NAD(P)H oxidase polymorphism (C242T) and high HDL cholesterol associate with recurrent coronary events in postinfarction patients

ALOX5, LPA, MMP9 and TPO gene polymorphisms increase atherothrombosis susceptibility in middle-aged Mexicans

Atherothrombosis is the cornerstone of cardiovascular diseases and the primary cause of death worldwide. Genetic contribution to disturbances in lipid metabolism, coagulation, inflammation and oxidative stress increase the susceptibility to its development and progression. Given its multifactorial nature, the multiloci studies have been proposed as potential predictors of susceptibility. A cross-sectional study was conducted to explore the contribution of nine genes involved in oxidative stress, inflammatory and thrombotic processes in 204 subjects with atherothrombosis matched by age and gender with a healthy group (n = 204). To evaluate the possibility of spurious associations owing to the Mexican population genetic heterogeneity as well as its ancestral origins, 300 unrelated mestizo individuals and 329 Native Americans were also included. ALOX5, LPA, MMP9 and TPO gene polymorphisms, as well as their multiallelic combinations, were twice to four times more frequent in those individuals with clinical manifestations of atherothrombosis than in the healthy group. Once adjusting for population stratification was done, these differences remained. Our results add further evidence on the contribution of ALOX5, LPA, MMP9 and TPO polymorphisms to atherothrombosis development in the middle-aged group, emphasizing the multiethnic studies in search of gene risk polymorphisms.

Could high-density lipoprotein cholesterol predict increased cardiovascular risk?

PURPOSE OF REVIEW

Serum high-density lipoprotein (HDL) is considered to be protective against cardiovascular disease. However, there is emerging evidence that under certain conditions the HDL molecule can become dysfunctional and proinflammatory, paradoxically leading to increased risk of cardiovascular disease. This review will provide a brief outline of the potential mechanisms by which HDL can become atherogenic and summarize some of the clinical evidence on this topic.

RECENT FINDINGS

HDL metabolism, structure, and function in addition to its level can be profoundly altered under conditions of marked oxidative stress and chronic inflammation. These abnormalities, in turn, lead to impaired reverse cholesterol transport, increased systemic oxidative stress/inflammation, and endothelial dysfunction that subsequently may contribute to atherogenesis and progression of cardiovascular disease.

SUMMARY

Association of serum HDL cholesterol level with outcomes is not only dependent on its serum concentration but also on the qualities/properties of this lipoprotein at a given point in time. Hence, it is essential that future studies examining association of HDL with risk of cardiovascular disease take into account the complexities of HDL metabolism and function and address the impact of the HDL particle as a whole (quantity as well as various properties) on atherosclerosis and cardiovascular outcomes.

Influences on plasminogen activator inhibitor-2 polymorphism-associated recurrent cardiovascular disease risk in patients with high HDL cholesterol and inflammation

BACKGROUND AND AIMS

Evidence continues to accumulate that athero-protective effects of high-density lipoprotein (HDL) depend to some degree on effective HDL functionality and that such functionality can become degraded in the setting of chronic inflammation. To investigate this issue, we have studied a group of post-myocardial infarction patients with high levels of C-reactive protein as an indicator of chronic inflammation and with concurrently high levels of HDL cholesterol. For these patients we have demonstrated high-risk for recurrent cardiac events as well as a strong association of risk with a polymorphism of the gene (SERPINB2) for plasminogen activator inhibitor-2 (PAI-2) presumptively reflective of an important role for fibrinolysis in risk. However, additional processes might be involved. The current work sought to characterize processes underlying how PAI-2 might be involved in the generation of risk.

METHODS

Multivariate population data were leveraged using Bayesian network modeling, a graphical probabilistic approach for knowledge discovery, to generate networks reflective of influences on PAI-2 polymorphism-associated risk.

RESULTS

Modeling results revealed three individual networks centering on the PAI-2 polymorphism with specific features providing information relating to how the polymorphism might associate with risk. These included racial dependency, platelet clot initiation and propagation, oxidative stress, inflammation effects on HDL metabolism and coagulation, and induction and termination of fibrinolysis.

CONCLUSIONS

Beyond direct association of a PAI-2 polymorphism with recurrent risk in post-myocardial infarction patients, results suggest that PAI-2 likely plays a key role leading to risk through multiple pathophysiologic processes. Such knowledge could potentially be valuable with individualization of patient care.

Clinical Application of NOX Activity and Other Oxidative Biomarkers in Cardiovascular Disease: A Critical Review

SIGNIFICANCE

The oxidative stress theory of atherosclerosis is based on the assumption that the production of reactive oxidant species (ROS) by blood, as well as resident cells of the artery wall, elicits the formation of oxidized low-density lipoproteins (ox-LDL), which, in turn, promotes a series of inflammatory responses, ultimately leading to atherosclerotic plaque. This theory prompted the development of new laboratory methodologies that aimed at assessing the relationship between oxidative stress and clinical progression of human atherosclerosis.

CRITICAL ISSUES

Markers assessing the oxidation of phospholipid and protein components of LDL were among the first to be developed. Clinical trials included cross-sectional as well as retrospective and prospective studies that, however, provided equivocal results. Thus, clear evidence that oxidative biomarkers add more to the risk stratification by common atherosclerotic risk factors is still lacking.

RECENT ADVANCES

More recently, the analysis of oxidative stress focused on enzymatic pathways generating ROS, such as NADPH oxidase and myeloperoxidase (MPO). Experimental and clinical studies suggest that both enzymes may be implicated in promoting atherosclerotic disease. Novel laboratory methodologies have been, therefore, developed to study NADPH oxidase and MPO in patients with stable atherosclerosis as well as in patients with acute coronary and cerebro-vascular syndromes.

FUTURE DIRECTIONS

This review will analyze the strengths and weaknesses of the current methodology to study these enzymes in human atherosclerosis with particular regard to their clinical application in several settings of cardiovascular disease. Clinical methodology and results of previous studies with regard to markers of LDL oxidation have also been reviewed as a useful background for the future development of clinical trials.

Plasminogen activator inhibitor-2 polymorphism associates with recurrent coronary event risk in patients with high HDL and C-reactive protein levels

The objective of this work was to investigate whether fibrinolysis plays a role in establishing recurrent coronary event risk in a previously identified group of postinfarction patients. This group of patients was defined as having concurrently high levels of high-density lipoprotein cholesterol (HDL-C) and C-reactive protein (CRP) and was previously demonstrated to be at high-risk for recurrent coronary events. Potential risk associations of a genetic polymorphism of plasminogen activator inhibitor-2 (PAI-2) were probed as well as potential modulatory effects on such risk of a polymorphism of low-density lipoprotein receptor related protein (LRP-1), a scavenger receptor known to be involved in fibrinolysis in the context of cellular internalization of plasminogen activator/plansminogen activator inhibitor complexes. To this end, Cox multivariable modeling was performed as a function of genetic polymorphisms of PAI-2 (SERPINB, rs6095) and LRP-1 (LRP1, rs1800156) as well as a set of clinical parameters, blood biomarkers, and genetic polymorphisms previously demonstrated to be significantly and independently associated with risk in the study population including cholesteryl ester transfer protein (CETP, rs708272), p22phox (CYBA, rs4673), and thrombospondin-4 (THBS4, rs1866389). Risk association was demonstrated for the reference allele of the PAI-2 polymorphism (hazard ratio 0.41 per allele, 95% CI 0.20-0.84, p=0.014) along with continued significant risk associations for the p22phox and thrombospondin-4 polymorphisms. Additionally, further analysis revealed interaction of the LRP-1 and PAI-2 polymorphisms in generating differential risk that was illustrated using Kaplan-Meier survival analysis. We conclude from the study that fibrinolysis likely plays a role in establishing recurrent coronary risk in postinfarction patients with concurrently high levels of HDL-C and CRP as manifested by differential effects on risk by polymorphisms of several genes linked to key actions involved in the fibrinolytic process.

Association between NADPH oxidase p22(phox) C242T polymorphism and ischemic cerebrovascular disease: a meta-analysis

Background

Epidemiological studies have evaluated the association between nicotinamide adenine dinucleotide phosphate (NADPH) oxidase p22^phox C242T polymorphism and risk of ischemic cerebrovascular disease (ICVD), but the results remain inconclusive. This meta-analysis was therefore designed to clarify these controversies.

Methodology/Principal Findings

Systematic searches of electronic databases Embase, PubMed and Web of Science, as well as hand searching of the references of identified articles and the meeting abstracts were performed. Statistical analyses were performed using software Review Manager (Version 5.1.7) and Stata (Version 11.0). The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were performed. Fixed or random effects model was separately used depending on the heterogeneity between studies. Publication bias was tested by Begg's funnel plot and Egger's regression test. A total of 6 studies including 1,948 cases and 2,357 controls were combined showing no statistical evidence of association between NADPH oxidase p22^phox C242T polymorphism and overall ICVD (allelic model: OR = 1.08, 95%CI = 0.93–1.26; additive model: OR = 1.33, 95%CI = 0.81–2.17; dominant model: OR = 1.00, 95%CI = 0.86–1.15; recessive model: OR = 1.06, 95%CI = 0.77–1.45). Significant association was found in large-artery atherosclerotic stroke subgroup (allelic model: OR = 1.12, 95%CI = 0.88–1.41; additive model: OR = 1.36, 95%CI = 0.60–3.09; dominant model: OR = 1.25, 95%CI = 0.74–2.11; recessive model: OR = 2.17, 95%CI = 1.11–4.23). No statistical evidence of significant association was observed for small-vessel occlusive stroke, as well as Asian subgroup and Caucasian subgroup. Statistical powers on the combined sample size (total and subgroup) were all lower than 80%.

Conclusions/Significance

This meta-analysis indicates that NADPH oxidase p22^phox C242T polymorphism is more associated with large-artery atherosclerotic stroke than small-vessel occlusive stroke. However, this conclusion should be interpreted with caution due to the small sample size. Larger sample-size studies with homogeneous ICVD patients and well-matched controls are required.

Reactive Oxygen Species, SUMOylation, and Endothelial Inflammation

Although the exact mechanism through which NADPH oxidases (Nox's) generate reactive oxygen species (ROS) is still not completely understood, it is widely considered that ROS accumulation is the cause of oxidative stress in endothelial cells. Increasing pieces of evidence strongly indicate the role for ROS in endothelial inflammation and dysfunction and subsequent development of atherosclerotic plaques, which are causes of various pathological cardiac events. An overview for a causative relationship between ROS and endothelial inflammation will be provided in this review. Particularly, a crucial role for specific protein SUMOylation in endothelial inflammation will be presented. Given that SUMOylation of specific proteins leads to increased endothelial inflammation, targeting specific SUMOylated proteins may be an elegant, effective strategy to control inflammation. In addition, the involvement of ROS production in increasing the risk of recurrent coronary events in a sub-group of non-diabetic, post-infarction patients with elevated levels of HDL-cholesterol will be presented with the emphasis that elevated HDL-cholesterol under certain inflammatory conditions can lead to increased incidence of cardiovascular events.

Apolipoprotein E predicts incident cardiovascular disease risk in women but not in men with concurrently high levels of high-density lipoprotein cholesterol and C-reactive protein

Although there is great interest in the notion that dysfunctional transformation of high-density lipoprotein (HDL) facilitates development of atherosclerosis and cardiovascular disease (CVD), few studies in human populations directly address this issue. As apolipoprotein E (apoE) is a constituent of HDL thought to be important for HDL antiatherogenic function, we sought to assess the role of apoE in CVD risk in subjects likely to display dysfunctional transformation of HDL. Association of apoE levels with incident CVD risk was investigated using Cox multivariable proportional hazards modeling. Analyses were performed in subgroups of women and men likely to display dysfunctional transformation of HDL deriving from previous subgroup identification based upon defining characteristics of concurrently high levels of HDL cholesterol and systemic inflammation as reflected by high C-reactive protein levels. Results revealed apoE levels (dichotomized as highest quartile vs combined 3 lowest quartiles) as predicting subgroup risk in women (hazard ratio, 4.52; 95% confidence interval, 1.07-19.12; P = .040) but not in men. Further sex differences were manifested in terms of the relationship of apoE levels with age. Analysis revealed positive correlation of apoE levels with age in women (r = 0.47, P < .0001) but not in men (r = 0.04, P = .43). Apolipoprotein E levels predict incident CVD risk in women with high levels of HDL cholesterol and C-reactive protein but not in men. Future studies should be oriented toward investigations of apoE as related to multiplicity of HDL functionality and toward assessment of potential roles for apoE in dysfunctional transformation of HDL.

Apolipoprotein A-II influences apolipoprotein E-linked cardiovascular disease risk in women with high levels of HDL cholesterol and C-reactive protein

Background

In a previous report by our group, high levels of apolipoprotein E (apoE) were demonstrated to be associated with risk of incident cardiovascular disease in women with high levels of C-reactive protein (CRP) in the setting of both low (designated as HR1 subjects) and high (designated as HR2 subjects) levels of high-density lipoprotein cholesterol (HDL-C).

To assess whether apolipoprotein A-II (apoA-II) plays a role in apoE-associated risk in the two female groups.

Methodology/Principal

Outcome event mapping, a graphical data exploratory tool; Cox proportional hazards multivariable regression; and curve-fitting modeling were used to examine apoA-II influence on apoE-associated risk focusing on HDL particles with apolipoprotein A-I (apoA-I) without apoA-II (LpA-I) and HDL particles with both apoA-I and apoA-II (LpA-I:A-II). Results of outcome mappings as a function of apoE levels and the ratio of apoA-II to apoA-I revealed within each of the two populations, a high-risk subgroup characterized in each situation by high levels of apoE and additionally: in HR1, by a low value of the apoA-II/apoA-I ratio; and in HR2, by a moderate value of the apoA-II/apoA-I ratio. Furthermore, derived estimates of LpA-I and LpA-I:A-II levels revealed for high-risk versus remaining subjects: in HR1, higher levels of LpA-I and lower levels of LpA-I:A-II; and in HR2 the reverse, lower levels of LpA-I and higher levels of LpA-I:A-II. Results of multivariable risk modeling as a function of LpA-I and LpA-I:A-II (dichotomized as highest quartile versus combined three lower quartiles) revealed association of risk only for high levels of LpA-I:A-II in the HR2 subgroup (hazard ratio 5.31, 95% CI 1.12–25.17, p = 0.036). Furthermore, high LpA-I:A-II levels interacted with high apoE levels in establishing subgroup risk.

Conclusions/Significance

We conclude that apoA-II plays a significant role in apoE-associated risk of incident CVD in women with high levels of HDL-C and CRP.

Association between rs4673 (C/T) and rs13306294 (A/G) haplotypes of NAD(P)H oxidase p22phox gene and severity of stenosis in coronary arteries

Phagocytic NADH/NADPH oxidase is an important enzyme producing reactive oxygen species within subendothelial space of vessels. Findings have shown that p22phox subunit is an essential element related to the enzyme activity. Since some p22phox polymorphisms are thought to have functional roles in the enzyme thus, we studied the association between rs4673 (C242T) and rs13306294 (A/G) haplotypes and the severity of stenosis in coronary arteries. One hundred eighty-two subjects undergoing coronary angiography were recruited on the base of study design. Patients (n=114) had at least a stenosed coronary artery (>50% stenosis) and subdivided into three subgroups; SVD (n=28), 2VD (n=31) and 3VD (n=55) while controls (n=68) had the normal coronary arteries (<5% stenosis). The direct haplotyping technique of SNPs was performed using ARMS-RFLP-PCR method. Furthermore, alphabet-based tools predicted the changes of secondary structure at the rs4673 position. All haplotypes being proposed theoretically were found in the study population. The distribution of two-allele haplotypes had no significant difference between patients and controls (P=0.1). Although the rs4673 allele frequency was not significant between the groups (P>0.5), chi square test and multinomial regression analysis showed an observed high risk for rs13306294 A allele among patients. The bioinformatics tools predicted that the p22phox secondary structure is not changed due to the substitution of Tyr→His at the rs4673 position. We concluded that the polymorphisms have no allele linkage on the chromosome. In addition, the rs13306294 A allele is a potential factor of stenosis of coronary arteries that increases susceptibility for the extent of disease.

CYBA and GSTP1 variants associate with oxidative stress under hypobaric hypoxia as observed in high-altitude pulmonary oedema

HAPE (high-altitude pulmonary oedema) is characterized by pulmonary hypertension, vasoconstriction and an imbalance in oxygen-sensing redox switches. Excess ROS (reactive oxygen species) contribute to endothelial damage under hypobaric hypoxia, hence the oxidative-stress-related genes CYBA (cytochrome b-245 α polypeptide) and GSTP1 (glutathione transferase Pi 1) are potential candidate genes for HAPE. In the present study, we investigated the polymorphisms -930A/G and H72Y (C/T) of CYBA and I105V (A/G) and A114V (C/T) of GSTP1, individually and in combination, in 150 HAPE-p (HAPE patients), 180 HAPE-r (HAPE-resistant lowland natives) and 180 HLs (healthy highland natives). 8-Iso-PGF2α (8-iso-prostaglandin F2α) levels were determined in plasma and were correlated with individual alleles, genotype, haplotype and gene-gene interactions. The relative expression of CYBA and GSTP1 were determined in peripheral blood leucocytes. The genotype distribution of -930A/G, H72Y (C/T) and I105V (A/G) differed significantly in HAPE-p compared with HAPE-r and HLs (P≤0.01). The haplotypes G-C of -930A/G and H72Y (C/T) in CYBA and G-C and G-T of I105V (A/G) and A114V (C/T) in GSTP1 were over-represented in HAPE-p; in contrast, haplotypes A-T of -930A/G and H72Y (C/T) in CYBA and A-C of I105V (A/G) and A114V (C/T) in GSTP1 were over-represented in HAPE-r and HLs. 8-Iso-PGF2α levels were significantly higher in HAPE-p and in HLs than in HAPE-r (P=2.2×10(-16) and 1.2×10(-14) respectively) and the expression of CYBA and GSTP1 varied differentially (P<0.05). Regression analysis showed that the risk alleles G, C, G and T of -930A/G, H72Y (C/T), I105V (A/G) and A114V (C/T) were associated with increased 8-iso-PGF2α levels (P<0.05). Interaction between the two genes revealed over-representation of most of the risk-allele-associated genotype combinations in HAPE-p and protective-allele-associated genotype combinations in HLs. In conclusion, the risk alleles of CYBA and GSTP1, their haplotypes and gene-gene interactions are associated with imbalanced oxidative stress and, thereby, with high-altitude adaptation and mal-adaptation.

Thrombospondin-4 polymorphism (A387P) predicts cardiovascular risk in postinfarction patients with high HDL cholesterol and C-reactive protein levels

Few studies are available in human populations investigating involvement of vascular inflammation and oxidative stress-related dysfunctional transformation of high-density lipoprotein (HDL) in establishing cardiovascular disease (CVD) risk. To this end, the current work investigated a subgroup of post-infarction patients at high-risk for recurrent events defined by high levels of HDL cholesterol (HDL-C) and concurrently high levels of C-reactive protein (CRP). Thrombospondin-4 (TSP-4), a matricellular protein of vessel walls associated with inflammation, was investigated in terms of CVD risk using multivariable modelling with a well-characterised functional genetic polymorphism of THBS4 (A387P, rs1866389) along with previously demonstrated risk-related functional genetic polymorphisms of CYBA (C242T, rs4673) and CETP (TaqIB, rs708272), and a set of blood markers. Results revealed risk-association for the gain-of-function P-allele of the THBS4 polymorphism (hazard ratio 2.00, 95% confidence interval 1.10-3.65, p=0.024). Additionally, von Willebrand factor was associated with D-dimer levels in the higher-risk P allele patients suggestive of a connection between endothelial dysfunction and thrombogenesis. In conclusion, TSP-4, a matricellular protein involved in regulating vascular inflammation, plays a role in establishing recurrent coronary risk in post-infarction patients with high levels of HDL-C and CRP. Further studies should focus on additional effects of vascular inflammatory processes on anti-atherogenic functionality of HDL particles.

LPL polymorphism (D9N) predicts cardiovascular disease risk directly and through interaction with CETP polymorphism (TaqIB) in women with high HDL cholesterol and CRP

OBJECTIVE

We sought to determine whether concurrently high levels of HDL cholesterol and CRP predict initial cardiovascular events in women, and to assess additional risk involving two genes encoding proteins involved in reverse cholesterol transport.

METHODS

A graphical approach identified high-risk subgroups in a population-based female cohort. Polymorphism-associated risk was assessed for CETP (TaqIB [rs708272]) and LPL (D9N [rs1801177]) using multivariable analysis adjusted for clinical parameters and biomarkers.

RESULTS

A high HDL-C/high CRP high-risk subgroup was identified. Multivariable modeling revealed D9N as predicting subgroup cardiovascular disease risk directly (minor allele-carriers versus major allele homozygotes: HR 5.16, 95% CI 1.43-18.54, p = 0.012) and through interaction with TaqIB (highest risk in minor allele carriers of both polymorphisms).

CONCLUSIONS

In women with high HDL-C and high CRP levels, an LPL polymorphism associated with risk and interacted with a CETP polymorphism such that the highest risk occurred in subjects with presumably decreased activities of both proteins.

Friend Turns Foe: Transformation of Anti-Inflammatory HDL to Proinflammatory HDL during Acute-Phase Response

High-density lipoprotein (HDL) is a major carrier of cholesterol in the blood. Unlike other lipoproteins, physiological functions of HDL influence the cardiovascular system in favorable ways except when HDL is modified pathologically. The cardioprotective mechanism of HDL is mainly based on reverse cholesterol transport, but there has been an emerging interest in the anti-inflammatory and antioxidant roles of HDL. These latter activities of HDL are compromised in many pathological states associated with inflammation. Further, abnormal HDL can become proinflammatory contributing to oxidative damage. In this paper, we discuss the functional heterogeneity of HDL, how alterations in these particles in inflammatory states result in loss of both antioxidant activity and reverse cholesterol transport in relation to atherosclerosis, and the need for assays to predict its functionality.

Inflammation reduces HDL protection against primary cardiac risk

BACKGROUND

We recently reported high high-density lipoprotein (HDL) cholesterol as a predictor of recurrent risk in a subgroup of postinfarction patients defined by hypercholesterolemia and high C-reactive protein (CRP) levels. We investigated whether a similar high-risk subgroup might exist for incident cardiovascular disease.

MATERIAL AND METHODS

A graphical exploratory data analysis tool was used to identify high-risk subgroups in a male population-based cohort (n = 3405) from the prevention of renal and vascular end-stage disease study by generating 3-dimensional mappings of risk over the HDL-cholesterol/CRP domain with subsequent use of Kaplan-Meier analysis to verify high-risk. Within-subgroup risk was assessed using Cox proportional hazards regression and Kaplan-Meier analysis.

RESULTS

Mappings revealed two high-risk subgroups: a low HDL-cholesterol/high CRP subgroup and a high HDL-cholesterol/high CRP subgroup. The low HDL-cholesterol subgroup demonstrated a pattern of metabolic syndrome dyslipidemia contrasted with a predominantly unremarkable biomarker pattern for the high HDL-cholesterol subgroup. However, in the high HDL-cholesterol subgroup, CRP levels were higher than the low HDL-cholesterol subgroup; and within the high HDL-cholesterol subgroup, CRP predicted risk. Moreover, in the high HDL-cholesterol subgroup, risk was associated with lower triglyceride levels in conjunction with presumptively larger HDL particles.

CONCLUSIONS

High HDL-cholesterol and high CRP levels define a subgroup of men at high-risk for incident cardiovascular disease. High HDL cholesterol-associated risk likely relates to impaired HDL particle remodelling in the setting of inflammation. This approach may facilitate identification of additional inflammation-related mechanisms underlying high HDL cholesterol-associated risk; and potentially influence management of such patients.

Cholesteryl ester transfer protein polymorphism (TaqIB) associates with risk in postinfarction patients with high C-reactive protein and high-density lipoprotein cholesterol levels

OBJECTIVE

To investigate the roles of inflammation and a cholesteryl ester transfer protein (CETP) polymorphism potentially related to recent findings demonstrating coronary risk with increasing high-density lipoprotein cholesterol (HDL-C) level.

METHODS AND RESULTS

A novel graphical exploratory data analysis tool allowed the examination of coronary risk in postinfarction patients relating to HDL-C and C-reactive protein levels. Results demonstrated a high-risk subgroup, defined by high HDL-C and C-reactive protein levels, exhibiting larger HDL particles and lower lipoprotein-associated phospholipaseA(2) levels than lower-risk patients. Subgroup CETP-associated risk was probed using a functional CETP polymorphism (TaqIB, rs708272). In the high-risk subgroup, multivariable modeling revealed greater risk for B2 allele carriers (less CETP activity) versus B1 homozygotes (hazard ratio, 2.41; 95% CI, 1.04 to 5.60; P=0.04). Within the high-risk subgroup, B2 allele carriers had higher serum amyloid A levels than B1 homozygotes. Evidence also demonstrates that CETP genotypic differences in HDL subfraction distributions regarding non-HDL-C and lipoprotein-associated phospholipaseA(2) may potentially relate to impaired HDL remodeling.

CONCLUSIONS

Postinfarction patients with high HDL-C and C-reactive protein levels demonstrate increased risk for recurrent events. Future studies should aim at characterizing altered HDL particles from such patients and at elucidating the mechanistic details related to inflammation and HDL particle remodeling. Such patients should be considered in drug trials involving an increase in HDL-C level.

C242T Polymorphism of NADPH Oxidase p22phox and Recurrence of Cardiovascular Events in Coronary Artery Disease

Objectives— The common C242T polymorphism in the gene for the p22phox subunit of NADPH oxidase has been reported to be negatively associated with oxidative stress, but whether it confers prognostic information is not yet clear.

Methods and Results— The incidence of major adverse cardiovascular events (MACE) were determined in 237 patients with coronary stenosis during a median follow-up of 7.8 years. The p22phox genotypes were evaluated in 213 patients (89.9%) by polymerase chain reaction and Rsa I. digestion. Plasma levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a marker of oxidative stress, were also measured. In the univariate analysis, patients with CT/TT genotypes showed reduced recurrence of cardiovascular deaths, nonfatal MI, and revascularization procedures compared with homozygous carriers of the C allele. After controlling for confounders, a significantly lower risk of new revascularization procedures (HR=0.31, 95% CI 0.12 to 0.70; P =0.014) remained associated with the T allele. The Kaplan–Meier analysis showed a longer survival free from fatal and nonfatal MI in carriers of T allele ( P <0.001). The presence of the 242T allele was associated with significantly reduced plasma concentrations of 8-OHdG.

Conclusions— The 242T allele was a predictor of lower risk of recurrence of cardiovascular events in high-risk patients and was associated with reduced systemic oxidative stress.

NADPH oxidase CYBA polymorphisms, oxidative stress and cardiovascular diseases

Oxidative stress plays a key role in the pathophysiology of several major cardiovascular diseases, including atherosclerosis, hypertension, heart failure, stroke and diabetes. ROS (reactive oxygen species) affect multiple tissues either directly or through NO depletion. ROS induce cardiovascular dysfunction by modulating cell contraction/dilation, migration, growth/apoptosis and extracellular matrix protein turnover, which contribute to vascular and cardiac remodelling. Of the several sources of ROS within the cardiovascular system, a family of multisubunit NADPH oxidases appears to be a predominant contributor of superoxide anion. Recent findings suggest a significant role of the genetic background in NADPH oxidase regulation. Common genetic polymorphisms within the promoter and exonic sequences of CYBA, the gene that encodes the p22(phox) subunit of NADPH oxidase, have been characterized in the context of cardiovascular diseases. This review aims to present the current state of research into these polymorphisms in their relationship to cardiovascular diseases.