Publication Type	Academic Article
Authors	Anton M, Wittermann C, Haubner R, Simoes M, Reder S, Essien B, Wagner B, Henke J, Erhardt W, Noll S, Hackett N, Crystal R, Schwaiger M, Gansbacher B, Bengel F
Journal	J Nucl Med
Volume	45
Issue	10
Pagination	1743-6
Date Published	10/01/2004
ISSN	0161-5505
Keywords	Gene Transfer Techniques, Genetic Therapy, Muscle Cells, Thymidine Kinase, Vascular Endothelial Growth Factor A, Viral Proteins
Abstract	UNLABELLED: Coexpression of a reporter gene and a therapeutic gene may allow for noninvasive monitoring of cardiac gene therapy. We sought to evaluate the usefulness of an adenoviral vector expressing mutant herpesviral thymidine kinase reporter gene (HSV1-sr39tk) and vascular endothelial growth factor (VEGF) 121 in independent expression cassettes (Ad4tk). METHODS: Accumulation of 14C-2'-fluoro-5-methyl-1-beta-D-arabinofuranosyluracil (FIAU) and 9-(4-18F-fluoro-3-hydroxymethylbutyl)guanine (FHBG) as reporter probes, and secretion of VEGF into medium, were determined for Ad4tk-infected H9c2 rat cardiac cells in vitro. RESULTS: In vitro tracer uptake increased with increasing vector concentration and over time. It was comparable to cells infected with adenovirus expressing only wild-type HSV1-tk (reporter probe: 14C-FIAU) or mutant HSV1-sr39tk (reporter probe: 18F-FHBG). No significant uptake was observed in cells infected with adenovirus expressing VEGF alone. With increasing vector concentration, Ad4tk-infected cells increasingly released VEGF into medium. VEGF production correlated significantly with cellular reporter probe uptake (r = 0.93; P = 0.0003). CONCLUSION: The usefulness of a vector coexpressing HSV1-tk and VEGF for noninvasive imaging of expression of a therapeutic transgene has been demonstrated in vitro. This approach may allow for future in vivo monitoring of cardiac angiogenesis gene therapy.
PubMed ID	15471843