Effects of selenium supplementation on paraoxonase-1 and myeloperoxidase activity in subjects with cardiovascular disease: the Selenegene study, a double-blind randomized controlled trial

INTRODUCTION: We previously highlighted the potential link between supplementation with selenium, as an antioxidant trace element, and changes in the levels of paraoxonase (POX1) and myeloperoxidase (MPO), as an antioxidant enzyme, in patients with documented cardiovascular disease (CVD). The aim of this study was to determine the effects of selenium supplementation on POX1 and MPO activity in patients with cardiovascular diseases (CVDs). MATERIAL AND METHODS: A total of 160 eligible patients were enrolled in the study. After performing some laboratory tests, including the measurement of blood selenium, triglyceride, cholesterol, and low- and high-density lipoprotein levels, the patients received 200 mg tablets of either selenium yeast or placebo. The medicines were taken orally, once daily after a meal for 60 days. Four weeks after the initial visit, the patients were invited for a follow-up visit, and interviews and non-laboratory evaluations, similar to those performed at baseline, were repeated. Compliance of patients for using selenium and placebo was measured by telephone. Medication compliance rates were monitored by telephone. The final assessments were conducted eight weeks after the beginning of the study. RESULTS: There was no significant difference in cholesterol levels between intervention and control groups (p = 0.87). No significant changes in selenium levels were observed in either the selenium or the placebo group after the intervention (p = 0.44 and p = 0.48, respectively). The two groups had a significant difference in terms of POX1 level (p = 0.039). No such difference was present in the case of MPO levels. Moreover, comparison of the values before and after the intervention showed no significant differences in the mean levels of any of the measured parameters. CONCLUSIONS: According to the obtained results, the increased POX1 levels after selenium supplementation could be attributed to the positive effect of selenium on inhibiting lipid peroxidation as part of the complicated pathophysiology of CVD.