( CNN ) -- Dr. Roberto Bolli 's face lights up when he talks about his true love : the human heart . `` The heart is really a miraculous organ . It beats 72 times a minute throughout our life , which means billions of times in our lifetime . And it never gets tired , '' Bolli says . `` It knows exactly how much blood to pump ; it can increase its output by fivefold if we need more oxygen -- for example , if we 're running or doing strenuous activity . You have 5 billion cells called myocites , all beating in synchrony , in a perfectly coordinated manner , to maximize the heart 's pumping ability . It is an engineering feat that never ceases to amaze me . '' Bolli was born in Perugia , Italy , the son of a general practitioner . He came to the United States after finishing medical school in Italy , starting at Baylor College of Medicine in Houston . Since 1994 , he 's been the chief of cardiology at the University of Louisville , where he also directs the Institute of Molecular Cardiology . Like most physicians , Bolli was taught that heart cells do n't regenerate , and that any cells which die from loss of oxygen during a heart attack are lost forever . But the lesson never quite sunk in . Pacemaker pioneer now lives with one . `` That theory always struck me as odd , '' Bolli says now . `` Why would nature demand so much of a single cell , when that same cell must beat 70 times a minute throughout your life ? That seems like an unreasonable demand . '' Was it possible that new heart cells are constantly born ? And could the process be helped along to assist sick patients ? For about a decade , scientists have experimented with the use of stem cells to try and repair the heart , mostly in animals and mostly using stem cells derived from bone marrow . In 2009 , Bolli was ready to launch the SCIPIO trial ( Cardiac Stem Cells in Patients with Cardiomyopathy ) . Stem cells were taken from patients with severe heart failure and multiplied in a laboratory run by Dr. Piero Anversa at Brigham & Women 's Hospital in Boston . A few months later , each patient was re-infused with a million of his or her own stem cells . The results were dramatic . Patients saw scar tissue replaced by working heart muscle and a significant improvement in their hearts ' ability to pump blood . While the numbers are small , other studies have found similarly encouraging results . Bolli has refined his procedure to make it less invasive -- stem cells can now be taken through a catheter -- and none of the patients in cardiac stem cell trials have suffered serious adverse effects . Bolli is hoping to start a larger trial by the fall of 2013 .
Dr. Roberto Bolli directs the Institute of Molecular Cardiology in Louisville . The study was published online by Nature Medicine and is available at www.nature.com/nm/journal/v5/n6/full/nm.40931.html Citation: Patients in the trial saw dramatic improvements in their organs ' abilities .