Plaque progression and regression in atherothrombosis

Atherogenic index of plasma as a predictor of coronary artery disease: a cohort study in south of Iran

BACKGROUND

Coronary artery disease (CAD) is an atherosclerotic disease of an inflammatory nature. Previous studies examining the relationship between triglycerides and high-density lipoprotein cholesterol have highlighted the importance of plasma atherogenic index (AIP) as an important predictor of coronary heart disease. However, due to the lack of adequate information on this topic, this study aimed to investigate the relationship between AIP and coronary heart disease risk.

RESULTS

This study included 2,226 women and 1,690 men aged 35-70 years who participated in the Bandar Kong Cohort study and met the eligibility criteria. The data was collected using a checklist and questionnaires, which were designed by experienced individuals. After participants completed a registration form and gave informed consent, face-to-face interviews were conducted by trained experts. The validity and reliability of the questionnaire had been verified by the national cohort team prior to its use. The Ethics Committee of Hormozgan University of Medical Sciences (IR.HUMS.REC.1400.171) approved the study. Data from the initial cohort survey using SPSS software version 25, were analyzed to include several factors, including age, sex, smoking status, body mass index (BMI), physical activity level, socioeconomic status, AIP, systolic blood pressure, and diastolic blood pressure. The prevalence of coronary heart disease was found to be 7.5% higher in people with a BMI of 25 or higher. Also, Individuals with low physical activity had a higher prevalence. Individuals with CAD had significantly higher mean values for the AIP, age, systolic blood pressure, and diastolic blood pressure (0.46, 57.50, 128.43, and 81.10, respectively) compared to those without CAD. Furthermore, patients with CAD had lower years of education (2649.45 and 3.59) than individuals without CAD (P < 0.05). Importantly, our findings showed that AIP increased the odds ratio of coronary heart disease by 1.86 as an independent risk factor.

CONCLUSIONS

Based on our investigation, the AIP is a valuable and independent predictive risk factor for coronary artery disease. This index can be utilized effectively due to its accessibility and affordability, making it a promising tool for risk assessment in clinical settings.

The influence of blood velocity and vessel geometric parameters on wall shear stress

Vascular geometry was proposed to be one risk factor of atherosclerosis (AS). When developing this hypothesis, the discussion of geometry-wall shear stress (WSS) has often been included. However, further exploration on how various geometric parameters were affecting WSS was needed. The purpose of this study was to investigate the influence degree of vessel geometric parameters and blood velocity on WSS. A computational fluid dynamics (CFD) analyses of the vertebral and basilar arteries (VA and BA, respectively) was used. Twenty patients with no plaques or vessel wall thickening at the VA and BA were included. CFD analyses using both specific vessel models and flow conditions measured by ultrasound Doppler were performed. Subsequently, CFD results were post-processed with multiple linear regression to investigate numerical correlations between geometrical and flow parameters and WSS. The results of the multiple linear regression analysis further demonstrated that the BA proximal velocity was the most influential factor positively influencing BA WSS. The lower the WSS was, the stronger the influence brought by BA average diameter would be. The regression demonstrated that the contributions brought by average diameter and proximal velocity in lower WSS regions were lower than that in higher WSS regions. Tortuosity was only positively correlated with 97.5th WSS percentile, and vessel length and curvature showed no correlation with WSS. This study quantified the influence degree of BA morphology and flow velocity on WSS, which may have practical implications for predicting hemodynamic risks.

Comparative efficacy of Chinese patent medicines in patients with carotid atherosclerotic plaque: a Bayesian network meta- analysis

BACKGROUND

Traditional Chinese patent medicines (TCPMs) have been widely used to treat carotid atherosclerotic plaque (CAP) in China. However, systematic evaluation of the clinical efficacy of TCPMs for CAP is still unknown, and the comparative efficacy of different TCPMs is unclear.

OBJECTIVES

This study aims to compare and rank the effectiveness and safety of different TCPMs in treating CAP using a Bayesian network meta- analysis (NMA).

METHODS

This NMA was performed according to the Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) Extension Statement. Eight databases were searched from their inception to August 2023 for randomized controlled trials (RCTs). The articles regarding eligibility and extracted data were screened independently by two authors. The Cochrane Risk of Bias tool was used to evaluate quality and bias. The change of carotid artery intimal- medial thickness (IMT), carotid maximal plaque area, carotid atherosclerotic plaque Course score, serum lipid levels, CRP, and adverse events rate (AER) were used as outcomes. Data from each RCTs were first pooled using random- effect pairwise meta- analyses and illustrated as odds ratios (ORs) or standardized mean differences (SMDs) with 95% confidence interval (CI). NMAs were performed using Stata17.0 software and the GeMTC package of R software to evaluate the comparative effectiveness of TCPMs, and displayed as ORs or SMDs with 95% CI. A Bayesian hierarchical random- effects model was used to conduct NMAs using the Markov Chain Monte Carlo algorithm. The GRADE partially contextualised framework was applied for NMA result interpretation.

RESULTS

NMA included 27 RCT trials with 4131 patients and nine types of TCPMs. Pairwise meta- analyses indicated that Conventional Western medicine (CWM) + TCPM was superior to CWM in reducing the IMT (SMD: - 1.26; 95% CI - 1.59 to - 0.93), the carotid maximal plaque area (SMD - 1.27; 95% CI - 1.71, - 0.82) and the carotid atherosclerotic plaque Course score (SMD - 0.72; 95% CI 95% CI - 1.20, - 0.25). NMAs demonstrated that CWM + Jiangzhiling pill (JZL) with SUCRA 70.6% exhibited the highest effective intervention for reducing IMT. CWM + SXBX (Shexiang baoxin pill) was superior to other TCPMs in reducing the carotid maximal plaque area (83.0%), the atherosclerotic plaque Course score (92.5%), TC (95.6%) and LDL (92.6%) levels. CWM + NXT (Naoxintong capsule), CWM + XS (Xiaoshuang granules/enteric capsule), and CWM + ZBT (Zhibitai) were superior to other CPMs in improving TG (90.1%), HDL (86.1%), and CRP (92.6%), respectively. No serious adverse events were reported.

CONCLUSIONS

For CAP patients, CWM + XSBX was among the most effective in reducing carotid maximal plaque area, atherosclerotic plaque Course score, TC and LDL levels, and CWM + JZL was the most effective in reducing IMT. Overall, CWM + XSBX may be considered an effective intervention for the treatment of CAP. This study provides reference and evidence for the clinical optimization of TCPM selection in CAP treatment. More adequately powered, well- designed clinical trials to increase the quality of the available evidence are still needed in the future due to several limitations.

Novel Strategies in the Early Detection and Treatment of Endothelial Cell-Specific Mitochondrial Dysfunction in Coronary Artery Disease

Although elevated cholesterol and other recognised cardiovascular risk factors are important in the development of coronary artery disease (CAD) and heart attack, the susceptibility of humans to this fatal process is distinct from other animals. Mitochondrial dysfunction of cells in the arterial wall, particularly the endothelium, has been strongly implicated in the pathogenesis of CAD. In this manuscript, we review the established evidence and mechanisms in detail and explore the potential opportunities arising from analysing mitochondrial function in patient-derived cells such as endothelial colony-forming cells easily cultured from venous blood. We discuss how emerging technology and knowledge may allow us to measure mitochondrial dysfunction as a potential biomarker for diagnosis and risk management. We also discuss the "pros and cons" of animal models of atherosclerosis, and how patient-derived cell models may provide opportunities to develop novel therapies relevant for humans. Finally, we review several targets that potentially alleviate mitochondrial dysfunction working both via direct and indirect mechanisms and evaluate the effect of several classes of compounds in the cardiovascular context.

A Comprehensive Review: Epidemiological strategies, Catheterization and Biomarkers used as a Bioweapon in Diagnosis and Management of Cardio Vascular Diseases

Coronary artery disease (CAD) is a serious health problem that causes a considerable number of mortality in a number of affluent nations throughout the world. The estimated death encountered in many developed countries includes including Pakistan, reached 111,367 and accounted for 9.87% of all deaths, despite the mortality rate being around 7.2 million deaths per year, or 12% of all estimated deaths accounted annually around the globe, with improved health systems. Atherosclerosis progressing causes the coronary arteries to become partially or completely blocked, which results in CAD. Additionally, smoking, diabetes mellitus, homocystinuria, hypertension, obesity, hyperlipidemia, and psychological stress are risk factors for CAD. The symptoms of CAD include angina which is described as a burning, pain or discomfort in the chest, nausea, weakness, shortness of breath, lightheadedness, and pain or discomfort in the arms or shoulders. Atherosclerosis and thrombosis are the two pathophysiological pathways most frequently involved in acute coronary syndrome (ACS). Asymptomatic plaque disruption, plaque bleeding, symptomatic coronary blockage, and myocardial infarction are the prognoses for CAD. In this review, we will focus on medicated therapy which is being employed for the relief of angina linked with CAD including antiplatelet medicines, nitrates, calcium antagonists, blockers, catheterization, and the frequency of recanalized infarct-related arteries in patients with acute anterior wall myocardial infarction (AWMI). Furthermore, we have also enlightened the importance of biomarkers that are helpful in the diagnosis and management of CAD.

Novel Antithrombotic Agents in Ischemic Cardiovascular Disease: Progress in the Search for the Optimal Treatment

Ischemic cardiovascular diseases have a high incidence and high mortality worldwide. Therapeutic advances in the last decades have reduced cardiovascular mortality, with antithrombotic therapy being the cornerstone of medical treatment. Yet, currently used antithrombotic agents carry an inherent risk of bleeding associated with adverse cardiovascular outcomes and mortality. Advances in understanding the pathophysiology of thrombus formation have led to the discovery of new targets and the development of new anticoagulants and antiplatelet agents aimed at preventing thrombus stabilization and growth while preserving hemostasis. In the following review, we will comment on the key limitation of the currently used antithrombotic regimes in ischemic heart disease and ischemic stroke and provide an in-depth and state-of-the-art overview of the emerging anticoagulant and antiplatelet agents in the pipeline with the potential to improve clinical outcomes.

Association of eNOS (G894T, rs1799983) and KCNJ11 (E23K, rs5219) gene polymorphism with coronary artery disease in North Indian population

Background

Endothelial nitric oxide synthase (eNOS) and potassium voltage-gated channel subfamily J member 11 (KCNJ11) could be the candidate genes for coronary artery disease (CAD). This study investigated the relationship of the eNOS (rs1799983) and KCNJ11 (rs5219) polymorphisms with the presence and severity of CAD in the North Indian population.

Methods

This study included 300 subjects, 150 CAD cases and 150 healthy controls. Single nucleotide polymorphism was evaluated by Polymerase chain reaction and Restriction fragment length polymorphism (PCR-RFLP). Analysis was performed by SPSS (version 21.0).

Results

We observed that KK genotype of KCNJ11E23K (rs5219) polymorphism (P=0.0001) genotypes and K allele (P=0.0001) was found to be a positive risk factor and strongly associated with CAD. In the case of eNOSG894T (rs1799983) there was no association found with CAD.

Conclusion

These results illustrate the probability of associations between SNPs and CAD although specific genetic polymorphisms affecting ion channel function and expression have still to be clarified by further investigations involving larger cohorts.

Impact of Diabetes Mellitus on the Potential of Autologous Stem Cells and Stem Cell-Derived Microvesicles to Repair the Ischemic Heart

Ischemic heart disease remains the leading cause of morbidity and mortality worldwide. Despite the advances in medical management and catheter-based therapy, mortality remains high, as does the risk of developing heart failure. Regenerative therapies have been widely used as an alternative option to repair the damaged heart mainly because of their paracrine-related beneficial effects. Although cell-based therapy has been demonstrated as feasible and safe, randomized controlled trials and meta-analyses show little consistent benefit from treatments with adult-derived stem cells. Mounting evidence from our group and others supports that cardiovascular risk factors and comorbidities impair stem cell potential thus hampering their autologous use. This review aims to better understand the influence of diabetes on stem cell potential. For this purpose, we will first discuss the most recent advances in the mechanistic understanding of the effects of diabetes on stem cell phenotype, function, and molecular fingerprint to further elaborate on diabetes-induced alterations in stem cell extracellular vesicle profile. Although we acknowledge that multiple sources of stem or progenitor cells are used for regenerative purposes, we will focus on bone marrow hematopoietic stem/progenitor cells, mesenchymal stem cells residing in the bone marrow, and adipose tissue and briefly discuss endothelial colony-forming cells.

Impact of optical coherence tomography-derived neointimal tissue morphology on development of very late in-stent restenosis

OBJECTIVES

This study evaluated the progression of very late in-stent restenosis (VL-ISR) by analyzing four serial coronary angiography (CAG) images and its correlation with neointimal tissue characterization of the VL-ISR lesions on optical coherence tomography (OCT).

BACKGROUND

Recently, VL-ISR is occasionally observed beyond a few years after drug-eluting stents (DESs) implantation.

METHODS

This study analyzed 50 VL-ISR lesions after DES in which 4 serial CAGs over a period of 2 years, including at baseline procedure, 9 months after baseline procedure, 12 months before VL-ISR, and at the time of VL-ISR, were performed. Neointimal tissue characteristics by OCT were categorized as homogeneous, heterogeneous with invisible strut (Type I), heterogeneous with visible strut (Type II), speckled (Type III), or heterogeneous with sharply delineated border (Type IV).

RESULTS

From the development process, 23 VL-ISRs (46%) were categorized as rapid progression and 27 (54%) as gradual progression. The five categories of neointimal tissue composition significantly differed between lesions with rapid and gradual progression. Homogeneous neointima and Type IV heterogeneous neointima were observed only in lesions with gradual progression. Moreover, most Type I heterogeneous neointima was identified in lesions with gradual progression. Instead, main neointimal tissue components of lesions with rapid progression were Type II (43%) and Type III (43%) heterogeneous neointima.

CONCLUSION

The progression rate of in-stent atherosclerotic changes is gradual, whereas organized thrombus could be associated with an increased risk of rapid neointimal growth. The two types of stenosis progression provide a new insight into the mechanism of VL-ISR development after DES implantation.

Clopidogrel or prasugrel reduces mortality and lessens cardiovascular damage from acute myocardial infarction in hypercholesterolemic male rats

AIMS

Hypercholesterolemia is a hazard for increasing susceptibility of the heart to myocardial infarction (MI) by inducing platelet hyperaggregability. Clopidogrel and prasugrel have documented cardioprotective effects in clinical studies. Herein, we investigated whether clopidogrel and prasugrel could protect against isoproterenol-induced acute MI (A-MI) under hypercholesterolemic conditions in rats.

MAIN METHODS

Dietary hypercholesterolemic rats were subjected to acute doses of isoproterenol. Serum lipids, inflammatory markers, aortic endothelin1 and endothelial nitric oxide synthase (eNOS) mRNAs expression and immunexpression of BCL2 were determined.

KEY FINDINGS

Hypercholesterolemic rats showed infiltration of inflammatory cells and reduction in aortic wall thickness, deposition of fibrous tissue between cardiac muscle fibers. Protective doses of prasugrel or clopidogrel for 28 days before A-MI increased survival, amended the ECG parameters -including ST segment elevation- and improved the histopathological picture in hypercholesterolemic rats. This was coupled with reductions in platelet aggregation, creatine kinase-MB activity, endothelin 1, systemic inflammation and cardiac lipid peroxidation and increment in aortic eNOS expression. Clopidogrel and prasugrel groups showed enhanced BCL2 expression in cardiac fibers and aortic wall.

SIGNIFICANCE

Prasugrel and clopidogrel protected against A-MI via anti-aggregatory and anti-inflammatory effects. These results add to the value of these drugs in correcting cardiovascular dysfunction in patients vulnerable to A-MI after confirmation by appropriate human studies.

Human serum albumin nanoparticles loaded with phthalocyanine dyes for potential use in photodynamic therapy for atherosclerotic plaques

Diseases caused by obstruction or rupture of vulnerable plaques in the arterial walls such as cardiovascular infarction or stroke are the leading cause of death in the world. In the present work, we developed human serum albumin nanoparticles loaded by physisorption with zinc phthalocyanine, TT1, mainly used for industrial application as near-infrared photosensitizer and compared these to HSA NPs loaded with the well-known silicone phthalocyanine (Pc4). The use of NIR light allows for better tissue penetration, while the use of nanoparticles permits high local concentrations. The particles were characterized and tested for toxicity and stability as well as for their potential use as a contrast agent and NIR photosensitizer for photodynamic therapy in cardiovascular disease. We focused on the distribution of the nanoparticles in RAW264.7 macrophage cells and atherosclerotic mice. The nanoparticles had an average size of 120 nm according to dynamic light scattering, good loading capacity for zinc phthalocyanine, and satisfying stability in 50% (v/v) fetal bovine serum for 8 hours and in an aqueous environment at 4°C for 4–6 weeks. Under light irradiation we found a high production of singlet oxygen and the products showed no dark toxicity in vitro with macrophages (the target cells in vulnerable plaques), but at a low g/mL nanoparticle concentration killed efficiently the macrophages upon LED illumination. Injection of the contrast agent in atherosclerotic mice led to a visible fluorescence signal of zinc phthalocyanine in the atherosclerotic plaque at 30 minutes and in the lungs with a fast clearance of the nanoparticles. Zinc phthalocyanine loaded human serum albumin nanoparticles present an interesting candidate for the visualization and potentially photodynamic treatment of macrophages in atherosclerotic plaques.

A review on coronary artery disease, its risk factors, and therapeutics

Coronary artery disease (CAD) is one of the major cardiovascular diseases affecting the global human population. This disease has been proved to be the major cause of death in both the developed and developing countries. Lifestyle, environmental factors, and genetic factors pose as risk factors for the development of cardiovascular disease. The prevalence of risk factors among healthy individuals elucidates the probable occurrence of CAD in near future. Genome-wide association studies have suggested the association of chromosome 9p21.3 in the premature onset of CAD. The risk factors of CAD include diabetes mellitus, hypertension, smoking, hyperlipidemia, obesity, homocystinuria, and psychosocial stress. The eradication and management of CAD has been established through extensive studies and trials. Antiplatelet agents, nitrates, β-blockers, calcium antagonists, and ranolazine are some of the few therapeutic agents used for the relief of symptomatic angina associated with CAD.

Safety and Efficacy of Extremely Low LDL-Cholesterol Levels and Its Prospects in Hyperlipidemia Management

The risk of cardiovascular disease has been reported to have a linear relationship with LDL levels. Additionally, the currently recommended LDL target goal of 70 mg/dl does not diminish the CV risk entirely leaving behind some residual risk. Previous attempts to maximally lower the LDL levels with statin monotherapy have met dejection due to the increased side effects associated with the treatment. Nevertheless, with the new advancements in clinical medicine, it has now become possible to bring down the LDL levels to as low as 15 mg/dl using PCSK9 monoclonal antibodies alone or in combination with statins. The development of inclisiran, siRNA silencer targeting PCSK9 gene, is a one step forward in these endeavors. Moreover, various studies aiming to lower the CV risk and mortality by lowering LDL levels have demonstrated encouraging results. The current challenge is to explore this arena to redefine the target LDL levels, if required, to avoid any suboptimal treatment. After thorough literature search in the PubMed, Embase, Scopus, and Google Scholar, we present this article to provide a brief overview of the safety and efficacy of lowering LDL below the current goal.

Systems biology approaches to understand the effects of nutrition and promote health

Within the last years the implementation of systems biology in nutritional research has emerged as a powerful tool to understand the mechanisms by which dietary components promote health and prevent disease as well as to identify the biologically active molecules involved in such effects. Systems biology, by combining several '-omics' disciplines (mainly genomics/transcriptomics, proteomics and metabolomics), creates large data sets that upon computational integration provide in silico predictive networks that allow a more extensive analysis of the individual response to a nutritional intervention and provide a more global comprehensive understanding of how diet may influence health and disease. Numerous studies have demonstrated that diet and particularly bioactive food components play a pivotal role in helping to counteract environmental-related oxidative damage. Oxidative stress is considered to be strongly implicated in ageing and the pathophysiology of numerous diseases including neurodegenerative disease, cancers, metabolic disorders and cardiovascular diseases. In the following review we will provide insights into the role of systems biology in nutritional research and focus on transcriptomic, proteomic and metabolomics studies that have demonstrated the ability of functional foods and their bioactive components to fight against oxidative damage and contribute to health benefits.

ADAM-10 could mediate cleavage of N-cadherin promoting apoptosis in human atherosclerotic lesions leading to vulnerable plaque: a morphological and immunohistochemical study

Atherosclerosis remains a major cause of mortality. Whereas the histopathological progression of atherosclerotic lesions is well documented, much less is known about the development of unstable or vulnerable plaque, which can rupture leading to thrombus, luminal occlusion and infarct. Apoptosis in the fibrous cap, which is rich in vascular smooth muscle cells (VSMCs) and macrophages, and its subsequent weakening or erosion seems to be an important regulator of plaque stability. The aim of our study was to improve our knowledge on the biological mechanisms that cause plaque instability in order to develop new therapies to maintain atherosclerotic plaque stability and avoid its rupture. In our study, we collected surgical specimens from atherosclerotic plaques in the right or left internal carotid artery of 62 patients with evident clinical symptoms. Histopathology and histochemistry were performed on wax-embedded sections. Immunohistochemical localization of caspase-3, N-cadherin and ADAM-10 was undertaken in order to highlight links between apoptosis, as expressed by caspase-3 immunostaining, and possible roles of N-cadherin, a cell-cell junction protein in VSMCs and macrophages that provides a pro-survival signal reducing apoptosis, and ADAM-10, a "disintegrin and metalloproteases" that is able to cleave N-cadherin in glioblastomas. Our results showed that when apoptosis, expressed by caspase-3 immunostaining, increased in the fibrous cap, rich in VSMCs and macrophages, the expression of N-cadherin decreased. The decreased N-cadherin expression, in turn, was linked to increased ADAM-10 expression. This study shows that apoptotic events are probably involved in the vulnerability of atherosclerotic plaque.

Atherothrombotic risk in obesity

A link between obesity and coronary artery disease development has been repeatedly proposed, possibly in part due to the development of a proinflammatory and prothrombotic state in obese subjects. Adipocytes secrete numerous hormones and cytokines (adipokines) which influence gene expression and cell functions in endothelial cells, arterial smooth muscle cells, and monocytes/macrophages favouring the development of an atherosclerotic vulnerable plaque. Moreover, the release of such biologically active molecules also promotes endothelial function impairment, disturbs the haemostatic and fibrinolytic systems, and produces alterations in platelet function affecting the initiation, progression, and stabilization of thrombus formation upon atherosclerotic plaque rupture. In this review we will discuss the pathophysiological mechanisms by which obesity contributes to increase atherothrombosis paying special attention to its effects over thrombosis.

Plaque regression and plaque stabilisation in cardiovascular diseases

Atherosclerosis is characterized by formation of plaques on the inner walls of arteries that threatens to become the leading cause of death worldwide via its sequelae of myocardial infarction and stroke. Endothelial dysfunction leads to cholesterol uptake and accumulation of inflammatory markers within the plaque. The stability of a plaque eventually depends on the balance between vascular smooth muscle cells that stabilize it and the inflammatory cells like macrophages and T lymphocytes that make it prone to rupture. The current approach to manage atherosclerosis focuses on the treatment of a ruptured plaque and efforts have been made to reduce the risk of plaque rupture by identifying vulnerable plaques and treating them before they precipitate into clinical events. New diagnostic approaches such as IVUS and CIMT ultrasound are now being preferred over traditional coronary angiography because of their better accuracy in measuring plaque volume rather than the level of stenosis caused. The present review highlights the literature available on two prevalent approaches to manage a vulnerable plaque, namely, plaque stabilization and plaque regression, and their validation through various treatment modalities in recent plaque management studies. Plaque stabilization focuses on stabilizing the content of plaque and strengthening the overlying endothelium, while plaque regression focuses on the overall reduction in plaque volume and to reverse the arterial endothelium to its normal functional state. Although earlier studies contemplated the practicality of plaque regression and focused greatly on stabilization of a vulnerable plaque, our review indicated that, aided by the use of superior diagnostics tools, more intensive lipid modifying therapies have resulted in actual plaque regression.

Atherosclerosis, platelets and thrombosis in acute ischaemic heart disease

Atherosclerosis is the underlying reason for nearly all causes of coronary artery disease and peripheral arterial disease and many cases of stroke. Atherosclerosis is a systemic inflammatory process characterised by the accumulation of lipids and macrophages/lymphocytes within the intima of large arteries. The deposition of these blood borne materials and the subsequent thickening of the wall often significantly compromise the residual lumen leading to ischaemic events distal to the arterial stenosis. However, these initial fatty streak lesions may also evolve into vulnerable plaques susceptible to rupture or erosion. Plaque disruption initiates both platelet adhesion and aggregation on the exposed vascular surface and the activation of the clotting cascade leading to the so-called atherothrombotic process. Yet, platelets have also been shown to be transporters of regulatory molecules (micro-RNA), to drive the inflammatory response and mediate atherosclerosis progression. Here we discuss our current understanding of the pathophysiological mechanisms involved in atherogenesis - from fatty streaks to complex and vulnerable atheromas - and highlight the molecular machinery used by platelets to regulate the atherogenic process, thrombosis and its clinical implications.

Effects of dietary flaxseed on atherosclerotic plaque regression

Dietary flaxseed can retard the progression of atherosclerotic plaques. However, it remains unclear whether these antiatherogenic effects extend to plaque regression. In the present study, the therapeutic potential of dietary flaxseed on atherosclerotic plaque regression and vascular contractile function was evaluated using a novel rabbit model. Rabbits were randomly assigned to receive either a regular diet for 12 wk (group I) or a 1% cholesterol-supplemented diet for 4 wk followed by a regular diet for 8 wk (group II). The remaining experimental animals were treated as in group II but were fed for an additional 14 wk with either a regular diet (group III) or a 10% flaxseed-supplemented diet (group IV). Animals in group II showed clear evidence of plaque growth stabilization. Their vessels also exhibited significantly lower norepinephrine-induced contraction and an impaired relaxation response to acetylcholine compared with animals in group I. Dietary flaxseed supplementation resulted in a significant ≈40% reduction in plaque formation (P = 0.033). Animals in both groups II and III displayed improved contraction and endothelium-dependent vessel relaxation. Dietary flaxseed is a valuable strategy to accelerate the regression of atherosclerotic plaques; however, flaxseed intervention did not demonstrate a clear beneficial effect on the vessel contractile response and endothelium-dependent vasorelaxation.

Intima-medial thickness homogeneity in the common carotid artery: measurement method and preliminary clinical study

BACKGROUND

To propose and test in a preliminary clinical study a novel method for calculating intima-medial thickness (IMT) homogeneity (IMTH).

METHODS

IMT was measured off-line on every horizontal pixel line along the far wall of the common carotid artery, with previously validated software. IMTH was assessed by the SD, coefficient of variation, and interval distribution of obtained IMT values. This method was applied to 129 individuals (age, 40-60 years), including 49 healthy control subjects, 44 subjects at high risk of atherosclerosis, and 36 subjects with known atherosclerosis. Differences with a p value <0.05 were considered statistically significant.

RESULTS

SD and coefficient of variation were higher in the high-risk than in the control group, as well as in high-risk and control subgroups with maximal IMT = 0.8 mm or mean IMT = 0.55-0.65 mm. There were 85.7, 62.8, and 36% of IMT values in the 0.4- to 0.6-mm range and 0.89, 13.8, and 21.2% of IMT values in the 0.8- to 1.2-mm range in the control, high-risk, and atherosclerosis groups, respectively.

CONCLUSIONS

IMTH is a promising approach for the assessment of atherosclerosis, in addition to conventional IMT measurement. Further clinical studies are needed to assess its clinical usefulness.

Recombinant HDL(Milano) exerts greater anti-inflammatory and plaque stabilizing properties than HDL(wild-type)

OBJECTIVE

The aim of this study was to compare the effects of HDL(Milano) and HDL(wild-type), on regression and stabilization of atherosclerosis.

METHODS

Atherosclerotic New Zealand White rabbits received 2 infusions, 4 days apart, of HDL(Milano) (75mg/kg of apoA-I(Milano)), HDL(wild-type) (75mg/kg apoA-I(wild-type)) or placebo. Pre- and post-treatment plaque volume was assessed by MRI. Markers of plaque vulnerability and inflammation were evaluated. Liver and aortic cholesterol content, aortic ABCA-1 and liver SR-BI were quantified. The effect of apoA-I Milano and wild-type proteins on MCP-1 and COX-2 expression by macrophages was evaluated in vitro.

RESULTS

Both forms of HDL induced aortic plaque regression (-4.1% and -2.6% vs. pre-treatment in HDL(Milano) and HDL(wild-type) respectively, p<0.001 and p=0.009). A similar reduction in cholesterol content of aorta and liver was observed with both treatments vs. placebo. The expression of aortic ABCA-1 and hepatic SR-BI was significantly higher in both treated groups vs. placebo. A significantly reduced plaque macrophage density was observed in the HDL(Milano) vs. both HDL(wild-type) and placebo groups. Plaque levels of COX-2, MCP-1, Caspase-3 antigen and MMP-2 activity were significantly reduced in the HDL(Milano) vs. both HDL(wild-type) and placebo groups. In vitro studies showed that apoA-I(Milano) protein significantly reduced expression of COX-2 and MCP-1 in oxLDL loaded macrophages vs. apoA-I(wild-type).

CONCLUSIONS

Despite a similar effect on acute plaque regression, the infusion of HDL(Milano) exerts superior anti-inflammatory and plaque stabilizing effects than HDL(wild-type) in the short term.

Medical treatment of patients with intracranial atherosclerotic disease

The medical treatment of patients with symptomatic intracranial atherosclerotic disease (ICAD) is directed toward reducing the risk of new ischemic events. The overall strategy is divided into: (1) prevention of occurrence of intraluminal thrombus, with or without embolism; (2) plaque stabilization and regression; and (3) management of atherogenic risk factors. In patients with ICAD, short-term and long-term anticoagulation (compared with aspirin) has not shown to be beneficial. The current guidelines recommend that aspirin monotherapy, the combination of aspirin and extended release dipyridamole, and clopidogrel monotherapy (rather than oral anticoagulants) are all acceptable options in patients with noncardioembolic ischemic stroke and transient ischemic attack. The findings of another pilot trial suggest that symptomatic ICAD is a dynamic lesion and cilostazol may prevent its progression. Overall, the subgroup analysis from randomized trials, provide evidence about benefit of aggressive atherogenic risk factor management among patients with ICAD. Current guidelines recommend statin therapy with intensive lipid-lowering effects for patients with atherosclerotic ischemic stroke or transient ischemic attack with or without known coronary artery disease to reduce the risk of stroke and cardiovascular events.

Intracranial atherosclerotic disease: an update

The consensus conference on intracranial atherosclerosis provides a comprehensive review of the existing literature relevant to the epidemiology, diagnosis, prevention, and treatment of intracranial atherosclerosis, and identifies principles of management and research priorities. Patients who have suffered a stroke or transient ischemic attack attributed to stenosis (50-99%) of a major intracranial artery face a 12 to 14% risk for subsequent stroke during the 2-year period after the initial ischemic event, despite treatment with antithrombotic medications. The annual risk for subsequent stroke may exceed 20% in high-risk groups. In patients with intracranial atherosclerotic disease, short-term and long-term anticoagulation is not superior to antiplatelet treatment. Overall, the subgroup analyses from randomized trials provide evidence about benefit of aggressive atherogenic risk factor management. Intracranial angioplasty with or without stent placement has evolved as a therapeutic option for patients with symptomatic intracranial atherosclerotic disease, particularly those with high-grade stenosis with recurrent ischemic symptoms, medication failure, or both. A multicenter randomized trial is currently under way to compare stent placement with intense medical management for patients with high-grade symptomatic intracranial atherosclerotic disease.

Human carotid atherosclerotic plaque increases oxidative state of macrophages and low-density lipoproteins, whereas paraoxonase 1 (PON1) decreases such atherogenic effects

Human atherosclerotic plaque contains a variety of oxidized lipids, which can facilitate further oxidation. Paraoxonase 1 (PON1) is a high-density lipoprotein (HDL)-associated esterase (lipolactonase), exhibiting antiatherogenic properties. The aims of the present study were to examine the oxidizing potency of the human carotid plaque lipid extract (LE), and the antiatherogenic role of PON1 on LE oxidation competence. Human carotid plaques were extracted by organic solvent, and the extract was incubated with lipoprotein particles, with macrophages, or with probes sensitive to oxidative stress, with or without preincubation with PON1, followed by oxidative-stress assessment. Our findings imply that the LE oxidized LDL, macrophages, and exogenous probes and decreases HDL-mediated cholesterol efflux from macrophages, in a dose-dependent manner. Incubation of PON1 with LE significantly affects LE composition, reduces LE atherogenic properties, and decreases the extract's total peroxide concentration by 44%, macrophage oxidation by 25%, and probe oxidation by up to 52%. We conclude that these results expand our understanding of how the plaque itself accelerates atherogenesis and provides an important mechanism for attenuation of atherosclerosis development by the antioxidant action of PON1 on the atherosclerotic plaque.

Diagnosis of atherosclerosis by imaging

New and experimental imaging techniques are being developed that will permit better visualization and compositional characterization of atheromatous plaques. This review provides discussion of techniques that are currently used in clinical practice, as well as techniques that are investigational only, including coronary angiography, intravascular ultrasound, computed tomography, magnetic resonance imaging, positron emission tomography, and single-photon emission computed tomography. Types of atheromatous plaque are reviewed, and the value of examining vascular calcification in risk assessment is discussed. Experimental use of these imaging techniques in animal models and in clinical studies will enhance our understanding of the development of plaque and will determine whether these techniques would be useful and practical for predicting disease course. Early detection and identification of the type of plaque that is present may generate novel opportunities for primary prevention through changes in lifestyle or even through drug therapy, especially in patients at high cardiovascular risk.

Up-regulation of reverse cholesterol transport key players and rescue from global inflammation by ApoA-I(Milano)

Recombinant-ApoA-I_M (rApoA-I_M) administration has been shown to regress and stabilize atherosclerotic plaques. However, the mechanisms responsible for these beneficial effects are not fully understood. The aims of the present study were to define whether the benefits of rApoA-I_M treatment were mediated via an enhanced reverse cholesterol transport (RCT) and/or anti-inflammation-related mechanisms. Advanced aortic lesions were induced in New Zealand White rabbits (n= 16). Animals were randomized to placebo or rApoA-I_M (rApoA-I_M/phospholipids; ETC-216), two infusions 4 days apart. Four days after last dose, aortas and livers were processed for cholesterol content, expression of RCT-related receptors (ATP-binding cassette A-1 [ABCA-1] and scavenger receptor BI [SR-BI]), and inflammation-related markers (inducible nitric oxide synthase [iNOS] and capase-3). Oxidative stress was assessed in the vessel wall and in plasma. rApoA-I_M administration resulted in a significant reduction in the hepatic and aortic cholesterol content without differences in plasma levels. This effect was associated with an up-regulation of vessel wall ABCA-1, as well as a hepatic and arterial-wall SR-BI up-regulation. Systemic and atherosclerotic-plaque inflammation markers were significantly reduced by the rApoA-I_M administration, as demonstrated by a reduction in circulating oxidative stress markers and prostaglandin F1-α levels, and the down-regulation of the iNOS and caspase 3 in the aortic lesions. rApoA-IM up-regulated the ABCA-1 and SR-BI levels to a greater extent than the wild-type form of apoA-I in in vitro studies done with lipid-rich macrophages. Our data suggest that rApoA-I_M administration enhances RCT and induces a ‘rescue’ from the global inflammatory status associated with atherosclerotic disease. The Milano form of apoA-I seems to be more efficient in RCT than the apoA-I wild-type.

Hypercoagulability markers in patients with peripheral arterial disease: association to ankle-brachial index

Peripheral arterial disease is diagnosed by measuring the ankle-brachial index. Values lower than 0.90 define the disease being usually related to its severity. Patients with peripheral arterial disease may show a hypercoagulability state. The aim of this study was to assess hemostatic variables and to correlate them with the presence of peripheral arterial disease and its severity as assessed by ankle-brachial index values. Plasma levels of D dimer, plasminogen, prothrombin fragment 1+2, plasminogen activator inhibitor and thrombomodulin were measured in 36 patients with peripheral arterial disease (group 1) and 30 without disease (group 2). Significant differences for D dimer, plasminogen, prothrombin fragment 1+2 and plasminogen activator inhibitor type 1 between the 2 groups were found (P<0.05). Significant and inverse correlations were also observed (Pearson correlation, P<0.05) between ankle-brachial index values and levels of both plasminogen and plasminogen activator inhibitor type 1. Although there was no significant correlation between ankle-brachial index and levels of D dimer, higher D dimer values were observed in patients with lower ankle-brachial index values. The results confirm a trend to hypercoagulability and hypofibrinolysis in patients with peripheral arterial disease. Increased levels of plasminogen activator inhibitor type 1 seem to be associated with the severity of the disease, considering the inverse correlation between this inhibitor and ankle-brachial index.