Pro-inflammatory activity of COPD macrophages in the <i>in vitro</i> experiment

Abstract

Introduction. Chronic obstructive pulmonary disease (COPD) is a severe, progressive disease characterized by irreversible airway obstruction and emphysema. Prolonged exposition to airborne toxicants triggers irreversible processes leading to aberrant polarization of macrophages and defective phagocytosis, imbalance of pro- and anti-inflammatory cytokines. Aim. To study the features of the reaction of macrophages in COPD patients to the action of pro- and anti-inflammatory stimuli. Materials and methods. The study included 8 COPD patients and 6 control subjects. All persons underwent clinical and functional examination and sampling of peripheral venous blood for the isolation of monocytes. Cells had been cultured with 50 ng/mL granulocyte-macrophage colony-stimulating factor for 6 days, and then were polarized into pro-inflammatory (M1) and anti-inflammatory (M2) macrophages by adding E. coli lipopolysaccharides (LPS) 100 ng/mL and recombinant human interferon gamma (IFN-γ) 20 ng/ml, or interleukin 4 (IL-4) 20 ng/ml, respectively. Cytokine analysis was performed in the culture medium supernatant by multiplex analysis on a flow cytometer. Results. In the non-polarized state (M0), cells of COPD patients and the control group did not differ in the rate of cytokine production. At the same time, under LPS/IFN-γ stimulation a more pronounced increase in pro-inflammatory CXCL10 was observed in patients with COPD as compared with the control group (104.5-fold vs. 41.6-fold, p=0.04), and in the control group, on the contrary, the production of anti-inflammatory IL-10 was increased to a greater extent (99.6-fold vs. 30.5- fold, p=0.06). The effect of IL-4 on COPD macrophages was accompanied by a more pronounced decrease in IL-6, TNFα and IL-8 as compared to the group of healthy subjects. Conclusion. COPD macrophages are characterized by increased sensitivity to polarizing stimuli: under M1 stimulation we observed increased pro-inflammatory activity and under conditions of M2 differentiation, on the contrary, more pronounced inhibition of pro-inflammatory mediators occurred.