Imagine a day when human organs could be regenerated using one’s own stem cells or those donated from other adults. Scientists are making progress toward that day, and St. Louisans learned how during a recent presentation Dr. James Willerson, president and medical director of Texas Heart Institute and a prominent stem cell researcher.
Willerson led a research team that found a patient’s own bone marrow stem cells can potentially be used to repair the heart after severe heart failure. The findings (presented during the annual session of the American College of Cardiology) are from a multi-center clinical study—the largest such investigation to date of bone marrow-derived stem cells ever done in patients with severe heart failure.
Willerson’s interest in stem cell research developed from a fascination with the origins of life. “Every part of us is the product of stem cell biology,” he says. “Every organ in the body can be regenerated from stem cells, and what’s required is to use them correctly and also to understand the genetic signals that are involved in the stem cell becoming a heart muscle cell or a brain cell.”
Besides the role that stem cells play in creating specific organs and tissues, Willerson notes that we all have an internally circulating ‘rescue system’ of stem cells that stand ready to repair damaged tissues. He explains that adult stem cells, which come from bone marrow and reside in various organs, are “patrolling our bloodstream, looking for injury and waiting to be activated.”
So why don’t our bodies naturally rebuild themselves to repair diseased or damaged organs? “Unfortunately, this system doesn’t work very well when we need it the most,” Willerson says. Based on research done with stem cells in the laboratory, scientists found that our stem cells lose the ability to reproduce themselves as we age. “It’s a bit of an enigma, why we would have such an elegant and beautiful system of repair and rescue, and at the time in our lives when we need it the most it doesn’t work,” he notes.
Willerson’s stem cell research began in 2000 as a collaboration with Dr. Emerson Perin. After promising animal studies, they treated 14 patients in Rio de Janeiro who had end-stage heart failure with stem cells derived from the patients’ own bone marrow. The research team reported in 2003 that the patients experienced improved blood flow to the heart within two months of treatment and improved heart function within four months. “Some who couldn’t walk any distance before were now jogging on the beach in Rio,” Willerson says.
The team followed the Brazilian study with a similar trial involving 30 patients in Houston, Texas, with similar results. Willerson’s most recent clinical trial of 92 patients confirmed the earlier findings. Willerson says the most potential lies with stem cells harvested from younger donors’ bone marrow, and he is preparing to submit a paper based on a study of 60 heart failure patients who were treated with a single donor’s stem cells. Other researchers are testing additional types of cells, singly and in combination, in the treatment of heart disease.
Willerson says of his current research goals: “We want to transform cells to be effective new heart muscle cells; we want to work toward regenerating the whole heart with stem cells; we want to continue our clinical trials identifying the very best adult human stem cells or combinations of them in the repair of the injured human heart.”