Stem cells may be made to build new organs

August 30th, 2008 - 1:09 pm ICT by IANS  

Washington, Aug 30 (IANS) Patients needing organ transplants may not need donated organs any more. A kind of ‘instructor’ molecule that tells blood vessel cells to organise themselves in tubes and not in layers could be an important step towards programming stem cells into building new organs instead. “Our contribution can make it possible to create blood vessels from stem cells and to direct them to form a tube instead of a layer. Perhaps this knowledge can be transferred to the formation of other tube-like structures in the body, such as the lung and intestines,” said Lena Claesson-Welsh, who led the Uppsala University study that came up with this finding.

These results may become very useful. Today stem cells are used to create new cells, organs and even tissues, that in the future might be used to for transplantation instead of donated organs, Welsh added.

If a patient’s own stem cells are used the problem with organ rejection is avoided. But so far there has been a challenge to create three-dimensional structures from stem cells, she said.

Blood vessel cells need to form three-dimensional, tube-like structures that can transport blood. But how do blood vessel cells know they should do that?

An important part of the communication between cells and their environment is the use of proteins that bind to receptors on cell surface that receives the information.

When the receptor in turn forms a complex with other proteins, on the inside of the cell, the read-out from the DNA can be altered. The information has “arrived”.

VEGF (vascular endothelial growth factor) is a family of closely related growth factors that control blood vessel cells throughout life. Blood vessel development in the foetus as well as later in life, for example during wound healing, is regulated by VEGF.

In the present study the research group has examined how VEGF can instruct blood vessel cells to arrange themselves into a tube. The answer is that some variants of VEGF have the ability to attract another protein, an instructor molecule, which is joined together with VEGF and its receptor.

The combination of instructor molecule, VEGF and receptor results in that a specific signal is sent inside the blood vessel cells, making them form a tube. Without the instructor molecule the cells line up next to each other, in a layer.

These findings were published in the scientific journal Blood.

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