Intraplaque hemorrhage and progression of coronary atheroma

Platelets as an inter-player between hyperlipidaemia and atherosclerosis

Platelet hyperreactivity and hyperlipidaemia contribute significantly to atherosclerosis. Thus, it is desirable to review the platelet-hyperlipidaemia interplay and its impact on atherogenesis. Native low-density lipoprotein (nLDL) and oxidized LDL (oxLDL) are the key proatherosclerotic components of hyperlipidaemia. nLDL binds to the platelet-specific LDL receptor (LDLR) ApoE-R2', whereas oxLDL binds to the platelet-expressed scavenger receptor CD36, lectin-type oxidized LDLR 1 and scavenger receptor class A 1. Ligation of nLDL/oxLDL induces mild platelet activation and may prime platelets for other platelet agonists. Platelets, in turn, can modulate lipoprotein metabolisms. Platelets contribute to LDL oxidation by enhancing the production of reactive oxygen species and LDLR degradation via proprotein convertase subtilisin/kexin type 9 release. Platelet-released platelet factor 4 and transforming growth factor β modulate LDL uptake and foam cell formation. Thus, platelet dysfunction and hyperlipidaemia work in concert to aggravate atherogenesis. Hypolipidemic drugs modulate platelet function, whereas antiplatelet drugs influence lipid metabolism. The research prospects of the platelet-hyperlipidaemia interplay in atherosclerosis are also discussed.

Macrophage Ferroptosis Promotes MMP2/9 Overexpression Induced by Hemin in Hemorrhagic Plaque

BACKGROUND

 Intra-plaque hemorrhage (IPH) leads to rapid plaque progression and instability through upregulation of matrix metalloproteinases (MMPs) and collagen degradation. Hemoglobin-derived hemin during IPH promotes plaque instability. We investigated whether hemin affects MMP overexpression in macrophages and explored the underlying mechanisms.

MATERIAL AND METHODS

 In vivo, hemorrhagic plaque models were established in rabbits and ApoE-/- mice. Ferrostatin-1 was used to inhibit ferroptosis. Plaque size, collagen, and MMP2/9 levels were evaluated using immunohistochemistry, H&E, Sirius Red, and Masson staining. In vitro, mouse peritoneal macrophages were extracted. Western blot and ELISA were used to measure MMP2/9 levels. Bioinformatics analysis investigated the association between MMPs and ferroptosis pathway genes. Macrophage ferroptosis was assessed by evaluating cell viability, lipid reactive oxygen species, mitochondrial ultrastructure, iron content, and COX2 levels after pretreatment with cell death inhibitors. Hemin's impact on ferroptosis and MMP expression was studied using Ferrostatin-1 and SB202190.

RESULTS

 In the rabbit hemorrhagic plaques, hemin deposition and overexpression of MMP2/9 were observed, particularly in macrophage-enriched regions. In vitro, hemin induced ferroptosis and MMP2/9 expression in macrophages. Ferrostatin-1 and SB202190 inhibited hemin-induced MMP2/9 overexpression. Ferrostatin-1 inhibited p38 phosphorylation in macrophages. Ferostatin-1 inhibits macrophage ferroptosis, reduces MMP2/9 levels in plaques, and stabilizes the hemorrhagic plaques.

CONCLUSION

 Our results suggested that hemin-induced macrophage ferroptosis promotes p38 pathway activation and MMP2/9 overexpression, which may play a crucial role in increasing hemorrhagic plaque vulnerability. These findings provide insights into the pathogenesis of hemorrhagic plaques and suggest that targeting macrophage ferroptosis may be a promising strategy for stabilizing vulnerable plaque.

Unlocking the link between haptoglobin polymorphism and noninfectious human diseases: insights and implications

Haptoglobin (Hp) is a polymorphic protein that was initially described as a hemoglobin (Hb)-binding protein. The major functions of Hp are to scavenge Hb, prevent iron loss, and prevent heme-based oxidation. Hp regulates angiogenesis, nitric oxide homeostasis, immune responses, and prostaglandin synthesis. Genetic polymorphisms in the Hp gene give rise to different phenotypes, including Hp 1-1, Hp 2-1, and Hp 2-2. Extensive research has been conducted to investigate the association between Hp polymorphisms and several medical conditions including cardiovascular disease, inflammatory bowel disease, cancer, transplantation, and hemoglobinopathies. Generally, the Hp 2-2 phenotype is associated with increased disease risk and poor outcomes. Over the years, the Hp 2 allele has spread under genetic pressures. Individuals with the Hp 2-2 phenotype generally exhibit lower levels of CD163 expression in macrophages. The decreased expression of CD163 may be associated with the poor antioxidant capacity in the serum of subjects carrying the Hp 2-2 phenotype. However, the Hp 1-1 phenotype may confer protection in some cases. The Hp1 allele has strong antioxidant, anti-inflammatory, and immunomodulatory properties. It is important to note that the benefits of the Hp1 allele may vary depending on genetic and environmental factors as well as the specific disease or condition under consideration. Therefore, the Hp1 allele may not necessarily confer advantages in all situations, and its effects may be context-dependent. This review highlights the current understanding of the role of Hp polymorphisms in cardiovascular disease, inflammatory bowel disease, cancer, transplantation, hemoglobinopathies, and polyuria.

Arterial Adventitial Vasa Vasorum Hyperplasia involved in Atherosclerotic Plaque Formation in a Rabbit Model

OBJECTIVE

It was previously believed that atherosclerotic (AS) plaque starts to develop from the intima and that intraplaque vasa vasorum (VV) hyperplasia promotes adventitial VV (AVV) hyperplasia. However, recent studies have shown that arterial AVV hyperplasia precedes early intimal thickening, suggesting its possible role as an initiating factor of AS. To provide further insight into this process, in this study, we examine the evolution of AAV and VV development in a preclinical model of early AS with longitudinal ultrasound imaging.

METHODS

Models of early AS were established. Duplex ultrasound scanning and contrast-enhanced ultrasound were performed for diagnosis. Pearson correlation tests were used to analyze the relationships between AVV hyperplasia and VV hyperplasia, or between AVV hyperplasia and intima-media thickness (IMT).

RESULTS

During 0-12 wk of high-fat feeding, AVV gradually increased and intima-media thickened gradually in the observation area; in the 2nd wk of high-fat feeding, the observation area showed obvious AVV proliferation; at the 4th wk, the intima-media membrane became thicker; at the 12th wk, early plaque formation and intraplaque VV proliferation were observed. There was a strong positive correlation between AVV proliferation and IMT thickening and a strong negative correlation between AVV proliferation and the change rate of vessel diameter.

CONCLUSION

This study demonstrated that AVV proliferation in the arteries occurred earlier than IMT thickening and was positively correlated with IMT. At present, the indicators of ultrasonic diagnosis of AS, such as IMT, Intraplaque VV, Echo property, all appear in the advanced stage of AS. The AVV may be an innovative diagnostic target for the early stage of AS plaque.

MiR-127-3p enhances macrophagic proliferation via disturbing fatty acid profiles and oxidative phosphorylation in atherosclerosis

BACKGROUND

Atherosclerosis is a chronic pathology, leading to acute coronary heart disease or stroke. MiR-127 has been found significantly upregulated in advanced atherosclerosis. But its function in atherosclerosis remains unexplored. We explored the role of miR-127-3p in regulating atherosclerosis development and its downstream mechanisms.

METHODS

The expression profile of miR-127 in carotid atherosclerotic plaques of 23 patients with severe carotid stenosis was detected by RT-qPCR and in situ hybridization. Primary bone marrow-derived macrophages (BMDM) stimulated with oxidized low-density lipoprotein were used as an in vitro model. CCK-8, EdU, RT-qPCR, and flow cytometry were used to detect the proliferative capacity and polarization of BMDM, which were infected by lentivirus-carrying plasmid to upregulate or downregulate miR-127-3p expression, respectively. RNA sequencing combined with bioinformatic analysis and targeted fatty acid metabolomics approach were used to detect the transcriptome and lipid metabolites. The association between miR-127-3p and its target was verified by dual-luciferase activity reporting and Western blotting. Oxygen consumption rate of BMDM were detected using seahorse analysis. High-cholesterol-diet-fed low density lipoprotein deficient (LDLR-/-) mice, with-or-without carotid tandem-stenosis surgery, were treated with miR-127-3p agomir or antagomir to examine its effect on plaque development and stability.

RESULTS

miR-127-3p, not -5p, is elevated in human advanced carotid atheroma and its expression is positively associated with macrophage accummulation in plaques. In vitro, miR-127-3p-overexpressed macrophage exhibites increased proliferation capacity and facilitates M1 polariztion whereas the contrary trend is present in miR-127-3p-inhibited macrophage. Stearoyl-CoA desaturase-1 (SCD1) is one potential target of miR-127-3p. miR-127-3p mimics decreases the activity of 3' untranslated regions of SCD-1. Furthermore, miR-127-3p downregulates SCD1 expression, and reversing the expression of SCD1 attenuates the increased proliferation induced by miR-127-3p overexpression in macrophage. miR-127-3p overexpression could also lead to decreased content of unsaturated fatty acids(UFAs), increased content of acetyl CoA and increased level of oxidative phosphorylation. In vivo, miR-127-3p agomir significantly increases atherosclerosis progression, macrophage proliferation and decreases SCD1 expression and the content of UFAs in aortic plaques of LDLR-/- mice. Conversely, miR-127-3p antagomir attenuated atherosclerosis, macrophage proliferation in LDLR-/- mice, and enhanced carotid plaque stability in mice with vulnerable plaque induced.

CONCLUSION

MiR-127-3p enhances proliferation in macrophages through downregulating SCD-1 expression and decreasing the content of unsaturated fatty acid, thereby promoting atherosclerosis development and decreasing plaque stability. miR-127-3p/SCD1/UFAs might provide potential therapeutic target for anti-inflammation and atherosclerosis.

Layered plaque is associated with high levels of vascular inflammation and vulnerability in patients with stable angina pectoris

Layered plaque, a signature of previous plaque destabilization and healing, is a known predictor for rapid plaque progression; however, the mechanism of which is unknown. The aim of the current study was to compare the level of vascular inflammation and plaque vulnerability in layered plaques to investigate possible mechanisms of rapid plaque progression. This is a retrospective, observational, single-center cohort study. Patients who underwent both coronary computed tomography angiography (CTA) and optical coherence tomography (OCT) for stable angina pectoris (SAP) were selected. Plaques were defined as any tissue (noncalcified, calcified, or mixed) within or adjacent to the lumen. Perivascular inflammation was measured by pericoronary adipose tissue (PCAT) attenuation at the plaque levels on CTA. Features of plaque vulnerability were assessed by OCT. Layered plaques were defined as plaques presenting one or more layers of different optical densities and a clear demarcation from underlying components on OCT. A total of 475 plaques from 195 patients who presented with SAP were included. Layered plaques (n = 241), compared with non-layered plaques (n = 234), had a higher level of vascular inflammation (-71.47 ± 10.74 HU vs. -73.69 ± 10.91 HU, P = 0.026) as well as a higher prevalence of the OCT features of plaque vulnerability, including lipid-rich plaque (83.8% vs. 66.7%, P < 0.001), thin-cap fibroatheroma (26.1% vs. 17.5%, P = 0.026), microvessels (61.8% vs. 34.6%, P < 0.001), and cholesterol crystals (38.6% vs. 25.6%, P = 0.003). Layered plaque was associated with a higher level of vascular inflammation and a higher prevalence of plaque vulnerability, which might play an important role in rapid plaque progression.Clinical trial registration: https://classic.clinicaltrials.gov/ct2/show/NCT04523194 .

Pancoronary plaque characteristics in STEMI patients with rapid plaque progression: An optical coherence tomography study

BACKGROUND

Non-culprit plaque progression is associated with recurrent cardiac ischemic events and worse clinical outcomes. Given that atherosclerosis is a systemic disease, the pancoronary characteristics of patients with rapid plaque progression are unknown. This study aims to identify pancoronary plaque features in patients with ST-segment elevation myocardial infarction (STEMI) with and without rapid plaque progression, focused on the patient level.

METHODS AND RESULTS

From January 2017 to July 2019, 291 patients underwent 3-vessel optical coherence tomography imaging at the time of the primary procedure and a follow-up angiography interval of 12 months. The final analysis included 237 patients. Overall, 308 non-culprit lesions were found in 78 STEMI patients with rapid plaque progression, and 465 non-culprit plaques were found in 159 STEMI patients without rapid plaque progression. These patients had a higher pancoronary vulnerability (CLIMA-defined high-risk plaque: 47.4% vs. 33.3%; non-culprit plaque rupture: 25.6% vs. 14.5%) and a significantly higher prevalence of other vulnerable plaque characteristics (i.e., lipid-rich plaque, cholesterol crystal, microchannels, calcification, spotty calcification, and thrombus) at baseline versus those without rapid plaque progression. Lesions with rapid progression were highly distributed at the LAD, tending to be near the bifurcation. In multivariate analysis, age ≥ 65 years was an independent predictor of subsequent rapid lesion progression at the patient level, whereas microchannel, spotty calcification, and cholesterol crystal were independent predictors for STEMI patients ≥65 years old.

CONCLUSIONS

STEMI patients with subsequent rapid plaque progression had higher pancoronary vulnerability and commonly presented vulnerable plaque morphology. Aging was the only predictor of subsequent rapid plaque progression.

High-Risk Plaques on Coronary Computed Tomography Angiography: Correlation With Optical Coherence Tomography

BACKGROUND

Although patients with high-risk plaque (HRP) on coronary computed tomography angiography (CTA) are reportedly at increased risk for future cardiovascular events, individual HRP features have not been systematically validated against high-resolution intravascular imaging.

OBJECTIVES

The aim of this study was to correlate HRP features on CTA with plaque characteristics on optical coherence tomography (OCT).

METHODS

Patients who underwent both CTA and OCT before coronary intervention were enrolled. Plaques in culprit vessels identified by CTA were evaluated with the use of OCT at the corresponding sites. HRP was defined as a plaque with at least 2 of the following 4 features: positive remodeling (PR), low-attenuation plaque (LAP), napkin-ring sign (NRS), and spotty calcification (SC). Patients were followed for up to 3 years.

RESULTS

The study included 448 patients, with a median age of 67 years and of whom 357 (79.7%) were male, and 203 (45.3%) presented with acute coronary syndromes. A total of 1,075 lesions were analyzed. All 4 HRP features were associated with thin-cap fibroatheroma. PR was associated with all OCT features of plaque vulnerability, LAP was associated with lipid-rich plaque, macrophage, and cholesterol crystals, NRS was associated with cholesterol crystals, and SC was associated with microvessels. The cumulative incidence of the composite endpoint (target vessel nontarget lesion revascularization and cardiac death) was significantly higher in patients with HRP than in those without HRP (4.7% vs 0.5%; P = 0.010).

CONCLUSIONS

All 4 HRP features on CTA were associated with features of vulnerability on OCT. (Massachusetts General Hospital and Tsuchiura Kyodo General Hospital Coronary Imaging Collaboration; NCT04523194).

Red blood cell distribution width (RDW) is associated with unfavorable functional outcome after transfemoral transcatheter aortic valve implantation

Background

Red blood cell distribution width (RDW) is calculated in every blood count test and reflects variability in erythrocyte size. High levels mirror dysregulated erythrocyte homeostasis and have been associated with clonal hematopoiesis as well as higher mortality in several conditions.We aimed to determine the impact of preprocedural RDW levels on functional outcomes after transcatheter aortic valve implantation (TAVI).

Methods

In this single-center retrospective study, we analyzed 176 consecutive patients receiving TAVI between 2017 and 2021. RDW upper limit of normal was < 15 %. Patients were stratified according to preprocedural RDW as having normal or elevated values. We assessed all-cause-mortality and a composite endpoint comprising cardiovascular/ valve-related mortality and cardiovascular, valve-related and heart failure hospitalization at 1 year.

Results

43 patients (24.4 %) had RDW ≥ 15 %. There were significant baseline differences between groups (Society of Thoracic Surgeons - Predicted Risk of Mortality score 3.18 %[interquartile range 1.87-5.47] vs. 6.63 %[4.12-10.54] p < 0.001; hemoglobin 13.2 g/dL[11.8-14.1] vs. 10.4 g/dL[9.8-12.2], p < 0.001, RDW-normal vs. RDW-high, respectively). Age was not distinct (80.2 years [77.5-84.1] vs 81.2[71.3-84.7], p = 0.78). 1-year-all-cause mortality was not different (7.9 % vs. 9.4 %, p = 0.79). The RDW-high group showed markedly higher NT-proBNP levels after 1 year (647 ng/ml[283-1265] vs. 1893 ng/ml[744-5109], p = 0.005), and experienced more clinical endpoints (hazard ratio 2.57[1.28-5.16] for the composite endpoint, p = 0.006). RDW remained an independent predictor of the composite endpoint when accounting for all baseline differences in multivariable regression.

Conclusion

Elevated preprocedural RDW identifies patients at risk for impaired functional outcome after TAVI and may represent a useful low-cost parameter to guide intensity of outpatient surveillance strategies.

Association between Vascular Calcification and Intraplaque Hemorrhage in Coronary Atherosclerosis from Autopsy: The Hisayama Study

AIMS

Vascular calcification is observed in advanced atherosclerotic lesions. Vascular calcification is considered to increase the risk of intraplaque hemorrhage and subsequent plaque destabilization; however, there is limited pathohistoological evidence of the association between vascular calcification and intraplaque hemorrhage. The aim of this study was to investigate the association between vascular calcification and intraplaque hemorrhage in the coronary arteries.

METHODS

We examined 374 coronary arteries obtained from the autopsy samples of 126 deceased individuals. The vascular calcification levels of each artery were categorized into no calcification and quintiles of calcification area size among the arteries with calcification. Macrophage infiltration and neovascularization were also evaluated. The association of the calcification area, macrophage area, or number of vessels with the presence of intraplaque hemorrhage in the coronary arteries was estimated using a logistic regression analysis.

RESULTS

Calcification lesions were observed in 149 coronary arteries. Arteries in the fourth quintile of calcification area size had a significantly greater likelihood of intraplaque hemorrhage than the arteries without calcification, after adjusting for confounders: odds ratio 13.13 (95% confidence interval: 2.97-58.16). After evaluating the influence of macrophage infiltration, the highest odds ratio of intraplaque hemorrhage was associated with the combination of large macrophage area and moderately sized calicification areas. The odds ratio of intraplaque hemorrhage additively increased with the combination of calcification and the number of vessels.

CONCLUSIONS

The present findings suggest that vascular calcification is significantly associated with intraplaque hemorrhage. The association between vascular calcification and intraplaque hemorrhage may decrease above a certain size of the calcification area.

Pericarotid Fat Stranding at Computed Tomography Angiography: A Marker of the Short-Term Prognosis of Acute Ischemic Stroke

PURPOSE

Perivascular epicardial fat stranding detected in the coronary computed tomography (CT) angiography is associated with culprit lesions and provides helpful information on the risk of acute coronary syndrome. This study aimed to evaluate the potential clinical significance of pericarotid fat stranding (PCFS) and investigate the association between PCFS and short-term prognosis in acute stroke using head and neck CT angiography (CTA).

METHODS

This study included 80 patients (mean age, 69.69 ± 11.03; 58 men) who underwent both head and neck CTA and magnetic resonance imaging within a 1-week period. Baseline characteristics, pericarotid adipose tissue attenuation, plaque characteristics, ischemic penumbra, infarct core volume, infarct core growth rate (CGR), and the grade of collateral status were recorded and compared between a PCFS group and a non-PCFS group. Data were compared using the 2-sample t test, Mann-Whitney U test, Fisher exact test, and Spearman rank correlation analysis.

RESULTS

We found that patients with PCFS had a significantly higher pericarotid adipose tissue density than patients without PCFS (-55.75 ± 5.53 vs -65.82 ± 9.65, P < 0.001). Patients with PCFS showed a larger infarct core volume (166.43 ± 73.07 vs 91.43 ± 55.03, P = 0.001) and faster CGR (39.57 ± 12.01 vs 19.83 ± 32.77; P < 0.001), and the frequency of adverse prognosis was more significant than in control participants (83.33% vs 19.11%).

CONCLUSIONS

Individuals with PCFS showed higher CGR, which was substantially related to worse outcomes in patients with acute stroke with ipsilateral carotid atherosclerosis. Recognition of PCFS may help predict stroke prognosis and allow doctors to take early action to improve patient prognosis.

Invasive coronary imaging of inflammation to further characterize high-risk lesions: what options do we have?

Coronary atherosclerosis remains a leading cause of morbidity and mortality worldwide. The underlying pathophysiology includes a complex interplay of endothelial dysfunction, lipid accumulation and inflammatory pathways. Multiple structural and inflammatory features of the atherosclerotic lesions have become targets to identify high-risk lesions. Various intracoronary imaging devices have been developed to assess the morphological, biocompositional and molecular profile of the intracoronary atheromata. These techniques guide interventional and therapeutical management and allow the identification and stratification of atherosclerotic lesions. We sought to provide an overview of the inflammatory pathobiology of atherosclerosis, distinct high-risk plaque features and the ability to visualize this process with contemporary intracoronary imaging techniques.

Atherosclerotic plaque features relevant to rupture-risk detected by clinical photon-counting CT ex vivo: a proof-of-concept study

BACKGROUND

To identify subjects with rupture-prone atherosclerotic plaques before thrombotic events occur is an unmet clinical need. Thus, this proof-of-concept study aims to determine which rupture-prone plaque features can be detected using clinically available photon-counting computed tomography (PCCT).

METHODS

In this retrospective study, advanced atherosclerotic plaques (ex vivo, paraffin-embedded) from the Carotid Plaque Imaging Project were scanned by PCCT with reconstructed energy levels (45, 70, 120, 190 keV). Density in HU was measured in 97 regions of interest (ROIs) representing rupture-prone plaque features as demonstrated by histopathology (thrombus, lipid core, necrosis, fibrosis, intraplaque haemorrhage, calcium). The relationship between HU and energy was then assessed using a mixed-effects model for each plaque feature.

RESULTS

Plaques from five men (age 79 ± 8 [mean ± standard deviation]) were included in the study. Comparing differences in coefficients (b1diff) of matched ROIs on plaque images obtained by PCCT and histology confirmed that calcium was distinguishable from all other analysed features. Of greater novelty, additional rupture-prone plaque features proved discernible from each other, particularly when comparing haemorrhage with fibrous cap (p = 0.017), lipids (p = 0.003) and necrosis (p = 0.004) and thrombus compared to fibrosis (p = 0.048), fibrous cap (p = 0.028), lipids (p = 0.015) and necrosis (p = 0.017).

CONCLUSIONS

Clinically available PCCT detects not only calcification, but also other rupture-prone features of human carotid plaques ex vivo.

RELEVANCE STATEMENT

Improved atherosclerotic plaque characterisation by photon-counting CT provides the ability to distinguish not only calcium, but also rupture-prone plaque features such as haemorrhage and thrombus. This may potentially improve monitoring and risk stratification of atherosclerotic patients in order to prevent strokes.

KEY POINTS

• CT of atherosclerotic plaques mainly detects calcium. • Many components, such as intra-plaque haemorrhage and lipids, determine increased plaque rupture risk. • Ex vivo carotid plaque photon-counting CT distinguishes haemorrhage and thrombus. • Improved plaque photon-counting CT evaluation may refine risk stratification accuracy to prevent strokes.

Chronic Administration of Methamphetamine Aggravates Atherosclerotic Vulnerable Plaques in Apolipoprotein E Knockout Mice Fed with a High-cholesterol Diet

BACKGROUND

It has been observed previously that chronic methamphetamine (METH) administration could upregulate neuropeptide Y (NPY) expression and promote atherosclerotic formation in apolipoprotein E knockout (ApoE-/-) mice fed with a normal cholesterol or high diet and NPY might be involved in the pathogenesis of METHinduced atherogenic effects through NPY Y1 receptor pathway. Vulnerable coronary atherosclerotic plaque (VP) is a critical pathological finding responsible for the acute coronary syndrome (ACS). In this study, we explored whether METH abuse could aggravate the formation of VP in ApoE-/- mice fed with high cholesterol diet.

OBJECTIVE

The purpose of this study was to observe if chronic METH administration could aggravate vulnerable plaque (VP) formation in ApoE-/- mice fed with a highcholesterol diet.

METHODS

Male ApoE-/- mice fed with a high-cholesterol diet were intraperitoneally injected with normal saline (NS) or 8 mg/kg/day METH (M8) for 24 weeks. Body weight was monitored from baseline to 24 weeks at 2 weeks intervals. After 24 weeks of treatment, plasma lipid variables were measured. Movat's staining and immunohistochemical staining were performed on frozen sections of the aortic roots to calculate VP percentage and intraplaque hemorrhage (IPH) percentage and detect expression of NPY, vascular endothelial growth factor (VEGF), and CD31. In vitro, the expressions of Y2R, VEGF, and CD31 were detected by immunofluorescence staining in aortic endothelial cells incubated with PBS, 100μM METH, 10nmol NPY, or 100μM METH plus 10nmol NPY for 12 hours.

RESULTS

The CD31 positive area, percentage of IPH, VP, and the expressions of NPY and VEGF were significantly increased in the M8 group than in the NS group. In vitro, the expressions of Y2R, VEGF, and CD31 were significantly increased in the METH+NPY group than in the PBS, METH, and NPY groups and these effects could be blunted by treatment with a Y2R antagonist or DPPIV inhibitor.

CONCLUSION

Chronic METH administration could aggravate VP in ApoE-/- mice fed with a high-cholesterol diet, possibly through upregulating vascular NPY and VEGF expression and promoting angiogenesis and vessel rupture in atherosclerotic plaques. Our findings indicated that increased VP formation might contribute to the development of acute coronary syndrome post-chronic METH abuse by activating DPPIV/NPY/Y2R pathway.

Intraplaque Neovascularization, CD68+ and iNOS2+ Macrophage Infiltrate Intensity Are Associated with Atherothrombosis and Intraplaque Hemorrhage in Severe Carotid Atherosclerosis

BACKGROUND

Atherosclerosis is a progressive disease that results from endothelial dysfunction, inflammatory arterial wall disorder and the formation of the atheromatous plaque. This results in carotid artery stenosis and is responsible for atherothrombotic stroke and ischemic injury. Low-grade plaque inflammation determines biological stability and lesion progression.

METHODS

Sixty-seven cases with active perilesional inflammatory cell infiltrate were selected from a larger cohort of patients undergoing carotid endarterectomy. CD68+, iNOS2+ and Arg1+ macrophages and CD31+ endothelial cells were quantified around the atheroma lipid core using digital morphometry, and expression levels were correlated with determinants of instability: ulceration, thrombosis, plaque hemorrhage, calcification patterns and neovessel formation.

RESULTS

Patients with intraplaque hemorrhage had greater CD68+ macrophage infiltration (p = 0.003). In 12 cases where iNOS2 predominated over Arg1 positivity, the occurrence of atherothrombotic events was significantly more frequent (p = 0.046). CD31 expression, representing neovessel formation, correlated positively with atherothrombosis (p = 0.020).

CONCLUSIONS

Intraplaque hemorrhage is often described against the background of an intense inflammatory cell infiltrate. Atherothrombosis is associated with the presence of neovessels and pro-inflammatory macrophages expressing iNOS2. Modulating macrophage polarization may be a successful therapeutic approach to prevent plaque destabilization.

Multi-proteomic Biomarker Risk Scores for Predicting Risk and Guiding Therapy in Patients with Coronary Artery Disease

PURPOSE OF REVIEW

Patients with established coronary artery disease (CAD) are at high residual risk for adverse events, despite guideline-based treatments. Herein, we aimed to determine whether risk scores based on multiple circulating biomarkers that represent activation of various pathophysiologically important pathways involved in atherosclerosis and myocardial dysfunction help identify those at greatest residual risk.

RECENT FINDINGS

Numerous circulating proteins, representing dysregulation of the pathways involved in the development and stability of coronary and myocardial diseases, have been identified. When aggregated together, biomarker risk scores (BRS) more accurately stratify patients with established CAD that may help target interventions in those individuals who are at elevated risk. Moreover, intensification of guideline-based therapies has been associated with parallel improvements in both BRS and outcomes, indicating that these risk scores may be employed clinically to target therapy. Multi-protein BRS are predictive of risk, independent of, and in addition to traditional risk factor assessments in patients with CAD. Those with elevated risk may benefit from optimization of therapies, and improvements in the BRS will identify those with improved outcomes.

The microenvironment of the atheroma expresses phenotypes of plaque instability

Data from histopathology studies of human atherosclerotic tissue specimens and from vascular imaging studies support the concept that the local arterial microenvironment of a stable atheroma promotes destabilizing conditions that result in the transition to an unstable atheroma. Destabilization is characterized by several different plaque phenotypes that cause major clinical events such as acute coronary syndrome and cerebrovascular strokes. There are several rupture-associated phenotypes causing thrombotic vascular occlusion including simple fibrous cap rupture of an atheroma, fibrous cap rupture at site of previous rupture-and-repair of an atheroma, and nodular calcification with rupture. Endothelial erosion without rupture has more recently been shown to be a common phenotype to promote thrombosis as well. Microenvironment features that are linked to these phenotypes of plaque instability are neovascularization arising from the vasa vasorum network leading to necrotic core expansion, intraplaque hemorrhage, and cap rupture; activation of adventitial and perivascular adipose tissue cells leading to secretion of cytokines, growth factors, adipokines in the outer artery wall that destabilize plaque structure; and vascular smooth muscle cell phenotypic switching through transdifferentiation and stem/progenitor cell activation resulting in the promotion of inflammation, calcification, and secretion of extracellular matrix, altering fibrous cap structure, and necrotic core growth. As the technology evolves, studies using noninvasive vascular imaging will be able to investigate the transition of stable to unstable atheromas in real time. A limitation in the field, however, is that reliable and predictable experimental models of spontaneous plaque rupture and/or erosion are not currently available to study the cell and molecular mechanisms that regulate the conversion of the stable atheroma to an unstable plaque.

Effect of erythrophagocytosis-induced ferroptosis during angiogenesis in atherosclerotic plaques

Intraplaque (IP) angiogenesis is a key feature of advanced atherosclerotic plaques. Because IP vessels are fragile and leaky, erythrocytes are released and phagocytosed by macrophages (erythrophagocytosis), which leads to high intracellular iron content, lipid peroxidation and cell death. In vitro experiments showed that erythrophagocytosis by macrophages induced non-canonical ferroptosis, an emerging type of regulated necrosis that may contribute to plaque destabilization. Erythrophagocytosis-induced ferroptosis was accompanied by increased expression of heme-oxygenase 1 and ferritin, and could be blocked by co-treatment with third generation ferroptosis inhibitor UAMC-3203. Both heme-oxygenase 1 and ferritin were also expressed in erythrocyte-rich regions of carotid plaques from ApoE-/- Fbn1C1039G+/- mice, a model of advanced atherosclerosis with IP angiogenesis. The effect of UAMC-3203 (12.35 mg/kg/day) on atherosclerosis was evaluated in ApoE-/- Fbn1C1039G+/- mice fed a western-type diet (WD) for 12 weeks (n = 13 mice/group) or 20 weeks (n = 16-21 mice/group) to distinguish between plaques without and with established IP angiogenesis, respectively. A significant decrease in carotid plaque thickness was observed after 20 weeks WD (87 ± 19 μm vs. 166 ± 20 μm, p = 0.006), particularly in plaques with confirmed IP angiogenesis or hemorrhage (108 ± 35 μm vs. 322 ± 40 μm, p = 0.004). This effect was accompanied by decreased IP heme-oxygenase 1 and ferritin expression. UAMC-3203 did not affect carotid plaques after 12 weeks WD or plaques in the aorta, which typically do not develop IP angiogenesis. Altogether, erythrophagocytosis-induced ferroptosis during IP angiogenesis leads to larger atherosclerotic plaques, an effect that can be prevented by ferroptosis inhibitor UAMC-3203.

The accumulation of erythrocytes quantified and visualized by Glycophorin C in carotid atherosclerotic plaque reflects intraplaque hemorrhage and pre-procedural neurological symptoms

The accumulation of erythrocyte membranes within an atherosclerotic plaque may contribute to the deposition of free cholesterol and thereby the enlargement of the necrotic core. Erythrocyte membranes can be visualized and quantified in the plaque by immunostaining for the erythrocyte marker glycophorin C. Hence, we theorized that the accumulation of erythrocytes quantified by glycophorin C could function as a marker for plaque vulnerability, possibly reflecting intraplaque hemorrhage (IPH), and offering predictive value for pre-procedural neurological symptoms. We employed the CellProfiler-integrated slideToolKit workflow to visualize and quantify glycophorin C, defined as the total plaque area that is positive for glycophorin C, in single slides of culprit lesions obtained from the Athero-Express Biobank of 1819 consecutive asymptomatic and symptomatic patients who underwent carotid endarterectomy. Our assessment included the evaluation of various parameters such as lipid core, calcifications, collagen content, SMC content, and macrophage burden. These parameters were evaluated using a semi-quantitative scoring method, and the resulting data was dichotomized as predefined criteria into categories of no/minor or moderate/heavy staining. In addition, the presence or absence of IPH was also scored. The prevalence of IPH and pre-procedural neurological symptoms were 62.4% and 87.1%, respectively. The amount of glycophorin staining was significantly higher in samples from men compared to samples of women (median 7.15 (IQR:3.37, 13.41) versus median 4.06 (IQR:1.98, 8.32), p < 0.001). Glycophorin C was associated with IPH adjusted for clinical confounders (OR 1.90; 95% CI 1.63, 2.21; p =  < 0.001). Glycophorin C was significantly associated with ipsilateral pre-procedural neurological symptoms (OR:1.27, 95%CI:1.06-1.41, p = 0.005). Sex-stratified analysis, showed that this was also the case for men (OR 1.37; 95%CI 1.12, 1.69; p = 0.003), but not for women (OR 1.15; 95%CI 0.77, 1.73; p = 0.27). Glycophorin C was associated with classical features of a vulnerable plaque, such as a larger lipid core, a higher macrophage burden, less calcifications, a lower collagen and SMC content. There were marked sex differences, in men, glycophorin C was associated with calcifications and collagen while these associations were not found in women. To conclude, the accumulation of erythrocytes in atherosclerotic plaque quantified and visualized by glycophorin C was independently associated with the presence of IPH, preprocedural symptoms in men, and with a more vulnerable plaque composition in both men and women. These results strengthen the notion that the accumulation of erythrocytes quantified by glycophorin C can be used as a marker for plaque vulnerability.

Ferroptosis: A potential target of macrophages in plaque vulnerability

Plaque vulnerability has been the subject of several recent studies aimed at reducing the risk of stroke and carotid artery stenosis. Atherosclerotic plaque development is a complex process involving inflammation mediated by macrophages. Plaques become more vulnerable when the equilibrium between macrophage recruitment and clearance is disturbed. Lipoperoxides, which are affected by iron levels in cells, are responsible for the cell death seen in ferroptosis. Ferroptosis results from lipoperoxide-induced mitochondrial membrane toxicity. Atherosclerosis in ApoE(-/-) mice is reduced when ferroptosis is inhibited and iron intake is limited. Single-cell sequencing revealed that a ferroptosis-related gene was substantially expressed in atherosclerosis-modeled macrophages. Since ferroptosis can be regulated, it offers hope as a non-invasive method of treating carotid plaque. In this study, we discuss the role of ferroptosis in atherosclerotic plaque vulnerability, including its mechanism, regulation, and potential future research directions.

[68Ga]Ga-NODAGA-E[(cRGDyK)]2 angiogenesis PET following myocardial infarction in an experimental rat model predicts cardiac functional parameters and development of heart failure

BACKGROUND

Angiogenesis has increasingly been a target for imaging and treatment over the last decade. The integrin αvβ3 is highly expressed in cells during angiogenesis and are therefore a promising target for imaging. In this study, we aimed to investigate the PET tracer [68Ga]Ga-RGD as a marker of angiogenesis following MI and its ability to predict cardiac functional parameters.

METHODS

First, the real-time interaction between [68Ga]Ga-RGD and integrin αvβ3 was investigated using surface plasmon resonance (SPR). Second, an animal study was performed to investigate the [68Ga]Ga-RGD uptake in the infarcted area after one and four weeks following MI in a rat model (MI = 68, sham surgery = 36). Finally, the specificity of the [68Ga]Ga-RGD tracer was evaluated ex vivo using histology, autoradiography, gamma counting and flow cytometry.

RESULTS

SPR showed that [68Ga]Ga-RGD has a high affinity for integrin αvβ3, forming a strong and stable binding. PET/CT showed a significantly higher uptake of [68Ga]Ga-RGD in the infarcted area compared to sham one week (p < 0.001) and four weeks (p < 0.001) after MI. The uptake of [68Ga]Ga-RGD after one week correlated to end diastolic volume (r = 0.74, p < 0.001) and ejection fraction (r = - 0.71, p < 0.001) after four weeks.

CONCLUSION

This study demonstrates that [68Ga]Ga-RGD has a high affinity for integrin αvβ3, which enables the evaluation of angiogenesis and remodeling. The [68Ga]Ga-RGD uptake after one week indicates that [68Ga]Ga-RGD may be used as an early predictor of cardiac functional parameters and possible development of heart failure after MI. These encouraging data supports the clinical translation and future use in MI patients.

Progression of Arterial Vasa Vasorum from Regulator of Arterial Homeostasis to Promoter of Atherogenesis

The vasa vasorum (vessels of vessels) are a dynamic microvascular system uniquely distributed to maintain physiological homeostasis of the artery wall by supplying nutrients and oxygen to the outer layers of the artery wall, adventitia, and perivascular adipose tissue, and in large arteries, to the outer portion of the medial layer. Vasa vasorum endothelium and contractile mural cells regulate direct access of bioactive cells and factors present in both the systemic circulation and the arterial perivascular adipose tissue and adventitia to the artery wall. Experimental and human data show that proatherogenic factors and cells gain direct access to the artery wall via the vasa vasorum and may initiate, promote, and destabilize the plaque. Activation and growth of vasa vasorum occur in all blood vessel layers primarily by angiogenesis, producing fragile and permeable new microvessels that may cause plaque hemorrhage and fibrous cap rupture. Ironically, invasive therapies, such as angioplasty and coronary artery bypass grafting, injure the vasa vasorum, leading to treatment failures. The vasa vasorum function both as a master integrator of arterial homeostasis and, once perturbed or injured, as a promotor of atherogenesis. Future studies need to be directed at establishing reliable in vivo and in vitro models to investigate the cellular and molecular regulation of the function and dysfunction of the arterial vasa vasorum.

Predictors of Inappropriately Rapid Coronary Lesion Progression in Patients Undergoing Percutaneous Coronary Interventions

Background

Patients undergoing percutaneous coronary intervention (PCI) may experience rapid atherosclerotic plaque progression in nontreated vessels that is unlikely to result from natural de novo atherosclerosis. We hypothesize that intra-lesion bleeding plays a central role in this process. The aim of this study is to investigate the factors that may contribute to accelerated narrowing in coronary diameter.

Methods

We reviewed 65 interventional procedures and their consequent staged PCIs and mapped the coronary tree into 16 segments (as divided by the American Heart Association), grading the percentage of stenosis in each segment and spotting the rapidly progressing lesions. Demographic, procedural, and laboratory data were recorded and analyzed.

Results

For the lesions that progressed rapidly in the time period between angiographies, the administration of eptifibatide intra-procedurally was associated with rapid progression of coronary lesions. Moreover, an increased white blood cell count prior to the index procedure was also associated with a trend toward rapid plaque progression.

Conclusions

In this hypothesis-generating study, treatment with a IIb/IIIa inhibitor in the index PCI was associated with an accelerated short-term progression of some of the nontreated lesions, suggesting that this mode of anti-aggregation therapy could facilitate plaque hemorrhage and consequent acceleration of coronary atherosclerosis in eroded plaques.

Significance of Intra-plaque Hemorrhage for the Development of High-Risk Vulnerable Plaque: Current Understanding from Basic to Clinical Points of View

Acute coronary syndromes due to atherosclerotic coronary artery disease are a leading cause of morbidity and mortality worldwide. Intra-plaque hemorrhage (IPH), caused by disruption of intra-plaque leaky microvessels, is one of the major contributors of plaque progression, causing a sudden increase in plaque volume and eventually plaque destabilization. IPH and its healing processes are highly complex biological events that involve interactions between multiple types of cells in the plaque, including erythrocyte, macrophages, vascular endothelial cells and vascular smooth muscle cells. Recent investigations have unveiled detailed molecular mechanisms by which IPH leads the development of high-risk "vulnerable" plaque. Current advances in clinical diagnostic imaging modalities, such as magnetic resonance image and intra-coronary optical coherence tomography, increasingly allow us to identify IPH in vivo. To date, retrospective and prospective clinical trials have revealed the significance of IPH as detected by various imaging modalities as a reliable prognostic indicator of high-risk plaque. In this review article, we discuss recent advances in our understanding for the significance of IPH on the development of high-risk plaque from basic to clinical points of view.

Pharmacological Prevention of Ectopic Erythrophagocytosis by Cilostazol Mitigates Ferroptosis in NASH

Hepatic iron overload (HIO) is a hallmark of nonalcoholic fatty liver disease (NAFLD) with a poor prognosis. Recently, the role of hepatic erythrophagocytosis in NAFLD is emerging as a cause of HIO. We undertook various assays using human NAFLD patient pathology samples and an in vivo nonalcoholic steatohepatitis (NASH) mouse model named STAMTM. To make the in vitro conditions comparable to those of the in vivo NASH model, red blood cells (RBCs) and platelets were suspended and subjected to metabolic and inflammatory stresses. An insert-coculture system, in which activated THP-1 cells and RBCs are separated from HepG2 cells by a porous membrane, was also employed. Through various analyses in this study, the effect of cilostazol was examined. The NAFLD activity score, including steatosis, ballooning degeneration, inflammation, and fibrosis, was increased in STAMTM mice. Importantly, hemolysis occurred in the serum of STAMTM mice. Although cilostazol did not improve lipid or glucose profiles, it ameliorated hepatic steatosis and inflammation in STAMTM mice. Platelets (PLTs) played an important role in increasing erythrophagocytosis in the NASH liver. Upregulated erythrophagocytosis drives cells into ferroptosis, resulting in liver cell death. Cilostazol inhibited the augmentation of PLT and RBC accumulation. Cilostazol prevented the PLT-induced increase in ectopic erythrophagocytosis in in vivo and in vitro NASH models. Cilostazol attenuated ferroptosis of hepatocytes and phagocytosis of RBCs by THP-1 cells. Augmentation of hepatic erythrophagocytosis by activated platelets in NASH exacerbates HIO. Cilostazol prevents ectopic erythrophagocytosis, mitigating HIO-mediated ferroptosis in NASH models.

Validating human and mouse tissues commonly used in atherosclerosis research with coronary and aortic reference tissue: similarities but profound differences in disease initiation and plaque stability

Objective

Characterization of the atherosclerotic process fully relies on histological evaluation and staging through a consensus grading system. So far, a head-to-head comparison of atherosclerotic process in experimental models and tissue resources commonly applied in atherosclerosis research with the actual human atherosclerotic process is missing.

Material and Methods

Aspects of the atherosclerotic process present in established murine atherosclerosis models and human carotid endarterectomy specimen were systematically graded using the modified American Heart Association histological classification (Virmani classification). Aspects were aligned with the atherosclerotic process observed in human coronary artery and aortic atherosclerosis reference tissues that were available through biobanks based on human tissue/organ donor material.

Results

Apart from absent intraplaque hemorrhages in aortic lesions, the histological characteristics of the different stages of human coronary and aortic atherosclerosis are similar. Carotid endarterectomy samples all represent end-stage "fibrous calcified plaque" lesions, although secondary, progressive, and vulnerable lesions with gross morphologies similar to coronary/aortic lesions occasionally present along the primary lesions. For the murine lesions, clear histological parallels were observed for the intermediate lesion types ("pathological intimal thickening," and "early fibroatheroma"). However, none of the murine lesions studied progressed to an equivalent of late fibroatheroma or beyond. Notable contrasts were observed for disease initiation: whereas disease initiation in humans is characterized by a mesenchymal cell influx in the intima, the earliest murine lesions are exclusively intimal, with subendothelial accumulation foam cells. A mesenchymal (and medial) response are absent. In fact, it is concluded that the stage of "adaptive intimal thickening" is absent in all mouse models included in this study.

Conclusions

The Virmani classification for coronary atherosclerosis can be applied for systematically grading experimental and clinical atherosclerosis. Application of this histological grading tool shows clear parallels for intermediate human and murine atherosclerotic lesions. However, clear contrasts are observed for disease initiation, and late stage atherosclerotic lesions. Carotid endarterectomy all represent end-stage fibrous calcified plaque lesions, although secondary earlier lesions may present in a subset of samples.

Spatial Transcriptional Mapping Reveals Site-Specific Pathways Underlying Human Atherosclerotic Plaque Rupture

BACKGROUND

Atherosclerotic plaque ruptures, triggered by blood flow-associated biomechanical forces, cause most myocardial infarctions and strokes.

OBJECTIVES

This study aims to investigate the exact location and underlying mechanisms of atherosclerotic plaque ruptures, identifying therapeutic targets against cardiovascular events.

METHODS

Histology, electron microscopy, bulk and spatial RNA sequencing on human carotid plaques were studied in proximal, most stenotic, and distal regions along the longitudinal blood flow direction. Genome-wide association studies were used to examine heritability enrichment and causal relationships of atherosclerosis and stroke. Associations between top differentially expressed genes (DEGs) and preoperative and postoperative cardiovascular events were examined in a validation cohort.

RESULTS

In human carotid atherosclerotic plaques, ruptures predominantly occurred in the proximal and most stenotic regions but not in the distal region. Histologic and electron microscopic examination showed that proximal and most stenotic regions exhibited features of plaque vulnerability and thrombosis. RNA sequencing identified DEGs distinguishing the proximal and most stenotic regions from the distal region which were deemed as most relevant to atherosclerosis-associated diseases as shown by heritability enrichment analyses. The identified pathways associated with the proximal rupture-prone regions were validated by spatial transcriptomics, firstly in human atherosclerosis. Of the 3 top DEGs, matrix metallopeptidase 9 emerged particularly because Mendelian randomization suggested that its high circulating levels were causally associated with atherosclerosis risk.

CONCLUSIONS

Our findings show plaque site-specific transcriptional signatures associated with proximal rupture-prone regions of carotid atherosclerotic plaques. This led to the geographical mapping of novel therapeutic targets, such as matrix metallopeptidase 9, against plaque rupture.

Dietary Iron Restriction Protects against Aneurysm Rupture in a Mouse Model of Intracranial Aneurysm

INTRODUCTION

Iron accumulation in vessel walls induces oxidative stress and inflammation, which can cause cerebrovascular damage, vascular wall degeneration, and intracranial aneurysmal formation, growth, and rupture. Subarachnoid hemorrhage from intracranial aneurysm rupture results in significant morbidity and mortality. This study used a mouse model of intracranial aneurysm to evaluate the effect of dietary iron restriction on aneurysm formation and rupture.

METHODS

Intracranial aneurysms were induced using deoxycorticosterone acetate-salt-induced hypertension and a single injection of elastase into the cerebrospinal fluid of the basal cistern. Mice were fed an iron-restricted diet (n = 23) or a normal diet (n = 25). Aneurysm rupture was detected by neurological symptoms, while the presence of intracranial aneurysm with subarachnoid hemorrhage was confirmed by post-mortem examination.

RESULTS

The aneurysmal rupture rate was significantly lower in iron-restricted diet mice (37%) compared with normal diet mice (76%; p < 0.05). Serum oxidative stress, iron accumulation, macrophage infiltration, and 8-hydroxy-2'-deoxyguanosine in the vascular wall were lower in iron-restricted diet mice (p < 0.01). The areas of iron positivity were similar to the areas of CD68 positivity and 8-hydroxy-2'-deoxyguanosine in both normal diet and iron-restricted diet mouse aneurysms.

CONCLUSIONS

These findings suggest that iron is involved in intracranial aneurysm rupture via vascular inflammation and oxidative stress. Dietary iron restriction may have a promising role in preventing intracranial aneurysm rupture.

SR-B1-/-ApoE-R61h/h Mice Mimic Human Coronary Heart Disease

Cardiovascular diseases are the leading cause of death in the modern world. Atherosclerosis underlies the majority of these pathologies and may result in sudden life-threatening events such as myocardial infarction or stroke. Current concepts consider a rupture (resp. erosion) of "unstable/vulnerable" atherosclerotic plaques as a primary cause leading to thrombus formation and subsequent occlusion of the artery lumen finally triggering an acute clinical event. We and others described SR-B1-/-ApoE-R61h/h mice mimicking clinical coronary heart disease in all major aspects: from coronary atherosclerosis through vulnerable plaque ruptures leading to thrombus formation/coronary artery occlusion, finally resulting in myocardial infarction/ischemia. SR-B1-/-ApoE-R61h/h mouse provides a valuable model to study vulnerable/occlusive plaques, to evaluate bioactive compounds as well as new anti-inflammatory and "anti-rupture" drugs, and to test new technologies in experimental cardiovascular medicine. This review summarizes and discuss our knowledge about SR-B1-/-ApoE-R61h/h mouse model based on recent publications and experimental observations from the lab.

Acute Coronary Syndrome: Disparities of Pathophysiology and Mortality with and without Peripheral Artery Disease

There are a number of devastating complications associated with peripheral artery disease, including limb amputations and acute limb ischemia. Despite the overlap, atherosclerotic diseases have distinct causes that need to be differentiated and managed appropriately. In coronary atherosclerosis, thrombosis is often precipitated by rupture or erosion of fibrous caps around atheromatous plaques, which leads to acute coronary syndrome. Regardless of the extent of atherosclerosis, peripheral artery disease manifests itself as thrombosis. Two-thirds of patients with acute limb ischemia have thrombi associated with insignificant atherosclerosis. A local thrombogenic or remotely embolic basis of critical limb ischemia may be explained by obliterative thrombi in peripheral arteries of patients without coronary artery-like lesions. Studies showed that thrombosis of the above-knee arteries was more commonly due to calcified nodules, which are the least common cause of luminal thrombosis associated with acute coronary events in patients with acute coronary syndrome. Cardiovascular mortality was higher in peripheral artery disease without myocardial infarction/stroke than in myocardial infarction/stroke without peripheral artery disease. The aim of this paper is to gather published data regarding the disparities of acute coronary syndrome with and without peripheral artery disease in terms of pathophysiology and mortality.

Natural products targeting inflammation-related metabolic disorders: A comprehensive review

Currently, the incidence of metabolic disorders is increasing, setting a challenge to global health. With major advancement in the diagnostic tools and clinical procedures, much has been known in the etiology of metabolic disorders and their corresponding pathophysiologies. In addition, the use of in vitro and in vivo experimental models prior to clinical studies has promoted numerous biomedical breakthroughs, including in the discovery and development of drug candidates to treat metabolic disorders. Indeed, chemicals isolated from natural products have been extensively studied as prospective drug candidates to manage diabetes, obesity, heart-related diseases, and cancer, partly due to their antioxidant and anti-inflammatory properties. Continuous efforts have been made in parallel to improve their bioactivity and bioavailability using selected drug delivery approaches. Here, we provide insights on recent progress in the role of inflammatory-mediated responses on the initiation of metabolic disorders, with particular reference to diabetes mellitus, obesity, heart-related diseases, and cancer. In addition, we discussed the prospective role of natural products in the management of diabetes, obesity, heart-related diseases, and cancers and provide lists of potential biological targets for high throughput screening in drug discovery and development. Lastly, we discussed findings observed in the preclinical and clinical studies prior to identifying suitable approaches on the phytochemical drug delivery systems that are potential to be used in the treatment of metabolic disorders.

Patients with Carotid Intraplaque Hemorrhage Have Higher Incidence of Cerebral Microbleeds

AIMS

Carotid intraplaque hemorrhage (IPH) is considered a marker of plaque vulnerability. Cerebral microbleeds (CMBs) are recognized on magnetic resonance imaging (MRI) in patients with cerebrovascular disease. Any connection between carotid IPH and CMBs remains scantly investigated. This study aimed to determine whether the histologic evidence of carotid IPH is related to CMBs.

METHODS

We retrospectively enrolled 101 consecutive patients undergoing carotid endarterectomy with symptomatic (ischemic stroke, TIA, and amaurosis fugax) or asymptomatic ipsilateral carotid artery disease. The presence and the extent (%) of IPH were identified on carotid plaques stained with Movat Pentachrome. CMBs were localized on T2*-weighted gradient-recalled echo or susceptibility-weighted imaging sequence on brain MRI before surgery. The degree of carotid stenosis was measured by neck CTA.

RESULTS

IPH was identified in 57 (56.4%) patients, and CMBs were found in 24 (23.7%) patients. CMBs were more commonly observed in patients with carotid IPH compared to those without [19 (33.3%) vs 5 (11.4%); p=0.010]. The carotid IPH extent was significantly higher in patients with CMBs than in those without [9.0 % (2.8-27.1%) vs 0.9% (0.0-13.9%); p=0.004] and was associated with the number of CMBs (p=0.004). Logistic regression analysis demonstrated an independent association between carotid IPH extent and the presence of CMBs [OR 1.051 (95% CI 1.012-1.090); p=0.009]. Additionally, patients with CMBs had a lower degree of ipsilateral carotid stenosis compared to those without [40% (35-65%) vs 70% (50-80%); p=0.049].

CONCLUSIONS

CMBs may be potential markers of the ongoing process of carotid IPH, especially in those with nonobstructive plaques.

Intraplaque hemorrhage on magnetic resonance angiography: How often do signal abnormalities persist on follow-up imaging?

BACKGROUND AND PURPOSE

Intraplaque hemorrhage (IPH) in carotid atherosclerosis demonstrates increased signal on magnetic resonance angiography images. Little remains known about how this signal changes on subsequent examinations.

MATERIALS AND METHODS

A retrospective observational study was completed of patients that had IPH on a neck MRA between 1/1/2016 and 3/25/2021, defined as ≥ 200 % signal intensity of the sternocleidomastoid muscle on MPRAGE images. Examinations were excluded if the patients had undergone carotid endarterectomy between examinations or had poor quality imaging. IPH volumes were calculated by manually outlining IPH components. Up to 2 subsequent MRAs, if available, were assessed for both the presence and volume of IPH.

RESULTS

102 patients were included, of which 90 (86.5 %) were male. IPH was on the right in 48 patients (average volume = 174.0 mm³), and on the left in 70 patients (average volume 186.9 mm³). 22 had at least one follow-up (average 444.7 days between exams), and 6 had two follow-up MRAs (average 489.5 days between exams). On the first follow-up, 19 (86.4 %) plaques had persistent hyperintense signal in the region of IPH. The second follow-up showed persistent signal in 5/6 plaques (88.3 %). Combined volume of IPH from right and left carotid arteries did not significantly decrease on the first follow-up exam (p = 0.08).

CONCLUSIONS

IPH usually retains hyperintense signal on follow-up MRAs, possibly representing recurrent hemorrhage or degraded blood products.

Not All Quiet on the Atherosclerosis Front

In recent decades, research has identified the key cellular processes that take place during atherosclerotic plaque development and progression, including endothelial dysfunction, inflammation and lipoprotein oxidation, which result in macrophage and mural cell activation, death and necrotic core formation [...].

The Role of High-Resolution Magnetic Resonance Imaging in Cerebrovascular Disease: A Narrative Review

High-resolution magnetic resonance imaging (HRMRI) is the most important and popular vessel wall imaging technique for the direct assessment of vessel wall and cerebral arterial disease. It can identify the cause of stroke in high-risk plaques and differentiate the diagnosis of head and carotid artery dissection, including inflammation, Moya Moya disease, cerebral aneurysm, vasospasm after subarachnoid hemorrhage, reversible cerebral vasoconstriction syndrome, blunt cerebrovascular injury, cerebral arteriovenous malformations, and other stenosis or occlusion conditions. Through noninvasive visualization of the vessel wall in vitro, quantified assessment of luminal stenosis and pathological features of the vessel wall can provide clinicians with further disease information. In this report, technical considerations of HRMRI are discussed, and current clinical applications of HRMRI are reviewed.

Intravascular Ultrasound in Vulnerable Plaque and Acute Coronary Syndrome

Vulnerable plaque plays a pivotal role in the pathogenesis of acute coronary syndrome (ACS), being responsible for most ACS. The concept of vulnerable plaque has evolved with advancements in basic and clinical investigations along with developments and rapid expansion of coronary imaging modalities. Intravascular ultrasound (IVUS) is the first widely applied clinical technology with sufficient tissue penetration and enables us to identify vulnerable plaque and comprehensively understand the pathophysiology of ACS. In this review, we summarize current clinical evidence established by IVUS and the recent advancements in our understanding of vulnerable plaque and its role in ACS management.

Injury to the tunica media initiates atherogenesis in the presence of hyperlipidemia

Background and aims

Fatty streaks initiating the formation of atheromatous plaque appear in the tunica intima. The tunica media is not known to be a nidus for lipid accumulation initiating atherogenesis. We assessed changes to the tunica media in response to a micro-injury produced in the pig aorta. In addition, we assessed human carotid endarterectomy plaques for indication of atheroma initiation in the tunica media.

Methods

Three healthy landrace female pigs underwent laparotomy to inject autologous blood and create micro-hematomas at 6 sites within the tunica media of the infrarenal abdominal aorta. These pigs were fed a high-fat diet (HFD) for 4-12 weeks. Post-mortem aortas from all pigs, including a control group of healthy pigs, were serially stained to detect lipid deposits, vasa vasora (VV), immune cell infiltration and inflammatory markers, as well as changes to the vascular smooth muscle cell (vSMC) compartment. Moreover, 25 human carotid endarterectomy (CEA) specimens were evaluated for their lipid composition in the tunica media and intima.

Results

High lipid clusters, VV density, and immune cell infiltrates were consistently observed at 5 out of 6 injection sites under prolonged hyperlipidemia. The hyperlipidemic diet also affected the vSMC compartment in the tunica media adjacent to the tunica adventitia, which correlated with VV invasion and immune cell infiltration. Analysis of human carotid specimens post-CEA indicated that 32% of patients had significantly greater atheroma in the tunica media than in the arterial intima.

Conclusion

The arterial intima is not the only site for atherosclerosis initiation. We show that injury to the media can trigger atherogenesis.

Comprehensive analysis of atherosclerotic plaques reveals crucial genes and molecular mechanisms associated with plaque progression and rupture

Background

Plaque rupture and acute atherothrombosis, resulting from continued progression of atherosclerotic plaques (APs), are major contributors to acute clinical events such as stroke or myocardial infarction. This article aimed to explore the gene signatures and potential molecular mechanisms in the progression and instability of APs and to identify novel biomarkers and interventional targets for AP rupture.

Methods

The microarray data were downloaded from the Gene Expression Omnibus (GEO) database and grouped into discovery and validation cohorts. In the discovery cohort, Weighted Gene Co-Expression Network Analysis was performed for finding co-expression modules, and the Metascape database was used to perform functional enrichment analysis. Differential Expression Genes analysis subsequently was performed in the validation cohort for verification of the obtained results. Common genes were introduced into Metascape database for protein–protein interaction and functional enrichment analysis. We constructed the miRNAs–mRNAs network with the hub genes. Moreover, gene expression profiles of peripheral blood mononuclear cells (PBMCs) from peripheral blood of patients with plaque rupture were analyzed by high-throughput sequencing, and the diagnostic power of hub genes was verified by receiver operating characteristic (ROC) analysis.

Results

In the discovery cohort, the brown module in GSE28829 and the turquoise module in GSE163154 were the most significant co-expression modules. Functional enrichment analysis of shared genes suggested that “Neutrophil degranulation” was the most significantly enriched pathway. These conclusions were also demonstrated by the validation cohort. A total of 16 hub genes were identified. The miRNA–mRNA network revealed that hsa-miR-665 and hsa-miR-512-3p might regulate the “Neutrophil degranulation” pathway through PLAU and SIRPA, which might play a significant role in AP progression and instability. Five hub genes, including PLAUR, FCER1G, PLAU, ITGB2, and SLC2A5, showed significantly increased expression in PBMCs from patients with plaque rupture compared with controls. ROC analysis finally identified three hub genes PLAUR, FCER1G, and PLAU that could effectively distinguish patients with APs rupture from controls.

Conclusions

The present study demonstrated that the “neutrophil degranulation” signaling pathways and identified novel mRNA and miRNA candidates are closely associated with plaque progression and instability. The hub genes FCER1G, PLAUR, and PLAU may serve as biomarkers for the prospective prediction of AP rupture.

Sensitive magnetic particle imaging of haemoglobin degradation for the detection and monitoring of intraplaque haemorrhage in atherosclerosis

BACKGROUND

Intraplaque haemorrhage (IPH) drives atherosclerosis progression and is a key imaging biomarker of unstable plaques. Non-invasive and sensitive monitoring of IPH is challenging due to the compositional complexity and dynamic nature of atherosclerotic plaques. Magnetic particle imaging (MPI) is a highly sensitive, radiation-free, and no-tissue-background tomographic technique that detects superparamagnetic nanoparticles. Thus, we aimed to investigate whether MPI can in vivo detect and monitor IPH.

METHODS

Thirty human carotid endarterectomy samples were collected and scanned with MPI. The tandem stenosis (TS) model was employed to establish unstable plaques with IPH in ApoE^-/- mice. MPI and 7 T T1-weighted magnetic resonance imaging (MRI) were performed on TS ApoE^-/- mice. Plaque specimens were analyzed histologically.

FINDINGS

Human carotid endarterectomy samples exhibited endogenous MPI signals, which histologically colocalized with IPH. In vitro experiments identified haemosiderin, a haemoglobin degradation product, as a potential source of MPI signals. Longitudinal MPI of TS ApoE^-/- mice detected IPH at unstable plaques, of which MPI signal-to-noise ratio values increased from 6.43 ± 1.74 (four weeks) to 10.55 ± 2.30 (seven weeks) and reduced to 7.23 ± 1.44 (eleven weeks). In contrast, 7 T T1-weighted MRI did not detect the small-size IPH (329.91 ± 226.82 μm²) at four weeks post-TS. The time-course changes in IPH were shown to correlate with neovessel permeability providing a possible mechanism for signal changes over time.

INTERPRETATION

MPI is a highly sensitive imaging technology that allows the identification of atherosclerotic plaques with IPH and may help detect and monitor unstable plaques in patients.

FUNDING

This work was supported in part by the Beijing Natural Science Foundation under Grant JQ22023; the National Key Research and Development Program of China under Grant 2017YFA0700401; the National Natural Science Foundation of China under Grant 62027901, 81827808, 81730050, 81870178, 81800221, 81527805, and 81671851; the CAS Youth Innovation Promotion Association under Grant Y2022055 and CAS Key Technology Talent Program; and the Project of High-Level Talents Team Introduction in Zhuhai City (Zhuhai HLHPTP201703).

CD163+ macrophages restrain vascular calcification, promoting the development of high-risk plaque

Vascular calcification (VC) is concomitant with atherosclerosis, yet it remains uncertain why rupture-prone high-risk plaques do not typically show extensive calcification. Intraplaque hemorrhage (IPH) deposits erythrocyte-derived cholesterol, enlarging the necrotic core and promoting high-risk plaque development. Pro-atherogenic CD163+ alternative macrophages engulf hemoglobin:haptoglobin (HH) complexes at IPH sites. However, their role in VC has never been examined to our knowledge. Here we show, in human arteries, the distribution of CD163+ macrophages correlated inversely with VC. In vitro experiments using vascular smooth muscle cells (VSMCs) cultured with HH-exposed human macrophage - M(Hb) - supernatant reduced calcification, while arteries from ApoE-/- CD163-/- mice showed greater VC. M(Hb) supernatant-exposed VSMCs showed activated NF-κB, while blocking NF-κB attenuated the anticalcific effect of M(Hb) on VSMCs. CD163+ macrophages altered VC through NF-κB-induced transcription of hyaluronan synthase (HAS), an enzyme that catalyzes the formation of the extracellular matrix glycosaminoglycan, hyaluronan, within VSMCs. M(Hb) supernatants enhanced HAS production in VSMCs, while knocking down HAS attenuated its anticalcific effect. NF-κB blockade in ApoE-/- mice reduced hyaluronan and increased VC. In human arteries, hyaluronan and HAS were increased in areas of CD163+ macrophage presence. Our findings highlight an important mechanism by which CD163+ macrophages inhibit VC through NF-κB-induced HAS augmentation and thus promote the high-risk plaque development.

Intracoronary Imaging of Coronary Atherosclerotic Plaque: From Assessment of Pathophysiological Mechanisms to Therapeutic Implication

Atherosclerotic cardiovascular disease is the leading cause of morbidity and mortality worldwide. Several cardiovascular risk factors are implicated in atherosclerotic plaque promotion and progression and are responsible for the clinical manifestations of coronary artery disease (CAD), ranging from chronic to acute coronary syndromes and sudden coronary death. The advent of intravascular imaging (IVI), including intravascular ultrasound, optical coherence tomography and near-infrared diffuse reflectance spectroscopy has significantly improved the comprehension of CAD pathophysiology and has strengthened the prognostic relevance of coronary plaque morphology assessment. Indeed, several atherosclerotic plaque phenotype and mechanisms of plaque destabilization have been recognized with different natural history and prognosis. Finally, IVI demonstrated benefits of secondary prevention therapies, such as lipid-lowering and anti-inflammatory agents. The purpose of this review is to shed light on the principles and properties of available IVI modalities along with their prognostic significance.

Current Toolset in Predicting Acute Coronary Thrombotic Events: The “Vulnerable Plaque” in a “Vulnerable Patient” Concept

Despite major advances in pharmacotherapy and interventional procedures, coronary artery disease (CAD) remains a principal cause of morbidity and mortality worldwide. Invasive coronary imaging along with the computation of hemodynamic forces, primarily endothelial shear stress and plaque structural stress, have enabled a comprehensive identification of atherosclerotic plaque components, providing a unique insight into the understanding of plaque vulnerability and progression, which may help guide patient treatment. However, the invasive-only approach to CAD has failed to show high predictive value. Meanwhile, it is becoming increasingly evident that along with the “vulnerable plaque”, the presence of a “vulnerable patient” state is also necessary to precipitate an acute coronary thrombotic event. Non-invasive imaging techniques have also evolved, providing new opportunities for the identification of high-risk plaques, the study of atherosclerosis in asymptomatic individuals, and general population screening. Additionally, risk stratification scores, circulating biomarkers, immunology, and genetics also complete the armamentarium of a broader “vulnerable plaque and patient” concept approach. In the current review article, the invasive and non-invasive modalities used for the detection of high-risk plaques in patients with CAD are summarized and critically appraised. The challenges of the vulnerable plaque concept are also discussed, highlighting the need to shift towards a more interdisciplinary approach that can identify the “vulnerable plaque” in a “vulnerable patient”.

Potential miRNA biomarkers and therapeutic targets for early atherosclerotic lesions

Identification of potential therapeutic targets and biomarkers indicative of burden of early atherosclerosis that occur prior to advancement to life-threatening unstable plaques is the key to eradication of CAD prevalence and incidences. We challenged 16 baboons with a high cholesterol, high fat diet for 2 years and evaluated early-stage atherosclerotic lesions (fatty streaks, FS, and fibrous plaques, FP) in formalin-fixed common iliac arteries (CIA). We used small RNA sequencing to identify expressed miRNAs in CIA and in baseline blood samples of the same animals. We found 412 expressed miRNAs in CIA and 356 in blood samples. Eight miRNAs (miR-7975, -486-5p, -451a, -191-5p, -148a-3p, -17-5p, -378c, and -144-3p) were differentially expressed between paired fatty streak lesion and no-lesion sites of the tissue, and 27 miRNAs (e.g., miR-92a-3p, -5001, -342-3p, miR-28-3p, -21-5p, -221-3p, 146a-5p, and -16-5p) in fibrous plaques. The expression of 14 blood miRNAs significantly correlated with extent of lesions and the number of plaques. We identified coordinately regulated miRNA-gene networks in which miR-17-5p and miR-146a-5p are central hubs and miR-5001 and miR-7975 are potentially novel miRNAs associated with early atherosclerosis. In summary, we have identified miRNAs expressed in lesions and in blood that correlate with lesion burden and are potential therapeutic targets and biomarkers. These findings are a first step in elucidating miRNA regulated molecular mechanisms that underlie early atherosclerosis in a baboon model, enabling translation of our findings to humans.

Vulnerable Plaque Imaging

Atherosclerotic plaques progress as a result of inflammation. Both invasive and noninvasive imaging techniques have been developed to identify and characterize plaque as vulnerable (more likely to rupture and cause a clinical event). Imaging techniques to identify vulnerable include identifying vessels with focal subendothelial collections of I) inflammatory cells; II) lipid/ fatty acid; III) local regions of hypoxia; IV) local expression of angiogenesis factors; V) local expression of protease; VI) intravascular foci of thrombus; hemorrhage (most often seen in the aftermath of a clinical event); VII) apoptosis and VIII) microcalcification. This review provides an overview of atherosclerotic plaque progression and tracers which can visualize specific molecules associated with vulnerability.

Relationship between red cell distribution width/albumin ratio and carotid plaque in different glucose metabolic states in patients with coronary heart disease: a RCSCD-TCM study in China

BACKGROUND

Red cell distribution width/albumin ratio (RAR) is thought to be associated with the prognosis of a variety of diseases, including diabetes and heart failure. To date, no studies have focused on the relationship between RAR and carotid plaque in patients with coronary heart disease (CHD).

METHODS

A total of 10,267 patients with CHD were divided according to RAR quartiles (Q1: RAR ≤ 2.960; Q2: 2.960 < RAR ≤ 3.185; Q3: 3.185 < RAR < 3.441; Q4: RAR ≥ 3.441). Logistic regression was used to analyze the relationship between RAR and carotid plaques in CHD patients. The relationship between RAR and carotid plaques in according to sex, age and glucose regulation state groups were also assessed.

RESULTS

Among the 10,267 participants, 75.43% had carotid plaques. After adjusting for confounding factors, RAR was found to be associated with carotid plaque formation (OR: 1.23; 95% CI 1.08-1.39). The risk of carotid plaque formation in the Q4 group was 1.24 times higher than that in the Q1 group. After multivariate adjustment, RAR was associated with the risk of carotid plaque in female (OR: 1.29; 95% CI 1.09-1.52). And the relationship between RAR and carotid plaques in patients younger than 60 years old (OR: 1.43; 95% CI 1.16-1.75) was stronger than that in those older than 60 years old (OR: 1.29; 95% CI 1.10-1.51). Under different glucose metabolism states, RAR had the highest correlation with the risk of carotid plaques in diabetes patients (OR: 1.28; 95% CI 1.04-1.58).

CONCLUSIONS

RAR was significantly related to carotid plaques in patients with CHD. In addition, the correlation between RAR and the incidence of carotid plaque in patients with CHD was higher in women and middle-aged and elderly patients. In patients with CHD and diabetes, the correlation between RAR and carotid plaque was higher.

Insulin-like growth factor 1 reduces coronary atherosclerosis in pigs with familial hypercholesterolemia

Although murine models of coronary atherosclerotic disease have been used extensively to determine mechanisms, limited new therapeutic options have emerged. Pigs with familial hypercholesterolemia (FH pigs) develop complex coronary atheromas that are almost identical to human lesions. We reported previously that insulin-like growth factor 1 (IGF-1) reduced aortic atherosclerosis and promoted features of stable plaque in a murine model. We administered human recombinant IGF-1 or saline (control) in atherosclerotic FH pigs for 6 months. IGF-1 decreased relative coronary atheroma in vivo (intravascular ultrasound) and reduced lesion cross-sectional area (postmortem histology). IGF-1 increased plaque's fibrous cap thickness, and reduced necrotic core, macrophage content, and cell apoptosis, consistent with promotion of a stable plaque phenotype. IGF-1 reduced circulating triglycerides, markers of systemic oxidative stress, and CXCL12 chemokine levels. We used spatial transcriptomics (ST) to identify global transcriptome changes in advanced plaque compartments and to obtain mechanistic insights into IGF-1 effects. ST analysis showed that IGF-1 suppressed FOS/FOSB factors and gene expression of MMP9 and CXCL14 in plaque macrophages, suggesting possible involvement of these molecules in IGF-1's effect on atherosclerosis. Thus, IGF-1 reduced coronary plaque burden and promoted features of stable plaque in a pig model, providing support for consideration of clinical trials.

A Comprehensive Review: Epidemiological strategies, Catheterization and Biomarkers used as a Bioweapon in Diagnosis and Management of Cardio Vascular Diseases

Coronary artery disease (CAD) is a serious health problem that causes a considerable number of mortality in a number of affluent nations throughout the world. The estimated death encountered in many developed countries includes including Pakistan, reached 111,367 and accounted for 9.87% of all deaths, despite the mortality rate being around 7.2 million deaths per year, or 12% of all estimated deaths accounted annually around the globe, with improved health systems. Atherosclerosis progressing causes the coronary arteries to become partially or completely blocked, which results in CAD. Additionally, smoking, diabetes mellitus, homocystinuria, hypertension, obesity, hyperlipidemia, and psychological stress are risk factors for CAD. The symptoms of CAD include angina which is described as a burning, pain or discomfort in the chest, nausea, weakness, shortness of breath, lightheadedness, and pain or discomfort in the arms or shoulders. Atherosclerosis and thrombosis are the two pathophysiological pathways most frequently involved in acute coronary syndrome (ACS). Asymptomatic plaque disruption, plaque bleeding, symptomatic coronary blockage, and myocardial infarction are the prognoses for CAD. In this review, we will focus on medicated therapy which is being employed for the relief of angina linked with CAD including antiplatelet medicines, nitrates, calcium antagonists, blockers, catheterization, and the frequency of recanalized infarct-related arteries in patients with acute anterior wall myocardial infarction (AWMI). Furthermore, we have also enlightened the importance of biomarkers that are helpful in the diagnosis and management of CAD.

Virtual pathology: Reaching higher standards for noninvasive CTA tissue characterization capability by using histology as a truth standard

AIMS

Despite advances in therapy, reduction in myocardial infarction or death remains elusive. Whereas computed tomography angiography (CTA) is increasingly appreciated, the analyses are often subjective or qualitative. Methods for specific tissue characterization using histopathologic correlates have recently been reported. We extend this here to demonstrate accurate discrimination between, and quantitation of, lipid-rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and fibrotic tissues.

METHODS

NCT02143102 collected 576 tissue samples with paired CTA. Cardiovascular pathologists annotated LRNC, IPH, and dense calcification (CALC) regions as a reference standard. Blinded to histology, CTA was analyzed using ElucidVivo (Elucid Bioimaging Inc., Boston, MA USA). Structure and tissue characteristics of atherosclerotic plaque from CTA, accounting for both the imaging acquisition process and the biology, accounting for differences in density distributions that result from the different cellular and molecular level milieu of the relevant tissue types.

RESULTS

LRNC was tested across a true range of 0-10 mm², with a difference of 0.15 mm² and a slope of 0.92. IPH was tested across a true range of 0-18 mm², with a difference from histology of 1.68 mm² and a slope of 0.95. CALC was tested across a range of 0-14 mm², with a difference of -0.06 mm² and a slope of 0.99. Matrix tissue (MATX) was tested across a range of 4-52 mm², with a difference of 0.02 mm² and a slope of 0.91.

CONCLUSION

LRNC, IPH, CALC, and MATX may be objectively quantified using histopathologic correlates automatically from CTA for use singly or in combination to optimize patient care. The availability of objectively validated quantitative markers that may be followed longitudinally may extend the clinical utility of CTA. Additionally, these measures contribute efficacy variables for developing novel drugs and clinical decision support tools for tailored therapeutics.