title: First preclinical evaluation of mono-[123I]iodohypericin as a necrosis-avid tracer agent.
abstract: OBJECTIVE
  We have labelled hypericin, a polyphenolic polycyclic quinone found in St. John's wort (Hypericum perforatum), with( 123)I and evaluated mono-[(123)I]iodohypericin (MIH) as a potential necrosis-avid diagnostic tracer agent.
  
  
  METHODS
  MIH was prepared by an electrophilic radioiodination method. The new tracer agent was evaluated in animal models of liver infarction in the rat and heart infarction in the rabbit using single-photon emission computed tomography (SPECT), triphenyltetrazolium chloride (TTC) histochemical staining, serial sectional autoradiography and microscopy, and radioactivity counting techniques.
  
  
  RESULTS
  Using in vivo SPECT imaging, hepatic and cardiac infarctions were persistently visualised as well-defined hot spots over 48 h. Preferential uptake of the tracer agent in necrotic tissue was confirmed by perfect match of images from post-mortem TTC staining, autoradiography (ARX) and histology. Radioactivity concentration in infarcted tissues was over 10 times (liver; 3.51% ID/g in necrotic tissue vs 0.38% ID/g in normal tissue at 60 h p.i.) and over 6 times (myocardium; 0.36% ID/g in necrotic tissue vs 0.054% ID/g in normal tissue; ratios up to 18 for selected parts on ARX images) higher than in normal tissues.
  
  
  CONCLUSIONS
  The results suggest that hypericin derivatives may serve as powerful necrosis-avid diagnostic agents for assessment of tissue viability.
authors.affiliation: Department of Radiology, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Yicheng
authors.initials: Y
authors.lastname: Ni
authors.forename: Dieter
authors.initials: D
authors.lastname: Huyghe
authors.forename: Kristin
authors.initials: K
authors.lastname: Verbeke
authors.forename: Peter A
authors.initials: PA
authors.lastname: de Witte
authors.forename: Johan
authors.initials: J
authors.lastname: Nuyts
authors.forename: Luc
authors.initials: L
authors.lastname: Mortelmans
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Guy
authors.initials: G
authors.lastname: Marchal
authors.forename: Alfons M
authors.initials: AM
authors.lastname: Verbruggen
authors.forename: Guy M
authors.initials: GM
authors.lastname: Bormans
mesh_terms: D000818:Animals; D000873:Anthracenes; D004353:Drug Evaluation, Preclinical; D006321:Heart / Q000000981:diagnostic imaging*; D008099:Liver / Q000000981:diagnostic imaging* / Q000473:pathology*; D008657:Metabolic Clearance Rate; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000378:metabolism; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis / Q000000981:diagnostic imaging; D010569:Perylene / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D010865:Pilot Projects; D011817:Rabbits; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
chemical_list: D000873:Anthracenes; D019275:Radiopharmaceuticals; D010569:Perylene; C004965:hypericin