The signal sequence polymorphism of the MnSOD gene is associated with the degree of carotid atherosclerosis

Inflammation and Oxidative Stress Gene Variability in Retinal Detachment Patients with and without Proliferative Vitreoretinopathy

This study investigated the association between certain genetic variations and the risk of developing proliferative vitreoretinopathy (PVR) after surgery. The study was conducted on 192 patients with primary rhegmatogenous retinal detachment (RRD) who underwent 3-port pars plana vitrectomy (PPV). The distribution of single nucleotide polymorphisms (SNPs) located in genes involved in inflammation and oxidative stress associated with PVR pathways were analyzed among patients with and without postoperative PVR grade C1 or higher. A total of 7 defined SNPs of 5 genes were selected for genotyping: rs4880 (SOD2); rs1001179 (CAT); rs1050450 (GPX1); rs1143623, rs16944, rs1071676 (IL1B); rs2910164 (MIR146A) using competitive allele-specific polymerase chain reaction. The association of SNPs with PVR risk was evaluated using logistic regression. Furthermore, the possible association of SNPs with postoperative clinical parameters was evaluated using non-parametric tests. The difference between two genotype frequencies between patients with or without PVR grade C1 or higher was found to be statistically significant: SOD2 rs4880 and IL1B rs1071676. Carriers of at least one polymorphic IL1B rs1071676 GG allele appeared to have better postoperative best-corrected visual acuity only in patients without PVR (p = 0.070). Our study suggests that certain genetic variations may play a role in the development of PVR after surgery. These findings may have important implications for identifying patients at higher risk for PVR and developing new treatments.

Oxidative Stress Management in Cardiorenal Diseases: Focus on Novel Antidiabetic Agents, Finerenone, and Melatonin

Oxidative stress is characterized by excessive production of reactive oxygen species together with exhausted antioxidant defenses. This constitutes a main pathophysiologic process that is implicated in cardiovascular and renal diseases. In particular, enhanced oxidative stress may lead to low-density lipoprotein accumulation and oxidation, endothelial cell activation, adhesion molecule overexpression, macrophage activation, and foam cell formation, promoting the development and progression of atherosclerosis. The deleterious kidney effects of oxidative stress are numerous, including podocytopathy, mesangial enlargement, renal hypertrophy, tubulointerstitial fibrosis, and glomerulosclerosis. The prominent role of oxidative mechanisms in cardiorenal diseases may be counteracted by recently developed pharmacotherapies such as novel antidiabetic agents and finerenone. These agents have demonstrated significant antioxidant activity in preclinical and clinical studies. Moreover, the use of melatonin as a treatment in this field has been experimentally investigated, with large-scale clinical studies being awaited. Finally, clinical implications and future directions in this field are presented.

Effects of Altering Mitochondrial Antioxidant Capacity on Molecular and Phenotypic Drivers of Fibrocalcific Aortic Valve Stenosis

Background: While a small number of studies suggest that oxidative stress has an influential role in fibrocalcific aortic valve disease (FCAVD), the roles of specific antioxidant enzymes in progression of this disease remain poorly understood. Here, we focused on selectively altering mitochondrial-derived oxidative stress—which has been shown to alter progression of a myriad of age-associated diseases—on the progression of molecular and phenotypic drivers of FCAVD.

Methods: We generated low-density lipoprotein receptor-deficient, Apolipoprotein B100-only mice (LA) that were either haploinsufficient for MnSOD (LA-MnSOD^+/−) or genetically overexpressing MnSOD (LA-MnSOD^Tg/0). After 6 months of Western diet feeding, mice underwent echocardiography to assess valvular and cardiac function and tissues were harvested. Quantitative-RT PCR, immunohistochemistry, and histopathology were used to measure changes in molecular pathways related to oxidative stress, calcification, and fibrosis.

Results: While reductions in MnSOD increased oxidative stress, there was not an overt phenotypic effect of MnSOD deficiency on valvular and cardiac function in LA-MnSOD^+/− mice. While markers of canonical bone morphogenetic protein signaling tended to increase in valve tissue from LA-MnSOD^+/− (e.g., p-SMAD1/5/8 and osterix), we did not observe statistically significant increases in osteogenic signaling. We did, however, observe highly significant reductions in expression of osteopontin, which were associated with significant increases in calcium burden in LA-MnSOD^+/− mice. Reciprocally, genetically increasing MnSOD did not preserve valve function in LA-MnSOD^Tg/0, but we did observe slight reductions in p-SMAD1/5/8 levels compared to their non-transgenic littermates. Interestingly, overexpression of MnSOD dramatically increased expression of osteopontin in valve tissue from LA-MnSOD^Tg/0 mice, but was not sufficient to attenuate calcium burden when compared to their LA-MnSOD^0/0 littermates.

Conclusions: Collectively, this study demonstrates that maintenance of mitochondrial antioxidant capacity is important in preventing accelerated disease progression in a mouse model of FCAVD, but that effectively altering mitochondrial antioxidant capacity as a monotherapeutic approach to slow key histopathological and molecular drivers of FCAVD remains biologically and therapeutically challenging.

SOD1, more than just an antioxidant

During cellular respiration, radicals, such as superoxide, are produced, and in a large concentration, they may cause cell damage. To combat this threat, the cell employs the enzyme Cu/Zn Superoxide Dismutase (SOD1), which converts the radical superoxide into molecular oxygen and hydrogen peroxide, through redox reactions. Although this is its main function, recent studies have shown that the SOD1 has other functions that deviates from its original one including activation of nuclear gene transcription or as an RNA binding protein. This comprehensive review looks at the most important aspects of human SOD1 (hSOD1), including the structure, properties, and characteristics as well as transcriptional and post-translational modifications (PTM) that the enzyme can receive and their effects, and its many functions. We also discuss the strategies currently used to analyze it to better understand its participation in diseases linked to hSOD1 including Amyotrophic Lateral Sclerosis (ALS), cancer, and Parkinson.

Riding the tiger - physiological and pathological effects of superoxide and hydrogen peroxide generated in the mitochondrial matrix

Elevated mitochondrial matrix superoxide and/or hydrogen peroxide concentrations drive a wide range of physiological responses and pathologies. Concentrations of superoxide and hydrogen peroxide in the mitochondrial matrix are set mainly by rates of production, the activities of superoxide dismutase-2 (SOD2) and peroxiredoxin-3 (PRDX3), and by diffusion of hydrogen peroxide to the cytosol. These considerations can be used to generate criteria for assessing whether changes in matrix superoxide or hydrogen peroxide are both necessary and sufficient to drive redox signaling and pathology: is a phenotype affected by suppressing superoxide and hydrogen peroxide production; by manipulating the levels of SOD2, PRDX3 or mitochondria-targeted catalase; and by adding mitochondria-targeted SOD/catalase mimetics or mitochondria-targeted antioxidants? Is the pathology associated with variants in SOD2 and PRDX3 genes? Filtering the large literature on mitochondrial redox signaling using these criteria highlights considerable evidence that mitochondrial superoxide and hydrogen peroxide drive physiological responses involved in cellular stress management, including apoptosis, autophagy, propagation of endoplasmic reticulum stress, cellular senescence, HIF1α signaling, and immune responses. They also affect cell proliferation, migration, differentiation, and the cell cycle. Filtering the huge literature on pathologies highlights strong experimental evidence that 30-40 pathologies may be driven by mitochondrial matrix superoxide or hydrogen peroxide. These can be grouped into overlapping and interacting categories: metabolic, cardiovascular, inflammatory, and neurological diseases; cancer; ischemia/reperfusion injury; aging and its diseases; external insults, and genetic diseases. Understanding the involvement of mitochondrial matrix superoxide and hydrogen peroxide concentrations in these diseases can facilitate the rational development of appropriate therapies.

Superoxide imbalance triggered by Val16Ala-SOD2 polymorphism increases the risk of depression and self-reported psychological stress in free-living elderly people

BACKGROUND

Oxidative stress and chronic inflammatory states triggered by a single-nucleotide polymorphism (SNP) in superoxide dismutase manganese-dependent gene (Val16Ala-SOD2) have been associated with the risk of developing several chronic, nontransmissible diseases. However, it is still not clear whether the VV-SOD2 genotype that causes higher basal superoxide anion levels has any impact on the risk for depression and self-reported psychological stress in elderly people.

METHODS

In the present study, we tested this hypothesis using a case-control study where depression was detected using the Geriatric Depression Scale-15 (GDS-15). A total of 612 Brazilian free-living elderly subjects with a mean age of 67.1 ± 7.1 years old (number of controls, C = 497, and depressive individuals, D = 115) were included in this study. All participants had similar social, health, and lifestyle variables, with the exception of polypharmacy (≥5 medicines daily intake), which was higher in the D group, compared to C subjects.

RESULTS

Our results showed that the VV-SOD2 genotype significantly increased the risk for depression and psychological stress in the elderly subjects, independently of sex/gender, age, and other prior diseases and health indicators (depression risk = 1.842, 1.109-3.061 95% CI, p = .018). VV-subjects also had a higher daily intake of antidepressants, anxiolytics, and anti-inflammatory drugs than A-allele subjects.

CONCLUSION

Our findings support the hypothesis that genetically induced oxidative superoxide-hydrogen peroxide imbalance may be involved in an increased risk for developing depression and psychological stress in free-living elderly people without other chronic nontransmissible diseases.

Association between Polymorphisms of Antioxidant Gene (MnSOD, CAT, and GPx1) and Risk of Coronary Artery Disease

Objective

Reactive oxygen species (ROS) been cited as one of the major causes of atherosclerosis and coronary artery disease which are possible agents inducing DNA damage. Manganese superoxide dismutase (MnSOD), catalase (CAT), and glutathione peroxidase-1 (GPx1) have evolved to address primary defense against free radical mediated damage in mitochondria. The aim of this study was to delineate the association of MnSOD, CAT, and GPx1 polymorphisms and risk of CAD in Taiwan.

Methods

We conducted a case-control study with 657 participants recruited at a medical center. All subjects were evaluated by noninvasive stress test and then quantitative coronary angiography to confirm the diagnosis of CAD. 447 CAD cases were defined as >50% stenosis of coronary artery and 210 controls were stenosed below 50%. Polymorphisms of MnSOD (Val16Ala), CAT (C-262T), and GPx1 (Pro198Leu) genes were determined by polymerase chain reaction methods. Multivariate logistic regression model was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs).

Results

The MnSOD Val/Ala+Ala/Ala genotype was significantly associated with an increased risk of CAD compared to the Val/Val genotype (OR = 1.86, 95% CI = 1.15-3.01). This polymorphism was also associated with the severity of CAD of single and two vessel diseases. The corresponding ORs were 2.31 (95% CI = 1.32-4.03) and 1.92 (95% CI = 1.02-3.61), respectively. Among cigarette smokers, the harmful genetic effect of MnSOD Ala allele on CAD risk was much higher (OR = 2.23, 95% CI = 1.02-4.88). However, the interaction between MnSOD genotype and cigarette smoking on CAD risk was not significant. No significant association between CAT and GPx1 polymorphisms and CAD risk was observed.

Conclusion

Our results suggest that MnSOD polymorphism is an independent risk factor for susceptibility to CAD in the Chinese population.

The investigation of alfaalfa effect on the activity of superoxide dismutase in chicken meat in dependence on time storage

This study was conducted in order to monitor the effect of adding lucerne meal to chicken feed mixtures. The experiment was conducted at the Department Food Hygiene and Safety, Faculty of Biotechnology and Food Science, Slovak University of Agriculture in Nitra. Chickens for meat production - final type Cobb 500 were used in the experiment. Chickens were placed in boxes all together for one group at the beginning of the experiment and from 14 days of age chickens were divided individually into floor enriched cages. Feeding of chickens lasted 38 days. The experiment was carried out without sex segregation. For the production of a feed composition was used alfalfa (Medicago sativa) as lucerne meal, which was added to the feed at a rate of 4%, namely: starter (HYD-01), growth (HYD-02) and final (HYD-03). The control group did not include the addition of lucerne meal. Chickens were fed ad libitum. Chickens were slaughtered after completion of feeding and the meat samples were taken for analysis. The collected samples were stored at -18 °C. Collected samples of meat were analyzed after slaughter chickens at time intervals of 6, 12 and 18 months. In the experiment was monitored the content of supeoxid dismutase in the chicken meat depending on the length of storage time. Superoxide dismutase content was increasing by storage time, while there were some statistically significant differences between groups.

Roles of Vascular Oxidative Stress and Nitric Oxide in the Pathogenesis of Atherosclerosis

Major reactive oxygen species (ROS)–producing systems in vascular wall include NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase, xanthine oxidase, the mitochondrial electron transport chain, and uncoupled endothelial nitric oxide (NO) synthase. ROS at moderate concentrations have important signaling roles under physiological conditions. Excessive or sustained ROS production, however, when exceeding the available antioxidant defense systems, leads to oxidative stress. Animal studies have provided compelling evidence demonstrating the roles of vascular oxidative stress and NO in atherosclerosis. All established cardiovascular risk factors such as hypercholesterolemia, hypertension, diabetes mellitus, and smoking enhance ROS generation and decrease endothelial NO production. Key molecular events in atherogenesis such as oxidative modification of lipoproteins and phospholipids, endothelial cell activation, and macrophage infiltration/activation are facilitated by vascular oxidative stress and inhibited by endothelial NO. Atherosclerosis develops preferentially in vascular regions with disturbed blood flow (arches, branches, and bifurcations). The fact that these sites are associated with enhanced oxidative stress and reduced endothelial NO production is a further indication for the roles of ROS and NO in atherosclerosis. Therefore, prevention of vascular oxidative stress and improvement of endothelial NO production represent reasonable therapeutic strategies in addition to the treatment of established risk factors (hypercholesterolemia, hypertension, and diabetes mellitus).

The Impact of Superoxide Dismutase-1 Genetic Variation on Cardiovascular and All-Cause Mortality in a Prospective Cohort Study: The Yamagata (Takahata) Study

BACKGROUND

Oxidative stress is a major cause of cardiovascular disease. Superoxide dismutase-1 (SOD1) is an antioxidant that protects against oxidative stress. Deoxyribonucleic acid (DNA) variations such as single nucleotide polymorphism (SNP) or haplotypes within the SOD gene are reportedly associated with the development of cardiovascular disease. However, it remains to be determined whether SOD1 variability is associated with cardiovascular or all-cause mortality in the general population.

METHODS AND RESULTS

This prospective cohort study included 2799 subjects who participated in a community-based health study with a 10-year follow-up. We genotyped 639 SNPs and found the association of SNP rs1041740 and rs17880487 within a SOD1 gene with cardiovascular mortality. There were 193 deaths during the follow-up period including 57 cardiovascular deaths. Multivariate Cox proportional hazard regression analysis revealed that the homozygous T-allele of rs1041740 was associated with all-cause and cardiovascular deaths after adjusting for confounding factors. The net reclassification index was significantly improved by adding rs1041740 as a cardiovascular risk factor. On the other hand, cardiovascular death was not observed in homozygous T-allele carriers of rs17880487. Haplotype analysis identified the haplotype with T-allele of rs1041740 and that with T-allele of rs17880487 as increasing and decreasing susceptibility for cardiovascular mortality, and it had complementary SNP sequences.

CONCLUSION

Variation in the SOD1 gene was associated with cardiovascular deaths in the general population.

MnSOD and GPx1 polymorphism relationship with coronary heart disease risk and severity

BACKGROUND

Disturbance of the equilibrium between reactive oxygen species (ROS) and anti-oxidants (AOX) has been implicated in various diseases, including atherosclerosis, the most common pathologic process underlying coronary heart disease (CHD). Thus, the defense systems against ROS are critical protecting blood vessel walls against oxidative damage. In this study, we investigate whether Ala16Val MnSOD and Pro198Leu GPx polymorphisms are associated with CHD susceptibility and/or severity.

METHODS

Both polymorphisms were genotyped in a sample of 203 controls and 164 patients. CHD risk and severity, antioxidant status (enzymatic and/or non enzymatic) and biochemical parameters were assessed and analysed by genotype.

RESULTS

A significant association of MnSOD variant to CHD risk was revealed in males. Males harboring the Val/Val genotype were approximately at twofold increased risk of CHD compared to controls (Ala carriers vs Val/Val, adjusted OR 1.89; 95 % CI 1.18‒3.42, p = 0.03). Significant decreases in SOD activity and total antioxidant status (TAS) were observed in Val carriers and by CHD status. Whereas, no association of GPx variant genotype (Leu/Leu) and activity to cardiopathy events was discerned. CHD severity, as demonstrated by the number of vessel stenosis, was associated with significantly higher frequency of Val allele and LDL levels in CHD subjects.

CONCLUSIONS

Our results showed a lack of association of Pro198Leu GPx polymorphism to CHD risk and severity. However, they suggest that Ala16Val MnSOD polymorphism and decreased antioxidant defences are likely contributed to CHD risk in Tunisian men. Furthermore, the Val encoding MnSOD allele and decreased SOD activity were significantly correlated with CHD stenosis progression.

The effects of rosuvastatin on lipid-lowering, inflammatory, antioxidant and fibrinolytics blood biomarkers are influenced by Val16Ala superoxide dismutase manganese-dependent gene polymorphism

Rosuvastatin is a cholesterol-lowering drug that also attenuates the inflammatory process and oxidative stress via the reduction of superoxide anion production. Superoxide anions are metabolized by manganese-dependent superoxide dismutase (MnSOD or SOD2) in the mitochondria. In humans, there is a gene polymorphism where a change of alanine (Ala) to valine (Val) occurs at the 16th amino acid (Ala16Val-SOD2). The VV genotype has been associated with the risk of developing several metabolic diseases, such as hypercholesterolemia. Thus, to further explore this phenomenon, this study investigated the influence of the Val16Ala-SOD2 polymorphism on the lipid profile and inflammatory and fibrinolytic biomarkers of 122 hypercholesterolemic patients undergoing the first pharmacological cholesterol-lowering therapy who were treated with 20 mg rosuvastatin for 120 days. The findings indicate that the VV patients who present a low-efficiency SOD2 enzyme exhibit an attenuated response to rosuvastatin compared with the A-allele patients. The effect of rosuvastatin on inflammatory and fibrinolytic biomarkers was also less intense in the VV patients. These results suggest some pharmacogenetic effects of Val16Ala-SOD2 in hypercholesterolemia treatment.

Interplay between Superoxide Dismutase, Glutathione Peroxidase, and Peroxisome Proliferator Activated Receptor Gamma Polymorphisms on the Risk of End-Stage Renal Disease among Han Chinese Patients

Background. Single nucleotide polymorphisms (SNPs) of antioxidants, including superoxide dismutase 2 (SOD2) and glutathione peroxidase 1 (GPX1), play an important role in the risk for cancer and metabolic disorders. However, little is known regarding the effect of antioxidant SNPs on renal events. Methods. We prospectively enrolled multicenter patients with end-stage renal disease (ESRD) and those without chronic kidney disease (CKD) of Han Chinese origin, with SOD2 (Val16Ala), GPX1 (Pro197Leu), and PPAR-γ (Pro12Ala, C161T) genotyped. Multiple regression analyses were conducted to evaluate the significant risk determinants for ESRD. Results. Compared to ESRD patients, non-CKD subjects were more likely to have T allele at SOD2 Val16Ala (p = 0.036) and CC genotype at PPAR-γ Pro12Ala (p = 0.028). Regression analysis showed that TT genotype of SOD2 Val16Ala conferred significantly lower ESRD risk among patients without diabetes (odds ratio 0.699; p = 0.018). GPX1 SNP alone did not alter the risk. We detected significant interactions between SNPs including PPAR-γ Pro12Ala, C161T, and GPX1 regarding the risk of ESRD. Conclusion. This is the first and largest study on the association between adverse renal outcomes and antioxidant SNPs among Han Chinese population. Determination of SOD2 and PPAR-γ SNPs status might assist in ESRD risk estimation.

Association between genetic polymorphisms and carotid atherosclerosis in patients treated with radiotherapy for nasopharyngeal carcinoma

Background

Radiotherapy (RT) of the neck is commonly given to nasopharyngeal carcinoma (NPC) patients for preventing cervical lymph node metastasis. However, neck RT may induce the development of carotid atherosclerosis. The mechanisms of radiation-induced carotid atherosclerosis are still unclear and no previous study has investigated the genetic involvement of radiation-induced carotid atherosclerosis. The present study aims to determine the association between genetic polymorphisms and carotid atherosclerosis in patients treated with RT for nasopharyngeal carcinoma.

Methods

The present study recruited 128 post-RT NPC patients. Carotid plaque score was assessed using ultrasonography. Thirteen single nucleotide polymorphisms (SNPs) that affect the function of anti-atherosclerotic genes, including SOD2, SOD3, CAT, PON1, PPARG, ADIPOQ, IL10, TGFB1 and NOS3, were genotyped. Association between the 13 SNPs and carotid atherosclerosis was evaluated using multiple regression after adjustment for covariates (PLINK). Multiple testing was corrected using Benjamini-Hochberg step-up false discovery rate controlling procedure.

Results

rs662 and rs705379 of PON1 were close to be significantly associated with carotid plaque score (Corrected P value, P_cor = 0.0528 and P_cor = 0.0842). When the two SNPs were combined together, TC haplotype in rs662-rs705379 of PON1 was significantly associated with higher carotid plaque score (P_cor < 0.05). None of the other SNPs showed significant association with carotid plaque score.

Conclusions

TC haplotype in rs662-rs705379 of PON1 is likely to be a genetic risk factor of carotid plaque score. Post-RT NPC patients with the TC haplotype may need earlier and more frequent carotid ultrasound examinations for early detection of carotid atherosclerosis.

Manganese superoxide dismutase and oxidative stress modulation

Oxidative stress is characterized by imbalanced reactive oxygen species (ROS) production and antioxidant defenses. Two main antioxidant systems exist. The nonenzymatic system relies on molecules to directly quench ROS and the enzymatic system is composed of specific enzymes that detoxify ROS. Among the latter, the superoxide dismutase (SOD) family is important in oxidative stress modulation. Of these, manganese-dependent SOD (MnSOD) plays a major role due to its mitochondrial location, i.e., the main site of superoxide (O(2)(·-)) production. As such, extensive research has focused on its capacity to modulate oxidative stress. Early data demonstrated the relevance of MnSOD as an O(2)(·-) scavenger. More recent research has, however, identified a prominent role for MnSOD in carcinogenesis. In addition, SOD downregulation appears associated with health risk in heart and brain. A single nucleotide polymorphism which alters the mitochondria signaling sequence for the cytosolic MnSOD form has been identified. Transport into the mitochondria was differentially affected by allelic presence and a new chapter in MnSOD research thus begun. As a result, an ever-increasing number of diseases appear associated with this allelic variation including metabolic and cardiovascular disease. Although diet and exercise upregulate MnSOD, the relationship between environmental and genetic factors remains unclear.

Vascular oxidative stress, nitric oxide and atherosclerosis

In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxidation of tetrahydrobiopterin may cause eNOS uncoupling and thus potentiation of oxidative stress and reduction of eNOS-derived NO, which is a protective principle in the vasculature. This review summarizes the latest advances in the role of ROS-producing enzymes, antioxidative enzymes as well as NO synthases in the initiation and development of atherosclerosis.

Spontaneous abortion and functional polymorphism (Val16Ala) in the manganese SOD gene

Spontaneous abortion is the most common complication of early pregnancy. Genetic factors have been hypothesised to play a role in spontaneous abortion. Since it is possible that the balance of oxidants and antioxidants can be affected by different genetic variants, gene polymorphisms have been proposed as a susceptibility factor that increases the chance of miscarriage. Manganese superoxide dismutase is an important antioxidant enzyme encoded by manganese superoxide dismutase (MnSOD) gene. The aim of this experiment was to assess whether Val16Ala polymorphism of MnSOD gene is associated with miscarriage in northern Iran. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping. Statistical analyses were conducted using the χ(2)-test. The genetic distributions did not differ significantly between cases and controls, however slightly more Val/Val genotypes were found among the patients compared with control subjects (p = 0.059). No correlation was observed between susceptibility to abortion and MnSOD Val16Ala polymorphism. Larger population-based studies are needed for clarifying the relationship between abortion and MnSOD genotypes.

Reactive metabolites and antioxidant gene polymorphisms in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), by definition is a heterogeneous, multifactorial, polygenic syndrome which results from insulin receptor (IR) dysfunction. It is an outcome of oxidative stress caused by interactions of reactive metabolites (RMs) with lipids, proteins and other molecules of the human body. Production of RMs mainly superoxides (•O₂⁻) has been found in a variety of predominating cellular enzyme systems including nicotinamide adenine dinucleotide phosphate oxidase, xanthine oxidase, cyclooxygenase, endothelial nitric oxide synthase (eNOS) and myeloperoxidase. The four main RM related molecular mechanisms are: increased polyol pathway flux; increased advanced glycation end-product formation; activation of protein kinase C isoforms and increased hexosamine pathway flux which have been implicated in glucose-mediated vascular damage. Superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase and NOS are antioxidant enzymes involved in scavenging RMs in normal individuals. Functional polymorphisms of these antioxidant enzymes have been reported to be involved in the pathogenesis of T2DM. The low levels of antioxidant enzymes or their non-functionality results in excessive RMs which initiates stress related pathways thereby leading to IR and T2DM. An attempt has been made to review the role of RMs and antioxidant enzymes in oxidative stress resulting in T2DM.

The MnSOD Ala16Val SNP: relevance to human diseases and interaction with environmental factors

The relevance of reactive oxygen species (ROS) production relies on the dual role shown by these molecules in aerobes. ROS are known to modulate several physiological phenomena, such as immune response and cell growth and differentiation; on the other hand, uncontrolled ROS production may cause important tissue and cell damage, such as deoxyribonucleic acid oxidation, lipid peroxidation, and protein carbonylation. The manganese superoxide dismutase (MnSOD) antioxidant enzyme affords the major defense against ROS within the mitochondria, which is considered the main ROS production locus in aerobes. Structural and/or functional single nucleotide polymorphisms (SNP) within the MnSOD encoding gene may be relevant for ROS detoxification. Specifically, the MnSOD Ala16Val SNP has been shown to alter the enzyme localization and mitochondrial transportation, affecting the redox status balance. Oxidative stress may contribute to the development of type 2 diabetes, cardiovascular diseases, various inflammatory conditions, or cancer. The Ala16Val MnSOD SNP has been associated with these and other chronic diseases; however, inconsistent findings between studies have made difficult drawing definitive conclusions. Environmental factors, such as dietary antioxidant intake and exercise have been shown to affect ROS metabolism through antioxidant enzyme regulation and may contribute to explain inconsistencies in the literature. Nevertheless, whether environmental factors may be associated to the Ala16Val genotypes in human diseases still needs to be clarified.

Reactive metabolites and antioxidant gene polymorphisms in Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), by definition is a heterogeneous, multifactorial, polygenic syndrome which results from insulin receptor dysfunction. It is an outcome of oxidative stress caused by interactions of reactive metabolites (RMs) interactions with lipids, proteins and other mechanisms of human body. Production of RMs mainly superoxide (O2−) has been found in a variety of predominating cellular enzyme systems including NAD(P)H oxidase, xanthine oxidase (XO), cyclooxygenase (COX), uncoupled endothelial nitric oxide synthase (eNOS) and myeloperoxidase (MPO). The four main RM related molecular mechanisms are: increased polyol pathway flux; increased advanced glycation end-product (AGE) formation; activation of protein kinase C (PKC) isoforms and increased hexosamine pathway flux which have been implicated in glucose-mediated vascular damage. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), nitric oxide synthase (NOS) are antioxidant enzymes involved in scavenging RMs in normal individuals. Functional polymorphisms of these antioxidant enzymes have been reported to be involved in pathogenesis of T2DM individuals. The low levels of antioxidant enzymes or their non-functionality results in excessive RMs which initiate stress related pathways thereby leading to insulin resistance and T2DM. An attempt has been made to review the role of RMs and antioxidant enzymes in oxidative stress resulting in T2DM.

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Four main molecular mechanisms are implicated in glucose-mediated vascular damage.

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Impaired antioxidant defense contributes to T2DM and related complications.

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SNPs in antioxidant enzymes are associated with pathogenesis of type 2 diabetes.

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Genotyping of gene variants in populations will help identify individuals at risk.

Polymorphisms in the superoxidase dismutase genes reveal no association with human longevity in Germans: a case-control association study

The role of superoxide dismutases (SODs) in aging and oxidative stress regulation has been widely studied and there is growing evidence that imbalances in these processes influence lifespan in several species. In humans, genetic polymorphisms in SOD genes may play an important role in the development of age-related diseases and genetic variation in SOD2 is thought to be associated with longevity. These observations prompted us to perform a case-control association study using a comprehensive haplotype tagging approach for the three SOD genes (SOD1, SOD2, SOD3) by testing a total of 19 SNPs in our extensive collection of 1,612 long-lived individuals (centenarians and nonagenarians) and 1,104 younger controls. Furthermore, we intended to replicate the previous association of the SOD2 SNP rs4880 with longevity observed in a Danish cohort. In our study, no association was detected between the tested SNPs and the longevity phenotype, neither in the entire long-lived sample set nor in the centenarian subgroup analysis. Our results suggest that there is no considerable influence of sequence variation in the SOD genes on human longevity in Germans.

Polymorphisms in genes involved in oxidative stress response in patients with sudden sensorineural hearing loss and Ménière's disease in a Japanese population

The etiologies of idiopathic sudden sensorineural hearing loss (SSNHL) and Ménière's disease remain unclear. Recently, accumulating evidence has demonstrated that oxidative stress is related to the pathology of inner ear disease. Because genetic factors may contribute partly to the etiologies of SSNHL and Ménière's disease, we investigated the associations between genetic polymorphisms located in oxidative stress response genes and susceptibility to SSNHL and Ménière's disease. We compared 84 patients affected by SSNHL, 82 patients affected by Ménière's disease, and 2107 adults (1056 men and 1051 women; mean age, 59.2 years; range, 40-79 years) who participated in the National Institute for Longevity Sciences, Longitudinal Study of Aging. Multiple logistic regression was used to calculate odds ratios for SSNHL and Ménière's disease in individuals with polymorphisms in the genes glutathione peroxidase 1 (GPX1) (Pro198Leu, rs1050450), paraoxonase 1 (PON1) (Gln192Arg, rs662; and Met55Leu, rs854560), PON2 (Ser311Cys, rs7493), and superoxide dismutase 2 (SOD2) (Val16Ala, rs4880), with adjustment for age and gender. No significant differences in the distribution of the genotypes at these polymorphisms were observed among individuals with SSNHL and Ménière's disease and controls. No significant risk for SSNHL and Ménière's disease was observed in the additive genetic model, regardless of moderating variables. The C allele of SOD2 (rs4880) was more frequent in Ménière's disease cases with a hearing level over 50 dB compared with cases with a hearing level below 50 dB, suggesting that this polymorphism is associated with progression of a hearing loss in Ménière's disease. In conclusion, no significant associations between the polymorphisms of GPX1, PON1, PON2, and SOD2 and risk of SSNHL and Ménière's disease were observed in this Japanese case-control study.

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.

Clair DK. Manganese superoxide dismutase: guardian of the powerhouse

The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as β-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component.

Parameters of oxidative stress, DNA damage and DNA repair in type 1 and type 2 diabetes mellitus

OBJECTIVES

(i) to determine the extent of oxidative stress and DNA damage and repair using a panel of selected markers in patients with type 1 and type 2 diabetes mellitus (T1DM, T2DM), (ii) to find their possible relationships with diabetes compensation and duration, and finally (iii) to test for the effect of functional polymorphisms in the 8-oxoguanin DNA glycosylase (rs1052133), catalase (rs1001179) and superoxide dismutase (rs4880) genes on respective intermediate phenotypes.

METHODS

A total of 207 subjects (23 children and 44 adults with T1DM, 52 adult patients with T2DM and 88 healthy adult control subjects) were enrolled in the study. The following markers of redox state were determined in participants: erythrocyte superoxide dismutase (Ery-SOD), whole blood glutathione peroxidase (WB-GPx), erythrocyte glutathione (Ery-GSH), plasma total antioxidant capacity (P-tAOC) and plasma malondialdehyde (P-MDA). Furthermore, the extent of DNA damage and repair was ascertained using the following parameters: DNA single strand breaks (DNAssb), DNA repair capacity (DNArc) and DNA repair index (DNRI).

RESULTS

Comparison of T1DM vs. T2DM patients revealed significantly higher Ery-GSH content (P < 0.0001) and significantly lower Ery-SOD activity (P = 0.0006) and P-tAOC level (P < 0.0001) in T1DM subjects. T2DM diabetics exhibited a significant increase in DNAssb (P < 0.0001) and significant decrease in both DNArc (P < 0.0001) and DNRI (P <  .0001) compared with T1DM patients. Patient's age (irrespective of DM type) significantly correlated with DNAssb (r = 0.48, P < 0.0001), DNArc (r = -0.67, P < 0.0001) and DNRI (r = -0.7, P < 0.0001). Allele frequencies of all studied polymorphisms did not exhibit any significant association with the investigated parameters.

CONCLUSION

We demonstrated significant age- and DM type-related changes of oxidative DNA modification and capacity for its repair in subjects with T1DM and T2DM.

Chromium and manganese levels in biological samples of Pakistani myocardial infarction patients at different stages as related to controls

It has been speculated that trace elements may play a role in the pathogenesis of heart diseases In the present study, we aimed to access the levels of chromium (Cr) and manganese (Mn) in biological samples (whole blood, urine, and scalp hair) of myocardial infarction (MI) patients of both gender age ranged (45-60 years) at first, second, and third heart attack (n = 130), hospitalized in cardiac ward of National Hospital of Hyderabad city (Pakistan). For comparison, healthy age-matched referent subjects (n = 61), of both gender were also selected. The Cr and Mn in biological samples were measured by electrothermal atomic absorption spectrometry, prior to microwave-assisted acid digestion. The validity of the methodology was checked by the biological certified reference materials. During this study, 78% of 32 registered patients of third MI attack (aged >50 years) were died. In these subjects the concentration of Cr and Mn were decreased by 24.7% and 19.8% in scalp hair, while in blood samples 17.9% and 12.4%, respectively, as compared to those who tolerated third MI attack (p = 0.063). Although these data do not prove a causal relationship, these results are consistent with the hypothesis that heart disease may cause deficiencies of certain essential trace elements. The excretion levels of Cr and Mn in urine samples of first MCI were higher than controls at p values (0.029 and 0.011), respectively, whereas the excretion rates of both elements were further enhance after second myocardial infarction attack. The Cr and Mn concentration was inversely associated with the risk of myocardial infarction attacks in both genders. These results add to an increasing body of evidence that, Cr and Mn are importance for cardiovascular health.

Analysis of two polymorphisms of the manganese superoxide dismutase gene (Ile-58Thr and Ala-9Val) in patients with recurrent depressive disorder

Reactive oxygen species (ROS) may contribute to the pathogenesis of depressive disorder (DD). Functional genetic polymorphisms of manganese superoxide dismutase (MnSOD) are candidates for DD susceptibility. The study examined the relationship between MnSOD gene polymorphisms (Ala-9Val, Ile-58Thr) and DD in the Polish population. The association study was conducted in a case-control design in DD patients (n=149) and healthy controls (CG; n=149) by genotyping. Assessment of Ala-9Val genotype distribution and disease odds ratio demonstrated a statistically significant difference between the compared groups only in the female subgroup. The obtained results suggest a role of the MnSOD polymorphism in the development and course of depression.

Polymorphism (ALA16VAL) correlates with regional lymph node status in breast cancer

We studied the possible association between Ala16Val manganese-dependent superoxide dismutase (MnSOD) gene genotypes and breast cancer lymph node status because previous investigations suggested an association between the AA genotype and breast cancer. We included 281 women (188 controls and 93 cases of invasive breast cancer with axillary lymph node metastasis (LN+) and without lymph node metastasis (LN-). DNA was extracted from paraffin-embedded tumor tissue or peripheral blood leukocytes, and MnSOD polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism techniques. In addition, the immunohistochemical profile (p53, Ki-67 and estrogen/progesterone receptors) was also compared between invasive breast cancer groups and different MnSOD genotypes. The frequency of the VV genotype was higher in the LN+ group than in the control and LN- groups (chi(2)=5.081, P=0.02). Subjects with LN+ breast cancer (LN+ group) showed a higher incidence of VV genotype carriers associated with positive Ki-67 marker. Subjects with LN+ breast cancer (LN+ group) showed a higher incidence of VV genotype carriers associated with negative p53 marker. Despite the fact that the AA genotype is well established as being associated with an increased risk of breast cancer, the VV genotype may be associated with a higher metastatic potential, suggesting that MnSOD imbalance is the condition associated with carcinogenesis.

Oxidative risk for atherothrombotic cardiovascular disease

In the vasculature, reactive oxidant species, including reactive oxygen, nitrogen, or halogenating species, and thiyl, tyrosyl, or protein radicals may oxidatively modify lipids and proteins with deleterious consequences for vascular function. These biologically active free radical and nonradical species may be produced by increased activation of oxidant-generating sources and/or decreased cellular antioxidant capacity. Once formed, these species may engage in reactions to yield more potent oxidants that promote transition of the homeostatic vascular phenotype to a pathobiological state that is permissive for atherothrombogenesis. This dysfunctional vasculature is characterized by lipid peroxidation and aberrant lipid deposition, inflammation, immune cell activation, platelet activation, thrombus formation, and disturbed hemodynamic flow. Each of these pathobiological states is associated with an increase in the vascular burden of free radical species-derived oxidation products and, thereby, implicates increased oxidant stress in the pathogenesis of atherothrombotic vascular disease.

Association between manganese superoxide dismutase (MnSOD) gene polymorphism and elderly obesity

Evidence suggests an association between obesity and oxidative stress caused by superoxide production. Since the dismutation of superoxide is catalyzed by superoxide dismutase enzymes, we tested the association between obesity and Ala16Val manganese-dependent superoxide dismutase gene (MnSOD) polymorphism. We analyzed 815 free-living community subjects (> or =60 years old) grouped into subjects who were either obese (BMI > or = 30 kg/m(2)) or non-obese (BMI < 25 kg/m(2)). Additionally, we investigated the possible interaction between the Ala16Val MnSOD gene polymorphism and obesity in the modulation of biochemical and nutritional variables. We found a positive association between MnSOD polymorphism and obesity, since higher VV frequency (28.2%) was observed in the obese group (P = 0.002, odds ratio 1.949, 95% CI: 1.223-3.008). This result was independent of sex, age, diabetes, dyslipidemia, hypertension, and metabolic syndrome. A possible biological explanation of the association described here could be a chronic state of superoxide enzyme imbalance present in VV carriers, which could affect differential metabolic pathways contributing to the obese state.

The Mn-superoxide dismutase single nucleotide polymorphism rs4880 and the glutathione peroxidase 1 single nucleotide polymorphism rs1050450 are associated with aging and longevity in the oldest old

The free radical theory of aging states that reactive oxygen species (ROS) play a key role in age-related accumulation of cellular damage, and consequently influence aging and longevity. Therefore, variation in genes encoding proteins protecting against ROS could be expected to influence variation in aging and life span. The rs4880 and rs1050450 SNPs in the manganese superoxide dismutase (MnSOD) and glutathione peroxidase 1 (GPX1) genes, respectively, are associated with age-related diseases and appear to affect the activities of the encoded variant proteins. In this study we genotyped these SNPs in 1650 individuals from the Danish 1905 cohort (follow-up time: 1998-2008, age at intake: 92-93 years, number of deaths: 1589 (96.3%)) and investigated the association with aging and longevity. We found decreased mortality of individuals holding either the MnSOD rs4880 C or the GPX1 rs1050450 T alleles (HR (MnSOD(CC/CT))=0.91, P=0, p=0.002 and HR (GPX1(TT/TC))=0.93, p=0.008). Furthermore, a synergetic effect of the alleles was observed (HR=0.76, p=0.001). Finally, moderate positive associations with good self rated health, decreased disability and increased cognitive capacity were observed. Our results thus indicate that genetic variation in MnSOD and GPX1 may be associated with aging and longevity.

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.

Oxidative stress, endothelial dysfunction and cerebrovascular disease

Endothelial dysfunction is a marker of atherosclerosis and contributes to the atherogenic process and the development of atherothrombotic complications. Oxidative stress has been implicated in the development of endothelial dysfunction through alterations of the nitric oxide metabolism. A number of evidence suggests a role for phagocytic-cell-mediated oxidative stress in diminished nitric oxide availability that is present in patients with atherosclerotic risk factors such as arterial hypertension. Thus, the combination of an excessive production of reactive oxygen species, namely superoxide anion, with an impaired antioxidant defense capacity leading to oxidative stress may facilitate the development and progression of atherosclerosis. Findings from recent clinical studies suggest that this mechanism can be operative in patients with cerebrovascular disease. This view may increase our capabilities to understand the pathophysiology of cerebrovascular disease, as well as to stimulate the design of new therapeutic strategies aimed to prevent and control the atherosclerotic process in patients presenting this condition.

Manganese superoxide dismutase polymorphism affects the oxidized low-density lipoprotein-induced apoptosis of macrophages and coronary artery disease

AIMS

Oxidative damage promotes atherosclerosis. Manganese superoxide dismutase (MnSOD) is an antioxidant enzyme localized in mitochondria. We investigated the associations of the MnSOD polymorphism (valine-to-alanine in the mitochondrial-targeting domain) with its activity in leukocytes, with macrophage apoptosis by oxidized low-density lipoprotein (oxLDL), and with coronary artery disease (CAD).

METHODS AND RESULTS

Blood samples were taken from 50 healthy subjects. The mitochondrial MnSOD activities in leukocytes were 542.4 +/- 71.6 U/mg protein (alanine/alanine, n = 2), 302.0 +/- 94.9 U/mg protein (alanine/valine, n = 12), and 134.0 +/- 67.1 U/mg protein (valine/valine, n = 36; P < 0.0001 for non-valine/valine vs. valine/valine). Macrophages were treated with oxLDL. After incubation, the percentages of apoptotic macrophages were 48.6 +/- 3.6% (alanine/alanine), 78.6 +/- 9.8% (alanine/valine), and 87.5 +/- 7.0% (valine/valine) (P < 0.0001, non-valine/valine vs. valine/valine). The association of the MnSOD polymorphism with CAD was investigated using blood samples collected from 498 CAD patients and 627 healthy subjects; the alanine allele was found to reduce the risk of CAD and acute myocardial infarction (AMI).

CONCLUSION

Our data indicate that the alanine variant of signal peptide increases the mitochondrial MnSOD activity, protects macrophages against the oxLDL-induced apoptosis, and reduces the risk of CAD and AMI.

Manganese superoxide dismutase (Mn-SOD) gene polymorphisms in urolithiasis

Polymorphism in manganese superoxide dismutase gene (Mn-SOD) is a new approach to identify its probable association with urolithiasis. Oxidative stress may be involved in the development of stone formation in the renal system. MnSOD is one of the primary enzymes that directly scavenges potential harmful oxidizing species. A valine (Val) to alanine (Ala) substitution at amino acid 16, occurring in the mitochondrial targeting sequence of the MnSOD gene, has been associated with an increase in urolithiasis risk. This study was conducted to investigate the association of MnSOD gene polymorphism with the risk of urolithiasis. We investigated the MnSOD in 66 stone-forming adults and 72 healthy volunteers. DNA was isolated from peripheral blood and genotyping was performed with PCR-based methods. Then PCR products were cut by BsaW1. Products were run on 3% agarose gel, 246 bp regions were 1-Ala-9, 164 and 82 bp products were determined as 2 Val-9. Chi-square test was used for comparison between patients and controls. In the control group the homozygote Ala allele was significantly higher than in the patient group (P < 0.01). The distribution of Ala/Val and homozygote Val alleles in the patient group was significantly higher than in the control group (P < 0.05). MnSOD genotype determination may provide a tool to identify individuals who are at risk of urolithiasis. This experiment also provides data about antioxidant status and stone formation.

Polymorphisms and the expression of genes encoding enzymes involved in cardiovascular diseases

BACKGROUND

Atherosclerosis, a multi-factorial disease, is the main determinant of cardiovascular disease (CVD) leading to high mortality and morbidity in westernized countries. Gene polymorphisms and gene expression related to the atherosclerosis process can be identified using a genome-wide approach or looking for candidate disease-causing genes.

METHODS

Using genome wide strategy or candidate gene approach various genes, including paraoxonase genes, which are involved in lipid metabolism, oxidation, inflammation and coagulation, have been associated to atherosclerosis.

CONCLUSION

Evaluation of gene polymorphisms, together with traditional and novel biochemical parameters, may help identify individuals at a high risk for CVD. Genetic characterization of susceptibility genes may also lead to new drugs for atherosclerosis prevention and treatment. In addition, gene expression studies can provide novel insights into the molecular mechanism of lesion development and progression.

HFE gene mutations and oxidative stress influence serum ferritin, associated with vascular damage, in hemodialysis patients

BACKGROUND/AIMS

Hyperferritinemia has been associated with cardiovascular mortality in hemodialysis patients. The aim of this study was to evaluate whether serum ferritin was affected by iron and oxidative status and by genetic factors (HFE mutations and the Ala9Val MnSOD polymorphism), and to assess the association between ferritin and cardiovascular damage evaluated by ecocolor-Doppler.

METHODS

63 hemodialysis patients were tested for HFE and MnSOD genotype by restriction analysis and oxidative status; vascular damage was assessed by measuring intima-media thickness, and by detecting plaques at carotid and femoral arteries.

RESULTS

Ferritin was correlated with transferrin saturation (p = 0.003), decreased iron-specific serum antioxidant activity (p = 0.01), age (p = 0.03), and C282Y and H63D HFE mutations (p = 0.05), but not with the MnSOD polymorphism. Ferritin was associated with advanced vascular damage, as evaluated by the presence of plaques, both at carotid (p = 0.03) and femoral arteries (p = 0.001), the other risk factors being age and low albumin. Low iron-specific antioxidant activity was associated with carotid plaques (p = 0.03).

CONCLUSION

In hemodialysis patients, hyperferritinemia reflects a relative increase in iron availability and a decrease in iron-specific antioxidant activity, is favored by HFE mutations, and represents a risk factor for advanced cardiovascular damage.

Manganese superoxide dismutase polymorphism in chronic pelvic pain syndrome patients

Chronic pelvic pain syndrome (CPPS) is a common and serious health problem affecting the quality of life in men. In this study, we aim to investigate the manganese superoxide dismutase (MnSOD) polymorphism at nucleotide 47 as a result of the change of Ala to Val on the protein sequence in CPPS patients. The frequencies were 0.45 and 0.38 for the Ala and 0.55 and 0.62 for Val in National Institutes of Health category 3a and 3b groups. The differences between control and CPPS patients were statistically significant (P<0.05). However, frequencies recorded in 3a and 3b groups were not statistically different (P>0.05). Same results were obtained for enzyme analysis of MnSOD and glutathione peroxidase. Control group antioxidant enzyme levels were higher than patients' samples. The low antioxidant status of CPPS patients might be the clue for pathophysiological problems, and highly distributed Val allele frequency can be a mediator point of the illness. Our findings lead to the suggestion that oxidative disorder-linked medical health problems can be associated with genetic risk factors such as polymorphisms.

Activation of superoxide dismutases: putting the metal to the pedal

Superoxide dismutases (SOD) are important anti-oxidant enzymes that guard against superoxide toxicity. Various SOD enzymes have been characterized that employ either a copper, manganese, iron or nickel co-factor to carry out the disproportionation of superoxide. This review focuses on the copper and manganese forms, with particular emphasis on how the metal is inserted in vivo into the active site of SOD. Copper and manganese SODs diverge greatly in sequence and also in the metal insertion process. The intracellular copper SODs of eukaryotes (SOD1) can obtain copper post-translationally, by way of interactions with the CCS copper chaperone. CCS also oxidizes an intrasubunit disulfide in SOD1. Adventitious oxidation of the disulfide can lead to gross misfolding of immature forms of SOD1, particularly with SOD1 mutants linked to amyotrophic lateral sclerosis. In the case of mitochondrial MnSOD of eukaryotes (SOD2), metal insertion cannot occur post-translationally, but requires new synthesis and mitochondrial import of the SOD2 polypeptide. SOD2 can also bind iron in vivo, but is inactive with iron. Such metal ion mis-incorporation with SOD2 can become prevalent upon disruption of mitochondrial metal homeostasis. Accurate and regulated metallation of copper and manganese SOD molecules is vital to cell survival in an oxygenated environment.

Functional polymorphism in the manganese superoxide dismutase (MnSOD) gene in patients with asthma

OBJECTIVES

To investigate the possible association between functional variant Ala-9Val in the MnSOD gene and asthma in the case-control study comprising 626 Caucasian subjects.

METHODS

MnSOD genotypes were determined by PCR with subsequent restriction analysis by the BsaWI enzyme.

RESULTS

Significant differences in allele frequencies between groups were not ascertained.

CONCLUSIONS

Pursuant to these results, Ala-9Val polymorphism does not seem to be a significant predisposing factor for bronchial asthma in the Czech population.

Oxidative Enzymopathies and Vascular Disease

In the vasculature, reactive oxygen species (ROS) generated by both mitochondrial respiration and enzymatic sources serve as integral components of cellular signaling and homeostatic mechanisms. Because ROS are highly reactive biomolecules, the cellular redox milieu is carefully maintained by small-molecule antioxidants and antioxidant enzymes to prevent the deleterious consequences of ROS excess. When this redox balance is perturbed, because of either increased ROS production or decreased antioxidant capacity, oxidant stress is increased in the vessel wall and, if not offset, vascular dysfunction ensues. A number of heritable polymorphisms of pro-oxidant enzymes, including 5-lipoxygenase, cyclooxygenase-2, nitric oxide synthase-3, and NAD(P)H oxidase, have been identified and found to modulate ROS production and, thereby, the risk of atherothrombotic cardiovascular disease in individuals with these genetic polymorphisms. Similarly, heritable deficiency of the antioxidant enzymes catalase, glutathione peroxidases, glutathione- S -transferases, heme oxygenase, and glucose-6-phosphate dehydrogenase favors ROS accumulation, and has been associated with an increased risk of vascular disease. Individually, each of these polymorphisms imposes a state of uncompensated oxidant stress on the vasculature and collectively comprise the oxidative enzymopathies.

Genes and atherosclerosis: at the origin of the predisposition

Atherosclerosis (ATS) is a multifactorial disease caused by the interaction of established or emerging risk factors with multiple predisposing genes that regulate ATS-related processes. This review will discuss the current knowledge concerning the potential role of the genetic variations that could promote and/or accelerate ATS, in both animal models and humans. Allelic polymorphisms or variations of distinct genes that enhance the risk of ATS frequently occur in the general population, but only adequate gene-environment interactions will lead to the disease. The main genes so far studied are involved in the regulation of processes such as endothelial function, antioxidant potential, coagulation, inflammatory response, and lipid, protein and carbohydrate metabolism. The detection of candidate genes associated with ATS could allow, in the near future, earlier interventions in genetically susceptible individuals. Further, large-scale population studies are needed to obtain more information on the specific gene-environment and drug-gene interactions capable of influencing ATS progression.

Paraoxonase and superoxide dismutase gene polymorphisms and noise-induced hearing loss

BACKGROUND

Noise-induced cochlear epithelium damage can cause hearing loss in industrial workers. In experimental systems, noise induces the release of free radicals and may damage the cochlear sensorial epithelium. Therefore, genes involved in regulating the reactive oxygen species manganese-superoxide dismutase (SOD2) and the antioxidant paraoxonase (PON) could influence cochlea vulnerability to noise. We evaluated whether susceptibility to noise-induced hearing loss (NIHL) is associated with SOD2, PON1, and PON2 polymorphisms in workers exposed to prolonged loud noise.

METHODS

We enrolled 94 male workers from an aircraft factory in the study. The SOD2 gene was screened by denaturing reversed-phase HPLC, and the PON1 (Q192R and M55L) and PON2 (S311C) polymorphisms were analyzed by PCR amplification followed by digestion with restriction endonucleases.

RESULTS

Three known (A16V, IVS3-23T/G, and IVS3-60T/G) and two new SOD2 polymorphisms (IVS1+ 8A/G and IVS3+107T/A) were identified. Regression analysis showed that PON2 (SC+CC) [odds ratio (OR) = 5.01; 95% confidence interval (CI), 1.11-22.54], SOD2 IVS3-23T/G and IVS3-60T/G (OR = 5.09; 95% CI, 1.27-20.47), age (OR = 1.22; 95% CI, 1.09-1.36), and smoking (OR = 49.49; 95% CI, 5.09-480.66) were associated with NIHL. No association was detected for PON1 (QQ+RR) and PON1 (LL) genotypes.

CONCLUSIONS

Our data suggest that SOD2 and PON2 polymorphisms, by exerting variable local tissue antioxidant roles, could predispose to NIHL. However, caution should be exercised in interpreting these data given the small sample size and the difficulty in matching cases to controls regarding the overwhelming risk factor, i.e., smoking at least 10 cigarettes/day.

Genetics of Ultrasonographic Carotid Atherosclerosis

The search for genes related to the cause of common complex disorders such as cardiovascular disease has been frustrating, partly because of the many factors known to contribute to cardiovascular disease and the potential "distance" of cardiovascular disease as a phenotype from genes and gene products. Linkage and association studies for phenotypes more proximal in the pathway from DNA sequence variation to overt clinical disease, such as ultrasound-defined carotid atherosclerosis, may potentially be more enlightening. Only one genetic variant previously reported to be associated with atherosclerosis or clinically evident cardiovascular disease, matrix metalloproteinase (MMP) 3, has shown consistently positive associations with carotid disease, although it has not been studied widely. Another, PON1 L55M, is weakly associated in subgroups only, and 2, ApoE and MTHFR, are equivocal. Genetic variants reported to be associated with clinical cardiovascular disease show weak or no relationship to carotid atherosclerosis. This may reflect the known inconsistency in associations of genetic variants with clinical cardiovascular disease itself. Alternatively, genetic determinants of ultrasound-defined carotid atherosclerosis may differ from those of clinically manifest cardiovascular disease and may require pursuit through large-scale genomic studies of carotid atherosclerosis as a distinct phenotype. Only 1 genetic variant, MMP 3, has shown consistently positive associations with ultrasonographic carotid disease, although it has not been studied widely. Another, PON1 L55 mol/L, is weakly associated in subgroups only. Genetic variants reported to be associated with clinical cardiovascular disease show weak or no relationship to carotid atherosclerosis.