GFR-Vivo 680 Fluorescent Imaging Agent for Toxicology - Application note

Glomerular filtration rate (GFR) is the gold standard in kidney function assessment and is used to determine progression of kidney disease and drug-induced kidney toxicity. One of the most accepted ways to assess GFR is by measuring the rate of disappearance of labeled inulin from the blood; as inulin is completely filtered at the kidneys’ glomeruli (but neither secreted nor reabsorbed by the tubules), this rate of disappearance is directly proportional to GFR. We have developed a near infrared (NIR) fluorescent-labeled form of inulin (GFR-VivoTM 680) in a spectral region providing low background and high tissue penetration (ex/em = 670/685 nm) for in vivo application. Fluorescence molecular tomographic (FMT) imaging of the heart was used to detect and quantify blood levels of GFR-Vivo 680 at multiple time points, providing the necessary data to calculate the clearance rates in individual animals. Following an intravenous bolus of NIR-Inulin in SKH-1E mice, FMT® images were acquired at 1, 5, 15, 30, and 45 minutes post-injection. Clearance rates were calculated using a two-compartment curve fitting, yielding average rates of 270 + 6 mL/min in normal mice. GFR-Vivo 680, in combination with FMT heart imaging, provides a non-invasive fluorescent imaging approach to generate consistent GFR measurements in models of kidney disease, dysfunction, and drug toxicity. An in vivo non-invasive method to determine glomerular filtration rate (GFR) GFR-Vivo 680 Fluorescent Imaging Agent A P P L I C A T I O N N O T E