How the spleen filters blood
Red blood cells must be small and flexible enough to squeeze through the tiniest capillaries of the body, where they deliver oxygen to surrounding cells. In the late 1960s, scientists proposed that the minute dimensions of these capillaries, which are less than 4 micrometers in diameter, are responsible for defining the size and shape of red blood cells. However, a new study led by MIT researchers reveals that these blood cell traits are actually determined by the smallest opening in the spleen. This narrow passage, known as the interendothelial slit, imposes a more stringent “physical fitness test” that all blood cells must pass before continuing to circulate through the body. “We have presented results showing that the spleen is the main organ that defines the shape of the circulating red blood cells,” says Ming Dao, a principal research scientist in MIT’s Department of Materials Science and Engineering. The findings could help scientists to...