Arterial stiffening has long been considered a major risk factor for cardiovascular disease. Keeping arteries soft and supple might reduce disease risk, but the mechanisms of how arteries stave off hardening has remained elusive. Researchers from the Perelman School of Medicine, University of Pennsylvania, Wistar Institute, and The Children’s Hospital of Philadelphia have discovered that the protein apolipoprotein E (apoE) plays a major role in maintaining arterial softness by suppressing production of the extracellular matrix, a network of connective tissue in the body. Their research appeared in the most recent issue of Cell Reports.