Human Amniotic Epithelial Cell Transplantation Induces Markers of Alternative Macrophage Activation and Reduces Established Hepatic Fibrosis

Abstract

Chronic hepatic inflammation from multiple etiologies leads to a fibrogenic response that can progress to cirrhosis and liver failure. Transplantation of human amniotic epithelial cells (hAEC) from term delivered placenta has been shown to decrease mild to moderate hepatic fibrosis in a murine model. To model advanced human liver disease and assess the efficacy of hAEC therapy, we transplanted hAEC in mice with advanced hepatic fibrosis. Immunocompetent C57BL/6 mice were administered carbon tetrachloride (CCl 4 ) twice weekly resulting in bridging fibrosis by 12 weeks. hAEC (2×10 6 ) were infused via the tail vein at week 8 or weeks 8 and 10 (single and double dose, respectively). Human cells were detected in mouse liver four weeks after transplantation showing hAEC engraftment. CCl 4 treated mice receiving single or double hAEC doses showed a significant but similar decrease in liver fibrosis area associated with decreased activation of collagen-producing hepatic stellate cells and decreased hepatic protein levels of the pro-fibrogenic cytokine, transforming growth factor-beta1. CCl 4 administration caused hepatic T cell infiltration that decreased significantly following hAEC transplantation. Hepatic macrophages play a crucial role in both fibrogenesis and fibrosis resolution. Mice exposed to CCl 4 demonstrated increased numbers of hepatic macrophages compared to normal mice; the number of macrophages decreased significantly in CCl 4 treated mice given hAEC. These mice had significantly lower hepatic protein levels of the chemokine monocyte chemoattractant protein-1 than mice given CCl 4 alone. Alternatively activated M2 macrophages are associated with fibrosis resolution. CCl 4 treated mice given hAEC showed increased expression of genes associated with M2 macrophages including YM-1, IL-10 and CD206. We provide novel data showing that hAEC transplantation induces a wound healing M2 macrophage phenotype associated with reduction of established hepatic fibrosis that justifies further investigation of this potential cell-based therapy for advanced hepatic fibrosis.

Therapeutic Effect of Human Amniotic Membrane–Derived Cells on Experimental Arthritis and Other Inflammatory Disorders

“…This could be due to the previously described epithelial-to-mesenchymal cell transition that amniotic epithelial cells undergo after various passages in culture (37). Both in vitro and in vivo studies have demonstrated that cells from either the epithelial or mesenchymal layers exert immunomodulatory properties and ameliorate disease with inflammatory bases, including lung and liver fibrosis and EAE (15,19,(38)(39)(40)(41). Interestingly, an important percentage of the HAMCs used in our study expressed CD106 (vascular cell adhesion molecule 1), which identifies a subpopulation of mesenchymal stem cells with unique immunoregulatory properties in various tissues, especially in the placenta (42).…”

A Rational Strategy for the Use of Amniotic Epithelial Stem Cell Therapy for Liver Diseases

“…Despite the xenogeneic conditions (human-rat), the human amnion membrane patch modulated the severity and progression of fibrosis. Manuelpillai et al demonstrated that systemic hAEC transplantation improved carbon tetrachloride-induced mouse liver fibrosis [55,56]. The xenogeneic (human-mouse) cell transplantation induced a significant reduction of activated hepatic stellate cells in the host liver.…”

Amniotic Epithelial Cells: A New Tool to Combat Aging and Age-Related Diseases?

“…The mechanisms implicated in the immunosuppressive and immunomodulatory properties of AECs have been elucidated using various target cells of the innate and the adaptive immune systems. AECs inhibit alloreactive T-lymphocytes in a mixed lymphocyte reaction (Pianta et al, 2015) and they also foster the switch from T-helper (Th) 1 and Th17 lymphocytes, to Th2 and Treg (Pianta et al, 2015), and M1 to M2 macrophages (Manuelpillai et al, 2012) through the release of anti-inflammatory cytokines. AECs also block maturation of monocytes into dendritic cells (Magatti et al, 2009) and inhibit proliferation of activated peripheral blood mononuclear cells in vitro (Wolbank et al, 2007) partly through the secretion of anti-inflammatory cytokines (Kang J. W. et al, 2012).…”

“…Sustained hepatic inflammation is a key prerequisite for fibrogenesis and is characterized by an activation of fibrogenic hepatic stellate cells and macrophages, both of which being reverted by the treatment with AECs (Manuelpillai et al, 2012; Hodge et al, 2014). The anti-fibrotic activity of transplanted AECs is accompanied by a reduction in hepatic TNF-α, IL-6, and TGF-β levels, and an induction in IL-10 levels and metalloproteinase-2 activity (Manuelpillai et al, 2010).…”