The prognostic value of nitrotyrosine levels in coronary heart disease: long-term evaluation in the Acute Coronary Syndrome Registry Strategy (ERICO study)

Glycyrrhizic Acid Inhibits High-Mobility Group Box-1 and Homocysteine-Induced Vascular Dysfunction

Hyperhomocysteinemia (HHcy) worsens cardiovascular outcomes by impairing vascular function and promoting chronic inflammation via release of danger-associated molecular patterns, such as high-mobility group box-1 (HMGB-1). Elevated levels of HMGB-1 have recently been reported in patients with HHcy. Therefore, targeting HMGB-1 may be a potential therapy to improve HHcy-induced cardiovascular pathologies. This study aimed to further elucidate HMGB-1's role during acute HHcy and HHcy-induced atherogenesis and to determine if inhibiting HMGB-1 with glycyrrhizic acid (Glyz) improved vascular function. Male New Zealand White rabbits (n = 25) were placed on either a standard control chow (CD; n = 15) or atherogenic diet (AD; n = 10) for 4 weeks. Rabbit serum and Krebs taken from organ bath studies were collected to quantify HMGB-1 levels. Isometric tension analysis was performed on abdominal aorta (AA) rings from CD and AD rabbits. Rings were incubated with homocysteine (Hcy) [3 mM] for 60 min to induce acute HHcy or rhHMGB-1 [100 nM]. Vascular function was assessed by relaxation to cumulative doses of acetylcholine. Markers of vascular dysfunction and inflammation were quantified in the endothelium, media, and adventitia of AA rings. HMGB-1 was significantly upregulated in serum (p < 0.0001) and Krebs (p < 0.0001) after Hcy exposure or an AD. Incubation with Hcy (p < 0.0001) or rhHMGB-1 (p < 0.0001) and an AD (p < 0.0001) significantly reduced relaxation to acetylcholine, which was markedly improved by Glyz. HMGB-1 expression was elevated (p < 0.0001) after Hcy exposure and AD (p < 0.0001) and was normalized after Glyz treatment. Moreover, markers of vascular function, cell stress and inflammation were also reduced after Glyz. These results demonstrate that HMGB-1 has a central role during HHcy-induced vascular dysfunction and inhibiting it with Glyz could be a potential treatment option for cardiovascular diseases.

The Impact of Exercise on Redox Equilibrium in Cardiovascular Diseases

Cardiovascular diseases constitute the most important public health problem in the world. They are characterized by inflammation and oxidative stress in the heart and blood. Physical activity is recognized as one of the best ways to prevent these diseases, and it has already been applied in treatment. Physical exercise, both aerobic and anaerobic and single and multiple, is linked to the oxidant–antioxidant imbalance; however, this leads to positive adaptive changes in, among others, the increase in antioxidant capacity. The goal of the paper was to discuss the issue of redox equilibrium in the human organism in the course of cardiovascular diseases to systemize updated knowledge in the context of exercise impacts on the organism. Antioxidant supplementation is also an important issue since antioxidant supplements still have great potential regarding their use as drugs in these diseases.

Nitrotyrosine, Nitrated Lipoproteins, and Cardiovascular Dysfunction in Patients with Type 2 Diabetes: What Do We Know and What Remains to Be Explained?

Diabetes mellitus (DM) is a strong risk factor for the development of cardiovascular diseases (CVDs), which are the most important cause of morbidity and mortality in the population of patients living with DM. DM is associated with lipid metabolism disorders characterized by a decrease in the high-density lipoprotein blood concentration, an increase in the triglyceride blood concentration, and the presence of modified lipoproteins not routinely measured in clinical practice. Nitrated lipoproteins are produced by the nitration of the tyrosyl residues of apolipoproteins by myeloperoxidase. There is some evidence from the research conducted showing that nitrated lipoproteins may play a role in the development of cardiovascular dysfunction, but this issue requires further investigation. It was found that the nitration of HDL particles was associated with a decrease in caspase-3 and paraoxonase-1 activity, as well as a decrease in the activity of cholesterol transport via ABCA1, which reduces the protective effect of HDL particles on the cardiovascular system. Less information has been collected about the role of nitrated LDL particles. Thus far, much more information has been obtained on the relationship of nitrotyrosine expression with the presence of cardiovascular risk factors and the development of cardiovascular dysfunction. The purpose of this paper is to provide an extensive review of the literature and to present the most important information on the current state of knowledge on the association between nitrotyrosine and nitrated lipoproteins with dysfunction of the cardiovascular system, especially in patients living with DM. Moreover, directions for future research in this area were discussed.

Altered amino acid metabolism between coronary heart disease patients with and without type 2 diabetes by quantitative 1H NMR based metabolomics

Coronary heart disease (CHD) is a multifactorial disease associated with complicated altered metabolic pathways, especially when it occurs with type 2 diabetes (T2D). Identification of metabolic changes could provide further understanding of the underlying pathological link between with CHD and T2D. In this study, 61 controls, 30 consecutive patients with only T2D, 188 with confirmed CHD among which 50 also having T2D were enrolled. Quantitative ¹H nuclear magnetic resonance (¹H NMR) based metabonomic approach was used to obtain the plasma metabolic profiles of the study samples. Multivariate principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA) were used to evaluate the differences of metabolites. Compared with controls, there were significant differences in CHD patient with T2D groups including BCAAs (isoleucine, leucine, and valine) and phenylalanine by using quantitative metabolomic profiling (all p < 0.05). With OPLS-DA, the results showed that, compared to CHD patients without T2D, there had higher levels of metabolites for leucine, valine, fumarate, tyrosine, and phenylalanine in the plasma of CHD patients with T2D. Moreover, the CHD patients with T2D showed modified phenylalanine, tyrosine and tryptophan biosynthesis, valine, leucine and isoleucine biosynthesis and degradation compared with CHD patients without T2D. By ¹H NMR based quantitative metabolomic method, our findings suggest that T2D has important effects on BCAAs and AAAs metabolism in CHD patients indicating altered cardiac energy metabolism and activated signaling pathway could be potential targets for therapy in CHD disease combined with T2D.

Protein oxidation - Formation mechanisms, detection and relevance as biomarkers in human diseases

Generation of reactive oxygen species and related oxidants is an inevitable consequence of life. Proteins are major targets for oxidation reactions, because of their rapid reaction rates with oxidants and their high abundance in cells, extracellular tissues, and body fluids. Additionally, oxidative stress is able to degrade lipids and carbohydrates to highly reactive intermediates, which eventually attack proteins at various functional sites. Consequently, a wide variety of distinct posttranslational protein modifications is formed by protein oxidation, glycoxidation, and lipoxidation. Reversible modifications are relevant in physiological processes and constitute signaling mechanisms ("redox signaling"), while non-reversible modifications may contribute to pathological situations and several diseases. A rising number of publications provide evidence for their involvement in the onset and progression of diseases as well as aging processes. Certain protein oxidation products are chemically stable and formed in large quantity, which makes them promising candidates to become biomarkers of oxidative damage. Moreover, progress in the development of detection and quantification methods facilitates analysis time and effort and contributes to their future applicability in clinical routine. The present review outlines the most important classes and selected examples of oxidative protein modifications, elucidates the chemistry beyond their formation and discusses available methods for detection and analysis. Furthermore, the relevance and potential of protein modifications as biomarkers in the context of disease and aging is summarized.

Redox-related biomarkers in human cardiovascular disease - classical footprints and beyond

Global epidemiological studies show that chronic non-communicable diseases such as atherosclerosis and metabolic disorders represent the leading cause of premature mortality and morbidity. Cardiovascular disease such as ischemic heart disease is a major contributor to the global burden of disease and the socioeconomic health costs. Clinical and epidemiological data show an association of typical oxidative stress markers such as lipid peroxidation products, 3-nitrotyrosine or oxidized DNA/RNA bases with all major cardiovascular diseases. This supports the concept that the formation of reactive oxygen and nitrogen species by various sources (NADPH oxidases, xanthine oxidase and mitochondrial respiratory chain) represents a hallmark of the leading cardiovascular comorbidities such as hyperlipidemia, hypertension and diabetes. These reactive oxygen and nitrogen species can lead to oxidative damage but also adverse redox signaling at the level of kinases, calcium handling, inflammation, epigenetic control, circadian clock and proteasomal system. The in vivo footprints of these adverse processes (redox biomarkers) are discussed in the present review with focus on their clinical relevance, whereas the details of their mechanisms of formation and technical aspects of their detection are only briefly mentioned. The major categories of redox biomarkers are summarized and explained on the basis of suitable examples. Also the potential prognostic value of redox biomarkers is critically discussed to understand what kind of information they can provide but also what they cannot achieve.

Peroxiredoxin2 (Prdx2) Reduces Oxidative Stress and Apoptosis of Myocardial Cells Induced by Acute Myocardial Infarction by Inhibiting the TLR4/Nuclear Factor kappa B (NF-κB) Signaling Pathway

BACKGROUND Peroxiredoxin2 (Prdx2) is an endogenous peroxidase and has been found to reduce the oxidative burden in cells and thereby reduce cell damage and apoptosis. Therefore, the purpose of this study was to investigate the effect of Prdx2 on the oxidative level and apoptosis of myocardial cells after acute myocardial infarction (AMI). MATERIAL AND METHODS We constructed an AMI model for Sprague-Dawley rats by ligating the left anterior descending coronary artery. We determined the effect of Prdx2 on AMI by detecting changes in Prdx2 in myocardial tissue via western blot and qRT-PCR. In addition, we used recombinant Prdx2 protein to treat rats and detect changes in oxidative stress and apoptosis in rat myocardial tissue to verify the protective effect of Prdx2 on the rat heart. RESULTS The protein and mRNA expression of Prdx2 in myocardial tissue of rats in the AMI group was significantly lower than that in the control group. The oxidative and apoptotic levels of myocardial tissue in Prdx2-administered rats were significantly improved compared to the non-administered group, which was manifested by a decrease in reactive oxygen species (ROS) levels and a decrease in the expression of the caspase family. In addition, Prdx2 also inhibited p65 phosphorylation in myocardial tissues and inhibited TLR4/NF-kappaB signaling pathway activity. CONCLUSIONS The expression of Prdx2 was decreased in myocardial tissue after AMI. Prdx2 can reduce apoptosis and ROS caused by AMI by inhibiting the TLR4/NF-kB signaling pathway, thereby reducing myocardial injury caused by AMI.