How Are the First Stem Cell Therapies Doing?

The first, comparatively simple, regenerative medicine procedures isolate stem cells from a patient and then return them to the body to promote healing. This is the methodology used in trials with heart disease patients since 2002. In many ways, this is a banner therapy for stem cell medicine as a whole - despite using adult stem cells and having little to do with therapeutic cloning. It is the first therapy based on stem cells likely to see widespread use and success.

(For the purposes of this post, I'm ignoring stem cell transplants from bone marrow between matching donors - that could be regarded as a more sophisticated form of old style bone marrow donation).

The latest published information on a human trial of this stem cell based heart disease therapy (held in South America because the FDA would not allow trials to take place in the US through most of 2003 and early 2004) is promising. A ScienceDaily article on the study summarizes some of the results:

Amit Patel, M.D., from the Division of Cardiac Surgery at the University of Pittsburgh School of Medicine and a faculty member of the university's McGowan Institute for Regenerative Medicine, and colleagues from the University of Pittsburgh, Baylor University Medical Center in Dallas and the Department of Cardiovascular Surgery at the Benetti Foundation in Rosario, Argentina, say their findings provide the first convincing evidence that transplantation of adult stem cells that promote growth of blood vessels and heart muscle can be a viable treatment for congestive heart failure. While some previous studies have suggested benefit, results of these studies have been questioned due to the small number of patients studied and lack of comparison data from patients not receiving the therapy.

The study involved 20 patients with severe heart failure (New York Heart Association heart failure classification III and IV) who had ejection fractions less than 35 percent. Ejection fraction is a standard measure of heart function and is determined by the total amount of blood that the left ventricle pumps out per heart beat. A patient with good heart function has an ejection fraction of at least 55 percent. Each patient was scheduled for off-pump (beating heart) cardiac bypass surgery; 10 were randomized to also receive stem cells during surgery. The other 10 patients underwent the bypass operation alone. Each group consisted of eight men and two women.

Before surgery, the average ejection fraction in the patients randomized to bypass surgery alone was 30.7 percent with a range of 26 to 34 percent. The patients randomized to receive stem cells in addition to bypass surgery had an average ejection fraction of 29.4 percent before treatment, with a range of 23 to 34 percent.

At one-, three- and six-month follow-up, the ejection fraction rates for the stem cell patients were significantly improved compared to the other patients. ... At six months, the average ejection fraction rates were 46.1 and 37.2 percent, respectively, with ranges of 44 to 50 percent in the stem cell patients and 33 to 44 percent in the bypass alone group.

So the goal to attain bare minimum healthy functioning was an improvement by 25 percentage points of ejection fraction in this group. Stem cell therapy plus bypass surgery looks to be about twice as effective as the surgery alone, a difference that puts the recipients within striking distance of healthy heart function. Pretty impressive stuff.

Heart disease is a form of muscle damage, and as such it is open to this sort of comparatively simply process. Imaging what scientists will be able to achieve with more knowledge and control of stem cells and their usage!

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