Magnetically enriched bone marrow-derived macrophages loaded in vitro with iron oxide can migrate to inflammation sites in mice.
In vitro labelling of cells permits incorporation of large amounts of iron oxide and consequently high detection sensitivity, but it remains controversial whether labelled cells would respond normally to stimuli. This question was addressed by differentiating bone marrow-derived macrophages (BMDMs) in vitro, labelling cells with high concentrations of Endorem in vitro, and eliminating unlabelled cells by magnetic enrichment. To explore their acute inflammatory response, enriched cells were injected into mice with carrageenan-induced inflammation, the 'air pouch model'. Cells recovered from the inflammation site 16 h after intravenous BMDM injection into the tail vein were analysed by in vitro MRI and fluorescent microscopy. With both assays, Endorem-labelled cells were detectable. This indicates that BMDMs, loaded with high concentrations of iron oxide in vitro, can still respond to chemokine gradients and infiltrate inflamed tissue in mice. Furthermore, by using genetically modified mice as BMDM donors, it should be possible to study the role of individual genes in macrophage recruitment.
Hamm
Jörg
J
Department of Genetics, Biology and Biochemistry and CERMS, University of Turin, Turin, Italy. jorg_hamm@yahoo.com
Pulito
Roberta
R
Benedetto
Sabrina
S
Barberis
Laura
L
Hirsch
Emilio
E
Poli
Valeria
V
Silengo
Lorenzo
L
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism*; D002351:Carrageenan / Q000276:immunology; D002454:Cell Differentiation; D003911:Dextrans; D004195:Disease Models, Animal; D005290:Ferric Compounds / Q000009:adverse effects*; D052203:Ferrosoferric Oxide; D005549:Foreign-Body Reaction / Q000139:chemically induced*; D007501:Iron / Q000009:adverse effects; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000166:cytology / Q000276:immunology / Q000637:transplantation; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D010087:Oxides / Q000009:adverse effects; D012107:Research Design; D013535:Suspensions
D003911:Dextrans; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D010087:Oxides; D013535:Suspensions; C000499:ferric oxide; D002351:Carrageenan; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide