Background Pancreatic ductular adenocarcinoma (PDAC) is among the most dreadful of malignancies, in part due to the lack of efficacious chemotherapy. Immune checkpoint inhibitors, including anti-programmed cell death 1 (anti-PD-1) antibodies, are novel promising forms of systemic immunotherapy. In the current study, we assessed whether gemcitabine (GEM) combined with anti-PD-1 antibody treatment was efficacious as immunochemotherapy for advanced PDAC using a murine model of liver metastasis. Methods The murine model of PDAC liver metastasis was established by intrasplenically injecting the murine pancreatic cancer cell line PAN02 into immunocompetent C57BL/6J mice. The mice were treated with an anti-PD-1 antibody, GEM, or a combination of GEM plus anti-PD-1 antibody, and compared with no treatment (control); liver metastases, immune cell infiltration, gene expression, immune cell response phenotypes, and overall survival were investigated. Results In the metastatic tumor tissues of mice treated with GEM plus anti-PD-1 antibody, we observed the increased infiltration of Th1 lymphocytes and M1 macrophages. Gene expression profile analysis of peripheral blood cells obtained from mice treated with GEM plus anti-PD-1 antibody clearly highlighted T cell and innate immune signaling pathways. Survival of PDAC liver metastasis mice was significantly prolonged by the combination therapy (median survival, 66 days) when compared with that of GEM alone treatment (median survival, 56 days). Expanded lymphocytes, which were isolated from the splenocytes of PDAC liver metastasis mice treated with GEM plus anti-PD-1 antibody, had an increased number of M1 macrophages. Conclusion The combination of anti-PD-1 antibody immunotherapy with GEM was beneficial to treat a murine model of PDAC liver metastasis by enhancing the immune response mediated by Th1 lymphocytes and M1 macrophages and was associated with CD8+ T cells.

Cirrhosis is a chronic liver disease that impairs hepatic function and causes advanced fibrosis. Mesenchymal stem cells have gained recent popularity as a regenerative therapy since they possess immunomodulatory functions. We found that injected adipose tissue-derived stem cells (ADSCs) reside in the liver. Injection of ADSCs also restores albumin expression in hepatic parenchymal cells and ameliorates fibrosis in a nonalcoholic steatohepatitis model of cirrhosis in mice. Gene expression analysis of the liver identifies up- and down-regulation of genes, indicating regeneration/repair and anti-inflammatory processes following ADSC injection. ADSC treatment also decreases the number of intrahepatic infiltrating CD11b⁺ and Gr-1⁺ cells and reduces the ratio of CD8⁺/CD4⁺ cells in hepatic inflammatory cells. This is consistent with down-regulation of genes in hepatic inflammatory cells related to antigen presentation and helper T-cell activation. Conclusion: These results suggest that ADSC therapy is beneficial in cirrhosis, as it can repair and restore the function of the impaired liver. (Hepatology 2013;53:1133–1142)

Adipose tissue stromal cells contain a substantial number of mesenchymal stem cells. As such, their application to regeneration of miscellaneous impaired organs has attracted much attention. We designed a clinical study to investigate freshly isolated autologous adipose tissue-derived stromal/stem (regenerative) cell (ADRC) therapy for liver cirrhosis and conducted treatment in four cirrhotic patients. ADRCs were isolated from autologous subcutaneous adipose tissue obtained by the liposuction method, followed with use of the Celution system adipose tissue dissociation device. The primary endpoint is assessment of safety one month after treatment. We also characterized the obtained ADRCs. Two patients had type C cirrhosis, one had nonalcoholic steatohepatitis-cirrhosis, and one had type B cirrhosis. No serious adverse events were observed during the 1-month study period after freshly isolated ADRC infusion. Serum albumin concentrations were maintained or improved during this period as well as during the succeeding follow-up of approximately 1 year in two patients and 6 months in another patient. Liver regeneration-related factors, namely hepatocyte growth factor and interleukin-6, were elevated 1 day after ADRC treatment in all patients. The obtained freshly isolated ADRCs were expanded in culture and found to express mesenchymal stem cell markers. Gene expression profile analysis of ADRCs was shown to involve inflammatory features, suggesting that characteristics of the obtained ADRCs were related to immunomodulatory biological effects. This clinical study treatment for liver cirrhosis using ADRCs was proven to be safely conductible, and can be further investigated in future for regeneration/repair of liver cirrhosis.

Mesenchymal stromal stem cells (MSCs) are an attractive therapeutic model for regenerative medicine due to their pluripotency. MSCs are used as a treatment for several inflammatory diseases, including hepatitis. However, the detailed immunopathological impact of MSC treatment on liver disease, particularly for adipose tissue derived stromal stem cells (ADSCs), has not been described. Here, we investigated the immuno‐modulatory effect of ADSCs on hepatitis using an acute ConA C57BL/6 murine hepatitis model. i.v. administration of ADSCs simultaneously or 3 h post injection prevented and treated ConA‐induced hepatitis. Immunohistochemical analysis revealed higher numbers of CD11b⁺, Gr‐1⁺, and F4/80⁺ cells in the liver of ConA‐induced hepatitis mice was ameliorated after the administration of ADSCs. Hepatic expression of genes affected by ADSC administration indicated tissue regeneration‐related biological processes, affecting myeloid‐lineage immune‐mediating Gr‐1⁺ and CD11b⁺ cells. Pathway analysis of the genes expressed in ADSC‐treated hepatic inflammatory cells revealed the possible involvement of T cells and macrophages. TNF‐α and IFN‐γ expression was downregulated in hepatic CD4⁺ T cells isolated from hepatitis livers co‐cultured with ADSCs. Thus, the immunosuppressive effect of ADSCs in a C57BL/6 murine ConA hepatitis model was dependent primarily on the suppression of myeloid‐lineage cells and, in part, of CD4⁺ T cells.