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

Association of functional superoxide gene polymorphism with chlamydia trachomatis-associated recurrent spontaneous abortion

BACKGROUND

Oxidative stress generated by Chlamydia trachomatis infection is associated with reproductive complications such as recurrent spontaneous abortion. Aim of prospective study was to evaluate whether single nucleotide polymorphisms (SNPs) of SOD1 and SOD2 gene are associated with C. trachomatis-infected recurrent spontaneous abortion (RSA).

METHODS

150 patients with history of RSA and 150 patients with history of successful deliveries were recruited from Department of Obstetrics and Gynecology, Safdarjung hospital, New Delhi, India. Urine and non-heparinized blood samples were collected and C. trachomatis was detected by polymerase chain reaction (PCR). Using qualitative real time PCR, SNPs rs4998557 (SOD1) and rs4880 (SOD2) were screened in enrolled patients. Level of 8-hydroxyguanosine (8-OHdG), 8-isoprostane (8-IP), progesterone and estrogen was determined by enzyme-linked immunosorbent assays and correlated with SNPs.

RESULTS

Significant differences were found in frequency of AA genotype of SOD1 gene among RSA patients versus controls, (82% and 54.66%, respectively; p = 0.02; OR 0.40; CI 95%). Frequency of AA genotype of SOD1 gene among RSA patients with C. trachomatis infection was 87.33%, while in uninfected RSA patients was 71.33% (p < 0.0001; OR 8; CI 95%). No significant relation was found between SOD2 (rs4880) genotype and RSA. Furthermore, significant increase in 8-OHdG, 8-IP and estrogen and significant decrease in progesterone was observed among patients carrying AA genotype.

CONCLUSIONS

Findings suggest the clinical importance of AA genotype along with 8-OHdG, 8-IP and estrogen and progesterone in screening C. trachomatis-infected RSA women.

Identification of molecular subtypes of ischaemic stroke based on immune-related genes and weighted co-expression network analysis

Immune system has been reported to play a key role in the development of ischaemic stroke (IS). Nevertheless, its exact immune-related mechanism has not yet been fully revealed. Gene expression data of IS and healthy control samples was downloaded from Gene Expression Omnibus database and differentially expressed genes (DEGs) was obtained. Immune-related genes (IRGs) data was downloaded from the ImmPort database. The molecular subtypes of IS were identified based on IRGs and weighted co-expression network analysis (WGCNA). 827 DEGs and 1142 IRGs were obtained in IS. Based on 1142 IRGs, 128 IS samples were clustered into two molecular subtypes: clusterA and clusterB. Based on the WGCNA, the authors found that the blue module had the highest correlation with IS. In the blue module, 90 genes were screened as candidate genes. The top 55 genes were selected as the central nodes according to gene degree in protein-protein interactions network of all genes in blue module. Through taking overlap, nine real hub genes were obtained that might distinguish between clusterA subtype and clusterB subtype of IS. The real hub genes (IL7R, ITK, SOD1, CD3D, LEF1, FBL, MAF, DNMT1, and SLAMF1) may be associated with molecular subtypes and immune regulation of IS.

Oxidative stress in cerebrovascular disease and associated diseases

Cellular aging is the most severe risk factor for neurodegenerative disease. Simultaneously, oxidative stress (OS) is a critical factor in the aging process, resulting from an imbalance between reactive oxygen and nitrogen species and the antioxidant defense system. Emerging evidence indicates that OS is a common cause of several age-related brain pathologies, including cerebrovascular diseases. Elevated OS disrupts endothelial functional ability by diminishing the bioavailability of nitric oxide (a vascular dilator), induces atherosclerosis, and impairs vasculature, which are all common characteristics of cerebrovascular disease. In this review, we summarize evidence supporting an active role of OS in cerebrovascular disease progression, focusing primarily on stroke pathogenesis. We briefly discuss hypertension, diabetes, heart disease, and genetic factors that are often linked to OS and are considered associated factors influencing stroke pathology. Finally, we discuss the current pharmaceutics/therapeutics available for treating several cerebrovascular diseases.

Association between lack of sexual interest and all-cause mortality in a Japanese general population: The Yamagata prospective observational study

BACKGROUND

Sexual interest is essential for maintaining positive sexual relationships and sexual function, which have recently been recognized as important indicators of good health and quality of life. Here, we prospectively investigated associations between sexual interest and mortality in a community-based population.

METHODS

This study enrolled 20,969 subjects (8,558 males and 12,411 females) aged ≥ 40 years who participated in annual health check-ups in Yamagata Prefecture. Sexual interest was assessed by a self-report questionnaire. Associations between sexual interest and increased all-cause mortality, cardiovascular disease mortality, and cancer mortality were investigated by Cox proportional hazards modeling.

RESULTS

During follow-up (median: 7.1 years), 503 subjects died; 67 deaths were due to cardiovascular disease, and 162 were due to cancer. Kaplan-Meier analysis showed that all-cause mortality and cancer mortality were significantly elevated among men who lacked sexual interest (log-rank P<0.0001, P<0.05). Cox proportional hazards model analysis with adjustment for age, hypertension, diabetes, dyslipidemia, smoking, alcohol drinking status, BMI, education, marital status, frequency of laughter, and psychological distress showed that the risk of all-cause mortality was significantly higher among men who lacked sexual interest than men who had sexual interest (hazard ratio [HR] 1.69; 95% confidence interval [CI], 1.17-2.44).

CONCLUSION

Lack of sexual interest is suggested to be a risk factor for all-cause mortality in Japanese males over 40 years old. This finding has implications for the importance of sexual interest in increasing longevity in this population.

Effects of Nitric Oxide Synthase 3 Gene Polymorphisms on Cardiovascular Events in a General Japanese Population ― The Yamagata (Takahata) Study ―

Background: Single nucleotide polymorphisms (SNPs) in nitric oxide synthase 3 (NOS3) are associated with cardiovascular risk factors. However, it is not clear whether the NOS3 SNP is a genetic risk factor for cardiovascular diseases.

Methods and Results: This prospective cohort study included 2,726 subjects aged ≥40 years who participated in a community-based health checkup. We genotyped 639 SNPs, including 2 NOS3 SNPs (rs1799983 and rs1808593). All subjects were monitored prospectively over a median follow-up period of 16.0 years, with the endpoint being cardiovascular events, including cardiovascular death and/or non-fatal myocardial infarction. Kaplan-Meier analysis demonstrated that both rs1799983 GT/TT and rs1808593 GG carriers had a higher risk of the endpoint than non-carriers. Univariate and multivariate Cox proportional hazard regression analyses revealed that both rs1799983 GT/TT and rs1808593 GG were independently associated with cardiovascular events after adjusting for confounding risk factors. The net reclassification index and integrated discrimination index were significantly improved by the addition of NOS3 SNPs as cardiovascular risk factors.

Conclusions:NOS3 gene polymorphisms could be genetic risk factors for cardiovascular events in the general Japanese population, and could be used to facilitate the early identification of individuals at high risk of cardiovascular events.

An assessment of the rescue action of resveratrol in parkin loss of function-induced oxidative stress in Drosophila melanogaster

Loss-of-function mutations in parkin is associated with onset of juvenile Parkinson's disease (PD). Resveratrol is a polyphenolic stilbene with neuroprotective activity. Here, we evaluated the rescue action of resveratrol in parkin mutant D. melanogaster. The control flies (w1118) received diet-containing 2% ethanol (vehicle), while the PD flies received diets-containing resveratrol (15, 30 and 60 mg/kg diet) for 21 days to assess survival rate. Consequently, similar treatments were carried out for 10 days to evaluate locomotor activity, oxidative stress and antioxidant markers. We also determined mRNA levels of Superoxide dismutase 1 (Sod1, an antioxidant gene) and ple, which encodes tyrosine hydroxylase, the rate-limiting step in dopamine synthesis. Our data showed that resveratrol improved survival rate and climbing activity of PD flies compared to untreated PD flies. Additionally, resveratrol protected against decreased activities of acetylcholinesterase and catalase and levels of non-protein thiols and total thiols displayed by PD flies. Moreover, resveratrol mitigated against parkin mutant-induced accumulations of hydrogen peroxide, nitric oxide and malondialdehyde. Resveratrol attenuated downregulation of ple and Sod1 and reduction in mitochondrial fluorescence intensity displayed by PD flies. Overall, resveratrol alleviated oxidative stress and locomotor deficit associated with parkin loss-of-function mutation and therefore might be useful for the management of PD.

Circadian Clock Gene Polymorphisms and Sleep-Onset Problems in a Population-Based Cohort Study: The Yamagata Study

A number of genome-wide association studies have investigated sleep phenotypes and disorders in humans. However, the contribution of genetic variation to sleep problems in Japanese populations has remained unclear. Sleep-onset problems are the most common symptom of insomnia. Here, we examined the relationship between single nucleotide polymorphisms (SNPs) of BMAL1 (ARNTL1), CLOCK, CRY1, CRY2, and PER2, which are genes involved in the clock mechanism, and sleep-onset problems in a Japanese general population. This study included 1,397 subjects aged ≥ 40 years who participated in an annual health check-up in Yamagata Prefecture. A total of 80 SNPs of 5 circadian clock genes were analyzed. Multivariate logistic regression analyses identified variant rs11113179 in CRY1 and variants rs1026071 and rs1562438 in BMAL1 as genetic risk factors for sleep induction disorder. These findings suggest that CRY1 and BMAL1 polymorphisms are related to sleep-onset problems in a Japanese general population. However, none of the SNPs remained significant at a stringent level of multiple correction.

Association of Nephronophthisis 4 genetic variation with cardiorenal syndrome and cardiovascular events in Japanese general population: the Yamagata (Takahata) study

BACKGROUND

Nephronophthisis (NPHP) 4 gene encoding nephrocystin-4, which contributes to end-stage renal disease in children and young adults, is involved in the development of the heart and kidneys. Cardiorenal syndrome (CRS), which consists of bidirectional dysfunction of the heart and kidneys, is a risk factor for cardiovascular events. Single-nucleotide polymorphisms (SNPs) within the NPHP4 gene are reportedly associated with kidney function, even in adults. However, the association of NPHP4 gene variability with CRS and cardiovascular events remains unknown.

METHODS AND RESULTS

This prospective cohort study included 2946 subjects who participated in a community-based health study with a 16-year follow-up period. We genotyped 11 SNPs within the NPHP4 gene whose minor allele frequency was greater than 0.1 in the Japanese population. The SNP rs12058375 was significantly associated with CRS and cardiovascular events. Multivariate logistic analysis demonstrated a significant association between the homozygous A-allele of rs12058375 with the presence of CRS. Haplotype analysis identified the haplotype with the A-allele of rs12058375 as an increased susceptibility factor for CRS. Kaplan-Meier analysis demonstrated that homozygous A-allele carriers of rs12058375 had the greatest risk of developing cardiovascular events among the NPHP4 variants. Multivariate Cox proportional hazard regression analysis revealed that the homozygous A-allele and heterozygous carriers of rs12058375 were associated with cardiovascular events after adjusting for confounding factors. The net reclassification index and integrated discrimination index were significantly improved by the addition of rs12058375 as a cardiovascular risk factor.

CONCLUSION

Genetic variations in the NPHP4 gene were associated with CRS and cardiovascular events in the general population, suggesting that it may facilitate the early identification of high-risk subjects with CRS and cardiovascular events.

Superoxide Dismutase Gene Polymorphism is Associated With Ischemic Stroke Risk in the China Dali Region Han Population

BACKGROUND

Stroke is a serious cardiovascular disease, a major cause of disability and death in both developed and developing countries. Superoxide dismutases (SODs) are enzymes that catalyze the breakdown of superoxide into oxygen and hydrogen peroxide and play a key role in the antioxidant response. This study explored the relationship between single-nucleotide polymorphisms (SNPs) in SOD genes and the risk of ischemic stroke (IS) in the Chinese Han population of Dali City.

METHODS

For this case-control study, the authors enrolled 144 patients who had an IS and 128 healthy controls. The SNPs rs17880487 and rs80265967 of the SOD1 gene, rs4880 and rs2842960 of the SOD2 gene, and rs2695232 and rs7655372 of the SOD3 gene were detected through TaqMan polymerase chain reaction. Genotypes and allele frequencies of the 2 groups were compared. Odds ratio and 95% confidence intervals were calculated by unconditional logistic regression, and environmental factors were corrected with multivariate logistic regression analysis.

RESULTS

Rs7655372 of SOD3 was associated with a significantly increased risk of IS. Moreover, the A and GA genotypes of SNP rs7655372 were associated with increased risk of IS, whereas the A and GA genotypes were risk factors for IS. Furthermore, multivariate logistic regression analysis showed that the rs7655372 GA genotype is the independent risk factor for IS.

CONCLUSION

The SOD3 gene rs7655372 locus polymorphism is a risk factor for IS in the Dali region.

Myocardial Hypertrophy and Compensatory Increase in Systolic Function in a Mouse Model of Oxidative Stress

Free radicals, or reactive oxygen species, have been implicated as one of the primary causes of myocardial pathologies elicited by chronic diseases and age. The imbalance between pro-oxidants and antioxidants, termed "oxidative stress", involves several pathological changes in mouse hearts, including hypertrophy and cardiac dysfunction. However, the molecular mechanisms and adaptations of the hearts in mice lacking cytoplasmic superoxide dismutase (Sod1KO) have not been investigated. We used echocardiography to characterize cardiac function and morphology in vivo. Protein expression and enzyme activity of Sod1KO were confirmed by targeted mass spectrometry and activity gel. The heart weights of the Sod1KO mice were significantly increased compared with their wildtype peers. The increase in heart weights was accompanied by concentric hypertrophy, posterior wall thickness of the left ventricles (LV), and reduced LV volume. Activated downstream pathways in Sod1KO hearts included serine-threonine kinase and ribosomal protein synthesis. Notably, the reduction in LV volume was compensated by enhanced systolic function, measured by increased ejection fraction and fractional shortening. A regulatory sarcomeric protein, troponin I, was hyper-phosphorylated in Sod1KO, while the vinculin protein was upregulated. In summary, mice lacking cytoplasmic superoxide dismutase were associated with an increase in heart weights and concentric hypertrophy, exhibiting a pathological adaptation of the hearts to oxidative stress.

Genetic polymorphisms of superoxide dismutase 1 are associated with the serum lipid profiles of Han Chinese adults in a sexually dimorphic manner

Inspired by the mechanistic correlations between superoxide dismutase 1 (SOD1) and lipid metabolism, the associations of SOD1 single nucleotide polymorphisms (SNPs) with circulating lipid levels were explored. In 2621 Chinese Han adults, randomly recruited from a health examination center without organic diseases, cancers, and pregnancy, three tag SNPs, rs4998557, rs1041740, and rs17880487 selected by Haploview software were genotyped with a probe-based real-time quantitative PCR method. In both genders, most parameters of the dyslipidemia adults were inferior (P < 0.001) to those of the non-dyslipidemia adults, and genotype frequencies of rs4998557 and rs17880487 were significantly different (P < 0.05) between the normal and abnormal subgroups of total cholesterol (TC) or high-density lipoprotein cholesterol (HDLC). Adjusted for confounding factors, logistic regression analyses revealed that in males rs4998557A, rs1041740T, and rs17880487T reduced the risk of high TC and/or LDLC (P < 0.05), and rs4998557A and rs17880487T increased the risk of low HDLC (P < 0.05); but in females, none of the SNPs had associations with any of the lipid parameters (P > 0.05). Conclusively, characterized by a sexual dimorphism, the SOD1 polymorphisms were associated with the lipid disorders in the adult males but not females of the Chinese Han population.

50 bp deletion in promoter superoxide dismutase 1 gene and increasing risk of cardiovascular disease in Mashhad stroke and heart atherosclerotic disorder cohort study

Cardiovascular disease (CVD), one of the main mortality causes worldwide is considered to be affected by general oxidative stress and inadequacy antioxidant system. Superoxide dismutase 1 (SOD1), a cytosolic antioxidant enzyme has a key role in neutralizing the excessive prooxidant by scavenging the super oxide anions. SOD1 polymorphic variants exhibit the altered activity properties. In the current study, we are aimed to investigate the association between the SOD1 polymorphism and CVD prevalence. A 6-years case control follow up study was designed to genotype the 526 participants (311 controls and 215 cases) for studying the 50 bp INS/DEL polymorphism at SOD1 promoter gene and analyze their blood lipid profile and anthropometric characteristics. Among the two possible alleles of the SOD1 gene (Wild [W] and Mutant [M]) the meaningful association was detected between the Mutants' frequency and the prevalence of CVD patients (p-value <.001). The W and M allele refer to inserted and deleted 50 bp in the polymorphic site of the SOD1 promoter, respectively. The WM and MM genotypes' frequency which indicate the wild heterozygotes and Mutant homozygotes, respectively, were significantly correlated with the prevalence of cardiovascular disease (p-value <.001). The present study has the potential to introduce the 50 bp INS/DEL polymorphism of SOD1 genotyping as a novel unique diagnostic approach for screening the high risk CVD.

Superoxide dismutase activity as a predictor of adverse outcomes in patients with nonischemic dilated cardiomyopathy

Oxidative stress contributes to progression of heart failure (HF). The present study analyzed the efficacy of the activities of superoxide dismutase (SOD) and its isoenzymes (CuZnSOD and MnSOD) as prognostic factors in dilated cardiomyopathy. The usefulness of activities of total SOD, MnSOD, and CuZnSOD was assessed, taking into account clinical, echocardiographic, and laboratory parameters as risk predictors of long-term clinical outcomes (death, heart transplant, combined end point) in 109 patients with nonischemic dilated cardiomyopathy (NIDCM) in this study with a 5-year follow-up. Regression analysis showed that total serum SOD activity was a predictor of worse long-term clinical outcome even after adjustment for NT-proBNP, hemoglobin, sodium, creatinine clearance, left ventricular ejection fraction (LVEF), BMI, and NYHA class (LVEF: HR 1.059, 95% CI 1.007-1.114, P = 0.026; BMI: HR 1.073, 95% CI 1.021-1.126, P = 0.005; NYHA: HR 1.073, 95% CI 1.022-1.126, P = 0.005). MnSOD and CuZnSOD activities were also predictors of worse long-term clinical outcome even after adjustment for laboratory parameters and BMI or NYHA class; however, after adjustment for LVEF, a borderline statistical significance was achieved (LVEF: HR 1.054, 95% CI 0.993-1.119, P = 0.081 [MnSOD]; HR 1.092, 95% CI 0.989-1.297, P = 0.082 [CuZnSOD]). Increased activities of total serum SOD and its isoenzymes in NIDCM patients correspond with a poor prognosis and may have prognostic value in the prediction of long-term clinical outcomes. In conclusion, the present study shows that serum SOD activity may be a useful predictor of adverse outcome in HF.

Associations between superoxide dismutase, malondialdehyde and all-cause mortality in older adults: a community-based cohort study

BACKGROUND

Oxidative stress is an important theory of aging but population-based evidence has been lacking. This study aimed to evaluate the associations between biomarkers of oxidative stress, including plasma superoxide dismutase (SOD) activity and malondialdehyde (MDA), with all-cause mortality in older adults.

METHODS

This is a community-based cohort study of 2224 participants (women:1227, median age: 86 years). We included individuals aged 65 or above and with plasma SOD activity and/or MDA tests at baseline. We evaluated the hazard ratios (HRs) and 95% confidence intervals (CIs) by multivariable Cox models.

RESULTS

We documented 858 deaths during six years of follow-up. There was a significant interaction effect of sex with the association between SOD activity and mortality (P < 0.001). Compared with the lowest quintile, the risk of all-cause mortality was inversely associated with increasing quintiles of plasma SOD activity in women(P-trend< 0.001), with adjusted HRs for the second through fifth quintiles of 0.73 (95% CI 0.53-1.02), 0.52(95% CI 0.38-0.72), 0.53(95% CI 0.39-0.73), and 0.48(95% CI 0.35-0.66). There were no significant associations between SOD activity and mortality in men (P-trend = 0.64), and between MDA and mortality in all participants (P-trend = 0.79).

CONCLUSIONS

Increased activity of SOD was independently associated with lower all-cause mortality in older women but not in men. This epidemiological study lent support for the free radical/oxidative stress theory of aging.

Erythrocyte SOD1 activity, but not SOD1 polymorphisms, is associated with ICU mortality in patients with septic shock

The objective of our study was to evaluate the influence of the superoxide dismutase 1 (SOD1) polymorphisms on erythrocyte SOD1 activity and the mortality of patients with septic shock. We prospectively evaluated 175 patients aged over 18 years with septic shock upon ICU admission. However, 38 patients were excluded. Thus, 137 patients were enrolled in the study. Blood samples were taken within the first 24 h of the patient's admission to determine erythrocyte SOD1 activity and nine SOD1 gene polymorphisms. The mean patient age was 63 ± 16 years, 58% were men, and ICU mortality rate was 66%. The patients who died were older and more severely ill, with higher Acute Physiology and Chronic Health Evaluation (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores, as well as higher lactate, urea, and protein carbonyl levels. In the logistic regression model, erythrocyte SOD1 activity was associated with ICU mortality. This relationship was also maintained in the highest tertile of SOD1 activity (odds ratio [OR]: 0.02; 95% confidence interval [CI]: 0.00-0.78; p = 0.037). Only SNP rs2070424 of the SOD1 gene influenced erythrocyte SOD1 activity. For patients with the AA allele, the activity of SOD1 was lower in relation to G-carriers (A/G+G/G genotype) (p = 0.019). None of the nine SOD1 SNPs were associated with ICU mortality. In conclusion, the SNP rs2070424 of the SOD1 gene interferes with erythrocyte SOD1 activity, and higher activity of SOD1 was associated with decreased mortality in patients with septic shock.

Influence of genetic variations in the SOD1 gene on the development of ascites and spontaneous bacterial peritonitis in decompensated liver cirrhosis

BACKGROUND

The balance between generation and elimination of reactive oxygen species by superoxide dismutase (SOD) is crucially involved in the pathophysiology of liver cirrhosis. Reactive oxygen species damage cells and induce inflammation/fibrosis, but also play a critical role in immune defense from pathogens. As both processes are involved in the development of liver cirrhosis and its complications, genetic variation of the SOD1 gene was investigated.

PATIENTS AND METHODS

Two SOD1 single nucleotide polymorphisms (rs1041740 and rs3844942) were analyzed in 49 cirrhotic patients undergoing liver transplantation. In addition, 344 cirrhotic patients with ascites were analyzed in a cohort of 521 individuals in terms of the relationship of these polymorphisms with spontaneous bacterial peritonitis (SBP).

RESULTS

Although rs3844942 showed no associations with complications of cirrhosis, we observed a significant association between rs1041740 and the presence of ascites and SBP in the discovery cohort of patients with cirrhosis. Importantly, the association with SBP was not confirmed in the validation cohort of patients with ascites. By contrast, a trend toward lower SBP rates was observed in carriers of rs1041740. In this cohort, rs1041740 was not associated with survival.

CONCLUSION

These data suggest a complex role of SOD1 in different processes leading to complications of liver cirrhosis. rs1041740 might be associated with the development of ascites and possibly plays a role in SBP once ascites has developed.