Mesenchymal stem cells cultured under hypoxic conditions had a greater therapeutic effect on mice with liver cirrhosis compared to those cultured under normal oxygen conditions

Abstract

BackgroundMesenchymal stem cells (MSCs) can be easily expanded. They can be acquired from medical waste such as adipose and umbilical cord tissues, are influenced by culturing conditions, and exert anti-inflammatory, antioxidant, anti-fibrotic, and angiogenic effects. We analyzed the multi-directional effects of MSCs cultured under hypoxic conditions and their underlying mechanisms in the treatment of liver cirrhosis in a mouse model.MethodsHuman bone marrow-derived MSCs cultured under hypoxic (5% O2; hypoMSCs) and normoxic (21% O2; norMSCs) conditions were compared by cap analysis of gene expression (CAGE) with or without serum from liver cirrhosis patients. The therapeutic effects of MSCs, including serum liver enzyme induction, fibrosis regression, and hepatic oxidative stress, were evaluated by injecting 1 × 106, 2 × 105, or 4 × 104 MSCs/mouse into the tail veins of mice with carbon tetrachloride (CCl4)-induced liver cirrhosis. Intravital imaging was performed with a two-photon excitation microscope to confirm the various MSC migration paths to the liver.ResultsCAGE analysis revealed that the RNA expression levels of prostaglandin E synthase (Ptges) and miR210 were significantly higher in hypoMSCs than in norMSCs. In vivo analysis revealed that both hypoMSCs and norMSCs reduced serum alanine aminotransferase, oxidative stress, and fibrosis compared to that in control mice in a dose-dependent manner. However, hypoMSCs had stronger therapeutic effects than norMSCs. We confirmed this observation by an in vitro study in which hypoMSCs changed macrophage polarity to an anti-inflammatory phenotype via prostaglandin E2 (PGE2) stimulation. In addition, miR210 reduced the rate of hepatocyte apoptosis. Intravital imaging after MSC administration showed that both cell types were primarily trapped in the lungs. Relatively a few hypoMSCs and norMSCs migrated to the liver. There were no significant differences in their distributions.ConclusionThe therapeutic effect of hypoMSCs was mediated by PGE2 and miR210 production and was greater than that of norMSCs. Therefore, MSCs can be manipulated to improve their therapeutic efficacy in the treatment of liver cirrhosis and could potentially serve in effective cell therapy. MSCs produce several factors with multidirectional effects and function as “conducting cells” in liver cirrhosis.

Therapeutic Properties of Mesenchymal Stromal/Stem Cells: The Need of Cell Priming for Cell-Free Therapies in Regenerative Medicine

“…Furthermore, different studies are evaluating hypoxia as a priming strategy to improve MSC potential in fibrosis inhibition [ 136 ]. In particular, a recent work in a mouse model of liver fibrosis demonstrated that hypoxia-primed MSCs (H-MSCs) enhanced PGE2 expression [ 137 ]. They also showed increased levels of miR-210 in H-MSCs and this miRNA played different roles in fibrosis processes such as suppression of apoptosis, arrest of cell proliferation and repression of mitochondria respiration [ 137 ].…”

The Application of Mesenchymal Stem Cells in the Treatment of Liver Diseases: Mechanism, Efficacy, and Safety Issues

“…A hypoxic culture environment can contribute to the maintenance of MSC proliferation, differentiation and metabolic balance (113). According to Kojima et al, compared with those cultured in normal conditions, BM-MSCs cultured under hypoxic conditions showed greater therapeutic effects in mice with liver cirrhosis (114). Yu et al found that hypoxia preconditioning enhanced the expression of VEGF in BM-MSCs in vitro.…”

Molecular Pathways Modulated by Mesenchymal Stromal Cells and Their Extracellular Vesicles in Experimental Models of Liver Fibrosis

“…Anti-inflammatory effects of MSCs in liver tissue were evaluated by measuring the expression levels of pro-inflammatory cytokines in different animal models of CLD, such as HFD, MCDD, CCl 4 infusion, and TAA administration (Zhao et al, 2012;Nasir et al, 2013;Idriss et al, 2018;Bruno et al, 2019). These studies demonstrated that TNF-α, IL-6, and other pro-inflammatory cytokines [IL-1β, TGF-β1, INF-γ, and monocyte chemoattractant protein-1 (MCP-1)] were downregulated in the liver of treated mice (Zhao et al, 2012;Nasir et al, 2013;Idriss et al, 2018;Bruno et al, 2019;Choi et al, 2019;Kojima et al, 2019). In vitro: hepatocytes were seeded on a 6-well collagen-coated plate (1 × 104 cells/cm 2 ) and were subjected to injury with 3 mM and 5 mM CCl4.…”