Figure 4.

Radiolabeled cationic ferritin (RadioCF)-positron emission tomography (PET) in healthy mice and in a mouse model of reduced nephron mass. A and B: healthy wild-type (WT) mice (n = 4) and mice with oligosyndactylism (Os^/+; n = 3), a model of reduced nephron mass, received RadioCF and were imaged with PET. Images were then overlain on computed tomography (CT). Only the cortex within the kidney was visible in both WT and Os^/+ mice. C and D: autoradiography showing 10% lower pixel-average intensity in Os^/+ kidney sections compared with controls. E: PET time-activity curves from the segmented kidney cortex were fitted to a biexponential model. WT mice exhibited a larger peak standardized uptake value (SUV) and SUV at 90 min compared with Os^/+ mice, consistent with the increase in average intensity per pixel in autoradiography images in WT mice. *Significant difference (P < 0.05, Student’s t test). SEs are reported (gray highlight). F: there was a significant difference in the percent injected dose (%ID)/organ between WT and Os^/+ mice from biodistribution studies using radiophosphorous imaging. SDs are shown. G: percent difference of peak SUV and SUV at 90 min was correlated with glomerular density (n = 4) calculated from stereology. MRI, magnetic resonance imaging; n, number of animals.