Abstract
Renin angiotensin (Ang) system (RAS) activation in metabolic syndrome (MS) patients is associated with elevated uric acid (UA) levels, resulting in endothelial system dysfunction. Our previous study demonstrated that excessive UA could cause endothelial injury through the aldose reductase (AR) pathway. This study is the first to show that a high concentration of Ang II in human umbilical vein endothelial cells (HUVECs) increases reactive oxygen species (ROS) components, including O2·- and H2O2, and further aggravates endothelial system injury induced by high UA (HUA). In a MS/hyperuricemia model, nitric oxide (NO) production was decreased, followed by a decrease in total antioxidant capacity (TAC), and the concentration of the endothelial injury marker von Willebrand factor (vWF) in the serum was increased. Treatment with catalase and polyethylene glycol covalently linked to superoxide dismutase (PEG-SOD) to individually remove H2O2 and O2·- or treatment with the AR inhibitor epalrestat decreased ROS and H2O2, increased NO levels and TAC, and reduced vWF release. Taken together, these data indicate that HUA and Ang II act additively to cause endothelial dysfunction via oxidative stress, and specific elimination of O2·- and H2O2 improves endothelial function. We provide theoretical evidence to prevent or delay endothelial injury caused by metabolic diseases.
Highlights
Due to economic development and an improved standard of living, obesity in adults and children is increasing
To confirm that high concentration of UA (HUA) and Ang II cause endothelial injury, we measured nitric oxide (NO) in the cell culture medium after human umbilical vein endothelial cells (HUVECs) were treated with 600 μmol/L or 10-7 mol/L Ang II for 24 h
Compared to NO levels in the normal control, the NO level was significantly decreased in the HUA and Ang II groups (p < 0:05, Figure 1(a))
Summary
Due to economic development and an improved standard of living, obesity in adults and children is increasing. Metabolic syndrome (MS) is related to obesity, atherosclerosis, hypertension, disturbance of lipid metabolism, and insulin resistance [1]. Angiotensin (Ang) II is the most wellstudied factor related to MS. The mechanism of endothelial injury involves oxidative stress, redox signal pathway activation, and cytokine and inflammatory factor reactivation [2]. Uric acid (UA) is an antioxidant, and an increase in its levels is protective against endothelial injury [6]. Our previous study found that UA has an antioxidant capacity; a high concentration of UA (HUA) causes endothelial dysfunction [7,8,9,10,11,12]
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