests in animal models, however, do suggest that new blood vessels are forming, says Dr. Marco Costa, a co-author of the study and George Reed's doctor at UH Case Medical Center in Cleveland.
For now, the only gauge of the injections is improvement in symptoms.
Despite the positive results of the study, cardiologists remain "cautiously optimistic" about stem cells as a treatment for angina.
"The number of patients is relatively small, so this trial would probably not carry much scientific weight," says Dr. Jeff Brinker, a professor of cardiology at Johns Hopkins University. The results did justify the next, larger trial, he says, which would offer more answers as to whether this treatment is actually working the way researchers suspect.
The fact that lower doses of stem cells were puzzlingly more effective than larger ones is cause for caution, says Dr. Steve Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic.
"The jury is still out for stem cell therapies to treat heart disease," says Dr. Cam Paterson, a cardiologist at the University of North Carolina at Chapel Hill.
But the results so far provide cautious hope for heart patients like George Reed and Jay Homstad.