For decades, scientists have used a technique called confocal microscopy to look at the distribution of proteins within a cell. But in a study published recently in Arteriosclerosis, Thrombosis and Vascular Biology, researchers used the technique in a new way: to investigate how those proteins form structures between cells.
"These are some of the first views of the skeleton of the blood vessel," says Gerald Meininger, a vascular physiology researcher from the University of Missouri–Columbia. Previous studies told scientists which proteins were used to build a blood vessel wall, but not how they were arranged in three-dimensional space.
To create the image above, Meininger and his colleague Michael Hill used fluorescent tags to label different components of an arteriole wall; cells are labeled in green, whereas elastin—a stretchy protein that holds the vascular cells together—is labeled in red. By taking a series of images with a confocal microscope, which relies on point illumination to eliminate out-of-focus areas, the researchers were able to construct a 3-D view of the blood vessel's architecture.
Using similar techniques, Hill and Meininger have already found that the elastin structure of a blood vessel wall differs between body parts and changes as an organism ages. The researchers hope that their tool will improve the understanding of how structural proteins change when people develop high blood pressure or cardiovascular disease and that, one day, it will lead to new therapeutic devices.
"In the past people thought that proteins like elastin were nothing more than a support medium for vascular cells," Hill says. "But we're starting to realize that blood vessels are much more complex than a group of cells, and that the protein environment plays an important role in helping those cells to function."