Stem cell therapy for COVID-19 and other respiratory diseases: Global trends of clinical trials

Figure 2 Respiratory diseases, types of stem cells, and administrative routes. A: Type of stem cells; B: Routes of delivery; C: Respiratory diseases. COVID-19: Coronavirus disease 2019; BPD: Bronchopulmonary dysplasia; COPD: Chronic obstructive pulmonary disease; ALI/ARDS: Acute lung injury/acute respiratory distress syndrome; PF: Pulmonary fibrosis; PAH: Pulmonary arterial hypertension; UCB-MSCs: Umbilical cord blood derived-mesenchymal stem cells; BM-MSCs: Bone marrow-derived mesenchymal stem cells; AD-SCs: Adipose-derived stem cells; MSCs: Mesenchymal stem cells; EPCs: Endothelial progenitor cells; PB-SC: Peripheral blood stem cells; P-MSCs: Placental mesenchymal stem cells; MSC-EV: MSC-derived extracellular vesicles; BSCs: Bronchial stem cells; MB-SCs: Menstrual blood-derived stem cells; HMPC: Human heart muscle progenitor cells; LSCs: Lung stem cells; i.v.: Intravenous; i.t.: Intratracheal; i.n.: Intranasal; PA: Pulmonary artery; s.c.: Subcutaneous; NR: Not reported.