5th EuropEan MolEcular IMagIng MEEtIng - ESMI

5th EuropEan MolEcular IMagIng MEEtIng – EMIM2010
Detection of inflammatory diseases by NIRF imaging with specific probes targeting
leukotriene receptor CysLT 1 R
Busch C. (1) , Passon M. (1) , Lehmann F. (2) , Socher I. (1) , Kaiser W.A. (1) , Hilger I. (1) .
(1) University Hospital Jena, IDIR, Jena, Germany
(2) DYOMICS GmbH, Jena, Germany
Corinna.Busch@med.uni-jena.de
Introduction: Leukotriene synthesis occurs early
in inflammatory processes and plays a major role
for the recruitment of leukocytes to the inflamed
region (1). A key representative of these eicosanoids,
leukotriene D4 (LTD4), shows high affinity
to G-protein coupled cysteinyl leukotriene
receptor 1 (CysLT 1 R). Detection of CysLT 1 R by
molecular imaging (2) with near-infrared (NIR)
fluorophores could be a suitable diagnostic tool
for early identification of inflammatory processes.
Aim of this study was the design and characterization
of NIRF-based contrast agents specifically
targeting CysLT 1 R in order to develop future diagnostic
tools for inflammatory diseases, particularly
in early stages.
Methods: Polyclonal rabbit CysLT 1 R antibody
(CysLT 1 R*DY-734) or polyclonal rabbit-IgG
(IgG*DY-734) as well as the corresponding Fab
fragments (Fab-CysLT 1 R*DY-734, Fab-IgG*DY-
734) were bound to activated NHS ester of NIRfluorophore
DY-734 (Dyomics, Jena, Germany).
Probes were characterized by determining dye/protein
ratios. After verification of CysLT 1 R expression
(PCR, flow cytometry) in HL-60 cells, binding
of the synthesized probes in vitro was assessed by
flow cytometry. In vivo, an ear edema was induced
in mice (3), and NIR fluorescence was measured
with whole body imaging system Maestro2.2 after
i.v.-probe administration. Ex vivo biodistribution
studies were performed.
Results: Flow cytometry proved binding of CysLT 1 R*DY-
734 and IgG*DY-734 to CysLT 1 R-expressing HL-60. In
vivo, all probes revealed stronger binding to the edematous
than to the corresponding healthy region. 6
h post injection, specific CysLT 1 R*DY-734 and Fab-
CysLT 1 R*DY-734 demonstrated 1.9 and 1.2 fold higher
binding than IgG*DY-734 and Fab-IgG*DY-734,
respectively. Investigation of isolated organs revealed
that full length IgG´s are eliminated via liver, while
Fab fragments additionally accumulated in kidney.
Conclusions: A novel NIRF-based probe specifically targeting
Leukotriene D 4 receptor CysLT 1 R allows detection
of inflammatory processes in ear edema-induced
mice in early stages.
Acknowledgement: The present investigations were
supported by the “Deutsche Forschungsgemeinschaft”
within the DFG program Hi 689/6-1.
References:
1. Hui Y, Funk C. Cysteinyl leukotriene receptors. Biochem.
Pharmacol. 2002;64:1549-57.
2. Weissleder R, Mahmood U. Molecular Imaging.
Radiology 2001;219:316-33.
3. Kurnatowska I, Pawlikowski M. Anti-inflammatory
effects of somatostatin analogs on zymosaninduced
earlobe inflammation in mice:
comparison with dexamethasone and ketoprofen.
Neuroimmunomodulation 2001;9:119-24.
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