title: Uptake of radiolabeled 2'-fluoro-2'-deoxy-5-iodo-1-beta-D-arabinofuranosyluracil in cardiac cells after adenoviral transfer of the herpesvirus thymidine kinase gene: the cellular basis for cardiac gene imaging.
abstract: BACKGROUND
  Gene therapy is a promising approach for the treatment of cardiac diseases. Coexpression of therapeutic genes with a suitable marker gene would allow for the noninvasive imaging of successful gene transfer and expression via radiolabeled marker substrates. In the present study, such an approach was first applied to cardiac tissue.
  
  
  RESULTS
  The combination of the herpesvirus thymidine kinase reporter gene (HSV1-tk) and radiolabeled 2'-fluoro-2'-deoxy-5-iodo-1-beta-D-arabinofuranosyluracil (FIAU) was evaluated. H9c2 rat cardiomyoblasts were infected in vitro with a replication-defective HSV1-tk-containing adenovirus and a negative control virus. The intracellular uptake of [(14)C]FIAU increased with increasing multiplicity of infection and with time after infection. Uptake in negative controls remained <15% of positive controls. Additionally, vectors were applied intramyocardially in Wistar rats. The marker substrate [(125)I]FIAU was injected intravenously 3 days later, and animals were killed after 24 hours. Autoradiographically, regional transgene expression was clearly identified in animals receiving the adenovirus containing HSV1-tk (3. 4+/-2.2-fold increase of radioactivity at vector administration site compared with remote myocardium), whereas nonspecific uptake in negative controls was low (<10% of positive controls).
  
  
  CONCLUSIONS
  Using an adenoviral vector, HSV1-tk can be successfully expressed in cardiac cells in vitro and in vivo, yielding high uptake of radiolabeled FIAU. The results suggest that imaging transgene expression in the heart is feasible and may be used to monitor gene therapy noninvasively.
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Technische Universität München, Munich, Germany. frank.bengel@lrz.tu-muenchen.de
authors.forename: F M
authors.initials: FM
authors.lastname: Bengel
authors.forename: M
authors.initials: M
authors.lastname: Anton
authors.forename: N
authors.initials: N
authors.lastname: Avril
authors.forename: T
authors.initials: T
authors.lastname: Brill
authors.forename: N
authors.initials: N
authors.lastname: Nguyen
authors.forename: R
authors.initials: R
authors.lastname: Haubner
authors.forename: E
authors.initials: E
authors.lastname: Gleiter
authors.forename: B
authors.initials: B
authors.lastname: Gansbacher
authors.forename: M
authors.initials: M
authors.lastname: Schwaiger
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D001086:Arabinofuranosyluracil / Q000031:analogs & derivatives* / Q000494:pharmacology*; D001345:Autoradiography; D002250:Carbon Radioisotopes; D002460:Cell Line; D015870:Gene Expression; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D007275:Injections, Intravenous; D007457:Iodine Radioisotopes; D009206:Myocardium / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics; D013997:Time Factors
chemical_list: D002250:Carbon Radioisotopes; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D001086:Arabinofuranosyluracil; C043457:fialuridine; D013937:Thymidine Kinase