Cell-Building Discovery Could Reduce Need for Some Animal Research

Biomedical engineers, using a three-dimensional (3D) Petri dish they invented, have successfully built complex-shaped microtissues by assembling small building blocks of living cell clusters. This new development should help advance the field of tissue engineering and could reduce the need for some animal research.

The Brown University (Providence, RI, USA) team, led by Brown professor Dr. Jeffrey Morgan, successfully used clusters of cells to build microtissues of more complex shapes. Such a finding, detailed in the March 1, 2009, issue of Biotechnology and Bioengineering and posted at the end of January 2009 on the journal's Website, has enormous implications for basic cell biology, drug discovery and tissue research, according to Dr. Morgan.

Because the tissues Dr. Morgan's team created in the laboratory are more like natural tissue, they can be constructed to have complicated lace-like patterns similar to a vasculature, the arrangement of blood vessels in the body or in an organ. According to Dr. Morgan, that added complexity could ultimately reduce the need to use animals in specific kinds of research. "There is a need for...tissue models that more closely mimic natural tissue already inside the body in terms of function and architecture,” said Dr. Morgan, a Brown professor of medical science and engineering. "This shows we can control the size, shape, and position of cells within these 3D structures.”

But according to Dr. Morgan, this development also makes a significant contribution to the field of tissue engineering and regenerative medicine. "We think this is one step toward using building blocks to build complex-shaped tissues that might one day be transplanted,” he said.

The new finding builds on earlier research by Dr. Morgan and a team of Brown students, which appeared in September 2007 in the journal Tissue Engineering. The earlier study highlighted the invention of a 3D Petri dish about the size of a peanut-butter cup and made of agarose, a complex carbohydrate derived from seaweed with the consistency of Jell-O (a gelatin dessert). Dr. Morgan and students in his lab developed the dish, creating a product where cells do not adhere to the surface. Instead, the cells self-assemble naturally and form "microtissues.”

For the new study, Dr. Morgan and coworkers made 3D microtissues in one 3D Petri dish, harvested these living building blocks and then added them to more complex 3D molds shaped either like a honeycomb, with holes, or a donut with a hole in the middle. Those skin cells fused with liver cells in the more complex molds and formed even larger microstructures. Researchers found that the molds helped control the shape of the final microtissue. They also found that they could control the rate of fusion of the cells by aging them for a longer or shorter time before they were harvested. The longer the wait, Dr. Morgan discovered, the slower the process.

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