Stem cells are attracting attention as a key element in future medicine, satisfying the desire to live a healthier life with the possibility that they can regenerate tissue damaged or degenerated by disease or aging. Stem cells are defined as undifferentiated cells that have the ability to replicate and differentiate themselves into various tissues cells. Stem cells, commonly encountered in clinical or preclinical stages, are largely classified into embryonic, adult, and induced pluripotent stem cells. Recently, stem cell transplantation has been frequently applied to the treatment of pain as an alternative or promising approach for the treatment of severe osteoarthritis, neuropathic pain, and intractable musculoskeletal pain which do not respond to conventional medicine. The main idea of applying stem cells to neuropathic pain is based on the ability of stem cells to release neurotrophic factors, along with providing a cellular source for replacing the injured neural cells, making them ideal candidates for modulating and possibly reversing intractable neuropathic pain. Even though various differentiation capacities of stem cells are reported, there is not enough knowledge and technique to control the differentiation into desired tissues in vivo. Even though the use of stem cells is still in the very early stages of clinical use and raises complicated ethical problems, the future of stem cells therapies is very bright with the help of accumulating evidence and technology.
Adult ; Adult Stem Cells ; Aging ; Cell Differentiation ; Embryonic Stem Cells ; Humans ; Induced Pluripotent Stem Cells ; Musculoskeletal Pain ; Nerve Growth Factors ; Neuralgia ; Osteoarthritis ; Stem Cell Transplantation ; Stem Cells

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

BACKGROUND: The normal cells derived from human embryonic stem cells (hESCs) are regarded as substitutes for damaged or dysfunctional adult cells. However, tumorigenicity of hESCs remains a major challenge in clinical application of hESC-derived cell transplantation. Previously, we generated monoclonal antibody (MAb) 57-C11 specific to the surface molecule on undifferentiated hESCs. The aim of this study is to prove whether 57-C11-positive hESCs are pluripotent and tumorigenic in immunodeficient mice. METHODS: Undifferentiated hESCs were mixed with retinoic acid (RA)-differentiated hESCs at different ratios prior to 57-C11-mediated separation. To isolate 57-C11-positive hESCs from the mixture, biotinylated 57-C11 and streptavidin-coated magnetic beads were added to the mixture. Unbound 57-C11-negative hESCs were first isolated after applying magnet to the cell mixture, and 57-C11-bound hESCs were then released from the magnetic beads. In order to measure the efficiency of separation, 57-C11-positive or -negative hESCs were counted after isolation. To evaluate the efficiency of teratoma formation in vivo, 57-C11-positive or negative cells were further injected into left and right, respectively, testes of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. RESULTS: Approximately 77~100% of undifferentiated hESCs were isolated after applying 57-C11-coated magnetic beads to the mixed cell populations. Importantly, teratomas were not observed in NOD/SCID mice after the injection of isolated 57-C11-negative hESCs, whereas teratomas were observed with 57-C11-positive hESCs. CONCLUSION: 57-C11-positive hESCs are pluripotent and tumorigenic. The combination of 57-C11 and magnetic beads will be useful to eliminate remaining undifferentiated hESCs for the safe cell transplantation.
Adult ; Animals ; Cell Transplantation ; Human Embryonic Stem Cells* ; Humans* ; Mice ; Teratoma ; Testis ; Transplants ; Tretinoin

Muscle atrophy caused by nerve injury is a common and difficult clinical problem. The development of stem cell researches has opened up a new way for the treatment of nerve injury-induced muscle atrophy. The induced pluripotent stem cells(iPSCs)can differentiate into various types of cells and have more advantages than embryonic stem cells (ESCs). After being transplanted into the damaged area, iPSCs are guided by neurogenic signals to the lesion sites, to repair the damaged nerve, promote generation of axon myelination, rebuild neural circuits and restore physiological function. Meanwhile, iPSCs can also differentiate into muscle cells and promote muscle tissue regeneration. Therefore, it would be possible to attenuate muscle atrophy caused by nerve injury with iPSCs treatment.
Animals ; Disease Models, Animal ; Embryonic Stem Cells ; Humans ; Induced Pluripotent Stem Cells ; cytology ; transplantation ; Muscular Atrophy ; therapy

BACKGROUNDChronic kidney disease (CKD) has become a public health problem. New interventions to slow or prevent disease progression are urgently needed. In this setting, cell therapies associated with regenerative effects are attracting increasing interest. We evaluated the effect of embryonic stem cells (ESCs) on the progression of CKD.

METHODSAdult male Sprague-Dawley rats were subjected to 5/6 nephrectomy. We used pedicled greater omentum flaps packing ESC-loaded gelatin microcryogels (GMs) on the 5/6 nephrectomized kidney. The viability of ESCs within the GMs was detected using in vitro two-photon fluorescence confocal imaging. Rats were sacrificed after 12 weeks. Renal injury was evaluated using serum creatinine, urea nitrogen, 24 h protein, renal pathology, and tubular injury score results. Structural damage was evaluated by periodic acid-Schiff and Masson trichrome staining.

RESULTSIn vitro, ESCs could be automatically loaded into the GMs. Uniform cell distribution, good cell attachment, and viability were achieved from day 1 to 7 in vitro. After 12 weeks, in the pedicled greater omentum flaps packing ESC-loaded GMs on 5/6 nephrectomized rats group, the plasma urea nitrogen levels were 26% lower than in the right nephrectomy group, glomerulosclerosis index was 62% lower and tubular injury index was 40% lower than in the 5/6 nephrectomized rats group without GMs.

CONCLUSIONSIn a rat model of established CKD, we demonstrated that the pedicled greater omentum flaps packing ESC-loaded GMs on the 5/6 nephrectomized kidney have a long-lasting therapeutic rescue function, as shown by the decreased progression of CKD and reduced glomerular injury.

Animals ; Cell Proliferation ; Cryogels ; Disease Progression ; Embryonic Stem Cells ; transplantation ; Gelatin ; administration & dosage ; Kidney ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Rats ; Rats, Sprague-Dawley ; Renal Insufficiency, Chronic ; pathology ; therapy

Neurodegenerative diseases are the hereditary and sporadic conditions which are characterized by progressive neuronal degeneration. Neurodegenerative diseases are emerging as the leading cause of death, disabilities, and a socioeconomic burden due to an increase in life expectancy. There are many neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis, but we have no effective treatments or cures to halt the progression of any of these diseases. Stem cell-based therapy has become the alternative option to treat neurodegenerative diseases. There are several types of stem cells utilized; embryonic stem cells, induced pluripotent stem cells, and adult stem cell (mesenchymal stem cells and neural progenitor cells). In this review, we summarize recent advances in the treatments and the limitations of various stem cell technologies. Especially, we focus on clinical trials of stem cell therapies for major neurodegenerative diseases.
Adult Stem Cells ; Alzheimer Disease ; Amyotrophic Lateral Sclerosis ; Cause of Death ; Cell Transplantation ; Embryonic Stem Cells ; Huntington Disease ; Induced Pluripotent Stem Cells ; Life Expectancy ; Multiple Sclerosis ; Neurodegenerative Diseases* ; Neurons ; Parkinson Disease ; Stem Cells*

The category of chronic liver diseases comprise one of the most common medical diagnoses worldwide. Currently, orthotopic liver transplantation is the only effective treatment for end-stage hepatic disease, but this procedure is associated with many problems, including donor scarcity, operative damage, high cost, risk of immune rejection and lifelong immunosuppressive treatments. Thus, the development of new therapies is highly desirable. Cell therapy with stem cells is increasingly being used to repair damaged tissue or to promote organ regeneration. Stem cells, which possess self-renewal activity as well as differentiation potential, can be categorized as embryonic stem cells (ESCs) or adult stem cells (ASCs), which include hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Recently, placenta-derived mesenchymal stem cells (PD-MSCs) have been reported, and they are attracting much interest in stem cell research for their multiple advantages: 1) no ethical concerns, 2) the ability to obtain abundant cell numbers, 3) multi-lineage differentiation potential, and 4) strong immunosuppressive properties. PD-MSCs differentiate into hepatocyte-like cells when exposed to hepatogenic differentiation-inducing conditions and PD-MSCs transplantation has been shown to enhance hepatic regeneration and/or survival in a rat hepatic failure model by suppressing the progression of fibrosis and apoptosis and activating autophagy. In this review, we will explain the characteristics of several kinds of PD-MSCs and discuss recent studies of the therapeutic potential of PD-MSCs in the repair of liver injury and their utility in regenerative medicine. Although many problems remain to be solved, many studies support the potential for human stem cell therapies, including PD-MSCs, as a promising new technology for the therapeutic regeneration of human liver intractably damaged due to chronic disease and/or toxic and environmental insult.
Adult Stem Cells ; Animals ; Apoptosis ; Autophagy ; Cell Count ; Cell Transplantation ; Cell- and Tissue-Based Therapy ; Chronic Disease ; Diagnosis ; Embryonic Stem Cells ; Fibrosis ; Hematopoietic Stem Cells ; Humans ; Liver ; Liver Diseases ; Liver Failure ; Liver Transplantation ; Mesenchymal Stromal Cells ; Rats ; Regeneration ; Regenerative Medicine ; Stem Cell Research ; Stem Cells* ; Tissue Donors

Induced pluripotent stem cells (iPSC) are specially manipulated cells from somatic cells by the introduction of four factors that are reprogrammed. The properties of iPSC are similar to embryonic stem cells (ESC) characteristic of self-renewal and pluripotency. The technology of reprogramming somatic cells to iPSC enables the generation of patient-specific cells that can be used as powerful tools for drug screening, in vitro models for human disease and autologous transplantation. The iPSC technology provides a priceless resource for regenerative medicine but there are still changing obstacles over the safety of iPSC in avoiding induction of tumorigenicity and maintaining high purity of re-differentiated cells from iPSC to produce more functional cells for cell therapy. A variety of methods to overcome the limitation of iPSC application applied in the clinical setting have been developed. In this review, we summarize the recent progress in iPSC generation and differentiation techniques to facilitate clinical application of iPSC with future potential in regenerative medicine.
Autografts ; Cell- and Tissue-Based Therapy ; Drug Evaluation, Preclinical ; Embryonic Stem Cells ; Humans ; Induced Pluripotent Stem Cells* ; Regenerative Medicine ; Stem Cells* ; Transplantation, Autologous

With their capability to undergo unlimited self-renewal and to differentiate into all cell types in the body, human embryonic stem cells (hESCs) hold great promise in human cell therapy. However, there are limited tools for easily identifying and isolating live hESC-derived cells. To track hESC-derived neural progenitor cells (NPCs), we applied homologous recombination to knock-in the mCherry gene into the Nestin locus of hESCs. This facilitated the genetic labeling of Nestin positive neural progenitor cells with mCherry. Our reporter system enables the visualization of neural induction from hESCs both in vitro (embryoid bodies) and in vivo (teratomas). This system also permits the identification of different neural subpopulations based on the intensity of our fluorescent reporter. In this context, a high level of mCherry expression showed enrichment for neural progenitors, while lower mCherry corresponded with more committed neural states. Combination of mCherry high expression with cell surface antigen staining enabled further enrichment of hESC-derived NPCs. These mCherry(+) NPCs could be expanded in culture and their differentiation resulted in a down-regulation of mCherry consistent with the loss of Nestin expression. Therefore, we have developed a fluorescent reporter system that can be used to trace neural differentiation events of hESCs.
Animals ; Cell Differentiation ; Cell Line ; Embryonic Stem Cells ; cytology ; metabolism ; transplantation ; Gene Knock-In Techniques ; Genes, Reporter ; Homologous Recombination ; Humans ; Luminescent Proteins ; genetics ; Mice ; Mice, SCID ; Nestin ; genetics ; Neural Stem Cells ; cytology ; metabolism ; Neurons ; cytology ; metabolism ; Teratoma ; pathology

The transplantation of neural precursor cells (NPCs) is known to be a promising approach to ameliorating behavioral deficits after stroke in a rodent model of middle cerebral artery occlusion (MCAo). Previous studies have shown that transplanted NPCs migrate toward the infarct region, survive and differentiate into mature neurons to some extent. However, the spatiotemporal dynamics of NPC migration following transplantation into stroke animals have yet to be elucidated. In this study, we investigated the fates of human embryonic stem cell (hESC)-derived NPCs (ENStem-A) for 8 weeks following transplantation into the side contralateral to the infarct region using 7.0T animal magnetic resonance imaging (MRI). T2- and T2*-weighted MRI analyses indicated that the migrating cells were clearly detectable at the infarct boundary zone by 1 week, and the intensity of the MRI signals robustly increased within 4 weeks after transplantation. Afterwards, the signals were slightly increased or unchanged. At 8 weeks, we performed Prussian blue staining and immunohistochemical staining using human-specific markers, and found that high percentages of transplanted cells migrated to the infarct boundary. Most of these cells were CXCR4-positive. We also observed that the migrating cells expressed markers for various stages of neural differentiation, including Nestin, Tuj1, NeuN, TH, DARPP-32 and SV38, indicating that the transplanted cells may partially contribute to the reconstruction of the damaged neural tissues after stroke. Interestingly, we found that the extent of gliosis (glial fibrillary acidic protein-positive cells) and apoptosis (TUNEL-positive cells) were significantly decreased in the cell-transplanted group, suggesting that hESC-NPCs have a positive role in reducing glia scar formation and cell death after stroke. No tumors formed in our study. We also performed various behavioral tests, including rotarod, stepping and modified neurological severity score tests, and found that the transplanted animals exhibited significant improvements in sensorimotor functions during the 8 weeks after transplantation. Taken together, these results strongly suggest that hESC-NPCs have the capacity to migrate to the infarct region, form neural tissues efficiently and contribute to behavioral recovery in a rodent model of ischemic stroke.
Animals ; Apoptosis ; Cell Differentiation ; *Cell Movement ; Embryonic Stem Cells/cytology/metabolism/*transplantation ; Glial Fibrillary Acidic Protein/genetics/metabolism ; Humans ; Infarction, Middle Cerebral Artery/metabolism/pathology/physiopathology/*surgery ; Male ; Neural Stem Cells/cytology/metabolism/*transplantation ; *Psychomotor Performance ; Rats ; Rats, Sprague-Dawley ; Receptors, CXCR4/genetics/metabolism