The Dual Role of Surfactant Protein D in Vascular Inflammation and Development of Cardiovascular Disease
Cardiovascular disease (CVD) is responsible for 31% of all global deaths. Atherosclerosis is the major cause of cardiovascular disease and is a chronic inflammatory disorder in the arteries. Atherosclerosis is characterized by the accumulation of cholesterol, extracellular matrix, and immune cells in the vascular wall. Recently, the collectin surfactant protein D (SP D) an important regulator of the pulmonary immune response, was found to be expressed in the vasculature. Several in vitro studies have examined the role of SP D in the vascular inflammation leading to atherosclerosis. These studies show that SP D plays a dual role in the development of atherosclerosis. In general, SP D shows anti inflammatory properties, and dampens local inflammation in the vessel, as well as systemic inflammation. However, SP D can also exert a pro inflammatory role, as it stimulates C C chemokine receptor 2 inflammatory blood monocytes to secrete tumor necrosis factor a and increases secretion of interferon g from natural killer cells. In vivo studies examining the role of SP D in the development of atherosclerosis agree that SP D plays a proatherogenic role, with SP D knockout mice having smaller atherosclerotic plaque areas, which might be caused by a decreased systemic inflammation. Clinical studies examining the association between SP D and cardiovascular disease have reported a positive association between circulatory SP D level, carotid intima media thickness, and coronary artery calcification. Other studies have found that circulatory SP D is correlated with increased risk of both total and cardiovascular disease mortality. Both in vitro, in vivo, and clinical studies examining the relationship between SP D and CVDs will be discussed in this review.
Front. Immunol.