MSC-Based Cell Therapy for COVID-19-Associated ARDS and Classical ARDS: Comparative Perspectives

Despite no general conclusions regarding the therapeutic effect of MSCs on virus-induced acute lung injury in pre-clinical studies, a significant number of clinical trials using MSC-based treatment for COVID-19-associated ARDS were initiated during the global pandemic. Here, we aimed to discuss differences and similarities in clinical trials using MSC-based treatments for classical ARDS and COVID-19-associated ARDS and to raise some future perspectives. Several pre-clinical studies have demonstrated that MSC treatment may not be a good treatment option for virus infections because MSCs themselves are susceptible to the virus. However, MSCs lack expression of the angiotensin-converting enzyme 2 (ACE2) receptor, suggesting that MSCs are not likely to be infected by the COVID-19 virus. Interestingly, recent meta-analyses demonstrated that an improved survival rate in patients with COVID-19-associated ARDS treated with MSCs was obtained in 24 out of 26 completed clinical trials. This review provides comparative perspectives on MSC-based therapy for COVID-19-associated ARDS and classical ARDS.