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Alie N, Eldib M, Fayad ZA, Mani V. Inflammation, Atherosclerosis, and Coronary Artery Disease: PET/CT for the Evaluation of Atherosclerosis and Inflammation. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2015; 8:13-21. [PMID: 25674025 PMCID: PMC4294600 DOI: 10.4137/cmc.s17063] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/16/2014] [Accepted: 11/20/2014] [Indexed: 12/16/2022]
Abstract
Atherosclerosis is a prevalent cardiovascular disease marked by inflammation and the formation of plaque within arterial walls. As the disease progresses, there is an increased risk of major cardiovascular events. Owing to the nature of atherosclerosis, it is imperative to develop methods to further understand the physiological implications and progression of the disease. The combination of positron emission tomography (PET)/computed tomography (CT) has proven to be promising for the evaluation of atherosclerotic plaques and inflammation within the vessel walls. The utilization of the radiopharmaceutical tracer, 18F-fluorodeoxyglucose (18F-FDG), with PET/CT is invaluable in understanding the pathophysiological state involved in atherosclerosis. In this review, we will discuss the use of 18F-FDG-PET/CT imaging for the evaluation of atherosclerosis and inflammation both in preclinical and clinical studies. The potential of more specific novel tracers will be discussed. Finally, we will touch on the potential benefits of using the newly introduced combined PET/magnetic resonance imaging (MRI) for non-invasive imaging of atherosclerosis.
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Affiliation(s)
- Nadia Alie
- Translational and Molecular Imaging Institute, Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mootaz Eldib
- Translational and Molecular Imaging Institute, Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Zahi A Fayad
- Translational and Molecular Imaging Institute, Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Venkatesh Mani
- Translational and Molecular Imaging Institute, Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Teresa Albelda M, Garcia-España E, Frias JC. Visualizing the atherosclerotic plaque: a chemical perspective. Chem Soc Rev 2014; 43:2858-76. [PMID: 24526041 DOI: 10.1039/c3cs60410a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atherosclerosis is the major underlying pathologic cause of coronary artery disease. An early detection of the disease can prevent clinical sequellae such as angina, myocardial infarction, and stroke. The different imaging techniques employed to visualize the atherosclerotic plaque provide information of diagnostic and prognostic value. Furthermore, the use of contrast agents helps to improve signal-to-noise ratio providing better images. For nuclear imaging techniques and optical imaging these agents are absolutely necessary. We report on the different contrast agents that have been used, are used or may be used in future in animals, humans, or excised tissues for the distinct imaging modalities for atherosclerotic plaque imaging.
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Affiliation(s)
- Ma Teresa Albelda
- Universidad de Valencia, Instituto de Ciencia Molecular, Edificio de Institutos de Paterna, c/ Catedrático José Beltrán 2, 46071 Valencia, Spain
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Niccoli Asabella A, Ciccone MM, Cortese F, Scicchitano P, Gesualdo M, Zito A, Di Palo A, Angiletta D, Regina G, Marzullo A, Rubini G. Higher reliability of 18F-FDG target background ratio compared to standardized uptake value in vulnerable carotid plaque detection: a pilot study. Ann Nucl Med 2014; 28:571-9. [PMID: 24737136 DOI: 10.1007/s12149-014-0850-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/01/2014] [Indexed: 11/28/2022]
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Orbay H, Hong H, Zhang Y, Cai W. Positron emission tomography imaging of atherosclerosis. Theranostics 2013; 3:894-902. [PMID: 24312158 PMCID: PMC3841339 DOI: 10.7150/thno.5506] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/27/2013] [Indexed: 12/21/2022] Open
Abstract
Atherosclerosis-related cardiovascular events are the leading causes of death in the industrialized world. Atherosclerosis develops insidiously and the initial manifestation is usually sudden cardiac death, stroke, or myocardial infarction. Molecular imaging is a valuable tool to identify the disease at an early stage before fatal manifestations occur. Among the various molecular imaging techniques, this review mainly focuses on positron emission tomography (PET) imaging of atherosclerosis. The targets and pathways that have been investigated to date for PET imaging of atherosclerosis include: glycolysis, cell membrane metabolism (phosphatidylcholine synthesis), integrin αvβ3, low density lipoprotein (LDL) receptors (LDLr), natriuretic peptide clearance receptors (NPCRs), fatty acid synthesis, vascular cell adhesion molecule-1 (VCAM-1), macrophages, platelets, etc. Many PET tracers have been investigated clinically for imaging of atherosclerosis. Early diagnosis of atherosclerotic lesions by PET imaging can help to prevent the premature death caused by atherosclerosis, and smooth translation of promising PET tracers into the clinic is critical to the benefit of patients.
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Zhao Y, Zhao S, Kuge Y, Strauss HW, Blankenberg FG, Tamaki N. Attenuation of Apoptosis by Telmisartan in Atherosclerotic Plaques of Apolipoprotein E
−/−
Mice: Evaluation Using Technetium 99m–Annexin A5. Mol Imaging 2013. [DOI: 10.2310/7290.2012.00045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Yan Zhao
- From the Departments of Tracer Kinetics and Bioanalysis and Nuclear Medicine, Graduate School of Medicine, and Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan; Department of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and Department of Pediatric Radiology, Stanford University School of Medicine, Palo Alto, CA
| | - Songji Zhao
- From the Departments of Tracer Kinetics and Bioanalysis and Nuclear Medicine, Graduate School of Medicine, and Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan; Department of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and Department of Pediatric Radiology, Stanford University School of Medicine, Palo Alto, CA
| | - Yuji Kuge
- From the Departments of Tracer Kinetics and Bioanalysis and Nuclear Medicine, Graduate School of Medicine, and Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan; Department of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and Department of Pediatric Radiology, Stanford University School of Medicine, Palo Alto, CA
| | - H. William Strauss
- From the Departments of Tracer Kinetics and Bioanalysis and Nuclear Medicine, Graduate School of Medicine, and Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan; Department of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and Department of Pediatric Radiology, Stanford University School of Medicine, Palo Alto, CA
| | - Francis G. Blankenberg
- From the Departments of Tracer Kinetics and Bioanalysis and Nuclear Medicine, Graduate School of Medicine, and Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan; Department of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and Department of Pediatric Radiology, Stanford University School of Medicine, Palo Alto, CA
| | - Nagara Tamaki
- From the Departments of Tracer Kinetics and Bioanalysis and Nuclear Medicine, Graduate School of Medicine, and Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan; Department of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; and Department of Pediatric Radiology, Stanford University School of Medicine, Palo Alto, CA
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Dimastromatteo J, Broisat A, Perret P, Ahmadi M, Boturyn D, Dumy P, Fagret D, Riou LM, Ghezzi C. In vivo molecular imaging of atherosclerotic lesions in ApoE-/- mice using VCAM-1-specific, 99mTc-labeled peptidic sequences. J Nucl Med 2013; 54:1442-9. [PMID: 23719858 DOI: 10.2967/jnumed.112.115675] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Vascular cell adhesion molecule 1 (VCAM-1) plays a major role in the chronic inflammatory processes involved in vulnerable atherosclerotic plaque development. We previously showed that the (99m)Tc-labeled major histocompatibility complex 1-derived peptide B2702p bound specifically to VCAM-1 and allowed the ex vivo imaging of atherosclerotic lesions in Watanabe heritable hyperlipidemic rabbits. However, B2702p target-to-background ratio was suboptimal for the in vivo imaging of VCAM-1 expression in atherosclerotic lesions. To improve the target-to-background ratio, 20 derivatives of B2702p (B2702p1-B2702p20) were synthesized using the alanine scan methodology. We hypothesized that (99m)Tc-radiolabeled B2702p derivatives might allow the molecular imaging of VCAM-1 expression in an experimental model of atherosclerosis. METHODS A mouse model of focal atherosclerotic plaque development induced by left carotid artery ligation in apolipoprotein E double-knockout (ApoE(-/-)) mice was used (n = 82). (99m)Tc-B2702p and (99m)Tc-B2702p1-(99m)Tc-B2702p20 were injected intravenously in anesthetized animals 3 wk after the ligation. Whole-body planar imaging was performed for 3 h. SPECT imaging of 6 additional ligated ApoE(-/-) mice was also performed with (99m)Tc-B2702p1. The animals were then euthanized, and the biodistribution of (99m)Tc-labeled peptides was evaluated by γ-well counting of excised organs. Expression of VCAM-1 in the ligated and contralateral carotid arteries was evaluated by immunohistology. RESULTS Robust VCAM-1 immunostaining was observed in the left carotid atherosclerotic lesions as a consequence of artery ligation, whereas no VCAM-1 expression was detected in the contralateral carotid artery. Among all evaluated peptides, (99m)Tc-B2702p1 exhibited the most favorable properties. By γ-well counting, there was a significant 2.0-fold increase in the (99m)Tc-B2702p1 left-to-right carotid artery activity ratio (2.6 ± 0.6) and a 3.4-fold increase in the left carotid-to-blood activity ratio (1.4 ± 0.4) in comparison to (99m)Tc-B2702p (1.3 ± 0.2 and 0.4 ± 0.1, respectively, P < 0.05 for both comparisons). Similarly, planar image quantification indicated a higher left-to-right carotid activity ratio in (99m)Tc-B2702p1- than in (99m)Tc-B2702p-injected mice (1.2 ± 0.1 vs. 1.0 ± 0.0, respectively, P < 0.05). Finally, a significantly higher (99m)Tc-B2702p1 activity in the left than in the right carotid artery was observed by SPECT imaging (2.2 ± 0.4 vs. 1.4 ± 0.3 cpm/mm(2)/injected dose, respectively, P < 0.05). CONCLUSION (99m)Tc-B2702p1 is a potentially useful radiotracer for the in vivo molecular imaging of VCAM-1 expression in atherosclerotic plaques.
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Hag AMF, Ripa RS, Pedersen SF, Bodholdt RP, Kjaer A. Small animal positron emission tomography imaging and in vivo studies of atherosclerosis. Clin Physiol Funct Imaging 2013; 33:173-85. [PMID: 23522010 DOI: 10.1111/cpf.12017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 11/30/2012] [Indexed: 12/31/2022]
Abstract
Atherosclerosis is a growing health challenge globally, and despite our knowledge of the disease has increased over the last couple of decades, many unanswered questions remain. As molecular imaging can be used to visualize, characterize and measure biological processes at the molecular and cellular levels in living systems, this technology represents an opportunity to investigate some of these questions in vivo. In addition, molecular imaging may be translated into clinical use and eventually pave the way for more personalized treatment regimes in patients. Here, we review the current knowledge obtained from in vivo positron emission tomography studies of atherosclerosis performed in small animals.
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Affiliation(s)
- Anne Mette Fisker Hag
- Cluster for Molecular Imaging, Faculty of Health and Medical Sciences, Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
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Nishigori K, Temma T, Yoda K, Onoe S, Kondo N, Shiomi M, Ono M, Saji H. Radioiodinated peptide probe for selective detection of oxidized low density lipoprotein in atherosclerotic plaques. Nucl Med Biol 2012; 40:97-103. [PMID: 23157986 DOI: 10.1016/j.nucmedbio.2012.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/30/2012] [Accepted: 08/06/2012] [Indexed: 01/25/2023]
Abstract
INTRODUCTION Despite the significant effort in developing radioprobes for atherosclerosis, few have low molecular weight. Oxidized LDL (OxLDL), a highly proinflammatory and proatherogenic factor that is abundant in atherosclerotic plaques, plays a pivotal role in plaque destabilization, which makes OxLDL a relevant probe target. We developed a radioiodinated short peptide, AHP7, as a low molecular weight probe for specific OxLDL imaging and evaluated its utility using myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits (WHHLMI). METHODS [¹²⁵I]AHP7 was designed and synthesized based on the sequence of Asp-hemolysin, an OxLDL binding protein extracted from Aspergillus fumigatus. In vitro binding studies with OxLDL having varying degrees of oxidation were performed. Radioactivity accumulation in the aorta was measured 30 min post-administration in rabbits. Autoradiography and histological studies were performed using serial aorta sections. A radioiodinated scrambled peptide ([¹²⁵I]AHP scramble) was used as a negative control. RESULTS [¹²⁵I]AHP7 bound to OxLDL in proportion to the degree of oxidation (R=0.91, P<0.0001) and was inhibited by unlabeled AHP7 in a concentration-dependent manner. The aorta accumulation level and aorta/blood and aorta/muscle ratios of [¹²⁵I]AHP7 in WHHLMI were 2.8-, 1.3- and 1.8-fold higher, respectively, than those in control rabbits (P<0.001). Co-administration of AHP7 significantly reduced [¹²⁵I]AHP7 radioactivity in aorta sections (P<0.0001). Regional radioactivity levels in the aorta sections showed nonuniformity but similarity to the immunohistochemical OxLDL density. CONCLUSIONS The potential of radioiodinated AHP7 for selectively imaging OxLDL was demonstrated both in vitro and in vivo.
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Affiliation(s)
- Kantaro Nishigori
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
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Temma T, Saji H. Radiolabelled probes for imaging of atherosclerotic plaques. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2012; 2:432-447. [PMID: 23145360 PMCID: PMC3484420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 07/20/2012] [Indexed: 06/01/2023]
Abstract
Cardiovascular disease is the leading cause of death worldwide. Unstable atherosclerotic plaques are prone to rupture followed by thrombus formation, vessel stenosis, and occlusion and frequently lead to acute myocardial infarction and brain infarction. As such, unstable plaques represent an important diagnostic target in clinical settings and the specific diagnosis of unstable plaques would enable preventive treatments for cardiovascular disease. To date, various imaging methods such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), and intravascular ultrasound (IVUS) have been widely used clinically. Although these methods have advantages in terms of spatial resolution and the ability to make detailed identification of morphological alterations such as calcifications and vessel stenosis, these techniques require skill or expertise to discriminate plaque instability, which is essential for early diagnosis and treatment and can present difficulties for quantitative estimation. On the other hand, nuclear imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) can noninvasively collect quantitative information on the expression levels of functional molecules and metabolic activities in vivo and thus provide functional diagnoses of unstable plaques with high sensitivity. Specifically, unstable plaques are characterized by an abundance of invasive inflammatory cells (macrophages), increased oxidative stress that increases oxidized LDL and its receptor expressed on cells in the lesions, increased occurrence of apoptosis of macrophages and other cells involved in disease progression, increased protease expression and activity, and finally thrombus formation triggered by plaque rupture, which is the most important mechanism leading to the onset of infarctions and ischemic sudden death. Therefore, these characteristics can all be targets for molecular imaging by PET and SPECT. In this paper, we review the present state and future of radiolabelled probes that have been developed for detecting atherosclerotic unstable plaques with nuclear imaging techniques.
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Affiliation(s)
- Takashi Temma
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
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Broisat A, Hernot S, Toczek J, De Vos J, Riou LM, Martin S, Ahmadi M, Thielens N, Wernery U, Caveliers V, Muyldermans S, Lahoutte T, Fagret D, Ghezzi C, Devoogdt N. Nanobodies targeting mouse/human VCAM1 for the nuclear imaging of atherosclerotic lesions. Circ Res 2012; 110:927-37. [PMID: 22461363 DOI: 10.1161/circresaha.112.265140] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE A noninvasive tool allowing the detection of vulnerable atherosclerotic plaques is highly needed. By combining nanomolar affinities and fast blood clearance, nanobodies represent potential radiotracers for cardiovascular molecular imaging. Vascular cell adhesion molecule-1 (VCAM1) constitutes a relevant target for molecular imaging of atherosclerotic lesions. OBJECTIVE We aimed to generate, radiolabel, and evaluate anti-VCAM1 nanobodies for noninvasive detection of atherosclerotic lesions. METHODS AND RESULTS Ten anti-VCAM1 nanobodies were generated, radiolabeled with technetium-99m, and screened in vitro on mouse and human recombinant VCAM1 proteins and endothelial cells and in vivo in apolipoprotein E-deficient (ApoE(-/-)) mice. A nontargeting control nanobody was used in all experiments to demonstrate specificity. All nanobodies displayed nanomolar affinities for murine VCAM1. Flow cytometry analyses using human human umbilical vein endothelial cells indicated murine and human VCAM1 cross-reactivity for 6 of 10 nanobodies. The lead compound cAbVCAM1-5 was cross-reactive for human VCAM1 and exhibited high lesion-to-control (4.95±0.85), lesion-to-heart (8.30±1.11), and lesion-to-blood ratios (4.32±0.48) (P<0.05 versus control C57Bl/6J mice). Aortic arch atherosclerotic lesions of ApoE(-/-) mice were successfully identified by single-photon emission computed tomography imaging. (99m)Tc-cAbVCAM1-5 binding specificity was demonstrated by in vivo competition experiments. Autoradiography and immunohistochemistry further confirmed cAbVCAM1-5 uptake in VCAM1-positive lesions. CONCLUSIONS The (99m)Tc-labeled, anti-VCAM1 nanobody cAbVCAM1-5 allowed noninvasive detection of VCAM1 expression and displayed mouse and human cross-reactivity. Therefore, this study demonstrates the potential of nanobodies as a new class of radiotracers for cardiovascular applications. The nanobody technology might evolve into an important research tool for targeted imaging of atherosclerotic lesions and has the potential for fast clinical translation.
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Affiliation(s)
- Alexis Broisat
- Laboratoire des Radiopharmaceutiques Bioclinique, INSERM 1039, Grenoble, France.
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Hayenga HN, Trache A, Trzeciakowski J, Humphrey JD. Regional atherosclerotic plaque properties in ApoE-/- mice quantified by atomic force, immunofluorescence, and light microscopy. J Vasc Res 2011; 48:495-504. [PMID: 21832839 DOI: 10.1159/000329586] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Accepted: 05/20/2011] [Indexed: 12/13/2022] Open
Abstract
Elucidating regional material properties of arterial tissue is fundamental to predicting transmural stresses and understanding how tissue stiffness influences cellular responses and vice versa. Atomic force microscopy (AFM) was used to measure point-wise the axial compressive stiffness of healthy aortas and atherosclerotic plaques at micron level separation distances. Cross sections of plaques were obtained from a widely used animal model of atherosclerosis (ApoE-/- mice). Median point-wise values of material stiffness were 18.7 and 1.5 kPa for the unloaded healthy wall (n = 25 specimens) and plaque (n = 18), respectively. When the healthy wall was distended uniformly during AFM testing, two mechanically distinct populations emerged from comparisons of normal cumulative distributions, with median values of 9.8 and 76.7 kPa (n = 16). The higher values of stiffness may have been due to extended elastin, which was not present in the plaques. Rather, most plaques were identified via standard and immunofluorescent histology to be largely lipid laden, and they exhibited a nearly homogeneous linear elastic behavior over the small AFM indentations. Understanding the mechanics and mechanobiological factors involved in lesion development and remodeling could lead to better treatments for those lesions that are vulnerable to rupture.
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Affiliation(s)
- H N Hayenga
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
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Liu K, Wang MW, Lin WY, Phung DL, Girgis MD, Wu AM, Tomlinson JS, Shen CKF. Molecular Imaging Probe Development using Microfluidics. Curr Org Synth 2011; 8:473-487. [PMID: 22977436 DOI: 10.2174/157017911796117205] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In this manuscript, we review the latest advancement of microfluidics in molecular imaging probe development. Due to increasing needs for medical imaging, high demand for many types of molecular imaging probes will have to be met by exploiting novel chemistry/radiochemistry and engineering technologies to improve the production and development of suitable probes. The microfluidic-based probe synthesis is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional systems. Numerous chemical reactions have been successfully performed in micro-reactors and the results convincingly demonstrate with great benefits to aid synthetic procedures, such as purer products, higher yields, shorter reaction times compared to the corresponding batch/macroscale reactions, and more benign reaction conditions. Several 'proof-of-principle' examples of molecular imaging probe syntheses using microfluidics, along with basics of device architecture and operation, and their potential limitations are discussed here.
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Affiliation(s)
- Kan Liu
- College of Electronics and Information Engineering, Wuhan Textile University, Wuhan, 430073, China
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Niki E. Do free radicals play causal role in atherosclerosis? Low density lipoprotein oxidation and vitamin E revisited. J Clin Biochem Nutr 2010; 48:3-7. [PMID: 21297905 PMCID: PMC3022060 DOI: 10.3164/jcbn.11-007fr] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 09/10/2010] [Indexed: 12/31/2022] Open
Abstract
Lipid peroxidation induced by free radicals has been implicated in the pathogenesis of various diseases. Numerous in vitro and animal studies show that oxidative modification of low density lipoprotein (LDL) is an important initial event of atherosclerosis. Vitamin E and other antioxidants inhibit low density lipoprotein oxidation efficiently in vitro, however, human clinical trials with vitamin E have not yielded positive results. The mixed results for vitamin E effect may be ascribed primarily to the two factors. Firstly low density lipoprotein oxidation proceeds by multiple pathways mediated not only by free radicals but also by other non-radical oxidants and vitamin E is effective only against free radical mediated oxidation. Secondly, in contrast to animal experiments, vitamin E is given at the latter stage where oxidation is no more important. Free radicals must play causal role in pathogenesis of atherosclerosis and vitamin E should be effective if given at right time to right subjects.
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Affiliation(s)
- Etsuo Niki
- Department of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan
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De Groeve K, Deschacht N, De Koninck C, Caveliers V, Lahoutte T, Devoogdt N, Muyldermans S, De Baetselier P, Raes G. Nanobodies as tools for in vivo imaging of specific immune cell types. J Nucl Med 2010; 51:782-9. [PMID: 20395332 DOI: 10.2967/jnumed.109.070078] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Nanobodies are single-domain antigen-binding fragments derived from heavy-chain antibodies that are devoid of light chains and occur naturally in Camelidae. We have shown before that their small size and high affinity and specificity for their target antigen make Nanobodies ideal probes for in vivo tumor imaging. In the present study, we have evaluated the use of Nanobodies as a generic method for imaging the in vivo biodistribution of specific immune cell types, using myeloid cells as an example. METHODS The cellular specificity of Nanobodies raised against murine bone marrow-derived dendritic cells was verified using flow cytometry on a range of myeloid and nonmyeloid cell types. The Nanobodies were then labeled with (99m)Tc and their biodistribution was analyzed using SPECT. The biodistribution was also assessed by measuring radioactivity in various organs and tissues. To verify whether the observed biodistribution was due to specific targeting through the antigen-binding loops, rather than retention in organs because of effects of the framework regions, we genetically grafted the antigen-binding loops of the Nanobodies onto the framework region of a Nanobody scaffold that by itself showed low background retention in the periphery. The cellular specificity and biodistribution of these grafted Nanobodies were determined as before. RESULTS Nb-DC2.1, which recognizes a wide range of myeloid cells, targets most strongly to the liver, spleen, and lungs. Nb-DC1.8, which recognizes immature bone marrow-derived dendritic cells in vitro, gives a much smaller signal in the liver and spleen than does Nb-DC2.1 but mainly targets to the lungs and gives a pronounced signal in the skin. Grafting of the antigen-binding loops of Nb-DC1.8 or Nb-DC2.1 to the scaffold of Nb-BCII10 alters the observed biodistribution of the Nanobodies to resemble that of the Nanobody from which the antigen-binding loops have been derived. CONCLUSION The observed in vivo biodistribution of the Nanobodies reflects the main in vivo locations of the cells recognized by the Nanobodies and is determined by the antigen-binding loops of the Nanobodies. Thus, Nanobodies represent elegant targeting probes for imaging the in vivo biodistribution of specific immune cell types.
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Affiliation(s)
- Kurt De Groeve
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
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