Introduction
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the novel coronavirus SARS-CoV-2. Common symptoms are mild including fever, cough, myalgia and difficulty breathing. Sputum production, diarrhea, sore throat and headache are less common. While most cases report a mild illness, in some cases, COVID-19 may affect the lungs causing pneumonia (Huang et al., 2020). In patients most severely affected, COVID-19 can be complicated by the acute respiratory distress syndrome (ARDS) or sepsis with acute organ dysfunction leading to significant morbidity, mortality and healthcare resource utilization (Huang et al., 2020, Wu and McGoogan, 2020).
ARDS is a life-threatening condition characterized by severe lung inflammation and reduced pulmonary gas exchange. Vascular endothelium and alveolar epithelium are damaged and alveolus is filled with protein-rich inflammatory edematous fluid. ARDS impairs the lungs’ ability to exchange oxygen and carbon dioxide resulting in hypoxia (Baudouin, 2004).
Coronavirus SARS-CoV-2 uses its surface glycosylated spike-protein (S-protein) to accesses type II alveolar cells of the lungs, which are the cells responsible for lung surfactant synthesis (Wan et al., 2020). In addition to the damage to type II alveolar cells, reductions in surfactant concentrations and functional alterations in surfactant composition have been described in ARDS (Raghavendran et al., 2011, Lewis and Veldhuizen, 2006).
Viral replication in COVID-19 activates the innate immune system to secrete various signaling proteins such as inflammatory cytokines, resulting in a cytokine storm and further lung damage (Mehta et al., 2020). This acute inflammation could also lead to heart failure, sepsis, and sudden cardiac arrest.
Polyethylene glycol (PEG) compounds are non-toxic, water soluble polymer with different molecular weight and numerous applications (Bejaoui et al., 2015). PEG has been used in vivo and in vitro in different model of tissue injury and it has shown many interesting biological properties; it has cytoprotective, anti-oxydant, immunosuppressive and anti-inflammatory effects (Lazar, 2015, Shi, 2013, Bejaoui et al., 2015, Bejaoui et al., 2016, Malhotra et al., 2011).
Here, we hypothesize that PEG alone or in combination with other agents could be an adjuvant treatment of COVID-19 patients with ARDS. Mechanisms may include immunocamouflage of cell membrane, enhancing surfactant protective properties, decreasing lung inflammation and protecting vascular endothelium and alveolar epithelium.