Assessment of plaque vulnerability in carotid atherosclerotic plaques using contrast-enhanced ultrasound.

Background: Atherosclerotic carotid plaques are one of the most important causes of stroke. Apart from the severity of stenosis, there are certain plaque characteristics such as neovascularization and, surface ulceration which makes a plaque vulnerable. This study was performed to study the plaque characteristics using contrast-enhanced ultrasound (CEUS) and evaluate their association with presence of ischemic cerebrovascular symptoms in these patients. Methods: This study included patients presenting at a tertiary care center, having carotid plaques causing >60% stenosis. CEUS was performed for assessment of intraplaque neovascularity and plaque surface characteristics. These plaque features were then evaluated for their association with presence of ischemic cerebrovascular symptoms in patients. Results: Sixty plaques were studied in 50 patients. Thirty-two plaques were associated with ischemic cerebrovascular symptoms. On CEUS, intraplaque neovascularization was seen in 38 of the 60 plaques studied (63.3%). There was statistically significant association of intraplaque neovascularity and plaque surface characteristics with presence of ischemic cerebrovascular symptoms. Conclusion: CEUS allows better characterization of plaque surface characteristics and also depicts plaque neovascularization, which helps in determining the plaque vulnerability. It should be used as an adjunct to ultrasound and doppler assessment of carotid plaques.

Histopathological and ultrastructural study of carotid atherosclerotic plaques: a study of four cases.

To clarify the characteristics and origin of the cellular components in atherosclerosis, carotid atherosclerotic plaques (CAPs) of four patients were studied by light microscopy using hematoxylin-eosin, Congo red and alpha-smooth-muscle actin stains, and by transmission electron microscopy of different regions of CAPs. By light microscopy, CAPs were composed of 1) a fibrous cap; 2) an atherosclerotic core presenting focal fibrosis, neovascularization, hemorrhage, necrosis, chondrification and ossification; and 3) a basal band composed of a hyperplasic pseudo-media and affected tunica media. Ultrastructurally, the CAPs contained a diversity of cells including fibroblasts, myofibroblasts, osteochondrocytes, vascular smooth-muscle cells, foam cells and other myoid cells characterized by varied features of the above mentioned cells. The results indicated that CAPs were derived from a proliferation of multipotential mesenchymal stem cells, leading to the presence of degenerated foam cells and lipid-laden cells.

High-Frame Rate Vector Flow Imaging Technique: Initial Application in Evaluating the Hemodynamic Changes of Carotid Stenosis Caused by Atherosclerosis.

Objective: To investigate the value of high-frame rate vector flow imaging technique (V flow) in evaluating the hemodynamic changes of carotid stenosis caused by atherosclerotic plaques. Methods and Materials: In this prospective study, patients with stenosis rate (diameter) ≥30% caused by carotid atherosclerotic plaques were included. Degrees of carotid stenosis were graded according to North American Symptomatic Carotid Endarterectomy Trial criteria: moderate (30-69%) or severe (70-99%). Mindray Resona 7s ultrasound machine with a linear array transducer (3-11 MHz) was used for ultrasound examinations. The mean WSS value of carotid arteries was measured at the proximal, narrowest region and distal of carotid stenosis. The mean WSS values were correlated with peak systolic velocity (PSV) measured by color Doppler flow imaging and stenosis degree detected by digital subtraction angiography (DSA). The vector arrows and flow streamline detected by V flow dynamic imaging were analyzed. Imaging findings of DSA in carotid arteries were used as the gold standard. Results: Finally, 51 patients were included. V flow measurements were performed successfully in 17 patients (100%) with moderate-grade stenosis and in 30 patients (88.2%) with severe-grade stenosis. Dynamic V flow imaging showed yellow or red vectors at the stenotic segment, indicating fast speed blood flow (up to 260.92 cm/s). Changes of streamlines were detected in the stenotic segment. The mean WSS value measured at the narrowest region of the carotid artery had a moderately positive correlation with stenosis degree (r = 0.58, P < 0.05) and PSV value (r = 0.54, P < 0.05), respectively. Significant difference was detected in mean WSS value at the narrowest region of the carotid artery between severe carotid stenosis (1.47 ± 0.97 Pa) and moderate carotid stenosis (0.96 ± 0.44 Pa) (P < 0.05). Conclusion: The hemodynamic changes detected by V flow of the carotid stenosis might be a potential non-invasive imaging tool for assessing the degree of carotid stenosis.

Bioinformatics analysis reveals the landscape of immune cell infiltration and immune-related pathways participating in the progression of carotid atherosclerotic plaques.

Atherosclerosis is a systemic disease associated with inflammatory cell infiltration and activation of immune-related pathways. In our study, we aimed to uncover immune-related changes and explore novel immunological features in the development of carotid atherosclerotic plaques. First, we applied integrated bioinformatics methods, including CIBERSORT and gene set enrichment analysis (GSEA). The gene expression matrices GSE28829, GSE41571, and GSE43292 were obtained from the Gene Expression Omnibus (GEO) dataset. After a series of data pre-processing steps, the resulting combined expression matrices were analysed using the CIBERSORT, GSEA, and Cluster Profiler packages. After the comparison and analysis between the carotid atherosclerotic plaques in the early and advanced stages, we discovered that there is a higher percentage of activated memory CD4 T cells and a lower percentage of resting memory CD4 cells in advanced-stage plaques. Moreover, activation of memory CD4 T cells can promote the development of carotid atherosclerotic plaques. Additionally, FOXP3+ Treg cell maturation can also participate in the progression of carotid plaques.

Symptomatic Carotid Atherosclerotic Plaques Are Associated With Increased Infiltration of Natural Killer (NK) Cells and Higher Serum Levels of NK Activating Receptor Ligands.

A wide array of immune cells, including lymphocytes, is known to be present and to play a pathogenetic role in atherosclerotic lesions. However, limited information is currently available regarding the presence of Natural Killer (NK) cell subsets within vessel plaque, and more in general, regarding their role in human atherosclerosis. We evaluated the distribution of NK cells in human carotid atherosclerotic plaques, dissecting asymptomatic and symptomatic patients (identified as affected by stroke, transient ischemic attack, or amaurosis fugax within 6 months) with the aim of shedding light on the putative contribution of NK cells to the pathogenic process that leads to plaque instability and subsequent clinical complications. We observed that carotid plaques were consistently infiltrated by NK cells and, among them, CD56brightperforinlow NK cells were abundantly present and displayed different markers of tissue residency (i.e., CD103 CD69 and CD49a). Interestingly, carotid atherosclerotic plaques of symptomatic patients showed a higher content of NK cells and an increased ratio between CD56brightperforinlow NK cells and their CD56dimperforinhigh counterpart. NK cells isolated from plaques of symptomatic patients were also stronger producers of IFN-γ. Analysis of the expression of NK activating receptor ligands (including MICA/B, ULBP-3, and B7-H6) in atherosclerotic carotid plaques revealed that they were abundantly expressed by a HLA-DR+CD11c+ myeloid cell population resident in the plaques. Remarkably, sera of symptomatic patients contained significant higher levels of soluble ligands for NK activating receptors. Our observations indicate that CD56bright NK cells accumulate within human atherosclerotic lesions and suggest a possible contribution of NK cells to the process determining plaque instability.

Value of superb micro-vascular imaging in predicting ischemic stroke in patients with carotid atherosclerotic plaques.

BACKGROUND: Unstable carotid atherosclerotic plaques are prone to cause ischemic stroke. Contrast-enhanced ultrasound (CEUS) is the primary method of assessing plaque stability, but CEUS cannot be a method for screening for unstable plaque. The emergence of superb micro-vascular imaging (SMI) offers the possibility of clinically screening for unstable plaque. AIM: To investigate the value of SMI in predicting ischemic stroke in patients with carotid atherosclerotic plaques. METHODS: Patients with carotid atherosclerotic plaques (luminal stenosis of 50%-70%) were enrolled into the present study. All patients received conservative medication. The patient's clinical baseline data, serological data, CEUS and SMI data were analyzed. All patients underwent a 3-year follow-up. The follow-up endpoint was the occurrence of ischemic stroke and patients were divided into stroke group and non-stroke group according to whether the prognosis occurred or not. Subsequently, the difference in clinical data was compared, the correlation of SMI and CEUS was analyzed, and multiple Cox regression and receiver operating characteristic curve were applied to investigate the value of SMI and CEUS in predicting cerebral arterial thrombosis in three years. RESULTS: In this study, 43 patients were enrolled in the stroke group and 82 patients were enrolled in the non-stroke group. Cox regression revealed that SMI level (P = 0.013) and enhancement intensity (P = 0.032) were the independent factors influencing ischemic stroke. There was a positive correlation between SMI level and enhancement intensity (r = 0.737, P = 0.000). The area under curve of SMI level predicting ischemic stroke was 0.878. The best diagnostic point was ≥ level II, and its sensitivity and specificity was 86.05% and 79.27%. The area under curve of enhancement intensity predicting ischemic stroke was 0.890. The best diagnostic point was 9.92 db, and its sensitivity and specificity was 88.37% and 89.02%. As the SMI level gradually increased, the incidence of ischemic stroke increased gradually (X 2 = 108.931, P = 0.000). CONCLUSION: SMI can be used as a non-invasive method of screening for unstable plaques and may help prevent ischemic stroke.

H-type hypertension is an important risk factor of carotid atherosclerotic plaques.

AIM: To investigate the association of H-type hypertension with carotid atherosclerotic plaques in Chinese. METHODS: This hospital-based large population study included 13192 patients and all the patients were sequentially recruited between May 2010 and May 2013 at the Health Medical Center of the Chinese PLA General Hospital. The subjects were divided into four groups: the H-type of hypertension group, isolated systolic hypertension, simple homocysteine (Hcy) group, and the control group without hypertension and Hcy. Univariate logistic regression analysis was performed to investigate the association of H-type hypertension with the odds of carotid atherosclerotic plaques. RESULTS: Among the 13192 subjects, there were 9007 (68.28% of all subjects) patients with hyperhomocysteinemia and 3543 patients with H-type hypertension, which was 26.86% of all subjects and 74.45% of hypertension patients. 34.55% of all subjects (4558) had carotid atherosclerotic plaques. The carotid atherosclerotic plaques positive rate among four groups was significantly different (χ(2) = 647.8988, P = 0.000). The carotid atherosclerotic plaques' positive rate of patients with H-type hypertension was 49.31%, which was significantly higher than the other three groups. Univariate logistic regression analysis results indicated that significant correlations exist between high-Hcy hypertension and carotid atherosclerotic plaques. Incidence of carotid atherosclerotic plaques in H-type hypertension patients was 1.63 times that in patients with isolated systolic hypertension. CONCLUSION: H-type hypertension is independently associated with higher risk of carotid atherosclerotic plaques. H-type hypertension and Hcy should be the major intervention measures to decrease the incidence of carotid atherosclerotic plaques as well as the stroke in Health Practice Management.

[Effects of berberine on serum inflammatory factors and carotid atherosclerotic plaques in patients with acute cerebral ischemic stroke].

This study aims to analyze the effect of berberine on serum inflammatory factors and carotid atherosclerotic plaques in ppatients with acute cerebral ischemic stroke(AIS). In the study, 120 patients with AIS were randomly divided into berberine group(n=60) and general group (n=60). The 60 cases in the general group were provided with general therapy according to the latest guidelines of diagnosis and treatment of AIS. The berberine group received berberine 300 mg(tid) in addition to the therapy of the general group. The levels of serum inflammatory factors, the nerve function defect grades and the indexes of carotid atherosclerosis plaques [including the total plaque area(TPA), intima-media thickness(IMT) and the number of unstable carotid atherosclerotic plaques] were measured and compared. The results indicated that the levels of serum inflammatory factors, the NIHSS(national institute of health stroke scales) cores and the indexes of carotid atherosclerosis plaques were not significantly different between the berberine groups of general group, with positive correlation between serum inflammatory factors and NIHSS scores(P<0.05). The levels of serum inflammatory factors and NIHSS scores of the berberine groups on 14 d were significantly lower than those on 1 d(P<0.05). The levels of serum inflammatory factors and NIHSS scores of the berberine group on 14 d were significantly lower than those of the general group(P<0.05). The TPA and the number of unstable carotid atherosclerotic plaques of the berberine groups on 90 d were significantly lower than those of general group, with significant differences(P<0.05). The IMT showed a downward trend, but with significant difference.The mRS(modified rankin scale) scores of the berberine group on 90 d were significantly lower, with a higher rate of short-term favorable prognosis (P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups. This study showed that berberine in addition to the general therapy can significantly lower the levels of serum MIF and IL-6, reduce the degree of carotid atherosclerosis to some extent and improve neurological impairment and the prognosis of patients with AIS.

Expression of the NLRP3 Inflammasome in Carotid Atherosclerosis.

BACKGROUND: The aim of the present study was to investigate NLRP3 inflammasome expression in human carotid atherosclerotic plaques and its relationship to plaque vulnerability. METHODS: Carotid atherosclerotic plaques collected from 30 patients scheduled for carotid endarterectomy (CEA) were subjected to immunohistochemical, mRNA, and protein expression studies. Ten mesenteric arteries from intestinal cancer patients served as controls for the immunohistochemical studies. Twenty individuals who had no carotid stenosis or coronary artery stenosis served as controls for analyzing atherosclerotic risk factors and for enzyme-linked immunosorbent assay (ELISA) studies. Serum samples were collected from all patients to determine interleukin-1ß (IL-1ß) and IL-18 levels. RESULTS: The NLRP3 inflammasome signaling pathway components NLRP3, ASC, caspase-1, IL-1ß, and IL-18 were strongly expressed in carotid atherosclerotic plaques, but not in healthy mesenteric arteries. Immunohistochemical, mRNA, and protein expression studies revealed higher expression levels of NLRP3, ASC, caspase-1, IL-1ß, and IL-18 in unstable compared to stable plaques. The NLRP3 inflammasome was localized in the cytoplasm of macrophages and foam cells and was associated with cholesterol crystal clefts inside and outside of cells. ELISA showed that the serum levels of the cytokines IL-1ß and IL-18 were higher in the CEA group compared to controls. CONCLUSIONS: These results demonstrated for the first time the close relationship between the expression of NLRP3 signaling pathway and human carotid atherosclerotic plaques. NLRP3, ASC, caspase-1, IL-1ß, and IL-18 were associated with plaque vulnerability and atherogenesis. The serum levels of IL-1ß and IL-18 may be useful predictors of atherosclerosis.

Expression of the genes encoding kinin receptors are increased in human carotid atherosclerotic plaques.

There is increasing evidence showing that inflammation occurs in atherosclerosis and contributes to the formation of atherosclerotic plaques. As important inflammatory peptides, kinins are increased in inflammation, eliciting vasodilation, increasing vascular permeability and recruiting inflammatory cells to the injury sites by activating specific receptors, B1 and B2. The two receptors have been reported to increase in inflammation, but their expressions remain to be defined in human carotid atherosclerotic plaques (CAP). In order to assess the gene expression of kinin receptors in human CAP, 47 CAP specimens were collected from patients undergoing endarterectomy and classified into stable and unstable plaque groups, respectively, with 10 mesenteric arteries used as controls. Total mRNA of B1R and B2R was extracted from CAPs and their levels were determined using reverse transcription-polymerase chain reaction. The expression of B1R and B2R mRNA was significantly upregulated in human CAPs compared to the control arteries. In the unstable plaques, the ratios of B1R to the ß-actin mRNA level were significantly increased relative to the stable plaques. However, no notable differences were observed in the ratios of B2R to ß-actin in mRNA expression between the stable and unstable plaques. The present study suggests that kinin-mediated inflammation involves the formation of atherosclerotic plaque and B1R plays an important role in plaque instability, indicating that kinin receptors can be used as potential targets for future therapeutic interventions.