Association of intracellular pro- and anti-inflammatory cytokines in peripheral blood with the clinical or ultrasound indications for carotid endarterectomy in patients with carotid atherosclerosis

Biomarkers in unstable carotid plaque: Physiopathology and Prediction

AIMS

To study the role of cytokines and vascular inflammatory biomarkers in unstable carotid plaque.

BACKGROUND

Clinical studies showed that not only the degree of stenosis but also the type of carotid plaque can be responsible for ipsilateral ischemic stroke.

OBJECTIVE

The objective of this study is to suggest a role for vulnerable carotid atherosclerotic disease in the occurrence of ischemic stroke.

METHODS

PubMed, Embase, Cochrane library, and reference lists have been used to evaluate articles published until February 15, 2021.

RESULTS

Several factors may be involved in unstable plaque. Clinical studies support the involvement of brain inflammatory biomarkers as well as cytokines in the unstable carotid plaque.

CONCLUSIONS

Biomarkers could help to stratify patients with a vulnerable carotid plaque and to personalize the drug treatment. In this review, we briefly discuss the characteristics of vulnerable plaque and the role of biomarkers in the vulnerable carotid plaque.

Using Serum Biomarkers for Identifying Unstable Carotid Plaque: Update of Current Evidence

Carotid atherosclerosis is responsible for a great proportion of ischemic strokes. Early identification of unstable or vulnerable carotid plaques, and therefore, of patients at high risk for stroke, is of significant medical and socioeconomical value. We reviewed the current literature and discussed the potential role of the most important serum biomarkers in identifying patients with carotid atherosclerosis who are at high risk for atheroembolic stroke.

Inflammation of carotid plaques and risk of cerebrovascular events

Carotid atherosclerotic plaques represent a risk for ischemic stroke. The data indicate that the risk for distal embolization from atherosclerotic lesions in internal carotid arteries is not related only to the degree of stenosis but also to the composition of plaques. The stability of atherosclerotic plaque depends on the thickness of the fibrous cap and plaque hemorrhage. Recent research indicated that the inflammatory activity of atherosclerotic lesions is pivotal in the progression of atherosclerotic plaques. It also promotes the development of unstable atherosclerotic lesions and is related to thromboembolic cerebrovascular complications. Inflammation destabilizes atherosclerotic plaques through the degradation of their fibrotic structure. Inflammation of atherosclerotic plaques was confirmed by histopathologic findings and levels of circulating inflammatory markers which were correlated to the intensity of the inflammation in atherosclerotic lesions. Recently, new techniques like fluorodeoxyglucose positron emission tomography (18-FDG PET) were developed for the identification of inflammation of atherosclerotic lesions in the vessel wall in vivo. Systemic inflammatory markers, particularly interleukins, tumor necrosis factor-alpha and metalloproteinases were shown to be related to the intensity of the inflammatory process in atherosclerotic lesions and the cerebrovascular events. Identification of inflamed atherosclerotic plaques may help to identify unstable atherosclerotic lesions and subjects at high risk for cerebrovascular incidents who need intensive preventive measures including anti-inflammatory medication.

Is Interleukin-38 a key player cytokine in atherosclerosis immune gene therapy?

Atherosclerosis, a chronic inflammatory disease of the arteries associated with lipids and other metabolic alterations is a leading cause of death all around the world and its rate is raising as a result of unhealthy lifestyles. Reports by World Health Organization indicate that 31% of all death occurrences are due to heart attacks and strokes. Today, the most common medicines for treating atherosclerosis are statins which are HMG-coA reductase inhibitors. Beside their benefits in treating atherosclerosis, some side effects have been reported as well. Thus, therapeutic methods based on statins should be evaluated to result in more beneficial effects. Since atherosclerosis is an inflammatory disorder, an anti-inflammatory component can decrease the impact of this disease. Interleukin-38, a newly discovered anti-inflammatory cytokine, which acts as an Interleukin-36 receptor antagonist can block Nuclear Factor KB and Activator protein-1 signaling pathways, and block atherogenic core formation accordingly. This novel proposed immune gene therapy can be applied to atherosclerosis treatment in a trial study. In this hypothesis, Interleukin-38 gene is transferred into bone marrow Mesenchymal Stem Cells of atherosclerotic mouse model Apo E-/- via an adenoviral vector. It is expected that Interleukin-38 gene expression by Mesenchymal Stem Cells can efficiently remedy atherosclerosis without the side effects of statins.

Characteristics of peripheral immune cell subsets in patients with carotid atherosclerosis undergoing carotid endarterectomy

Introduction

The role of circulating immune cells in the pathophysiology of cerebrovascular accidents is currently under debate. The aim of this study was to characterize peripheral immune cell subsets in patients undergoing carotid endarterectomy (CEA).

Material and methods

We conducted a prospective observational study in a group of 124 patients with significant carotid stenosis undergoing carotid endarterectomy, both symptomatic and asymptomatic. We compared the percentages of circulating immune cells: B lymphocytes, T lymphocytes, T helper, cytotoxic T, CD4+/CD8+ ratio, T regulatory, monocytes and NK cells before CEA and 6 h after the procedure.

Results

Total lymphocyte count and cytotoxic T lymphocyte count decreased 6 h after CEA in both subgroups. The NK cell level decrease was statistically significant only in the symptomatic subgroup (19.41 ±9.30 before CEA and 16.52 ±9.37 after CEA; p = 0.0044), but not in the asymptomatic subgroup (17.88 ±9.14 before CEA and 15.91 ±9.51 after CEA; p = 0.0886). The T lymphocyte level showed a statistically significant increase only in symptomatic patients (69.74 ±10.16 before CEA vs. 71.45 ±9.77 after CEA; p = 0.0462), and not in the asymptomatic subgroup (70.08 ±11.19 prior to CEA and 70.21 ±12.35; p = 0.9048). B lymphocyte, helper T lymphocyte and regulatory T (Treg) lymphocyte (CD4+/CD25+) levels showed a significant increase after CEA.

Conclusions

This is the first study to compare circulating immune cells in patients undergoing carotid endarterectomy. Only the symptomatic subgroup experienced a significant decrease in the NK cell level and an increase in the T lymphocyte count after CEA. This study enriches our understanding of immune cell kinetics during carotid endarterectomy.

Decreased PPAR-γ expression after internal carotid artery stenting is associated with vascular lesions induced by smooth muscle cell proliferation and systemic inflammation in a minipig model

Vascular restenosis after stenting is known to be largely mediated by proliferation of vascular smooth muscle cells. Recently, peroxisome proliferator-activated receptor gamma (PPAR-γ) has been implicated as a regulator of cellular inflammatory responses, and the PPAR-γ agonist rosiglitazone (ROSI) has been shown to attenuate atherosclerosis formation. However, whether ROSI can inhibit neointimal formation by regulating the inflammatory response and inhibiting vascular smooth muscle hyperplasia after stenting-induced injury remains to be clarified. Accordingly, in this study, 10 minipigs were randomly divided into two groups: the stenting group (n = 5) and the ROSI group (n = 5). Morphometric analysis was conducted for the stented arteries. The protein expressions of PPAR-γ and smooth muscle 22-alpha (SM22α) were analyzed by immunohistochemistry and western blotting, and the serum interferon-γ and interleukin-10 levels were measured by enzyme-linked immunosorbent assay. Three months after implantation, morphometric analysis revealed that administration of ROSI (0.5 mg/kg/d, continuous administration for 90 days) resulted in significant reductions of luminal stenosis, the neointimal area, and neointimal thickness, as compared to the stenting groups. The expression of PPAR-γ and the PPAR-γ/SM22α ratio in the ROSI group were higher than in the stenting group. Furthermore, the serum interferon-γ and interleukin-10 levels were found to be increased and to reach peak levels at 4 h and 7 days after stenting, respectively, after which both declined. However, ROSI treatment resulted in decreased interferon-γ and increased interleukin-10 levels after stenting. In both groups, the cytokine levels returned to the baseline levels on day 56 after stenting. Taken together, these results suggest that ROSI can reduce neointimal formation after stenting by inhibiting the local and systemic inflammatory responses as well as vascular smooth muscle hyperplasia.

Peripheral Blood Lymphocyte Subsets (CD4+, CD8+ T Cells, NK Cells) in Patients with Cardiovascular and Neurological Complications after Carotid Endarterectomy

Background: The aim of the study was to evaluate the differences in the circulating immune cells’ subgroups after the atherosclerotic plaque removal in patients presenting with postoperative complications as compared to the patients without complications after carotid endarterectomy (CEA). Methods: Patients with significant carotid atherosclerosis (n = 124, age range: 44 to 87 years) who underwent CEA were enrolled in a prospective study. The immunology study using flow cytometry was performed to determine the percentages of peripheral blood T cells (CD4⁺, CD8⁺, Treg—CD4⁺/CD25⁺) and NK (natural killer) cells before and after the procedure. The data were expressed as the percentage of total lymphocytes ± the standard error of mean. Results: The mean percentage of lymphocytes (61.54% ± 17.50% vs. 71.82% ± 9.68%, p = 0.030) and CD4 T lymphocytes (T helper, 38.13% ± 13.78% vs. 48.39% ± 10.24%, p = 0.027) was significantly lower six hours after CEA in patients with postoperative 30-day cardiovascular and neurological complications as compared to the group without complications. On the other hand the mean NK level in the group with complications was significantly higher (21.61% ± 9.00% vs. 15.80% ± 9.31%, p = 0.048). Conclusions: The results of this study suggest that after carotid endarterectomy the percentages of circulating immune cells subsets differ in patients with and without postoperative complications.

Inflammatory markers in patients with internal carotid artery stenosis

INTRODUCTION

Available reports underline the significance of the inflammatory process in the development, progression and destabilisation of atherosclerotic plaques in the internal carotid artery (ICA). The aim of this study was to evaluate the relationship between the degree of ICA stenosis, ultrasound plaque morphology and serum concentration of selected inflammatory markers.

MATERIAL AND METHODS

Sixty-five patients with ICA stenosis > 50% (39 symptomatic) and 30 healthy volunteers were enrolled in the study. Clinical, neurological examination and laboratory evaluation (leucocyte count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen, tumour necrosis factor-α (TNF-α), interleukins (1β, 6 and 10), anti-cytomegalovirus IgG antibody titre) were performed. Stenosis grade ≥ 70%, ulcerations on the plaque surface and a hypoechoic (or predominantly hypoechoic) structure of the plaque, obtained by colour-coded duplex examination, were accepted as the characteristics of unstable stenoses.

RESULTS

Unstable ultrasound features of ICA stenosis were found significantly more often in symptomatic than in asymptomatic patients (71.79% vs. 30.71% for stenosis degree ≥ 70%, p = 0.001 and 61.23% vs. 38.46% for unstable plaque morphology, p = 0.01). Patients with ICA stenosis had significantly higher serum concentrations of interleukin-6, fibrinogen, ESR and higher CRP values than the individuals from the control group (p = 0.001, p = 0.009, p = 0.036, p = 0.009 respectively). Patients with unstable plaques structure had significantly higher concentrations of TNF-α, interleukin-6, fibrinogen, higher number of leukocytes, monocytes and higher CRP values than patients with stable plaques (p = 0.008, p = 0.049, p = 0.012, p = 0.0002, p = 0.006, p = 0.0003 respectively). No significant differences in above-mentioned parameters between the groups with stenosis < 70% and ≥ 70% were found.

CONCLUSIONS

There is a relationship between the activity of the selected inflammatory markers in serum and atherosclerotic unstable internal carotid artery stenosis. There is no relationship between serum concentration of inflammatory markers and degree of carotid artery stenosis.

T lymphocyte autoreactivity in inflammatory mechanisms regulating atherosclerosis

Atherosclerosis has been clearly demonstrated to be a chronic inflammatory disease of the arterial wall. Both cells of the innate and the acquired immune system, particularly monocytes and T lymphocytes, are implicated in the atherogenic process, producing different cytokines with pro- and anti-inflammatory effects. The majority of pathogenic T cells involved in atherosclerosis are of the Th1 profile, that has been correlated positively with coronary artery disease. Many studies conducted to evaluate the molecular factors responsible for the activation of T cells have demonstrated that the main antigenic targets in atherosclerosis are modified endogenous structures. These self-molecules activate autoimmune reactions mainly characterized by the production of Th1 cytokines, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper we will summarize the different T-cell subsets involved in atherosclerosis and the best characterized autoantigens involved in cardiovascular inflammation.

Cellular and molecular players in the atherosclerotic plaque progression

Atherosclerosis initiation and progression is controlled by inflammatory molecular and cellular mediators. Cells of innate immunity, stimulated by various endogenous molecules that have undergone a transformation following an oxidative stress or nonenzymatic glycation processes, activate cells of the adaptive immunity, found at the borders of atheromas. In this way, an immune response against endogenous modified antigens takes place and gives rise to chronic low-level inflammation leading to the slow development of complex atherosclerotic plaques. These lesions will occasionally ulcerate, thus ending with fatal clinical events. Plaque macrophages represent the majority of leukocytes in the atherosclerotic lesions, and their secretory activity, including proinflammatory cytokines and matrix-degrading proteases, may be related to the fragilization of the fibrous cap and then to the rupture of the plaque. A considerable amount of work is currently focused on the identification of locally released proinflammatory factors that influence the evolution of the plaque to an unstable phenotype. A better understanding of these molecular processes may contribute to new treatment strategies. Mediators released by the immune system and associated with the development of carotid atherosclerosis are discussed.

Inflammatory responses induced by fluoride and arsenic at toxic concentration in rabbit aorta

Epidemiological and experimental studies have demonstrated the atherogenic effects of environmental toxicant arsenic and fluoride. Inflammatory mechanism plays an important role in the pathogenesis of atherosclerosis. The aim of the present study is to determine the effect of chronic exposure to arsenic and fluoride alone or combined on inflammatory response in rabbit aorta. We analyzed the expression of genes involved in leukocyte adhesion [P-selectin (P-sel) and vascular cell adhesion molecule-1(VCAM-1)], recruitment and transendothelial migration of leukocyte [interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1)] and those involved in pro-inflammatory cytokines [interleukin-6 (IL-6)]. We found that fluoride and arsenic alone or combined increased the expression of VCAM-1, P-sel, MCP-1, IL-8, and IL-6 at the RNA and protein levels. The gene expressions of inflammatory-related molecules were attenuated when co-exposure to the two toxicants compared with just one of them. We also examined the lipid profile of rabbits exposed to fluoride and (or) arsenic. The results showed that fluoride slightly increased the serum lipids but arsenic decreased serum triglyceride. We showed that inflammatory responses but not lipid metabolic disorder may play a crucial role in the mechanism of the cardiovascular toxicity of arsenic and fluoride.

Current role of biomarkers in carotid disease: a systematic review

BACKGROUND AND PURPOSE

Accumulating evidence suggests that carotid plaque vulnerability can be used as a determinant of ischemic stroke risk stratification and carotid intervention. Novel markers of high-risk carotid plaque in patients are needed.

SUMMARY OF REVIEW

Advances in cellular and molecular pathophysiology, the demand for accurately predicting carotid risk, and choosing the optimal prevention strategy are stimulating great interest in the development of novel surrogate markers. Biomarkers in cardiovascular disease are expected to predict the natural history, clinical outcomes, and the efficacy of disease-modifying interventions. We aimed to review the literature regarding clinical data on novel serum biomarkers related to ischemic cerebrovascular events associated with carotid artery disease. We provide background information on the biomarkers related to all aspects of carotid disease: natural history, carotid intervention strategies for symptomatic and asymptomatic patients, perioperative risk prediction, and their therapeutic implications.

CONCLUSION

At present, heterogeneous data support evidence that biological markers can help existing practices to more accurately assess patients at risk for stroke. Randomized-controlled trials for carotid artery disease and carotid intervention, incorporating biomarkers, are needed.

Multiple aberrations in shared inflammatory and oxidative & nitrosative stress (IO&NS) pathways explain the co-association of depression and cardiovascular disorder (CVD), and the increased risk for CVD and due mortality in depressed patients

There is evidence that there is a bidirectional relationship between major depression and cardiovascular disorder (CVD): depressed patients are a population at risk for increased cardiac morbidity and mortality, and depression is more frequent in patients who suffer from CVD. There is also evidence that inflammatory and oxidative and nitrosative stress (IO&NS) pathways underpin the common pathophysiology of both CVD and major depression. Activation of these pathways may increase risk for both disorders and contribute to shared risk. The shared IO&NS pathways that may contribute to CVD and depression comprise the following: increased levels of pro-inflammatory cytokines, like interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-γ; T cell activation; increased acute phase proteins, like C-reactive protein, haptoglobin, fibrinogen and α1-antitrypsin; complement factors; increased LPS load through bacterial translocation and subsequent gut-derived inflammation; induction of indoleamine 2,3-dioxygenase with increased levels of tryptophan catabolites; decreased levels of antioxidants, like coenzyme Q10, zinc, vitamin E, glutathione and glutathione peroxidase; increased O&NS characterized by oxidative damage to low density lipoprotein (LDL) and phospholipid inositol, increased malondialdehyde, and damage to DNA and mitochondria; increased nitrosative stress; and decreased ω3 polyunsaturated fatty acids (PUFAs). The complex interplay between the abovementioned IO&NS pathways in depression results in pro-atherogenic effects and should be regarded as a risk factor to future clinical CVD and due mortality. We suggest that major depression should be added as a risk factor to the Charlson "comorbidity" index. It is advised that patients with (sub)chronic or recurrent major depression should routinely be assessed by serology tests to predict if they have an increased risk to cardiovascular disorders.

An update on markers of carotid atherosclerosis in patients with Type 2 diabetes

Carotid atherosclerosis constitutes an important cause of ischemic brain attack and stroke, accounting for up to 40% of cases of ischemic cerebrovascular disease. Type 2 diabetes mellitus is an independent risk factor for stroke and its recurrence. Thus, identifying diabetic patients who are at high risk of developing stroke is of great clinical importance. Noninvasive measurements of surrogate markers of atherosclerosis, such as novel serum biomarkers, can be helpful in detecting subclinical carotid disease, especially among individuals at the highest cardio-/cerebro-vascular risk. Previous studies have proposed an expanding body of serum biomarkers, such as C-reactive protein, fibrinogen, adipokines, cytokines and growth factors, as novel indicators of carotid atherosclerosis development that predict carotid-related clinical outcomes. Furthermore, those biomarkers are expected to assess the efficacy of both pharmaceutical and interventional strategies. Accordingly, it is increasingly clear that measuring biomarkers may improve the definition of cerebrovascular risk profile in patients with Type 2 diabetes mellitus.

Beta2-Glycoprotein I is a Target of T Cell Reactivity in Patients with Advanced Carotid Atherosclerotic Plaques

Evidence in animal models that beta2-glycoprotein I (β2GPI), the principal target of autoimmune antiphospholipid antibodies, is involved in the initiation and progression of atherosclerosis, prompted us to investigate the possible role of this self protein as a target autoantigen of immune reactions in patients with carotid atherosclerosis. Plaque-infiltrating T lymphocytes from patients, and circulating T lymphocytes from patients and healthy subjects were tested by cell proliferation assay and by flow cytometry for intracellular cytokine expression in response to β2GPI. ELISA was used to detect cytokine production in culture supernatants and anti-β2GPI/anti-cardiolipin antibodies in serum samples. Eight of 35 PBMC samples and 1 of 5 plaque-infiltrating T lymphocyte samples from patients proliferated in response to β2GPI, whereas PBMC from healthy subjects did not. Patients' PBMC samples that proliferated in response to β2GPI produced significantly higher IFN-γ and TNF-α than non-proliferating PBMC. β2GPI-specific plaque-derived T lymphocytes expressed IFN-γ, TNF-α and IL-4, suggesting concomitant Th1 and Th2 activation. Only one patient's serum was positive for anti-β2GPI and anti-cardiolipin IgM antibodies. These new findings indicate that β2GPI induces a cellular immune response in a subpopulation of patients with carotid atherosclerosis thus contributing to the inflammatory responses involved in carotid atherosclerotic disease.

The effect of statin therapy on the progression of carotid artery stenosis in relation to stenosis severity

OBJECTIVES

To examine the effect of early statin treatment on progression of arteriosclerosis in internal carotid arteries (ICA); to compare the progression of arteriosclerosis in ICA of patients treated with a statin to the progression seen in drug-naïve patients.

PATIENTS AND METHODS

We performed repetitive Doppler scans of 363 carotid arteries with ICA stenosis > or =40% in 254 patients over time. Information on statin therapy and other risk factors for stroke were correlated with the annual change in degree of ICA stenosis.

RESULTS

In statin-treated patients, 19% of ICA stenosis showed a progression while 74% showed a regression of stenosis. In statin-naïve patients, 63% of stenotic arteries showed a progression, while a reduction could be observed in 28%. Decrease of ICA stenosis was most accentuated in patients with a mild stenosis and was independent of serum cholesterol levels.

CONCLUSION

Treatment with statins already in early stages of ICA stenosis might delay the progression and even reverse the degree of stenosis.

Socioeconomic position and inflammatory and immune biomarkers of cardiovascular disease: applications to the Panel Study of Income Dynamics

Biomarkers are an important aspect of research linking psychosocial stress and health. This article aims to characterize the biological pathways that may mediate the relationship between socioeconomic position (SEP) and cardiovascular disease (CVD) and address opportunities for further research within the Panel Study of Income Dynamics (PSID), with a focus on psychosocial stressors related to SEP. We review the literature on CVD biomarkers, including adhesion and proinflammatory molecules (interleukin-6, other cytokines, C-reactive proteins, fibrinogen, etc.) and microbial pathogens. The impact of socioeconomic determinants and related psychosocial stressors on CVD biomarkers mediated by behavioral and central nervous system pathways are described. We also address measurement and feasibility issues, including specimen collection methods, processing and storage procedures, laboratory error, and within-person variability. In conclusion, we suggest that PSID consider adding important assessments of specific CVD biomarkers and mediating behavioral measures, health, and medications that will ultimately address many of the gaps in the literature regarding the relationship between SEP and cardiovascular health.

The autonomic nervous system and ischemic stroke: a reciprocal interdependence

Signs and symptoms of autonomic nervous system (ANS) dysfunction are frequently reported after ischemic or haemorrhagic stroke and in many cases they exhibit peculiar patterns in relationship with the site and the extension of brain lesion. However if an ANS disorder can cause or predispose to a stroke is far from being correctly known. Evidences in favor of a pathogenetic mechanism of an ANS dysfunction are reported for myocardial infarction and such data are likely to be appropriate also for atherothrombotic type of ischemic stroke. On the other hand, it is well known that many risk factors for this pathology are strongly correlated with an altered functioning of ANS so that a reciprocal interdependence between ANS and stroke can be hypothesized. This review points to evidence the possible relationship existing between these two conditions and suggests a quite different diagnostic and therapeutic approach to both on the basis of their pathogenetic mechanisms.