Stem cell surprises

Scientists are discovering many new sources of stem cells for research. Here are some of the more surprising:

BRAIN CELLS FROM URINE:

Cells from the lining of the kidney are routinely shed in urine. Scientists at China's Guangzhou Institutes of Bio-medicine and Health and their colleagues recently used a special brew of transcription factors to reprogram these cells into neural progenitor cells. They went on to successfully derive human brain cells that could survive in newborn rat brains.

3-D PRINTED STEM CELLS:

3-D printers lay down thin layers of material much like ordinary printers, except they deposit layer upon layer to create 3-D objects. A team of researchers at Heriot-Watt University and Roslin Cellab in Scotland recently showed they could print using inks containing human embryonic stem cells, which stayed alive after printing and could develop into different types of cells. Bio-engineers are exploring 3-D printing as a way of creating tissues and organs for transplant.

STEM CELLS FROM CADAVERS:

Last year, researchers at the Pasteur Institute in Paris and colleagues discovered that stem cells can remain alive in human corpses for at least 17 days after death. They kept cadavers at 4C to avoid decomposition and these stem cells, which normally give rise to skeletal muscle, survived without oxygen. The cells had extraordinarily reduced metabolic activity when discovered, marking the first time scientists have found that stem cells were capable of such dormancy. Another team of scientists at NIH and the Lieber Institute for Brain Development in Baltimore discovered that living cells from the scalps and brain linings of human corpses could be transformed into stem cells. Specifically, fibroblasts, the most common cells of connective tissue in animals, could be collected from cadavers and reprogrammed into induced pluripotent stem cells, which could then develop into a multitude of cell types, including neurons