Researchers have found that growing muscle stem cells on a specially developed synthetic matrix that mimics the elasticity of real muscle allows the adult stem cells to maintain their self-renewing properties.
Adult stem cells already exist in the body. They are important in regenerating tissues like blood, muscles and neurons in the brain. But scientists have struggled to produce them in quantities needed for therapies because the cells differentiate and lose their “stemness” as soon as they’re placed in a tissue culture dish.
Now, researchers at Stanford University have found a new method of growing the cells that will allow the behavior of many types of adult stem cells to be studied in culture.
“Cells don’t normally exist in contact with a rigid cell culture dish,” said Helen Blau, PhD, Professor and member of Stanford’s Institute for Stem Cell Biology and Regenerative Medicine. “They sit on soft tissue. By mimicking this environment we can really influence their function and allow them to self-renew in ways we’ve never been able to achieve before.”
Self-renewal, or the ability to become both another stem cell and a differentiating daughter cell, is a defining trait of stem cells. This ability is necessary for a small number of cells to, for example, fully reconstitute the pantheon of blood cell types necessary to regenerate a patient’s immune system after chemotherapy or to successfully contribute to the long-term generation of new, healthy muscle tissue. Until now, however, all attempts to grow these and some other adult stem cells, like blood stem cells, in culture have resulted in the cells differentiating into more specialized — but less therapeutically useful — progenitor cells. This differentiation constitutes a major obstacle to treating muscle-wasting diseases, for using cord blood or for treating blood cancers.
The researchers wondered if the way the cells are normally grown in culture could be the problem. After all, as Blau pointed out, cells are used to rubbing shoulders comfortably with their neighbors on all sides rather than being splayed out and anchored on a rigid plastic culture dish that is 100,000-fold less elastic than true muscle.