The ability to grow replacements for failing body parts is rapidly approaching reality at the University of Minnesota’s new Stem Cell Institute.
It was probably the best surprise Catherine Verfaillie, M.D., has ever had.
A professor in the Department of Medicine at the University of Minnesota, Verfaillie has seen plenty of unusual things in the dozen or so years she’s spent exploring the spongy marrow that fills our bones. But none beats what she and graduate student Morayma Reyes found growing in a culture dish one day in 1997.
Where they had a “planted” mesenchymal stem cells – cells found in marrow that typically give rise to bone – the researchers found not just bone cells, but cells that make up the lining of blood vessels as well. Curious, they began modifying the growing conditions – and soon found they could coax the culture into producing cartilage, heart, muscle, brain, and liver cells as well. It was as though they had stumbled upon a packet of magic seeds that, depending on where they were planted, could grow into carrots, broccoli, corn, or cabbage.
“We didn’t think it would be possible,” Verfaillie says. “Then, when it turned out what we didn’t think would be possible seemed like it actually might have been happening – then the University of Minnesota – to the forefront of one of the hottest arenas in medical research today: stem cell biology. Focused on cells that have the power to differentiate into a variety of specialized tissues, this field holds promise for developing treatments or cures for an incredible array of ills, including diabetes, heart failures, Parkinson’s disease, and paralysis.
Trip Through Time To understand stem cells, let’s take a trip back through time to when you were young – so young you were still a tiny ball of cells floating inside your mother. The cells that made up the core of that ball were stem cells. Each had the capacity to give rise to skin, kidney, lung, blood, or any of the more than 200 types of cells found in your body today.
As the stem cells divided, they began to produce specialized cells, like so many high school graduates going off to make their way in the world. Some made blood cells, others, brain cells; yet others, cells that went on to become nerves, heart, intestines, or bones.
At the same time, the stem cells lost some of their versatility. Instead of being pluripotent – able to make any kind of cell – they became multipotent – able to differentiate into a few, but not all, kinds of specialty cells. The older and more developed you got, the proportion of cells that could be just about anything became smaller.
Today, most of your cells have lost the ability to give rise to any kind of cell but the kind they are. But not all.
Bone Marrow Bonanze The first hint that adults still harbor some multipotent cells came in the 1960s, when scientists discovered that bone marrow contained something that made white blood cells, red blood cells, and platelets. That “something” turned out to be hematopoietic (“blood-forming”) stem cells.
U of M Medical School
MN Medical Foundation