PET imaging of inflammation and adenocarcinoma xenografts using vascular adhesion protein 1 targeting peptide 68Ga-DOTAVAP-P1: comparison with 18F-FDG.
OBJECTIVE
The aim of this study was to evaluate inflammation and tumour imaging with a vascular adhesion protein 1 (VAP-1) targeting peptide (68)Ga-DOTAVAP-P1 in comparison with (18)F-FDG.


METHODS
Rats with both subcutaneous human pancreatic adenocarcinoma xenografts and turpentine oil-induced acute sterile inflammation were evaluated by dynamic positron emission tomography (PET) and by digital autoradiography of tissue cryosections. Subsequently, the autoradiographs were combined with histological and immunohistological analysis of the sections.


RESULTS
(68)Ga-DOTAVAP-P1 delineated acute, sterile inflammation comparable with (18)F-FDG. However, the tumour uptake of (68)Ga-DOTAVAP-P1 was low in contrast to prominent (18)F-FDG uptake. The standardised uptake values of inflammation and tumours by PET were 1.1 +/- 0.4 (mean +/- SEM) and 0.4 +/- 0.1 for (68)Ga-DOTAVAP-P1 and 2.0 +/- 0.5 and 1.6 +/- 0.8 for (18)F-FDG, respectively. In addition, PET studies showed inflammation to muscle and tumour to muscle ratios of 5.1 +/- 3.1 and 1.7 +/- 0.3 for (68)Ga-DOTAVAP-P1 and 6.2 +/- 0.7 and 4.6 +/- 2.2 for (18)F-FDG, respectively. Immunohistochemistry revealed increased expression of luminal VAP-1 on the endothelium at the site of inflammation and low expression in the tumour


CONCLUSIONS
The (68)Ga-DOTAVAP-P1 PET was able to visualise inflammation better than tumour, which was in accordance with the luminal expression of VAP-1 on vasculature in these experimental models.
Turku PET Centre, University of Turku and Turku University Hospital, 20521 Turku, Finland.
Anu
A
Autio
Tiina
T
Ujula
Pauliina
P
Luoto
Satu
S
Salomäki
Sirpa
S
Jalkanen
Anne
A
Roivainen
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism*; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D019788:Fluorodeoxyglucose F18; D005710:Gallium Radioisotopes; D015972:Gene Expression Regulation, Neoplastic; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D049268:Positron-Emission Tomography; D051381:Rats; D012871:Skin Diseases / Q000000981:diagnostic imaging / Q000378:metabolism
D015815:Cell Adhesion Molecules; D005710:Gallium Radioisotopes; D006573:Heterocyclic Compounds, 1-Ring; D010455:Peptides; D019788:Fluorodeoxyglucose F18; C071349:1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid; C076668:AOC3 protein, human; D006631:Amine Oxidase (Copper-Containing)