Nature publishes a retraction of two controversial stem cell papers from earlier this year.
Tag: stem cells (page 1 of 2)
These neural progenitor cells were generated by reprogramming cells from kidney tubules that were found in urine.
That’s not quite the best description of what this is. From Popular Science:
In their study, the researchers harvested kidney cells from the urine samples of three human donors and converted the cells directly to neural progenitors. Rather than using a genetically engineered virus to reprogram the cells, they used a small piece of bacterial DNA that can replicate in the cellular cytoplasm, a technique that eliminates the need to tamper directly with the chromosome (in theory, at least, this should reduce mutations) while also speeding up the entire process. After growing their progenitors into mature neurons and glial cells, the researchers transplanted the progenitors into the brains of newborn rats. A month later, the cells were still alive in the rats’ brains, though it is not yet clear that they can survive for extended periods or mesh with the brain’s wiring to become functioning parts of the neural machine.
There’s still a lot of research to be done on this method of course, but the researchers think it may provide a way to take cells gathered non-invasively and quickly and efficiently convert them into neural cells while reducing the likelihood of genetic mutations.
Stem cells have been used to grow a hormone producing thyroid. This is the first report of that gland being regenerated from stem cells. From Scientific American by way of Nature:
Costagliola and her colleagues first genetically engineered embryonic stem cells to express two proteins — NKX2-1 and PAX8 — that are expressed together only in the thyroid. When these cells were grown in Petri dishes in the presence of thyroid-stimulating hormone, they turned into thyroid cells.
Thyroid cells, however, have to be organized into a particular three-dimensional shape before they can work. They need to form small, spherical follicles containing a cavity in which iodide — a component of some hormones produced in the thyroid gland — can be concentrated before being absorbed and used for hormone synthesis.
Remarkably, the stem-cell-derived thyroid cells spontaneously grouped into follicles similar to those in an intact thyroid gland. And Costagliola and her colleagues found that the follicles were able to trap iodide and synthesize thyroid hormones. “When started the project, our hope was to get some cells that could be used to study thyroid physiology,” says Costagliola. “We never expected to get thyroid follicles.”