Cytokine Profile and Concentrations of Metabolic Hormones in the Blood of Overweight Men with Coronary Arteriosclerosis.

Plasma concentrations of cytokines and metabolic hormones and their association with vulnerable atherosclerotic plaques were studied in 36 overweight men (age 40-77 years; BMI 25.0-29.9 kg/m2) with coronary atherosclerosis who underwent coronary endarterectomy. According to histological analysis, the patients were divided into two groups: with stable (17 (47.2%) men) and vulnerable (19 (52.8%) men) plaques in the coronary arteries. The plasma levels of cytokines and metabolic hormones were measured by multiplex analysis: C-peptide, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1, glucagon, IL-6, insulin, leptin, monocyte chemoattractant protein-1, and TNFα. In overweight patients with vulnerable plaques, the level of glucagon was lower by 4.17 times, GIP - by 2.47 times, and insulin - by 2.1 times. At the same time, the risk of occurrence of a vulnerable plaque increases by 5.4% with a decrease in GIP concentration by 1 pg/ml irrespectively of age, as well as by 3.1% with an increase in insulin concentration by 10 pg/ml, without achieving statistical significance when included in the age model. Overweight men with coronary atherosclerosis and vulnerable plaques have lower levels of insulin, glucagon, and GIP. The levels of GIP and insulin are inversely associated with the risk of having vulnerable atherosclerotic plaque.

Biliverdin Reductase B Is a Plasma Biomarker for Intraplaque Hemorrhage and a Predictor of Ischemic Stroke in Patients with Symptomatic Carotid Atherosclerosis.

BACKGROUND: Intraplaque hemorrhage (IPH) is a hallmark of atherosclerotic plaque instability. Biliverdin reductase B (BLVRB) is enriched in plasma and plaques from patients with symptomatic carotid atherosclerosis and functionally associated with IPH. OBJECTIVE: We explored the biomarker potential of plasma BLVRB through (1) its correlation with IPH in carotid plaques assessed by magnetic resonance imaging (MRI), and with recurrent ischemic stroke, and (2) its use for monitoring pharmacotherapy targeting IPH in a preclinical setting. METHODS: Plasma BLVRB levels were measured in patients with symptomatic carotid atherosclerosis from the PARISK study (n = 177, 5 year follow-up) with and without IPH as indicated by MRI. Plasma BLVRB levels were also measured in a mouse vein graft model of IPH at baseline and following antiangiogenic therapy targeting vascular endothelial growth factor receptor 2 (VEGFR-2). RESULTS: Plasma BLVRB levels were significantly higher in patients with IPH (737.32 ± 693.21 vs. 520.94 ± 499.43 mean fluorescent intensity (MFI), p = 0.033), but had no association with baseline clinical and biological parameters. Plasma BLVRB levels were also significantly higher in patients who developed recurrent ischemic stroke (1099.34 ± 928.49 vs. 582.07 ± 545.34 MFI, HR = 1.600, CI [1.092-2.344]; p = 0.016). Plasma BLVRB levels were significantly reduced following prevention of IPH by anti-VEGFR-2 therapy in mouse vein grafts (1189 ± 258.73 vs. 1752 ± 366.84 MFI; p = 0.004). CONCLUSIONS: Plasma BLVRB was associated with IPH and increased risk of recurrent ischemic stroke in patients with symptomatic low- to moderate-grade carotid stenosis, indicating the capacity to monitor the efficacy of IPH-preventive pharmacotherapy in an animal model. Together, these results suggest the utility of plasma BLVRB as a biomarker for atherosclerotic plaque instability.

A novel animal model for vulnerable atherosclerotic plaque: dehydrated ethanol lavage in the carotid artery of rabbits fed a Western diet.

BACKGROUND: The study of unstable atherosclerotic plaques is limited by the absence of ideal animal models to reproduce the plaque instability observed in humans. In this study, we attempted to develop a novel animal model for vulnerable atherosclerotic plaques using dehydrated ethanol lavage in rabbits fed a Western diet (WD). METHODS: A total of 30 New Zealand White (NZW) rabbits were randomized to 5 groups, including a control group with or without WD, a balloon injury with WD group, and an ethanol injury with or without WD group. Operations were conducted using the right common carotid artery as the target vessel. All animals were followed up for 3 months unless a vascular event occurred. Blood samples and carotid artery specimens were ultimately collected for analysis of atherogenesis. RESULTS: Compared to rabbits in which lesions were induced by balloon injury, those subjected to an ethanol lavage with high cholesterol diet showed progressive atherosclerotic lesions in all carotid artery segments, which were characterized by greater plaque burden, smaller minimum lumen area (MLA), and increased vulnerability as indicated by abundant macrophages, scattered smooth muscle cell (SMC) composition, higher matrix metalloproteinase-9 (MMP-9) expression in plaques, thinner fibrous cap thickness, and higher possibility of stroke event (50% vs. 0%). Meanwhile, the serum interleukin-1ß (IL-1ß) and monocyte chemoattractant protein-1 (MCP-1) levels in the ethanol injury group with a high-cholesterol diet were significantly higher than those in the balloon injury group after 3 months (all P<0.01). CONCLUSIONS: We successfully established a novel animal model for vulnerable atherosclerosis by ethanol exposure of the carotid segment that has a higher predictive value for the probability of ischemic events than the balloon injury model. Therefore, it may represent a promising animal model for investigating new therapeutic approaches, novel imaging modalities, and underlying mechanisms for vulnerable atherosclerotic plaque.

A Non-Invasive Nanoprobe for In Vivo Photoacoustic Imaging of Vulnerable Atherosclerotic Plaque.

Vulnerable atherosclerotic (AS) plaque is the major cause of cardiovascular death. However, clinical methods cannot directly identify the vulnerable AS plaque at molecule level. Herein, osteopontin antibody (OPN Ab) and NIR fluorescence molecules of ICG co-assembled Ti3 C2 nanosheets are reported as an advanced nanoprobe (OPN Ab/Ti3 C2 /ICG) with enhanced photoacoustic (PA) performance for direct and non-invasive in vivo visual imaging of vulnerable AS plaque. The designed OPN Ab/Ti3 C2 /ICG nanoprobes successfully realize obvious NIR fluorescence imaging toward foam cells as well as the vulnerable AS plaque slices. After intravenous injection of OPN Ab/Ti3 C2 /ICG nanoprobes into AS model mice, in vivo imaging results show a significantly enhanced PA signal in the aortic arch accumulated with vulnerable plaque, well indicating the remarkable feasibility of OPN Ab/Ti3 C2 /ICG nanoprobes to distinguish the vulnerable AS plaque. The proposed OPN Ab/Ti3 C2 /ICG nanoprobes not only overcome the clinical difficulty to differentiate vulnerable plaque, but also achieve the non-invasively specific in vivo imaging of vulnerable AS plaque at molecule level, greatly promoting the innovation of cardiovascular diagnosis technology.

MicroRNA-9 overexpression suppresses vulnerable atherosclerotic plaque and enhances vascular remodeling through negative regulation of the p38MAPK pathway via OLR1 in acute coronary syndrome.

Acute coronary syndrome (ACS) is characterized by atherosclerotic plaque rupture with a high incidence of recurrent ischemic events. Several microRNAs are found to be aberrantly expressed in atherosclerotic plaques. This study aims to investigate the effects of microRNA-9 (miR-9) on vulnerable atherosclerotic plaque and vascular remodeling in ACS and underlying mechanisms. Microarray-based gene expression profiling was used to identify differentially expressed genes related to ACS and regulatory miRNAs. Oxidized low-density lipoprotein (lectin-like) receptor 1 (OLR1) was identified to be aberrantly activated in ACS and regulated by miR-9. OLR1 was verified as a target gene of miR-9 by bioinformatics prediction and dual luciferase reporter gene assay. The atherosclerotic models were induced in ApoE-/- mice, in which the agomir or antagomir of miR-9, or small interfering RNA (siRNA) against OLR1 were separately introduced. Serum lipid levels and expression of vascular remodeling and inflammatory response-related factors were determined, respectively. On the basis of the obtained results, in the atherosclerosis mice treated with the agomir of miR-9 and siRNA against OLR1, the p38-mitogen-activated protein kinase (p38MAPK) pathway was inhibited; levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, tumor necrosis factor-α, interleukin-6, and vascular endothelial growth factor were reduced, but the high-density lipoprotein cholesterol level was increased, along with decreased vulnerable atherosclerotic plaque area and enhanced vascular remodeling. Taken together, these findings suggested an inhibitory role miR-9 acts in the formation of vulnerable atherosclerotic plaques in ACS mice, along with a promoted vascular remodeling, via a negative feedback regulation of OLR1-mediated p38MAPK pathway.

Optical/MRI dual-modality imaging of M1 macrophage polarization in atherosclerotic plaque with MARCO-targeted upconversion luminescence probe.

Pro-inflammatory M1 macrophage is identified as a prominent component initializing the progress of vulnerable atherosclerotic plaque. Here, we constructed anti-MARCO NaGdF4:Yb,Er@NaGdF4 upconversion nanoparticles (UCNPs) by conjugating polyclonal MARCO antibody to the surface of NaGdF4:Yb,Er@NaGdF4via condensation reaction. UCNPs displayed highly mono-dispersion with average sizes of 26.7 ±â€¯0.8 nm and favorable biocompatibility. In vivo upconversion optical imaging revealed that distinctive fluorescence signal could be observed in the regions of carotid artery 10 min post-injection, reached peak value at 1 h and decreased back to baseline at 24 h post-injection. The carotid artery wall demonstrated high signal intensity on T1-weighted MR images after anti-MARCO UCNPs injection, as determined by 7.0T MRI. Immunofluorescence staining of tissue section of carotid artery revealed that MARCO was highly abundant in shoulder regions of plaque. Anti-MARCO UCNPs is a promising optical/MRI dual-modality imaging probe which can non-invasively reflect M1 phenotype macrophages behavior in vivo.

Pollen Typhae Total Flavone Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis in Human Aortic-Vascular Smooth Muscle Cells through Down-Regulating PERK-eIF2α-ATF4-CHOP Pathway.

OBJECTIVE: To test the hypothesis that the inhibition of endoplasmic reticulum (ER) stress-induced apoptosis in oxidized low-density lipoproteins (ox-LDL)-induced human aortic-vascular smooth muscle cells (HA-VSMCs) was associated with suppression of the protein kinase RNA-like ER kinase (PERK)-eukaryotic translation initiation factor 2α (eIF2α)-activating transcription factor 4 (ATF4)-CCAAT/enhancer binding protein homologous protein (CHOP) signaling pathway by Pollen Typhae total flavone (PTF). METHODS: Primary HA-VSMCs were cultured and identified. The cultured HA-VSMCs were randomized into 5 groups, including a normal control group, an ox-LDL group (70 µg/mL high ox-LDL), an HPTF group (70 µg/mL high ox-LDL+500 µg/mL PTF), an MPTF group (70 µg/mL high ox-LDL+250 µg/mL PTF), and a LPTF group (70 µg/mL high ox-LDL+100 µg/mL PTF) in the first part; and a normal control group, an ox-LDL group (70 µg/mL high ox-LDL), an MPTF group (70 µg/mL high ox-LDL+250 µg/mL PTF), a shRNA group (transducted with PERK shRNA lentiviral particles), a scramble shRNA group (transducted with control shRNA lentiviral particles), an MPTF+ox-LDL+shRNA group (250 µg/mL PTF+70 µg/mL high ox-LDL+PERK shRNA lentiviral particles) and an ox-LDL+shRNA group (70 µg/mL high ox-LDL+PERK shRNA lentiviral particles) in the second part. The protein expression levels of ER-associated apoptosis proteins were detected by Western blot, and their mRNA expression levels were detected by quantitative real-time reverse transcription-polymerase chain reaction. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was applied to test cell viability, and the level of apoptosis was monitored by flow cytometry. RESULTS: The MTT assay and flow cytometry showed that the ox-LDL group had a significant increase in apoptosis, which was attenuated in PTF treatment groups and shRNA groups. Moreover, the ox-LDL group had increased protein and mRNA levels of binding immunoglobulin protein and ER-associated apoptosis proteins, such as PERK, eIF2α, ATF4 and CHOP, which were attenuated in PTF treatment groups and shRNA groups. CONCLUSIONS: The apoptosis induced by ox-LDL had a strong relation to ER stress. The protective effect of PTF on ER stressinduced apoptosis was associated with inhibition of the PERK-eIF2α-ATF4-CHOP pathway, which might be a potential therapeutic strategy for enhancing the stability of atherosclerotic plaques.

Downregulated microRNA-224 aggravates vulnerable atherosclerotic plaques and vascular remodeling in acute coronary syndrome through activation of the TGF-ß/Smad pathway.

Recent studies have shown that circulating microRNAs (miRNA) play a critical role in diagnosing acute coronary syndrome (ACS). This study aims to investigate the effect of miR-224 on atherosclerotic plaques forming and vascular remodeling in ACS and its relationship with TGF-ß/Smad pathway. Myocardial infarction (MI) rat model was established and lentivirus vector of miR-224 inhibitor was prepared for investigating the effect of downregulated miR-224 on the contents of nitric oxide (NO) and endothelin-1 (ET-1), blood lipid levels and inflammatory factor levels in serum as well as the TGF-ß/Smad pathway. The rats suffering from MI had decreased survival rates and exhibited reduced levels of NO, high-density lipoprotein cholesterol, and lumen diameter, and Smad7 messenger RNA (mRNA) and protein expression; while had significantly increased ratio of heart weight or body weight, levels of ET-1, inflammatory factors, blood lipid indexes, vascular remodeling indexes, collagen volume fraction, vulnerable atherosclerotic plaque area, VCAM-1 and MMP-2 protein expression, TGF-ß, Smad2, Smad3, and Smad4 mRNA and protein expression. After inhibiting the TGF-ß/Smad pathway, the rats suffering from MI showed notably opposite trend. In conclusion, downregulation of miR-224 expression promotes the formation of vulnerable atherosclerotic plaques and vascular remodeling in ACS through activation of the TGF-ß/Smad pathway. Therefore, this study provides a new therapeutic target for ACS.

18F-sodium fluoride positron emission tomography assessed microcalcifications in culprit and non-culprit human carotid plaques.

BACKGROUND: 18F-NaF positron emission tomography (PET) targets microcalcifications. We compared in vitro microPET assessed 18F-NaF uptake between culprit and non-culprit human carotid plaques. Furthermore, we compared 18F-NaF uptake with calcification visualized on microcomputed tomography (microCT). METHODS: Carotid plaques from stroke patients undergoing surgery were incubated in 18F-NaF and scanned using a microPET and a microCT scan. The average PET assessed 18F-NaF uptake was expressed as percentage of the incubation dose per gram (%Inc/g). 18F-NaF PET volume of interest (VOI) was compared with CT calcification VOI. RESULTS: 23 carotid plaques (17 culprit, 6 non-culprit) were included. The average 18F-NaF uptake in culprit carotid plaques was comparable with the uptake in non-culprit carotid plaques (median 2.32 %Inc/g [IQR 1.98 to 2.81] vs. median 2.35 %Inc/g [IQR 1.77 to 3.00], P = 0.916). Only a median of 10% (IQR 4 to 25) of CT calcification VOI showed increased 18F-NaF uptake, while merely a median of 35% (IQR 6 to 42) of 18F-NaF PET VOI showed calcification on CT. CONCLUSIONS: 18F-NaF PET represents a different stage in the calcification process than CT. We observed a similar PET assessed 18F-NaF uptake and pattern in culprit and non-culprit plaques of high-risk patients, indicating that this method may be of more value in early atherosclerotic stenosis development.

Imaging the event-prone coronary artery plaque.

Acute coronary events, the dreaded manifestation of coronary atherosclerosis, remain one of the main contributors to mortality and disability in the developed world. The majority of those events are associated with atherosclerotic plaques-related thrombus formation following an acute disruption, that being rupture or erosion, of an event-prone lesion. These historically termed vulnerable plaques have been the target of numerous benchtop and clinical research endeavors, yet to date without solid results that would allow for early identification and potential treatment. Technological leaps in cardiovascular imaging have provided novel insights into the formation and role of the event-prone plaques. From intracoronary optical coherence tomography that has enhanced our understanding of the pathophysiological mechanisms of plaque disruption, over coronary computed tomography angiography that enables non-invasive serial plaque imaging, and positron emission tomography poised to be rapidly implemented into clinical practice to the budding field of plaque imaging with cardiac magnetic resonance, we summarize the invasive and non-invasive imaging modalities currently available in our armamentarium. Finally, the current status and potential future imaging directions are critically appraised.

Pollen Typhae Total Flavone Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis in Human Aortic-Vascular Smooth Muscle Cells through Down-Regulating PERK-eIF2α-ATF4-CHOP Pathway / 中国结合医学杂志

OBJECTIVE@#To test the hypothesis that the inhibition of endoplasmic reticulum (ER) stress-induced apoptosis in oxidized low-density lipoproteins (ox-LDL)-induced human aortic-vascular smooth muscle cells (HA-VSMCs) was associated with suppression of the protein kinase RNA-like ER kinase (PERK)-eukaryotic translation initiation factor 2α (eIF2α)-activating transcription factor 4 (ATF4)-CCAAT/enhancer binding protein homologous protein (CHOP) signaling pathway by Pollen Typhae total flavone (PTF).@*METHODS@#Primary HA-VSMCs were cultured and identified. The cultured HA-VSMCs were randomized into 5 groups, including a normal control group, an ox-LDL group (70 μg/mL high ox-LDL), an HPTF group (70 μg/mL high ox-LDL+500 μg/mL PTF), an MPTF group (70 μg/mL high ox-LDL+250 μg/mL PTF), and a LPTF group (70 μg/mL high ox-LDL+100 μg/mL PTF) in the first part; and a normal control group, an ox-LDL group (70 μg/mL high ox-LDL), an MPTF group (70 μg/mL high ox-LDL+250 μg/mL PTF), a shRNA group (transducted with PERK shRNA lentiviral particles), a scramble shRNA group (transducted with control shRNA lentiviral particles), an MPTF+ox-LDL+shRNA group (250 μg/mL PTF+70 μg/mL high ox-LDL+PERK shRNA lentiviral particles) and an ox-LDL+shRNA group (70 μg/mL high ox-LDL+PERK shRNA lentiviral particles) in the second part. The protein expression levels of ER-associated apoptosis proteins were detected by Western blot, and their mRNA expression levels were detected by quantitative real-time reverse transcription-polymerase chain reaction. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was applied to test cell viability, and the level of apoptosis was monitored by flow cytometry.@*RESULTS@#The MTT assay and flow cytometry showed that the ox-LDL group had a significant increase in apoptosis, which was attenuated in PTF treatment groups and shRNA groups. Moreover, the ox-LDL group had increased protein and mRNA levels of binding immunoglobulin protein and ER-associated apoptosis proteins, such as PERK, eIF2α, ATF4 and CHOP, which were attenuated in PTF treatment groups and shRNA groups.@*CONCLUSIONS@#The apoptosis induced by ox-LDL had a strong relation to ER stress. The protective effect of PTF on ER stressinduced apoptosis was associated with inhibition of the PERK-eIF2α-ATF4-CHOP pathway, which might be a potential therapeutic strategy for enhancing the stability of atherosclerotic plaques.

Hybrid PET/CT and PET/MRI imaging of vulnerable coronary plaque and myocardial scar tissue in acute myocardial infarction.

BACKGROUND: Following an acute coronary syndrome, combined CT and PET with 18F-NaF can identify coronary atherosclerotic plaques that have ruptured or eroded. However, the processes behind 18F-NaF uptake in vulnerable plaques remain unclear. METHODS AND RESULTS: Ten patients with STEMI were scanned after 18F-NaF injection, for 75 minutes in a Siemens PET/MR scanner using delayed enhancement (LGE). They were then scanned in a Siemens PET/CT scanner for 10 minutes. Tissue-to-background ratio (TBR) was compared between the culprit lesion in the IRA and remote non-culprit lesions in an effort to independently validate prior studies. Additionally, we performed a proof-of-principle study comparing TBR in scar tissue and remote myocardium using LGE images and PET/MR or PET/CT data. From the 33 coronary lesions detected on PET/CT, TBRs for culprit lesions were higher than for non-culprit lesions (TBR = 2.11 ± 0.45 vs 1.46 ± 0.48; P < 0.001). Interestingly, the TBR measured on the PET/CT was higher for infarcted myocardium than for remote myocardium (TBR = 0.81 ± 0.10 vs 0.71 ± 0.05; P = 0.003). These results were confirmed using the PET/MR data (TBR = 0.81 ± 0.10 for scar, TBR = 0.71 ± 0.06 for healthy myocardium, P = 0.03). CONCLUSIONS: We confirmed the potential of 18F-NaF PET/CT imaging to detect vulnerable coronary lesions. Moreover, we demonstrated proof-of-principle that 18F-NaF concurrently detects myocardial scar tissue.

αVß3 integrin-targeted microSPECT/CT imaging of inflamed atherosclerotic plaques in mice.

BACKGROUND: αVß3-integrin is expressed by activated endothelial cells and macrophages in atherosclerotic plaques and may represent a valuable marker of high-risk plaques. We evaluated (99m)Tc-maraciclatide, an integrin-specific tracer, for imaging vascular inflammation in atherosclerotic lesions in mice. METHODS: Apolipoprotein E-negative (ApoE(-/-)) mice on a Western diet (n = 10) and normally fed adult C57BL/6 control mice (n = 4) were injected with (99m)Tc-maraciclatide (51.8 ± 3.7 MBq). A blocking peptide was infused in three ApoE(-/-) mice; this condition served as another control. After 90 min, the animals were imaged via single-photon emission computed tomography (SPECT). While maintained in the same position, the mice were transferred to computed tomography (CT) to obtain contrast-enhanced images of the aortic arch. Images from both modalities were fused, and signal was quantified in the aortic arch and in the vena cava for subtraction of blood-pool activity. The aorta was carefully dissected after imaging for gamma counting, autoradiography, and histology. RESULTS: Tracer uptake was significantly higher in ApoE(-/-) mice than in both groups of control mice (1.56 ± 0.33 vs. 0.82 ± 0.24 vs. 0.98 ± 0.11, respectively; P = 0.006). Furthermore, higher tracer activity was detected via gamma counting in the aorta of hypercholesterolemic mice than in both groups of control mice (1.52 ± 0.43 vs. 0.78 ± 0.19 vs. 0.47 ± 0.31 (99m)Tc-maraciclatide %ID/g, respectively; P = 0.018). Autoradiography showed significantly higher tracer uptake in the atherosclerotic aorta than in the control aorta (P = 0.026). Finally, in the atherosclerotic aorta, immunostaining indicated that the integrin signal came predominantly from macrophages and was correlated with the macrophage CD68 immunomarker (r = 0.73). CONCLUSIONS: (99m)Tc-maraciclatide allows in vivo detection of inflamed atherosclerotic plaques in mice and may represent a non-invasive approach for identifying high-risk plaques in patients.

Review of cardiovascular imaging in the journal of nuclear cardiology in 2015. Part 1 of 2: Plaque imaging, positron emission tomography, computed tomography, and magnetic resonance.

In 2015, many original articles pertaining to cardiovascular imaging with impressive quality were published in the Journal of Nuclear Cardiology. In a set of 2 articles, we provide an overview of these contributions to facilitate for the interested reader a quick review of the advancements that occurred in the field over this year. In this first article, we focus on arterial plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance imaging.

Feasibility of [18F]-RGD for ex vivo imaging of atherosclerosis in detection of αvß3 integrin expression.

BACKGROUND: Inflammation and angiogenesis play an important role in atherosclerotic plaque rupture. Therefore, molecular imaging of these processes could be used for determination of rupture-prone atherosclerotic plaques. αvß3 integrin is involved in the process of angiogenesis. Targeted imaging of αvß3 integrin has been shown to be possible in previous studies on tumor models, using radiolabeled arginine-glycine-aspartate (RGD). Our aim was to investigate feasibility of ex vivo detection of αvß3 integrin in carotid endarterectomy (CEA) specimens. METHODS AND RESULTS: Nineteen CEA specimens were incubated in 5 MBq [18F]-RGD-K5 for 1 hour followed by 1 hour emission microPET scan. The results were quantified in 4 mm wide segments as percent incubation dose per gram (%Inc/g). Segmental-to-total ratio was calculated and presence of αvß3 integrin and endothelial cells in each segment was confirmed by immunohistochemical staining for CD31 and αvß3 integrin, respectively. [18F]-RGD-K5 uptake was heterogeneously distributed across CEA specimens and was localized within the vessel wall. Significant correlations were observed between segmental-to-total ratio with αvß3 integrin staining score (r = 0.58, P = .038) and CD31 staining score (ρ = 0.67, P < .002). CONCLUSION: This study showed the feasibility of integrin imaging by determination of αvß3 integrin expression in human atherosclerotic plaques.

Assessment of RANTES levels as the indicators of plaque vulnerability in rabbit models of atherosclerosis.

The aim of the present study was to determine the chemokine RANTES (regulated on activation, normal T-cell expressed, and secreted) levels in plasma and atherosclerotic plaques and to assess their diagnostic efficacy in the evaluation of vulnerable plaques. The rabbit models of vulnerable atherosclerotic plaque (VAP) were established by high fat diet and pharmaceutical triggering. The serum RANTES levels of VAP group (91.97 ± 8.51 ng/ml) were significantly higher than those of AS (atherosclerosis) group (50.03 ± 2.92 ng/ml). Consistently, the mRNA and protein of RANTES in vulnerable atherosclerotic plaques were also obviously up-regulated compared to AS group (P < 0.01). Moreover, corrected plaque area and vulnerability index of VAP group proved to be significantly higher than AS group. The correlation coefficient between RANTES and plaque vulnerability indicated that RANTES, especially plaque RANTES, was positively correlated with VAP. In addition, increased expression of nuclear factor kappa B p65 (NF-κB p65) was observed in VAP group compared to AS group (P < 0.05), which partly accounted for the increased RANTES levels. In conclusion, positive associations between RANTES and plaque vulnerability suggest that higher RANTES levels may be associated with atherosclerosis and high-risk plaques. Our study highlights the utility of both serum and plaque RANTES levels as indicators of plaque vulnerability in the field of preventive cardiology.

In vivo molecular imaging of atherosclerotic lesions in ApoE-/- mice using VCAM-1-specific, 99mTc-labeled peptidic sequences.

UNLABELLED: Vascular cell adhesion molecule 1 (VCAM-1) plays a major role in the chronic inflammatory processes involved in vulnerable atherosclerotic plaque development. We previously showed that the (99m)Tc-labeled major histocompatibility complex 1-derived peptide B2702p bound specifically to VCAM-1 and allowed the ex vivo imaging of atherosclerotic lesions in Watanabe heritable hyperlipidemic rabbits. However, B2702p target-to-background ratio was suboptimal for the in vivo imaging of VCAM-1 expression in atherosclerotic lesions. To improve the target-to-background ratio, 20 derivatives of B2702p (B2702p1-B2702p20) were synthesized using the alanine scan methodology. We hypothesized that (99m)Tc-radiolabeled B2702p derivatives might allow the molecular imaging of VCAM-1 expression in an experimental model of atherosclerosis. METHODS: A mouse model of focal atherosclerotic plaque development induced by left carotid artery ligation in apolipoprotein E double-knockout (ApoE(-/-)) mice was used (n = 82). (99m)Tc-B2702p and (99m)Tc-B2702p1-(99m)Tc-B2702p20 were injected intravenously in anesthetized animals 3 wk after the ligation. Whole-body planar imaging was performed for 3 h. SPECT imaging of 6 additional ligated ApoE(-/-) mice was also performed with (99m)Tc-B2702p1. The animals were then euthanized, and the biodistribution of (99m)Tc-labeled peptides was evaluated by γ-well counting of excised organs. Expression of VCAM-1 in the ligated and contralateral carotid arteries was evaluated by immunohistology. RESULTS: Robust VCAM-1 immunostaining was observed in the left carotid atherosclerotic lesions as a consequence of artery ligation, whereas no VCAM-1 expression was detected in the contralateral carotid artery. Among all evaluated peptides, (99m)Tc-B2702p1 exhibited the most favorable properties. By γ-well counting, there was a significant 2.0-fold increase in the (99m)Tc-B2702p1 left-to-right carotid artery activity ratio (2.6 ± 0.6) and a 3.4-fold increase in the left carotid-to-blood activity ratio (1.4 ± 0.4) in comparison to (99m)Tc-B2702p (1.3 ± 0.2 and 0.4 ± 0.1, respectively, P < 0.05 for both comparisons). Similarly, planar image quantification indicated a higher left-to-right carotid activity ratio in (99m)Tc-B2702p1- than in (99m)Tc-B2702p-injected mice (1.2 ± 0.1 vs. 1.0 ± 0.0, respectively, P < 0.05). Finally, a significantly higher (99m)Tc-B2702p1 activity in the left than in the right carotid artery was observed by SPECT imaging (2.2 ± 0.4 vs. 1.4 ± 0.3 cpm/mm(2)/injected dose, respectively, P < 0.05). CONCLUSION: (99m)Tc-B2702p1 is a potentially useful radiotracer for the in vivo molecular imaging of VCAM-1 expression in atherosclerotic plaques.

Atherosclerosis, platelets and thrombosis in acute ischaemic heart disease.

Atherosclerosis is the underlying reason for nearly all causes of coronary artery disease and peripheral arterial disease and many cases of stroke. Atherosclerosis is a systemic inflammatory process characterised by the accumulation of lipids and macrophages/lymphocytes within the intima of large arteries. The deposition of these blood borne materials and the subsequent thickening of the wall often significantly compromise the residual lumen leading to ischaemic events distal to the arterial stenosis. However, these initial fatty streak lesions may also evolve into vulnerable plaques susceptible to rupture or erosion. Plaque disruption initiates both platelet adhesion and aggregation on the exposed vascular surface and the activation of the clotting cascade leading to the so-called atherothrombotic process. Yet, platelets have also been shown to be transporters of regulatory molecules (micro-RNA), to drive the inflammatory response and mediate atherosclerosis progression. Here we discuss our current understanding of the pathophysiological mechanisms involved in atherogenesis - from fatty streaks to complex and vulnerable atheromas - and highlight the molecular machinery used by platelets to regulate the atherogenic process, thrombosis and its clinical implications.

MRI with multiple contrast weightings and dynamic contrast enhancement in evaluation of vulnerable atherosclerotic plaques / 上海第二医科大学学报

Objective To analyze the utility of MRI with multiple contrast and dynamic contrast weightings enhancement(DCE) in evaluation of vulnerable atherosclerotic plaques. Methods Forty male New Zealand white rabbits were fed with hypercholesterolemic diet,and right iliac arteries including the common and external iliac arteries were examined by multiple contrast and DCE MRI at intervals 6 to 20 weeks after balloon denudation.For multiple contrast weightings scanning,T1-,T1-/T2WI with fat suppression,proton density weighted and double invention recovery were used.Meanwhile,post DCE T1-with fat suppression images were obtained in 1,5,15 and 25 min after a bolus injection of Gd-DTPA contrast agent.Then a comparative analysis of plaque morphology and components to images was performed. Results There were 34(42.5%) vulnerable plaques and 46(57.5%) stable plaques amomg the 80 atherosclerotic lesions located at the right common or external iliac arteries.The accuracy,sensitivity and specificity of MRI with multiple contrast weightings and DCE for the detection of vulnerable plaques were 87.5%,94.1% and 82.6%,respectively,significantly higher than those only with multiple contrast weightings,which were 73.8%,82.3% and 67.4%,respectively(P