Role of stem cells in repair of liver injury: Experimental and clinical benefit of transferred stem cells on liver failure

Clinical characteristics and prognosis of patients with early sepsis-related liver injury in Northeast China

Background: Sepsis-associated liver injury (SALI) occurs in about a third of septic patients, and it is often a poor prognostic factor. However, there are few studies on early SALI and its impact on the clinical course of sepsis. Here we explored the clinical characteristics, risk factors, and prognosis of early SALI. Methods: Two hundred and one patients with confirmed sepsis were divided into those with and without early SALI (on admission) based on liver function. The clinical characteristics and prognosis were compared between groups and associated factors identified by multivariable regression analysis. Results: Sepsis-related liver injury was present in 18.9% of septic patients on admission. High aspartate transaminase (AST), high direct bilirubin, and low plasma thromboplastin antecedent (PTA, factor XI) were risk factors for sepsis with SALI: the area under the AST curve was 0.825, corresponding to a sensitivity of 0.67 and a specificity of 0.93 (cutoff 91.6 U/L), the area under the direct bilirubin curve was 0.86, corresponding to a sensitivity of 0.83 and a specificity of 0.71 (cutoff 8.35 μmol/L), and the area under the PTA curve was 0.678, corresponding to a sensitivity of 0.47 and a specificity of 0.93 (cutoff 54.0). Conclusion: Septic patients with early SALI have early-onset coagulation disorders that must be recognized to instigate early intervention and halt sepsis progression. Elevated AST, PTA, and direct bilirubin may be independent risk markers of sepsis-related liver injury, and extra clinical vigilance is required when these factors are noted in patients with sepsis.

Gold Nanoparticles Down-Regulate Alpha Fetoprotein Expression Induced by Meloxicam Hepatotoxicity in Adult Male Albino Rats: Histological and Immunohistochemical Study

Background

Meloxicam is a non-steroidal anti-inflammatory drug most commonly used for the treatment of arthritis. Meloxicam decreases prostaglandin E2 resulting in an increase in free radical concentration within the cell. Alpha-fetoprotein (AFP) is a protein produced normally by the fetal liver in hepatoblasts. In inflammatory conditions, the adult liver synthesizes AFP by regenerating cells. Gold nanoparticles (AuNPs) in the medical field, represent one of the most commonly studied metal nanoparticles which have antioxidant properties.

Objective

This study was conducted to evaluate the possible therapeutic effects of AuNPs on Meloxicam induced degenerative changes in rat liver.

Materials and Methods

fifty adult male albino rats were divided into 8 groups: The first group (control); the AuNPs group was treated with AuNPs daily for 2 weeks. The MEL 2w& MEL 2m groups were treated with meloxicam daily for 2 weeks and 2 months respectively. The MEL2w+AuNPs & MEL2m+AuNPs groups received AuNPs for 2 weeks after meloxicam injection daily for 2 weeks and 2 months respectively. The MEL2w+SAL & MEL2m+SAL groups were given meloxicam for 2 weeks and 2 months respectively followed by saline injection for 2 weeks. Histological changes, AuNPs localization in the liver by silver nitrate stain, and AFP immunoexpression were studied.

Results

Time dependent Degenerative changes and increased AFP expression were observed in the liver after meloxicam injection. However, AuNPs ameliorated these changes and decreased AFP expression. AuNPs were detected in Kupffer cells.

Conclusion

AuNPs could ameliorate meloxicam-induced toxicity in the liver and decrease AFP expression because AuNPs act as free radical scavengers which accumulate in Kupffer cells.

The Off-Treatment Effects of Olpasiran on Lipoprotein(a) Lowering: OCEAN(a)-DOSE Extension Period Results

BACKGROUND

Olpasiran, a small interfering RNA (siRNA), blocks lipoprotein(a) (Lp(a)) production by preventing translation of apolipoprotein(a) mRNA. In phase 2, higher doses of olpasiran every 12 weeks (Q12W) reduced circulating Lp(a) by >95%.

OBJECTIVES

This study sought to assess the timing of return of Lp(a) to baseline after discontinuation of olpasiran, as well as longer-term safety.

METHODS

OCEAN(a)-DOSE (Olpasiran Trials of Cardiovascular Events And LipoproteiN[a] Reduction-DOSE Finding Study) was a phase 2, dose-finding trial that enrolled 281 participants with atherosclerotic cardiovascular disease and Lp(a) >150 nmol/L to 1 of 4 active doses of olpasiran vs placebo (10 mg, 75 mg, 225 mg Q12W, or an exploratory dose of 225 mg Q24W given subcutaneously). The last dose of olpasiran was administered at week 36; after week 48, there was an extended off-treatment follow-up period for a minimum of 24 weeks.

RESULTS

A total of 276 (98.2%) participants entered the off-treatment follow-up period. The median study exposure (treatment combined with off-treatment phases) was 86 weeks (Q1-Q3: 79-99 weeks). For the 75 mg Q12W dose, the off-treatment placebo-adjusted mean percent change from baseline in Lp(a) was -76.2%, -53.0%, -44.0%, and -27.9% at 60, 72, 84, and 96 weeks, respectively (all P < 0.001). The respective off-treatment changes in Lp(a) for the 225 mg Q12W dose were -84.4%, -61.6%, -52.2%, and -36.4% (all P < 0.001). During the extension follow-up phase, no new safety concerns were identified.

CONCLUSIONS

Olpasiran is a potent siRNA with prolonged effects on Lp(a) lowering. Participants receiving doses ≥75 mg Q12W sustained a ∼40% to 50% reduction in Lp(a) levels close to 1 year after the last dose. (Olpasiran Trials of Cardiovascular Events And LipoproteiN[a] Reduction-DOSE Finding Study [OCEAN(a)-DOSE]; NCT04270760).

Cell therapy in end-stage liver disease: replace and remodel

Liver disease is prevalent worldwide. When it reaches the end stage, mortality rises to 50% or more. Although liver transplantation has emerged as the most efficient treatment for end-stage liver disease, its application has been limited by the scarcity of donor livers. The lack of acceptable donor organs implies that patients are at high risk while waiting for suitable livers. In this scenario, cell therapy has emerged as a promising treatment approach. Most of the time, transplanted cells can replace host hepatocytes and remodel the hepatic microenvironment. For instance, hepatocytes derived from donor livers or stem cells colonize and proliferate in the liver, can replace host hepatocytes, and restore liver function. Other cellular therapy candidates, such as macrophages and mesenchymal stem cells, can remodel the hepatic microenvironment, thereby repairing the damaged liver. In recent years, cell therapy has transitioned from animal research to early human studies. In this review, we will discuss cell therapy in end-stage liver disease treatment, especially focusing on various cell types utilized for cell transplantation, and elucidate the processes involved. Furthermore, we will also summarize the practical obstacles of cell therapy and offer potential solutions.

Collagen matrix scaffolds: Future perspectives for the management of chronic liver diseases

Approximately 1.5 billion chronic liver disease (CLD) cases have been estimated worldwide, encompassing a wide range of liver damage severities. Moreover, liver disease causes approximately 1.75 million deaths per year. CLD is typically characterized by the silent and progressive deterioration of liver parenchyma due to an incessant inflammatory process, cell death, over deposition of extracellular matrix proteins, and dysregulated regeneration. Overall, these processes impair the correct function of this vital organ. Cirrhosis and liver cancer are the main complications of CLD, which accounts for 3.5% of all deaths worldwide. Liver transplantation is the optimal therapeutic option for advanced liver damage. The liver is one of the most common organs transplanted; however, only 10% of liver transplants are successful. In this context, regenerative medicine has made significant progress in the design of biomaterials, such as collagen matrix scaffolds, to address the limitations of organ transplantation (e.g., low donation rates and biocompatibility). Thus, it remains crucial to continue with experimental and clinical studies to validate the use of collagen matrix scaffolds in liver disease.

Role of Mesenchymal Stem/Stromal Cells in Modulating Ischemia/Reperfusion Injury: Current State of the Art and Future Perspectives

Ischemia/reperfusion injury (IRI) is a multistep damage that occurs in several tissues when a blood flow interruption is inevitable, such as during organ surgery or transplantation. It is responsible for cell death and tissue dysfunction, thus leading, in the case of transplantation, to organ rejection. IRI takes place during reperfusion, i.e., when blood flow is restored, by activating inflammation and reactive oxygen species (ROS) production, causing mitochondrial damage and apoptosis of parenchymal cells. Unfortunately, none of the therapies currently in use are definitive, prompting the need for new therapeutic approaches. Scientific evidence has proven that mesenchymal stem/stromal cells (MSCs) can reduce inflammation and ROS, prompting this cellular therapy to also be investigated for treatment of IRI. Moreover, it has been shown that MSC therapeutic effects were mediated in part by their secretome, which appears to be involved in immune regulation and tissue repair. For these reasons, mediated MSC paracrine function might be key for injury amelioration upon IRI damage. In this review, we highlight the scientific literature on the potential beneficial use of MSCs and their products for improving IRI outcomes in different tissues/organs, focusing in particular on the paracrine effects mediated by MSCs, and on the molecular mechanisms behind these effects.

Regenerative medicine: postnatal approaches

Paper 2 of the paediatric regenerative medicine Series focuses on recent advances in postnatal approaches. New gene, cell, and niche-based technologies and their combinations allow structural and functional reconstitution and simulation of complex postnatal cell, tissue, and organ hierarchies. Organoid and tissue engineering advances provide human disease models and novel treatments for both rare paediatric diseases and common diseases affecting all ages, such as COVID-19. Preclinical studies for gastrointestinal disorders are directed towards oesophageal replacement, short bowel syndrome, enteric neuropathy, biliary atresia, and chronic end-stage liver failure. For respiratory diseases, beside the first human tracheal replacement, more complex tissue engineering represents a promising solution to generate transplantable lungs. Genitourinary tissue replacement and expansion usually involve application of biocompatible scaffolds seeded with patient-derived cells. Gene and cell therapy approaches seem appropriate for rare paediatric diseases of the musculoskeletal system such as spinal muscular dystrophy, whereas congenital diseases of complex organs, such as the heart, continue to challenge new frontiers of regenerative medicine.

Bone Marrow-Derived Mesenchymal Stem Cell-Derived Exosomes Containing Gli1 Alleviate Microglial Activation and Neuronal Apoptosis In Vitro and in a Mouse Parkinson Disease Model by Direct Inhibition of Sp1 Signaling

This study investigated possible therapeutic effect mechanisms of exosomes from bone marrow-derived mesenchymal stem cells (BMSC) in neuronal and microglial cells and in a Parkinson disease (PD) model. Neuronal SH-SY5Y cells and microglial HMC3 cells were subjected to 1-methyl-4-phenylpyridinium (MPP+) or LPS, respectively. The mRNA and protein expression was assessed using qRT-PCR, Western blotting, and enzyme-linked immunosorbent assay. Cell viability and apoptosis of SH-SY5Y cells were examined using the MTT assay and flow cytometry. Chromatin immunoprecipitation assays were performed to assess the binding relationship between glioma-associated oncogene homolog 1 (Gli1) and the Sp1 transcription factor promoter. BMSC-derived exosomes promoted cell proliferation and inhibited apoptosis in MPP+-treated SH-SY5Y cells and suppressed inflammatory markers in LPS-treated HMC3 cells. Sp1 knockdown decreased SH-SY5Y cell damage and HMC3 immune activation. Gli1 carried by BMSC exosomes directly bound with Sp1 to inhibit Sp1-mediated LRRK2 activation whereas exosomes secreted by Gli1-knockdown in BMSC did not. In a PD mouse model induced with MPTP, BMSC exosomes decreased neuron loss injury and the inflammatory response by inhibiting Sp1 signaling. Thus, BMSC-derived exosomal Gli1 alleviates inflammatory damage and neuronal apoptosis by inhibiting Sp1 in vitro and in vivo. These findings provide the basis for the potential clinical use of BMSC-derived exosomes in PD.

Translational Strategies to Eliminate Chronic Hepatitis B in Children: Prophylaxis and Management in East Asian Countries

Translational medical research on hepatitis B virus (HBV) infection and chronic hepatitis B (CHB) pathogenesis provides guidance on strengthening the treatment and prevention strategies of CHB. Preventing vertical transmission is the key to eliminating HBV infection in children. The understanding of HBV replication, hepatocyte turnover, and the fate of covalently closed circular DNA (cccDNA) would help establish a personalized application of the guidelines, especially concerning the discontinuation of nucleos(t)ide analog (NA) treatment in children. Transplacental leakage of HBV-infected maternal blood is suggested as the leading cause of vertical transmission. Prenatal maternal prophylaxis could diminish maternal HBV viremia at delivery, to reduce the risk of neonatal HBV infection. The meaning of the expression "no additional risk of breast milk feeding" is thereby explained. Understanding the untreated natural course of CHB in children and the course changeable by treatment is important to apply individualistic strategies and avoid the immoral selection of treatment indications. NAs with potent efficacy and a high barrier to drug resistance should be used as first-line treatment to reduce the likelihood of NA-resistant HBV development because the rate of mutant HBV emergence might count on the infected hepatocyte turnover rate in chronic HBV infection. Although elimination of intranuclear cccDNA is difficult by NAs alone, a cure is possible by human immunity and hepatocyte turnover. The reduction of intranuclear cccDNA occurs after the destruction of HBV-infected hepatocytes, non-cytolytic immune response, apoptosis of hepatocytes, and compensatory cell proliferation. Therefore, consolidation therapy after NA-induced hepatitis B e-antigen seroconversion must be necessary for a sufficient period. This review also summarizes the treatment strategies of CHB in children based on the practical application of translational research.

Hypoxia-Induced miR-210 Overexpression Promotes the Differentiation of Human-Induced Pluripotent Stem Cells to Hepatocyte-Like Cells on Random Nanofiber Poly-L-Lactic Acid/Poly (ε-Caprolactone) Scaffolds

An alternative treatment to liver transplantation includes the use of differentiated stem cells. Hypoxia has been shown to endow human-induced pluripotent stem cells (hiPSCs) with enhanced hepatic differentiation. We have investigated a new strategy for hepatocyte differentiation from hiPSCs using a three-step differentiation protocol with lentiviral overexpression of hypoxia-microRNA-210 of cells grown on a hybrid scaffold. We analyzed the transduction of the miR-210 lentiviral and definitive endoderm and pluripotency gene markers, including SRY-box 17 (SOX17), forkhead box A2 (FOXA2), and octamer-binding transcription factor 4 (OCT-4) by Real-Time PCR and fluorescent microscope. The scanning electron microscopy (SEM) examined the 3D cell morphological changes. Immunocytochemistry staining was used together with assays for aspartate aminotransferase, alanine aminotransferase, and urea secretion to analyze hepatocyte biomarkers and functional markers consisting of α-fetoprotein (AFP), low-density lipoprotein (LDL) uptake, fat accumulation, and glycogen. The flow cytometry analyzed the generation of reactive oxygen species (ROS). Compared to cells transfected with the blank lentiviral vectors as a control, overexpressing miR-210 was at higher levels in hiPSCs. The expression of endodermal genes and glycogen synthesis significantly increased in the differentiated lentiviral miR-210 cells without any differences regarding lipid storage level. Additionally, cells containing miR-210 showed a greater expression of ALB, LDL, AST, ALT, urea, and insignificant lower AFP and ROS levels after 18 days. However, SEM showed no significant differences between cells under the differentiation process and controls. In conclusion, the differentiation of hiPSCs to hepatocyte-like cells under hypoxia miR-210 may be a suitable method for cell therapy and regenerative medicine.

Therapeutic Potential of Umbilical Cord Stem Cells for Liver Regeneration

The liver is a vital organ for life and the only internal organ that is capable of natural regeneration. Although the liver has high regeneration capacity, excessive hepatocyte death can lead to liver failure. Various factors can lead to liver damage including drug abuse, some natural products, alcohol, hepatitis, and autoimmunity. Some models for studying liver injury are APAP-based model, Fas ligand (FasL), D-galactosamine/endotoxin (Gal/ET), Concanavalin A, and carbon tetrachloride-based models. The regeneration of the liver can be carried out using umbilical cord blood stem cells which have various advantages over other stem cell types used in liver transplantation. UCB-derived stem cells lack tumorigenicity, have karyotype stability and high immunomodulatory, low risk of graft versus host disease (GVHD), low risk of transmitting somatic mutations or viral infections, and low immunogenicity. They are readily available and their collection is safe and painless. This review focuses on recent development and modern trends in the use of umbilical cord stem cells for the regeneration of liver fibrosis.

Prophylactic versus therapeutic role of the transplanted CD34+ Umbilical Cord Blood Stem Cells and Wharton Jelly Mesenchymal Stem Cells in early / acute hepatic S. mansoni granulomas reversal in mice; a novel approach

PURPOSE

Praziquantel (PZQ) is the conventional antibilharzial agent. Nevertheless, no antibilharzial prophylactic agents or 100% curable therapy approved and no reported data about use of human CD34⁺ Umbilical Cord Blood Stem Cells (CD34⁺UCBSCs) or Wharton Jelly Mesenchymal Stem Cells (WJMSCs) in prevention and/or complete eradication of acute S.mansoni granulomas in liver. We aimed to study possible prophylactic vs therapeutic role of human CD34⁺UCBSCs and WJMSCs in acute hepatic bilharzial granulomas in pre vs post-infected mice.

METHODS

Seventy mice were divided into 7 groups (10 mice each): Normal, S.mansoni-infected, post-infected PZQ-treated, CD34⁺UCBSCs pre and post-infected, WJMSCs pre and post-infected. Serological, parasitological, histopathological evaluation using OCT4 & TGFB immunohistochemistry and quantitative image analysis assessment of TGFB-stained fibrogenesis in liver granulomas performed.

RESULTS

Histopathologically, surprisingly and significantly, the prophylactic pre-infection stem cells (CD34⁺UCBSCs and WJMSCs) & similarly the post-infection CD34⁺UCBSCs treatment revealed eradication/reversal of the entire granulomas and no fibrosis. Moreover, post-infection PZQ treatment showed fewer and significantly smaller granulomas than post-infection WJMSCs treatment. Nevertheless, post-infection WJMSCs exhibited non-significant less TGFB-stained fibrogenesis.

CONCLUSION

CD34⁺UCBSCs exerted the best prophylactic and therapeutic roles in prevention and complete cure of acute hepatic S.mansoni granulomas over WJMSCs and PZQ. In contrast, only pre-infection WJMSCs exhibited similar preventive (prophylactic) effect. On the contrary, post-infection WJMSCs were the worst (incompletely reversed granulomas). Post-infection Praziquantel was overall better therapeutically than WJMSCs in this regard. Accordingly, when it comes to WJMSCs application, WJMSCs are better used as a pre-infection prophylactic and preventive tool rather than a post-infection therapy. Further studies are needed.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Improves Spinal Cord Function After Injury in Rats by Activating Autophagy

Background

Spinal cord injury (SCI) is a global medical problem. The smallest membrane-bound nanovesicles, known as exosomes, have a role in complex intercellular communication systems and can be used directly as therapeutic agents by acting as important paracrine factors. Nevertheless, the use of exosomes derived from BMSCs (BMSC-Exos) to treat SCI has been less, and the specific mechanism has not yet been reported.

Methods

BMSC-Exos were characterized by TEM, NTA and Western blot. The effects of BMSC-Exos treatment were compared by SCI in vivo model and a series of in vitro experiments.

Results

BMSC-Exos were found to enhance the expression of autophagy-related proteins LC3IIB and Beclin-1 and enabled autophagosomes formation. After BMSC-Exos treatment, there was marked decline in the level of expression of proapoptotic protein cleaved caspase-3, while that of the antiapoptotic protein Bcl-2 was upregulated.

Conclusion

BMSC-Exos can attenuate neuronal apoptosis by promoting autophagy and promote the potential efficacy of functional behavior recovery in SCI rats. In summary, these findings expand the theoretical knowledge and forms a realistic route for the future treatment of SCI by BMSC-Exos.

Clinical application of stem cell in patients with end-stage liver disease: progress and challenges

End-stage liver disease (ESLD) is life-threatening disease worldwide, and patients with ESLD should be referred to liver transplantation (LT). However, the use of LT is limited by the lacking liver source, high cost and organ rejection. Thus, other alternative options have been explored. Stem cell therapy may be a potential alternative for ESLD treatment. With the potential of self-renewal and differentiation, both hepatic and extrahepatic stem cells have attracted a lot of attention. Among them, multipotent stem cells are most widely studies owing to their characteristics. Multipotent stem cells mainly consist of two subpopulations: hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Accumulating evidences have proved that either bone marrow (BM)-derived HSCs mobilized by granulocyte colony-stimulating factor or MSCs transplantation can improve the biochemical indicators of patients with ESLD. However, there are some challenges to be resolved before stem cells widely used in clinic, including the best stem cell source, the optimal route for stem cells transplantation, and the dose and frequency of stem cell injected. The purpose of this review is to discuss the potential of stem cell in liver diseases, particularly, the clinical progress and challenges of multipotent stem cells in the field of ESLD.

Osteopontin promotes rat hepatocyte proliferation both in vitro and in vivo

Aim: This study aimed to examine the effects of osteopontin (OPN) on hepatocyte growth and liver regeneration (LR). Methods: A recombinant lentivirus expressing OPN and OPN-siRNAs were used to treat BRL-3A cells, while the adenovirus expressing OPN or OPN-targeted shRNA were applied for rat primary hepatocytes. Moreover, rrOPN and OPN-Ab were added to treat BRL-3A. Next, rrOPN was administrated into rat regenerating livers. Then in vitro and in vivo assays were performed to evaluate the biological function of OPN in hepatocyte growth and LR. Results: OPN overexpression facilitated proliferation and viability of BRL-3A cells and primary hepatocytes, while OPN silencing reversed these effects. Similarly, rrOPN stimulated cell cycle progression and viability, but OPN-Ab led to cell cycle arrest and decreased viability. OPN overexpression induced the expression of p-STAT3, p-AKT and CCND1, and OPN siRNA led to reduction of p-AKT and CCND1. Furthermore, rrOPN promoted the expression of p-STAT3 and p-AKT, while OPN-Ab and PI3K/Akt inhibitor LY294002 both inhibited the expressions of p-AKT and Bcl2. Moreover, LR rate, serum IL-6 and TNF-α, Ki-67⁺ proportion and the phosphorylation of STAT3, AKT and p65 were augmented by rrOPN treatment. Conclusion: OPN promotes hepatocyte proliferation both in vitro and in vivo through STAT3 and AKT signaling pathways.

The Effect of Stem Cell Transplantation Therapy for Post Viral Chronic Liver Cell Failure on Associated Type II Diabetes Mellitus: A Pilot Study

BACKGROUND

It was observed that type II diabetes mellitus associated with chronic liver failure improved after stem cell transplantation. However, there were no adequate studies regarding this issue. The aim of this study was to evaluate the effect of stem cell transplantation on associated type II diabetes mellitus and on the liver function tests.

METHODS

This pilot study included 30 patients of post-hepatitis chronic liver failure who were classified into two groups: Group I included patients with chronic liver cell failure associated with type 2 diabetes. Group II included patients without type II diabetes. Autologous CD34+ and CD133+ stem cells were percutaneously infused into the portal vein. Responders (regarding the improvement of diabetes as well as improvement of liver condition) and non-responders were determined. Patients were followed up for one, three and six months after the intervention evaluating their three-hour glucose tolerance test, C- peptide (Fasting and postprandial), Child-Pugh score and performance score one month, three months, and six months after stem cell therapy.

RESULTS

Both synthetic and excretory functions of the liver were improved in 10 patients (66.66 %) of group I and in 12 patients (80 %) of group II. Significant improvement in the Oral Glucose Tolerance Test in the responders of both the groups was well defined from the 3rd month and this was comparable to changes in liver function tests and Child-Pugh score.

CONCLUSION

Successful stem cell therapy in chronic liver cell failure patients can improve but not cure the associating type 2 diabetes by improving insulin resistance.

Bone marrow mesenchymal stem cell-derived exosomes attenuate D-GaIN/LPS-induced hepatocyte apoptosis by activating autophagy in vitro

Background

Acute liver failure is an inflammation-mediated hepatocyte injury. Mesenchymal stem cell (MSC) transplantation is currently considered to be an effective treatment strategy for acute liver failure. Exosomes are an important paracrine factor that can be used as a direct therapeutic agent. However, the use of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) in the treatment of acute liver failure has not been reported.

Purpose

Here, we established a model of hepatocyte injury and apoptosis induced by D-galactosamine and lipopolysaccharide (D-GalN/LPS) to study the protective effect of BMSC-Exos on hepatocyte apoptosis, and further explored its protective mechanism.

Methods

BMSC-Exos was identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and Western blot. Laser confocal microscopy was used to observe the uptake of Dil-Exos by hepatocytes. D-GalN/LPS-induced primary hepatocytes were pretreated with BMSC-Exos in vitro, and then the cells were harvested. The apoptosis of hepatocytes was observed by TUNEL staining, flow cytometry and Western blot. Electron microscopy and mRFP-GFP-LC3 and Western blot was used to observe autophagy.

Results

BMSC-Exos increased the expression of autophagy marker proteins LC3 and Beclin-1 and promoted the formation of autophagosomes. After BMSC-Exos treatment, the expression levels of the proapoptotic proteins Bax and cleaved caspase-3 were significantly decreased, while the expression level of the anti-apoptotic protein Bcl-2 was upregulated. However, when the autophagy inhibitor 3MA was present, the effect of BMSC-Exos on inhibiting apoptosis was significantly reversed.

Conclusions

Our results showed for the first time that BMSC-Exos had the potential to reduce hepatocyte apoptosis after acute liver failure. In particular, we found that BMSC-Exos attenuated hepatocyte apoptosis by promoting autophagy. 

Human liver stem cells attenuate concanavalin A-induced acute liver injury by modulating myeloid-derived suppressor cells and CD4+ T cells in mice

BACKGROUND

Acute liver failure (ALF) is a serious threat to the life of people all over the world. Finding an effective way to manage ALF is important. Human liver stem cells (HLSCs) are early undifferentiated cells that have been implicated in the regeneration and functional reconstruction of the liver. In this study, we aimed to evaluate the protective effects of the HLSC line HYX1 against concanavalin A (ConA)-induced acute liver injury.

METHODS

HYX1 cells were characterized by microscopy, functional assays, gene expression, and western blot analyses. We showed that HYX1 cells can differentiate into hepatocytes. We intraperitoneally injected HYX1 cells in mice and administered ConA via caudal vein injection 3, 6, 12, 24, and 48 h later. The effects of HYX1 cell transplantation were evaluated through blood tests, histology, and flow cytometry.

RESULTS

HYX1 cells reduced the levels of alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) in serum and dramatically decreased the severity of liver injuries. Mechanistically, HYX1 cells promoted myeloid-derived suppressor cell (MDSC) migration into the spleen and liver, while reducing CD4+ T cell levels in both tissues. In addition, HYX1 cells suppressed the secretion of proinflammatory cytokines, such as tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), but led to increased interleukin-10 (IL-10) production.

CONCLUSIONS

These results confirm the efficacy of HLSCs in the prevention of the ConA-induced acute liver injury through modulation of MDSCs and CD4+ T cell migration and cytokine secretion.

Bone marrow-derived mesenchymal stem cells ameliorate liver injury in a rat model of sepsis by activating Nrf2 signaling

Sepsis is a fatal condition that leads to serious systemic inflammation and multiple organ dysfunction syndromes. This study was designed to investigate the possible therapeutic effect of bone marrow-derived mesenchymal stem cells (BMSCs) on sepsis-induced liver injury. We also aimed to examine the role of Nrf2 activation in modulating the response to sepsis following BMSCs treatment. Twenty-four adult male albino rats were assigned to: control, lipopolysaccharide (LPS) and LPS-stem cell groups. Liver samples were processed for light and electron microscope examinations. Immunohistochemical localization of BAX, proliferating cell nuclear antigen and nuclear factor-erythroid 2-related factor 2 (Nrf2) was carried out. Liver homogenates were prepared for assessment of reduced glutathione, glutathione peroxidase, tumor necrosis factor-alpha and interleukin-6 and also real-time PCR analysis of Nrf2 expression. BMSCs treatment improved the histopathological changes of the liver, enhanced tissue regeneration and decreased apoptosis following sepsis. We reported highly significant enhancement in Nrf2 expressions at mRNA and protein levels in the LPS-stem cell group compared with the LPS group. The up regulation of Nrf2 was probably implicated in decreasing inflammatory cytokine levels and counteracting oxidative stress induced by sepsis. Thus, BMSCs therapies could be a viable approach to treat sepsis-induced liver damage by activating Nrf2 signaling.

An improvised one-step sucrose cushion ultracentrifugation method for exosome isolation from culture supernatants of mesenchymal stem cells

BACKGROUND

Exosomes are nanovesicles (30-120 nm) of endosomal origin. These exosomes contain various functional proteins and RNAs that could be used for therapeutic purposes. Currently, having a standard method for exosome isolation retaining its biological properties with increased yield and purity is a major challenge. The most commonly used method is differential ultracentrifugation but it has its own disadvantages, which include high time consumption, low yield due to disruption of exosome integrity, and high protein contaminants. In this study, we have identified an improved method addressing these problems for exosome isolation using ultracentrifugation since it is cost-effective and used worldwide.

METHOD

We have compared differential ultracentrifugation with the modified method called one-step sucrose cushion ultracentrifugation for exosome isolation. The conditioned serum-free media from human mesenchymal stem cells cultured for 48 h was collected for exosome isolation. The cellular debris was removed by centrifugation at 300g for 10 min, followed by centrifugation at 10,000g for 30 min to remove microvesicles. Equal volumes of pre-processed conditioned media were used for exosome isolation by direct ultracentrifugation and one-step sucrose cushion ultracentrifugation. The exosomes isolated using these methods were characterized for their size, morphology, concentration, and surface marker protein expression.

RESULT

It was observed that the recovery of exosomes with cup-shaped morphology from one-step sucrose cushion ultracentrifugation was comparatively high as estimated by nanoparticle tracking analysis and electron microscopy. These results were confirmed by Western blotting and flow cytometry.

CONCLUSION

We conclude that this one-step sucrose cushion ultracentrifugation method provides an effective and reproducible potential standard method which could be used for various starting materials for isolating exosomes. We believe that this method will have a wide application in the field of extracellular vesicle research where exosome isolation with high yield and purity is an imperative step. Schematic representation of comparison of UC and SUC exosome isolation methods for tissue-specific human mesenchymal stem cells. The SUC isolation method yields a greater number of cup-shaped exosomes with a relatively homogenous population for mass-scale production of exosomes for downstream analysis.

ABBREVIATIONS

SUC One-step sucrose cushion ultracentrifugation, UC Direct ultracentrifugation.

Future Approaches and Therapeutic Modalities for Acute Liver Failure

The current gold standard for the management of acute liver failure is liver transplantation. However, because of organ shortages, other modalities of therapy are necessary as a possible bridge. This article discusses the current modalities as well as the future management of acute liver failure. Liver assist devices, hepatocyte transplantation, stem cell transplant, organogenesis, and repopulation of decellularized organs are discussed.

Mesenchymal Stem Cell Transplantation for Liver Cell Failure: A New Direction and Option

Background and Aims

Mesenchymal stem cell transplantation (MSCT) became available with liver failure (LF), while the advantages of MSCs remain controversial. We aimed to assess clinical advantages of MSCT in patients with LF.

Methods

Clinical researches reporting MSCT in LF patients were searched and included.

Results

Nine articles (n = 476) related with LF patients were enrolled. After MSCT, alanine aminotransferase (ALT) baseline decreased largely at half a month (P < 0.05); total bilirubin (TBIL) baseline declined to a certain stable level of 78.57 μmol/L at 2 and 3 months (P < 0.05). Notably, the decreased value (D value) of Model for End-Stage Liver Disease score (MELD) of acute-on-chronic liver failure (ACLF) group was higher than that of chronic liver failure (CLF) group (14.93 ± 1.24 versus 4.6 ± 5.66, P < 0.05). Moreover, MELD baseline of ≥20 group was a higher D value of MELD than MELD baseline of <20 group with a significant statistical difference after MSCT (P = 0.003).

Conclusion

The early assessment of the efficacy of MSCT could be based on variations of ALT at half a month and TBIL at 2 and 3 months. And it had beneficial effects for patients with LF, especially in ACLF based on the D value of MELD.

Bone marrow or adipose tissue mesenchymal stem cells: Comparison of the therapeutic potentials in mice model of acute liver failure

Acute liver failure (ALF) is a lethal disease with limited life-saving therapy. Because lack of whole organ donors for liver transplantation, a substitute treatment strategy is needed for these patients. Preclinical and clinical findings have proved that treatment with mesenchymal stem cells (MSCs) is beneficial for recovery from ALF. In this approach, however, the appropriate sources of these cells are unclear. In the present study, we investigated and compared the therapeutic potentials of bone marrow-mesenchymal stem cells (BM-MSC) with those of adipose tissue (AT-MSC) in carbon tetrachloride (CCL4)-induced acute liver failure in mice. Murine BM- and AT-MSCs obtained from normal mice were cultured and labelled. The cells were transplanted to CCL4-induced ALF mice models intravenously. After cell transplantation, blood samples and liver tissues were collected daily for 72 h to analyze liver enzymes and liver histopathology, respectively. We found that survival rate of AT-MSC transplanted (AT-TR) mice was significantly higher than that of control (ALF) group. Liver histopathology was superior in the AT-TR mice, but not significantly, compared to that in BM-MSC transplanted (BM-TR) ones. Furthermore, in the AT-TR mice the level of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), in some time points were significantly less than those of BM-TR. Taken together, these data suggest that in comparison to BM-MSC, AT-MSCs is an appropriate choice for cell therapy in the case of acute liver failure.

Current Perspectives Regarding Stem Cell-Based Therapy for Liver Cirrhosis

Liver cirrhosis is a major cause of mortality and a common end of various progressive liver diseases. Since the effective treatment is currently limited to liver transplantation, stem cell-based therapy as an alternative has attracted interest due to promising results from preclinical and clinical studies. However, there is still much to be understood regarding the precise mechanisms of action. A number of stem cells from different origins have been employed for hepatic regeneration with different degrees of success. The present review presents a synopsis of stem cell research for the treatment of patients with liver cirrhosis according to the stem cell type. Clinical trials to date are summarized briefly. Finally, issues to be resolved and future perspectives are discussed with regard to clinical applications.

Liver Regeneration: Analysis of the Main Relevant Signaling Molecules

Liver regeneration is a highly organized tissue regrowth process and is the most important reaction of the liver to injury. The overall process of liver regeneration includes three phases: priming stage, proliferative phase, and termination phase. The initial step aims to induce hepatocytes to be sensitive to growth factors with the aid of some cytokines, including TNF-α and IL-6. The proliferation phase promotes hepatocytes to re-enter G1 with the stimulation of growth factors. While during the termination stage, hepatocytes will discontinue to proliferate to maintain normal liver mass and function. Except for cytokine- and growth factor-mediated pathways involved in regulating liver regeneration, new substances and technologies emerge to influence the regenerative process. Here, we reviewed novel and important signaling molecules involved in the process of liver regeneration to provide a cue for further research.

An insight on the association of glycation with hepatocellular carcinoma

Hepato-cellular carcinoma (HCC) is one of the frequent cause of cancer-related death worldwide and dominant form of primary liver cancer. However, the reason behind a steady increase in the incidence of this form of cancer remains elusive. Glycation has been reported to play a significant role in the induction of several chronic diseases including cancer. Several risk factors that could induce HCC have been reported in the literature. Deciphering the complex patho-physiology associated with HCC is expected to provide new targets for the early detection, prevention, progression and recurrence. Even-though, some of the causative aspects of HCC is known, the advanced glycation end products (AGEs) related mechanism still needs further research. In the current manuscript, we have tried to uncover the possible role of glycation in the induction of HCC. In the light of the available scientific literature, we advocate in-depth comprehensive studies which will shed light towards mechanistic association of glycation with HCC.

Transplantation of human bone marrow mesenchymal stromal cells reduces liver fibrosis more effectively than Wharton's jelly mesenchymal stromal cells

Background

Mesenchymal stromal cells (MSCs) from various tissues have shown moderate therapeutic efficacy in reversing liver fibrosis in preclinical models. Here, we compared the relative therapeutic potential of pooled, adult human bone marrow (BM)- and neonatal Wharton’s jelly (WJ)-derived MSCs to treat CCl₄-induced liver fibrosis in rats.

Methods

Sprague-Dawley rats were injected with CCl₄ for 8 weeks to induce irreversible liver fibrosis. Ex-vivo expanded, pooled human MSCs obtained from BM and WJ were intravenously administered into rats with liver fibrosis at a dose of 10 × 10⁶ cells/animal. Sham control and vehicle-treated animals served as negative and disease controls, respectively. The animals were sacrificed at 30 and 70 days after cell transplantation and hepatic-hydroxyproline content, histopathological, and immunohistochemical analyses were performed.

Results

BM-MSCs treatment showed a marked reduction in liver fibrosis as determined by Masson’s trichrome and Sirius red staining as compared to those treated with the vehicle. Furthermore, hepatic-hydroxyproline content and percentage collagen proportionate area were found to be significantly lower in the BM-MSCs-treated group. In contrast, WJ-MSCs treatment showed less reduction of fibrosis at both time points. Immunohistochemical analysis of BM-MSCs-treated liver samples showed a reduction in α-SMA⁺ myofibroblasts and increased number of EpCAM⁺ hepatic progenitor cells, along with Ki-67⁺ and human matrix metalloprotease-1⁺ (MMP-1⁺) cells as compared to WJ-MSCs-treated rat livers.

Conclusions

Our findings suggest that BM-MSCs are more effective than WJ-MSCs in treating liver fibrosis in a CCl₄-induced model in rats. The superior therapeutic activity of BM-MSCs may be attributed to their expression of certain MMPs and angiogenic factors.

Clinical Application of Pluripotent Stem Cells: An Alternative Cell-Based Therapy for Treating Liver Diseases?

The worldwide shortage of donor livers for organ and hepatocyte transplantation has prompted the search for alternative therapies for intractable liver diseases. Cell-based therapy is envisaged as a useful therapeutic option to recover and stabilize the lost metabolic function for acute liver failure, end-stage and congenital liver diseases, or for those patients who are not considered eligible for organ transplantation. In recent years, research to identify alternative and reliable cell sources for transplantation that can be derived by reproducible methods has been encouraged. Human pluripotent stem cells (PSCs), which comprise both embryonic and induced PSCs, may offer many advantages as an alternative to hepatocytes for liver cell therapy. Their capacity for expansion, hepatic differentiation and self-renewal make them a promising source of unlimited numbers of hepatocyte-like cells for treating and repairing damaged livers. Immunogenicity and tumorigenicity of human PSCs remain the bottleneck for successful clinical application. However, recent advances made to develop disease-corrected hepatocyte-like cells from patients' human-induced PSCs by gene editing have opened up many potential gateways for the autologous treatment of hereditary liver diseases, which may likely reduce the risk of rejection and the need for lifelong immunosuppression. Well-defined methods to reduce the expression of oncogenic genes in induced PSCs, including protocols for their complete and safe hepatic differentiation, should be established to minimize the tumorigenicity of transplanted cells. On top of this, such new strategies are currently being rigorously tested and validated in preclinical studies before they can be safely transferred to clinical practice with patients.

Therapeutic potentials of mesenchymal stem cells on the renal cortex of experimentally induced hypertensive albino rats: Relevant role of Nrf2

Bone marrow derived-mesenchymal stem cells (BM-MSCs) have brought great attention in regenerative medicine field, various experimental & clinical trials were held to investigate their therapeutic effects in different disorders. We designed a histological & immunohistochemical study to evaluate effectiveness of MSCs therapy in withhold of end-stage renal disease (ESRD) secondary to hypertension which has become a growing & striking public health problem. 30 adult male albino rats were utilized, 20 of them were exposed to experimental induction of hypertension, then divided equally to MSCs treated group (injected with 1×10⁶ fluorescent labeled cell i.v./rat), while the second one was left without treatment. Renal specimens were subjected to histopathological, ultrastructural and immunohistochemical examination for Nrf2 in addition to biochemical estimation of serum urea & creatinine. Our results documented that BM-derived MSCs exerts considerable reversing effect of histopathologic and ultrastructural hypertensive nephropathy. Moreover, immunohistochemical results clearly pointed to relevant role of Nrf2 pathway in MSCs related renal therapeutic effects.

Portal Vein Embolization with Contralateral Application of Stem Cells Facilitates Increase of Future Liver Remnant Volume in Patients with Liver Metastases

OBJECTIVES

This study aimed to evaluate the progress of future liver remnant volume (FLRV) in patients with liver metastases after portal vein embolization (PVE) with the application of hematopoietic stem cells (HSCs) and compare it with a patients control group after PVE only.

METHODS

Twenty patients (group 1) underwent PVE with contralateral HSC application. Subsequently, CT volumetry with the determination of FLRV was performed at weekly intervals, in total three weeks. A sample of twenty patients (group 2) who underwent PVE without HSC application was used as a control group.

RESULTS

The mean of FLRV increased by 173.2 mL during three weeks after the PVE/HSC procedure, whereas by 98.9 mL after PVE only (p = 0.015). Furthermore, the mean daily growth of FLRV by 7.6 mL in group 1 was significantly higher in comparison with 4.1 mL in group 2 (p = 0.007).

CONCLUSIONS

PVE with the application of HSC significantly facilitates growth of FLRV in comparison with PVE only. This method could be one of the new suitable approaches to increase the resectability of liver tumours.

Involvement of hepatic macrophages in the antifibrotic effect of IGF-I-overexpressing mesenchymal stromal cells

BACKGROUND

Cirrhosis is a major health problem worldwide and new therapies are needed. Hepatic macrophages (hMø) have a pivotal role in liver fibrosis, being able to act in both its promotion and its resolution. It is well-known that mesenchymal stromal cells (MSCs) can modulate the immune/inflammatory cells. However, the effects of MSCs over hMø in the context of liver fibrosis remain unclear. We previously described evidence of the antifibrotic effects of in vivo applying MSCs, which were enhanced by forced overexpression of insulin-like growth factor 1 (AdIGF-I-MSCs). The aim of this work was to analyze the effect of MSCs on hMø behavior in the context of liver fibrosis resolution.

METHODS

Fibrosis was induced in BALB/c mice by chronic administration of thioacetamide (8 weeks). In vivo gene expression analyses, in vitro experiments using hMø isolated from the nonparenchymal liver cells fraction, and in vivo experiments with depletion of Mø were performed.

RESULTS

One day after treatment, hMø from fibrotic livers of MSCs-treated animals showed reduced pro-inflammatory and pro-fibrogenic gene expression profiles. These shifts were more pronounced in AdIGF-I-MSCs condition. This group showed a significant upregulation in the expression of arginase-1 and a higher downregulation of iNOS expression thus suggesting decreased levels of oxidative stress. An upregulation in IGF-I and HGF expression was observed in hMø from AdIGF-I-MSCs-treated mice suggesting a restorative phenotype in these cells. Factors secreted by hMø, preconditioned with MSCs supernatant, caused a reduction in the expression levels of hepatic stellate cells pro-fibrogenic and activation markers. Interestingly, hMø depletion abrogated the therapeutic effect achieved with AdIGF-I-MSCs therapy. Expression profile analyses for cell cycle markers were performed on fibrotic livers after treatment with AdIGF-I-MSCs and showed a significant regulation in genes related to DNA synthesis and repair quality control, cell cycle progression, and DNA damage/cellular stress compatible with early induction of pro-regenerative and hepatoprotective mechanisms. Moreover, depletion of hMø abrogated such effects on the expression of the most highly regulated genes.

CONCLUSIONS

Our results indicate that AdIGF-I-MSCs are able to induce a pro-fibrotic to resolutive phenotype shift on hepatic macrophages, which is a key early event driving liver fibrosis amelioration.

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.

Clinical effectiveness of cell therapies in patients with chronic liver disease and acute-on-chronic liver failure: a systematic review protocol

BACKGROUND

Chronic liver disease (CLD) is a major health burden worldwide. Liver cirrhosis, a form of CLD is the fifth most common cause of death in the UK. Acute-on-chronic liver failure (ACLF) is the result of an acute insult superimposed on patients with liver cirrhosis as a result of precipitating events such as infection or bleeding. ACLF has a high associated mortality as a result of multi-organ failure. The only effective treatment for CLD is liver transplantation, but the treatment is limited by shortage of donor organs. As a result, alternative treatments such as cell therapies have been studied in patients with liver diseases. This study will systematically review the evidence on clinical effectiveness of cell therapies in patients.

METHODS

All types of study design that investigate the effectiveness of cell therapies (haematopoietic, mesenchymal and unsorted cell types) of autologous or allogeneic origin and/or the use of granulocyte colony-stimulating factor in patients with CLD including ACLF will be included (except case reports). Both autologous and allogenic cell types will be included. The primary outcomes of interest are survival, model for end-stage liver disease score, quality of life and adverse events. Secondary outcomes include liver function tests, Child-Pugh score and events of liver decompensation. A literature search will be conducted in the following databases: MEDLINE, MEDLINE in Process, EMBASE and Cochrane Library (CENTRAL, CDSR, DARE, HTA databases). Trial registers will be searched for ongoing trials, as will conference proceedings. Reference lists of relevant articles and systematic reviews will be screened. Randomised controlled trial (RCT) evidence is likely to be scant; therefore, controlled trials and concurrently controlled observational studies will be primarily analysed and uncontrolled observational studies will be analysed where primary outcomes are not reported in the control studies or where uncontrolled studies have longer follow-up. Initial screening of studies will be carried by one reviewer with a proportion checked by another reviewer. Full-text selection will be performed by two reviewers independently against the pre-defined selection criteria. The data collection and the risk of bias assessment will be completed by one reviewer and counter checked by another reviewer for all selected studies. Where appropriate, data will be meta-analysed for each study design, therapy and outcome. Data specifically on ACLF will be treated as a subgroup.

DISCUSSION

This systematic review will identify the available evidence on the effectiveness of cell therapies in patients with CLD and in ACLF subgroup. The findings will aid decision-making by clinicians and health service leaders.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016016104.

Equal distribution of mesenchymal stem cells after hepatic ischemia-reperfusion injury

BACKGROUND

Liver ischemia-reperfusion (I/R) injury is one of the major causes of hepatocellular injury-related mortality and morbidity after liver transplantation. Mesenchymal stem cells (MSCs) have been shown to reduce liver I/R injury and improve regeneration. The purpose of the present study was to investigate the difference in the distribution of systemically delivered MSCs in the recipient's liver between the ischemic injury area and nonischemic area.

MATERIAL AND METHODS

Fishers' rats (7-8 week of age) were used as donors of MSCs and recipients. Bone marrow-derived MSCs were isolated from the donor's femur. Before systemic administration, MSCs were labeled with the fluorescent dye PKH26. The rats were divided into four groups: (1) I/R injury + MSC group, (2) MSC only, without I/R injury, (3) I/R injury + saline group, and (4) the Sham group. I/R injury was performed by clamping the inflow vascular structures of the left and middle lobes of the recipient's liver for 60 min. The right lobe was considered as a nonischemic part. Subsequently, 1.5 × 10(6) of MSCs or saline (NaCl, 0.9%) was administrated via the rat's tail vein. Thereafter, the rats were killed after days one, three, or seven for the analyses.

RESULTS

A fluorescent microscopy assay for labeled MSCs showed positive cells in both ischemic and nonischemic parts of the recipient's liver. The number of cells was significantly higher in the I/R injury + MSC group compared with the only MSC, without I/R injury group. Immunohistochemical staining showed that there was no significant difference in the proliferation of Ki-67-positive cells between the I/R + MSCs and I/R + saline groups. In addition, the serum transaminase levels were not different between the I/R + MSCs and I/R + saline groups.

CONCLUSIONS

After partial liver I/R injury, transplanted MSCs migrate equally to the ischemic and nonischemic parts of the recipient's liver. Considering the unique ability of the liver to regenerate, both parts of the liver presumably receive signals for regeneration.

Useful properties of undifferentiated mesenchymal stromal cells and adipose tissue as the source in liver-regenerative therapy studied in an animal model of severe acute fulminant hepatitis

BACKGROUND AIMS

End-stage liver diseases frequently require liver transplantation. Cell therapy could be an alternative. This study aimed to analyze whether undifferentiated mesenchymal stromal cells (U-MSCs) or MSC-derived hepatocyte-like cells (DHLCs) from adipose tissue (AT), umbilical cord blood (UCB) and bone marrow (BM) would better restore damaged liver.

METHODS

AT was obtained from lipo-aspiration, UCB from an Umbilical Cord Blood Bank and BM from a BM Transplantation Unit. AT (collagenase digestion), UCB and BM (Ficoll gradient) were cultured (Dulbecco's modified Eagle's medium, low glucose, FBS) for 3 days. Detached adherent cells, at passage 4, were characterized as MSCs. Genetic stability was investigated by means of telomerase enzyme activity and karyotype. Hepatocyte differentiation protocol was performed with the use of Dulbecco's modified Eagle's medium, hepatocyte growth factor, basic fibroblast growth factor and nicotinamide (7 days); maturation medium (oncostatin, dexamethasone, insulin, transferrin and selenium) was added at 36 days. Hepatogenesis analyses were performed by use of morphology and albumin, AF, tyrosine-aminotransferase and glutamine synthetase gene expression and quantitative reverse transcription-polymerase chain reaction on days 9, 18, 25 and 36. Functionality was assessed through glycogen storage detection, indocyanine green absorption and transplantation procedure. U-MSCs and DHLCs were injected 48 h after induced fulminant hepatitis (intraperitoneal injection of carbon tetrachloride) in SCID/BALB-c mice. Histopathologic analyses were performed on days 7 and 15. Human origin included albumin and CK19 human markers.

RESULTS

All MSCs differentiated into functional hepatocyte-like cells, stored glycogen and absorbed indocyanine green. AT-MSC DHLC gene expression was more consistent with a normal hepatogenic-differentiation profile. UCB-MSCs expanded weakly, impairing their use for the transplantation procedure. AT and BM U-MSCs and DHLCs regenerated liver injury equally. Regenerated hepatocytes exhibited human origin.

CONCLUSIONS

AT might be the source and U-MSCS the stem cells useful for liver-regenerative therapy.

Radiation responses of stem cells: targeted and non-targeted effects

Stem cells are fundamental to the development of any tissue or organism via their ability to self-renew, which is aided by their unlimited proliferative capacity and their ability to produce fully differentiated offspring, often from multiple lineages. Stems cells are long lived and have the potential to accumulate mutations, including in response to radiation exposure. It is thought that stem cells have the potential to be induced into a cancer stem cell phenotype and that these may play an important role in resistance to radiotherapy. For radiation-induced carcinogenesis, the role of targeted and non-targeted effects is unclear with tissue or origin being important. Studies of genomic instability and bystander responses have shown consistent effects in haematopoietic models. Several models of radiation have predicted that stem cells play an important role in tumour initiation and that bystander responses could play a role in proliferation and self-renewal.

Establishment of a rat model of thioacetamide induced hepatic fibrosis

AIM: To establish a stable and efficient rat model of thioacetamide (TAA) induced hepatic fibrosis.

METHODS: Male SD rats were randomly divided into a normal group and a model group. The model group was intragastrically administrated 3% TAA at 160 mg/kg body weight and the normal group was administrated distilled water. Serum and hepatic tissue samples were collected after 6 wk. Serum levels of ammonia (BAM), alkaline phosphatase (AKP), total bilirubin (TBIL), albumin/globulin (ALB/GLB) and cell factors including hepatocyte growth factor (HGF), heparin-binding epidermal growth factor (HB-EGF), interleukin-6 (IL-6), and α-smooth muscle antibody (α-SMA) were detected. Histopathological examination of liver tissue was conducted by HE staining and Masson staining, and the degree of liver fibrosis was observed under a microscope. The natural repair of hepatic fibrosis was observed by HE staining 11 wk after stopping administration of TAA.

RESULTS: The rate of hepatic fibrosis was 100% after intragastric administration of TAA for 6 wk. Compared with the control group, the liver function in the model group changed significantly; serum levels of BAM, AKP and TBIL increased significantly, and the ratio of ALB/GLB decreased significantly (P < 0.01). Serum levels of HGF and HB-EGF decreased significantly, and serum IL-6 and α-SMA increased significantly (P < 0.01). The degree of hepatic fibrosis was not changed until 11 weeks after stopping TAA.

CONCLUSION: A stable and persistent rat model of hepatic fibrosis has been successfully prepared by intragastric administration of TAA for 6 wk. This is a convenient and practical method to establish a rat liver fibrosis model with a high rate of hepatic fibrosis formation.

Bone marrow-derived mesenchymal stem cells attenuate acute liver injury and regulate the expression of fibrinogen-like-protein 1 and signal transducer and activator of transcription 3

In recent years, bone marrow-derived mesenchymal stem cells (BMSCs) have been demonstrated to exert extensive therapeutic effects on acute liver injury; however, the underlying mechanisms of these effects have remained to be elucidated. The present study focused on the potential anti-apoptotic and pro-regenerative effects of BMSCs in D-galactosamine (D-Gal) and lipopolysaccharide (LPS)-induced acute liver injury in rats. An experimental rat acute liver injury model was established by intraperitoneal injection of D-Gal (400 mg/kg) and LPS (80 μg/kg). BMSCs and an identical volume of saline were administered via the caudal vein 2 h after the D-Gal and LPS challenge. Subsequently, the serum samples were collected to detect the levels of alanine aminotransferase and aspartate aminotransferase. Hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated nick-end labeling assay and immunohistochemical staining were performed to determine apoptosis, regeneration and histological changes of liver sections. Western blotting and reverse transcription-quantitative polymerase chain reaction were performed to detect the protein and mRNA expression levels of fibrinogen-like-protein 1 (FGL1), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), STAT3 and B-cell lymphoma 2 (Bcl-2) and Bcl-2 associated X protein (Bax) in liver tissue samples. The results indicated that intravenous transplantation of BMSCs significantly decreased the levels of alanine aminotransferase and aspartate aminotransferase, and reduced hepatocellular necrosis and inflammatory cell infiltration. Additionally, a terminal deoxynucleotidyl transferase-mediated nick-end labeling assay and immunohistochemical staining revealed that BMSC treatment reduced hepatocyte apoptosis and enhanced liver regeneration. Furthermore, Bcl-2 expression was increased, whilst the protein expression of Bax was reduced. The expression of FGL1 and p-STAT3 were elevated concurrently with the improvement of liver function. These results demonstrated that BMSCs may provide a promising potential agent for the prevention of acute liver injury via inhibition of hepatocyte apoptosis and acceleration of liver regeneration. The mechanism may be, a least in part, a consequence of the upregulation of FGL1 expression and the induction of STAT3 phosphorylation.

Gene expression profiling of hematopoietic stem cells (HSCs)

Transcriptomic analysis to decipher the molecular phenotype of hematopoietic stem cells, regulatory mechanisms directing their life cycle, and the molecular signals mediating proliferation, mobilization, migration, and differentiation is believed to unravel disease-specific disturbances in hematological diseases and assist in the development of novel cell-based clinical therapies in this era of genomic medicine. The recent advent in genomic tools and technologies is now enabling the study of such comprehensive transcriptional characterization of cell types in a robust and successful manner. This chapter describes detailed protocols for isolating RNA from purified population of hematopoietic cells and gene expression profiling of those purified cells using both microarrays (Affymetrix) and RNA-Seq technology (Illumina Platform).

Cell differentiation mediated by co-culture of human umbilical cord blood stem cells with murine hepatic cells

In the present study, purified human cord blood stem cells were co-cultivated with murine hepatic alpha mouse liver 12 (AML12) cells to compare the effect on endodermal stem cell differentiation by either direct cell-cell interaction or by soluble factors in conditioned hepatic cell medium. With that approach, we want to mimic in vitro the situation of preclinical transplantation experiments using human cells in mice. Cord blood stem cells, cultivated with hepatic conditioned medium, showed a low endodermal differentiation but an increased connexin 32 (Cx32) and Cx43, and cytokeratin 8 (CK8) and CK19 expression was monitored by reverse transcription polymerase chain reaction (RT-PCR). Microarray profiling indicated that in cultivated cord blood cells, 604 genes were upregulated 2-fold, with the highest expression for epithelial CK19 and epithelial cadherin (E-cadherin). On ultrastructural level, there were no major changes in the cellular morphology, except a higher presence of phago(ly)some-like structures observed. Direct co-culture of AML12 cells with cord blood cells led to less incisive differentiation with increased sex-determining region Y-box 17 (SOX17), Cx32 and Cx43, as well as epithelial CK8 and CK19 expressions. On ultrastructural level, tight cell contacts along the plasma membranes were revealed. FACS analysis in co-cultivated cells quantified dye exchange on low level, as also proved by time relapse video-imaging of labelled cells. Modulators of gap junction formation influenced dye transfer between the co-cultured cells, whereby retinoic acid increased and 3-heptanol reduced the dye transfer. The study indicated that the cell-co-cultured model of human umbilical cord blood cells and murine AML12 cells may be a suitable approach to study some aspects of endodermal/hepatic cell differentiation induction.

Early gestation chorionic villi-derived stromal cells for fetal tissue engineering

AIM

To investigate the potential for early gestation placenta-derived mesenchymal stromal cells (PMSCs) for fetal tissue engineering.

METHODS

PMSCs were isolated from early gestation chorionic villus tissue by explant culture. Chorionic villus sampling (CVS)-size tissue samples (mean = 35.93 mg) were used to test the feasibility of obtaining large cell numbers from CVS within a clinically relevant timeframe. We characterized PMSCs isolated from 6 donor placentas by flow cytometry immunophenotyping, multipotency assays, and through immunofluorescent staining. Protein secretion from PMSCs was examined using two cytokine array assays capable of probing for over 70 factors in total. Delivery vehicle compatibility of PMSCs was determined using three common scaffold systems: fibrin glue, collagen hydrogel, and biodegradable nanofibrous scaffolds made from a combination of polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). Viral transduction of PMSCs was performed using a Luciferase-GFP-containing lentiviral vector and efficiency of transduction was tested by fluorescent microscopy and flow cytometry analysis.

RESULTS

We determined that an average of 2.09 × 10(6) (SD ± 8.59 × 10(5)) PMSCs could be obtained from CVS-size tissue samples within 30 d (mean = 27 d, SD ± 2.28), indicating that therapeutic numbers of cells can be rapidly expanded from very limited masses of tissue. Immunophenotyping by flow cytometry demonstrated that PMSCs were positive for MSC markers CD105, CD90, CD73, CD44, and CD29, and were negative for hematopoietic and endothelial markers CD45, CD34, and CD31. PMSCs displayed trilineage differentiation capability, and were found to express developmental transcription factors Sox10 and Sox17 as well as neural-related structural proteins NFM, Nestin, and S100β. Cytokine arrays revealed a robust and extensive profile of PMSC-secreted cytokines and growth factors, and detected 34 factors with spot density values exceeding 10(3). Detected factors had widely diverse functions that include modulation of angiogenesis and immune response, cell chemotaxis, cell proliferation, blood vessel maturation and homeostasis, modulation of insulin-like growth factor activity, neuroprotection, extracellular matrix degradation and even blood coagulation. Importantly, PMSCs were also determined to be compatible with both biological and synthetic material-based delivery vehicles such as collagen and fibrin hydrogels, and biodegradable nanofiber scaffolds made from a combination of PLA and PLGA. Finally, we demonstrated that PMSCs can be efficiently transduced (> 95%) with a Luciferase-GFP-containing lentiviral vector for future in vivo cell tracking after transplantation.

CONCLUSION

Our findings indicate that PMSCs represent a unique source of cells that can be effectively utilized for in utero cell therapy and tissue engineering.

Autologous bone marrow-derived cells in the treatment of liver disease patients

Liver transplantation is universally accepted as a "cure" procedure, and yet is not universally applicable for the treatment of end-stage liver diseases (ESLD) because of the shortage of donors, operative complications, risk of rejection, and high cost. Bioartificial liver device is an option to temporarily improve the liver function and to bridge the patients to liver transplantation. However, bioartificial liver device has many problems in clinical application, such as hepatocyte allograft rejection and maintenance of hepatocyte viability and function. Another therapeutic option is stem cell transplantation. There are two broad types of stem cells: Embryonic stem cells and adult stem cells. The latter are sourced from bone marrow (BM), adipose tissue, and blood. This review will concentrate on BM-derived cells. BM-derived cell transplantation, although not ideal, is theoretically an optimal modality for the treatment of ESLD. Autologous BM-derived cells have no graft rejection, have the capability of regeneration and self-renewal, and are multipotent stem cells that can differentiate into a variety of cell types which include hepatocytes. The pathway from BM-derived cell to hepatocyte is well documented. The present review summarizes the delivery routes of BM-derived cells to the liver, the evidences of engraftment of BM-derived cells in the liver, and the possible mechanisms of BM-derived cells in liver repair and regeneration, and finally, updates the clinical applications.

Mesenchymal stem cells promote liver regeneration and prolong survival in small-for-size liver grafts: involvement of C-Jun N-terminal kinase, cyclin D1, and NF-κB

Background

The therapeutic potential of mesenchymal stem cells (MSCs) has been highlighted recently for treatment of acute or chronic liver injury, by possibly differentiating into hepatocyte-like cells, reducing inflammation, and enhancing tissue repair. Despite recent progress, exact mechanisms of action are not clearly elucidated. In this study, we attempted to explore whether and how MSCs protected hepatocytes and stimulated allograft regeneration in small-for-size liver transplantation (SFSLT).

Methods

SFSLT model was established with a 30% partial liver transplantation (30PLT) in rats. The differentiation potential and characteristics of bone marrow derived MSCs were explored in vitro. MSCs were infused transvenously immediately after graft implantation in therapy group. Expressions of apoptosis-, inflammatory-, anti-inflammatory-, and growth factor-related genes were measured by RT-PCR, activities of transcription factors AP-1 and NF-κB were analyzed by EMSA, and proliferative responses of the hepatic graft were evaluated by immunohistochemistry and western blot.

Results

MSCs were successfully induced into hepatocyte-like cells, osteoblasts and adipocytes in vitro. MSCs therapy could not only alleviate ischemia reperfusion injury and acute inflammation to promote liver regeneration, but also profoundly improve one week survival rate. It markedly up-regulated the mRNA expressions of HGF, Bcl-2, Bcl-XL, IL-6, IL-10, IP-10, and CXCR2, however, down-regulated TNF-α. Increased activities of AP-1 and NF-κB, as well as elevated expressions of p-c-Jun, cyclin D1, and proliferating cell nuclear antigen (PCNA), were also found in MSCs therapy group.

Conclusion

These data suggest that MSCs therapy promotes hepatocyte proliferation and prolongs survival in SFSLT by reducing ischemia reperfusion injury and acute inflammation, and sustaining early increased expressions of c-Jun N-terminal Kinase, Cyclin D1, and NF-κB.

Liver cell therapy and tissue engineering for transplantation

Liver transplantation remains the only definitive treatment for liver failure and is available to only a tiny fraction of patients with end-stage liver diseases. Major limitations for the procedure include donor organ shortage, high cost, high level of required expertise, and long-term consequences of immune suppression. Alternative cell-based liver therapies could potentially greatly expand the number of patients provided with effective treatment. Investigative research into augmenting or replacing liver function extends into three general strategies. Bioartificial livers (BALs) are extracorporeal devices that utilize cartridges of primary hepatocytes or cell lines to process patient plasma. Injection of liver cell suspensions aims to foster organ regeneration or provide a missing metabolic function arising from a genetic defect. Tissue engineering recreates the organ in vitro for subsequent implantation to augment or replace patient liver function. Translational models and clinical trials have highlighted both the immense challenges involved and some striking examples of success.