Adult stem cells help build human blood vessels in engineered tissues

by Sharon Parmet
Jalees Rehman, associate professor of cardiology and pharmacology. Credit: Roberta Dupuis-Devlin/UIC Photo Services

(Medical Xpress)—Researchers at the University of Illinois at Chicago have identified a protein expressed by human bone marrow stem cells that guides and stimulates the formation of blood vessels.

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

"Some actually have multiple jobs," says Dr. Jalees Rehman, associate professor of cardiology and pharmacology at the UIC College of Medicine and lead author of the paper. For example, stem cells in the , he said, differentiate into bone or cartilage, but also have a secondary role in helping to support other cells in the bone marrow.

Rehman and his colleagues, 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 that line blood vessels, the stem cells elongated to form scaffolds and the endothelial cells organized around them to form tubes.

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

When the cell mixtures were implanted into mice, blood vessels formed that were able to support the flow of blood. To find out how the stem cells were helping promote blood vessel formation, the researchers looked at which genes were being expressed when the stem cells and endothelial cells were combined.

This video is not supported by your browser at this time.

They 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.

"This means that not all stem cells are created alike in terms of their SLIT3 production and their ability to encourage ," Rehman said. "While using a patient's own stem cells for making blood vessels is ideal because it eliminates the problem of immune rejection, it might be a good idea to test a patient's stem cells first to make sure they are good producers of SLIT3. If they aren't, the engineered vessels may not thrive, or even fail to grow."

Mesenchymal stem cell injections are currently being evaluated in clinical trials to see if they can help grow and improve heart function in patients who have suffered heart attacks. So far, the benefits of stem cell injection have been modest, Rehman said.

"Evaluating the gene and protein signatures of stem cells from each patient may allow for a more individualized approach, so that every patient receives mesenchymal stem cells that are most likely to promote blood vessel growth and cardiac repair. Hopefully, this will substantially increase the efficacy of stem cell treatments for heart patients."

Related Stories

Packaging stem cells in capsules for heart therapy

Oct 11, 2013

Stem cell therapy for heart disease is happening. Around the world, thousands of heart disease patients have been treated in clinical studies with some form of bone marrow cells or stem cells.

Tracking nanodiamond-tagged stem cells

Aug 05, 2013

A method that is used to track the fate of a single stem cell within mouse lung tissue is reported in a study published online this week in Nature Nanotechnology. The method may offer insights into the factors that determ ...

Recommended for you

Cellular protein may be key to longevity

12 hours ago

Researchers have found that levels of a regulatory protein called ATF4, and the corresponding levels of the molecules whose expression it controls, are elevated in the livers of mice exposed to multiple interventions ...

Gut bacteria tire out T cells

15 hours ago

Leaky intestines may cripple bacteria-fighting immune cells in patients with a rare hereditary disease, according to a study by researchers in Lausanne, Switzerland. The study, published in The Journal of Experimental Me ...

T-bet tackles hepatitis

15 hours ago

A single protein may tip the balance between ridding the body of a dangerous virus and enduring life-long chronic infection, according to a report appearing in The Journal of Experimental Medicine.

User comments