Open AccessImaging grafted cells with [18F]FHBG using an optimized HSV1-TK mammalian expression vector in a brain injury rodent model
Author(s) -
AnneSophie Salabert,
Laurence Vaysse,
M. Beaurain,
Mathieu Alonso,
Germain Arribarat,
Jean-Albert Lotterie,
Isabelle Loubinoux,
Mathieu Tafani,
Pierre Payoux
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0184630
Subject(s) - in vivo , reporter gene , cell culture , in vitro , thymidine kinase , gliosarcoma , biomedical engineering , viability assay , microbiology and biotechnology , gene expression , nuclear medicine , chemistry , medicine , biology , gene , biochemistry , cancer research , glioma , genetics , virus , virology , herpes simplex virus
Cell transplantation is an innovative therapeutic approach after brain injury to compensate for tissue damage. To have real-time longitudinal monitoring of intracerebrally grafted cells, we explored the feasibility of a molecular imaging approach using thymidine kinase HSV1-TK gene encoding and [ 18 F]FHBG as a reporter probe to image enzyme expression. Methods A stable neuronal cell line expressing HSV1-TK was developed with an optimised mammalian expression vector to ensure long-term transgene expression. After [ 18 F]FHBG incubation under defined parameters, calibration ranges from 1 X 10 4 to 3 X 10 6 Neuro2A-TK cells were analysed by gamma counter or by PET-camera. In parallel, grafting with different quantities of [ 18 F]FHBG prelabelled Neuro2A-TK cells was carried out in a rat brain injury model induced by stereotaxic injection of malonate toxin. Image acquisition of the rats was then performed with PET/CT camera to study the [ 18 F]FHBG signal of transplanted cells in vivo . Results Under the optimised incubation conditions, [ 18 F]FHBG cell uptake rate was around 2.52%. In-vitro calibration range analysis shows a clear linear correlation between the number of cells and the signal intensity. The PET signal emitted into rat brain correlated well with the number of cells injected and the number of surviving grafted cells was recorded via the in-vitro calibration range. PET/CT acquisitions also allowed validation of the stereotaxic injection procedure. Technique sensitivity was evaluated under 5 X 10 4 grafted cells in vivo . No [ 18 F]FHBG or [ 18 F]metabolite release was observed showing a stable cell uptake even 2 h post-graft. Conclusion The development of this kind of approach will allow grafting to be controlled and ensure longitudinal follow-up of cell viability and biodistribution after intracerebral injection.