Fenofibrate abrogates postprandial blood viscosity among hypertriglyceridemia subjects with the metabolic syndrome

Background: Elevations in blood viscosity have been implicated in the pathogenesis of microvascular disease in patients with diabetes. Recently, fenofibrate has been shown to reduce microvascular complications of diabetes. This study investigates whether fenofibrate lowers fasting and postprandial blood viscosity in patients at high risk for future onset of diabetes. Methods: Thirty-eight subjects were randomized to fenofibrate (160 mg/d) or placebo in a double-blind controlled clinical trial. A standardized oral fat load was given after a 12 h fast before administration of study medication and after 3 months following the start of therapy. Blood specimens were obtained at fasting, 3.5 h, and 8 h after the test meal. Blood viscosity was measured at 37 °C on fasting and postprandial specimens using a coaxial cylinder microviscometer. Results: Postprandial blood viscosity was reduced in fenofibrate-treated patients at low and high shear rates. In multivariate models that included conventional risk factors, absolute changes in hematocrit and fibrinogen, there were significant reductions in 8-h postprandial blood viscosity at 100 s^-1 × 0.13 mPas (95% CI: -0.23, -0.03; p = 0.0415), 10 s^-1 × 0.31 mPas (95% CI: -0.60, -0.01; p = 0.022) and at 1 s^-1 × 1.24 mPas (95% CI: -2.52, 0.05; p = 0.0083). Postprandial reductions in blood viscosity were most highly correlated with reductions in VLDL particles (range = 0.305-0.444, p = 0.066-0.018). Conclusions: Fenofibrate lowers postprandial blood viscosity at low and high shear rates, and this hemorheological effect may contribute to the observed improvement in microvascular disease in patients treated with fenofibrate.