Enhanced hepatic differentiation of mesenchymal stem cells after pretreatment with injured liver tissue. Differentiation. 2011;81:42-48. [PMID: 20943307 DOI: 10.1016/j.diff.2010.08.005]

Comparative Histological Study of Therapeutic Effect of Mesenchymal Stem Cells versus Mesenchymal Stem Cells Co-Cultured with Liver Tissue on Carbon Tetrachloride-Induced Hepatotoxicity in Adult Male Albino Rats

Context

Liver diseases are major causes of morbidity and mortality. Mesenchymal stem cells (MSCs) have immunomodulatory, anti-inflammatory, and antifibrotic effects, so they can be used in the treatment of liver diseases. MSCs co-cultured with diseased liver tissue improve the homing capacity, survival rate, and paracrine effects of the MSCs, as well as the ability to enhance liver function.

Aims

This work aimed to study the therapeutic effect of MSCs versus MSCs co-cultured with liver tissue on carbon tetrachloride (CCl4)-induced hepatotoxicity in adult male albino rats.

Settings and Design

Twenty adult male albino rats were divided into four equal groups; Group I (control group), Group II received CCl4 intraperitoneally (i.p.), Group III received CCl4 i.p. and then injected with MSCs intravenously (i.v.), and Group IV received CCl4 i.p. and then injected with co-cultured MSCs i.v.

Materials and Methods

Finally, liver specimens were processed for light microscopy (LM) and electron microscopy (EM). Statistical analysis was carried out to assess histological scoring, area percentage of collagen fibers, number of glial fibrillary acidic protein-positive cells, and biochemical analysis of alanine aminotransferase and aspartate aminotransferase.

Statistical Analysis Used

Statistical analysis of (histological scoring, area % of collagen fibers, and biochemical analysis) was done by using one-way analysis of variance (ANOVA) test using graphpad software (SanDiego, CA, USA). The means ± standard deviations were used for statistical analysis.

Results

LM of Group II revealed loss of hepatic architecture and diffuse fibrosis with dilated congested blood vessels, bile ductular proliferation, and cellular infiltrations. Vacuolated cytoplasm with or without pyknotic nuclei was observed in addition to micro- and macro-steatosis. EM demonstrated disfigured hepatocytes with abnormal organelles surrounding atypical nucleus. Group III showed restoration of the normal liver architecture with greater extent in Group IV. Statistical analysis confirmed the microscopic findings.

Conclusions

Co-cultured MSCs with diseased liver tissue augmented the therapeutic effects of MSCs in treating hepatotoxicity induced by CCl4 in adult male albino rats.

Combinatorial Therapeutic Potential of Stem Cells and Benzimidazol Derivatives for the Reduction of Liver Fibrosis

(1) Background: Liver fibrosis is currently one of the top ten causes of death worldwide. Stem cells transplantation using mesenchymal stem cells (MSCs) is an alternative therapy which is used in the place of organ transplant, due to the incapacity of stem cells to endure oxidative stress in the damage site, thus affecting the healing process. The present study aimed to enhance the therapeutic potential of MSCs using combined therapy, along with the novel synthetic compounds of benzimidazol derivatives. (2) Methods: Eighteen compound series (benzimidazol derivatives) were screened against liver fibrosis using an in vitro CCl4-induced injury model on cultured hepatocytes. IC50 values were calculated on the bases of LDH assay and cell viability assay. (3) Results: Among the eighteen compounds, compounds (10), (14) and (18) were selected on the basis of IC50 value, and compound (10) was the most potent and had the lowest IC50 value in the LDH assay (8.399 ± 0.23 uM) and cell viability assay (4.73 ± 0.37 uM). Next, these compounds were combined with MSCs using an in vitro hepatocytes injury culture and in vivo rat fibrotic model. The effect of the MSCs + compounds treatment on injured hepatocytes was evaluated using LDH assay, cell viability assay, GSH assay and real-time PCR analysis and immuno-staining for caspase-3. Significant reductions in LDH level, caspase-3 and apoptotic marker genes were noted in MSCs + compounds-treated injured hepatocytes. In vivo data also showed the increased homing of the MSCs, along with compounds after transplantation. Real-time PCR analysis and TUNEL assay results also support our study. (4) Conclusions: It was concluded that compounds (10), (14) and (18) can be used in combination with MSCs to reduce liver fibrosis.

Advance of Mesenchymal Stem Cells in Chronic End-Stage Liver Disease Control

The chronic liver diseases will slowly develop into liver fibrosis, cirrhosis, and even liver cancer if no proper control is performed with high efficiency. Up to now, the most effective treatment for end-stage liver diseases is liver transplantation. However, liver transplantation has the problems of donor deficiency, low matching rate, surgical complications, high cost, and immune rejection. These problems indicate that novel therapeutic strategies are urgently required. Mesenchymal stem cells (MSCs) are somatic stem cells with multidirectional differentiation potential and self-renewal ability. MSCs can secrete a large number of cytokines, chemokines, immunomodulatory molecules, and hepatotrophic factors, as well as produce extracellular vesicles. They alleviate liver diseases by differentiating to hepatocyte-like cells, immunomodulation, homing to the injured site, regulating cell ferroptosis, regulating cell autophagy, paracrine effects, and MSC-mitochondrial transfer. In this review, we focus on the main resources of MSCs, underlying therapeutic mechanisms, clinical applications, and efforts made to improve MSC-based cell therapy efficiency.

Mesenchymal stromal cells (MSCs) and their exosome in acute liver failure (ALF): a comprehensive review

Recently, mesenchymal stromal cells (MSCs) and their derivative exosome have become a promising approach in the context of liver diseases therapy, in particular, acute liver failure (ALF). In addition to their differentiation into hepatocytes in vivo, which is partially involved in liver regeneration, MSCs support liver regeneration as a result of their appreciated competencies, such as antiapoptotic, immunomodulatory, antifibrotic, and also antioxidant attributes. Further, MSCs-secreted molecules inspire hepatocyte proliferation in vivo, facilitating damaged tissue recovery in ALF. Given these properties, various MSCs-based approaches have evolved and resulted in encouraging outcomes in ALF animal models and also displayed safety and also modest efficacy in human studies, providing a new avenue for ALF therapy. Irrespective of MSCs-derived exosome, MSCs-based strategies in ALF include administration of native MSCs, genetically modified MSCs, pretreated MSCs, MSCs delivery using biomaterials, and also MSCs in combination with and other therapeutic molecules or modalities. Herein, we will deliver an overview regarding the therapeutic effects of the MSCs and their exosomes in ALF. As well, we will discuss recent progress in preclinical and clinical studies and current challenges in MSCs-based therapies in ALF, with a special focus on in vivo reports.

The Application of Mesenchymal Stem Cells in the Treatment of Liver Diseases: Mechanism, Efficacy, and Safety Issues

Mesenchymal stem cell (MSC) transplantation is a novel treatment for liver diseases due to the roles of MSCs in regeneration, fibrosis inhibition and immune regulation. However, the mechanisms are still not completely understood. Despite the significant efficacy of MSC therapy in animal models and preliminary clinical trials, issues remain. The efficacy and safety of MSC-based therapy in the treatment of liver diseases remains a challenging issue that requires more investigation. This article reviews recent studies on the mechanisms of MSCs in liver diseases and the associated challenges and suggests potential future applications.

Adipose-tissue derived porcine mesenchymal stem cells efficiently ameliorate CCl4-induced acute liver failure in mice

Adipose tissue derived mesenchymal stem cells (ADMSCs) may be an attractive therapeutic source for acute liver injury because of their high accessibility and non-invasiveness. Here, we investigated the therapeutic potentials of porcine ADMSCs for acute liver failure (ALF). The morphology, differentiation potential, expression patterns of cell surface markers and liver-specific genes were compared between the ADMSCs derived from the pigs with or without ALF. For therapeutic studies, the expanded porcine ADMSCs from either ALF pig (ALF-ADMSCs) or healthy control pig (Nor-ADMSCs) of passage 3 were transplanted into CCl4-induced ALF mice, and the liver histology and functional tests were performed at days 1, 7, 14, and 21 after cell transplantation. ALF-ADMSCs expressed higher mRNA level of hepatic growth factor (HGF) than the Nor-ADMSCs. Both ALF-ADMSCs and Nor-ADMSCs improved liver histology, functions, and mouse survival rate. Higher level of porcine hepatocyte-specific genes was seen in the livers of ALF-ADMSCs transplanted mice as compared to the Nor-ADMSCs transplanted mice. In particular, ALF-ADMSCs transplanted mice expressed significantly higher level of albumin and cytokeratin 18 in the liver tissues as compared to the Nor-ADMSCs transplanted mice. ALF-ADMSCs might be superior to Nor-ADMSCs in the treatment of ALF as the former possesses stronger hepatic differentiation potential.

Pre-treatments enhance the therapeutic effects of mesenchymal stem cells in liver diseases

Liver diseases caused by viral infection, alcohol abuse and metabolic disorders can progress to end‐stage liver failure, liver cirrhosis and liver cancer, which are a growing cause of death worldwide. Although liver transplantation and hepatocyte transplantation are useful strategies to promote liver regeneration, they are limited by scarce sources of organs and hepatocytes. Mesenchymal stem cells (MSCs) restore liver injury after hepatogenic differentiation and exert immunomodulatory, anti‐inflammatory, antifibrotic, antioxidative stress and antiapoptotic effects on liver cells in vivo. After isolation and culture in vitro, MSCs are faced with nutrient and oxygen deprivation, and external growth factors maintain MSC capacities for further applications. In addition, MSCs are placed in a harsh microenvironment, and anoikis and inflammation after transplantation in vivo significantly decrease their regenerative capacity. Pre‐treatment with chemical agents, hypoxia, an inflammatory microenvironment and gene modification can protect MSCs against injury, and pre‐treated MSCs show improved hepatogenic differentiation, homing capacity, survival and paracrine effects in vitro and in vivo in regard to attenuating liver injury. In this review, we mainly focus on pre‐treatments and the underlying mechanisms for improving the therapeutic effects of MSCs in various liver diseases. Thus, we provide evidence for the development of MSC‐based cell therapy to prevent acute or chronic liver injury. Mesenchymal stem cells have potential as a therapeutic to prolong the survival of patients with end‐stage liver diseases in the near future.

Decellularized liver bioscaffold: a histological and immunohistochemical comparison between normal, fibrotic and hepatocellular carcinoma

Aim of the study

Increasing demand for liver transplantation represents an important health burden. Decellularized liver bioscaffold can be a suitable alternative for whole organ transplantation. However, various pathologies can affect the structure of decellularized scaffolds.This work discusses differences between hepatic fibrosis (HF), hepatocellular carcinoma (HCC) and normal decellularized liver bioscaffolds.

Material and methods

Murine models of HF and HCC were created, livers from normal, HF and HCC were decellularized, and evaluation of decellularization was done using morphological, histological and DNA analysis examination. Also, immunohistochemical staining using collagen, laminin, fibronectin and alphafetoprotein was done. Deposition area and intensity of the used immunohistochemical staining in liver capsules and the staining deposition thickness in the blood vessels and hepatic capsule walls were measured for comparison between the three models.

Results

Normal, HF and HCC livers were decellularized efficiently as confirmed by histological and DNA estimation. HCC decellularized samples showed significantly higher collagen, fibronectin and laminin deposition in both capsule and blood vessels, followed by HF decellularized samples, which also showed the highest thickness of laminin deposition in both capsule and blood vessels, then the normal model, which recorded the lowest value. Alphafetoprotein positive cells were absent in normal and HF, with rare cells in HCC.

Conclusions

Even pathologic livers, HF and HCC, can be efficiently decellularized, showing normal morphology and architecture. However, HCC and HF showed significantly higher deposition of extracellular matrix proteins: collagen, fibronectin and laminin. The impact of these differences on physiological and immunological functions of the bioscaffold requires recellularization experiments.

Mesenchymal stem cell transplantation improves chronic colitis-associated complications through inhibiting the activity of toll-like receptor-4 in mice

BACKGROUND

A variety of extra-intestinal manifestations (EIMs), including hepatobiliary complications, are associated with inflammatory bowel disease (IBD). Mesenchymal stem cells (MSCs) have been shown to play a potential role in the therapy of IBD. This study was designed to investigate the effect and mechanism of MSCs on chronic colitis-associated hepatobiliary complications using mouse chronic colitis models induced by dextran sulfate sodium (DSS).

METHODS

DSS-induced mouse chronic colitis models were established and treated with MSCs. Severity of colitis was evaluated by disease activity index (DAI), body weight (BW), colon length and histopathology. Serum lipopolysaccharide (LPS) levels were detected by limulus amebocyte lysate test (LAL-test). Histology and liver function of the mice were checked correspondingly. Serum LPS levels and bacterial translocation of mesenteric lymph nodes (MLN) were detected. Pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), interleukin-17A (IL-17A), Toll receptor 4 (TLR4), TNF receptor-associated factor 6 (TRAF6) and nuclear factor kappa B (NF-κB) were detected by immunohistochemical staining, western blot analysis and real-time PCR, respectively.

RESULTS

The DSS-induced chronic colitis model was characterized by reduced BW, high DAI, worsened histologic inflammation, and high levels of LPS and E. coli. Liver histopathological lesions, impaired liver function, enhanced proteins and mRNA levels of TNF-α, IFN-γ, IL-1β, IL-17A, TLR4, TRAF6 and NF-κB were observed after DSS administration. MSCs transplantation markedly ameliorated the pathology of colon and liver by reduction of LPS levels and proteins and mRNA expressions of TNF-α, IFN-γ, IL-1β, IL-17A, TLR4, TRAF6 and NF-κB.

CONCLUSIONS

MSCs can improve chronic colitis-associated hepatobiliary complications, probably by inhibition of enterogenous endotoxemia and hepatic inflammation through LPS/TLR4 pathway. MSCs may represent a novel therapeutic approach for chronic colitis-associated hepatobiliary complications.

Therapeutic potential effect of bone marrow-derived mesenchymal stem cells on chronic liver disease in murine Schistosomiasis Mansoni

Some reports have shown that mesenchymal stem cells (MSCs) therapy could ameliorate chemically-induced hepatic fibrosis. This research assesses the therapeutic action of bone marrow mesenchymal stem cells (BM-MSCs) on chronic diseased liver in Schistosoma mansoni infected mice. All infected female mice divided into three groups, one group (15 mice) treated with oral praziquantel (PZQ), second group (15 mice) received intravenous injection of BM-MSCs and third group (15 mice) treated with both MSCs + PZQ. Two control groups (15 mice each) subdivided into one infected and second healthy one. BM-MSCs were obtained from bones of both femur and tibia of male mice (30 mice), then cultured and characterized morphologically by detection of CD105 by flow cytometer. Liver tissues for all groups were examined histopathologically. Measuring of the collagen 1 gene expression was done by real-time PCR and immunohistochemical study to detect stem cells differentiation for detection of MSCs engraftments in liver tissue. MSCs treatment caused marked improvement and regression of fibrosis, and prevents deposition of collagen and reduced the expression of collagen 1 gene in infected mice on their liver tissues, especially when used with PZQ in mice treatment. It can be concluded that, MSCs is a good therapeutic method for liver fibrosis caused by S. mansoni infection.

Historical Perspectives and Advances in Mesenchymal Stem Cell Research for the Treatment of Liver Diseases

Liver transplantation is the only effective therapy for patients with decompensated cirrhosis and fulminant liver failure. However, due to a shortage of donor livers and complications associated with immune suppression, there is an urgent need for new therapeutic strategies for patients with end-stage liver diseases. Given their unique function in self-renewal and differentiation potential, stem cells might be used to regenerate damaged liver tissue. Recent studies have shown that stem cell-based therapies can improve liver function in a mouse model of hepatic failure. Moreover, acellular liver scaffolds seeded with hepatocytes produced functional bioengineered livers for organ transplantation in preclinical studies. The therapeutic potential of stem cells or their differentiated progenies will depend on their capacity to differentiate into mature and functional cell types after transplantation. It will also be important to devise methods to overcome their genomic instability, immune reactivity, and tumorigenic potential. We review directions and advances in the use of mesenchymal stem cells and their derived hepatocytes for liver regeneration. We also discuss the potential applications of hepatocytes derived from human pluripotent stem cells and challenges to using these cells in treating end-stage liver disease.

Stem Cell and Advanced Nano Bioceramic Interactions

Bioceramics are type of biomaterials generally used for orthopaedic applications due to their similar structure with bone. Especially regarding to their osteoinductivity and osteoconductivity, they are used as biodegradable scaffolds for bone regeneration along with mesenchymal stem cells. Since chemical properties of bioceramics are important for regeneration of tissue, physical properties are also important for cell proliferation. In this respect, several different manufacturing methods are used for manufacturing nano scale bioceramics. These nano scale bioceramics are used for regeneration of bone and cartilage both alone or with other types of biomaterials. They can also act as carrier for the delivery of drugs in musculoskeletal infections without causing any systemic toxicity.

Serum from CCl4-induced acute rat injury model induces differentiation of ADSCs towards hepatic cells and reduces liver fibrosis

Cellular therapies hold promise to alleviate liver diseases. This study explored the potential of allogenic serum isolated from rat with acute CCl₄ injury to differentiate adipose derived stem cells (ADSCs) towards hepatic lineage. Acute liver injury was induced by CCl₄ which caused significant increase in serum levels of VEGF, SDF1α and EGF. ADSCs were preconditioned with 3% serum isolated from normal and acute liver injury models. ADSCs showed enhanced expression of hepatic markers (AFP, albumin, CK8 and CK19). These differentiated ADSCs were transplanted intra-hepatically in CCl₄-induced liver fibrosis model. After one month of transplantation, fibrosis and liver functions (alkaline phosphatase, ALAT and bilirubin) showed marked improvement in acute injury group. Elevated expression of hepatic (AFP, albumin, CK 18 and HNF4a) and pro survival markers (PCNA and VEGF) and improvement in liver architecture as deduced from results of alpha smooth muscle actin, Sirius red and Masson's trichome staining was observed.

Current status and future prospects of mesenchymal stem cell therapy for liver fibrosis

Liver fibrosis is the end-stage of many chronic liver diseases and is a significant health threat. The only effective therapy is liver transplantation, which still has many problems, including the lack of donor sources, immunological rejection, and high surgery costs, among others. However, the use of cell therapy is becoming more prevalent, and mesenchymal stem cells (MSCs) seem to be a promising cell type for the treatment of liver fibrosis. MSCs have multiple differentiation abilities, allowing them to migrate directly into injured tissue and differentiate into hepatocyte-like cells. Additionally, MSCs can release various growth factors and cytokines to increase hepatocyte regeneration, regress liver fibrosis, and regulate inflammation and immune responses. In this review, we summarize the current uses of MSC therapies for liver fibrosis and suggest potential future applications.

Mesenchymal Stem Cells Transplantation following Partial Hepatectomy: A New Concept to Promote Liver Regeneration-Systematic Review of the Literature Focused on Experimental Studies in Rodent Models

Mesenchymal stem cells (MSCs) are an attractive source for regenerative medicine because they are easily accessible through minimally invasive methods and have the potential to enhance liver regeneration (LG) and improve liver function, following partial hepatectomy (PH) and acute or chronic liver injury. A systematic review of the literature was conducted for articles published up to September 1st, 2016, using the MEDLINE database. The keywords that were used in various combinations were as follows: “Mesenchymal stem cells”, “transplantation”, “stem cells”, “adipose tissue derived stem cells”, “bone marrow-derived stem cells”, “partial hepatectomy”, “acute liver failure”, “chronic liver failure”, “liver fibrosis”, “liver cirrhosis”, “rats”, “mice”, and “liver regeneration”. All introduced keywords were searched for separately in MeSH Database to control relevance and terminological accuracy and validity. A total of 41 articles were identified for potential inclusion and reviewed in detail. After a strict selection process, a total of 28 articles were excluded, leaving 13 articles to form the basis of this systematic review. MSCs transplantation promoted LG and improved liver function. Furthermore, MSCs had the ability to differentiate in hepatocyte-like cells, increase survival, and protect hepatocytes by paracrine mechanisms. MSCs transplantation may provide beneficial effects in the process of LG after PH and acute or chronic liver injury. They may represent a new therapeutic option to treat posthepatectomy acute liver failure.

In vitro differentiated hepatic oval-like cells enhance hepatic regeneration in CCl4 -induced hepatic injury

Hepatic oval cells are likely to be activated during advanced stage of liver fibrosis to reconstruct damaged hepatic tissue. However, their scarcity, difficulties in isolation, and in vitro expansion hampered their transplantation in fibrotic liver. This study was aimed to investigate the repair potential of in vitro differentiated hepatic oval-like cells in CCl₄ -induced liver fibrosis. BMSCs and oval cells were isolated and characterized from C57BL/6 GFP⁺ mice. BMSCs were differentiated into oval cells by preconditioning with HGF, EGF, SCF, and LIF and analyzed for the oval cells-specific genes. Efficiency of oval cells to reduce hepatocyte injury was studied by determining cell viability, release of LDH, and biochemical tests in a co-culture system. Further, in vivo repair potential of differentiated oval cells was determined in CCl₄ -induced fibrotic model by gene expression analysis, biochemical tests, mason trichrome, and Sirius red staining. Differentiated oval cells expressed hepatic oval cells-specific markers AFP, ALB, CK8, CK18, CK19. These differentiated cells when co-cultured with injured hepatocytes showed significant hepato-protection as measured by reduction in apoptosis, LDH release, and improvement in liver functions. Transplantation of differentiated oval cells like cells in fibrotic livers exhibited enhanced homing, reduced liver fibrosis, and improved liver functions by augmenting hepatic microenvironment by improved liver functions. This preconditioning strategy to differentiate BMSCs into oval cell leads to improved survival and homing of transplanted cells. In addition, reduction in fibrosis and functional improvement in mice with CCl₄ -induced liver fibrosis was achieved.

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.

Muse Cells, Nontumorigenic Pluripotent-Like Stem Cells, Have Liver Regeneration Capacity Through Specific Homing and Cell Replacement in a Mouse Model of Liver Fibrosis

Muse cells, a novel type of nontumorigenic pluripotent-like stem cells, reside in the bone marrow, skin, and adipose tissue and are collectable as cells positive for pluripotent surface marker SSEA-3. They are able to differentiate into cells representative of all three germ layers. The capacity of intravenously injected human bone marrow-derived Muse cells to repair an immunodeficient mouse model of liver fibrosis was evaluated in this study. The cells exhibited the ability to spontaneously differentiate into hepatoblast/hepatocyte lineage cells in vitro. They demonstrated a high migration capacity toward the serum and liver section of carbon tetrachloride-treated mice in vitro. In vivo, they specifically accumulated in the liver, but not in other organs except, to a lesser extent, in the lungs at 2 weeks after intravenous injection in the liver fibrosis model. After homing, Muse cells spontaneously differentiated in vivo into HepPar-1 (71.1 ± 15.2%), human albumin (54.3 ± 8.2%), and anti-trypsin (47.9 ± 4.6%)-positive cells without fusing with host hepatocytes, and expressed mature functional markers such as human CYP1A2 and human Glc-6-Pase at 8 weeks after injection. Recovery in serum, total bilirubin, and albumin and significant attenuation of fibrosis were recognized with statistical differences between the Muse cell-transplanted group and the control groups, which received the vehicle or the same number of a non-Muse cell population of MSCs (MSCs in which Muse cells were eliminated). Thus, unlike ESCs and iPSCs, Muse cells are unique in their efficient migration and integration into the damaged liver after intravenous injection, nontumorigenicity, and spontaneous differentiation into hepatocytes, rendering induction into hepatocytes prior to transplantation unnecessary. They may repair liver fibrosis by two simple steps: expansion after collection from the bone marrow and intravenous injection. A therapeutic strategy such as this is feasible and may provide significant advancements toward liver regeneration in patients with liver disease.

3D Spheroid Culture Enhances the Expression of Antifibrotic Factors in Human Adipose-Derived MSCs and Improves Their Therapeutic Effects on Hepatic Fibrosis

Three-dimensional (3D) cell culture has been reported to increase the therapeutic potentials of mesenchymal stem cells (MSCs). However, the action mechanisms of 3D MSCs vary greatly and are far from being thoroughly investigated. In this study, we aimed to investigate the therapeutic effects of 3D spheroids of human adipose-derived MSCs for hepatic fibrosis. Our results showed that 3D culture enhanced the expression of antifibrotic factors by MSCs, including insulin growth factor 1 (IGF-1), interleukin-6 (IL-6), and hepatocyte growth factor (HGF). In vitro studies indicated conditioned medium of 3D cultured MSCs protected hepatocytes from cell injury and apoptosis more effectively compared with 2D cultured cells. More importantly, when transplanted into model mice with hepatic fibrosis, 3D spheroids of MSCs were more beneficial in ameliorating hepatic fibrosis and improving liver function than 2D cultured cells. Therefore, the 3D culture strategy improved the therapeutic effects of MSCs and might be promising for treatment of hepatic fibrosis.

Cross effects of resveratrol and mesenchymal stem cells on liver regeneration and homing in partially hepatectomized rats

In this study, we examined the effect of preoperatively administered resveratrol (RV) and mesenchymal stem cells (MSCs) on regeneration of partially hepatectomized rat liver. We also evaluated the effect of RV on homing of MSCs. MSCs were isolated from bone marrow and cultured in vitro. Wistar albino rats were randomly divided into four groups. In groups, rats received (1) no treatment, (2) single dose RV, (3) MSCs and (4) RV plus MSCs before partial hepatectomy (PH). Injected MSCs were traced by labeling them with green fluorescent protein, and liver regeneration was determined by comparison of liver weight gain, histological examination and immunohistochemical staining with proliferating cell nuclear antigen (PCNA) for mitotic cells. The expression levels of tumor necrosis factor -alpha (TNF-α), interleukin-6 (IL-6) and hepatocyte growth factor (HGF) were also determined in the parafin sections of liver specimens with immunohistochemical staining. Administration of RV and MSCs separately or together enhanced liver regeneration despite decreasing the TNF-α and IL-6 expression. This positive contribution was probably due to direct raising effect on HGF for RV and HGF expression for MSCs that we demonstrated with immunohistochemical staining. Additionally, RV increased the homing of MSCs in liver probably related to life prolonging effect on MSCs. These results indicate that preoperative RV as well as MSCs application enhances liver regeneration after partial hepatectomy in rats. Paying attention to RV about the effect on liver regeneration and homing of MSCs might be the goal of further investigations.

Porcine Adipose-Derived Mesenchymal Stem Cells Retain Their Stem Cell Characteristics and Cell Activities While Enhancing the Expression of Liver-Specific Genes after Acute Liver Failure

Acute liver failure (ALF) is a kind of complicated syndrome. Furthermore, adipose-derived mesenchymal stem cells (ADMSCs) can serve as a useful cell resource for autotransplantation due to their abundance and micro-invasive accessability. However, it is unknown how ALF will influence the characteristics of ADMSCs and whether ADMSCs from patients suffering from end-stage liver diseases are potential candidates for autotransplantation. This study was designed to compare various properties of ALF-derived ADMSCs with normal ADMSCs in pig models, with regard to their cellular morphology, cell proliferative ability, cell apoptosis, expression of surface antigens, mitochondrial and lysosomal activities, multilineage potency, and expression of liver-specific genes. Our results showed that ALF does not influence the stem cell characteristics and cell activities of ADMSCs. Intriguingly, the expression levels of several liver-specific genes in ALF-derived ADMSCs are higher than in normal ADMSCs. In conclusion, our findings indicate that the stem cell characteristics and cell activities of ADMSCs were not altered by ALF and these cells can serve as a new source for regenerative medicine.

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.

In vitro culture of isolated primary hepatocytes and stem cell-derived hepatocyte-like cells for liver regeneration

Various liver diseases result in terminal hepatic failure, and liver transplantation, cell transplantation and artificial liver support systems are emerging as effective therapies for severe hepatic disease. However, all of these treatments are limited by organ or cell resources, so developing a sufficient number of functional hepatocytes for liver regeneration is a priority. Liver regeneration is a complex process regulated by growth factors (GFs), cytokines, transcription factors (TFs), hormones, oxidative stress products, metabolic networks, and microRNA. It is well-known that the function of isolated primary hepatocytes is hard to maintain; when cultured in vitro, these cells readily undergo dedifferentiation, causing them to lose hepatocyte function. For this reason, most studies focus on inducing stem cells, such as embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), hepatic progenitor cells (HPCs), and mesenchymal stem cells (MSCs), to differentiate into hepatocyte-like cells (HLCs) in vitro. In this review, we mainly focus on the nature of the liver regeneration process and discuss how to maintain and enhance in vitro hepatic function of isolated primary hepatocytes or stem cell-derived HLCs for liver regeneration. In this way, hepatocytes or HLCs may be applied for clinical use for the treatment of terminal liver diseases and may prolong the survival time of patients in the near future.

Microencapsulated human mesenchymal stem cells decrease liver fibrosis in mice

BACKGROUND & AIMS

Mesenchymal stem cell (MSC) transplantation was shown to be effective for the treatment of liver fibrosis, but the mechanisms of action are not yet fully understood. We transplanted encapsulated human MSCs in two mouse models of liver fibrosis to determine the mechanisms behind the protective effect.

METHODS

Human bone marrow-derived MSCs were microencapsulated in novel alginate-polyethylene glycol microspheres. In vitro, we analyzed the effect of MSC-conditioned medium on the activation of hepatic stellate cells and the viability, proliferation, cytokine secretion, and differentiation capacity of encapsulated MSCs. The level of fibrosis induced by bile duct ligation (BDL) or carbon tetrachloride (CCl4) was assessed after intraperitoneal transplantation of encapsulated MSCs, encapsulated human fibroblasts, and empty microspheres.

RESULTS

MSC-conditioned medium inhibited hepatic stellate cell activation and release of MSC secreted anti-apoptotic (IL-6, IGFBP-2) and anti-inflammatory (IL-1Ra) cytokines. Viability, proliferation, and cytokine secretion of microencapsulated MSCs were similar to those of non-encapsulated MSCs. Within the microspheres, MSCs maintained their capacity to differentiate into adipocytes, chondrocytes, and osteocytes. 23% (5/22) of the MSC clones were able to produce anti-inflammatory IL-1Ra in vitro. Microencapsulated MSCs significantly delayed the development of BDL- and CCl4-induced liver fibrosis. Fibroblasts had an intermediate effect against CCl4-induced fibrosis. Mice transplanted with encapsulated MSCs showed lower mRNA levels of collagen type I, whereas levels of matrix metalloproteinase 9 were significantly higher. Human IL-1Ra was detected in the serum of 36% (4/11) of the mice transplanted with microencapsulated MSCs.

CONCLUSIONS

MSC-derived soluble molecules are responsible for an anti-fibrotic effect in experimental liver fibrosis.

The multiple functional roles of mesenchymal stem cells in participating in treating liver diseases

Mesenchymal stem cells (MSCs) are a group of stem cells derived from the mesodermal mesenchyme. MSCs can be obtained from a variety of tissues, including bone marrow, umbilical cord tissue, umbilical cord blood, peripheral blood and adipose tissue. Under certain conditions, MSCs can differentiate into many cell types both in vitro and in vivo, including hepatocytes. To date, four main strategies have been developed to induce the transdifferentiation of MSCs into hepatocytes: addition of chemical compounds and cytokines, genetic modification, adjustment of the micro-environment and alteration of the physical parameters used for culturing MSCs. Although the phenomenon of transdifferentiation of MSCs into hepatocytes has been described, the detailed mechanism is far from clear. Generally, the mechanism is a cascade reaction whereby stimulating factors activate cellular signalling pathways, which in turn promote the production of transcription factors, leading to hepatic gene expression. Because MSCs can give rise to hepatocytes, they are promising to be used as a new treatment for liver dysfunction or as a bridge to liver transplantation. Numerous studies have confirmed the therapeutic effects of MSCs on hepatic fibrosis, cirrhosis and other liver diseases, which may be related to the differentiation of MSCs into functional hepatocytes. In addition to transdifferentiation into hepatocytes, when MSCs are used to treat liver disease, they may also inhibit hepatocellular apoptosis and secrete various bioactive molecules to promote liver regeneration. In this review, the capacity and molecular mechanism of MSC transdifferentiation, and the therapeutic effects of MSCs on liver diseases are thoroughly discussed.

A proposed novel stem cell therapy protocol for liver cirrhosis

Currently, there is not an effective therapy for cirrhosis of the liver except for liver transplant. However, finding a compatible liver is difficult due to the low supply and increased demand for healthy livers. Stem cell therapy may be a solution for liver cirrhosis. In our previous report, stem cells from Wharton's jelly and bone marrow were shown to improve liver function in a chemically induced liver fibrosis animal model. However, the immunological rejection of an allograft is always a risk for clinical application. In this study proposal, we suggest using human adipose-derived stem cells (ADSCs) because they are an immune-privileged cell type; they lack human leukocyte antigen-DR expression, and they also suppress the proliferation of activated allogenic lymphocytes and inhibit the production of inflammatory cytokines. In addition, ADSCs contain a sufficient amount of adult stem cells for autologous transplantation. Based on these benefits, ADSCs are promising candidates for clinical application when compared to other stem cell types. The aim of our study will be to investigate the safety and efficacy of autologous ADSCs for the clinical treatment of liver cirrhosis.

Mesenchymal Stem Cells Pretreated with HGF and FGF4 Can Reduce Liver Fibrosis in Mice

Stem cells have opened a new avenue to treat liver fibrosis. We investigated in vitro and in vivo the effect of cytokine (HGF and FGF4) pretreated MSCs in reduction of CCl4 liver injury. Mouse MSCs were pretreated with cytokines to improve their ability to reduce CCl4 injury. In vitro we gave CCl4 injury to mouse hepatocytes and cocultured it with untreated and cytokines pretreated MSCs. For in vivo study we labeled MSCs with PKH-26 and transplanted them into CCl4 injured mice by direct injection into liver. In vitro data showed that cytokines pretreated MSCs significantly reduce LDH level and apoptotic markers in CCl4 injured hepatocytes cocultured model. Furthermore the cytokines pretreated MSCs also improved cell viability and enhanced hepatic and antiapoptotic markers in injured hepatocytes cocultured model as compared to untreated MSCs. In vivo data in cytokines pretreated group demonstrated greater homing of MSCs in liver, restored glycogen storage, and significant reduction in collagen, alkaline phosphatase, and bilirubin levels. TUNEL assay and real time PCR also supported our hypothesis. Therefore, cytokines pretreated MSCs were shown to have a better therapeutic potential on reduction of liver injury. These results demonstrated the potential utility of this novel idea of cytokines pretreated MSCs for the treatment of liver fibrosis.

Promoting the recovery of injured liver with poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) scaffolds loaded with umbilical cord-derived mesenchymal stem cells

Cell-based therapies are major focus of current research for treatment of liver diseases. In this study, mesenchymal stem cells were isolated from human umbilical cord Wharton's jelly (WJ-MSCs). Results confirmed that WJ-MSCs isolated in this study could express the typical MSC-specific markers and be induced to differentiate into adipocytes, osteoblasts, and chondrocytes. They could also be induced to differentiate into hepatocyte-like cells. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (PHBVHHx) is a new member of polyhydroxyalkanoate family and biodegradable polyester produced by bacteria. PHBVHHx scaffolds showed much higher cell attachment and viability than the other polymers tested. PHBVHHx scaffolds loaded with WJ-MSCs were transplanted into liver-injured mice. Liver morphology improved after 30 days of transplantation and looked similar to normal liver. Concentrations of serum alanine aminotransferase and total bilirubin were significantly lower, and albumin was significantly higher on days 14 and 30 in the WJ-MSCs+scaffold group than in the carbon tetrachloride (CCl4) group. Hematoxylin-eosin staining showed that liver had similar structure of normal liver lobules and similar size and shape of normal hepatic cells, and Masson staining demonstrated that liver had less blue staining for collagen after 30 days of transplantation. Real-time reverse transcription-polymerase chain reaction (RT-PCR) showed that the expression of the bile duct epithelial cell gene CK-19 in mouse liver is significantly lower on days 14 and 30 in the WJ-MSCs+scaffold group than in the CCl4 group. Real-time RT-PCR, immunocytochemistry, and periodic acid-Schiff staining showed that WJ-MSCs in scaffolds differentiated into hepatocyte-like cells on days 14 and 30 in the WJ-MSCs+scaffold group. Real-time RT-PCR also demonstrated that WJ-MSCs in scaffolds expressed endothelial cell genes Flk-1, vWF, and VE-cadherin on days 14 and 30 in the WJ-MSCs+scaffold group, indicating that WJ-MSCs also differentiated into endothelial-like cells. These results demonstrated that PHBVHHx scaffolds loaded with WJ-MSCs significantly promoted the recovery of injured liver and could be further studied for liver tissue engineering.

Advances in mesenchymal stem cells combined with traditional Chinese medicine therapy for liver fibrosis

Liver fibrosis is a primary cause of liver cirrhosis, and even hepatocarcinoma. Recently, the usage of mesenchymal stem cells (MSCs) has been investigated to improve liver fibrosis. It has been reported that the differentiation, proliferation and migration of MSCs can be regulated by traditional Chinese medicine treatment; however, the mechanisms are still unclear. In this article, the authors review the characteristics of MSCs such as multidirectional differentiation and homing, and its application in animal experiments and clinical trials. The authors also list areas that need further investigation, andlook at the future prospects of clinical application of MSCs.

The gap between the physiological and therapeutic roles of mesenchymal stem cells

Several investigators have cultivated marrow stromal cells and have identified a population of mesenchymal stem cells (MSCs). These cells expand extensively in vitro and exhibit multilineage differentiation potential. The lack of MSC-specific markers impedes identification of MSC functions. Further in vivo studies of these cells may elucidate the nature of MSCs. Although the nature of MSCs remains unclear, nonclonal stromal cultures are used as a source of putative MSCs for therapeutic purposes. Preclinical studies and clinical trials assumed that transplanted MSCs exert their effects through their differentiation properties or through the release of molecules that restore tissue functions and modulate immune cells. These studies reported contradictory results and failed to meet expectations. Thus, it is important to note that current protocols for MSC therapy are primarily based on the use of in vitro expanded nonclonal MSCs. Clearly defining the physiological features of in situ MSCs and the in vitro and in vivo properties of nonclonal cultures of stromal cells, which are often misidentified as pure stem cell cultures, may explain the reported failures of MSC therapy. This review will address these issues.

Ameliorative effect of bone marrow-derived stem cells on injured liver of mice infected with Schistosoma mansoni

The technique of stem cells or hepatocytes transplantation has recently improved in order to bridge the time before whole-organ liver transplantation. In the present study, unfractionated bone marrow stem cells (BMSCs) were harvested from the tibial and femoral marrow compartments of male mice, which were cultured in Dulbecco's modified Eagle's medium (DMEM) with and without hepatocyte growth factor (HGF), and then transplanted into Schistosoma mansoni-infected female mice on their 8th week post-infection. Mice were sacrificed monthly until the third month of bone marrow transplantation, serum was collected, and albumin concentration, ALT, AST, and alkaline phosphatase (ALP) activities were assayed. On the other hand, immunohistopathological and immunohistochemical changes of granuloma size and number, collagen content, and cells expressing OV-6 were detected for identification of liver fibrosis. BMSCs were shown to differentiate into hepatocyte-like cells. Serum ALT, AST, and ALP were markedly reduced in the group of mice treated with BMSCs than in the untreated control group. Also, granuloma showed a marked decrease in size and number as compared to the BMSCs untreated group. Collagen content showed marked decrease after the third month of treatment with BMSCs. On the other hand, the expression of OV-6 increased detecting the presence of newly formed hepatocytes after BMSCs treatment. BMSCs with or without HGF infusion significantly enhanced hepatic regeneration in S. mansoni-induced fibrotic liver model and have pathologic and immunohistopathologic therapeutic effects. Also, this new therapeutic trend could generate new hepatocytes to improve the overall liver functions.

Infusion of human umbilical cord‑derived mesenchymal stem cells effectively relieves liver cirrhosis in DEN‑induced rats

Cirrhosis is the long‑term outcome of chronic hepatic injury and no effective therapy is currently available for this disease. Mesenchymal stromal cells (MSCs) are multipotent cells that are easily acquired and amplified, and may be potential candidates for cell therapy against cirrhosis. This study aimed to determine the therapeutic effects of human umbilical cord‑derived MSCs (hUCMSCs) for the treatment of liver cirrhosis and identify an effective method for engrafting MSCs. The model of liver cirrhosis was established by induction of diethylnitrosamine (DEN) in rats. The isolated hUCMSCs were identified by morphology, flow cytometry and multilineage differentiation; they were injected into the vein of DEN‑induced rats at varied cell doses and infusion times. Biochemical analyses of the serum and histopathological analysis of the liver tissues were performed to evaluate the therapeutic effects of hUCMSCs in all treatment groups. The results indicated that isolated hUCMSCs were capable of self‑replication and differentiated into multiple lineages, including osteoblast‑, adipocyte‑ and hepatocyte‑like cells. Compared with the control group, administration of hUCMSCs at different cell doses and infusion times relieved DEN‑induced cirrhosis to varying degrees. The therapeutic effects of hUCMSCs on liver cirrhosis gradually improved with increased cell dose and infusion times. The improvement of cirrhosis was due to the capacity of hUCMSCs to breakdown collagen fibers in the liver. It was demonstrated that infusion of hUCMSCs effectively relieved liver cirrhosis by facilitating the breakdown of collagen fibers in a dose‑dependent manner and multiple infusions caused a relatively greater improvement in cirrhosis compared with a single infusion of hUCMSCs.

Transplantation of mesenchymal stem cells for the treatment of liver diseases, is there enough evidence?

Mesenchymal stem cells or multipotent mesenchymal stromal cells (MSCs) have been extensively investigated in small animal models to treat both acute and chronic liver injuries. Mechanisms of action are not clearly elucidated but may include their ability to differentiate into hepatocyte-like cells, to reduce inflammation, and to enhance tissue repair at the site of injury. This approach is controversial and evidence in large animals is missing. Side effects of MSC infusion such as the contribution to a fibrotic process have been reported in experimental settings. Nevertheless, MSCs moved quickly from bench to bedside and over 280 clinical trials are registered, of which 28 focus on the treatment of liver diseases. If no severe side-effects were observed so far, long-term benefits remain uncertain. More preclinical data regarding mechanisms of action, long term safety and efficacy are warranted before initiating large scale clinical application. The proposal of this review is to visit the current state of knowledge regarding mechanisms behind the therapeutic effects of MSCs in the treatment of experimental liver diseases, to address questions about efficacy and risk, and to discuss recent clinical advances involving MSC-based therapies.

Mesenchymal stem cells and Interleukin-6 attenuate liver fibrosis in mice

BACKGROUND

Mesenchymal stem cell (MSC) transplantation has emerged as a promising therapy for liver fibrosis. Issues concerning poor MSC survival and engraftment in the fibrotic liver still persist and warrant development of a strategy to increase MSC potency for liver repair. The present study was designed to examine a synergistic role for Interleukin-6 (IL-6) and MSCs therapy in the recovery of carbon tetrachloride (CCl(4)) induced injured hepatocytes in vitro and in vivo.

METHODS

Injury was induced through 3 mM and 5 mM CCl(4) treatment of cultured hepatocytes while fibrotic mouse model was established by injecting 0.5 ml/kg CCl(4) followed by treatment with IL-6 and MSCs. Effect of MSCs and IL-6 treatment on injured hepatocytes was determined by lactate dehydrogenase release, RT-PCR for (Bax, Bcl-xl, Caspase3, Cytokeratin 8, NFκB, TNF-α) and annexin V apoptotic detection. Analysis of MSC and IL-6 treatment on liver fibrosis was measured by histopathology, PAS, TUNEL and Sirius red staining, RT-PCR, and liver function tests for Bilirubin and Alkaline Phosphatase (ALP).

RESULTS

A significant reduction in LDH release and apoptosis was observed in hepatocytes treated with a combination of MSCs and IL-6 concomitant with upregulation of anti-apoptotic gene Bcl-xl expression and down regulation of bax, caspase3, NFκB and TNF-α. Adoptive transfer of MSCs in fibrotic liver pretreated with IL-6 resulted increased MSCs homing and reduced fibrosis and apoptosis. Hepatic functional assessment demonstrated reduced serum levels of Bilirubin and ALP.

CONCLUSION

Pretreatment of fibrotic liver with IL-6 improves hepatic microenvironment and primes it for MSC transplantation leading to enhanced reduction of liver injury after fibrosis. Synergistic effect of IL-6 and MSCs seems a favored therapeutic option in attenuation of liver apoptosis and fibrosis accompanied by improved liver function.

Expression and role of Toll-like receptors on human umbilical cord mesenchymal stromal cells

BACKGROUND AIMS

Toll-like receptors (TLRs) play an important role in innate and adaptive immunity by recognizing pathogen-associated molecular patterns (PAMPs).

METHODS

In the present study, we investigated the expression and role of TLRs on human umbilical cord mesenchymal stromal cells (UC-MSCs). The proliferation, differentiation and immunoregulatory activity of UC-MSCs primed with or without TLR ligands were determined.

RESULTS

At the RNA level, the expression of TLR2, 4, 6 and 9 was relatively higher than that of other TLRs. However, TLR3 and TLR4 expression were relatively higher at the protein level. UC-MSCs expressed functional TLRs by nuclear factor-κB activation and cytokine expression assay. Poly-inosinic acid:cytidylic acid [Poly(I:C)] stimulation inhibited the proliferation of UC-MSCs, but the ligand of other TLRs had no significant effect. Poly(I:C) stimulation enhanced the adipogenic differentiation capability of UC-MSCs, but lipopolysaccharide inhibited the adipogenic differentiation. Poly(I:C) and CpG-oligonucleotide promoted the immunosuppressive potentiality of UC-MSCs, accompanied with the phosphorylation of interferon regulatory factor 3 (IRF3) and increased expression of indoleamine 2,3-dioxygenase and interferon β, whereas activation of other TLR ligands (synthetic analog fibroblast-stimulating lipopeptide-1 and lipopolysaccharide) failed to affect the immunoregulatory activity of UC-MSCs.

CONCLUSIONS

Taken together, our data demonstrated that TLR activation influenced the function of UC-MSCs, which might have important implications in future efforts to explore the clinical potentials of UC-MSCs.

Lovastatin protects chondrocytes derived from Wharton's jelly of human cord against hydrogen-peroxide-induced in vitro injury

Our aim was to improve the survival and reduce the apoptosis of chondrocytes derived from mesenchymal stem cells from Wharton's jelly of human umbilical cord (WJMSCs) by Lovastatin supplementation under hydrogen-peroxide-induced injury conditions to simulate the osteoarthritic micro-environment. Chondrocytes were differentiated in vitro from WJMSCs. The cultured WJMSCs expressed CD90 (84.07%), CD105 (80.84%), OCT4 (26.90%), CD45 (0.42%) and CD34 (0.48%) as determined by flow cytometry. Increased aggregation of proteoglycans observed by Safranin-O staining accompanied by increased expression of COL2A1, ACAN, SOX9 and BGN shown by immunocytochemistry and reverse transcription with the polymerase chain reaction (PCR) confirmed the chondrogenic differentiation of the WJMSCs. The in vitro differentiated chondrocytes were subjected to oxidative stress by exposure to 200 μM hydrogen peroxide, either in the presence or absence of Lovastatin (2 μM) for 5 h. Lovastatin treatment resulted in decreased apoptosis, senescence and LDH release and in increased viability and proliferation of WJMSC-derived chondrocytes. Real time PCR analysis showed markedly up-regulated expression of prosurvival, proliferation and chondrogenic genes (BCL2L1, BCL2, AKT, PCNA, COL2A1, ACAN, SOX9 and BGN) and significantly down-regulated expression of pro-apoptotic genes (BAX, FADD) in the Lovastatin-treated group in comparison with injured cells. The reduced expression of VEGF and p53 as determined by enzyme-linked immunosorbent assay and PCR suggests the suitability of the use of Lovastatin in adjunct to WJMSC-derived chondrocytes for the treatment of osteoarthritis. We conclude that Lovastatin protects WJMSC-derived chondrocytes from hydrogen-peroxide-induced in vitro injury.

The differentiation of MSCs into functional hepatocyte-like cells in a liver biomatrix scaffold and their transplantation into liver-fibrotic mice

Hepatocytes derived from mesenchymal stem cells (MSCs) hold great potential for cell-based therapies for liver diseases. The cell-based therapies are critically dependent on the hepatic differentiation of the MSCs with a high efficiency and on a considerable scale. Recent results have shown that decellularized organs provide a three-dimensional extracellular matrix for the lineage restriction of stem cell maturation. In this study, we compared the cell proliferation and hepatic differentiation of murine MSCs in a biomatrix scaffold from rat liver and in the presence and absence growth factors (GF) with a two-dimensional substrate. In the absence or presence of GF, the dynamic cultured scaffold (DCS) stimulated the MSCs to express endodermal and hepatocyte-specific genes and proteins associated with improved functions, and the cells exhibited the ultrastructural characteristics of mature hepatocytes. When transplanted into CCl(4)-injured mice, the cells pretreated with a combination of the DCS and GF exhibited increased survival, liver function, engraftment into the host liver and further hepatic differentiation. The paracrine effect of the transplanted cells on hepatic stellate cells and native hepatocytes played a key role in the treatment of the liver pathology. These studies define an effective method that facilitates the hepatic differentiation of MSCs exhibiting extensive functions and support further research into the use of a decellularized liver matrix as a bioscaffold for liver tissue engineering.

Human decidua-derived mesenchymal stromal cells differentiate into hepatic-like cells and form functional three-dimensional structures

BACKGROUND AIMS

Previously, we have shown that human decidua-derived mesenchymal stromal cells (DMSC) are mesenchymal stromal cells (MSC) with a clonal differentiation capacity for the three embryonic layers. The endodermal capacity of DMSC was revealed by differentiation into pulmonary cells. In this study, we examined the hepatic differentiation of DMSC.

METHODS

DMSC were cultured in hepatic differentiation media or co-cultured with murine liver homogenate and analyzed with phenotypic, molecular and functional tests.

RESULTS AND CONCLUSIONS

DMSC in hepatic differentiation media changed their fibroblast morphology to a hepatocyte-like morphology and later formed a 3-dimensional (3-D) structure or hepatosphere. Moreover, the hepatocyte-like cells and the hepatospheres expressed liver-specific markers such as synthesis of albumin (ALB), hepatocyte growth factor receptor (HGFR), α-fetoprotein (AFP) and cytokeratin-18 (CK-18), and exhibited hepatic functions including glycogen storage capacity and indocyanine green (ICG) uptake/secretion. Human DMSC co-cultured with murine liver tissue homogenate in a non-contact in vitro system showed hepatic differentiation, as evidenced by expression of AFP and ALB genes. The switch in the expression of these two genes resembled liver development. Indeed, the decrease in AFP and increase in ALB expression throughout the co-culture were consistent with the expression pattern observed during normal liver organogenesis in the embryo. Interestingly, AFP and ALB expression was significantly higher when DMSC were co-cultured with injured liver tissue, indicating that DMSC respond differently under normal and pathologic micro-environmental conditions. In conclusion, DMSC-derived hepatospheres and DMSC co-cultured with liver homogenate could be suitable in vitro models for toxicologic, developmental and pre-clinical hepatic regeneration studies.

Adult stem cell mobilization enhances intramembranous bone regeneration: a pilot study

BACKGROUND

Stem cell mobilization, which is defined as the forced egress of stem cells from the bone marrow to the peripheral blood (PB) using chemokine receptor agonists, is an emerging concept for enhancing tissue regeneration. However, the effect of stem cell mobilization by a single injection of the C-X-C chemokine receptor type 4 (CXCR4) antagonist AMD3100 on intramembranous bone regeneration is unclear.

QUESTIONS/PURPOSES

We therefore asked: Does AMD3100 mobilize adult stem cells in C57BL/6 mice? Are stem cells mobilized to the PB after marrow ablation? And does AMD3100 enhance bone regeneration?

METHODS

Female C57BL/6 mice underwent femoral marrow ablation surgery alone (n = 25), systemic injection of AMD3100 alone (n = 15), or surgery plus AMD3100 (n = 57). We used colony-forming unit assays, flow cytometry, and micro-CT to investigate mobilization of mesenchymal stem cells, endothelial progenitor cells, and hematopoietic stem cells to the PB and bone regeneration.

RESULTS

AMD3100 induced mobilization of stem cells to the PB, resulting in a 40-fold increase in mesenchymal stem cells. The marrow ablation injury mobilized all three cell types to the PB over time. Administration of AMD3100 led to a 60% increase in bone regeneration at Day 21.

CONCLUSIONS

A single injection of a CXCR4 antagonist lead to stem cell mobilization and enhanced bone volume in the mouse marrow ablation model of intramembranous bone regeneration.

Mesenchymal stem cells relieve fibrosis of Schistosoma japonicum-induced mouse liver injury

Mesenchymal stem cells (MSCs) have gained popularity for their potential as seed cells to treat various human diseases, including pathogenic infections. Schistosoma japonicum (S. japonicum) infection is characterized by formation of parasite egg granulomas and host liver fibrosis. MSCs have been proposed as useful treatments of S. japonicum infection, but the efficacy and underlying mechanisms remain unknown. Herein, we report that MSCs were able to ameliorate S. japonicum-induced liver injury in vivo and this effect was enhanced by combining MSCs with conventional drug praziquantel (PZQ). Kunming strains of mice were infected with S. japonicum and treated with vehicle, MSCs, PZQ or PZQ + MSCs. MSC treatment not only prolonged the survival time of infected mice but reduced egg granuloma diameter and decreased the concentrations of serum transforming growth factor-β1 and hyaluronic acid. MSC treatment also inhibited collagen deposition and reduced the expression of collagen type 3, α-smooth muscle actin and vimentin in infected mouse liver tissues. Collectively, our findings suggest that MSC treatment represents a novel therapeutic approach for S. japonicum-induced liver injury and fibrosis.

Bone marrow derived mesenchymal stem cells from aged mice have reduced wound healing, angiogenesis, proliferation and anti-apoptosis capabilities

Decline in the function of stem cells with age, such as other cells of the body, results in an imbalance between loss and renewal. Increasing age of the donor thus diminishes the effectiveness of MSCs (mesenchymal stem cells) transplantation in age-related diseases. The clinical use of stem cell therapies needs autologous stem cell transplantation; it is essential therefore to study the repair ability and survivability of cells before transplantation. Bone marrow derived MSCs possess multi-lineage differentiation potential, but aging adversely affects their therapeutic efficacy. MSCs from young (2-3 months) and aged (23-24 months) GFP (green fluorescent protein)-expressing C57BL/6 mice were isolated and their regenerative potential was assessed in vitro. Real-time RT-PCR (reverse transcriptase-PCR) showed significantly higher expression of Sirt1 in MSCs isolated from young than older animals. Down-regulation of VEGF (vascular endothelial growth factor), SDF-1 (stromal-cell-derived factor 1), AKT (also known as protein kinase B) and up-regulation of p53, p21, Bax and p16 occurred in aged cells. Tube formation, wound healing and proliferative abilities of the young MSCs were better than the aged MSCs. The results suggest that age-related increased expression of apoptotic and senescent genes, with concomitant decrease in Sirt1 gene expression, inhibits to some extent stem cell functioning.

Progress in research of differentiation of mesenchymal stem cells into functional hepatocytes

Mesenchymal stem cells (MSCs) are a group of stem cells deriving from mesodermal mesenchyme. They can be recovered from a variety of tissues, including bone marrow, umbilical cord tissue, umbilical cord blood, peripheral blood and adipose tissue. Under given conditions, MSCs can differentiate into bone, fat, nerve cells, hepatocytes and many other cells, and thus can be used as a new treatment to substitute for organ transplantation. In recent years, the incidence of end-stage liver disease has been increasing and it has become one of the major diseases affecting human health. Donor scarcity and immunological rejection limit the clinical application of liver transplantation. Numerous studies have confirmed the therapeutic effects of MSCs on hepatic fibrosis, cirrhosis and other liver diseases, which may be related to the differentiation of MSCs into functional hepatocytes. This paper reviews the capacity, regulation and molecular mechanism of MSC differentiation and discusses the therapeutic effects of different sources of stem cells for liver fibrosis.

Current Applications of Human Pluripotent Stem Cells: Possibilities and Challenges

Stem cells are self-renewable cells with the differentiation capacity to develop into somatic cells with biological functions. This ability to sustain a renewable source of multi- and/or pluripotential differentiation has brought new hope to the field of regenerative medicine in terms of cell therapy and tissue engineering. Moreover, stem cells are invaluable tools as in vitro models for studying diverse fields, from basic scientific questions such as developmental processes and lineage commitment, to practical application including drug screening and testing. The stem cells with widest differentiation potential are pluripotent stem cells (PSCs), which are rare cells with the ability to generate somatic cells from all three germ layers. PSCs are considered the most optimal choice for therapeutic potential of stem cells, bringing new impetus to the field of regenerative medicine. In this article, we discuss the therapeutic potential of human PSCs (hPSCs) including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), reviewing the current preclinical and clinical data using these stem cells. We describe the classification of different sources of hPSCs, ongoing research, and currently encountered clinical obstacles of these novel and versatile human stem cells.

Nitric oxide augments mesenchymal stem cell ability to repair liver fibrosis

Background

Liver fibrosis is a major health problem worldwide and poses a serious obstacle for cell based therapies. Mesenchymal stem cells (MSCs) are multipotent and important candidate cells for future clinical applications however success of MSC therapy depends upon their homing and survival in recipient organs. This study was designed to improve the repair potential of MSCs by transplanting them in sodium nitroprusside (SNP) pretreated mice with CCl₄ induced liver fibrosis.

Methods

SNP 100 mM, a nitric oxide (NO) donor, was administered twice a week for 4 weeks to CCl₄-injured mice. MSCs were isolated from C57BL/6 wild type mice and transplanted in the left lateral lobe of the liver in experimental animals. After 4 weeks, animals were sacrificed and liver improvement was analyzed. Analysis of fibrosis by qRT-PCR and sirius red staining, homing, bilirubin and alkaline phosphatase (ALP) serum levels between different treatment groups were compared to control.

Results

Liver histology demonstrated enhanced MSCs homing in SNP-MSCs group compared to MSCs group. The gene expression of fibrotic markers; αSMA, collagen 1α1, TIMP, NFκB and iNOS was down regulated while cytokeratin 18, albumin and eNOS was up-regulated in SNP-MSCs group. Combine treatment sequentially reduced fibrosis in SNP-MSCs treated liver compared to the other treatment groups. These results were also comparable with reduced serum levels of bilirubin and ALP observed in SNP-MSCs treated group.

Conclusion

This study demonstrated that NO effectively augments MSC ability to repair liver fibrosis induced by CCl₄ in mice and therefore is a better treatment regimen to reduce liver fibrosis.

Influence of inflammation on the efficacy of mesenchymal stem cell transplantation for acute liver injury

AIM: To evaluate the influence of inflammatory reaction on the survival of transplanted mesenchymal stem cells (MSCs) and on the efficacy of MSC transplantation for acute liver injury.

METHODS: Sixteen Chinese experimental mini-pigs were randomly divided into two groups: control group and MSC transplantation group. All the animals were given 0.25 g/kg and 0.35 g/kg of D-galactosamine (D-gal) to induce acute liver injury with inflammatory reaction of varying degrees. In the control group, 100 mL of normal saline was injected into the liver via the portal vein 24 h after model induction. In the MSC transplantation group, 8 × 10⁷ MSCs (in 40 mL PBS) were injected into the liver via the portal vein. Liver function, serum inflammatory markers, survival of MSCs and pathological changes were examined after injection.

RESULTS: Serum levels of inflammation factors (IL-1, TNF-alpha) were significantly higher in the high-concentration D-gal group than in the low-concentration group. For animals given low-concentration D-gal, serum ALT, TB and NH3 differed significantly between the MSC transplantation group and control group (D2: 232.6 ± 57.6 vs 334.4 ± 42.3, 12.2 ± 3.3 vs 16.0 ± 1.2, 79.7 ± 9.3 vs 127.8 ± 28.2, all P < 0. 05). In contrast, for animals given high-concentration D-gal, there was no difference in the above parameters between the MSC transplantation group and control group. Hepatic engraftment of MSCs in the mild inflammation group was obviously different from that in the severe inflammation group, and the growth of hepatocytes was significantly improved in the mild inflammation group compared to the severe inflammation group.

CONCLUSION: MSC transplantation is at least partially useful for the management of acute liver injury. Severe inflammatory reaction is harmful to hepatic engraftment of MSCs, while mild inflammatory reaction is useful for the transplanted cells.

Bone marrow cells ameliorate liver fibrosis and express albumin after transplantation in CCl₄-induced fibrotic liver

BACKGROUND/AIM

We investigated the effect of bone marrow-derived stem cell (BMSC) transplantation on carbon tetrachloride (CCl 4 )-induced liver fibrosis.

PATIENTS AND METHODS

BMSCs of green fluorescent protein (GFP) mice were transplanted into 4-week CCl 4 -treated C57BL/6 mice directly to the liver, and the mice were treated for 4 more weeks with CCl 4 (total, 8 weeks). After sacrificing the animals, quantitative data of percentage fibrosis area and the number of cells expressing albumin was obtained. One-way analysis of variance was applied to calculate the significance of the data.

RESULTS

GFP expressing cells clearly indicated migrated BMSCs with strong expression of albumin after 28 days post-transplantation shown by anti-albumin antibody. Double fluorescent immunohistochemistry showed reduced expression of αSMA on GFP-positive cells. Four weeks after BMSC transplantation, mice had significantly reduced liver fibrosis as compared with that of mice treated with CCl 4 assessed by Sirius red staining.

CONCLUSION

Mice with BMSC transplantation with continuous CCl 4 injection had reduced liver fibrosis and a significantly improved expression of albumin compared with mice treated with CCl 4 alone. These findings strengthen the concept of cellular therapy in liver fibrosis.