Effectiveness and safety profile of mesenchymal stem cell secretome as a treatment for severe cases of COVID-19: a randomized controlled trial

Abstract

Background: : Patients with severe COVID-19 had a higher increase in pro-inflammatory and anti-inflammatory cytokines than patients with moderate COVID-19. Excessive release of cytokine and chemokines can lead to multi-organ failure, increasing disease severity, length of stay, and mortality rate. Mesenchymal stem cells (MSCs) are known to have immunomodulatory, anti-inflammatory, anti-apoptotic, and angiogenesis effects that are useful for relieving inflammation, recovery, and protection of lung tissues in COVID-19 patients. Secretome, a secretory product of MSCs, has several advantages over MSCs. Therefore, we conducted a study to investigate secretomes' effectiveness and safety profile as a treatment for severe COVID-19. Methods: This study was a double-blind, multicentered, randomized, placebo-controlled trial. This study involved 40 subjects recruited from three top COVID-19 referral hospitals in the Greater Jakarta area, Indonesia. Eligible subjects (n=40) were randomized in a 1:1 ratio to intervention group (n=20) and a control group (n=20). The primary outcome of this study was the improvement of inflammatory markers levels, measured by changes in inflammatory markers, and ratio of inflammatory to anti-inflammatory markers. The secondary outcomes of this study included clinical outcome, laboratory outcome, radiological outcome, RT-PCR result conversion, and safety profile of MSC secretome. Results: IL-6 marker in the control group was increased on the 14 ^th day after the intervention compared to before intervention [4.110 (2.403-12.820) at baseline to 13.320 (2.958-33.285) on 14 ^th day after intervention, p=0.017]. In the intervention group, there was no increase in the IL-6/IL-10 ratio. In contrast, in the control group, there was a significant increase in the IL-6/IL-10 ratio (p=0.036) on the 14 ^th day after the intervention compared to before the intervention. We also found that on the seventh day after the intervention, most of the subjects who received placebo had high levels of IL-6 and ferritin (p=0.043). There was no significant difference in the laboratory outcome, radiological outcome, RT-PCR result conversion, and safety profile between both groups. Conclusions: Our study showed an increase of inflammation markers in the control group on the 14 ^th day after the intervention, compared to the intervention group. The ratio of inflammatory to anti-inflammatory markers on the seventh and 14 ^th days after intervention also did not increase in the intervention group. On the seventh day after intervention, most of the subjects in the control group also had high IL-6 levels and high ferritin levels. There is no adverse event reported. MSC secretome is a safe and promising treatment modality for severe COVID-19.

Keywords: COVID-19; cytokine; inflammation mediators; mesenchymal stem cell; secretome.

Figure 1.. Subject recruitment.

Figure 2.. Ratio of inflammation marker level for each time point.

Note that the ratios of inflammation markers on IL-6, IL-10, and VEGF in the control group tend to be more varied. The median ratio of IL-6 and VEGF also tend to be higher in the control group. There is no significant difference between both groups.

Figure 3.. Analyses of IL-6, IL-10, and Ferritin.

A) Ratio of IL-6/IL-10 on Day 0 (Before Intervention), the seventh day, and the 14 ^th day After Intervention. The IL-6/IL-10 ratio is increasing within 14 days after intervention in the control group. B) Relationship Between IL-6 and Ferritin on the seventh day After Intervention. Most of the subjects in the control group were distributed in the P-3 (high level of IL-6 and ferritin).

Figure 4.. Analyses of chest radiography parameters.

A) The proportions of lung lesion area before and after intervention in the intervention and control groups. Blue boxes represent proportions of lung lesion area before intervention, and res boxes represents proportions of lung lesion area after intervention. The median proportions of lung lesion area after intervention was decreased in both groups (deeper in intervention group), but not statistically significant. B) The chest radiography score (Brixia score) before and after intervention in the intervention and control groups. Blue boxes represent Brixia score before intervention and red boxes represents Brixia score after intervention. The median Brixia score after intervention was decreased in both groups (deeper in intervention group), but not statistically significant. C) The ratio of lung lesion area proportion and chest radiography score, after the intervention to before the intervention.