Mimicking the environment experienced by cells in the windpipe is enough to transform stem cells into a range of different lung cells. Such "physical" techniques could be used to create specialised tissues when growth factors alone aren't enough.
Lindsey Van Haute of the Free University of Brussels (VUB) in Belgium and colleagues spread human embryonic stem cells onto a porous membrane. The cells were fed from beneath by nutrients and from above by a fluid that encouraged them to multiply. Removing two chemicals from the growth fluid kickstarted differentiation.
Four days later, the team removed the fluid covering the cells, leaving them open to the air while still being sustained and supported from below, as they would be in the trachea. After 24 days the cells had developed surface proteins that identified them as specific types of lung cell, including alveolar cells, which allow the exchange of gases, and cilia, which expel bacteria and dirt.
Physical influence
"Our study proves differentiation into lung cells is influenced by physical forces," says Van Haute. Previously, stem cells have been made to differentiate into lung cells using a cocktail of different growth factors, but Haute says using physical forces might be simpler.
"Physical forces are certainly a factor in getting the lung lining to be fully functional," says Anne Bishop at Imperial College London, who has made alveolar cells from mouse stem cells using growth factors alone. "But I find it difficult to believe that raw stem cells would differentiate through to these uncommon types of cells solely in response to physical forces."
Haute's team plans to use the cells they created to study lung diseases, such as cystic fibrosis. Such cells might one day be used to treat people with damaged lung tissue, but only if the cells can be made from a person's own tissue. This could be done by converting the cells first into induced pluripotent stem cells.
Journal reference: Respiratory Research, DOI: 10.1186/1465-9921-10-105
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Have your say
The main problem I see with this being a portion of how types of cells differentiate is the simple fact that we develop lungs in the womb. This implies there are probably other ways to induce their growth, though as is stated, they are probably more complex.
Still an interesting study, and I look forward to hearing what other types of cells can be made using a physical environment.
Amniotic fluid is just like air in that it flows and presses against the stem cells. That is likely how the womb does it.
If It Done In Nature Why Is It Impossible In A Lab?
Mon Nov 09 19:20:33 GMT 2009 by Niamh O'Broin
http://New Scientist
I look forward to development of other uses of stem calls, there is so many cell based illness like M.S. stems cell could replace damaged nerves cells use of phototropism it grow eye cells, If it work with one sence why not try anything to shape and reprogram these building blocks
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