Smoking status and anti-inflammatory macrophages in bronchoalveolar lavage and induced sputum in COPD

Abstract

BackgroundMacrophages have been implicated in the pathogenesis of COPD. M1 and M2 macrophages constitute subpopulations displaying pro- and anti-inflammatory properties. We hypothesized that smoking cessation affects macrophage heterogeneity in the lung of patients with COPD. Our aim was to study macrophage heterogeneity using the M2-marker CD163 and selected pro- and anti-inflammatory mediators in bronchoalveolar lavage (BAL) fluid and induced sputum from current smokers and ex-smokers with COPD.Methods114 COPD patients (72 current smokers; 42 ex-smokers, median smoking cessation 3.5 years) were studied cross-sectionally and underwent sputum induction (M/F 99/15, age 62 ± 8 [mean ± SD] years, 42 (31-55) [median (range)] packyears, post-bronchodilator FEV1 63 ± 9% predicted, no steroids past 6 months). BAL was collected from 71 patients. CD163+ macrophages were quantified in BAL and sputum cytospins. Pro- and anti-inflammatory mediators were measured in BAL and sputum supernatants.ResultsEx-smokers with COPD had a higher percentage, but lower number of CD163+ macrophages in BAL than current smokers (83.5% and 68.0%, p = 0.04; 5.6 and 20.1 ×104/ml, p = 0.001 respectively). The percentage CD163+ M2 macrophages was higher in BAL compared to sputum (74.0% and 30.3%, p < 0.001). BAL M-CSF levels were higher in smokers than ex-smokers (571 pg/ml and 150 pg/ml, p = 0.001) and correlated with the number of CD163+ BAL macrophages (Rs = 0.38, p = 0.003). No significant differences were found between smokers and ex-smokers in the levels of pro-inflammatory (IL-6 and IL-8), and anti-inflammatory (elafin, and Secretory Leukocyte Protease Inhibitor [SLPI]) mediators in BAL and sputum.ConclusionsOur data suggest that smoking cessation partially changes the macrophage polarization in vivo in the periphery of the lung towards an anti-inflammatory phenotype, which is not accompanied by a decrease in inflammatory parameters.

Experimental progressive emphysema in BALB/cJ mice as a model for chronic alveolar destruction in humans

“…Consistent with previous studies, we found that the susceptible BALB/cJ mice had a very marked and prolonged production of MMP-12 in the lung in response to elastase injury than the resistant C57BL/6J strain. The polarization of macrophages toward an M2 phenotype accompanied by MMP-12 elevation has also been observed in the hookworm infection model of emphysema (51), an acute ozone exposure model (74), the mouse cigarette smoke model (24,92), and possibly in human emphysema patients (42). Interestingly, in addition to the expression of signature M2 markers such as arg1 and fizz1, we also found elevated expression of iNOS, a typical marker for classical activated macrophages (M1 phenotype) both at baseline and after elastase insult in the BALB/cJ strain.…”

Disruption of Sirtuin 1–Mediated Control of Circadian Molecular Clock and Inflammation in Chronic Obstructive Pulmonary Disease

“…Sputum was weighed and processed in a petri dish to remove plugs. Sputum samples were added with sputolysin reagent containing 0.1% dithiothreitol (Calbiochem, San Diego, CA) with volume of four times the weight of the selected sputum (4 ml:1 g sputum) to break the disulfide bonds in mucin molecules, allowing cells to be released through vortex (22). Cell-free supernatants of sputum were stored at 280 8 C. Cytospins were prepared with 60,000 to 120,000 cells per slides by centrifugation at 1,500 rpm for 5 minutes for immunofluorescent staining.…”

Identification of a distinct glucocorticosteroid-insensitive pulmonary macrophage phenotype in patients with chronic obstructive pulmonary disease

“…shown that active smoking in COPD reduced macrophage phagocytic ability, expression of CD163 and inferred a predominance of pro-inflammatory macrophages 15 . In the lung, the presence of different macrophage populations has been well known and sub-populations of Chana 6 macrophages have been identified on the basis of density using discontinuous Percoll gradients [16][17][18][19] .…”