Alpha-tocopherol supplementation decreases electronegative low-density lipoprotein concentration [LDL(-)] in haemodialysis patients

Background. Oxidative stress is a significant contributor to cardiovascular diseases (CVD) in haemodialysis (HD) patients, predisposing to the generation of oxidized low-density lipoprotein (oxLDL) or electronegatively charged LDL subfraction. Antioxidant therapy such as alpha-tocopherol acts as a scavenger of lipid peroxyl radicals attenuating the oxidative stress, which decreases the formation of oxLDL. The present study was designed to investigate the influence of the alpha-tocopherol supplementation on the concentration of electronegative low-density lipoprotein [LDL(-)], a minimally oxidized LDL, which we have previously described to be high in HD patients. Methods. Blood samples were collected before and after 120 days of supplementation by alpha-tocopherol (400 UI/day) in 19 stable HD patients (50 +/- 7.8 years; 9 males). The concentrations of LDL(-) in blood plasma [using an anti-LDL- human monoclonal antibody (mAb)] and the anti-LDL(-) IgG auto-antibodies were determined by ELISA. Calculation of body mass index (BMI) and measurements of waist circumference (WC), triceps skin folds (TSF) and arm muscle area (AMA) were performed. Results. The plasma alpha-tocopherol levels increased from 7.9 mu M (0.32-18.4) to 14.2 mu M (1.22-23.8) after the supplementation (P = 0.02). The mean concentration of LDL(-) was reduced from 570.9 mu g/mL (225.6-1241.0) to 169.1 mu g/mL (63.6-621.1) (P < 0.001). The anti-LDL(-) IgG auto-antibodies did not change significantly after the supplementation. The alpha-tocopherol supplementation also reduced the total cholesterol and LDL-C levels in these patients, from 176 +/- 42.3 mg/dL to 120 +/- 35.7 mg/dL (P < 0.05) and 115.5 +/- 21.4 mg/dL to 98.5 +/- 23.01 mg/dL (P < 0.001), respectively. Conclusion. The oral administration of alpha-tocopherol in HD patients resulted in a significant decrease in the LDL(-), total cholesterol and LDL-C levels. This effect may favour a reduction in cardiovascular risk in these patients, but a larger study is required to confirm an effect in this clinical setting.

On the mechanisms of phenothiazine-induced mitochondrial permeability transition: Thiol oxidation, strict Ca(2+) dependence, and cyt c release

Phenothiazines (PTZ) are drugs widely used in the treatment of schizophrenia. Trifluoperazine, a piperazinic PTZ derivative, has been described as inhibitor of the mitochondrial permeability transition (MPT). We reported previously the antioxidant activity of thioridazine at relatively low concentrations associated to the inhibition of the MPT (Brit. J. Pharmacol., 2002;136:136-142). In this study, it was investigated the induction of MPT by PTZ derivatives at concentrations higher than 10 mu M focusing on the molecular mechanism involved. PTZ promoted a dose-response mitochondrial swelling accompanied by mitochondrial transmembrane potential dissipation and calcium release, being thioridazine the most potent derivative. PTZ-induced MPT was partially inhibited by CsA or Mg(2+) and completely abolished by the abstraction of calcium. The oxidation of reduced thiol group of mitochondrial membrane proteins by PTZ was upstream the VIP opening and it was not sufficient to promote the opening of PTP that only occurred when calcium was present in the mitochondrial matrix. EPR experiments using DMPO as spin trapping excluded the participation of reactive oxygen species on the PTZ-induced MPT. Since 117 give rise to cation radicals chemically by the action of peroxidases and cyanide inhibited the PTZ-induced swelling, we propose that VIZ bury in the inner mitochondrial membrane and the chemically generated 117 cation radicals modify specific thiol groups that in the presence of Ca(2+) result in MPT associated to cytochrome c release. These findings contribute for the understanding of mechanisms of MET induction and may have implications for the cell death induced by PTZ. (C) 2010 Elsevier Inc. All rights reserved.

Impact of adenosine nucleotide translocase (ANT) proline isomerization on Ca(2+)-induced cysteine relative mobility/mitochondrial permeability transition pore

Mitochondrial membrane carriers containing proline and cysteine, such as adenine nucleotide translocase (ANT), are potential targets of cyclophilin D (CyP-D) and potential Ca(2+)-induced permeability transition pore (PTP) components or regulators; CyP-D, a mitochondrial peptidyl-prolyl cis-trans isomerase, is the probable target of the PTP inhibitor cyclosporine A (CsA). In the present study, the impact of proline isomerization (from trans to cis) on the mitochondrial membrane carriers containing proline and cysteine was addressed using ANT as model. For this purpose, two different approaches were used: (i) Molecular dynamic (MD) analysis of ANT-Cys(56) relative mobility and (ii) light scattering techniques employing rat liver isolated mitochondria to assess both Ca(2+)-induced ANT conformational change and mitochondrial swelling. ANT-Pro(61) isomerization increased ANT-Cys(56) relative mobility and, moreover, desensitized ANT to the prevention of this effect by ADP. In addition, Ca(2+) induced ANT ""c"" conformation and opened PTP; while the first effect was fully inhibited, the second was only attenuated by CsA or ADP. Atractyloside (ATR), in turn, stabilized Ca(2+)-induced ANT ""c"" conformation, rendering the ANT conformational change and PTP opening less sensitive to the inhibition by CsA or ADP. These results suggest that Ca(2+) induces the ANT ""c"" conformation, apparently associated with PTP opening, but requires the CyP-D peptidyl-prolyl cis-trans isomerase activity for sustaining both effects.

Dehydromonocrotaline induces cyclosporine A-insensitive mitochondrial permeability transition/cytochrome c release

Monocrotaline (MCT) is a pyrrolizidine alkaloid present in plants of the genus Crotalaria that causes cytotoxicity and genotoxicity in animals and humans. It is well established that the toxicity of MCT results from its hepatic bioactivation to dehydromonocrotaline (DHM), an alkylating agent, but the exact mechanism of action remains unknown. In a previous study, we demonstrated DHM`s inhibition of mitochondrial NADH-dehydrogenase activity at micromolar concentrations, which is an effect associated with a significant reduction in ATP synthesis. As a follow-up study, we have evaluated the ability of DHM to induce mitochondrial permeability transition (MPT) and its associated processes in isolated rat liver mitochondria. In the presence of 10 mu M Ca(2+), DHM (50-250 mu M) elicited MPT in a concentration-dependent, but cyclosporine A-independent manner, as assessed by mitochondrial swelling, which is associated with mitochondrial Ca(2+) efflux and cytochrome c release. DHM (50-250 mu M) did not cause hydrogen peroxide accumulation but did deplete endogenous glutathione and NAD(P)H, while oxidizing protein thiol groups. These results potentially indicate the involvement of mitochondria, via apoptosis, in the well-documented cytotoxicity of monocrotaline. (C) 2009 Elsevier Ltd. All rights reserved.

Ca(2+) binding to c-state of adenine nucleotide translocase (ANT)-surrounding cardiolipins enhances (ANT)-Cys(56) relative mobility: A computational-based mitochondrial permeability transition study

The oxidation of critical cysteines/related thiols of adenine nucleotide translocase (ANT) is believed to be an important event of the Ca(2+)-induced mitochondrial permeability transition (MPT), a process mediated by a cyclosporine A/ADP-sensitive permeability transition pores (PTP) opening. We addressed the ANT-Cys(56) relative mobility status resulting from the interaction of ANT/surrounding cardiolipins with Ca(2+) and/or ADP by means of computational chemistry analysis (Molecular Interaction Fields and Molecular Dynamics studies), supported by classic mitochondrial swelling assays. The following events were predicted: (i) Ca(2+) interacts preferentially with the ANT surrounding cardiolipins bound to the H4 helix of translocase, (ii) weakens the cardiolipins/ANT interactions and (iii) destabilizes the initial ANT-Cys(56) residue increasing its relative mobility. The binding of ADP that stabilizes the conformation ""m"" of ANT and/or cardiolipin, respectively to H5 and H4 helices, could stabilize their contacts with the short helix h56 that includes Cys(56), accounting for reducing its relative mobility. The results suggest that Ca(2+) binding to adenine nucleotide translocase (ANT)-surrounding cardiolipins in c-state of the translocase enhances (ANT)-Cys(56) relative mobility and that this may constitute a potential critical step of Ca(2+)-induced PTP opening. (C) 2009 Elsevier B.V. All rights reserved.

Molecular dynamics, density functional, ADMET predictions, virtual screening, and molecular interaction field studies for identification and evaluation of novel potential CDK2 inhibitors in cancer therapy

In this work, we have used molecular dynamics, density functional theory, virtual screening, ADMET predictions, and molecular interaction field studies to design and propose eight novel potential inhibitors of CDK2. The eight molecules proposed showed interesting structural characteristics that are required for inhibiting the CDK2 activity and show potential as drug candidates for the treatment of cancer. The parameters related to the Rule of Five were calculated, and only one of the molecules violated more than one parameter. One of the proposals and one of the drug-like compounds selected by virtual screening indicated to be promising candidates for CDK2-based cancer therapy.

Gene expression analysis of Paracoccidioides brasiliensis transition from conidium to yeast cell

Paracoccidioides brasiliensis infectious process relies on the initial expression of virulence faactors that are assumed to be controlled by molecular mechanisms through which the conidia and/or mycelial fragments convert to yeast cells. In order to analyze the profile of the thermally-induced dimorphic gene expression, 48 h C-L transition cultures which had been incubated at 36 degrees C were studied. By this time approximately 50% of the conidial population had already reverted to yeast form cells. At this transition time, an EST-Orestes library was constructed and characterized. As a result, 79 sequences were obtained, of which 39 (49.4%) had not been described previously in other libraries of this fungus and which could represent novel exclusive C-Y transition genes. Two of these sequences are, among others, cholestanol delta-isomerase, and electron transfer flavoprotein-ubiquinoneoxidoreductase (ETF-QO). The other 40 (50.6%) sequences were shared with Mycelia (M), Yeast (Y) or Mycelia to yest transition (M-Y) libraries. An important component of this group of sequences is a putative response regulator receiver SKN7, a protein of high importance in stress adaptation and a regulator of virulence in some bacteria and fungi. This is the first report identifying genes expressed during the C-Y transition process, the initial step required to understand the natural history of P brasiliensis conidia induced infection.

Photochemical Reactions of fac-[Mn(CO)(3)(phen)imidazole](+): Evidence for Long-Lived Radical Species Intermediates

The electronic absorption spectrum of fac[Mn(CO)(3)(phen)imH](+), fac-1 in CH(2)Cl(2) is characterized by a strong absorption band at 378 nm (epsilon(max) = 3200 mol(-1) L cm(-1)). On the basis of quantum mechanical calculations, the visible absorption band has been assigned to ligand-to-ligand charge-transfer (LLCT, im -> phen) and metal-to-ligand charge-transfer (MLCT, Mn -> phen) charge transfer transition. When fac-1 in CH(2)Cl(2) is irradiated with 350 nm continuous light, the absorption features are gradually shifted to represent those of the meridional complex mer-[Mn(CO)(3)(phen)imH](+), mer-1 (lambda(max) = 556 nm). The net photoreaction under these conditions is a photoisomerization, although, the presence of the long-lived radical species was also detected by (1)H NMR and FTIR spectroscopy. 355 nm continuous photolysis of fac-1 in CH(3)CN solution also gives the long-lived intermediate which is readly trapped by metylviologen (MV(2+)) giving rise to the formation of the one-electron reduced methyl viologen (MV(center dot+)). The UV-vis spectra monitored during the slow (45 min) thermal back reaction exhibited isosbestic conversion at 426 nm. On the basis of spectroscopic techniques and quantum mechanical calculations, the role of the radicals produced is analyzed.

Electrochemical oxidation of acid black 210 dye on the boron-doped diamond electrode in the presence of phosphate ions: Effect of current density, pH, and chloride ions

The electrochemical oxidation of acid black 210 dye (AB-210) on the boron-doped diamond (BDD) was investigated under different pH conditions. The best performance for the AB-210 oxidation occurred in alkaline phosphate solution. This is probably due to oxidizing agents such as phosphate radicals and peroxodiphosphate ions, which can be electrochemically produced with good yields on the BDD anode, mainly in alkaline solution. Under this condition, the COD (chemical oxygen demand) removal was higher than that obtained from the model proposed by Comninellis. Electrolyses performed in phosphate buffer and in the presence of chloride ions resulted in faster COD and color removals in acid and neutral solutions, but in alkaline phosphate solution, a better performance in terms of TOC removal was obtained in the absence of chloride. Moreover, organochloride compounds were detected in all electrolyses performed in the presence of chloride. The AB-210 electrooxidation on BDD using phosphate as supporting electrolyte proved to be interesting since oxidizing species generated from phosphate ions were able to completely degrade the dye without producing organochloride compounds. (C) 2009 Elsevier Ltd. All rights reserved.

Loss of Ergodicity in the Transition from Annealed to Quenched Disorder in a Finite Kinetic Ising Model

We consider a kinetic Ising model which represents a generic agent-based model for various types of socio-economic systems. We study the case of a finite (and not necessarily large) number of agents N as well as the asymptotic case when the number of agents tends to infinity. The main ingredient are individual decision thresholds which are either fixed over time (corresponding to quenched disorder in the Ising model, leading to nonlinear deterministic dynamics which are generically non-ergodic) or which may change randomly over time (corresponding to annealed disorder, leading to ergodic dynamics). We address the question how increasing the strength of annealed disorder relative to quenched disorder drives the system from non-ergodic behavior to ergodicity. Mathematically rigorous analysis provides an explicit and detailed picture for arbitrary realizations of the quenched initial thresholds, revealing an intriguing ""jumpy"" transition from non-ergodicity with many absorbing sets to ergodicity. For large N we find a critical strength of annealed randomness, above which the system becomes asymptotically ergodic. Our theoretical results suggests how to drive a system from an undesired socio-economic equilibrium (e. g. high level of corruption) to a desirable one (low level of corruption).

Low- and high-density lipoprotein cholesterol goal attainment in dyslipidemic women: The Lipid Treatment Assessment Project (L-TAP) 2

Background Differences between women and men have been documented for both diagnostic testing and treatment in cardiology. This analysis evaluates whether low-density lipoprotein cholesterol (LDL-C) success rates according to current guidelines and high-density lipoprotein cholesterol (HDL-C) levels differ by gender in the L-TAP 2 population. Methods Patients aged >= 20 years with dyslipidemia on stable lipid-lowering therapy were assessed in 9 countries between September 2006 and April 2007. Low-density lipoprotein cholesterol goal attainment by cardiovascular risk level and region and determinants of low HDL-C were compared between genders. Results Of 9,955 patients (45.3% women) evaluated, women had a significantly lower overall LDL-C success rate than men (71.5% vs 73.7%, P = .014), due entirely to the difference in the high-risk/coronary heart disease (CHD) group (LDL-C goal <100 mg/dL, 62.6% vs 70.6%, P < .0001) Among CHD patients with >= 2 additional risk factors, only 26.7% of women and 31.5% of men (P = .021) attained the optional LDL-C goal of <70 mg/dL. High-density lipoprotein cholesterol was <50 mg/dL in 32.2% of women and <40 mg/dL in 26.8% of men (P < .0001), including 38.2% of women and 29.8% of men in the high risk/CHD group (P < .0001). Predictors of low HDL-C in women included diabetes, smoking, waist circumference, and hypertension. Conclusions Cholesterol treatment has, improved substantially since the original L-TAP a decade ago, when only 39% of women attained their LDL-C goal. However, high-risk women are undertreated compared to men, and a substantial opportunity remains to reduce their cardiovascular risk. (Am Heart J 2009; 158:860-6.)

Transfer of Cholesterol and Other Lipids From a Lipid Nanoemulsion to High-density Lipoprotein in Heart Transplant Patients

Background: Beyond the first year after a heart transplant (HT) procedure, patients often develop dyslipidemias, which may be implicated in the genesis of transplant coronary heart disease. High-density lipoprotein (HDL) has a several anti-atherogenic properties, but the status of HDL in HT patients is still controversial. Nonetheless, determination of HDL cholesterol concentration is not sufficient for evaluation of the overall HDL protective role. In this study, a fundamental functional property of HDL, the ability to simultaneously receive the major lipid classes, was tested in HT patients. Methods: Twenty HT patients and 20 healthy normolipidemic subjects paired for gender, age and body mass index were studied. Blood samples were collected after 12-hour fasting for determination of plasma lipids, glucose, paraxonase I (PON 1) activity, HDL diameter and transfer of labeled lipids from an artificial nanoemulsion to HDL. Results: Plasma triglycerides (159 +/- 63 vs 94 +/- 35 mg/dl) and glucose (104 +/- 20 vs 86 +/- 10 mg/dl) were greater in HT patients than in control subjects. HDL cholesterol was lower and HDL diameter was smaller in the HT group (HDL cholesterol: 44 +/- 11 vs 55 +/- 15 mg/dl; HDL diameter: 8.8 +/- 0.6 vs 9.0 +/- 1.2 nm). PON 1 activity did not differ (87 +/- 47 vs 75 +/- 37 nmol/min/ml). The transfer rates of free cholesterol and cholesteryl esters were diminished in HT patients (HT: 8.4 +/- 1.2% and 3.8 +/- 0.6%; controls: 9.7 +/- 1.9% and 4.7 +/- 1.2%, respectively). Conclusions: The transfer of free cholesterol and cholesteryl esters to HDL is diminished in HT patients; disturbance in the ability of HDL to receive lipids may affect the anti-atherogenic properties of the lipoprotein. J Heart Lung Transplant 2009;28:1075-80. Copyright (C) 2009 by the International Society for Heart and Lung Transplantation.

Lipid Treatment Assessment Project 2 A Multinational Survey to Evaluate the Proportion of Patients Achieving Low-Density Lipoprotein Cholesterol Goals

Background-Information about physicians` adherence to cholesterol management guidelines remains scant. The present survey updates our knowledge of lipid management worldwide. Methods and Results-Lipid levels were determined at enrollment in dyslipidemic adult patients on stable lipid-lowering therapy in 9 countries. The primary end point was the success rate, defined as the proportion of patients achieving appropriate low-density lipoprotein cholesterol (LDL-C) goals for their given risk. The mean age of the 9955 evaluable patients was 62 +/- 12 years; 54% were male. Coronary disease and diabetes mellitus had been diagnosed in 30% and 31%, respectively, and 14% were current smokers. Current treatment consisted of a statin in 75%. The proportion of patients achieving LDL-C goals according to relevant national guidelines ranged from 47% to 84% across countries. In low-, moderate-, and high-risk groups, mean LDL-C was 119, 109, and 91 mg/dL and mean high-density lipoprotein cholesterol was 62, 49, and 50 mg/dL, respectively. The success rate for LDL-C goal achievement was 86% in low-, 74% in moderate-, and 67% in high-risk patients (73% overall). However, among coronary heart disease patients with >= 2 risk factors, only 30% attained the optional LDL-C goal of < 70 mg/dL. In the entire cohort, high-density lipoprotein cholesterol was < 40 mg/dL in 19%, 40 to 60 mg/dL in 55%, and > 60 mg/dL in 26% of patients. Conclusions-Although there is room for improvement, particularly in very-high-risk patients, these results indicate that lipid-lowering therapy is being applied much more successfully than it was a decade ago. (Circulation. 2009; 120: 28-34.)

Is Coronary Artery Calcification Associated with Vertebral Bone Density in Nondialyzed Chronic Kidney Disease Patients?

Background and objectives Low bone mineral density and coronary artery calcification (CAC) are highly prevalent among chronic kidney disease (CKD) patients, and both conditions are strongly associated with higher mortality. The study presented here aimed to investigate whether reduced vertebral bone density (VBD) was associated with the presence of CAC in the earlier stages of CKD. Design, setting, participants, & measurements Seventy-two nondialyzed CKD patients (age 52 +/- 11.7 years, 70% male, 42% diabetics, creatinine clearance 40.4 +/- 18.2 ml/min per 1.73 m(2)) were studied. VBD and CAC were quantified by computed tomography. Results CAC > 10 Agatston units (AU) was observed in 50% of the patients (median 120 AU [interquartile range 32 to 584 AU]), and a calcification score >= 400 AU was found in 19% (736 [527 to 1012] AU). VBD (190 +/- 52 Hounsfield units) correlated inversely with age (r = -0.41, P < 0.001) and calcium score (r = -0.31, P = 0.01), and no correlation was found with gender, creatinine clearance, proteinuria, lipid profile, mineral parameters, body mass index, and diabetes. Patients in the lowest tertile of VBD had expressively increased calcium score in comparison to the middle and highest tertile groups. In the multiple logistic regression analysis adjusting for confounding variables, low VBD was independently associated with the presence of CAC. Conclusions Low VBD was associated with CAC in nondialyzed CKD patients. The authors suggest that low VBD might constitute another nontraditional risk factor for cardiovascular disease in CKD. Clin J Am Soc Nephrol 6: 1456-1462, 2011. doi: 10.2215/CJN.10061110

Reaching C-Reactive Protein and Low-Density Lipoprotein Cholesterol Goals in Dyslipidemic Patients (from the Lipid Treatment Assessment Project [L-TAP] 2)

The purpose of the present substudy of the Lipid Treatment Assessment Project 2 was to assess dual C-reactive protein (CRP) and low-density lipoprotein (LDL) cholesterol goal attainment across a spectrum of low-, moderate-, and high-risk patients with dyslipidemia in 8 countries in North America, Latin America, Europe, and Asia. Of the 9,518 patients studied overall, 45% were women, 64% had hypertension, 31% had diabetes, 14% were current smokers, 60% were high risk, and 79% were taking a statin. The median CRP level was 1.5 mg/L (interquartile range 0.2 to 2.8). On multivariate analysis, higher CRP levels were associated with older age, female gender, hypertension, current smoking, greater body mass index, larger waist circumference, LDL cholesterol level, and triglyceride/high-density lipoprotein cholesterol ratio. In contrast, being from Asia or taking a statin was associated with lower levels. Across all risk groups, 59% of patients attained the CRP target of <2 mg/L, and 33% had <1 mg/L. Overall, 44% of patients attained both their National Cholesterol Education Program Adult Treatment Panel III LDL cholesterol target and a CRP level of <2 mg/L, but only 26% attained their LDL cholesterol target and a CRP level of <1 mg/L. In the very high-risk group with coronary heart disease and >= 2 risk factors, only 19% attained both their LDL cholesterol goal and a CRP level of <2 mg/L and 12% their LDL cholesterol goal and a CRP level of <1 mg/L. In conclusion, with current treatment, most dyslipidemic patients do not reach the dual CRP and LDL cholesterol goals. Smoking cessation, weight reduction, and the greater use of more potent statins at higher doses might be able to improve these outcomes. (C) 2011 Elsevier Inc. All rights reserved. (Am J Cardiol 2011;107:1639-1643)