Inflammation: imaging with methoxy poly(ethylene glycol)-poly-L-lysine-DTPA, a long-circulating graft copolymer.
OBJECTIVE
To test whether a nontargeted, long-circulating, synthetic polymer accumulates in areas of inflammation, with high capillary permeability and increased regional blood flow.


METHODS
Methoxy poly(ethylene glycol)-poly-L-lysine (PL)-diethylenetriaminepentaacetic acid (MPEG-PL-DTPA) was labeled with technetium-99m for scintigraphy and with gadolinium for magnetic resonance (MR) imaging. Eleven Escherichia coli-infected rats were injected with 1.0 mCi (37 MBq) of Tc-99m-labeled MPEG-PL-DTPA for scintigraphy. Twelve rats underwent 1.5-T MR imaging after intravenous injection of gadolinium-labeled MPEG-PL-DTPA (35 mumol/kg).


RESULTS
Tc-99m-labeled MPEG-PL-DTPA demonstrated nearly eight-fold higher accumulation in infected muscle when compared with normal muscle. Scintigrams and MR images showed areas of inflammation with peak accumulation at 24 hours after injection of Tc-99m- or gadolinium-labeled MPEG-PL-DTPA.


CONCLUSIONS
Nontargeted, long-circulating, copolymers can efficiently accumulate in sites of inflammation and thus represent an alternative to inflammation-specific agents.
D000818:Animals; D002199:Capillary Permeability; D003287:Contrast Media / Q000493:pharmacokinetics; D004195:Disease Models, Animal; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D005240:Feasibility Studies; D005682:Gadolinium / Q000493:pharmacokinetics; D019786:Gadolinium DTPA; D007074:Immunoglobulin G; D007205:Indium Radioisotopes; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism / Q000382:microbiology; D004369:Pentetic Acid / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D011092:Polyethylene Glycols / Q000493:pharmacokinetics; D011107:Polylysine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D018461:Soft Tissue Infections / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics; D013848:Thigh; D013997:Time Factors
D003287:Contrast Media; D007074:Immunoglobulin G; D007205:Indium Radioisotopes; C081299:monomethoxypolyethylene glycol-polylysine-gadolinium DTPA; D011107:Polylysine; D011092:Polyethylene Glycols; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA; D016284:Technetium Tc 99m Pentetate