Yuanxin Chen1, John A. Ronald2,
Elisenda Rodriguez3, John W. Chen3, Kem A. Rogers4,
Brian K. Rutt2
1Imaging Research Laboratories, Robarts
Research Institute, London, Ontario, Canada; 2Department of
Radiology, Stanford University, Stanford, CA, United States; 3Center
for Systems Biology and Department of Radiology, Massachusetts General
Hospital, Boston, United States; 4Department of Anatomy and Cell
Biology, University of Western Ontario, London, Ontario, Canada
Bis-5-hydroxytryptamide-diethylenetriamine-pentaacetate
gadolinium [bis-5HT-DTPA(Gd)] is a highly sensitive and specific magnetic
resonance reporter of myeloperoxidase (MPO) activity in vivo. In this study,
we measured water proton T1 nuclear magnetic relaxation dispersion (NMRD)
profiles for bis-5HT-DTPA(Gd) solutions and of the aortic specimen excised
from atherosclerotic rabbits 2 hours after injection of
bis-5HT-DTPA(Gd). When activated by
MPO, bis-5HT-DTPA(Gd) exhibits a significant relaxivity increase over the
entire range of magnetic fields up to 0.93 T. Similarly, the NMRD profiles of
atherosclerotic aorta showed increased relaxivity enhancement compared to
aortic specimen from control rabbits. This supports our in vivo MRI results
that bis-5HT-DTPA(Gd) targets of MPO and identifies active inflammation in
experimental atherosclerosis.