Bu showed Action News Jax stem cells that were reprogrammed genetically and showed those neurons firing, which resembles what you’d see in the human brain. Stem cell production has long been a labor-intensive process in which researchers cultivate hundreds of tissue-culture flasks over the course of months to produce enough cells for a few patients. However, the cells are needed on a large scale, such as for a recent Mayo Clinic clinical study that found infusions of stem cells to be safe for patients who have undergone lung transplants.