Pathophysiological Mechanisms of Carotid Plaque Vulnerability: Impact on Ischemic Stroke

Relationship Between Subclavian Artery Stenosis Lesions and Posterior Circulation Infarction: A Preliminary Study

BACKGROUND

To investigate the correlation between subclavian steal syndrome and posterior circulation infarction using magnetic resonance imaging.

METHODS

A total of 294 patients diagnosed with subclavian steal syndrome using carotid Doppler ultrasonography were retrospectively included. According to the magnetic resonance imaging results, they were divided into posterior circulation infarction group and nonposterior circulation infarction group. Clinical indicators and carotid Doppler ultrasound parameters of patients were collected, and they were screened to establish a multiple logistic regression model. Receiver operating characteristic curve analysis of the established multiple logistic regression model was performed, and the area under the curve was calculated to evaluate the predictive efficiency of the model.

RESULTS

After statistical analysis of all parameters of the 2 groups of patients, a total of 10 parameters were included in multiple logistic regression to establish a model. The results showed a correlation between posterior circulation infarction and subclavian artery occlusion, grade III subclavian steal syndrome, gender, vulnerable plaques, National Institutes of Health Stroke Scale score, and age. After the receiver operating characteristic curve analysis of the model, the area under the curve for the multiple logistic regression model was 0.773.

CONCLUSIONS

The multiparameter composite model based on clinical baseline data and carotid Doppler ultrasonography parameters can effectively predict posterior circulation infarction and offer novel insight for clinical diagnosis.

Impact of carotid stenosis on the outcome of stroke patients submitted to reperfusion treatments: a narrative review

Intravenous thrombolysis (IT) and mechanical thrombectomy (MD) are the two interventional approaches that have changed the outcome of patients with acute ischemic stroke (AIS). Ipsilateral and contralateral carotid stenosis (ICS, CCS) play an important role in regulating cerebral hemodynamics, both in chronic and acute situations such as AIS. Several studies have explored their role in the incidence and severity of stroke, but very few have investigated the possible impact of ICS and CCS on the efficacy of interventional procedures. The purpose of this review was to I) highlight the incidence and prevalence of carotid stenosis (CS); II) assess the impact of ICS and CCS on cerebral hemodynamics; III) evaluate the effect of carotid stenosis on the efficacy of interventional therapies (IT and MT) for AIS; and IV) report therapeutic complications related to CS. We searched PubMed/Medline for case reports, reviews, and original research articles on English-language review topics during the period from January 1, 2000 to October 1, 2023. CS is associated with 15-20 % of the total number of AIS. ICS and CCS had a negative influence on both cerebral hemodynamics before AIS and outcome after interventional procedures (IT, MT alone or in bridging). Available data on cerebral hemodynamics and efficacy of interventional therapies for AIS suggest a negative role of CS. Therefore, early diagnosis of CS may be considered relevant to preventive and post-stroke treatment strategies.

B-mode ultrasound characteristics of carotid plaques in symptomatic and asymptomatic patients with low-grade stenosis

Carotid plaque features assessed using B-mode ultrasound can be useful for the prediction of cerebrovascular symptoms. Therefore, the aim of this retrospective study was to determine the ability of ultrasound B-mode imaging to differentiate between carotid plaques causing less than 50% stenosis in symptomatic and asymptomatic patients. A dataset of 1,593 patients with carotid disease who underwent carotid ultrasound between 2016 and 2021 was evaluated retrospectively between January and April of 2022. A total of 107 carotid plaques from 35 symptomatic and 52 asymptomatic patients causing low-grade stenosis on B-mode images were included in the analysis. Chi-square, independent t-test and Mann-Whitney U test were used to compare the variables. There was a significant association between hypertension and the presence of cerebrovascular symptoms (p = 0.01). Predominantly hypoechoic and hyperechoic carotid plaque were significantly associated with the presence and absence of cerebrovascular symptoms, respectively (predominantly hypoechoic: p = 0.01; predominantly hyperechoic: p = 0.02). Surface irregularity was significantly associated with the presence of cerebrovascular symptoms (p = 0.02). There is was a significant difference in the carotid plaque length and area between the symptomatic and asymptomatic patients (plaque length: symptomatic median 9 mm, interquartile range [IQR] 6 mm; asymptomatic median 6 mm, IQR 4.5 mm, p = 0.01; plaque area: symptomatic median 24 mm, IQR 30 mm; asymptomatic median 14 mm, IQR 17 mm, p = 0.01); however, this difference was not significant for plaque thickness (p = 0.55), or common carotid artery intima-media thickness (p = 0.7). Our findings indicate that hypertension patients with predominantly hypoechoic carotid plaques and plaques with an irregular surface are associated with the presence of cerebrovascular symptoms. In addition, the carotid plaques in symptomatic patients were longer and larger compared to asymptomatic patients.

Association among VKORC1 rs9923231, CYP4F2 rs2108622, GGCX rs11676382 polymorphisms and acute ischemic stroke

Acute ischemic stroke is a major cause of morbidity and mortality worldwide, and genetic factors play a role in the risk of stroke. Single nucleotide polymorphisms (SNPs) in the VKORC1, CYP4F2, and GGCX genes have been linked to clinical outcomes, such as bleeding and cardiovascular diseases. This study aimed to investigate the association between specific polymorphisms in these genes and the risk of developing the first episode of acute ischemic stroke in patients without a known embolic source. This retrospective, cross-sectional, observational, analytical, case-control study included adult patients diagnosed with acute ischemic stroke. The SNPs in VKORC1 rs9923231, CYP4F2 rs2108622, GGCX rs11676382 genes were genotyped and analyzed together with the demographic and clinical factors of the 2 groups of patients. The presence of SNPs in VKORC1 or CYP4F2 genes significantly increased the risk of ischemic stroke in the context of smoking, arterial hypertension, and carotid plaque burden. The multivariate logistic model revealed that smoking (odds ratio [OR] = 3.920; P < .001), the presence of carotid plaques (OR = 2.661; P < .001) and low-density lipoprotein cholesterol values >77 mg/dL (OR = 2.574; P < .001) were independently associated with stroke. Polymorphisms in the VKORC1 and CYP4F2 genes may increase the risk of ischemic stroke in patients without a determined embolic source. Smoking, the presence of carotid plaques, and high low-density lipoprotein cholesterol levels were reconfirmed as important factors associated with ischemic stroke.

Swiss Vascular Biobank: Evaluation of Optimal Extraction Method and Admission Solution for Preserving RNA from Human Vascular Tissue

Proper biobanking is essential for obtaining reliable data, particularly for next-generation sequencing approaches. Diseased vascular tissues, having extended atherosclerotic pathologies, represent a particular challenge due to low RNA quality. In order to address this issue, we isolated RNA from vascular samples collected in our Swiss Vascular Biobank (SVB); these included abdominal aortic aneurysm (AAA), peripheral arterial disease (PAD), healthy aorta (HA), and muscle samples. We used different methods, investigated various admission solutions, determined RNA integrity numbers (RINs), and performed expression analyses of housekeeping genes (ACTB, GAPDH), ribosomal genes (18S, 28S), and long non-coding RNAs (MALAT1, H19). Our results show that RINs from diseased vascular tissue are low (2-4). If the isolation of primary cells is intended, as in our SVB, a cryoprotective solution is a better option for tissue preservation than RNAlater. Because RNA degradation proceeds randomly, controls with similar RINs are recommended. Otherwise, the data might convey differences in RNA degradation rather than the expressions of the corresponding genes. Moreover, since the 18S and 28S genes in the diseased vascular samples were degraded and corresponded with the low RINs, we believe that DV200, which represents the total RNA's disintegration state, is a better decision-making aid in choosing samples for omics analyses.

Diagnostic Performance of Contrast-Enhanced Ultrasound and High-Resolution Magnetic Resonance Imaging for Carotid Atherosclerotic Plaques: A Systematic Review and Meta-Analysis

OBJECTIVES

The aim of this meta-analysis was to evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) and high-resolution magnetic resonance imaging (HR-MRI) in patients with carotid vulnerable plaques.

METHODS

A systematic review was conducted in PubMed, Embase, Cochrane Library, and Web of Science using the search terms carotid artery, atherosclerotic plaque, CEUS, contrast-enhanced ultrasound, HR-MRI, and high-resolution magnetic resonance. Studies published since the establishment of the library until December 2021 were retrieved. The statistical analyses were performed with Meta-DiSc version 1.4. Beyond that, the potential sources of heterogeneity for CEUS and HR-MRI were explored.

RESULTS

Nine articles were included in this study. For CEUS, the pooled sensitivity and specificity for detecting carotid vulnerable plaques 91% (95% confidence interval [CI]: 84%, 95%) and 67% (95% CI: 54%, 79%), respectively. For HR-MRI, the pooled sensitivity and specificity were 78% (95% CI: 72%, 83%) and 65% (95% CI, 56%, 73%), respectively. The area under the summary receiver operating characteristic curve for CEUS and HR-MRI were 0.9218 and 0.8129, respectively. However, the difference in diagnostic accuracy between CEUS and HR-MRI diagnostic accuracy was not statistically significant.

CONCLUSIONS

The study shows that the sensitivity of CEUS was higher than that of HR-MRI, and the specificity was similar to HR-MRI. CEUS and HR-MRI provide a similar diagnostic yield in detecting a vulnerable plaque. Thus, CEUS may be a useful tool for the diagnosis of carotid vulnerable plaques.

The Probable Role of Chlamydia pneumoniae Infection in Acute Stroke

Cardiovascular diseases are the most leading cause of worldwide mortality. According to USA statistics, about 1 of 6 cardiovascular deaths is due to stroke. Stroke is the second most common cause of death and a chief cause of disability due to EU data. Treatment, care providing, rehabilitation costs and with the labor loss, the overall cost in EU due to stroke was estimated about €45 billion in year 2017. Acute stroke due to infectious diseases via several possible mechanisms with various clinical presentations were previously reported in the literature. Chlamydia pneumoniae is an obligate intracellular bacteria and extremely common in adult individuals. Besides it being a major cause of pneumonia in adults, association between atherosclerosis and vascular diseases was demonstrated by several sero-epidemiological studies and by direct detection of organism in atherosclerotic lesions by electron microscopy, immunohistochemistry, polymerase chain reaction. Also, several sero-epidemiological studies have demonstrated a link between Chlamydia pneumoniae infection and acute stroke. In this chapter, we will summarize the data in literature regarding the association between Chlamydia pneumoniae infection and acute stroke and we will try to explain the possible mechanisms that could be responsible in pathophysiology of stroke in these patients.

Vascular dysfunction in COVID-19 patients: update on SARS-CoV-2 infection of endothelial cells and the role of long non-coding RNAs

Although COVID-19 is primarily a respiratory disease, it may affect also the cardiovascular system. COVID-19 patients with cardiovascular disorder (CVD) develop a more severe disease course with a significantly higher mortality rate than non-CVD patients. A common denominator of CVD is the dysfunction of endothelial cells (ECs), increased vascular permeability, endothelial-to-mesenchymal transition, coagulation, and inflammation. It has been assumed that clinical complications in COVID-19 patients suffering from CVD are caused by SARS-CoV-2 infection of ECs through the angiotensin-converting enzyme 2 (ACE2) receptor and the cellular transmembrane protease serine 2 (TMPRSS2) and the consequent dysfunction of the infected vascular cells. Meanwhile, other factors associated with SARS-CoV-2 entry into the host cells have been described, including disintegrin and metalloproteinase domain-containing protein 17 (ADAM17), the C-type lectin CD209L or heparan sulfate proteoglycans (HSPG). Here, we discuss the current data about the putative entry of SARS-CoV-2 into endothelial and smooth muscle cells. Furthermore, we highlight the potential role of long non-coding RNAs (lncRNAs) affecting vascular permeability in CVD, a process that might exacerbate disease in COVID-19 patients.

Risks of Carotid Artery Stenosis and Atherosclerotic Cardiovascular Disease in Patients with Calcium Kidney Stone: Assessment of Systemic Inflammatory Biomarkers

(1) Background: To assess the clinical significance of preoperative inflammatory biomarkers combined with atherosclerotic cardiovascular disease (ASCVD) risk score to evaluate carotid artery stenosis in patients with calcium kidney stones; (2) Methods: We conducted a prospective observational case-control study, enrolling 74 patients with calcium kidney stones and 66 age- and sex-matched healthy controls. We calculated the inflammatory biomarkers including the neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), and systemic inflammation response index (SIRI). An ultrasound of the carotid arteries was performed on all participants to identify the severity of the stenosis; (3) Results: All inflammatory biomarkers and the severity of carotid artery stenosis were higher in the calcium kidney stone group than in controls. After stratification of ASCVD, inflammatory biomarkers and carotid artery stenosis severity were still significantly higher in the calcium kidney stone group. Multivariate analyses showed that calcium kidney stones significantly increased the risk of ASCVD and carotid artery stenosis. In multivariate linear logistic regression analyses, calcium kidney stone and ASCVD score had a significant association with carotid artery occlusion, but SIRI did not; (4) Conclusions: Calcium kidney stone is associated with higher levels of inflammatory biomarkers and carotid artery stenosis. Calcium kidney stone is associated with higher levels of inflammatory biomarkers and carotid artery stenosis.

Alterungsbedingte Gefäßveränderungen am Beispiel der Arteria carotis

Einer der Hauptrisikofaktoren für das Vorliegen einer Karotisstenose und des karotisbedingten Schlaganfalls ist das Lebensalter. Ziel dieses Übersichtsartikels ist die Darstellung des aktuellen Wissensstands über altersbedingte Veränderungen der Gefäße am Beispiel der Karotisstenose.

Die Gefäßalterung (vaskuläre Seneszenz) als Abnahme struktureller und funktioneller Eigenschaften der Gefäßwand spielt sich auf verschiedenen Ebenen ab. Auf multizellulärer Ebene kommt es mit zunehmendem Alter hauptsächlich aufgrund von atherosklerotischen Veränderungen der Gefäßwand zu einer Zunahme von Gefäßvolumen und -durchmesser sowie der Intima-Media-Dicke. Auf zellulärer und extrazellulärer Ebene kommt es zur Abnahme von Elastinfasern, glatten Muskelzellen und der Gesamtzellularität sowie zur Zunahme der Lipid‑, Cholesterin- und Kalziumphosphatablagerungen und der Neovaskularisierung. Ursachen der Gefäßalterung auf molekularer Ebene sind insbesondere oxidativer Stress, chronische Entzündungsreaktion, mitochondriale Dysfunktion, epigenetische Veränderungen, Dysregulation der Expression nicht kodierender RNAs (ncRNAs) und die Zunahme der Seneszenz. Der altersbedingte Verlust der Heilungs- und Reparaturfähigkeit des Gewebes macht die Plaques vulnerabler und im Falle der A. carotis anfälliger für ischämische Schlaganfälle.

Zunehmende Erkenntnisse über den Einfluss des Alterns auf die Epigenetik und der ncRNAs in atherosklerotischen Plaques kann zukünftig das individuelle Risiko von Patienten genauer quantifizieren und zur Entwicklung zielgerichteter Therapiestrategien beitragen. Weitere Studien sind auf diesem Gebiet jedoch notwendig, um das gesamte Ausmaß der Gefäßalterung und den damit einhergehenden Erkrankungen zu verstehen, damit diesen dann gezielt entgegenwirkt werden kann.

Detecting the vulnerable carotid plaque: the Carotid Artery Multimodality imaging Prognostic study design

BACKGROUND

Carotid artery disease is highly prevalent and a main cause of ischemic stroke and vascular dementia. There is a paucity of information on predictors of serious vascular events. Besides percentage diameter stenosis, international guidelines also recommend the evaluation of qualitative characteristics of carotid artery disease as a guide to treatment, but with no agreement on which qualitative features to assess. This inadequate knowledge leads to a poor ability to identify patients at risk, dispersion of medical resources, and unproven use of expensive and resource-consuming techniques, such as magnetic resonance imaging, positron emission tomography, and computed tomography.

OBJECTIVES

The Carotid Artery Multimodality imaging Prognostic (CAMP) study will: prospectively determine the best predictors of silent and overt ischemic stroke and vascular dementia in patients with asymptomatic subcritical carotid artery disease by identifying the noninvasive diagnostic features of the 'vulnerable carotid plaque'; assess whether 'smart' use of low-cost diagnostic methods such as ultrasound-based evaluations may yield at least the same level of prospective information as more expensive techniques.

STUDY DESIGN

We will compare the prognostic/predictive value of all proposed techniques with regard to silent or clinically manifest ischemic stroke and vascular dementia. The study will include ≥300 patients with asymptomatic, unilateral, intermediate degree (40-60% diameter) common or internal carotid artery stenosis detected at carotid ultrasound, with a 2-year follow-up. The study design has been registered on Clinicaltrial.gov on December 17, 2020 (ID number NCT04679727).

Agonist-induced Piezo1 activation promote mitochondrial-dependent apoptosis in vascular smooth muscle cells

OBJECTIVE

Mechanical damage plays an essential role in the progression of atherosclerosis. Piezo1 is a new mechanically sensitive ion channel. The present study investigated the vascular smooth muscle cells (VSMCs) apoptosis induced by Piezo1 activation and explored its underlying mechanism.

METHODS

We evaluated cell viability and apoptosis rate with cell counting kit-8 (CCK-8) and Annexin V-FITC/PI flow cytometry assay, respectively. And then Western blot was performed to measure the relative protein. Reactive oxygen species (ROS) and intracellular Ca²⁺ were assessed via fluorescence microscope, and the mitochondrial transmembrane potential was monitored by JC-10 staining.

RESULTS

Our in vitro study revealed that mice in the ApoE-/- group compared with control mice showed higher Piezo1 expression(P < 0.05). Besides, Yoda1, a Piezo1 agonist, triggered Ca²⁺ overload, mitochondrial damage, accumulation of ROS, and VSMCs apoptosis in a dose-depend manner. Furthermore, BAPT-AM (an intracellular Ca²⁺ chelator) and NAC (an antioxidant) suppressed the mitochondrial damage and attenuated the VSMCs apoptosis.

CONCLUSION

Our study suggested that Piezo1 induced VSMCs apoptosis because of Ca²⁺ overload, excessive ROS generation, and mitochondrial dysfunction, which indicated that Piezo1 has potential value in treating vascular diseases.

Admission Serum Calcium Level and Short-Term Mortality After Acute Ischemic Stroke: A Secondary Analysis Based on a Norwegian Retrospective Cohort

Background

Disturbed serum calcium levels are related to the risk of stroke. However, previous studies exploring the correlation between serum calcium and the clinical outcome of ischemic stroke (IS) have shown inconsistent results.

Object

The study aimed to investigate the relationship between admission serum calcium and 30-day mortality in patients with IS.

Methods

A total of 876 IS patients from a Norwegian retrospective cohort were included for secondary analysis. The exposure variable and the primary outcome were albumin-corrected serum calcium (ACSC) at baseline and all-cause mortality within 30 days after the first admission, respectively. Multivariable logistic regression analysis was used to estimate the risk of 30-day mortality according to ACSC levels. Moreover, the potential presence of a non-linear relationship was evaluated using two-piecewise linear regression with a smoothing function and threshold level analysis. The stability of the results was evaluated by unadjusted and adjusted models.

Results

The result of multiple regression analysis showed that ACSC at baseline was positively associated with the incidence of 30-day mortality after adjusting for the potential confounders (age, gender, serum glucose, hypertension, atrial fibrillation/atrial flutter, renal insufficiency, heart failure, chronic obstructive pulmonary disease, pneumonia, paralysis, and aphasia) (OR = 2.43, 95% CI 1.43–4.12). When ACSC was translated into a categorical variable, the ORs and 95% CIs in the second to the fourth quartile vs. the first quartile were 1.23 (0.56, 2.69), 1.16 (0.51, 2.65), and 2.13 (1.04, 4.38), respectively (P for trend = 0.03). Moreover, the results of two-piecewise linear regression and curve-fitting revealed a linear relationship between ACSC and 30-day mortality.

Conclusion

ACSC is positively associated with 30-day mortality in IS patients, and the relationship between them is linear.

The Predictive Value of Contrast-Enhanced Ultrasound Combined with Serum miR-124 Level in Acute Cerebral Infarction and Their Correlation with the Contrast Enhancement of Carotid Atherosclerotic Plaque

OBJECTIVE

To investigate the predictive value of contrast-enhanced ultrasound (CEUS) combined with serum miR-124 level in acute cerebral infarction (ACI) and their association with the contrast enhancement of carotid atherosclerotic plaque.

METHODS

Totally 60 patients diagnosed with ACI and 60 controls were included in the study. All the subjects had carotid atherosclerotic plaques, and all of them were examined by CEUS and were tested for serum miR-124 levels.

RESULTS

Time to peak (TTP) and mean transit time (MTT) in the ACI group were significantly shorter than those in the control group (P < 0.05), but the peak intensity ratio (PIR), the area under the curve (AUC), and relative expression levels of serum miR-124 were notably greater in the ACI group (P < 0.05). There were statistically significant differences in TTP, MTT, PIR, AUC, and serum miR-124 expression in patients with different cerebral infarct areas in the ACI group (P < 0.05). Besides, the sensitivity and specificity of serum miR-124 levels for the prediction of ACI were 71.67% and 90.00%, respectively, with a cut-off value of 1.52, and the sensitivity was 86.67% and specificity was 93.33% of CEUS combined with serum miR-124 in the prediction of ACI. The ACI group showed a higher proportion of grades 2 and 3 (P < 0.001). Pearson correlation analysis showed that the intraplaque contrast enhancement was negatively related to TTP and MTT but had a positive correlation with PIR, AUC, and serum miR-124 levels.

CONCLUSION

Grades 2 and 3 intraplaque contrast enhancement and serum miR-124 level of 1.52 had high sensitivity and specificity to predict ACI. Moreover, the CEUS parameters combined with serum miR-124 level could improve the performance in predicting ACI and had auxiliary value in evaluating the stability of carotid atherosclerotic plaques.

Correlation between neutrophil-to-lymphocyte ratio and stability of carotid plaques

OBJECTIVE

The neutrophil-to-lymphocyte ratio (NLR) has been proved to be a strong predictor of carotid atherosclerotic plaque, but the correlation between NLR and the stability of carotid plaque is not clear. Thus we conducted a study to evaluate the correlation between NLR and the stability of carotid atherosclerotic plaque, and to develop a new evaluation scale for rapid clinical evaluation of carotid plaque stability.

METHODS

We recruited 528 patients with acute anterior circulation ischemic stroke who were in accordance with extracranial and intracranial large artery atherosclerosis of Chinese ischemic stroke subtype. Blood routine examination and carotid ultrasound examination were performed on admission. According to the ultrasonic characteristics, the patients were divided into plaque stabilization group and plaque instability group.

RESULTS

There was significant difference in NLR between plaque stability and instability groups (P < 0.001). The risk of plaque instability increased with the increase of NLR (odds ratio (OR), 4.737; 95% confidence interval (CI), 3.404-6.592; P < 0.001). Receiver operating characteristic (ROC) curve showed that the critical point of NLR is 2.55 and the area under the curve (AUC) was 0.782 (95%CI, 0.740-0.823; P < 0.001). The best cut-off value of the evaluation scale was ≥ 4 points (sensitivity, 0.77; specificity, 0.75; accuracy, 0.76).

CONCLUSION

There is a correlation between NLR and carotid plaque instability. NLR may be useful as a potential inflammation biomarker indicating the risk of unstable carotid plaques. The new scoring scale is a reliable index to predict the stability of carotid plaque.

Circadian misalignment promotes vascular smooth muscle cell apoptosis via defective autophagy

Defective autophagy in vascular smooth muscle cells (VSMCs) in response to oxidative stress can lead to cellular apoptosis and plaque instability. Previous studies have revealed that the circadian clock system is involved in autophagic regulation and plaque progression. However, the mechanism by which circadian rhythmicity influences VSMC autophagy and plaque stability remains unclear. Our study described the circadian profiles in atheromatous plaques and verified the role of circadian misalignment in VSMC autophagy and apoptosis. We found that the mRNA expression levels of circadian locomotor output cycles protein kaput (CLOCK) and Beclin 1 were significantly decreased in unstable plaques compared with stable plaques. No significant differences were observed in other circadian rhythm genes. VSMCs treated with oxidized low-density lipoprotein (ox-LDL, 80 μg/ml) exhibited abnormal circadian rhythmicity and impaired autophagy, as evidenced by consistent decreases in CLOCK and Beclin 1 expression, suggesting a correlation between CLOCK and autophagy. CLOCK protein expression was inhibited by ox-LDL, accompanied by defective autophagy and an increased apoptosis rates (P < 0.05). Administration of rapamycin (10 nM) reversed the effect of ox-LDL on VSMC autophagy and apoptosis. Finally, CLOCK silencing led to a considerable decrease in autophagy. VSMCs with stable CLOCK silencing also showed an increased apoptosis rate. In addition, gene silencing of CLOCK in VSMCs counteracted the effects of moderate rapamycin concentrations on autophagy and apoptosis. In conclusion, these findings suggested that the CLOCK-dependent rapamycin signaling pathway is a critical mediator in ox-LDL-induced VSMCs with defective autophagy that exacerbates plaque destabilization.

Vulnerable Plaque Is More Prevalent in Male Individuals at High Risk of Stroke: A Propensity Score-Matched Study

OBJECTIVES

To assess the gender differences in the prevalence of carotid vulnerable plaques in high-risk individuals for stroke in a multicenter, cross-sectional study.

METHODS

In the year 2015, 18595 residents who were at the age of 40 or older participated in a face-to-face study in eight communities in southwestern China. Totally 2,644 participants at high risk of stroke were enrolled. Before and after propensity score matching (PSM), the prevalence of carotid plaques and vulnerable plaques were compared between men and women. Multivariate analyses were applied to explore the association between the gender and carotid plaques. Stratified analyses and interaction tests were performed to identify factors that might modify the association between the gender and carotid plaques.

RESULTS

Among 2644 high-risk individuals enrolled, there were 1,202 (45.5%) men and 1442 (54.5%) women. Carotid plaques were detected in 904 (34.2%) participants, while vulnerable plaques were found in 425 (16.1%) participants. Before PSM, carotid plaques were more prevalent in male individuals than the female (36.7% vs. 32.1%, p = 0.01), as well as vulnerable plaque (20.0% vs. 12.8%, p < 0.01). Men tend to have a higher prevalence of vulnerable plaques in multivariate analyses (adjusted OR 1.70, 95% CI 1.10-2.62, p = 0.02). Stratified analyses and interaction tests demonstrated that the association between male sex and vulnerable carotid plaque did not change by age, family history of stroke, histories of chronic disease, smoking status, drinking status, physical activity, and BMI (all p for interaction > 0.05). After PSM, vulnerable plaques were still more prevalent in male individuals than the female (17.03% vs. 12.07%, p = 0.032).

CONCLUSION

Male individuals had a higher risk of vulnerable carotid plaque independent of classical vascular risk factors. Whether there is a gender-specific association between variations in genes related to inflammation, lipid metabolis, and endothelial function and plaque vulnerability needs to be further studied.

Omentin-1: Protective impact on ischemic stroke via ameliorating atherosclerosis

Omentin-1, a newly identified adipokine, has recently been revealed as a novel biomarker for ischemic stroke (IS). Low circulating omentin-1 levels could indicate a high risk of IS, and elevated omentin-1 levels exert a favorable impact on cerebral ischemia. Furthermore, omentin-1 has anti-atherosclerotic, anti-inflammatory, and cardiovascular protective capabilities through the intracellular Akt/AMP-activated protein kinase (AMPK)/ nuclear factor-κB (NF-κB) and certain protein kinase (ERK, JNK, and p38) signaling pathways. Omentin-1 also alleviates endothelial cell dysfunction, improves revascularization via the Akt-endothelial nitric-oxide synthase (eNOS) regulatory axis, promotes endothelium-dependent vasodilation through endothelium-derived NO in an eNOS fashion, and inhibits VSMC proliferation by means of AMPK/ERK signaling pathways, VSMC migration via inactivation of the NADPH oxidase (NOX)/ROS/p38/HSP27 pathways and artery calcification via the PI3K-Akt pathway. These findings indicate that omentin-1 may be a negative mediator of IS. Pharmacologically, several lines of clinical evidence indicate that metformin and statins could elevate omentin-1 levels, although the specific mechanism has not been precisely delineated until now. This study is the first to summarize the comprehensive mechanisms between omentin-1 and atherosclerosis and to review the shielding effect of omentin-1 on IS. We shed light on omentin-1 as a novel therapeutic target for combating IS.

Similarities and differences in ultrasound of extracranial brachiocephalic atherosclerotic lesions in patients with ischemic anterior and posterior circulation stroke

Aim. To establish similarities and differences in ultrasound of extracranial brachiocephalic atherosclerotic lesions in patients with ischemic anterior and posterior circulation stroke.

Material and methods. The study involved 668 patients (men, 370; women, 298) with carotid territory IS aged 63±11 and 69±9 years, respectively, and 235 patients (men, 129; women, 106) with vertebrobasilar (VB) territory IS aged 59±12 and 63±10 years, respectively, who underwent duplex ultrasound.

Results. Atherosclerotic plaques (ASP) in the internal carotid arteries (ICA) were diagnosed significantly more often (p<0,05) (right ICA (ICAr) — 44,0% of cases; left ICA (ICAl) — 48,4%) and the degree of stenosis of ICA mouths was significantly higher (p<0,05) (ICAr —53±23%, ICAl — 54±24%) in carotid territory IS than in VB territory IS (ICAr — 34,0% of cases; average degree of stenosis — 47±18%; ICAl — 33,6%, average degree of stenosis — 46±18%. There were no significant differences in the prevalence of ASP in vertebral arteries and related stenosis in IS in both territories. Also, there were no significant intergroup differences in the prevalence of homogeneous anechoic or hypoechoic and heterogeneous with hypoechoic predominance ASPs in the ICA mouths: in carotid territory IS, such ASPs were detected in each ICA in 33,5% of cases; in VB territory IS, in 29,6% of cases.

Conclusion. In patients with carotid and VB territory IS, risky ASPs were recorded with the same frequency, while the overall prevalence of ASPs and the stenosis degree of ICA mouths was significantly higher in carotid IS.

 

Potential Role of Melatonin as an Adjuvant for Atherosclerotic Carotid Arterial Stenosis

Carotid artery stenosis (CAS) is an atherosclerotic disease characterized by a narrowing of the artery lumen and a high risk of ischemic stroke. Risk factors of atherosclerosis, including smoking, hypertension, hyperglycemia, hyperlipidemia, aging, and disrupted circadian rhythm, may potentiate atherosclerosis in the carotid artery and further reduce the arterial lumen. Ischemic stroke due to severe CAS and cerebral ischemic/reperfusion (I/R) injury after the revascularization of CAS also adversely affect clinical outcomes. Melatonin is a pluripotent agent with potent anti-inflammatory, anti-oxidative, and neuroprotective properties. Although there is a shortage of direct clinical evidence demonstrating the benefits of melatonin in CAS patients, previous studies have shown that melatonin may be beneficial for patients with CAS in terms of reducing endothelial damage, stabilizing arterial plaque, mitigating the harm from CAS-related ischemic stroke and cerebral I/R injury, and alleviating the adverse effects of the related risk factors. Additional pre-clinical and clinical are required to confirm this speculation.

Can carotid artery calcifications on dental radiographs predict adverse vascular events? A systematic review

OBJECTIVES

To investigate the predictive value of carotid artery calcifications (CACs) seen on dental imaging for future adverse events related to cerebrovascular and cardiovascular diseases.

METHODS

Electronic databases (PubMed, Embase, SCOPUS and Cochrane) and selected grey literature were searched. Outcomes included stroke, transient ischaemic attack (TIA), myocardial infarction (MI), angina, heart failure, future interventional revascularization procedures and death. Risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

5 studies were selected from 1011 records. All were of moderate to low risk of bias. Results were heterogeneous but showed that patients with CACs on panoramic radiographs (PANs) were more likely to experience strokes, TIA, MI and future revascularization procedures compared to control groups. The differences between groups were not all found to be statistically significant. Bilateral vessel-outlining CACs were an independent risk marker for future vascular events. Patients who are not currently being managed for cardiovascular risk factors should be referred for further evaluation. Those already being treated for atherosclerosis may not benefit from additional investigations.

CONCLUSION

The evidence for the predictive value of CACs on PANs for adverse future vascular events is equivocal but can help to identify at-risk patients who require further evaluation.

CLINICAL RELEVANCE

Dentists must be able to recognize CACs on PANs and make appropriate referrals for patients to be evaluated for cardiovascular risk factors, especially those who have not previously been assessed.

Brachiocephalic atherosclerosis in patients with posterior circulation ischemic stroke

Aim. To study echographic and acoustic characteristics of atherosclerotic plaques (ASP) in brachiocephalic arteries (BCA) in patients with acute posterior circulation ischemic stroke (PCIS).

Material and methods. In this study we included data of duplex ultrasound from 235 patients (men, 129; women, 106; age, 59±12 and 63±10 years, respectively) with PCIS. Pathogenesis of PCIS was established only in 23 cases: in 17 (74%) — atherothrombosis, in 3 (13%) — cardioembolism, in 3 (13%) — lacunar stroke. Atrial fibrillation was established in 18,5% of patients. A total of 903 asymptomatic individuals were included in the control group, comparable with studied patients by sex and age.

Results. The prevalence of ASP in vertebral arteries (VA) was equal in both groups. Also, no significant differences in the degree of VA stenosis were observed. Atherosclerotic lesions of common (CCA) and internal carotid arteries (ICA) on both sides were more often observed in control group, but the degree of their stenosis was higher in PSIS group (р<0,003). In ischemic stroke, stenosis of the right ICA was 47±17%, left ICA — 46±18%, while in asymptomatic individuals, right ICA stenosis was 40±14%, left ICA — 39±15%. In patients with PCIS, ASPs were significantly more often regarded as concentric (22,0% vs 10,4% in PCIS and asymptomatic individuals, respectively), prolonged (24,2% vs 7,5%), homogeneous (41,0% vs 21,1%), as well as were more likely to have an uneven contour (27,7% vs 2,8%).

Conclusion. In patients with acute PCIS, the peculiarities of BCA atherosclerosis were recorded, distinguishing it from that in the asymptomatic population.

The carotid plaque as paradigmatic case of site-specific acceleration of aging process: The microRNAs and the inflammaging contribution

Atherosclerosis is considered a chronic inflammatory disease of arteries associated with the aging process. Many risk factors have been identified and they are mainly related to life-styles, gene-environment interactions and socioeconomic status. Carotid and coronary artery diseases are the two major atherosclerotic conditions, being the primary cause of stroke and heart attack, respectively. Nevertheless, carotid plaque assumes particular aspects not only for the specific molecular mechanisms, but also for the types of atheroma which may be associated with a better or a worst prognosis. The identification of circulating blood biomarkers able to distinguish carotid plaque types (stable or vulnerable) is a crucial step for the improvement of adequate therapeutic approaches avoiding or delaying endarterectomy in the oldest old individuals (> 80 years), a population predicted to growth in the next years. The review highlights the most recent knowledge on carotid plaque molecular mechanisms, focusing on microRNAs (miRs), as a site-specific accelerated aging within the conceptual framework of Geroscience for new affordable therapies.

Oxidative Stress and Inflammation, Key Targets of Atherosclerotic Plaque Progression and Vulnerability: Potential Impact of Physical Activity

Atherosclerosis, a complex cardiovascular disease, is a leading cause of mortality and morbidity worldwide. Oxidative stress and inflammation are both involved in the development of atherosclerotic plaque as they increase the biological processes associated with this pathology, such as endothelial dysfunction and macrophage recruitment and adhesion. Atherosclerotic plaque rupture leading to major ischemic events is the result of vulnerable plaque progression, which is a result of the detrimental effect of oxidative stress and inflammation on risk factors for atherosclerotic plaque rupture, such as intraplaque hemorrhage, neovascularization, and fibrous cap thickness. Thus, both are key targets for primary and secondary interventions. It is well recognized that chronic physical activity attenuates oxidative stress in healthy subjects via the improvement of antioxidant enzyme capacities and inflammation via the enhancement of anti-inflammatory molecules. Moreover, it was recently shown that chronic physical activity could decrease oxidative stress and inflammation in atherosclerotic patients. The aim of this review is to summarize the role of oxidative stress and inflammation in atherosclerosis and the results of therapeutic interventions targeting them in both preclinical and clinical studies. The effects of chronic physical activity on these two key processes are then reviewed in vulnerable atherosclerotic plaques in both coronary and carotid arteries.

Association between carotid artery plaque inflammation and brain MRI

PURPOSE

To explore the association between presence of inflammatory cells in the carotid plaques surgically treated and brain MRI findings.

MATERIAL AND METHODS

Forty consecutive patients were prospectively analyzed. Brain MRI was performed with a 1.5 Tesla scanner and infacts (lacuna and non-lacunar) pertinence of the anterior circulation were recorded. All patients underwent carotid endarterectomy "en bloc"; carotid plaques histological sections were prepared and immuno-cytochemical analysis was performed to characterize and quantify the presence of inflammatory cells. ROC curve analysis, Pearson Rho correlation and Mann-Whitney test were applied.

RESULTS

The immuno-cytochemical analysis demonstrated that plaques of symptomatic patients (stroke\TIA; n = 25) had more inflammatory cells, mainly macrophages (CD68) compared with plaques of patients without symptoms (Mann-Whitney = P < 0.001, ROC curve area = 0.901). Correlation analysis showed a statistically significant association between the number of brain non-lacunar infarcts and the entity of macrophages (P < 0.001); whereas no association with lacunar infarcts (P = 0.1934) was found.

CONCLUSION

Results of this preliminary study suggest that the presence and amount of inflammatory cells within carotid artery plaque is associated with cerebrovascular events and with the number of MRI brain detectable infarct.

Specific matrix metalloproteinases and calcification factors are associated with the vulnerability of human carotid plaque

The rupture of atherosclerotic plaque provokes the majority of acute cerebrovascular events. Studies have demonstrated that various matrix metalloproteinases (MMPs) may promote atherosclerotic plaque progression and rupture. However, results have been incongruous and the mechanisms of this remain obscured. Therefore, in the current study, carotid plaques were characterized by assessing the levels of MMPs and calcification factors, and evaluating their association with plaque vulnerability. Human carotid plaques were obtained from carotid endarterectomies, and classified into stable and vulnerable groups by ultrasonography and histological analyses. The mRNA and protein levels of MMPs, vascular endothelial growth factor (VEGF), bone sialoprotein 2 (BSP) and osteopontin were investigated by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. Immunohistochemistry was used to localize MMP-2 and MMP-14 in stable and vulnerable plaques. The activation of various associated signaling pathways was also investigated using western blotting. The mRNA levels of MMP-2, -7, -9 and -14 were elevated in vulnerable plaques, among which expression of MMP-2 and -14 were the highest. Consistent with the mRNA levels, the protein levels of MMP-2 and -14 were also elevated. Immunohistochemistry also demonstrated positive staining of MMP-2 and MMP-14 in vulnerable plaques. Factors that indicate neovascularization and calcification, including VEGF and BSP, were concurrently elevated in vulnerable plaques. In addition, the protein levels of extracellular regulated kinase (ERK) and protein kinase C (PKC) were upregulated in vulnerable plaques. The current study provides novel insights into the MMP profiles of vulnerability plaques, and may assist in the development of novel methods for the diagnosis of plaque vulnerability and the prevention of plaque rupture.

Prognostic value of high-resolution magnetic resonance imaging in evaluating carotid atherosclerotic plaque in patients with ischemic stroke

BACKGROUND

Ischemic stroke (IS) is a devastating occurrence affecting millions worldwide. This study aimed to evaluate the prognostic value of high-resolution magnetic resonance imaging (HRMRI) in assessing carotid atherosclerotic plaque in IS patients.

METHODS

Between January 2013 and March 2015, 338 IS patients were recruited for the investigative purposes of the study. All participants of the study underwent an HRMRI inspection procedure after being admitted into the hospital. During this study, we systematically analyzed and measured various types of fibrous caps, lipid compositions, and plaque lipid ratios. Univariate and multivariate logistic regression analyses were performed for predicting prognosis of IS patients. A receiver-operating characteristic (ROC) curve was employed to determine the accuracy of the IS prognosis.

RESULTS

The percentage of type I fibrous caps exhibited significant decrease, while the percentage of type III fibrous caps, lipid compositions, and lipid ratios all displayed increase. The results of the univariate analysis indicated that age, hypertension, hyperlipidemia, treatment regimens, fibrous cap type, plaque type, lipid composition, and lipid ratio shared a correlation in regards to the poor prognosis of IS patients. Multivariate logistic regression analysis demonstrated that the prognosis of IS patients was not necessarily dependent on fibrous cap type, plaque type, or age. ROC curves revealed that the HRMRI possessed a strong predicative ability in relation to the identification of the prognosis of IS patients through factors such as type of plaque and fibrous caps determination.

CONCLUSION

Our study conclusively intimated the promise of HRMRI as an evaluative tool for the determination of carotid atherosclerotic plaques in patients with IS.

Fibrinolysis inhibitors in plaque stability: a morphological association of PAI-1 and TAFI in advanced carotid plaque

Essentials Fibrinolysis inhibitors are localized in advanced atheroma by immunohistology of endarterectomies. Neovascular endothelium/neocapillaries show thrombin-activatable fibrinolysis inhibitor (TAFI). Macrophage areas show free plasminogen activator inhibitor (PAI-1), notably in the vulnerable part. Free PAI-1 and TAFI stabilize active plaque area by inhibition of fibrinolysis and inflammation.

SUMMARY

Background Fibrinolysis plays an important role in destabilization of atherosclerotic plaques and is tightly regulated by specific inhibitors. Objective The fibrinolysis inhibitors plasminogen activator inhibitor type-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) were quantified and described in the morphological context of advanced carotid plaques American Heart Association VI-VIII to elucidate their role in plaque stability. Methods Immunohistochemistry in serial sections along the longitudinal axis of endarterectomies from patients with symptomatic carotid stenosis (n = 19) were studied using an antibody specific for free PAI-1 (I205), an antibody with high affinity for TAFI/TAFIa (CP17) and established antibodies for smooth muscle cells (α-actin), endothelial cells (von Willebrand factor [VWF]), macrophages (CD68) and platelets (CD42). Results PAI-1 and TAFI show a specific distribution in these advanced plaques with a maximum corresponding to the internal carotid artery (ICA). Free PAI-1 was mainly detected in macrophages and in intravascular thrombi, and TAFI in endothelial cells (ECs) but also macrophages. The one-way ANOVA analysis with Bonferroni's correction showed a significant increase of macrophages and ECs, TAFI and PAI-1 in areas with high neovascularization in endarterectomy sections corresponding to ICA. High Spearman factors for TAFI, PAI-1 and VWF indicate neovascularization as the main source of plasma proteins, transported by platelets into the atheroma (PAI-1) or expressed by ECs (TAFI). CD68 was highly associated with VWF, PAI-1 and especially TAFI, underlining the role of macrophages in fibrinolytic activity and inflammation. Conclusion The abundance of free PAI-1 and TAFI in the plaque may inhibit plasmin generation and thereby counteract plaque destabilization by fibrinolysis, cell migration and inflammation.

Smooth muscle cell-specific deletion of Col15a1 unexpectedly leads to impaired development of advanced atherosclerotic lesions

Atherosclerotic plaque rupture with subsequent embolic events is a major cause of sudden death from myocardial infarction or stroke. Although smooth muscle cells (SMCs) produce and respond to collagens in vitro, there is no direct evidence in vivo that SMCs are a crucial source of collagens and that this impacts lesion development or fibrous cap formation. We sought to determine how conditional SMC-specific knockout of collagen type XV (COL15A1) in SMC lineage tracing mice affects advanced lesion formation given that 1) we have previously identified a Col15a1 sequence variant associated with age-related atherosclerosis, 2) COL15A1 is a matrix organizer enhancing tissue structural integrity, and 3) small interfering RNA-mediated Col15a1 knockdown increased migration and decreased proliferation of cultured human SMCs. We hypothesized that SMC-derived COL15A1 is critical in advanced lesions, specifically in fibrous cap formation. Surprisingly, we demonstrated that SMC-specific Col15a1 knockout mice fed a Western diet for 18 wk failed to form advanced lesions. SMC-specific Col15a1 knockout resulted in lesions reduced in size by 78%, with marked reductions in numbers and proliferating SMCs, and lacked a SMC and extracellular matrix-rich lesion or fibrous cap. In vivo RNA-seq analyses on SMC Col15a1 knockout and wild-type lesions suggested that a mechanism for these effects is through global repression of multiple proatherogenic inflammatory pathways involved in lesion development. These results provide the first direct evidence that a SMC-derived collagen, COL15A1, is critical during lesion pathogenesis, but, contrary to expectations, its loss resulted in marked attenuation rather than exacerbation of lesion pathogenesis.NEW & NOTEWORTHY We report the first direct in vivo evidence that a smooth muscle cell (SMC)-produced collagen, collagen type XV (COL15A1), is critical for atherosclerotic lesion development. SMC Col15a1 knockout markedly attenuated advanced lesion formation, likely through reducing SMC proliferation and impairing multiple proatherogenic inflammatory processes.

Sex Differences in Prevalence of and Risk Factors for Carotid Plaque among Adults: A Population-based Cross-Sectional Study in Rural China

Although the associations between carotid plaque and cardiovascular disease risk factors have been identified in previous studies, there is limited information on sex-related differences in factors associated with the development of carotid plaque. We aimed to determine sex differences in the prevalence of carotid plaque and associated risk factors in rural China. A total of 3,789 subjects aged ≥45 years without history of stroke or cardiovascular disease were recruited to the study. B-mode ultrasonography was performed to determine the presence of carotid plaque. The mean age of male subjects was greater than that of female subjects. In addition, there was a higher prevalence of carotid plaque in men than in women (50.1% vs. 35.5%; P < 0.001) irrespective of age group, education level, and presence of risk factors. Older age, hypertension, diabetes mellitus, and high concentrations of low-density lipoprotein cholesterol were pronouncedly associated with the risk of carotid plaque in both men and women. These findings suggest that it is vital for physicians to be aware that conventional risk factors and other related factors are of equal importance among rural residents in China; patients should thus be treated accordingly so that reduce the burden of stroke and cardiovascular disease.

Age-associated changes in human carotid atherosclerotic plaques

Little is known about changes in carotid plaque morphology during aging and the possible impact on cardiovascular events. Only few studies addressed so far age-related modifications within atherosclerotic lesions. Therefore, in this work we endeavored to summarize the current knowledge about changing of plaque composition in elderly. The data from hitherto existing studies confirm that atherosclerotic plaques undergo distinct alternations with advanced age. However, the results are often ambiguous and the changes do not seem to be as disastrous as expected. Interestingly, none of the studies could definitely evidence increased plaque vulnerability with advanced age. Nevertheless, based on the previous work showing decrease in elastin fibers, fibroatheroma, SMCs, overall cellularity and increase in the area of lipid core, hemorrhage, and calcification, the plaque morphology appears to transform toward unstable plaques. Otherwise, even if inflammatory cells often accumulate in plaques of younger patients, their amount is reduced in the older age and so far no clear association has been observed between thin fibrous cap and aging. Thus, the accurate contribution of age-related changes in plaque morphology to cardiovascular events has yet to be elucidated. KEY MESSAGES Composition of carotid atherosclerotic lesions changes during aging. These alternations are however, just moderate and depend upon additional variables, such as life style, accompanying disease, genetics, and other factors that have yet to be determined. Based on the current data, the age-associated plaque morphology seems to transform toward vulnerable plaques. However, the changes do not seem to be as disastrous as expected.

Assessment of the vulnerable carotid atherosclerotic plaque using contrast-enhanced ultrasonography

Carotid atherosclerosis represents a primary cause for cerebrovascular ischemic events and its contemporary management includes surgical revascularization for moderate to severe symptomatic stenoses. However, the role of invasive therapy seems to be questioned lately for asymptomatic cases. Numerous reports have suggested that the presence of neovessels within the atherosclerotic plaque remains a significant vulnerability factor and over the last decade imaging modalities have been used to identify intraplaque neovascularization in an attempt to risk-stratify patients and offer management guidance. Contrast-enhanced ultrasonography of the carotid artery is a relatively novel diagnostic tool that exploits resonated ultrasound waves from circulating microbubbles. This property permits vascular visualization by producing superior angiography-like images, and allows the identification of vasa vasorum and intraplaque microvessels. Moreover, plaque neovascularization has been associated with plaque vulnerability and ischemic symptoms lately as well. At the same time, attempts have been made to quantify contrast-enhanced ultrasonography signal using sophisticated software packages and algorithms, and to correlate it with intraplaque microvascular density. The aim of this review was to collect all recent data on the characteristics, performance, and prognostic role of contrast-enhanced ultrasonography regarding carotid stenosis management, and to produce useful conclusions for clinical practice.

Factors Significantly Associated With the Increased Prevalence of Carotid Atherosclerosis in a Northeast Chinese Middle-aged and Elderly Population: A Cross-sectional Study

Carotid atherosclerosis is associated with many serious cardiovascular diseases; hence, it is necessary to identify factors related to its occurrence in order to develop preventive and therapeutic strategies. This study was conducted to identify risk factors associated with carotid atherosclerosis among the population residing in Northeast China.This epidemiological survey was conducted in a representative group of relatively healthy community residents. All participants answered questions about their medical histories and underwent physical examination, blood biochemical analysis, and ultrasonography examinations of their necks and abdomens. The prevalence rates of carotid atherosclerosis under different factors and conditions were then analyzed.The results of this study showed that age, gender, and diabetes significantly affected the prevalence of carotid atherosclerosis in this Northeast Chinese population. In addition, gender-based subgroup analysis revealed additional factors correlated with the prevalence of carotid atherosclerosis in men or women, although their correlations were not significant in the overall population. While high serum TC and LDL-C levels were risk factors for carotid atherosclerosis in men, it showed no clear correlation with the prevalence of carotid atherosclerosis in women. In contrast, the prevalence of carotid atherosclerosis in female participants with high serum TG level, hypertension, obesity and nonalcoholic fatty liver disease were higher than that of the control population, a trend not observed in male participants.Older age, male sex, and diabetes were independently associated with increased risk of carotid atherosclerosis in Northeast China. These findings could lead to improved screening for carotid atherosclerosis for better disease management.

A Microscopic and Biomarker Evaluation of Embolic Filter Debris Collected During Carotid Artery Stenting

PURPOSE

To evaluate and characterize debris retrieved from the cerebral embolic protection devices (EPDs) used during carotid artery stenting (CAS) and compare debris size, volume, tissue types, cellular composition, and protein biomarker expression in symptomatic and asymptomatic patients.

METHODS

Distal protection filters were retrieved from 22 consecutive patients (mean age 71.6 years, range 52-85; 16 men) undergoing elective CAS between July 2012 and February 2014 for >70% internal carotid artery stenosis (mean 85.4% ± 10.3%). Six patients were symptomatic. The debris within each EPD was visually characterized using stereomicroscopy and then processed for histology and immunohistochemistry. Biomarkers were immunohistochemically measured to evaluate plaque stability [matrix metalloproteinase-9 (MMP-9)], inflammation [glycoprotein CD68 and interleukin-6 (IL-6)], or phenotype [smooth muscle (SM)-actin and type IV collagen]. The immunohistochemical results were measured using semiquantitative grading criteria based on both staining intensity and distribution in the samples.

RESULTS

Macroscopic debris was visible in 5/22 EPDs; 3 of the 5 filters came from symptomatic patients. Microscopic debris was detected in all filters and ranged in size from 0.01 to 8.57 mm(2). Debris consisted of calcified, fibrous, and necrotic tissue, as well as fibrin and foam cells with no significant difference between the symptomatic and asymptomatic groups. There was no association between the degree or type of embolic material and stenosis severity, carotid tortuosity, calcium grade, soft plaque, or arch type. Symptomatic patients had a larger volume of debris (8.24 vs 0.58 mm(3), p<0.01), mean particle size (1.30 vs 0.32 mm(2), p<0.001), and expression of biomarkers IL-6 (2.17 vs 0.81, p<0.05), CD68 (2.00 vs 0.38, p<0.01), SM-actin (1.00 vs 0.25, p=0.055), type IV collagen (1.17 vs 0.25,p=0.082), and MMP-9 (1.00 vs 0.06, p<0.05).

CONCLUSION

Histological analysis revealed particulate embolization in all EPDs used during CAS. Symptomatic patients had a larger volume of embolic debris, mean particle size, and the biomarkers associated with inflammation, necrotic core, and diminished fibrous cap.

Histone acetylation and methylation significantly change with severity of atherosclerosis in human carotid plaques

BACKGROUND

The aim of the study was to analyze histone acetylation, methylation, and the expression of their corresponding transferases in atherosclerotic plaques of patients with carotid artery stenosis.

METHODS

Atherosclerotic tissue from our biobank (n=80) was divided into various segments covering all plaque stages and classified according to the American Heart Association. The plaques were assigned to early (types I-III) or advanced (types V-VII) stage group of atherosclerosis. Ten healthy carotid arteries from transplant donors served as controls. The expression of histone acetyltransferases (GNAT group: GCN5L, P300/CBP group: P300, MYST group: MYST1 and MYST2) and histone methyltransferases (H3K4: MLL2/4, SET7/9, and hSET1A; H3K9: SUV39H1, SUV39H2, ESET/SETDB1, and EHMT1; H3K27: EZH2 and G9a) was analyzed by SYBR-green-based real-time polymerase chain reaction. Histone acetylation/methylation in the cells within atherosclerotic plaques was determined by immunohistochemistry.

RESULTS

Increased histone acetylation was observed on H3K9 and H3K27 in smooth muscle cells (SMCs) in advanced atherosclerotic lesions compared to healthy vessels (P=.002 and .034). H3K9 acetylation in SMCs and macrophages was associated with plaque severity of atherosclerosis (P=.048 and <.001). Expression of GCN5L and MYST1 also correlated with the severity of atherosclerosis (P<.001). Methylation of H3K9 and H3K27 was significantly reduced in atherosclerotic plaques in SMCs and inflammatory cells (P<.001 and .026). Methylation on H3K4 was significantly associated with the severity of atherosclerosis. Expression of methyltransferase MLL2/4 was increased in advanced stages of atherosclerosis (P<.001).

CONCLUSIONS

Histone acetylation and methylation seem to play a decisive role in atherosclerosis, showing significant differences between healthy vessels and vessels at different stages of atherosclerosis.

A reduced risk of stroke with lithium exposure in bipolar disorder: a population-based retrospective cohort study

OBJECTIVES

The risk of stroke is increased in patients with bipolar disorder. Lithium exhibits neuroprotective effects but the association between lithium use and the risk of stroke is unknown.

METHODS

A population-based retrospective cohort study was conducted by utilizing the National Health Insurance Research Database in Taiwan. Subjects who had first been diagnosed with bipolar disorder between 2001 and 2006 were identified. A propensity score (PS) for receiving lithium was calculated with variables of age, gender, and comorbidities. The patients with bipolar disorder receiving lithium within the period from diagnosis through to December 2011 were designated as the lithium group (n = 635). A 1:2 ratio was used to select PS-matched subjects with bipolar disorder without lithium use (n = 1,250). Multivariate Cox proportional hazards regression models were used to explore the association, rather than causal inference, of lithium exposure and the risk of stroke.

RESULTS

Of the 1,885 subjects, 86 (4.6%) experienced stroke, including 2.8% of the lithium group and 5.4% of the non-lithium group. Lithium use was associated with a significantly reduced risk of stroke [hazard ratio (HR) = 0.39, 95% confidence interval (CI): 0.22-0.68]. Reduced risks of stroke were also associated with the highest cumulative lithium dose [≥720 defined daily dose (DDD), HR = 0.25, 95% CI: 0.10-0.59], the longest cumulative exposure period (≥720 days, HR = 0.20, 95% CI: 0.06-0.64), and the highest exposure rate (≥2 DDD/day, HR = 0.39, 95% CI: 0.21-0.70).

CONCLUSIONS

Lithium use was significantly related to a reduced risk of stroke in patients with bipolar disorder.

Fe(III) distribution varies substantially within and between atherosclerotic plaques

PURPOSE

Vulnerable atherosclerotic plaques are structurally weak and prone to rupture, presumably due to local oxidative stress. Redox active iron is linked to oxidative stress and the aim of this study was to investigate the distribution of Fe(III) in carotid plaques and its relation to vulnerability for rupture.

METHODS

Atherosclerotic plaques from 10 patients (three asymptomatic and seven symptomatic) were investigated. Plaque vulnerability was classified using ultrasound and immunohistochemistry and correlated to Fe(III) measured by electron paramagnetic resonance spectroscopy.

RESULTS

Large intra-plaque Fe(III) variations were found. Plaques from symptomatic patients had a higher Fe(III) concentration as compared with asymptomatic plaques (0.36 ± 0.21 vs. 0.06 ± 0.04 nmol Fe(III)/mg tissue, P < 0.05, in sections adjoining narrowest part of the plaques). All but one plaque from symptomatic patients showed signs of cap rupture. No plaque from asymptomatic patients showed signs of cap rupture. There was a significant increase in cap macrophages in plaques from symptomatic patients compared with asymptomatic patients (31 ± 11% vs. 2.3 ± 2.3%, P < 0.01).

CONCLUSION

Fe(III) distribution varies substantially within atherosclerotic plaques. Plaques from symptomatic patients had significantly higher concentrations of Fe(III), signs of cap rupture and increased cap macrophage activity.

Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

SIGNIFICANCE

Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells.

RECENT ADVANCES

Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results.

CRITICAL ISSUES

NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke.

FUTURE DIRECTIONS

Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke.

Long-term effects of maternal undernutrition on offspring carotid artery remodeling: role of miR-29c

The purpose of this study was to examine the hypothesis that excess maternal glucocorticoids in response to maternal undernutrition programs the expression of extracellular matrix (ECM) components potentially by miR-29c. We measured the expression of mRNA (qRT-PCR) and protein (Western blot) for collagen 3A1, collagen 4A5 and matrix metalloproteinase 2 (MMP2) in offspring carotid arteries from three groups of dams: 50% food-restricted in latter half of gestation [maternal undernutrition (MUN)], MUN dams who received metyrapone (MET) (500 mg/ml ) in drinking water from day 10 of gestation to term, and control dams fed an ad libitum diet. The expression of miR-29c was significantly decreased at 3 weeks, 3 months and 9 months in MUN carotid arteries, and these decreases in expression were partially blocked by treatment of dams with MET. The expression pattern of ECM genes that are targets of miR-29c correlated with miR-29c expression. Expression of mRNA was increased for elastin (ELN) and MMP2 mRNA in 3-week MUN carotids; in 9-month carotids there were also significant increases in expression of Col3A1 and Col4A5. These changes in mRNA expression of ECM genes at 3 weeks and 9 months were blocked by MET treatment. Similarly, the expression of ELN and MMP2 proteins at 3 weeks were increased in MUN carotids, and by 9 months there were also increases in expression of Col3A1 and Col4A5, which were blocked by MET in MUN carotids. Overall, the results demonstrate a close correlation between expression of miR-29c and the ECM proteins that are its targets thus supporting our central hypothesis.

Interleukin 23 levels are increased in carotid atherosclerosis: possible role for the interleukin 23/interleukin 17 axis

BACKGROUND AND PURPOSE

Interleukin (IL)-23 is a cytokine in the IL-12 family, mainly produced by antigen-presenting cells with a central role in inflammation. We hypothesize that IL-23 is also important in atherogenesis and investigate this in a population with carotid atherosclerosis.

METHODS

Plasma levels of IL-23 were measured in patients with carotid artery stenosis and in healthy controls. The mRNA levels of IL-23 and its receptor, IL-23R, were measured in atherosclerotic plaques, nonatherosclerotic vessels, peripheral blood mononuclear cells, and plasmacytoid dendritic cells.

RESULTS

Our findings were as follows: (1) patients with carotid atherosclerosis (n=177) had significantly raised plasma levels of IL-23 when compared with healthy controls (n=24) with particularly high levels in those with the most recent symptoms. (2) mRNA levels of IL-23 and IL-23R were markedly increased in carotid plaques (n=68) when compared with nonatherosclerotic vessels (n=8-10). Immunostaining showed colocalization to plaque macrophages. (3) Patients with carotid atherosclerosis had increased mRNA levels of both IL-23 and IL-23R in plasmacytoid dendritic cells, but not in peripheral blood mononuclear cells. (4) IL-23 increased IL-17 release in monocytes and particularly in peripheral blood mononuclear cells from patients with carotid atherosclerosis, but not in cells from healthy controls. (5) IL-23 gave a prominent tumor necrosis factor release in monocytes from patients with carotid atherosclerosis but not in cells from healthy controls. (6) High plasma levels of IL-23 were associated with increased mortality during follow-up.

CONCLUSIONS

We have shown an association between IL-23 and disease progression in patients with carotid atherosclerosis, potentially involving IL-17-related mechanisms.

Lack of association between carotid artery stenosis and stroke or myocardial injury after noncardiac surgery in high-risk patients

BACKGROUND

Whether carotid artery stenosis predicts stroke after noncardiac surgery remains unknown. We therefore tested the primary hypothesis that degree of carotid artery stenosis is associated with in-hospital stroke or 30-day all-cause mortality after noncardiac surgery. As carotid artery stenosis is also a marker for cardiovascular disease, our secondary hypothesis was that degree of carotid artery stenosis is associated with postoperative myocardial injury.

METHODS

We included adults who had noncardiac, noncarotid surgery at Cleveland Clinic from 2007 to 2011 and had carotid duplex ultrasound performed either within 6 months before or 1 month after surgery. Internal carotid artery peak systolic velocity (ICA PSV) was used as a measure of carotid artery stenosis severity. A multivariate (i.e., multiple outcomes per patient) generalized estimating equation model was used to assess the association between highest ICA PSV and the composite of stroke and 30-day mortality after adjusting for predefined potentially confounding variables.

RESULTS

Of 2,110 patients included, 112 (5.3%) died within 30 days and 54 (2.6%) suffered postoperative in-hospital stroke. ICA PSV was not associated with this composite outcome (odds ratio of 1.0 [95% confidence interval: 0.99, 1.02] for a 10-unit increase, P = 0.55). ICA PSV was also not associated with postoperative myocardial injury (odds ratio 1.00 [0.99, 1.02], P = 0.49).

CONCLUSIONS

This cohort represents a high-risk population, as carotid duplex examinations were likely prompted by neurological symptoms. There was nonetheless no association between carotid artery stenosis and perioperative stroke or 30-day mortality after noncardiac surgery.

Relationship between lysophosphatidic acid and matrix metalloproteinase-9 plasma concentrations and carotid atheromatous plaque stability in patients with cerebral infarction

Objective:

To investigate the correlation between plasma lysophosphatidic acid (LPA), matrix metalloproteinase (MMP)-9 and carotid atheromatous plaque stability in patients with cerebral infarction.

Method:

Patients with cerebral infarction underwent carotid artery duplex ultrasonography and transcranial Doppler monitoring for detection of microemboli. Patients were stratified by plaque type (no plaque, intima thickening, unstable plaque, stable plaque) and presence or absence of micoremboli. Plasma LPA and MMP-9 were quantified.

Result:

LPA and MMP-9 concentrations were significantly higher and microemboli positivity was significantly more common in patients with unstable plaque ( n = 21) than the other three groups (intima thickening, n = 16; stable plaque n = 41; no plaque; n = 12). There was a significant positive correlation between LPA and MMP-9 concentrations.

Conclusion:

Plasma LPA and MMP-9 concentrations may be useful biomarkers in the clinical identification and prediction of unstable plaque, and in guiding treatment.

Homocysteine and carotid plaque stability: a cross-sectional study in Chinese adults

BACKGROUND AND PURPOSE

This study aimed to explore the possible association of plasma total homocysteine with carotid plaque stability.

METHODS

A cross-sectional study was conducted from 2010 to 2011. A stratified random sample of 2,919 Chinese participants aged 40 years or older was enrolled. Plasma total homocysteine levels were measured and carotid plaques were evaluated by ultrasonography. Logistic regression model was used to analyze the association of homocysteine levels to the progression of carotid plaque development, while adjusting for demographics and vascular risk factors.

RESULTS

The mean level of plasma homocysteine in the subjects was 14.9 µmol/l. Along with increase in homocysteine level, the risk of advanced carotid plaque elevated (odds ratio = 1.28; 95% confidence interval = 1.09-1.51) after adjusting for age, sex, and other potential confounders. Stratified by sex, higher homocysteine level was strongly associated with advanced carotid plaque in men (OR = 1.41; 95% confidence interval = 1.17-1.70), but not in women.

CONCLUSION

The findings suggest that plasma level of homocysteine may be associated with advanced carotid plaque, which constitutes high risks of stroke, in male Chinese adults.

Association between ADAM17 promoter polymorphisms and ischemic stroke in a Chinese population

AIM

Stroke is a leading cause of death and disability worldwide. Most ischemic strokes (IS) are caused by atherosclerosis. Recently, the pivotal role of ADAM17 in atherosclerosis has been thoroughly addressed. However, the association between ADAM17 and IS has not yet been thoroughly explored. The present study therefore aimed to investigate the association between disintegrin and metalloproteinase 17 (ADAM17) gene polymorphisms and the risk of ischemic stroke (IS).

METHODS

The associations between five ADAM17 promoter polymorphisms and the risk of IS were assessed in 342 patients with IS and 296 age-matched healthy individuals in a case-control study.

RESULTS

The allele and genotype frequencies of the ADAM17 polymorphisms (rs11684747, rs11689958, rs12692386, rs55790676 and rs1524668) did not differ significantly between the IS patients and healthy control group subjects. In addition, no significant associations were detected between the ADAM17 haplotypes and IS. The mean intima-media thickness in the IS patients was not associated with the ADAM17 polymorphisms. When the IS patients were stratified according to their OCSP classification, the genotype frequencies of the ADAM17-rs1524668 polymorphism exhibited a significant association with the PACI subtype of IS. Moreover, the ADAM17-rs12692386 A＞G polymorphism was found to be associated with a higher ADAM17 mRNA expression.

CONCLUSIONS

The SNPs in the ADAM17 promoter region do not appear to be major contributors to the pathogenesis of IS. However, the rs12692386 G ADAM17 allele is correlated with a higher expression of ADAM17 mRNA, which may play a role in increasing inflammation in IS patients. Furthermore, the ADAM17-rs1524668 polymorphism is linked to a higher risk of PACI-type stroke, confirming the role of ADAM17 in the pathophysiology of PACI, with potentially important therapeutic implications.