Liver stem cells

The Role of Cancer-Associated Fibroblasts in Hepatocellular Carcinoma and the Value of Traditional Chinese Medicine Treatment

Invasion and metastasis are the main reasons for the high mortality of liver cancer, which involve the interaction of tumor stromal cells and malignant cells. Cancer-associated fibroblasts (CAFs) are one of the major constituents of tumor stromal cells affecting tumor growth, invasion, and metastasis. The heterogeneous properties and sources of CAFs make both tumor-supporting and tumor-suppression effects possible. The mechanisms for CAFs in supporting hepatocellular carcinoma (HCC) progression can be categorized into upregulated aggressiveness and stemness, transformed metabolism toward glycolysis and glutamine reductive carboxylation, polarized tumor immunity toward immune escape of HCC cells, and increased angiogenesis. The tumor-suppressive effect of fibroblasts highlights the functional heterogenicity of CAF populations and provides new insights into tumor–stromal interplay mechanisms. In this review, we introduced several key inflammatory signaling pathways in the transformation of CAFs from normal stromal cells and the heterogeneous biofunctions of activated CAFs. In view of the pleiotropic regulation properties of traditional Chinese medicine (TCM) and heterogeneous effects of CAFs, we also introduced the application and values of TCM in the treatment of HCC through targeting CAFs.

Novel markers of human ovarian granulosa cell differentiation toward osteoblast lineage: A microarray approach

Under physiological conditions, human ovarian granulosa cells (GCs), are responsible for a number of processes associated with folliculogenesis and oogenesis. The primary functions of GCs in the individual phases of follicle growth are: Hormone production in response to follicle stimulating hormone (FSH), induction of ovarian follicle atresia through specific molecular markers and production of nexus cellular connections for communication with the oocyte. In recent years, interest in obtaining stem cells from particular tissues, including the ovary, has increased. Special attention has been paid to the novel properties of GCs during long-term in vitro culture. It has been demonstrated that the usually recycled material in the form of follicular fluid can be a source of cells with stem-like properties. The study group consisted of patients enrolled in the in vitro fertilization procedure. Total RNA was isolated from GCs at 4 time points (after 1, 7, 15 and 30 days of culture) and was used for microarray expression analysis (Affymetrix^® Human HgU 219 Array). The expression of 22,480 transcripts was examined. The selection of significantly altered genes was based on a P-value <0.05 and expression higher than two-fold. The leucine rich repeat containing 17, collagen type I α1 chain, bone morphogenetic protein 4, twist family bHLH transcription factor 1, insulin like growth factor binding protein 5, GLI family zinc finger 2 and collagen triple helix repeat containing genes exhibited the highest changes in expression. Reverse-transcription-quantitative PCR was performed to validate the results obtained in the analysis of expression microarrays. The direction of expression changes was validated in the majority of cases. The presented results indicated that GCs have the potential of cells that can differentiate towards osteoblasts in long-term in vitro culture conditions. Increased expression of genes associated with the osteogenesis process suggests a potential for uninduced change of GC properties towards the osteoblast phenotype. The present study, therefore, suggests that GCs may become an excellent starting material in obtaining stable osteoblast cultures. GCs differentiated towards osteoblasts may be used in regenerative and reconstructive medicine in the future.

Mesenchymal Stem Cells in the Adult Human Liver: Hype or Hope?

Chronic liver diseases constitute a significant economic, social, and biomedical burden. Among commonly adopted approaches, only organ transplantation can radically help patients with end-stage liver pathologies. Cell therapy with hepatocytes as a treatment for chronic liver disease has demonstrated promising results. However, quality human hepatocytes are in short supply. Stem/progenitor cells capable of differentiating into functionally active hepatocytes provide an attractive alternative approach to cell therapy for liver diseases, as well as to liver-tissue engineering, drug screening, and basic research. The application of methods generally used to isolate mesenchymal stem cells (MSCs) and maintain them in culture to human liver tissue provides cells, designated here as liver MSCs. They have much in common with MSCs from other tissues, but differ in two aspects-expression of a range of hepatocyte-specific genes and, possibly, inherent commitment to hepatogenic differentiation. The aim of this review is to analyze data regarding liver MSCs, probably another type of liver stem/progenitor cells different from hepatic stellate cells or so-called hepatic progenitor cells. The review presents an analysis of the phenotypic characteristics of liver MSCs, their differentiation and therapeutic potential, methods for isolating these cells from human liver, and discusses issues of their origin and heterogeneity. Human liver MSCs are a fascinating object of fundamental research with a potential for important practical applications.

Exosomes from mesenchymal stem cells induce the conversion of hepatocytes into progenitor oval cells

Background

We previously reported that mesenchymal stem cells (MSCs) possess therapeutic effects in a murine model of carbon tetrachloride-induced acute liver failure. In the study, we observed that the majority of repopulated hepatocytes were of recipient origin and were adjacent to transplanted MSCs; only a low percentage of repopulated hepatocytes were from transplanted MSCs. The findings indicate that MSCs guided the formation of new hepatocytes. Exosomes are important messengers for paracrine signaling delivery. The aim of this study is to investigate the paracrine effects, in particular, the effects of exosomes from MSCs, on hepatocytes.

Methods

Mature hepatocytes were isolated from murine liver by a two-step perfusion method with collagenase digestion. MSCs were obtained from murine bone marrow, and conditioned medium (CM) from MSC culture was then collected. Time-lapse imaging was used for observation of cell morphological change induced by CM on hepatocytes. In addition, expression of markers for hepatic progenitors including oval cells, intrahepatic stem cells, and hepatoblasts were analyzed.

Results

Treatment with the CM promoted the formation of small oval cells from hepatocytes; time-lapse imaging demonstrated the change from epithelial to oval cell morphology at the single hepatocyte level. Additionally, expression of EpCAM and OC2, markers of hepatic oval cells, was upregulated. Also, the number of EpCAM^high cells was increased after CM treatment. The EpCAM^high small oval cells possessed colony-formation ability; they also expressed cytokeratin 18 and were able to store glycogen upon induction of hepatic differentiation. Furthermore, exosomes from MSC-CM could induce the conversion of mature hepatocytes to EpCAM^high small oval cells.

Conclusions

In summary, paracrine signaling through exosomes from MSCs induce the conversion of hepatocytes into hepatic oval cells, a mechanism of action which has not been reported regarding the therapeutic potentials of MSCs in liver regeneration. Exosomes from MSCs may therefore be used to treat liver diseases. Further studies are required for proof of concept of this approach.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0560-z) contains supplementary material, which is available to authorized users.

Drug-induced Liver injury Caused by Ipragliflozin Administration with Causality Established by a Positive Lymphocyte Transformation Test (LTT) and the Roussel Uclaf Causality Assessment Method (RUCAM): A Case Report

A 75-year old male patient had been regularly visiting our hospital for the management of his type 2 diabetes mellitus since he was diagnosed at age 64 years. When he developed hypoglycemic episodes with sulfonylurea, ipragliflozin (50 mg/day) was started to replace the sulfonylurea therapy. However, 49 days after starting ipragliflozin, his AST increased from 13 to 622 U/L, ALT increased from 9 to 266 U/L, ALP increased from 239 to 752 U/L, and (Υ-GTP) increased from 19 to 176 U/L. ZTT was 3.5 U, TTT was 0.4 U, and total bilirubin was 0.7 mg/dL. IgM hepatitis A antibody, hepatitis B antigen, hepatitis C virus antibody, IgM CMV antibody, and IgM EB VCA antibody were negative, whereas a lymphocyte transformation test for ipragliflozin was positive. Abdominal CT scan showed mild fatty liver but no sign of nodular lesions. Following admission to our hospital, he received liver supportive therapy with the discontinuation of ipragliflozin therapy. He was discharged from the hospital 18 days later with AST and ALT levels reduced to 20 U/L and 13 U/L, respectively. Based on the clinical presentation of this patient, it is highly important to monitor liver function along with other possible clinical complications (e.g., dehydration, ketosis, and urinary tract infection) associated with SGLT2 inhibitortherapy.

Propitious role of bone marrow-derived mononuclear cells in an experimental bile duct ligation model: potential clinical implications in obstructive cholangiopathy

PURPOSE

To evaluate the role of bone marrow-derived mononuclear cells (BMC) in rat bile duct ligation (BDL) model.

METHODS

Wistar rats were categorized into four Groups A-D. Normal liver biopsy was taken from Group A. BDL model was created in Groups B and C (15 each). Normal saline and BMC were injected through portal vein (PV) in Groups B and C, respectively. In Group D (healthy rat), only BMC were infused through PV. Groups B and C were compared for body weight, liver functions, survival, and histopathological changes.

RESULTS

Serum bilirubin was lower in Group C at day 6 (p = 0.0010). Median survival time was 5 (4, 6) and 13 (9, 17) days in Groups B and C (p = 0.0147), respectively. Portal edema (p = 0.013) and portal inflammation (p = 0.025) were less in Group C vs Group B. On post hoc subgroup analysis of rats surviving 8-26 days, portal inflammation (p = 0.004), bile duct proliferation (p = 0.016) and portal fibrosis (p = 0.038) were less in Group C vs Group B. Hepatocyte regeneration was found in four rats in Group C. CD34-positive cells were prominent in sinusoids and portal tracts in the BDL rat model.

CONCLUSIONS

BMC have shown to delay fibrosis, facilitate hepatocyte regeneration and improve survival in an experimental BDL model, with potential clinical implication in obstructive cholangiopathy.

Liver progenitor cell interactions with the extracellular matrix

Liver progenitor cells (LPCs) are a promising source of cells to treat liver disease by cell therapy, due to their capability for self-replication and bipotentiality. In order to establish useful culture systems of LPCs and apply them to future clinical therapies, it is necessary to understand their interactions with their microenvironment and especially with the extracellular matrix (ECM). There is considerable evidence from in vivo studies that matrix proteins affect the activation, expansion, migration and differentiation of LPCs, but the information on the role that specific ECMs play in regulating LPCs in vitro is more limited. Nevertheless, current studies suggest that laminin, collagen type III, collagen type IV and hyaluronic acid help to maintain the undifferentiated phenotype of LPCs and promote their proliferation when cultured in media supplemented with growth factors chosen for LPC expansion, whereas collagen type I and fibronectin are generally associated with a differentiated phenotype under the same conditions. Experimental evidence suggests that α6β1 and α5β1 integrins as well as CD44 on the surface of LPCs, and their related downstream signals, are important mediators of interactions between LPCs and the ECM. The interactions of LPCs with the ECM form the focus of this review and the contribution of ECM molecules to strategies for optimizing in vitro LPC cultures for therapeutic applications is discussed.

Foxl1-Cre-marked adult hepatic progenitors have clonogenic and bilineage differentiation potential

Isolation of hepatic progenitor cells is a promising approach for cell replacement therapy of chronic liver disease. The winged helix transcription factor Foxl1 is a marker for progenitor cells and their descendants in the mouse liver in vivo. Here, we purify progenitor cells from Foxl1-Cre; RosaYFP mice and evaluate their proliferative and differentiation potential in vitro. Treatment of Foxl1-Cre; RosaYFP mice with a 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet led to an increase of the percentage of YFP-labeled Foxl1(+) cells. Clonogenic assays demonstrated that up to 3.6% of Foxl1(+) cells had proliferative potential. Foxl1(+) cells differentiated into cholangiocytes and hepatocytes in vitro, depending on the culture condition employed. Microarray analyses indicated that Foxl1(+) cells express stem cell markers such as Prom1 as well as differentiation markers such as Ck19 and Hnf4a. Thus, the Foxl1-Cre; RosaYFP model allows for easy isolation of adult hepatic progenitor cells that can be expanded and differentiated in culture.

Bone marrow mononuclear stem cell infusion improves biochemical parameters and scintigraphy in infants with biliary atresia

PURPOSE

To evaluate early postoperative results in a case controlled study following clinical use of stem cells in extrahepatic biliary atresia (EHBA).

METHODS

From July 2005 to March 2008, 30 cases of suspected EHBA were divided in two groups in an intervention study. Group A received autologous mononuclear bone marrow stem cells at the time of Kasai or after Kasai. In Group B, only Kasai was performed. Liver function tests on postoperative day 7 were compared. Serum bilirubin, clinical status, hepatic scintigraphy and survival at 6 months and 1 year were compared.

RESULTS

Mean age was 136 (74-275) days in Group A and 99.7 (56-172) days in Group B. Preoperative values of serum bilirubin (SB), aspartate aminotransferase (AST), alanine aminotransferase and alkaline phosphatase (ALP) were comparable between the groups though there was significant difference in postoperative SB, AST and ALP (p = 0.014, 0.0041, 0.0005), with and without the use of stem cells. The median post stem cell SB was 6.9 (0.5-11.6) mg/dl in Group A versus 10.1 (5.6-26.3) mg/dl in Group B. Median SB at 6 months follow-up was 0.6 (0.5-5.4) mg/dl in Group A versus 7.6 (0.8-9.2) mg/dl in Group B (p = 0.028). There was a significant difference in episodes of cholangitis at 6 months postoperatively between the two groups (p = 0.024). Hepatic scans done at <3 months; >3 months follow-up showed prompt excretion in 80% (4/5); 85.7% (6/7) in Group A versus 20% (1/5); 50% (1/2) in Group B. Survival at 6; 12 months' follow-up was 45.5%; 27.3% in Group A versus 33.3%; 6.7% in Group B. Median postoperative survival was 181 (139,223) days in Group A versus 123 (65,181) days in Group B.

CONCLUSION

Significant biochemical and scintigraphic improvement was noted following stem cell therapy in biliary atresia, probably attributable to anti-inflammatory action of stem cells.

Beta-catenin signaling, liver regeneration and hepatocellular cancer: sorting the good from the bad

Among the adult organs, liver is unique for its ability to regenerate. A concerted signaling cascade enables optimum initiation of the regeneration process following insults brought about by surgery or a toxicant. Additionally, there exists a cellular redundancy, whereby a transiently amplifying progenitor population appears and expands to ensure regeneration, when differentiated cells of the liver are unable to proliferate in both experimental and clinical scenarios. One such pathway of relevance in these phenomena is Wnt/β-catenin signaling, which is activated relatively early during regeneration mostly through post-translational modifications. Once activated, β-catenin signaling drives the expression of target genes that are critical for cell cycle progression and contribute to initiation of the regeneration process. The role and regulation of Wnt/β-catenin signaling is now documented in rats, mice, zebrafish and patients. More recently, a regenerative advantage of the livers in β-catenin overexpressing mice was reported, as was also the case after exogenous Wnt-1 delivery to the liver paving the way for assessing means to stimulate the pathway for therapeutics in liver failure. β-Catenin is also pertinent in hepatic oval cell activation and differentiation. However, aberrant activation of the Wnt/β-catenin signaling is reported in a significant subset of hepatocellular cancers (HCC). While many mechanisms of such activation have been reported, the most functional means of aberrant and sustained activation is through mutations in the β-catenin gene or in AXIN1/2, which encodes for a scaffolding protein critical for β-catenin degradation. Intriguingly, in experimental models hepatic overexpression of normal or mutant β-catenin is insufficient for tumorigenesis. In fact β-catenin loss promoted chemical carcinogenesis in the liver due to alternate mechanisms. Since most HCC occur in the backdrop of chronic hepatic injury, where hepatic regeneration is necessary for maintenance of liver function, but at the same time serves as the basis of dysplastic changes, this Promethean attribute exhibits a Jekyll and Hyde behavior that makes distinguishing good regeneration from bad regeneration essential for targeting selective molecular pathways as personalized medicine becomes a norm in clinical practice. Could β-catenin signaling be one such pathway that may be redundant in regeneration and indispensible in HCC in a subset of cases?

Differentiated human adipose-derived stem cells exhibit hepatogenic capability in vitro and in vivo

The availability of suitable human livers for transplantation falls short of the number of potential patients. In addition, the availability of primary human hepatocytes for cell-therapy and drug development applications is significantly limited; less than 700 livers per year are available for such studies. However, the majority of these organs cannot be utilized due to pathological infections (e.g., HepB, HepC, or HIV) or excessive levels of steatosis. Thus, the number of cells needed for cell therapy applications far exceeds the number of cells available from donated livers. The ability to implant progenitor cell populations that can form liver tissue in situ, or can be differentiated in vitro would be a major advance in current cell-based therapies. In addition, and importantly for this application, the ability to utilize a non-hepatic progenitor cell to mimic hepatocytes in vitro would enable the scale-up production of cells for bioartifical liver assist devices, cell-therapy and drug discovery applications. We demonstrate the feasibility of inducing adipose-derived stromal (ASC) cells to express several features of human hepatocytes such as glycogen storage and expression of liver specific genes. Importantly, we also show that undifferentiated ASCs and ASC-derived hepatic cells engraft robustly into the liver in a mouse model of toxic injury. These data indicate a significant potential for the use of undifferentiated ASCs and ASC-derived hepatic cells as novel and valuable products for cell therapy.

Stem cell factor and c-kit are involved in hepatic recovery after acetaminophen-induced liver injury in mice

Stem cell factor (SCF) and its receptor c-kit are important in hematopoiesis and cellular proliferation. c-kit has also been identified as a cell surface marker for progenitor cells. We have previously shown that there is a large reservoir of hepatic SCF, and this molecule plays a significant role in liver regeneration after 70% hepatectomy. In the current study, we further examined the expression of SCF and c-kit in acetaminophen (APAP)-induced liver injury in C57BL/6J mice or SCF-deficient sl-sld mice and their appropriate wild-type controls. Following APAP-induced liver injury, c-kit mRNA expression increased, with peak levels detected 48 h postinjury. Hepatic SCF mRNA levels after APAP injury were also increased, with peak levels seen 16 h post-APAP. The mortality rate in SCF-deficient mice treated with APAP was significantly higher than that of wild-type mice; furthermore, administration of exogenous SCF significantly reduced the mortality of APAP-treated wild-type mice. Bromodeoxyuridine incorporation experiments showed that SCF significantly increased hepatocyte proliferation at 48 and 72 h in APAP-treated mice. SCF inhibited APAP-induced hepatocyte apoptosis and increased Bcl-2 and Bcl-xL expression, suggesting that this decrease in hepatocyte apoptosis is mediated through Bcl-2 and Bcl-xL. In summary, SCF and c-kit expression was increased after APAP-induced liver injury. Administration of exogenous SCF reduces mortality in APAP-treated mice, increases hepatocyte proliferation, and prevents hepatocyte apoptosis induced by APAP, suggesting that these molecules are important in the liver's recovery from these injuries.

A novel role for proteomics in the discovery of cell-surface markers on stem cells: Scratching the surface

The concept of cell-based therapy has been advocated as a novel approach for treating diseases or conditions where regeneration of cells, tissue and/or potentially organs is required. A promising source for cell-replacement therapies is provided by stem cells, but the success of this approach will ultimately rely on the ability to isolate primary stem or progenitor cells. Cell-surface protein markers will play a critical role in this step. Current methodologies for the identification of cell-surface protein markers rely primarily on antibody availability and flow cytometry, but many cell-surface proteins remain undetectable. Proteomic technologies now offer the possibility to specifically identify and investigate the cell-surface subproteome in a quantitative and discovery-driven manner. Once a cell surface protein marker panel has been identified by MS and the antibodies become available, the panel should permit the identification, tracking, and/or isolation of stem or progenitor cells that may be appropriate for therapeutics. This review provides a context for the use of proteomics in discovering new cell-surface markers for stem cells.

Restoring the function of salivary glands

Salivary gland destruction occurs as a result of various pathological conditions such as radiation therapy for head and neck cancer and Sjögren's syndrome. As saliva possesses self-cleaning and antibacterial capability, hyposalivation is known to deteriorate dental caries and periodontal disease. Furthermore, hyposalivation causes mastication and swallowing problems, burning sensation of the mouth and dysgeusia. Currently available treatments for dry mouth are prescription for artificial saliva, moisturizers and medications which induce salivation from the residual tissue. Unfortunately, these treatments cannot restore the acini functions. This review focuses on various efforts to restore the function of damaged salivary gland. First, the possibility of salivary gland regeneration and tissue engineering is discussed with reference to stem cells, growth factors and scaffold materials. Second, the current status of gene transfer to salivary glands is discussed.

Expressions of cytokeratin 18 and cytokeratin 19 in hepatocellular carcinoma tissues

AIM: To observe the expressions of cytoketatin18 (CK18) and cytoketatin19 (CK19) in tissues of hepatocellular carcinoma, liver cirrhosis, and normal liver.

METHODS: Immunohistochemical streptavidin-peroxidase (SP) method was adopted to examine the expression of CK18 and CK19 in tissue samples of normal liver (n = 8), liver cirrhosis (n = 27), and hepatocellular carcinoma (n = 43).

RESULTS: The positive rates of CK18 expression in hepatic cirrhosis and normal liver tissues had no significant differences. However, CK18 expression was significantly different between hepatocellular carcinoma and liver cirrhosis (65.1% vs 29.6%, P < 0.01). The positive rates of CK19 expression in cirrhosis of liver and normal liver had no significant differences. But the expression of CK19 was markedly higher in hepatocellular carcinoma than that in hepatic cirrhosis (69.8% vs 25.9%, P < 0.01). Oval cells with strongly positive staining could be seen in the portal area of cirrhosis cases (20/27) and in the brink of carcinoma cases (35/43), and there were significant differences (CK18: 6.57 ± 1.69 vs 10.70 ± 2.31; CK19: 5.37 ± 1.17 vs 10.45 ± 2.15, P < 0.01) in the numbers between cirrhosis of liver and hepatocellular carcinoma.

CONCLUSION: CK18 and CK19 are involved in hepatocarcinogenesis. Oval cells are strongly positive for CK18 and CK19 in cirrhosis of liver and hepatocellular carcinoma. Oval cells are associated with regeneration of liver, and are probably original cells of hepatocellular carcinoma.

Translational control plays a prominent role in the hepatocytic differentiation of HepaRG liver progenitor cells

BACKGROUND

We investigated the molecular events associated with the differentiation of liver progenitor cells into functional and polarized hepatocytes, using human HepaRG cells that display potent hepatocytic differentiation-inducible properties and share some features with liver progenitor cells.

RESULTS

Profiling of total and of polysome-bound transcripts isolated from HepaRG cells undergoing hepatocytic differentiation was performed. A group of 3,071 probe sets was reproducibly regulated by at least 2-fold in total or in polysome-bound RNA populations, upon differentiation. The fold changes in the total and the polysome-bound RNA populations for these 3,071 probe sets were poorly correlated (R = 0.38). Moreover, while the majority of the regulated polysome-bound RNA probe sets were up-regulated upon differentiation, the majority of the regulated probe sets selected from the total RNA population was down-regulated. Genes translationally up-regulated were associated with cell cycle inhibition, increased susceptibility to apoptosis and innate immunity. In contrast, genes transcriptionally up-regulated during differentiation corresponded in the majority to liver-enriched transcripts involved in lipid homeostasis and drug metabolism. Finally, several epithelial and hepato-specific transcripts were strongly induced in the total RNA population but were translationally repressed.

CONCLUSION

Translational regulation is the main genomic event associated with hepatocytic differentiation of liver progenitor cells in vitro and targets genes critical for moderating hepatocellular growth, cell death and susceptibility to pathogens. Transcriptional regulation targets specifically liver-enriched transcripts vital for establishing normal hepatic energy homeostasis, cell morphology and polarization. The hepatocytic differentiation is also accompanied by a reduction of the transcript content complexity.

Mammalian target of rapamycin activation impairs hepatocytic differentiation and targets genes moderating lipid homeostasis and hepatocellular growth

The mammalian target of rapamycin (mTOR) pathway, a major regulator of translation, is frequently activated in hepatocellular carcinomas. We investigated the effects of mTOR activation in the human HepaRG cells, which possess potent hepatocytic differentiation capability. Differentiation of HepaRG cells into functional and polarized hepatocyte-like cells correlated with a decrease in mTOR and Akt activities. Stable cell lines expressing an activated mutant of mTOR were generated. Sustained activation of mTOR impaired the hepatocytic differentiation capability of these cells as shown by impaired formation of bile canaliculi, absence of polarity, and reduced secretion of alpha1-antitrypsin. An inhibitor of mTOR, rapamycin, was able to revert this phenotype. Furthermore, increased mTOR activity in HepaRG cells resulted in their resistance to the antiproliferative effects of transforming growth factor-beta1. Profiling of polysome-bound transcripts indicated that activated mTOR specifically targeted genes posttranscriptionally regulated on hepatocytic differentiation. Three major biological networks targeted by activated mTOR were identified: (a) cell death associated with tumor necrosis factor superfamily members, IFNs and caspases; (b) lipid homeostasis associated with the transcription factors PPARalpha, PPARdelta, and retinoid X receptor beta; and (c) liver development associated with CCAAT/enhancer binding protein alpha and hepatic mitogens. In conclusion, increased mTOR activity conferred a preneoplastic phenotype to the HepaRG cells by altering the translation of genes vital for establishing normal hepatic energy homeostasis and moderating hepatocellular growth.

Differentiation of neonatal rat epithelial cells from biliary origin into immature hepatic cells by sequential exposure to hepatogenic cytokines and growth factors reflecting liver development

It was investigated whether cryopreserved rat liver epithelial cells (RLEC) from biliary origin are capable of undergoing hepatic differentiation upon sequential exposure to liver-specific factors (fibroblast growth factor (FGF)-4, hepatocyte growth factor (HGF), insulin-transferrin-sodium-selenite (ITS), dexamethasone (Dex) and oncostatin M (OSM)), reflecting liver embryogenesis in vivo. As differentiation progressed, cells acquired a hepatic morphology (polygonal-to-cuboidal shaped, binucleated cells), corresponding well with the phenotypic changes observed. Biliary cytokeratin (CK)19 and connexin (Cx)43-expression both gradually decreased; CK19-expression disappeared even completely. In contrast, hepatic CK18-expression persisted throughout the culture time. Hepatocyte nuclear factor (HNF)3beta, alpha-foetoprotein (AFP), transthyretin (TTR), HNF4, albumin (ALB), HNF1alpha, multidrug resistance protein (MRP)2 and Cx32 were expressed at specific stages during RLEC-differentiation, thereby showing a progressive hepatic maturation. Indeed, immature AFP and mature ALB were sequentially expressed, in line with the in vivo liver embryogenesis. Expression of the early and mid-late 'liver-enriched' transcription factors (LETF) HNF3beta and HNF4 declined and translocated to the cytosol, respectively, while the late LETF HNF1alpha underwent a nuclear upregulation. In conclusion, RLEC are bipotent cells, capable of differentiation into immature hepatocytes in a hepatic-stimulating micro-environment. The robustness of the sequential conditions, developed before for hepatic 'transdifferentiation' of rat bone marrow stem cells (rBMSC), was hereby confirmed.

Stem Cells as a Therapeutic Modality in Pediatric Malformations

AIM

The aim of this study was to explore stem cell use in congenital anomalies.

PATIENTS AND METHODS

During July 2005 through July 2006, autologous stem cells were used in 29 patients: 12 with liver cirrhosis and 17 with meningomyelocele. Stem cells were injected into the hepatic artery and the portal vein or into the hepatobiliary radicals for liver cirrhosis, or into the spinal cord and caudal space for meningomyelocele. Preoperative status served as the control condition.

OBSERVATIONS AND RESULTS

The ages of patients with liver cirrhosis ranged between 1.5 and 9 months (mean, 4.12 months). The etiology was extra hepatic biliary atresia (EHBA) versus neonatal cholestasis and choledochal cyst in 8; 2 and 2 patients, respectively. Five patients died due to ongoing cirrhosis. Follow-up at 3 to 12 months (N = 7) showed absence of cholangitis (4/7), yellow stools (5/7), decreased liver firmness (3/7), improved liver function (6/7), and better appetite (6/7). Hepatobiliary scan was excretory in 6 of 7 with improved uptake in 4 of 7. Histopathology demonstrated comparative improvement in fibrosis among 3 patients. Meningomyelocele patients were between 0 and 1 month, 1-5 months, and 1-4 years in 5, 8, and 2 cases respectively. Five had a history of rupture. Three had undergone meningocele repair in the past with neurological deficits. Redo surgery for a tethered cord was performed in 1 patient. Follow-up at 3 to 11 months in 14 cases showed improved power in 7 with dramatic recovery in 3 (22%) and status quo in 7 (50%).

CONCLUSION

Initial stem cell use in liver cirrhosis and meningomyelocele has suggested beneficial results. However, long-term evaluation in randomized controlled trials is essential to draw further conclusions.

Small human hepatocytes in rotary culture for treatment of alcohol addicts? A pilot study

BACKGROUND

Current approaches to support alcohol addict and/or benzodiazepine-treated patients with liver failure include culturing human cells to take over basic metabolic functions for a certain time.

METHODS

Small human hepatocytes (SH) were grown in a rotary cell culture system, and their potential to metabolize alcohol and the benzodiazepines oxazepam and diazepam was evaluated. Control experiments were performed with SV40-immortalized HEP cells and cell respective drug-free media.

RESULTS

Our results show that SH in rotary culture are able to metabolize ethanol in reasonable amounts compared with evaporation controls (p<0.01). Moreover, SH are also able to metabolize oxazepam and diazepam which proves their ability to perform conjugation and the presence of functional cytochrome P450 enzymes. Basic metabolic activities such as glucose consumption, albumin and urea production are not significantly influenced by the drugs used, which is a precondition for clinical use of these cells. Significantly increased lactate dehydrogenase release indicates enhanced cell death in cultures of SH incubated with either ethanol (p<0.05) or diazepam (p<0.005), but stable viability at or above 90% suggests that cell proliferation is able to keep up with drug-induced cell death.

CONCLUSION

Our preliminary study provides evidence that SH are basically suited to support alcohol-abusing and/or benzodiazepine-treated patients undergoing liver failure.