Micro-Autoradiographic Assessment of Cell Types Contributing to 2-Deoxy-2-[18F]Fluoro-d-Glucose Uptake During Ventilator-Induced and Endotoxemic Lung Injury

Abstract

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.

Quantification of Lung PET Images: Challenges and Opportunities

“…In a healthy volunteer model of endotoxin-induced acute lung inflammation, both K i and K iN increased, and both correlated weakly with neutrophil numbers (57). Other lung cells also likely contributed to increased 18 F-FDG uptake after endotoxin instillation, as shown in mouse models (58,59). These data demonstrate that increased 18 F-FDG uptake, quantified by both K i and K iN , are associated with neutrophilic inflammatory responses in these models.…”

Regional Lung Derecruitment and Inflammation during 16 Hours of Mechanical Ventilation in Supine Healthy Sheep

“…Another possibility is that the increase in 18 F-FDG uptake rate represents a broader proinflammatory effect caused by mild cyclical stretching of macrophages and epithelial cells. 48,49 It is tempting to hypothesize that such metabolic changes could be modified by interventions such as PEEP, recruitment maneuvers, and prone position. Indeed, a recent study showed improved lung function and reduced pulmonary infection scores when a protective ventilatory strategy predominantly based on PEEP = 10 versus 0 cmH 2 O was used intraoperatively during abdominal surgery.…”

Imaging Pulmonary Inflammation

“…The increased 18 F-FDG uptake in these activated cell types supports various functions related to their specific immune responses, including cytokine-induced activation of neutrophils and eosinophils (18,19), antigen receptor-mediated activation of lymphocytes (15,20), and polarization state changes in macrophages (21). Structural cells within the lungs also increase glucose utilization during inflammation (22,23). Therefore, increased lung 18 F-FDG uptake most likely represents a measure of the lungs' integrated inflammatory response in the context of lung inflammatory diseases.…”