Evaluation of the resistance of blood plasma to oxidative stress by oxidizability of proteins and lipids during metal-catalyzed oxidation

A new approach for the evaluation of oxidizability of proteins and lipids in the same sample of blood plasma was proposed. We tested a method for evaluation of metal-catalyzed oxidation of fibrinogen by the formation of bityrosine cross-links during oxidation detected by the increase in fluorescence at 415 nm. A correlation was revealed between parameters of oxidizability estimated by this marker and carbonyl derivatives (dinitrophenylhydrazine method). Oxidizability of total proteins from whole plasma was compared with oxidizability of plasma lipids (marker malonic dialdehyde). Study of these parameters in patients with coronary heart disease showed that the proposed experimental approach allows us to divide the sample into several subgroups differing in the resistance to oxidative stress. These data can be used for diagnostic and prognostic purposes. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 9, pp. 268–272, September, 2006     

Oxidative Stress in Atherosclerosis and Diabetes

We measured the content of lipid peroxides in plasma LDL from patients with chronic CHD not accompanied by hypercholesterolemia; CHD and hypercholesterolemia; type 2 diabetes mellitus and decompensation of carbohydrate metabolism; and CHD, circulatory insufficiency, and type 2 diabetes mellitus (without hypercholesterolemia). The content of lipid peroxides in LDL isolated from blood plasma by differential ultracentrifugation in a density gradient was estimated by a highly specific method with modifications (reagent Fe²⁺ xylene orange and triphenylphosphine as a reducing agent for organic peroxides). The content of lipid peroxides in LDL from patients was much higher than in controls (patients without coronary heart disease and diabetes). Hypercholesterolemia and diabetes can be considered as factors promoting LDL oxidation in vivo. Our results suggest that stimulation of lipid peroxidation in low-density lipoproteins during hypercholesterolemia and diabetes is associated with strong autooxidation of cholesterol and glucose during oxidative and carbonyl (aldehyde) stress, respectively. These data illustrate a possible mechanism of the progression of atherosclerosis in patients with diabetes mellitus. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 7, pp. 48–51, July, 2005     

Effect of oxidized LDL on hemolytic resistance of erythrocyte

Using the method of peroxide-induced chemiluminescence we showed that incubation of the whole blood with oxidized LDL or oxidized blood plasma increased plasma hemoglobin concentration, which linearly depended on the degree of LDL oxidation. Similar effects were observed in erythrocyte suspension. Hemolytic activity of oxidized plasma 3-4-fold surpassed that of LDL isolated by ultracentrifugation. LDL capacity to oxidation in the presence of Cu²⁺ increased by 50% and osmotic hemolysis of erythrocytes increased by 53% in coronary patients in comparison with healthy donors. These results indicate that oxidized LDL induce erythrocyte hemolysis.     

Dynamics of formation of primary and secondary lipid peroxidation products upon copper-dependent oxidation of low-density lipoproteins isolated from blood serum of patients with ischemic heart disease

The kinetics of copper-induced oxidation of lipids in serum low-density lipoproteins from healthy subjects and patients with ischemic heart disease and documented coronary atherosclerosis is studied. After a 4-h incubation with 40 μM CuSO₄, the oxidizability of patients' lipoproteins is higher, judging from the contents of diene conjugates and oxidation products reacting with thiobarbituric acid. Intergroup differences in the kinetics of the diene conjugate formation are revealed. Statistical analysis shows that in all studied individuals there is no relationship between the oxidizability of low-density lipoproteins and the cholesterol content in lipoproteins and serum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 32–36, July, 1996     

Trimetazidine as Indirect Antioxidant

One-month therapy with trimetazidine sharply decreased the content of free radical oxidation products, lipid peroxides and malonic dialdehyde, in atherogenic low-density lipoproteins in patients with coronary heart disease. Activity of glutathione peroxidase utilizing lipid peroxides in the plasma markedly increased during trimetazidine therapy. The data suggest that trimetazidine not directly interacting with free radicals attenuates the adverse effects of intensive free radical oxidation in coronary heart disease. This effect is mediated via activation of antioxidant enzymes, which diminishes negative consequences of ischemia.     

Trimetazidine as indirect antioxidant

One-month therapy with trimetazidine sharply decreased the content of free radical oxidation products, lipid peroxides and malonic dialdehyde, in atherogenic low-density lipoproteins in patients with coronary heart disease. Activity of glutathione peroxidase utilizing lipid peroxides in the plasma markedly increased during trimetazidine therapy. The data suggest that trimetazidine not directly interacting with free radicals attenuates the adverse effects of intensive free radical oxidation in coronary heart disease. This effect is mediated via activation of antioxidant enzymes, which diminishes negative consequences of ischemia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 10, pp. 395–398, October, 2000     

Antioxidant probucol as an effective scavenger of lipid radicals in low density lipoproteinsin vivo andin vitro

Probucol in concentrations of 10–15 μM effectively inhibits Cu²⁺-induced free radical oxidation of native low density lipoproteins and in concentration of 100 μM it inhibits lipoperoxide formation. The mean plasma concentration of probucol in patients receiving 250 mg of this drug is 25 μM. Both 250 and 1000 mg probucol daily during 3–6 month block the oxidation of isolated low density lipoproteins. Electron paramagnetic resonance spectrometry data showed that probucol incorporatedin vivo into lipoprotein particles interacts with lipid radicals yielding long-lived phenoxyradicals. Probucol can be used in complex therapy of atherosclerosis as an antioxidant drug and its dose required for lipoprotein protection against atherogenic modification can be decreased to 250 mg/day. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 8, pp. 186–189, August, 1999     

Plasma fibrinogen — a major coronary risk factor

The role of plasma fibrinogen as a potential indicator of susceptibility to heart attacks was studied in a sample of 297 men aged 40-69 years at entry who were initially free from overt coronary heart disease. During a mean observation period of 7.3 years (range 0.1-16.1) new heart attacks occurred in 40 men. There was a significant positive correlation between initial plasma fibrinogen levels and the subsequent incidence of heart attacks. In men with high cholesterol or high systolic blood pressure levels the incidence of heart attacks was respectively six times and 12 times greater in those with high plasma fibrinogen levels than in those with low fibrinogen levels. In multivariate models plasma fibrinogen was a highly significant and independent explanatory variable, at least as important as serum cholesterol, blood pressure or cigarette smoking. These results suggest that high plasma fibrinogen levels are an important coronary risk factor and should be included in profiles used to identify those at high risk of heart attacks.     

Increases in lipids and immune cells in response to exercise and mental stress in patients with suspected coronary artery disease: effects of adjustment for shifts in plasma volume

This study examined the role of shifts in plasma volume on lipid and immune reactions to stress. Lipid, immune, rheological, and cardiovascular reactions to exercise and mental stress in 51 patients with suspected coronary artery disease were determined. Blood pressure and heart rate were measured during and blood samples taken at the end of each rest and task. Lipids (total cholesterol, triglycerides, HDL, LDL) and immune cells (lymphocytes, monocytes, granulocytes) increased with exercise, whereas cholesterol, LDL, and lymphocytes increased with mental stress. Plasma volume decreased by 1 and 5% following mental and exercise stress, respectively. The task-induced increases in lipids were no longer statistically significant following adjustment for changes in plasma volume, whereas the increases in immune cell numbers survived such correction. This study provides evidence that, in coronary artery disease patients, exercise and mental stress-induced increases in lipids but not immune cells can be largely accounted for by shifts in plasma volume.     

Synthetic peptide fragment (65�C76) of monocyte chemotactic protein-1 (MCP-1) inhibits MCP-1 binding to heparin and possesses anti-inflammatory activity in stable angina patients after coronary stenting

Objective and design

The peptide from C-terminal domain of MCP-1 (Ingramon) has been shown to inhibit monocyte migration and possess anti-inflammatory activity in animal models of inflammation and post-angioplasty restenosis. Here, we investigate the effect of Ingramon treatment on blood levels of acute-phase reactants and chemokines in patients after coronary stenting and the mechanisms of Ingramon anti-inflammatory activity.

Subjects

Eighty-seven patients with ischemic heart disease (IHD) who faced the necessity of coronary angiography (CA) were enrolled. In 67 patients, one-stage coronary stenting was performed; 33 of them were treated with Ingramon in addition to standard therapy. Twenty patients underwent CA only.

Methods

High-sensitivity C-reactive protein (hsCRP) and fibrinogen blood levels were detected routinely. The chemokine concentration in plasma was measured by enzyme-linked immunosorbent assay (ELISA) or cytometric bead array-based immunoassay. Intracellular Ca²⁺ levels and cell surface integrin exposure were assayed by flow cytometry. MCP-1 dimerization was studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). MCP-1?Cheparin binding was assessed with a biosensor and ELISA.

Results and conclusions

Ingramon treatment was accompanied by less pronounced elevation of hsCRP and fibrinogen levels and decreased MCP-1 concentration in plasma in patients after coronary stenting. Ingramon had no effect on MCP-1 interaction with cell receptors or MCP-1 dimerization, but inhibited MCP-1 binding to heparin. The anti-inflammatory activity of the peptide may be mediated by an impaired chemokine interaction with glycosaminoglycans.     

Oxidation of Plasma Low-Density Lipoproteins from Coronary Patients with Various Forms of Hypercholesterolemia

The duration of lag-phase of copper-induced free-radical oxidation of atherogenic LDL isolated from the plasma of coronary patients without hypercholesterolemia virtually does not differ from that of normal human LDL. On the other hand, lag-phase of plasma LDL oxidation was minimal in coronary patients with primary hypercholesterolemia without familial history and especially in patients with familial hypercholesterolemia. This can be attributed to sharply decreased content of natural lipid antioxidants in LDL of patients with familial hypercholesterolemia. However, therapy with natural antioxidant vitamin E did not modulate oxidizability of these LDL. By contrast, therapy with -hydroxy--methylglutaryl-coenzyme A reductase inhibitor suppressing biosynthesis of ubiphenol Q induced sharp accumulation of lipoperoxides in LDL in vivo. These data suggest that reduced form of ubiquinone Q is the main antioxidant protecting LDL from free-radical oxidation.     

Hemostasis and cardiovascular risk. The British and European experience.

There is evidence that increased reactivity of blood plasma to thrombogenic surfaces (hypercoagulability) may contribute to the risk of thrombotic occlusion of a coronary artery in coronary heart disease. The Northwick Park Heart Study found raised levels of factor VII coagulant (VIIc) activity and fibrinogen in men at high risk of a coronary event. Several other European studies have confirmed the latter finding, but the Northwick Park Heart Study is the only study to report formally on VIIc to date. Plasma VIIc is increased in the presence of hyperlipidemia and on a high fat diet, and falls with lipid-lowering therapy and a reduction in fat intake. Fibrinogen concentration is raised in smokers and decreases when the habit is given up. Thus, these markers of thrombogenic risk are readily controlled by standard preventive measures against coronary heart disease. Unresolved issues include: (1) whether the distinctive features of the Northwick Park VII bioassay improve the value of VIIc as a predictor of coronary heart disease; (2) the separate extent to which activation of factor VII and increases in factor VII concentration account for the raised VIIc in hyperlipidemia; (3) the basis of the raised fibrinogen in men at high coronary heart disease risk, even among nonsmokers; and (4) the usefulness of plasma levels of activation peptides of factors IX, X, and prothrombin as markers of thrombogenic risk.     

Increased levels of low-density lipoprotein oxidation in patients with familial hypercholesterolemia and in end-stage renal disease patients on hemodialysis

Patients with familial hypercholesterolemia (FH) and patients with end-stage renal disease (ESRD) undergoing dialysis suffer from accelerated atherosclerosis. Oxidation of low-density lipoprotein (LDL) cholesterol is crucial in atherogenesis. In the present study, we determined the LDL oxidation level and oxidizability of isolated LDL of 11 male patients with FH, 15 male ESRD patients on hemodialysis, and 15 age-matched male normolipidemic healthy controls. FH patients were without lipid-lowering medication for at least 4 weeks and were reassessed after 2 years of cholesterol-lowering therapy (statins). LDL oxidation level was measured by ELISA using monoclonal antibody 4E6 to oxidized LDL (oxLDL) as the capture antibody and anti-human apoB antibody for detection; results were expressed as percentage oxLDL. In FH patients and in ESRD patients on hemodialysis, both groups having a higher percentage of cardiovascular disease, mean plasma LDL oxidation levels were significantly elevated compared with controls (4.9 +/- 1.3; 3.7 +/- 2.0; 1.7 +/- 0.6%, respectively). Within each group of subjects, LDL oxidation level was not associated with history of cardiovascular disease. Furthermore, in neither group was a significant correlation found between plasma concentration of LDL cholesterol and LDL oxidation level. After cholesterol-lowering therapy, LDL oxidation level in FH patients had not changed significantly and remained elevated compared with controls, despite a reduction of LDL cholesterol by 55% on average. Also, absolute plasma oxLDL concentrations, obtained by multiplying LDL oxidation level with plasma LDL cholesterol concentration, were significantly higher in FH patients before and after cholesterol-lowering therapy and in ESRD patients on hemodialysis than in controls (489 +/- 145; 189 +/- 122; 100 +/- 65; and 59 +/- 27 micro moles/L, respectively). No correlation was found between plasma oxLDL concentration and parameters of LDL oxidizability, LDL fatty acids, and LDL alpha-tocopherol content. We conclude that cholesterol-lowering therapy does not normalize elevated LDL oxidation levels in FH patients and elevated LDL oxidation level in FH and in ESRD might mirror atherosclerosis.     

冠状动脉病变程度与血浆B型利钠肽对冠心病的影响因素

目的 探讨冠心病患者冠状动脉病变程度与血浆B型利钠肽的关系。方法 选择我院2017年1月~8月住院的冠心病患者54例为A组,同时选择冠脉血管无狭窄的患者26例作为B组,收集所有研究对象的年龄、性别、血糖、血脂、血压、血浆脑钠肽（BNP）浓度、冠状动脉的病变部位及程度等临床资料,观察不同程度冠状动脉病变患者的血浆BNP水平。结果 血浆BNP水平A组较B组升高,统计学意义显著（P＜0.001）。Logistic回归分析显示,年龄、BNP水平、舒张压是冠状动脉狭窄的独立危险因素。在A1、A2及A3组中随着Gensini评分增加,血浆BNP水平逐渐升高,Gensini评分与血浆BNP水平呈明显的正相关（r=0.594,P＜0.05）。结论 血浆BNP参与了冠状动脉狭窄的病理生理过程,是冠状动脉病变的独立危险因素之一;血浆BNP的水平能一定程度上的反映冠脉病变程度。     

冠心病血浆和血清粘度与有关生物大分子含量的探讨

本文对51例冠心病血浆和血清粘度与纤维蛋白原、胆固醇、甘油三酯、球蛋白等生物物质含量的关系进行观察,与正常50例对照。结果示:非心梗组血浆粘度,全血还原粘度等均呈显著差异(P<0.05)。心梗组与非心梗组比全血粘度、血清粘度、纤维蛋白原、IgA、IgM也有显著差异(P<0.05)。我们认为,冠心病患者血液流变学及血液大分子含量明显异常,这在冠心病的病因学和治疗学上均有重要意义。     

Chemiluminescence study of the contents of the products of Cu2+-induced lipid peroxidation in different fractions of human blood lipoproteins

It is demonstrated that the content of the primary products of lipid peroxidation reaches the maximum after about 1-h incubation with Cu²⁺ and then declines. At a Cu²⁺ concentration of about 10–15 μM, the content of lipid peroxidation products is maximal; it does not rise with a further increase in the Cu²⁺ concentration. Comparison of the kinetics of lipid peroxidation in different lipoprotein fractions shows that low density lipoproteins are much more strongly oxidized than high density lipoproteins. A strong positive correlation between the amplitude of the chemiluminescence burst and the diene conjugate content is established in 79 independent measurements. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 2, pp. 144–148, February, 1995     

The effect of exercise on atherosclerosis in the coronary artery and abdominal aorta of mature female swine

Summary This study investigated the effects of chronic exercise on atherosclerosis in the aorta and coronary artery in mature female swine. Preceding and during the exercise training period these animals were fed high fat, (soybean or corn oil) cholesterol-free diets. Sixteen swine were paired according to breed, body weight, and diet. Eight swine were a non-exercise control group while the remaining eight were an experimental group and exercised 4 days per week for 4 months. The exercise training program initially consisted of running at 5.6 km·h⁻¹, zero gradient, for 15 min with increments of 1 min of running time every 2 weeks. The amount of atherosclerosis in the coronary artery and abdominal aorta was determined directly. Plasma lipids, body weight, body potassium, and percent fat were recorded at three intervals during the training program. Four months of exercise had no significant effect on plasma cholesterol, phospholipids, total lipids or triglycerides, although there was a significant effect of test periods on cholesterol. Diet was found to have no influence on plasma lipids. The exercise group did not have larger heart weights, ratio of heart weight to body weight or ratio of heart weight to fat-free body weight. The percent lipid in the lesion area and the lesion surface area of the abdominal aorta was not significantly different between the two groups. The amount of lipid obtained from the intima-media of the coronary artery and the lesion area involvement was not significantly different between the exercise group and the non-exercise group. It is concluded that 4 months of exercise had no effect on plasma lipids, body potassium, body weight, or coronary and aortic atherosclerosis.     

Antihypertensive Therapie und Fettstoffwechsel

Summary Hypertension, hyperlipidaemia and cigarette smoking are major risk factors in coronary heart disease. Since many antihypertensive drugs alter plasma lipid levels it is a subject of current discussion that these agents may increase associated coronary risk and therefore offset the beneficial effects of lowering blood pressure. The purpose of this paper is to review clinical and experimental data in the literature on the influence of antihypertensive drugs on lipid metabolism. The thiazides hydrochlorothiazide and chlorthalidone cause an elevation of plasma triglycerides and very low density lipoprotein (VLDL) but have little effect on total cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL). The unspecific beta-blockers, e.g. propranolol, do not affect total cholesterol and LDL but increase total triglycerides and VLDL and decrease HDL. The changes of plasma lipids and lipoproteins caused by cardio-selective beta-blockers, e.g. atenolol and metoprolol, and unspecific beta-blockers with intrinsic sympathomimetic activity (ISA), e.g. oxprenolol and pindolol, appear to be qualitatively similar but less pronounced. The alpha₁-blocker prazosin reduces total triglycerides and slightly lowers total cholesterol. The concentration of VLDL plus LDL decreases while HDL may increase. Only very few studies have been reported on the effects of other antihypertensive drugs, e.g. clonidine, hydralazine, on plasma lipids. Several experimental studies reveal that antihypertensive agents exert direct effects on triglyceride and cholesterol metabolism. Although the pathophysiological mechanisms and the significance of the alterations of lipid metabolism induced by antihypertensive drugs are not yet clear, the following guidelines for the clinical use of these agents are recommended: (1) before initiating drug treatment in hypertensive patients, blood lipid levels should be measured to exclude a preexisting hyperlipidaemia, (2) during long-term therapy with antihypertensive agents, lipoprotein fractions should be controlled in order to reconsider the therapeutic regime if major alterations of blood lipid levels are observed.

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Abkürzungen VLDL Very Low Density Lipoprotein - LDL Low Density Lipoprotein - HDL High Density Lipoprotein     

Changes in serum lipids, plasma fibrinogen and other haemostatic parameters induced by ciprofibrate action in hyperlipidemic patients with and without coronary artery disease

The effects of drugs with hypolipidemic properties in the prevention of the atherothrombotic vascular disease, go further than reducing serum lipids, suggesting that there are other nonlipid-related mechanisms involved; the maintenance of appropriate haemostatic balance being one of them. The objective of this investigation was a drug intervention with ciprofibrat in hyperlipidemic people with high level of plasmatic fibrinogen with the purpose of knowing the effects of the drug over these risk factors and other haemostatic parameters. Forty people, both sexes, 20 of them apparently healthy and the other 20 with clinical and angiographic evidence of coronary artery disease, were randomized to receive 100 mg of ciprofibrat or placebo during an average of 56 weeks. All of them had a clinical exam, EKG and stress test. Laboratory exams included lipid profile, plasma fibrinogen (Fg), VII factor, vonWillebrand factor, protein C (PC) and the tissue plasminogen activator with samples taken every 8 weeks. The Ciprofibrat group showed significant changes of lipids: cholesterol -23%, triglycerides -31%, high-density lipoprotein (HDLc) +24% and very low-density lipoprotein -23%, except low-density lipoprotein -24%. The haemostatic parameters in 40 weeks showed that Fg decreased 21% (p = 0.001), decreasing to 9% at the end of the follow-up. In the placebo group the HDLc showed a 10% increase (p = 0.02), PC reduced to 20% (p = 0.01) and Fg kept blood levels close to basal line, descending 10% at the end of the follow-up. In this study, the use of ciprofibrat in patients with high risk of developing atherothrombotic events, showed efficiency and security in handling hyperlipidemia, such as keeping and appropriate haemostatic balance.     

血液中叶酸、维生素B12水平与冠状动脉病变的关系及其机理探讨

为探讨血液中叶酸、维生素B12(VB12)水平与冠状动脉病变的关系及其机理,测定了94例冠心病(CHD)患者的全血叶酸、血浆叶酸和VB12水平,与39名对照者进行对比,并对叶酸、VB12水平与发生病变的冠脉支数间的关系进行研究;随机抽取57例受试者进行血浆同型半胱氨酸(Hcy)与血脂测定,探讨叶酸、VB12水平与血浆Hcy和血脂的相关性。结果显示,CHD患者的全血叶酸、血浆叶酸和VB12水平均显著低于对照组(P<0.05),不同冠脉病变支数的患者叶酸和VB12水平无显著性差异,全血叶酸、血浆叶酸和VB12水平与Hcy呈负相关,与血脂水平无关,提示血液中较低的叶酸、VB12水平与CHD有关,叶酸与VB12水平降低导致的Hcy增高可能是CHD的一个独立的危险因素。