Heart Bypass Patients Improve Significantly with Adult Stem Cell Infusion

An infusion of a combination of stem and progenitor cells directly into heart attack patients' myocardium during bypass surgery improves recovery, according to a phase I study.

Researchers at TCA Cellular Therapy (Covington, LA, USA) reported the initial results of combination stem Cell (MESENDO) therapy for utilization and rescue of tissue after myocardial infarct (MI), a phase I, single center, prospective, nonrandomized, open-label study to evaluate the safety and feasibility of use of a combination of autologous bone marrow-derived stem and progenitor cells. The two bone marrow-derived cell types were mixed and implanted in the patients approximately two weeks after bone marrow aspiration. Following the transplant, the patients underwent a three-month follow-up to evaluate safety as well as functional heart improvement by analysis of symptoms, myocardial perfusion, single photon emission computed tomography (SPECT), and echocardiography.

During the trial, seven patients received the adult stem cell infusion infused directly into the heart during bypass surgery, while three control patients did not. During the follow up period, the researchers related the first two months of improvement to the results of the surgery itself, but after that, the improvements were attributed to the adult stem cells injected, included an observed increase in blood flow as well as in the pumping action of the heart. The researchers theorized that the combination cell product might promote the development of mature and stable capillaries, which will be further examined in the Phase II clinical trials. The study results were presented at International Society of Stem Cell Research (ISSCR) meeting, held during June 2010 in San Francisco (CA, USA).

"The conclusion of the study is that the treatment is safe and better improves heart function in patients who received adult stem cells during surgery, as opposed to those with only surgical bypass,” said study coauthor Gabriel Lasala, M.D., who is also president of TCA Cellular Therapy. "I anticipate that in the near future adult stem cells will be offered to patients with a history of heart attack who are going to have bypass surgery.”

The rationale of the study is based on the observation that most attempts to use adult stem cells for myocardial regeneration utilized a source of bone marrow derived progenitor cells with the potential to generate new blood vessel, and thus contribute to the revascularization of the ischemic tissue. This therapy seems to be adequate but is not sufficient, since it lacks a source of stem cells capable of differentiating and maturing into cardiac muscle cells, thus contributing to the recovery of local contractility. The proposed combination of stem and progenitor cell therapy is aimed at contributing cell types capable of regenerating both blood vessels and muscle tissues damaged after MI.

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