Micro-autoradiographic assessment of cell types contributing to 2-deoxy-2-[¹⁸f]fluoro-d-glucose uptake during ventilator-induced and endotoxemic lung injury

Purpose: The aim of the study was to use micro-autoradiography to investigate the lung cell types responsible for 2-deoxy-2-[¹⁸F] fluoro-d-glucose (FDG) uptake in murine models of acute lung injury (ALI). Procedures: C57/BL6 mice were studied in three groups: controls, ventilator-induced lung injury (VILI), and endotoxin. VILI was produced by high tidal volumes and zero end-expiratory pressure and endotoxin ALI, by intranasal administration. Following FDG injection, the lungs were processed and exposed to autoradiographic emulsion. Grain density over cells was used to quantify FDG uptake. Results: Neutrophils, macrophages, and type 2 epithelial cells presented higher grain densities during VILI and endotoxin ALI than controls. Remarkably, cell grain density in specific cell types was dependent on the injury mechanism. Whereas macrophages showed high grain densities during endotoxin ALI, similar to those exhibited by neutrophils, type 2 epithelial cells demonstrated the second highest grain density (with neutrophils as the highest) during VILI. Conclusions: In murine models of VILI and endotoxin ALI, FDG uptake occurs not only in neutrophils but also in macrophages and type 2 epithelial cells. FDG uptake by individual cell types depends on the mechanism underlying ALI.