Expression of alpha2-macroglobulin, neutrophil elastase, and interleukin-1alpha differs in early-stage and late-stage atherosclerotic lesions in the arteries of the circle of Willis

Serum sortilin as a predictor of stroke in patients with intermediate carotid artery stenosis

BACKGROUND

Sortilin was an important molecular protein involved in the pathogenesis of atherosclerosis. Besides, serum sortilin was associated with adverse cerebrovascular events. Atherosclerotic stenosis in the carotid artery is a major etiology for ischemic stroke. The risk of stroke in patients with intermediate carotid artery stenosis (CAS) was unknown. Hence, the aim of the present study was to evaluate the relationship between serum sortilin levels and stroke in patients with intermediate CAS.

METHODS

A total of 195 intermediate CAS patients were included in this cross-sectional study. The patients were divided into two groups as symptomatic (N = 95) and asymptomatic (N = 100) patients. Patients with a transient ischemic attack (TIA), retinal ischemic event, or ischemic stroke resulting from the narrowed carotid artery were considered to be symptomatic. Serum sortilin concentrations were measured using the enzyme-linked immunosorbent assay.

RESULTS

Serum sortilin level was significantly higher in the symptomatic group than in the severe asymptomatic group (1.53 ± 0.25 ng/mL vs 1.34 ± 0.19 ng/mL, p < 0.001). Besides, high serum sortilin levels (odds ratio = 4.91, 95% confidence intervals 1.24-19.51, p = 0.023) were identified as independent predictors of symptomatic carotid plaque. In the receiver operating characteristic curve analysis, serum sortilin levels higher than 1.34 ng/mL predicted stroke/TIA with a sensitivity of 66.3% and a specificity of 67% (AUC = 0.725, p < 0.001).

CONCLUSIONS

Serum sortilin level is increased in the presence of symptomatic intermediate CAS and may have clinical value in the management of patients with carotid artery disease.

The Impact of Cytokines in Coronary Atherosclerotic Plaque: Current Therapeutic Approaches

Coronary atherosclerosis is a chronic pathological process that involves inflammation together with endothelial dysfunction and lipoprotein dysregulation. Experimental studies during the past decades have established the role of inflammatory cytokines in coronary artery disease, namely interleukins (ILs), tumor necrosis factor (TNF)-α, interferon-γ, and chemokines. Moreover, their value as biomarkers in disease development and progression further enhance the validity of this interaction. Recently, cytokine-targeted treatment approaches have emerged as potential tools in the management of atherosclerotic disease. IL-1β, based on the results of the CANTOS trial, remains the most validated option in reducing the residual cardiovascular risk. Along the same line, colchicine was also proven efficacious in preventing major adverse cardiovascular events in large clinical trials of patients with acute and chronic coronary syndrome. Other commercially available agents targeting IL-6 (tocilizumab), TNF-α (etanercept, adalimumab, infliximab), or IL-1 receptor antagonist (anakinra) have mostly been assessed in the setting of other inflammatory diseases and further testing in atherosclerosis is required. In the future, potential targeting of the NLRP3 inflammasome, anti-inflammatory IL-10, or atherogenic chemokines could represent appealing options, provided that patient safety is proven to be of no concern.

Neutrophils as emerging protagonists and targets in chronic inflammatory diseases

INTRODUCTION

Neutrophils are the key cells of our innate immune system with a primary role in host defense. They rapidly arrive at the site of infection and display a range of effector functions including phagocytosis, degranulation, and NETosis to eliminate the invading pathogens. However, in recent years, studies focusing on neutrophil biology have revealed the highly adaptable nature and versatile functions of these cells which extend beyond host defense. Neutrophils are now referred to as powerful mediators of chronic inflammation. In several chronic inflammatory diseases, their untoward actions, such as immense infiltration, hyper-activation, dysregulation of effector functions, and extended survival, eventually contribute to disease pathogenesis. Therefore, a better understanding of neutrophils and their effector functions in prevalent chronic diseases will not only shed light on their role in disease pathogenesis but will also reveal them as novel therapeutic targets.

METHODS

We performed a computer-based online search using the databases, PubMed.gov and Clinical trials.gov for published research and review articles.

RESULTS AND CONCLUSIONS

This review provides an assessment of neutrophils and their crucial involvement in various chronic inflammatory disorders ranging from respiratory, neurodegenerative, autoimmune, and cardiovascular diseases. In addition, we also discuss the therapeutic approach for targeting neutrophils in disease settings that will pave the way forward for future research.

Association of Neutrophil to Lymphocyte Ratio With Plaque Rupture in Acute Coronary Syndrome Patients With Only Intermediate Coronary Artery Lesions Assessed by Optical Coherence Tomography

Objectives

Plaque vulnerability and rupture rather than plaque size are the major cause of clinical events in patients with intermediate coronary lesions. Therefore, the present study was aimed to explore potential markers associated with plaque rupture in acute coronary syndrome (ACS) patients with intermediate coronary lesions.

Methods

A total of 82 ACS patients presenting with only intermediate coronary lesions (40–70% stenosis demonstrated by quantitative coronary angiography) and no severe stenosis in other main coronary arteries [median age 63 years, 53 male and 29 female] were enrolled. Plaque morphology were assessed by optical coherence tomography (OCT). Hematological indices were assayed by automated hematological analyzer.

Results

Plaque rupture was identified in 14 patients by OCT. Neutrophil to lymphocyte ratio (NLR) in patients with plaque rupture (n = 14) was significantly higher than that in patients with non-plaque rupture (n = 68) [3.85 (3.28, 4.77) vs. 2.13 (1.40, 2.81), p < 0.001]. Multivariate logistic regression analysis revealed that NLR was one of the independent risk factors for plaque rupture in intermediate coronary artery lesions (odds ratio 1.64, 95% confidence intervals 1.18–2.29, p = 0.003). ROC curve analysis found a cutoff point of NLR > 2.94 for plaque rupture with 93.8% sensitivity and 77.9% specificity.

Conclusion

NLR, an inflammatory biomarker, is closely associated with plaque rupture in intermediate coronary artery lesions. Monitoring NLR may be useful in risk stratification and management for intermediate coronary artery lesions.

Increased Pro-Thrombotic Platelet Activity Associated with Thrombin/PAR1-Dependent Pathway Disorder in Patients with Secondary Progressive Multiple Sclerosis

Epidemiological studies confirm the high risk of ischemic events in multiple sclerosis (MS) that are associated with increased pro-thrombotic activity of blood platelets. The most potent physiological platelet agonist is thrombin, which activates platelets via cleavage of specific protease-activated receptors (PARs). Our current study is aimed to determine the potential genetics and proteomic abnormalities of PAR1 in both platelets and megakaryocytes, which may have thromboembolic consequences in the course of MS. The obtained results were correlated with the expression level of platelet and megakaryocyte transcripts for APOA1 and A2M genes encoding atherosclerosis biomarkers: apolipoprotein A1 (ApoA1) and α-2-macroglobulin (α2M), respectively. Moreover, PAR1 functionality in MS platelets was assessed by flow cytometry, determining the level of platelet–platelet and platelet–leukocyte aggregates, platelet microparticles and surface expression of P-selectin. As a PAR1 agonist, the synthetic TRAP-6 peptide was used, which made it possible to achieve platelet activation in whole blood without triggering clotting. Comparative analyses showed an elevated level of platelet activation markers in the blood of MS patients compared to controls. The mRNA expression of gene coding α2M was upregulated, whilst ApoA1 was down-regulated, both in platelets and megakaryocytes from MS patients. Furthermore, we observed an increase in both mRNA expression and surface density of PAR1 in platelets and megakaryocytes in MS compared to controls. Both the level of platelet activation markers and PAR1 expression showed a high correlation with the expression of transcripts for APOA1 and A2M genes.

Challenges and opportunities in stroke genetics

Stroke, ischaemic stroke and subtypes of ischaemic stroke display substantial heritability. When compared with related vascular conditions, the number of established risk loci reaching genome-wide significance for association with stroke is still in the lower range, particularly for aetiological stroke subtypes such as large artery atherosclerotic stroke or small vessel stroke. Nevertheless, for individual loci substantial progress has been made in determining the specific mechanisms mediating stroke risk. In this review, we present a roadmap for functional follow-up of common risk variants associated with stroke. First, we discuss in silico strategies for characterizing signals in non-coding regions and highlight databases providing information on quantitative trait loci for mRNA and protein expression, as well as methylation, focussing on those with presumed relevance for stroke. Next, we discuss experimental strategies for following up on non-coding risk variants and regions such as massively parallel reporter assays, proteome-wide association studies, and chromatin conformation capture (3C) assays. These and other approaches are relevant for gaining insight into the specific variants and mechanisms mediating genetic stroke risk. Finally, we discuss how genetic findings could influence clinical practice by adding to diagnostic algorithms and eventually improve treatment options for stroke.

Common coding variant in SERPINA1 increases the risk for large artery stroke

Large artery atherosclerotic stroke (LAS) shows substantial heritability not explained by previous genome-wide association studies. Here, we explore the role of coding variation in LAS by analyzing variants on the HumanExome BeadChip in a total of 3,127 cases and 9,778 controls from Europe, Australia, and South Asia. We report on a nonsynonymous single-nucleotide variant in serpin family A member 1 (SERPINA1) encoding alpha-1 antitrypsin [AAT; p.V213A; P = 5.99E-9, odds ratio (OR) = 1.22] and confirm histone deacetylase 9 (HDAC9) as a major risk gene for LAS with an association in the 3'-UTR (rs2023938; P = 7.76E-7, OR = 1.28). Using quantitative microscale thermophoresis, we show that M1 (A213) exhibits an almost twofold lower dissociation constant with its primary target human neutrophil elastase (NE) in lipoprotein-containing plasma, but not in lipid-free plasma. Hydrogen/deuterium exchange combined with mass spectrometry further revealed a significant difference in the global flexibility of the two variants. The observed stronger interaction with lipoproteins in plasma and reduced global flexibility of the Val-213 variant most likely improve its local availability and reduce the extent of proteolytic inactivation by other proteases in atherosclerotic plaques. Our results indicate that the interplay between AAT, NE, and lipoprotein particles is modulated by the gate region around position 213 in AAT, far away from the unaltered reactive center loop (357-360). Collectively, our findings point to a functionally relevant balance between lipoproteins, proteases, and AAT in atherosclerosis.

Human cells involved in atherosclerosis have a sex

The influence of sex has been largely described in cardiovascular diseases. Atherosclerosis is a complex process that involves many cell types such as vessel cells, immune cells and endothelial progenitor cells; however, many, if not all, studies do not report the sex of the cells. This review focuses on sex differences in human cells involved in the atherosclerotic process, emphasizing the role of sex hormones. Furthermore, we report sex differences and issues related to the processes that determine the fate of the cells such as apoptotic and autophagic mechanisms. The analysis of the data reveals that there are still many gaps in our knowledge regarding sex influences in atherosclerosis, largely for the cell types that have not been well studied, stressing the urgent need for a clear definition of experimental conditions and the inclusion of both sexes in preclinical studies.

Association of Neutrophil/Lymphocyte Ratio with Plaque Morphology in Patients with Asymptomatic Intermediate Carotid Artery Stenosis

Background and Objectives

Non-calcified carotid plaques are more unstable than calcified plaques, and they are associated with a higher risk of rupture, thromboembolism, and consequently, stroke. The purpose of the present study is to compare calcified and non-calcified plaques that cause intermediate carotid artery stenosis with respect to neutrophil/lymphocyte ratio (NLR).

Subjects and Methods

A total number of 139 asymptomatic patients with 50-70% stenosis of the carotid artery were included in this study. Carotid Doppler ultrasound imaging and computed tomography angiography were performed to divide the carotid artery plaques into two groups as calcified and non-calcified. Patients included in the calcified (n=73) and non-calcified (n=66) plaque groups were compared with respect to total neutrophil count, lymphocyte count and NLR.

Results

Total lymphocyte count was statistically significantly lower in the non-calcified plaque group compared to the calcified plaque group (total lymphocyte count in non-calcified/calcified plaque groups [10³/mm³]: 2.1/2.3, respectively) (p=0.002). NLR was statistically significantly higher in the non-calcified plaque group compared to the calcified plaque group (NLR in non-calcified/calcified plaque groups: 2.6/2.1, respectively) (p<0.001). The cut-off value for NLR was found to be >2.54. Multivariate regression analysis showed that NLR was independently associated with non-calcified carotid artery plaques (odds ratio 5.686, 95% CI 2.498-12.944, p<0.001).

Conclusions

NLR is increased in the presence of non-calcified carotid artery plaques that cause asymptomatic intermediate stenosis. Increased NLR can be used as a marker to assess the risk of rupture of non-calcified carotid artery plaques.

A randomized phase II study of Xilonix, a targeted therapy against interleukin 1α, for the prevention of superficial femoral artery restenosis after percutaneous revascularization

OBJECTIVE

The purpose of this study was to evaluate an anti-interleukin 1α antibody for its ability to reduce acute postprocedural inflammation, thereby reducing neointimal hyperplasia and restenosis after superficial femoral artery (SFA) angioplasty. Restenosis of the SFA after endovascular intervention is a common problem leading to 1-year primary patency as low as 40%. These failures are primarily due to the development of neointimal hyperplasia, resulting from arterial wall inflammation.

METHODS

This was a randomized, phase II trial examining SFA restenosis in patients after percutaneous revascularization. Randomization occurred after successful revascularization, and patients were assigned to either the standard of care arm or the Xilonix (XBiotech USA, Inc, Austin, Tex) plus standard of care arm (N = 43). Xilonix was administered immediately after revascularization, every 2 weeks intravenously for four doses, and monthly subcutaneously until month 12. The major efficacy end points were target vessel event-free survival and incidence of major adverse cardiovascular events (MACEs).

RESULTS

At 12 months of follow-up, MACE (43% vs 36%; P = .76) and target vessel restenosis (24% vs 27%; log-rank, P = .79) rates were not significantly different between the groups. At 3-month follow-up, which covers the intravenous dosing period, a trend toward lower incidence of restenosis (0 of 22 [0%] vs 2 of 21 [10%]; P = .14) and MACE (2 of 22 [9%] vs 5 of 21 [24%]; P = .22) was observed in the Xilonix cohort. Adverse events were equally distributed in both arms.

CONCLUSIONS

Xilonix was well tolerated. Observed tendency to improved vessel patency with intravenous dosing suggests Xilonix could potentially represent a safe and effective therapeutic approach to preserving vessel patency.

Association between risk factors for vascular dementia and adiponectin

Vascular dementia is caused by various factors, including increased age, diabetes, hypertension, atherosclerosis, and stroke. Adiponectin is an adipokine secreted by adipose tissue. Adiponectin is widely known as a regulating factor related to cardiovascular disease and diabetes. Adiponectin plasma levels decrease with age. Decreased adiponectin increases the risk of cardiovascular disease and diabetes. Adiponectin improves hypertension and atherosclerosis by acting as a vasodilator and antiatherogenic factor. Moreover, adiponectin is involved in cognitive dysfunction via modulation of insulin signal transduction in the brain. Case-control studies demonstrate the association between low adiponectin and increased risk of stroke, hypertension, and diabetes. This review summarizes the recent findings on the association between risk factors for vascular dementia and adiponectin. To emphasize this relationship, we will discuss the importance of research regarding the role of adiponectin in vascular dementia.

Vascular dementia: different forms of vessel disorders contribute to the development of dementia in the elderly brain

The diagnosis of vascular dementia (VaD) describes a group of various vessel disorders with different types of vascular lesions that finally contribute to the development of dementia. Most common forms of VaD in the elderly brain are subcortical vascular encephalopathy, strategic infarct dementia, and the multi infarct encephalopathy. Hereditary forms of VaD are rare. Most common is the cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Sporadic forms of VaD are caused by degenerative vessel disorders such as atherosclerosis, small vessel disease (SVD) including small vessel arteriosclerosis, arteriolosclerosis, and lipohyalinosis, and cerebral amyloid angiopathy (CAA). Less frequently inflammatory vessel disorders and tumor-associated vessel lesions (e.g. angiocentric T-cell or angiotropic large cell lymphoma) can cause symptoms of dementia. Here, we review and discuss the impact of vessel disorders to distinct vascular brain tissue lesions and to the development of dementia in elderly individuals. The impact of coexisting neurodegenerative pathology in the elderly brain to VaD as well as the correlation between SVD and CAA expansion in the brain parenchyma with that of Alzheimer's disease (AD)-related pathology is highlighted. We conclude that "pure" VaD is rare and most frequently caused by infarctions. However, there is a significant contribution of vascular lesions and vessel pathology to the development of dementia that may go beyond tissue damage due to vascular lesions. Insufficient blood blow and alterations of the perivascular drainage mechanisms of the brain may also lead to a reduced protein clearance from extracellular space and subsequent increase of proteins in the brain parenchyma, such as the amyloid β-protein, and foster, thereby, the development of AD-related neurodegeneration. As such, it seems to be important for clinical practice to consider treatment of potentially coexisting AD pathology in cognitively impaired patients with vascular lesions.

Vascular dementia: Current concepts and nomenclature harmonization

Several types of cerebrovascular lesions are associated with cognitive decline, but the role of each type in dementia manifestation has yet to be determined. One of the greatest barriers of conducting clinicopathological studies in vascular dementia concerns the overlapping of nomenclature for these lesions. The aim of the present review was to discuss current nomenclature for cerebrovascular lesions and suggest modifications to allow better diagnostic reproducibility in this field.

Vascular pathology in the aged human brain

Cerebral atherosclerosis (AS), small vessel disease (SVD), and cerebral amyloid angiopathy (CAA) are the most prevalent arterial disorders in the aged brain. Pathogenetically, AS and SVD share similar mechanisms: plasma protein leakage into the vessel wall, accumulation of lipid-containing macrophages, and fibrosis of the vessel wall. CAA, on the other hand, is characterized by the deposition of the amyloid β-protein in the vessel wall. Despite these differences between CAA, AS and SVD, apolipoprotein E (apoE) is involved in all three disorders. Such a pathogenetic link may explain the correlations between AS, SVD, CAA, and Alzheimer’s disease in the brains of elderly individuals reported in the literature. In addition, AS, SVD, and CAA can lead to tissue lesions such as hemorrhage and infarction. Moreover, intracerebral SVD leads to plasma protein leakage into the damaged vessel wall and into the perivascular space resulting in a blood–brain barrier (BBB) dysfunction. This SVD-related BBB dysfunction is considered to cause white matter lesions (WMLs) and lacunar infarcts. In this review, we demonstrate the relationship between AS, SVD, and CAA as well as their contribution to the development of vascular tissue lesions and we emphasize an important role for apoE in the pathogenesis of vessel disorders and vascular tissue lesions as well as for BBB dysfunction on WML and lacunar infarct development.

The multifaceted contributions of leukocyte subsets to atherosclerosis: lessons from mouse models

Chronic inflammation drives the development of atherosclerosis, and details regarding the involvement of different leukocyte subpopulations in the pathology of this disease have recently emerged. This Review highlights the surprising contribution of granulocyte subsets and mast cells to early atherogenesis and subsequent plaque instability, and describes the complex, double-edged role of monocyte, macrophage and dendritic-cell subsets through crosstalk with T cells and vascular progenitor cells. Improved understanding of the selective contributions of specific cell types to atherogenesis will pave the way for new targeted approaches to therapy.

Management of atherosclerosis with antiallergic medicine: a lesson from the mouse model

Evaluation of: Sun J, Sukhova GK, Wolters PJ et al.: Mast cells promote atherosclerosis by releasing pro-inflammatory cytokines. Nat. Med. 13, 719-724 (2007). Mast cells are important components in human allergic response and innate immunity. These cells have been implicated in the pathogenesis of atherosclerosis since the 1950s, and a series of studies have proposed their roles in the pathologic events critical to atherogenesis. Despite these studies and hypotheses, there is no evidence to suggest a direct participation of these allergic cells in atherosclerosis. Using mast cell-deficient mice and intravenous mast cell reconstitution technology with a conventional mouse atherosclerosis model, Dr Sun et al. revealed that mast cells contribute to atherogenesis by releasing proinflammatory cytokines, which are utilized to stimulate vascular cell-protease expression and further tissue remodeling. Mice that lack these cells are resistant to diet-induced atherosclerosis. These data suggest that stabilization of mast cells with antiallergic medicine may be utilized in controlling or preventing the initiation and progression of atherosclerosis in humans.