Direct effects of C‐reactive protein on endothelial cell survival: Role of oxidative stress

Abstract

Elevated C-reactive protein (CRP) is associated with enhanced cardiovascular disease risk but the roles of CRP as a participant of the disease process have not been defined. Early endothelial cell injury and dysfunction are recognized events in cardiovascular disease but the initiating events are not well established. Here we tested the hypothesis that recombinant human CRP (rhCRP) can elicit endothelial cell toxicity in-vitro and that the cellular injury is related to intracellular oxidant stress. Human umbilical vein endothelial cells (ECs) were incubated for 48h with rhCRP, or heat denatured recombinant hdCRP (0, 2.5, 5, 10, 20 μg/ml). Intracellular evidence of reactive oxidant species was assessed using 2′,7′-dichlorofluorescin diacetate fluorescence microscopy and cell survival was concurrently determined. rhCRP, but not hd-CRP, caused concentration dependent increases in oxidant production and loss of cell viability (Cell kill – percent of control: 1.3%, 17.8% and 35.2%; rhCRP 2.5, 5 and 10μg/ml). These data demonstrate that rhCRP, at concentrations known to predict adverse vascular outcomes in-vivo, directly causes human endothelial cell toxicity. The ability of CRP to induce reactive oxidant species and to inhibit endothelial cell survival may represent an important mechanism that further links endothelial dysfunction to cardiovascular disease.