The liver has a complex cellular composition and a remarkable regenerative capacity. The primary cell types in the liver are two parenchymal cell populations, hepatocytes and cholangiocytes, that perform most of the functions of the liver and that are helped through interactions with non-parenchymal cell types comprising stellate cells, endothelia and various hemopoietic cell populations. The regulation of the cells in the liver is mediated by an insoluble complex of proteins and carbohydrates, the extracellular matrix, working synergistically with soluble paracrine and systemic signals. In recent years, with the rapid development of genetic sequencing technologies, research on the liver's cellular composition and its regulatory mechanisms during various conditions has been extensively explored. Meanwhile breakthroughs in strategies for cell transplantation are enabling a future in which there can be a rescue of patients with end-stage liver diseases, offering potential solutions to the chronic shortage of livers and alternatives to liver transplantation. This review will focus on the cellular mechanisms of liver homeostasis and how to select ideal sources of cells to be transplanted to achieve liver regeneration and repair. Recent advances are summarized for promoting the treatment of end-stage liver diseases by forms of cell transplantation that now include grafting strategies.
Humans ; Liver/surgery* ; Hepatocytes/transplantation* ; Stem Cells/metabolism* ; Liver Diseases/surgery*

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of autosomal recessive liver diseases that present as neonatal cholestasis. Little is known of this disease in Korea. METHODS: The records of five patients histologically diagnosed with PFIC, one with PFIC1 and four with PFIC2, by liver biopsy or transplant were reviewed, and ATP8B1 and ABCB11 mutation status was analyzed by direct DNA sequencing. Clinicopathological characteristics were correlated with genetic mutations. RESULTS: The first symptom in all patients was jaundice. Histologically, lobular cholestasis with bile plugs was the main finding in all patients, whereas diffuse or periportal cholestasis was identified only in patients with PFIC2. Giant cells and ballooning of hepatocytes were observed in three and three patients with PFIC2, respectively, but not in the patient with PFIC1. Immunostaining showed total loss of bile salt export pump in two patients with PFIC2 and focal loss in two. Lobular and portal based fibrosis were more advanced in PFIC2 than in PFIC1. ATP8B1 and ABCB11 mutations were identified in one PFIC1 and two PFIC2 patients, respectively. One PFIC1 and three PFIC2 patients underwent liver transplantation (LT). At age 7 months, one PFIC2 patient was diagnosed with concurrent hepatocellular carcinoma and infantile hemangioma in an explanted liver. The patient with PFIC1 developed steatohepatitis after LT. One patient showed recurrence of PFIC2 after 10 years and underwent LT. CONCLUSIONS: PFIC is not rare in patients with neonatal cholestasis of unknown origin. Proper clinicopathologic correlation and genetic testing can enable early detection and management.
Bile ; Biopsy ; Carcinoma, Hepatocellular ; Cholestasis ; Cholestasis, Intrahepatic ; Fatty Liver ; Fibrosis ; Genetic Testing ; Giant Cells ; Hemangioma ; Hepatocytes ; Humans ; Jaundice ; Korea ; Liver ; Liver Diseases ; Liver Transplantation ; Recurrence ; Sequence Analysis, DNA

BACKGROUND: Liver disease is one of the top causes of death globally. Although liver transplantation is a very effective treatment strategy, the shortage of available donor organs, waiting list mortality, and high costs of surgery remain huge problems. Stem cells are undifferentiated cells that can differentiate into a variety of cell types. Scientists are exploring the possibilities of generating hepatocytes from stem cells as an alternative for the treatment of liver diseases. METHODS: In this review, we summarized the updated researches in the field of stem cell-based therapies for liver diseases as well as the current challenges and future expectations for a successful cell-based liver therapy. RESULTS: Several cell types have been investigated for liver regeneration, such as embryonic stem cells, induced pluripotent stem cells, liver stem cells, mesenchymal stem cells, and hematopoietic stem cells. In vitro and in vivo studies have demonstrated that stem cells are promising cell sources for the liver regeneration. CONCLUSION: Stem cell-based therapy could be a promising therapeutic method for patients with end-stage liver disease, which may alleviate the need for liver transplantation in the future.
Cause of Death ; Embryonic Stem Cells ; Hematopoietic Stem Cells ; Hepatocytes ; Humans ; In Vitro Techniques ; Induced Pluripotent Stem Cells ; Liver Diseases ; Liver Regeneration ; Liver Transplantation ; Liver ; Mesenchymal Stromal Cells ; Methods ; Mortality ; Stem Cells ; Tissue Donors ; Waiting Lists

Acute fatty liver of pregnancy (AFLP) is unusual but can potentially progress to overwhelming liver failure, resulting in maternal and fetal death. AFLP is characterized by the accumulation of microvesicular fat within hepatocytes. We report the case of a 37-year-old woman at 36 weeks' gestation with a twin pregnancy who was admitted with the diagnosis of intrauterine fetal death of one baby. The patient showed profile of AFLP on her laboratory findings and underwent emergency cesarean section. Then she progressed to cryptogenic fulminant hepatic failure and underwent successful orthotopic liver transplantation on 9th day of admission. This case demonstrates that liver transplantation is a feasible therapeutic option for the treatment of patients with this condition.
Adult ; Anesthesia, General ; Cesarean Section ; Diagnosis ; Emergencies ; Fatty Liver ; Female ; Fetal Death ; Hepatocytes ; Humans ; Liver Failure ; Liver Failure, Acute ; Liver Transplantation ; Liver ; Pregnancy ; Pregnancy, Twin

PURPOSE: Multidrug resistance-associated protein (MRP) 2 is a glutathione conjugate in the canalicular membrane of hepatocytes. Early graft damage after liver transplantation (LT) can result in alteration of MRP2 expression. The purpose of this study was to evaluate the relationship between the pattern of MRP2 alteration and graft outcome. METHODS: Forty-one paraffin-embedded liver graft tissues obtained by protocol biopsy within 2 months after LT; these were stained using monoclonal antibodies of MRP2. We selected 15 live donor biopsy samples as a control, that showed homogenous canalicular staining for MRP2. The pattern of canalicular MRP2 staining of graft was classified into 3 types: homogenous (type C0), focal (type C1), and no (type C2,) staining of the canaliculi. RESULTS: In total, 17.1% graft tissues were type C0, 36.6% were type C1, and 46.3% were type C2. The median operation time was longer in patients with type C2 (562.6 minutes) than in patients with type C0 (393.8 minutes) (P = 0.038). The rates of posttransplant complications were higher in patients with type C2 (100%) than in patients with type C0 (42.9%) and C1 (73.3%) (P < 0.001). CONCLUSION: MRP2 expression pattern was altered in 82.9% after LT. The pattern of MRP2 alteration was associated with longer operation time and higher rates of post-LT complications.
Antibodies, Monoclonal ; Biopsy ; Glutathione ; Hepatocytes ; Humans ; Liver Transplantation* ; Liver* ; Membranes ; Multidrug Resistance-Associated Proteins ; Tissue Donors ; Transplants*

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.
Bone Marrow Cells ; Cell- and Tissue-Based Therapy ; Hematopoietic Stem Cells ; Hepatocytes ; Humans ; Inflammation ; Liver Cirrhosis ; Liver Diseases* ; Liver Failure ; Liver Regeneration ; Liver Transplantation ; Liver* ; Macrophages ; Mesenchymal Stromal Cells ; Stem Cell Transplantation ; Stem Cells* ; Tissue Donors

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

The liver is the largest organ in the body; it has a complex architecture, wide range of functions and unique regenerative capacity. The growing incidence of liver diseases worldwide requires increased numbers of liver transplant and leads to an ongoing shortage of donor livers. To meet the huge demand, various alternative approaches are being investigated including, hepatic cell transplantation, artificial devices and bioprinting of the organ itself. Adult hepatocytes are the preferred cell sources, but they have limited availability, are difficult to isolate, propagate poor and undergo rapid functional deterioration in vitro. There have been efforts to overcome these drawbacks; by improving culture condition for hepatocytes, providing adequate extracellular matrix, co-culturing with extra-parenchymal cells and identifying other cell sources. Differentiation of human stem cells to hepatocytes has become a major interest in the field of stem cell research and has progressed greatly. At the same time, use of decellularized organ matrices and 3 D printing are emerging cutting-edge technologies for tissue engineering, opening up new paths for liver regenerative medicine. This review provides a compact summary of the issues, and the locations of liver support systems and tissue engineering, with an emphasis on reproducible and useful sources of hepatocytes including various candidates formed by differentiation from stem cells.
Adult ; Bioprinting ; Extracellular Matrix ; Hepatocytes ; Humans ; Incidence ; Liver Diseases ; Liver Transplantation* ; Liver* ; Liver, Artificial ; Regenerative Medicine ; Stem Cell Research ; Stem Cells ; Tissue Donors ; Tissue Engineering*

Currently, the most effective treatment for end-stage liver fibrosis is liver transplantation; however, transplantation is limited by a shortage of donor organs, surgical complications, immunological rejection, and high medical costs. Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have the potential to differentiate into hepatocytes, and therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. In addition, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis and enhance liver functionality. Despite these advantages, issues remain; MSCs also have fibrogenic potential and the capacity to promote tumor cell growth and oncogenicity. This paper summarizes the properties of MSCs for regenerative medicine and their therapeutic mechanisms and clinical application in the treatment of liver fibrosis. We also present several outstanding risks, including their fibrogenic potential and their capacity to promote pre-existing tumor cell growth and oncogenicity.
Animals ; Cell Differentiation ; Cell Proliferation ; Hepatocytes/immunology/metabolism/pathology/*transplantation ; Humans ; Liver/immunology/metabolism/pathology/physiopathology/*surgery ; Liver Cirrhosis/diagnosis/immunology/metabolism/physiopathology/*surgery ; Liver Regeneration ; *Mesenchymal Stem Cell Transplantation/adverse effects ; *Mesenchymal Stromal Cells/immunology/metabolism/pathology ; Phenotype ; Regenerative Medicine/*methods ; Risk Factors ; Signal Transduction ; Treatment Outcome

The transplantation of mesenchymal stem cells (MSCs) represents a potentially effective therapy for chronic liver diseases. The potential of MSCs in the treatment of chronic liver disease is based on their ability to differentiate into multiple cell types including hepatocytes, their immunosuppressive properties, and their ability to secrete various trophic factors. This potential has been investigated in clinical and pre-clinical studies. Although the therapeutic mechanisms of MSC transplantation are still not fully characterized, accumulating evidence has revealed that various trophic factors secreted by MSCs play key therapeutic roles in regeneration. These trophic factors not only reduce inflammation, apoptosis, and fibrosis in damaged tissues but also stimulate angiogenesis and tissue regeneration in the impaired liver. In this review, we summarize the basic and therapeutic properties of MSCs, their therapeutic mechanisms of action, and potential transplantation routes for the treatment of chronic liver disease. We also discuss several risks associated with the use of MSCs in therapy, such as their fibrogenic potential and capacity to promote pre-existing tumor cell growth.
Adult Stem Cells* ; Adult* ; Apoptosis ; Cell Transplantation ; End Stage Liver Disease ; Fibrosis ; Hepatocytes ; Humans ; Inflammation ; Liver Diseases* ; Liver Regeneration ; Liver* ; Mesenchymal Stromal Cells ; Regeneration