16 May 2007

Nerve Cells Escape from Flatland--Bask in 3-D Luxury!

When scientists finally got around to culturing nerve cells in 3-D, like natural neural networks, they discovered that the cells behaved much differently, genetically, than nerve cells grown on flat 2-D cultures.
For more than 100 years, scientists have grown human cells in flat dishes. In these 2-D glass incubators, better known as petri dishes, cells stick to the bottom and spread out as they multiply. But in the body, cells don’t grow that way. They are suspended in fluids and gels and surrounded by other cells. And these cells aren’t stuck; they move.

As a result, some scientists suspect that hothouse cells do not behave like in vivo varieties. This means that the critical functions scientists are trying to understand by studying these cells – from the proliferation of cancer to the bacterial assault by antibiotics – may play out differently. Studies indeed show differences in behavior between cells cultured in 2-D and in 3-D. Cells cultured in 3-D, for example, grow faster.

....Hoffman-Kim and researchers in her lab took a line of cancerous nerve cells and cultured them in different environments. They placed one batch of cells in standard petri dishes coated with collagen. They suspended the other batch in a thicker collagen gel. The bioengineers took great pains to be sure that this one-dimension difference was the only difference in the culture conditions. Team members even counted individuals cells as they went into the dishes to be sure that each dish contained precisely the same amount.

After a day of growth, the researchers extracted RNA from the cells and conducted a microarray analysis to determine differences in gene activity. The results: A whopping 1,766 genes responded differently, either switching on or switching off. To check their work, researchers repeated the experiments but this time produced multiple copies of eight genes specifically linked to cell growth. Those experiments confirmed the differences in gene activity.

Each generation of scientists inherits a legacy of obsolete beliefs and practices, which it will either propagate to the next generation intact, or test and discard as needed. In this case, Hoffman-Kim and her colleagues decided to test the traditional methods--so they discovered something new and exciting.

Knowing that nerve cells naturally grow in 3-D, one has to wonder what took neuroscientists so long to perform such tests on 3-D cultures. One of the many problems in science and medicine is that a talent for book work and traditional lab technique, is no guarantee of the ability to innovate and think outside the box.

Many important scientific discoveries have occurred by accident--lucky discoveries from failed or accidental experiments.

With the huge numbers of scientists currently employed in biomedical research, we expect breakthroughs to occur. But the really important breakthroughs may not come about as frequently as we expect, simply because out of all working scientists, only a relative few may be willing to question traditional theories and techniques.

That is why it is so important that debate in science not be squashed, as it currently is in climate studies.


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“During times of universal deceit, telling the truth becomes a revolutionary act” _George Orwell

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