Plaque components affect wall stress in stented human carotid artery: A numerical study

Carotid artery stenting presents challenges of in-stent restenosis and late thrombosis, which are caused primarily by alterations in the mechanical environment of the artery after stent implantation. The present study con-structed patient-specific carotid arterial bifurcation models with lipid pools and calcified components based on magnetic resonance imaging. We numerically analyzed the effects of multicomponent plaques on the distributions of von Mises stresses (VMSs) in the patient-specific models after stenting. The results showed that when a stent was deployed, the large soft lipid pool in atherosclerotic plaques cushioned the host artery and reduced the stress within the arterial wall;how-ever, this resulted in a sharp increase of VMS in the fibrous cap. When compared with the lipid pool, the presence of the calcified components led to slightly increased stresses on the luminal surface. However, when a calcification was located close to the luminal surface of the host artery and the stenosis, the local VMS was elevated. Overall, compared with calcified components, large lipid pools severely dam-aged the host artery after stenting. Furthermore, damage due to the calcified component may depend on location.     

Novel enzyme-linked immunosorbent assay for determination of fluvastatin in plasma at picogram level

For the first time, an enzyme-linked immunosorbent assay (ELISA) has been developed and validated for the determination of fluvastatin (FLV) in plasma samples at picogram level. The assay employed a polyclonal antibody that specifically recognizes FLV with high affinity, and FLV conjugate of bovine serum albumin (FLV-BSA) immobilized onto microplate wells as a solid-phase. The assay involved a competitive binding reaction between FLV, in plasma sample, and the immobilized FLV-BSA for the binding sites on a limited amount of the anti-FLV antibody. The bound anti-FLV antibody was quantified with horseradish peroxidase-labeled second anti-rabbit IgG antibody (HRP-IgG) and 3,3′,5,5′-tetramethylbenzidine (TMB) as a substrate for the peroxidase enzyme. The concentration of FLV in the sample was quantified by its ability to inhibit the binding of the anti-FLV antibody to the immobilized FLV-BSA and subsequently the color intensity in the assay wells. The conditions for the proposed ELISA were investigated and the optimum conditions were employed in the determination of FLV in plasma samples. The assay limit of detection was 10 pg mL⁻¹ and the effective working range at relative standard deviations (RSD) of ≤5% was 20-1000 pg mL⁻¹. Analytical recovery of FLV from spiked plasma was 97.1-102.7 ± 2.85-6.25%. The precision of the assay was satisfactory; RSD was 2.46-5.37 and 3.19-6.64% for the intra- and inter-assay precision, respectively. The analytical procedure is convenient, and one can analyze ∼200 samples per working day, facilitating the processing of large-number batch of samples. The proposed ELISA has a great value in routine analysis of FLV for its therapeutic monitoring and pharmacokinetic studies.     

Facile preparation of Fe2O3 nanoparticles mediated by Centaurea alba extract and assessment of the anti-atherosclerotic properties

This research work attempts to synthesize iron nanoparticles with Centaurea alba extract. The reported synthesis method serves to be more effective over conventional physical and chemical methods, which is found to be cost effective, recyclable, biocompatible and prevents oxidation of iron oxide nanoparticle as well.As the extract of Centaurea alba possess high content of flavonoids, tannins and phenolic acids, it thereby prevents the oxidation and accumulation iron oxide NPs. The morphological features of the obtained nanoparticle were determined by TEM and SEM imaging techniques. Furthermore, various spectroscopic techniques including UV-Vis, FT-IR has been evaluated.As a part of cellular and molecular studies, the prepared FeNPs was subjected to MTT assay for 48h on normal (HUVEC) cells to evaluate its cytotoxicity. The IC50 of FeNPs and BHT against DPPH free radicals were 287 and 191 µg/mL respectively. Male Wistar rats were selected as the model organism for the in vivo studies and has been categorized into 6 groups, where normal diet was provided to the control group, cholesterol diet was provided to sham group (HCD: 1.50% cholesterol and 24.00% fat) and HCD was provided to other groups. FeNPs were infused at low (100µg Kg^-1), moderate (200 µg/Kg) and maximum (400 µg/Kg) doses via gavages. Additionally, atorvastatin (10 mg Kg^-1) was provided to the last group through gavages with HCD. Six months has been fixed as a study period for all the groups. Various parameters including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) was assessed in the blood samples of the test organism at the end of the period. Furthermore, sections of coronary artery and aortic arteries were subjected to histopathological examinations, which showed increase in vessel wall thickness in HCD group, however FeNPstreated groups showed no significant pathological changes. Decrease in TG, TC and LDL-C was observed upon treatment of HCD animals with FeNPs.     

Plasma thiols redox status by laser-induced fluorescence capillary electrophoresis

High concentrations of total plasma thiols such as cysteine and homocysteine are important risk factors for atherosclerosis and cardiovascular diseases. We have recently described a new laser-induced fluorescence capillary electrophoresis (CE-LIF) method to measure total plasma thiols, in which the baseline separation of cysteinylglycine, homocysteine, cysteine, and glutathione was achieved by adding the organic base N-methyl-D-glucamine to the run buffer. However, because the active fractions of homocysteine and cysteine responsible for vascular injuries are still unknown, research calls for a set up of methods able to analyze different forms of plasma thiols. In this paper, we present an improvement of our previous method that allows the measurement of different thiol forms. Total, reduced, and free thiols were measured by varying the order of disulfide reduction with tributylphosphine and proteins precipitation with 5-sulfosalicylic acid. After derivatization with 5-iodoacetamidofluorescein, samples were separated and measured by CE-LIF using a phosphate/borate buffer in the presence of 75 mmol/L N-methyl-D-glucamine. Oxidized thiols and protein bound thiols were calculated by difference, free minus reduced and total minus free form, respectively. Linearity, reproducibility, analytical recovery, and sensitivity were evaluated. The assay was used to measure the thiols redox status in 15 plasma samples from healthy volunteers.     

Metabonomics study of atherosclerosis rats by ultra fast liquid chromatography coupled with ion trap-time of flight mass spectrometry

An ultra fast liquid chromatography coupled with IT-TOF mass spectrometry (UFLC/MS-IT-TOF) metabonomic approach was employed to study the plasma and urine metabolic profiling of atherosclerosis rats. Acquired data were subjected to principal component analysis (PCA) for differentiating the atherosclerosis and the control groups. Potential biomarkers were screened by using S-plot and were identified by the accurate mass and MSⁿ fragments information obtained from UFLC/MS-IT-TOF analysis. 12 metabolites in rat plasma and 8 metabolites in urine were identified as potential biomarkers. Concentrations of leucine, phenylalanine, tryptophan, acetylcarnitine, butyrylcarnitine, propionylcarnitine and spermine in plasma and 3-O-methyl-dopa, ethyl N2-acetyl-l-argininate, leucylproline, glucuronate, t6A N(6)-(N-threonylcarbonyl)-adenosine and methyl-hippuric acid in urine decreased in atherosclerosis rats. Ursodeoxycholic acid, chenodeoxycholic acid, LPC (C16:0), LPC (C18:0) and LPC (C18:1) in plasma and hippuric acid in urine were in higher levels in atherosclerosis rats. The alterated metabolites demonstrated abnormal metabolism of phenylalanine, tryptophan, bile acids and amino acids. This research proved that metabonomics is a promising tool for disease research.     

SMS高表达对细胞内和培养基中SM水平的影响

为了研究神经鞘磷脂合成酶(SMS)活性与神经鞘磷脂(SM)代谢之间的关系,用SMS的同功酶(SMS1和SMS2)的表达载体(pCMV. sport 6- SMS1和pcDNA3.1-SMS2), 瞬时转染HEK293细胞, 通过薄层层析法测定神经鞘磷脂合成酶活性来检测SMS的表达水平, 同时测定细胞和培养基中的SM浓度. 结果显示, 用pCMV. sport 6-SMS1转染细胞后与对照组相比, SMS表达水平提高65%, 细胞内和培养基中的SM水平显著性升高(58%和46%, p＜0.01); 转染pCDNA3.1-SMS2后与对照组相比, SMS表达水平提高13%, 细胞内和培养基中的SM水平显著性升高(33%和 29%, p＜0.05). 实验结果表明, SM水平可被SMS1和SMS2调节. 由于SM是冠心病和动脉粥样硬化的独立危险因子, 因此本文研究结果有可能为冠心病和动脉粥样硬化的治疗提供新的靶点.     

血管活性物质与动脉粥样硬化

动脉粥样硬化（Ａｔｈｅｒｏｓｃｌｅｒｏｓｉｓ Ａｓ）是当前危害人类健康最严重的疾病之一,一氧化氮、内皮素、前列环素和血栓素四种血管活性物质、在动脉粥样硬化的发生和发展过程中起重要作用。     

MRI-based biomechanical imaging: initial study on early plaque progression and vessel remodeling

The goal of the study is to develop a noninvasive magnetic resonance imaging (MRI)-based biomechanical imaging technique to address biomechanical pathways of atherosclerotic progression and regression in vivo using a 3D fluid-structure interaction (FSI) model. Initial in vivo study was carried out in an early plaque model in pigs that underwent balloon-overstretch injury to the left carotid arteries. Consecutive MRI scans were performed while the pigs were maintained on high cholesterol (progression) or normal chow (regression), with an injection of a plaque-targeted contrast agent, Gadofluorine M. At the end of study, the specimens of carotid arterial segments were dissected and underwent dedicated mechanical testing to determine their material properties. 3D FSI computational model was applied to calculate structure stress and strain distribution. The plaque structure resembles early plaque with thickened intima. Lower maximal flow shear stress correlates with the growth of plaque volume during progression, but not during regression. In contrast, maximal principle structure stress/stain (stress-P1 and strain-P1) were shown to correlate strongly with the change in the plaque dimension during regression, but moderately during progression. This MRI-based biomechanical imaging method may allow for noninvasive dynamic assessment of local hemodynamic forces on the development of atherosclerotic plaques in vivo.     

Conditional GWAS revealing genetic impacts of lifestyle behaviors on low-density lipoprotein (LDL)

BackgroundAccumulation of LDL cholesterol (LDL-c) within artery walls is strongly associated with the initiation and progression of atherosclerosis development. This complex trait is affected by multifactor involving polygenes, environments, and their interactions. Uncovering genetic architecture of LDL may help to increase the understanding of the genetic mechanism of cardiovascular diseases.MethodsWe used a genetic model to analyze genetic effects including additive, dominance, epistasis, and ethnic interactions for data from the Multi-Ethnic Study of Atherosclerosis (MESA). Three lifestyle behaviors (reading, intentional exercising, smoking) were used as cofactor in conditional models.ResultsWe identified 156 genetic effects of 10 quantitative trait SNPs (QTSs) in base model and three conditional models. The total estimated heritability of these genetic effects was approximately 72.88% in the base model. Five genes (CELSR2, MARK2, ADAMTS12, PFDN4, and MAGI2) have biological functions related to LDL.ConclusionsCompared with the based model LDL, the results in three conditional models revealed that intentional exercising and smoking could have impacts for causing and suppressing some of genetic effects and influence the levels of LDL. Furthermore, these two lifestyles could have different genetic effects for each ethnic group on a specific QTS. As most of the heritability in based model LDL and conditional model LDL|Smk was contributed from epistasis effects, our result indicated that epistasis effects played important roles in determining LDL levels. Our study provided useful insight into the biological mechanisms underlying regulation of LDL and might help in the discovery of novel therapeutic targets for cardiovascular disease.     

Assessing the Progression of Early Atherosclerosis Mice Using a Fluorescence Nanosensor for the Simultaneous Detection and Imaging of pH and Phosphorylation

The inflammatory microenvironment involves changes in pH and protein phosphorylation state and is closely related to the occurrence and development of atherosclerosis (AS). Herein, we constructed a dual-detection fluorescence nanosensor PCN-NP-HPZ based on post modification of MOFs, which realized the simultaneous detection and imaging of pH and phosphorylation through the pH-sensitive group piperazine and the Zr^IV node of the MOFs. The sensors were used to monitor changes in blood pH and phosphate levels at different time stages during atherosclerotic plaque formation. Two-photon fluorescence imaging was also performed in the vascular endothelium. Blood tests combined with two-photon fluorescence images indicated that in the early stage of AS, blood and tissue pH levels were lower than that of the normal mice, while phosphate and tissue phosphorylation levels were higher than that of the normal mice. The present study provides a new analysis method for the assessment of early atherosclerotic disease.