Polymorphisms in manganese superoxide dismutase and catalase genes: functional study in Hong Kong Chinese asthma patients

Korean Red Ginseng Ameliorates Allergic Asthma through Reduction of Lung Inflammation and Oxidation

Six-year-old red ginseng, which is processed from the whole ginseng root via steaming and drying, has been shown to have preventive effects such as antioxidative, anti-inflammatory, and immunomodulatory. In this study, we evaluated the therapeutic effects of Korean red ginseng (KRG) against ovalbumin (OVA)-induced allergic asthma and the underlying mechanisms involved. We injected 20 µg of OVA on days 0 and 14, and mice were challenged with aerosolized OVA via a nebulizer for 1 h on days 21, 22, and 23. KRG was administered at 100 and 300 mg/kg from days 18 to 23. The KRG-treated mice showed significant reductions in their airway hyperresponsiveness, production of reactive oxygen species (ROS), and the number of inflammatory cells compared with the OVA-treated mice. The levels of type 2 cytokines in the bronchoalveolar lavage fluid and expression of OVA-specific immunoglobulin E in the serum, which were elevated in the OVA group, were reduced in the KRG-treated groups. The pro-inflammatory factors, inducible nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells, were downregulated by the KRG administration in a dose-dependent manner. KRG effectively suppressed the inflammatory response by inhibiting ROS production. Our results suggest that KRG may have the potential to alleviate asthma.

Nutrigenetics of antioxidant enzymes and micronutrient needs in the context of viral infections

Sustaining adequate nutritional needs of a population is a challenging task in normal times and a priority in times of crisis. There is no 'one-size-fits-all' solution that addresses nutrition. In relevance to the COVID-19 (coronavirus disease 2019) pandemic crisis, viral infections in general and RNA viruses in particular are known to induce and promote oxidative stress, consequently increasing the body's demand for micronutrients, especially those related to antioxidant enzymic systems, thus draining the body of micronutrients, and so hindering the human body's ability to cope optimally with oxidative stress. Common polymorphisms in major antioxidant enzymes, with world population minor allele frequencies ranging from 0·5 to 50 %, are related to altered enzymic function, with substantial potential effects on the body's ability to cope with viral infection-induced oxidative stress. In this review we highlight common SNP of the major antioxidant enzymes relevant to nutritional components in the context of viral infections, namely: superoxide dismutases, glutathione peroxidases and catalase. We delineate functional polymorphisms in several human antioxidant enzymes that require, especially during a viral crisis, adequate and potentially additional nutritional support to cope with the pathological consequences of disease. Thus, in face of the COVID-19 pandemic, nutrition should be tightly monitored and possibly supplemented, with special attention to those carrying common polymorphisms in antioxidant enzymes.

A Polymorphism in the Catalase Gene Promoter Confers Protection against Severe RSV Bronchiolitis

Respiratory syncytial virus (RSV) infection is associated with oxidative lung injury, decreased levels of antioxidant enzymes (AOEs), and the degradation of the transcription factor NF-E2-related factor 2 (NRF2), a master regulator of AOE expression. Single nucleotide polymorphisms (SNPs) in AOE and NRF2 genes have been associated with various lung disorders. To test whether specific NRF2 and/or AOE gene SNPs in children with RSV lower respiratory tract infection were associated with disease severity, one hundred and forty one children <24 month of age with bronchiolitis were assessed for seven AOE and two NRF2 SNPs, and data were correlated with disease severity, which was determined by need of oxygen supplementation and intensive care support. One SNP in the promoter region of the catalase gene, rs1001179, which is associated with higher enzyme expression, was significantly underrepresented (p = 0.01, OR 0.38) among patients with moderate to severe RSV bronchiolitis, suggesting a protective effect against disease severity. Our results suggest that increasing catalase expression/activity could exert a protective role in the context of RSV infection and represent a potential novel therapeutic target to ameliorate viral-induced lung disease.

Associations between the phenotype and genotype of MnSOD and catalase in periodontal disease

BACKGROUND

Periodontal disease is an inflammatory disease in which pathogenic infections trigger a series of inflammatory responses and redox regulation. The hypothesis of this study was that a host's redox regulation, as modified by genetic polymorphisms, may affect periodontal disease activities (including the plaque index (PlI), bleeding on probing (BOP), and pocket depth (PD)) during periodontal therapy.

METHODS

In total, 175 patients diagnosed with periodontitis were recruited from the Department of Periodontology, Taipei Medical University Hospital. Both saliva samples and clinical measurements (PlI, BOP, and PD) were taken at the baseline and at 1 month after completing treatment. Salivary manganese superoxide dismutase (MnSOD) and catalase, and corresponding genetic polymorphisms (MnSOD, T47C, rs4880 and Catalase, C-262 T, rs1001179) were determined. The extent of change (Δ) of MnSOD or catalase was calculated by subtracting the concentration after completing treatment from that at the baseline.

RESULTS

Subjects who carried the Catalase CC genotype had significantly higher salivary MnSOD or catalase levels. The MnSOD genotype had a significant effect on the percentage of PDs of 4~9 mm (p = 0.02), and salivary ΔMnSOD had a significant effect on the PlI (p = 0.03). The Catalase genotype had a significant effect on the PlI (p = 0.01~0.04), but the effect was not found for the mean PlI or PD. There was a significant interaction between the MnSOD genotype and salivary ΔMnSOD on PDs of 4~9 mm. After adjusting for gender, years of schooling, smoking status, and alcohol consumption, subjects with ΔMnSOD of < 0 μg/ml or Δcatalase of < 0 μg/ml had significantly higher 5.58- or 5.17-fold responses to scaling and root planing treatment.

CONCLUSIONS

The MnSOD T47C genotype interferes with the phenotype of salivary antioxidant level, alters MnSOD levels, and influences the PD recovery. MnSOD and catalase gene polymorphism associated with phenotype expression and susceptibility in periodontal root planing treatment responses.

Catalase C-262T Gene Variant in Patients with Bronchial Asthma

Bronchial asthma (BA) is a chronic inflammatory disease of the airways in the pathogenesis of which oxidative stress has a very important role. Single nucleotide polymorphisms (SNPs) in catalase gene may result in decreased antioxidative defense capacity, and thus a higher risk for BA development. Since oxidative stress has an important role in the pathogenesis of BA and catalase has a key role in antioxidant defense, the aim of this study was to examine the association of CAT C-262T polymorphism with BA in Serbian patients with BA.

A total of 170 subjects (79 patients with BA and 91 controls) were screened for CAT C-262T SNP using PCR-RFLP method.

The analysis of genotype distribution did not show statistically significant differences between BA patients and controls (p > 0.05). Moreover, no differences were detected when comparison was performed based on dominant or recessive model. The distribution of CAT-262C and CAT-262T alleles did not show differences between patients and healthy controls (p = 0.715; OR = 1.091; 95% CI = 0.684–1.741). Further analysis of genotype and allele distributions, based on stratification by sex, did not show significant differences between BA patients and controls (p > 0.05).

This is the first study that examined CAT C-262T (rs1001179) SNP in Serbian patients with BA. The results obtained in this study showed that biallelic SNP at the position-262 in the catalase gene is not associated with BA in the Serbian population.

Association of Catalase and Glutathione Peroxidase 1 Polymorphisms with Chronic Hepatitis C Outcome

The hepatic damage caused by hepatitis C virus (HCV) infection is associated with the host immune response and viral regulatory factors. Catalase (CAT) and glutathione peroxidase 1 (GPX1) are antioxidant enzymes located in the peroxisomes and mitochondria, respectively, and are responsible for the control of intracellular hydrogen peroxide levels. Polymorphisms in CAT (C-262T) and GPX1 (Pro198Leu) are correlated with serum levels and enzyme activity. This study aimed to investigate the association of genetic polymorphisms of CAT C-262T (rs1001179) and GPX1 Pro198Leu (rs1050450) with different stages of liver fibrosis and development of hepatocellular carcinoma (HCC). This study included 445 patients with chronic hepatitis C, of whom 139 patients had mild fibrosis (F0-F1), 200 had moderate/severe fibrosis (F2-F4), and 106 had HCC. Genotyping of SNPs was performed by real-time PCR using TaqMan probes. The Pro/Pro genotype of GPX1 was significantly associated with fibrosis severity, HCC, Child Pugh score, and BCLC staging. Additionally, patients carrying both CT+TT genotypes in the CAT gene and the Pro/Pro genotype in the GPX1 gene had higher risk for developing moderate/severe fibrosis or HCC (p = 0.009, OR 2.40 and p = 0.002, OR 3.56, respectively). CAT and GPX1 polymorphisms may be implicated in the severity of liver fibrosis and HCC caused by HCV.

Association of Nrf2 with airway pathogenesis: lessons learned from genetic mouse models

Nrf2 is a key transcription factor for antioxidant response element (ARE)-bearing genes involved in diverse host defense functions including redox balance, cell cycle, immunity, mitochondrial biogenesis, energy metabolism, and carcinogenesis. Nrf2 in the airways is particularly essential as the respiratory system continuously interfaces with environmental stress. Since Nrf2 was determined to be a susceptibility gene for a model of acute lung injury, its protective capacity in the airways has been demonstrated in experimental models of human disorders using Nrf2 mutant mice which were susceptible to supplemental respiratory therapy (e.g., hyperoxia, mechanical ventilation), cigarette smoke, allergens, virus, environmental pollutants, and fibrotic agents compared to wild-type littermates. Recent studies also determined that Nrf2 is indispensable in developmental lung injury. While association studies with genetic NRF2 polymorphisms supported a protective role for murine Nrf2 in oxidative airway diseases, somatic NRF2 mutations enhanced NRF2-ARE responses, and were favorable for lung carcinogenesis and chemoresistance. Bioinformatic tools have elucidated direct Nrf2 targets as well as Nrf2-interacting networks. Moreover, potent Nrf2-ARE agonists protected oxidant-induced lung phenotypes in model systems, suggesting a therapeutic or preventive intervention. Further investigations on Nrf2 should yield greater understanding of its contribution to normal and pathophysiological function in the airways.

[Genetic and biochemical mechanisms of involvement of antioxidant defense enzymes in the development of bronchial asthma]

In the present review we have analyzed and summarized recent literature data on genetic and biochemical mechanisms responsible for involvement of antioxidant defense enzymes in the etiology and pathogenesis of bronchial asthma. It has been shown that the mechanisms of asthma development are linked with genetically determined abnormalities in the functioning of antioxidant defense enzymes. These alterations are accompanied by a systemic imbalance between oxidative and anti-oxidative reactions with the shift of the redox state toward increased free radical production and oxidative stress, a key element in the pathogenesis of bronchial asthma.

Chronic effects of air pollution on respiratory health in Southern California children: findings from the Southern California Children's Health Study

Outdoor air pollution is one of the leading contributors to adverse respiratory health outcomes in urban areas around the world. Children are highly sensitive to the adverse effects of air pollution due to their rapidly growing lungs, incomplete immune and metabolic functions, patterns of ventilation and high levels of outdoor activity. The Children's Health Study (CHS) is a continuing series of longitudinal studies that first began in 1993 and has focused on demonstrating the chronic impacts of air pollution on respiratory illnesses from early childhood through adolescence. A large body of evidence from the CHS has documented that exposures to both regional ambient air and traffic-related pollutants are associated with increased asthma prevalence, new-onset asthma, risk of bronchitis and wheezing, deficits of lung function growth, and airway inflammation. These associations may be modulated by key genes involved in oxidative-nitrosative stress pathways via gene-environment interactions. Despite successful efforts to reduce pollution over the past 40 years, air pollution at the current levels still brings many challenges to public health. To further ameliorate adverse health effects attributable to air pollution, many more toxic pollutants may require regulation and control of motor vehicle emissions and other combustion sources may need to be strengthened. Individual interventions based on personal susceptibility may be needed to protect children's health while control measures are being implemented.

The role of genetic polymorphisms in antioxidant enzymes and potential antioxidant therapies in neonatal lung disease

SIGNIFICANCE

Oxidative stress is involved in the development of newborn lung diseases, such as bronchopulmonary dysplasia and persistent pulmonary hypertension of the newborn. The activity of antioxidant enzymes (AOEs), which is impaired as a result of prematurity and oxidative injury, may be further affected by specific genetic polymorphisms or an unfavorable combination of more of them.

RECENT ADVANCES

Genetic polymorphisms of superoxide dismutase and catalase were recently demonstrated to be protective or risk factors for the main complications of prematurity. A lot of research focused on the potential of different antioxidant strategies in the prevention and treatment of lung diseases of the newborn, providing promising results in experimental models.

CRITICAL ISSUES

The effect of different genetic polymorphisms on protein synthesis and activity has been poorly detailed in the newborn, hindering to derive conclusive results from the observed associations with adverse outcomes. Therapeutic strategies that aimed at enhancing the activity of AOEs were poorly studied in clinical settings and partially failed to produce clinical benefits.

FUTURE DIRECTIONS

The clarification of the effects of genetic polymorphisms on the proteomics of the newborn is mandatory, as well as the assessment of a larger number of polymorphisms with a possible correlation with adverse outcome. Moreover, antioxidant treatments should be carefully translated to clinical settings, after further details on optimal doses, administration techniques, and adverse effects are provided. Finally, the study of genetic polymorphisms could help select a specific high-risk population, who may particularly benefit from targeted antioxidant strategies.

Oxidative stress-related enzyme polymorphisms associated with the immunological biomarkers levels in heavy drinkers in Taiwan

BACKGROUND

Excessive alcohol intake can result in the oxidative stress in cells and the genetic variations of alcohol-metabolizing enzymes are responsible for the different degrees of toxicity of alcohol in several organs, such as the liver and immunological systems. We hypothesized that the alteration of oxidative stress due to some genetic variations of oxidative stress-related enzymes could result in changes of specific biomarkers, and heavy drinkers could be cautioned about the predictive likelihood to induce drinking-induced diseases.

METHODS

A total of 108 heavy drinkers and 106 nonheavy drinkers were enrolled and the hematological, biochemical, and immunological tests were measured; the genotypes of oxidative stress-related enzymes, including manganese superoxide dismutase (MnSOD1183T>C), glutathione peroxidase 1 (GPX1Pro198Leu), catalase (CAT-262C>T), and myeloperoxidase (MPO-463G>A), were assayed by real-time polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

For the males, the levels of carbohydrate-deficient transferrin (CDT), malondialdehyde (MDA), CD4(+), immunoglobulin G (IgG), immunoglobulin M (IgM), and IL-6 were significantly different between the two groups. Furthermore, there were higher proportions of CD19(+) cells and lower TNF-α levels in heavy drinkers with the MnSOD C carriers, and there were higher percentages of CD19(+) cells and IL-6 levels in heavy drinkers with the combined genotypes of MnSOD C carriers and MPO A carriers.

CONCLUSIONS

Our findings indicate that heavy drinkers may be cautioned predictive likelihood for them to induce drinking-induced diseases by analyzing their MnSOD genotypes and immunological biomarkers.

Combustion-derived flame generated ultrafine soot generates reactive oxygen species and activates Nrf2 antioxidants differently in neonatal and adult rat lungs

BACKGROUND

Urban particulate matter (PM) has been epidemiologically correlated with multiple cardiopulmonary morbidities and mortalities, in sensitive populations. Children exposed to PM are more likely to develop respiratory infections and asthma. Although PM originates from natural and anthropogenic sources, vehicle exhaust rich in polycyclic aromatic hydrocarbons (PAH) can be a dominant contributor to the PM2.5 and PM0.1 fractions and has been implicated in the generation of reactive oxygen species (ROS).

OBJECTIVES

Current studies of ambient PM are confounded by the variable nature of PM, so we utilized a previously characterized ethylene-combusted premixed flame particles (PFP) with consistent and reproducible physiochemical properties and 1) measured the oxidative potential of PFP compared to ambient PM, 2) determined the ability of PFPs to generate oxidative stress and activate the transcription factor using in vitro and ex vivo models, and 3) we correlated these responses with antioxidant enzyme expression in vivo.

METHODS

We compared oxidative stress response (HMOX1) and antioxidant enzyme (SOD1, SOD2, CAT, and PRDX6) expression in vivo by performing a time-course study in 7-day old neonatal and young adult rats exposed to a single 6-hour exposure to 22.4 μg/m3 PFPs.

RESULTS

We showed that PFP is a potent ROS generator that induces oxidative stress and activates Nrf2. Induction of the oxidative stress responsive enzyme HMOX1 in vitro was mediated through Nrf2 activation and was variably upregulated in both ages. Furthermore, antioxidant enzyme expression had age and lung compartment variations post exposure. Of particular interest was SOD1, which had mRNA and protein upregulation in adult parenchyma, but lacked a similar response in neonates.

CONCLUSIONS

We conclude that PFPs are effective ROS generators, comparable to urban ambient PM2.5, that induce oxidative stress in neonatal and adult rat lungs. PFPs upregulate a select set of antioxidant enzymes in young adult animals, that are unaffected in neonates. We conclude that the inability of neonatal animals to upregulate the antioxidant response may, in part, explain enhanced their susceptibility to ultrafine particles, such as PFP.

Manganese superoxide dismutase Ile58Thr, catalase C-262T and myeloperoxidase G-463A gene polymorphisms in patients with prostate cancer: relation to advanced and metastatic disease

OBJECTIVE

To evaluate the relationship between manganese superoxide dismutase (MnSOD) Ile58Thr, catalase (CAT) C-262T and myeloperoxidase (MPO) G-463A gene polymorphisms and the susceptibility and clinicopathological characteristics of prostate cancer.

PATIENTS AND METHODS

In all, 155 patients diagnosed with prostate cancer and 195 controls with negative digital rectal examinations and PSA levels of <4 ng/dL were enrolled in this study. MnSOD, CAT and MPO gene polymorphisms were identified by polymerase chain reaction restriction-fragment length polymorphism methods.

RESULTS

The TT genotype in MnSOD Ile58Thr polymorphism, CC genotype in the CAT C-262T polymorphism and the GG genotype in the MPO G-463A polymorphism were the predominant genotypes amongst this Turkish male population. There was no association between MnSOD Ile58Thr polymorphism and prostate cancer. For the CAT C-262T polymorphism, the TT genotype had significantly increased prostate cancer risk compared with the CC genotype. Similarly, the TT genotype had a 1.94- and 3.83-fold increased risk for high-stage disease and metastasis, respectively, when compared with the CC genotype. For the MPO G-463A polymorphism, the GG genotype had 1.78-fold increased risk of prostate cancer compared with the AA genotype. However, no association was found regarding Gleason score, advanced and metastatic prostate cancer risk.

CONCLUSIONS

It seems that there is no association of prostate cancer with MnSOD Ile58Thr polymorphism, whereas the TT genotype in the CAT C-262T polymorphism and the GG genotype in the MPO G-463A polymorphism may be associated with increased prostate cancer risk. The TT genotype in the CAT C-262T gene polymorphism may also be a risk factor in tumour progression and metastasis among Turkish men.

Association of the -262C/T polymorphism in the catalase gene promoter and the C242T polymorphism of the NADPH oxidase P22phox gene with essential arterial hypertension in patients with diabetes mellitus type 2

AIM

The aim of the present study was to test the association between genetic polymorphisms with functional effects on redox regulation: the -262C/T of the catalase gene promoter (rs1001179), the C242T of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase P22phox gene (rs4673), and the 594C/T polymorphism of the glutathione peroxidase gene (rs1050450) and arterial hypertension (AH) in patients with type 2 diabetes.

METHODS

810 Slovenian subjects (Caucasians) with type 2 diabetes were enrolled in the cross-sectional study. Genotypes were determined by real-time PCR.

RESULTS

Univariate analysis failed to demonstrate an association between either the -262C/T of the catalase gene promoter (rs1001179) or the C242T polymorphism of the P22phox gene (rs4673) or the 594C/T polymorphism of the glutathione peroxidase gene (rs1050450) and AH. After adjustment for age, body mass index, fibrinogen level and high sensitivity C-reactive protein level, rs4673 was found to be an independent risk factor for AH in subjects with type 2 diabetes, whereas rs1001179 and rs1050450 were not.

CONCLUSION

According to the results of cross-sectional study, the tested polymorphism of the NADPH oxidase P22phox gene (rs4673) was found to be associated with the development of AH, indicating that the oxidative stress gene NADPH oxidase might be implicated in the pathogenesis of AH in subjects with type 2 diabetes.

Catalase gene C-262T polymorphism: importance in ulcerative colitis

BACKGROUND AND AIM

Reactive oxygen species (ROS) are by-products of the cellular metabolism and have important roles in the normal physiology of the cell. However, when ROS production exceeds the antioxidant capacity, a state known as oxidative stress, damage to cellular macromolecules emerges. A crucial role in counteracting ROS is played by the enzyme catalase. A common polymorphism in the catalase (CAT) promoter region (C-262T) alters the expression as well as blood catalase levels, and leads to a number of human diseases. Ulcerative colitis (UC) is an inflammatory condition of the large bowel that is known to be influenced by oxidative stress. In this study, we aimed to evaluate the association of CAT C-262T polymorphism on the risk of UC.

METHODS

Samples were collected from 60 patients diagnosed with UC and 78 control subjects, and genotyped by allele-specific polymerase chain reaction.

RESULTS

We found that CAT C-262T genotype frequencies were significantly different between cases and controls (P = 0.002). Individuals carrying the -262C/T genotype had a greater risk for UC compared with C/C genotype (odds ratio, 4.88; 95% confidence interval, 1.73-13.75, P = 0.002).

CONCLUSIONS

This study indicates that CAT C-262T polymorphism may be associated with UC, and that the -262C/T genotype may be a risk factor for the disease. Further studies are needed to confirm the results.

Association study of genes associated to asthma in a specific environment, in an asthma familial collection located in a rural area influenced by different industries

Eight candidate genes selected in this study were previously associated with gene-environment interactions in asthma in an urban area. These genes were analyzed in a familial collection from a founder and remote population (Saguenay-Lac-Saint-Jean; SLSJ) located in an area with low air levels of ozone but with localized areas of relatively high air pollutant levels, such as sulphur dioxide, when compared to many urban areas. Polymorphisms (SNPs) were extracted from the genome-wide association study (GWAS) performed on the SLSJ familial collection. A transmission disequilibrium test (TDT) was performed using the entire family sample (1,428 individuals in 254 nuclear families). Stratification according to the proximity of aluminium, pulp and paper industries was also analyzed. Two genes were associated with asthma in the entire sample before correction (CAT and NQO1) and one was associated after correction for multiple analyses (CAT). Two genes were associated when subjects were stratified according to the proximity of aluminium industries (CAT and NQO1) and one according to the proximity of pulp and paper industries (GSTP1). However, none of them resisted correction for multiple analyses. Given that the spatial pattern of environmental exposures can be complex and inadequately represented by a few stationary monitors and that exposures can also come from sources other than the standard outdoor air pollution (e.g., indoor air, occupation, residential wood smoke), a new approach and new tools are required to measure specific and individual pollutant exposures in order to estimate the real impact of gene-environment interactions on respiratory health.

Catalase polymorphisms and metabolic diseases

PURPOSE OF REVIEW

This review summarizes our current understanding of the implication of catalase polymorphisms in the occurrence, control and comorbidities of metabolic diseases.

RECENT FINDINGS

Whatever impaired glucose tolerance, insulin resistance on diabetes and whatever their occurrence or implications, the studies taken together converge toward the hypothesis that catalase polymorphisms play a role in glucose disorders. -262C/T and -844A>G single nucleotide polymorphisms are associated to hypertension susceptibility and/or onset. Concerning dyslipidemia, very recent studies requiring confirmation report a -262C/T implication. Finally, a role of catalase polymorphisms in bone metabolism is described.

SUMMARY

Plethora of studies on catalase SNPs and their link with diseases exist. It is now clear that genetic variations in the catalase gene and its promoter are putative risk factors for metabolic disease. The question of how these polymorphisms actively play a role in various metabolisms remains unanswered. Further functional studies are required in order to gain a deeper insight into the direct role of catalase.

Genetic polymorphisms of antioxidant enzymes as risk factors for oxidative stress-associated complications in preterm infants

We aimed to identify specific polymorphisms of genes encoding for superoxide dismutase (SOD) 1 (cytoplasmic Cu/ZnSOD), SOD2 (mitochondrial MnSOD), SOD3 (extracellular Cu/ZnSOD) and CAT in a cohort of preterm infants and correlate their presence to the development of respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) and retinopathy of prematurity (ROP). We carried out a retrospective study to evaluate the allele frequency and the genotype distribution of polymorphisms of SODs and CAT in a population of preterm neonates (n = 152) with a gestational age ≤ 28 weeks according to the presence or absence of RDS, BPD, IVH and ROP. Moreover, we evaluated through the haplotype reconstruction analysis whether combinations of the selected polymorphisms are related to the occurrence of RDS, BPD, IVH and ROP. We found that rs8192287 SOD3 polymorphism is an independent protective factor for all grade IVH, while rs4880 and rs5746136 SOD2 polymorphisms are associated with a lower gestational age (rs4880, rs5746136) and birth weight (rs4880). Haplotypes reconstruction showed that SOD1 (GG) decreased the risk of RDS, IVH and ROP; SOD2 (GT) increased the risk of BPD and decreased the risk of RDS, IVH and ROP; SOD3 (TGC) decreased the risk of BPD and IVH; and 4) CAT (CTC) decreased the risk of RDS. The rs8192287 SOD3 polymorphism is per se an independent predictor of a decreased risk of developing IVH. Different SOD2 polymorphisms are associated per se with a lower gestational age and/or birth weight, and haplotypes of SOD1, SOD3 and CAT genes may be independent protecting or risk markers for prematurity complications.

Relationships between single nucleotide polymorphisms of antioxidant enzymes and disease

The presence and progression of numerous diseases have been linked to deficiencies in antioxidant systems. The relationships between single nucleotide polymorphisms (SNPs) arising from specific antioxidant enzymes and diseases associated with elevated oxidative stress have been studied with the rationale that they may be useful in screening for diseases. The purpose of this narrative review is to analyse evidence from these studies. The antioxidant enzyme SNPs selected for analysis are based on those most frequently investigated in relation to diseases in humans: superoxide dismutase (SOD2) Ala16Val (80 studies), glutathione peroxidise (GPx1) Pro197Leu (24 studies) and catalase C-262T (22 studies). Although the majority of evidence supports associations between the SOD2 Ala16Val SNP and diseases such as breast, prostate and lung cancers, diabetes and cardiovascular disease, the presence of the SOD2 Ala16Val SNP confers only a small, clinically insignificant reduction (if any) in the risk of these diseases. Other diseases such as bladder cancer, liver disease, nervous system pathologies and asthma have not been consistently related to this SOD SNP genotype. The GPx1 Pro197Leu and catalase C-262T SNP genotypes have been associated with breast cancer, but only in a small number of studies. Thus, currently available evidence suggests antioxidant enzyme SNP genotypes are not useful for screening for diseases in humans.

Genetic polymorphisms in antioxidative enzymes are associated to forced expiratory volume in 1 s (FEV1) in smokers independently of asthma

INTRODUCTION

In this study, we hypothesised that the genotypes coding for low antioxidative enzyme activity are associated with asthma and reduced lung function.

METHODS

Using the European Community Respiratory Health Survey protocol, we enlisted 1091 Danish subjects in this cross-sectional study. Asthma phenotypes were defined as asthma symptoms in combination with steroid usage, bronchial hyperresponsiveness and atopy. These phenotypes and lung function were analysed with respect to glutathione peroxidase, GPX1 (Pro198Leu, rs1050450), manganese superoxide dismutase, SOD2 (Ala16Val, rs4880) and three glutathione S-transferases; GSTP1 (Ile105Val, rs1695), GSTT1 (gene copy number) and GSTM1 (gene copy number).

RESULTS

We found no associations between these genotypes and the asthma phenotypes. For the 201 subjects identified as current smokers and recruited via random sampling, an association was seen between increasing number of genotypes coding for high antioxidative enzyme activity (GPX1 Pro/Pro, SOD2 Val/Val, GSTP1 Ile/Ile, GSTT1 two copies, GSTM1 two copies) and forced expiratory volume in 1 s (FEV1%) predicted. The increase in FEV1% predicted was 2.0% (95% confidence interval 0.3-3.8) per genotype. There was no identified significance for the inverse association between FEV1% predicted and number of genotypes coding for low antioxidative enzyme activity.

CONCLUSION

The present study does not support the hypothesis that asthma is associated with genotypes of these major antioxidative enzymes. However, we speculate that since we see an impact of these genotypes on lung function in young adult smokers, polymorphisms in antioxidative enzymes may contribute to the range of susceptibility of smokers have to Chronic obstructive lung disease.

The association between adult asthma and superoxide dismutase and catalase gene activity

BACKGROUND

Adult asthma is caused by interaction effects of multiple genetic and environmental factors. Some studies have suggested that antioxidant enzyme activity and gene polymorphisms may play important roles in the context of asthma. Therefore, our study objectives were to investigate the association between asthma, antioxidant activities and the polymorphisms of manganese superoxide dismutase (Mn-SOD) or catalase (CAT).

MATERIALS AND METHODS

A case-control study, for which we recruited 250 asthmatic adults and 250 age- and sex-matched controls. All subjects completed a questionnaire. Waist and hip circumference measurements, a lung function test and DNA genotyping were performed. In total, 50 incident cases and 50 matched controls who were non-smokers or had quit smoking for at least 1 year were selected in order to investigate SOD and CAT activity levels.

RESULTS

In our study, we did not find a significant association between Mn-SOD Ala16Val, CAT C-262T and asthma. The level of SOD activity in new-onset asthma patients was significantly lower than in control subjects (p < 0.0005). The level of CAT activity in new-onset asthma patients was significantly higher than in control subjects (p < 0.0005).

CONCLUSIONS

The levels of SOD and CAT activity were significantly related to adult asthma. SOD and CAT activity may be good tools to differentiate potential asthma sufferers. This would enable us to further investigate the mechanism of defective antioxidant enzymes in the context of asthma pathogenesis.

Association of the −262C/T polymorphism in the catalase gene promoter with carotid atherosclerosis in Slovenian patients with type 2 diabetes

Genetic variations of the antioxidant enzymes may influence the susceptibility to oxidative stress and consequently the development and progression of diabetic complications. The aim of the current study was to test the association between the −262C/T polymorphism in the catalase gene promoter and carotid atherosclerosis in Slovenian patients with type 2 diabetes. Two-hundred and eighty six diabetics and 150 healthy controls were enrolled in the study. Carotid atherosclerosis was quantified ultrasonographiocally by carotid intima-media thickness (CITM), plaque score and plaque type. Genotypes were determined using the real-time PCR. Fibrinogen concentration showed a borderline statistically significant difference due to catalase genotypes (p=0,05). No difference in clinical characteristics, CIMT, plaque stability or plaque score was observed. Logistic regression model adjusted for age, gender, smoking, BMI, lipid parameters and duration of hypertension and diabetes showed significant association of T allele and lower risk for higher plaque score (OR=0,25; p=0,025). No association with CIMT>1mm and unstable plaques was observed. T allele of −262C/T is associated with lower risk for higher plaque score but it did not affect clinical parameters, CIMT and plaque stability. Whether this polymorphism can be used as a genetic marker for advanced carotid atherosclerosis in diabetic patients needs to be evaluated in the future.

Genetic polymorphisms influence runners' responses to the dietary ingestion of antioxidant supplementation based on pequi oil (Caryocar brasiliense Camb.): a before-after study

Genes have been implicated in the levels of oxidative stress, lipids, CVD risk, immune reactivity, and performance. Pequi oil (Caryocar brasiliense) has shown anti-inflammatory and hypotensive effects, besides reducing exercise-induced DNA, tissue damages, and anisocytosis. Given that diet can interact with the human genome to influence health and disease, and because genetic variability can influence response to diet, we aim to investigate the influence of 12 gene polymorphisms on inflammatory markers, postprandial lipids, arterial pressure, and plasma lipid peroxidation of runners (N = 125), before and after 14 days of 400 mg pequi-oil supplementation, after races under closely comparable conditions. Arterial pressure was checked before races; blood samples were taken immediately after racing to perform leukogram and plateletgram, Tbars assay, lipid, and CRP dosages and genotyping. CAT, GST-M1/T1, CRP-G1059C, and MTHFR-C677T polymorphisms influenced post-pequi-oil responses in leukogram; Hp and MTHFR-C677T, in plateletgram; Hp, ACE, GSTT1, and MTHFR-A1298C, in lipid profile; MTHFR-A1298C, in C-reactive protein (CRP) levels; and Hp and MnSOD, in Tbars assay. Differences between ACE genotypes in leukogram and total cholesterol disappeared after pequi, and the same occurred for Hp and MnSOD in Tbars assay and for MTHFR-A1298C with CRP levels. Because genetic inheritance is one of the factors that drive atherosclerosis-related lipid abnormalities, results can contribute to a greater understanding of the influence of genetic polymorphisms in situations that push up free radicals. Knowledge is also expanded on how antioxidant supplementation affects an individual's genes and how athletic genetic makeup can affect the way a person responds to antioxidant supplements.

Genetic factors in contact allergy--review and future goals

The genetics of contact allergy are still only partly understood, despite decades of research; this might be a consequence of inadequately defined phenotypes used in the past. A recommendation is to study an extreme phenotype, namely, polysensitization (sensitization to three or more unrelated allergens). Another approach to unravel the genetics of contact allergy is the study of candidate genes. In this review, we summarize studies on the associations between genetic variation (e.g. single-nucleotide polymorphisms) in certain candidate genes and contact allergy. Polymorphisms and mutations affecting the following proteins were studied: (i) filaggrin; (ii) N-acetyltransferase (NAT) 1 and 2; (iii) glutathione-S-transferase (GST) M and T; (iv) manganese superoxide dismutase; (v) angiotensin-converting enzyme (ACE); (vi) tumour necrosis factor (TNF); and (vii) interleukin-16 (IL-16). The polymorphisms of NAT1, NAT2, GSTM, GSTT, ACE, TNF and IL-16 were shown to be associated with an increased risk of contact allergy. In one of our studies, the increased risk conferred by the TNF and IL-16 polymorphisms was confined to polysensitized individuals. Other relevant candidate genes may be identified by studying diseases related to contact allergy in terms of clinical symptoms, a more general pathology (inflammation), and possibly an overlapping genetic background, such as irritant contact dermatitis.

Differences in associations between markers of antioxidative defense and asthma are sex specific

BACKGROUND

Lungs are exposed to high levels of oxygen, air pollutants, and smoke, all of which stimulate the production of reactive oxygen species (ROS). In addition, inflammatory cells produce ROS, and thus there may be increased demand for antioxidants, including antioxidant enzymes, in inflammatory lung diseases such as asthma. Sex-specific differences have been noted for asthma, which in postpubertal subjects is predominantly found in females. These sex-specific differences may be associated with differences on the molecular level as well.

OBJECTIVE

The aim of this cross-sectional study was to examine associations between markers of antioxidative defense and asthma, and to investigate whether these associations were different between women and men.

METHODS

Based on the European Community Respiratory Health Survey protocol, subjects were enrolled in a study of asthma risk factors. The multicenter study was conducted in 5 west Danish counties between 2003 and 2006, and the subjects were recruited as a case-enriched random sample of 10,000 Danish inhabitants aged 20 to 44 years selected by their civil registration number. Participants were identified by positive answers to asthma questions on a screening questionnaire, random sampling, or both. Serum selenium concentrations and antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase [GPX], glutathione reductase [GR], and glucose-6-phosphate dehydrogenase [G6PD]) in erythrocytes were measured. Asthma was defined as either current asthma symptoms with bronchial hyperresponsiveness (BHR) or a continuous asthma score based on 8 questions.

RESULTS

A total of 1191 mostly white women and men (mean [SD] age, 34.0 [7.1] and 35.1 [7.1] years, respectively) were enrolled in the study. Current asthma symptoms were present in 29.9% (200/670) of women and 22.5% (117/521) of men, with women reporting more positive answers (51.1% vs 40.9%, respectively; P < 0.01) to asthma questions. Serum selenium concentrations were measured in 1151 subjects (640 women, 511 men), and antioxidant enzyme activities were measured in 295 subjects (161 women, 134 men). Women had higher enzyme activities of most antioxidant enzymes (GPX, P = 0.006; GR, P < 0.001; and G6PD, P = 0.009) than did men. Although the serum selenium concentration was inversely associated with asthma in both sexes, there was a female preponderance, with 3.5% lower serum selenium in subjects with current asthma symptoms with BHR (n = 77) compared with controls (n = 287). GR activity was associated with asthma in men, with 5.7% higher enzyme activity in subjects with current asthma symptoms with BHR (n = 14) compared with controls (n = 77). However, a significant interaction with gender was observed for analyses of GR (P = 0.02), but not for analyses of selenium.

CONCLUSIONS

In this study of asthma risk factors, women had higher levels of enzyme activities than did men in a randomly selected Danish population, and sex-specific differences were found in the associations between markers of antioxidative defense and asthma.

Genetic polymorphism of manganese superoxide dismutase is associated with childhood asthma

OBJECTIVE

Cellular defenses against allergens and reactive oxygen species (ROS) exposure are critical in the pathogenesis of asthma. CD14 is a receptor for various bacterial products, such as lipopolysaccharides (LPS), and is also a mediator of inflammatory processes. Manganese superoxide dismutase (MnSOD) is an ROS scavenger, and myeloperoxidase (MPO) can convert hydrogen peroxide into hypochlorous acid; thus, they are considered to be involved in inflammatory defense. The authors conducted a case-control study to evaluate the susceptibility to childhood asthma based on CD14, MnSOD, and MPO genes.

METHODS

The CD14 -260, MnSOD -9, and MPO -463 genotypes were identified by polymerase chain reactions for 116 asthmatic children and 232 healthy controls. Questionnaires were administered to obtain demographic characteristics. Allergen testing used common Taiwanese aeroallergens.

RESULTS

A higher level of parental education, family history of asthma, incense burning at home, allergen-test positive, and the MnSOD Val-Ala/Ala-Ala genotypes (matched relative risk = 2.0; 95% confidence interval = 1.0-4.2) were significantly associated with childhood asthma. Interactions between CD14, MnSOD, MPO genotypes and allergy status were significantly associated with asthma risk in these children (all p <.001). Furthermore, atopic cases with MnSOD Val-Ala/Ala-Ala (log eosinophil 2.66/mm(3), log total serum immunoglobulin E [IgE] 2.48 IU/ml) or Val-Val (log eosinophil 2.61/mm(3), log total serum IgE 2.63 IU/ml) genotypes had elevated eosinophil counts and total serum IgE levels as compared to nonatopic cases with MnSOD Val-Val genotype (log eosinophil 2.27/mm(3), log total serum IgE 1.83 IU/ml).

CONCLUSIONS

Susceptible MnSOD genotypes might modulate the development of asthma in Taiwanese children.

Air pollution and homocysteine: more evidence that oxidative stress-related genes modify effects of particulate air pollution

BACKGROUND

Ambient particles are associated with cardiovascular events and recently with total plasma homocysteine. High total plasma homocysteine is a risk for human health. However, the biologic mechanisms are not fully understood. One of the putative pathways is through oxidative stress. We aimed to examine whether associations of PM2.5 and black carbon with homocysteine were modified by genotypes including HFE H63D, C282Y, CAT (rs480575, rs1001179, rs2284367, and rs2300181), NQO1 (rs1800566), GSTP1 I105V, GSTM1, GSTT1 (deletion vs. nondeletion), and HMOX-1 (any short vs. both long). We attempted to replicate identified genes in an analysis of heart rate variability and in other outcomes reported in the literature.

METHODS

Study subjects were 1000 white non-Hispanic men in the Boston area, participating in a cohort study of aging. PM2.5, black carbon, total plasma homocysteine, and other covariates were measured at several points in time between 1995 and 2006. We fit mixed models to examine effect modification of genes on associations of pollution with total plasma homocysteine.

RESULTS

Interquartile range increases in PM2.5 and black carbon (7-day moving averages) were associated with 1.5% (95% confidence interval = 0.2% to 2.8%) and 2.2% (0.6% to 3.9%) increases in total plasma homocysteine, respectively. GSTT1 and HFE C282Y modified effects of black carbon on total plasma homocysteine, and HFE C282Y and CAT (rs2300181) modified effects of PM2.5 on homocysteine. Several genotypes marginally modified effects of PM2.5 and black carbon on various endpoints. All genes with significant interactions with particulate air pollution had modest main effects on total plasma homocysteine.

CONCLUSIONS

: Effects of PM2.5 and black carbon on various endpoints appeared to be mediated by genes related to oxidative stress pathways.

CAT C-262T and GPX1 Pro198Leu polymorphisms in a Turkish population

Oxidative stress is believed to play an important role in the pathogenesis of considerable number of complex diseases. The antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPX) are important components of cell defense against oxidative stress, and polymorphisms in the genes which regulate their expression may contribute to differences in susceptibility of individuals to oxidative damage caused by reactive oxygen species. The aim of this study was to assess the distribution of CAT C-262T and GPX1 Pro198Leu genotypic variants in a Turkish population. Genotyping analyses of CAT and GPX1 were conducted in 250 unrelated, healthy volunteers by the PCR-RFLP assay. The allele frequencies were 0.784 (C) and 0.216 (T) for CAT and 0.636 (C) and 0.364 (T) for GPX1 Pro198Leu. The genotype frequencies were 0.632 (CC), 0.304 (CT), and 0.064 (TT) for CAT and 0.416 (CC), 0.44 (CT), and 0.144 (TT) for GPX1 Pro198Leu. The genotype frequencies did not deviate from Hardy-Weinberg equilibrium. The results are compared with those of other reported populations. They showed marked ethnic group differences.

Functional variants in the catalase and myeloperoxidase genes, ambient air pollution, and respiratory-related school absences: an example of epistasis in gene-environment interactions

The individual effect of functional single nucleotide polymorphisms within the catalase and myeloperoxidase genes (CAT and MPO) has been studied in relation to asthma; however, their interrelationship with ambient air pollution exposures has yet to be determined. The authors investigated the interrelationships between variants in CAT and MPO, ambient air pollutants, and acute respiratory illness. Health information, air pollution, and incident respiratory-related school absences were ascertained in January-June 1996 for 1,136 Hispanic and non-Hispanic white US elementary schoolchildren as part of the prospective Children's Health Study. Functional and tagging single nucleotide polymorphisms for the CAT and MPO loci were genotyped. The authors found epistasis between functional polymorphisms in the CAT/MPO loci, which differed by levels of oxidant-stress-producing air pollutants. Risk of respiratory-related school absences was elevated for children with the CAT (G/G) and MPO (G/A or A/A) genes (relative risk = 1.35, 95% confidence interval: 1.03, 1.77; P-interaction = 0.005). The epistatic effect of CAT and MPO variants was most evident in communities exhibiting high ambient ozone levels (P-interaction = 0.03). The association of respiratory-illness absences with functional variants in CAT and MPO that differ by air pollution levels illustrates the need to consider genetic epistasis in assessing gene-environment interactions.

Tobacco smoking, fruit and vegetable intake modify association between -21A>T polymorphism of catalase gene and risk of bronchial asthma

Although oxidative stress is a cardinal feature of bronchial asthma, the role of interactions between environmental oxidant/antioxidant exposures and antioxidant genes in asthma aetiology has yet to be determined. The present study was conducted to investigate whether two common polymorphisms -21A > T and -262C > T of catalase (CAT) gene are associated with susceptibility to asthma in a Russian population and to test the hypothesis that the asthma risk attributed to CAT genotypes could be dependent on both oxidant (tobacco smoking) and antioxidant (fruit and vegetable intake) exposures. A total of 429 unrelated Russian individuals from Central Russia were recruited in the study, including 215 asthmatics and 214 sex- and age-matched healthy controls. Genotyping analysis for the CAT gene polymorphisms was performed by PCR-RFLP assays. The frequencies of both allele -21A (OR 0.73 95%CI 0.55-0.96 p = 0.03) and -21AA CAT genotype (OR 0.42 95%CI 0.23-0.76 p = 0.004) were higher among asthmatics than among healthy controls. The frequency of -21AA genotype of the CAT gene was significantly higher in patients with allergic (OR 0.47 95%CI 0.25-0.92 p = 0.024) and nonallergic (OR 0.32 95%CI 0.14-0.71 p = 0.004) asthma in comparison with controls (at the Bonferroni corrected p value less than 0.025). Polymorphisms -21A > T and -262C > T of the catalase gene were in a positive linkage disequilibrium (p < 0.0001). Smokers who carried -21AA genotype had an increased risk of nonallergic asthma (p = 0.002), whereas nonsmoker carriers of this genotype did not have the risk of any variant of the disease. Notably, no association of CAT genotype -21AA with asthma was found in high fruit and vegetable consumers, whereas low fruit and vegetable consumers (one time per day or less often) possessing this genotype were at increased risk of both allergic (p = 0.013) and nonallergic (p = 0.008) asthma. This is the first study reporting an association of polymorphism -21A > T of the catalase gene with allergic and nonallergic asthma. We also found, for the first time, that cigarette smoking and fruit and vegetable intakes have potentially inverse modifying influences on the asthma risk in individuals with -21AA CAT genotype and that the gene-environment interactions that were found support the biologic plausibility of catalase gene for the development of bronchial asthma.

Target sequence polymorphism of human manganese superoxide dismutase gene and its association with cancer risk: a review

In normal state of a cell, endogenous antioxidant enzyme system maintains the level of reactive oxygen species generated by mitochondrial respiratory chain. Mitochondrial superoxide dismutase [SOD; manganese SOD (MnSOD) or SOD2] neutralizes highly reactive superoxide radical (O(*-)(2)), the first member in the plethora of mitochondrial reactive oxygen species. A polymorphism in the target sequence of MnSOD enzyme, Val(16)Ala, is known to disrupt proper targeting of the enzyme from cytosol to mitochondrial matrix where it acts on O(*-)(2) to dismutate it to hydrogen peroxide (H(2)O(2)). A change in the level of O(*-)(2) and of H(2)O(2) in mitochondria modulates the molecular mechanisms of apoptosis, cellular adhesion, and cell proliferation and thus play key role in cancer development. Previous studies investigating the association between MnSOD Val(16)Ala polymorphism and cancer risk have revealed inconsistent results. We conducted a meta-analysis on these studies. Our meta-analysis on total of 7,366 cancer cases and 9,102 controls from 13 published case-control studies showed no overall association of this polymorphism either with breast cancer risk or for cancer risk as such (for Ala homozygous odds ratio, 0.98; 95% confidence interval, 0.90-1.07 and odds ratio, 1.02; 95% confidence interval, 0.91-1.14, respectively). Also, there was no major effect in either recessive or dominant model for the MnSOD Val(16)Ala. However, a proper evaluation of this polymorphism with cancer link demands experiments involving large sample size, cross-tabulation of gene-gene, gene-environment interactions, and linkage studies, as cell biological experiments clearly correlate critical levels of mitochondrial O(*-)(2) and H(2)O(2) to carcinogenesis.

Age-dependent dichotomous effect of superoxide dismutase Ala16Val polymorphism on oxidized LDL levels

We investigated the association between superoxide dismutase (SOD) Ala16Val polymorphism and the levels of oxidized LDL lipoprotein-C (ox-LDL-C) in two age-different Greek cohorts. Four hundred fifteen middle-aged (n=147 females: 43.2+/-13 years, n=268 males: 43.3+/-14 years) Caucasian Greek subjects consisted the middle aged cohort. One hundred seventy five elderly (n=88 females: 79.9+/-4 years; n=87 males: 80.6+/-4 years) were selected from the elderly cohort. Genotype data were obtained for all of them. Multiple linear regression analysis, stratified by gender and adjusted for age, smoking habits and body mass index as covariates, showed higher ox-LDL-C levels for the middle aged men with the Val/Val genotype, compared to the other allele (Ala/Ala and Ala/Val) carriers (65.9+/-25.7 vs. 55.7+/-20.5 mg/dl; standardized beta coefficient=0.192, P=0.012). On the contrary, elderly women with the Val/Val genotype occurred with lower ox-LDL-C levels compared to the Ala/Ala or Ala/Val genotype (74.2+/-22.1 vs. 86.5+/-26.6 mg/dl; standardized beta coefficient= -0.269, P=0.015). The same trend was also recorded in elderly men, however without reaching statistical significance (standardized beta coefficient= -0.187, P=0.077). Moreover, elderly men and women with the Ala/Ala or Ala/Val genotype presented higher triglycerides levels compared to Val/Val (women: 145.2+/-68.7 vs. 114.3+/- 34.3 mg/dl, P= 0.027; men: 147.8+/-72.4 vs. 103.7 +/-38.0 mg/dl, P=0.002). Additionally, middle aged men with the Val/Val genotype had higher HDL-C levels compared to the Ala allele carriers. The results suggest that SOD Ala16Val polymorphism is an age-dependent modulator of ox-LDL-C levels in middle-aged men and elderly women.

Epithelium dysfunction in asthma

Although asthma is an inflammatory disorder of the conducting airways involving T(H)2-type T cells, there is increasing evidence for an important role played by the epithelium in orchestrating the inflammatory response by interacting with multiple environmental factors to produce a chronic wound scenario involving tissue injury and aberrant repair. Part of this abnormal response is the consequence of impaired barrier function caused by a primary disruption of epithelial tight junctions that allows inhaled substances to pass more easily into the airway wall to interact with immune and inflammatory cells. Aberrant communication between the damaged and stressed epithelium leads to the generation of growth factors that interact with the underlying mesenchyme to promote airway remodeling responses and a more chronic and persistent inflammatory phenotype. Disordered epithelial function with reduced antioxidant defense and impaired capacity to produce primary IFNs may also account for asthmatic susceptibility to air pollution and respiratory virus infection, respectively. Considering asthma as a disease of impaired barrier function opens new opportunities for therapeutic intervention or prevention by agents that could increase the airways resistance to the inhaled environment rather than suppressing the immune or inflammatory response.

Ozone, oxidant defense genes, and risk of asthma during adolescence

RATIONALE

Although oxidative stress is a cardinal feature of asthma, the roles of oxidant air pollutants and antioxidant genes heme oxygenase 1 (HMOX-1), catalase (CAT), and manganese superoxide dismutase (MNSOD) in asthma pathogenesis have yet to be determined.

OBJECTIVES

We hypothesized that the functional polymorphisms of HMOX-1 ([GT](n) repeat), CAT (-262C>T -844C>T), and MNSOD (Ala-9Val) are associated with new-onset asthma, and the effects of these variants vary by exposure to ozone, a potent oxidant air pollutant.

METHODS

We assessed this hypothesis in a population-based cohort of non-Hispanic (n = 1,125) and Hispanic white (n = 586) children who resided in 12 California communities and who were followed annually for 8 years to ascertain new-onset asthma.

MEASUREMENTS AND MAIN RESULTS

Air pollutants were continuously measured in each of the study communities during the 8 years of study follow-up. HMOX-1 "short" alleles (<23 repeats) were associated with a reduced risk for new-onset asthma among non-Hispanic whites (hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.41-0.99). This protective effect was largest in children residing in low-ozone communities (HR, 0.48; 95% CI, 0.25-0.91) (interaction P value = 0.003). Little evidence for an association with HMOX-1 was observed among Hispanic children. In contrast, Hispanic children with a variant of the CAT-262 "T" allele (CT or TT) had an increased risk for asthma (HR, 1.78; P value = 0.01). The effects of these polymorphisms were not modified by personal smoking or secondhand-smoke exposure.

CONCLUSIONS

Functional promoter variants in CAT and HMOX-1 showed ethnicity-specific associations with new-onset asthma. Oxidant gene protection was restricted to children living in low-ozone communities.

The relationship between polymorphisms in the glutamate cysteine ligase gene and asthma susceptibility

The present study was designed to investigate an association of common -588C/T and -23G/T polymorphisms within glutamate cysteine ligase modifier subunit gene with susceptibility to bronchial asthma. A total of 435 ethnically Russian subjects were recruited in this study, including 221 patients with asthma and 214 sex and age matched healthy subjects. As previously reported, the -588C/T and -23G/T polymorphisms were completely linked. The -588TT/-23TT genotype was found to be associated with decreased risk of allergic asthma after adjustment for age, gender and smoking status using multivariate logistic regression analysis (OR=0.33 95% CI 0.15-0.70, p=0.036). However, the -588CT/-23GT genotype was associated with increased risk of non-allergic asthma (OR=2.03 95% CI 1.05-3.90, p=0.06). This is a first study reporting the association between genetic variations in the glutamate cysteine ligase gene and susceptibility to bronchial asthma.