The phenotypic characteristic of liver-derived stem cells from adult human deceased donor liver

Potential Effect of DPP-4 Inhibitors Towards Hepatic Diseases and Associated Glucose Intolerance

Dipeptidyl-peptidase-4 (DPP-4) is an enzyme having various properties and physiological roles in lipid accumulation, resistance to anticancer agents, and immune stimulation. DPP-4 includes membrane-bound peptidases and is a kind of enzyme that cleaves alanine or proline-containing peptides such as incretins, chemokines, and appetite-suppressing hormones (neuropeptide) at their N-terminal dipeptides. DPP-4 plays a role in the final breakdown of peptides produced by other endo and exo-peptidases from nutritious proteins and their absorption in these tissues. DPP-4 enzyme activity has different modes of action on glucose metabolism, hunger regulation, gastrointestinal motility, immune system function, inflammation, and pain regulation. According to the literature survey, as DPP-4 levels increase in individuals with liver conditions, up-regulation of hepatic DPP-4 expression is likely to be the cause of glucose intolerance or insulin resistance. This review majorly focuses on the cleavage of alanine or proline-containing peptides such as incretins by the DPP-4 and its resulting conditions like glucose intolerance and cause of DPP-4 level elevation due to some liver conditions. Thus, we have discussed the various effects of DPP-4 on the liver diseases like hepatitis C, non-alcoholic fatty liver, hepatic regeneration and stem cell, hepatocellular carcinoma, and the impact of elevated DPP-4 levels in association with liver diseases as a cause of glucose intolerance and their treatment drug of choices. In addition, the effect of DPP-4 inhibitors on obesity and their negative aspects are also discussed in brief.

Human Liver Stem Cell Transplantation Alleviates Liver Fibrosis in a Rat Model of CCl4-Induced Liver Fibrosis

Background and Objectives

Mesenchymal stem cells (MSCs) elicit therapeutic effects against liver fibrosis in animal models. Human liver stem cells (HLSCs) are cells isolated from human liver tissue that have mesenchymal morphology and express MSC markers. HLSCs also possess intrahepatic stem cell properties. We introduce a rat model of liver fibrosis and trans-portal transplantation of HLSC to demonstrate alleviation of liver fibrosis.

Methods and Results

Liver fibrosis was induced by intraperitoneal injection of Carbon tetrachloride (CCl₄). Sprague Dawley rats underwent simultaneous partial hepatectomy of the left hepatic lobe and HLSC transplantation via the portal vein. Gross appearance of the liver observed following CCl₄ injection showed cholestasis and surface nodularity. Sirius red staining revealed deposition of collagen fibers in the extracellular matrix (ECM). Following HLSC transplantation, human albumin secreting cells were detected by immunohistochemistry in liver specimens. Quantitative measurements of fibrosis area stained by Sirius red were compared between baseline and post-HLSC transplant (1×10⁷ cells) following 10 weeks of CCl₄ treatment liver specimens. Fibrosis area (p<0.05), serum markers of liver inflammation and fibrosis (AST, ALT levels and APRI, p<0.05) significantly decreased from baseline after HLSC transplantation. RNA expression in liver tissues revealed significant decrease in tissue inhibitor of matrix metalloproteinase 1 (TIMP1), TIMP2 expression and increase in hepatocyte growth factor expression following HLSC transplantation (p<0.05).

Conclusions

HLSC transplantation effectively reduced the area of liver fibrosis with increased expression of factors promoting ECM degradation. These findings suggest the potential therapeutic role of HLSCs in various liver diseases presenting with liver fibrosis.

Characterizing Organelles in Live Stem Cells Using Label-Free Optical Diffraction Tomography

Label-free optical diffraction tomography (ODT), an imaging technology that does not require fluorescent labeling or other pre-processing, can overcome the limitations of conventional cell imaging technologies, such as fluorescence and electron microscopy. In this study, we used ODT to characterize the cellular organelles of three different stem cells-namely, human liver derived stem cell, human umbilical cord matrix derived mesenchymal stem cell, and human induced pluripotent stem cell-based on their refractive index and volume of organelles. The physical property of each stem cell was compared with that of fibroblast. Based on our findings, the characteristic physical properties of specific stem cells can be quantitatively distinguished based on their refractive index and volume of cellular organelles. Altogether, the method employed herein could aid in the distinction of living stem cells from normal cells without the use of fluorescence or specific biomarkers.

Human Liver Stem Cells: A Liver-Derived Mesenchymal Stromal Cell-Like Population With Pro-regenerative Properties

Human liver stem cells (HLSCs) were described for the first time in 2006 as a new stem cell population derived from healthy human livers. Like mesenchymal stromal cells, HLSCs exhibit multipotent and immunomodulatory properties. HLSCs can differentiate into several lineages under defined in vitro conditions, such as mature hepatocytes, osteocytes, endothelial cells, and islet-like cell organoids. Over the years, HLSCs have been shown to contribute to tissue repair and regeneration in different in vivo models, leading to more than five granted patents and over 15 peer reviewed scientific articles elucidating their potential therapeutic role in various experimental pathologies. In addition, HLSCs have recently completed a Phase 1 study evaluating their safety post intrahepatic injection in infants with inherited neonatal onset hyperammonemia. Even though a lot of progress has been made in understanding HLSCs over the past years, some important questions regarding the mechanisms of action remain to be elucidated. Among the mechanisms of interaction of HLSCs with their environment, a paracrine interface has emerged involving extracellular vesicles (EVs) as vehicles for transferring active biological materials. In our group, the EVs derived from HLSCs have been studied in vitro as well as in vivo. Our attention has mainly been focused on understanding the in vivo ability of HLSC–derived EVs as modulators of tissue regeneration, inflammation, fibrosis, and tumor growth. This review article aims to discuss in detail the role of HLSCs and HLSC-EVs in these processes and their possible future therapeutic applications.

The Potential Safe Antifibrotic Effect of Stem Cell Conditioned Medium and Nilotinib Combined Therapy by Selective Elimination of Rat Activated HSCs

Hepatic fibrosis is a progressive disease with serious clinical complications that arise from abnormal propagation and activation of multiple inflammatory pathways. Nilotinib is an oral tyrosine kinase inhibitor with antifibrotic activity. Mesenchymal stem cells (MSCs) are blank cells and can differentiate into specific cell types. They have the potential to repair and regenerate cells. MSCs have a special paracrine fashion where they produce special exosomes, microvesicles, and cytokines like IL-6, transforming growth factor-beta (TGF-β), and HGF as well as hepatic stellate cell suppressors. This paracrine fashion can decrease collagen deposition, enhance antifibrotic, anti-inflammatory, and angiogenic activity in vitro and in vivo. In our study, the rat's hepatic stellate cells (HSCs) in addition to different normal cell lines were treated with Nilotinib alone and in combination with liver mesenchymal stem cells conditioned medium (LMSCs-CM) for 24 h. Mono and combined therapy antifibrotic and cytotoxicity effects were evaluated using different parameters including α-SMA, cytochrome c, P53 expression, collagen deposition, DNA content, oxidative stress parameters, cell viability, and apoptosis by flow cytometry analysis. Our results showed that Nilotinib and LMSCs-CM in combination had a significantly potent antifibrotic and anti-inflammatory effect on activated hepatic stellate cells than Nilotinib alone; otherwise, this combination showed the best safety with minimal cytotoxicity on different normal cell lines.

Cell Sources and Influencing Factors of Liver Regeneration: A Review

Liver regeneration (LR) is a set of complicated mechanisms between cells and molecules in which the processes of initiation, maintenance, and termination of liver repair are regulated. Although LR has been studied extensively, there are still numerous challenges in gaining its full understanding. Cells for LR have a wide range of sources and the feature of plasticity, and regeneration patterns are not the same under different conditions. Many patients undergoing partial hepatectomy develop cirrhosis or steatosis. The changes of LR in these cases are not clear. Many types of cells participate in LR. Hepatocytes, biliary epithelial cells, hepatic progenitor cells, and human liver stem cells can serve as the cell sources for LR. However, different types and degrees of damage trigger the response from the most suitable cells. Exploring the cell sources of LR is of great significance for accelerating recovery of liver function under different pathological patterns and developing a cell therapy strategy to cope with the shortage of donors for liver transplantation. In clinical practice, the background of the liver influences regeneration. Fibrosis and steatosis create different LR microenvironments and signal molecule interaction patterns. In addition, factors such as partial hepatectomy, aging, platelets, nerves, hormones, bile acids, and gut microbiota are widely involved in this process. Understanding the influencing factors of LR has practical value for individualized treatment of patients with liver diseases. In this review, we have summarized recent studies and proposed our views. We discuss cell sources and the influential factors on LR to help in solving clinical problems.

Differentiation of Cells Isolated from Afterbirth Tissues into Hepatocyte-Like Cells and Their Potential Clinical Application in Liver Regeneration

Toxic, viral and surgical injuries can pose medical indications for liver transplantation. The number of patients waiting for a liver transplant still increases, but the number of organ donors is insufficient. Hepatocyte transplantation was suggested as a promising alternative to liver transplantation, however, this method has some significant limitations. Currently, afterbirth tissues seem to be an interesting source of cells for the regenerative medicine, because of their unique biological and immunological properties. It has been proven in experimental animal models, that the native stem cells, and to a greater extent, hepatocyte-like cells derived from them and transplanted, can accelerate regenerative processes and restore organ functioning. The effective protocol for obtaining functional mature hepatocytes in vitro is still not defined, but some studies resulted in obtaining functionally active hepatocyte-like cells. In this review, we focused on human stem cells isolated from placenta and umbilical cord, as potent precursors of hepatocyte-like cells for regenerative medicine. We summarized the results of preclinical and clinical studies dealing with the introduction of epithelial and mesenchymal stem cells of the afterbirth origin to the liver failure therapy. It was concluded that the use of native afterbirth epithelial and mesenchymal cells in the treatment of liver failure could support liver function and regeneration. This effect would be enhanced by the use of hepatocyte-like cells obtained from placental and/or umbilical stem cells.

Hepatogenic Potential and Liver Regeneration Effect of Human Liver-derived Mesenchymal-Like Stem Cells

Human liver-derived stem cells (hLD-SCs) have been proposed as a possible resource for stem cell therapy in patients with irreversible liver diseases. However, it is not known whether liver resident hLD-SCs can differentiate toward a hepatic fate better than mesenchymal stem cells (MSCs) obtained from other origins. In this study, we compared the differentiation ability and regeneration potency of hLD-SCs with those of human umbilical cord matrix-derived stem cells (hUC-MSCs) by inducing hepatic differentiation. Undifferentiated hLD-SCs expressed relatively high levels of endoderm-related markers (GATA4 and FOXA1). During directed hepatic differentiation supported by two small molecules (Fasudil and 5-azacytidine), hLD-SCs presented more advanced mitochondrial respiration compared to hUC-MSCs. Moreover, hLD-SCs featured higher numbers of hepatic progenitor cell markers on day 14 of differentiation (CPM and CD133) and matured into hepatocyte-like cells by day 7 through 21 with increased hepatocyte markers (ALB, HNF4A, and AFP). During in vivo cell transplantation, hLD-SCs migrated into the liver of ischemia-reperfusion injury-induced mice within 2 h and relieved liver injury. In the thioacetamide (TAA)-induced liver injury mouse model, transplanted hLD-SCs trafficked into the liver and spontaneously matured into hepatocyte-like cells within 14 days. These results collectively suggest that hLD-SCs hold greater hepatogenic potential, and hepatic differentiation-induced hLD-SCs may be a promising source of stem cells for liver regeneration.

Pluripotent-Stem-Cell-Derived Hepatic Cells: Hepatocytes and Organoids for Liver Therapy and Regeneration

The liver is a very complex organ that ensures numerous functions; it is thus susceptible to multiple types of damage and dysfunction. Since 1983, orthotopic liver transplantation (OLT) has been considered the only medical solution available to patients when most of their liver function is lost. Unfortunately, the number of patients waiting for OLT is worryingly increasing, and extracorporeal liver support devices are not yet able to counteract the problem. In this review, the current and expected methodologies in liver regeneration are briefly analyzed. In particular, human pluripotent stem cells (hPSCs) as a source of hepatic cells for liver therapy and regeneration are discussed. Principles of hPSC differentiation into hepatocytes are explored, along with the current limitations that have led to the development of 3D culture systems and organoid production. Expected applications of these organoids are discussed with particular attention paid to bio artificial liver (BAL) devices and liver bio-fabrication.

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

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

Current Understanding of Stem Cell and Secretome Therapies in Liver Diseases

Liver failure is one of the main risks of death worldwide, and it originates from repetitive injuries and inflammations of liver tissues, which finally leads to the liver cirrhosis or cancer. Currently, liver transplantation is the only effective treatment for the liver diseases although it has a limitation due to donor scarcity. Alternatively, cell therapy to regenerate and reconstruct the damaged liver has been suggested to overcome the current limitation of liver disease cures. Several transplantable cell types could be utilized for recovering liver functions in injured liver, including bone marrow cells, mesenchymal stem cells, hematopoietic stem cells, macrophages, and stem cell-derived hepatocytes. Furthermore, paracrine effects of transplanted cells have been suggested as a new paradigm for liver disease cures, and this application would be a new strategy to cure liver failures. Therefore, here we reviewed the current status and challenges of therapy using stem cells for liver disease treatments.

Liver-derived human mesenchymal stem cells: a novel therapeutic source for liver diseases

Mesenchymal stem cells (MSCs) represent an attractive cell type for research and therapy due to their ability to proliferate, differentiate, modulate immune reactions, and secrete trophic factors. MSCs exist in a multitude of tissues, including bone marrow, umbilical cord, and adipose tissues. Moreover, MSCs have recently been isolated from the liver. Compared with other MSC types, liver-derived human MSCs (LHMSCs) possess general morphologies, immune functions, and differentiation capacities. Interestingly, LHMCSs produce higher levels of pro-angiogenic, anti-inflammatory, and anti-apoptotic cytokines than those of bone marrow-derived MSCs. Thus, these cells may be a promising therapeutic source for liver diseases. This paper summarizes the biological characteristics of LHMSCs and their potential benefits and risks for the treatment of liver diseases.

Suppression of T-cell proliferation by and B7-H1 expression on human liver-derived stem cells

BACKGROUND

Many types of stem cells have been widely used for the treatment of liver diseases. The therapeutic effect of stem cells is predominantly based on the immune regulatory properties of these cells.

METHODS

We isolated human liver stem cells (HLSCs), which are considered intrahepatic stem cells, and examined their suppression of T-cell proliferation induced by phytohemagglutinin.

RESULTS

HLSCs inhibited phytohemagglutinin-induced T-cell proliferation not only in direct co-culture but also in indirect co-culture in a cell number-dependent manner. That is, T-cell proliferation was substantially inhibited by cell-to-cell contact regardless of soluble factor(s). B7-H1, a co-inhibitory molecule that relies on cell-to-cell contact, was found to be constitutively expressed at low levels on HLSCs. Furthermore, its expression was upregulated moderately by tumor necrosis factor-α and dramatically by interferon-γ.

CONCLUSIONS

These results suggest that HLSCs would have therapeutic effects through T-cell suppression in acute liver diseases.

In vitro differentiation of human liver-derived stem cells with mesenchymal characteristics into immature hepatocyte-like cells. Transplant Proc. 2014;46:1633-1637. [PMID: 24935339 DOI: 10.1016/j.transproceed.2013.12.070]

Liver transplantation is severely limited by donor shortage although it is the only effective treatment for end-stage liver disease. So the best alternative is hepatocyte transplantation. For obtaining human hepatocytes, some stem cells originating from extrahepatic or intraheptic tissues have been isolated and characterized. Previously we have reported that human liver-derived stem cells (HLSCs) could be isolated and expanded from donated livers unsuitable for transplantation; they expressed some markers of mesenchymal stem cells but neither hematopoietic nor oval cells. In this study, we isolated and expanded HLSCs with mesenchymal characteristics from another adult human liver. They showed mesenchymal morphology and grew well under serum condition similar to our previous reports. Also, they expressed some markers of mesenchymal stem cells, such as CD44, CD73, CD90, and CD105, through fluorescence-activated cell sorting analysis. When HLSCs were sequentially exposed to fibroblast growth factor-1 (FGF-1), FGF-4, and hepatocyte growth factor (HGF) followed by FGF-4, HGF, oncostatin M, and dexamethasone, they became round or polygonal, and expressed some hepatic markers such as albumin and α1-antitrypsin in the gene or protein level. Also, they showed urea synthesis activity 7 days after treatment of FGF-4, HGF, oncostatin M, and dexamethasone. These results provided that HLSCs would be a useful cell source in the field of regenerative medicine as well as liver cell biology.

Nestin involvement in tissue injury and cancer--a potential tumor marker?

BACKGROUND

In eukaryotic cells, the cytoskeleton contains three major filamentous components: actin microfilaments, microtubules and intermediate filaments. Nestin represents one of the class VI intermediate filament proteins. Clinical and molecular analyses have revealed substantial information regarding the presence of Nestin in cells with progenitor or stem cell properties. During tissue injury Nestin is expressed in cells with progenitor cell-like properties. These cells may serve as a tissue reserve and, as such, may contribute to tissue repair. Based on currently available data, Nestin also appears to be implicated in two oncogenic processes. First, Nestin has been found to be expressed in cancer stem-like cells and poorly differentiated cancer cells and, as such, Nestin is thought to contribute to the aggressive behavior of these cells. Second, Nestin has been found to be involved in tumor angiogenesis through an interaction of cancer cells and blood vessel endothelial cells and, as such, Nestin is thought to facilitate tumor growth.

CONCLUSIONS

We conclude that Nestin may serve as a promising tumor marker and as a potential therapeutic target amenable to tumor suppression and angiogenesis inhibition.

Cross-linked iron oxide nanoparticles for therapeutic engineering and in vivo monitoring of mesenchymal stem cells in cerebral ischemia model

Poly(ethylene glycol)-coated cross-linked iron oxide nanoparticles (PCIONs) are developed for therapeutic engineering of mesenchymal stem cells (MSCs) and their monitoring via magnetic resonance (MR) imaging at a time. PCIONs successfully combine with plasmid DNA (pDNA) via ionic interaction. Accordingly, PCION/pDNA complexes mediate superior translocations of vascular endothelial growth factor (VEGF) pDNA into intracellular regions of MSCs under external magnetic field, which significantly elevate production of VEGF from MSCs. Genetically engineered MSCs are also clearly visualized via MR imaging after administration to rat cerebrovascular ischemia models, which enable tracking of MSCs migration from injected sites to injured ischemic area.

Dipeptidyl peptidase-4: A key player in chronic liver disease

Dipeptidyl peptidase-4 (DPP-4) is a membrane-associated peptidase, also known as CD26. DPP-4 has widespread organ distribution throughout the body and exerts pleiotropic effects via its peptidase activity. A representative target peptide is glucagon-like peptide-1, and inactivation of glucagon-like peptide-1 results in the development of glucose intolerance/diabetes mellitus and hepatic steatosis. In addition to its peptidase activity, DPP-4 is known to be associated with immune stimulation, binding to and degradation of extracellular matrix, resistance to anti-cancer agents, and lipid accumulation. The liver expresses DPP-4 to a high degree, and recent accumulating data suggest that DPP-4 is involved in the development of various chronic liver diseases such as hepatitis C virus infection, non-alcoholic fatty liver disease, and hepatocellular carcinoma. Furthermore, DPP-4 occurs in hepatic stem cells and plays a crucial role in hepatic regeneration. In this review, we described the tissue distribution and various biological effects of DPP-4. Then, we discussed the impact of DPP-4 in chronic liver disease and the possible therapeutic effects of a DPP-4 inhibitor.