Altered flow-mediated vasodilatation, low paraoxonase-1 activity, and abnormal high-density lipoprotein subclass distribution in Takayasu's arteritis.

Background: Takayasu's arteritis (TA) is an idiopathic chronic inflammatory disease that causes occlusion of large arteries, but little is known about whether affected patients are characterized by endothelial dysfunction, different high-density lipoproteins (HDL) subclasses and paraoxonase-1 (PON1) activity.

Methods And Results: In the present study, 30 patients with TA, 30 age- and gender-matched volunteers (controls) and 15 patients with essential hypertension were studied. Flow-mediated vasodilation (FMD) and maximal blood flow velocity, assessed in the brachial artery by high-resolution ultrasound, were significantly lower in patients. HDL subclass distribution was determined by polyacrylamide gradient gel electrophoresis. HDL-cholesterol, HDL3b subclass and PON1 activity, assessed spectrophotometrically using phenylacetate as the substrate, were also lower in patients compared with controls. In a multiple regression analysis, the use of prednisone and systolic blood pressure were independent variables that predicted the FMD.

Conclusions: A low FMD, abnormal size distribution of HDLs, and low PON1 activity are observed in TA patients. These abnormalities appear independently and constitute a cluster that may contribute to the vascular dysfunction of TA arteritis.