Original ArticleIn vivo molecular imaging of myocardial angiogenesis using the αvβ3 integrin-targeted tracer 99mTc-RAFT-RGD
Section snippets
Synthesis
RAFT(cyclo[-RGDfK-])4 (RAFT-RGD) and the negative control RAFT(cyclo[-RADfK-])4 (RAFT-RAD) were synthesized as previously described.23
Labeling
125I labeling was performed by adding 20 to 50 μg of RAFT-RGD or RAFT-RAD to 10 μL of chloramin-T at 5 mg/mL (Amersham Pharmacia, Meylan, France) and ~18.5 MBq of 125I. After 20 minutes, the oxidation was stopped using 40 μL of sodium pyrosulfite (4 mg/mL). The radiochemical purity (RCP) was determined using thin-layer chromatography (TLC) using RP-18 TLC plates
In Vitro Experiments
The results are presented in Figure 1. There was a significant 3.3-fold higher radiolabeled RAFT-RGD uptake on HMVECs when compared to that of RAFT-RAD at all concentrations tested (Figure 1a). In addition, competition experiments indicated that radiolabeled RAFT-RGD uptake was inhibited by 60% in the presence of a 200-fold excess of unlabeled cRGD (Figure 1b).
CD31, αVβ3, and KiM2R Immunostaining
Results from CD31, αVβ3, and KiM2R immunostaining are presented in Figure 2. Endothelial CD31 expression was observed in the normal as
Discussion
The clinical importance of non-invasive angiogenesis assessment was recently emphasized in a pilot imaging study on patients.26 In the present study, experimental myocardial ischemia resulted in the induction of angiogenesis in the infarcted and peri-infarct zones at day 14 following reperfusion as previously described by others27 and as demonstrated by positive CD31 and αVβ3 immunostaining in the infarcted and peri-infarct zones. In addition to neovessels, macrophages are also known to express
Funding
Financial support was provided by the National Institute for Health and Medical Research (INSERM), the National Agency for Research and technology (ANRT), and ERAS Labo. The authors have no conflict of interest to disclose.
References (37)
- et al.
Macrophage colony-stimulating factor improves cardiac function after ischemic injury by inducing vascular endothelial growth factor production and survival of cardiomyocytes
Am J Pathol
(2007) - et al.
Inhibition of TGF-beta1 signaling by eNOS gene transfer improves ventricular remodeling after myocardial infarction through angiogenesis and reduction of apoptosis
Cardiovasc Pathol
(2007) - et al.
Therapeutic angiogenesis in chronically ischemic porcine myocardium: Comparative effects of bFGF and VEGF
Ann Thorac Surg
(2004) - et al.
Vascular endothelial growth factors: Biology and current status of clinical applications in cardiovascular medicine
J Am Coll Cardiol
(2007) Imaging of angiogenesis
J Nucl Cardiol
(2004)The RGD story: A personal account
Matrix Biol
(2003)- et al.
Cardiac remodeling by fibrous tissue after infarction in rats
J Lab Clin Med
(2000) - Cardiovascular Diseases. World Health Organization, fact sheet #317, 2007. Available at...
- et al.
Heart disease and stroke statistics—2010 update. A report from the American Heart Association
Circulation
(2009) - et al.
Left ventricular remodeling after myocardial infarction—pathophysiology and therapy
Circulation
(2000)