Safety, efficacy and biomarkers analysis of mesenchymal stromal cells therapy in ARDS: a systematic review and meta-analysis based on phase I and II RCTs

Background Mesenchymal stromal cells (MSCs) therapy for acute respiratory distress syndrome (ARDS) is an emerging treatment, but most of the current trials of MSCs stay in the animal experimental stage, and the safety and efficacy of MSCs in clinical application are not clear. We aimed to analyze the safety, efficacy and biomarkers of mesenchymal stromal cells in the treatment of ARDS. Methods For this systematic review and meta-analysis, we searched PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of science, CNKI, VIP and Wan Fang data, studies published between database inception and Mar 17, 2022. All randomized controlled trials (RCT) of stem cell interventions for ARDS were included, without language or date restrictions. We did separate meta-analyses for mortality, subjects with adverse events (AEs) and subjects with serious adverse events (SAEs). Since the trials data are dichotomous outcomes, the odds ratio (OR) is adopted for meta-analysis. The quality of the evidence was assessed with the Cochrane risk of bias tool. Findings In total, 5 trials involving 171 patients with ARDS were included in this meta-analysis. A total of 99 individuals were randomly assigned to receive MSCs treatment, and 72 were randomly assigned to receive placebo treatment. Treatment with MSCs appeared to increase the occurrence of adverse events, but this result was not statistically significant (OR, 1.58; 95%CI, 0.64-3.91; P = 0.32). The occurrence of serious adverse events was lower in the MSCs group than in the placebo group (OR, 0.57; 95%CI, 0.14-2.32; P = 0.43); there seems to be no significant difference between the two groups in terms of 28 days mortality (OR, 0.93; 95%CI, 0.45-1.89); oxygenation index and biomarkers showed a tendency to improve in treatment, but there was a lack of more statistically significant clinical evidence to support them. Interpretation Based on the current clinical trials, MSCs intervention has some safety for ARDS patients, but its effectiveness and predictive value of airspace biomarkers need to be determined by more large-scale, standard randomized controlled trials.