Clinical and genetic association of serum ceruloplasmin with cardiovascular risk

Ribosomal proteins: the missing piece in the inflammation puzzle?

Ribosomal proteins (RPs) are constituents of macromolecular machinery, ribosome that translates genetic information into proteins. Besides ribosomal functions, RPs are now getting appreciated for their 'moonlighting'/extra-ribosomal functions modulating many cellular processes. Accumulating evidence suggests that a number of RPs are involved in inflammation. Though acute inflammation is a part of the innate immune response, uncontrolled inflammation is a driving factor for several chronic inflammatory diseases. An in-depth understanding of inflammation regulation has always been valued for the better management of associated diseases. Hence, this review first outlines the common livelihood of RPs and then provides a comprehensive account of five RPs that significantly contribute to the inflammation process. Finally, we discuss the possible therapeutic uses of RPs against chronic inflammatory diseases.

Contaminant Metals and Cardiovascular Health

A growing body of research has begun to link exposure to environmental contaminants, such as heavy metals, with a variety of negative health outcomes. In this paper, we sought to review the current research describing the impact of certain common contaminant metals on cardiovascular (CV) health. We reviewed ten metals: lead, barium, nickel, chromium, cadmium, arsenic, mercury, selenium, zinc, and copper. After a literature review, we briefly summarized the routes of environmental exposure, pathophysiological mechanisms, CV health impacts, and exposure prevention and/or mitigation strategies for each metal. The resulting article discloses a broad spectrum of pathological significance, from relatively benign substances with little to no described effects on CV health, such as chromium and selenium, to substances with a wide-ranging and relatively severe spectrum of CV pathologies, such as arsenic, cadmium, and lead. It is our hope that this article will provide clinicians with a practical overview of the impact of these common environmental contaminants on CV health as well as highlight areas that require further investigation to better understand how these metals impact the incidence and progression of CV diseases.

Dysregulation of metalloproteins in ischemic heart disease patients with systolic dysfunction

Ischemic heart disease (IHD) is the leading cause of mortality worldwide. Metalloproteins have been linked to human health and diseases. The molecular functions of metalloproteins in IHD is not well understood and require further exploration. The objective of this study was to find out the role of metalloproteins in the pericardial fluid of IHD patients having normal (EF > 45) and impaired (EF < 45) left ventricular ejection fraction (LVEF). IHD patients were grouped into two categories: LVEF<45 (n = 12) and LVEF >45 (n = 33). Pooled samples of pericardial fluid were fractionated by using ZOOM-isoelectric focusing (IEF) followed by further processing using one-dimensional gel electrophoresis (1D SDS-PAGE) and filter-aided sample preparation (FASP). Tryptic peptides of each fraction and differential bands were then analyzed by nano-LC-ESI-MS/MS. Protein identification was performed through a Mascot search engine using NCBI-Prot and SwissProt databases. A total of 1082 proteins including 154 metalloproteins were identified. In the differential bands, 60 metalloproteins were identified, while 115 metalloproteins were identified in all ZOOM-IEF fractions. Twelve differentially expressed metalloproteins were selected in the intense bands according to their molecular weight (MW) and isoelectric point (pI). The 12 differentially expressed metalloprotein includes ceruloplasmin, Prothrombin, Vitamin K-dependent protein, Fibulin-1, Ribosomal protein S6 kinase alpha-6, nidogen, partial, Serum albumin, Hemopexin, C-reactive protein, Serum amyloid P-component, and Intelectin-1 protein which were all up-regulated while serotransferrin is the only metalloprotein that was down-regulated in impaired (LVEF<45) group. Among the metalloproteins, Zn-binding proteins are 36.5 % followed by Ca-binging 32.2 %, and Fe-binging 12.2 %. KEGG, pathway analysis revealed the association of ceruloplasmin and serotransferrin with the ferroptosis pathway. In conclusion, 154 metalloproteins were identified of them the Zn-binding protein followed by Ca-binding and Fe-binding proteins were the most abundant metalloproteins. The two metalloproteins, the Cu-binding protein ceruloplasmin, and Fe-binding protein serotransferrin are involved in the ferroptosis pathway, an iron-dependent form of regulated cell death that has been linked to cardiac pathology, especially in IHD patients having impaired systolic (LVEF<45) dysfunction. However, further research is required to validate these findings.

The Search for Associations of Serum Proteins with the Presence of Unstable Atherosclerotic Plaque in Coronary Atherosclerosis

To study the associations of blood proteins with the presence of unstable atherosclerotic plaques in the arteries of patients with coronary atherosclerosis using quantitative proteomics. The studies involved two groups of men with coronary atherosclerosis (group 1 (St) had only stable atherosclerotic plaques; group 2 (Ns) had only unstable atherosclerotic plaques, according to histological analysis of tissue samples); the average age of patients was 57.95 ± 7.22. Protein concentrations in serum samples were determined using the PeptiQuant Plus Proteomics Kit. The identification of protein fractions was carried out by monitoring multiple reactions on a Q-TRAP 6500 mass spectrometer combined with a liquid chromatograph. Mass spectrometric identification revealed in serum samples from patients with unstable atherosclerotic plaques a reduced concentration of proteins in the blood: α-1-acid glycoprotein, α-1-antichymotrypsin, α-1-antitrypsin, ceruloplasmin, hemopexin, haptoglobin, apolipoprotein B-100, apolipoprotein L1, afamin and complement component (C3, C7, C9). Moreover, at the same time a high concentration complements factor H and attractin. The differences were considered significant at p < 0.05. It was found that the instability of atherosclerotic plaques is associated with the concentration of proteins: afamin, attractin, components of the complement system, hemopexin and haptoglobin. The data of our study showed the association of some blood proteins with the instability of atherosclerotic plaques in coronary atherosclerosis. Their potential role in the development of this disease and the possibility of using the studied proteins as biomarkers requires further research.

Comparative Use of Contralateral and Sham-Operated Controls Reveals Traces of a Bilateral Genetic Response in the Rat Brain after Focal Stroke

Ischemic stroke is a multifactorial disease with a complex etiology and global consequences. Model animals are widely used in stroke studies. Various controls, either brain samples from sham-operated (SO) animals or symmetrically located brain samples from the opposite (contralateral) hemisphere (CH), are often used to analyze the processes in the damaged (ipsilateral) hemisphere (IH) after focal stroke. However, previously, it was shown that focal ischemia can lead to metabolic and transcriptomic changes not only in the IH but also in the CH. Here, using a transient middle cerebral artery occlusion (tMCAO) model and genome-wide RNA sequencing, we identified 1941 overlapping differentially expressed genes (DEGs) with a cutoff value >1.5 and Padj < 0.05 that reflected the general transcriptome response of IH subcortical cells at 24 h after tMCAO using both SO and CH controls. Concomitantly, 861 genes were differentially expressed in IH vs. SO, whereas they were not vs. the CH control. Furthermore, they were associated with apoptosis, the cell cycle, and neurotransmitter responses. In turn, we identified 221 DEGs in IH vs. CH, which were non-DEGs vs. the SO control. Moreover, they were predominantly associated with immune-related response. We believe that both sets of non-overlapping genes recorded transcriptome changes in IH cells associated with transhemispheric differences after focal cerebral ischemia. Thus, the specific response of the CH transcriptome should be considered when using it as a control in studies of target brain regions in diseases that induce a global bilateral genetic response, such as stroke.

An Emerging Role of Defective Copper Metabolism in Heart Disease

Copper is an essential trace metal element that significantly affects human physiology and pathology by regulating various important biological processes, including mitochondrial oxidative phosphorylation, iron mobilization, connective tissue crosslinking, antioxidant defense, melanin synthesis, blood clotting, and neuron peptide maturation. Increasing lines of evidence obtained from studies of cell culture, animals, and human genetics have demonstrated that dysregulation of copper metabolism causes heart disease, which is the leading cause of mortality in the US. Defects of copper homeostasis caused by perturbed regulation of copper chaperones or copper transporters or by copper deficiency resulted in various types of heart disease, including cardiac hypertrophy, heart failure, ischemic heart disease, and diabetes mellitus cardiomyopathy. This review aims to provide a timely summary of the effects of defective copper homeostasis on heart disease and discuss potential underlying molecular mechanisms.

Molecular Functions of Ceruloplasmin in Metabolic Disease Pathology

Ceruloplasmin (CP) is a multicopper oxidase and antioxidant that is mainly produced in the liver. CP not only plays a crucial role in the metabolic balance of copper and iron through its oxidase function but also exhibits antioxidant activity. In addition, CP is an acute-phase protein. In addition to being associated with aceruloplasminemia and neurodegenerative diseases such as Wilson's disease, Alzheimer's disease, and Parkinson's disease, CP also plays an important role in metabolic diseases, which are caused by metabolic disorders and vigorous metabolism, mainly including diabetes, obesity, hyperlipidemia, etc. Based on the physiological functions of CP, we provide an overview of the association of type 2 diabetes, obesity, hyperlipidemia, coronary heart disease, CP oxidative stress, inflammation, and metabolism of copper and iron. Studies have shown that metabolic diseases are closely related to systemic inflammation, oxidative stress, and disorders of copper and iron metabolism. Therefore, we conclude that CP, which can reduce the formation of free radicals in tissues, can be induced during inflammation and infection, and can correct the metabolic disorder of copper and iron, has protective and diagnostic effects on metabolic diseases.

Ceruloplasmin as Redox Marker Related to Heart Failure Severity

This study examined ceruloplasmin levels in patients with HFrEF, depending on cardiopulmonary exercise testing (CPET) parameters; a correlation was found between ceruloplasmin (CER) and iron and hepatic status, inflammatory and redox biomarkers. A group of 552 patients was divided according to Weber’s classification: there were 72 (13%) patients in class A (peak VO₂ > 20 mL/kg/min), 116 (21%) patients in class B (peak VO₂ 16–20 mL/kg/min), 276 (50%) patients in class C (peak VO₂ 10–15.9 mL/kg/min) and 88 (16%) patients in class D (peak VO₂ < 10 mL/kg/min). A higher concentration of CER was found in patients with peak VO₂ < 16 mL/kg/min and VE/CO₂ slope > 45 compared to patients with VE/CO₂ slope < 45 (escectively CER 30.6 mg/dL and 27.5 mg/dL). A significantly positive correlation was found between ceruloplasmin and NYHA class, RV diameter, NT-proBNP, uric acid, total protein, fibrinogen and hepatic enzymes. CER was positively correlated with both total oxidant status (TOS), total antioxidant capacity (TAC) and malondialdehyde. A model constructed to predict CER concentration indicated that TOS, malondialdehyde and alkaline phosphatase were independent predictive variables (R² 0.14, p < 0.001). CER as a continuous variable was an independent predictor of pVO₂ ≤ 12 mL/kg/min after adjustment for sex, age and BMI. These results provide the basis of a new classification to encourage the determination of CER as a useful biomarker in HFrEF.

The role of high-density lipoprotein cholesterol, apolipoprotein A and paraoxonase-1 in the pathophysiology of neuroprogressive disorders

Lowered high-density lipoprotein (HDL) cholesterol has been reported in major depressive disorder, bipolar disorder, first episode of psychosis, and schizophrenia. HDL, its major apolipoprotein component, ApoA1, and the antioxidant enzyme paraoxonase (PON)1 (which is normally bound to ApoA1) all have anti-atherogenic, antioxidant, anti-inflammatory, and immunomodulatory roles, which are discussed in this paper. The paper details the pathways mediating the anti-inflammatory effects of HDL, ApoA1 and PON1 and describes the mechanisms leading to compromised HDL and PON1 levels and function in an environment of chronic inflammation. The molecular mechanisms by which changes in HDL, ApoA1 and PON1 might contribute to the pathophysiology of the neuroprogressive disorders are explained. Moreover, the anti-inflammatory actions of ApoM-mediated sphingosine 1-phosphate (S1P) signalling are reviewed as well as the deleterious effects of chronic inflammation and oxidative stress on ApoM/S1P signalling. Finally, therapeutic interventions specifically aimed at improving the levels and function of HDL and PON1 while reducing levels of inflammation and oxidative stress are considered. These include the so-called Mediterranean diet, extra virgin olive oil, polyphenols, flavonoids, isoflavones, pomegranate juice, melatonin and the Mediterranean diet combined with the ketogenic diet.

Ceruloplasmin and Coronary Heart Disease-A Systematic Review

Several studies indicate that oxidative stress might play a central role in the initiation and maintenance of cardiovascular diseases. It remains unclear whether ceruloplasmin acts as a passive marker of inflammation or as a causal mediator. To better understand the impact of ceruloplasmin blood levels on the risk of cardiovascular disease, and paying special attention to coronary heart disease, we conducted a search on the two most commonly used electronic databases (Medline via PubMed and EMBASE) to analyze current assessment using observational studies in the general adult population. Each study was quality rated using criteria developed by the US Preventive Services Task Force. Most of 18 eligible studies reviewed support a direct relationship between ceruloplasmin elevated levels and incidence of coronary heart disease. Our results highlight the importance of promoting clinical trials that determine the functions of ceruloplasmin as a mediator in the development of coronary heart disease and evaluate whether the treatment of elevated ceruloplasmin levels has a role in the prognosis or prevention of this condition.

Selenium and Copper as Biomarkers for Pulmonary Arterial Hypertension in Systemic Sclerosis

Circulating selenoprotein P (SELENOP) constitutes an established biomarker of Se status. SELENOP concentrations are reduced in inflammation and severe disease. Recently, elevated SELENOP levels have been suggested as diagnostic marker and therapeutic target in pulmonary arterial hypertension (PAH). We decided to re-evaluate this hypothesis. A group of healthy controls (n = 30) was compared with patients suffering from systemic sclerosis (SSc, n = 66), one third with SSc-related PAH. Serum was analysed for trace elements and protein biomarkers, namely SELENOP, glutathione peroxidase 3 (GPx3) and ceruloplasmin (CP). Compared to controls, patients with SSc-related PAH displayed reduced serum Se (91 ± 2 vs. 68 ± 2 µg/L) and SELENOP concentrations (3.7 ± 0.8 vs. 2.7 ± 0.9 mg/L), along with lower GPx3 activity (278 ± 40 vs. 231 ± 54 U/L). All three biomarkers of Se status were particularly low in patients with skin involvement. Serum Cu was not different between the groups, but patients with SSc-related PAH showed elevated ratios of Cu/Se and CP/SELENOP as compared to controls. Our data indicate that patients with SSc-related PAH are characterized by reduced Se status in combination with elevated CP, in line with other inflammatory diseases. Further analyses are needed to verify the diagnostic value of these TE-related biomarkers in PAH.

From genome-wide association studies to Mendelian randomization: novel opportunities for understanding cardiovascular disease causality, pathogenesis, prevention, and treatment

The Mendelian randomization approach is an epidemiological study design incorporating genetic information into traditional epidemiological studies to infer causality of biomarkers, risk factors, or lifestyle factors on disease risk. Mendelian randomization studies often draw on novel information generated in genome-wide association studies on causal associations between genetic variants and a risk factor or lifestyle factor. Such information can then be used in a largely unconfounded study design free of reverse causation to understand if and how risk factors and lifestyle factors cause cardiovascular disease. If causation is demonstrated, an opportunity for prevention of disease is identified; importantly however, before prevention or treatment can be implemented, randomized intervention trials altering risk factor levels or improving deleterious lifestyle factors needs to document reductions in cardiovascular disease in a safe and side-effect sparse manner. Documentation of causality can also inform on potential drug targets, more likely to be successful than prior approaches often relying on animal or cell studies mainly. The present review summarizes the history and background of Mendelian randomization, the study design, assumptions for using the design, and the most common caveats, followed by a discussion on advantages and disadvantages of different types of Mendelian randomization studies using one or more samples and different levels of information on study participants. The review also provides an overview of results on many of the risk factors and lifestyle factors for cardiovascular disease examined to date using the Mendelian randomization study design.

Oxidative Stress Related to Iron Metabolism in Relapsing Remitting Multiple Sclerosis Patients With Low Disability

Oxidative status may play a role in chronic inflammation and neurodegeneration which are considered critical etiopathogenetic factors in Multiple Sclerosis (MS), both in the early phase of the disease and in the progressive one. The aim of this study is to explore oxidative status related to iron metabolism in peripheral blood of stable Relapsing-Remitting MS with low disability. We studied 60 Relapsing-Remitting MS patients (age 37.2 ± 9.06, EDSS median 1.0), and 40 healthy controls (age 40.3 ± 10.86). We measured total hydroperoxides (dROMs test) and Total Antioxidant Status (TAS), along with the iron metabolism biomarkers: Iron (Fe), ferritin (Ferr), transferrin (Tf), transferrin saturation (Tfsat), and ceruloplasmin (Cp) panel biomarkers [concentration (iCp) and enzymatic activity (eCp), copper (Cu), ceruloplasmin specific activity (eCp:iCp), copper to ceruloplasmin ratio (Cu:Cp), non-ceruloplasmin copper (nCp-Cu)]. We computed also the Cp:Tf ratio as an index of oxidative stress related to iron metabolism. We found lower TAS levels in MS patients than in healthy controls (CTRL) and normal reference level and higher dROMs and Cp:Tf ratio in MS than in healthy controls. Cp and Cu were higher in MS while biomarkers of iron metabolism were not different between patients and controls. Both in controls and MS, dROMs correlated with iCp (CTRL r = 0.821, p < 0.001; MS r = 0.775 p < 0.001) and eCp (CTRL r = 0.734, p < 0.001; MS r = 0.820 p < 0.001). Moreover, only in MS group iCp correlated negatively with Tfsat (r = -0.257, p = 0.047). Dividing MS patients in “untreated” group and “treated” group, we found a significant difference in Fe values [F(2, 97) = 10.136, p < 0.001]; in particular “MS untreated” showed higher mean values (mean = 114.5, SD = 39.37 μg/dL) than CTRL (mean 78.6, SD = 27.55 μg/dL p = 0.001) and “MS treated” (mean = 72.4, SD = 38.08 μg/dL; p < 0.001). Moreover, “MS untreated” showed significantly higher values of Cp:Tf (mean = 10.19, SD = 1.77^∗10^-2; p = 0.015), than CTRL (mean = 9.03, SD = 1.46 ^∗10^-2). These results suggest that chronic oxidative stress is relevant also in the remitting phase of the disease in patients with low disability and short disease duration. Therefore, treatment with antioxidants may be beneficial also in the early stage of the disease to preserve neuronal reserve.

Activity of Antioxidant Enzymes and Their Association with Lipid Profile in Mexican People without Cardiovascular Disease: An Analysis of Interactions

Dyslipidemia and oxidative stress are both considered to be factors involved in cardiovascular disease; however, the relationship between them has been little explored. In this work, we studied the association between the lipid profile and the activity of antioxidant enzymes such as paraoxonase-1 (PON1), superoxide dismutase 1 (SOD1), ceruloplasmin, and catalase, as well as total antioxidant capacity (the ferric-reducing ability of plasma (FRAP)), in 626 volunteers without cardiovascular disease. Their lipid profile was evaluated, and they were classified as having or not having high triglycerides (↑TG), high low-density cholesterol (↑LDLC), and low high-density cholesterol (↓HDLC), resulting in eight groups: Without dyslipidemia, ↑TG, ↑LDLC, ↓HDLC, ↑TG↑LDLC, ↑TG↓HDLC, ↑LDLC↓HDLC, and ↑TG↑LDLC↓HDLC. When comparisons by group were made, no significant differences in the activity of antioxidant enzymes were obtained. However, the linear regression analysis considering the potential interactions between ↑TG, ↑LDLC, and ↓HDLC suggested a triple interaction between the three lipid profile alterations on the activity of PON1 and a double interaction between ↑TG and ↑LDLC on ferroxidase-ceruloplasmin activity. The analysis presented in this work showed an association between the lipid profile and antioxidant-enzyme activity and highlighted the importance of considering the interactions between the components of a phenomenon instead of studying them individually. Longitudinal studies are needed to elucidate the nature of these associations.

Acidic pH promotes oxidation-induced dissociation of C-reactive protein

BACKGROUND

Circulating levels of the systemic inflammation marker C-reactive protein (CRP) have been associated with increased risk and poor outcomes of many diseases, such as cardiovascular events and cancer. Accumulating evidence has indicated that the conformational rearrangement of human pentameric CRP (pCRP) to monomeric CRP (mCRP) is a prerequisite for participation in the pathogenesis. Therefore, determining the mechanism of the dissociation of pCRP into pro-inflammatory mCRP under physiological/pathological circumstances has been intriguing.

METHODS

The effects of oxidative and acidic stress occurring in inflammation on pCRP were examined by electrophoresis, electron microscopy, protein fluorescence, neoepitope expression and endothelial cell responses.

RESULTS

Reactive oxygen species (ROS) generated by the copper-hydrogen peroxide system could rapidly induce the dissociation of CRP at mild acidic pH within four hours, but not at physiological pH of 7.4. Meanwhile, mannitol, a ROS scavenger, could not protect against dissociation, which implied that local ROS from accessible histidine residues may be crucially beneficial to the formation of mCRP in a redox-balanced microenvironment. Furthermore, mCRP generated by ROS could be reduced by DTT, which indicated the exposure of functional motif aa35-47, and showed potent proinflammatory actions on endothelial cells, comparable to mCRP generated by urea.

CONCLUSION

dissociation of pCRP to mCRP could be rapidly induced by ROS from copper- hydrogen peroxide system in dependence on mildly acidic stress regardless of a redox-balanced microenvironment.

TRAIL and Ceruloplasmin Inverse Correlation as a Representative Crosstalk between Inflammation and Oxidative Stress

Objective

“Oxinflammation” is a recently coined term that defines the deleterious crosstalk between inflammatory and redox systemic processes, which underlie several diseases. Oxinflammation could be latently responsible for the predisposition of certain healthy individuals to disease development. The oxinflammatory pathway has been recently suggested to play a crucial role in regulating the activity of TNF-related apoptosis-inducing ligand (TRAIL), a TNF superfamily member that can mediate multiple signals in physiological and pathological processes. Therefore, we investigated the associations between TRAIL and key players of vascular redox homeostasis.

Methods

We measured circulating TRAIL levels relative to praoxonas-1, lipoprotein phospholipase-A2, and ceruloplasmin levels in a cohort of healthy subjects (n = 209).

Results

Multivariate analysis revealed that ceruloplasmin levels were significantly inversely associated with TRAIL levels (r = −0.431, p < 0.001). The observed association retained statistical significance after adjustment for additional confounding factors. After stratification for high-sensitivity C-reactive protein levels, the inverse association between TRAIL and ceruloplasmin levels remained strong and significant (r = −0.508, p < 0.001, R² = 0.260) only in the presence of inflammation, confirming the role of inflammation as emerged in in vitro experiments where recombinant TRAIL decreased ceruloplasmin expression levels in TNF-treated PBMC cultures.

Conclusion

The results indicated that in an inflammatory milieu, TRAIL downregulates ceruloplasmin expression, highlighting a signaling axis involving TRAIL and ceruloplasmin that are linked via inflammation and providing important insights with potential clinical implications.

Peroxidasin contributes to lung host defense by direct binding and killing of gram-negative bacteria

Innate immune recognition is classically mediated by the interaction of host pattern-recognition receptors and pathogen-associated molecular patterns; this triggers a series of downstream signaling events that facilitate killing and elimination of invading pathogens. In this report, we provide the first evidence that peroxidasin (PXDN; also known as vascular peroxidase-1) directly binds to gram-negative bacteria and mediates bactericidal activity, thus, contributing to lung host defense. PXDN contains five leucine-rich repeats and four immunoglobulin domains, which allows for its interaction with lipopolysaccharide, a membrane component of gram-negative bacteria. Bactericidal activity of PXDN is mediated via its capacity to generate hypohalous acids. Deficiency of PXDN results in a failure to eradicate Pseudomonas aeruginosa and increased mortality in a murine model of Pseudomonas lung infection. These observations indicate that PXDN mediates previously unrecognized host defense functions against gram-negative bacterial pathogens.

Oxidative stress markers and antioxidant activity in patients admitted to Intensive Care Unit with acute myocardial infarction

OBJECTIVES

The aim of the study was to compare the levels of oxidative stress biomarkers and antioxidants in acute myocardial infarction (AMI) patients with healthy individuals and to investigate the effectiveness of these parameters as risk or illness indicators.

METHODOLOGY

This study was conducted on AMI patients admitted to Intensive Care Unit of Al-Salam Hospital and Ibn-Sina Hospital in Mosul, Iraq. Considering inclusion and exclusion criteria, a total of 161 patients and 156 healthy individuals in the age group of 30-80 years were selected for the study. The study groups were screened by estimating cardiac markers and electrocardiography (ECG).

RESULTS

The results indicated a significant increase in the level of serum malondialdehyde, peroxynitrite, and uric acid (P< 0.001). A minor increase in the serum ceruloplasmin level was observed in patients with AMI as compared to healthy individuals. The study also observed a significant decrease in the level of glutathione, Vitamin E, and Vitamin C (P< 0.001), with no significant difference in the level of Vitamin A in patients with AMI.

CONCLUSION

The imbalance in the oxidative status and antioxidant activity in AMI patients reflects the importance of measuring the level of serum oxidative stress biomarkers and antioxidants as a diagnostic and prognostic tool for the medical management of AMI. Oxidative stress biomarkers and antioxidants might be good predictors or indicators for the risk of AMI. Oxidative stress markers contribute in the pathogenesis of AMI and excess of reactive oxygen species overwhelm the stability of the antioxidants.

Serum quantitative proteomic analysis of patients with keshan disease based on iTRAQ labeling technique: A first term study

Keshan disease (KD), an endemic myocardiopathy, with unknown etiology, is still threatening human health. Proteomics studies of Keshan disease is rarely known. In the current study, isobaric tags for relative and absolute quantitation (iTRAQ) labeling coupled with two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) was firstly used to screen for the differentially expressed proteins (DEPs) in serum between Keshan disease and healthy residents in endemic area. 27 differentially expressed proteins were quantified, 9 of which were significantly altered (fold change > 1.2 or < 0.8) between the two groups. Bioinformatic analysis revealed that a wide variety of biology process played roles in KD pathophysiology. These differentially expressed proteins were mainly involved in complement coagulation pathways. A significant high serum level of LGALS3BP were observed. Our first term study in KD proteomics provided new view into the molecular mechanisms of KD disease.

The GAIT translational control system

The interferon (IFN)‐γ‐activated inhibitor of translation (GAIT) system directs transcript‐selective translational control of functionally related genes. In myeloid cells, IFN‐γ induces formation of a multiprotein GAIT complex that binds structural GAIT elements in the 3′‐untranslated regions (UTRs) of multiple inflammation‐related mRNAs, including ceruloplasmin and VEGF‐A, and represses their translation. The human GAIT complex is a heterotetramer containing glutamyl‐prolyl tRNA synthetase (EPRS), NS1‐associated protein 1 (NSAP1), ribosomal protein L13a (L13a), and glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH). A network of IFN‐γ‐stimulated kinases regulates recruitment and assembly of GAIT complex constituents. Activation of cyclin‐dependent kinase 5 (Cdk5), mammalian target of rapamycin complex 1 (mTORC1), and S6K1 kinases induces EPRS release from its parental multiaminoacyl tRNA synthetase complex to join NSAP1 in a ‘pre‐GAIT’ complex. Subsequently, the DAPK‐ZIPK kinase axis phosphorylates L13a, inducing release from the 60S ribosomal subunit and binding to GAPDH. The subcomplexes join to form the functional GAIT complex. Each constituent has a distinct role in the GAIT system. EPRS binds the GAIT element in target mRNAs, NSAP1 negatively regulates mRNA binding, L13a binds eIF4G to block ribosome recruitment, and GAPDH shields L13a from proteasomal degradation. The GAIT system is susceptible to genetic and condition‐specific regulation. An N‐terminus EPRS truncate is a dominant‐negative inhibitor ensuring a ‘translational trickle’ of target transcripts. Also, hypoxia and oxidatively modified lipoproteins regulate GAIT activity. Mouse models exhibiting absent or genetically modified GAIT complex constituents are beginning to elucidate the physiological role of the GAIT system, particularly in the resolution of chronic inflammation. Finally, GAIT‐like systems in proto‐chordates suggests an evolutionarily conserved role of the pathway in innate immunity. WIREs RNA 2018, 9:e1441. doi: 10.1002/wrna.1441

This article is categorized under: 1

Translation > Translation Regulation

2

RNA Interactions with Proteins and Other Molecules > RNA–Protein Complexes

3

Regulatory RNAs/RNAi/Riboswitches > Riboswitches

The Genetic Architecture of Coronary Artery Disease: Current Knowledge and Future Opportunities

PURPOSE OF REVIEW

We provide an overview of our current understanding of the genetic architecture of coronary artery disease (CAD) and discuss areas of research that provide excellent opportunities for further exploration.

RECENT FINDINGS

Large-scale studies in human populations, coupled with rapid advances in genetic technologies over the last decade, have clearly established the association of common genetic variation with risk of CAD. However, the effect sizes of the susceptibility alleles are for the most part modest and collectively explain only a small fraction of the overall heritability. By comparison, evidence that rare variants make a substantial contribution to risk of CAD has been somewhat disappointing thus far, suggesting that other biological mechanisms have yet to be discovered. Emerging data suggests that novel pathways involved in the development of CAD can be identified through complementary and integrative systems genetics strategies in mice or humans. There is also convincing evidence that gut bacteria play a previously unrecognized role in the development of CAD, particularly through metabolism of certain dietary nutrients that lead to proatherogenic metabolites in the circulation. A major effort is now underway to functionally understand the newly discovered genetic and biological associations for CAD, which could lead to the development of potentially novel therapeutic strategies. Other important areas of investigation for understanding the pathophysiology of CAD, including epistatic interactions between genes or with either sex and environmental factors, have not been studied on a broad scope and represent additional opportunities for future studies.

Heme-nitrosylated hemoglobin and oxidative stress in women consuming combined contraceptives. Clinical application of the EPR spectroscopy

An increased risk of venous thromboembolism was identified in young women consuming combined contraceptive pills (CP) suggesting a disturbance of vascular homeostasis but the impact of CP on endothelial function and redox status of the vasculature was not thoroughly analyzed. We measured the bioavailability of nitric oxide (NO), a main mediator of vascular homeostasis in a cohort of young female subjects (n=114) and compared the results in users or not of CPs containing ethinyl estradiol and synthetic progestogens. Vascular NO availability was measured by quantification of the heme-nitrosylated hemoglobin (5-coordinate-α-HbNO) concentrations in venous erythrocytes using Electron Paramagnetic Resonance spectroscopy (EPR). Vascular oxidative status was assessed by measurement of peroxides in plasma, and of the thiol redox state in erythrocytes. In addition, endothelial function was assessed by digital reactive hyperemia pulse tonometry using EndoPAT. We observed that the HbNO level was significantly lower in erythrocytes of subjects consuming CPs versus controls (162±8 and 217±12 nmol/L). This correlated with significantly increased levels of plasma peroxides (1.8±0.1mmol/L versus 0.8±0.1mmol/L in controls) and decreased concentrations of erythrocyte reduced thiols (by 12%). Interestingly, the level of oxidized ceruloplasmin-Cu(II) was also significantly higher in the group consuming CPs. The EndoPAT index showed a trend towards impairment in CP users, and was significantly lower in subjects that consumed CPs containing drospirenone, and had lowest erythrocyte HbNO levels.

CONCLUSION

This cross-sectional cohort study demonstrates that a decrease of HbNO measured by quantitative EPR in human venous erythrocytes is correlated with the development of endothelial dysfunction under CPs consumption, in parallel with increased vascular oxidative stress.

Circulating ceruloplasmin, ceruloplasmin-associated genes, and the incidence of atrial fibrillation in the atherosclerosis risk in communities study

BACKGROUND

Ceruloplasmin (CP) may promote structural changes in the atrium making it more arrhythmogenic. We assessed the associations between CP, CP-associated genetic variants, and incident atrial fibrillation (AF) in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS AND RESULTS

We studied 10,059 men and women without prevalent AF aged 53 to 75years in 1996-1998 and followed through 2012. Circulating CP was measured in stored blood samples obtained in 1996-1998. Polymorphisms rs11708215 and rs13072552, previously associated with CP concentrations, were measured in 10,059 and 8829 participants respectively. AF was ascertained from study electrocardiograms, hospital discharge codes, and death certificates. Multivariable Cox models were run to study the association between circulating CP, CP-associated polymorphisms, and the incidence of AF. Over 10.5years of mean follow-up, 1357 cases of AF were identified. After adjusting for traditional risk factors and biomarkers, higher levels of circulating CP were associated with incident AF (hazard ratio [HR] 1.33, 95% confidence interval [CI] 1.11, 1.61 comparing top to bottom quartiles). Both rs11708215 and rs13072552 were significantly associated with CP levels. Presence of the CP-increasing alleles in rs11708215 and rs13072552, however, were significantly associated with lower risk of AF in whites (HR 0.84, 95%CI 0.76, 0.94, p=0.002 and HR 0.83; 95%CI 0.69, 0.99, p=0.043 respectively per CP-increasing allele in the final adjusted model) but not in African Americans.

CONCLUSIONS

Even though higher CP concentrations were associated with increased AF risk, genetic variants associated with higher CP decreased the risk of AF in whites. Our results suggest that circulating CP levels may not be causally related to risk of incident AF.

Ambient Air Pollution Is Associated With the Severity of Coronary Atherosclerosis and Incident Myocardial Infarction in Patients Undergoing Elective Cardiac Evaluation

Background

The effect of air pollution exposure on atherosclerosis severity or incident clinical events in patients with coronary artery disease is not known.

Methods and Results

We conducted a prospective longitudinal cohort study of 6575 Ohio residents undergoing elective diagnostic coronary angiography. Multinomial regression and Cox proportional hazards models were used to assess the relationship between exposure to fine particulate matter <2.5 μm in diameter (PM_2.5) and nitrogen dioxide on coronary artery disease severity at baseline and risk of myocardial infarction, stroke, or all‐cause mortality over 3 years of follow‐up. Among participants with coronary artery disease, exposure to PM_2.5 levels was associated with increased likelihood of having coronary atherosclerosis that was mild (odds ratio 1.43, 95% CI 1.11–1.83, P=0.005) and severe (odds ratio 1.63, 95% CI 1.26–2.11, P<0.0001), with the effect on severe coronary artery disease being significantly increased compared with mild disease (P_trend=0.03). Exposure to higher PM_2.5 levels was also significantly associated with increased risk of incident myocardial infarction (hazard ratio 1.33, 95% CI 1.02–1.73, P=0.03) but not stroke or all‐cause mortality. The association of PM_2.5 with incident myocardial infarction was not affected after adjustment for Framingham Adult Treatment Panel III (ATP III) risk score or statin therapy. In comparison, there were no significant associations between nitrogen dioxide levels and all‐cause mortality or risk of stroke after adjustment for Framingham ATP III risk score.

Conclusions

Exposure to PM_2.5 increased the likelihood of having severe coronary artery disease and the risk of incident myocardial infarction among patients undergoing elective cardiac evaluation. These results suggest that ambient air pollution exposure may be a modifiable risk factor for risk of myocardial infarction in a highly susceptible patient population.

[Myeloperoxidase activity in blood plasma as a criterion of therapy for patients with cardiovascular disease]

A significant increase in the myeloperoxidase (MPO) activity has been found in plasma of patients with stable angina and with acute coronary syndrome (ACS) in comparison with the control group. MPO concentration was significantly increased in plasma of ACS patients. Reduced MPO activity in the treated ACS patients correlated with a favorable outcome of the disease. Generally, changes in plasma MPO concentration coincided with changes in lactoferrin concentration thus confirming the role of neutrophil degranulation in the increase of plasma concentrations of these proteins. The increase in MPO activity was obviously determined by modification of the MPO protein caused by reactive oxygen species and halogen in the molar ratio of 1 : 25 and 1 : 50. The decrease in plasma MPO activity may be associated with increased plasma concentrations of the physiological inhibitor of its activity, ceruloplasmin, and also with modification of the MPO protein with reactive oxygen species and halogen at their molar ratio of 1 : 100 and higher. Thus, MPO activity may be used for evaluation of effectiveness of the treatment of cardiovascular diseases.

Genome-wide association study and targeted metabolomics identifies sex-specific association of CPS1 with coronary artery disease

Metabolites derived from dietary choline and L-carnitine, such as trimethylamine N-oxide and betaine, have recently been identified as novel risk factors for atherosclerosis in mice and humans. We sought to identify genetic factors associated with plasma betaine levels and determine their effect on risk of coronary artery disease (CAD). A two-stage genome-wide association study (GWAS) identified two significantly associated loci on chromosomes 2q34 and 5q14.1. The lead variant on 2q24 (rs715) localizes to carbamoyl-phosphate synthase 1 (CPS1), which encodes a mitochondrial enzyme that catalyses the first committed reaction and rate-limiting step in the urea cycle. Rs715 is also significantly associated with decreased levels of urea cycle metabolites and increased plasma glycine levels. Notably, rs715 yield a strikingly significant and protective association with decreased risk of CAD in only women. These results suggest that glycine metabolism and/or the urea cycle represent potentially novel sex-specific mechanisms for the development of atherosclerosis.

Dietary choline metabolites, such as trimethylamine N-oxide and betaine, have been associated with coronary artery disease (CAD). Here, Hartiala et al. identify two genetic loci for betaine levels on chromosomes 2q34 and 5q14.1 and find that the 2q34 locus was also associated with other pathway intermediates, and decreased risk of CAD in women.

Myeloperoxidase-Related Chlorination Activity Is Positively Associated with Circulating Ceruloplasmin in Chronic Heart Failure Patients: Relationship with Neurohormonal, Inflammatory, and Nutritional Parameters

Rationale. Heart failure (HF) is accompanied by the development of an imbalance between oxygen- and nitric oxide-derived free radical production leading to protein nitration. Both chlorinating and peroxidase cycle of Myeloperoxidase (MPO) contribute to oxidative and nitrosative stress and are involved in tyrosine nitration of protein. Ceruloplasmin (Cp) has antioxidant function through its ferroxidase I (FeO_xI) activity and has recently been proposed as a physiological defense mechanism against MPO inappropriate actions. Objective. We investigated the relationship between plasma MPO-related chlorinating activity, Cp and FeO_xI, and nitrosative stress, inflammatory, neurohormonal, and nutritional biomarkers in HF patients. Methods and Results. In chronic HF patients (n = 81, 76 ± 9 years, NYHA Class II (26); Class III (29); Class IV (26)) and age-matched controls (n = 17, 75 ± 11 years, CTR), plasma MPO chlorinating activity, Cp, FeO_xI, nitrated protein, free Malondialdehyde, BNP, norepinephrine, hsCRP, albumin, and prealbumin were measured. Plasma MPO chlorinating activity, Cp, BNP, norepinephrine, and hsCRP were increased in HF versus CTR. FeO_xI, albumin, and prealbumin were decreased in HF. MPO-related chlorinating activity was positively related to Cp (r = 0.363, P < 0.001), nitrated protein, hsCRP, and BNP and inversely to albumin. Conclusions. Plasma MPO chlorinated activity is increased in elderly chronic HF patients and positively associated with Cp, inflammatory, neurohormonal, and nitrosative parameters suggesting a role in HF progression.

Prognostic value of elevated serum ceruloplasmin levels in patients with heart failure

BACKGROUND

Ceruloplasmin (Cp) is a copper-binding acute-phase protein that is increased in inflammatory states and deficient in Wilson's disease. Recent studies demonstrate that increased levels of Cp are associated with increased risk of developing heart failure. Our objective was to test the hypothesis that serum Cp provides incremental and independent prediction of survival in stable patients with heart failure.

METHODS AND RESULTS

We measured serum Cp levels in 890 patients with stable heart failure undergoing elective cardiac evaluation that included coronary angiography. We examined the role of Cp levels in predicting survival over 5 years of follow-up. Mean Cp level was 26.6 ± 6.9 mg/dL and demonstrated relatively weak correlation with B-type natriuretic peptide (BNP; r = 0.187; P < .001). Increased Cp levels were associated with increased 5-year all-cause mortality (quartile [Q] 4 vs Q1 hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.4-2.8; P < .001). When controlled for coronary disease traditional risk factors, creatinine clearance, dialysis, body mass index, medications, history of myocardial infarction, BNP, left ventricular ejection fraction (LVEF), heart rate, QRS duration, left bundle branch blockage, and implantable cardioverter-defibrillator placement, higher Cp remained an independent predictor of increased mortality (Q4 vs Q1 HR 1.7, 95% CI 1.1-2.6; P < .05). Model quality was improved with addition of Cp to the aforementioned covariables (net reclassification improvement of 9.3%; P < .001).

CONCLUSIONS

Ceruloplasmin is an independent predictor of all-cause mortality in patients with heart failure. Measurement of Cp may help to identify patients at heightened mortality risk.

Genetic variation in iron metabolism is associated with neuropathic pain and pain severity in HIV-infected patients on antiretroviral therapy

HIV sensory neuropathy and distal neuropathic pain (DNP) are common, disabling complications associated with combination antiretroviral therapy (cART). We previously associated iron-regulatory genetic polymorphisms with a reduced risk of HIV sensory neuropathy during more neurotoxic types of cART. We here evaluated the impact of polymorphisms in 19 iron-regulatory genes on DNP in 560 HIV-infected subjects from a prospective, observational study, who underwent neurological examinations to ascertain peripheral neuropathy and structured interviews to ascertain DNP. Genotype-DNP associations were explored by logistic regression and permutation-based analytical methods. Among 559 evaluable subjects, 331 (59%) developed HIV-SN, and 168 (30%) reported DNP. Fifteen polymorphisms in 8 genes (p<0.05) and 5 variants in 4 genes (p<0.01) were nominally associated with DNP: polymorphisms in TF, TFRC, BMP6, ACO1, SLC11A2, and FXN conferred reduced risk (adjusted odds ratios [ORs] ranging from 0.2 to 0.7, all p<0.05); other variants in TF, CP, ACO1, BMP6, and B2M conferred increased risk (ORs ranging from 1.3 to 3.1, all p<0.05). Risks associated with some variants were statistically significant either in black or white subgroups but were consistent in direction. ACO1 rs2026739 remained significantly associated with DNP in whites (permutation p<0.0001) after correction for multiple tests. Several of the same iron-regulatory-gene polymorphisms, including ACO1 rs2026739, were also associated with severity of DNP (all p<0.05). Common polymorphisms in iron-management genes are associated with DNP and with DNP severity in HIV-infected persons receiving cART. Consistent risk estimates across population subgroups and persistence of the ACO1 rs2026739 association after adjustment for multiple testing suggest that genetic variation in iron-regulation and transport modulates susceptibility to DNP.

Meta-analysis and meta-regression analysis of biomarkers for abdominal aortic aneurysm

Background

Many studies have investigated the systemic and local expression of biomarkers in patients with abdominal aortic aneurysm (AAA). The natural history of AAA varies between patients, and predictors of the presence and diameter of AAA have not been determined consistently. The aim of this study was to perform a systematic review, meta-analysis and meta-regression of studies comparing biomarkers in patients with and without AAA, with the aim of summarizing the association of identified markers with both AAA presence and size.

Methods and results

Literature review identified 106 studies suitable for inclusion. Meta-analysis demonstrated a significant difference between matrix metalloproteinase (MMP) 9, tissue inhibitor of matrix metalloproteinase 1, interleukin (IL) 6, C-reactive protein (CRP), α1-antitrypsin, triglycerides, lipoprotein(a), apolipoprotein A and high-density lipoprotein in patients with and without AAA. Although meta-analysis was not possible for MMP-2 in aortic tissue, tumour necrosis factor α, osteoprotegerin, osteopontin, interferon γ, intercellular cell adhesion molecule 1 and vascular cell adhesion molecule 1, systematic review suggested an increase in these biomarkers in patients with AAA. Meta-regression analysis identified a significant positive linear correlation between aortic diameter and CRP level.

Conclusion

A wide variety of biomarkers are dysregulated in patients with AAA, but their clinical value is yet to be established. Future research should focus on the most relevant biomarkers of AAA, and how they could be used clinically.

Low serum ferroxidase I activity is associated with mortality in heart failure and related to both peroxynitrite-induced cysteine oxidation and tyrosine nitration of ceruloplasmin

RATIONALE

Ceruloplasmin antioxidant function is mainly related to its ferroxidase I (FeOxI) activity, which influences iron-dependent oxidative and nitrosative radical species generation. Peroxynitrite, whose production is increased in heart failure (HF), can affect ceruloplasmin antioxidant function through amino acid modification.

OBJECTIVE

We investigated the relationship between FeOxI and ceruloplasmin tyrosine and cysteine modification and explored in a cohort of patients with HF the potential clinical relevance of serum FeOxI.

METHODS AND RESULTS

In patients with chronic HF (n=96, 76 ± 9 years; New York Heart Association class, 2.9 ± 0.8) and age-matched controls (n=35), serum FeOxI, FeOxII, ceruloplasmin, nitrotyrosine-bound ceruloplasmin, B-type natriuretic peptide, norepinephrine, and high-sensitivity C-reactive protein were measured, and the patients were followed up for 24 months. Ceruloplasmin, B-type natriuretic peptide, norepinephrine, and high-sensitivity C-reactive protein were increased in HF versus controls. FeOxI was decreased in HF (-20%) and inversely related to nitrotyrosine-bound ceruloplasmin (r, -0.305; P=0.003). In HF, FeOxI lower tertile had a mortality rate doubled compared with middle-higher tertiles. FeOxI emerged as a mortality predictor (hazard ratio, 2.95; 95% confidence intervals [1.29-6.75]; P=0.011) after adjustment for age, sex, hypertension, smoking, sodium level, estimated glomerular filtration rate, and high-sensitivity C-reactive protein. In experimental settings, peroxynitrite incubation of serum samples and isolated purified ceruloplasmin reduced FeOxI activity while increasing ceruloplasmin tyrosine nitration and cysteine thiol oxidation. Reduced glutathione prevented peroxynitrite-induced FeOxI drop, tyrosine nitration, and cysteine oxidation; flavonoid(-)-epicatechin, which prevented ceruloplasmin tyrosine nitration but not cysteine oxidation, partially impeded peroxynitrite-induced FeOxI drop.

CONCLUSIONS

Reduced activity of serum FeOxI is associated with ceruloplasmin nitration and reduced survival in patients with HF. Both ceruloplasmin tyrosine nitration and cysteine thiol oxidation may be operant in vivo in peroxynitrite-induced FeOxI activity inhibition.

Plasma ceruloplasmin, a regulator of nitric oxide activity, and incident cardiovascular risk in patients with CKD

BACKGROUND AND OBJECTIVES

Increased serum levels of the acute-phase reactant ceruloplasmin predict adverse clinical outcomes in the setting of acute coronary syndromes and heart failure, but their role in patients with CKD is unclear. This study investigated the relationship of ceruloplasmin with clinical outcomes in CKD, especially with regard to traditional cardiac biomarkers.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Serum ceruloplasmin levels in consecutive study participants with CKD (n=654; estimated GFR<60 ml/min per 1.73 m(2)) as well as a control group of non-CKD participants matched for age and sex (n=250) were measured. Study participants were enrolled during 2001-2006 from a population of patients presenting for elective diagnostic coronary angiography and prospectively followed for 3 years (median follow-up=1095 days) to determine incident major adverse cardiac events (defined as a composite of death, nonfatal myocardial infarction, and stroke).

RESULTS

Serum ceruloplasmin levels in CKD patients were elevated versus controls (median [interquartile range]; 25.5 [21.8-29.6] versus 22.7 [19.7-26.5] mg/dl; P<0.001) and associated with increased risk of future major adverse cardiac events (hazard ratio, 1.35; 95% confidence interval, 1.0 to 1.82; P=0.04). After adjusting for traditional risk factors, higher serum ceruloplasmin was still associated with higher risk of major adverse cardiac events at 3 years (hazard ratio, 1.61; 95% confidence interval, 1.15 to 2.25; P=0.01).

CONCLUSION

In CKD patients, increased serum ceruloplasmin, a regulator of nitric oxide activity, is associated with increased risk of long-term adverse cardiovascular events, even after multivariable model adjustment for traditional clinical and biologic risk factors.

Transcriptional profiling of left ventricle and peripheral blood mononuclear cells in a rat model of postinfarction heart failure

Background

Myocardial infarction (MI) often results in left ventricular (LV) remodeling followed by heart failure (HF). It is of great clinical importance to understand the molecular mechanisms that trigger transition from compensated LV injury to HF and to identify relevant diagnostic biomarkers. The aim of this study was to investigate gene expression in the LV and to evaluate their reflection in peripheral blood mononuclear cells (PBMCs).

Methods

MI was induced in rats by ligation of the proximal left coronary artery. Rats with small, moderate, and large MI size were included into the experiment two months after the operation. The development of heart failure was estimated by echocardiography and catheterization. Microarrays were used to compare the LV and PBMCs transcriptomes of control and experimental animals.

Results

Only rats with a large MI developed extensive LV remodeling and heart failure. 840 transcripts were altered in LV of failing hearts, and especially numerous were those associated with the extracellular matrix. In contrast, no significant gene expression changes were seen in LVs of rats with moderate or small MI that had compensated LV injury. We showed that ceruloplasmin was similarly overexpressed in the heart and blood in response to HF, whereas downregulation of tetraspanin 12 was significant only in the PBMCs.

Conclusion

A large size of infarcted area is critical for progression of LV remodeling and HF development, associated with altered gene expression in the heart. Ceruloplasmin and tetraspanin 12 are potential convenient markers in readily obtainable PBMCs.

Myeloperoxidase, paraoxonase-1, and HDL form a functional ternary complex

Myeloperoxidase (MPO) and paraoxonase 1 (PON1) are high-density lipoprotein-associated (HDL-associated) proteins mechanistically linked to inflammation, oxidant stress, and atherosclerosis. MPO is a source of ROS during inflammation and can oxidize apolipoprotein A1 (APOA1) of HDL, impairing its atheroprotective functions. In contrast, PON1 fosters systemic antioxidant effects and promotes some of the atheroprotective properties attributed to HDL. Here, we demonstrate that MPO, PON1, and HDL bind to one another, forming a ternary complex, wherein PON1 partially inhibits MPO activity, while MPO inactivates PON1. MPO oxidizes PON1 on tyrosine 71 (Tyr71), a modified residue found in human atheroma that is critical for HDL binding and PON1 function. Acute inflammation model studies with transgenic and knockout mice for either PON1 or MPO confirmed that MPO and PON1 reciprocally modulate each other's function in vivo. Further structure and function studies identified critical contact sites between APOA1 within HDL, PON1, and MPO, and proteomics studies of HDL recovered from acute coronary syndrome (ACS) subjects revealed enhanced chlorotyrosine content, site-specific PON1 methionine oxidation, and reduced PON1 activity. HDL thus serves as a scaffold upon which MPO and PON1 interact during inflammation, whereupon PON1 binding partially inhibits MPO activity, and MPO promotes site-specific oxidative modification and impairment of PON1 and APOA1 function.

Ceruloplasmin and heart failure in the Atherosclerosis Risk in Communities study

BACKGROUND

Ceruloplasmin (Cp) decreases nitric oxide bioavailability in blood and has been associated with cardiovascular disease (CVD) in clinical studies. We assessed the associations between Cp and incident heart failure (HF), death, and CVD in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS AND RESULTS

Cp was measured at ARIC visit 4 (1996-1998). We studied 9240 individuals without HF or CVD at ARIC visit 4 and followed them for a mean of 10.5 years. Genome-wide association study was performed to identify genetic determinants of Cp levels and evaluate their association with incident HF in ARIC participants. Cp levels (mean±SD) were higher in women versus men (335±79 versus 258±44 mg/L; P<0.0001), women on versus not on hormone-replacement therapy (398±89 versus 291±60 mg/L; P<0.0001), and African Americans versus whites (299±63 versus 293±74 mg/L; P=0.0005). After adjusting for traditional risk factors, high-sensitivity C-reactive protein, N-terminal pro-B-type natriuretic peptide, and high-sensitivity cardiac troponin T, higher levels of Cp were associated with HF (hazard ratio, 1.44; 95% confidence interval, 1.13-1.83) and mortality (hazard ratio, 1.38; 95% confidence interval, 1.11-1.63). A locus on the ceruloplasmin gene on chromosome 3 was significantly associated with Cp levels (normal 295.56±77.60 mg/L; heterozygote 316.72±88.02 mg/L; homozygote 331.04±85.40 mg/L; P=8.3×10(-13)) but not with incident HF. After adjustment for traditional risk factors, Cp levels were also weekly associated with CVD.

CONCLUSIONS

Cp was associated with incident HF, mortality, and CVD in the ARIC population. A single locus on chromosome 3 was associated with Cp levels but not with HF.

Diminished antioxidant activity of high-density lipoprotein-associated proteins in chronic kidney disease

Background

Decreased serum arylesterase activity, catalyzed by the high‐density lipoprotein–associated paraoxonase (PON)‐1, is associated with increased oxidant stress and atherosclerosis risk. We sought to determine the prognostic value of serum PON‐1 activity, as monitored by PON or arylesterase activities, in subjects with chronic kidney disease (CKD), particularly in relation to established cardiac biomarkers.

Methods and Results

Serum arylesterase and PON activities were measured in sequential subjects with CKD (n=630; estimated glomerular filtration rate [eGFR] <60 mL/min per 1.73 m²) and an age‐ and sex‐matched control group of non‐CKD subjects (n=315) presenting for cardiac evaluations and prospectively followed for incident (3‐year) major adverse cardiac events (composite of death, nonfatal myocardial infarction, and stroke). Serum arylesterase activity in CKD subjects was lower compared with that in non‐CKD control subjects [median (interquartile range) 94 (77 to 112) versus 103 (85 to 121) μmol(L·min) per mL, P<0.001]; similarly, PON activity in CKD subjects was lower compared with that in non‐CKD control subjects [median (interquartile range) 474 (275 to 936) versus 586 (301 to 1118) nmol(L·min) per mL, P<0.001]. Lower serum arylesterase (hazard ratio 1.8, 95% CI 1.26 to 2.57, P<0.01) was a predictor of poorer outcomes. After adjusting for traditional risk factors and medication use, lower serum arylesterase (hazard ratio 1.55, 95% CI 1.08 to 2.23, P<0.05) still conferred an increased risk of major adverse cardiac events at 3 years.

Conclusions

In patients with CKD, decreased serum arylesterase activity, a measure of diminished antioxidant properties of PON‐1, predicts higher risk of incident long‐term adverse cardiovascular events (heart attack, stroke, or death) in multivariable models adjusting for established clinical and biochemical risk factors.

Computational biomarker pipeline from discovery to clinical implementation: plasma proteomic biomarkers for cardiac transplantation

Recent technical advances in the field of quantitative proteomics have stimulated a large number of biomarker discovery studies of various diseases, providing avenues for new treatments and diagnostics. However, inherent challenges have limited the successful translation of candidate biomarkers into clinical use, thus highlighting the need for a robust analytical methodology to transition from biomarker discovery to clinical implementation. We have developed an end-to-end computational proteomic pipeline for biomarkers studies. At the discovery stage, the pipeline emphasizes different aspects of experimental design, appropriate statistical methodologies, and quality assessment of results. At the validation stage, the pipeline focuses on the migration of the results to a platform appropriate for external validation, and the development of a classifier score based on corroborated protein biomarkers. At the last stage towards clinical implementation, the main aims are to develop and validate an assay suitable for clinical deployment, and to calibrate the biomarker classifier using the developed assay. The proposed pipeline was applied to a biomarker study in cardiac transplantation aimed at developing a minimally invasive clinical test to monitor acute rejection. Starting with an untargeted screening of the human plasma proteome, five candidate biomarker proteins were identified. Rejection-regulated proteins reflect cellular and humoral immune responses, acute phase inflammatory pathways, and lipid metabolism biological processes. A multiplex multiple reaction monitoring mass-spectrometry (MRM-MS) assay was developed for the five candidate biomarkers and validated by enzyme-linked immune-sorbent (ELISA) and immunonephelometric assays (INA). A classifier score based on corroborated proteins demonstrated that the developed MRM-MS assay provides an appropriate methodology for an external validation, which is still in progress. Plasma proteomic biomarkers of acute cardiac rejection may offer a relevant post-transplant monitoring tool to effectively guide clinical care. The proposed computational pipeline is highly applicable to a wide range of biomarker proteomic studies.

Aspirin hydrolysis in plasma is a variable function of butyrylcholinesterase and platelet-activating factor acetylhydrolase 1b2 (PAFAH1b2)

Aspirin is rapidly hydrolyzed within erythrocytes by a heterodimer of PAFAH1b2/PAFAH1b3 but also in plasma by an unidentified activity. Hydrolysis in both compartments was variable, with a 12-fold variation in plasma among 2226 Cleveland Clinic GeneBank patients. Platelet inhibition by aspirin was suppressed in plasma that rapidly hydrolyzed aspirin. Plasma aspirin hydrolysis was significantly higher in patients with coronary artery disease compared with control subjects (16.5 ± 4.4 versus 15.1 ± 3.7 nmol/ml/min; p = 3.4 × 10(-8)). A genome-wide association study of 2054 GeneBank subjects identified a single locus immediately adjacent to the BCHE (butyrylcholinesterase) gene associated with plasma aspirin hydrolytic activity (lead SNP, rs6445035; p = 9.1 × 10(-17)). However, its penetrance was low, and plasma from an individual with an inactivating mutation in BCHE still effectively hydrolyzed aspirin. A second aspirin hydrolase was identified in plasma, the purification of which showed it to be homomeric PAFAH1b2. This is distinct from the erythrocyte PAFAH1b2/PAFAH1b3 heterodimer. Inhibitors showed that both butyrylcholinesterase (BChE) and PAFAH1b2 contribute to aspirin hydrolysis in plasma, with variation primarily reflecting non-genetic variation of BChE activity. Therefore, aspirin is hydrolyzed in plasma by two enzymes, BChE and a new extracellular form of platelet-activating factor acetylhydrolase, PAFAH1b2. Hydrolytic effectiveness varies widely primarily from non-genetic variation of BChE activity that affects aspirin bioavailability in blood and the ability of aspirin to inhibit platelet aggregation.

Ceruloplasmin is an endogenous inhibitor of myeloperoxidase

Myeloperoxidase is a neutrophil enzyme that promotes oxidative stress in numerous inflammatory pathologies. It uses hydrogen peroxide to catalyze the production of strong oxidants including chlorine bleach and free radicals. A physiological defense against the inappropriate action of this enzyme has yet to be identified. We found that myeloperoxidase oxidized 75% of the ascorbate in plasma from ceruloplasmin knock-out mice, but there was no significant loss in plasma from wild type animals. When myeloperoxidase was added to human plasma it became bound to other proteins and was reversibly inhibited. Ceruloplasmin was the predominant protein associated with myeloperoxidase. When the purified proteins were mixed, they became strongly but reversibly associated. Ceruloplasmin was a potent inhibitor of purified myeloperoxidase, inhibiting production of hypochlorous acid by 50% at 25 nm. Ceruloplasmin rapidly reduced Compound I, the Fe(V) redox intermediate of myeloperoxidase, to Compound II, which has Fe(IV) in its heme prosthetic groups. It also prevented the fast reduction of Compound II by tyrosine. In the presence of chloride and hydrogen peroxide, ceruloplasmin converted myeloperoxidase to Compound II and slowed its conversion back to the ferric enzyme. Collectively, our results indicate that ceruloplasmin inhibits myeloperoxidase by reducing Compound I and then trapping the enzyme as inactive Compound II. We propose that ceruloplasmin should provide a protective shield against inadvertent oxidant production by myeloperoxidase during inflammation.

Association between serum ceruloplasmin levels and arterial stiffness in Korean men with type 2 diabetes mellitus

BACKGROUND

Increased oxidative stress contributes to the development of arterial stiffness. Arterial stiffness, as measured by brachial-ankle pulse wave velocity (baPWV), has been known to be correlated with oxidative stress. Serum ceruloplasmin (CP), a copper-carrying protein, may indicate the overall level of oxidative stress in the body. The present study investigated whether serum CP levels are associated with baPWV in Korean men with type 2 diabetes mellitus (DM).

SUBJECTS AND METHODS

Serum CP levels and conventional risk factors were measured in 760 Korean men with type 2 DM. Arterial stiffness was assessed by baPWV obtained with an automatic device (model VP-1000; Colin, Komaki, Japan).

RESULTS

Correlation analysis indicated a significant positive association between serum CP and baPWV (r = 0.109, P = 0.003). Age-adjusted baPWV increased gradually according to serum CP quartiles (Q1, 1,500.3 ± 18.4 cm/s; Q2, 1,511.6 ± 17.8 cm/s; Q3, 1,551.8 ± 17.9 cm/s; Q4, 1,622.1 ± 17.8 cm/s; P for trend < 0.001). Multivariate linear regression analysis showed that serum CP was independently associated with baPWV in various models.

CONCLUSIONS

A positive relationship was identified between CP and baPWV in adult male subjects with type 2 DM, which was independent of conventional cardiovascular risk factors. Further studies are needed to confirm whether CP contributes to the pathogenesis of increased arterial stiffness in subjects with type 2 DM.

Association of a genetic risk score with prevalent and incident myocardial infarction in subjects undergoing coronary angiography

BACKGROUND

Genome-wide association studies have identified multiple variants associating with coronary artery disease (CAD) and myocardial infarction (MI). Whether a combined genetic risk score (GRS) is associated with prevalent and incident MI in high-risk subjects remains to be established.

METHODS AND RESULTS

In subjects undergoing cardiac catheterization (n=2597), we identified cases with a history of MI onset at age <70 years and controls ≥70 years without prior MI and followed them for incident MI and death. Genotyping was performed for 11 established CAD/MI variants, and a GRS was calculated based on average number of risk alleles carried at each locus weighted by effect size. Replication of association findings was sought in an independent angiographic cohort (n=2702). The GRS was significantly associated with prevalent MI, occurring before age 70, compared with older controls (≥70 years of age) with no history of MI (P<0.001). This association was successfully replicated in a second cohort, yielding a pooled P value of <0.001. The GRS modestly improved the area-under-the-curve statistic in models of prevalent MI with traditional risk factors; however, the association was not statistically significant when elderly controls without MI but with s\ angiographic CAD were examined (pooled P=0.11). Finally, during a median 2.5-year follow-up, only a nonsignificant trend was noted between the GRS and incident events, which was also not significant in the replication cohort.

CONCLUSIONS

A GRS of 11 CAD/MI variants is associated with prevalent MI but not near-term incident adverse events in 2 independent angiographic cohorts. These findings have implications for understanding the clinical use of genetic risk scores for secondary as opposed to primary risk prediction.