"So," said Dimmeler, who was not involved in the new study, "it might be interesting to have cells 'off-the-shelf'" that were grown earlier, using an outside donor's cells.
But would these donor cells perform as well as the patient's own?
In the new study, Hare and his colleagues investigated that question with 30 patients who all had damaged, enlarged hearts due to a prior heart attack. Half received infusions of their own mesenchymal stem cells, while the other half received cells sourced from young, healthy donors. The patients were then tracked for 13 months.
While the amount of cardiac scar tissue typically does not change for heart failure patients, Hare said that on CT scans "we saw a 33 percent reduction in scar tissue in both [the donor and self-sourced] groups." Swollen, misshapen hearts also began to change back to a healthier, spherical shape, indicating that scar tissue was receding, he said.
According to Hare, all of this "is very important because we think that this is the basis by which this therapy is going to work."
Patient function also seemed to improve, regardless of where the cells were sourced from. In terms of quality-of-life scores, "there was an improvement in both groups that was clinically meaningful," Hare said. Patients from both groups improved at similar rates on a special six-minute-walk test, for example.
Finally, the use of donor stem cells appears to be safe: only one patient out of 30 had any immune reaction to the procedure, and that reaction was "at a very low level," Hare said.
Still, Dimmeler stressed that, though encouraging, more and much larger trials are needed, and those could take years.
"I think it is still early days," she said. "Although we are having [stem] cells in the clinic being tested, it's all so far at ve
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