Detecting vulnerable plaque using peripheral blood: inflammatory and cellular markers

Nitric oxide pretreatment enhances atheroma component highlighting in vivo with intercellular adhesion molecule-1-targeted echogenic liposomes

We present an ultrasound technique for the detection of inflammatory changes in developing atheromas. We used contrast-enhanced ultrasound imaging with (i) microbubbles targeted to intercellular adhesion molecule-1 (ICAM-1), a molecule of adhesion involved in inflammatory processes in lesions of atheromas in New Zealand White rabbits, and (ii) pretreatment with nitric oxide-loaded microbubbles and ultrasound activation at the site of the endothelium to enhance the permeability of the arterial wall and the penetration of ICAM-1-targeted microbubbles. This procedure increases acoustic enhancement 1.2-fold. Pretreatment with nitric oxide-loaded echogenic liposomes and ultrasound activation can potentially facilitate the subsequent penetration of targeted echogenic liposomes into the arterial wall, thus allowing improved detection of inflammatory changes in developing atheromas.

Acute phase reactants as novel predictors of cardiovascular disease

Acute phase reaction is a systemic response which usually follows a physiological condition that takes place in the beginning of an inflammatory process. This physiological change usually lasts 1-2 days. However, the systemic acute phase response usually lasts longer. The aim of this systemic response is to restore homeostasis. These events are accompanied by upregulation of some proteins (positive acute phase reactants) and downregulation of others (negative acute phase reactants) during inflammatory reactions. Cardiovascular diseases are accompanied by the elevation of several positive acute phase reactants such as C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, white blood cell count, secretory nonpancreatic phospholipase 2-II (sPLA2-II), ferritin, and ceruloplasmin. Cardiovascular disease is also accompanied by the reduction of negative acute phase reactants such as albumin, transferrin, transthyretin, retinol-binding protein, antithrombin, and transcortin. In this paper, we will be discussing the biological activity and diagnostic and prognostic values of acute phase reactants with cardiovascular importance. The potential therapeutic targets of these reactants will be also discussed.

Evaluation of recombinant endostatin in the treatment of atherosclerotic plaques and neovascularization in rabbits

OBJECTIVE

Atherosclerotic plaques and neovascularization play an important role in the course of coronary atherosclerosis. This study evaluated the effect of recombinant endostatin on experimental atherosclerotic plaques and neovascularization in rabbits.

METHODS

Eighteen healthy male rabbits were divided into three groups: control group, atherosclerotic model group, and recombinant endostatin treated group. The atherosclerotic model was established via a high-cholesterol diet after balloon catheter injury. The subject weights, serum total cholesterol, creatine kinase-myocardial band fraction (CKMB), and matrix metalloproteinase-2 (MMP-2) were measured. Six weeks after treatment, the aortic roots were taken for pathological assay. The thickness ratio of the intima to media was measured by hematoxylin and eosin (HE) staining, and the number of neovessels was measured by immunohistochemistry via monoclonal antibody CD31 staining.

RESULTS

The weight, plasma total cholesterol, and CKMB were not significantly different between the atherosclerotic model group and the recombinant endostatin treated group, but much higher than those of the control group (P<0.05). The thickness ratio of the intima to media in the recombinant endostatin treated group was distinctly less than that in the atherosclerotic model group (P<0.05). The number of neovessels decreased dramatically (P<0.05) and the content of MMP-2 decreased slightly without statistical difference (P>0.05) in the recombinant endostatin treated group, compared to the atherosclerotic model group.

CONCLUSIONS

Recombinant endostatin is able to inhibit the growth of neovascularization in the atherosclerotic plaque and the development of plaque.

Clinical application of blood biomarkers in cerebrovascular disease

Identifying a biomarker or panel of biomarkers of cerebral ischemia would have a major impact on the care of stroke patients by facilitating early management decisions and individualization of care. Biochemical surrogates of cerebral ischemia might also play an important role by identifying relevant pathways for novel therapeutic strategies and by facilitating early clinical trials in cerebrovascular disease. Serum biomarkers related to pathways of hemostasis, oxidation and inflammation, or alterations in glial and neuronal proteins, have been identified but none have been recommended for routine clinical use. This review describes the most promising biomarkers of cerebrovascular disease and the context and limitations in which they have been studied.

Delivery of stem cells to porcine arterial wall with echogenic liposomes conjugated to antibodies against CD34 and intercellular adhesion molecule-1

In atherosclerosis, the loss of vascular stem cells via apoptosis impairs the capacity of the vascular wall to repair or regenerate the tissue damaged by atherogenic factors. Recruitment of exogenous stem cells to the plaque tissue may repopulate vascular cells and help repair the arterial tissue. Ultrasound-enhanced liposomal targeting may provide a feasible method for stem cell delivery into atheroma. Bifunctional echogenic immunoliposomes (BF-ELIP) were generated by covalently coupling two antibodies to liposomes; the first one specific for CD34 antigens on the surface of stem cells and the second directed against the intercellular adhesion molecule-1 (ICAM-1) antigens on the inflammatory endothelium covering atheroma. CD34+ stem cells from adult bone marrow were incubated on the ICAM-1-expressing endothelium of the aorta of swine fed high cholesterol diets, which was preloaded with BF-ELIP. Significantly increased stem cell adherence and penetration were detected in particular in the aortic segments treated with 1 MHz low-amplitude continuous wave ultrasound. Fluorescence and scanning electron microscopy confirmed the presence of BF-ELIP-bound CD34+ cells in the intimal compartment of the atheromatous arterial wall. Ultrasound treatment increased the number of endothelial cell progenitors migrating into the intima. Thus, under ultrasound enhancement, BF-ELIP bound CD34+ stem cells selectively bind to the ICAM-1 expressing endothelium of atherosclerotic lesions.

Inflammatory markers: linking unstable plaques to coronary event, an interventional perspective

Abundant data links inflammatory mechanisms to atheromatous plaque destabilization leading to plaque rupture and coronary events. The discovery of inflammatory cells and inflammatory mediators within atherosclerotic plaques prone to rupture led to a series of studies demonstrating an association between various markers of inflammation and future coronary events. Inflammatory markers have also been used in patients undergoing coronary angioplasty in an attempt to predict restenosis and risk for post-procedural coronary events. This review article provides an overview on the potential use of inflammatory markers in the context of coronary interventions.

Interleukin-3 is elevated in patients with coronary artery disease and predicts restenosis after percutaneous coronary intervention

BACKGROUND

Interleukin-3 (IL-3) synthesized by activated T-lymphocytes is a mediator in chronic inflammation and is suspected to promote atherosclerosis. Since there is no data on IL-3 in patients with coronary artery disease (CAD) available, we compared IL-3 concentrations in different subsets of patients with CAD to healthy control patients.

METHODS

205 consecutive patients with CAD, 136 with stable angina and 69 with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention, 61 patients with asymptomatic CAD and 41 patients with normal coronary arteries were investigated. Serum concentrations of IL-3 and hs-CRP were assessed at baseline and after 6 weeks, 6, and 12 months.

RESULTS

In patients undergoing coronary angioplasty, IL-3 was detectable more frequently than in those with asymptomatic CAD or without CAD, 21 vs. 8%, p=0.02, and 21 vs. 1%, p<0.001, respectively. Patients undergoing coronary angioplasty who developed symptomatic restenosis more frequently had detectable IL-3 levels than patients without restenosis, 45 vs. 17%, p=0.02. IL-3 was the only independent predictor for restenosis in a multivariate analysis. Hs-CRP was significantly elevated in patients with ACS, 230+/-170 mg/l vs. 100+/-140 mg/l, p=0.02, but did not correlate with IL-3 concentrations at any time.

CONCLUSION

IL-3, an important regulator of chronic inflammation, is elevated in patients with CAD, particularly in symptomatic patients undergoing percutaneous coronary intervention. Furthermore, high IL-3 concentrations were found to be predictive of symptomatic restenosis.

Imaging and molecular biomarkers of vulnerable atheromatous plaques

Rupture of a vulnerable atherosclerotic plaque is the main cause of acute coronary syndromes, myocardial infarction and death. Identification of biomarkers that accurately predict the risk of plaque rupture may be a means to establish and monitor response to therapeutic intervention. This review focuses on recent advances for the use of circulating molecular biomarkers and imaging modalities to assess atherosclerotic vulnerable plaques in both preclinical models and clinical conditions.

Clinical implications of vulnerable plaque

In many individuals, the first indicator of atherosclerosis is an acute heart attack, which is often fatal. Despite innovations in medical therapy and interventional cardiology techniques, coronary artery disease continues to be the leading cause of death in the USA. There is great interest in identifying vulnerable plaques and vulnerable patients as a possible means to stem the tide against coronary artery disease. Improvements in diagnostic studies and development of novel imaging tools have opened the possibilities for significant advances in the management of vulnerable plaque. The result of improved risk stratification, by both noninvasive and invasive means, will be a better assessment of the risk/benefit relationships for the novel therapies that are needed to further reduce the morbidity and mortality of the disease. Correct identification of vulnerable plaque would permit the use of more effective systemic treatment and enable clinical trials to study the supplemental benefit from local treatments.

Management of Vertebral Stenosis Complicated by Presence of Acute Thrombus

A 44-year-old male presented with multiple punctate acute infarcts of the vertebrobasilar circulation and a computed tomographic angiogram showing stenosis of the right vertebral origin. A digital subtraction angiogram demonstrated a new intraluminal filling defect at the origin of the stenotic vertebral artery where antegrade flow was maintained. This filling defect was accepted to be an acute thrombus of the vertebral origin, most likely due to rupture of a vulnerable plaque. The patient was treated with intravenous heparin. A control angiogram revealed dissolution of the acute thrombus under anticoagulation and the patient was treated with stenting with distal protection. Diffusion-weighted magnetic resonance imaging demonstrated no additional acute ischemic lesions. We were unable to find a similar report in the English literature documenting successful management of an acute vertebral ostial thrombus with anticoagulation. Anticoagulation might be considered prior to endovascular treatment of symptomatic vertebral stenoses complicated by the presence of acute thrombus.

From vulnerable plaque to vulnerable patient--Part III: Executive summary of the Screening for Heart Attack Prevention and Education (SHAPE) Task Force report

Screening for early-stage asymptomatic cancers (eg, cancers of breast and colon) to prevent late-stage malignancies has been widely accepted. However, although atherosclerotic cardiovascular disease (eg, heart attack and stroke) accounts for more death and disability than all cancers combined, there are no national screening guidelines for asymptomatic (subclinical) atherosclerosis, and there is no government- or healthcare-sponsored reimbursement for atherosclerosis screening. Part I and Part II of this consensus statement elaborated on new discoveries in the field of atherosclerosis that led to the concept of the "vulnerable patient." These landmark discoveries, along with new diagnostic and therapeutic options, have set the stage for the next step: translation of this knowledge into a new practice of preventive cardiology. The identification and treatment of the vulnerable patient are the focuses of this consensus statement. In this report, the Screening for Heart Attack Prevention and Education (SHAPE) Task Force presents a new practice guideline for cardiovascular screening in the asymptomatic at-risk population. In summary, the SHAPE Guideline calls for noninvasive screening of all asymptomatic men 45-75 years of age and asymptomatic women 55-75 years of age (except those defined as very low risk) to detect and treat those with subclinical atherosclerosis. A variety of screening tests are available, and the cost-effectiveness of their use in a comprehensive strategy must be validated. Some of these screening tests, such as measurement of coronary artery calcification by computed tomography scanning and carotid artery intima-media thickness and plaque by ultrasonography, have been available longer than others and are capable of providing direct evidence for the presence and extent of atherosclerosis. Both of these imaging methods provide prognostic information of proven value regarding the future risk of heart attack and stroke. Careful and responsible implementation of these tests as part of a comprehensive risk assessment and reduction approach is warranted and outlined by this report. Other tests for the detection of atherosclerosis and abnormal arterial structure and function, such as magnetic resonance imaging of the great arteries, studies of small and large artery stiffness, and assessment of systemic endothelial dysfunction, are emerging and must be further validated. The screening results (severity of subclinical arterial disease) combined with risk factor assessment are used for risk stratification to identify the vulnerable patient and initiate appropriate therapy. The higher the risk, the more vulnerable an individual is to a near-term adverse event. Because <10% of the population who test positive for atherosclerosis will experience a near-term event, additional risk stratification based on reliable markers of disease activity is needed and is expected to further focus the search for the vulnerable patient in the future. All individuals with asymptomatic atherosclerosis should be counseled and treated to prevent progression to overt clinical disease. The aggressiveness of the treatment should be proportional to the level of risk. Individuals with no evidence of subclinical disease may be reassured of the low risk of a future near-term event, yet encouraged to adhere to a healthy lifestyle and maintain appropriate risk factor levels. Early heart attack care education is urged for all individuals with a positive test for atherosclerosis. The SHAPE Task Force reinforces existing guidelines for the screening and treatment of risk factors in younger populations. Cardiovascular healthcare professionals and policymakers are urged to adopt the SHAPE proposal and its attendant cost-effectiveness as a new strategy to contain the epidemic of atherosclerotic cardiovascular disease and the rising cost of therapies associated with this epidemic.

Aerobic exercise, but not flexibility/resistance exercise, reduces serum IL-18, CRP, and IL-6 independent of beta-blockers, BMI, and psychosocial factors in older adults

Increased serum levels of inflammatory mediators have been associated with numerous disease states including atherosclerosis, Type II diabetes, hypertension, depression, and overall mortality. We hypothesized that a long-term exercise intervention among older adults would reduce serum inflammatory cytokines, and this reduction would be mediated, in part, by improvements in psychosocial factors and/or by beta-adrenergic receptor mechanisms. Adults age 64 were randomly assigned to either an aerobic exercise treatment (CARDIO) or a flexibility/strength exercise treatment (FLEX) 3 days/week, 45 min/day for 10 months. A subgroup of subjects treated with non-selective beta(1)beta(2) adrenergic antagonists were included to evaluate the potential role of beta-adrenergic receptor adaptations as mediators of an exercise-induced change in inflammation. The inflammatory mediators [C-reactive protein (CRP), IL-6, tumor necrosis factor (TNF)-alpha, and IL-18] and the psychosocial factors (depression, perceived stress, optimism, sense of coherence, and social support) were measured pre- and post-intervention. The CARDIO treatment resulted in significant reductions in serum CRP, IL-6, and IL-18 compared to the FLEX treatment (significant treatment x time interaction, p<.05), whereas TNFalpha declined in both groups (main effect of time, p=.001). However, several psychosocial factors (depression, optimism, and sense of coherence) improved in both groups suggesting that the reduction of CRP, IL-6, and IL-18 in the CARDIO group was not mediated by improvements in psychosocial scores. With respect to the potential role of beta-adrenergic receptors, both CARDIO subjects treated with beta-adrenergic antagonists and those who were not treated with those medications demonstrated similar reductions in serum CRP, IL-6, IL-18, and TNFalpha. In summary, we have observed that an aerobic exercise intervention can significantly reduce serum inflammatory mediators, but beta-adrenergic receptors and psychosocial factors do not appear to be involved.

Early lens aging is accelerated in subjects with a high risk of ischemic heart disease: an epidemiologic study

BACKGROUND

Ischemic heart disease (IHD) is one of the most important causes of mortality and morbidity in the Western world. There is a relationship between aging of the lens of the human eye and cardiovascular disease. The present study was conducted to examine if the risk of ischemic heart disease could be estimated by fluorophotometric assessment of lens aging.

METHODS

A total of 421 subjects were included. Risk of IHD was estimated from non-ocular data using the Precard software. Lens aging was quantified by lens fluorometry.

RESULTS

The risk of IHD was strongly related to lens fluorophore accumulation (p = 0.001). The relationship between IHD and lens aging was attributable to tobacco smoking and dysglycemia.

CONCLUSION

The risk of ischemic heart disease related to smoking and diabetes mellitus can be estimated using the aging of the lens of the eye as a biomarker for generalized tissue-damage.

Effect of obesity on the relationship between plasma C-reactive protein and coronary artery stenosis in patients with stable angina

INTRODUCTION

The association between plasma C-reactive protein (CRP) and the extent of coronary artery disease (CAD) in patients with stable angina remains controversial. Obesity is strongly associated with elevated CRP levels, potentially confounding the relationship between CRP and CAD severity.

METHODS AND RESULTS

We studied 830 subjects without CAD and 218 patients with CAD undergoing elective coronary angiography. Geometric means of CRP were computed in a two-way analysis of covariance model in which study participants were stratified into nine groups according to CAD status (no CAD, single-vessel disease or multivessel disease) and tertiles of BMI. There was a significant interaction between CAD and categories of BMI with regard to CRP level (P=0.002). In the lower tertile of BMI, patients with CAD had markedly higher CRP concentration compared to control subjects (1.16, 1.80 and 2.82 mg/L in subjects without CAD, patients with single-vessel disease and patients with multivessel disease, respectively; P=0.003). However, the relationship between CRP and CAD became weaker for patients in the second BMI tertile (P=0.15), whereas no significant relationship was observed for patients in the third BMI tertile (P=0.75). In patients undergoing coronary angioplasty (n=195), BMI was independently related to the magnitude of the angioplasty-induced CRP elevations (P=0.002).

CONCLUSION

The level of obesity is essential to the interpretation of the relationship between CRP and severity of CAD. The production of inflammatory mediators with increasing levels of obesity becomes the dominant determinant of plasma CRP levels and masks the vascular contribution due to CAD.

Association of inflammatory marker and highly sensitive C-reactive protein with aerobic exercise capacity, maximum oxygen uptake and insulin resistance in healthy middle-aged volunteers

BACKGROUND

Increased levels of inflammation markers, such as C-reactive protein (CRP) and tumor necrosis factor-alpha , have been found in insulin resistance syndrome. Those with elevated levels of high-sensitive CRP (hs-CRP) are at a higher risk for coronary heart disease. In the present study, we evaluated whether maximum oxygen uptake and insulin resistance are related to hs-CRP for the primary prevention of coronary heart disease.

METHODS AND RESULTS

The subjects were 50 subjects who did not have diabetes mellitus. A multi-step treadmill exercise test was performed to obtain the maximum oxygen uptake when assessed by computerized breath-by-breath analysis. As an index of insulin resistance, the homeostasis model insulin resistance index (HOMA-R; fasting glucose x fasting insulin/405) was used. In addition, bodyweight, body mass index, subcutaneous fat thickness, total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride were measured. Multivariate analysis revealed that hs-CRP was significantly correlated with HDL-cholesterol, uric acid, gamma-glutamyl transpeptidase and maximum oxygen uptake. The maximum oxygen uptake showed the smallest odds ratio was in terms of the relationship with hs-CRP.

CONCLUSIONS

The present study suggests that the development of exercising habits increases the maximum oxygen uptake. Furthermore, an elevated maximum oxygen uptake decreases HOMA-R and reduces the inflammatory marker CRP, suggesting that exercising habit plays an important role in the primary prevention of coronary heart disease.

Statin, like aspirin, should be given as early as possible in patients with acute coronary syndrome

It is estimated that about 1 million patients are hospitalized for acute coronary events each years in the United States. An acceptable theory is that the acute coronary syndrome is caused by rupture of the atherosclerotic plaque with superimposed thrombus, which is a complex process and involving a number of different stages. Previous studies indicated that inflammation is one of the most important features of vulnerable plaque, and occurs in most vulnerable plaque, comprised of monocytes, macrophages, and lymphocytes in both the cap and in the adventitia. This is supported by evidence that reduction in serum inflammatory marker levels, such as C-reactive protein, significantly decreased coronary events in patients with acute coronary syndrome. A large number of investigations have demonstrated that administration of statin could modify C-reactive protein concentrations with a concurrent fall in cardiovascular events. Our recent data indicated that reduction of inflammatory markers could be achieved within 24 h following a single dose of statin administration after admission in patients with coronary artery disease. Based on the available evidence and in light of the new understanding that statins have pleiotropic effects, especially as a potent anti-inflammatory agent, the statins, like aspirin, should be clinically given as early as possible in patients with acute coronary syndrome.

Early experience in the application of distal protection devices in treatment of peripheral vascular disease of the lower extremities

The objectives of this study were to reduce the risk of showering distal vessels with thromboemboli created during percutaneous interventions of the arteries in the lower extremities. Distal protection devices have been used in coronary and carotid interventions. Hence, using similar techniques, these filters and occlusion balloons were advanced past the targeted lesions and distally into femoral and popliteal arteries. Once opened, these devices allowed standard angioplasty and stent placement and captured the dislodged thromboemboli. Five cases were performed with the distal protection devices. One case used the distal occlusion balloon and four with the filter system. All five passed the lesion and were deployed. All five devices were retrieved without incident and were retrieved with substantial debris. There were no adverse events. The use of distal protection to treat high-risk or unstable lesions in the lower extremities shows great promise. Further case will be needed to evaluate the device for feasibility and safety.

Coronary artery spatial distribution of acute myocardial infarction occlusions

BACKGROUND

Acute coronary occlusions leading to ST-segment elevation myocardial infarctions (STEMIs) are due primarily to rupture of atherosclerotic plaques. Present "vulnerable plaque" detection technology focuses on identifying individual plaques with no clear therapeutic plan beyond conventional risk factor reduction. We developed a spatial map of the distribution of acute coronary occlusions to test our hypothesis that plaque ruptures do not occur uniformly throughout the coronary tree.

METHODS AND RESULTS

We analyzed 208 consecutive patients who presented to the Brigham and Women's Hospital with STEMI and mapped the location of the acute coronary occlusion. These occlusions were not uniformly distributed throughout each of the major epicardial coronary arteries but tended to cluster within the proximal third of each of the vessels (right coronary artery, P=0.001; left anterior descending artery, P=0.003; left circumflex artery, P=0.001). Furthermore, Poisson regression showed that for each 10-mm increase in distance from the ostium, the risk of an acute coronary occlusion was significantly decreased by 13% in the right coronary artery, 30% in the left anterior descending artery, and 26% in the left circumflex artery.

CONCLUSIONS

Acute coronary occlusions leading to STEMI tend to cluster in predictable "hot spots" within the proximal third of the coronary arteries. Identification of these high-risk zones for acute coronary occlusions will lead to future advances in vulnerable plaque detection technology and potentially locally directed preventive strategies.

The −174G/C polymorphism of IL-6 is useful to screen old subjects at risk for atherosclerosis or to reach successful ageing

High levels of IL-6 are coupled with impaired immune efficiency, morbidity and mortality in ageing. Elderly men with GG (C-) genotype in -174 locus of IL-6 promoter are disadvantaged for longevity due to higher IL-6 than CG or CC (C+) carriers. As IL-6 increases in atherosclerosis, the study of the polymorphism of IL-6 may be a useful tool in identifying old subjects at risk for atherosclerosis. Thus, we divided old men into C+ and C- genotypes. Natural killer (NK) cell cytotoxicity, IL-6, IL-10, TNF-alpha, MTmRNA and zinc ion bioavailability were also evaluated and compared with nonagenarians and old patients affected by carotid stenosis. Old C- patients display, other than elevated IL-6, higher IL-10, TNF-alpha and MTmRNA coupled with impaired NK cell cytotoxicity and lower zinc ion bioavailability than C+ patients. The same trend is observed in old subjects with C- phenotype. Nonagenarians with C+ genotype show less inflammation, low MTmRNA, satisfactory NK cell cytotoxicity and good zinc bioavailability than long-living individuals with C- genotype. A higher degree of bilateral carotid stenosis is observed in C- patients than in C+ patients (88 vs 52%). Therefore, C- genotype is coupled with chronic inflammation, impaired immune efficiency, low zinc ion bioavailability and high MTmRNA. As such, C- genotype is a risk factor for the appearance of severe atherosclerosis. Thus, the polymorphism of IL-6, together with the analysis of zinc turnover and immune parameters, is of a great clinical relevance in order to genetically identify old subjects at risk in developing severe atherosclerosis and, at the same time, to predict subjects predestined to successful ageing. As a consequence, more convenient therapies may be prepared for a complete recovery.