Stem cells: Chemistry paves way toward promising therapies

SAN FRANCISCO, Sept. 14 -- Chemists are developing new insights and techniques in an effort to expand the therapeutic potential of stem cells, which includes possible treatments for Parkinson's disease, diabetes, spinal cord injury and other devastating conditions. The American Chemical Society will explore some of these latest developments, including new findings on the transformation potential of adult stem cells, during a special symposium, "Emerging Technologies: Stem Cells," on Thursday, Sept. 14, in San Francisco during the Society's 232nd national meeting. All papers in this symposium, which begins at 1:30 p.m., will be presented at the Hilton San Francisco, Yosemite B.

Shown below are selected papers from this symposium:

Adult stem cells show wider potential than previously thought -- Embryonic stem cells are the most versatile stem cells, capable of being transformed into any other cell type, depending on their desired therapeutic use.

Now, researchers at Northwestern University have found new evidence that hematopoietic stem cells, a type of adult stem cell derived from the bone marrow that gives rise to blood cells, is capable of undergoing more diverse transformations than previously thought and could be transformed into a wide variety of tissue types, not just blood cells.

In recent laboratory tests, human megakaryocytes (bone marrow cells that produce blood platelets that are responsible for blood clotting) derived from adult hematopoietic stem cells were, for the first time, reprogrammed into neutrophil-like cells similar to the white blood cells that are responsible for fighting infections, according to study leader E. Terry Papoutsakis, Ph.D., a chemical engineer at the University.

Insights from this study could help guide similar adult stem cell transformations in other cell types in the future, he says. (BIOT 459, Thursday, Sept. 14, 1:30 p.m.)

Elasticity of tissue environment plays role in determining stem cell growth --Researchers at the University of Pennsylvania have shown that the elasticity of a stem cell's environment is a major determinant of what type of tissue the stem cell becomes. In laboratory tests, Dennis Discher, Ph.D., and Adam Engler, Ph.D., grew mesenchymal stem cells (derived from adult bone marrow) in polymer hydrogels with either soft, medium or rigid elasticity.

Based on resulting cell shapes as well as messenger RNA and protein markers, stem cells grown in softer environments -- such as brain tissue -- tended to produce nerve-like cells; those grown in environments with medium elasticity -- similar to muscle -- produced muscle-like cells; and stem cells grown in more rigid environments -- like bone -- produced bone-like cells.

The study provides new clues on how chemical and mechanical factors interact to influence stem cell growth, the researchers say. (BIOT 463, Thursday, Sept. 14, 3:10 p.m.)

'Stretched' stem cells have potential to be transformed into blood vessel cells -- Scientists have searched for years for a renewable cell source to craft blood vessels that can be used for heart bypass surgery and perform more like natural arteries.

Now, researchers at the University of California, Berkeley, have shown that mesenchymal stem cells from adult bone marrow can be repeatedly and mechanically stretched -- in a manner similar to a taffy pull -- into patterns that could potentially transform them into smooth muscle cells similar to blood vessel tissue.

These newly-formed smooth muscle cells, which can expand and contract, could be used as a component of a tissue-engineered graft that may provide superior performance over conventional grafts that are used for bypass surgery, says study leader Kyle Kurpinkski, a doctoral candidate in the University's Department of Bioengineering. (BIOT 464, Thursday, Sept. 14, 3:30 p.m.)