More on Mediums

More on Mediums

I’ve been remarking for a while now on developments that show the environment in which stem cells develop has an effect upon that development. Now a research team at the University of Florida has shown that when mouse embryonic stem cells were grown on four different types of medium in culture, they differentiated into different cell types. The press release says that a cell culture molecule called laminin “activates a common developmental pathway that is crucial for the generation and survival of particular types of brain cells.” The molecule has been used as a growth medium for stem cells in many experiments in which researchers did not know they were instructing the cells to differentiate in a particular way. The research gives clues to look at other molecules in the “niche” or extracellular matrix to see how the environment signals cells to become one kind of neural cell or another.

I’d like to see this experiment duplicated with bone marrow stem cells, since they can differentiate into several different forms of normal cells. It would be interesting to know what chemical signals they are picking up from their environment, or even how much adult stem cells are affected by their environment.

Now, on one hand it seems obvious that cells are influenced by their environment—we know they can be killed or mutated by particular toxins, radiation, and so on. But killing something is very different from transforming something. And when one begins to think of a stem cell as something other than a self-contained entity, all sorts of other possibilities begin to open up.

Batten Disease Update

Batten Disease Update

Last fall the USDA approved a human trial using stem cells in the brains of children with Batten disease, an invariably fatal disorder which can cause blindness and the loss of motor skills and speech on the way to dying. It’s caused by the lack of an enzyme which protects against a build-up of lipofuscin in the brain; as the lipofuscin accumulates, it kills brain cells. Now Nature is reporting that a mouse experiment has shown some success: mice treated with human neural stem cells which produce the necessary enzyme lived 322 instead of 25 days compared to the control group, and they had more brain cells and lower lipofuscin levels. They also were producing some of the enzyme.

The human trials have not begun yet; after the FDA approval was granted, the experiment still had to receive approval from an ethics review board, which was granted in March.

Batten disease has to be one of the most horrific diseases out there, slowly stripping everything away from children. Anything to possibly treat this is good news.

Stem Cells into T Cells

Stem Cells into T Cells

Researchers at the UCLA AIDS Institute and the Institute for Stem Cell Biology and Medicine have shown that human embryonic stem cells can be coaxed into becoming T-cells. This is significant for AIDS research because HIV targets T-cells, which further weakens the immune system. Replacing T-cells would help keep the body’s defenses healthier. There’s a brief press release and a few news stories on this development. A HealthDay News story on Forbes reports that the cells were incubated on mouse bone marrow cells until they had differentiated into blood forming cells, then injected into a human thymus gland in a mouse, which converted the blood-forming cells into T cells. The researchers hope to be able to identify what signals converted the cells from one type into another so that they can apply that knowledge to diseases with a shortage of T-cells.

Hwang Update

Hwang Update

On July 3 (I’m behind….) Hwang Woo-suk admitted in court that he had ordered members of his research team to make it appear as though they were working with 11 stem cell lines instead of 2, according to an AP report on ABC News (US). He still denies violating a bioethics law. A Reuters story printed on ABC (Australian) goes into somewhat more detail. Hwang admitted to altering a data sheet before passing it on to an American researcher (I assume Gerald Schatten) and to the inflation of stem cell line numbers. However, he denied knowing about other fabrications in the papers made by junior researchers.