Pathological Quantification of Carotid Artery Plaque Instability in Patients Undergoing Carotid Endarterectomy

Increased Piezo1 expression in myofibroblasts in patients with symptomatic carotid atherosclerotic plaques undergoing carotid endarterectomy: A pilot study

OBJECTIVES

We aimed to investigate Piezo1 expression in myofibroblasts in symptomatic and asymptomatic patients undergoing carotid endarterectomy and its relationship with atherosclerotic plaque formation.

METHODS

This cross-sectional study analyzed carotid plaques of 17 randomly selected patients who underwent carotid endarterectomy from May 2015 to August 2017. In total, 51 sections (the most stenotic lesion, and the sections 5-mm proximal and distal) stained with hematoxylin-eosin and elastica-Masson were examined. Immunohistochemistry was performed using antibodies to Piezo1. The Piezo1 score of a section was calculated semiquantitatively, averaged across 30 randomly selected myofibroblasts in the fibrous cap of the plaque.

RESULTS

Of 17 patients (mean age: 74.2 ± 7.1 years), 15 were men, 9 had diabetes mellitus, and 13 had hypertension. Symptomatic patients had higher mean Piezo1 score than asymptomatic patients (1.78 ± 0.23 vs 1.34 ± 0.17, p < .001). Univariate linear regression analyses suggested an association between plaque rupture, thin-cap fibroatheroma and microcalcifications and the Piezo1 score (p = .001, .008, and 0.003, respectively).

CONCLUSIONS

Increased Piezo1 expression of myofibroblasts may be associated with atherosclerotic carotid plaque instability. Further study is warranted to support this finding.

Quantitative comparison between carotid plaque hardness and histopathological findings: an observational study

Background

Plaque hardness in carotid artery stenosis correlates with cerebral infarction. This study aimed to quantitatively compare plaque hardness with histopathological findings and identify the pathological factors involved in plaque hardness.

Methods

This study included 84 patients (89 lesions) undergoing carotid endarterectomy (CEA) at our institution. Plaque hardness was quantitatively measured immediately after excision using a hardness meter. Collagen and calcification were evaluated as the pathological factors. Collagen was stained with Elastica van Gieson stain, converted to a gray-scale image, and displayed in a 256-step histogram. The median gray-scale median (GSM) was used as the collagen content. The degree of calcification was defined by the hematoxylin–eosin stain as follows: "0:" no calcification, "1:" scattered microcalcification, or "2:" calcification greater than 1 mm or more than 2% of the total calcification. Carotid echocardiographic findings, specifically echoluminance or the brightness of the narrowest lesion of the plaque, classified as hypo-, iso-, or hyper-echoic by comparison with the intima-media complex surrounding the plaque, and clinical data were reviewed.

Results

Plaque hardness was significantly negatively correlated with GSM [Spearman's correlation coefficient: -0.7137 (p < 0.0001)]: the harder the plaque, the higher the collagen content. There were significant differences between plaque hardness and degree of calcification between "0" and "2" (p = 0.0206). For plaque hardness and echoluminance (hypo-iso-hyper), significant differences were found between hypo-iso (p = 0.0220), hypo-hyper (p = 0.0006), and iso-hyper (p = 0.0015): the harder the plaque, the higher the luminance. In single regression analysis, GSM, sex, and diabetes mellitus were significant variables, and in multiple regression analysis, only GSM was extracted as a significant variable.

Conclusions

Plaque hardness was associated with a higher amount of collagen, which is the main component of the fibrous cap. Greater plaque hardness was associated with increased plaque stability. The degree of calcification may also be associated with plaque hardness.

miR-320a targeting RGS5 aggravates atherosclerosis by promoting migration and proliferation of ox-LDL-stimulated vascular smooth muscle cells

ABSTRACT

MicroRNAs (miRNAs) have been implicated in atherosclerosis (AS) progression. Here, we focused on how miR-320a affect AS progression via vascular smooth muscle cells (VSMCs). Oxidized low-density lipoproteins (ox-LDL)-stimulated VSMCs were used as an AS cell model and qRT-PCR was performed to measure miR-320a and RGS5 levels. CCK-8 and wound healing assays were used to detect the viability and migration of VSMCs. Western blotting was used to measure the protein expression levels of PCNA, Bax, and Bcl-2. The interaction of miR-320a and RGS5 was determined by dual-luciferase and RNA pull-down assays. MiR-320a was highly expressed while RGS5 showed low levels of expression in the arterial plaque tissues. Silencing of miR-320a blocked cell viability and migration, inhibited expression of the proliferation-specific protein PCNA in ox-LDL-treated VSMCs, promoted Bax protein expression and inhibited Bcl-2 protein expression. Furthermore, miR-320a was found to exert these effects by inhibiting RGS5 expression. Collectively, miR-320a promoted cell viability, migration, and proliferation while reducing apoptosis of ox-LDL-stimulated VSMCs by inhibiting RGS5.

Osteoid Metaplasia in Femoral Artery Plaques Is Associated With the Clinical Severity of Lower Extremity Artery Disease in Men

Lamellar metaplastic bone, osteoid metaplasia (OM), is found in atherosclerotic plaques, especially in the femoral arteries. In the carotid arteries, OM has been documented to be associated with plaque stability. This study investigated the clinical impact of OM load in femoral artery plaques of patients with lower extremity artery disease (LEAD) by using a deep learning-based image analysis algorithm. Plaques from 90 patients undergoing endarterectomy of the common femoral artery were collected and analyzed. After decalcification and fixation, 4-μm-thick longitudinal sections were stained with hematoxylin and eosin, digitized, and uploaded as whole-slide images on a cloud-based platform. A deep learning-based image analysis algorithm was trained to analyze the area percentage of OM in whole-slide images. Clinical data were extracted from electronic patient records, and the association with OM was analyzed. Fifty-one (56.7%) sections had OM. Females with diabetes had a higher area percentage of OM than females without diabetes. In male patients, the area percentage of OM inversely correlated with toe pressure and was significantly associated with severe symptoms of LEAD including rest pain, ulcer, or gangrene. According to our results, OM is a typical feature of femoral artery plaques and can be quantified using a deep learning-based image analysis method. The association of OM load with clinical features of LEAD appears to differ between male and female patients, highlighting the need for a gender-specific approach in the study of the mechanisms of atherosclerotic disease. In addition, the role of plaque characteristics in the treatment of atherosclerotic lesions warrants further consideration in the future.

Red and White Thrombus Characteristics in Patients Undergoing Carotid Endarterectomy

OBJECTIVE

The study aimed to compare the characteristics of red and white thrombi in patients undergoing carotid endarterectomy.

MATERIAL AND METHODS

The study was conducted in 81 patients with ischemic stroke who underwent carotid endarterectomy for carotid artery stenosis. Carotid plaques were graded by two pathologists. Thrombus materials were divided into two groups: white and red. The parameters of assessment were plaque rupture, lipid core, fibrous cap thickness, inflammation, intraplaque hemorrhage, calcification, necrotic core, and neovascularization. Normally distributed data were evaluated using Mann-Whitney U and Chi-squared tests.

RESULTS

The ratio of white and red thrombus was 19.8% and 80.2%, respectively. Lipid core, plaque rupture, necrotic core, neovascularization, intraplaque hemorrhage, obstruction, and inflammation were observed more in red thrombus, which were statistically significant. Calcification and fibrous cap thickness were not statistically significant in the two groups. Moreover, intimal smooth muscle cells were present in all thrombus types.

CONCLUSION

In our study, we found that red thrombi had more unstable characteristics than white thrombi. Thus, the risk for ischemic cerebrovascular events is more in red thrombi. However, this finding cannot be generalized due to the small number of patients in this study. Therefore, studies involving more patients are needed.

Eicosapentaenoic acid therapy is associated with decreased coronary plaque instability assessed using optical frequency domain imaging

Background

The relationship between eicosapentaenoic acid (EPA) therapy and coronary plaque stability assessed by optical frequency domain imaging (OFDI) has not been thoroughly described.

Hypothesis

EPA therapy is associated with decreased plaque instability in patients undergoing percutaneous coronary intervention (PCI) using OFDI.

Methods

Data on coronary artery plaques from 121 patients who consecutively underwent PCI between October 2015 and July 2018 were retrospectively analyzed. Of these patients, 109 were untreated (no‐EPA group), whereas 12 were treated with EPA (EPA group). Each plaque's morphological characteristics were analyzed using OFDI.

Results

We used 1:4 propensity score matching for patients who received or did not receive EPA therapy before PCI. Baseline characteristics were balanced between both groups (age, sex, body mass index, diabetes mellitus, hypertension, dyslipidemia, chronic kidney disease, smoking, previous PCI or coronary artery bypass grafting, previous myocardial infarction, prior statin use, acute coronary syndrome, hemoglobin A1c level, low‐density lipoprotein cholesterol concentration, triglyceride concentration, and high‐density lipoprotein cholesterol concentration). OFDI data from 60 patients were analyzed in this study. The EPA group had significantly lower mean lipid index (818 ± 806 vs 1574 ± 891) and macrophage grade (13.5 ± 5.9 vs 19.3 ± 7.4) but higher mean minimum fibrous cap thickness (109.2 ± 55.7 vs 81.6 ± 36.4 μm) than the no‐EPA group (P = 0.010, 0.019, and 0.040, respectively). Multiple logistic regression analyses showed that prior EPA use was independently associated with lower lipid index and macrophage grade (P = 0.043 and 0.024, respectively).

Conclusion

This OFDI analysis suggests that EPA therapy is associated with decreased plaque instability in patients undergoing PCI.

Obstructive sleep apnea is associated with increased coronary plaque instability: an optical frequency domain imaging study

Obstructive sleep apnea (OSA) is associated with coronary artery disease (CAD) and with an increased risk for myocardial infarction, stroke or death due to cardiovascular disease. Optical frequency-domain imaging (OFDI) is a useful modality for evaluating the characteristics of atherosclerotic plaque. The purpose of the study was to use OFDI to investigate the association of OSA with coronary plaque characteristics in patients undergoing percutaneous coronary intervention (PCI). We retrospectively analyzed OFDI data for coronary artery plaques from 15 patients with OSA and 35 non–OSA patients treated between October 2015 and October 2018. Plaque morphology was evaluated for 70 lesions, including 21 from patients with OSA and 49 from non–OSA patients. Compared with the non–OSA group, patients with OSA had significantly higher prevalences of thinned cap fibroatheroma (TCFA) (67% vs. 35%, P = 0.014) and microchannels (86% vs. 55%, P = 0.014); a significantly higher mean lipid index (1392 ± 982 vs. 817 ± 699, P = 0.021), macrophage grade (8.4 ± 6.4 vs. 4.8 ± 4.5, P = 0.030), and maximum number of microchannels (1.5 ± 1.0 vs. 0.7 ± 0.7, P = 0.001); and a significantly lower mean minimum fibrous cap thickness (69.4 ± 28.7 vs. 96.1 ± 51.8 μm, P = 0.008). This OFDI analysis suggests that OSA is associated with unstable plaque characteristics in patients with CAD. More intensive medical management for stabilization of coronary atherosclerotic plaque is required in patients with OSA.

P-Selectin Glycoprotein Ligand-1 (PSGL-1) Expressing CD4 T Cells Contribute Plaque Instability in Acute Coronary Syndrome

BACKGROUND

Adhesion molecules have essential roles in the development of atherosclerosis. We investigated whether P-selectin glycoprotein ligand-1 (PSGL-1)-expressing CD4 T cells contribute to plaque instability in acute coronary syndrome (ACS).Methods and Results:We studied the adhesion molecules on CD4 T cells from consecutive patients with ACS treated with thrombus-aspirating device and compared them with healthy controls (n=48 each). Blood, thrombi, and plaque samples from the culprit coronary arteries were collected by thrombus aspiration performed during emergency coronary artery angiography. According to flow cytometry results, peripheral CD4 T cells from ACS patients strongly expressed PSGL-1 and integrin β2 (P<0.05 for both) more than those from controls; culprit coronary arteries contained an abundance of PSGL-1⁺(P<0.001) but not integrin β2⁺CD4 T cells. In addition, immunohistochemical analysis of the thrombus-aspirating device samples revealed numerous PSGL-1⁺CD4 T cells in plaques from the culprit lesions. Results from the selectin-binding assay demonstrated that activated PSGL-1⁺CD4 T cells from ACS patients bound to P- or E-selectin after triggering the T-cell receptor, and adhered to endothelial cells under laminar flow conditions (P<0.05 and P<0.05, respectively), inducing their apoptosis (P<0.01) via activated caspase-3, which correlated with PSGL-1 expression (R=0.788, P=0.021) and was suppressed by application of a PSGL-1-specific antibody (P<0.05).

CONCLUSIONS

PSGL-1 contributed to cytotoxic CD4 T cell homing to the culprit coronary artery and promoted plaque instability in ACS.

Stabilization of symptomatic carotid atherosclerotic plaques by statins: a clinico-pathological analysis

Human and animal studies have revealed a stabilization of atherosclerotic plaques by statins. However, the stabilization of human carotid plaques has not been thoroughly described pathologically. This analysis explored the relationship between statin therapy and plaque stability in carotid endarterectomy (CEA) specimens. We analyzed specimens harvested between May 2015 and February 2017, from 79 consecutive patients presenting with > 70% carotid artery stenoses, of whom 66 were untreated (group 1) and 13 treated (group 2) with a statin. Immunohistochemistry was performed, using an endothelial specific antibody to CD31, CD34 and platelet derived growth factor receptor-β. The prevalence of plaque ruptures (P = 0.009), lumen thrombi (P = 0.009), inflammatory cells (P = 0.008), intraplaque hemorrhages (P = 0.030) and intraplaque microvessels (P < 0.001) was significantly lower in group 2 than in group 1. Among 66 patients presenting with strokes and infarct sizes > 1.0 cm³ on magnetic resonance imaging, the mean infarct volume was significantly smaller (P = 0.031) in group 2 (4.2 ± 2.5 cm³) than in group 1 (8.2 ± 7.1 cm³). The difference in mean concentration of low-density lipoprotein cholesterol between group 1 (121 ± 32 mg/dl) and group 2 (105 ± 37 mg/dl) was non-significant (P = 0.118). This analysis of plaques harvested from patients undergoing CEA suggests that statin therapy mitigates the plaque instability, which, in patients presenting with strokes, might decrease infarct volume.