ABSTRACT
Background: The COVID-19 has high transmission and mortality. Previous studies support the efficacy and safety of mesenchymal stem cells (MSCs) in the treatment of lung injury. In this study, We aimed to evaluate the CT changes of lung lesions in severe COVID-19 patients treated with umbilical cord mesenchymal stem cells (UC-MSCs) by using AI-assisted quantification method.Methods46 patients with severe COVID-19 from March 5 to April 1, 2020 were selected by single-blind, non-randomized controlled clinical study and divided into three groups: 11 cases in UC-MSCs treatment group 1 (MSC-1, with cells infusion once), 26 cases in UC-MSCs treatment group 2 (MSC-2, with cells infusion twice or three times), and 9 cases in control group with routine treatment. Repeated measure ANOVA was used to compare the effects of treatment factors on chest CT parameters of COVID-19 patients between control and experimental groups, and pairwise comparison using LSD test.FindingsThe differences between the percentage of GGO in total lung or the percentage of total lung infection volume on day 0 and that in day 60 as well as in day 90 were statistically significant among the three groups. The P values were 0.034 and 0.018 respectively. Pairwise comparison results showed that the percentage difference of the whole lung GGO and total lung infection volume in MSC-1 group was smaller than that in control group and MSC-2 group respectively, but there was no statistical difference between control group and MSC-2 group. The distribution characteristics and other CT parameters post-proceeded by AI software were not significantly different among the three groups. There were no serious adverse events related to stem cell infusion in all treated patients.InterpretationUC-MSC infusion is safe for the treatment of severe COVID-19 patients. The absorption of lung lesions at 60 days and 90 days after UC-MSC infusion once was more obvious than that in the control group. AI quantification of lung lesions is more suitable for comparative studies before and after treatment.