Blood vessels take damage when plagued by peripheral artery disease, and cells injected as an attempt to heal blood vessels often don’t survive long enough to take effect. Today, a new scientific endeavor offers new stem cells and a new protective gel to create long-lasting cells to successfully heal blood vessels and prevent future heart disease.
Peripheral artery disease (PAD) is characterized by a narrowing of the peripheral arteries, like those heading to the legs, stomach, arms, and head, although PAD in the legs is most common form of the disease. PAD, often accompanied by cramping, pain, and tiredness while walking, like other heart diseases, is caused by atherosclerosis.
In the new study from the Emory University School of Medicine, study leader Young-sup Yoon, MD, PhD, and his team aspired to begin with stem cells derived from the person with the disease, ultimately creating personalized induced pluripotent stem cells (iPSCs) that would become endothelial cells. These are the cells that make up the tissue lining the walls of blood vessels.
Yoon also developed a gel that surrounds and supports endothelial cells, which are eventually injected into the body to heal damaged blood vessels. With the supportive gel, the new cells can survive more than a record-setting 10 months .
"When cells are implanted on their own, many of them die quickly, and the main therapeutic benefits are from growth factors they secrete,"Yoon explained. "When these endothelial cells are delivered in a gel, they are protected. It takes several weeks for most of them to migrate to vessels and incorporate into them."
During past attempts to use similar types of cells to heal blood vessels, cells survived for just a few days or weeks.
How did they obtain iPSCs? Researchers were able to “reprogram” cells using the “Yamanaka factors” to become iPSCs. Yamanaka factors are a series of gene/protein pairs “highly expressed in embryonic stem cells” that “induce pluripotency.” Once they had iPSCs, they used growth factors to induce the cells’ transformation into endothelial cells, which Yoon says are “compatible with clinical applications.”
The gel supports endothelial cells as it “mimics the supportive effects of the extracellular matrix” and helps them survive oxidative stress. Also, the gel is biodegradable
Yoon and his team completed a study of the cells and the protective gel, injecting both into mice exhibiting a model of peripheral artery disease. After about a month, mice injected with gel-encapsulated endothelial cells as compared to the control group who didn’t receive treatment had the healthiest blood vessels.
Why do endothelial cells help heal blood vessels? They produce pro-angiogenic and vasculogenic growth factors, with angiogenesis being the process of building new blood vessels.
The present study was published in the journal Circulation.
Sources: Cell Research, American Heart Association, Emory Health Sciences