Effect of lutein supplementation on visual function in nonproliferative diabetic retinopathy.

BACKGROUND AND OBJECTIVES: The purpose of this study was to determine whether supplementation with lutein improved visual function in patients with nonproliferative diabetic retinopathy (NPDR). METHODS AND STUDY DESIGN: In this randomized, double-blind, placebo-controlled trial, 31 patients with NPDR were assigned randomly to 10 mg/d of lutein or identical placebo for 36 weeks. Visual performance indices, including visual acuity (VA), contrast sensitivity (CS) and glare sensitivity (GS) at four different spatial frequencies, were measured at baseline, week 18 and 36. RESULTS: At 36 weeks, a slight improvement in VA was found in the lutein group. A significant association was observed between the changes in VA and the corresponding baseline values in treatment group (r=-0.53; p=0.04). At 36 weeks, the lutein treatment group increased CS at four spatial frequencies, and the improvement achieved statistical significance at 3 cycles/degree (p=0.02). The changes in CS at 3 cycles/degree for the lutein group was marginally significantly greater than those for the placebo group (p=0.09). There was also a slight increase in GS in the lutein group up to week 36, however, no significant changes were found over time in any cycles/degree. CONCLUSIONS: In patients with NPDR, supplementation with lutein resulted in potential improvements in CS at low spatial frequency. Further studies are required to determine the possibility that such intervention could be used as an adjunct therapy to prevent vision loss in diabetic patients.

Protective effects of selenium on oxidative damage and oxidative stress related gene expression in rat liver under chronic poisoning of arsenic.

Arsenic (As) is a toxic metalloid existing widely in the environment, and chronic exposure to it through contaminated drinking water has become a global problem of public health. The present study focused on the protective effects of selenium on oxidative damage of chronic arsenic poisoning in rat liver. Rats were divided into four groups at random and given designed treatments for 20 weeks. The oxidative damage of liver tissue was evaluated by lipid peroxidation and antioxidant enzymes. Oxidative stress related genes were detected to reflect the liver stress state at the molecular level. Compared to the control and Na2SeO3 groups, the MDA content in liver tissue was decreased and the activities of antioxidant enzymes were increased in the Na2SeO3 intervention group. The mRNA levels of SOD1, CAT, GPx and Txnrd1 were increased significantly (P<0.05) in the combined Na2SeO3+NaAsO2 treatment group. The expressions of HSP70 and HO-1 were significantly (P<0.05) increased in the NaAsO2 group and reduced in the combined treatment group. The results indicate that long-term intake of NaAsO2 causes oxidative damage in the rat liver, and Na2SeO3 protects liver cells by adjusting the expression of oxidative stress related genes to improve the activities of antioxidant enzymes.