Multimodal optical and Gd-based nanoparticles for imaging in inflammatory arthritis.
OBJECTIVE
This report documents a multimodal nanoparticle (MNP) contrast agent, containing embedded luminophores and surface-immobilized gadolinium chelates, as a contrast agent of inflamed synovium in a collagen induced arthritis (CIA) model.


METHODS
DBA-1J mice were immunized for CIA and imaged after disease onset by two independent modalities. After intravenous administration of MNP contrast, optical and magnetic resonance images were obtained and clinical disease was scored, which was followed by processing of hindlimbs for immunofluorescence and confocal microscopy.


RESULTS
We show a correlation between disease severity and MNP optical luminescence that is dose dependent. Immunofluorescence of hindlimb sections reveal that MNP-labeled cells are monocytes/macrophages within the inflamed synovium. Magnetic resonance (MR) relaxation time maps, which determine the quantitative measure of T1 and T2 values at each imaging voxel, demonstrated a decreasing T2 signal in actively inflamed joints that was more pronounced earlier rather than later during disease.


CONCLUSIONS
MNPs containing surface-immobilized gadolinium chelates and embedded luminophores are potential dual-modality contrast agents in inflammatory arthritis and localize to monocytes/macrophages within inflamed synovium.
Kim
J S
JS
Department of Chemistry, Division of Rheumatology, Allergy, and Immunology, University of North Carolina School of Medicine, Chapel Hill, USA.
An
H
H
Rieter
W J
WJ
Esserman
D
D
Taylor-Pashow
K M L
KM
Sartor
R B
RB
Lin
W
W
Lin
W
W
Tarrant
T K
TK
D000818:Animals; D001169:Arthritis, Experimental / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media / Q000737:chemistry; D004487:Edema / Q000473:pathology; D005455:Fluorescent Antibody Technique; D005682:Gadolinium / Q000737:chemistry; D006614:Hindlimb / Q000187:drug effects / Q000473:pathology; D007275:Injections, Intravenous; D008264:Macrophages / Q000187:drug effects / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry; D051379:Mice; D008811:Mice, Inbred DBA; D018613:Microscopy, Confocal; D009000:Monocytes / Q000187:drug effects / Q000473:pathology; D013585:Synovitis / Q000139:chemically induced / Q000473:pathology
D003287:Contrast Media; D005682:Gadolinium