Lesson from the GFP/CCl4 model--translational research project: the development of cell therapy using autologous bone marrow cells in patients with liver cirrhosis

Hepatic stellate cell-specific knockout of transcriptional intermediary factor 1γ aggravates liver fibrosis

Transforming growth factor β (TGFβ) is a crucial factor in fibrosis, and transcriptional intermediary factor 1γ (TIF1γ) is a negative regulator of the TGFβ pathway; however, its role in liver fibrosis is unknown. In this study, mesenchymal stem cells derived from human embryonic stem cells (hE-MSCs) that secrete hepatocyte growth factor (HGF) were used to observe the repair of thioacetamide (TAA)-induced liver fibrosis. Our results showed that TIF1γ was significantly decreased in LX2 cells when exposed to TGFβ1. Such decrease of TIF1γ was significantly prevented by co-culture with hE-MSCs. Interaction of TIF1γ with SMAD2/3 and binding to the promoter of the α-smooth muscle gene (αSMA) suppressed αSMA expression. Phosphorylation of cAMP response element-binding protein (CREB) and binding on the TIF1γ promoter region induced TIF1γ expression. Furthermore, hepatic stellate cell-specific TIF1γ-knockout mice showed aggravation of liver fibrosis. In conclusion, loss of TIF1γ aggravates fibrosis, suggesting that a strategy to maintain TIF1γ during liver injury would be a promising therapeutic approach to prevent or reverse liver fibrosis.

Recent updates on phthalate exposure and human health: a special focus on liver toxicity and stem cell regeneration

Phthalates have been blended in various compositions as plasticizers worldwide for a variety of purposes. Consequently, humans are exposed to a wide spectrum of phthalates that needs to be researched and understood correctly. The goal of this review is to focus on phthalate's internal exposure pathways and possible role of human digestion on liver toxicity. In addition, special focus was made on stem cell therapy in reverting liver toxicity. The known entry of higher molecular weight phthalates is through ingestion while inhalation and dermal pathways are for lower molecular weight phthalates. In human body, certain phthalates are digested through phase 1 (hydrolysis, oxidation) and phase 2 (conjugation) metabolic processes. The phthalates that are made bioavailable through digestion enter the blood stream and reach the liver for further detoxification, and these are excreted via urine and/or feces. Bis(2-ethylhexyl) phthalate (DEHP) is a compound well studied involving human metabolism. Liver plays a pivotal role in humans for detoxification of pollutants. Thus, continuous exposure to phthalates in humans may lead to inhibition of liver detoxifying enzymes and may result in liver dysfunction. The potential of stem cell therapy addressed herewith will revert liver dysfunction and lead to restoration of liver function properly.

A canine liver fibrosis model to develop a therapy for liver cirrhosis using cultured bone marrow-derived cells

We have been developing a therapy for liver cirrhosis using cultured autologous bone marrow-derived mesenchymal stem cells (BMSCs). Before human clinical trials can be considered, the safety and efficacy of BMSC infusion in medium to large animals must be confirmed; thus, we developed a canine liver fibrosis model. A small amount of bone marrow fluid was aspirated from the canine humerus to assess the characteristics of BMSCs. We implanted a venous catheter in the stomach and a subcutaneous infusion port in the back of the neck of each canine. Repeated injection of CCl₄ through the catheter was performed to induce liver cirrhosis. After 10 weeks of CCl₄ injection, eight canines were equally divided into two groups: no cell infusion (control group) and autologous BMSC infusion through the peripheral vein (BMSC group). A variety of assays were carried out before and 4 weeks after the infusion. The area of liver fibrosis stained with sirius red was significantly reduced in the BMSC group 4 weeks after BMSC infusion, consistent with a significantly shortened half-life of indocyanine green and improved liver function. Conclusion: We established a useful canine liver fibrosis model and confirmed that cultured autologous BMSC infusion improved liver fibrosis without adverse effects. (Hepatology Communications 2017;1:691-703).

Paracrine Effects of Bone Marrow Mononuclear Cells in Survival and Cytokine Expression after 90% Partial Hepatectomy

Acute liver failure is a complex and fatal disease. Cell-based therapies are a promising alternative therapeutic approach for liver failure due to relatively simple technique and lower cost. The use of semipermeable microcapsules has become an interesting tool for evaluating paracrine effects in vivo. In this study, we aimed to assess the paracrine effects of bone marrow mononuclear cells (BMMC) encapsulated in sodium alginate to treat acute liver failure in an animal model of 90% partial hepatectomy (90% PH). Encapsulated BMMC were able to increase 10-day survival without enhancing liver regeneration markers. Gene expression of Il-6 and Il-10 in the remnant liver was markedly reduced at 6 h after 90% PH in animals receiving encapsulated BMMC compared to controls. This difference, however, was neither reflected by changes in the number of CD68+ cells nor by serum levels of IL6. On the other hand, treated animals presented increased caspase activity and gene expression in the liver. Taken together, these results suggest that BMMC regulate immune response and promote apoptosis in the liver after 90% PH by paracrine factors. These changes ultimately may be related to the higher survival observed in treated animals, suggesting that BMMC may be a promising alternative to treat acute liver failure.

Autologous Peripheral Blood Stem Cell Transplantation Improves Portal Hemodynamics in Patients with Hepatitis B Virus-related Decompensated Cirrhosis

BACKGROUND

Chronic hepatitis B virus (HBV) infection may eventually lead to decompensated liver cirrhosis, which is a terminal illness.

OBJECTIVES

The aim of this study was to investigate the therapeutic efficacy of autologous peripheral blood stem cell (APBSC) transplantation to improve portal vein hemodynamics in patients with HBV-related decompensated cirrhosis.

PATIENTS AND METHODS

This prospective study included 68 hospitalized patients who were diagnosed with HBV-related decompensated cirrhosis. These patients were divided into two groups: the transplantation group included 33 patients, while the control group included 35. Both groups received conventional medical treatment simultaneously, and APBSC transplantation was performed on the patients in the transplantation group. We evaluated the effects of APBSC transplantation on postoperative liver function using the following indices: total bilirubin, serum prothrombin and albumin, spleen size, and portal vein hemodynamics. Postoperatively, all of the patients were followed up at 24, 36, and 48 weeks.

RESULTS

The transplantation group had no serious reactions. Compared with the control group, albumin and prothrombin activity in the transplantation group was significantly improved at 24, 36, and 48 weeks after the procedure, and spleen length and portal vein diameter were substantially reduced at 48 weeks. The velocity of peak portal vein blood flow and mean maximum portal vein blood flow were greatly increased in the APBSC transplantation group at 36 and 48 weeks, respectively; however, there was also decreased portal vein diameter, which reduced portal vein pressure in patients with HBV-related decompensated cirrhosis.

CONCLUSIONS

APBSC transplantation greatly benefits HBV-linked decompensated cirrhosis patients and should be recommended in clinical practice.

Mesenchymal stem cell therapy for cirrhosis: Present and future perspectives

Cirrhosis occurs as a result of various chronic liver injuries, which may be caused by viral infections, alcohol abuse and the administration of drugs and chemicals. Recently, bone marrow cells (BMCs), hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) have been used for developing treatments for cirrhosis. Clinical trials have investigated the therapeutic potential of BMCs, HSCs and MSCs for the treatment of cirrhosis based on their potential to differentiate into hepatocytes. Although the therapeutic mechanisms of BMC, HSC and MSC treatments are still not fully characterized, the evidence thus far has indicated that the potential therapeutic mechanisms of MSCs are clearer than those of BMCs or HSCs with respect to liver regenerative medicine. MSCs suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, reverse liver fibrosis and enhance liver functionality. This paper summarizes the clinical studies that have used BMCs, HSCs and MSCs in patients with liver failure or cirrhosis. We also present the potential therapeutic mechanisms of BMCs, HSCs and MSCs for the improvement of liver function.

Status and prospects of liver cirrhosis treatment by using bone marrow-derived cells and mesenchymal cells

In 2003, we started autologous bone marrow cell infusion (ABMi) therapy for treating liver cirrhosis. ABMi therapy uses 400 mL of autologous bone marrow obtained under general anesthesia and infused mononuclear cells from the peripheral vein. The clinical study expanded and we treated liver cirrhosis induced by HCV and HBV infection and alcohol consumption. We found that the ABMi therapy was effective for cirrhosis patients and now we are treating patients with combined HIV and HCV infection and with metabolic syndrome-induced liver cirrhosis. Currently, to substantiate our findings that liver cirrhosis can be successfully treated by the ABMi therapy, we are conducting randomized multicenter clinical studies designated "Advanced medical technology B" for HCV-related liver cirrhosis in Japan. On the basis of our clinical study, we developed a proof-of-concept showing that infusion of bone marrow cells (BMCs) improved liver fibrosis and sequentially activated proliferation of hepatic progenitor cells and hepatocytes, further promoting restoration of liver functions. To treat patients with severe forms of liver cirrhosis, we continued translational research to develop less invasive therapies by using mesenchymal stem cells derived from bone marrow. We obtained a small quantity of BMCs under local anesthesia and expanded them into mesenchymal stem cells that will then be used for treating cirrhosis. In this review, we present our strategy to apply the results of our laboratory research to clinical studies.

Bone marrow injection stimulates hepatic ductular reactions in the absence of injury via macrophage-mediated TWEAK signaling

Tissue progenitor cells are an attractive target for regenerative therapy. In various organs, bone marrow cell (BMC) therapy has shown promising preliminary results, but to date no definite mechanism has been demonstrated to account for the observed benefit in organ regeneration. Tissue injury and regeneration is invariably accompanied by macrophage infiltration, but their influence upon the progenitor cells is incompletely understood, and direct signaling pathways may be obscured by the multiple roles of macrophages during organ injury. We therefore examined a model without injury; a single i.v. injection of unfractionated BMCs in healthy mice. This induced ductular reactions (DRs) in healthy mice. We demonstrate that macrophages within the unfractionated BMCs are responsible for the production of DRs, engrafting in the recipient liver and localizing to the DRs. Engrafted macrophages produce the cytokine TWEAK (TNF-like weak inducer of apoptosis) in situ. We go on to show that recombinant TWEAK activates DRs and that BMC mediated DRs are TWEAK dependent. DRs are accompanied by liver growth, occur in the absence of liver tissue injury and hepatic progenitor cells can be isolated from the livers of mice with DRs. Overall these results reveal a hitherto undescribed mechanism linking macrophage infiltration to DRs in the liver and highlight a rationale for macrophage derived cell therapy in regenerative medicine.

Bone-marrow-derived cells cultured in serum-free medium reduce liver fibrosis and improve liver function in carbon-tetrachloride-treated cirrhotic mice

We have previously developed autologous bone marrow cell infusion (ABMi) therapy for liver cirrhosis patients. One problem associated with ABMi therapy is that general anesthesia is required to obtain 400 ml bone marrow fluid from liver cirrhosis patients. However, many patients with decompensated cirrhosis do not meet the criteria, because of decreased liver function or an increased bleeding tendency. To overcome these issues, our aim is to derive liver repair cells from small amounts of autologous bone marrow aspirates obtained under local anesthesia and to use these cells in liver cirrhosis patients. Here, we conducted, by using a mouse model, basic research aimed at achieving novel liver regeneration therapy. We cultured bone marrow cells aspirated from the femurs of C57 BL/6 Tg14 (act-EGFP) OsbY01 mice (green fluoresent protein [GFP]-transgenic mice). After 14 days of culture with serum-free medium (good manufacturing practice grade), the obtained spindle-shaped GFP-positive cells were injected (1×10(4) cells) via the caudal vein into mice with carbon tetrachloride (CCl4)-induced cirrhosis. Numerous cultured macrophages and some mesenchymal stem cells repopulated the cirrhotic liver. The results showed that serum albumin, liver fibrosis and liver function were significantly improved in the group treated with cultured bone marrow cells (P<0.01). Moreover, matrix metalloproteinase-9 expression was increased in the liver (P<0.01). Thus, infusion of bone-marrow-derived cultured cells improved liver function and liver fibrosis in mice with CCl4-induced cirrhosis.

Timeline for development of autologous bone marrow infusion (ABMi) therapy and perspective for future stem cell therapy

Liver cirrhosis patients generally progress to liver failure. To cure this progressive disease, we developed a novel cell therapy using bone marrow cells; autologous bone marrow cell infusion (ABMi) therapy. We previously described the possible action mechanism of ABMi therapy in the cirrhotic liver, and showed the timeline and results of clinical studies of ABMi therapy. We have also carried out other clinical studies using bone marrow cells and granulocyte colony-stimulating factor. Here, we report a new randomized clinical trial to evaluate the effects of ABMi therapy. However, ABMi therapy may not be possible in patients who are unable to undergo general anesthesia; therefore, we have started to develop a next-generation stem cell therapy using cultured mesenchymal stem cells.

Granulocyte colony-stimulating factor and interleukin-1β are important cytokines in repair of the cirrhotic liver after bone marrow cell infusion: comparison of humans and model mice

We previously described the effectiveness of autologous bone marrow cell infusion (ABMi) therapy for patients with liver cirrhosis (LC). We analyzed chronological changes in 19 serum cytokines as well as levels of specific cytokines in patients after ABMi therapy and in a mouse model of cirrhosis generated using green fluorescent protein (GFP)/carbon tetrachloride (CCl4). We measured expression profiles of cytokines in serum samples collected from 13 patients before and at 1 day and 1 week after ABMi. Child-Pugh scores significantly improved in all of these patients. To analyze the meaning of early cytokine change, we infused GFP-positive bone marrow cells (BMCs) into mice with CCl4-induced LC and obtained serum and tissue samples at 1 day and as well as at 1, 2, 3, and 4 weeks later. We compared chronological changes in serum cytokine expression in humans and in the model mice at 1 day and 1 week after BMC infusion. Among 19 cytokine, both granulocyte colony-stimulating factor (G-CSF) and interleukin-1β(IL-1β) in serum was found to show the same chronological change pattern between human and mice model. Next, we examined changes in cytokine expression in cirrhosis liver before and at 1, 2, 3, and 4 weeks after BMC infusion. Both G-CSF and IL-1β were undetectable in the liver tissues before and at 1 week after BMC infusion but increased at 2 weeks and continued until 4 weeks after infusion. The infused BMCs induced an early decrease of both G-CSF and IL-1β in serum and an increase in the model mice with LC. These dynamic cytokine changes might be important to repair liver cirrhosis after BMC infusion.

Autologous bone marrow cell infusions suppress tumor initiation in hepatocarcinogenic mice with liver cirrhosis

We have previously reported the efficacy and safety of autologous bone marrow cell infusion (ABMi) therapy for liver cirrhosis patients without hepatocellular carcinoma in a multicenter clinical trial. However, since liver cirrhosis is highly oncogenic, evaluation of the effects of ABMi on the mechanisms of hepatocarcinogenesis is of great importance. Therefore, frequent ABMi was performed in hepatocarcinogenic mice, and its effects on hepatocarcinogenesis were analyzed. The N-nitrosodiethylamine (DEN)/green fluorescent protein (GFP)-carbon tetrachloride (CCl(4) ) model was developed by administering DEN once, followed by repeated administration of CCl(4) intraperitoneally as for the control group. In the administration (ABMi) group, GFP-positive bone marrow cells were infused through a tail vein. The kinetics of hepatocarcinogenesis were evaluated histologically 4.5 months after DEN treatment. At 4.5 months, there was significantly lower incidence of foci and tumors in the ABMi group, and they were smaller in number, while their size was almost equal. No GFP-positive tumors were found in ABMi livers. Moreover, ABMi livers showed significantly reduced liver fibrosis, consistent with significantly lower 8-hydroxy-2'-deoxyguanosine levels, higher superoxide dismutase activity, and increased nuclear translocation of nuclear factor-erythroid 2 p45-related factor 2. These results demonstrate that frequent ABMi might contribute to suppressed tumor initiation during stages of hepatocarcinogenesis, consistent with improvements in liver fibrosis and stabilization of redox homeostasis.

Splenectomy enhances the anti-fibrotic effect of bone marrow cell infusion and improves liver function in cirrhotic mice and patients

BACKGROUND

In 2003, we initiated a clinical trial to examine autologous bone marrow cell infusion (ABMi) therapy for cirrhotic patients and reported the clinical effect of the therapy. To analyze how splenectomy may potentiate the effects of bone marrow cell infusion on cirrhosis, we performed a mouse study and a clinical trial on patients with cirrhosis.

METHODS

In mice, we analyzed the effect of splenectomy on bone marrow cell infusion in four experimental groups (group A, splenectomy + bone marrow cell infusion + CCl(4); group B, sham operation + bone marrow cell infusion + CCl(4); group C, splenectomy + CCl(4); group D, sham operation + CCl(4)). In clinical, we compared the effect of splenectomy on ABMi therapy.

RESULTS

We observed significantly increased average serum albumin levels and higher expression of green fluorescent protein (GFP), matrix metalloproteinase 9 (MMP9), and proliferating cell nuclear antigen in the livers of group A. We observed MMP9/GFP double-positive cells in the cirrhotic livers. A significant decrease in the liver fibrosis areas was observed in group A. Splenectomy enhanced the repopulation of bone marrow cells into the cirrhotic liver and improved the liver microenvironment via expression of MMP9 secreted from repopulating GFP-positive cells. Next, we performed a clinical trial to compare the effect of splenectomy on the efficacy of ABMi therapy. Cirrhotic patients who underwent splenectomy before ABMi therapy tended to have a greater improvement in liver function.

CONCLUSION

ABMi therapy with splenectomy may be an effective therapeutic modality for cirrhosis.

Therapeutic potential of canine bone marrow stromal cells (BMSCs) in the carbon tetrachloride (CCl4) induced chronic liver dysfunction mouse model

Regenerative medicine using bone marrow cells is an attractive therapy for the cure of patients with severe liver disease. Here, we show the therapeutic potential of canine bone marrow stromal cells (BMSCs) in mouse models of CCl(4)-induced chronic liver dysfunction. We used two different models for xenotransplantation, nude mice and cyclosporine A (CSA) immunosuppressed mice. Serum parameters from a standard liver panel were not improved following transplantation. However, fibrotic liver lesions with severe inflammation were decreased in CCl(4)-treated CSA mice following BMSC transplantation. Effective migration of transplanted canine BMSCs was limited to persistently injured liver in CCl(4)-treated CSA mice, where they may be effective in resolving inflammatory fibrotic lesions. These results suggest that canine BMSCs are an effective cell source for liver regeneration.

Matrix metalloproteinases (MMPs) activity in cultured canine bone marrow stromal cells (BMSCs)

Autologous bone marrow stromal cells (BMSCs) infusion therapy improves the hepatic fibrosis. To investigate the mechanism of remission, we evaluated the matrix metalloproteinase (MMP)-2 and -9 activity in canine BMSCs and the effect of pro-inflammatory cytokines on their expression. The activity and the gene expression of MMPs were analyzed by gelatin zymography and quantitative RT-PCR, respectively. The specific gelatinase bands were indicative effect of MMP-2 and -9 in canine BMSCs. MMP-2 expression seemed to be increased by TNF-α and IL-1β while MMP-9 was enhanced by TNF-α and IL-6. These results suggested that remissive effect on liver fibrosis might be partly attributable to the MMP-2 and -9 activity in BMSCs under the inflammatory condition.

TNFR1-mediated signaling is important to induce the improvement of liver fibrosis by bone marrow cell infusion

The importance of TNF-α signals mediated by tumor necrosis factor receptor type 1 (TNFR1) in inflammation and fibrosis induced by carbon tetrachloride (CCl₄), and in post-injury liver regeneration including a GFP/CCl₄ model developed as a liver repair model by bone marrow cell (BMC) infusion, was investigated. In mice in which TNFR1 was suppressed by antagonist administration or by knockout, liver fibrosis induced by CCl₄ was significantly decreased. In these mice, intrahepatic macrophage infiltration and TGF-β1 expression were reduced and stellate cell activity was decreased; however, expression of MMP-9 was also decreased. With GFP-positive BMC (TNFR1 wild-type, WT) infusion in these mice, fibrosis proliferation, including host endogenous intrahepatic macrophage infiltration, TGF-β1 expression and stellate cell activity, increased significantly. There was no significant increase of MMP-9 expression. In this study, TNFR1 in hosts had a promoting effect on CCl₄-induced hepatotoxicity and fibrosis, whereas BMC infusion in TNFR1 knockout mice enhanced host-derived intrahepatic inflammation and fibrosis proliferation. These findings differed from those in WT recipient mice, in which improvement in inflammation and fibrosis with BMC infusion had previously been reported. TNFR1-mediated signaling might be important to induce the improvement of liver fibrosis by bone marrow cell infusion.

Autologous bone marrow cell infusion therapy for liver cirrhosis patients

We developed a novel cell therapy, autologous bone marrow cell infusion (ABMi) therapy, using autologous bone marrow, for liver cirrhosis patients. Our study depends on the findings from basic studies that bone marrow cell infusion repairs liver fibrosis in the cirrhotic liver, and improves liver function and the survival rate. Beginning in November 2003, we started a clinical study and found that ABMi therapy was safe and effective for liver cirrhosis patients. Multicenter trials in Japan and Korea have also shown the effectiveness of ABMi therapy. In this review, we report the current status of ABMi therapy for liver cirrhosis patients.

Efficacy of mesenchymal stem cells in suppression of hepatocarcinorigenesis in rats: possible role of Wnt signaling

Background

The present study was conducted to evaluate the tumor suppressive effects of bone marrow derived mesenchymal stem cells (MSCs) in an experimental hepatocellular carcinoma (HCC) model in rats and to investigate the possible role of Wnt signaling in hepato-carcinogenesis.

Methods

Ninety rats were included in the study and were divided equally into: Control group, rats which received MSCs only, rats which received MSCs vehicle only, HCC group induced by diethylnitroseamine (DENA) and CCl₄, rats which received MSCs after HCC induction, rats which received MSCs before HCC induction. Histopathological examination and gene expression of Wnt signaling target genes by real time, reverse transcription-polymerase chain reaction (RT-PCR) in rat liver tissue, in addition to serum levels of ALT, AST and alpha fetoprotein were performed in all groups.

Results

Histopathological examination of liver tissue from animals which received DENA-CCl₄ only, revealed the presence of anaplastic carcinoma cells and macro-regenerative nodules type II with foci of large and small cell dysplasia. Administration of MSCs into rats after induction of experimental HCC improved the histopathological picture which showed minimal liver cell damage, reversible changes, areas of cell drop out filled with stem cells. Gene expression in rat liver tissue demonstrated that MSCs downregulated β-catenin, proliferating cell nuclear antigen (PCNA), cyclin D and survivin genes expression in liver tissues after HCC induction. Amelioration of the liver status after administration of MSCs has been inferred by the significant decrease of ALT, AST and Alpha fetoprotein serum levels. Administration of MSCs before HCC induction did not show any tumor suppressive or protective effect.

Conclusions

Administration of MSCs in chemically induced HCC has tumor suppressive effects as evidenced by down regulation of Wnt signaling target genes concerned with antiapoptosis, mitogenesis, cell proliferation and cell cycle regulation, with subsequent amelioration of liver histopathological picture and liver function.

Novel findings for the development of drug therapy for various liver diseases: Current state and future prospects for our liver regeneration therapy using autologous bone marrow cells for decompensated liver cirrhosis patients

We have developed an in vivo mouse model [the green fluorescent protein (GFP) / carbon tetrachloride (CCl(4)) model] and reported that infused GFP-positive bone marrow cells administered via a tail vein efficiently repopulated cirrhotic liver tissue under conditions of persistent liver damage induced by CCl(4). Moreover, bone marrow cells infused into the liver improved liver function and ameliorated liver fibrosis with higher expression of matrix metalloproteinase 9 (MMP-9), consistent with improved survival rate. Based on these findings, we started a multicenter clinical trial of autologous bone marrow cell infusion (ABMi) therapy for decompensated liver cirrhosis patients and demonstrated the efficacy of this approach without unexpected complications. However, this therapy involves bone marrow aspiration under general anesthesia and is not indicated for patients for whom general anesthesia is difficult. We therefore aimed to develop a new liver regeneration therapy in which cells having a curative effect on liver cirrhosis are isolated and cultured from a small amount of autologous bone marrow aspirated under local anesthesia and infused back into the same subject. Herein, we present results for the GFP/CCl(4) model and ABMi therapy and future prospects for a new liver regeneration therapy.

Advances in research of the reversal of liver fibrosis by transplantation of bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs) are a group of stem cells capable of multilineage differentiation. Under given conditions, BMSCs can differentiate into a variety of cells, such as osteoblasts, chondrocytes, adipocytes, neuron-like cells and hepatocytes. In recent years, numerous studies have shown that BMSCs can not only inhibit and reduce liver fibrosis but also induce immunosuppression and immune tolerance. Therefore, transplantation of BMSCs can be used to treat end-stage liver disease.

Mesenchymal stem cells showed the highest potential for the regeneration of injured liver tissue compared with other subpopulations of the bone marrow

We have previously reported that bone marrow cells (BMCs) participate in the regeneration after liver injury. However, it is not established that this is the result of differentiation of hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs) or the combination of both. We investigated the contribution of each cell fraction to the regenerative process. First, we confirmed that transplanted stem cells migrate directly to injured liver tissue without dispersing to other organs. Next, we divided green fluorescent protein (GFP)-expressing BMCs into three populations as mononuclear cells, MSCs and HSCs. We then compared the engraftment capacity after transplantation of each fraction of cells into liver-injured mice. Of these, the MSCs transplanted group showed the highest GFP fluorescence intensities in liver tissue by flow cytometry analysis and confocal microscopic observation. Furthermore, MSCs showed differentiation potential into hepatocytes when co-cultured with injured liver cells, which suggests that MSCs showed highest potential for the regeneration of injured liver tissue compared with those of the other two cell refractions.

Cell Transplantation of Adipose Tissue-Derived Stem Cells in Combination with Heparin Attenuated Acute Liver Failure in Mice

The effect of adipose tissue-derived stem cells (ASCs) in combination with heparin transplantation on acute liver failure mice with carbon tetrachloride (CCl4) injection was investigated. CCl4 is a well-known hepatotoxin and induces hepatic necrosis. Heparin did not affect the viability of ASCs for at least 24 h. The injection of heparin into the caudal tail vein decreased slightly the activities of the alanine aminotransferase (ALT), asparate aminotransferase (AST), and lactate dehydrogenase (LDH) in plasma. In the transplantation of ASCs (1 × 106 cells) group, there was a trend toward decreased activities of all markers. However, four out of six mice died of the lung infarction. In the transplantation of ASCs in combination with heparin group, there was also a trend toward decreased activities of all markers. In addition, all mice survived for at least the duration of the study period. In conclusion, the transplantation of ASCs in combination with heparin was thus found to effectively treat acute liver failure.

Stem cells in liver regeneration, fibrosis and cancer: the good, the bad and the ugly

The worldwide shortage of donor livers to transplant end stage liver disease patients has prompted the search for alternative cell therapies for intractable liver diseases, such as acute liver failure, cirrhosis and hepatocellular carcinoma (HCC). Under normal circumstances the liver undergoes a low rate of hepatocyte 'wear and tear' renewal, but can mount a brisk regenerative response to the acute loss of two-thirds or more of the parenchymal mass. A body of evidence favours placement of a stem cell niche in the periportal regions, although the identity of such stem cells in rodents and man is far from clear. In animal models of liver disease, adopting strategies to provide a selective advantage for transplanted hepatocytes has proved highly effective in repopulating recipient livers, but the poor success of today's hepatocyte transplants can be attributed to the lack of a clinically applicable procedure to force a similar repopulation of the human liver. The activation of bipotential hepatic progenitor cells (HPCs) is clearly vital for survival in many cases of acute liver failure, and the signals that promote such reactions are being elucidated. Bone marrow cells (BMCs) make, at best, a trivial contribution to hepatocyte replacement after damage, but other BMCs contribute to the hepatic collagen-producing cell population, resulting in fibrotic disease; paradoxically, BMC transplantation may help alleviate established fibrotic disease. HCC may have its origins in either hepatocytes or HPCs, and HCCs, like other solid tumours appear to be sustained by a minority population of cancer stem cells.

Current status of autologous bone marrow cell infusion therapy for liver cirrhosis patients

This article reviews recent translational research on the development of cell therapy using autologous bone marrow cell for liver cirrhosis patients. A clinical study of autologous bone marrow cell infusion (ABMI) therapy for liver cirrhosis patient was begun on Nov. 14, 2003. We previously reported nine liver cirrhosis (LC) cases that underwent ABMI from the peripheral vein and followed their progress up to 24 weeks. Subjects were LC patients with total bilirubin TB of < 3.0 mg/dL, platelets > 5 (10(10)/L) and no viable hepatocellular carcinoma on diagnostic imaging. Mononuclear cells (MNCs) were separated by cell washing and were infused via the peripheral vein. After ABMI therapy liver function and Child-Pugh Score were significantly improved at 4 weeks and 24 weeks (P < 0.05). A total of 23 cases of ABMI therapy have been performed for LC patients to date. No major adverse effects were noted due to ABMI therapy. In conclusion, ABMI therapy should be considered as a novel treatment for LC patients.

Stem cell therapy for inherited metabolic disorders of the liver

Modern medicine has conquered an enormous spectrum of health concerns, from the neonatal to the geriatric, the chronically ill to the acutely injured. Among the unmet challenges remaining in modern medicine are inborn disorders of metabolism within the liver. Such inherited metabolic disorders (IMDs) often leave an otherwise healthy individual with a crippling imbalance. As the principal regulator of the body's many metabolic pathways, malencoded hepatic enzymes can drastically disrupt homeostasis throughout the entire body. Severe phenotypes are usually detected within the first few days of life, and treatments range from palliative lifestyle modifications to aggressive surgical procedures. While orthotopic liver transplantation is the single last resort "cure" for these conditions, research during the past few years has brought new therapeutic technologies ever closer to the clinic. Stem cells, therapeutic viral vectors, or a combination thereof, are projected to be the next, best, and final cure for IMDs, which is well-reflected by this generation's research initiatives.

The role of bone marrow-derived cells in fibrosis

There is a growing realization that bone marrow-derived cells (BMDCs) are a potential therapy for many diseases including ischemic heart disease, arterial stenosis and osteogenesis imperfecta. On the other hand, the fact that BMDCs may also contribute to fibrosis in many solid organs as well as to fibrosis surrounding tumours suggests that BMDCs are also involved in disease progression. This review focuses on the contribution of bone marrow cells to organ and tumour fibrosis, noting the utility of BMDCs as a potential new portal through which to direct anti-tumour therapies. Conversely, bone marrow cell therapy has been claimed to reduce fibrosis in some organs, highlighting a seemingly beneficial as opposed to a detrimental effect of BMDCs on organ fibrosis.

Continuous high expression of XBP1 and GRP78 is important for the survival of bone marrow cells in CCl4-treated cirrhotic liver

We have previously shown that infusion of bone marrow cells (BMC) improves CCl(4)-induced cirrhosis. However, it is unclear why the injected BMC are resistant to CCl(4) damage and subsequently improve the local microenvironment in damaged liver. To analyze the cellular phenomena involved in this process, we studied the damaged liver using electron microscopy. We found that CCl(4) caused rough endoplasmic reticula to swell in hepatocytes. To analyze the gene expression patterns associated with this process, we conducted PCR-selected suppressive subtractive hybridization. We found that expression levels of HSP84, HSP40, and XBP1 differed markedly between control liver and liver infused with BMC. Immunohistochemical staining revealed that expression levels of HSP84 and HSP40 were markedly higher in the early phase of differentiation immediately after BMC infusion, but decreased over time. XBP1 expression remained high during the late phase, and GRP78 expression increased with XBP1 activation. We also found that GFP-positive BMC expressed XBP1 and GRP78. XBP1 and GRP78 are associated with ER stress. Thus, continuous high XBP1 and GRP78 expression might be essential for the survival and proliferation of BMC in a CCl(4)-induced persistent liver damage environment.

Bone marrow cell transplant does not prevent or reverse murine liver cirrhosis

We tested the effect of bone marrow cell (BMC) transplantation in either preventing or reversing cirrhosis on an experimental model of chronic liver disease. Female Wistar rats were fed a liquid alcohol diet and received intraperitoneal injections of carbon tetrachloride (CCl4) over 15 weeks. Ten animals (cell-treated group) received five injections of BMCs during the cirrhosis induction protocol (on the 4th, 6th, 8th, 10th, and 12th weeks) and four animals received the cells after liver injury was established through tail vein. Nine animals (nontreated group) were submitted to the previously described protocols; however, they received vehicle injections. Analyses were performed to verify whether the infusion of cells was effective in preventing the development of cirrhosis in our model of induction, and if the cells could reverse cirrhosis once it was established. Hepatic architecture and fibrotic septa were analyzed in liver slices stained with hematoxilin & eosin and Sirius red, respectively. Fibrosis quantification was measured by Sirius red histomorphometry. Indirect immunofluorescence was performed to detect the amount of tissue transglutaminase 2. Blood analyses were performed to assess liver injury and function by the assessment of alanine aminotransferase and albumin. Ultrasound was performed to analyze the portal vein caliber and presence of ascitis. Cirrhosis features (regenerative nodules and fibrous septa) were observed in histopathology after 15 weeks of continuous hepatic injury in nontreated and cell-treated groups. Collagen content, immunofluorescence analysis, and biochemical and ultrasound parameters were similar in nontreated and cell-treated groups; however, both groups showed significant differences compared to a normal control group. Cell infusions with bone marrow-derived cells seem to be ineffective in improving morphofunctional parameters of the liver when applied to chronic cases either during or after establishment of the hepatic lesion.

Application of liver stem cells for cell therapy

The worldwide shortage of donor livers to transplant end stage liver disease patients has prompted the search for alternative cell therapies for intractable liver disease. Embryonic stem cells can be readily differentiated into hepatocytes, and their transplantation into animals has improved liver function in the absence of teratoma formation: their use in bioartificial liver support is an obvious application. In animal models of liver disease, adopting strategies to provide a selective advantage for transplanted foetal or adult hepatocytes have proved highly effective in repopulating recipient livers, but the poor success of today's hepatocyte transplants can be attributed to the lack of a clinically applicable procedure to force a similar repopulation of the human liver. The activation of bipotential hepatic progenitor cells is clearly vital for survival in many cases of acute liver failure, but surprisingly little progress has been made with these cells in terms of transplantation. Finally there is the controversial subject of autologous bone marrow, and while the contribution of these indigenous cells to liver turnover seems at best, trivial, results from a small number of phase 1 studies of transplantation of bone marrow to cirrhotic patients have been moderately encouraging.

Syngenic bone marrow cells restore hepatic function in carbon tetrachloride-induced mouse liver injury

Progenitor cells in bone marrow have been explored for the treatment of liver injury. Stem cell homing to the injured tissue is regulated through stromal cell derived factor-1 (SDF-1) and its receptor CXCR4. We hypothesized that syngenic bone marrow cells (BMCs) would restore hepatic function in the injured liver through the regulation by SDF-1/CXCR4 system. After injecting carbon tetrachloride (CCl(4)), the mice were injected with syngenic BMCs or normal saline. Morphological and functional analysis of the liver was performed. Flow cytometry for the stem cell markers and CXCR4 was done with the liver, BM, and spleen cells from each group. Carboxyfluorescein diacetate succinimidyl ester was used to trace the homing of transplanted BMCs. The SDF-1 expression of the liver was assessed by immunohistochemistry. Hepatosplenomegaly and necrosis of the CCl(4)-injected mouse liver were improved after BMCs transplantation The hepatic enzymes were increased after injury and then decreased after BMCs transplantation. The expression of stem cell markers and CXCR4 was exclusively increased in the damaged liver compared to the BM and spleen, and even more elevated after BMCs transplantation. SDF-1 expression in the liver was observed after CCl(4) injection and it was elevated after BMCs transplantation. The intrinsic and extrinsic BMCs migrate specifically to the injured liver rather than BM or spleen, and the transplanted BMCs contribute to the repair of the damaged liver. SDF-1/CXCR-4 interaction plays a role in stem cell homing toward the damaged organ, and transplanted BMCs are involved in the up-regulated SDF-1 expression seen in the injured liver.

Improved Liver Function in Patients with Liver Cirrhosis After Autologous Bone Marrow Cell Infusion Therapy

We here report nine liver cirrhosis (LC) patients that underwent autologous bone marrow cell infusion (ABMI) from the peripheral vein. Subjects were patients with LC with total bilirubin of less than 3.0 mg/dl, platelet count of more than 5 (10(10)/l), and no viable hepatocellular carcinoma on diagnostic imaging. Autologous bone marrow (BM; 400 ml) was isolated from the ilium under general anesthesia. Mononuclear cells (MNCs) were separated by cell washing and were infused via the peripheral vein. MNC characteristics were confirmed by fluorescence-activated cell sorting analysis (CD34, CD45, and c-kit). After ABMI therapy, liver function was monitored by blood examination for 24 weeks. From 400 ml of BM, we obtained 7.81 +/- 0.98 x 10(9) MNCs. After washing, 5.20 +/- 0.63 x 10(9) MNCs were infused into patients with LC. Significant improvements in serum albumin levels and total protein were observed at 24 weeks after ABMI therapy (p < .05). Significantly improved Child-Pugh scores were seen at 4 and 24 weeks (p < .05). alpha-Fetoprotein and proliferating cell nuclear antigen (PCNA) expression in liver biopsy tissue was significantly elevated after ABMI therapy (p < .05). No major adverse effects were noted. In conclusion, ABMI therapy should be considered as a novel treatment for patients with decompensated LC.

Proteomic analysis of serum marker proteins in recipient mice with liver cirrhosis after bone marrow cell transplantation

We previously found that transplantation with bone marrow cells (BMCs) improves liver function and liver fibrosis in cirrhotic mice. In the presence of liver damage induced by carbon tetrachloride (CCl4), transplanted BMC migrated into the peri-portal region and trans-differentiated into hepatocytes that produce albumin. Thus under these conditions, BMC transplantation induces liver regeneration. Detecting serum marker proteins is important to monitor the recovery of liver function of cirrhotic mice after BMC transplantation. We therefore initially resolved proteins extracted from serum samples at 48 h after BMC transplantation by 2-DE and compared spot intensity between control and BMC groups of mice. Six protein spots increased in the BMC group compared with the control group. MS revealed that these spots comprised apolipoprotein A1 (apoA1), apolipoprotein C3 (apoC3), vitamin D-binding protein, alpha-1-antitrypsin and proteasome subunit alpha type 1. We subsequently confirmed the levels of apoA1 in serum and liver samples by immunoblotting. ApoA1 increased at early stage (48 h and 1 wk) after BMC transplantation in this mouse model of liver cirrhosis. The early elevation of apoA1 might be useful to predict liver regeneration in cirrhotic mice after BMC transplantation.