Effects of high doses of selenium on the antioxidant status after liver resection

Abstract

Introduction: Selenium (Se) levels in serum for patients with colorectal liver metastasis are significantly lower than normal. The use of standard doses of Se has no eff ect on serum concentrations of Se or the antioxidant status (AS) indicators. It is assumed that the use of high doses of Se for patients undergoing extensive liver resection can improve their condition by enhancing antioxidant protection. The objective of this study was therefore to evaluate the eff ect of high doses of selenium on AS indicators, biochemical markers of hepatic failure and treatment results. Methods: Forty patients (M:F = 18:22, mean age 56) who were due to have a liver resection for metastatic colorectal carcinoma were recruited and were randomized into two groups. Patients of group 1 (G1, n = 20) received standard perioperative therapy. Patients of group 2 (G2, n = 20) additionally received sodium selenite according to the protocol: 2 mg on the first postoperative day, 1 mg in the next 4 days. The concentration of Se in serum, biochemical parameters (total bilirubin, AST, ALT), AS (toxic metabolites of nitrogen oxide (NOx), superoxide dismutase (SOD) and malondialdehyde (MDA)) and clinical data were assessed before surgery and on the fi fth day after surgery. The significance of differences was assessed by Student's t test and the chi-square test. Results: There were no differences in the concentrations of biochemical markers of hepatic failure, duration of hospitalization, and 28-day survival after surgery. Before surgery Se levels were low (75.8 + 8.7 vs. 72.8 + 3.9). The NOx, MDA and SOD levels were elevated (respectively 35.1 + 1.2 vs. 35.2 + 1.8; 6.4 + 0.4 vs. 6.6 + 0.38; 106 + 8.7 vs. 107 + 8.8). After Se supplementation, Se levels were significantly higher in G2 compared with G1 (90.8 + 7.42 vs. 75.7 + 9.91, P <0.05). On the fi fth day the NOx, MDA and SOD levels decreased in G2 compared with G1 (respectively 29.5 + 1.2 vs. 39.3 + 2.2; 6.59 + 0.9 vs. 9.8 + 1.2; 84 + 10.1 vs. 123 + 7.7, P <0.05). In G2, postoperative encephalopathy was significantly less (P = 0.013). Conclusions: Even in the early postoperative period, administration of high doses of sodium selenite in patients with colorectal liver metastasis who underwent extensive liver resection helps to improve AS. However, a small number of observations does not allow one to assess accurately the clinical eff ect of high doses of Se for these patients