| 1. |
- Buckler, Andrew J., et al.
(författare)
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Patient-specific biomechanical analysis of atherosclerotic plaques enabled by histologically validated tissue characterization from computed tomography angiography : A case study
- 2022
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Ingår i: Journal of The Mechanical Behavior of Biomedical Materials. - : Elsevier BV. - 1751-6161 .- 1878-0180. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- Background: Rupture of unstable atherosclerotic plaques with a large lipid-rich necrotic core and a thin fibrous cap cause myocardial infarction and stroke. Yet it has not been possible to assess this for individual patients. Clinical guidelines still rely on use of luminal narrowing, a poor indicator but one that persists for lack of effective means to do better. We present a case study demonstrating the assessment of biomechanical indices pertaining to plaque rupture risk non-invasively for individual patients enabled by histologically validated tissue characterization. Methods: Routinely acquired clinical images of plaques were analyzed to characterize vascular wall tissues using software validated by histology (ElucidVivo, Elucid Bioimaging Inc.). Based on the tissue distribution, wall stress and strain were then calculated at spatial locations with varied fibrous cap thicknesses at diastolic, mean and systolic blood pressures. Results: The von Mises stress of 152 [131, 172] kPa and the equivalent strain of 0.10 [0.08, 0.12] were calculated where the fibrous cap thickness was smallest (560 mu m) (95% CI in brackets). The stress at this location was at a level predictive of plaque failure. Stress and strain at locations with larger cap thicknesses were calculated to be lower, demonstrating a clinically relevant range of risk levels. Conclusion: Patient specific tissue characterization can identify distributions of stress and strain in a clinically relevant range. This capability may be used to identify high-risk lesions and personalize treatment decisions for individual patients with cardiovascular disease and improve prevention of myocardial infarction and stroke.
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| 2. |
- Buckler, Andrew J., et al.
(författare)
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Virtual Transcriptomics Noninvasive Phenotyping of Atherosclerosis by Decoding Plaque Biology From Computed Tomography Angiography Imaging
- 2021
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - : Ovid Technologies (Wolters Kluwer Health). - 1079-5642 .- 1524-4636. ; 41:5, s. 1738-1750
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Therapeutic advancements in atherosclerotic cardiovascular disease have improved prevention of ischemic stroke and myocardial infarction, but diagnostic methods for atherosclerotic plaque phenotyping to aid individualized therapy are lacking. In this feasibility study, we aimed to elucidate plaque biology by decoding the molecular phenotype of plaques through analysis of computed-tomography angiography images, making a predictive model for plaque biology referred to as virtual transcriptomics. Approach and Results: We employed machine intelligence using paired computed-tomography angiography and transcriptomics from carotid endarterectomies of 40 patients undergoing stroke-preventive surgery for carotid stenosis. Computed tomography angiographies were analyzed with novel software for accurate characterization of plaque morphology and plaque transcriptomes obtained from microarrays, followed by mathematical modeling for prediction of molecular signatures. Four hundred fourteen coding and noncoding RNAs were robustly predicted using supervised models to estimate gene expression based on plaque morphology. Examples of predicted transcripts included ion transporters, cytokine receptors, and a number of microRNAs whereas pathway analyses demonstrated enrichment of several biological processes relevant for the pathophysiology of atherosclerosis and plaque instability. Finally, the ability of the models to predict plaque gene expression was demonstrated using computed tomography angiographies from 4 sequestered patients and comparisons with transcriptomes of corresponding lesions. Conclusions: The results of this pilot study show that atherosclerotic plaque phenotyping by image analysis of conventional computed-tomography angiography can elucidate the molecular signature of atherosclerotic lesions in a multiscale setting. The study holds promise for optimized personalized therapy in the prevention of myocardial infarction and ischemic stroke, which warrants further investigations in larger cohorts.
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| 3. |
- Karlöf, Eva, et al.
(författare)
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Correlation of computed tomography with carotid plaque transcriptomes associates calcification with lesion-stabilization
- 2019
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Ingår i: Atherosclerosis. - Stockholm : ELSEVIER IRELAND LTD. - 0021-9150 .- 1879-1484. ; 288, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Unstable carotid atherosclerosis causes stroke, but methods to identify patients and lesions at risk are lacking. We recently found enrichment of genes associated with calcification in carotid plaques from asymptomatic patients. Here, we hypothesized that calcification represents a stabilising feature of plaques and investigated how macro-calcification, as estimated by computed tomography (CT), correlates with gene expression profiles in lesions. Methods: Plaque calcification was measured in pre-operative CT angiographies. Plaques were sorted into high- and low-calcified, profiled with microarrays, followed by bioinformatic analyses. Immunohistochemistry and qPCR were performed to evaluate the findings in plaques and arteries with medial calcification from chronic kidney disease patients. Results: Smooth muscle cell (SMC) markers were upregulated in high-calcified plaques and calcified plaques from symptomatic patients, whereas macrophage markers were downregulated. The most enriched processes in high-calcified plaques were related to SMCs and extracellular matrix (ECM) organization, while inflammation, lipid transport and chemokine signaling were repressed. These findings were confirmed in arteries with high medial calcification. Proteoglycan 4 (PRG4) was identified as the most upregulated gene in association with plaque calcification and found in the ECM, SMA+ and CD68+/TRAP + cells. Conclusions: Macro-calcification in carotid lesions correlated with a transcriptional profile typical for stable plaques, with altered SMC phenotype and ECM composition and repressed inflammation. PRG4, previously not described in atherosclerosis, was enriched in the calcified ECM and localized to activated macrophages and smooth muscle-like cells. This study strengthens the notion that assessment of calcification may aid evaluation of plaque phenotype and stroke risk.
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| 4. |
- Röhl, Samuel, et al.
(författare)
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Transcriptomic profiling of experimental arterial injury reveals new mechanisms and temporal dynamics in vascular healing response
- 2020
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Ingår i: JVS-Vascular Science. - : Elsevier BV. - 2666-3503. ; 315, s. E14-E14
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Endovascular interventions cause arterial injury and induce a healing response to restore vessel wall homeostasis. Complications of defective or excessive healing are common and result in increased morbidity and repeated interventions. Experimental models of intimal hyperplasia are vital for understanding the vascular healing mechanisms and resolving the clinical problems of restenosis, vein graft stenosis, and dialysis access failure. Our aim was to systematically investigate the transcriptional, histologic, and systemic reaction to vascular injury during a prolonged time. Methods: Balloon injury of the left common carotid artery was performed in male rats. Animals (n = 69) were euthanized before or after injury, either directly or after 2 hours, 20 hours, 2 days, 5 days, 2 weeks, 6 weeks, and 12 weeks. Both injured and contralateral arteries were subjected to microarray profiling, followed by bioinformatic exploration, histologic characterization of the biopsy specimens, and plasma lipid analyses. Results: Immune activation and coagulation were key mechanisms in the early response, followed by cytokine release, tissue remodeling, and smooth muscle cell modulation several days after injury, with reacquisition of contractile features in later phases. Novel pathways related to clonal expansion, inflammatory transformation, and chondro-osteogenic differentiation were identified and immunolocalized to neointimal smooth muscle cells. Analysis of uninjured arteries revealed a systemic component of the reaction after local injury, underlined by altered endothelial signaling, changes in overall tissue bioenergy metabolism, and plasma high-density lipoprotein levels. Conclusions: We demonstrate that vascular injury induces dynamic transcriptional landscape and metabolic changes identifiable as early, intermediate, and late response phases, reaching homeostasis after several weeks. This study provides a temporal “roadmap” of vascular healing as a publicly available resource for the research community.
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