Multifaceted Therapeutic Benefits of Factors Derived From Dental Pulp Stem Cells for Mouse Liver Fibrosis

Chronic liver injury from various causes often results in liver fibrosis (LF). Although the liver possesses endogenous tissue-repairing activities, these can be overcome by sustained inflammation and excessive fibrotic scar formation. Advanced LF leads to irreversible cirrhosis and subsequent liver failure and/or hepatic cancer. Here, using the mouse carbon tetrachloride (CCl4)-induced LF model, we showed that a single intravenous administration of stem cells derived from human exfoliated deciduous teeth (SHEDs) or of SHED-derived serum-free conditioned medium (SHED-CM) resulted in fibrotic scar resolution. SHED-CM suppressed the gene expression of proinflammatory mediators, such as TNF-α, IL-1β, and iNOS, and eliminated activated hepatic stellate cells by inducing their apoptosis, but protected parenchymal hepatocytes from undergoing apoptosis. In addition, SHED-CM induced tissue-repairing macrophages that expressed high levels of the profibrinolytic factor, matrix metalloproteinase 13. Furthermore, SHED-CM suppressed the CCl4-induced apoptosis of primary cultured hepatocytes. SHED-CM contained a high level of hepatocyte growth factor (HGF). Notably, HGF-depleted SHED-CM (dHGF-CM) did not suppress the proinflammatory response or resolve fibrotic scarring. Furthermore, SHED-CM, but not dHGF-CM, inhibited CCl4-induced hepatocyte apoptosis. These results suggest that HGF plays a central role in the SHED-CM-mediated resolution of LF. Taken together, our findings suggest that SHED-CM provides multifaceted therapeutic benefits for the treatment of LF. Significance This study demonstrated that a single intravenous administration of stem cells from human exfoliated deciduous teeth (SHEDs) or of the serum-free conditioned medium (CM) derived from SHEDs markedly improved mouse liver fibrosis (LF). SHED-CM suppressed chronic inflammation, eliminated activated hepatic stellate cells by inducing their apoptosis, protected hepatocytes from undergoing apoptosis, and induced differentiation of tissue-repairing macrophages expressing high levels of the profibrinolytic factor matrix metalloproteinase 13. Furthermore, hepatocyte growth factor played a central role in the SHED-CM-mediated resolution of LF. This is the first report demonstrating the multifaceted therapeutic benefits of secreted factors derived from SHEDs for LF.