Bradley Hann1,2,
Kevin S. Tang3, Kevin M. Bennett2, Erik M. Shapiro,
3,4
1Biological Health System Engineering,
Arizona State College, Tempe, AZ, United States; 2School of
Biological and Health Systems Engineering, Arizona State University, Tempe,
AZ, United States; 3Department of Biomedical Engineering, Yale
University, New Haven, CT, United States; 4Department of
Diagnostic Radiology, Yale University School of Medicine, New Haven, CT,
United States
The
accumulation and presence of MPIOs in bone marrow was studied over seven
days. High-resolution, serial in-vivo MRI was performed on mice injected with
various quantities of MPIOs. MRI signal changes were monitored in bone marrow
and muscle to study MPIO trafficking. In vivo labeling efficiency of bone
marrow-resident monocytes was then quantified using flow cytometry.
Unexpected results were obtained. It was found that MPIOs did not label
monocytes in marrow. An alternative explanation for the success of MPIOs in
immune cell trafficking is presented, centered around re-entrance of MPIOs into
the circulation long after initial clearance from the vasculature.
Keywords