Effects of inflammation on plasma composition and endothelial structure and function

Changes in plasma protein composition normally associated with malnutrition, specifically hypoalbuminemia and reduced levels of tranferrin and prealbumin, usually only occur in the presence of preterminal starvation in the absence of inflammation. Thus, reduced levels of any of these proteins suggest that the inflammatory response has been activated. Inflammation also alters lipoprotein structure and function, and oxidation of low-density lipoprotein (LDL). This decreases high-density lipoprotein (HDL) levels and reduces its capacity to function as an antioxidant, and increases the levels of proteins, such as fibrinogen, associated with vascular disease. Cytokines and acute phase proteins, such as C-reactive protein (CRP), also up-regulate expression of adhesion molecules on the vascular endothelium, making them more effective targets for macrophage adhesion. Leukocyte-derived myeloperoxidase functions as an “NO oxidase” in the inflamed vasculature and contributes to decreased NO bioavailability and compromises vascular reactivity. The link between inflammation and apparent malnutrition explains the relationship between low levels of albumin, prealbumin, and transferrin with subsequent cardiovascular risk.