Combination therapy of human umbilical cord mesenchymal stem cells and FTY720 attenuates acute lung injury induced by lipopolysaccharide in a murine model.

ALI/ARDS remain the main reason of morbidity and mortality in the critically ill. Studies have indicated that human umbilical cord mesenchymal stem cells (hUC-MSCs) can be useful in the treatment of ALI/ARDS. Sphingosine-1-phosphate (S1P) and its analog FTY720 significantly reduce lipopolysaccharide (LPS)-induced lung edema and inflammatory lung injury. This study aimed to assess the therapeutic effects of hUC-MSCs combined with FTY720 in an LPS-induced murine model of ALI. Eight-week-old female C57BL/6 mice were divided into a normal control group, an LPS group, an hUC-MSC group, an FTY720 group, and an hUC-MSCs+FTY720 group randomly. At 24 hours post injury, mice were administrated hUC-MSCs via the tail vein and/or intraperitoneally injected with FTY720. We assessed histopathology and histologic scores, lung wet/dry weight ratio, micro-CT scans, and total protein in the bronchoalveolar lavage fluid (BALF), as well as cytokines in the BALF at 48 h post injury. All treatment groups showed higher survival rates and attenuated lung injuries. The hUC-MSCs+FTY720 group yielded better results than hUC-MSCs or FTY720 alone. While the underlying mechanism requires further study, we anticipate that combination therapy of hUC-MSCs and FTY720 could be an effective strategy for ALI.