A possible link between increased metabolic activity of fat tissue and aortic wall inflammation in subjects with COPD. A retrospective (18)F-FDG-PET/CT pilot study

BACKGROUND: Fat tissue, and particularly visceral fat, is known to play low grade systemic inflammation in COPD, and is likely to contribute to excess cardiovascular comorbidity in COPD. Therefore, we aimed to study 18FDG-PET-assessed inflammation of the aorta and the (visceral) fat, and its interrelations and differences in subjects with and without COPD. retrospectively identified 42 patients (71% male, 48% current smokers, 66.6 +/- 8.3 years, mean BMI 25.1 +/- 4.3 kg/m2), who underwent 18F-FDG- for suspected early stage bronchus carcinoma. COPD-diagnosis was based spirometry and defined as FEV1/FVC < lower limit of normal. Inflammatory of aortic and fat regions was defined as the average of obtained maximum target-to-background ratios (meanTBRmax). The TBR is the standardized value (SUV) normalized to 18F-FDG blood pool activity. RESULTS: Compared controls, patients with COPD (n = 19; 45%) had increased meanTBRmax of abdominal aorta (1.31 +/- 0.14 vs. 1.49 +/- 0.31; p = 0.02) and the visceral fat (0.28 +/- 0.09 vs. 0.38 +/- 0.18; p = 0.047), while activity of the abdominal subcutaneous fat failed to show statistically significant differences (0.21 +/- 0.09 vs. 0.24 +/- 0.09; p = 0.345). In patients, meanTBRmax of abdominal visceral fat was correlated with the abdominal aorta, independently of age and BMI (beta = 0.590, p = CONCLUSION: Metabolic activity of the abdominal aorta and visceral fat increased in COPD patients compared to peers. The degree of visceral fat metabolic activity is associated with aortic inflammation. More research is warranted concerning the role of visceral fat in the vascular comorbidity in COPD.