Blood vessels from liposuction stem cells

Adult stem cells extracted during liposuction can be used to grow new, small-diameter blood vessels for use in heart bypass surgery, U.S. researchers say. Lead author Matthias Nollert -- an associate professor at the University of Oklahoma School of Chemical, Biological and Materials Engineering, in Norman, Okla. -- said the liposuction-derived vessels, grown in a laboratory, could help solve major problems associated with grafting blood vessels from elsewhere in the body or from using artificial blood vessels that are not living tissue. In the study, adult stem cells derived from fat were turned into smooth muscle cells in the laboratory, and then "seeded" onto a very thin collagen membrane. As the stem cells multiplied, the researchers rolled them into tubes matching the diameter of small blood vessels. In three to four weeks, they grew into usable blood vessels, Nollert said. "Current small-diameter vessel grafts carry an inherent risk of clotting, being rejected or otherwise failing to function normally," Nollert said in a statement. "Our engineered blood vessels have good mechanical properties and we believe they will contract normally when exposed to hormones. They also appear to prevent the accumulation of blood platelets -- a component in blood that causes arteries to narrow." The findings were presented at the American Heart Association's Basic Cardiovascular Sciences scientific sessions in New Orleans.