Evaluation of plasma von Willebrand factor as a biomarker for acute arterial damage in rats

Plasma von Willebrand factor (vWF) was evaluated as a potential biomarker o f acute arterial damage in rats after a vasotoxic dose of the dopaminergic vasodilator, fenoldopam (FP). Male Sprague-Dawley rats were given FP or iso tonic saline by subcutaneous injection, and plasma vWF was measured at 2, 6 , and 24 hours after challenge. Mean plasma vWF values increased in FP-trea ted rats compared to controls at 2 hours (167 vs 122%: p < 0.05) and 6 hour s postdose (172 vs 130%; p < 0.01) but were comparable to control values af ter 24 hours. Mesenteric arterial lesions were observed microscopically in all FP-treated rats 24 hours postdose but were not present in rats at 1, 2, 4, 6, Or 8 hours after FY challenge. Further, plasma vWF concentrations in creased in saline-treated rats after only the minimal perturbation of repea ted venipuncture. These results indicate an early, minimal, and transient r elease of vWF that precedes the onset of morphologically evident vascular d amage. The minimal increases in plasma VWF concentrations were of limited p redictive value, may be more reflective of an acute-phase reactant response , and were not considered a reliable biomarker of acute m-induced arterial damage in the rat.