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Wang X, Shen Y, Shang M, Liu X, Munn LL. Endothelial mechanobiology in atherosclerosis. Cardiovasc Res 2023; 119:1656-1675. [PMID: 37163659 PMCID: PMC10325702 DOI: 10.1093/cvr/cvad076] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 02/11/2023] [Accepted: 02/21/2023] [Indexed: 05/12/2023] Open
Abstract
Cardiovascular disease (CVD) is a serious health challenge, causing more deaths worldwide than cancer. The vascular endothelium, which forms the inner lining of blood vessels, plays a central role in maintaining vascular integrity and homeostasis and is in direct contact with the blood flow. Research over the past century has shown that mechanical perturbations of the vascular wall contribute to the formation and progression of atherosclerosis. While the straight part of the artery is exposed to sustained laminar flow and physiological high shear stress, flow near branch points or in curved vessels can exhibit 'disturbed' flow. Clinical studies as well as carefully controlled in vitro analyses have confirmed that these regions of disturbed flow, which can include low shear stress, recirculation, oscillation, or lateral flow, are preferential sites of atherosclerotic lesion formation. Because of their critical role in blood flow homeostasis, vascular endothelial cells (ECs) have mechanosensory mechanisms that allow them to react rapidly to changes in mechanical forces, and to execute context-specific adaptive responses to modulate EC functions. This review summarizes the current understanding of endothelial mechanobiology, which can guide the identification of new therapeutic targets to slow or reverse the progression of atherosclerosis.
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Affiliation(s)
- Xiaoli Wang
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310020, China
| | - Yang Shen
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Min Shang
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310020, China
| | - Xiaoheng Liu
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, China
| | - Lance L Munn
- Steele Laboratories, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Rowland E, Bailey E, Weinberg P. Estimating Arterial Cyclic Strain from the Spacing of Endothelial Nuclei. EXPERIMENTAL MECHANICS 2021; 61:171-190. [PMID: 33510542 PMCID: PMC7116634 DOI: 10.1007/s11340-020-00655-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
BACKGROUND The non-uniform distribution of atherosclerosis within the arterial system is widely attributed to variation in haemodynamic wall shear stress. It may also depend on variation in pressure-induced stresses and strains within the arterial wall; these have been less widely investigated, at least in part because of a lack of suitable techniques. OBJECTIVES Here we show that local arterial strain can be determined from impressions left by endothelial cells on the surface of vascular corrosion casts made at different pressures, even though only one pressure can be examined in each vessel. The pattern of pits in the cast caused by protruding endothelial nuclei was subject to "retro-deformation" to identify the pattern that would have occurred in the absence of applied stresses. METHODS Retaining the nearest-neighbour pairs found under this condition, changes in nearest-neighbour vectors were calculated for the pattern seen in the cast, and the ratio of mean changes at different pressures determined. This approach removes errors in simple nearest-neighbour analyses caused by the nearest neighbour changing as deformation occurs. RESULTS The accuracy, precision and robustness of the approach were validated using simulations. The method was implemented using confocal microscopy of casts of the rabbit aorta made at systolic and diastolic pressures; results agreed well with the ratio of the macroscopic dimensions of the casts. CONCLUSIONS Applying the new technique to areas around arterial branches could support or refute the hypothesis that the development of atherosclerosis is influenced by mural strain, and the method may be applicable to other tissues.
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Affiliation(s)
- E.M. Rowland
- Department of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - E.L. Bailey
- Department of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - P.D. Weinberg
- Department of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
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Evans RJ, Lavin B, Phinikaridou A, Chooi KY, Mohri Z, Wong E, Boyle JJ, Krams R, Botnar R, Long NJ. Targeted Molecular Iron Oxide Contrast Agents for Imaging Atherosclerotic Plaque. Nanotheranostics 2020; 4:184-194. [PMID: 32637296 PMCID: PMC7332796 DOI: 10.7150/ntno.44712] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/06/2020] [Indexed: 02/03/2023] Open
Abstract
Overview: Cardiovascular disease remains a leading cause of death worldwide, with vulnerable plaque rupture the underlying cause of many heart attacks and strokes. Much research is focused on identifying an imaging biomarker to differentiate stable and vulnerable plaque. Magnetic Resonance Imaging (MRI) is a non-ionising and non-invasive imaging modality with excellent soft tissue contrast. However, MRI has relatively low sensitivity (micromolar) for contrast agent detection compared to nuclear imaging techniques. There is also an increasing emphasis on developing MRI probes that are not based on gadolinium chelates because of increasing concerns over associated systemic toxicity and deposits1. To address the sensitivity and safety concerns of gadolinium this project focused on the development of a high relaxivity probe based on superparamagnetic iron oxide nanoparticles for the imaging of atherosclerotic plaque with MRI. With development, this may facilitate differentiating stable and vulnerable plaque in vivo. Aim: To develop a range of MRI contrast agents based on superparamagnetic iron oxide nanoparticles (SPIONs), and test them in a murine model of advanced atherosclerosis. Methods: Nanoparticles of four core sizes were synthesised by thermal decomposition and coated with poly(maleicanhydride-alt-1-octadecene) (PMAO), poly(ethyleneimine) (PEI) or alendronate, then characterised for core size, hydrodynamic size, surface potential and relaxivity. On the basis of these results, one candidate was selected for further studies. In vivo studies using 10 nm PMAO-coated SPIONs were performed in ApoE-/- mice fed a western diet and instrumented with a perivascular cuff on the left carotid artery. Control ApoE-/- mice were fed a normal chow diet and were not instrumented. Mice were scanned on a 3T MR scanner (Philips Achieva) with the novel SPION contrast agent, and an elastin-targeted gadolinium agent that was shown previously to enable visualisation of plaque burden. Histological analysis was undertaken to confirm imaging findings through staining for macrophages, CX3CL1, elastin, tropoelastin, and iron. Results: The lead SPION agent consisted of a 10 nm iron oxide core with poly(maleicanhydride-alt-1-octadecene), (-36.21 mV, r2 18.806 mmol-1/s-1). The irregular faceting of the iron oxide core resulted in high relaxivity and the PMAO provided a foundation for further functionalisation on surface -COOH groups. The properties of the contrast agent, including the negative surface charge and hydrodynamic size, were designed to maximise circulation time and evade rapid clearance through the renal system or phagocytosis. In vitro testing showed that the SPION agent was non-toxic. In vivo results show that the novel contrast agent accumulates in similar vascular regions to a gadolinium-based contrast agent (Gd-ESMA) targeted to elastin, which accumulates in plaque. There was a significant difference in SPION signal between the instrumented and the contralateral non-instrumented vessels in diseased mice (p = 0.0411, student's t-test), and between the instrumented diseased vessel and control vessels (p = 0.0043, 0.0022, student's t-test). There was no significant difference between the uptake of either contrast agent between stable and vulnerable plaques (p = 0.3225, student's t-test). Histological verification was used to identify plaques, and Berlin Blue staining confirmed the presence of nanoparticle deposits within vulnerable plaques and co-localisation with macrophages. Conclusion: This work presents a new MRI contrast agent for atherosclerosis which uses an under-explored surface ligand, demonstrating promising properties for in vivo behaviour, is still in circulation 24 hours post-injection with limited liver uptake, and shows good accumulation in a murine plaque model.
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Affiliation(s)
- Rhiannon J Evans
- Department of Chemistry, MSRH Building, Imperial College London, White City Campus, 80 Wood Lane, White City, London, W12 0BZ, UK.,School of Biomedical Engineering and Imaging Science, St. Thomas's Hospital, King's College London, London, SE1 7EH, UK
| | - Begoña Lavin
- School of Biomedical Engineering and Imaging Science, St. Thomas's Hospital, King's College London, London, SE1 7EH, UK
| | - Alkystis Phinikaridou
- School of Biomedical Engineering and Imaging Science, St. Thomas's Hospital, King's College London, London, SE1 7EH, UK
| | - Kok Yean Chooi
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Zahra Mohri
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Eunice Wong
- Department of Chemistry, MSRH Building, Imperial College London, White City Campus, 80 Wood Lane, White City, London, W12 0BZ, UK.,National Heart and Lung Institute, ICTEM Building, Imperial College London, Hammersmith Campus, Du Cane Rd, London, W12 0NN, UK
| | - Joseph J Boyle
- National Heart and Lung Institute, ICTEM Building, Imperial College London, Hammersmith Campus, Du Cane Rd, London, W12 0NN, UK
| | - Rob Krams
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - René Botnar
- School of Biomedical Engineering and Imaging Science, St. Thomas's Hospital, King's College London, London, SE1 7EH, UK
| | - Nicholas J Long
- Department of Chemistry, MSRH Building, Imperial College London, White City Campus, 80 Wood Lane, White City, London, W12 0BZ, UK
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Disturbed flow induces a sustained, stochastic NF-κB activation which may support intracranial aneurysm growth in vivo. Sci Rep 2019; 9:4738. [PMID: 30894565 PMCID: PMC6426999 DOI: 10.1038/s41598-019-40959-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 02/26/2019] [Indexed: 02/03/2023] Open
Abstract
Intracranial aneurysms are associated with disturbed velocity patterns, and chronic inflammation, but the relevance for these findings are currently unknown. Here, we show that (disturbed) shear stress induced by vortices is a sufficient condition to activate the endothelial NF-kB pathway, possibly through a mechanism of mechanosensor de-activation. We provide evidence for this statement through in-vitro live cell imaging of NF-kB in HUVECs exposed to different flow conditions, stochastic modelling of flow induced NF-kB activation and induction of disturbed flow in mouse carotid arteries. Finally, CFD and immunofluorescence on human intracranial aneurysms showed a correlation similar to the mouse vessels, suggesting that disturbed shear stress may lead to sustained NF-kB activation thereby offering an explanation for the close association between disturbed flow and intracranial aneurysms.
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Xing R, De Wilde D, McCann G, Ridwan Y, Schrauwen JTC, van der Steen AFW, Gijsen FJH, Van der Heiden K. Contrast-enhanced micro-CT imaging in murine carotid arteries: a new protocol for computing wall shear stress. Biomed Eng Online 2016; 15:156. [PMID: 28155699 PMCID: PMC5259814 DOI: 10.1186/s12938-016-0270-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Wall shear stress (WSS) is involved in the pathophysiology of atherosclerosis. The correlation between WSS and atherosclerosis can be investigated over time using a WSS-manipulated atherosclerotic mouse model. To determine WSS in vivo, detailed 3D geometry of the vessel network is required. However, a protocol to reconstruct 3D murine vasculature using this animal model is lacking. In this project, we evaluated the adequacy of eXIA 160, a small animal contrast agent, for assessing murine vascular network on micro-CT. Also, a protocol was established for vessel geometry segmentation and WSS analysis. METHODS A tapering cast was placed around the right common carotid artery (RCCA) of ApoE-/- mice (n = 8). Contrast-enhanced micro-CT was performed using eXIA 160. An innovative local threshold-based segmentation procedure was implemented to reconstruct 3D geometry of the RCCA. The reconstructed RCCA was compared to the vessel geometry using a global threshold-based segmentation method. Computational fluid dynamics was applied to compute the velocity field and WSS distribution along the RCCA. RESULTS eXIA 160-enhanced micro-CT allowed clear visualization and assessment of the RCCA in all eight animals. No adverse biological effects were observed from the use of eXIA 160. Segmentation using local threshold values generated more accurate RCCA geometry than the global threshold-based approach. Mouse-specific velocity data and the RCCA geometry generated 3D WSS maps with high resolution, enabling quantitative analysis of WSS. In all animals, we observed low WSS upstream of the cast. Downstream of the cast, asymmetric WSS patterns were revealed with variation in size and location between animals. CONCLUSIONS eXIA 160 provided good contrast to reconstruct 3D vessel geometry and determine WSS patterns in the RCCA of the atherosclerotic mouse model. We established a novel local threshold-based segmentation protocol for RCCA reconstruction and WSS computation. The observed differences between animals indicate the necessity to use mouse-specific data for WSS analysis. For our future work, our protocol makes it possible to study in vivo WSS longitudinally over a growing plaque.
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Affiliation(s)
- Ruoyu Xing
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Wytemaweg 80, Ee2338, 3015CN, Rotterdam, The Netherlands
| | - David De Wilde
- IBiTech-bioMMeda, iMinds Medical IT, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - Gayle McCann
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Wytemaweg 80, Ee2338, 3015CN, Rotterdam, The Netherlands
| | - Yanto Ridwan
- Department of Genetics, Erasmus MC, Wytemaweg 80, Ee720, 3015CN, Rotterdam, The Netherlands
| | - Jelle T. C. Schrauwen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Wytemaweg 80, Ee2338, 3015CN, Rotterdam, The Netherlands
| | - Anton F. W. van der Steen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Wytemaweg 80, Ee2338, 3015CN, Rotterdam, The Netherlands
| | - Frank J. H. Gijsen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Wytemaweg 80, Ee2338, 3015CN, Rotterdam, The Netherlands
| | - Kim Van der Heiden
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Wytemaweg 80, Ee2338, 3015CN, Rotterdam, The Netherlands
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Assessment of shear stress related parameters in the carotid bifurcation using mouse-specific FSI simulations. J Biomech 2016; 49:2135-2142. [DOI: 10.1016/j.jbiomech.2015.11.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 11/07/2015] [Indexed: 01/07/2023]
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De Wilde D, Trachet B, De Meyer G, Segers P. The influence of anesthesia and fluid-structure interaction on simulated shear stress patterns in the carotid bifurcation of mice. J Biomech 2016; 49:2741-2747. [PMID: 27342001 DOI: 10.1016/j.jbiomech.2016.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/04/2016] [Accepted: 06/07/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND Low and oscillatory wall shear stresses (WSS) near aortic bifurcations have been linked to the onset of atherosclerosis. In previous work, we calculated detailed WSS patterns in the carotid bifurcation of mice using a Fluid-structure interaction (FSI) approach. We subsequently fed the animals a high-fat diet and linked the results of the FSI simulations to those of atherosclerotic plaque location on a within-subject basis. However, these simulations were based on boundary conditions measured under anesthesia, while active mice might experience different hemodynamics. Moreover, the FSI technique for mouse-specific simulations is both time- and labor-intensive, and might be replaced by simpler and easier Computational Fluid Dynamics (CFD) simulations. The goal of the current work was (i) to compare WSS patterns based on anesthesia conditions to those representing active resting and exercising conditions; and (ii) to compare WSS patterns based on FSI simulations to those based on steady-state and transient CFD simulations. METHODS For each of the 3 computational techniques (steady state CFD, transient CFD, FSI) we performed 5 simulations: 1 for anesthesia, 2 for conscious resting conditions and 2 more for conscious active conditions. The inflow, pressure and heart rate were scaled according to representative in vivo measurements obtained from literature. RESULTS When normalized by the maximal shear stress value, shear stress patterns were similar for the 3 computational techniques. For all activity levels, steady state CFD led to an overestimation of WSS values, while FSI simulations yielded a clear increase in WSS reversal at the outer side of the sinus of the external carotid artery that was not visible in transient CFD-simulations. Furthermore, the FSI simulations in the highest locomotor activity state showed a flow recirculation zone in the external carotid artery that was not present under anesthesia. This recirculation went hand in hand with locally increased WSS reversal. CONCLUSIONS Our data show that FSI simulations are not necessary to obtain normalized WSS patterns, but indispensable to assess the oscillatory behavior of the WSS in mice. Flow recirculation and WSS reversal at the external carotid artery may occur during high locomotor activity while they are not present under anesthesia. These phenomena might thus influence plaque formation to a larger extent than what was previously assumed.
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Affiliation(s)
- David De Wilde
- IBiTech-bioMMeda, Ghent University-IMinds Medical IT, Ghent, Belgium
| | - Bram Trachet
- IBiTech-bioMMeda, Ghent University-IMinds Medical IT, Ghent, Belgium; Institute of Bioengineering, EPFL, Lausanne, Switzerland.
| | - Guido De Meyer
- Division of Physiopharmacology, University of Antwerp, Antwerp, Belgium
| | - Patrick Segers
- IBiTech-bioMMeda, Ghent University-IMinds Medical IT, Ghent, Belgium
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Pfenniger A, Meens MJ, Pedrigi RM, Foglia B, Sutter E, Pelli G, Rochemont V, Petrova TV, Krams R, Kwak BR. Shear stress-induced atherosclerotic plaque composition in ApoE(-/-) mice is modulated by connexin37. Atherosclerosis 2015; 243:1-10. [PMID: 26342936 DOI: 10.1016/j.atherosclerosis.2015.08.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 08/17/2015] [Accepted: 08/21/2015] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Shear stress patterns influence atherogenesis and plaque stability; low laminar shear stress (LLSS) promotes unstable plaques whereas oscillatory shear stress (OSS) induces more stable plaques. Endothelial connexin37 (Cx37) expression is also regulated by shear stress, which may contribute to localization of atherosclerotic disease. Moreover, Cx37 reduces initiation of atherosclerosis by inhibiting monocyte adhesion. The present work investigates the effect of Cx37 on the phenotype of plaques induced by LLSS or OSS. METHODS Shear stress-modifying casts were placed around the common carotid artery of ApoE(-/-) or ApoE(-/-)Cx37(-/-) mice, and animals were placed on a high-cholesterol diet for 6 or 9 weeks. Atherosclerotic plaque size and composition were assessed by immunohistochemistry. RESULTS Plaque size in response to OSS was increased in ApoE(-/-)Cx37(-/-) mice compared to ApoE(-/-) animals. Most plaques contained high lipid and macrophage content and a low amount of collagen. In ApoE(-/-) mice, macrophages were more prominent in LLSS than OSS plaques. This difference was reversed in ApoE(-/-)Cx37(-/-) animals, with a predominance of macrophages in OSS plaques. The increase in macrophage content in ApoE(-/-)Cx37(-/-) OSS plaques was mainly due to increased accumulation of M1 and Mox macrophage subtypes. Cx37 expression in macrophages did not affect their proliferation or their polarization in vitro. CONCLUSION Cx37 deletion increased the size of atherosclerotic lesions in OSS regions and abrogated the development of a stable plaque phenotype under OSS in ApoE(-/-) mice. Hence, local hemodynamic factors may modify the risk for adverse atherosclerotic disease outcomes associated to a polymorphism in the human Cx37 gene.
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Affiliation(s)
- A Pfenniger
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - M J Meens
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - R M Pedrigi
- Department of Bioengineering, Imperial College, London, UK
| | - B Foglia
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - E Sutter
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - G Pelli
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - V Rochemont
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland
| | - T V Petrova
- Department of Oncology, CHUV and University of Lausanne, Epalinges, Switzerland
| | - R Krams
- Department of Bioengineering, Imperial College, London, UK
| | - B R Kwak
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Department of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland.
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