Qin Z, Hoh CK, Olson ES, et al. - In this study, receptor-mediated binding of tilmanocept to CD206 within the kidney demonstrated and evidence of kinetic sensitivity of this binding to renal function was provided. Rats were administered an intravenous injection of ⁶⁸Ga-IRDye800-tilmanocept, using 1 of 2 scaled molar doses (0.02 nmol/g, n = 5; or 0.10 nmol/g, n = 5), or coinjection (n = 3) of ⁶⁸Ga-IRDye800-tilmanocept (0.10 nmol/g) and unlabeled tilmanocept (5.0 nmol/g), or a negative control, ⁶⁸Ga-IRDye800-DTPA-galactosyl-dextran (0.02 nmol/g, n = 5). Then researchers imaged each animal for 20 min that was followed by a whole-body scan. Receptor-mediated renal accumulation was identified in rat PET whole-body images and time–activity curves of ⁶⁸Ga-IRDye800-tilmanocept with evidence of glomerular uptake. During the 40-min study, they observed the persistence of the activity within the renal cortex. Colocalization of CD206 and IRDye800-tilmanocept within the glomerulus was identified with histologic examination. They observed significantly less glomerular accumulation of the coinjection and the negative control studies vs the CD206-targeted agent. Findings thereby indicate receptor-mediated binding to the glomerular mesangial cells and kinetic sensitivity of tilmanocept to chronic renal disease. As the progression of diabetic nephropathy involves mesangial cells, PET or SPECT renal imaging with radiolabeled tilmanocept seems to be valuable for making a noninvasive quantitative assessment of glomerular function.