Association between myeloperoxidase polymorphisms and its plasma levels with severity of coronary artery disease

Genetic and clinical study of myeloperoxidase's association with coronary artery disease

BACKGROUND

Unraveling myeloperoxidase's (MPO) correlation with coronary artery disease (CAD) and genetic variations, this study seeks to enhance diagnostic precision and therapeutic strategies.

RESULTS

CAD patients were found to be older and more male than controls. Several clinical parameters, including glucose, total bilirubin, alkaline phosphatase, creatinine, and troponin levels, showed significant variations. Moreover, CAD patients had lower red cell distribution width (RDW%) and mean platelet volume (MPV) than controls. Serum MPO levels did not differ significantly between CAD patients and controls, and no correlation was found with other clinical parameters except for glucose, creatinine, and total bilirubin.

CONCLUSIONS

The data suggest that serum MPO levels are not substantially related to CAD patients, as indicated by lower MPO levels in CAD patients compared to controls. While highlighting the potential of MPV and RDW% as predictors of severe atherosclerosis in CAD. Further research is needed to validate the diagnostic and prognostic value of RDW%, MPV, and MPO levels in CAD.

TRIAL REGISTRATION

15092021-9-12. Registered 15 September 2021.

Free Radical Lipid Peroxidation Induced by Reactive Halogen Species

The review is devoted to the mechanisms of free radical lipid peroxidation (LPO) initiated by reactive halogen species (RHS) produced in mammals, including humans, by heme peroxidase enzymes, primarily myeloperoxidase (MPO). It has been shown that RHS can participate in LPO both in the initiation and branching steps of the LPO chain reactions. The initiation step of RHS-induced LPO mainly involves formation of free radicals in the reactions of RHS with nitrite and/or with amino groups of phosphatidylethanolamine or Lys. The branching step of the oxidative chain is the reaction of RHS with lipid hydroperoxides, in which peroxyl and alkoxyl radicals are formed. The role of RHS-induced LPO in the development of human inflammatory diseases (cardiovascular and neurodegenerative diseases, cancer, diabetes, rheumatoid arthritis) is discussed in detail.

Oxidative Stress Biomarkers in Coronary Artery Disease

Oxidative stress plays a central role in atherogenesis, implicated in endothelial dysfunction, coronary plaque formation, and destabilization. Therefore, identifying oxidative stress in the vascular wall by reliable biomarkers could aid in early diagnosis and better coronary artery disease (CAD) prognostication. Because of the short half-life of reactive oxygen species, the current approach is to measure stable products generated by the oxidation of macromolecules in plasma or urine. Most popular oxidative stress biomarkers are oxidized low-density lipoprotein, myeloperoxidase and lipid peroxidation biomarkers, such as malondialdehyde and F2-isoprostanes. Oxidative protein modification biomarkers and oxidized phospholipids have also been studied and discussed in the present review. Most of these biomarkers are associated with the presence and extent of CAD, are elevated in patients with acute coronary syndromes, and may predict outcomes independent of traditional CAD risk factors. However, further standardization of measurement methods and assessment in large randomized clinical trials are required to integrate these biomarkers into clinical practice. In addition, evidence that these biomarkers detect oxidative stress in the vascular wall lacks and more specific biomarkers should be developed to identify vascular oxidative stress. Consequently, several oxidative stress biomarkers have been developed, most of which can be associated with the presence and extent of CAD and event prognosis. However, they still have significant limitations that hinder their integration into clinical practice.

Serum Progranulin As a Risk Predictor in Patients with Acute Myocardial Infarction

BACKGROUND Although progranulin was recently proposed as an adipokine that may be involved in glucose metabolic and inflammatory diseases, the role of serum progranulin in cardiovascular disease is elusive and remains disputed. The aim of our research was to determine the concentration of serum progranulin in Chinese patients with cardiovascular disease, notably in acute myocardial infarction (AMI), and its relationship to other cardiometabolic risk factors. MATERIAL AND METHODS This prospective observational study included 342 Chinese AMI patients and 255 healthy control subjects. Serum progranulin concentrations and various cardiometabolic risk factor levels were investigated. We assessed the relationship between progranulin and other cardiometabolic risk factors. Logistic regression analysis was applied to evaluate risk factors in patients with AMI. RESULTS Progranulin levels were obviously elevated in AMI patients compared to control subjects (P=0.0001). Correlation analysis showed that progranulin levels were positively associated with coronary artery disease severity (r=0.380, P=0.0001), glucose (r=0.195, P=0.015), and myeloperoxidase (r=0.198, P=0.014). In logistic regression analysis, serum progranulin (Exp(B)=1.104, 95% CI=1.043-1.168, P=0.001), myeloperoxidase (Exp(B)=1.006, 95% CI=1.003-1.008, P=0.0001), and uric acid (Exp(B)=1.020, 95% CI=1.009-1.032, P=0.0001) were independent risk factors in AMI patients. CONCLUSIONS Patients with AMI had significantly higher serum progranulin concentrations than control subjects. This study suggests that serum progranulin is an independent risk predictor in Chinese patients with AMI.

The expression of myeloperoxidase in thrombi is associated with reduced heme oxygenase-1 induction and worse left ventricular remodeling in patients with acute ST-elevation myocardial infarction

Background

Myeloperoxidase (MPO) secreted by neutrophils is the enzyme that kills bacteria and other pathogens. Acute myocardial infarction (AMI) is usually caused by thrombosis in response to vulnerable plaque rupture. Circulating MPO was found to be associated with increased mortality in AMI patients. However, the relationship between MPO in thrombi and the prognosis of AMI patients remains unknown.

Hypothesis

MPO expression in thrombi is associated with the prognosis of patients who underwent primary percutaneous coronary intervention (PCI) after AMI.

Methods

This study included 41 consecutive patients with acute ST‐elevation myocardial infarction, who successfully underwent primary PCI, during which we collected thrombi remaining in the culprit artery using aspiration catheters. These thrombus samples were fixed, and immunohistochemical staining against MPO and heme oxygenase‐1 (HO‐1) was conducted. Enrolled patients were divided into two groups based on the induction of thrombotic MPO, which was quantified using Image J software.

Methods

We observed that increased MPO was associated with lower left ventricular ejection fraction (LVEF) and worse LV remodeling in AMI patients. Instead, patients with decreased thrombotic MPO induction had a considerable improvement in LVEF 1 month after discharge (54.4 ± 2.0% vs. 61.1 ± 2.3%, p < 0.01). In the MPO group, a reduction in the thrombotic HO‐1 level contributed to the development of adverse LV remodeling. Logistic regression showed that MPO was a considerable risk factor for adverse LV remodeling (adjusted OR 3.70, p < 0.05).

Conclusion

MPO expression in thrombi is associated with reduced LVEF and deteriorated LV remodeling in AMI patients, which may be due to HO‐1 suppression in thrombi.

Myeloperoxidase: A versatile mediator of endothelial dysfunction and therapeutic target during cardiovascular disease

Myeloperoxidase (MPO) is a prominent mammalian heme peroxidase and a fundamental component of the innate immune response against microbial pathogens. In recent times, MPO has received considerable attention as a key oxidative enzyme capable of impairing the bioactivity of nitric oxide (NO) and promoting endothelial dysfunction; a clinically relevant event that manifests throughout the development of inflammatory cardiovascular disease. Increasing evidence indicates that during cardiovascular disease, MPO is released intravascularly by activated leukocytes resulting in its transport and sequestration within the vascular endothelium. At this site, MPO catalyzes various oxidative reactions that are capable of promoting vascular inflammation and impairing NO bioactivity and endothelial function. In particular, MPO catalyzes the production of the potent oxidant hypochlorous acid (HOCl) and the catalytic consumption of NO via the enzyme's NO oxidase activity. An emerging paradigm is the ability of MPO to also influence endothelial function via non-catalytic, cytokine-like activities. In this review article we discuss the implications of our increasing knowledge of the versatility of MPO's actions as a mediator of cardiovascular disease and endothelial dysfunction for the development of new pharmacological agents capable of effectively combating MPO's pathogenic activities. More specifically, we will (i) discuss the various transport mechanisms by which MPO accumulates into the endothelium of inflamed or diseased arteries, (ii) detail the clinical and basic scientific evidence identifying MPO as a significant cause of endothelial dysfunction and cardiovascular disease, (iii) provide an up-to-date coverage on the different oxidative mechanisms by which MPO can impair endothelial function during cardiovascular disease including an evaluation of the contributions of MPO-catalyzed HOCl production and NO oxidation, and (iv) outline the novel non-enzymatic mechanisms of MPO and their potential contribution to endothelial dysfunction. Finally, we deliver a detailed appraisal of the different pharmacological strategies available for targeting the catalytic and non-catalytic modes-of-action of MPO in order to protect against endothelial dysfunction in cardiovascular disease.

Myeloperoxidase - A bridge linking inflammation and oxidative stress with cardiovascular disease

Myeloperoxidase (MPO) is a member of the superfamily of heme peroxidases that is mainly expressed in neutrophils and monocytes. MPO-derived reactive species play a key role in neutrophil antimicrobial activity and human defense against various pathogens primarily by participating in phagocytosis. Elevated MPO levels in circulation are associated with inflammation and increased oxidative stress. Multiple lines of evidence suggest an association between MPO and cardiovascular disease (CVD) including coronary artery disease, congestive heart failure, arterial hypertension, pulmonary arterial hypertension, peripheral arterial disease, myocardial ischemia/reperfusion-related injury, stroke, cardiac arrhythmia and venous thrombosis. Elevated MPO levels are associated with a poor prognosis including increased risk for overall and CVD-related mortality. Elevated MPO may signify an increased risk for CVD for at least 2 reasons. First, low-grade inflammation and increased oxidative stress coexist with many metabolic abnormalities and comorbidities and consequently an elevated MPO level may represent an increased cardiometabolic risk in general. Second, MPO produces a large number of highly reactive species which can attack, destroy or modify the function of every known cellular component. The most common MPO actions relevant to CVD are generation of dysfunctional lipoproteins with an increased atherogenicity potential, reduced NO availability, endothelial dysfunction, impaired vasoreactivity and atherosclerotic plaque instability. These actions strongly suggest that MPO is directly involved in the pathophysiology of CVD. In this regard MPO may be seen as a mediator or an instrument through which inflammation promotes CVD at molecular and cellular level. Clinical value of MPO therapeutic inhibition remains to be tested.

The roles of myeloperoxidase in coronary artery disease and its potential implication in plaque rupture

Atherosclerosis is the main pathophysiological process underlying coronary artery disease (CAD). Acute complications of atherosclerosis, such as myocardial infarction, are caused by the rupture of vulnerable atherosclerotic plaques, which are characterized by thin, highly inflamed, and collagen-poor fibrous caps. Several lines of evidence mechanistically link the heme peroxidase myeloperoxidase (MPO), inflammation as well as acute and chronic manifestations of atherosclerosis. MPO and MPO-derived oxidants have been shown to contribute to the formation of foam cells, endothelial dysfunction and apoptosis, the activation of latent matrix metalloproteinases, and the expression of tissue factor that can promote the development of vulnerable plaque. As such, detection, quantification and imaging of MPO mass and activity have become useful in cardiac risk stratification, both for disease assessment and in the identification of patients at risk of plaque rupture. This review summarizes the current knowledge about the role of MPO in CAD with a focus on its possible roles in plaque rupture and recent advances to quantify and image MPO in plasma and atherosclerotic plaques.

System study of MPO promoter high-frequency polymorphic variants on transcription factor network

The neutrophil myeloperoxidase (MPO) promotes the oxidative stress by the production of active chlorinated molecules. The aim of this study was to investigate the association between MPO promoter polymorphic variants (rs2243827 and rs2333227) and, its serum level in patients with the stenosis of coronary arteries. Furthermore, a system approach was applied to create the MPO transcription factor network. A total of one hundred fifty six subjects (controls, stenosis<5%, n=71 and patients, stenosis>70%, n=85) undergoing coronary angiography were recruited. The polymorphic haplotypes and serum MPO level were identified using ARMS-PCR and ELISA techniques, respectively. The MPO transcription factor network was primarily created with PSICQUIC and ChIP data and, was improved with the predicted transcription factors. The regression analyses did not show an association between the serum MPO level and the extent of stenosis in coronary arteries. The network showed that the predicted transcription factors at the flanking regions of polymorphic variants are not directly interacted to MPO. In conclusion, the population and prediction studies showed no association between the serum MPO level, the promoter high-frequency polymorphic frequencies and the extent of stenosis in coronary arteries. A gene sub-cluster with MYB as central node was suggested to be involved with MPO on the transcription factor network.

Hypochlorous acid as a precursor of free radicals in living systems

Hypochlorous acid (HOCl) is produced in the human body by the family of mammalian heme peroxidases, mainly by myeloperoxidase, which is secreted by neutrophils and monocytes at sites of inflammation. This review discusses the reactions that occur between HOCl and the major classes of biologically important molecules (amino acids, proteins, nucleotides, nucleic acids, carbohydrates, lipids, and inorganic substances) to form free radicals. The generation of such free radical intermediates by HOCl and other reactive halogen species is accompanied by the development of halogenative stress, which causes a number of socially important diseases, such as cardiovascular, neurodegenerative, infectious, and other diseases usually associated with inflammatory response and characterized by the appearance of biomarkers of myeloperoxidase and halogenative stress. Investigations aimed at elucidating the mechanisms regulating the activity of enzyme systems that are responsible for the production of reactive halogen species are a crucial step in opening possibilities for control of the development of the body's inflammatory response.

Myeloperoxidase levels predicts angiographic severity of coronary artery disease in patients with chronic stable angina

BACKGROUND

Myeloperoxidase (MPO) has an important role in the both processes of inflammation and oxidative stress. It plays proatherogenic role via low-density lipoprotein oxidation, functional inactivation of the high-density lipoprotein and endothelial dysfunction, and seems to be involved in the atherogenesis of coronary arteries. This study designed to evaluate the association between the plasma MPO levels and angiographic severity of coronary artery disease (CAD) in patients with the stable CAD.

MATERIALS AND METHODS

Sixty-eight patients who had documented CAD with angiography and 66 subjects who had normal angiography were selected as case and the control groups for this study, respectively. Gensini scoring system was used for evaluation of severity of coronary artery stenosis. Plasma MPO and C-reactiveprotein (CRP) levels of both case and control groups were determined.

RESULTS

Plasma MPO levels and CRP levels were significantly higher in CAD patients (P < 0.001), and plasma levels of MPO and CRP were correlated with Genssini scores.

CONCLUSIONS

Our findings indicated that the plasma MPO levels increase in patients with stable CAD and hence that, it can be used as adiagnostic factor to predict the coronary artery atherosclerosis severity in stable CAD patients; However, it needs further widespread investigations to achieve an accurate cut point.

Accumulation of oxidative stress-related gene polymorphisms and the risk of coronary heart disease events in patients with type 2 diabetes--an 8-year prospective study

OBJECTIVE

Oxidative stress, which is provoked in patients with diabetes, plays critical roles in the pathogenesis of coronary heart disease (CHD). We simultaneously determined 5 relatively common genetic variants related to oxidative stress and evaluated the combined effect on CHD.

METHODS

We enrolled 1977 Japanese type 2 diabetic subjects without history of CVD (males 66.1%, 59.5 ± 10.0 years old), determined their genotypes regarding glutamate-cysteine ligase modifier subunit (GCLM) C-588T, manganese superoxide dismutase (SOD2) Val16Ala, endothelial nitric oxide synthase (NOS3) G894T, NAD(P)H oxidase p22phox (CYBA) C242T, and myeloperoxidase (MPO) G-463A polymorphisms, and prospectively evaluated the association between these polymorphisms and CHD events.

RESULTS

The median follow-up period was 7.5 years and there were 85 new CHD events. The single association analysis revealed that there were no statistically significant associations between each polymorphism and the prevalence of CHD. Interestingly, the risk of CHD event was higher with the increase of the total number of 10 concomitant unfavorable "pro-oxidant alleles" in each subject (p for trend = 0.018, log-rank test). Especially, the carriers of ≥8 pro-oxidant alleles had a significantly increased risk as compared to the carriers of <8 pro-oxidant alleles, whether the other clinical variables were adjusted (HR 2.92 with 95%CI 1.50-5.67, p = 0.002) or not (HR 2.89 with 95%CI 1.49-5.59, p = 0.002)..

CONCLUSIONS

Accumulation of gene polymorphisms related to oxidative stress is likely associated with the development of CHD in patients with type 2 diabetes, suggesting that the combined information about these variants is useful to assess the risk of CHD.

Association of myeloperoxidase with total and cardiovascular mortality in individuals undergoing coronary angiography--the LURIC study

Background

The phagocytic enzyme myeloperoxidase (MPO) acts as a front-line defender against microorganisms. However, increased MPO levels have been found to be associated with complex and calcified atherosclerotic lesions and incident cardiovascular disease. Therefore, this study aimed to investigate a predictive role of MPO, a biomarker of inflammation and oxidative stress, for total and cardiovascular mortality in patients referred to coronary angiography.

Methods and results

MPO plasma concentrations along with eight MPO polymorphisms were determined in 3036 participants of the Ludwigshafen Risk and Cardiovascular Health study (median follow-up 7.75 years). MPO concentrations were positively associated with age, diabetes, smoking, markers of systemic inflammation (interleukin-6, fibrinogen, C-reactive protein, serum amyloid A) and vascular damage (vascular cellular adhesion molecule-1 and intercellular adhesion molecule-1) but negatively associated with HDL-cholesterol and apolipoprotein A-I. After adjustment for cardiovascular risk factors MPO concentrations in the highest versus the lowest quartile were associated with a 1.34-fold risk (95% CI: 1.09–1.67) for total mortality. In the adjusted model the hazard ratio for cardiovascular mortality in the highest MPO quartile was 1.42 (95% CI: 1.07–1.88). Five MPO polymorphisms were positively associated with MPO concentrations but not with mortality. Using Mendelian randomization, we did not obtain evidence for a causal association of MPO with either total or cardiovascular mortality.

Conclusions

MPO concentrations but not genetic variants at the MPO locus are independently associated with risk for total and cardiovascular mortality in coronary artery disease patients.

Myeloperoxidase G463A polymorphism and lung cancer risk in Asians: a pooled analysis

Myeloperoxidase (MPO) is an endogenous oxidant enzyme and can generate reactive oxygen species. The MPO G463A polymorphism influences MPO transcription levels and has been proposed to be associated with risk of lung cancer. To assess the effect of MPO G463A polymorphism on lung cancer risk in Asians, a pooled analysis of published case-control studies was performed. PubMed, Embase, China Biomedical Literature, and Wanfang Medicine databases were searched for eligible studies. The strength of the association between MPO G463A polymorphism and lung cancer risk was measured by odds ratio (OR) with 95 % confidence interval (95% CI). Finally, eight studies with a total of 1,679 lung cancer cases and 1,876 non-cancer controls were included. Overall, MPO G463A polymorphism was associated with decreased risk of lung cancer risk in Asians under two genetic models (OR AA vs. GG = 0.58, 95% CI 0.36-0.96, P = 0.033; OR AA vs. GG+AG = 0.60, 95% CI 0.37-0.98, P = 0.040). There was no obvious risk of publication bias in this meta-analysis. In conclusion, the pooled analysis suggests that MPO G463A polymorphism is associated with decreased risk of lung cancer risk in Asians.

Genome-wide and gene-centric analyses of circulating myeloperoxidase levels in the charge and care consortia

Increased systemic levels of myeloperoxidase (MPO) are associated with the risk of coronary artery disease (CAD). To identify the genetic factors that are associated with circulating MPO levels, we carried out a genome-wide association study (GWAS) and a gene-centric analysis in subjects of European ancestry and African Americans (AAs). A locus on chromosome 1q31.1 containing the complement factor H (CFH) gene was strongly associated with serum MPO levels in 9305 subjects of European ancestry (lead SNP rs800292; P = 4.89 × 10(-41)) and in 1690 AA subjects (rs505102; P = 1.05 × 10(-8)). Gene-centric analyses in 8335 subjects of European ancestry additionally identified two rare MPO coding sequence variants that were associated with serum MPO levels (rs28730837, P = 5.21 × 10(-12); rs35897051, P = 3.32 × 10(-8)). A GWAS for plasma MPO levels in 9260 European ancestry subjects identified a chromosome 17q22 region near MPO that was significantly associated (lead SNP rs6503905; P = 2.94 × 10(-12)), but the CFH locus did not exhibit evidence of association with plasma MPO levels. Functional analyses revealed that rs800292 was associated with levels of complement proteins in serum. Variants at chromosome 17q22 also had pleiotropic cis effects on gene expression. In a case-control analysis of ∼80 000 subjects from CARDIoGRAM, none of the identified single-nucleotide polymorphisms (SNPs) were associated with CAD. These results suggest that distinct genetic factors regulate serum and plasma MPO levels, which may have relevance for various acute and chronic inflammatory disorders. The clinical implications for CAD and a better understanding of the functional basis for the association of CFH and MPO variants with circulating MPO levels require further study.

Effects of diabetes and ovariectomy on rat hippocampus (a biochemical and stereological study)

Oxidative stress is one of the main reasons of both menopause and diabetes. So, it plays crucial role in the pathogeneses of that condition and disease. Therefore, the objective of the present study was to investigate the effects of menopause and diabetes upon the hippocampus using a rat model. Adult female Sprague Dawley rats (n = 24) were allocated randomly as follows; control (C group) ovariectomized (O group), diabetic (D group) and ovariectomy plus diabetic groups (DO group) (n = 6; in each group), respectively. For evaluating the results, tissue biochemistry and stereological analysis were made. Biochemistry results (lipid peroxidase (LPO); catalase (CAT); superoxide dismutase (SOD); total glutatyon (GSH); and myeloperoxidase (MPO) values) in Group C-DO were determined as 12.27, 21.88, 23.08 and 29.90 nmol/gr tissue; 59.3, 70.06, 69.7 and 78.1 mmol/min/mg tissue; 174.2, 156.4, 159.7 and 154.6 mmol/min/mg tissue; 3.63, 3.61, 4.21 and 3.97 nmol/mg tissue; and 5.05, 5.68, 5.58 and 6.19 µmol/min/mg tissue, respectively. Moreover, both menopause and diabetes led to change of lipid profiles. There were significant differences between the control and other groups (Group C and D-DO) (p < 0.01) and among experimental groups (p < 0.01) in terms of neuron number. When the volumes of the hippocampus were compared, there were no significant differences between the all groups (P > 0.05). At this point, we suggested that diabetes could aggravate deleterious effects of ovariectomy.

Myeloperoxidase: New Roles for an Old Molecule

Myeloperoxidase (MPO) is a member of the heme peroxidase-cyclooxygenase superfamily. It is abundantly expressed in neutrophils and monocytes. During inflammation MPO is released from leukocytes and catalyzes the formation of several reactive species and tissue damage. In this article we present state of the art knowledge on the general properties, biosynthesis and processing and trafficking of MPO. The basic functions of MPO in inflammation and oxidative stress are discussed in detail. This article also summarizes the studies that investigated the relationship between MPO and cardiovascular disease. An overview of the assays for determination of MPO, the sample type and preanalytical procedures is given. Future studies are needed before this marker is introduced into routine clinical practice.

Lack of association between plasma myeloperoxidase levels and angiographic severity of coronary artery disease in patients with acute coronary syndrome

OBJECTIVE

To evaluate the association between plasma myeloperoxidase (MPO) levels and angiographic severity of coronary atherosclerotic lesions in patients with non-ST elevation acute coronary syndrome (ACS).

DESIGN AND METHODS

This cross-sectional study examined high-risk ACS patients who underwent coronary angiography within 72 h of the onset of symptoms by measuring their plasma MPO levels after sheath insertion. Gensini score was used to evaluate angiographic severity of coronary artery disease.

RESULTS

A total of 48 patients were included in the study. Median MPO levels and Gensini scores were 6.9 ng/mL (4.4-73.5 ng/mL) and 10 (0-87.5), respectively. Spearman's correlation coefficient did not show a significant association between MPO levels and Gensini scores (r (s) = 0.2; p = 0.177). There was no correlation between MPO and age, hypertension, diabetes, leukocyte count, troponin I, CK-MB ≥ 2 × ULN (upper limit of normal), TIMI risk score ≥ 4 and Gensini score in the multivariate analysis.

CONCLUSION

Our findings indicate that MPO expression is not associated with anatomical severity of coronary lesions in ACS.