Adult Stem Cells: A Piece of My Heart, from Cells in My Arm?
(ROCHESTER, Minn.) — ABC’s Bill Weir left his heart in Minnesota — a tiny, pulsing piece of it, anyway.
The folks at the Mayo Clinic call it “Lil’ Bill” and it lives in a comfortable Petri dish on a climate-controlled shelf deep in the bowels of the renowned hospital.
Each day it is taken out for care and feeding and very smart people carefully check to make sure it is growing bigger and stronger by the hour.
Chances are remote that Lil’ Bill will ever join its genetic brethren in my chest, but the fact that he can peer through a microscope and see his own cardiac tissue pulse at 60 beats a minute proves that we are tantalizingly close to a Holy Grail of healing, regenerative medicine.
Though Lil’ Bill acts like heart muscle, it didn’t come from his heart. It came from the skin under his arm.
Doctors have dreamed of a day when science could grow healthy spare parts in a lab for the human body. A pivotal moment in this search came in the late ’90s when the first embryonic stem cells were isolated. These cells are the biological “seeds” that divide, differentiate and grow into the myriad parts of the human body.
While it was a thrilling discovery, it was also the start of an ethical and political firestorm, since an embryo had to be destroyed in order to isolate its stem cells. In 2001, President George W. Bush signed an executive order to restrict further research.
The move forced scientists to search for other ways and in 2007, researchers in Japan and Wisconsin figured out a way to reprogram adult cells into stem cells. Word of the discovery reached Mayo, and Dr. Tim Nelson and his colleagues at the Center for Regenerative Medicine were intrigued. This could be a way to help all those kids, born with deformed hearts, who sit on transplant waiting lists at Mayo each year.
“This is one technology that allows us to understand disease,” Dr. Nelson told ABC News, “but it also allows us to dream about the day we apply that therapeutically.” And as he described his work, he made Weir a tantalizing offer. If he would agree to partake in their research, he said Bill Weir “could be the first person to ever see his own heart tissue beat outside his body.”
It began with a biopsy of the skin under Weir’s left bicep, all the better to hide the tiny scar. With a small round knife, Dr. Nelson dug out a pencil eraser-sized chunk of the flesh and plopped it into a jar of pink liquid. Weir flew home and they went to work, using a combination of genes to bioengineer these bits of flesh into pluripotent (“many potentials”) stem cells. At that stage, they could’ve nudged them into becoming neurons or lung cells or even parts of Weir’s eyeball, but in keeping with Dr. Nelson’s promise, the Mayo team turned them into cardiac tissue.
Months later, Weir returned for a one-of-a-kind reunion and gazing through that microscope, he could see pumping proof why this kind of medical science just won the Nobel Prize.
Dr. Nelson got most excited when he showed Weir a tiny piece of his cardiac tissue that had dramatically formed into the shape of a heart — a pumping, three-dimensional glimpse into a future when this kind of cell could theoretically be injected into a heart-attack victim or a diseased child and literally mend the person from within.
That is the hope, but while these cells could grow hearts, lungs or brains they could also grow tumors. So it could be years before the science is ready for first clinical trials on humans.
For parents of kids on the transplant list, the work cannot go fast enough.
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