New protein that guides and stimulates blood vessel formation identified

Washington: Researchers have identified a protein that is expressed by human bone marrow stem cells that helps guide and stimulate the formation of blood vessels.

Their findings, which could help improve the vascularization of engineered tissues, were reported online on October 12 in the Journal of Molecular and Cellular Cardiology.

Lead author Dr. Jalees Rehman, associate professor of cardiology and pharmacology at the UIC College of Medicine, said that some stem cells actually have multiple jobs, for example, stem cells in the bone marrow differentiate into bone or cartilage, but also have a secondary role in helping to support other cells in the bone marrow.

Rehman and his team, who are developing engineered tissues for use in cardiac patients, observed that certain stem cells in bone marrow, called mesenchymal stem cells, seemed crucial for organizing other cells into functional blood vessels.

The researchers demonstrated that when they mixed mesenchymal stem cells from human bone marrow with the endothelial cells that line blood vessels, the stem cells elongated to form scaffolds and the endothelial cells organized around them to form tubes.

Rehman said that without the stem cells, the endothelial cells just sat there.

When the cell mixtures were implanted into mice, blood vessels formed, which were able to support the flow of blood.

Researchers tested two different stem cell lines from human bone marrow. One line supported the formation of blood vessel networks when it was mixed with endothelial cells, while the other cell line did not.

They analyzed the genetic signature and proteins of the respective cell lines and found that the vessel-supporting stem cell line released high levels of a blood vessel guidance molecule - SLIT3. In the mixture that didn't form blood vessels, the SLIT3 gene was hardly expressed, Rehman said.

Their findings have been published in the Journal of Molecular and Cellular Cardiology.