Another of the numerous different efforts to build blood vessels from a patient's own cells: "Researchers have grown small blood vessels in a lab using stem cells from fat gathered through liposuction. Such cultured blood vessels might someday play a role in transplant operations, including heart bypass surgery. ... Many more steps are involved before heart surgery patients can benefit from this technique. ... First, we will need to make a fully functional vessel. Ours works, but does not yet achieve physiological mechanical properties. [Then] we will need to show that stem cells obtained from old, sick people can also be used to make a functional vessel and that this works in an animal model. ... All in all, [we] are still five to 10 years away from seeing this being tested in people. ... For the study, researchers using liposuction extracted adult stem cells from fat and turned them into smooth muscle cells. Adult stem cells are considered to be undifferentiated, which means they hold the potential to morph into specialized cell types. ... The extracted cells were 'seeded' onto a very thin collagen membrane. As they multiplied, researchers rolled them into tubes with the diameter of small blood vessels (3 millimeters). In three to four weeks, they were able to grow usable blood vessels."