Mesenchymal stem cells (MSCs) reportedly exist in a vascular niche occupying the outer adventitial layer. However, these cells have not been well characterized in vivo in medium- and large-sized arteries in humans, and their potential pathological role is unknown. 

Researchers studied stem cells from adult human vessels. The research team acquired surplus specimens from patients having cardiac and vascular surgeries and applied multiple complimentary techniques to profile these vessels and their stem cells.

Researchers identify, in situ and in vivo, adventitial CD90+ (a protein used as a marker for a variety of stem cells) and mesenchymal stem cells (MSCs) in human arteries for the first time. MSC markers including PDGFRα, CD44, CD73, and CD105 were also seen. However, unlike CD90, these additional markers were widely expressed by other cells.

They found that mesenchymal stem cells exist in the outer layer of arteries in adult humans, and appear to play a key role in mediating vascular diseases, including coronary artery disease.

"The next step is to delve more deeply into the biology of these cells, and to identify specific ways to manipulate these cells as a clinical therapeutic tool," said the senior author.

https://www.cell.com/stem-cell-reports/fulltext/S2213-6711(18)30264-9