Tiziana Bacchetti

The Gluten-Free Diet: Safety and Nutritional Quality

The prevalence of Celiac Disease (CD), an autoimmune enteropathy, characterized by chronic inflammation of the intestinal mucosa, atrophy of intestinal villi and several clinical manifestations has increased in recent years. Subjects affected by CD cannot tolerate gluten protein, a mixture of storage proteins contained in several cereals (wheat, rye, barley and derivatives). Gluten free-diet remains the cornerstone treatment for celiac patients. Therefore the absence of gluten in natural and processed foods represents a key aspect of food safety of the gluten-free diet. A promising area is the use of minor or pseudo-cereals such as amaranth, buckwheat, quinoa, sorghum and teff. The paper is focused on the new definition of gluten-free products in food label, the nutritional properties of the gluten-free cereals and their use to prevent nutritional deficiencies of celiac subjects.

Cherry Antioxidants: From Farm to Table

The dietary consumption of fruits and vegetables is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds found in vegetable products. Sweet and sour cherries contain several antioxidants and polyphenols that possess many biological activities, such as antioxidant, anticancer and anti-inflammation properties. The review describes the effect of environment and other factors (such as production, handling and storage) on the nutritional properties of cherries, with particular attention to polyphenol compounds. Moreover the health benefits of cherries and their polyphenols against human diseases such as heart disease, cancers, diabetes are reviewed.

Effect of homocysteinylation of low density lipoproteins on lipid peroxidation of human endothelial cells

Homocysteine‐thiolactone (HcyT) is a toxic product whose synthesis is directly proportional to plasma homocysteine (Hcy) levels. Previous studies demonstrated that the interaction between HcyT and low density lipoproteins (LDL) induces the formation of homocystamide‐LDL adducts (Hcy‐LDL). Structural and functional alterations of Hcy‐LDL have been described and it has been suggested that homocysteinylation could increase atherogenicity of LDL. Oxidative damage of endothelial cells (EC) is considered to be a critical aspect of the atherosclerotic process. To further investigate the molecular mechanisms involved in the atherogenicity of homocysteinylated LDL, we studied the effect of interaction between Hcy‐LDL and EC on cell oxidative damage, using human aortic endothelial cells (HAEC) as experimental model. Homocysteinylation of LDL was carried out by incubation of LDL, isolated from plasma of healthy normolipemic subjects, with HcyT (10–100 μM). In our experimental conditions, homocysteinylation treatment was not accompanied by oxidative damage of LDL. No modifications of apoprotein structure and physico‐chemical properties were observed in Hcy‐LDL with respect to control LDL (c‐LDL), as evaluated using the intrinsic fluorescence of tryptophan and the probe Laurdan incorporated in lipoproteins. Our results demonstrated that Hcy‐LDL incubated at 37°C for 3 h with HAEC, induced an oxidative damage on human EC with a significant increase of lipid hydroperoxides in cells incubated with Hcy‐LDL with respect to cell incubated with c‐LDL. The compositional changes were associated with a significant decrease viability in cells treated with Hcy‐LDL. The relationship between the levels of –SH groups of LDL and the oxidative damage of HAEC has been demonstrated. These results suggest that Hcy‐LDL exert a cytotoxic effect that is likely related to an increase in lipid peroxidation and oxidative damage of EC.

Effect of statin therapy on paraoxonase-1 status: A systematic review and meta-analysis of 25 clinical trials.

BACKGROUND Decreased activity of the enzyme paraoxonase-1 (PON1) has been demonstrated in cardiovascular diseases. Statins, the forefront of pharmacotherapy for dyslipidemia, have been shown to enhance PON1 activity but clinical findings have not been conclusive. OBJECTIVE To systematically review the clinical findings on the impact of statin therapy on PON1 status (protein concentrations and activities of paraoxonase and arylesterase) and calculate an effect size for the mentioned effects through meta-analysis of available data. METHODS Scopus and Medline databases were searched to identify clinical trials. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the one-study remove approach. Random-effects meta-regression was performed to assess the impact of potential confounders on the estimated effect sizes. RESULTS Meta-analysis suggested that statin therapy is associated with a significant elevation of PON1 paraoxonase and arylesterase activities, but not PON1 protein concentration. The PON1-enhancing effects of statins were robust in the sensitivity analyses and were independent of statin dose, treatment duration and changes in plasma low-density lipoprotein cholesterol concentration. CONCLUSION The increase of paraoxonase and arylesterase activities with statins is a pleiotropic lipid-independent clinical benefit that may partly explain the putative effects of statins in preventing cardiovascular outcomes.

Celiac Disease, Inflammation and Oxidative Damage: A Nutrigenetic Approach

Celiac disease (CD), a common heritable chronic inflammatory condition of the small intestine caused by permanent intolerance to gluten/gliadin (prolamin), is characterized by a complex interplay between genetic and environmental factors. Developments in proteomics have provided an important contribution to the understanding of the biochemical and immunological aspects of the disease and the mechanisms involved in toxicity of prolamins. It has been demonstrated that some gliadin peptides resistant to complete proteolytic digestion may directly affect intestinal cell structure and functions by modulating gene expression and oxidative stress. In recent years, the creation of the two research fields Nutrigenomics and Nutrigenetics, has enabled the elucidation of some interactions between diet, nutrients and genes. Various dietary components including long chain ω-3 fatty acids, plant flavonoids, and carotenoids have been demonstrated to modulate oxidative stress, gene expression and production of inflammatory mediators. Therefore their adoption could preserve intestinal barrier integrity, play a protective role against toxicity of gliadin peptides and have a role in nutritional therapy of celiac disease.

Reactive oxygen species plasmatic levels in ischemic stroke

Oxidative stress is probably one of the mechanisms involved in neuronal damage induced by ischemia-reperfusion, and the antioxidant activity of plasma may be an important factor providing protection from neurological damage caused by stroke-associated oxidative stress. The aim of this study was to investigate the status of oxidative stress, NO and ONOO− levels in patients with atherothrombotic and lacunar acute ischemic stroke and iNOS, eNOS and nitrotyrosine expression in the same patients. Plasma ONOO− levels were significantly higher in patients than in controls while NO decreases in patients in respect to controls. Densitometric analysis of bands indicated that iNOS and N-Tyr protein levels were significantly higher in patients in respect to controls. This study has highlighted a significant NO decrease in our patients compared with controls and this is most probably due to the increased expression of inducible NO synthase by the effect of thrombotic attack. In fact, the constitutive NO isoforms, which produce small amounts of NO, are beneficial, while activation of the inducible isoform of NO, which produces much more NO, causes injury, being its toxicity greatly enhanced by generation of peroxynitrite. The significant ONOO− increase observed in our patients, compared to controls, is most probably due to reaction of NO with O2·−. These findings suggest that free radical production and oxidative stress in ischemic stroke might have a major role in the pathogenesis of ischemic brain injury. Peroxynitrite might be the main marker of brain damage and neurological impairment in acute ischemic stroke.

HDL-paraoxonase and Membrane Lipid Peroxidation: A Comparison Between Healthy and Obese Subjects

High‐density lipoproteins (HDLs) play a key role in the protection against oxidative damage. The enzyme paraoxonase‐1 (PON1) associated at the surface of HDL modulates the antioxidant and anti‐inflammatory role of HDL. Previous studies have demonstrated a decrease of serum PON in obese patients. The aim of this study was to investigate whether modifications of PON1 activity reflect in a different ability to protect and/or repair biological membranes against oxidative damage. Thirty obese patients at different grades of obesity (BMI ranging from 30.4 to 64.0 kg/m2) and 62 age‐matched control subjects (BMI <25 kg/m2) were included in the study. The ability of HDL to protect membranes against oxidative damage was studied using erythrocyte membranes oxidized with 2,2‐azobis(2 amidinopropane)dihydrochloride (AAPH) (ox‐membrane). The membrane lipid hydroperoxide levels were evaluated after the incubation of ox‐membranes in the absence or in the presence of HDL of controls or obese patients. The results confirm that HDL exerts a protective effect against lipid peroxidation. The ability of HDL to repair erythrocyte membranes was positively correlated with HDL‐PON activity and negatively correlated with lipid hydroperoxide levels in HDL. These results suggest that PON modulates the HDL repairing ability. HDL from obese patients repaired less efficiently erythrocyte membranes against oxidative damage with respect to HDL from healthy subjects. A negative relationship has been established between BMI of obese patients and the protective effect of HDL. In conclusion, the decrease of HDL‐PON activity and the lower HDL protective action against membrane peroxidation in obese patients could contribute to accelerate the cellular oxidative damage and arteriosclerosis in obesity.

Lipid peroxidation in hemodialysis patients: effect of vitamin C supplementation.

OBJECTIVES Renal failure is associated with several metabolic disturbances and increasing evidences support a role of oxidative stress and impaired antioxidant defence in the pathologic mechanisms that may contribute to accelerated atherogenesis in these patients. Aim of the study was to further investigate the relationship between oxidative stress and chronic renal failure. DESIGN AND METHODS We compared the paraoxonase (PON1) activity, the levels of lipid hydroperoxides and AGE adducts in plasma of hemodialysis patients before and after intravenous administration of vitamin C. RESULTS An increase in lipid hydroperoxides, AGE adducts and a decrease in the activity of PON1 were observed in patients with respect to controls. The comparison before and after supplementation with vitamin C showed an increase of PON1 activity and a decrease of AGE and lipid hydroperoxides levels. CONCLUSIONS The results provide further evidence that lipid peroxidation and impairment of antioxidant system in plasma of patients may play a role in renal disease and suggest that evaluation of PON1 activity could represents an useful approach to monitor antioxidant treatment and new dialysis therapies.

Peroxidation of lipoproteins in multiple sclerosis

Human plasma low density lipoproteins (LDL) and high density lipoproteins (HDL) are involved in the transport of lipids, modulate membrane lipid composition and regulate signal transduction. HDL-like lipoproteins have been shown also in human cerebrospinal fluid and it has been hypothesized that they could have a role in lipid transport in central nervous system. After synthesis, lipoproteins are susceptible to lipid peroxidation triggered by reactive oxygen species (ROS and RNS) produced by peripheral and brain cells. Aim of the paper has been to review the scientific literature on the role of lipid peroxidation of LDL and HDL in the molecular mechanisms of multiple sclerosis (MS). Several studies have demonstrated a significant increase in lipid peroxidation products in brain, plasma and cerebrospinal fluid of MS patients. The increase of antibodies against ox-LDL in plasma and the presence of ox-LDL in demyelinating plaques in MS brain suggests that the disease is associated with oxidative damage of lipoproteins. The impairment of antioxidant systems or an increase in the production of ROS and RNS could contribute to lipoprotein peroxidation in MS. Oxidized lipoproteins show several alterations of their functions, they are neurotoxic and have pro-inflammatory properties. Therefore lipoprotein lipid peroxidation products could be involved in demyelination and axonal injury in MS.

Effect of monoclonal antibodies to PCSK9 on high‐sensitivity C‐reactive protein levels: a meta‐analysis of 16 randomized controlled treatment arms

AIMS Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are an emerging class of low-density lipoprotein cholesterol (LDL-C)-lowering agents. In spite of their known effects on lipids, the impact of these drugs on systemic inflammation is less known. We aimed to investigate the effect of PCSK9 inhibitors on high-sensitivity C-reactive protein (hs-CRP) levels through a meta-analysis of randomized controlled trials (RCTs). METHODS A systematic literature search of Medline, SCOPUS and Google Scholar was conducted up to December 2015 to identify RCTs assessing changes in hs-CRP concentrations during treatment with PCSK9 inhibitors. Quantitative data synthesis was performed using a random-effects model, with weighed mean difference (WMD) and 95% confidence interval (CI) as summary statistics. RESULTS Sixteen treatment arms, with a total of 2546 participants, were included. Random-effects meta-analysis did not show any significant effect of PCSK9 inhibitors on hs-CRP levels (WMD: 0.002 mg l(-1) , CI: -0.017, 0.021; P = 0.807; I(2) = 37.26%). This effect size was robust, not sensitive to any single study, and not affected by the type of PCSK9 inhibitor (evolocumab: WMD: 0.002 mg l(-1) , CI: -0.02, 0.02; P = 0.855; alirocumab WMD: 0.15 mg l(-1) , CI: -0.11, 0.40; P = 0.259; I(2) = 0%), or dosing frequency (biweekly: WMD: 0.13 mg l(-1) , CI: -0.20, 0.46; P = 0.433; I(2) = 55.19%; monthly: WMD: 0.003 mg l(-1) , CI: -0.01, 0.01; P = 0.59; I(2) = 0%). Random-effects meta-regression did not suggest any association of changes in hs-CRP levels with changes in plasma LDL-C concentrations (P = 0.697) or cumulative dosage of the drug (P = 0.980). CONCLUSIONS This meta-analysis of RCTs did not suggest an effect of PCSK9 inhibitors on hs-CRP concentrations.