Docs fix hearts with stem cell injections

Doctors have rejuvenated post-heart attack patients by injecting them with stem cells, said two studies released Sunday.

The clinical trials delivered stem cells to hearts whose stiff, post-attack scar tissue kept them from pumping blood as they should, according to the studies presented at the American College of Cardiology meeting of 30,000 specialists in New Orleans, Louisiana until March 27.

One of the trials used stem cells from bone marrow, a first for cardiology, according to the study's lead author, Joshua Hare of the University of Miami medical school in Florida.

Among stem cells's many advantages is that they can be harvested from donors genetically dissimilar to the recipient, and they attach themselves at the point of an injury, Hare told reporters.

Hare and his team injected intravenously 53 patients within 10 days of a heart attack. They randomly assigned patients different doses (0.5 million 1.6 million or 5.0 million cells per kilogram) and compared the dosages with a placebo.

Over six months, the patients receiving the stem-cell treatment had better heart and lung function with fewer arrhythmias.

Echocardiography also showed better heart function, especially in patients with greater heart damage.

"This trial makes an important contribution in the field of stem cell-based treatments for heart disease by providing safety and efficacy data for a unique and promising type of stem cell to treat cardiac damage," Hare said.

"This study represents a first step," Hare said. "We must perform additional and larger trials to determine the real-world application of (marrow stem cells) to fight heart disease."

The second study tested stem cells taken from the patients' own muscle tissue.

Nabil Dib of the University of California led the team testing 23 patients with progressive, congestive heart failure.

Researchers gave the control group of 11 patients standard drug treatments, while those in the treatment group received doses of 30 million, 100 million, 300 million or 600 million muscular stem cells injected into their hearts.

After six months the stem-cell recipients had markedly improved quality of life, while the control group worsened.

"Transplantation using a minimally invasive catheter is safe, showed improvement in quality of life and may have the potential to improve cardiac function," Dib said.

The US Food and Drug Administration, which vets trials, will allow a phase II randomized, double-blind, placebo-controlled clinical trial for up to 160 patients, he said.