Cellular therapies in ARDS

Acute respiratory distress syndrome (ARDS) is a critical illness characterized by a severe hypoxemic respiratory failure, caused by an inflammatory response which results in diffuse lung damage. Despite decades of research, the treatment of ARDS remains supportive. However, in recent years, cell-based therapies have been the subject of intensive ongoing research efforts, showing relevant therapeutic potential in preclinical ARDS models. Among all the different cells that have been identified as suitable candidates for use, mesenchymal stromal cells (MSCs) have been the most attractive candidates and have generated significant interest. MSCs are multipotent adult stem/stromal cells that can modulate the immune response and enhance repair of damaged tissue in multiple in vivo models. Their promising effect seems to be not primarily mediated by MSCs differentiation and engraftment but more by the paracrine release of different soluble mediators and cellular components such as extracellular vesicles (EVs). Preclinical experiments have provided encouraging evidence for the therapeutic potential of MSCs, leading to the launch of several phase I and II clinical trials that have shown safety of MSCs in ARDS, which became very common nowadays due to the Coronavirus disease (COVID-19) pandemic. However, some translational challenges have yet to be solved, such as the reproducibility of cell harvest, storage, reconstitution, and administration of cells/cell-products, before the therapeutic potential of stem cells therapies can be realized.