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Blocking of efflux transporters in rats improves translational validation of brain radioligands

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@article{828a001245cf4e38a1372aff8000bd9c,
title = "Blocking of efflux transporters in rats improves translational validation of brain radioligands",
abstract = "BACKGROUND: Positron emission tomography (PET) is a molecular imaging technique that can be used to investigate the in vivo pharmacology of drugs. Initial preclinical evaluation of PET tracers is often conducted in rodents due to the accessibility of disease models as well as economic considerations. Compared to larger species, rodents display a higher expression and/or activity of efflux transporters such as the P-glycoprotein (P-gp). Low brain uptake could, therefore, be species-specific and uptake in rodents not be predictive for that in humans. We hypothesized that a better prediction from rodent data could be achieved when a tracer is evaluated under P-gp inhibition. Consequently, we compared the performance of eight neuroreceptor tracers in rats with and without P-gp inhibition including a specific binding blockade. This data set was then used to predict the binding of these eight tracers in pigs.METHODS: PET tracers targeting serotonin 5-HT2A receptors ([18F]MH.MZ, [18F]Altanserin, [11C]Cimbi-36, [11C]Pimavanserin), serotonin 5-HT7 receptors ([11C]Cimbi-701, [11C]Cimbi-717 and [11C]BA-10) and dopamine D2/3 receptors ([18F]Fallypride) were used in the study. The brain uptake and target-specific binding of these PET radiotracers were evaluated in rats with and without inhibition of P-gp. Rat data were subsequently compared to the results obtained in pigs.RESULTS: Without P-gp inhibition, the amount of target-specific binding in the rat brain was sufficient to justify further translation for three out of eight evaluated tracers. With P-gp inhibition, results for five out of eight tracers justified further translation. The performance in pigs could correctly be predicted for six out of eight tracers when rat data obtained under P-gp inhibition were used, compared to four out of eight tracers without P-gp inhibition.CONCLUSIONS: P-gp strongly affects the uptake of PET tracers in rodents, but false prediction outcomes can be reduced by evaluating a tracer under P-gp inhibition.",
keywords = "Efflux transporter, P-gp, PET, Pigs, Rats, Rodents, Translation",
author = "Vladimir Shalgunov and Mengfei Xiong and L'Estrade, {Elina T} and Raval, {Nakul R} and Andersen, {Ida V} and Edgar, {Fraser G} and Speth, {Nikolaj R} and Baerentzen, {Simone L} and Hansen, {Hanne D} and Donovan, {Lene L} and Arafat Nasser and Peitersen, {Siv T} and Andreas Kjaer and Knudsen, {Gitte M} and Stina Syv{\"a}nen and Mikael Palner and Herth, {Matthias M}",
year = "2020",
month = oct,
day = "19",
doi = "10.1186/s13550-020-00718-x",
language = "English",
volume = "10",
pages = "124",
journal = "E J N M M I Research",
issn = "2191-219X",
publisher = "SpringerOpen",
number = "1",

}

RIS

TY - JOUR

T1 - Blocking of efflux transporters in rats improves translational validation of brain radioligands

AU - Shalgunov, Vladimir

AU - Xiong, Mengfei

AU - L'Estrade, Elina T

AU - Raval, Nakul R

AU - Andersen, Ida V

AU - Edgar, Fraser G

AU - Speth, Nikolaj R

AU - Baerentzen, Simone L

AU - Hansen, Hanne D

AU - Donovan, Lene L

AU - Nasser, Arafat

AU - Peitersen, Siv T

AU - Kjaer, Andreas

AU - Knudsen, Gitte M

AU - Syvänen, Stina

AU - Palner, Mikael

AU - Herth, Matthias M

PY - 2020/10/19

Y1 - 2020/10/19

N2 - BACKGROUND: Positron emission tomography (PET) is a molecular imaging technique that can be used to investigate the in vivo pharmacology of drugs. Initial preclinical evaluation of PET tracers is often conducted in rodents due to the accessibility of disease models as well as economic considerations. Compared to larger species, rodents display a higher expression and/or activity of efflux transporters such as the P-glycoprotein (P-gp). Low brain uptake could, therefore, be species-specific and uptake in rodents not be predictive for that in humans. We hypothesized that a better prediction from rodent data could be achieved when a tracer is evaluated under P-gp inhibition. Consequently, we compared the performance of eight neuroreceptor tracers in rats with and without P-gp inhibition including a specific binding blockade. This data set was then used to predict the binding of these eight tracers in pigs.METHODS: PET tracers targeting serotonin 5-HT2A receptors ([18F]MH.MZ, [18F]Altanserin, [11C]Cimbi-36, [11C]Pimavanserin), serotonin 5-HT7 receptors ([11C]Cimbi-701, [11C]Cimbi-717 and [11C]BA-10) and dopamine D2/3 receptors ([18F]Fallypride) were used in the study. The brain uptake and target-specific binding of these PET radiotracers were evaluated in rats with and without inhibition of P-gp. Rat data were subsequently compared to the results obtained in pigs.RESULTS: Without P-gp inhibition, the amount of target-specific binding in the rat brain was sufficient to justify further translation for three out of eight evaluated tracers. With P-gp inhibition, results for five out of eight tracers justified further translation. The performance in pigs could correctly be predicted for six out of eight tracers when rat data obtained under P-gp inhibition were used, compared to four out of eight tracers without P-gp inhibition.CONCLUSIONS: P-gp strongly affects the uptake of PET tracers in rodents, but false prediction outcomes can be reduced by evaluating a tracer under P-gp inhibition.

AB - BACKGROUND: Positron emission tomography (PET) is a molecular imaging technique that can be used to investigate the in vivo pharmacology of drugs. Initial preclinical evaluation of PET tracers is often conducted in rodents due to the accessibility of disease models as well as economic considerations. Compared to larger species, rodents display a higher expression and/or activity of efflux transporters such as the P-glycoprotein (P-gp). Low brain uptake could, therefore, be species-specific and uptake in rodents not be predictive for that in humans. We hypothesized that a better prediction from rodent data could be achieved when a tracer is evaluated under P-gp inhibition. Consequently, we compared the performance of eight neuroreceptor tracers in rats with and without P-gp inhibition including a specific binding blockade. This data set was then used to predict the binding of these eight tracers in pigs.METHODS: PET tracers targeting serotonin 5-HT2A receptors ([18F]MH.MZ, [18F]Altanserin, [11C]Cimbi-36, [11C]Pimavanserin), serotonin 5-HT7 receptors ([11C]Cimbi-701, [11C]Cimbi-717 and [11C]BA-10) and dopamine D2/3 receptors ([18F]Fallypride) were used in the study. The brain uptake and target-specific binding of these PET radiotracers were evaluated in rats with and without inhibition of P-gp. Rat data were subsequently compared to the results obtained in pigs.RESULTS: Without P-gp inhibition, the amount of target-specific binding in the rat brain was sufficient to justify further translation for three out of eight evaluated tracers. With P-gp inhibition, results for five out of eight tracers justified further translation. The performance in pigs could correctly be predicted for six out of eight tracers when rat data obtained under P-gp inhibition were used, compared to four out of eight tracers without P-gp inhibition.CONCLUSIONS: P-gp strongly affects the uptake of PET tracers in rodents, but false prediction outcomes can be reduced by evaluating a tracer under P-gp inhibition.

KW - Efflux transporter

KW - P-gp

KW - PET

KW - Pigs

KW - Rats

KW - Rodents

KW - Translation

UR - http://www.scopus.com/inward/record.url?scp=85092788306&partnerID=8YFLogxK

U2 - 10.1186/s13550-020-00718-x

DO - 10.1186/s13550-020-00718-x

M3 - Journal article

C2 - 33074370

VL - 10

SP - 124

JO - E J N M M I Research

JF - E J N M M I Research

SN - 2191-219X

IS - 1

M1 - 124

ER -

ID: 61117286