title: Scintigraphic imaging of experimental colitis with technetium-99m-infliximab in the rat.
abstract: The radiolabeled monoclonal antibody (99m)Tc-infliximab was assessed as an inflammation imaging agent in a rat colitis model in comparison with (99m)Tc-tin colloid-labeled-leucocytes. (99m)Tc-infliximab and (99m)Tc-tin fluoride colloid-labeled-leucocytes were administered to (n>3) rats previously exposed to 2,4,6-trinitrobenzenesulfonic acid by rectal instillation. Whole body scintigraphic images were acquired and physiological organ assays were performed to obtain quantitative data. Histological examination of colon samples was performed to assess the site and severity of the colitis. In the inflamed colon, (99m)Tc-infliximab resulted in inflamed target (T) to control (C) colon tracer uptake ratios of 2.7 +/- 1.0 (n=5) and 2.6 +/- 0.3 (n=5) at 1 and 4 h post tracer injection respectively. (99m)Tc-leucocytes gave higher ratios of 19.5 +/- 9.9 (n=3) and 41.2 +/- 16.1 (n=5) respectively. (99m)Tc-leucocytes gave higher ratios of 19.5 +/- 9.9 and 41.2 +/- 16.1 at the corresponding time points. (99m)Tc-infliximab accumulated at sites of inflammation in this rat model but not due to a specific tumor necrosis factor-alpha binding mechanism. Although the tracer uptake was lower than radioactive leucocytes, this easily prepared (99m)Tc-monoclonal antibody may have some advantages in imaging inflammatory bowel disease in humans based on its biological activity.
authors.affiliation: RAH Radiopharmacy, Nuclear Medicine Department, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000. ctsopela@mail.rah.sa.gov.au
authors.forename: Chris
authors.initials: C
authors.lastname: Tsopelas
authors.forename: Stan
authors.initials: S
authors.lastname: Penglis
authors.forename: Andrew
authors.initials: A
authors.lastname: Ruskiewicz
authors.forename: Dylan L
authors.initials: DL
authors.lastname: Bartholomeusz
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics*; D003092:Colitis / Q000000981:diagnostic imaging* / Q000378:metabolism*; D005240:Feasibility Studies; D000069285:Infliximab; D007962:Leukocytes / Q000000981:diagnostic imaging; D008657:Metabolic Clearance Rate; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013667:Technetium / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D019275:Radiopharmaceuticals; D013667:Technetium; D000069285:Infliximab