"Scientists report another step in the use of stem cells to help treat people with debilitating heart failure. In an early study of  patients Japanese researchers used patients own muscle stem cells to create a patch that was placed on the heart. Over the next year the patients generally showed small improvements in their symptoms  including the ability to walk without becoming breathless and fatigued. However experts cautioned that while the results are encouraging theres a lot of work left ahead before stem cells can be used to treat heart failure. Theyve shown that this approach is feasible said Dr. Eiran Gorodeski a heart failure specialist at the Cleveland Clinic in Ohio. But its not clear whether the stemcell tactic was actually effective said Gorodeski who was not involved in the study. Thats because the study didnt include a comparison group that did not receive stem cells. So its possible Gorodeski explained that the modest symptom improvements would have happened anyway. All of the patients were on standard medications and some had heart devices implanted. Stem cells are primitive cells that mature into the various cells that make up the bodys tissues. In the past  years or so scientists have tried to use the cells to help repair some of the damage seen in heart failure. Heart failure is a progressive disease where the heart muscle is too damaged to efficiently pump blood throughout the body. It often arises after a heart attack. Symptoms of heart failure include fatigue breathlessness and swelling in the limbs. The condition cannot be cured although medications and implantable devices can treat the symptoms. In the new study the researchers used stem cells from the patients own thigh muscle to create a patch they placed on the heart. Thats in contrast to many past studies where researchers have injected stem cells  often from patients bone marrow  into the heart. The patch tactic could have some advantages said senior researcher Dr. Yoshiki Sawa of Osaka University. He said animal research suggests that cells in sheet form survive for a longer period compared to injections.  To test the safety of the approach Sawas team recruited  patients who had debilitating symptoms despite standard heart failure therapies. The scientists extracted stem cells from each patients thigh muscle then cultured the cells so that they formed a sheet. The sheet was placed on each patients heart. The tactic appeared safe the researchers said and there were signs of symptom improvements over the next six months to a year. Why would stem cells from the thigh muscle affect the heart Its not clear Sawa acknowledged. The stem cells dont grow into new heart muscle cells. Instead Sawa explained they seem to produce chemicals called cytokines that can promote new blood vessel growth in damaged areas of the heart. The theory he said is that hibernating cells in the heart muscle can then function better. Still its too soon to know what the new findings mean said Gorodeski. This type of trial called phase  is designed to look at the safety and feasibility of a therapy Gorodeski said. It takes laterphase trials  where some patients receive the treatment and others do not  to prove that a therapy actually works. Those trials are underway Sawa said. Other studies are further along. Last year researchers reported on a trial testing infusions of stem cells taken from the bone marrow of patients with severe heart failure. Patients who received the therapy were less likely to die or be hospitalized over the next year versus those given standard treatment only. But the study was small and the stem cells had only a minor impact on patients heart function. So its not clear why the stemcell patients fared better Gorodeski said. For now he stressed all stemcell therapies for heart failure remain experimental. Theres no cell therapy that we can offer patients right now Gorodeski said. The message for patients he added is that heart failure can be treated and researchers are looking for innovative ways to improve that treatment. The study was published April  in the Journal of the American Heart Association. More information The American Heart Association has more on heart failure http_UCM__Article.jsp. SOURCES Yoshiki Sawa M.D. Ph.D. professor cardiovascular surgery Osaka University Graduate School of Medicine Osaka Japan Eiran Gorodeski M.D. M.P.H. staff cardiologist assistant professor medicine Cleveland Clinic Ohio April   Journal of the American Heart Association online"