The use of myeloperoxidase as a risk marker for atherosclerosis

Propofol metabolites and derivatives inhibit the oxidant activities of neutrophils and myeloperoxidase

In previous studies, propofol has shown immunomodulatory abilities on various in vitro models. As this anesthetic molecule is extensively used in intensive care units, its anti-inflammatory properties present a great interest for the treatment of inflammatory disorders like the systemic inflammatory response syndrome. In addition to its inhibition abilities on important neutrophils mechanisms (chemotaxis, reactive oxygen species (ROS) production, Neutrophil Extracellular Traps (NETs) formation, …), our group has shown that propofol is also a reversible inhibitor of the oxidant myeloperoxidase (MPO) activity. Propofol being subject to rapid metabolism, its derivatives could contribute to its anti-inflammatory action. First, propofol-β-glucuronide (PPFG), 2,6-diisopropyl-1,4-p-benzoquinone (PPFQ) and 3,5,3',5'-tetraisopropyl-(4,4')-diphenoquinone (PPFDQ) were compared on their superoxide (O₂^.-) scavenging properties and more importantly on their inhibitory action on the O₂^.- release by activated neutrophils using EPR spectroscopy and chemiluminescence assays. PPFQ and PPFDQ are potent superoxide scavengers and also inhibit the release of ROS by neutrophils. An Enzyme-Linked Immunosorbent Assay (ELISA) has also highlighted the ability of both molecules to significantly decrease the MPO degranulation process of neutrophils. Fluorescence enzymatic assays helped to investigate the action of the propofol derivatives on the peroxidase and chlorination activities of MPO. In addition, using SIEFED (Specific Immunological Extraction Followed by Enzyme Detection) assays and docking, we demonstrated the concentration-dependent inhibitory action of PPFQ and its ability to bind to the enzyme active site while PPFG presented a much weaker inhibitory action. Overall, the oxidation derivatives and metabolites PPFQ and PPFDQ can, at physiological concentrations, perpetuate the immunomodulatory action of propofol by acting on the oxidant response of PMN and MPO.

The Relationship between Selected Inflammation and Oxidative Stress Biomarkers and Carotid Intima-Media Thickness (IMT) Value in Youth with Type 1 Diabetes Co-Existing with Early Microvascular Complications

Recent years have confirmed the importance of oxidative stress and biomarkers of inflammation in estimating the risk of cardiovascular disease (CVD) and explaining not fully understood pathogenesis of diabetic macroangiopathy. We aimed to analyze the relation between the intima-media thickness (IMT) of common carotid arteries and the occurrence of classical cardiovascular risk factors, together with the newly proposed biomarkers of CVD risk (high-sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO), adiponectin, N-terminal-pro B-type natriuretic peptide (NT-proBNP) and vitamin D) in youth with type 1 diabetes (T1D) recognized in screening tests to present early stages of microvascular complications (VC). The study group consisted of 50 adolescents and young adults with T1D, mean age 17.1 years (10–26 age range), including 20 patients with VC (+) and 30 VC (−). The control group (Control) consisted of 22 healthy volunteers, mean age 16.5 years (11–26 age range). In the VC (+) patients, we found a significantly higher concentration of HbA1c, lipid levels, hsCRP and NT-proBNP. BMI and blood pressure values were highest in the VC (+) group. Higher levels of MPO and lower levels of vitamin D were found in both diabetic groups vs. Control. IMT in VC (+) patients was significantly higher and correlated positively with HbA1c, hsCRP, NT-pro-BNP and negatively with vitamin D levels. In conclusion, youth with T1D and VC (+) present many abnormalities in the classical and new CVD biomarkers. hsCRP and MPO seem to be the most important markers for estimating the risk of macroangiopathy. NT-proBNP may present a possible marker of early myocardial injury in this population.

Changes of Metabolic Biomarker Levels upon One-Year Anti-TNF-α Therapy in Rheumatoid Arthritis and Ankylosing Spondylitis: Associations with Vascular Pathophysiology

Background: Cardiovascular (CV) morbidity, mortality, and metabolic syndrome are associated with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Here, lipids and other metabolic markers in relation to vascular function and clinical markers were evaluated in RA and AS patients undergoing one-year anti-TNF therapy. Patients and methods: Fifty-three patients including 36 RA patients treated with either etanercept (ETN) or certolizumab pegol (CZP) and 17 AS patients treated with ETN were included in a 12-month follow-up study. Various lipids, paraoxonase (PON) and arylesterase (ARE) activities, myeloperoxidase (MPO) and adipokine levels were determined overtime. Ultrasonography was performed to determine flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT), and arterial pulse-wave velocity (PWV) in all patients. All assessments were performed at baseline and 6 and 12 months after treatment initiation. Results: Anti-TNF therapy decreased ARE activity, MPO, adiponectin, and chemerin levels after 12 months (p < 0.05). Lipids, PON activity, and leptin remained unchanged. Regression analyses suggested variable associations of IMT, PWV, and FMD with ARE, MPO, leptin, and lipids (p < 0.05). On the other hand, these metabolic parameters were significantly associated with disease duration, CV history, CRP, obesity, PWV, and IMT (p < 0.05). One-year anti-TNF treatment together with baseline leptin (p = 0.039) or CRP (p = 0.016) levels determined 12 months of lipid changes overtime. TNF inhibition together with baseline disease activity determined ARE activity changes (p = 0.046). Anti-TNF therapy and baseline chemerin levels determined IMT changes overtime (p = 0.003). Conclusions: Assessment of various metabolic parameters together with disease activity, CRP, and ultrasound-based techniques may exert additional value in determining CV burden and in monitoring the effects of biologics on preclinical vascular pathophysiology.

Redox Regulation of Inflammatory Processes Is Enzymatically Controlled

Redox regulation depends on the enzymatically controlled production and decay of redox active molecules. NADPH oxidases, superoxide dismutases, nitric oxide synthases, and others produce the redox active molecules superoxide, hydrogen peroxide, nitric oxide, and hydrogen sulfide. These react with target proteins inducing spatiotemporal modifications of cysteine residues within different signaling cascades. Thioredoxin family proteins are key regulators of the redox state of proteins. They regulate the formation and removal of oxidative modifications by specific thiol reduction and oxidation. All of these redox enzymes affect inflammatory processes and the innate and adaptive immune response. Interestingly, this regulation involves different mechanisms in different biological compartments and specialized cell types. The localization and activity of distinct proteins including, for instance, the transcription factor NFκB and the immune mediator HMGB1 are redox-regulated. The transmembrane protein ADAM17 releases proinflammatory mediators, such as TNFα, and is itself regulated by a thiol switch. Moreover, extracellular redox enzymes were shown to modulate the activity and migration behavior of various types of immune cells by acting as cytokines and/or chemokines. Within this review article, we will address the concept of redox signaling and the functions of both redox enzymes and redox active molecules in innate and adaptive immune responses.

Does the use of acetylsalicylic acid have an influence on our vision?

PURPOSE

Acetylsalicylic acid (ASA) is one of the most commonly used drugs in the world due to its anti-inflammatory, analgesic, and antipyretic properties. This review aims to describe the relationship between acetylsalicylic acid and age-related macular degeneration (AMD) - a chronic disease that causes deterioration of visual acuity and is one of the most common ophthalmological diseases these days.

METHODS

Data presented in this review were collected from both research and review articles concerning ophthalmology and pharmacology.

RESULTS

The results of the studies analyzed in this review are not unambiguous. Moreover, the studies are not homogenous. They differed from one another in terms of the number of patients, the age criteria, the ASA dose, and the duration of control period. The reviewed studies revealed that ASA therapy, which is applied as a protection in cardiovascular diseases in patients with early forms of AMD and geographic atrophy, should not be discontinued.

CONCLUSION

On the basis of the present studies, it cannot be unequivocally said whether ASA influences people's vision and if people endangered with AMD progression or who are diagnosed with AMD should use this drug. It may increase the risk of AMD, but it can also reduce the risk of life-threatening conditions. The authors suggest that in order to avoid possible risks of AMD development, people who frequently take ASA should have their vision checked regularly.

Actinidia arguta supplementation protects aorta and liver in rats with induced hypercholesterolemia

There are no published results focusing on the study of hardy kiwifruit as a supplementation to the atherogenic diet. We hypothesized that hardy kiwifruit (Actinidia arguta (A. arguta)) from Poland possess better pro-healthy action than two Asian varieties (Hayward and Bidan). We tested this hypothesis by measuring the metabolic reactions of rats loaded with 1% cholesterol and supplemented with 5% of hardy kiwifruit (A. arguta), Hayward, or Bidan in their diets. The experiment was performed on 71 male Wistar rats. Cholesterol showed a significant impact on the rise of liver somatic index, while lipid profile improved by decreasing the levels of TC, LDL-C, TC/HDL-C, AI, TG, and increasing HDL-C in the serum of rats (P<.05). Total plasma antioxidant capacity determined by ABTS, FRAP, and DPPH assays was increased. ALP in rat serum was higher in groups receiving cholesterol diets and kiwifruit. A decrease in fibrinogen as well as prolonged prothrombin time and a reduction of the MPO in serum were estimated. The smallest percentage of lesions in the aortic arch was in the ChGeneva, ChWeiki, and ChAnna. Similarly, the smallest fatty liver disease was recorded in the ChGeneva and ChAnna groups. The distribution of lipids in the liver from these groups had a character of "mosaic," in hardy/mini kiwifruit (Jumbo), Hayward, and Bidan was distributed uniformly. The longest villi were in ChWeiki, and significantly lower in ChHayward and ChBidan. The present results support our hypothesis that A. arguta showed better pro-health impacts in rats loaded with cholesterol than Hayward and Bidan kiwifruit, and, for the first time, the positive nutritional effects of supplemented A. arguta for hypercholesterolemia are noted.

Novel biomarkers for cardiovascular risk assessment: current status and future directions

Cardiovascular disease (CVD) is the leading cause of mortality in the modern world. Traditional risk algorithms may miss up to 20% of CVD events. Therefore, there is a need for new cardiac biomarkers. Many fields of research are dedicated to improving cardiac risk prediction, including genomics, transcriptomics and proteomics. To date, even the most promising biomarkers have only demonstrated modest associations and predictive ability. Few have undergone randomized control trials. A number of biomarkers are targets to new therapies aimed to reduce cardiovascular risk. Currently, some of the most promising risk prediction has been demonstrated with panels of multiple biomarkers. This article reviews the current state and future of proteomic biomarkers and aggregate biomarker panels.

"Normoalbuminuric" diabetic nephropathy: tubular damage and NGAL

The aim of this study was to demonstrate that neutrophil gelatinase-associated lipocalin (NGAL) increased before the onset of microalbuminuria in patients with type 1 diabetes mellitus (T1DM), representing an important biochemical parameter with high sensitivity and specificity to make a precocious diagnosis of "normoalbuminuric" diabetic nephropathy (DN). Serum NGAL (sNGAL) and urinary NGAL (uNGAL) levels were evaluated in a cohort of fifty patients affected by T1DM. They had no signs of clinical nephropathy. Thirty-five healthy subjects (HS) were recruited. sNGAL levels were significantly higher compared with those measured in HS [193.7 (103.2-405.4) vs. 46.4 (39.8-56.2) ng/ml; p < 0.0001], as were uNGAL levels [25.5 (14.2-40.2) vs. 6.5 (2.9-8.5) ng/ml; p < 0.0001]. sNGAL was found to be directly correlated with glycated hemoglobin. uNGAL also positively correlated with albuminuria, whereas an inverse correlation was found with uric acid. After multivariate analysis, significance was maintained for the correlation between uNGAL and microalbuminuria. In ROC analysis, sNGAL showed a good diagnostic profile such as uNGAL. NGAL increases in patients with T1DM, even before diagnosis of microalbuminuria representing an early biomarker of "normoalbuminuric" DN with a good sensitivity and specificity. NGAL measurement could be useful for the evaluation of early renal involvement in the course of diabetes.

Pro-inflammatory effects of the mushroom Agaricus blazei and its consequences on atherosclerosis development

PURPOSE

Extracts of the mushroom Agaricus blazei (A. blazei) have been described as possessing immunomodulatory and potentially cancer-protective activities. However, these effects of A. blazei as a functional food have not been fully investigated in vivo.

METHODS

Using apolipoprotein E-deficient (ApoE(-/-)) mice, an experimental model of atherosclerosis, we evaluated the effects of 6 or 12 weeks of A. blazei supplementation on the activation of immune cells in the spleen and blood and on the development of atherosclerosis.

RESULTS

Food intake, weight gain, blood lipid profile, and glycemia were similar between the groups. To evaluate leukocyte homing and activation, mice were injected with (99m)Tc-radiolabeled leukocytes, which showed enhanced leukocyte migration to the spleen and heart of A. blazei-supplemented animals. Analysis of the spleen showed higher levels of activation of neutrophils, NKT cells, and monocytes as well as increased production of TNF-α and IFN-γ. Circulating NKT cells and monocytes were also more activated in the supplemented group. Atherosclerotic lesion areas were larger in the aorta of supplemented mice and exhibited increased numbers of macrophages and neutrophils and a thinner fibrous cap. A. blazei-induced transcriptional upregulation of molecules linked to macrophage activation (CD36, TLR4), neutrophil chemotaxy (CXCL1), leukocyte adhesion (VCAM-1), and plaque vulnerability (MMP9) were seen after 12 weeks of supplementation.

CONCLUSIONS

This is the first in vivo study showing that the immunostimulatory effect of A. blazei has proatherogenic repercussions. A. blazei enhances local and systemic inflammation, upregulating pro-inflammatory molecules, and enhancing leukocyte homing to atherosclerosis sites without affecting the lipoprotein profile.

The -omics era: proteomics and lipidomics in vascular research

A main limitation of the current approaches to atherosclerosis research is the focus on the investigation of individual factors, which are presumed to be involved in the pathophysiology and whose biological functions are, at least in part, understood. These molecules are investigated extensively while others are not studied at all. In comparison to our detailed knowledge about the role of inflammation in atherosclerosis, little is known about extracellular matrix remodelling and the retention of individual lipid species rather than lipid classes in early and advanced atherosclerotic lesions. The recent development of mass spectrometry-based methods and advanced analytical tools are transforming our ability to profile extracellular proteins and lipid species in animal models and clinical specimen with the goal of illuminating pathological processes and discovering new biomarkers.

From kidney to cardiovascular diseases: NGAL as a biomarker beyond the confines of nephrology

Neutrophil gelatinase-associated lipocalin (NGAL), a small 25 kDa stress-protein released from injured tubular cells after various damaging stimuli, is already known by nephrologists as one of the most promising biomarkers of incoming Acute Kidney Injury. Moreover, recent studies seem to suggest a potential involvement of this factor also in the genesis and progression of chronic kidney diseases. This brief review explores the new interesting involvement of NGAL in the experimental and clinical field of cardiovascular diseases, such as the pathogenesis and clinical manifestations of atherosclerosis, acute myocardial infarction and heart failure. It does not seem difficult that, in the next future, NGAL may become a new missing link between the kidney and the cardiovascular system.

Oxidized low-density lipoprotein

Oxidized low-density lipoprotein (Ox-LDL) has been studied for over 25 years. Numerous pro- and anti-atherogenic properties have been attributed to Ox-LDL. Yet, Ox-LDL has neither been defined nor characterized, as its components and composition change depending on its source, method of preparation, storage, and use. It contains unoxidized and oxidized fatty acid derivatives both in the ester and free forms, their decomposition products, cholesterol and its oxidized products, proteins with oxidized amino acids and cross-links, and polypeptides with varying extents of covalent modification with lipid oxidation products, and many others. It seems to exist in vivo in some form not yet fully characterized. Until its pathophysiological significance, and how it is generated in vivo are determined, the nature of its true identity will be only of classical interest. In this review, its components, their biological actions and methods of preparation will be discussed.

Darapladib and atherosclerotic plaque: should lipoprotein-associated phospholipase A2 be a therapeutic target?

There is great interest in developing a reliable measure of atherosclerotic disease activity that can serve as an index of response to antiatherosclerotic therapies. The epidemiologic relationship between lipid measures, most notably low-density lipoprotein cholesterol (LDL-C), and binary cardiovascular events has been confirmed in treatment trials reliably demonstrating a reduction in LDL-C translating into improved cardiovascular outcomes. Lipoprotein-associated phospholipase A2 (LpPLA2) is part of a family of lipases involved in the modification of lipids within the atheroma and may be a complimentary therapeutic target to the reduction of LDL-C in patients with advanced atherosclerosis. Darapladib is an orally available, specific inhibitor of LpPLA2 activity and has been shown to reduce lysophosphatidylcholine content and expression of multiple genes associated with macrophage and T-lymphocyte functioning, with considerable decrease in plaque and necrotic core area. Thus, this agent holds the hope of being a bona fide antiatherosclerotic therapy that can be gauged through blood measurement of LpPLA2 activity.

Biomarkers of atherosclerosis: clinical applications

Current cardiovascular risk prediction models incorporate traditional risk factors to estimate 10-year cardiovascular risk. Numerous blood-based biomarkers have been identified that are associated with increased cardiovascular risk after adjusting for traditional risk factors. Many of these biomarkers, alone or in combination, have been incorporated into risk prediction models to determine whether their addition increases the model's predictive ability. We review the recently published literature on blood-based biomarkers and examine whether incorporating these markers may improve clinical decision making.

Effects of antioxidant-rich foods on vascular reactivity: review of the clinical evidence

The foods and nutrients discussed in this paper are components of dietary patterns that have been associated with lower cardiovascular disease risk. The focus of this review is on the effects of antioxidant foods on vascular health and discussion of their potential mechanisms of action. The foods reviewed include fruits and vegetables, red grapes and red wine, tea, cocoa/chocolate, and olive oil. The primary challenge in studying the cardioprotective components of a dietary pattern is in identifying mechanism(s) of action as well as the bioactive nutrients responsible. In selecting papers for this review, we focused on studies of whole foods and beverages that met the following criteria: 1) they are commonly consumed in typical diets, 2) they appear to have direct antioxidant effects, and 3) they have demonstrated effects on endothelial function in several human studies. The evidence presented herein suggests that dietary consumption of fruits and vegetables, red grapes and red wine, tea, chocolate, and olive oil may improve vascular reactivity, in part, by attenuating the adverse effects of oxidation on endothelial function. Additional research is needed to better understand the mechanism(s) by which antioxidant-rich foods and beverages favorably affect endothelial function and the extent to which this reflects direct antioxidant effects.