IF YOU suffer a heart attack, a dose of your own stem cells could help repair the damage. Preliminary studies by two groups suggest that injecting stem cells directly into damaged hearts helps to restore their function.
Heart attacks, one of the West’s biggest killers, are usually caused by fatty deposits that block the arteries supplying blood to heart muscle. This starves a chunk of muscle of blood, and eventually kills it. An operation to bypass the blockage can restore blood flow and prevent further damage, but much of the dead heart tissue never recovers, leaving the patient disabled. “If a large area is lost, they can have severe loss of activity,” says Gustav Steinhoff at the University of Rostock in Germany.
One possible treatment is to encourage surviving cells to regenerate using growth factors or the genes that code for them, but this has had only limited success. So researchers have tried using stem cells, which have the ability to turn into tissues such as heart muscle. One study reported an improvement in heart function after simply injecting stem cells into patients’ blood.
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Now two groups have gone a step further by injecting stem cells directly into the heart (The Lancet, vol 361, p 45 and p 47). Steinhoff’s group in Germany purified stem cells from bone marrow removed from six patients’ hips. The next day, during a bypass operation, they injected the stem cells into the boundary between living and dead heart tissue.
For all six patients, the heart’s strength and blood supply improved, suggesting the stem cells had differentiated into heart muscle and blood vessel cells. A group in Japan reported similar results using less purified stem cells injected via a catheter without bypass surgery.
The improvements in the bypass patients were much greater than those from the bypass operations alone. But Steinhoff stresses that this was a preliminary feasibility study, without a control group given only bypass surgery.
Using a patient’s own stem cells means there is no risk of rejection, or of introducing diseases from a donor. But the purification process is time-consuming, which is why there is a day’s delay between extraction and injection.
“Hours are important [after a heart attack],” says Peter Oettgen, who studies blood vessel development at Harvard Medical School. “It is hard to get recovery unless treatment is applied quickly.”
