Detection and quantification of endothelial VCAM‐1 expression using 19F magnetic resonance spectroscopy and imaging

Abstract

The early upregulation of vascular adhesion molecule‐1 (VCAM‐1) by the endothelium in disease states such as inflammation makes VCAM‐1 an attractive target for early detection of disease. The objective of this study was to develop a molecularly targeted perfluorocarbon nanoparticle (PFC‐NP) and quantify its binding to VCAM‐1 using fluorine spectroscopy. We have previously shown that VCAM‐1 expression is increased by the renal endothelium of apolipoprotein E deficient (ApoE −/−) mice fed a high cholesterol diet over control C57BL/6 mice. Liquid perfluorocarbon nanoparticle emulsions (PFC‐NP) targeted to VCAM‐1 were injected via the tail vein into ApoE−/− mice and allowed to circulate for 2h. Ex‐vivo kidney 19F imaging and spectroscopy was performed on an 11.7T Varian scanner. The fluorine signal was significantly higher in ApoE−/− kidneys treated with VCAM‐1 targeted PFC‐NP versus ApoE−/− kidneys injected with non‐targeted PFC‐NP (p < 0.01). Additionally, the kidneys of C57BL/6 control mice treated with VCAM‐1 targeted PFC‐NP had a fluorine signal significantly lower than VCAM‐1 targeted ApoE−/− signal (p < 0.05). These results suggest that changes in VCAM‐1 expression can be detected and quantified using 19F spectroscopy and that this technique may provide a non‐invasive method for early detection of inflammation. This work was supported by NIH grant #HL073646