The effects of nitric oxide-oxidase and putative glutathione-peroxidase activities of ceruloplasmin on the viability of cardiomyocytes exposed to hydrogen peroxide

Effects of antipsychotics on antioxidant defence system in patients with schizophrenia: A meta-analysis

Theory of oxidative stress is suggested in the pathophysiology of schizophrenia. To determine the cause of impaired antioxidant defense system in schizophrenia, a meta-analysis was performed by selecting studies published from 1964 to 2021 from Pubmed and Scopus databases. Data were analysed using Comprehensive Meta-Analysis version 2 and calculated effect sizes were compared between unmedicated and medicated patients with schizophrenia and healthy controls. Heterogeneity, publication bias assessments and subgroup analyses of drug-free and drug-naïve patients, and patients treated with atypical and typical antipsychotics were conducted. Subgroup analysis of confounding factors including age, gender, illness duration and patient status was also conducted. We found that glutathione peroxidase (GPx) was significantly decreased in all patients. Significantly lower catalase (CAT), glutathione (GSH) and albumin (ALB) were found in unmedicated patients only. Both groups showed significantly weakened non-enzymatic antioxidant capacity. Subgroup analyses indicated that weakened non-enzymatic antioxidant capacity may be associated with schizophrenia. Antioxidant status was more impaired in drug-free patients compared with other subgroups. This indicated that antipsychotics may improve antioxidant defense system. Although effect sizes were smaller, future studies may focus on the effect of antipsychotic discontinuation. In overall, schizophrenia was associated with impaired antioxidant defense system especially the non-enzymatic antioxidant system.

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.

Inhibition of p16INK4A to Rejuvenate Aging Human Cardiac Progenitor Cells via the Upregulation of Anti-oxidant and NFκB Signal Pathways

Autologous human cardiac stem/progenitor cell (hCPC) therapy is a promising treatment that has come into use in recent years for patients with cardiomyopathy. Though innovative in theory, a major hindrance to the practical application of this treatment is that the hCPCs of elderly patients, who are most susceptible to myocardial disease, are senescent and prone to cell death. Rejuvenating hCPCs from elderly patients may help overcome this obstacle, and can be accomplished by reversing entry into the cellular stage of senescence. p16^INK4A, a cyclin dependent kinase inhibitor, is an important player in the regulation of cell senescence. In this study, we investigated whether knockdown of p16^INK4A will rejuvenate aging hCPCs to a youthful phenotype. Our data indicated that upregulation of p16^INK4A is associated with hCPC senescence. Both cell proliferation and survival capacity were significantly increased in hCPCs infected with lentivirus expressing p16^INK4A shRNA when compared to control hCPCs. The knockdown of p16^INK4A also induced antioxidant properties as indicated by a 50% decrease in ROS generation at basal cell metabolism, and a 25% decrease in ROS generation after exposure to oxidative stress. Genes associated with cell senescence (p21^CIP1), anti-apoptosis (BCL2 and MCL1), anti-oxidant (CYGB, PRDX1 and SRXN1), and NFκB signal pathway (p65, IKBKB, HMOX1, etc.), were significantly upregulated after the p16^INK4A knockdown. Knocking down the NFĸB-p65 expression also significantly diminished the cytoprotective effect caused by the p16^INK4A knockdown. Our results suggest that genetic knockdown of p16^INK4A may play a significant role in inducing antioxidant effects and extending lifespan of aging hCPCs. This genetic modification may enhance the effectiveness of autologous hCPC therapy for repair of infarcted myocardium.

Endogenous non-enzymatic antioxidants in the human body

The exposure of cells, tissues and extracellular matrix to harmful reactive species causes a cascade of reactions and induces activation of multiple internal defence mechanisms (enzymatic or non-enzymatic) that provide removal of reactive species and their derivatives. The non-enzymatic antioxidants are represented by molecules characterized by the ability to rapidly inactivate radicals and oxidants. This paper focuses on the major intrinsic non-enzymatic antioxidants, including metal binding proteins (MBPs), glutathione (GSH), uric acid (UA), melatonin (MEL), bilirubin (BIL) and polyamines (PAs).

Postprandial lipids accelerate and redirect nitric oxide consumption in plasma

Nitric oxide (NO) and O2 are both three-to four-fold more soluble in biological lipids than in aqueous solutions. Their higher concentration within plasma lipids accelerates NO autoxidation to an extent that may be of importance to overall NO bioactivity. This study was undertaken to test the hypothesis that increased plasma lipids after a high-fat meal appreciably accelerate NO metabolism and alter the byproducts formed. We found that plasma collected from subjects after consumption of a single high-fat meal had a higher capacity for NO consumption and consumed NO more rapidly compared to fasting plasma. This increased NO consumption showed a direct correlation with plasma triglyceride concentrations (p = 0.006). The accelerated NO consumption in postprandial plasma was reversed by removal of the lipids from the plasma, was mimicked by the addition of hydrophobic micelles to aqueous buffer, and could not be explained by the presence of either free hemoglobin or ceruloplasmin. The products of NO consumption were shifted in postprandial plasma, with 55% more nitrite (n = 12, p = 0.002) but 50% less SNO (n = 12, p = 0.03) production compared to matched fasted plasma. Modeling calculations indicated that NO autoxidation was accelerated by about 48-fold in the presence of plasma lipids. We conclude that postprandial triglyceride-rich lipoproteins exert a significant influence on NO metabolism in plasma.

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.

Association of serum arginase I with L-arginine, 3-nitrotyrosine, and exhaled nitric oxide in healthy Japanese workers

The associations of serum arginase I with serum L-arginine, serum 3-nitrotyrosine, and fractional exhaled nitric oxide (FENO) were evaluated cross-sectionally in healthy Japanese workers. The serum median (minimum-maximum) levels of arginase I, 3-nitrotyrosine, and FENO in healthy people (n = 130) were 14.6 (0.94-108.1) ng/mL, 81.0 (0.27-298.6) pmol/mg protein, and 14.0 (5.0-110.0) parts per billion, respectively. Significant correlations of arginase I with FENO, L-arginine, 3-nitrotyrosine, and percent predicted forced expiratory volume in 1 s (FEV1 (% predicted)) were observed, and correlations of FENO with immunoglobulin E (IgE), NOx, arginase I, and sex and allergy were also observed. By multiple regression analysis, arginase I showed positive associations with FENO and 3-nitrotyrosine, and a negative association with L-arginine; and FENO showed positive associations with IgE and NO2(-) + NO3(-) (NOx), and a negative association with L-arginine, as well as an association with sex. Moreover, logistic regression analysis showed linear inverse associations of arginase I and 3-nitrotyrosine with L-arginine, and showed linear positive associations of FENO with IgE and NOx. It was concluded that serum arginase I might regulate serum L-arginine and 3-nitrotyrosine via L-arginine, and that IgE or NOx might regulate FENO in a healthy Japanese population.

Role of ceruloplasmin in nitric oxide metabolism in plasma of humans and sheep: a comparison of adults and fetuses

Nitric oxide (NO) is metabolized in plasma, in part by the ferroxidase ceruloplasmin (Cp), to form nitrite and nitrosothiols (SNOs), which are proposed to mediate protective responses to hypoxia and ischemia. We hypothesized that NO metabolism would be attenuated in fetal plasma due to low Cp activity. We measured Cp concentrations and activity in plasma samples collected from adults and fetuses of humans and sheep. We then added NO ([NO]: 1.5 or 100 μM) to plasma and aqueous buffer and measured rates of NO disappearance and the production of nitrite and SNO. Cp concentrations in fetal plasma were <15% of adult levels. In aqueous buffer, 1.5 μM NO disappeared with a half-life of 347 ± 64 s (means ± SE) but in plasma of humans the half-life was 19 ± 2 s (adult) and 11 ± 1 s (fetus, P = 0.004) and in sheep it was 31 ± 3 s (adult) and 43 ± 5 s (fetus, P = 0.04). Cp activity was not correlated with the overall elimination half-life of NO or with the amount of SNO ([NO]: 100 μM) or nitrite ([NO]: 1.5 or 100 μM) produced but correlated with SNO yields at 1.5 μM [NO] (r = 0.92, P = 0.04). Our data demonstrate that Cp is not essential to the increased rate of metabolism of NO in plasma relative to aqueous buffers and that it is not essential to the production of nitrite from NO. Cp may be involved in the conversion of NO to SNO in plasma under near-physiological concentrations of NO.

Ceruloplasmin is a potential biomarker for aGvHD following allogeneic hematopoietic stem cell transplantation

Acute graft-versus-host-disease (aGvHD) is the major cause of non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recently, diagnostic biomarkers for aGvHD have been shown to play important roles in evaluating disease status and mortality risk after allo-HSCT. To identify plasma biomarkers for aGvHD with high sensitivity and specificity, a quantitative proteomic approach using 8-plex isobaric tags for relative and absolute quantitation (8-plex iTRAQ) was employed to screen differentially expressed proteins in peripheral blood before and after the onset of aGvHD. Four target proteins, ceruloplasmin (CP), myeloperoxidase (MPO), complement factor H (CFH), and alpha-1-acid glycoprotein (AGP), were chosen for preliminary validation with enzyme linked immunosorbent assay (ELISA) in 20 paired samples at both the time of diagnosis of aGvHD and the time of complete response. The most promising candidate, ceruloplasmin, was further validated at fixed time points after allo-HSCT and during aGvHD. The plasma ceruloplasmin levels were significantly increased during the period of aGvHD onset and were markedly decreased as aGvHD resolved. The plasma ceruloplasmin levels at different time points post-transplant in the aGvHD (+) group were significantly higher than those in the aGvHD (-) group (p<0.001). The elevation of ceruloplasmin level in patients with active aGvHD was independent of infection status. Patients whose ceruloplasmin levels were elevated above 670 μg/ml at 7, 14 and 21 days after allo-HSCT had a remarkably increased probability of subsequently developing aGvHD. In conclusion, our results suggest that plasma ceruloplasmin is a potential plasma biomarker of aGvHD, and it also has prognostic value for risk-adapted prophylaxis during the consecutive time points monitored in the first month after allo-HSCT.

The role of metal regulatory proteins in brain oxidative stress: a tutorial

The proteins that regulate the metabolism of a metal must also play a role in regulating the redox activity of the metal. Metals are intrinsic to a substantial number of biological processes and the proteins that regulate those activities are also considerable in number. The role these proteins play in a wide range of physiological processes involves them directly and indirectly in a variety of disease processes. Similarly, it may be therapeutically advantageous to pharmacologically alter the activity of these metal containing proteins to influence disease processes. This paper will introduce the reader to a number of important proteins in both metal metabolism and oxidative stress, with an emphasis on the brain. Potential pharmacological targets will be considered.

Heme/copper assembly mediated nitrite and nitric oxide interconversion

The heme(a3)/Cu(B) active site of cytochrome c oxidase is responsible for cellular nitrite reduction to nitric oxide; the same center can return NO to the nitrite pool via oxidative chemistry. Here, we show that a partially reduced heme/Cu assembly reduces NO(2)(-) ion, producing nitric oxide. The heme serves as the reductant, but the Cu(II) ion is also required. In turn, a μ-oxo heme-Fe(III)-O-Cu(II) complex facilitates NO oxidation to nitrite; the final products are the reduced heme and Cu(II)-nitrito complexes.

Resveratrol protects adult cardiomyocytes against oxidative stress mediated cell injury

Recent studies from our laboratory have showed that resveratrol, a polyphenol found predominantly in grapes rendered strong cardioprotection in animal models of heart disease. The cardioprotection which was observed was primarily associated with the ability of resveratrol to reduce oxidative stress in these models. The aim of the current study was to corroborate the role of resveratrol as an inhibitor of oxidative stress and explore the underlying mechanisms of its action in heart disease. For this purpose, we used a cell model of oxidative stress, the hydrogen peroxide (H(2)O(2)) exposed adult rat cardiomyocytes, which was treated with and without resveratrol (30 μM); cardiomyocytes which were not exposed to resveratrol served as controls. Cell injury, cell death and oxidative stress measurements as well as the activities of the major endogenous antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were carried out in control and H(2)O(2) exposed cardiomyocytes, treated with and without resveratrol. Pharmacological blockade using specific blockers of the antioxidant enzymes were used to confirm their role in mediating resveratrol action in H(2)O(2) exposed cardiomyocytes. The status of H(2)O(2) and antioxidant enzymes in serum samples from spontaneously hypertensive rats (SHR) treated with and without resveratrol (2.5 mg/kg body weight) was also examined. Our results showed significant cell injury and death in H(2)O(2) exposed cardiomyocytes which was prevented upon resveratrol treatment. SOD and CAT activities were decreased in H(2)O(2) exposed adult rat cardiomyocytes; treatment with resveratrol significantly prevented this reduction. However, GPx activity was not altered in the H(2)O(2) exposed cardiomyocytes in comparison to controls. Pharmacological blockade of SOD and/or CAT prevented the beneficial effect of resveratrol. In SHR, H(2)O(2) levels were increased, but CAT activity was decreased, while SOD remained unchanged, when compared to WKY rats; resveratrol treatment significantly prevented the increase in H(2)O(2) levels and the decrease in CAT activities in SHR. Based on our results, we conclude that treatment with resveratrol prevents oxidative stress induced cardiomyocyte injury mainly by preserving the activities of critical antioxidant enzymes. This may be a crucial mechanism by which resveratrol confers cardioprotection.

Clinical and genetic association of serum ceruloplasmin with cardiovascular risk

OBJECTIVE

Ceruloplasmin (Cp) is an acute-phase reactant that is increased in inflammatory diseases and in acute coronary syndromes. Cp has recently been shown to possess nitric oxide (NO) oxidase catalytic activity, but its impact on long-term cardiovascular outcomes in stable cardiac patients has not been explored.

METHODS AND RESULTS

We examined serum Cp levels and their relationship with incident major adverse cardiovascular events (MACE; death, myocardial infarction [MI], stroke) over 3-year follow-up in 4177 patients undergoing elective coronary angiography. We also carried out a genome-wide association study to identify the genetic determinants of serum Cp levels and evaluate their relationship to prevalent and incident cardiovascular risk. In our cohort (age 63±11 years, 66% male, 32% history of MI, 31% diabetes mellitus), mean Cp level was 24±6 mg/dL. Serum Cp level was associated with greater risk of MI at 3 years (hazard ratio [quartile 4 versus 1] 2.35, 95% confidence interval [CI] 1.79-3.09, P<0.001). After adjustment for traditional risk factors, high-sensitivity C-reactive protein, and creatinine clearance, Cp remained independently predictive of MACE (hazard ratio 1.55, 95% CI 1.10-2.17, P=0.012). A 2-stage genome-wide association study identified a locus on chromosome 3 over the CP gene that was significantly associated with Cp levels (lead single-nucleotide polymorphism rs13072552; P=1.90×10(-11)). However, this variant, which leads to modestly increased serum Cp levels (≈1.5-2 mg/dL per minor allele copy), was not associated with coronary artery disease or future risk of MACE.

CONCLUSIONS

In stable cardiac patients, serum Cp provides independent risk prediction of long-term adverse cardiac events. Genetic variants at the CP locus that modestly affect serum Cp levels are not associated with prevalent or incident risk of coronary artery disease in this study population.