The role of paraoxonase in cancer

The paraoxonase (PON) gene family includes three proteins, PON1, PON2 and PON3. PON1 and PON3 are both associated with high-density lipoprotein (HDL) particles and exert anti-oxidant and anti-inflammatory properties. PON2 and PON3 are intracellular enzymes which modulate mitochondrial superoxide anion production and endoplasmic reticulum (ER) stress-induced apoptosis. The pleiotropic roles exerted by PONs have been mainly investigated in cardiovascular and neurodegenerative diseases. In recent years, overexpression of PON2 and PON3 has been observed in cancer cells and it has been proposed that both enzymes could be involved in tumor survival and stress resistance. Moreover, a lower activity of serum PON1 has been reported in cancer patients. This review summarizes literature data on the role of PONs in human cancers and their potential role as a target for antitumor drugs.

The role of paraoxonase in cancer

The paraoxonase (PON) gene family includes three proteins, PON1, PON2 and PON3. PON1 and PON3 are both associated with high-density lipoprotein (HDL) particles and exert anti-oxidant and anti-inflammatory properties. PON2 and PON3 are intracellular enzymes which modulate mitochondrial superoxide anion production and endoplasmic reticulum (ER) stress-induced apoptosis. The pleiotropic roles exerted by PONs have been mainly investigated in cardiovascular and neurodegenerative diseases. In recent years, overexpression of PON2 and PON3 has been observed in cancer cells and it has been proposed that both enzymes could be involved in tumor survival and stress resistance. Moreover, a lower activity of serum PON1 has been reported in cancer patients. This review summarizes literature data on the role of PONs in human cancers and their potential role as a target for antitumor drugs.

Dual signaling evoked by oxidized LDLs in vascular cells

The oxidative theory of atherosclerosis relies on the modification of low density lipoproteins (LDLs) in the vascular wall by reactive oxygen species. Modified LDLs, such as oxidized LDLs, are thought to participate in the formation of early atherosclerotic lesions (accumulation of foam cells and fatty streaks), whereas their role in advanced lesions and atherothrombotic events is more debated, because antioxidant supplementation failed to prevent coronary disease events and mortality in intervention randomized trials. As oxidized LDLs and oxidized lipids are present in atherosclerotic lesions and are able to trigger cell signaling on cultured vascular cells and macrophages, it has been proposed that they could play a role in atherogenesis and atherosclerotic vascular remodeling. Oxidized LDLs exhibit dual biological effects, which are dependent on extent of lipid peroxidation, nature of oxidized lipids (oxidized phospholipids, oxysterols, malondialdehyde, α,β-unsaturated hydroxyalkenals), concentration of oxidized LDLs and uptake by scavenger receptors (e.g. CD36, LOX-1, SRA) that signal through different transduction pathways. Moderate concentrations of mildly oxidized LDLs are proinflammatory and trigger cell migration and proliferation, whereas higher concentrations induce cell growth arrest and apoptosis. The balance between survival and apoptotic responses evoked by oxidized LDLs depends on cellular systems that regulate the cell fate, such as ceramide/sphingosine-1-phosphate rheostat, endoplasmic reticulum stress, autophagy and expression of pro/antiapoptotic proteins. In vivo, the intimal concentration of oxidized LDLs depends on the influx (hypercholesterolemia, endothelial permeability), residence time and lipid composition of LDLs, oxidative stress intensity, induction of defense mechanisms (antioxidant systems, heat shock proteins). As a consequence, the local cellular responses to oxidized LDLs may stimulate inflammatory or anti-inflammatory pathways, angiogenic or antiangiogenic responses, survival or apoptosis, thereby contributing to plaque growth, instability, complication (intraplaque hemorrhage, proteolysis, calcification, apoptosis) and rupture. Finally, these dual properties suggest that oxLDLs could be implicated at each step of atherosclerosis development, from early fatty streaks to advanced lesions, depending on the nature and concentration of their oxidized lipid content.

Impact of Statin Therapy on Plasma MMP-3, MMP-9, and TIMP-1 Concentrations: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

Tissue inhibitors of metalloproteinases (TIMPs) and matrix metalloproteinases (MMPs) are associated with the development of atherosclerosis and cardiovascular disease. Statin therapy has been shown to modulate MMPs and TIMP-1 levels, but clinical findings have not been conclusive. This study aimed to systematically review the clinical findings on the impact of statin therapy on plasma MMP-9, MMP-3, and TIMP-1 levels and calculate an effect size for the mentioned effect through a meta-analysis of available data. A total of 10 eligible studies with 11 treatment arms were included in the meta-analysis. Statin therapy had no significant effect on plasma MMP-9 (standardized mean difference [SMD]: −0.23, 95% confidence interval [CI]: −0.69 to 0.24, P = .345) nor MMP-3 concentrations (SMD: −0.004, 95% CI: −0.60 to 0.59, P = .990). However, meta-analysis demonstrated that statin therapy significantly decreases plasma TIMP-1 levels (SMD: −0.30, 95% CI: −0.56 to −0.03, P = .029). Random-effects meta-regression indicated that neither treatment duration nor changes in low-density lipoprotein cholesterol levels are associated with changes in plasma MMP-9 levels following statin therapy. The results of the present meta-analysis suggested a significant reduction in plasma concentrations of TIMP-1, but not MMP-9 and MMP-3, following statin therapy.

Adacolumn Granulocyte-Apheresis for Alcoholic Hepatitis: Preliminary Study

INTRODUCTION

Alcoholic hepatitis (AH) is an acute-on-chronic inflammatory response affecting the liver. It has been recognized that white blood cells (WBCs) are involved in the pathogenesis and in the prognosis of AH. The aim of study was to use Adacolumn, which can selectively adsorb myeloid linage leucocytes (granulocytes and monocytes/macrophages) from the blood in the column and improve the clinical status of patients.

MATERIALS

Six patients with a diagnosis of AH were treated with Adacolumn granulocyte-apheresis therapy.

INCLUSION CRITERIA

patients not responders to corticosteroids therapy with Maddrey Discriminant Function (MDF) >32 and MELD score 20-26. The patients underwent five 1-hour sessions for 5 consecutive days with a follow-up at 28 days. The column was placed in an extracorporeal setting with a perfusion rate of 30 mL/min and a duration of 60 minutes. Liver parameters, WBC count, proinflammatory cytokines, coagulation, and predictive scores were valued before and after the cycle of apheresis treatment.

RESULTS

After 5 days, the findings showed a significant improvement of WBC count (P < .014) and cytokines such as interleukin (IL)-6 (P < .019), tumor necrosis factor α (TNFα) (P < .02), and IL-8 (P < .029). The results probably determined a reduction of aspartate transaminase (AST; P < .02) and alanine transaminase (ALT; P < .011), although we did not observe a significant improve in bilirubin, prothrombin time (PT), and Maddrey score. The improvement of MELD score, depending on an improvement of international normalized ratio for administration of plasma, was not considered. At day 28 of follow-up, PT, IL-6, TNFα, AST and ALT results significantly improved.

CONCLUSIONS

The Adacolumn apheresis was safe and was able to determine an improvement of clinical status of patients with reduction of inflammatory markers. More patients are needed to validate these results.

Effect of extended-release niacin on plasma lipoprotein(a) levels: A systematic review and meta-analysis of randomized placebo-controlled trials

AIM

Lipoprotein(a) (Lp(a)) is a proatherogenic and prothrombotic lipoprotein. Our aim was to quantify the extended-release nicotinic acid Lp(a) reducing effect with a meta-analysis of the available randomized clinical trials.

METHODS

A meta-analysis and random-effects meta-regression were performed on data pooled from 14 randomized placebo-controlled clinical trials published between 1998 and 2015, comprising 17 treatment arms, which included 9013 subjects, with 5362 in the niacin arm.

RESULTS

The impact of ER niacin on plasma Lp(a) concentrations was reported in 17 treatment arms. Meta-analysis suggested a significant reduction of Lp(a) levels following ER niacin treatment (weighted mean difference - WMD: -22.90%, 95% CI: -27.32, -18.48, p<0.001). Results also remained similar when the meta-analysis was repeated with standardized mean difference as summary statistic (WMD: -0.66, 95% CI: -0.82, -0.50, p<0.001). When the studies were categorized according to the administered dose, there was a comparable effect between the subsets of studies with administered doses of <2000mg/day (WMD: -21.85%, 95% CI: -30.61, -13.10, p<0.001) and ≥2000mg/day (WMD: -23.21%, 95% CI: -28.41, -18.01, p<0.001). The results of the random-effects meta-regression did not suggest any significant association between the changes in plasma concentrations of Lp(a) with dose (slope: -0.0001; 95% CI: -0.01, 0.01; p=0.983), treatment duration (slope: -0.40; 95% CI: -0.97, 0.17; p=0.166), and percentage change in plasma HDL-C concentrations (slope: 0.44; 95% CI: -0.48, 1.36; p=0.350).

CONCLUSION

In this meta-analysis of randomized placebo-controlled clinical trials, treatment with nicotinic acid was associated with a significant reduction in Lp(a) levels.

Increased levels of lipid hydroperoxides in plasma of patients with multiple sclerosis: a relationship with paraoxonase activity

Paraoxonase, an enzyme associated with high density lipoproteins (HDL), plays an important role in the anti-oxidant and anti-inflammatory properties exerted by HDL. Increasing evidence supports a role of free radicals and oxidative stress in the inflammatory processes and in the pathogenesis of multiple sclerosis (MS). The aim of this study was to further investigate the relationship between oxidative damage and MS; therefore we compared the paraoxonase activity and levels of cholesteryl ester hydroperoxides (CE-OOH), as marker of lipid peroxidation, in plasma isolated from healthy subjects (n=89) and from MS patients (n=24) in the early stage disability (EDSSB<3.5). Our results demonstrated for the first time that the activity of paraoxonase in the plasma of MS subjects was significantly lower with respect to controls (p<0.001). Moreover, our results showed a significant increase in the levels of CE-OOH in plasma from MS subjects (p<0.001). CE-OOH are biologically active substances derived from the oxidation of cholesteryl ester localized in the hydrophobic core of plasma lipoproteins (HDL, LDL). Therefore, our study demonstrates alterations of lipoprotein peroxidation in MS and provides further evidence that oxidative stress and impairment of the anti-oxidant system may play a role in MS.

Higher Levels of Oxidized Low Density Lipoproteins in Alzheimer's Disease Patients: Roles for Platelet Activating Factor Acetyl Hydrolase and Paraoxonase-1

Alzheimer's disease (AD) is associated with oxidative damage of low density lipoproteins (ox-LDL). In order to investigate whether higher levels of ox-LDL are related to alterations of the activity of enzymes involved in lipid metabolism, we studied the activity of paraoxonase-1 (PON1) and platelet activating factor acetylhydrolase (PAF-AH) in AD patients and the relationship between biochemical markers and severity of the disease. Levels of ox-LDL, PON1 (paraoxonase, arylesterase, and lactonase activities), and PAF-AH activity were evaluated in plasma from 49 patients affected by AD and from 34 control subjects matched for gender and age. Our results demonstrated alterations in the activities of PON1 and PAF-AH in AD patients compared to controls and showed, for the first time, a relationship between the activities of these enzymes, ox-LDL levels, and severity of the disease. A significant negative correlation was observed between the ratio PON1/PAF-AH and ox-LDL. Whatever the causes that contribute to a systemic oxidative stress in AD, our results have shown that AD patients exhibit higher PAF-AH activity than control subjects and higher ox-LDL. This phenomenon, in combination with diminished PON1 in these patients and, consequently, the relatively lower ratio PON1/PAF-AH activity, could contribute to inflammation and oxidative stress of plasma lipoproteins.

Polyphenol content and glycemic load of pasta enriched with Faba bean flour

Background: Legumes contain elevated levels of health functional components. The objective of the present paper was to evaluate the nutritional properties and the post-prandial glycaemic responses of pasta obtained using 35% Vicia Faba (VF) bean flour, which is an important source of fiber and phytochemical compounds. Results: Protein and fiber content were higher in VF pasta compared with durum wheat semolina (DWS) pasta. The total antioxidant activity against peroxyl radicals evaluated by oxygen radical absorbance capacity (ORAC) assay was also observed in VF pasta. The comparison of post-prandial increase of glucose after VF intake or DWS demonstrated significant differences and VF pasta exhibited a lower glycemic index value, a lower glycemic load and higher glycemic profile compared with DWS pasta.Conclusion: The results suggest that enrichment with 35% Vicia faba bean has potential health benefits and that VF flour can be used as an ingredient to prepare added-value products. Keywords: Glycemic Index; Glycemic load; Glycemic Profile; polyphenols, flavonoids; diabetes 

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.

Statin therapy and plasma free fatty acids: a systematic review and meta-analysis of controlled clinical trials

AIM

The aim of this meta-analysis was to evaluate the effect of statin therapy on plasma FFA concentrations in a systematic review and meta-analysis of controlled clinical trials.

METHODS

PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from inception to February 16 2015) to identify controlled trials evaluating the impact of statins on plasma FFA concentrations. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderators.

RESULTS

Meta-analysis of data from 14 treatment arms indicated a significant reduction in plasma FFA concentrations following treatment with statins (weighted mean difference (WMD) -19.42%, 95% CI -23.19, --15.64, P < 0.001). Subgroup analysis confirmed the significance of the effect with both atorvastatin (WMD -20.56%, 95% CI -24.51, -16.61, P < 0.01) and simvastatin (WMD -18.05%, 95% CI -28.12, -7.99, P < 0.001). Changes in plasma FFA concentrations were independent of treatment duration (slope -0.10, 95% CI -0.30, 0.11, P = 0.354) and magnitude of reduction in plasma low density lipoprotein cholesterol concentrations (slope 0.55, 95% CI -0.17, 1.27, P = 0.133) by statins.

CONCLUSIONS

The results of the present study suggest that statin therapy may lower plasma FFA concentrations. The cardiovascular and metabolic significance of this finding requires further investigation.