lunes, 14 de julio de 2014

Stem cells self-organize with help from geometry


Human stem cells can form into organs, blood and brains, given a little help from chemicals and geometry. The black core, blue middle layer and red outer region represent different groups of cells. 
(Photo : The Rockefeller University)

Stem cells are unique in their ability to develop into various types of cells. Around a week after conception, embryonic cells begin to differentiate into different forms, including muscles, liver and brain cells. These changes come as a result of chemical clues from neighboring cells. 

As the zygote and embryos develop, these form into layers, in a process called gastrulation. Cells on the inside of the developing body start forming into brains and skin, while those on the outside form the organs, blood and muscles of the body. 

Regenerative medicine could be developed from cells still capable of differentiation. This could allow the development of a new generation of treatments for injury. 

Human beings use around 200 varieties of body cells. Researchers have attempted for years to teach adult cells to develop into different forms using chemicals. So far, those attempts have met with limited success. Usually, cells develop into random specific forms, without any relation between neighbors. Researchers found cells are responsive to lessons in geometry. 

"Understanding what happens in this moment, when individual members of this mass of embryonic stem cells begin to specialize for the very first time and organize themselves into layers, will be a key to harnessing the promise of regenerative medicine. It brings us closer to the possibility of replacement organs grown in petri dishes and wounds that can be swiftly healed," Ali Brivanlou of The Rockefeller University, said

The study used human stem cells that were confined within tiny round etchings on glass plates. These micropatterns were created using a chemical process. When chemicals to spur layer formation were applied to the cells, gastrulation began. Control groups of stem cells not confined in the micropatterns failed to form into layers. 

Brivanlou and his team found specific chemical signals from stem cells that encourage other cells to develop into differing parts. This allows molecular biologists to investigate the process as it occurs, something that was never before possible. 

"We can now follow individual cells in real time in order to find out what makes them specialize, and we can begin to ask questions about the underlying genetics of this process," Aryeh Warmflash, post-doctorate research on the project, stated in a press release. 

By altering the shapes of these micropatterns, researchers hope they might be able to direct the development of the cells. This could have an important impact on medical research, as healthcare researchers could develop extremely pure samples of any body tissue for testing in the laboratory. 

Research into the role of geometry in the development of stem cells was published in the journal Nature Methods.

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