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Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood–Brain Barrier
Author(s) -
Bauer M,
Römermann K,
Karch R,
Wulkersdorfer B,
Stanek J,
Philippe C,
MaierSalamon A,
Haslacher H,
Jungbauer C,
Wadsak W,
Jäger W,
Löscher W,
Hacker M,
Zeitlinger M,
Langer O
Publication year - 2016
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt.362
Subject(s) - abcg2 , pharmacology , verapamil , positron emission tomography , distribution (mathematics) , blood–brain barrier , medicine , chemistry , atp binding cassette transporter , transporter , nuclear medicine , biochemistry , gene , mathematics , central nervous system , mathematical analysis , calcium
ABCB1 and ABCG2 work together at the blood–brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([ 11 C]elacridar and [ 11 C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single‐nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high‐dose tariquidar. In contrast to the ABCB1‐selective substrate ( R )‐[ 11 C]verapamil, [ 11 C]elacridar and [ 11 C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [ 11 C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function.