Ascorbic acid partly antagonizes resveratrol mediated heme oxygenase-1 but not paraoxonase-1 induction in cultured hepatocytes - role of the redox-regulated transcription factor Nrf2

<p>Abstract</p> <p>Background</p> <p>Both resveratrol and vitamin C (ascorbic acid) are frequently used in complementary and alternative medicine. However, little is known about the underlying mechanisms for potential health benefits of resveratrol and its interactions with ascorbic acid.</p> <p>Methods</p> <p>The antioxidant enzymes heme oxygenase-1 and paraoxonase-1 were analysed for their mRNA and protein levels in HUH7 liver cells treated with 10 and 25 μmol/l resveratrol in the absence and presence of 100 and 1000 μmol/l ascorbic acid. Additionally the transactivation of the transcription factor Nrf2 and paraoxonase-1 were determined by reporter gene assays.</p> <p>Results</p> <p>Here, we demonstrate that resveratrol induces the antioxidant enzymes heme oxygenase-1 and paraoxonase-1 in cultured hepatocytes. Heme oxygenase-1 induction by resveratrol was accompanied by an increase in Nrf2 transactivation. Resveratrol mediated Nrf2 transactivation as well as heme oxygenase-1 induction were partly antagonized by 1000 μmol/l ascorbic acid.</p> <p>Conclusions</p> <p>Unlike heme oxygenase-1 (which is highly regulated by Nrf2) paraoxonase-1 (which exhibits fewer ARE/Nrf2 binding sites in its promoter) induction by resveratrol was not counteracted by ascorbic acid. Addition of resveratrol to the cell culture medium produced relatively low levels of hydrogen peroxide which may be a positive hormetic redox-signal for Nrf2 dependent gene expression thereby driving heme oxygenase-1 induction. However, high concentrations of ascorbic acid manifold increased hydrogen peroxide production in the cell culture medium which may be a stress signal thereby disrupting the Nrf2 signalling pathway.</p

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Double-Blind Placebo-Controlled Randomized Clinical Trial of Neurofeedback for Attention-Deficit/Hyperactivity Disorder With 13-Month Follow-up

Objective: To determine whether theta/beta-ratio (TBR) electroencephalographic biofeedback (neurofeedback [NF]) has a specific effect on attention-deficit/hyperactivity disorder (ADHD) beyond nonspecific benefit. Method: In a 2-site double-blind randomized clinical trial, 144 children aged 7 to 10 years with rigorously diagnosed moderate/severe ADHD and theta/beta-ratio (TBR) ≥4.5 were randomized 3:2 to deliberate TBR downtraining versus a control of equal duration, intensity, and appearance. Two early dropouts left 142 children for modified intent-to-treat analysis. The control used prerecorded electroencephalograms with the participant's artifacts superimposed. Treatment was programmed via Internet by an off-site statistician-guided co-investigator. Fidelity was 98.7% by trainers/therapists and 93.2% by NF expert monitor. The primary outcome was parent- and teacher-rated inattention; analysis was mixed-effects regression. Because the expense and effort of NF can be justified only by enduring benefit, follow-ups were integrated. Results: Blinding was excellent. Although both groups showed significant improvement (p <.001, d = 1.5) in parent/teacher-rated inattention from baseline to treatment end and 13-month follow-up, NF was not significantly superior to the control condition at either time point on this primary outcome (d = 0.01, p =.965 at treatment end; d = 0.23, p =.412 at 13-month follow-up). Responders (Clinical Global Impression−Improvement [CGI-I] = 1−2) were 61% of NF and 54% of controls (p =.36). Adverse events were distributed proportionally between treatments. The 13-month follow-up found nonsignificant improvement from treatment end for NF (d = 0.1), with mild deterioration for controls (d = −0.07). NF required significantly less medication at follow-up (p =.012). Conclusion: This study does not support a specific effect of deliberate TBR NF at either treatment end or 13-month follow-up. Participants will be reassessed at 25-month follow-up. Clinical trial registration information: Double-Blind 2-Site Randomized Clinical Trial of Neurofeedback for ADHD; https://clinicaltrials.gov/; NCT02251743