Subcellular storage and release mode of the novel 18F-labeled sympathetic nerve PET tracer LMI1195

Xinyu Chen, Rudolf A. Werner, Constantin Lapa, Naoko Nose, Mitsuru Hirano, Mehrbod S. Javadi, Simon Robinson, Takahiro Higuchi

Research output: Contribution to journalArticle

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Abstract

Background: 18F-N-[3-bromo-4-(3-fluoro-propoxy)-benzyl]-guanidine (18F-LMI1195) is a new class of PET tracer designed for sympathetic nervous imaging of the heart. The favorable image quality with high and specific neural uptake has been previously demonstrated in animals and humans, but intracellular behavior is not yet fully understood. The aim of the present study is to verify whether it is taken up in storage vesicles and released in company with vesicle turnover. Results: Both vesicle-rich (PC12) and vesicle-poor (SK-N-SH) norepinephrine-expressing cell lines were used for in vitro tracer uptake studies. After 2 h of 18F-LMI1195 preloading into both cell lines, effects of stimulants for storage vesicle turnover (high concentration KCl (100 mM) or reserpine treatment) were measured at 10, 20, and 30 min. 131I-meta-iodobenzylguanidine (131I-MIBG) served as a reference. Both high concentration KCl and reserpine enhanced 18F-LMI1195 washout from PC12 cells, while tracer retention remained stable in the SK-N-SH cells. After 30 min of treatment, 18F-LMI1195 releasing index (percentage of tracer released from cells) from vesicle-rich PC12 cells achieved significant differences compared to cells without treatment condition. In contrast, such effect could not be observed using vesicle-poor SK-N-SH cell lines. Similar tracer kinetics after KCl or reserpine treatment were also observed using 131I-MIBG. In case of KCl exposure, Ca2+-free buffer with the calcium chelator, ethylenediaminetetracetic acid (EDTA), could suppress the tracer washout from PC12 cells. This finding is consistent with the tracer release being mediated by Ca2+ influx resulting from membrane depolarization. Conclusions: Analogous to 131I-MIBG, the current in vitro tracer uptake study confirmed that 18F-LMI1195 is also stored in vesicles in PC12 cells and released along with vesicle turnover. Understanding the basic kinetics of 18F-LMI1195 at a subcellular level is important for the design of clinical imaging protocols and imaging interpretation.

Original languageEnglish
Article number12
JournalEJNMMI Research
Volume8
DOIs
Publication statusPublished - Jan 1 2018
Externally publishedYes

Fingerprint

PC12 Cells
3-Iodobenzylguanidine
Reserpine
Cell Line
N-(3-bromo-4-(3-(18F)fluoro-propoxy)benzyl)guanidine
Therapeutics
Clinical Protocols
Norepinephrine
Buffers
Acids
Membranes
In Vitro Techniques

Keywords

  • F-LMI1195
  • Heart failure
  • Phaeochromocytoma
  • Positron emission tomography
  • Storage vesicle turnover
  • Sympathetic nervous system

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

Subcellular storage and release mode of the novel 18F-labeled sympathetic nerve PET tracer LMI1195. / Chen, Xinyu; Werner, Rudolf A.; Lapa, Constantin; Nose, Naoko; Hirano, Mitsuru; Javadi, Mehrbod S.; Robinson, Simon; Higuchi, Takahiro.

In: EJNMMI Research, Vol. 8, 12, 01.01.2018.

Research output: Contribution to journalArticle

Chen, Xinyu ; Werner, Rudolf A. ; Lapa, Constantin ; Nose, Naoko ; Hirano, Mitsuru ; Javadi, Mehrbod S. ; Robinson, Simon ; Higuchi, Takahiro. / Subcellular storage and release mode of the novel 18F-labeled sympathetic nerve PET tracer LMI1195. In: EJNMMI Research. 2018 ; Vol. 8.
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abstract = "Background: 18F-N-[3-bromo-4-(3-fluoro-propoxy)-benzyl]-guanidine (18F-LMI1195) is a new class of PET tracer designed for sympathetic nervous imaging of the heart. The favorable image quality with high and specific neural uptake has been previously demonstrated in animals and humans, but intracellular behavior is not yet fully understood. The aim of the present study is to verify whether it is taken up in storage vesicles and released in company with vesicle turnover. Results: Both vesicle-rich (PC12) and vesicle-poor (SK-N-SH) norepinephrine-expressing cell lines were used for in vitro tracer uptake studies. After 2 h of 18F-LMI1195 preloading into both cell lines, effects of stimulants for storage vesicle turnover (high concentration KCl (100 mM) or reserpine treatment) were measured at 10, 20, and 30 min. 131I-meta-iodobenzylguanidine (131I-MIBG) served as a reference. Both high concentration KCl and reserpine enhanced 18F-LMI1195 washout from PC12 cells, while tracer retention remained stable in the SK-N-SH cells. After 30 min of treatment, 18F-LMI1195 releasing index (percentage of tracer released from cells) from vesicle-rich PC12 cells achieved significant differences compared to cells without treatment condition. In contrast, such effect could not be observed using vesicle-poor SK-N-SH cell lines. Similar tracer kinetics after KCl or reserpine treatment were also observed using 131I-MIBG. In case of KCl exposure, Ca2+-free buffer with the calcium chelator, ethylenediaminetetracetic acid (EDTA), could suppress the tracer washout from PC12 cells. This finding is consistent with the tracer release being mediated by Ca2+ influx resulting from membrane depolarization. Conclusions: Analogous to 131I-MIBG, the current in vitro tracer uptake study confirmed that 18F-LMI1195 is also stored in vesicles in PC12 cells and released along with vesicle turnover. Understanding the basic kinetics of 18F-LMI1195 at a subcellular level is important for the design of clinical imaging protocols and imaging interpretation.",
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AU - Chen, Xinyu

AU - Werner, Rudolf A.

AU - Lapa, Constantin

AU - Nose, Naoko

AU - Hirano, Mitsuru

AU - Javadi, Mehrbod S.

AU - Robinson, Simon

AU - Higuchi, Takahiro

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Background: 18F-N-[3-bromo-4-(3-fluoro-propoxy)-benzyl]-guanidine (18F-LMI1195) is a new class of PET tracer designed for sympathetic nervous imaging of the heart. The favorable image quality with high and specific neural uptake has been previously demonstrated in animals and humans, but intracellular behavior is not yet fully understood. The aim of the present study is to verify whether it is taken up in storage vesicles and released in company with vesicle turnover. Results: Both vesicle-rich (PC12) and vesicle-poor (SK-N-SH) norepinephrine-expressing cell lines were used for in vitro tracer uptake studies. After 2 h of 18F-LMI1195 preloading into both cell lines, effects of stimulants for storage vesicle turnover (high concentration KCl (100 mM) or reserpine treatment) were measured at 10, 20, and 30 min. 131I-meta-iodobenzylguanidine (131I-MIBG) served as a reference. Both high concentration KCl and reserpine enhanced 18F-LMI1195 washout from PC12 cells, while tracer retention remained stable in the SK-N-SH cells. After 30 min of treatment, 18F-LMI1195 releasing index (percentage of tracer released from cells) from vesicle-rich PC12 cells achieved significant differences compared to cells without treatment condition. In contrast, such effect could not be observed using vesicle-poor SK-N-SH cell lines. Similar tracer kinetics after KCl or reserpine treatment were also observed using 131I-MIBG. In case of KCl exposure, Ca2+-free buffer with the calcium chelator, ethylenediaminetetracetic acid (EDTA), could suppress the tracer washout from PC12 cells. This finding is consistent with the tracer release being mediated by Ca2+ influx resulting from membrane depolarization. Conclusions: Analogous to 131I-MIBG, the current in vitro tracer uptake study confirmed that 18F-LMI1195 is also stored in vesicles in PC12 cells and released along with vesicle turnover. Understanding the basic kinetics of 18F-LMI1195 at a subcellular level is important for the design of clinical imaging protocols and imaging interpretation.

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KW - F-LMI1195

KW - Heart failure

KW - Phaeochromocytoma

KW - Positron emission tomography

KW - Storage vesicle turnover

KW - Sympathetic nervous system

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