Efficacy of Antioxidant Treatment in Reducing Resistin Serum Levels: A Randomized Study

OBJECTIVES: Few in vitro studies have examined the participation of resistin, a recently discovered adipokine, in oxidative processes. We investigated whether in vivo treatment with the antioxidant vitamin C might affect resistin serum levels. DESIGN: Randomized prospective open trial. SETTING: San Giovanni Battista Hospital, Turin, Italy. PARTICIPANTS: Eighty healthy individuals. INTERVENTION: Administration of 2 g of ascorbic acid orally for 2 wk (n = 40; experimental group) or no supplementation (n = 40; control group). OUTCOME MEASURES: The primary end point was the between-group difference in the before–after change in resistin serum level after vitamin C supplementation. Secondary endpoints were the within- and between-group changes in glucose, insulin, lipid parameters, C-reactive protein fasting values, and markers of oxidative stress. RESULTS: In the experimental group, vitamin C supplementation was significantly associated with both resistin concentration reduction (from 4.3 ± 1.5 to 2.9 ± 0.8 ng/ml; 95% confidence interval [CI] −1.87, −1.03) and ascorbic acid level increase (from 9.4 ± 2.9 to 19.0 ± 5.2 mg/l; 95% CI 7.9, 11.2). In the control group, resistin levels did not change significantly (from 4.2 ± 1.0 to 4.3 ± 0.9 ng/ml; 95% CI −0.07, 0.37). The between-group differences were highly significant (p < 0.001). Vitamin C supplementation was also associated with a statistically significant reduction in nitrotyrosine level and incremental increase in reduced glutathione. In a linear regression model, within-individual changes in vitamin C concentrations were inversely correlated with changes in resistin levels in both groups (each unit increase of vitamin C corresponded to a decrease of about 0.10 units of resistin levels (95% CI 0.13, 0.08; p < 0.001). CONCLUSION: This is to our knowledge the first randomized trial in humans that has demonstrated that short-term vitamin C supplementation could significantly reduce resistin levels, independent of changes in inflammatory or metabolic variables. Future investigations of resistin participation in oxidative processes are warranted

Relative contribution of iron burden, HFE mutations and insulin resistance to fibrosis in nonalcoholic fatty liver

The mechanism(s) determining the progression from fatty liver to steatohepatitis is currently unknown. Our goal was to define the relative impact of iron overload, genetic mutations of HFE, and insulin resistance on the severity of liver fibrosis in a population of subjects with nonalcoholic fatty liver disease (NAFLD) who had low prevalence of obesity and no overt symptoms of diabetes. In a cohort of 263 prospectively enrolled patients with NAFLD, 7.4% of patients had signs of peripheral iron overload and 9% had signs of hepatic iron overload, but 21.1% had hyperferritinemia. The prevalence of C282Y and H63D HFE mutations was similar to the general population and mutations were not associated with iron overload. Although subjects were on average only moderately overweight, insulin sensitivity, measured both in the fasting state and in response to oral glucose, was lower. Univariate analysis demonstrated that the presence of severe fibrosis was independently associated with older age, female sex, overweight, aspartate/alanine aminotransferase ratio, serum ferritin level, fasting glucose and insulin levels, decreased insulin sensitivity, and with histologic features (degree of necroinflammation and steatosis). After adjustment for body mass index (BMI), age, sex, and degree of steatosis, ferritin levels (odds ratio [OR] = 1.77; 95% CI = 1.21\u2010 2.58; P = .0032) and the oral glucose insulin sensitivity (OR = 0.53; CI = 0.33\u20100.87; P = .0113) were independent predictors of severe fibrosis. In conclusion, the current study indicates that insulin resistance is a major, independent risk factor for advanced fibrosis in patients with NAFLD. Increased ferritin levels are markers of severe histologic damage, but not of iron overload. Iron burden and HFE mutations do not contribute significantly to hepatic fibrosis in the majority of patients with NAFLD

&#8220;One pot&#8221; chloroformate derivatization of erythrocyte glutathione and its gas chromatography &#8211; mass spectrometry analysis

A simple "one-pot" derivatization and liquid-liquid extraction (LLE) procedure was developed for GC-MS analysis of reduced glutathione (GSH) analysis in erythrocytes. The metabolite was extracted by 5% (w/v) TCA, the supernatant treated with ECF and ethanol-pyridine media, the derivative separated and detected by gas chromatography-mass spectrometry using a short non-polar capillary GC column at a high column-head pressure. Total analysis time was 11min. The process was optimized by a Design of Experiment. The method was validated showing a good linearity over the 25.4-813.4μM concentration range, providing satisfactory results in terms of intra-day and inter-day precision as well as an optimal accuracy. The new method was evaluated in a pilot study involving patients with severe protein malnutrition. Comparison of this group with a group of healthy subjects revealed significantly lower GSH concentrations in erythrocytes in the former, thus proving that the described GC-MS method could be employed for fast and simple GSH analysis in clinical studies

Compositional Characteristics and Antioxidant Activity of Edible Rose Flowers and Their Effect on Phenolic Urinary Excretion

Petals of edible flowers (EF) are rich in biologically active compounds with many proven benefits for human health. However, studies on the effects of EF in humans after consumption are lacking. This pilot explorative study evaluated the changes in urinary phenolic excretion in healthy volunteers to whom different doses of phenolics from edible roses (Gourmet Roses™) have been added to a meal. Rose petals were picked fresh once a week for three weeks, showing significantly increasing values of total phenolic content, total anthocyanin content, and antioxidant activity (measured as ferric reducing antioxidant power (FRAP) and as DPPH• and ABTS•+ scavenging activities) from the first to the third week. After the meal, direct associations between urinary phenolics and both the EF phenolic content and the antioxidant activity were found in a multiple regression model. These new insights on EF consumption, to be confirmed by larger trials, suggest that the urinary phenolic excretion of healthy volunteers increases with increasing rose phenolic content

Long-Term <i>N</i>-Acetylcysteine and <scp>l</scp>-Arginine Administration Reduces Endothelial Activation and Systolic Blood Pressure in Hypertensive Patients With Type 2 Diabetes

OBJECTIVE—Reactive oxygen and nitric oxide (NO) have recently been considered to be involved in the cardiovascular complications of patients with type 2 diabetes, as NO is thought to lose its beneficial physiological effects in the presence of oxygen radicals. For this reason, we tested the effects of l-arginine (ARG) and N-acetylcysteine (NAC) administration in increasing NO bioavailability by reducing free radical formation. RESEARCH DESIGN AND METHODS—A double-blind study was performed on 24 male patients with type 2 diabetes and hypertension divided into two groups of 12 patients that randomly received either an oral supplementation of placebo or NAC + ARG for 6 months. RESULTS—The NAC + ARG treatment caused a reduction of both systolic (P &lt; 0.05) and diastolic (P &lt; 0.05) mean arterial blood pressure, total cholesterol (P &lt; 0.01), LDL cholesterol (P &lt; 0.005), oxidized LDL (P &lt; 0.05), high-sensitive C-reactive protein (P &lt; 0.05), intracellular adhesion molecule (P &lt; 0.05), vascular cell adhesion molecule (P &lt; 0.01), nitrotyrosine (P &lt; 0.01), fibrinogen (P &lt; 0.01), and plasminogen activator inhibitor-1 (P &lt; 0.05), and an improvement of the intima-media thickness during endothelial postischemic vasodilation (P &lt; 0.02). HDL cholesterol increased (P &lt; 0.05). No changes in other parameters studied were observed. CONCLUSIONS—NAC + ARG administration seems to be a potential well-tolerated antiatherogenic therapy because it improves endothelial function in hypertensive patients with type 2 diabetes by improving NO bioavailability via reduction of oxidative stress and increase of NO production. Our study's results give prominence to its potential use in primary and secondary cardiovascular prevention in these patients

For this analysis, all the variables were standardized (mean/overall standard deviation)

<p><b>Copyright information:</b></p><p>Taken from "Efficacy of Antioxidant Treatment in Reducing Resistin Serum Levels: A Randomized Study"</p><p></p><p>PLoS Clinical Trials 2007;2(5):-.</p><p>Published online 4 May 2007</p><p>PMCID:PMC1865087.</p><p> © 2007 Bo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</p

Overall plot of observed (circles) and predicted values (solid line) of variation of resistin (with 95% confidence bands; dotted lines) according to the before–after change of vitamin C concentrations (end-of-study minus baseline values)

<p><b>Copyright information:</b></p><p>Taken from "Efficacy of Antioxidant Treatment in Reducing Resistin Serum Levels: A Randomized Study"</p><p>PLoS Clinical Trials 2007;2(5):-.</p><p>Published online 4 May 2007</p><p>PMCID:PMC1865087.</p><p> © 2007 Bo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</p> Solid black circles represent the experimental group; open grey circles represent the control group

Efficacy of Antioxidant Treatment in Reducing Resistin Serum Levels: A Randomized Study-0

<p><b>Copyright information:</b></p><p>Taken from "Efficacy of Antioxidant Treatment in Reducing Resistin Serum Levels: A Randomized Study"</p><p></p><p>PLoS Clinical Trials 2007;2(5):-.</p><p>Published online 4 May 2007</p><p>PMCID:PMC1865087.</p><p> © 2007 Bo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.</p