Abstract P408: Mesenchymal Stem Cell-derived Angptl4 Improves Endothelial Permeability And Resolution Of Inflammation In Atherosclerosis

Objective: Given the fundamental contribution of inflammation to atherosclerosis, we studied the effect of ANGPTL4 in regulating vascular lesions during atherosclerosis. Methods and Results: We analyzed plasma levels of ANGPTL4 and found that acute myocardial infarction (AMI) patients with higher levels of ANGPTL4 had fewer vascular events than did patients with lower ANGPTL4 levels ( p <0.05). Moreover, in AMI patients with heart failure (HF) at admission, the recurrence of HF was lower in patients with a higher level of ANGPTL4. We then investigated the therapeutic application of ANGPTL4 in an atherosclerosis model. Apoe-/- mice fed a high-fat diet were injected with PBS or ANGPTL4 protein (2 μg per mouse, i.p. ) three times per week for 7 weeks. En face staining and mRNA analysis showed that plaque size, necrotic core area, lipid accumulation, and inflammatory molecules were greatly reduced in the ANGPTL4 group. Aortic permeability, measured by leakage of Evans blue dye, was significantly decreased in the ANGPTL4 group. The induction of pro-inflammatory mediators was significantly inhibited in endothelial cells, vascular smooth muscle cells, and macrophages by ANGPTL4 treatment. Endothelial Krüppel-like factor 2 (KLF2) and VE-cadherin were restored to contribute to maintenance of vascular integrity by ANGPTL4 treatment. Elevated levels of circulating leptin, interleukin-6, and interleukin-1β were profoundly reduced. Most importantly, the fibrous cap was significant thicker in the ANGPTL4 group than in the PBS group. Conclusions: ANGPTL4 treatment attenuated atherogenesis, which suggests that targeting vascular stability and inflammation may serve as a novel therapeutic strategy to prevent and treat atherosclerosis. More importantly, ANGPTL4 treatment inhibits necrotic core formation in lesions, leading to the formation of more stable plaques as evidenced by increased fibrous cap thickness.

Research on the correlation between activating transcription factor 3 expression in the human coronary artery and atherosclerotic plaque stability

Background Activating transcription factor 3 (ATF3) is an early response gene that is activated in response to atherosclerotic stimulation and may be an important factor in inhibiting the progression of atherosclerosis. In this study, we directly measured the expression of ATF3 and inflammatory factors in human coronary atherosclerotic plaques to examine the relationship between ATF3 expression, inflammation and structural stability in human coronary atherosclerotic plaques. Methods A total of 68 coronary artery specimens were collected from the autopsy group, including 36 cases of sudden death from coronary heart disease (SCD group) and 32 cases of acute death caused by mechanical injury with coronary atherosclerosis (CHD group). Twenty-two patients who had no coronary heart disease were collected as the control group (Con group). The histological structure of the coronary artery was observed under a light microscope after routine HE staining, and the intimal and lesion thicknesses, thickness of the fibrous cap, thickness of necrosis core, degree of lumen stenosis were assessed by image analysis software. Western blotting and immunohistochemistry were used to measure the expression and distribution of ATF3, inflammatory factors (CD45, IL-1β, TNF-α) and matrix metalloproteinase-9 (MMP-9) and vascular cell adhesion molecule 1 (VCAM1) in the coronary artery. The Pearson correlation coefficient was used to analyse the correlation between ATF3 protein expression and inflammatory factors and between ATF3 protein expression and structure-related indexes in the lesion group. Results Compared with those in the control group, the intima and necrotic core in the coronary artery were thickened, the fibrous cap became thin and the degree of vascular stenosis was increased in the lesion group, while the intima and necrotic core became thicker and the fibrous cap became thinner in the SCD group than in the CHD group (P < 0.05). There was no or low expression of ATF3, inflammatory factors, VCAM1 and MMP-9 in the control group, and the expression of inflammatory factors, VCAM1 and MMP-9 in the SCD group was higher than that in CHD group, while the expression of ATF3 in the SCD group was significantly lower than that in CHD group (P < 0.05). In the lesion group, the expression of ATF3 was negatively correlated with intimal and necrotic focus thickness, positively correlated with fibrous cap thickness (P < 0.01), and negatively correlated with inflammatory factors, VCAM1 and MMP-9 (P < 0.01). Conclusions The expression of ATF3 may be related to the progression and stability of atherosclerotic plaques, and may affect the structural stability of atherosclerotic plaques by regulating the inflammatory response, thus participating in the regulation of atherosclerotic progression.

Reactive oxygen species scavenging and inflammation mitigation enabled by biomimetic prussian blue analogues boycott atherosclerosis

Background As one typical cardiovascular disease, atherosclerosis severely endanger people’ life and cause burden to people health and mentality. It has been extensively accepted that oxidative stress and inflammation closely correlate with the evolution of atherosclerotic plaques, and they directly participate in all stages of atherosclerosis. Regarding this, anti-oxidation or anti-inflammation drugs were developed to enable anti-oxidative therapy and anti-inflammation therapy against atherosclerosis. However, current drugs failed to meet clinical demands. Methods Nanomedicine and nanotechnology hold great potential in addressing the issue. In this report, we engineered a simvastatin (Sim)-loaded theranostic agent based on porous manganese-substituted prussian blue (PMPB) analogues. The biomimetic PMPB carrier could scavenge ROS and mitigate inflammation in vitro and in vivo. Especially after combining with Sim, the composite Sim@PMPB NC was expected to regulate the processes of atherosclerosis. As well, Mn2+ release from PMPB was expected to enhance MRI. Results The composite Sim@PMPB NC performed the best in regulating the hallmarks of atherosclerosis with above twofold decreases, typically such as oxidative stress, macrophage infiltration, plaque density, LDL internalization, fibrous cap thickness and foam cell birth, etc. Moreover, H2O2-induced Mn2+ release from PMPB NC in atherosclerotic inflammation could enhance MRI for visualizing plaques. Moreover, Sim@PMPB exhibited high biocompatibility according to references and experimental results. Conclusions The biomimetic Sim@PMPB theranostic agent successfully stabilized atherosclerotic plaques and alleviated atherosclerosis, and also localized and magnified atherosclerosis, which enabled the monitoring of H2O2-associated atherosclerosis evolution after treatment. As well, Sim@PMPB was biocompatible, thus holding great potential in clinical translation for treating atherosclerosis. Graphic abstract

Optical coherence tomography detection of vulnerable plaques at high risk of developing acute coronary syndrome

Aims The ability of optical coherence tomography (OCT) to detect plaques at high risk of developing acute coronary syndrome (ACS) remains unclear. The aim of this study was to evaluate the association between non-culprit plaques characterized as both lipid-rich plaque (LRP) and thin-cap fibroatheroma (TCFA) by OCT and the risk of subsequent ACS events at the lesion level. Methods and results In 1378 patients who underwent OCT, 3533 non-culprit plaques were analysed for the presence of LRP (maximum lipid arc &gt; 180°) and TCFA (minimum fibrous cap thickness &lt; 65 μm). The median follow-up period was 6 years [interquartile range (IQR): 5–9 years]. Seventy-two ACS arose from non-culprit plaques imaged by baseline OCT. ACS was more often associated with lipidic plaques that were characterized as both LRP and TCFA vs. lipidic plaques that did not have these characteristics [33% vs. 2%, hazard ratio 19.14 (95% confidence interval: 11.74–31.20), P &lt; 0.001]. The sensitivity and specificity of the presence of both LRP and TCFA for predicting ACS was 38% and 97%, respectively. A larger maximum lipid arc [1.01° (IQR: 1.01–1.01°)], thinner minimum fibrous cap thickness [0.99 μm (IQR: 0.98–0.99 μm)], and smaller minimum lumen area [0.78 mm2 (IQR: 0.67–0.90 mm2), P &lt; 0.001] were independently associated with ACS. Conclusion Non-culprit plaques characterized by OCT as both LRP and TCFA were associated with an increased risk of subsequent ACS at the lesion level. Therefore, OCT might be able to detect vulnerable plaques.

The impact of vildagliptin on the daily glucose profile and coronary plaque stability in impaired glucose tolerance patients with coronary artery disease: VOGUE—A multicenter randomized controlled trial

Background The impact of reduction in glycemic excursion on coronary plaques remains unknown. This study aimed to elucidate whether a dipeptidyl peptidase 4 inhibitor could reduce the glycemic excursion and stabilize the coronary plaques compared with conventional management in coronary artery disease (CAD) patients with impaired glucose tolerance (IGT). Methods This was a multicenter, randomized controlled trial including CAD patients with IGT under lipid-lowering therapy receiving either vildagliptin (50 mg once a day) or no medication (control group) regarding glycemic treatment. The primary endpoint was changes in the minimum fibrous cap thickness and lipid arc in non-significant native coronary plaques detected by optical coherence tomography at 6 months after intervention. Glycemic variability expressed as the mean amplitude of glycemic excursion (MAGE) measured with a continuous glucose monitoring system was evaluated before and 6 months after intervention. Results A total of 20 participants with 47 lesions were allocated to either the vildagliptin group (10 participants, 22 lesions) or the control group (10 participants, 25 lesions). The adjusted difference of mean changes between the groups was − 18.8 mg/dl (95% confidence interval, − 30.8 to − 6.8) (p = 0.0064) for the MAGE (vildagliptin, − 20.1 ± 18.0 mg/dl vs. control, 2.6 ± 12.7 mg/dl), − 22.8° (− 40.6° to − 5.1°) (p = 0.0012) for the mean lipid arc (vildagliptin, − 9.0° ± 25.5° vs. control, 15.8° ± 16.8°), and 42.7 μm (15.3 to 70.1 μm) (p = 0.0022) for the minimum fibrous cap thickness (vildagliptin, 35.7 ± 50.8 μm vs. control, − 15.1 ± 25.2 μm). Conclusions Vildagliptin could reduce the MAGE at 6 months and may be associated with the decreased lipid arc and increased minimum FCT of the coronary plaques in CAD patients with IGT as compared with the control group. These findings may represent its potential stabilization effect on coronary plaques, which are characteristic in this patient subset. Trial registration Registered in the UMIN clinical trial registry (UMIN000008620), Name of the registry: VOGUE trial, Date of registration: Aug 6, 2012, URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000010058

ODC (Ornithine Decarboxylase)-Dependent Putrescine Synthesis Maintains MerTK (MER Tyrosine-Protein Kinase) Expression to Drive Resolution

Objective: ODC (ornithine decarboxylase)-dependent putrescine synthesis promotes the successive clearance of apoptotic cells (ACs) by macrophages, contributing to inflammation resolution. However, it remains unknown whether ODC is required for other arms of the resolution program. Approach and Results: RNA sequencing of ODC-deficient macrophages exposed to ACs showed increases in mRNAs associated with heightened inflammation and decreases in mRNAs related to resolution and repair compared with WT (wild type) macrophages. In zymosan peritonitis, myeloid ODC deletion led to delayed clearance of neutrophils and a decrease in the proresolving cytokine, IL (interleukin)-10. Nanoparticle-mediated silencing of macrophage ODC in a model of atherosclerosis regression lowered IL-10 expression, decreased efferocytosis, enhanced necrotic core area, and reduced fibrous cap thickness. Mechanistically, ODC deletion lowered basal expression of MerTK (MER tyrosine-protein kinase)—an AC receptor—via a histone methylation–dependent transcriptional mechanism. Owing to lower basal MerTK, subsequent exposure to ACs resulted in lower MerTK-Erk (extracellular signal-regulated kinase) 1/2–dependent IL-10 production. Putrescine treatment of ODC-deficient macrophages restored the expression of both MerTK and AC-induced IL-10. Conclusions: These findings demonstrate that ODC-dependent putrescine synthesis in macrophages maintains a basal level of MerTK expression needed to optimally resolve inflammation upon subsequent AC exposure.

Optical Coherence Tomography Predictors for a Favorable Vascular Response to Statin Therapy

Background Specific plaque phenotypes that predict a favorable response to statin therapy have not been systematically studied. This study aimed to identify optical coherence tomography predictors for a favorable vascular response to statin therapy. Methods and Results Patients who had serial optical coherence tomography imaging at baseline and at 6 months were included. Thin‐cap area (defined as an area with fibrous cap thickness <200 μm) was measured using a 3‐dimensional computer‐aided algorithm, and changes in the thin‐cap area at 6 months were calculated. A favorable vascular response was defined as the highest tertile in the degree of reduction of the thin‐cap area. Macrophage index was defined as the product of the average macrophage arc and length of the lesion with macrophage infiltration. Layered plaque was defined as a plaque with 1 or more layers of different optical density. In 84 patients, 140 nonculprit lipid plaques were identified. In multivariable analysis, baseline thin‐cap area (odds ratio [OR] 1.442; 95% CI, 1.024–2.031, P =0.036), macrophage index (OR, 1.031; 95% CI, 1.002–1.061, P =0.036), and layered plaque (OR, 2.767; 95% CI, 1.024–7.479, P =0.045) were identified as the significant predictors for a favorable vascular response. Favorable vascular response was associated with a decrease in the macrophage index. Conclusions Three optical coherence tomography predictors for a favorable vascular response to statin therapy have been identified: large thin‐cap area, high macrophage index, and layered plaque. Favorable vascular response to statin was correlated with signs of decreased inflammation. Registration URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01110538.

Specific NLRP3 Inhibition Protects Against Diabetes-Associated Atherosclerosis

Low-grade persistent inflammation is a feature of diabetes-driven vascular complications, in particular activation of the NLRP3-inflammasome to trigger the maturation and release of the inflammatory cytokine interleukin-1β (IL-1β). We investigated whether inhibiting the NLRP3-inflammasome, through the use of the specific small-molecule NLRP3 inhibitor, MCC950, could reduce inflammation, improve vascular function and protect against diabetes-associated atherosclerosis in the streptozotocin (STZ)-induced diabetic Apolipoprotein knockout (ApoE^-/-) mouse. Diabetes led to a ~4-fold increase in atherosclerotic lesions throughout the aorta, which were significantly attenuated with MCC950 (<i>P</i><0.001). This reduction in lesions was associated with decreased monocyte-macrophage content, reduced necrotic core, attenuated inflammatory gene expression (Il-1β, TNFα, ICAM-1, MCP-1, <i>P</i><0.05) and reduced oxidative stress, whilst maintaining fibrous cap thickness. Additionally, vascular function was improved in diabetic vessels of mice treated with MCC950 (<i>P</i><0.05). In a range of cell lines (murine bone marrow-derived macrophages (BMDMs), human monocytic THP-1 cells, PMA-differentiated human macrophages and diabetic human aortic smooth muscle cells (AoSMCs)), MCC950 significantly reduced IL-1β and/or caspase-1 secretion and attenuated leukocyte-SMC interactions under high glucose or LPS conditions. In summary, MCC950 reduces plaque development, promotes plaque stability and improves vascular function, suggesting that targeting NLRP3-mediated inflammation is a novel therapeutic strategy to improve diabetes-associated vascular disease.

Specific NLRP3 Inhibition Protects Against Diabetes-Associated Atherosclerosis

Low-grade persistent inflammation is a feature of diabetes-driven vascular complications, in particular activation of the NLRP3-inflammasome to trigger the maturation and release of the inflammatory cytokine interleukin-1β (IL-1β). We investigated whether inhibiting the NLRP3-inflammasome, through the use of the specific small-molecule NLRP3 inhibitor, MCC950, could reduce inflammation, improve vascular function and protect against diabetes-associated atherosclerosis in the streptozotocin (STZ)-induced diabetic Apolipoprotein knockout (ApoE^-/-) mouse. Diabetes led to a ~4-fold increase in atherosclerotic lesions throughout the aorta, which were significantly attenuated with MCC950 (<i>P</i><0.001). This reduction in lesions was associated with decreased monocyte-macrophage content, reduced necrotic core, attenuated inflammatory gene expression (Il-1β, TNFα, ICAM-1, MCP-1, <i>P</i><0.05) and reduced oxidative stress, whilst maintaining fibrous cap thickness. Additionally, vascular function was improved in diabetic vessels of mice treated with MCC950 (<i>P</i><0.05). In a range of cell lines (murine bone marrow-derived macrophages (BMDMs), human monocytic THP-1 cells, PMA-differentiated human macrophages and diabetic human aortic smooth muscle cells (AoSMCs)), MCC950 significantly reduced IL-1β and/or caspase-1 secretion and attenuated leukocyte-SMC interactions under high glucose or LPS conditions. In summary, MCC950 reduces plaque development, promotes plaque stability and improves vascular function, suggesting that targeting NLRP3-mediated inflammation is a novel therapeutic strategy to improve diabetes-associated vascular disease.