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Title
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In vivo evaluation of -4-(2-(bis(4-fluorophenyl)methoxy)ethyl)-1-(4-iodobenzyl)piperidine, an iodinated SPECT tracer for imaging the P-gp transporter
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Author
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Abstract
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| Introduction P-glycoprotein (P-gp) is an energy-dependent transporter that contributes to the efflux of a wide range of xenobiotics at the bloodbrain barrier playing a role in drug-resistance or therapy failure. In this study, we evaluated [123I]-4-(2-(bis(4-fluorophenyl)methoxy)ethyl)-1-(4-iodobenzyl)piperidine ([123I]-FMIP) as a novel single photon emission computed tomography (SPECT) tracer for imaging P-gp at the brain in vivo. Methods The tissue distribution and brain uptake as well as the metabolic profile of [123I]-FMIP in wild-type and mdr1a (−/−) mice after pretreatment with physiological saline or cyclosporin A (CsA) (50 mg/kg) was investigated. The influence of increasing doses CsA on brain uptake of [123I]-FMIP was explored. μSPECT images of mice brain after injection of 11.1 MBq [123I]-FMIP were obtained for different treatment strategies thereby using the Milabs U-SPECT-II. Results Modulation of P-gp with CsA (50 mg/kg) as well as mdr1a gene depletion resulted in significant increase in cerebral uptake of [123I]-FMIP with only minor effect on blood activity. [123I]-FMIP is relative stable in vivo with >80% intact [123I]-FMIP in brain at 60 min p.i. in the different treatment regiments. A dose-dependent sigmoidal increase in brain uptake of [123I]-FMIP with increasing doses of CsA was observed. In vivo region of interest-based SPECT measurements correlated well with the observations of the biodistribution studies. Conclusions These findings indicate that [123I]-FMIP can be applied to assess the efficacy of newly developed P-gp modulators. It is also suggested that [123I]-FMIP is a promising SPECT tracer for imaging P-gp at the blood-brain barrier. |
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Language
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English
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Source (journal)
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Nuclear geophysics. - Oxford, 1993, currens
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Publication
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Oxford
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2010
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ISSN
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0969-8086
[print]
1878-6383
[online]
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DOI
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10.1016/J.NUCMEDBIO.2009.10.006
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Volume/pages
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37
:4
(2010)
, p. 469-477
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ISI
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000277701900011
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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