The new study will be published online on Oct. 27 and will appear in an upcoming print issue of the journal Circulation. The study may lead to a new source of adult stem cells, which may increase potential treatment options and avoid the controversial use of fetal stem cells.
"This is the first study to show that cells in the artery wall have the potential to develop into a number of other cell types," said Dr. Linda Demer, principal investigator, Guthman Professor of Medicine and Physiology, and vice chair for cardiovascular and vascular medicine at the David Geffen School of Medicine at UCLA.
UCLA researchers also report that the artery wall cells, called calcifying vascular cells (CVC), are the only cells other than actual bone marrow stromal cells that support survival of immature (developing) blood cells. This finding may have future applications in reconstitution of bone marrow after cancer treatment.
UCLA researchers cultured bovine CVC artery wall cells in the lab to see if the cells would turn into bone, fat, cartilage, marrow and muscle cells. They checked for expression of proteins and tissue matrix characteristic of each cell type.
"We wanted to see if CVC cells would become specific cell types that actually produce their own characteristic matrix (mortar-like) substance. For example, if the cell actually produced bone mineral, it would indicate that the cell had taken on a bone identity," said first author Yin Tintut, Division of Cardiology at the David Geffen School of Medicine at UCLA.
Researchers found that CVC cells had the potential to become several cell types, including bone, cartilage, marrow stromal and muscle cells, but not adipogenic, or fat, cells. Demer suggests this indicates that the CVC cells may not have the entire range of conventional stem cells. However, this may be especially useful in cases where one would not want the stem cell turning into a fat cell -- such as in trying to regenerate cartilage.
The next step involves "assessing CVC cells' potential to follow other lineages and also testing human cells," Demer said.
Stem cells are young, uncommitted cells with the ability to regenerate more stem cells and to differentiate into a variety of cell types. Researchers can then grow cells in the lab and program them to make specific tissue that may be used to repair damaged tissues such as in reconstructive surgery.
Two institutes that are part of the National Institutes of Health funded the study: the National Heart, Lung and Blood Institute, and the National Institute of Arthritis, Musculoskeletal and Skin Diseases.
Other researchers include Zeni Alfonso from the UCLA department of urology; and Trishal Saini, Kristen Radcliff, Dr. Karol Watson and Dr. Kristina Boström from the UCLA department of medicine.