The role of biglycan in the healthy and thoracic aneurysmal aorta.

The class I small leucine-rich proteoglycan biglycan is a crucial structural extracellular matrix component that interacts with a wide range of extracellular matrix molecules. In addition, biglycan is involved in sequestering growth factors such as transforming growth factor-ß and bone morphogenetic proteins and thereby regulating pathway activity. Biglycan consists of a 42-kDa core protein linked to two glycosaminoglycan side chains and both are involved in protein interactions. Biglycan is encoded by the BGN gene located on the X-chromosome and is expressed in various tissues, including vascular tissue, skin, brain, kidney, lung, the immune system, and the musculoskeletal system. Although an increasing amount of data on the biological function of biglycan in the vasculature has been produced, its role in thoracic aortic aneurysms is still not fully elucidated. This review focuses on the role of biglycan in the healthy thoracic aorta and the development of thoracic aortic aneurysm and dissections in both mice and humans.