RESUMEN
BACKGROUND: Increased generation of reactive oxygen and nitrogen species in chronic kidney disease (CKD) patients leads to increased oxidative stress. The antioxidant capacity of folic acid has been shown to scavenge radicals efficiently. OBJECTIVE: The current study was carried out to examine the effects of folic acid treatment on biochemical and oxidative stress biomarkers in patients in different stages of CKD. METHODS: This was a randomized, non-blinded, clinical trial that assessed the effects of 3 months of treatment with 5 mg of folic acid daily or no treatment in 113 outpatients within CKD stages 3a and 3b. At the end of the intervention, we analyzed the data of 66 patients treated with folic acid and 47 in the control group. Serum homocysteine levels and biochemical and oxidative/nitrosative stress biomarkers were analyzed in all patients. RESULTS: In most patients, folic acid treatment normalized homocysteine levels and increased antioxidant enzyme activity (paraoxonase 1) and decreased sulfhydryl (SH) groups. In addition, oxidative biomarkers (products of nitric oxide and lipid hydroperoxide) were significantly lower post-treatment compared to baseline in the active intervention group. In the no active intervention group, no statistically significant effects were found on the oxidative and biochemical biomarkers. CONCLUSION: Folic acid treatment in stages 3a-4 CKD patients effectively ameliorated their hyperhomocysteinemia and increased the activity of antioxidant enzymes, as well as decreased the levels of pro-oxidant biomarkers in stage G3a and G3b CKD patients. Folic acid treatment attenuated oxidative/nitrosative stress and may be considered as a possible strategy to improve redox status and diminish the damages associated with oxidative/nitrosative stress in CKD patients. Further studies are needed to confirm these findings. Clinical Trials Registration No.: This study is registered in the Brazilian Record of Clinical Trials (ReBEC), under reference RBR-2bfthr.
