Fibrous Cap Research Articles

Enhanced Plaque Stabilization Effects of Alirocumab - Insights From Artificial Intelligence-Aided Optical Coherence Tomography Analysis of the Alirocumab for Thin-Cap Fibroatheroma in Patients With Coronary Artery Disease Estimated by Optical Coherence Tomography (ALTAIR) Study.

Proprotein convertase subtilisin/kexin type 9 inhibitors stabilize vulnerable plaque, reducing cardiovascular events. However, manual optical coherence tomography (OCT) analysis of drug efficacy is challenging because of signal attenuation within lipid plaques. Twenty-four patients with thin-cap fibroatheroma were prospectively enrolled and randomized to receive alirocumab (75 mg every 2 weeks) plus rosuvastatin (10 mg/day) or rosuvastatin (10 mg/day) alone. OCT images at baseline and 36 weeks were analyzed manually and with artificial intelligence (AI)-aided software. AI-aided OCT analysis showed significantly greater percentage changes in the alirocumab+rosuvastatin vs. rosuvastatin-alone group in fibrous cap thickness (FCT; median [interquartile range] 212.3% [140.5-253.5%] vs. 88.6% [63.0-119.6%]; P=0.006) and lipid volume (median [interquartile range] -30.8% [-51.8%, -16.6%] vs. -2.1% [-21.6%, 4.3%]; P=0.015). Interobserver reproducibility for changes in minimum FCT and lipid index was relatively low for manual analysis (interobserver intraclass correlation coefficient [ICC] 0.780 and 0.499, respectively), but high for AI-aided analysis (interobserver ICC 0.999 and 1.000, respectively). Agreements between manual and AI-aided OCT analyses of FCT and the lipid index were acceptable (concordance correlation coefficients 0.859 and 0.833, respectively). AI-aided OCT analysis objectively showed greater plaque stabilization of adding alirocumab to rosuvastatin. Our results highlight the benefits of a fully automated AI-assisted approach for assessing drug efficacy, offering greater objectivity in evaluating serial changes in plaque stability vs. conventional OCT assessment.

Inhibition of the RXRA-PPARα-FABP4 signaling pathway alleviates vascular cellular aging by an SGLT2 inhibitor in an atherosclerotic mice model.

Atherosclerosis is the pathological cause of atherosclerotic cardiovascular disease (ASCVD), which rapidly progresses during the cellular senescence. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) reduce major cardiovascular events in patients with ASCVD and have potential antisenescence effects. Here, we investigate the effects of the SGLT2 inhibitor dapagliflozin on cellular senescence in atherosclerotic mice. Compared with ApoE-/- control mice treated with normal saline, those in the ApoE-/- dapagliflozin group, receiving intragastric dapagliflozin (0.1 mg kg-1 d-1) for 14 weeks, exhibited the reduction in the total aortic plaque area (48.8%±6.6% vs. 74.6%±8.0%, P<0.05), the decrease in the lipid core area ((0.019±0.0037) mm2vs. (0.032±0.0062) mm2, P<0.05) and in the percentage of senescent cells within the plaques (16.4%±3.7% vs. 30.7%±2.0%, P<0.01), while the increase in the thickness of the fibrous cap ((21.6±2.1) µm vs. (14.6±1.5) µm, P<0.01). Transcriptome sequencing of the aortic arch in the mice revealed the involvement of the PPARα and the fatty acid metabolic signaling pathways in dapagliflozin's mechanism of ameliorating cellular aging and plaque progression. In vitro, dapagliflozin inhibited the expression of PPARα and its downstream signal FABP4, by which the accumulation of senescent cells in human aortic smooth muscle cells (HASMCs) was reduced under high-fat conditions. This effect was accompanied by a reduction in the intracellular lipid content and alleviation of oxidative stress. However, these beneficial effects of dapagliflozin could be reversed by the PPARα overexpression. Bioinformatics analysis and molecular docking simulations revealed that dapagliflozin might exert its effects by directly interacting with the RXRA protein, thereby influencing the expression of the PPARα signaling pathway. In conclusion, the cellular senescence of aortic smooth muscle cells is potentially altered by dapagliflozin through the suppression of the RXRA-PPARα-FABP4 signaling pathway, resulting in a deceleration of atherosclerotic progression.

Optical coherence tomography assessment of the impact of colchicine on non-culprit coronary plaque composition after myocardial infarction.

Low-dose colchicine reduces the risk of cardiovascular events after myocardial infarction (MI). The purpose of this study was to assess the effect of colchicine post-MI on coronary plaque morphology in non-culprit segments by optical coherence tomography (OCT). COCOMO-ACS was a double-blind, placebo-controlled trial that randomized 64 patients (median age 61.5 years; 9.4% female) with acute non-ST-segment elevation MI to colchicine 0.5 mg daily or placebo for a median of 17.8 months in addition to guideline-recommended therapy. Participants underwent serial OCT imaging within a matched segment of non-culprit coronary artery which contained at least one lipid-rich plaque causing ≥20% stenosis. The primary outcome was the change in minimum fibrous cap thickness (FCT) in non-culprit segments from baseline to final visit. Of those randomized, 57 (29 placebo, 28 colchicine) had evaluable imaging at baseline and follow-up. Overall, colchicine had no effect on relative (placebo +48.0±35.1% vs. colchicine +62.4±38.1%, P=0.18) or absolute changes in minimum FCT (+29.2±20.9 µm vs. +37.2±21.3 µm, P=0.18), or change in maximum lipid arc (-38.8±32.2° vs. -54.8±46.9°, P=0.18) throughout the imaged non-culprit segment. However, in patients assigned colchicine, cap rupture was less frequent (placebo 27.6% vs. colchicine 3.6%, P=0.03). In post-hoc analysis of 43 participants who had been followed for at least 16 months, minimum FCT increased to a greater extent in the colchicine group (placebo +38.7±25.4% vs. colchicine +64.7±34.1%, P=0.005). In this study, OCT failed to detect an effect of colchicine on the minimum FCT or maximum lipid arc of plaques in non-culprit segments post-MI. The post-hoc observation that minimum FCT increased to a greater extent with colchicine after more prolonged treatment suggests longer-term studies may be required to detect the effect of anti-inflammatory therapies on plaque morphology by OCT. Australian New Zealand Clinical Trials Registry Identifier, ACTRN12618000809235, registered on the 11th of May 2018.

Sex differences in plaque characteristics of fractional flow reserve-negative non-culprit lesions after myocardial infarction

Background and aimsRecurrent events after myocardial infarction (MI) are common and often originate from native non-culprit (NC) lesions that are non-flow limiting. These lesions consequently pose as targets to improve long-term outcome. It is, however, largely unknown whether these lesions differ between sexes. The aim of this study was to assess such potential differences. MethodsFrom the PECTUS-obs study, we assessed sex-related differences in plaque characteristics of fractional flow reserve (FFR)-negative intermediate NC lesions in 420 MI-patients. ResultsAmong the included patients, 80 (19.1 %) were female and 340 (80.9 %) male. Women were older and more frequently had hypertension and diabetes. In total, 494 NC lesions were analyzed. After adjustment for clinical characteristics and accounting for within-patients clustering, lesion length was longer in female patients (20.8 ± 10.0 vs 18.3 ± 8.5 mm, p = 0.048) and minimum lumen area (2.30 ± 1.42 vs 2.78 ± 1.54 mm2, p < 0.001) and minimum lumen diameter (1.39 ± 0.45 vs 1.54 ± 0.44 mm, p < 0.001) were smaller. The minimum fibrous cap thickness was smaller among females (96 ± 53 vs 112 ± 72 μm, p = 0.025), with more lesions harboring a thin cap fibroatheroma (39.3 % vs 24.9 %, p < 0.001). Major adverse cardiovascular events at two years occurred in 6.3 % of female patients and 11.8 % of male patients (p = 0.15). ConclusionsFFR-negative NC lesions after MI harbored more high-risk plaque features in female patients. Although this did not translate into an excess of recurrent events in female patients in this modestly sized cohort, it remains to be investigated whether this difference affects clinical outcome.

Fractal geometry of culprit coronary plaque images within optical coherence tomography in patients with acute coronary syndrome vs stable angina pectoris.

The main cause of acute coronary syndrome (ACS) is plaque rupture and thrombus formation. However, it has not been fairly successful to identify vulnerable plaque to rupture using conventional parameters of intravascular imaging modalities. Fractal analysis is one of the mathematical models to examine geometrical features of picture image using a specific parameter called as fractal dimension (FD) which suggests geometric complexity of the image. This study examined FD of the optical coherence tomography (OCT)-derived images of the culprit plaque in patients with ACS vs stable angina pectoris (SAP) to evaluate the feasibility of FD for identifying vulnerable coronary plaques prone to provoke ACS distinguished from stable plaques only provoking SAP. We examined 65 cases (34 ACS patients, 31 SAP patients) in which the culprit lesion was imaged by OCT before percutaneous coronary intervention in patients with ACS and SAP. The culprit plaque lesion in the ACS group had a significantly larger mean lipid arc (203.8 ± 39.4° vs 152.3 ± 34.5°, p < 0.001) and a larger lipid plaque length (12.6 ± 5.1mm vs 7.7 ± 2.7mm, p < 0.001) and a thinner fibrous cap thickness (75.3 ± 22.3μm vs 134.8 ± 53.2μm, p < 0.001) than those in the SAP group. The prevalence of OCT-derived macrophage infiltration (Mph) in the entire culprit coronary vessel as well as that of the OCT-derived thin-cap fibroatheroma (TCFA) at the culprit lesion were significantly greater in the ACS group than those in the SAP group, respectively (Mph: 61.8% vs 35.5%, p = 0.048; TCFA: 44.1% vs 6.4%, p < 0.001). The FD of culprit plaque in the ACS group was significantly greater than in the SAP group (2.401 ± 0.073 vs 2.341 ± 0.051, p < 0.001). In multivariate regression analysis, the presence of Mph was a significant determinant of FD (regression coefficient estimate 0.049, CI 0.018-0.079, p = 0.002). The FD of OCT-derived image of culprit coronary plaque in the ACS group was significantly greater than that in the SAP group, indicating that the culprit plaque in ACS were structurally more complex. Therefore, fractal analysis of coronary OCT images might be clinically useful for identifying coronary plaques prone to provoke ACS.

Smooth muscle-specific deletion of Ccn2 causes severe aorta malformation and atherosclerosis.

Cellular Communication Network Factor 2 (CCN2) is a matricellular protein implicated in fibrotic diseases, with ongoing clinical trials evaluating anti-CCN2-based therapies. By uncovering CCN2 as abundantly expressed in non-diseased artery tissue, this study aimed to investigate the hypothesis that CCN2 plays a pivotal role in maintaining smooth muscle cell (SMC) phenotype and protection against atherosclerosis. Global- and SMC-specific Ccn2 knockout mouse models were employed to demonstrate that Ccn2 deficiency leads to SMC de-differentiation, medial thickening, and aorta elongation under normolipidemic conditions. Inducing hyperlipidemia in both models resulted in severe aorta malformation and a 17-fold increase in atherosclerosis formation. Lipid-rich lesions developed at sites of the vasculature typically protected from atherosclerosis-development by laminar blood flow, covering 90% of aortas, and extending to other vessels, including coronary arteries. Evaluation at earlier time points revealed medial lipid accumulation as a lesion-initiating event. Fluorescently labelled LDL injection followed by confocal microscopy showed increased LDL retention in the medial layer of Ccn2 knockout aortas, likely attributed to marked proteoglycan enrichment of the medial extracellular matrix. Analyses leveraging data from the Athero-Express study cohort indicated relevance of CCN2 in established human lesions, as CCN2 correlated with SMC marker transcripts across 654 transcriptomically profiled carotid plaques. These findings were substantiated through in situ hybridization showing CCN2 expression predominantly in the fibrous cap. This study identifies CCN2 as a major constituent of the normal artery wall, critical in regulating SMC differentiation and aorta integrity, and possessing a protective role against atherosclerosis development. These findings underscore the need for further investigation into the potential effects of anti-CCN2-based therapies on the vasculature.

Plaque Characteristics Derived from Intravascular Optical Coherence Tomography That Predict Cardiovascular Death.

This study aimed to investigate whether plaque characteristics derived from intravascular optical coherence tomography (IVOCT) could predict a long-term cardiovascular (CV) death. This study was a single-center, retrospective study on 104 patients who had undergone IVOCT-guided percutaneous coronary intervention. Plaque characterization was performed using Optical Coherence TOmography PlaqUe and Stent (OCTOPUS) software developed by our group. A total of 31 plaque features, including lesion length, lumen, calcium, fibrous cap (FC), and vulnerable plaque features (e.g., microchannel), were computed from the baseline IVOCT images. The discriminatory power for predicting CV death was determined using univariate/multivariate logistic regressions. Of 104 patients, CV death was identified in 24 patients (23.1%). Univariate logistic regression revealed that lesion length, calcium angle, calcium thickness, FC angle, FC area, and FC surface area were significantly associated with CV death (p < 0.05). In the multivariate logistic analysis, only the FC surface area (OR 2.38, CI 0.98-5.83, p < 0.05) was identified as a significant determinant for CV death, highlighting the importance of the 3D lesion analysis. The AUC of FC surface area for predicting CV death was 0.851 (95% CI 0.800-0.927, p < 0.05). Patients with CV death had distinct plaque characteristics (i.e., large FC surface area) in IVOCT. Studies such as this one might someday lead to recommendations for pharmaceutical and interventional approaches.

Diagnostic accuracy of carotid plaque magnetic resonance imaging compared to histopathology in symptomatic carotid artery stenosis

IntroductionVulnerable plaques have been shown to predict ipsilateral cerebral ischemic events and identifying them leads to appropriate secondary stroke prevention strategies. We evaluated the diagnostic accuracy of MR carotid plaque imaging in identifying plaque vulnerability when compared with histopathological findings in patients with symptomatic carotid stenosis who underwent carotid endarterectomy (CEA). MethodsA prospective cohort of forty-five consecutive patients with moderate to severe symptomatic carotid stenosis who underwent CEA at a tertiary Indian hospital had 3 T MRI plaque imaging with multi-parametric protocol between November 2021 and December 2022. Images were analyzed by a vascular radiologist blinded to histopathological data. High-risk plaque characteristics such as lipid rich necrotic core (LRNC), intraplaque hemorrhage (IPH), thin fibrous cap and ulceration were assessed and correlated with histopathological findings as per American Heart Association (AHA) classification using Cohen’s kappa statistics to obtain diagnostic accuracies. ResultsOf the 45 patients, 38(84 %) were males. The mean age was 65 ± 7.7 years and mean duration to CEA from the most recent event was 57 days (57 ± 46 days). A significant correlation between MR plaque imaging and histopathology was noted for IPH (sensitivity-91 %, specificity-86 %, κ = 0.774, p < 0.001), LRNC (sensitivity-92.1 %, specificity-85.7 %, κ = 0.697, p < 0.001), and plaque ulceration (sensitivity-84.6 %, specificity-78.1 %, κ = 0.563, p < 0.001). MRI had an overall sensitivity and specificity of 92.3 % and 84.2 % respectively (κ = 0.77, p < 0.001) in discriminating high risk plaques. ConclusionMR plaque imaging shows a very good correlation with histopathology and can identify unstable high-risk plaques with high accuracy. This may have implication in selection of patients for carotid revascularization in symptomatic carotid stenosis.

Potential of diagnostic electron microscopy of calcification, pathological neovascularization and elastolysis in combination with phenotyping of cell populations in large arteries

Aim. To determine the potential of diagnostic electron microscopy of intraplaque processes (severity of lipid damage, fibrous cap thickness and condition, severity of pathological neovascularization, presence, nature and severity of calcification, ratio and distribution of various cell populations).Material and methods. The study objects were plaques removed during endar­terectomy from the human carotid artery and segments of the human internal mammary artery removed during coronary bypass surgery. Whole specimens were subjected to chemical fixation, staining with heavy metal salts, embedding in epoxy resin followed by layer-by-layer grinding, polishing, contrasting, visualization using back-scattered electron scanning electron microscopy and three-dimensional reconstruction with color mapping (modified EM-BSEM).Results. The use of a modified EM-BSEM made it possible to: 1) visualize the fibrous cap thickness and assess the extracellular matrix; 2) analyze the neointimal lipid distribution; 3) perform three-dimensional reconstruction and analyze the microenvironment of calcifications of various sizes; 4) visualize endothelial cells, defects in interendothelial contacts and the basement membrane of neointimal capillaries with their subsequent three-dimensional reconstruction; 5) perform an analysis of age-dependent defects in the basement membrane and internal elastic membrane of the internal mammary artery. The resolution of the obtained images was significantly superior to intravascular imaging methods (intravascular ultrasound and optical coherence tomography), allowing additional assessment of capillary fluidity, the degree of calcification encapsulation and the condition of elastic fibers. Three-dimensional reconstruction of calcifications, neointimal capillaries and elastic fibers made it possible to assess their spatial density and heterogeneity. Simultaneously with the identification and assessment of these histological structures, objective phenotyping of cell populations was performed, which made it possible to isolate macrophages and foam cells, vascular smooth muscle cells, fibroblasts and endothelial cells in atherosclerotic plaques and automatically identify them through color mapping determined by their electronic contrast distribution signatures.Conclusion. The modified EM-BSEM method allows for universal electron microscopic diagnosis of atherosclerotic and elastolytic lesions of large arteries with high information content about vascular remodeling and high accuracy. Electronic contrast distribution signatures unique for each cell population indicate the possibility of their automated phenotyping using specialized neural network algorithms.

Role of imaging techniques in the assessment of vulnerable plaques and the effectiveness of lipid-lowering therapy

The aim was to evaluate the potential of various imaging methods in the diagnosis of vulnerable coronary plaques and their stabilization using various lipid-lowering therapy regimens.The sources were searched in the PubMed database using the following keywords: "vulnerable (unstable) plaque" AND "PCSK9 inhibitors" AND "intravascular ultrasound" OR "optical coherence tomography" OR "computed tomography angiography". As a result, 8 original clinical trials were selected that corresponded to the review purpose. We assessed the results of following studies on plaque imaging and their regression with various lipid-lowering therapy regimens: GLAGVO, ODYSSEY J, PACMAN-AMI, HUYGENS, ALTAIR, ARCHITECT, etc. The results of most studies have established the advantages of a combined regimen of lipid-lowering therapy (statin+PCSK9 inhibitor) in reducing the rate of cardiovascular events in com­parison with statin monotherapy. The reduction in plaque volume ranged from 0,95% to 2,13% in patients receiving a combination of lipid-lowering drugs, while in monotherapy, it increased from 0,05% to 0,92% (GLAGOV, PACMAN-AMI). The changes of minimum fibrous cap thickness varied from 18,0-62,67 µm with combined therapy and 13,2-33,19 µm with monotherapy (PACMAN-AMI, Gao F). Lipid arc regression was 57,5о in combination therapy (statin+PCSK9 inhibitor) and 31,4о in statin monotherapy (HUYGENS). Imaging diagnostic methods makes it possible to identify vulnerable plaques, which helps in consideration of combination lipid-lowering therapy. In addition, plaque visualization makes it possible to evaluate the treatment effectiveness.

Photodynamic Therapy of Atherosclerotic Plaque Monitored by T1 and T2 Relaxation Times of Magnetic Resonance Imaging

Atherosclerosis, marked by plaque accumulation within arteries, results from lipid dysregulation, inflammation, and vascular remodeling. Plaque composition, including lipid-rich cores and fibrous caps, determines stability and vulnerability. Photodynamic therapy (PDT) has emerged as a promising treatment, leveraging photosensitizers to induce localized cytotoxicity upon light activation. PDT targets plaque components selectively, reducing burden and inflammation. Challenges remain in optimizing PDT parameters and translating preclinical success to clinical efficacy. Nonetheless, PDT offers a minimally invasive strategy for atherosclerosis management, promising personalized interventions for cardiovascular health. The objective of the current study was to present the findings from quantitative non-contrast MRI of atherosclerosis post-PDT by assessing relaxation times. The study aimed to utilize and optimize a 1.5T MRI system. Clinical scanners were used for MRI examinations. The research involved analyzing T1 and T2 relaxation times. Following treatment of the samples with Rose Bengal and exposure to pure oxygen, PDT irradiation was administered. The results indicated that the therapy impacted the crus, evidenced by a significant decrease in relaxation times in the MRI data.

Abstract Tu015: Angiopoietin-like 4 Stabilizes Atherosclerotic Plaques by Modulating the Phenotypic Transition of Endothelial Cells and Vascular Smooth Muscle Cells

Atherosclerosis, the leading cause of death, is a vascular disease of chronic inflammation. We recently showed that angiopoietin-like 4 (ANGPTL4) promotes cardiac repair by suppressing pathological inflammation. Given the fundamental contribution of inflammation to atherosclerosis, we assessed the role of ANGPTL4 in the development of atherosclerosis and determined whether ANGPTL4 regulates atherosclerotic plaque stability. We injected ANGPTL4 protein twice a week into atherosclerotic Apoe-/- mice and analyzed the atherosclerotic lesion size, endothelial dysfunction, inflammation, and plaque stability. In atherosclerotic mice, ANGPTL4 reduced the atherosclerotic plaque size, endothelial dysfunction, and vascular inflammation. Furthermore, ANGPTL4 was associated with maintenance of vascular integrity and attenuated endothelial-to-mesenchymal transition (EndMT) in both HUVEC and atherosclerotic plaque of Apoe-/- mice. In the atherosclerotic lesions and fibrous caps, the number of α-SMA(+), SM22α(+), and SM-MHC(+) cells was higher, while the number of CD68(+) and Mac2(+) cells was lower in the ANGPTL4 group. Most importantly, the fibrous cap was significantly thicker in the ANGPTL4 group than in the PBS group. Smooth muscle cells (SMCs) isolated from atherosclerotic aortas showed significantly increased expression of CD68 and Krüppel-like factor 4 (KLF4), a modulator of the vascular SMC phenotype, along with downregulation of α-SMA, and these changes were attenuated by ANGPTL4 treatment. Furthermore, ANGPTL4 reduced TNFa-induced NADPH oxidase 1 (NOX1), a major source of reactive oxygen species, resulting in attenuation of KLF4-mediated SMC phenotypic changes. Our results reveal that ANGPTL4 treatment inhibits atherogenesis and suggest that targeting vascular stability and inflammation may serve as a novel therapeutic strategy to prevent and treat atherosclerosis. Even more importantly, ANGPTL4 treatment inhibited the phenotypic changes of SMCs into macrophage-like cells by downregulating NOX1 activation of KLF4, leading to the formation of more stable plaques.

Abstract Tu012: Innate Immune Pathway cGAS-STING in Macrophage Function in Atherosclerosis

Macrophages are key cells in atherosclerotic cardiovascular disease. Macrophages within a single plaque are heterogenous: some are lipid-laden “foam cells” with varying ability to recycle lipoproteins or clear dead cells while others secrete traditional “pro-inflammatory” signals. Determining what signals bias macrophages to one phenotype versus another could identify a therapeutic target. Our lab showed that after acute myocardial infarction, macrophages are skewed to a reparative phenotype by loss of cGAS-STING signaling. cGAS-STING are a pattern recognition receptor-adaptor pair that are activated by double stranded DNA in a sequence-independent manner. Global deletion of Sting and Cgas have been shown to protect against atherosclerosis in mice. We hypothesize that hematopoietic-specific loss of Cgas will reduce plaque burden by biasing macrophages to a less inflammatory phenotype and upregulating pro-resolving functions. To test this, B6.129S7- Ldlr tm1Her /J ( Ldlr -/-) mice (female, age 8-12 weeks, 9 per group) underwent total body irradiation followed by bone marrow transplant from C57BL6/N- Cgas -/- ( Cgas -/-) or wildtype donor mice (female, age 6-8 weeks). After bone marrow reconstitution, recipient mice were started on Western diet. Mice will continue Western diet for 12 weeks (through April 24, 2024). Then, aortas, peripheral blood, spleen, and bone marrow will be collected for further analysis including plaque burden, fibrous cap thickness, and macrophage phenotype. We will also perform in vitro studies using primary macrophages to determine how Cgas -/- affects macrophage effector functions critical for atherosclerosis. To date, mice that received Cgas -/- or wildtype donor bone marrow had similar baseline cell count, triglyceride and total cholesterol levels. Bone marrow derived macrophages (BMDM) from Cgas -/- mice have increased expression of fibronectin. Thus, at baseline Cgas -/- BMDM express high levels of a marker associated with pro-reparative macrophages. More studies are needed to characterize this phenotype and determine the consequence for in vivo atherosclerosis.

Efficacy, safety and mechanism of Simiaoyongan decoction in the treatment of carotid atherosclerotic plaque: a randomized, double-blind, placebo-controlled clinical trial protocol

IntroductionChronic inflammation is the major pathological feature of Atherosclerosis(As). Inflammation may accelerate plaque to develop, which is a key factor resulting in the thinning of the fibrous cap and the vulnerable rupture of plaque. Presently, clinical treatments are still lacking. It is necessary to find a safe and effective treatment for As inflammation. Simiaoyongan Decoction (SMYA) has potential anti-inflammatory and plaque protection effects. This protocol aims to evaluate the efficacy, safety, and mechanism of SMYA for patients with carotid atherosclerotic plaque.Methods/designThe assessment of SMYA clinical trial is designed as a randomized, double-blind, placebo-controlled study. The sample size is 86 cases in total, with 43 participants in the intervention group and the control group respectively. The intervention group takes SMYA, while the control group takes SMYA placebo. The medication lasts for 14 days every 10 weeks, with a total of 50 weeks. We will use carotid artery high resolution magnetic resonance imaging (HR-MRI) to measure plaque. The plaque minimum fiber cap thickness (PMFCT) is adopted as the primary outcome. The secondary outcomes include plaque fiber cap volume, volume percentage of fiber cap, lipid-rich necrotic core (LRNC) volume, volume percentage of LRNC, internal bleeding volume of plaque, internal bleeding volume percentage of plaque, plaque calcification volume, volume percentage of plaque calcification, lumen stenosis rate, average and a maximum of vessel wall thickness, vessel wall volume, total vessel wall load, carotid atherosclerosis score, hs-CRP, IL-1β and IL-6, the level of lipid profiles and blood glucose, blood pressure, and body weight.DiscussionWe anticipate that patients with As plaque will be improved from SMYA by inhibiting inflammation to enhance plaque stability. This study analyzes plaque by using HR-MRI to evaluate the clinical efficacy and safety of SMYA. Moreover, we conduct transcriptome analysis, proteomic analysis, and metagenomic analysis of blood and stool of participants to study the mechanism of SMYA against As plaque. This is the first prospective TCM trial to observe and treat As plaque by inhibiting inflammatory reaction directly. If successful, the finding will be valuable in the treatment of As plaque and drug development, especially in the “statin era”.Trial registration numberThis trial is registered on Chinese Clinical Trials.gov with number ChiCTR2000039062 on October 15, 2020 (http://www.chictr.org.cn).

Cyclic Nitroxide 4-Methoxy-Tempo May Decrease Serum Amyloid A-Mediated Renal Fibrosis and Reorganise Collagen Networks in Aortic Plaque.

Acute-phase serum amyloid A (SAA) can disrupt vascular homeostasis and is elevated in subjects with diabetes, cardiovascular disease, and rheumatoid arthritis. Cyclic nitroxides (e.g., Tempo) are a class of piperidines that inhibit oxidative stress and inflammation. This study examined whether 4-methoxy-Tempo (4-MetT) inhibits SAA-mediated vascular and renal dysfunction. Acetylcholine-mediated vascular relaxation and aortic guanosine-3',5'-cyclic monophosphate (cGMP) levels both diminished in the presence of SAA. 4-MetT dose-dependently restored vascular function with corresponding increases in cGMP. Next, male ApoE-deficient mice were administered a vehicle (control, 100 µL PBS) or recombinant SAA (100 µL, 120 µg/mL) ± 4-MetT (at 15 mg/kg body weight via i.p. injection) with the nitroxide administered before (prophylaxis) or after (therapeutic) SAA. Kidney and hearts were harvested at 4 or 16 weeks post SAA administration. Renal inflammation increased 4 weeks after SAA treatment, as judged by the upregulation of IFN-γ and concomitant increases in iNOS, p38MAPK, and matrix metalloproteinase (MMP) activities and increased renal fibrosis (Picrosirius red staining) in the same kidneys. Aortic root lesions assessed at 16 weeks revealed that SAA enhanced lesion size (vs. control; p < 0.05), with plaque presenting with a diffuse fibrous cap (compared to the corresponding aortic root from control and 4-MetT groups). The extent of renal dysfunction and aortic lesion size was largely unchanged in 4-MetT-supplemented mice, although renal fibrosis diminished at 16 weeks, and aortic lesions presented with redistributed collagen networks. These outcomes indicate that SAA stimulates renal dysfunction through promoting the IFN-γ-iNOS-p38MAPK axis, manifesting as renal damage and enhanced atherosclerotic lesions, while supplementation with 4-MetT only affected some of these pathological changes.

Peritoneal Dialysis Aggravates and Accelerates Atherosclerosis in Uremic ApoE-/- Mice.

Atherosclerosis is highly prevalent in people with chronic kidney disease (CKD), including those receiving peritoneal dialysis (PD). Although it is lifesaving, PD induces profound systemic inflammation, which may aggravate atherosclerosis. Therefore, the hypothesis is that this PD-induced inflammation aggravates atherosclerosis via immune cell activation. ApoE-/- mice were subjected to a 5/6 nephrectomy to induce CKD. Three weeks later, mice were fed a high-cholesterol diet. Half of the nephrectomized mice then received daily peritoneal infusions of 3.86% Physioneal for 67 further days (CKD+PD) until the end of the experiment, and were compared with mice without CKD. Sham operated and PD-only mice were additional controls. CKD+PD mice displayed more severe atherosclerotic disease than control mice. Plaque area increased, and plaques were more advanced with a vulnerable phenotype typified by decreased collagen content and decreased fibrous cap thickness. Increased CD3+ T-cell numbers were present in plaques and perivascular adipose tissue of CKD and CKD+PD mice. Plaques of CKD+PD mice contained more iNOS+ immune cells. Spleens of CKD+PD mice showed more CD4+ central memory, terminally differentiated type 1 T-helper (Th1), Th17, and CX3C motif chemokine receptor 1+ (CX3CR1) CD4+ T-cells with less regulatory and effector T-cells. PD-fluid exposure in uremic mice potentiates systemic and vascular T-cell-driven inflammation and aggravates atherosclerosis. PD polarized CD4+ T-cells toward an inflammatory Th1/Th17 phenotype, and increased CX3CR1+ CD4+ T-cells, which are associated with vascular homing in CKD-associated atherosclerosis. Targeting CD4+ T-cell activation and CX3CR1+ polarization has the potential to attenuate atherosclerosis in PD patients.

Impact of distribution of carotid intraplaque neovessels on plaque vulnerability

Background and PurposeIntraplaque neovessels (INVs) are considered important contributors to carotid plaque vulnerability. The purpose of this study was to examine whether differences in INV distribution affect plaque vulnerability. MethodsThe study cohort comprised 110 patients with significant stenosis of the carotid artery who had undergone carotid endarterectomy. The distribution of INVs within carotid plaques was assessed by immunohistochemical studies using anti-CD-34 antibody as a marker for endothelial cells. First, we divided the patients into M group and S group depending on the numbers of INVs in middle and shoulder region. Next, we categorized carotid plaques into four categories according to the distributions of INVs: Shoulder, Middle, Mixed, and Scarce. We then compared total area of intraplaque hemorrhage, cholesterol, and calcification, width of thinnest fibrous cap, and number of INVs between the four categories of plaque. ResultsThe area of intraplaque hemorrhage was significantly larger in the M group than in the S group (P = 0.011). Meanwhile, symptomatic carotid stenosis was significantly more frequently associated with the Middle and Mixed than the Shoulder and Scarce categories (P < 0.01). The area of intraplaque hemorrhage was significantly different between the four groups (P = 0.022). Rupture of the fibrous cap was more frequently detected in the Middle and Mixed than the other categories (P = 0.002). ConclusionsINVs in the middle region of carotid plaques are strongly associated with symptomatic carotid stenosis, intraplaque hemorrhage, and rupture of the fibrous cap. Our findings indicate that the distribution of INVs may affect plaque vulnerability.

Diagnostics Accuracy of Magnetic Resonance Imaging in Detection of Atherosclerotic Plaque Characteristics in Carotid Arteries Compared to Histology: A Systematic Review.

Carotid plaque composition represents one of the main risk factors of future ischemic stroke. MRI provides excellent soft tissue contrast that can distinguish plaque characteristics. Our objective was to analyze the diagnostic accuracy of MRI imaging in the detection of carotid plaque characteristics compared to histology in patients with symptomatic and asymptomatic carotid atherosclerosis through a systematic review. After prospective registration in PROSPERO (ID CRD42022329690), Medline Ovid, Embase.com, Cochrane Library, and Web of Science Core were searched without any search limitation up to May 27, 2022 to identify eligible articles. Of the 8168 studies, 53 (37 × 1.5 T MRI, 17 × 3 T MRI) evaluated MRI accuracy in the detection of 13 specific carotid plaque characteristics in 169 comparisons. MRI demonstrated high diagnostic accuracy for detection of calcification (3 T MRI: mean sensitivity 92%/mean specificity 90%; 1.5 T MRI: mean sensitivity 81%/mean specificity 91%), fibrous cap (1.5 T: 89%/87%), unstable plaque (1.5 T: 89%/87%), intraplaque hemorrhage (1.5 T: 86%/88%), and lipid-rich necrotic core (1.5 T: 89%/79%). MRI also proved to have a high level of tissue discrimination for the carotid plaque characteristics investigated, allowing potentially for a better risk assessment and follow-up of patients who may benefit from more aggressive treatments. These results emphasize the role of MRI as the first-line imaging modality for comprehensive assessment of carotid plaque morphology, particularly for unstable plaque. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Melatonin Ameliorates Atherosclerotic Plaque Vulnerability by Regulating PPARδ-Associated Smooth Muscle Cell Phenotypic Switching.

Vulnerable atherosclerotic plaque rupture, the leading cause of fatal atherothrombotic events, is associated with an increased risk of mortality worldwide. Peroxisome proliferator-activated receptor delta (PPARδ) has been shown to modulate vascular smooth muscle cell (SMC) phenotypic switching, and, hence, atherosclerotic plaque stability. Melatonin reportedly plays a beneficial role in cardiovascular diseases; however, the mechanisms underlying improvements in atherosclerotic plaque vulnerability remain unknown. In this study, we assessed the role of melatonin in regulating SMC phenotypic switching and its consequential contribution to the amelioration of atherosclerotic plaque vulnerability and explored the mechanisms underlying this process. We analyzed features of atherosclerotic plaque vulnerability and markers of SMC phenotypic transition in high-cholesterol diet (HCD)-fed apolipoprotein E knockout (ApoE-/-) mice and human aortic SMCs (HASMCs). Melatonin reduced atherosclerotic plaque size and necrotic core area while enhancing collagen content, fibrous cap thickness, and smooth muscle alpha-actin positive cell coverage on the plaque cap, which are all known phenotypic characteristics of vulnerable plaques. In atherosclerotic lesions, melatonin significantly decreased the synthetic SMC phenotype and KLF4 expression and increased the expression of PPARδ, but not PPARα and PPARγ, in HCD-fed ApoE-/- mice. These results were subsequently confirmed in the melatonin-treated HASMCs. Further analysis using PPARδ silencing and immunoprecipitation assays revealed that PPARδ plays a role in the melatonin-induced SMC phenotype switching from synthetic to contractile. Collectively, we provided the first evidence that melatonin mediates its protective effect against plaque destabilization by enhancing PPARδ-mediated SMC phenotypic switching, thereby indicating the potential of melatonin in treating atherosclerosis.

Early and short-term use of proprotein convertase anti-subtilisin-kexin type 9 inhibitors on coronary plaque stability in acute coronary syndrome.

Proprotein convertase anti-subtilisin-kexin type 9 inhibitors (PCSK9Is) improve plaque volume and composition and reduce major adverse coronary events in chronic coronary artery disease. We evaluated the effects of the short-term use of PCSK9Is on coronary plaque stability in patients with acute coronary syndrome (ACS) using optical coherence tomography (OCT). This is a multicentre, open-label randomized controlled trial. The enrolled 80 subjects met the inclusion criteria. Of these, 52 patients (age 60 ± 11 years, 38 men, 14 women) with ST-elevated ACS had undergone successful primary percutaneous coronary intervention with LDL-cholesterol (LDL-C) levels > 70 mg/dL while receiving high-intensity statins. Participants were randomly assigned to the PCSK9I group (evolocumab 420 mg for 3 months, n = 29) or the standard of care (SoC) group (n = 23). Optical coherence tomography was performed at baseline (BL) and 3 and 9 months after randomization to assess lipid-rich plaques in non-culprit lesions. The change in the minimum fibrous cap thickness (MFCT) from BL to 9 months was the primary endpoint. The percentage change in LDL-C levels from BL to 3 months was significantly greater in the PCSK9I group (-67.8 ± 21.5% in the PCSK9I group vs. -16.3 ± 21.8% in the SoC group; P < 0.0001), and the difference between the two groups disappeared from BL to 9 months (-20.0 ± 37.8% in the PCSK9I group vs. -6.7 ± 34.2% in the SoC group; P = 0.20). The changes in MFCT from BL to 9 months were significantly greater in the PCSK9I group, even after PCSK9I discontinuation {100 μm [interquartile range (IQR): 45-180 μm] vs. 50 μm [IQR: 0-110 μm]; P = 0.032}. Combination treatment with PCSK9Is and statins resulted in more marked plaque stabilization after ACS than SoC alone, and this effect persisted for 6 months after PCSK9I discontinuation. Adage-Joto study, UMIN ID No. 26516.