Abstract 3206: Quantitative Rage Imaging In Diabetic And Non-diabetic ApoE Null Mice
Receptors for Advanced Glycated Endproducts (RAGE) bind AGEs and other inflammatory ligands and are expressed in atherosclerotic plaques in diabetic and non-diabetic subjects. The higher expression in diabetes (DM) corresponds with accelerated course of the disease. This study was designed to test the hypothesis that the level of RAGE expression in atherosclerosis can be detected in-vivo by quantitative in-vivo SPECT imaging.
Methods and Results: A monoclonal murine antibody was developed against the V-domain of RAGE, fragmented into F(ab′)2 and labeled with 99mTc and dose of 402 ± 18 μCi or 14.8 ± 0.67 MBq injected into eleven 16 –24 week apoE−/− mice 5 with streptozotocin induced DM (given at 6 weeks). Four hours later (time based on blood pool clearance) mice were imaged on HiSPECT scanner (Bioscan), sacrificed, the proximal aorta removed, counted, and sectioned. Uptake in the thorax on SPECT corresponding to the proximal aorta was quantified as % ID using Interview XP (Mediso) software. For the total vascular area for each section, lesion size as % area and cells staining positive for RAGE as % total cells were quantified using immunohistomorphometry. Results expressed as mean values for the apoE−/− with and without DM are shown below. Lesion morphology was AHA class II-III and size ranged from 4 –56%. Values for % ID/g tissue and for % ID from scans for all mice were plotted against RAGE expression (% RAGE + cells) and the correlations were the following: % ID/g tissue vs. % RAGE + cells, R2 = 0.80, P = 0.0013, and for % ID scan vs. % RAGE + cells, R2 = 0.83, P = 0.0002.
Conclusions: In this pilot sample 99mTc-labeled anti-RAGE F(ab′)2 SPECT imaging successfully identified early accelerated atherosclerosis in diabetic apoE−/− mice compared to age matched non-diabetic apoE−/−mice and quantified RAGE expression over a range of lesion severities.
This research has received full or partial funding support from the American Heart Association, AHA Founders Affiliate (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Vermont).