CURRENT CLINICAL TRIALS OF STEM CELL-BASED THERAPY IN COVID-19
Of late, stem-cell-based studies in the treatment of COVID-19 have been gaining momentum. The efficiency and safety of usage of exosomes that had been obtained from BM-MSCs was recently tested on 24 SARS-CoV-2 patients (46). These patients exhibited moderate to severe ARDS. When the exosomes were introduced into the patients, there were no side effects, and patients improved in clinical status and oxygenation (46). In a similar study, patients treated with MSCs showed a remark-able improvement in pulmonary function, higher levels of peripheral lymphocytes, and a reduction in the cells that trigger the cytokine storm. Interestingly, the MSCs did not exhibit ACE2 or TMPRSS2 expression, showing that they may not be infected with COVID-19 (47). Several clinical trials are in the pipeline for usage of stem cells for the treatment of COVID-19 (Table 2). Wharton’s jelly-derived MSCs (WJ-MSCs), which have been used in various studies based on stem-cell therapy and trials, are in progress for their usage for COVID-19 treatment (48). Moreover, adipose tissue-derived AD-MSCs have been used in a few studies in various doses and protocols for COVID-19 therapy (49). Likewise, a novel trial includes inhalation of MSC-Exos for alleviation of symptoms (50). In addition, MSCs from dental pulp (51) and olfactory mucosa (52) were administered in various doses. MSCs in the clinical trials are predominantly administered intravenously; i.v. injection and, in some studies, MSCs have been given as adjuvant therapy in addition to drugs like oseltamivir, hormones, hydroxychloroquine, and azithromycin (53, 54). These trials reveal promising new routes for the battle against COVID-19 (55-94).