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King RM, Gounis MJ, Schmidt EJ, Leporati A, Gale EM, Bogdanov AA. Molecular Magnetic Resonance Imaging of Aneurysmal Inflammation Using a Redox Active Iron Complex. Invest Radiol 2023; 58:656-662. [PMID: 36822678 PMCID: PMC10401906 DOI: 10.1097/rli.0000000000000960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
OBJECTIVES Inflammation plays a key role in driving brain aneurysmal instability and rupture, but clinical tools to noninvasively differentiate between inflamed and stable aneurysms are lacking. We hypothesize that imaging oxidative changes in the aneurysmal microenvironment driven by myeloid inflammatory cells may represent a noninvasive biomarker to evaluate rupture risk. In this study, we performed initial evaluation of the oxidatively activated probe Fe-PyC3A as a tool for magnetic resonance imaging (MRI) of inflammation in a rabbit model of saccular aneurysm. MATERIALS AND METHODS The difference in longitudinal relaxivity ( r1 ) in reduced and oxidized states of Fe-PyC3A was measured in water and blood plasma phantoms at 3 T. A rabbit saccular aneurysm model was created by endovascular intervention/elastinolysis with subsequent decellularization in situ. Rabbits were imaged at 4 weeks (n = 4) or 12 weeks (n = 4) after aneurysmal induction, when luminal levels of inflammation reflected by the presence of myeloperoxidase positive cells are relatively high and low, respectively, using a 3 T clinical scanner. Both groups were imaged dynamically using a 2-dimensional T1-weighted fast field echo pulse MRI sequence before and up to 4 minutes postinjection of Fe-PyC3A. Dynamic imaging was then repeated after an injection of gadobutrol (0.1 mmol/kg) as negative control probe. Rabbits from the 12-week aneurysm group were also imaged before and 20 minutes and 3 hours after injection of Fe-PyC3A using an axial respiratory gated turbo-spin echo (TSE) pulse sequence with motion-sensitized driven equilibrium (MSDE) preparation. The MSDE/TSE imaging was repeated before, immediately after dynamic acquisition (20 minutes postinjection), and 3 hours after injection of gadobutrol. Aneurysmal enhancement ratios (ERs) were calculated by dividing the postinjection aneurysm versus skeletal muscle contrast ratio by the preinjection contrast ratio. After imaging, the aneurysms were excised and inflammatory infiltrate was characterized by fluorometric detection of myeloperoxidase activity and calprotectin immunostaining, respectively. RESULTS In vitro relaxometry showed that oxidation of Fe-PyC3A by hydrogen peroxide resulted in a 15-fold increase of r1 at 3 T. Relaxometry in the presence of blood plasma showed no more than a 10% increase of r1 , indicating the absence of strong interaction of Fe-PyC3A with plasma proteins. Dynamic imaging with Fe-PyC3A generated little signal enhancement within the blood pool or adjacent muscle but did generate a transient increase in aneurysmal ER that was significantly greater 4 weeks versus 12 weeks after aneurysm induction (1.6 ± 0.30 vs 1.2 ± 0.03, P < 0.05). Dynamic imaging with gadobutrol generated strong aneurysmal enhancement, but also strong enhancement of the blood and muscle resulting in smaller relative ER change. In the 12-week group of rabbits, MSDE/TSE imaging showed that ER values measured immediately after dynamic MRI (20 minutes postinjection) were significantly higher ( P < 0.05) in the case of Fe-PyC3A (1.25 ± 0.06) than for gadobutrol injection (1.03 ± 0.03). Immunohistochemical corroboration using anticalprotectin antibody showed that leukocyte infiltration into the vessel walls and luminal thrombi was significantly higher in the 4-week group versus 12-week aneurysms (123 ± 37 vs 18 ± 7 cells/mm 2 , P < 0.05). CONCLUSIONS Magnetic resonance imaging using Fe-PyC3A injection in dynamic or delayed acquisition modes was shown to generate a higher magnetic resonance signal enhancement in aneurysms that exhibit higher degree of inflammation. The results of our pilot experiments support further evaluation of MRI using Fe-PyC3A as a noninvasive marker of aneurysmal inflammation.
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Affiliation(s)
- Robert M King
- From the Department of Radiology and New England Center for Stroke Research, UMASS Chan Medical School, Worcester
| | - Matthew J Gounis
- From the Department of Radiology and New England Center for Stroke Research, UMASS Chan Medical School, Worcester
| | - Eric J Schmidt
- From the Department of Radiology and New England Center for Stroke Research, UMASS Chan Medical School, Worcester
| | - Anita Leporati
- From the Department of Radiology and New England Center for Stroke Research, UMASS Chan Medical School, Worcester
| | - Eric M Gale
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown
| | - Alexei A Bogdanov
- From the Department of Radiology and New England Center for Stroke Research, UMASS Chan Medical School, Worcester
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The effects of brewers' spent grain on high-fat diet-induced fatty liver. Biochem Biophys Res Commun 2022; 616:49-55. [PMID: 35636255 DOI: 10.1016/j.bbrc.2022.05.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/09/2022] [Accepted: 05/15/2022] [Indexed: 11/20/2022]
Abstract
Obesity drives nonalcoholic fatty liver disease (NAFLD). This study investigated the effects of dietary brewers' spent grain (BSG) supplementation on obesity-induced NAFLD. Mice fed a high-fat diet supplemented with 30% BSG (HFD30) had reduced body weight and decreased plasma total cholesterol (TC) concentrations compared with HFD-fed mice. Retroperitoneal white adipose tissue (RWAT) and liver weights were reduced. Consistent with reduced hepatic triacylglycerol, TC, and non-esterified fatty acid concentrations, HFD30-fed mice showed reduced hepatic steatosis. 3-hydroxy-3-methylglutaryl-CoA reductase and low-density lipoprotein receptor genes were increased, whereas carnitine palmitoyltransferase 1 alpha, ATP-binding cassette subfamily A member 1 (Abca1), and cholesterol 7 alpha-hydroxylase genes were upregulated in the liver of HFD30-fed mice. Abca1 gene expression was also increased in epididymal WAT and RWAT of HFD30-fed mice. BSG supplementation increased and decreased fecal fat and bile acid concentrations, respectively. Taken together, BSG supplementation reduced HFD-induced hepatic lipid accumulation by increasing fatty acid oxidation and bile acid synthesis in the liver as well as decreasing lipid absorption in the intestine.
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Reichardt W, von Elverfeldt D. Preclinical Applications of Magnetic Resonance Imaging in Oncology. Recent Results Cancer Res 2020; 216:405-437. [PMID: 32594394 DOI: 10.1007/978-3-030-42618-7_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The evolving possibilities of molecular imaging (MI) are fundamentally changing the way we look at cancer, with imaging paradigms now shifting away from basic morphological measures toward the longitudinal assessment of functional, metabolic, cellular, and molecular information in vivo. Recent developments of imaging methodology and probe molecules utilizing the vast number of novel animal models of human cancers have enhanced our ability to non-invasively characterize neoplastic tissue and follow anticancer treatments. While preclinical molecular imaging offers a whole palette of excellent methodology to choose from, we will focus on magnetic resonance imaging (MRI) techniques, since they provide excellent molecular imaging capabilities and bear high potential for clinical translation. Prerequisites and consequences of using animal models as surrogates of human cancers in preclinical molecular imaging are outlined. We present physical principles, values, and limitations of MRI as molecular imaging modality and comment on its high potential to non-invasively assess information on metabolism, hypoxia, angiogenesis, and cell trafficking in preclinical cancer research.
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Affiliation(s)
- Wilfried Reichardt
- Medical Physics, Department of Radiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,German Consortium for Translational Cancer Research (DKTK), Heidelberg, Germany. .,German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Dominik von Elverfeldt
- Medical Physics, Department of Radiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Cui Y, Zhang C, Li X, Liu H, Yin B, Xu T, Zhang Y, Wang D. Intravoxel Incoherent Motion Diffusion-weighted Magnetic Resonance Imaging for Monitoring the Early Response to ZD6474 from Nasopharyngeal Carcinoma in Nude Mouse. Sci Rep 2015; 5:16389. [PMID: 26574153 PMCID: PMC4648100 DOI: 10.1038/srep16389] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/14/2015] [Indexed: 01/02/2023] Open
Abstract
Early therapeutic effects of anti-angiogenic agent ZD6474 upon nasopharyngeal carcinoma (NPC) in nude mouse were monitored by using intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI). Mice bearing NPC underwent IVIM DWI at baseline and after 1, 3, and 7 days of treatment with ZD6474 or vehicle (n = 12 per group). Parameters of apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion fraction (f), and blood pseudodiffusion coefficient (D*) at different time points were compared between the two groups or within the treated group. In the treated group, the perfusion-related parameters f and D* of the tumors decreased significantly on day 1 while the diffusion-related parameters ADC and D were significantly higher beginning on day 3 compared with the control group. The decreases in f on day 1 and D* on day 3 were moderately correlated with the smaller tumor size change on day 7. Moderate correlations were established between MVD and f and D* as well as between increased TUNEL or decreased Ki-67 index and ADC and D. This study supports that IVIM DWI is sensitive to detect the ZD6474-induced changes in NPC in nude mouse and the f parameter could predict early response to anti-angiogenic treatment.
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Affiliation(s)
- Yanfen Cui
- Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Caiyuan Zhang
- Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Xiaoming Li
- Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Huanhuan Liu
- Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Bing Yin
- Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Tianyong Xu
- MR Advanced Application and Research Center, GE Healthcare China, Shanghai 201203, China
| | - Yong Zhang
- MR Advanced Application and Research Center, GE Healthcare China, Shanghai 201203, China
| | - Dengbin Wang
- Department of Radiology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
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Kwon HJ, Shim WH, Cho G, Cho HJ, Jung HS, Lee CK, Lee YS, Baek JH, Kim EJ, Suh JY, Sung YS, Woo DC, Kim YR, Kim JK. Simultaneous evaluation of vascular morphology, blood volume and transvascular permeability using SPION-based, dual-contrast MRI: imaging optimization and feasibility test. NMR IN BIOMEDICINE 2015; 28:624-632. [PMID: 25865029 DOI: 10.1002/nbm.3293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 06/04/2023]
Abstract
Exploiting ultrashort-T(E) (UTE) MRI, T1-weighted positive contrast can be obtained from superparamagnetic iron oxide nanoparticles (SPIONs), which are widely used as a robust T2-weighted, negative contrast agent on conventional MR images. Our study was designed (a) to optimize the dual-contrast MRI method using SPIONs and (b) to validate the feasibility of simultaneously evaluating the vascular morphology, blood volume and transvascular permeability using the dual-contrast effect of SPIONs. All studies were conducted using 3 T MRI. According to numerical simulation, 0.15 mM was the optimal blood SPION concentration for visualizing the positive contrast effect using UTE MRI (T(E) = 0.09 ms), and a flip angle of 40° could provide sufficient SPION-induced enhancement and acceptable measurement noise for UTE MR angiography. A pharmacokinetic study showed that this concentration can be steadily maintained from 30 to 360 min after the injection of 29 mg/kg of SPIONs. An in vivo study using these settings displayed image quality and CNR of SPION-enhanced UTE MR angiography (image quality score 3.5; CNR 146) comparable to those of the conventional, Gd-enhanced method (image quality score 3.8; CNR 148) (p > 0.05). Using dual-contrast MR images obtained from SPION-enhanced UTE and conventional spin- and gradient-echo methods, the transvascular permeability (water exchange index 1.76-1.77), cerebral blood volume (2.58-2.60%) and vessel caliber index (3.06-3.10) could be consistently quantified (coefficient of variation less than 9.6%; Bland-Altman 95% limits of agreement 0.886-1.111) and were similar to the literature values. Therefore, using the optimized setting of combined SPION-based MRI techniques, the vascular morphology, blood volume and transvascular permeability can be comprehensively evaluated during a single session of MR examination.
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Affiliation(s)
- Heon-Ju Kwon
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Woo Hyun Shim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
| | - Gyunggoo Cho
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Hyung Joon Cho
- Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Hoe Su Jung
- Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Chang Kyung Lee
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Yong Seok Lee
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Jin Hee Baek
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | | | - Ji-Yeon Suh
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
| | - Yu Sub Sung
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
| | - Dong-Cheol Woo
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
| | - Young Ro Kim
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Jeong Kon Kim
- Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asan Institute for Life Sciences, Seoul, South Korea
- Division of Magnetic Resonance, Korea Basic Science Institute, Cheongwon, Chungbuk, South Korea
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Abstract
Molecular imaging fundamentally changes the way we look at cancer. Imaging paradigms are now shifting away from classical morphological measures towards the assessment of functional, metabolic, cellular, and molecular information in vivo. Interdisciplinary driven developments of imaging methodology and probe molecules utilizing animal models of human cancers have enhanced our ability to non-invasively characterize neoplastic tissue and follow anti-cancer treatments. Preclinical molecular imaging offers a whole palette of excellent methodology to choose from. We will focus on positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques, since they provide excellent and complementary molecular imaging capabilities and bear high potential for clinical translation. Prerequisites and consequences of using animal models as surrogates of human cancers in preclinical molecular imaging are outlined. We present physical principles, values and limitations of PET and MRI as molecular imaging modalities and comment on their high potential to non-invasively assess information on hypoxia, angiogenesis, apoptosis, gene expression, metabolism, and cell trafficking in preclinical cancer research.
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Affiliation(s)
- Gunter Wolf
- University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany.
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Wang P, Schuetz C, Ross A, Dai G, Markmann JF, Moore A. Immune rejection after pancreatic islet cell transplantation: in vivo dual contrast-enhanced MR imaging in a mouse model. Radiology 2012; 266:822-30. [PMID: 23264346 DOI: 10.1148/radiol.12121129] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To detect adoptively transferred immune attack in a mouse model of islet cell transplantation by using a long-circulating paramagnetic T1 contrast agent, a protected graft copolymer (PGC) that is covalently linked to gadolinium-diethylenetriaminepentaacetic acid with fluorescein isothiocyanate (Gd-DTPA-F), which accumulates in the sites of inflammation that are characterized by vascular disruption. MATERIALS AND METHODS All animal experiments were performed in compliance with institutional guidelines and approved by the subcommittee on research animal care. Six nonobese diabetic severe combined immunodeficiency mice received transplanted human islet cells under the kidney capsule and adoptively transferred 5 × 10(6) splenocytes from 6-week-old nonobese diabetic mice. These mice also served as control subjects for comparison of pre- and postadoptive transfer MR imaging results. Mice that received phosphate-buffered saline solution only were included as nonadoptive-transfer control subjects (n = 2). In vivo magnetic resonance (MR) imaging was performed before and 17 hours after intravenous injections of PGC-Gd-DTPA-F, followed by histologic examination. Statistical differences were analyzed by means of a paired Student t test and repeated two-way analysis of variance. RESULTS MR imaging results showed significantly greater accumulation of PGC-Gd-DTPA-F in the graft area after immune attack initiated by adoptive transfer of splenocytes compared with that of the same area before the transfer (T1, 137.2 msec ± 39.3 and 239.5 msec ± 17.6, respectively; P < .001). These results were confirmed at histologic examination, which showed considerable leakage of the contrast agent into the islet cell interstitium. CONCLUSION PGC-Gd-DTPA-F-enhanced MR imaging allows for the in vivo assessment of vascular damage of the graft T cell challenge.
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Affiliation(s)
- Ping Wang
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Building 75, 149 13th St, Charlestown, MA 02129, USA
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Kang HW, Gupta S, Bogdanov A. Orthotopic expression of noggin protein in cancer cells inhibits human lung carcinoma growth in vivo. Mol Imaging Biol 2012; 14:480-8. [PMID: 21913026 DOI: 10.1007/s11307-011-0518-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE We explored the effect of Noggin protein expression on tumor growth in vivo by using fluorescence imaging. PROCEDURES Human lung carcinoma MV522 cells were transduced by using bicistronic (EGFP/Nog) or a control (EGFP) lentivirus at >95% efficacy. The transduced cells were implanted in athymic mice either individually or after mixing with DsRed2-expressing MV522 cells. RESULTS The expression of Noggin protein was demonstrated in EGFP+/Nog+ but not in EGFP+ cell lysates and conditioned media. Noggin did not inhibit tumor cell proliferation in vitro. Implantation of EGFP+ resulted in rapid tumor growth, whereas mice implanted with EGFP+/Nog+ either failed to develop tumors or developed smaller slowly proliferating ones. In the case of tumors grown from mixtures with DsRed2+ cells, only Noggin-expressing cells resulted in decreased tumor volumes with low vascular density and poorly developed stroma. CONCLUSION The effect of Noggin protein expression is a consequence of inhibition of stromal and/or endothelial proliferation in vivo.
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Affiliation(s)
- Hye-Won Kang
- Laboratory of Molecular Imaging Probes, Department of Radiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA, USA
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Bogdanov Jr AA, Mazzanti M, Castillo G, Bolotin E. Protected Graft Copolymer (PGC) in Imaging and Therapy: A Platform for the Delivery of Covalently and Non-Covalently Bound Drugs. Am J Cancer Res 2012; 2:553-76. [PMID: 22737192 PMCID: PMC3381344 DOI: 10.7150/thno.4070] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 02/17/2012] [Indexed: 12/13/2022] Open
Abstract
Initially developed in 1992 as an MR imaging agent, the family of protected graft copolymers (PGC) is based on a conjugate of polylysine backbone to which methoxypoly(ethylene glycol) (MPEG) chains are covalently linked in a random fasion via N-ε-amino groups. While PGC is relatively simple in terms of its chemcial composition and structure, it has proved to be a versatile platform for in vivo drug delivery. The advantages of poly amino acid backbone grafting include multiple available linking sites for drug and adaptor molecules. The grafting of PEG chains to PGC does not compromise biodegradability and does not result in measurable toxicity or immunogenicity. In fact, the biocompatablility of PGC has resulted in its being one of the few 100% synthetic non-proteinaceous macromolecules that has suceeded in passing the initial safety phase of clinical trials. PGC is capable of long circulation times after injection into the blood stream and as such found use early on as a carrier system for delivery of paramagnetic imaging compounds for angiography. Other PGC types were later developed for use in nuclear medicine and optical imaging applications in vivo. Recent developments in PGC-based drug carrier formulations include the use of zinc as a bridge between the PGC carrier and zinc-binding proteins and re-engineering of the PGC carrier as a covalent amphiphile that is capabe of binding to hydrophobic residues of small proteins and peptides. At present, PGC-based formulations have been developed and tested in various disease models for: 1) MR imaging local blood circulation in stroke, cancer and diabetes; 2) MR and nuclear imaging of blood volume and vascular permeability in inflammation; 3) optical imaging of proteolytic activity in cancer and inflammation; 4) delivery of platinum(II) compounds for treating cancer; 5) delivery of small proteins and peptides for treating diabetes, obesity and myocardial infarction. This review summarizes the experience accumulated by various research groups that chose to use PGC as a drug delivery platform.
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Medarova Z, Greiner DL, Ifediba M, Dai G, Bolotin E, Castillo G, Bogdanov A, Kumar M, Moore A. Imaging the pancreatic vasculature in diabetes models. Diabetes Metab Res Rev 2011; 27:767-72. [PMID: 22069257 PMCID: PMC3721374 DOI: 10.1002/dmrr.1249] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Vascular parameters, such as vascular volume, flow, and permeability, are important disease biomarkers for both type 1 and type 2 diabetes. Therefore, it is essential to develop approaches to monitor the changes in pancreatic microvasculature non-invasively. METHODS Here, we describe the application of the long-circulating, paramagnetic T1 contrast agent, protected Graft Copolymer bearing covalently linked gadolinium diethylenetriaminepentaacetic acid residues and labelled with fluorescein (PGC-GdDTPA-F) for the non-invasive semi-quantitative evaluation of vascular changes in diabetic models using magnetic resonance imaging. RESULTS We observed a significantly higher accumulation of protected graft copolymer bearing covalently linked gadolinium diethylenetriaminepentaacetic acid residues and labelled with fluorescein in the pancreata of BBDR rats induced to develop diabetes, as compared to non-diabetic controls at 1 h post-injection. No differences were seen in the blood pool, kidney, or muscle, indicating that the effect is specific to the diabetic pancreas. Fluorescence microscopy revealed a marked increase in contrast agent availability in the pancreas with the development of the pathology. Similar changes were noted in the homozygous Leprdb mouse model of type 2 diabetes. This effect appeared to result both from the increase of vascular volume and permeability. CONCLUSIONS High-molecular weight paramagnetic blood volume contrast agents are valuable for the in vivo definition of pancreatic microvasculature dynamics by magnetic resonance imaging. The increase in vascular volume and permeability, associated with diabetic inflammation, can be monitored non-invasively and semi-quantitatively by magnetic resonance imaging in diabetic BBDR rats. This imaging strategy represents a valuable research tool for better understanding of the pathologic process.
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Affiliation(s)
- Zdravka Medarova
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - Dale L. Greiner
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Marytheresa Ifediba
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - Guangping Dai
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | | | | | - Alexei Bogdanov
- Departments of Radiology and Cell Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Mohanraja Kumar
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
| | - Anna Moore
- Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA
- Correspondence to: Anna Moore, Molecular Imaging Laboratory, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Bldg.75, 13th St., Charlestown, MA 02129, USA
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Successful establishment of an orthotopic hepatoblastoma in vivo model in NOD/LtSz-scid IL2Rγnull mice. PLoS One 2011; 6:e23419. [PMID: 21853130 PMCID: PMC3154467 DOI: 10.1371/journal.pone.0023419] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 07/16/2011] [Indexed: 11/26/2022] Open
Abstract
Investigation of hepatoblastoma in experimental conditions contributes relevantly to a detailed understanding of tumor biology and the investigation of new treatment approaches. Most systematical analyses currently use subcutaneous xenografts. We established a reproducible intrahepatic model with the hepatoblastoma-cell lines HuH6 and HepT1. The cells were stably transfected with a plasmid vector encoding for Gaussia luciferase. HuH6 and HepT1 were injected intrasplenically in NOD/LtSz-scid IL2Rγnull mice. Mice were splenectomized in order to avoid intrasplenical tumor growth. Multifocal intrahepatic tumor growth was observed in 85% (11/13) of HuH6 tumors and 55% (5/9) of HepT1 tumors. Serum Alpha-fetoprotein and Gaussia luciferase increased 5 weeks after tumor-cell inoculation. Tumors were detected by MRI at this time point. Immunhistochemical analysis such as vascularity (CD31), proliferation index (Ki-67), cytokeratin 7 and distribution of β -catenin in intrahepatic tumors were different to subcutaneous tumors. We established a reproducible xenograft model for intrahepatic hepatoblastoma growth with a high tumor incidence. Monitoring of tumor cell viability was optimized by measuring GLuc. This model enables further experimental investigations of HB in a more physiological milieu as emphasized by the β-catenin distribution.
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Biomarqueurs en imagerie pour l’évaluation des nouvelles thérapies anticancéreuses. ONCOLOGIE 2010. [DOI: 10.1007/s10269-010-1870-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Kang HW, Walvick R, Bogdanov A. In vitro and In vivo imaging of antivasculogenesis induced by Noggin protein expression in human venous endothelial cells. FASEB J 2009; 23:4126-34. [PMID: 19692649 DOI: 10.1096/fj.08-127795] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Noggin protein is a potent bone morphogenetic protein (BMP) antagonist capable of inhibiting vasculogenesis even in the presence of provasculogenic VEGF and FGF-2. We found that human umbilical vein endothelial cells (HUVECs) do not express Noggin in culture and used these cells for modeling of antivasculogenesis. We hypothesized that high-efficiency transduction of HUVECs with bicistronic lentiviral vector encoding Noggin and enhanced green fluorescent protein (EGFP) enables direct visualization of Noggin effects in homogenous primary cell populations in vitro and in vivo. By comparing HUVECs transduced with a control GFP and GFP/Noggin expression cassettes, we showed that constitutive and orthotopic Noggin protein expression did not influence cell proliferation, down-regulated BMP-2 expression, and showed no effect on BMP receptor transcripts. We demonstrated that in contrast to GFP-only control, Noggin expression in endothelial cells abrogated endothelial migration in response to monolayer injury, blocked endothelial transmigration, and caused abrogation of cord formation in vitro. Adding exogenous BMP-4 restored the formation of cords. Imaging experiments in vivo investigated vessel formation in Matrigel implants in athymic mice by utilizing GFP imaging or magnetic resonance imaging of perfusion in the implants. Both approaches demonstrated the lack of functional vessel formation after the adoptive transfer of GFP/Noggin-expressing human endothelial cells in mice.
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Affiliation(s)
- Hye-Won Kang
- Department of Radiology, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester, MA 01655, USA
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Assessment of the early effects of 5,6-dimethylxanthenone-4-acetic acid using macromolecular contrast media-enhanced magnetic resonance imaging: ectopic versus orthotopic tumors. Int J Radiat Oncol Biol Phys 2008; 72:1198-207. [PMID: 18954713 DOI: 10.1016/j.ijrobp.2008.07.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 06/30/2008] [Accepted: 07/07/2008] [Indexed: 11/21/2022]
Abstract
PURPOSE To investigate the early effects of a vascular disrupting agent (VDA) in ectopic and orthotopic tumors by using macromolecular contrast media (MMCM)-enhanced magnetic resonance imaging (MMCM-MRI). METHODS AND MATERIALS The MMCM-MRI of ectopic and orthotopic MCA205 murine fibrosarcomas was performed using the intravascular contrast agent albumin-(gadopentetate dimeglumine)(35). Change in longitudinal relaxation rate (DeltaR1) was measured 24 hours after treatment with 5,6-dimethylxanthenone-4-acetic acid (DMXAA; 30 mg/kg) and used to compute tumor vascular volume and permeability. Correlative histologic and immunohistochemical evaluation was carried out, along with measurement of tumor necrosis factor alpha and vascular endothelial growth factor levels in whole tumor extracts using the enzyme-linked immunosorbent assay. RESULTS Orthotopic tumors showed higher vascular volume (p < 0.05) than ectopic tumors before treatment. Twenty-four hours after DMXAA treatment, a significant (p < 0.0001), but differential, decrease in DeltaR1 (70% in ectopic and 50% in orthotopic tumors) was observed compared with baseline estimates. Consistent with this observation, greater levels of tumor necrosis factor alpha, an important mediator of the antivascular activity of DMXAA, were measured in ectopic tumors 3 hours posttreatment compared with orthotopic tumors (p < 0.05). Immunohistochemical (CD31) and histologic (hematoxylin and eosin) sections of ectopic and orthotopic tumors showed highly tumor-selective vascular damage after treatment with the presence of viable surrounding normal tissue. CONCLUSIONS The MMCM-MRI provided early quantitative estimates of change in tumor perfusion after VDA treatment that showed good correlation with cytokine induction. Differences in the response of ectopic and orthotopic tumors highlight the influence of the host microenvironment in modulating the activity of VDAs.
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Abstract
Molecular imaging can allow the non-invasive assessment of biological and biochemical processes in living subjects. Such technologies therefore have the potential to enhance our understanding of disease and drug activity during preclinical and clinical drug development, which could aid decisions to select candidates that seem most likely to be successful or to halt the development of drugs that seem likely to ultimately fail. Here, with an emphasis on oncology, we review the applications of molecular imaging in drug development, highlighting successes and identifying key challenges that need to be addressed for successful integration of molecular imaging into the drug development process.
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Ma J, Waxman DJ. Modulation of the antitumor activity of metronomic cyclophosphamide by the angiogenesis inhibitor axitinib. Mol Cancer Ther 2008; 7:79-89. [PMID: 18202011 DOI: 10.1158/1535-7163.mct-07-0584] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The promising but still limited efficacy of angiogenesis inhibitors as monotherapies for cancer treatment indicates a need to integrate these agents into existing therapeutic regimens. Presently, we investigate the antitumor activity of the small-molecule angiogenesis inhibitor axitinib (AG-013736) and its potential for combination with metronomic cyclophosphamide. Axitinib significantly inhibited angiogenesis in rat 9L tumors grown s.c. in scid mice but only moderately delayed tumor growth. Combination of axitinib with metronomic cyclophosphamide fully blocked 9L tumor growth on initiation of drug treatment. In contrast, metronomic cyclophosphamide alone required multiple treatment cycles to halt tumor growth. However, in contrast to the substantial tumor regression that is ultimately induced by metronomic cyclophosphamide, the axitinib/cyclophosphamide combination was tumor growth static. Axitinib did not inhibit hepatic activation of cyclophosphamide or export of its activated metabolite, 4-hydroxy-cyclophosphamide (4-OH-CPA), to extrahepatic tissues; rather, axitinib selectively decreased 9L tumor uptake of 4-OH-CPA by 30% to 40%. The reduced tumor penetration of 4-OH-CPA was associated with a decrease in cyclophosphamide-induced tumor cell apoptosis and a block in the induction of the endogenous angiogenesis inhibitor thrombospondin-1 in tumor-associated host cells, which may contribute to the absence of tumor regression with the axitinib/cyclophosphamide combination. Finally, axitinib transiently increased 9L tumor cell apoptosis, indicating that its effects are not limited to the endothelial cell population. These findings highlight the multiple effects that may characterize antiangiogenic agent/metronomic chemotherapy combinations and suggest that careful optimization of drug scheduling and dosages will be required to maximize antitumor responses.
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Affiliation(s)
- Jie Ma
- Division of Cell and Molecular Biology, Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
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Prediction of antiangiogenic treatment efficacy by iron oxide enhanced parametric magnetic resonance imaging. Invest Radiol 2008; 42:791-6. [PMID: 18007150 DOI: 10.1097/rli.0b013e3180d5cbd9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE AND OBJECTIVES Tools for monitoring modern target-specific antiangiogenic and antivascular therapies are highly desirable because treatment strategies are time consuming, expensive, and yet sometimes ineffective. Therefore, the aim of this experimental study was to evaluate the predictive value of steady-state ultrasmall particles of iron oxide (USPIO; SH U 555 C)-enhanced magnetic resonance imaging (MRI) for early assessment of antivascular tumor-treatment effectiveness. METHODS Mice were inoculated with an HT-1080 fibrosarcoma xenograft and subjected to target-specific antivascular therapy using a selective thrombogenic vascular-targeting agent (truncated tissue factor fused to RGD peptide) or saline as control. Four to 8 hours after treatment, the USPIO-induced change in the transverse relaxation rate DeltaR2* was measured by MRI, and the vascular volume fraction (VVF) was calculated by calibrating DeltaR2* of the tumor by DeltaR2* of muscle tissue. Treatment response was defined by histologic grading of vascular thrombosis and tumor necrosis. RESULTS After thrombogenic treatment, half of the HT-1080 xenograft-bearing animals showed only minor (=nonresponder) whereas the other half showed extensive tumor thrombosis (=responders). For responders, a significant decrease of DeltaR2* and VVF was observed compared with the control group (DeltaR2*: controls: 16 +/- 1 s-1 vs. responder: 4 +/- 2 s-1; P < 0.001) whereas DeltaR2* and VVF remained nearly unchanged for nonresponders (DeltaR2*: nonresponder 14 +/- 2 s-1). VVF and DeltaR2* values correlated inversely with the histologic grading of vascular thrombosis and tumor necrosis (VVF: r = -0.8; DeltaR2*: r = -0.71; P < 0.01). CONCLUSION USPIO-enhanced MRI allows a noninvasive, early assessment of treatment efficacy of thrombogenic vascular-targeting agents.
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Medarova Z, Castillo G, Dai G, Bolotin E, Bogdanov A, Moore A. Noninvasive magnetic resonance imaging of microvascular changes in type 1 diabetes. Diabetes 2007; 56:2677-82. [PMID: 17682091 DOI: 10.2337/db07-0822] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE The pathogenesis of type 1 diabetes involves autoimmune lymphocytic destruction of insulin-producing beta-cells and metabolic dysregulation. An early biomarker of pancreatic islet damage is islet microvascular dysfunction, and alterations in vascular volume, flow, and permeability have been reported in numerous models of type 1 diabetes. Consequently, the ability to noninvasively monitor the dynamics of the pancreatic microvasculature would aid in early diagnosis and permit the assessment, design, and optimization of individualized therapeutic intervention strategies. RESEARCH DESIGN AND METHODS Here, we used the long circulating paramagnetic contrast agent, protected graft copolymer (PGC) covalently linked to gadolinium-diethylenetriaminepentaacetic acid residues (GdDTPAs) labeled with fluorescein isothiocyanate (PGC-GdDTPA-F), for the noninvasive semiquantitative evaluation of vascular changes in a streptozotocin (STZ)-induced mouse model of type 1 diabetes. Diabetic animals and nondiabetic controls were monitored by magnetic resonance imaging (MRI) after injection of PGC-GdDTPA-F. RESULTS Our findings demonstrated a significantly greater accumulation of PGC-GdDTPA-F in the pancreata of diabetic animals compared with controls. MRI permitted the in vivo semiquantitative assessment and direct visualization of the differential distribution of PGC-GdDTPA-F in diabetic and control pancreata. Ex vivo histology revealed extensive distribution of PGC-GdDTPA-F within the vascular compartment of the pancreas, as well as considerable leakage of the probe into the islet interstitium. By contrast, in nondiabetic controls, PGC-GdDTPA-F was largely restricted to the pancreatic vasculature at the islet periphery. CONCLUSIONS Based on these observations, we conclude that in the STZ model of type 1 diabetes, changes in vascular volume and permeability associated with early stages of the disease can be monitored noninvasively and semiquantitatively by MRI.
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Affiliation(s)
- Zdravka Medarova
- Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital/Harvard Medical School, Room 2301, Bldg. 149, 13th St., Charlestown, MA 02129, USA
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Mahmood U, Upadhyay R. Current and Future Imaging Paradigms in Colorectal Cancer. SEMINARS IN COLON AND RECTAL SURGERY 2007; 18:132-138. [PMID: 18516215 DOI: 10.1053/j.scrs.2007.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Umar Mahmood
- Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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Sheth RA, Upadhyay R, Weissleder R, Mahmood U. Real-Time Multichannel Imaging Framework for Endoscopy, Catheters, and Fixed Geometry Intraoperative Systems. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Rahul A. Sheth
- From the Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Rabi Upadhyay
- From the Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Ralph Weissleder
- From the Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Umar Mahmood
- From the Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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Seshadri M, Spernyak JA, Maiery PG, Cheney RT, Mazurchuk R, Bellnier DA. Visualizing the acute effects of vascular-targeted therapy in vivo using intravital microscopy and magnetic resonance imaging: correlation with endothelial apoptosis, cytokine induction, and treatment outcome. Neoplasia 2007; 9:128-35. [PMID: 17356709 PMCID: PMC1813934 DOI: 10.1593/neo.06748] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 01/05/2007] [Accepted: 01/08/2007] [Indexed: 01/08/2023] Open
Abstract
The acute effects of the vascular-disrupting agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA) were investigated in vivo using intravital microscopy (IVM) and magnetic resonance imaging (MRI). Changes in vascular permeability and blood flow of syngeneic CT-26 murine colon adenocarcinomas were assessed at 4 and 24 hours after DMXAA treatment (30 mg/kg, i.p.) and correlated with induction of tumor necrosis factor-alpha (TNF-alpha), endothelial damage [CD31/terminal deoxynucleotidyl transferase (TdT)], and treatment outcome. Intravital imaging revealed a marked increase in vascular permeability 4 hours after treatment, consistent with increases in intratumoral mRNA and protein levels of TNF-alpha. Parallel contrast-enhanced MRI studies showed a approximately 4-fold increase in longitudinal relaxation rates (DeltaR(1)), indicative of increased contrast agent accumulation within the tumor. Dual immunostained tumor sections (CD31/TdT) revealed evidence of endothelial apoptosis at this time point. Twenty-four hours after treatment, extensive hemorrhage and complete disruption of vascular architecture were observed with IVM, along with a significant reduction in DeltaR(1); and virtual absence of CD31 immunostaining. DMXAA-induced tumor vascular damage resulted in significant long-term (60-day) cures compared to untreated controls. Multimodality imaging approaches are useful in visualizing the effects of antivascular therapy in vivo. Such approaches allow cross validation and correlation of findings with underlying molecular changes contributing to treatment outcome.
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MESH Headings
- Adenocarcinoma/blood supply
- Adenocarcinoma/drug therapy
- Adenocarcinoma/pathology
- Animals
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Apoptosis/drug effects
- Capillary Permeability/drug effects
- Colonic Neoplasms/blood supply
- Colonic Neoplasms/drug therapy
- Colonic Neoplasms/pathology
- Contrast Media
- Drug Delivery Systems
- Drug Screening Assays, Antitumor
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/ultrastructure
- Female
- Hemorrhage/chemically induced
- Magnetic Resonance Imaging/methods
- Mice
- Mice, Inbred BALB C
- Microscopy/methods
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Transplantation/methods
- Pentetic Acid/analogs & derivatives
- Polylysine/analogs & derivatives
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Neoplasm/biosynthesis
- RNA, Neoplasm/genetics
- Skin Window Technique
- Transplantation, Heterotopic
- Transplantation, Isogeneic
- Tumor Necrosis Factor-alpha/biosynthesis
- Tumor Necrosis Factor-alpha/genetics
- Xanthones/pharmacology
- Xanthones/therapeutic use
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Affiliation(s)
- Mukund Seshadri
- Preclinical Imaging Resources, Department of Cancer Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Wang FE, Shi G, Niesman MR, Rewolinski DA, Miller SS. Receptor tyrosine kinase inhibitors AG013764 and AG013711 reduce choroidal neovascularization in rat eye. Exp Eye Res 2007; 84:922-33. [PMID: 17399700 PMCID: PMC1995411 DOI: 10.1016/j.exer.2007.01.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 12/18/2006] [Accepted: 01/15/2007] [Indexed: 12/27/2022]
Abstract
Age-related macular degeneration (AMD) is the major cause of blindness for people over 60. In the "wet" form of AMD compounds targeting growth factor signaling pathways such as VEGF have been a major focus for therapeutic interventions. In a previously developed rat model of CNV, we utilized two receptor tyrosine kinase inhibitors (RTKi) to block VEGFR-1, VEGFR-2 and PDGFR signaling following the establishment of CNV. AAV-VEGF(165) was injected into the subretinal space of rats at postnatal days 15-17. Six weeks later, a suspension of RTK inhibitors, AG013764 or AG013711, was injected intraperitoneally (IP, twice daily) or intravitreally (every five days) over a two week period. FITC-dextran whole-mounts of RPE-choroid-sclera were prepared after the animals were sacrificed. CNV area was quantified using Neurolucida to measure the hyperfluorescence on FITC-dextran whole-mounts. Histology and immunohistochemistry were performed as described previously. VEGF expression in control and treated eyes was confirmed by immunohistochemistry and histological sections indicated recovery of retinal morphology and CNV reduction in treated eyes. In the animals IP injected with AG013764 or AG013711 the mean CNV level was reduced by 25 to 33% compared to control, but this effect did not achieve statistical significance. Intravitreal injections of AG013764 or AG013711 reduced the level of CNV by approximately 60% compared to control (p<0.005 or p<0.05, respectively). These data show that two RTK inhibitors, AG013764 or AG013711, delivered intravitreally, significantly reduce blood vessel proliferation in this AAV-VEGF(165) model of CNV.
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Affiliation(s)
- F E Wang
- National Eye Institute, National Institutes of Health, 31 Center Drive, Building 31 Room 6A22, Bethesda, MD 20892, USA
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