There’s good news and bad news about adult stem cells. The good news is that human trials are officially here for adult stem cell research. As of April 1, 2009, the first stroke patient was treated with his own stem cells. The bad news is that even if his treatment proves to be successful, researchers will still be prompted to run Phase II trials and Phase III trials to determine long-term safety. It could be another 10 years before stem cell therapies are FDA-approved for the masses. Even so, the portent for this relatively new field of medicine is rather exciting.

There are some advantages to using adult stem cells over embryo-derived stem cells. For one, adult cells are easier to harvest, as they can come from skin, muscle, bone marrow and fat. Often those treated with their own stem cells will not suffer immune system rejection. It’s also easier to encourage these already specialized cells to differentiate the way the scientists want them to, which is impressive considering they’re still not 100% sure what causes a cell to become a certain organ or tissue. Lastly, donated adult stemcells clear up the stem cell controversy surrounding the destruction of human embryos in the name of science.

Mice are not people. We know this. Even so, it’s hard not be excited that the first mouse has successfully regrown muscles and regenerated damaged tissue thanks to adult stem cells. Researchers from the University of New South Wales say the mice were given a gene making them resistant to chemotherapy, which clears out damaged cells and encourages new stem cells to take hold. “What has been the realm of science fiction is looking more and more like the medicine of the future,” said Peter Gunning, one of the study’s co-authors.

While the promise of stem cell therapies is a beacon of hope for many patients, there are some disadvantages to using adult stem cells. It can be difficult to get mass quantities of adult cells and the cells scientists do get normally do not live as long in cultures, as do the fetal stem cells. Previously, it was believed that adult stem cells were not as flexible as embryonic cells and were difficult to reprogram to differentiate into other tissue types, although recent research refutes that claim.