Blood vessels from stem cells: another success
Two types of building blocks for new blood vessels were obtained from stem cells
Nanonews Network based on Johns Hopkins University materials:
Steering Stem Cells to Become Two Different Building Blocks for New Blood VesselsGrowing blood vessels in the laboratory is a difficult task, but a group of bioengineers from Johns Hopkins University managed to solve the main problem:
they achieved the formation of two different types of tissues from stem cells, which are necessary for the formation of the smallest venous and arterial networks.
What allowed the researchers to achieve such success is described in detail in an article published in the journal Cardiovascular Research (Derivation and maturation of synthetic and contractile vascular smooth muscle cells from human pluripotent stem cells). This work is very important, since the transplantation of a network of new vessels grown in the laboratory can bring great benefits to patients with circulatory system damage – the result of cardiovascular diseases, diabetes and other diseases.
"Our long–term goal is to give doctors a new tool for treating patients who have problems with the vessels that supply their body with blood," says Sharon Gerecht, PhD, associate professor of the Department of Chemical and Biomolecular Technology, who led the research group. "Finding how to make stem cells become the most important building blocks for creating these blood networks is an important stage of work."
Sharon Gerecht's group focused their attention on smooth muscle cells located in the walls of blood vessels. Scientists know 2 types of such cells: synthetic smooth muscle cells migrating within the surrounding tissue, continuing to divide and supporting newly formed blood vessels; contractile cells of vascular smooth muscles remaining in place, stabilizing the growth of new vessels and helping them maintain optimal blood pressure.
To obtain smooth muscle cells, Dr. Gerecht and her colleagues conducted experiments on stem cells. They used both embryonic and induced pluripotent stem cells – mature differentiated cells genetically reprogrammed into an earlier state and possessing almost all the differentiation potential of embryonic stem cells.
In one of the earlier studies, Dr. Gerecht and her colleagues managed to induce the differentiation of stem cells into tissue close to vascular smooth muscle tissue, but still functionally different from it. In their new experiments, the researchers added growth factors and serum taken in various concentrations to stem cells.
"When we added large amounts of growth factors and serum, the stem cells turned into synthetic smooth muscle cells," explains Dr. Gerecht. "And when significantly fewer of these substances were added, they became contractile smooth muscle cells."
Two types of vascular smooth muscle cells perform different functions. Contractile cells (contractile VSMCs) cover a healthy vessel, supporting it and providing stability. Synthetic, including migrating, cells (synthetic VSMCs) are engaged in the restoration of a damaged vessel. (Illustration by Maureen Wanjare)The ability to control the type of smooth muscle cells obtained in the laboratory can play a crucial role in the growth of new vascular networks, Gerecht continues.
"When we grow the main vessels, we need contractile cells that maintain their structure and stability. But migrating synthetic cells may be more useful in working with very small blood vessels."
"There is a lot of research to be done before we can grow a full–fledged new network of blood vessels," Dr. Gerecht sums up, "but our achievements in managing the fate of stem cells seem to be a big step forward in the right direction."
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