Objective Reports on the effects of bone marrow-derived cells on hepatic fibrosis are contradictory. Impaired fibrosis but increased inflammation has recently been demonstrated 10 weeks after bone marrow transplantation (BM-Tx) in Abcb4−/− mice. It is hypothesised that BM-Tx might have long-term therapeutic potential by altering the immunological and matrix remodelling processes leading to hepatic regeneration.
Methods After lethal irradiation of recipient mice, BM cells from GFP+ donor mice (allogeneic Tx) or Abcb4−/− mice (syngeneic Tx) were transplanted via tail vein injection. Readouts were performed 2, 10 and 20 weeks after Tx. Liver integrity was assessed serologically and histologically. Surrogate markers for fibrogenesis, T helper (Th) response, inflammation, graft-versus-host disease and fibrolysis were analysed by quantitative real-time PCR, zymography and immunohistology.
Results 20 weeks after syngeneic and allogeneic BM-Tx, hepatic grading and staging were significantly improved. In contrast, 2 weeks after BM-Tx inflammatory grading, expression of inflammatory cell markers and associated chemokines and their receptors were increased and subsequently declined. In parallel, CD8+/GFP+ donor-derived T cells infiltrated the liver 2 weeks after BM-Tx. The Th1 cyokine interferon γ was increased 2 and 10 weeks after BM-Tx whereas the Th2 associated interleukin 13 was not altered. The gene expression of matrix metalloproteinases MMP-2, MMP-7, MMP-9 and MMP-13 was transiently upregulated and MMP-9 protein remained elevated 20 weeks after BM-Tx with enhanced gelatinase activity located within the fibrotic areas. Neutrophils were identified as major sources of MMP-9.
Conclusion These results show that BM-Tx causes an antifibrotic Th1 response combined with transient inflammatory effects and subsequently upregulated MMP activity. Antifibrotic Th polarisation and prolonged proteolytic activity, especially of MMP-9, might be responsible for long-term amelioration of hepatic fibrosis.
- Liver fibrosis
- T-cell polarisation
- matrix metalloproteinase
- stem cells
- hepatic fibrosis
- inflammatory bowel disease
- liver cirrhosis
- matrix metalloproteinase
- IBD basic research
- acute hepatitis
- acute liver failure
- cell cycle control
- cell death
- helicobacter pylori
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MR and TR contributed equally to this paper.
Funding This work was supported by grants from the Deutsche Forschungsgemeinschaft (RO 957/8-1) and by a Research Grant from the University Medical Center Giessen and Marburg (UKGM 10/2010 GI). TR received starting grants from the Justus-Liebig-University Giessen.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.
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