Understanding the role of neutrophils in acute respiratory distress syndrome

Abstract

Acute respiratory distress syndrome (ARDS) is difficult to treat and is associated with a high mortality rate. The most severe form of coronavirus disease 2019 (COVID-19) also leads to life-threatening ARDS. Neutrophil counts are positively correlated with disease severity in ARDS. Neutrophil activation not only plays a significant role in immune defense against infections, but also causes tissue damage and leads to inflammatory diseases. Activated neutrophils rapidly migrate to inflamed lung tissue, releasing toxic granular contents and generating neutrophil extracellular traps. In the last few decades, it has become apparent that neutrophils occupy a central role in ARDS pathology. In this review, we summarize the neutrophil inflammatory responses and their relationships to ARDS. According to the current literature, understanding the function of neutrophils may be helpful in the treatment of ARDS.

The Role of Macrophages in the Development of Acute and Chronic Inflammatory Lung Diseases

“…Neutrophils and macrophages exert host defense against microbial invasion [ 8 , 11 ]. A neutrophil influx into the lungs is a hallmark of ALI/ARDS [ 15 ], and activated neutrophils cause inflammatory responses and tissue damage by producing toxic molecules and cytokines [ 16 ]. In the pathogenesis of ALI/ARDS, alveolar macrophages (AMs) are polarized into M1/M2 macrophages and participate in the exudative phase, rehabilitation phase, and, finally, the fibrotic phase ( Figure 2 ) [ 8 ].…”

Sterile Inflammation Alters Neutrophil Kinetics in Mice

“…Neutrophils play an essential role in pathogen and foreign body clearance(34). However, their aberrant activity may result in pathological conditions such as inflammatory bowel disease(35), rheumatoid arthritis(36), and acute respiratory distress syndrome(37). A potential strategy to enable their beneficial roles while also limiting their damaging effects is the modulation of neutrophil frequencies and life cycle(1, 13, 38).…”

Mesenchymal stem cell alongside exosomes as a novel cell-based therapy for COVID-19: A review study

“…Broncho alveolar fluid testing from COVID-19 patients recorded great levels of CXCL-8 and CXCL-2, chemokines that simplify the neutrophils recruitment to the infection zone [ 67 , 68 ], and extended activation of these phagocytic cells may lead to harmful effects in the respiratory system and cause ARDS [ 69 ]. In addition, neutrophils secrete toxic factors that might contribute to ARDS too [ 70 ]. Some of ROSs like H2O2 and superoxide radicals can produced follow a respiratory burst by neutrophil cells.…”