A new fluorescent imaging of renal inflammation with RCP.

The objective of this study is to design a fluorescent imaging agent with R-Gel, one of the recombinant polymers (RCP), for renal inflammation. The R-Gel based on human type I collagen has multiple Arg-Gly-Asp (RGD) motifs which are ligands for some types of integrin receptors on the cell surface. After intravenous administration of R-Gel labeled by Cy7 of a fluorescent dye to three animal models of nephritis mousse, interstitial nephritis (by using UUO model mice), glomerulonephritis (HIGA mice), and ischemia-reperfusion injured kidney (I/R mice), the extent of fluorescent imaging at the renal inflammation was assessed. The Cy7-labeled R-Gel was accumulated in the inflammation site to a significantly greater extent than in the normal one at 24h after administration. The renal pattern of fluorescent imaging was similar to that of administration anti-Mac1 antibody. Taken together, it is conceivable that the R-Gel was targeted to macrophages infiltrated into the inflammation site of kidney.