title: A new technique for the radiolabelling of mixed leukocytes with zirconium-89 for inflammation imaging with positron emission tomography.
abstract: Mixed leukocyte (white blood cells [WBCs]) trafficking using positron emission tomography (PET) is receiving growing interest to diagnose and monitor inflammatory conditions. PET, a high sensitivity molecular imaging technique, allows precise quantification of the signal produced from radiolabelled moieties. We have evaluated a new method for radiolabelling WBCs with either zirconium-89 ((89) Zr) or copper-64 ((64) Cu) for PET imaging. Chitosan nanoparticles (CNs) were produced by a process of ionotropic gelation and used to deliver radiometals into WBCs. Experiments were carried out using mixed WBCs freshly isolated from whole human blood. WBCs radiolabelling efficiency was higher with [(89) Zr]-loaded CN (76.8 ± 9.6% (n = 12)) than with [(64) Cu]-loaded CN (26.3 ± 7.0 % (n = 7)). [(89) Zr]-WBCs showed an initial loss of 28.4 ± 5.8% (n = 2) of the radioactivity after 2 h. This loss was then followed by a plateau as (89) Zr remains stable in the cells. [(64) Cu]-WBCs showed a loss of 85 ± 6% (n = 3) of the radioactivity after 1 h, which increased to 96 ± 6% (n = 3) loss after 3 h. WBC labelling with [(89) Zr]-loaded CN showed a fast kinetic of leukocyte association, high labelling efficiency and a relatively good retention of the radioactivity. This method using (89) Zr has a potential application for PET imaging of inflammation.
authors.affiliation: Wolfson Molecular Imaging Centre, Manchester, UK.
authors.forename: M
authors.initials: M
authors.lastname: Fairclough
authors.affiliation: Wolfson Molecular Imaging Centre, Manchester, UK.
authors.forename: C
authors.initials: C
authors.lastname: Prenant
authors.affiliation: NHS Foundation Trust, Central Manchester University Hospital, Manchester, UK.
authors.forename: B
authors.initials: B
authors.lastname: Ellis
authors.affiliation: Wolfson Molecular Imaging Centre, Manchester, UK.
authors.forename: H
authors.initials: H
authors.lastname: Boutin
authors.affiliation: Wolfson Molecular Imaging Centre, Manchester, UK.
authors.forename: A
authors.initials: A
authors.lastname: McMahon
authors.affiliation: Wolfson Molecular Imaging Centre, Manchester, UK.
authors.forename: G
authors.initials: G
authors.lastname: Brown
authors.affiliation: Materials Science Building, University of Manchester, Manchester, UK.
authors.forename: P
authors.initials: P
authors.lastname: Locatelli
authors.affiliation: Clinical Sciences Building, Salford Royal NHS Foundation Trust, Manchester, UK.
authors.forename: A K P
authors.initials: AK
authors.lastname: Jones
mesh_terms: D048271:Chitosan / Q000737:chemistry; D003301:Copper Radioisotopes; D003676:Deferoxamine / Q000737:chemistry; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging; D007553:Isotope Labeling / Q000379:methods*; D007962:Leukocytes / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry; D049268:Positron-Emission Tomography; D011868:Radioisotopes; D015040:Zirconium
chemical_list: D003301:Copper Radioisotopes; D011868:Radioisotopes; D048271:Chitosan; D015040:Zirconium; D003676:Deferoxamine
keywords: Cu-64; PET; Zr-89; chitosan nanoparticles; inflammation imaging; white blood cell trafficking