MRI of the basement membrane using charged nanoparticles as contrast agents.
The integrity of the basement membrane is essential for tissue cellular growth and is often altered in disease. In this work a method for noninvasively detecting the structural integrity of the basement membrane, based on the delivery of cationic iron-oxide nanoparticles, was developed. Cationic particles accumulate due to the highly negative charge of proteoglycans in the basement membrane. The kidney was used to test this technique because of its highly fenestrated endothelia and well-established disease models to manipulate the basement membrane charge barrier. After systemic injection of cationic or native ferritin (CF or NF) in rats, ex vivo and in vivo MRI showed selective accumulation of CF, but not NF, causing a 60% reduction in signal intensity in cortex at the location of individual glomeruli. Immunofluorescence and electron microscopy demonstrated that this CF accumulation was localized to the glomerular basement membrane (GBM). In a model of GBM breakdown during focal and segmental glomerulosclerosis, MRI showed reduced single glomerular accumulation of CF, but a diffuse accumulation of CF in the kidney tubules caused by leakage of CF through the glomerulus. Cationic contrast agents can be used to target the basement membrane and detect the breakdown of the basement membrane in disease.
Bennett
Kevin M
KM
Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disease and Stroke, National Institutes of Health, Bethesda, Maryland, USA. kevin.m.bennett@asu.edu
Zhou
Hua
H
Sumner
James P
JP
Dodd
Stephen J
SJ
Bouraoud
Nadia
N
Doi
Kent
K
Star
Robert A
RA
Koretsky
Alan P
AP
D000818:Animals; D001485:Basement Membrane / Q000166:cytology* / Q000378:metabolism; D002412:Cations; D003287:Contrast Media / Q000378:metabolism*; D005293:Ferritins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D053758:Nanoparticles; D051381:Rats; D017207:Rats, Sprague-Dawley
D002412:Cations; D003287:Contrast Media; D005293:Ferritins