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Data about the impacts of hemodialysis on antioxidant status and markers of oxidative stress are controversial, probably due to the use of different methodological approaches. The aim of this study was to assess the changes in the oxidative damage markers and antioxidant enzymes, and the serum antioxidant capacity by using in vitro model systems of free radical generation before and after one hemodialysis session. Blood samples were collected from 40 patients with kidney failure before and after hemodialysis. In pre- and post-hemodialysis serum samples, concentrations of biomarkers of oxidative damage and the activities of antioxidant enzymes were measured, as well as the in vitro antioxidant potential. The high concentrations of oxidative stress markers in serum of kidney failure patients were decreased after one hemodialysis session. In pre-hemodialysis, low activities of antioxidant enzymes were observed, including paraoxonase-1, however paraoxonase-1 activity was partially recovered after hemodialysis. Crocin bleaching and radical scavenging assays showed that serum antioxidant potential was decreased after hemodialysis. Although one hemodialysis session increased paraoxonase-1 activity and decreased oxidative stress markers, it caused a decrease in the serum antioxidant potential. Future research is needed to prospect strategies to mitigate the impacts of oxidative stress in the scenario of hemodialysis repetitions.

Background: Combination of current antidiabetic agents with natural antioxidants to manage diabetes mellitus and its complications has appeared as an emerging trend. Curcumin, a yellow pigment isolated from Curcuma longa rhizomes, has gained attention due to its beneficial effects in controlling the disturbances observed in diabetes mellitus. The purpose of this study was to investigate if yoghurt enriched with curcumin and metformin, individually or as mixtures, ameliorates physiometabolic parameters, glycoxidative stress biomarkers, and paraoxonase 1 (PON 1) activity in diabetic rats., Methods: Streptozotocin-diabetic rats (6-week-old Wistar rats) were treated for 30 days with curcumin and metformin, isolated or as mixtures in yoghurt (10 rats/group). After treatments, the plasma levels of glucose, triacylglycerol, cholesterol, thiobarbituric acid reactive substances (TBARS, a biomarker of lipid oxidation), fluorescent advanced glycation end products (AGEs), and the activity of PON 1, an antioxidant enzyme were assessed. Data were analyzed using one-way analysis of variance (ANOVA) followed by Student-Newman-Keuls test., Results: Treatment of diabetic rats with curcumin or metformin alone decreased the plasma levels of glucose, triacylglycerol, cholesterol, TBARS, and fluorescent AGEs, as well as increased the activity of PON 1. The combination of metformin with curcumin further decreased dyslipidemia and TBARS levels in diabetic rats, indicating synergy, and maintained the high levels of PON 1., Conclusion: These findings indicated that curcumin combined with metformin may act synergistically on dyslipidemia and oxidative stress, as well as increased PON 1 levels. Therefore, it might be a promising strategy for combating diabetic complications, mainly the cardiovascular events., Competing Interests: The authors declare that they have no competing interests.