Sestrin 2 levels are associated with emphysematous phenotype of COPD.

Sestrins (Sesns) are a family of highly conserved stress-inducible proteins and various stresses have been shown to strongly up-regulate them. Sestrin 2 (Sesn2) deficiency has been shown to partially suppress pulmonary emphysema. The aim of this study was to evaluate Sesn2 levels in COPD patients and its possible associations with the presence of emphysema and blood eosinophils. All patients underwent lung function testing and high-resolution computed tomography (HRCT) of the chest. The presence of emphysematous lesions in >15% of the pulmonary parenchyma was considered as significant emphysema. Sixty-seven patients were included in the study. 40/67 patients were characterized as having significant emphysema. Patients with significant emphysema had higher levels of Sesn2 (ng/ml) [median (IQR) 6.7 (2.7,10.3 vs 1.09 (0.9,1.9), p<0.001)] and significantly lower % and absolute blood eosinophil counts (cells/µL) compared to patients without emphysema [1 (0, 2) vs 4 (2, 4) p<0.001 and 62 (0, 110) vs 248 (180, 300), p<0.001 respectively]. Sesn2 presented a significant positive correlation to the score of emphysema in HRCT (rs = 0.87, p<0.001) and similar positive but weaker correlation to FRC (rs = 0.27, p = 0.024). Negative correlations were observed between Sesn2 and either the % of blood eosinophils and/or the absolute blood eosinophil count (rs = -0.79, p<0.001, and rs = -0.78, p<0.001 respectively). Sesn2 levels above 1.87 ng/ml showed a high diagnostic performance for the presence of significant emphysema in HRCT with an AUC 0.93, 95% CI (0.85,0.98), p<0.001. Sesn2 could serve as a potential biomarker of emphysema.

Emphysematous Phenotype is Characterized by Low Blood Eosinophils: A Cross-Sectional Study.

Sputum and blood eosinophils are proposed as candidate biomarkers for the identification of chronic obstructive pulmonary disease (COPD) patients at risk for exacerbation and treatment response. In this study, we evaluated the associations of eosinophils with the presence of emphysema in COPD patients. Induced sputum and blood eosinophil measurements were performed in consecutive COPD patients. Patients underwent lung function testing and high resolution computed tomography (HRCT) of the chest and the presence of emphysema was quantified. Patients with emphysematous lesions in ≥15% of the pulmonary parenchyma were considered having significant emphysema. Ninety-eight patients were included in the study. Patients with significant emphysema had lower blood eosinophil counts compared to patients without emphysema [median (IQR) 34.6 (0.0, 63.0) vs. 169.0 (110.0, 260.0) cells/µL, p < 0.001]; similar results were observed for the percentage (%) of blood eosinophils, but no difference was observed for sputum eosinophils. The differences were evident in frequent and non-frequent exacerbators and irrespective of the use of inhaled corticosteroids (ICS). Patients with significant emphysema in HRCT present lower levels of blood eosinophils and these differences were present irrespective of the frequent exacerbator history or the use of ICS. Blood eosinophils may not represent a clinically relevant biomarker in the presence of emphysema.