The Discovery of the Pathophysiological Aspects of Atherosclerosis — A Review

Hyperoside Nanomicelles Alleviate Atherosclerosis by Modulating the Lipid Profile and Intestinal Flora Structure in High-Fat-Diet-Fed Apolipoprotein-E-Deficient Mice

Atherosclerosis (AS) is a serious threat to human health and the main pathological basis of cardiovascular disease. Hyperoside (Hyp), a flavonoid found mainly in traditional Chinese herbs, can exert antitumor, anti-inflammatory, antioxidant, and cardiovascular-protective effects. Herein, we prepared hybrid nanomicelles (HFT) comprising Hyp loaded into pluronic F-127 and polyethylene glycol 1000 vitamin E succinate and assessed their effects on AS. To establish an AS model, apolipoprotein-E-deficient (ApoE^-/-) mice were fed a high-fat diet. We then analyzed the effects of HFT on AS-induced changes in aortic tissues and metabolic markers, simultaneously assessing changes in gut flora community structure. In mice with AS, HFT significantly reduced the aortic plaque area; decreased levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, inflammatory factors, and inducible nitric oxide synthase (NOS); increased high-density lipoprotein cholesterol, endothelial NOS, superoxide dismutase, catalase, and glutathione levels; and promoted the proliferation of beneficial gut bacteria. HFT could regulate intestinal flora structure and lipid metabolism and inhibit inflammatory responses. These beneficial effects may be mediated by inhibiting nuclear factor kappa B signal activation, reducing inflammatory factor expression and improving gut microflora structure and dyslipidemia. The present study provides an empirical basis for the development and clinical application of new dosage forms of Hyp.

Atherosclerosis: Known and unknown

Atherosclerotic disease, such as myocardial infarction and stroke, is the number one killer worldwide. Atherosclerosis is considered to be caused by multiple factors, including genetic and environmental factors. In humans, it takes several decades until the clinical complications develop. There are many known risk factors for atherosclerosis, including hypercholesterolemia, hypertension, diabetes and smoking, which are involved in the pathogenesis of atherosclerosis; however, it is generally believed that atherosclerosis is vascular chronic inflammation initiated by interactions of these risk factors and arterial wall cells. In the past 30 years, the molecular mechanisms underlying the pathogenesis of atherosclerosis have been investigated extensively using genetically modified animals, and lipid-reducing drugs, such as statins, have been demonstrated as the most effective for the prevention and treatment of atherosclerosis. However, despite this progress, questions regarding the pathogenesis of atherosclerosis remain and there is a need to develop new animal models and novel therapeutics to treat patients who cannot be effectively treated by statins. In this review, we will focus on two topics of atherosclerosis, "pathology" and "pathogenesis," and discuss unanswered questions.

High iliac calcium score is associated with increased severity and complexity of peripheral arterial disease and predicts global atherosclerotic burden

BACKGROUND

The role of vascular calcifications in iliac arteries for predicting global atherosclerotic burden in still unknown. The aim of this study was to investigate whether iliac calcium score (ICS), a new computed tomographic angiography (CTA) derived biomarker of vascular calcification, can predict the severity and complexity of peripheral arterial disease (PAD) as well as the global atherosclerotic burden.

PATIENTS AND METHODS

This was a single centre, non-randomized, observational prospective study on 84 consecutive patients with symptomatic peripheral arterial disease, undergoing peripheral CTA examination of the lower limbs, divided into high (n = 42) and low ICS (n = 42) groups with a median value for ICS of 3934 HU.

RESULTS

Patients with high ICS were significantly older (66.2 ± 8.0 vs. 62.8 ± 11.2, p < 0.0001) and were more frequently diabetic (61.9 vs. 38.1 %, p = 0.04). ICS was significantly higher in patients with Rutherford stage 5-6 vs. 1-2 (p = 0.03) and in TASC D or TASC C vs. TASC B class (p = 0.01). Mean iliac intima-media thickness (i-IMT) was significantly higher in the high ICS group compared to the low ICS group (1.3 ± 0.2 vs. 0.9 ± 0.2, p < 0.0001). Linear regression analysis demonstrated a very good correlation between ICS and i-IMT (r = 0.59, p < 0.0001 for right, r = 0.57, p < 0.0001 for left and r = 0.67, p < 0.0001 for both iliac arteries averaged). Patients with high ICS presented a significantly lower left ventricular ejection fraction compared to those with low ICS (45.3 ± 4.3 vs. 53.8 ± 4.8, p < 0.0001). Linear regression analysis demonstrated significant inverse correlation between ICS and left ventricular EF (r = -0.54, p < 0.0001).

CONCLUSIONS

Increased values of ICS, a new CTA marker of vascular calcification, are associated with a higher severity and complexity of PAD and a more depressed left ventricular function. High ICS values are also associated with increased i-IMT. Both can represent new surrogate markers of an increased atherosclerotic burden.

Relationship between Urinary Level of Phytate and Valvular Calcification in an Elderly Population: A Cross-Sectional Study

Pathological calcification generally consists of the formation of solid deposits of hydroxyapatite (calcium phosphate) in soft tissues. Supersaturation is the thermodynamic driving force for crystallization, so it is believed that higher blood levels of calcium and phosphate increase the risk of cardiovascular calcification. However several factors can promote or inhibit the natural process of pathological calcification. This cross-sectional study evaluated the relationship between physiological levels of urinary phytate and heart valve calcification in a population of elderly out subjects. A population of 188 elderly subjects (mean age: 68 years) was studied. Valve calcification was measured by echocardiography. Phytate determination was performed from a urine sample and data on blood chemistry, end-systolic volume, concomitant diseases, cardiovascular risk factors, medication usage and food were obtained. The study population was classified in three tertiles according to level of urinary phytate: low (<0.610 μM), intermediate (0.61-1.21 μM), and high (>1.21 μM). Subjects with higher levels of urinary phytate had less mitral annulus calcification and were less likely to have diabetes and hypercholesterolemia. In the multivariate analysis, age, serum phosphorous, leukocytes total count and urinary phytate excretion appeared as independent factors predictive of presence of mitral annulus calcification. There was an inverse correlation between urinary phytate content and mitral annulus calcification in our population of elderly out subjects. These results suggest that consumption of phytate-rich foods may help to prevent cardiovascular calcification evolution.

Hippocrates: the forefather of neurology

Hippocrates is one of the most influential medical doctors of all times. He started observing and experimenting in times of mysticism and magic. He carried a holistic and humanitarian approach to the patient with examination as the principal approach-inspection, palpation and auscultation are still the most important tools in diagnosing algorithms of today. He had immense experience with the human body most likely due to numerous wound treatments he had performed; some even believe he performed autopsies despite the negative trend at the time. Hippocrates identified the brain as the analyst of the outside world, the interpreter of consciousness and the center of intelligence and willpower. Interestingly, Hippocrates was aware of many valid concepts in neurology; his treatise On the Sacred Disease was the most important for understanding neurology and epilepsy. His other ideas pioneered modern day neurology mentioning neurological diseases like apoplexy, spondylitis, hemiplegia, and paraplegia. Today, 10 % of neurological Pubmed and 7 % of neuroscience Scopus reviews mention Corpus Hippocraticum as one of the sources. Therefore, Hippocrates may be considered as the forefather of neurology.

Mathematical modelling of atheroma plaque formation and development in coronary arteries

Atherosclerosis is a vascular disease caused by inflammation of the arterial wall, which results in the accumulation of low-density lipoprotein (LDL) cholesterol, monocytes, macrophages and fat-laden foam cells at the place of the inflammation. This process is commonly referred to as plaque formation. The evolution of the atherosclerosis disease, and in particular the influence of wall shear stress on the growth of atherosclerotic plaques, is still a poorly understood phenomenon. This work presents a mathematical model to reproduce atheroma plaque growth in coronary arteries. This model uses the Navier-Stokes equations and Darcy's law for fluid dynamics, convection-diffusion-reaction equations for modelling the mass balance in the lumen and intima, and the Kedem-Katchalsky equations for the interfacial coupling at membranes, i.e. endothelium. The volume flux and the solute flux across the interface between the fluid and the porous domains are governed by a three-pore model. The main species and substances which play a role in early atherosclerosis development have been considered in the model, i.e. LDL, oxidized LDL, monocytes, macrophages, foam cells, smooth muscle cells, cytokines and collagen. Furthermore, experimental data taken from the literature have been used in order to physiologically determine model parameters. The mathematical model has been implemented in a representative axisymmetric geometrical coronary artery model. The results show that the mathematical model is able to qualitatively capture the atheroma plaque development observed in the intima layer.

Does microcalcification increase the risk of rupture?

Rupture of atherosclerotic plaque, which is related to maximal stress conditions in the plaque among others, is a major cause of mortality. More careful examination of stress distributions in atherosclerotic plaques reports that it could be due to local stress behaviors at critical sites caused by cap thinning, inflammation, macroscopic heterogeneity, and recently, the presence of microcalcifications. However, the role of microcalcifications is not yet fully understood, and most finite element models of blood vessels with atheroma plaque ignore the heterogeneity of the plaque constituents at the microscale. The goal of this work is to investigate the effect of microcalcifications on the stress field of an atheroma plaque vessel section. This is achieved by performing a parametric finite element study, assuming a plane strain hypothesis, of a coronary artery section with eccentric atheroma plaque and one microcalcification incorporated. The geometrical parameters used to define and design the idealized coronary plaque anatomy and the microcalcification were the fibrous cap thickness and the microcalcification ratio, angle and eccentricity. We could conclude that microcalcifications should be considered in the modeling of this kind of problems since they cause a significant alteration of the vulnerable risk by increasing the maximum maximal principal stress up to 32%, although this increase of stress is not uniform (12% on average). The obtained results show that the fibrous cap thickness, the microcalcification ratio and the microcalcification eccentricity, in combination with the microcalcification angle, appear to be the key morphological parameters that play a determinant role in the maximal principal stress and accordingly in the rupture risk of the plaque.

Hyperglycaemia exerts deleterious effects on late endothelial progenitor cell secretion actions

Endothelial progenitor cells (EPCs) play a fundamental role in tissue regeneration and vascular repair both by differentiating into endothelial cells and by secretion of vasoactive substances that promote angiogenesis and maintain vascular homeostasis. It has previously been shown that hyperglycaemia impairs early and late EPC functions, such as differentiation, proliferation and adhesion. However, its role in the regulation of the production of vasoactive substances in EPCs, especially in late EPCs, is less well defined. We investigated the effects of hyperglycaemia on the production of vasodilator, fibrinolytic and angiogenic growth factors, and also on the activity of superoxide dismutase (SOD) in late EPCs. For this purpose, late EPCs were incubated with different concentrations of D-glucose (5-40 mmol/L) for 24 hr. Levels of nitric oxide (NO), tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), prostaglandin I(2) (PGI(2)), vascular endothelial growth factor (VEGF) and the activity of SOD were measured by enzyme-linked immunosorbent assay (ELISA). Under high glucose stress conditions, late EPCs exhibited lower levels of NO, t-PA, PAI-1, PGI(2) and VEGF compared to control medium (5 mmol/L glucose). Moreover, high glucose was also observed to decrease the activity of SOD in late EPCs. These results suggest that hyperglycaemia-induced impairment of late EPC secretion functions could contribute to the development of vascular disease in diabetes.

Advanced glycation end products impair the migration, adhesion and secretion potentials of late endothelial progenitor cells

Background

Endothelial progenitor cells (EPCs), especially late EPCs, play a critical role in endothelial maintenance and repair, and postnatal vasculogenesis. Advanced glycation end products (AGEs) have been shown to impair EPC functions, such as proliferation, migration and adhesion. However, their role in the regulation of the production of vasoactive substances in late EPCs is less well defined.

Methods

Passages of 3~5 EPCs, namely late EPCs, were cultured with different concentrations (0~500 μg/ml) of AGEs, and the apoptosis, adhesion and migration were subsequently determined. The release of vasoactive substances, such as stromal cell-derived factor-1 (SDF-1), nitric oxide (NO), prostaglandin I₂ (PGI₂), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA), and in addition the activity of superoxide dismutase (SOD), were evaluated by ELISA. At the same time, the gene and protein expressions of CXCR4 were assayed by real-time RT-PCR and western-blot.

Results

AGEs promoted late EPC apoptosis. Moreover, AGEs impaired late EPC migration and adhesion in a concentration-dependent manner. Accordingly, the production of SDF-1 was decreased by AGEs. Although the CXCR4 expressions of late EPCs were up-regulated for AGE concentrations of 50, 100 or 200 μg/ml, a marked decrease was observed for the higher concentration of 500 μg/ml. Furthermore, co-culturing with AGEs decreased the levels of NO, t-PA, PGI_2, and the activity of SOD but up-regulated the production of PAI-1.

Conclusion

Our data provide evidence that AGEs play an important role in impairing late EPC functions, which could contribute to the development of vascular diseases in diabetes.

The Pathogenesis, Analysis, and Imaging Methods of Atherosclerotic Disease of the Carotid Artery: Review of the Literature

Cerebrovascular (CVA) accidents are the second leading cause of death worldwide and their numbers are increasing. Strokes can arise from several causes, with extracranial carotid artery atherosclerosis (CAS) being one of the leading causes. CAS causes these strokes either by diminishing blood flow distal to the diseased stenotic segment of the artery or, as more recently discovered, by a thromboembolic event of material from the plaque site itself. The specific etiology of CAS is unknown, but causative factors in the formation of atherosclerotic plaque of the carotid arteries have been linked to specific morphological areas within the plaque that may be vulnerable to rupture, leading to thromboemboli into the cerebrovascular circulation. The current means for imaging and reporting CAS is through the measurement of the severity of luminal diameter stenosis caused by atherosclerotic disease. Recent developments in medical imaging techniques have expanded the role of early imaging and detection of CAS. Although current practice uses luminal narrowing as the surrogate marker to assess CAS, it has been recently discovered that plaque morphology and composition may help predict the clinical behavior of CAS and better determine the necessary medical intervention or risk of stroke. Although a single optimized imaging modality for standard CAS imaging has not been established or agreed on, various modalities can provide key elements to a successful exam. This review article will evaluate the most commonly used methods for CAS imaging along with the new and upcoming uses, advantages, and limitations for advanced CAS imaging.

Detection of altered extracellular matrix in surface layers of unstable carotid plaque: an optical spectroscopy, birefringence and microarray genetic analysis

Erosion and rupture of surface layers in atherosclerotic plaque can cause heart attack and stroke; however, changes in luminal surface composition are incompletely defined. Laser-induced fluorescence spectroscopy (LIFS), with limited tissue penetration, was used to investigate the surface of unstable carotid plaque and correlated with microscopy, birefringence and gene expression. Arterial matrix collagens I, III and elastin were assessed in unstable plaques (n = 25) and reference left internal mammary arteries (LIMA, n = 10). LIFS in addition to selective histological staining with picrosirius red, Movat pentachrome and immunostaining revealed decreased elastin and increased collagen I and III (P < 0.05) in carotid plaque when compared with LIMA. Within plaque, collagen I was elevated in the internal carotid region versus the common carotid region. Polarized light microscopy detected layers of aligned collagen and associated mechanical rigidity of the fibrous cap. Microarray analysis of three carotid and three LIMA specimens confirmed up-regulation of collagen I, III and IV, lysyl oxidase and MMP-12. In conclusion, LIFS analysis coupled with microscopy revealed marked regional differences in collagen I, III and elastin in surface layers of carotid plaque; indicative of plaque instability. Birefringence measurements demonstrated mechanical rigidity and weakening of the fibrous cap with complementary changes in ECM gene expression.

Aortic atheroma and adverse cerebral outcome: risk, diagnosis, and management options

Aortic atheromatous disease is a common finding in the patient presenting for cardiac surgery. Adverse neurologic outcome has been closely linked to the extent of aortic atherosclerosis. In order to optimize perioperative outcomes, the location and severity of disease needs accurate characterization using multimodal techniques. Although various preoperative radiographic techniques have variably identified patients with significant atheroma, intraoperative echocardiographic imaging has proven most useful in localizing and characterizing the degree of aortic atheroma. Epiaortic assessment of the ascending aorta has been utilized in guiding surgical modifications and interventions aimed at reducing the risk of neurologic injury. Although no particular technique has been definitely studied, avoidance of the identifiable atheromatous aortic region has been a main feature of the various modifications employed to optimize neurologic outcome after cardiac surgery.

Peculiarities of cell composition and cell proliferation in different type atherosclerotic lesions in carotid and coronary arteries

Increased cell proliferation in early atherosclerotic lesions is recognized as an essential event in atherogenesis but the levels of cell proliferation in the different stages of atherosclerotic plague formation in different types of human large arteries are still insufficiently studied. In the present work, we studied intima thickness and proliferation of newly "infiltrated" hematogenous and resident cells in atherosclerotic lesions of the carotid and coronary arteries and compared these parameters with those in the aorta, which we reported in an earlier publication (Orekhov et al. [8]). Analysis of intima thickness and proliferation in grossly unaffected intima and in different types of atherosclerotic lesions (initial lesions, fatty streaks, lipofibrous plaques, and fibrous plaques) revealed that, although there were similar tendencies in the change of the infiltration levels of hematogenous cells and proliferation in different types of arteries, there were significant quantitative differences between different types of arteries. Hematogenous cells in lipofibrous plaques of the coronary and carotid arteries were found to account for a third and almost for a half of the total cell population, respectively, while atherosclerotic lesions in the aorta, as shown by us previously, contain no more than 15% of hematogenous cells. This suggests that the contribution of hematogenous cells to the development of atherosclerosis in the carotid and coronary arteries appears to be more significant than in the aorta. Despite the differences in the numbers of accumulating hematogenous cells in the intima, a similar "bell-shaped" dependence of cell numbers on the lesion type, involved the following sequence: unaffected intima--initial lesions--fatty streaks--lipofibrous plaques--fibrous plaques, was detected in the coronary and carotid arteries. The visualization of PCNA-positive cells in atherosclerotic and unaffected zones of the coronary and carotid arteries revealed similar patterns of the distribution of proliferating cells. The maximum numbers of PCNA-positive resident cells were identified in lipofibrous plaques. The changes in the total cell numbers were found to be accompanied by the changes in the numbers of both proliferating resident cells and proliferating hematogenous cells. According to our knowledge, this is the first report that provides factual data about the similarities and differences in cell composition and proliferation between different types of large arteries in which the development of atherosclerosis is of crucial importance.

Past, current and future concepts in atherosclerotic biobanking

Knowledge on the pathogenesis of atherosclerotic disease mainly originates from observations made by pathologists who systemically collected vascular tissue. Biobanking of human tissues has become a professionalized joint effort, including the expertise of epidemiologists, pathologists and biologists. Mostly, biobanks are used for cross-sectional studies and the obtained specimens often represent later stages of disease. Technical improvements in high-throughput genetic and proteomic screening lead to important new insights into pathophysiological processes. Atherosclerotic disease progression is a major killer in the Western society. Pathological biobanking studies revealed insights in plaque progression and destabilization. However, atherosclerotic disease is a typical example where insights into progression of the disease may be hampered by the cross-sectional design of the biobanks. This article will focus on the accomplishments that have been made through biobanking of atherosclerotic tissues in the past and the present. In addition, future potentials of atherosclerotic plaque biobanks will be discussed.

Cadmium and cardiovascular diseases: cell biology, pathophysiology, and epidemiological relevance

Today cardiovascular diseases (CVDs) are the killer number one world wide. In 2004 an estimated 17.1 million people died due to CVDs and this number will further increase to an estimated 23.6 million by 2030. Importantly, currently known risk factors, like hypertension, and hypercholesterolemia, can only be made responsible for about 50-75% of all CVDs, highlighting the urgent need to search for and define new CVD risk factors. Cadmium (Cd) was shown to have the potential to serve as one such novel risk factor, as it was demonstrated-in vitro, in animal studies, and in human studies-that Cd causes atherosclerosis (the basis of most CVDs). Herein, we discuss the molecular and cellular biological effects of Cd in the cardiovascular system; we present concepts on the pathophysiology of Cd-caused atherosclerosis, and provide data that indicate an epidemiological relevance of Cd as a risk factor for CVDs.

Expression and location of intracellular tissue factor in atherosclerosis stable plaque of ApoE(-/-) mice

In the ApoE(-/-) mouse model of atherosclerosis (AS) stable plaque, the expression and location of intracellular tissue factor (TF) in the cellular components of AS stable plaque were investigated in order to explore the cellular mechanism of AS thrombosis. Pathological changes of the stable plaque were observed under a microscope. The expression of TF protein was examined in aortic stable plaque of mice by using immunohistochemistry. Color image planimetric system was used to analyze the histological components of the stable plaque and the TF distribution. Under the confocal microscope, the intracellular TF location in the stable plaque of mice was observed. The results showed the cellular area was the major part of stable plaque (67.36%+/-6.52%, P<0.01). The percentage of total area occupied by cellular area was significantly larger than atheromatous gruel and acellular area (P<0.01). Macrophages and smooth muscle cells (SMC) were major cells in the cellular area. The percentage of total area occupied by SMC was significantly larger than by macrophages (P<0.01). Multiple linear regression analysis showed there was a positive correlation between TF area and SMC area (r=0.616, P=0.008), and no correlation was found between TF area and macrophage area (r=0.437, P=0.08). Pictures of color image planimetric analysis of TF and SMC were merged to highlight areas with co-localization (yellow), it was concluded that the process could be a cell-mediated TF expression in the stable plaque. SMC may be the major source of TF in AS without plaque rupture.

Relationship between ultrasonic attenuation, size and axial strain parameters for ex vivo atherosclerotic carotid plaque

Many ultrasonic parameters, primarily related to attenuation and scatterer size, have been used to characterize the composition of atherosclerotic plaque tissue. In this study, we combine elastographic (axial strain ratio) and ultrasonic tissue characterization parameters, namely the attenuation coefficient and a scattering parameter associated with an "equivalent" scatterer size to delineate between fibrous, calcified, and lipidic plaque tissue. We present results obtained from 44 ex vivo atherosclerotic plaque specimens obtained after carotid endarterectomy on human patients. Our results in the frequency range 2.5 - 7.5 MHz indicate that softer plaques (with higher values of the strain ratio) are usually associated with larger equivalent scatterer size estimates (200 - 500 microm) and lower values of the attenuation coefficient slope (<1 dB/cm/MHz). On the other hand, stiffer plaques (with lower strain ratio values) are associated with smaller equivalent scatterer size estimates (100 - 200 microm) and higher values of the attenuation coefficient slope (1 - 3 dB/cm/MHz). These results indicate that ultrasonic tissue characterization and strain parameters have the potential to differentiate between different plaque types. These parameters can be estimated from radio-frequency data acquired under in vivo conditions and may help the clinician decide on appropriate interventional techniques.

Monocyte-macrophage system as a target for estrogen and selective estrogen receptor modulators

Postmenopausal decline of estrogen production is associated with development of several degenerative disorders such as osteoporosis, neuroinflammatory diseases and vascular wall degeneration. These are associated with the activation of the cells of the monocyte-macrophage system in a context-dependent manner. Estrogen regulates differentiation, maturation and function of many cell types in this system directly or indirectly via other cells by autocrine/paracrine mechanisms. Estrogen effects on the monocyte-macrophage system are primarily repressive. Most of these effects are mediated by repression of expression of genes for cytokines or modulation of other inflammatory mediators by the estrogen receptor (ER)-dependent or nongenomic pathways. The ER-dependent mechanisms mostly involve modulation of the nuclear factor kappa B (NF-kappaB) pathway for transcriptional regulation of cytokine or other mediator genes. In the context of hormone-regulated cancer, estrogen can influence production of cytokines or other inflammatory mediators by both tumor cells and tumor-invading macrophages. The interactions of breast and prostate cancer cells with tumor-associated macrophages (TAMs) may play an important role in tumor progression and even in the development of resistance to hormonal treatment. Regulation of the monocyte-macrophage system by estrogen and cross-talk between the ER and cytokine-mediated pathways provides multiple novel targets for development of selective ER modulator (SERM) molecules for prevention and treatment of postmenopausal degenerative and neoplastic diseases.

Quantitative assessment of the atherosclerotic burden of the aorta by combined FDG-PET and CT image analysis: a new concept

INTRODUCTION

Our objective was to develop a technique for quantifying the extent of atherosclerosis in the aorta by combining standard uptake values (SUVs) in the aortic wall with volumetric data provided by computed tomography (CT).

METHODS

Eighteen patients who had both 18-fluorodeoxyglucose (FDG)-positron emission tomography (PET) and contrast-enhanced CT of the chest and abdomen were selected. All had homogeneous diffuse FDG wall uptake in four segments of the aorta. We divided the patients into three groups according to their age and measured FDG uptake in all four segments of the aorta by calculating the mean SUV for each segment. On each axial CT image, region-of-interest tracings along the inner and outer wall contours of the aorta were generated. The inner surface area was subtracted from the outer surface area. The net area values for each segment were subsequently multiplied by slice thickness to calculate arterial wall volume. By multiplying SUV with wall volume, we were able to calculate the atherosclerotic burden (AB) for each segment of the aorta. We compared the aortic wall volumes, SUVs and AB values in each arterial segment for each age group.

RESULTS

In each aortic wall segment, AB values, SUVs and wall volumes increased with age (P<.05).

CONCLUSION

AB can be used as an indicator of the extent of the atherosclerotic process in the aorta through the use of both metabolic and morphologic data provided by FDG-PET and CT, respectively. This may allow for the optimal screening, diagnosis and management of patients with this common and potentially lethal disorder.

Statin inhibition of Fc receptor-mediated phagocytosis by macrophages is modulated by cell activation and cholesterol

OBJECTIVES

An inflammatory response to altered lipoproteins that accumulate in the arterial wall is a major component of the pathogenesis of atherosclerosis. Statins reduce plasma levels of low-density lipoprotein (LDL) and are effective treatments for atherosclerosis. It is hypothesized that they also modulate inflammation. The aim of this study was to examine whether lovastatin inhibits macrophage inflammatory processes and clarify its mechanism of action.

METHODS AND RESULTS

We examined the effects of statins on phagocytosis of antibody-coated red blood cells by cultured human monocytes and mouse peritoneal macrophages. Lovastatin, simvastatin, and zaragozic acid, a squalene synthase inhibitor, blocked Fc receptor-mediated phagocytosis by cultured human monocytes and mouse peritoneal macrophages. The inhibitory effect of lovastatin on Fc receptor-mediated phagocytosis was prevented completely by addition of mevalonate, farnesyl pyrophosphate, LDL, or cholesterol to the culture medium. The inhibitory effect of zaragozic acid was reversed by addition of LDL, but not by the addition of geranylgeranyl pyrophosphate, to the medium. In addition, the effect of lovastatin on phagocytosis is a function of cell activation because treatment of cells with tumor necrosis factor-alpha or lipopolysaccharide prevented inhibition of phagocytosis by lovastatin.

CONCLUSIONS

The inhibition of Fc receptor-mediated phagocytosis of lovastatin is related to its effect on cholesterol biosynthesis rather than its effect on the formation of isoprenoids.

Emergence of the concept of cardiovascular disease

Historically, the concept of cardiovascular disease is a recent and evolving concept. Well into the eighteenth century, cardiac and vascular diseases were little known and considered a rarity. Description of the circulation by William Harvey (1578-1657) in 1628 marks the beginning of the changes that ensued. However, knowledge was slow to accrue and not until the nineteenth century was the heart taken as a specific object of study. The description of end-stage kidney disease by Richard Bright (1789-1858) in 1827 launched studies of the vasculature, which were to lead to the recognition of hypertension and subsequent identification of the lesions of arteriosclerosis (1833) and atherosclerosis (1904) as diseases of the vasculature. Only between the two world wars did the full impact of these lesions on mortality and morbidity come to be finally recognized. Their study and therapy has defined much of the profound changes that affected twentieth century medicine.

A CCR2-V64I polymorphism affects stability of CCR2A isoform

OBJECTIVE

A valine to isoleucine substitution at position 64 of CCR2 (CCR2-64I) is associated with a delay in progression to AIDS in HIV-1-infected individuals. The aim of the present study is to elucidate the molecular mechanism underlying the effect of this allele.

DESIGN

We analysed the effect of the 64I substitution on levels of expression of CCR2A and CCR2B, two CCR2 isoforms produced by alternative splicing.

METHODS

Sendai virus vector was used to express CCR2 molecules.

RESULTS

While CCR2B trafficked well to the cell surface, CCR2A, which differs from CCR2B only by the sequence of its C-terminal cytoplasmic tail, was detected predominantly in the cytoplasm. The level of expression of CCR2A-64I was significantly higher than that of CCR2A without the substitution. On the other hand, the 64I substitution did not affect levels of CCR2B expression. Pulse-chase experiments revealed that the 64I substitution increased the half-life of CCR2A in cells. When co-expressed with CCR5, CCR2A-64I interfered more severely with cell surface expression of CCR5 than did wild-type CCR2A. Furthermore, immunoprecipitation experiments showed that CCR2A co-precipitated with an immature form of CCR5.

CONCLUSION

These results suggest that CCR2A binds to CCR5 in the cytoplasm and down-modulates its surface expression. We propose that the increased ability of CCR2A-64I to down-modulate CCR5 expression might be a possible cause of a delay in HIV-1 disease progression in patients with this allele.

Calcification of the branches of the external carotid artery detected by panoramic radiography: a case report

Atherosclerosis, a progressive inflammatory disease, may lead to stroke, coronary artery disease, or peripheral artery disease. The prevalence of atherosclerosis associated with morbidity and mortality is very high in industrialized countries. This report describes the case of a 49-year-old male patient whose panoramic radiograph taken as part of a dental examination showed calcification in the branches of the external carotid artery. The right facial artery and left maxillary, facial, and lingual arteries were also calcified. The patient had a history of thrombosis in the right axillary and brachial veins with extension to half of the brachiocephalic trunk. In addition, selective lesions were found in the aorta and mitral valve. The patient's medical history also included hypertriglyceridemia, essential arterial hypertonia, terminal renal insufficiency, renal anemia, neurogen disturbance micturition, secondary hyperparathyroidism, hyperuricemia, lymphatic edema, polyneuropathy, tachyarrhythmia absoluta, and erysipelas. The case presented reports on the possibility of detecting signs of atherosclerosis in arteries of the maxillofacial region by use of panoramic radiography.