Abnormal antioxidant vitamin and carotenoid status in chronic renal failure

摘要

Oxidative modification of plasma lipoproteins increases their atherogenicity. Nutritive antioxid-ants, including carotenoids, can prevent such lipoperoxidation and may protect against atherosclerosis. Plasma retinol, ascorbate, α-tocopherol and four carotenoids (lutein, lycopene, α-carotene and β-carotene) were measured using HPLC in 45 patients with chronic renal failure (CRF) and in 21 controls. Plasma retinol was significantly increased in patients with CRF (conservative therapy mean of 3.7 μmol/l vs. 1.9 μmol/l; p < 0.001). Plasma lycopene was significantly lower in patients with CRF (healthy mean 0.44 μmol/l vs. conservative therapy mean 0.27 μmol/l and haemodialysis mean of 0.17 μmol/l; p < 0.001), a finding that persisted even after adjusting for plasma cholesterol. Low circulating antioxidant lycopene levels may contribute to an already impaired antioxidant defence system in patients with CRF. The process of haemodialysis further compromises antioxidant defences, principally by removing water-soluble ascorbate and urate, but does not appear to affect circulating carotenoid concentrations.