Toll-Like Receptor 4 in Acute Respiratory Distress Syndrome: Good Time to Target?

Abstract

Acute respiratory distress syndrome (ARDS) is considered a major cause of death in the world. ARDS is defined by life-threatening pulmonary edema and hypoxemia with a mortality rate of up to 40%. Recent advances in understating cellular aspects of the syndrome have shed light on possible new treatments and reduction of mortality. Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) involved in adaptive and innate immunity. They are present in the alveoli and their activation can lead to inflammatory responses and finally acute lung injury. Among them, Toll-like receptor 4 (TLR4) is abundantly available on the epithelial cells of the alveoli and also on resident monocytes. TLR4 is one of the players that can promote alveolar damages during ARDS. Here, we focus on the TLR4 role in ARDS pathophysiology. We also present the potential therapies for the syndrome based on TLR4 inhibition.