Human umbilical cord mesenchymal stromal cell-derived exosomes protect against MCD-induced NASH in a mouse model

Background and aims Human umbilical cord mesenchymal stem cells (hUC-MSCs) are increasingly being studied in clinical trials of end-stage liver disease because of their good tissue repair and anti-inflammatory effects. hUC-MSC exosomes are vesicles with spherical structures secreted by cells that produce them. The diameter of exosomes is much smaller than that of hUC-MSCs, suggesting that exosomes might be a novel and safer therapeutic product of mesenchymal stem cells. As exosomes have been suggested to have biochemical functions similar to those of hUC-MSCs, this study investigated the efficiency of hUC-MSC-derived exosomes in protecting against nonalcoholic steatohepatitis using an MCD-induced mouse model. Methods Human umbilical cord mesenchymal stem cell-derived exosomes were extracted and purified. The effect of these exosomes on disease progression in an MCD-induced nonalcoholic steatohepatitis mouse model was investigated. Results The results showed that UC-MSC exosomes intravenously transplanted into mice with MCD-induced NASH improved MCD-induced body weight loss and liver damage in a mouse model. Additionally, the inflammatory cytokines in liver tissue were reduced, which may be caused by exosome-induced macrophage anti-inflammatory phenotypes both in vitro and in vivo. In addition, UC-MSC exosomes reversed PPARα level in ox-LDL-treated hepatocytes in vitro and in NASH mouse liver, which had been downregulated. Conclusions UC-MSC exosomes alleviate MCD-induced NASH in mice by regulating the anti-inflammatory phenotype of macrophages and by reversing PPARα protein expression in liver cells, which holds great potential in NASH therapy.