Interleukin-3 induces hepatocyte-specific metabolic activity in bone marrow-derived liver stem cells

Progress in treatment of liver fibrosis by stem cells

Latest studies from home and abroad indicate that stem cells exist in different adult tissues and various stages of individual development. There are stem cells not only derived from liver, but also from other tissues, such as bone marrow and pancreas in liver, which can differentiate into mature hepatocyte-like cells finally. Therefore, stem cell replacement therapy offers a new way for the clinical treatment of hepatic fibrosis in patients with end-stage liver diseases. This paper summarizes the progress in treating liver fibrosis by stem cells in recent years.

Factors released from cholestatic rat livers possibly involved in inducing bone marrow hepatic stem cell priming

Previous studies have shown that bone marrow beta 2m(-)/Thy-1+ hepatic stem cells (BMHSCs) were able to engraft in vivo and differentiate into functioning hepatocytes in vitro. Our transcriptomic profiling on BMHSCs derived from rats subjected to common bile duct ligation (CBDL) demonstrated CBDL-derived beta 2m(-)/Thy-1+ BMHSCs expressed hepatocyte-like genes and shared more commonly expressed genes with hepatocytes, suggesting that an "on-site" priming of BMHSCs into hepatocyte lineage was initiated under the condition of CBDL. In this paper, transcriptomic profiling was carried out on livers from rats with CBDL to identify candidate factors released from cholestatic livers possibly involved in the priming of BMHSCs using Affymetrix Rat Genome U34A arrays. In CBDL rat livers, 1,091 probe sets were differentially expressed, of which 188 up-regulated probe sets were annotated as "extracellular" components. Gene ontology analysis showed many up-regulated genes belonged to cytokines, chemokines and growth factors, including Il1b, Il18, Ptn, Spp1, Grn, Ccl2, Cxcl1, Pf4, Tgfb, and Tgfb3. Cell differentiation and proliferation regulation factors such as Dmbt1, Efna1, Lgals1, Lep, Pmp2, and Gas6 were also induced in CBDL livers. Furthermore, many proteolysis and peptidolysis genes such as Mmp2, Mmp12, Mmp14, and Mmp23 were up-regulated in CBDL livers. Gene expression profiling showed that many cytokine-, chemokine-, growth factor- as well as certain extracellular protein-related genes were induced in CBDL livers, suggesting that these genes may be involved in hepatic BMHSCs priming.

Chemotaxis of stromal cell-dirived factor-1 on bone marrow mesenchymal stem cells

Bone marrow stem cells (BMC) mainly include hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC). MSC not only have the potential capability of self-renewal and multi-directional differentiation, but also have a higher plasticity to differentiate into a variety of cells under the specific conditions. In addition, MSC can be easily obtained, and have been extensively studied in recent years. Many studies in vivo and in vitro have confirmed that some cytokines can influence the microenvironment of transplanted cells, resulting in the mobilization, migration and differentiation of BMC. Stromal cell-derived factor-1 (SDF-1) is a CXC-type chemokine with a wide biological activity, and it also has chemotaxis effect on BMC, which is reviewed in this article.

Research progress in directional differentiation from bone marrow stem cells into hepatocyte-like cells

Recent researches indicate that bone marrow stem cells not only can differentiate into bone, cartilage, fat, muscle cells and various blood cells, but also can differentiate into cells of trans-germinal layer, such as ectoderm original neuronal cells, endoderm original hepatocytes, insular cells, under suitable microenvironment. It is called "plasticity" or "trans-differentiation". This paper reviews the research advances that bone marrow stem cell differentiation into hepatocyte-like cells and their clinical application in liver disease treatment.

Stem cells for liver tissue repair: Current knowledge and perspectives

Stem cells from extra- or intrahepatic sources have been recently characterized and their usefulness for the generation of hepatocyte-like lineages has been demonstrated. Therefore, they are being increasingly considered for future applications in liver cell therapy. In that field, liver cell transplantation is currently regarded as a possible alternative to whole organ transplantation, while stem cells possess theoretical advantages on hepatocytes as they display higher in vitro culture performances and could be used in autologous transplant procedures. However, the current research on the hepatic fate of stem cells is still facing difficulties to demonstrate the acquisition of a full mature hepatocyte phenotype, both in vitro and in vivo. Furthermore, the lack of obvious demonstration of in vivo hepatocyte-like cell functionality remains associated to low repopulation rates obtained after current transplantation procedures. The present review focuses on the current knowledge of the stem cell potential for liver therapy. We discuss the characteristics of the principal cell candidates and the methods to demonstrate their hepatic potential in vitro and in vivo. We finally address the question of the future clinical applications of stem cells for liver tissue repair and the technical aspects that remain to be investigated.

Granulocyte colony-stimulating factor supports liver regeneration in a small-for-size liver remnant mouse model

Experimental partial hepatectomy of more than 80% of the liver weight bears an increased mortality in rodents, due to impaired hepatic regeneration in small-for-size liver remnants. Granulocyte colony-stimulating factor (G-CSF) promotes progenitor cell expansion and mobilization and also has immunomodulatory properties. The aim of this study was to determine the effect of systemically administered G-CSF on liver regeneration and animal survival in a small-for-size liver remnant mouse model. Mice were preconditioned daily for 5 days with subcutaneous injections of 5 microg G-CSF or aqua ad injectabile. Subsequently, 83% partial hepatectomy was performed by resecting the median, the left, the caudate, and the right inferior hepatic lobes in all animals. Daily sham or G-CSF injection was continued. Survival was significantly better in G-CSF-treated animals (P < 0.0001). At 36 and 48 h after microsurgical hepatic resection, markers of hepatic proliferation (Ki67, BrdU) were elevated in G-CSF-treated mice compared to sham injected control animals (P < 0.0001) and dry liver weight was increased (P < 0.05). G-CSF conditioning might prove to be useful in patients with small-for-size liver remnants after extended hepatic resections due to primary or secondary liver tumors or in the setting of split liver transplantation.

Functional comparison of bone marrow-derived liver stem cells: selection strategy for cell-based therapy

Several distinct subpopulations of bone marrow-derived liver progenitor cells were recently described. However, there is inadequate information comparing these subpopulations from a liver-function point of view. This study was undertaken to compare two subpopulations of liver progenitors: beta(2)-microglobulin (beta(2)m)-negative/Thy-1-positive cells, and liver progenitors obtained from the non-adherent cell fraction after a panning procedure. The cells were cultured under several conditions including high- and low-dose hepatocyte growth factor, various cellular densities, and different media. Growth characteristics, liver-specific metabolic capacity, and liver regeneration-associated gene expression were studied. Both isolation procedures yielded cells that produced albumin and metabolized ammonia into urea. The study demonstrated that the beta(2)m-negative/Thy-1-positive cell fraction metabolized ammonia into urea more efficiently and produced a superior amount of albumin compared with the panned cell fraction. The beta(2)m-negative/Thy-1-positive cell fraction could be optimal for the development of novel cell-based treatment strategies for congenital or acquired liver diseases.