Histological improvement following administration of autologous bone marrow-derived mesenchymal stem cells for alcoholic cirrhosis: a pilot study

Progress in stem cell-based therapy for liver disease

Liver transplantation has been accepted as a useful therapeutic approach for patients with end-stage liver disease. However, the mismatch between the great demand for liver transplants and the number of available donor organs underscores the urgent need for alternative therapeutic strategies for patients with acute and chronic liver failure. The rapidly growing knowledge on stem cell biology has opened new avenues toward stem cell-based therapy for liver disease. As stem cells have capacity for high proliferation and multipotent differentiation, the characteristics of stem cells fit the cell therapy. Several types of cells have been investigated as possible sources of liver regeneration: mesenchymal stem cells, hematopoietic stem cells, liver progenitor cells, induced pluripotent stem cells, and bone marrow mononuclear cells. In vitro and in vivo experiments revealed that these cells have great potential as candidates of stem cell therapy. We reviewed the reports on clinical trials of cell therapy for liver disease that have been recently undertaken using mesenchymal stem cells, hematopoietic stem cells, bone marrow mononuclear cells, and liver progenitor cells. These reports have heterogeneity of description of trial design, types of infused cells, patient population, and efficacy of therapies. We addressed these reports from these viewpoints and clarified their significance. We hope that this review article will provide a perspective on the available approaches based on stem cell-based therapy for liver disease.

Long-Term Follow-Up of Patients After Autologous Bone Marrow Cell Infusion for Decompensated Liver Cirrhosis

Although several human clinical trials using various bone marrow-derived cell types for cirrhotic or decompensated patients have reported a short-term benefit, long-term follow-up data are limited. We analyzed the long-term clinical outcomes of autologous bone marrow cell infusion (ABMI) for decompensated liver cirrhosis (LC). Patients enrolled in a pilot single-armed ABMI study were followed up more than 5 years. Bone marrow-derived mononuclear cells (BM-MNCs) from decompensated LC were harvested and after processing were infused into a peripheral vein. The laboratory test results and long-term clinical course including liver transplantation (LT), development of cancer, cause of death, and survival after ABMI were analyzed. Nineteen patients were followed up for a median of 66 months after ABMI. Liver function, including serum levels of albumin and Child-Pugh (CP) score, was improved at the 1-year follow-up. Liver volume was significantly greater, cirrhosis was sustained, and collagen content was decreased at the 6-month follow-up. Five years after ABMI, five patients (26.3%) maintained CP class A without LT or death, and five patients (26.3%) had undergone elective LT. Hepatocellular carcinoma (HCC) occurred in five patients (26.3%), and lymphoma and colon cancer occurred in one patient each. Three patients (15.8%) were lost to follow-up at months 22, 31, and 33, respectively, but maintained CP class A until their last follow-up. Five patients expired due to infection. While improved liver function was maintained in some patients for more than 5 years after ABMI, other patients developed HCC. Further studies of long-term follow-up cohorts after cell therapy for LC are warranted.

Cell transplantation as a non-invasive strategy for treating liver fibrosis

Advancements in antiviral drugs have enabled control of viral hepatitis; yet, many patients with liver cirrhosis (LC) are awaiting liver transplants. Liver transplantation yields dramatic therapeutic effects, but problems such as shortage of donors, surgical invasiveness, immunological rejection and costs, limit the number of transplantations. Advances in liver regeneration therapy through cell transplantation as a non-invasive treatment for cirrhosis will supplement these restrictions to the number of liver transplants. Clinical trials for LC have included hematopoietic stem cell mobilization by administration of granulocyte colony-stimulating factor, infusion of autologous bone marrow cells, and administration of autologous mesenchymal stem cells derived from bone marrow or umbilical cord. Several recently reported randomized controlled studies have shown the effectiveness of these approaches. However, to promote implementation of new liver regeneration therapies, it is important to develop a system whereby cell therapies with ensured safety can be approved quickly.

Transplantation with autologous bone marrow-derived mesenchymal stem cells for alcoholic cirrhosis: Phase 2 trial

Bone marrow-derived mesenchymal stem cell (BM-MSC) transplantation has been suggested as an effective therapy for liver cirrhosis. The efficacy and safety of autologous BM-MSC transplantation in the treatment of alcoholic cirrhosis were investigated. Seventy-two patients with baseline biopsy-proven alcoholic cirrhosis who had been alcohol-abstinent for more than 6 months underwent a multicenter, randomized, open-label, phase 2 trial. Patients were randomly assigned to three groups: one control group and two autologous BM-MSC groups that underwent either one-time or two-time hepatic arterial injections of 5 × 10⁷ BM-MSCs 30 days after BM aspiration. A follow-up biopsy was performed 6 months after enrollment, and adverse events were monitored for 12 months. The primary endpoint was improvement in fibrosis quantification based on picrosirius red staining. The secondary endpoints included liver function tests, Child-Pugh score, and Model for End-stage Liver Disease score. Outcomes were analyzed by per-protocol analysis. In terms of fibrosis quantification (before versus after), the one-time and two-time BM-MSC groups were associated with 25% (19.5 ± 9.5% versus 14.5 ± 7.1%) and 37% (21.1 ± 8.9% versus 13.2 ± 6.7%) reductions in the proportion of collagen, respectively (P < 0.001). In the intergroup comparison, two-time BM-MSC transplantation in comparison with one-time BM-MSC transplantation was not associated with improved results in fibrosis quantification (P > 0.05). The Child-Pugh scores of both BM-MSC groups (one-time 7.6 ± 1.0 versus 6.3 ± 1.3 and two-time 7.8 ± 1.2 versus 6.8 ± 1.6) were also significantly improved following BM-MSC transplantation (P < 0.05). The proportion of patients with adverse events did not differ among the three groups.

CONCLUSION

Autologous BM-MSC transplantation safely improved histologic fibrosis and liver function in patients with alcoholic cirrhosis. (Hepatology 2016;64:2185-2197).

Effect of undifferentiated versus hepatogenic partially differentiated mesenchymal stem cells on hepatic and cognitive functions in liver cirrhosis

Liver cirrhosis is the outcome of chronic liver injury. The current study aimed to investigate the therapeutic effect of undifferentiated mesenchymal stem cells versus in vitro partially differentiated mesenchymal stem cells on liver cirrhosis and hepatic encephalopathy. 50 adult male albino rats constituted the animal model and were divided into the following groups: control, thioacetamide, undifferentiated mesenchymal stem cells and hepatocyte growth factor-differentiated mesenchymal stem cells groups. Cognitive assessment was achieved by open field test and Y-maze task. We measured serum alanine aminotransferase, albumin and transforming growth factor-beta1, gene expression of α-smooth muscle actin, matrix metalloprotein-2, its tissue inhibitor and apoptotic markers: Bax and Bcl2, brain glial fibrillary acidic protein, synaptophysin, and dopaminergic receptors.

Adipose Tissue and Mesenchymal Stem Cells: State of the Art and Lipogems® Technology Development

In the past few years, interest in adipose tissue as an ideal source of mesenchymal stem cells (MSCs) has increased. These cells are multipotent and may differentiate in vitro into several cellular lineages, such as adipocytes, chondrocytes, osteoblasts, and myoblasts. In addition, they secrete many bioactive molecules and thus are considered “mini-drugstores.” MSCs are being used increasingly for many clinical applications, such as orthopedic, plastic, and reconstructive surgery. Adipose-derived MSCs are routinely obtained enzymatically from fat lipoaspirate as SVF and/or may undergo prolonged ex vivo expansion, with significant senescence and a decrease in multipotency, leading to unsatisfactory clinical results. Moreover, these techniques are hampered by complex regulatory issues. Therefore, an innovative technique (Lipogems®; Lipogems International SpA, Milan, Italy) was developed to obtain microfragmented adipose tissue with an intact stromal vascular niche and MSCs with a high regenerative capacity. The Lipogems® technology, patented in 2010 and clinically available since 2013, is an easy-to-use system designed to harvest, process, and inject refined fat tissue and is characterized by optimal handling ability and a great regenerative potential based on adipose-derived MSCs. In this novel technology, the adipose tissue is washed, emulsified, and rinsed and adipose cluster dimensions gradually are reduced to about 0.3 to 0.8 mm. In the resulting Lipogems® product, pericytes are retained within an intact stromal vascular niche and are ready to interact with the recipient tissue after transplantation, thereby becoming MSCs and starting the regenerative process. Lipogems® has been used in more than 7000 patients worldwide in aesthetic medicine and surgery, as well as in orthopedic and general surgery, with remarkable and promising results and seemingly no drawbacks. Now, several clinical trials are under way to support the initial encouraging outcomes. Lipogems® technology is emerging as a valid intraoperative system to obtain an optimal final product that may be used immediately for regenerative purposes.

Effect of Function-Enhanced Mesenchymal Stem Cells Infected With Decorin-Expressing Adenovirus on Hepatic Fibrosis

: Bone marrow-derived mesenchymal stem cells (BM-MSCs) are known to have an antifibrotic effect and could be used as vehicles for targeted gene delivery. Decorin plays a protective role against fibrogenesis by modulating the degradation of the extracellular matrix. The aim of this study was to determine whether the antifibrotic effect of a combination treatment consisting of BM-MSCs and decorin on hepatic fibrosis is superior to BM-MSCs alone. The effects of BM-MSCs infected with decorin-expressing adenovirus (DCN-MSCs) on hepatic fibrosis were examined in a rat model of thioacetamide (TAA)-induced cirrhosis. The effects of infection with decorin-expressing adenovirus and of incubation with the conditioned medium of DCN-MSCs on transforming growth factor-β (TGF-β) signaling were analyzed in immortalized human hepatic stellate cells (HSCs). According to the Laennec fibrosis scoring system, cirrhotic livers from rats treated with DCN-MSCs exhibited histological improvement compared with cirrhotic livers from rats treated with control adenovirus-infected MSCs (CA-MSCs). DCN-MSC treatment reduced hepatic collagen distribution, lowered the hydroxyproline content, and rescued liver function impairment in rats with TAA-induced cirrhosis. These protective effects were more potent with DCN-MSCs than with CA-MSCs. The upregulation of collagen-1, α-smooth muscle actin (α-SMA), TGF-β1, and Smad3 phosphorylation in cirrhotic livers was prevented by DCN-MSC administration. Intriguingly, medium from cultured DCN-MSCs blocked both Smad3 phosphorylation and exogenous TGF-β1 stimulated α-SMA synthesis in HSCs. DCN-MSCs exert strong protective effects against hepatic fibrosis by suppressing TGF-β/Smad signaling. Thus, treatment with DCN-MSCs is a potentially novel and efficient therapeutic approach for patients with intractable cirrhosis.

SIGNIFICANCE

A combination treatment consisting of bone marrow-derived mesenchymal stem cells (BM-MSCs) and decorin strongly inhibited the progression of thioacetamide-induced hepatic fibrosis in rats, compared with BM-MSCs alone. Furthermore, the significant inhibitory effect of BM-MSCs infected with decorin-expressing adenovirus was attributed to suppressing transforming growth factor-β (TGF-β)/Smad signaling pathway, supported by attenuation of TGF-β1 expression and inhibition of Smad3 phosphorylation. Therefore, treatment with BM-MSCs infected with decorin-expressing adenovirus could constitute a novel and efficient therapeutic approach for patients with intractable cirrhosis.

The need for histological subclassification of cirrhosis: a systematic review and meta-analysis

BACKGROUND & AIMS

The need for further histological subclassification of cirrhosis has been increasingly recognized because of the heterogeneity of severity within cirrhosis. We sought to identify evidence in the literature regarding the histological subclassification of cirrhosis using the Laennec stage.

METHODS

We conducted a systematic review and meta-analysis by searching databases, including MEDLINE, EMBASE and the COCHRANE library, for relevant studies.

RESULTS

Of 208 studies identified, 16 were eligible according to the inclusion criteria. With higher grades of the Laennec stage, clinical stages of cirrhosis and Child-Pugh scores/Model for end-stage liver disease scores increased (P < 0.05). Higher Laennec stages were statistically associated with the development of liver-related events, such as liver-related death, liver cancer progression and variceal haemorrhage, as well as higher hepatic venous pressure gradients and higher liver stiffness values (P < 0.05). Two open-labelled studies showed the usefulness of the Laennec system with regard to the evaluation of whether antifibrotic treatments were effective. The mean kappa value was 0.81 (range 0.61-0.87) for inter-observer agreement.

CONCLUSIONS

Based on this systematic review and meta-analysis, histological subclassification of cirrhosis using the Laennec system is useful to better predict prognosis and complications of portal hypertension.

Stem Cell Therapies in Clinical Trials: Progress and Challenges

Clinical investigations using stem cell products in regenerative medicine are addressing a wide spectrum of conditions using a variety of stem cell types. To date, there have been few reports of safety issues arising from autologous or allogeneic transplants. Many cells administered show transient presence for a few days with trophic influences on immune or inflammatory responses. Limbal stem cells have been registered as a product for eye burns in Europe and mesenchymal stem cells have been approved for pediatric graft versus host disease in Canada and New Zealand. Many other applications are progressing in trials, some with early benefits to patients.

Mesenchymal Stem/Stromal Cells in Liver Fibrosis: Recent Findings, Old/New Caveats and Future Perspectives

Mesenchymal stem/stromal cells (MSCs) are progenitors which share plastic-adherence capacity and cell surface markers but have different properties according to their cell and tissue sources and to culture conditions applied. Many recent publications suggest that MSCs can differentiate into hepatic-like cells, which can be a consequence of either a positive selection of rare in vivo pluripotent cells or of the original plasticity of some cells contributing to MSC cultures. A possible role of MSCs in hereditary transmission of obesity and/or diabetes as well as properties of MSCs regarding immunomodulation, cell fusion and exosome release capacities are discussed according to recent literature. Limitations in methods used to track MSCs in vivo especially in the context of liver cirrhosis are addressed as well as strategies explored to enhance their migratory, survival and proliferation properties, which are known to be relevant for their future clinical use. Current knowledge regarding mechanisms involved in liver cirrhosis amelioration mediated by naïve and genetically modified MSCs as well as the effects of applying preconditioning and combined strategies to improve their therapeutic effects are evaluated. Finally, first reports of GMP guidelines and biosafety issues in MSCs applications are discussed.

Ex Vivo Stromal Cell-Derived Factor 1-Mediated Differentiation of Mouse Bone Marrow Mesenchymal Stem Cells into Hepatocytes Is Enhanced by Chinese Medicine Yiguanjian Drug-Containing Serum

Yiguanjian is administered in traditional Chinese medicine for liver diseases and has been demonstrated to reduce liver fibrosis. This study investigated the effect of Yiguanjian drug-containing serum (YGJ) with Stromal Cell-Derived Factor 1 (SDF-1) and Hepatocyte Growth Factor (HGF) on the differentiation of murine bone-marrow-derived mesenchymal cells (BM-MSCs) into hepatocytes in vitro. Adherent MSCs were isolated from murine bone marrow. Differentiation was induced by 20 ng/mL HGF, 50 ng/mL SDF-1, and 20% Yiguanjian drug-containing serum for 7 to 28 days, and mature hepatocytes' marker albumin (ALB) and cholangiocytes' marker cytokeratin-18 (CK-18) were assessed by immunocytochemistry and western blot. BM-MSCs exhibited homogeneous spindle shape growth after subculture and stained positive for CD90 and negative for CD34. After induction with HGF + normal serum or YGJ for 14 days, HGF + SDF-1 + normal serum for 7 days, or HGF + SDF-1 + YGJ for 5 days, MSCs' morphology changed gradually and begun to resemble hepatocyte-like cells. Cultures supplemented with HGF + SDF-1 + YGJ contained significantly higher proportions of ALB and CK-18 positive cells than cultures supplemented with HGF + SDF-1 + normal serum at day 7. These observations corroborated the results of western blot. In conclusion, Yiguanjian drug-containing serum could facilitate the differentiation of murine BM-MSCs into hepatocytes in vitro and has a synergistic effect with SDF-1 and HGF.

Stem Cell Therapy: Current Applications and Potential for Urology

Stem cell therapy holds the potential to revolutionize the treatment of a number of chronic conditions. Stem cells ability to home in on injured sites of the body, stimulate angiogenesis, tissue regeneration, immunomodulation, anti-inflammatory, and anti-fibrotic factors have attracted their use in the treatment of many conditions. Urology has registered one of the highest experimental successes using stem cell therapy. However, the rate of clinical applications is comparatively lower. This review takes a look at our efforts so far and what needs to be done in order to maximize the clinical benefit we can derive from stem cells.

Multipotent mesenchymal stromal cells: A promising strategy to manage alcoholic liver disease

Chronic alcohol consumption is a major cause of liver disease. The term alcoholic liver disease (ALD) refers to a spectrum of mild to severe disorders including steatosis, steatohepatitis, cirrhosis, and hepatocellular carcinoma. With limited therapeutic options, stem cell therapy offers significant potential for these patients. In this article, we review the pathophysiologic features of ALD and the therapeutic mechanisms of multipotent mesenchymal stromal cells, also referred to as mesenchymal stem cells (MSCs), based on their potential to differentiate into hepatocytes, their immunomodulatory properties, their potential to promote residual hepatocyte regeneration, and their capacity to inhibit hepatic stellate cells. The perfect match between ALD pathogenesis and MSC therapeutic mechanisms, together with encouraging, available preclinical data, allow us to support the notion that MSC transplantation is a promising therapeutic strategy to manage ALD onset and progression.

Stem cell-based regenerative opportunities for the liver: State of the art and beyond

The existing mismatch between the great demand for liver transplants and the number of available donor organs highlights the urgent need for alternative therapeutic strategies in patients with acute or chronic liver failure. The rapidly growing knowledge on stem cell biology and the intrinsic repair processes of the liver has opened new avenues for using stem cells as a cell therapy platform in regenerative medicine for hepatic diseases. An impressive number of cell types have been investigated as sources of liver regeneration: adult and fetal liver hepatocytes, intrahepatic stem cell populations, annex stem cells, adult bone marrow-derived hematopoietic stem cells, endothelial progenitor cells, mesenchymal stromal cells, embryonic stem cells, and induced pluripotent stem cells. All these highly different cell types, used either as cell suspensions or, in combination with biomaterials as implantable liver tissue constructs, have generated great promise for liver regeneration. However, fundamental questions still need to be addressed and critical hurdles to be overcome before liver cell therapy emerges. In this review, we summarize the state-of-the-art in the field of stem cell-based therapies for the liver along with existing challenges and future perspectives towards a successful liver cell therapy that will ultimately deliver its demanding goals.

Three-dimensional co-culture of human hepatocytes and mesenchymal stem cells: improved functionality in long-term bioreactor cultures

The development of human cell models that can efficiently restore hepatic functionality and cope with the reproducibility and scalability required for preclinical development poses a significant effort in tissue engineering and biotechnology. Primary cultures of human hepatocytes (HHs), the preferred model for in vitro toxicity testing, dedifferentiate and have short-term viability in two-dimensional (2D) cultures. In this study, hepatocytes isolated from human liver tissue were co-cultured with human bone marrow mesenchymal stem cells (BM-MSCs) as spheroids in automated, computer-controlled, stirred-tank bioreactors with perfusion operation mode. A dual-step inoculation strategy was used, resulting in an inner core of parenchymal liver tissue with an outer layer of stromal cells. Hepatocyte polarization and morphology as well as the mesenchymal phenotype of BM-MSCs were maintained throughout the culture period and the crosstalk between the two cell types was depicted. The viability, compact morphology and phenotypic stability of hepatocytes were enhanced in co-cultures in comparison to monocultures. Gene expression of phase I and II enzymes was higher and CYP3A4 and CYP1A2 activity was inducible until week 2 of culture, being applicable for repeated-dose toxicity testing. Moreover, the excretory activity was maintained in co-cultures and the biosynthetic hepatocellular functions (albumin and urea secretion) were not affected by the presence of BM-MSCs. This strategy might be extended to other hepatic cell sources and the characterization performed brings knowledge on the interplay between the two cell types, which may be relevant for therapeutic applications. Copyright © 2015 John Wiley & Sons, Ltd.

Therapeutic Effects of Mesenchymal Stem Cells for Patients with Chronic Liver Diseases: Systematic Review and Meta-analysis

Based on their ability to differentiate into multiple cell types including hepatocytes, the transplantation of mesenchymal stem cells (MSCs) has been suggested as an effective therapy for chronic liver diseases. The aim of this study was to evaluate the safety, efficacy and therapeutic effects of MSCs in patients with chronic liver disease through a literature-based examination. We performed a systematic review (SR) and meta-analysis (MA) of the literature using the Ovid-MEDLINE, EMBASE and Cochrane Library databases (up to November 2014) to identify clinical studies in which patients with liver diseases were treated with MSC therapy. Of the 568 studies identified by the initial literature search, we analyzed 14 studies and 448 patients based on our selection criteria. None of the studies reported the occurrence of statistically significant adverse events, side effects or complications. The majority of the analyzed studies showed improvements in liver function, ascites and encephalopathy. In particular, an MA showed that MSC therapy improved the total bilirubin level, the serum albumin level and the Model for End-stage Liver Disease (MELD) score after MSC treatment. Based on these results, MSC transplantation is considered to be safe for the treatment of chronic liver disease. However, although MSCs are potential therapeutic agents that may improve liver function, in order to obtain meaningful insights into their clinical efficacy, further robust clinical studies must be conducted to evaluate the clinical outcomes, such as histological improvement, increased survival and reduced liver-related complications, in patients with chronic liver disease.

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.

Mesenchymal stem cell therapy for liver fibrosis

Currently, the most effective treatment for end-stage liver fibrosis is liver transplantation; however, transplantation is limited by a shortage of donor organs, surgical complications, immunological rejection, and high medical costs. Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have the potential to differentiate into hepatocytes, and therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. In addition, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis and enhance liver functionality. Despite these advantages, issues remain; MSCs also have fibrogenic potential and the capacity to promote tumor cell growth and oncogenicity. This paper summarizes the properties of MSCs for regenerative medicine and their therapeutic mechanisms and clinical application in the treatment of liver fibrosis. We also present several outstanding risks, including their fibrogenic potential and their capacity to promote pre-existing tumor cell growth and oncogenicity.

Inhibition of hepatic stellate cells by bone marrow-derived mesenchymal stem cells in hepatic fibrosis

BACKGROUND/AIMS

Therapies involving bone-marrow-derived mesenchymal stem cells (BM-MSCs) have considerable potential in the management of hepatic disease. BM-MSCs have been investigated in regenerative medicine due to their ability to secrete various growth factors and cytokines that regress hepatic fibrosis and enhance hepatocyte functionality. The aim of this study was to determine the antifibrosis effect of BM-MSCs on activated hepatic stellate cells (HSCs) and the mechanism underlying how BM-MSCs modulate the function of activated HSCs.

METHODS

We used HSCs in both direct and indirect co-culture systems with BM-MSCs to evaluate the antifibrosis effect of BM-MSCs. The cell viability and apoptosis were evaluated by a direct co-culture system of activated HSCs with BM-MSCs. The activations of both HSCs alone and HSCs with BM-MSCs in the direct co-culture system were observed by immunocytochemistry for alpha-smooth muscle actin (α-SMA). The levels of growth factors and cytokines were evaluated by an indirect co-culture system of activated HSCs with BM-MSCs.

RESULTS

The BM-MSCs in the direct co-culture system significantly decreased the production of α-SMA and the viability of activated HSCs, whereas they induced the apoptosis of activated HSCs. The BM-MSCs in the indirect co-culture system decreased the production of transforming growth factor-β1 and interleukin (IL)-6, whereas they increased the production of hepatocyte growth factor and IL-10. These results confirmed that the juxtacrine and paracrine effects of BM-MSCs can inhibit the proliferative, fibrogenic function of activated HSCs and have the potential to reverse the fibrotic process by inhibiting the production of α-SMA and inducing the apoptosis of HSCs.

CONCLUSIONS

These results have demonstrated that BM-MSCs may exert an antifibrosis effect by modulating the function of activated HSCs.

Strategies to prevent and reverse liver fibrosis in humans and laboratory animals

Liver fibrosis results from chronic damage to the liver in conjunction with various pathways and is mediated by a complex microenvironment. Based on clinical observations, it is now evident that fibrosis is a dynamic, bidirectional process with an inherent capacity for recovery and remodeling. The major mechanisms involved in liver fibrosis include the repetitive injury of hepatocytes, the activation of the inflammatory response after injury stimulation, and the activation and proliferation of hepatic stellate cells (HSCs), which represents the major extracellular matrix (ECM)-producing cells, stimulated by hepatocyte injury and inflammation. The microenvironment in the liver is synergistically regulated abnormal ECM deposition, scar formation, angiogenesis, and fibrogenesis. Moreover, recent studies have clarified novel mechanism in fibrosis such as epigenetic regulation of HSCs, the leptin and PPARγ pathways, the coagulation system, and even autophagy. Uncovering the mechanisms of liver fibrogenesis provides a basis to develop potential therapies to reverse and treat the fibrotic response, thereby improving the outcomes of patients with chronic liver disease. Although both scientific and clinical challenges remain, emerging studies attempt to reveal the ideal anti-fibrotic drug that could be easily delivered to the liver with high specificity and low toxicity. This review highlights the mechanisms, including novel pathways underlying fibrogenesis that may be translated into preventive and treatment strategies, reviews both current and novel agents that target specific pathways or multiple targets, and discusses novel drug delivery systems such as nanotechnology that can be applied in the treatment of liver fibrosis. In addition, we also discuss some current treatment strategies that are being applied in animal models and in clinical trials.

L-ascorbic acid 2-phosphate and fibroblast growth factor-2 treatment maintains differentiation potential in bone marrow-derived mesenchymal stem cells through expression of hepatocyte growth factor

l-ascorbic acid 2-phosphate (Asc-2P) acts as an antioxidant and a stimulator of hepatocyte growth factor (HGF) production. Previously, we reported that depletion of growth factors such as fibroblast growth factor (FGF)-2, epidermal growth factor (EGF), FGF-4 and HGF during serial passage could induce autophagy, senescence and down-regulation of stemness (proliferation via FGF-2/-4 and differentiation via HGF). In this study, we investigated the proliferation and differentiation potential of BMSCs by FGF-2 and Asc-2P. Co-treatment with FGF-2 and Asc-2P induced optimal proliferation of BMSCs and increased the accumulation rate of BMSC numbers during a 2-month culture period. Moreover, differentiation potential was maintained by co-treatment with FGF-2 and Asc-2P via HGF expression. Adipogenic differentiation potential by FGF-2 and Asc-2P was dramatically suppressed by c-Met inhibitors (SU11274). These data suggest that co-treatment with FGF-2 and Asc-2P would be beneficial in obtaining BMSCs that possess "stemness" during long-term culture.

Early to Phase II drugs currently under investigation for the treatment of liver fibrosis

INTRODUCTION

Chronic liver diseases represent a high unmet medical need and are characterized by persistent inflammation, parenchymal damage and fibrotic remodeling, leading eventually to cirrhosis and hepatic failure. Besides the persisting high prevalence of chronic viral hepatitis B and C, the dramatic increase in nonalcoholic steatohepatitis is now considered to be a major pathophysiologic driver for fibrosis development and subsequently cirrhosis. Increasing evidence suggests that also liver cirrhosis can regress when treated adequately.

AREAS COVERED

Herein, the authors review the underlying pathophysiologic mechanisms leading to fibrotic remodeling in the liver. They also highlight the options for novel treatment strategies by using molecular targeted agents.

EXPERT OPINION

New in vitro and preclinical animal models, and the careful selection of patients with high disease dynamics for clinical studies, provide a sound basis for the clinical development of antifibrotic agents in humans. Surrogate parameters of liver function, inflammation, tissue remodeling and damage, as well as noninvasive imaging techniques, can be applied in clinical trials to provide fast readouts and novel and reliable endpoints for trial design, and provide an attractive regulatory environment for this emerging disease area.

Alcoholic liver disease: Treatment

The excess consumption of alcohol is associated with alcoholic liver diseases (ALD). ALD is a major healthcare problem, personal and social burden, and significant reason for economic loss worldwide. The ALD spectrum includes alcoholic fatty liver, alcoholic hepatitis, cirrhosis, and the development of hepatocellular carcinoma. The diagnosis of ALD is based on a combination of clinical features, including a history of significant alcohol intake, evidence of liver disease, and laboratory findings. Abstinence is the most important treatment for ALD and the treatment plan varies according to the stage of the disease. Various treatments including abstinence, nutritional therapy, pharmacological therapy, psychotherapy, and surgery are currently available. For severe alcoholic hepatitis, corticosteroid or pentoxifylline are recommended based on the guidelines. In addition, new therapeutic targets are being under investigation.

Bone marrow derived stem cells for the treatment of end-stage liver disease

End-stage disease due to liver cirrhosis is an important cause of death worldwide. Cirrhosis results from progressive, extensive fibrosis and impaired hepatocyte regeneration. The only curative treatment is liver transplantation, but due to the several limitations of this procedure, the interest in alternative therapeutic strategies is increasing. In particular, the potential of bone marrow stem cell (BMSC) therapy in cirrhosis has been explored in different trials. In this article, we evaluate the results of 18 prospective clinical trials, and we provide a descriptive overview of recent advances in the research on hepatic regenerative medicine. The main message from the currently available data in the literature is that BMSC therapy is extremely promising in the context of liver cirrhosis. However, its application should be further explored in randomized, controlled trials with large cohorts and long follow-ups.

Pathophysiology of portal hypertension

Portal hypertension is a major complication of liver disease that results from a variety of pathologic conditions that increase the resistance to the portal blood flow into the liver. As portal hypertension develops, the formation of collateral vessels and arterial vasodilation progresses, which results in increased blood flow to the portal circulation. Hyperdynamic circulatory syndrome develops, leading to esophageal varices or ascites. This article summarizes the factors that increase (1) intrahepatic vascular resistance and (2) the blood flow in the splanchnic and systemic circulations in liver cirrhosis. In addition, the future directions of basic/clinical research in portal hypertension are discussed.

The role of growth factors in maintenance of stemness in bone marrow-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) are an active topic of research in regenerative medicine due to their ability to secrete a variety of growth factors and cytokines that promote healing of damaged tissues and organs. In addition, these secreted growth factors and cytokines have been shown to exert an autocrine effect by regulating MSC proliferation and differentiation. We found that expression of EGF, FGF-4 and HGF were down-regulated during serial passage of bone marrow-derived mesenchymal stem cells (BMSCs). Proliferation and differentiation potentials of BMSCs treated with these growth factors for 2 months were evaluated and compared to BMSCs treated with FGF-2, which increased proliferation of BMSCs. FGF-2 and -4 increased proliferation potentials at high levels, about 76- and 26-fold, respectively, for 2 months, while EGF and HGF increased proliferation of BMSCs by less than 2.8-fold. Interestingly, differentiation potential, especially adipogenesis, was maintained only by HGF treatment. Treatment with FGF-2 rapidly induced activation of AKT and later induced ERK activation. The basal level of phosphorylated ERK increased during serial passage of BMSCs treated with FGF-2. The expression of LC3-II, an autophagy marker, was gradually increased and the population of senescent cells was increased dramatically at passage 7 in non-treated controls. But FGF-2 and FGF-4 suppressed LC3-II expression and down-regulated senescent cells during long-term (i.e. 2month) cultures. Taken together, depletion of growth factors during serial passage could induce autophagy, senescence and down-regulation of stemness (proliferation via FGF-2/-4 and differentiation via HGF) through suppression of AKT and ERK signaling.