Positron Emission Tomography Imaging of Cardiac Reporter Gene Expression in Living Rats

Wu, Joseph C.; Inubushi, Masayuki; Sundaresan, Gobalakrishnan; Schelbert, Heinrich R.; Gambhir, Sanjiv S.

doi:10.1161/01.cir.0000023620.59633.53

Cited by 142 publications

(105 citation statements)

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“…Recently, we demonstrated the feasibility of imaging the location, magnitude, and duration of a single PET (positron emission tomography) reporter gene (HSV1-sr39tk) expression in the myocardium of living rats using a dedicated small-animal microPET with high spatial resolution (2 mm 3 compared with 6 mm 3 for clinical PET). 10,11 We subsequently showed that the expression of 2 PET reporter genes (HSV1-sr39tk and mutant dopamine 2 receptor) linked together by an internal ribosomal entry site had good correlations in both cell assays (rϭ0.98, PϽ0.001) and rat myocardium (rϭ0.86, PϽ0.001). 12 Therefore, the present study is a logical progression of our previous works on cardiac gene imaging.…”

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confidence: 99%

Molecular Imaging of the Kinetics of Vascular Endothelial Growth Factor Gene Expression in Ischemic Myocardium

Chen

Wang

et al. 2004

Circulation

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Background— Angiogenic gene therapy is a promising treatment paradigm for patients with ischemic heart disease. In this study, we used micro-positron emission tomography (microPET) to monitor the transgene expression, function, and effects in a whole-body system. Methods and Results— Adenovirus with cytomegalovirus promoter driving an angiogenic gene (vascular endothelial growth factor [VEGF]) linked to a PET reporter gene (herpes simplex virus type 1 mutant thymidine kinase; Ad-CMV-VEGF 121 -CMV-HSV1-sr39tk) was used to transfect rat embryonic cardiomyoblasts in vitro. Expression of both genes correlated strongly ( r =0.98; P <0.001). Afterward, rats underwent ligation of the left anterior descending artery followed by injection of 1×10 10 pfu of Ad-CMV-VEGF 121 -CMV-HSV1-sr39tk (study; n=35) or Ad-null (control; n=15) at the peri-infarct region. Noninvasive microPET imaging was used to assess the uptake of 9-(4-[ 18 F]-fluoro-hydroxymethylbutyl)guanine ([ 18 F]-FHBG) PET reporter probe by cells expressing the HSV1-sr39tk PET reporter gene. Cardiac transgene expression peaked at day 1 and declined over the next 2 weeks. Repeat adenoviral injections at day 60 yielded no detectable signal. The in vivo reporter gene expression (% injected dose/g of [ 18 F]-FHBG) correlated well with ex vivo gamma counting ( r =0.92), myocardial tissue HSV1-sr39TK enzyme activity ( r =0.95), and myocardial tissue VEGF level ( r =0.94; P <0.001 for all). The VEGF 121 isoform induced significant increases in capillaries and small blood vessels. However, the level of neovasculature did not translate into significant improvements in functional parameters such as myocardial contractility by echocardiography, perfusion by nitrogen-13 ammonia imaging, and metabolism by [ 18 F]-fluorodeoxyglucose imaging. Conclusions— Taken together, these findings establish the feasibility of molecular imaging for monitoring angiogenic gene expression with a PET reporter gene and probe noninvasively, quantitatively, and repetitively. The principles demonstrated here can be used to evaluate other therapeutic genes of interest in animal models before future clinical trials are initiated.

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confidence: 99%

Molecular Imaging of the Kinetics of Vascular Endothelial Growth Factor Gene Expression in Ischemic Myocardium

Chen

Wang

et al. 2004

Circulation

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“…The former has been specifically validated for cardiac applications 10 ; we now report the first use of the latter system specifically for myocardial imaging. Compared with HSV1-sr39tk, D2R80a has the advantage of being endogenous and therefore should elicit minimal immune response and lead to prolonged adenovirus-mediated transgene expression in rat myocardium.…”

Section: Discussionmentioning

confidence: 99%

“…We have previously succeeded in monitoring adenovirus-mediated reporter gene expression in immunocompetent rats for Ϸ2 weeks, but not much longer because of the mounting of an intense host immune response. 10 To examine the behavior of Ad-CMVD2R80a-IRES-HSV1-sr39tk for a much longer period, we used athymic rats in this study to minimize immune response while simulating the case clinically when the subject is immunosuppressed. We then repeated experiments in immunocompetent rats to investigate whether host immune response would alter IRES-mediated translation or specifically the coupling between the expressions of HSV1-sr39tk and D2R80a.…”

Section: Discussionmentioning

confidence: 99%

“…15 Last, cardiac specific promoter (eg, cardiac myosin light chain 2), which can minimize hepatic expression after intramyocardial gene delivery, should be used in place of the constitutive CMV promoter to prevent potential side effects arising from injection-related viral leakage to the circulation. 10 Ultimately, with further refinement of the vector and improvement in PET quantification, the IRES-based bicistronic vector design should enable noninvasive imaging of the kinetics and biodistribution of therapeutic gene expression (eg, VEGF) in not only rat but also human myocardium.…”

Section: Discussionmentioning

confidence: 99%

“…10 Our goal in this study was to examine the use of an IRES-based bicistronic adenoviral vector (Ad-CMV-D2R80a-IRES-HSV1-sr39tk) for coupling the expression of 2 PET reporter genes ( Figure 1). The vector we specifically constructed contains a cytomegalovirus (CMV) early promoter driving the expression of 2 PET reporter genes, a mutant rat D2R (D2R80a) and a mutant HSV1-tk (HSV1-sr39tk), with the aid of an encephalomyocarditis virus (EMCV) IRES.…”

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Micro–Positron Emission Tomography Imaging of Cardiac Gene Expression in Rats Using Bicistronic Adenoviral Vector-Mediated Gene Delivery

Chen¹,

Wu²,

Min³

et al. 2004

Circulation

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Background-We have previously validated the use of micro-positron emission tomography (microPET) for monitoring the expression of a single PET reporter gene in rat myocardium. We now report the use of a bicistronic adenoviral vector (Ad-CMV-D2R80a-IRES-HSV1-sr39tk) for linking the expression of 2 PET reporter genes, a mutant rat dopamine type 2 receptor (D2R80a) and a mutant herpes simplex virus type 1 thymidine kinase (HSV1-sr39tk), with the aid of an internal ribosomal entry site (IRES). Methods and Results-Rat H9c2 cardiomyoblasts transduced with increasing titers of Ad-CMV-D2R80a-IRES-HSV1-sr39tk (0 to 2.5ϫ10 8 pfu) were assayed 48 hours later for reporter protein activities, which were found to correlate well with viral titer (r 2 ϭ0.96, PϽ0.001 for D2R80A; r 2 ϭ0.98, PϽ0.001 for HSV1-sr39TK) and each other (r 2 ϭ0.97; PϽ0.001). Experimental (nϭ8) and control (nϭ6) athymic rats underwent intramyocardial injection of up to 2ϫ10 9 pfu of Ad-CMV-D2R80a-IRES-HSV1-sr39tk and saline, respectively. Forty-eight hours later and weekly thereafter, rats were assessed for D2R80a-dependent myocardial accumulation of 3- (2- PϽ0.001). The location of adenovirus-mediated transgene expression, as inferred from microPET images, was confirmed by ex vivo gamma counting of explanted heart. Conclusions-The IRES-based bicistronic adenoviral vector can potentially be used in conjunction with PET for indirect imaging of therapeutic gene expression by replacing 1 of the 2 PET reporter genes with a therapeutic gene of choice.

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PET, SPECT, CT, and MRI in Mouse Cardiac Phenotyping: An Overview

et al. 2012

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This overview first summarizes the last decade of continuous developments and improvements in pre-clinical imaging methods that are now essential tools for in vivo evaluation of cardiac morphology and function in living mice, involving nuclear emission of labeled molecules (micro-PET and micro-SPECT) and electromagnetic wave interactions with biological tissues (micro-CT and micro-MRI). In the following, and for better understanding, the basic physical principles and specific technical innovations of the aforementioned imaging methods are reviewed. Specificity, sensitivity, and spatial and temporal resolutions, together with the corresponding advantages and weaknesses of each method are then discussed, and cardiac image-acquisition protocols and illustrative examples are given for each modality. Emerging hybrid cardiac imaging is also presented and illustrated. Then, recent biological insights provided by mouse cardiac imaging are presented. Finally, imaging strategies in mouse cardiac phenotyping involving the aforementioned methods, adding metabolic and molecular information to morphological data, are emphasized and discussed. Curr. Protoc. Mouse Biol. 2:129-144 © 2012 by John Wiley & Sons, Inc.

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Positron Emission Tomography Imaging of Cardiac Reporter Gene Expression in Living Rats

Cited by 142 publications

References 10 publications

Molecular Imaging of the Kinetics of Vascular Endothelial Growth Factor Gene Expression in Ischemic Myocardium

Molecular Imaging of the Kinetics of Vascular Endothelial Growth Factor Gene Expression in Ischemic Myocardium

Micro–Positron Emission Tomography Imaging of Cardiac Gene Expression in Rats Using Bicistronic Adenoviral Vector-Mediated Gene Delivery

PET, SPECT, CT, and MRI in Mouse Cardiac Phenotyping: An Overview

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