Human Umbilical Cord-Derived Mesenchymal Stem Cells for Acute Respiratory Distress Syndrome

Objectives: To investigate the safety, feasibility, and possible adverse events of single-dose human umbilical cord-derived mesenchymal stem cells in patients with moderate-to-severe acute respiratory distress syndrome. Design: Prospective phase I clinical trial. Setting: Medical center in Kaohsiung, Taiwan. Patients: Moderate-to-severe acute respiratory distress syndrome with a Pao₂/Fio₂ratio less than 200. Interventions: Scaling for doses was required by Taiwan Food and Drug Administration as follows: the first three patients received low-dose human umbilical cord-derived mesenchymal stem cells (1.0 × 10⁶cells/kg), the next three patients with intermediate dose (5.0 × 10⁶cells/kg), and the final three patients with high dose (1.0 × 10⁷cells/kg) between December 2017 and August 2019. Measurements and Main Results: Nine consecutive patients were enrolled into the study. In-hospital mortality was 33.3% (3/9), including two with recurrent septic shock and one with ventilator-induced severe pneumomediastinum and subcutaneous emphysema. No serious prespecified cell infusion-associated or treatment-related adverse events was identified in any patient. Serial flow-cytometric analyses of circulating inflammatory biomarkers (CD14⁺CD33⁺/CD11b+CD16+/CD16+MPO+/CD11b+MPO+/CD14^dimCD33+) and mesenchymal stem cell markers (CD26+CD45-/CD29+CD45-/CD34+CD45-/CD44+CD45-/CD73+CD45-/CD90+CD45-/CD105+CD45-/CD26+CD45-) were notably progressively reduced (p for trend < 0.001), whereas the immune cell markers (Helper-T-cell^CD3+CD4+/Cytotoxity-T-cell^CD3+CD8+/Regulatory-T-cell^{CD4+CD25+FOXp3+}) were notably increased (p for trend < 0.001) after cell infusion. Conclusions: The result of this phase I clinical trial showed that a single-dose IV infusion of human umbilical cord-derived mesenchymal stem cells was safe with favorable outcome in nine acute respiratory distress syndrome patients.