RESUMO
BACKGROUND: N-3 Fatty acids reduce the risk of cardiovascular disease. Previous studies have shown that they may reduce inflammation, oxidative stress, and fat mass in patients with type 2 diabetes, but the results are inconclusive, due, in part, to type of omega-3 fatty acids used. The aim of this study was to determine the effects of pure eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), the two major omega-3 fatty acids, on inflammation, oxidative stress, and fat mass in patients with type 2 diabetes. METHODS: Sixty patients with DM-II were randomly allocated to receive daily either ~1 gr EPA or ~1 gr DHA, or a canola oil as placebo for 12 weeks in a randomized triple-blind, placebo-controlled trial. Serum MDA, CRP, body weight, BMI, and fat mass were measured at baseline and after intervention. RESULTS: Forty-five patients with a mean (±SD) age of 54.9 ± 8.2 years with BMI of 27.6 ± 4.1 kg/m(2) and fasting blood glucose 96.0 ± 16.2 mg/dl completed the intervention. Neither EPA nor DHA had significant effects on serum FBS, C-reactive protein, body weight, BMI, and fat mass after intervention (P > 0.05). In addition, while MDA increased 18% in the placebo group (P = 0.009), it did not change in the EPA or DHA group (P > 0.05). CONCLUSIONS: Twelve weeks of supplementation with 1gr/d EPA or DHA prevent increasing oxidative stress without changing marker of inflammation. This study is the first report demonstrating that neither EPA nor DHA have effects on body fat mass in type 2 diabetic patients.
RESUMO
The expression of ferroportin1 (FPN1) in reticuloendothelial macrophages supports the hypothesis that this iron-export protein participates in iron recycling from senescent erythrocytes. To gain insight into FPN1's role in macrophage iron metabolism, we examined the effect of iron status and erythrophagocytosis on FPN1 expression in J774 macrophages. Northern analysis indicated that FPN1 mRNA levels decreased with iron depletion and increased on iron loading. The iron-induced induction of FPN1 mRNA was blocked by actinomycin D, suggesting that transcriptional control was responsible for this effect. After erythrophagocytosis, FPN1 mRNA levels were also up-regulated, increasing 8-fold after 4 hours and returning to basal levels by 16 hours. Western analysis indicated corresponding increases in FPN1 protein levels, with maximal induction after 10 hours. Iron chelation suppressed FPN1 mRNA and protein induction after erythrophagocytosis, suggesting that FPN1 induction results from erythrocyte-derived iron. Comparative Northern analyses of iron-related genes after erythrophagocytosis revealed a 16-fold increase in FPN1 levels after 3 hours, a 10-fold increase in heme oxygenase-1 (HO-1) after 3 hours, a 2-fold increase in natural resistance macrophage-associated protein 1 (Nramp1) levels after 6 hours, but no change in divalent metal ion transporter 1 (DMT1) levels. The rapid and strong induction of FPN1 expression after erythrophagocytosis suggests that FPN1 plays a role in iron recycling.
