Redox imbalance and immune functions: opposite effects of oxidized low-density lipoproteins and N-acetylcysteine

Restoration of IL-11 and IL-15 cytokine production post calcium modulators and ROS treatment can assist viral clearance both in vitro and in vivo

Objectives

Hepatitis B virus (HBV) infection alters the cytokines production to establish persistent infection. A reversion of cytokines back to their normal state can be a promising therapeutic approach to establish an optimal host immune response.

Materials and Methods

We investigated the alteration in expression of IL-15 and IL-11 after HBV infection in vitro and in vivo in PBMCs of 63 individuals divided into various HBV-infected patient groups. The mRNA expression was evaluated post-anti-oxidant and calcium modulators treatment by Real-time qPCR.

Results

In vitro mRNA expression of both cytokines, post-infection was down-regulated considerably. Interestingly, in line with in vitro results, both cytokines' in vivo expression was intensively down-regulated in chronic HBV-infected individuals rather than healthy controls. Both cytokines' expression was up-regulated in cases of recovery compared with the inactive carriers and chronic HBV-infected individuals. IL-15 mRNA expression was significantly up-regulated in both cell lines post EGTA and Ru360 treatment while a significant increase was observed in the HepAD38 cell line with NAC and BAPTA treatment. IL-11 mRNA expression was significantly up-regulated in the HepG2 cell line after all modulator treatments, whereas in the HepAd38 cell line it was observed after BAPTA treatment. Our results thus indicate that viral infection tends to down-regulate the expression of cytokines and an in vivo up-regulation is an indication of recovery.

Conclusion

Treatment of anti-oxidants and calcium modulators has resulted in the successful restoration of these cytokines thus pointing towards the use of calcium modulators to boost natural antiviral cytokine production.

Exposure to a high dose of amoxicillin causes behavioral changes and oxidative stress in young zebrafish

Autistic spectrum disorder (ASD) is a group of early-onset neurodevelopmental disorders characterized by impaired social and communication skills. Autism is widely described as a behavioral syndrome with multiple etiologies where may exhibit neurobiological, genetic, and psychological deficits. Studies have indicated that long term use of antibiotics can alter the intestinal flora followed by neuroendocrine changes, leading to behavioral changes. Indeed, previous studies demonstrate that a high dose of amoxicillin can change behavioral parameters in murine animal models. The objective was to evaluate behavioral and oxidative stress parameters in zebrafish exposed to a high dose of amoxicillin for 7 days. Young zebrafish were exposed to a daily concentration of amoxicillin (100 mg/L) for 7 days. Subsequently, the behavioral analysis was performed, and the brain content was dissected for the evaluation of oxidative stress parameters. Zebrafish exposed to a high dose of amoxicillin showed locomotor alteration and decreased social interaction behavior. In addition, besides the significant decrease of sulfhydryl content, there was a marked decrease in catalase activity, as well as an increased superoxide dismutase activity in brain tissue. Thus, through the zebrafish model was possible to note a central effect related to the exposition of amoxicillin, the same as observed in murine models. Further, the present data reinforce the relation of the gut-brain-axis and the use of zebrafish as a useful tool to investigate new therapies for autistic traits.

Reactive oxygen species in immune cells: A new antitumor target

Immune cells have the potential to control the growth of tumor. However, this effect could be offset by immunosuppression associated with an increased production of reactive oxygen species. Multiple studies indicate that the antitumor effect of immune cells is correlated with their antioxidant capacity. This review discusses the role of reactive oxygen species in the tumor microenvironment by describing their distinct effects on different immune cells, including myeloid-derived suppressor cells, regulatory T cells, tumor-associated macrophages, cytotoxic T lymphocytes, natural killer cells, and dendritic cells. In the end, we conclude with the prospect of treatment for cancer by targeting antioxidant defense in immune cells.

Redox control of cancer cell destruction

Redox regulation has been proposed to control various aspects of carcinogenesis, cancer cell growth, metabolism, migration, invasion, metastasis and cancer vascularization. As cancer has many faces, the role of redox control in different cancers and in the numerous cancer-related processes often point in different directions. In this review, we focus on the redox control mechanisms of tumor cell destruction. The review covers the tumor-intrinsic role of oxidants derived from the reduction of oxygen and nitrogen in the control of tumor cell proliferation as well as the roles of oxidants and antioxidant systems in cancer cell death caused by traditional anticancer weapons (chemotherapeutic agents, radiotherapy, photodynamic therapy). Emphasis is also put on the role of oxidants and redox status in the outcome following interactions between cancer cells, cytotoxic lymphocytes and tumor infiltrating macrophages.

Exploring an animal model of amodiaquine-induced liver injury in rats and mice

Amodiaquine (AQ) is associated with a relatively high incidence of idiosyncratic drug-induced liver injury (IDILI) and agranulocytosis. A previous study reported that a combination of high dose AQ and glutathione (GSH) depletion led to liver injury. However, the characteristics of this toxicity were very different from AQ-induced liver injury in humans. We developed a model of AQ-induced liver injury with characteristics similar to the injury in humans by treating mice with lower doses of AQ for several weeks. In this study we found that not only did GSH depletion not increase AQ covalent binding to hepatic proteins at this lower dose, but also it paradoxically prevented the liver injury. We extended the model to rats and found AQ treatment led to a mild delayed onset liver injury that resolved despite continued treatment with AQ. Immunohistochemistry indicated the presence of Kupffer cell activation, apoptosis and hepatocyte proliferation in the liver. There was also an increase in serum IL-2, IL-5, IL-9, IL-12, MCP-1 and TGFβ, but a decrease in leptin. Coincident with the elevated serum ALT, the number of liver CD4(+) T-cells, IL-17 secreting cells and TH17/Treg cells increased at Week 3 and decreased during continued treatment. Increases in NK1.1+ cells and activated M2 macrophages were also observed during liver injury. These results suggest that the outcome of the liver injury was determined by the balance between effector and regulatory cells. Co-treatment with cyclosporin prevented AQ-induced liver injury, which supports an immune mechanism. Retinoic acid (RA), which has been reported to enhance natural killer (NK) cell activity, exacerbated AQ-induced liver injury. These results suggest that AQ-induced IDILI is immune mediated and the subsequent adaptation appears to represent immune tolerance.

Prevention and treatment of cancers by immune modulating nutrients

Epidemiological and laboratory data support the protective effects of bioactive nutrients in our diets for various diseases. Along with various factors, such as genetic history, alcohol, smoking, exercise, and dietary choices play a vital role in affecting an individual's immune responses toward a transforming cell, by either preventing or accelerating a neoplastic transformation. Ample evidence suggests that dietary nutrients control the inflammatory and protumorigenic responses in immune cells. Immunoprevention is usually associated with the modulation of immune responses that help in resolving the inflammation, thus improving clinical outcome. Various metabolic pathway-related nutrients, including glutamine, arginine, vitamins, minerals, and long-chain fatty acids, are important components of immunonutrient mixes. Epidemiological studies related to these substances have reported different results, with no or minimal effects. However, several studies suggest that these nutrients may have immune-modulating effects that may lower cancer risk. Preclinical studies submit that most of these components may provide beneficial effects. The present review discusses the available data, the immune-modulating functions of these nutrients, and how these substances could be used to study immune modulation in a neoplastic environment. Further research will help to determine whether the mechanistic signaling pathways in immune cells altered by nutrients can be exploited for cancer prevention and treatment.

Oxidative stress during erythropoietin hyporesponsiveness anemia at end stage renal disease: Molecular and biochemical studies

Inflammation and oxidative stress are two faces of one coin in end stage renal disease patients (ESRD) on maintenance hemodialysis. Their interconnection induces anemia complicated with erythropoietin hyporesponsiveness. The biochemical bases behind the resistance to erythropoietin therapy with frequent hemoglobinemia, oxidative stress and iron status have not been fully understood. Here two equal groups (40 patients each) of responders and non-responders to recombinant human erythropoietin therapy (higher than 300 IU/kg/wk of epoetin) were investigated. Hematological and biochemical analyses of collected blood and serum samples were performed along with serum electrophoretic protein footprinting. The leukocytic DNA fragmentation was used to evaluate the degree of oxidative insult. The good responders showed lower erythrocyte malondialdehyde (E-MDA) level and less DNA fragmentation of circulating leukocytes than poor responders with elevated hemoglobin, albumin, A/G ratio, total iron, and ferritin levels. Contrariwise, lower erythrocyte superoxide dismutase (E-SOD) and catalase activities in EPO poor responder group were noticed. Neither other serum constituents nor electrophoretic protein pattern showed any difference between the two groups. There were higher levels of inflammatory markers, interleukin-6 (IL6) and C-reactive protein (CRP) in EPO poor responder than good responder. The negative correlations between Hb and both IL6 and CRP levels in the present data remotely indicate a positive correlation between inflammatory markers and severity of anemia. A direct correlation between Hb and antioxidant enzymes (E-SOD and catalase) was noticed, while inverse correlation with E-MDA was recorded. The study proved that oral supplementation of vitamin C to ESRD patients might mitigate the previously elevated serum MDA level in these patients.

Intracellular redox state as target for anti-influenza therapy: are antioxidants always effective?

Influenza virus infections represent a big issue for public health since effective treatments are still lacking. In particular, the emergence of strains resistant to drugs limits the effectiveness of anti-influenza agents. For this reason, many efforts have been dedicated to the identification of new therapeutic strategies aimed at targeting the virus-host cell interactions. Oxidative stress is a characteristic of some viral infections including influenza. Because antioxidants defend cells from damage caused by reactive oxygen species induced by different stimuli including pathogens, they represent interesting molecules to fight infectious diseases. However, most of the available studies have found that these would-be panaceas could actually exacerbate the diseases they claim to prevent, and have thus revealed "the dark side" of these molecules. This review article discusses the latest opportunities and drawbacks of the antioxidants used in anti-influenza therapy and new perspectives.

Sulforaphane induces ROS mediated induction of NKG2D ligands in human cancer cell lines and enhances susceptibility to NK cell mediated lysis

AIMS

The goal of this study is to investigate the tumor cytotoxic effects of sulforaphane (SFN) and ionizing radiation (IR) as well as their ability to up-regulate natural killer group 2, member D (NKG2D) ligands and modulate the susceptibility of tumor cells to natural killer (NK) cell-mediated killing.

MAIN METHODS

Expression of MHC class I-related chain molecules A and B (MICA/MICB) and total reactive oxygen species (ROS) were assessed by flow cytometry following labeling with appropriate dyes or antibodies. NK cell cytotoxicity was determined by calcein release of target cells.

KEY FINDINGS

The expression of NKG2D ligands MICA/MICB was found to vary in all the four tumor cell lines tested (MCF7 < A549 < MDA-MB-231 < U937). Exposure of these cells to IR and SFN resulted in a differential induction of these ligands. IR induced an increase in expression of MICA/MICB in MCF7 cells and SFN induced MICA/MICB expression in A549 and MDA-MB-231 cells. This SFN induced increase in receptor expression resulted in increased susceptibility to NK cell mediated killing of tumor cells which was abrogated by blocking with anti-MICA/MICB antibody. SFN induced increase in MICA/MICB expression as well as increased susceptibility to NK cell mediated killing was abrogated by N-acetyl cysteine in A549 and MDA-MB-231 cells suggesting a ROS mediated mechanism.

SIGNIFICANCE

Our results indicate that SFN has an immunotherapeutic potential to be used in cancer therapy.

Perinatal stress, brain inflammation and risk of autism-review and proposal

BACKGROUND

Autism Spectrum Disorders (ASD) are neurodevelopmental disorders characterized by varying deficits in social interactions, communication, and learning, as well as stereotypic behaviors. Despite the significant increase in ASD, there are few if any clues for its pathogenesis, hampering early detection or treatment. Premature babies are also more vulnerable to infections and inflammation leading to neurodevelopmental problems and higher risk of developing ASD. Many autism "susceptibility" genes have been identified, but "environmental" factors appear to play a significant role. Increasing evidence suggests that there are different ASD endophenotypes.

DISCUSSION

We review relevant literature suggesting in utero inflammation can lead to preterm labor, while insufficient development of the gut-blood-brain barriers could permit exposure to potential neurotoxins. This risk apparently may increase in parents with "allergic" or autoimmune problems during gestation, or if they had been exposed to stressors. The presence of circulating auto-antibodies against fetal brain proteins in mothers is associated with higher risk of autism and suggests disruption of the blood-brain-barrier (BBB). A number of papers have reported increased brain expression or cerebrospinal fluid (CSF) levels of pro-inflammatory cytokines, especially TNF, which is preformed in mast cells. Recent evidence also indicates increased serum levels of the pro-inflammatory mast cell trigger neurotensin (NT), and of extracellular mitochondrial DNA (mtDNA), which is immunogenic. Gene mutations of phosphatase and tensin homolog (PTEN), the negative regulator of the mammalian target of rapamycin (mTOR), have been linked to higher risk of autism, but also to increased proliferation and function of mast cells.

SUMMARY

Premature birth and susceptibility genes may make infants more vulnerable to allergic, environmental, infectious, or stress-related triggers that could stimulate mast cell release of pro-inflammatory and neurotoxic molecules, thus contributing to brain inflammation and ASD pathogenesis, at least in an endophenotype of ASD patients.

Deranged bioenergetics and defective redox capacity in T lymphocytes and neutrophils are related to cellular dysfunction and increased oxidative stress in patients with active systemic lupus erythematosus

Urinary excretion of N-benzoyl-glycyl-Nε-(hexanonyl)lysine, a biomarker of oxidative stress, was higher in 26 patients with active systemic lupus erythematosus (SLE) than in 11 non-SLE patients with connective tissue diseases and in 14 healthy volunteers. We hypothesized that increased oxidative stress in active SLE might be attributable to deranged bioenergetics, defective reduction-oxidation (redox) capacity, or other factors. We demonstrated that, compared to normal cells, T lymphocytes (T) and polymorphonuclear neutrophils (PMN) of active SLE showed defective expression of facilitative glucose transporters GLUT-3 and GLUT-6, which led to increased intracellular basal lactate and decreased ATP production. In addition, the redox capacity, including intracellular GSH levels and the enzyme activity of glutathione peroxidase (GSH-Px) and γ-glutamyl-transpeptidase (GGT), was decreased in SLE-T. Compared to normal cells, SLE-PMN showed decreased intracellular GSH levels, and GGT enzyme activity was found in SLE-PMN and enhanced expression of CD53, a coprecipitating molecule for GGT. We conclude that deranged cellular bioenergetics and defective redox capacity in T and PMN are responsible for cellular immune dysfunction and are related to increased oxidative stress in active SLE patients.

Trans-plasma membrane electron transport in mammals: functional significance in health and disease

Trans-plasma membrane electron transport (t-PMET) has been established since the 1960s, but it has only been subject to more intensive research in the last decade. The discovery and characterization at the molecular level of its novel components has increased our understanding of how t-PMET regulates distinct cellular functions. This review will give an update on t-PMET, with particular emphasis on how its malfunction relates to some diseases, such as cancer, abnormal cell death, cardiovascular diseases, aging, obesity, neurodegenerative diseases, pulmonary fibrosis, asthma, and genetically linked pathologies. Understanding these relationships may provide novel therapeutic approaches for pathologies associated with unbalanced redox state.

Linkage of some trace elements, peripheral blood lymphocytes, inflammation, and oxidative stress in patients undergoing either hemodialysis or peritoneal dialysis

BACKGROUND

Changes in essential trace elements may affect the inflammatory and immunological state of patients on hemodialysis (HD) or peritoneal dialysis (PD). Therefore, we aimed to determine trace element content and markers of oxidative stress, inflammation, and immune status in HD and PD patients and to assess the relationships among these parameters.

METHODS

Patients on either HD (n = 20) or PD (n = 20) and age-, sex-, body mass index-matched healthy individuals (n = 20) were enrolled in the study. The trace elements zinc, copper, selenium, and iron; markers of oxidative stress thiobarbituric acid reactive substances (TBARS) and protein carbonyl levels; activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase; percentages of CD3 T lymphocytes and the subsets CD4 and CD8; the CD4/CD8 ratio; and C-reactive protein (CRP) were measured.

RESULTS

All dialysis patients had low levels of albumin and hemoglobin. Significantly decreased percentages of CD3 and CD4 T lymphocytes and increased levels of CRP, TBARS, and carbonyl compounds were observed in HD patients. HD patients also had elevated erythrocyte SOD, lower GPx and catalase activities, and decreased levels of Se, Zn, and Fe in comparison to PD patients and healthy subjects. In addition, CRP was positively associated with TBARS and carbonyl levels, but was significantly inversely associated with Zn and Se levels. Positive correlations were found between T lymphocyte CD3 and CD4 percentages and Zn, Se, and Fe levels.

CONCLUSIONS

There were significant decreases in T lymphocyte-related immunological regulation and increased inflammation and oxidative stress in dialysis patients. Essential trace element status was independently related to immune status, inflammation, and oxidative damage.

Effect of N-acetyl-L-cysteine on Cytokine Production by Human Peripheral Blood Mononuclear Cells

OBJECTIVES

This study investigates the in vitro effect of the antioxidant drug, N-acetyl-L-cysteine (NAC), on cytokine production by peripheral blood mononuclear cells (PBMC).

METHODS

PBMC were isolated by Ficoll-Hypaque, and stimulated with anti-CD3 antibodies, phytohaemagglutinin (PHA), lipopolysaccharide (LPS) for 24 hours in the presence or absence of 5 mM NAC. The cytokines produced were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Treatment with NAC significantly up-regulates the secretion of IL-1β, IL-5 (interleukin) and IFN-γ (interferon) and down regulates IL-10 production, after anti-CD3 or PHA (p<0.05), but not after LPS stimulation. NAC also significantly increased total IL-12 secretion after anti-CD3 (but not PHA or LPS) stimulation and IL-12p40 after anti-CD3, PHA, and LPS stimulation (p <0.05).

CONCLUSION

These results indicate that NAC up-regulated the production of pro-inflammatory cytokines, and down regulated anti-inflammatory cytokine production by PBMC, in a process which may be associated with increased levels of glutathione (GSH). Further work is required to determine whether this increase or decrease in cytokine production is due to direct effect of NAC.

Decreased serum Ou/Zn sOD in children with Autism

Aim

To assess serum Cu/Zn SOD (Superoxide Dismutase) concentration in autistic children and evaluate its possible relationship to GI Symptoms.

Subjects and Methods

Serum from 50 autistic children (31 with chronic digestive disease (most with ileo-colonic lymphoid nodular hyperplasia (LNH) and inflammation of the colorectal, small bowel and/or stomach) and 19 autistic children without GI disease), and 29 non autistic controls (20 age matched non autistic children with no GI disease and 9 age matched non autistic children with GI disease) were tested for Cu/Zn SOD using ELISAs.

Results

Serum Cu/Zn SOD levels of autistic children were significantly lower than all non autistic controls (p < 0.0001). Serum Cu/Zn SOD of autistic children with severe GI disease was significantly lower than autistic children with no GI disease (p < 0.0001), non autistic children without GI disease (<0.0001) and non autistic children with GI disease (p = 0.0003).

Discussion

These results suggest an association between Cu/Zn SOD serum levels and autism, particularly autistic children with GI disease, and that the concentration of serum Cu/Zn SOD may be a useful biomarker for autistic children with severe GI disease.

Natural killer cells, glutathione, cytokines, and innate immunity against Mycobacterium tuberculosis

It is becoming increasingly apparent that natural killer (NK) cells play a crucial role in innate defense mechanisms against Mycobacterium tuberculosis infection. Furthermore, NK cell functions are dependent on adequate levels of glutathione. In this study, we examined whether the NK cell-mediated growth control of intracellular M. tuberculosis is dependent on adequate levels of glutathione. We investigated the effects of glutathione both alone and in combination with interleukin-2 (IL-2) or IL-12 or both in modulating NK cell functions, such as cytolytic activity, activating receptor expression, induction of apoptosis, and cytokine synthesis. Our results strongly indicate that glutathione in combination with IL-2+IL-12 augments NK cell functions, leading to control M. tuberculosis infection.

NK cell apoptosis in coronary artery disease: relation to oxidative stress

OBJECTIVE

Natural killer (NK) cells, key elements in initiation and modulation of immune responses, were recently found to be reduced in coronary artery disease (CAD). To clarify mechanisms behind this reduction, we here investigated NK cell apoptosis in CAD patients. Since oxidative stress has been linked to NK cell apoptosis, we related the findings to oxidative stress in vivo and evaluated the ex vivo susceptibility of NK cells to oxidized lipids.

METHODS AND RESULTS

The number of apoptotic NK cells in peripheral blood was significantly increased in CAD patients compared to controls. Purified NK cells from CAD patients also showed a higher rate of spontaneous apoptosis ex vivo. Dose- and time-dependent effects of oxidized LDL and 7beta-hydroxycholesterol (7betaOH) on apoptosis and ROS production were determined in NK cells from blood donors. Thereafter, purified NK cells from CAD patients and healthy controls were exposed to the oxidized lipids in a paired design. NK cells from patients were more susceptible to apoptosis induced by oxidized LDL, in particular 7betaOH, compared to cells from controls. Plasma measurements of LDL protein oxidation and lipid peroxidation did not show any differences between patients and controls. On the other hand, plasma carotenoids were significantly decreased in patients and inversely correlated to NK cell apoptosis rate.

CONCLUSION

The rate of spontaneous NK cell apoptosis was increased in CAD patients. Although NK cells in CAD patients were more sensitive to oxidized lipids ex vivo, indicating a mechanism contributing to the reduced NK cell activity in CAD, the data could not verify an obvious link between NK cell apoptosis and increased oxidative stress in vivo.

Oxidative stress in autism

Autism is a severe developmental disorder with poorly understood etiology. Oxidative stress in autism has been studied at the membrane level and also by measuring products of lipid peroxidation, detoxifying agents (such as glutathione), and antioxidants involved in the defense system against reactive oxygen species (ROS). Lipid peroxidation markers are elevated in autism, indicating that oxidative stress is increased in this disease. Levels of major antioxidant serum proteins, namely transferrin (iron-binding protein) and ceruloplasmin (copper-binding protein), are decreased in children with autism. There is a positive correlation between reduced levels of these proteins and loss of previously acquired language skills in children with autism. The alterations in ceruloplasmin and transferrin levels may lead to abnormal iron and copper metabolism in autism. The membrane phospholipids, the prime target of ROS, are also altered in autism. The levels of phosphatidylethanolamine (PE) are decreased, and phosphatidylserine (PS) levels are increased in the erythrocyte membrane of children with autism as compared to their unaffected siblings. Several studies have suggested alterations in the activities of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, and catalase in autism. Additionally, altered glutathione levels and homocysteine/methionine metabolism, increased inflammation, excitotoxicity, as well as mitochondrial and immune dysfunction have been suggested in autism. Furthermore, environmental and genetic factors may increase vulnerability to oxidative stress in autism. Taken together, these studies suggest increased oxidative stress in autism that may contribute to the development of this disease. A mechanism linking oxidative stress with membrane lipid abnormalities, inflammation, aberrant immune response, impaired energy metabolism and excitotoxicity, leading to clinical symptoms and pathogenesis of autism is proposed.

Low plasma levels of oxygenated carotenoids in patients with coronary artery disease

BACKGROUND AND AIMS

Low circulating levels of carotenoids have been associated with cardiovascular disease. The distribution of different carotenoids in blood may have an impact on the cardioprotective capacity. The aim of the present study was to determine the plasma levels of 6 major carotenoids in patients with coronary artery disease (CAD) and relate the findings to clinical, metabolic and immune parameters.

METHODS AND RESULTS

Plasma levels of oxygenated carotenoids (lutein, zeaxanthin, beta-cryptoxanthin) and hydrocarbon carotenoids (alpha-carotene, beta-carotene, lycopene) were determined in 39 patients with acute coronary syndrome, 50 patients with stable CAD and 50 controls. Serological assays for inflammatory activity and flow cytometrical analysis of lymphocyte subsets were performed. Both patient groups had significantly lower plasma levels of oxygenated carotenoids, in particular lutein+zeaxanthin, compared to controls. Low levels of oxygenated carotenoids were associated with smoking, high body mass index (BMI), low high density lipoprotein (HDL) cholesterol and, to a minor degree, inflammatory activity. Plasma levels of lutein+zeaxanthin were independently associated with the proportions of natural killer (NK) cells, but not with other lymphocytes, in blood.

CONCLUSION

Among carotenoids, lutein+zeaxanthin and beta-cryptoxanthin were significantly reduced in CAD patients independent of clinical setting. The levels were correlated to a number of established cardiovascular risk factors. In addition, the relationship between NK cells and lutein+zeaxanthin may indicate a particular role for certain carotenoids in the immunological scenario of CAD.

Mildly oxidized low-density lipoprotein inhibits the in vitro induction of the specific antibody response to Candida albicans

Oxidized low-density lipoprotein plays a critical role in the pathogenesis of atherosclerosis and exerts pleiotropic effects on various cellular functions. The present study was designed to evaluate the effects of mildly oxidized LDL (mLDL) on the induction and regulation of an in vitro specific antibody response. We found that mLDL significantly inhibited the induction of the anti-Candida albicans antibody response by human peripheral blood mononuclear cells (PBMC). mLDL-induced down-regulation of antibody production was abrogated by blocking the major receptors that bind and internalize modified LDL. In the mLDL-treated C. albicans-stimulated PBMC cultures an early increase in IL-1beta production was observed and the addition of anti-IL-1beta antibody abrogated the mLDL-induced inhibitory effect. Moreover, the addition of IL-1beta to the cultures inhibited the induction of the specific antibody response, similar to mLDL. On the other hand, mLDL up-regulated PWM-induced polyclonal immunoglobulin (Ig) production. In the same cultures IgM anti-mLDL was found. These results indicate that the up-regulation of IL-1beta production induced by mLDL may be involved in the hindering of B cell function, i.e., specific antibody production. This could be relevant in the pathogenesis of inflammatory diseases such as atherosclerosis.

The −174G/C polymorphism of IL-6 is useful to screen old subjects at risk for atherosclerosis or to reach successful ageing

High levels of IL-6 are coupled with impaired immune efficiency, morbidity and mortality in ageing. Elderly men with GG (C-) genotype in -174 locus of IL-6 promoter are disadvantaged for longevity due to higher IL-6 than CG or CC (C+) carriers. As IL-6 increases in atherosclerosis, the study of the polymorphism of IL-6 may be a useful tool in identifying old subjects at risk for atherosclerosis. Thus, we divided old men into C+ and C- genotypes. Natural killer (NK) cell cytotoxicity, IL-6, IL-10, TNF-alpha, MTmRNA and zinc ion bioavailability were also evaluated and compared with nonagenarians and old patients affected by carotid stenosis. Old C- patients display, other than elevated IL-6, higher IL-10, TNF-alpha and MTmRNA coupled with impaired NK cell cytotoxicity and lower zinc ion bioavailability than C+ patients. The same trend is observed in old subjects with C- phenotype. Nonagenarians with C+ genotype show less inflammation, low MTmRNA, satisfactory NK cell cytotoxicity and good zinc bioavailability than long-living individuals with C- genotype. A higher degree of bilateral carotid stenosis is observed in C- patients than in C+ patients (88 vs 52%). Therefore, C- genotype is coupled with chronic inflammation, impaired immune efficiency, low zinc ion bioavailability and high MTmRNA. As such, C- genotype is a risk factor for the appearance of severe atherosclerosis. Thus, the polymorphism of IL-6, together with the analysis of zinc turnover and immune parameters, is of a great clinical relevance in order to genetically identify old subjects at risk in developing severe atherosclerosis and, at the same time, to predict subjects predestined to successful ageing. As a consequence, more convenient therapies may be prepared for a complete recovery.