Transplantation of bioencapsulated bone marrow stem cells improves hepatic regeneration and survival of 90% hepatectomized rats: a preliminary report

Direct Differentiation of Human Embryonic Stem Cells to 3D Functional Hepatocyte-like Cells in Alginate Microencapsulation Sphere

BACKGROUND

The lack of a stable source of hepatocytes is one of major limitations in hepatocyte transplantation and clinical applications of a bioartificial liver. Human embryonic stem cells (hESCs) with a high degree of self-renewal and totipotency are a potentially limitless source of a variety of cell lineages, including hepatocytes. Many techniques have been developed for effective differentiation of hESCs into functional hepatocyte-like cells. However, the application of hESC-derived hepatocyte-like cells (hESC-Heps) in the clinic has been constrained by the low yield of fully differentiated cells, small-scale culture, difficulties in harvesting, and immunologic graft rejection. To resolve these shortcomings, we developed a novel 3D differentiation system involving alginate-microencapsulated spheres to improve current hepatic differentiation, providing ready-to-use hESC-Heps.

METHODS

In this study, we used alginate microencapsulation technology to differentiate human embryonic stem cells into hepatocyte-like cells (hESC-Heps). Hepatic markers of hESC-Heps were examined by qPCR and Western blotting, and hepatic functions of hESC-Heps were evaluated by indocyanine-green uptake and release, and ammonia removal.

RESULTS

The maturity and hepatic functions of the hESC-Heps derived from this 3D system were better than those derived from 2D culture. Hepatocyte-enriched genes, such as HNF4α, AFP, and ALB, were expressed at higher levels in 3D hESC-Heps than in 2D hESC-Heps. 3D hESC-Heps could metabolize indocyanine green and had better capacity to scavenge ammonia. In addition, the 3D sodium alginate hydrogel microspheres could block viral entry into the microspheres, and thus protect hESC-Heps in 3D microspheres from viral infection.

CONCLUSION

We developed a novel 3D differentiation system for differentiating hESCs into hepatocyte-like cells by using alginate microcapsules.

Artificial liver research output and citations from 2004 to 2017: a bibliometric analysis

Background

Researches on artificial livers greatly contribute to the clinical treatments for liver failure. This study aimed to evaluate the research output of artificial livers and citations from 2004 to 2017 through a bibliometric analysis.

Methods

A list of included articles on artificial livers were generated after a comprehensive search of the Web of Science Core Collection (from 2004 to 2017) with the following basic information: number of publications, citations, publication year, country of origin, authors and authorship, funding source, journals, institutions, keywords, and research area.

Results

A total of 968 included articles ranged from 47 citations to 394 citations with a fluctuation. The publications were distributed in 12 countries, led by China (n = 212) and the US (n = 207). There were strong correlations of the number of citations with authors (r ² = 0.133, p < 0.001), and countries (r ² = 0.275, p < 0.001), while no correlations of the number of citations with the years since publication (r ² = 0.016, p = 0.216), and funding (r ² < 0.001, p = 0.770) were identified. Keyword analysis demonstrated that with the specific change of "acute liver failure," decrease in "bioartificial livers" and "hepatocyte," and increase in "tissue engineering" were identified. The top 53 cited keyword and keyword plus (including some duplicates counts) were identified, led by bioartificial liver (405 citations) and hepatocyte (248 citations). The top 50 cited keywords bursts were mainly "Blood" (2004-2008), "hepatocyte like cell" (2008-2015), and "tissue engineering" (2014-2017). All keywords could be classified into four categories: bioartificial livers (57.40%), blood purification (25.00%), clinical (14.81%), and other artificial organs (2.78%).

Discussion

This study shows the process and tendency of artificial liver research with a comprehensive analysis on artificial livers. However, although it seems that the future of artificial livers seems brighter for hepatocyte transplantation, the systems of artificial livers now are inclined on focusing on blood purification, plasma exchange, etc.

Encapsulated Whole Bone Marrow Cells Improve Survival in Wistar Rats after 90% Partial Hepatectomy

Background and Aims. The use of bone marrow cells has been suggested as an alternative treatment for acute liver failure. In this study, we investigate the effect of encapsulated whole bone marrow cells in a liver failure model. Methods. Encapsulated cells or empty capsules were implanted in rats submitted to 90% partial hepatectomy. The survival rate was assessed. Another group was euthanized at 6, 12, 24, 48, and 72 hours after hepatectomy to study expression of cytokines and growth factors. Results. Whole bone marrow group showed a higher than 10 days survival rate compared to empty capsules group. Gene expression related to early phase of liver regeneration at 6 hours after hepatectomy was decreased in encapsulated cells group, whereas genes related to regeneration were increased at 12, 24, and 48 hours. Whole bone marrow group showed lower regeneration rate at 72 hours and higher expression and activity of caspase 3. In contrast, lysosomal-β-glucuronidase activity was elevated in empty capsules group. Conclusions. The results show that encapsulated whole bone marrow cells reduce the expression of genes involved in liver regeneration and increase those responsible for ending hepatocyte division. In addition, these cells favor apoptotic cell death and decrease necrosis, thus increasing survival.

Migration of human umbilical cord blood cells into rat liver

BACKGROUND AND OBJECTIVES

Cell therapy provides an effective strategy for the treatment of an impaired liver. Human umbilical cord blood progenitor cells have the potential to differentiate into hepatocytes. Progenitor cells transplanted into the spleen could migrate directly into the liver through portal circulation. To track migration of human umbilical cord blood progenitor cells in cirrhotic rat liver after intrasplenic transplantation and to prove the possibility similar behavior of human umbilical cord blood nucleated cells in humans.

METHODS AND RESULTS

Umbilical cord blood samples from full-term deliveries will be collected after obtaining an informed consent from the mother. The collection procedure will be conducted after completion of delivery and will not interfere with the normal obstetric procedures. Adult male Sprague Dawley rats were subjected to liver cirrhosis by intraperitoneal injection of thioacetamide. Cirrhotic rats were treated with human umbilical cord blood nucleated cells by intra-splenic transplantation. Migration of intrasplenic transplanted human umbilical cord blood cells to the liver was successfully documented with Immunohistochemistry. The liver and spleen from recipient animals were removed. Histopathological and immunohistochemical analysis were performed 20 weeks after intrasplenic injection of the cells. Intrasplenically injected cells migrate to the liver of recipient animals.

CONCLUSIONS

Human cord blood nucleated cells have the potential to differentiate into hepatocytes and substantially improve the histology and function of the cirrhotic liver in rats. Relocation into liver after intrasplenic transplantation could be detected by immunohistochemistry. Transdifferentiated cells could be efficiently stained with antihuman hepatocytes.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Artificial cell microencapsulated stem cells in regenerative medicine, tissue engineering and cell therapy

Adult stem cells, especially isolated from bone marrow, have been extensively investigated in recent years. Studies focus on their multiple plasticity oftransdifferentiating into various cell lineages and on their potential in cellular therapy in regenerative medicine. In many cases, there is the need for tissue engineering manipulation. Among the different approaches of stem cells tissue engineering, microencapsulation can immobilize stem cells to provide a favorable microenvironment for stem cells survival and functioning. Furthermore, microencapsulated stem cells are immunoisolated after transplantation. We show that one intraperitoneal injection of microencapsulated bone marrow stem cells can prolong the survival of liver failure rat models with 90% of the liver removed surgically. In addition to transdifferentiation, bone marrow stem cells can act as feeder cells. For example, when coencapsulated with hepatocytes, stem cells can increase the viability and function of the hepatocytes in vitro and in vivo.

Therapeutic potential of adult bone marrow stem cells in liver disease and delivery approaches

Hematopoietic stem cells (HSCs) and mesenchymal stem cell (MSCs) are two main subtypes of bone marrow stem cells. Extensive studies have been carried out to investigate the therapeutic potential of BMSCs in liver disease. A number of animal and human studies demonstrated that either HSCs or MSCs could be applied to therapeutic purposes in certain liver diseases. The diseased liver may recruit migratory stem cells, particularly from the bone marrow, to generate hepatocyte-like cells either by transdifferentiation or cell fusion. Transplantation of BMSCs has therapeutic effects of restoration of liver mass and function, alleviation of fibrosis and correction of inherited liver diseases. There are still controversial results over the potential effects of BMSCs on liver diseases, and some of the discrepancies are thought to be lied in the differences of experimental protocols, differences in individual research laboratory, and the uncertainties of the techniques employed. Several potential approaches for BMSCs delivery in liver diseases have been proposed in animal studies and human trials. BMSCs can be delivered via intraportal vein, systemic infusion, intraperitoneal, intrahepatic, intrasplenic. The optimal stem cells delivery should be easy to perform, less invasive and traumatic, minimum side effects, and with high cells survival rate. In this review, we focus on the up-to-date evidence of therapeutic effects of BMSCs on liver disease, the characteristics of various delivery approaches, and the considerations for future studies.

In vivo expression of hepatocyte growth factor promotes differentiation of stem cells from umbilical cord blood into hepatocyte-like cells

AIM: To observe the hepatocyte growth factor-induced differentiation of CD34⁺ hematopoietic stem cells (HSC) from umbilical cord blood into hepatocyte-like cells.

METHODS: Systemic administration of naked plasmid containing HGF cDNA driven under cytomegalovirus promoter (pCMV-HGF) were injected rapidly via the tail vein of the NOD/SCID mice, and the level of HGF protein in the peripheral blood was detected by enzyme-linked immunosorbent assay. CD34⁺ human hematopoietic stem cells were isolated from umbilical cord blood by magnetic cell sorting method. 20 μL CCl₄ was administered into the mice to establish the model of acute liver damage and hepatocyte proliferation. pCMV-HGF injection and/or CD34⁺ human hematopoietic stem cells transplantation were performed on the model mice. Then the mortality of the mice and liver function recovery status were observed. Human specific mRNA and protein were also detected in the mice by reverse transcription polymerase chain reaction and immunohistochemistry, respectively (RT-PCR).

RESULTS: A remarkable enhancement of human HGF protein level was observed in the peripheral blood of the mice. The mortality and status of liver function were not significantly different between each experiment group. Path-ological examination showed that the mice received combined treatment HGF and HSC had the lightest liver injury, while the liver injury was not markedly different between the mice received HGF and HSC alone. Human albumin mRNA and protein were all expressed in the liver tissues underwent HSC transplantation with or without HGF, while in the mice with HGF injection, there were much more hepatocyte-like cells.

CONCLUSION: Stem cells from umbilical cord blood can differentiate into hepatocyte-like cells, and HGF can promote this process.