It's early -- results are in for only the first 16 patients -- but the results already are drawing praise from experts not easily impressed by first reports.
"This is a groundbreaking study of extreme importance," Joshua Hare, MD, director of the University of Miami's Interdisciplinary Stem Cell Institute, tells WebMD via email. Hare was not involved in the study.
"The reported benefits are of an unexpected magnitude," writes Gerd Heusch, MD, PhD, chair of the Institute of Pathophysiology at the University of Essen, Germany, in an editorial in the Nov. 14 online issue of The Lancet.
Study researcher John H. Loughran, MD, of the University of Louisville, Ky., could barely contain his excitement in an interview with WebMD.
"The improvement we have seen in patients is quite encouraging," he says. "Michael Jones, our first patient, could barely walk 30 feet [before treatment]. I saw him this morning. He says he plays basketball with his granddaughter, works on his farm, and gets on the treadmill for 30 minutes three times a week. It is stories like that that makes these results really encouraging."
The breakthrough comes just as researchers were becoming discouraged by studies in which bone-marrow stem cells failed to heal damaged hearts.
Instead of getting stem cells from the bone marrow, the new technique harvests stem cells taken from the patients' own hearts during bypass surgery. Just 1 gram of heart tissue -- about 3.5 hundredths of an ounce -- is taken.
Using a technique invented by Brigham & Women's Hospital researchers Piero Anversa, MD, and colleagues, heart stem cells are taken from the tissue and grown in the lab. These adult stem cells already are committed to becoming heart cells, but they can transform into any of the three different kinds of heart tissues.
It's the first time tissue-specific stem cells, other than bone-marrow cells, have been tested in humans, Hare says.
In the study, about a million of the cells were infused into each patient's heart with a catheter. Calculations suggest that each of these infused cells could generate 4 trillion new heart cells.
The study was designed to show whether the technique was safe. It was: No harmful effects have been seen. But to the researchers' surprise, the relatively small number of cells infused into patients had a major effect.
Of the 14 patients analyzed so far, heart function improved dramatically. And in the eight patients seen one year after treatment, improvement appears to have continued. Moreover, the scars on patients hearts -- areas of dead tissue killed during their heart attacks -- are healing.
And patients aren't just doing better on measures of heart function. Like Michael Jones, they report vastly improved quality of life and ability to perform daily tasks.