Implantation of human amniotic epithelial cells prevents the degeneration of nigral dopamine neurons in rats with 6-hydroxydopamine lesions

Perinatal Tissue-Derived Stem Cells: An Emerging Therapeutic Strategy for Challenging Neurodegenerative Diseases

Over the past 20 years, stem cell therapy has been considered a promising option for treating numerous disorders, in particular, neurodegenerative disorders. Stem cells exert neuroprotective and neurodegenerative benefits through different mechanisms, such as the secretion of neurotrophic factors, cell replacement, the activation of endogenous stem cells, and decreased neuroinflammation. Several sources of stem cells have been proposed for transplantation and the restoration of damaged tissue. Over recent decades, intensive research has focused on gestational stem cells considered a novel resource for cell transplantation therapy. The present review provides an update on the recent preclinical/clinical applications of gestational stem cells for the treatment of protein-misfolding diseases including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). However, further studies should be encouraged to translate this promising therapeutic approach into the clinical setting.

Prospects for the Application of Transplantation With Human Amniotic Membrane Epithelial Stem Cells in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multi-organ and systemic autoimmune disease characterized by an imbalance of humoral and cellular immunity. The efficacy and side effects of traditional glucocorticoid and immunosuppressant therapy remain controversial. Recent studies have revealed abnormalities in mesenchymal stem cells (MSCs) in SLE, leading to the application of bone marrow-derived MSCs (BM-MSCs) transplantation technique for SLE treatment. However, autologous transplantation using BM-MSCs from SLE patients has shown suboptimal efficacy due to their dysfunction, while allogeneic mesenchymal stem cell transplantation (MSCT) still faces challenges, such as donor degeneration, genetic instability, and immune rejection. Therefore, exploring new sources of stem cells is crucial for overcoming these limitations in clinical applications. Human amniotic epithelial stem cells (hAESCs), derived from the eighth-day blastocyst, possess strong characteristics including good differentiation potential, immune tolerance with low antigen-presenting ability, and unique immune properties. Hence, hAESCs hold great promise for the treatment of not only SLE but also other autoimmune diseases.

Biological importance of human amniotic membrane in tissue engineering and regenerative medicine

The human amniotic membrane (hAM) is the innermost layer of the placenta. Its distinctive structure and the biological and physical characteristics make it a highly biocompatible material in a variety of regenerative medicine applications. It also acts as a supply of bioactive factors and cells, which indicate the advantages over other tissues. In this review, we firstly discussed the biological properties of hAM-derived cells in vivo or in vitro, along with their stemness of markers, pointing out a promising source of stem cells for regenerative medicine. Then, we systematically summarized current knowledge on the collection, preparation, preservation, and decellularization of hAM, as well as their characteristics helping to improve the understanding of applications in tissue engineering. Finally, we highlighted the recent advances in which hAM has undergone additional modifications to achieve an adequate perspective of regenerative medicine applications. More investigations are required in utilizing appropriate modifications to enhance the therapeutic effectiveness of hAM in the future.

Applications of the amniotic membrane in tissue engineering and regeneration: the hundred-year challenge

The amniotic membrane (Amnio-M) has various applications in regenerative medicine. It acts as a highly biocompatible natural scaffold and as a source of several types of stem cells and potent growth factors. It also serves as an effective nano-reservoir for drug delivery, thanks to its high entrapment properties. Over the past century, the use of the Amnio-M in the clinic has evolved from a simple sheet for topical applications for skin and corneal repair into more advanced forms, such as micronized dehydrated membrane, amniotic cytokine extract, and solubilized powder injections to regenerate muscles, cartilage, and tendons. This review highlights the development of the Amnio-M over the years and the implication of new and emerging nanotechnology to support expanding its use for tissue engineering and clinical applications.

The potential role of multifunctional human amniotic epithelial cells in pancreatic islet transplantation

Pancreatic islet cell transplantation has proven efficacy as a treatment for type 1 diabetes mellitus, chiefly in individuals who are refractory to conventional insulin replacement therapy. At present its clinical use is restricted, firstly by the limited access to suitable donor organs but also due to factors associated with the current clinical transplant procedure which inadvertently impair the long-term functionality of the islet graft. Of note, the physical, biochemical, inflammatory, and immunological stresses to which islets are subjected, either during pretransplant processing or following implantation are detrimental to their sustained viability, necessitating repeated islet infusions to attain adequate glucose control. Progressive decline in functional beta (β)-cell mass leads to graft failure and the eventual re-instatement of exogenous insulin treatment. Strategies which protect and/or preserve optimal islet function in the peri-transplant period would improve clinical outcomes. Human amniotic epithelial cells (HAEC) exhibit both pluripotency and immune-privilege and are ideally suited for use in replacement and regenerative therapies. The HAEC secretome exhibits trophic, anti-inflammatory, and immunomodulatory properties of relevance to islet graft survival. Facilitated by β-cell supportive 3D cell culture systems, HAEC may be integrated with islets bringing them into close spatial arrangement where they may exert paracrine influences that support β-cell function, reduce hypoxia-induced islet injury, and alter islet alloreactivity. The present review details the potential of multifunctional HAEC in the context of islet transplantation, with a focus on the innate capabilities that may counter adverse events associated with the current clinical transplant protocol to achieve long-term islet graft function.

Sub-Regional Differences of the Human Amniotic Membrane and Their Potential Impact on Tissue Regeneration Application

For more than 100 years, the human amniotic membrane (hAM) has been used in multiple tissue regeneration applications. The hAM consists of cells with stem cell characteristics and a rich layer of extracellular matrix. Undoubtedly, the hAM with viable cells has remarkable properties such as the differentiation potential into all three germ layers, immuno-modulatory, and anti-fibrotic properties. At first sight, the hAM seems to be one structural entity. However, by integrating its anatomical location, the hAM can be divided into placental, reflected, and umbilical amniotic membrane. Recent studies show that cells of these amniotic sub-regions differ considerably in their properties such as morphology, structure, and content/release of certain bioactive factors. The aim of this review is to summarize these findings and discuss the relevance of these different properties for tissue regeneration. In summary, reflected amnion seems to be more immuno-modulatory and could have a higher reprogramming efficiency, whereas placental amnion seems to be pro-inflammatory, pro-angiogenic, with higher proliferation and differentiation capacity (e.g., chondrogenic and osteogenic), and could be more suitable for certain graft constructions. Therefore, we suggest that the respective hAM sub-region should be selected in consideration of its desired outcome. This will help to optimize and fine-tune the clinical application of the hAM.

Uncovering the Diversification of Tissue Engineering on the Emergent Areas of Stem Cells, Nanotechnology and Biomaterials

Damaged or disabled tissue is life-threatening due to the lack of proper treatment. Many conventional transplantation methods like autograft, iso-graft and allograft are in existence for ages, but they are not sufficient to treat all types of tissue or organ damages. Stem cells, with their unique capabilities like self-renewal and differentiate into various cell types, can be a potential strategy for tissue regeneration. However, the challenges like reproducibility, uncontrolled propagation and differentiation, isolation of specific kinds of cell and tumorigenic nature made these stem cells away from clinical application. Today, various types of stem cells like embryonic, fetal or gestational tissue, mesenchymal and induced-pluripotent stem cells are under investigation for their clinical application. Tissue engineering helps in configuring the stem cells to develop into a desired viable tissue, to use them clinically as a substitute for the conventional method. The use of stem cell-derived Extracellular Vesicles (EVs) is being studied to replace the stem cells, which decreases the immunological complications associated with the direct administration of stem cells. Tissue engineering also investigates various biomaterials to use clinically, either to replace the bones or as a scaffold to support the growth of stemcells/ tissue. Depending upon the need, there are various biomaterials like bio-ceramics, natural and synthetic biodegradable polymers to support replacement or regeneration of tissue. Like the other fields of science, tissue engineering is also incorporating the nanotechnology to develop nano-scaffolds to provide and support the growth of stem cells with an environment mimicking the Extracellular matrix (ECM) of the desired tissue. Tissue engineering is also used in the modulation of the immune system by using patient-specific Mesenchymal Stem Cells (MSCs) and by modifying the physical features of scaffolds that may provoke the immune system. This review describes the use of various stem cells, biomaterials and the impact of nanotechnology in regenerative medicine.

Human Amniotic Epithelial Cells Alleviate a Mouse Model of Parkinson's Disease Mainly by Neuroprotective, Anti-Oxidative and Anti-Inflammatory Factors

Human amniotic epithelial cells (hAECs) have been reported to have neuroprotective roles in Parkinson's disease (PD) animal models. However, the molecular mechanism is not fully understood. The present study was designed to explore the possible mechanism by which hAECs ameliorate PD symptoms and the important paracrine factors produced by hAECs that attribute to the recovery of dopaminergic neurons. Thus, we performed in vivo and in vitro experiments with hAECs in PD models or lesioned dopaminergic neurons, respectively. First, hAECs were transplanted into the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice and motor deficits were significantly attenuated. Second, the grafts prevented the loss of nigral dopaminergic neurons and promoted the outgrowth of neurites and striatal axon fibers in PD mice. In addition, decreased microglial activation, inflammatory factor levels and MPTP-induced excessive reactive oxygen species (ROS) levels were also observed in hAEC-treated PD mice. In vitro, we found that the conditioned medium (CM) from hAECs promoted the survival of mesencephalic dopaminergic neurons stimulated with 1-methyl-4-phenylpyridine (MPP⁺) and induced neurite outgrowth. Next, analysis of hAEC-CM with an antibody array of 507 soluble target proteins revealed that the levels of many neurotrophic factors, growth factors, neuronal cell adhesion molecule (NrCAM) and anti-inflammatory factors were evidently high. In addition, antibody neutralization experiments showed that many of these factors contributed to the survival and growth of dopaminergic neurons and neurite outgrowth. More importantly, we found that the anti-inflammatory factor interleukin-1 receptor antagonist (IL-1ra) also augmented the survival of dopaminergic neurons, demonstrating for the first time an anti-oxidative and anti-inflammatory role of hAECs in PD mice, which represents a novel molecular mechanism of hAECs in the treatment of PD. The molecular mechanism of hAECs recovering lesioned dopaminergic neurons and attenuating PD symptoms. First, hAECs secret many neurotrophic factors, growth factors, and neuronal cell adhesion molecule (NrCAM) which promote the growth of the damaged dopaminergic neurons and their neurites. Second, hAECs produce many anti-inflammatory factors and other factors contributing to reducing the activation of microglia and suppressing the neuroinflammation. Third, hAECs reduce the excessive ROS levels by upregulating some anti-oxidative signals.

Human Amniotic Epithelial Stem Cells: A Promising Seed Cell for Clinical Applications

Perinatal stem cells have been regarded as an attractive and available cell source for medical research and clinical trials in recent years. Multiple stem cell types have been identified in the human placenta. Recent advances in knowledge on placental stem cells have revealed that human amniotic epithelial stem cells (hAESCs) have obvious advantages and can be used as a novel potential cell source for cellular therapy and clinical application. hAESCs are known to possess stem-cell-like plasticity, immune-privilege, and paracrine properties. In addition, non-tumorigenicity and a lack of ethical concerns are two major advantages compared with embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). All of the characteristics mentioned above and other additional advantages, including easy accessibility and a non-invasive application procedure, make hAESCs a potential ideal cell type for use in both research and regenerative medicine in the near future. This review article summarizes current knowledge on the characteristics, therapeutic potential, clinical advances and future challenges of hAESCs in detail.

Application of human amniotic epithelial cells in regenerative medicine: a systematic review

Human amniotic epithelial cells (hAECs) derived from placental tissues have gained considerable attention in the field of regenerative medicine. hAECs possess embryonic stem cell-like proliferation and differentiation capabilities, and adult stem cell-like immunomodulatory properties. Compared with other types of stem cell, hAECs have special advantages, including easy isolation, plentiful numbers, the obviation of ethical debates, and non-immunogenic and non-tumorigenic properties. During the past two decades, the therapeutic potential of hAECs for treatment of various diseases has been extensively investigated. Accumulating evidence has demonstrated that hAEC transplantation helps to repair and rebuild the function of damaged tissues and organs by different molecular mechanisms. This systematic review focused on summarizing the biological characteristics of hAECs, therapeutic applications, and recent advances in treating various tissue injuries and disorders. Relevant studies published in English from 2000 to 2020 describing the role of hAECs in diseases and phenotypes were comprehensively sought out using PubMed, MEDLINE, and Google Scholar. According to the research content, we described the major hAEC characteristics, including induced differentiation plasticity, homing and differentiation, paracrine function, and immunomodulatory properties. We also summarized the current status of clinical research and discussed the prospects of hAEC-based transplantation therapies. In this review, we provide a comprehensive understanding of the therapeutic potential of hAECs, including their use for cell replacement therapy as well as secreted cytokine and exosome biotherapy. Moreover, we showed that the powerful immune-regulatory function of hAECs reveals even more possibilities for their application in the treatment of immune-related diseases. In the future, establishing the optimal culture procedure, achieving precise and accurate treatment, and enhancing the therapeutic potential by utilizing appropriate preconditioning and/or biomaterials would be new challenges for further investigation.

Potential application of aminiotic stem cells in veterinary medicine

In regenerative medicine stem cell biology has become one of the most interesting and more often studied subject. The amniotic membrane is the innermost layer of the fetal membranes and is considered a potential tool to treat many pathologies. It is used because it can be collected from discarded fetal material and is a rich source of stem cells with high proliferation and plasticity ratio capable of proliferating and differentiate in vitro. We propose to elucidate the characteristics and potencial clinical application of cells derived of amniotic membrane in veterinary medicine.

Therapeutic Potential of Human Amniotic Epithelial Cells on Injuries and Disorders in the Central Nervous System

Despite recent advances in neurosurgery and pharmaceuticals, contemporary treatments are ineffective in restoring lost neurological functions in patients with injuries and disorders of the central nervous system (CNS). Therefore, novel and effective therapies are urgently needed. Recent studies have indicated that stem cells, including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and mesenchymal stem cells (MSCs), could repair/replace damaged or degenerative neurons and improve functional recovery in both preclinical and clinical trials. However, there are many unanswered questions and unsolved issues regarding stem cell therapy in terms of potency, stability, oncogenicity, immune response, cell sources, and ethics. Currently, human amniotic epithelial cells (hAECs) derived from the amnion exhibit considerable advantages over other stem cells and have drawn much attention from researchers. hAECs are readily available, pose no ethical concerns, and have little risk of tumorigenicity and immunogenicity. Mounting evidence has shown that hAECs can promote neural cell survival and regeneration, repair affected neurons, and reestablish damaged neural connections. It is suggested that hAECs may be the most promising candidate for cell-based therapy of neurological diseases. In this review, we mainly focus on recent advances and potential applications of hAECs for treating various CNS injuries and neurodegenerative disorders. We also discuss current hurdles and challenges regarding hAEC therapies.

Concise Review: Fetal Membranes in Regenerative Medicine: New Tricks from an Old Dog?

The clinical application of the fetal membranes dates back to nearly a century. Their use has ranged from superficial skin dressings to surgical wound closure. The applications of the fetal membranes are constantly evolving, and key to this is the uncovering of multiple populations of stem and stem-like cells, each with unique properties that can be exploited for regenerative medicine. In addition to pro-angiogenic and immunomodulatory properties of the stem and stem-like cells arising from the fetal membranes, the dehydrated and/or decellularized forms of the fetal membranes have been used to support the growth and function of other cells and tissues, including adipose-derived mesenchymal stem cells. This concise review explores the biological origin of the fetal membranes, a history of their use in medicine, and recent developments in the use of fetal membranes and their derived stem and stem-like cells in regenerative medicine. Stem Cells Translational Medicine 2017;6:1767-1776.

Human Amniotic Membrane and Amniotic Membrane-Derived Cells: How Far Are We from Their Use in Regenerative and Reconstructive Urology?

Human amniotic membrane (hAM) is the innermost layer of fetal membranes, which surrounds the developing fetus and forms the amniotic cavity. hAM and hAM-derived cells possess many properties that make them suitable for use in regenerative medicine, such as low immunogenicity, promotion of epithelization, anti-inflammatory properties, angiogenic and antiangiogenic properties, antifibrotic properties, antimicrobial properties, and anticancer properties. Many pathological conditions of the urinary tract lead to organ damage or complete loss of function. Consequently, the reconstruction or replacement of damaged organs is needed, which makes searching for new approaches in regenerative and reconstructive urology a necessity. The use of hAM for treating defects in kidneys, ureters, urinary bladder, and urethra was tested in vitro in cell cultures and in vivo in mice, rats, rabbits, cats, dogs, and also in humans. These studies confirmed the advantages and the potential of hAM for use in regenerative and reconstructive urology as stated above. However, they also pointed out a few concerns we have to take into consideration. These are (1) the lack of a standardized protocol in hAM preparation and storage, (2) the heterogeneity of hAM, and especially (3) low mechanical strength of hAM. Before any wider use of hAM for treating urological defects, the protocols for preparation and storage will need to be standardized, followed by more studies on larger animals and clinical trials, which will altogether extensively assess the potential of hAM use in urological patients.

Oxygen Tension Strongly Influences Metabolic Parameters and the Release of Interleukin-6 of Human Amniotic Mesenchymal Stromal Cells In Vitro

The human amniotic membrane (hAM) has been used for tissue regeneration for over a century. In vivo (in utero), cells of the hAM are exposed to low oxygen tension (1-4% oxygen), while the hAM is usually cultured in atmospheric, meaning high, oxygen tension (20% oxygen). We tested the influence of oxygen tensions on mitochondrial and inflammatory parameters of human amniotic mesenchymal stromal cells (hAMSCs). Freshly isolated hAMSCs were incubated for 4 days at 5% and 20% oxygen. We found 20% oxygen to strongly increase mitochondrial oxidative phosphorylation, especially in placental amniotic cells. Oxygen tension did not impact levels of reactive oxygen species (ROS); however, placental amniotic cells showed lower levels of ROS, independent of oxygen tension. In contrast, the release of nitric oxide was independent of the amniotic region but dependent on oxygen tension. Furthermore, IL-6 was significantly increased at 20% oxygen. To conclude, short-time cultivation at 20% oxygen of freshly isolated hAMSCs induced significant changes in mitochondrial function and release of IL-6. Depending on the therapeutic purpose, cultivation conditions of the cells should be chosen carefully for providing the best possible quality of cell therapy.

Multilineage potential research of Beijing duck amniotic mesenchymal stem cells

Amnion, which is usually discarded as medical waste, is considered as abundant sources for mesenchymal stem cells. In human and veterinary medicine, the multipotency of mesenchymal stem cells derived from amnion (AMSCs) together with their plasticity, self-renewal, low immunogenicity and nontumorigenicity characteristics make AMSCs a promising candidate cell for cell-based therapies and tissue engineering. However, up till now, the multipotential characteristics and therapeutic potential of AMSCs on preclinical studies remain uncertain. In this work, we successfully obtained AMSCs from Beijing duck embryos in vitro, and also attempted to detect their biological characteristics. The isolated AMSCs were phenotypically identified, the growth kinetics and karyotype were tested. Also, the cells were positive for MSCs-related markers (CD29, CD71, CD105, CD166, Vimentin and Fibronection), while the expression of CD34 and CD45 were undetectable. Additionally, AMSCs also expressed the pluripotent marker gene OCT4. Particularly, when appropriately induced, AMSCs could be induced to trans-differentiate into adipocytes, osteoblasts, chondrocytes and neurocytes in vitro. Together, these results demonstrated that the isolated AMSCs maintained their stemness and proliferation in vitro, which may be useful for future cell therapy in regenerative medicine.

Cardiac Restoration Stemming From the Placenta Tree: Insights From Fetal and Perinatal Cell Biology

Efficient cardiac repair and ultimate regeneration still represents one of the main challenges of modern medicine. Indeed, cardiovascular disease can derive from independent conditions upsetting heart structure and performance: myocardial ischemia and infarction (MI), pharmacological cardiotoxicity, and congenital heart defects, just to name a few. All these disorders have profound consequences on cardiac tissue, inducing the onset of heart failure over time. Since the cure is currently represented by heart transplantation, which is extremely difficult due to the shortage of donors, much effort is being dedicated to developing innovative therapeutic strategies based on stem cell exploitation. Among the broad scenario of stem/progenitor cell subpopulations, fetal and perinatal sources, namely amniotic fluid and term placenta, have gained interest due to their peculiar regenerative capacity, high self-renewal capability, and ease of collection from clinical waste material. In this review, we will provide the state-of-the-art on fetal perinatal stem cells for cardiac repair and regeneration. We will discuss different pathological conditions and the main therapeutic strategies proposed, including cell transplantation, putative paracrine therapy, reprogramming, and tissue engineering approaches.

Fetal Membranes-Derived Stem Cells Microenvironment

Recently, the regenerative medicine has been trying to congregate different areas such as tissue engineering and cellular therapy, in order to offer effective treatments to overcome several human and veterinary medical problems. In this regard, fetal membranes have been proposed as a powerful source for obtainment of multipotent stem cells with low immunogenicity, anti-inflammatory properties and nontumorigenicity properties for the treatment of several diseases, including replacing cells lost due to tissue injuries or degenerative diseases. Morpho-physiological data have shown that fetal membranes, especially the yolk sac and amnion play different functions according to the gestational period, which are direct related to the features of the microenvironment that their cells are subject. The characteristics of the microenvironment affect or controls important cellular events involved with proliferation, division and maintenance of the undifferentiated stage or differentiation, especially acting on the extracellular matrix components. Considering the importance of the microenvironment and the diversity of embryonic and fetal membrane-derived stem cells, this chapter will addressed advances in the isolation, phenotyping, characteristics of the microenvironment, and applications of yolk sac and amniotic membrane-derived stem cells for human and veterinary regenerative medicine.

Enhanced differentiation of human amniotic fluid-derived stem cells into insulin-producing cells in vitro

AIMS/INTRODUCTION

To investigate the ability of human amniotic fluid stem cells (hAFSCs) to differentiate into insulin-producing cells.

MATERIALS AND METHODS

hAFSCs were induced to differentiate into pancreatic cells by a multistep protocol. The expressions of pancreas-related genes and proteins, including pancreatic and duodenal homeobox-1, insulin, and glucose transporter 2, were detected by polymerase chain reaction and immunofluorescence. Insulin secreted from differentiated cells was tested by enzyme-linked immunosorbent assay.

RESULTS

hAFSCs were successfully isolated from amniotic fluid that expressed the pluripotent markers of embryonic stem cells, such as Oct3/4, and mesenchymal stem cells, such as integrin β-1 and ecto-5'-nucleotidase. Here, we first obtained the hAFSCs that expressed pluripotent marker stage-specific embryonic antigen 1. Real-time polymerase chain reaction analysis showed that pancreatic and duodenal homeobox-1, paired box gene 4 and paired box gene 6 were expressed in the early phase of induction, and then stably expressed in the differentiated cells. The pancreas-related genes, such as insulin, glucokinase, glucose transporter 2 and Nkx6.1, were expressed in the differentiated cells. Immunofluorescence showed that these differentiated cells co-expressed insulin, C-peptide, and pancreatic and duodenal homeobox-1. Insulin was released in response to glucose stimulation in a manner similar to that of adult human islets.

CONCLUSIONS

The present study showed that hAFSCs, under selective culture conditions, could differentiate into islet-like insulin-producing cells, which might be used as a potential source for transplantation in patients with type 1 diabetes mellitus.

Amnion-derived stem cell transplantation: A novel treatment for neurological disorders

In this review, we evaluated the literature reporting the use of amniotic stem cells (ASCs) in regenerative medicine for the treatment of neurological disorders. There is an increasing amount of evidence that indicates the exacerbation of the primary injury by inflammation in neurological disorders characterized by rampant inflammation, thereby increasing damage to the central nervous system (CNS). To address this, we focus on the amnion cells' anti-inflammatory properties, which make their transplantation a promising treatment for these disorders. In addition, we offered insights into new applications of the ASC in the fields of regenerative medicine and tissue engineering.

Stem cell properties and neural differentiation of sheep amniotic epithelial cells

This study was designed to verify the stem cell properties of sheep amniotic epithelial cells and their capacity for neural differentiation. Immunofluorescence microscopy and reverse transcription-PCR revealed that the sheep amniotic epithelial cells were positive for the embryonic stem cell marker proteins SSEA-1, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81, and the totipotency-associated genes Oct-4, Sox-2 and Rex-1, but negative for Nanog. Amniotic epithelial cells expressed β-III-tubulin, glial fibrillary acidic protein, nestin and microtubule-associated protein-2 at 28 days after induction with serum-free neurobasal-A medium containing B-27. Thus, sheep amniotic epithelial cells could differentiate into neurons expressing β-III-tubulin and microtubule-associated protein-2, and glial-like cells expressing glial fibrillary acidic protein, under specific conditions.

Stem cells from fetal membranes and amniotic fluid: markers for cell isolation and therapy

Stem cell therapy is in constant need of new cell sources to conceive regenerative medicine approaches for diseases that are still without therapy. Scientists drew the attention toward amniotic membrane and amniotic fluid stem cells, since these sources possess many advantages: first of all as cells can be extracted from discarded foetal material it is inexpensive, secondly abundant stem cells can be obtained and finally, these stem cell sources are free from ethical considerations. Many studies have demonstrated the differentiation potential in vitro and in vivo toward mesenchymal and non-mesenchymal cell types; in addition the immune-modulatory properties make these cells a good candidate for allo- and xenotransplantation. This review offers an overview on markers characterisation and on the latest findings in pre-clinical or clinical setting of the stem cell populations isolated from these sources.

Fetal membranes as a source of stem cells

In recent years, a constant growth of knowledge and clinical applications of stem cells have been observed. Mesenchymal stromal cells, also described as mesenchymal stem cells (MSCs) represent a particular cell type for research and therapy because of their ability to differentiate into mesodermal lineage cells. The most investigated source of MSCs is bone marrow (BM). Yet, collection of BM is an invasive procedure associated with significant discomfort to the patient. The procedure results in a relatively low number of these cells, which can decrease with donor's age. Therefore, it seems to be very important to find other sources of mesenchymal stem cells nowadays. A human placenta, which is routinely discarded postpartum, in spite of its natural aging process, is still a rich source of stem cells capable to proliferate and in vitro differentiate in many directions. Besides homing and differentiation in the area of injury, MSCs there elicit strong paracrine effects stimulating the processes of repair. In this review, we focus on the biology, characteristics and potential clinical applications of cells derived from human fetal membranes: amnion and chorion.

In toto differentiation of human amniotic membrane towards the Schwann cell lineage

Human amniotic membrane (hAM) is a tissue containing cells with proven stem cell properties. In its decellularized form it has been successfully applied as nerve conduit biomaterial to improve peripheral nerve regeneration in injury models. We hypothesize that viable hAM without prior cell isolation can be differentiated towards the Schwann cell lineage to generate a possible alternative to commonly applied tissue engineering materials for nerve regeneration. For in vitro Schwann cell differentiation, biopsies of hAM of 8 mm diameter were incubated with a sequential order of neuronal induction and growth factors for 21 days and characterized for cellular viability and the typical glial markers glial fibrillary acidic protein (GFAP), S100β, p75 and neurotrophic tyrosine kinase receptor (NTRK) using immunohistology. The secretion of the neurotrophic factors brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF) was quantified by ELISA. The hAM maintained high viability, especially under differentiation conditions (90.2 % ± 41.6 day 14; 80.0 % ± 44.5 day 21 compared to day 0). Both, BDNF and GDNF secretion was up-regulated upon differentiation. The fresh membrane stained positive for GFAP and p75 and NTRK, which was strongly increased after culture in differentiation conditions. Especially the epithelial layer within the membrane exhibited a change in morphology upon differentiation forming a multi-layered epithelium with intense accumulations of the marker proteins. However, S100β was expressed at equal levels and equal distribution in fresh and cultured hAM conditions. Viable hAM may be a promising alternative to present formulations used for peripheral nerve regeneration.

MePR: a novel human mesenchymal progenitor model with characteristics of pluripotency

Human embryo stem cells or adult tissues are excellent models for discovery and characterization of differentiation processes. The aims of regenerative medicine are to define the molecular and physiological mechanisms that govern stem cells and differentiation. Human mesenchymal stem cells (hMSCs) are multipotent adult stem cells that are able to differentiate into a variety of cell types under controlled conditions both in vivo and in vitro, and they have the remarkable ability of self-renewal. hMSCs derived from amniotic fluid and characterized by the expression of Oct-4 and Nanog, typical markers of pluripotent cells, represent an excellent model for studies on stemness. Unfortunately, the limited amount of cells available from each donation and, above all, the limited number of replications do not allow for detailed studies. Here, we report on the immortalization and characterization of novel mesenchymal progenitor (MePR) cell lines from amniotic fluid-derived hMSCs, whose biological properties are similar to primary amniocytes. Our data indicate that MePR cells display the multipotency potential and differentiation rates of hMSCs, thus representing a useful model to study both mechanisms of differentiation and pharmacological approaches to induce selective differentiation. In particular, MePR-2B cells, which carry a bona fide normal karyotype, might be used in basic stem cell research, leading to the development of new approaches for stem cell therapy and tissue engineering.

Placental stem cell correction of murine intermediate maple syrup urine disease

There is improved survival and partial metabolic correction of a mouse intermediate maple syrup urine disease (iMSUD) model after allogenic hepatocyte transplantation, confirming that a small number of enzyme-proficient liver-engrafted cells can improve phenotype. However, clinical shortages of suitable livers for hepatocyte isolation indicate a need for alternative cell sources. Human amnion epithelial cells (hAECs) share stem cell characteristics without the latter's safety and ethical concerns and differentiate to hepatocyte-like cells. Eight direct hepatic hAEC transplantations were performed in iMSUD mice over the first 35 days beginning at birth; animals were provided a normal protein diet and sacrificed at 35 and 100 days. Treatment at the neonatal stage is clinically relevant for MSUD and may offer a donor cell engraftment advantage. Survival was significantly extended and body weight was normalized in iMSUD mice receiving hAEC transplantations compared with untreated iMSUD mice, which were severely cachectic and died ≤28 days after birth. Branched chain α-keto acid dehydrogenase enzyme activity was significantly increased in transplanted livers. The branched chain amino acids leucine, isoleucine, valine, and alloisoleucine were significantly improved in serum and brain, as were other large neutral amino acids.

CONCLUSION

Placental-derived stem cell transplantation lengthened survival and corrected many amino acid imbalances in a mouse model of iMSUD. This highlights the potential for their use as a viable alternative clinical therapy for MSUD and other liver-based metabolic diseases.

Transplantation-potential-related biological properties of decidua basalis mesenchymal stem cells from maternal human term placenta

Human placental decidua basalis originates from the maternal side of the placenta and has been described as a source of mesenchymal stem cells (MSCs). However, for its application in tissue regeneration and repair, the transplantation-potential-related biological properties of decidua-basalis-derived mesenchymal stem cells (DBMSCs) remain to be elucidated. We obtained DBMSCs through enzymatic digestion and density gradient centrifugation and confirmed their capacity to differentiate into cell types of the mesodermal lineage, such as osteoblasts, adipocytes and chondroblasts. Karyotype analysis showed that the isolated DBMSCs maintained chromosomal stability after long-term culture in vitro. Growth kinetics and ultrastructural observation revealed a high level of DBMSC proliferative activity. In addition, DBMSCs showed immunosuppressive properties by suppressing both mitogen- and alloantigen-induced peripheral lymphocyte proliferation. All of these properties suggest that DBMSCs, which are abundant and easily accessible, are a novel potential source of seed cells for cell transplantation treatments.

Post-stroke inflammation and the potential efficacy of novel stem cell therapies: focus on amnion epithelial cells

Ischemic stroke is a debilitating disease for which there are currently no effective treatments besides the clot-buster, tissue plasminogen activator (t-PA), which is administered to less than 10% of patients due to a limited (4.5 h) time window of efficacy. Thus, there is an urgent need for novel therapies that can prevent or reverse the effects of stroke-induced brain injury. Recent encouraging reports have revealed that stem cells derived from human tissue, including embryonic, induced pluripotent, neural, and mesenchymal cells, can rescue injured brain tissue and improve functional recovery in experimental models of stroke. However, there are potentially major limitations to each of these types of stem cells that may ultimately prevent or restrict their use as viable mainstream treatment options for stroke patients. Conversely, stem cells derived from the placenta, such as human amnion epithelial cells (hAECs), appear to have several important advantages over other stem cell lineages, in particular their non-tumorigenic and non-immunogenic characteristics. Surprisingly, so far hAECs have received little attention as a potential stroke therapy. This brief review will firstly describe the inflammatory response and immune cell involvement following stroke, and then consider the potential for hAECs to improve stroke outcome given their unique characteristics. These actions of hAECs may involve a reduction of local inflammation and modulation of the immune response, promotion of neural recovery, differentiation into neural tissue, re-innervation of lost connections, and secretion of necessary cytokines, growth factors, hormones and/or neurotransmitters to restore cellular function.

Applications of amniotic membrane and fluid in stem cell biology and regenerative medicine

The amniotic membrane (AM) and amniotic fluid (AF) have a long history of use in surgical and prenatal diagnostic applications, respectively. In addition, the discovery of cell populations in AM and AF which are widely accessible, nontumorigenic and capable of differentiating into a variety of cell types has stimulated a flurry of research aimed at characterizing the cells and evaluating their potential utility in regenerative medicine. While a major focus of research has been the use of amniotic membrane and fluid in tissue engineering and cell replacement, AM- and AF-derived cells may also have capabilities in protecting and stimulating the repair of injured tissues via paracrine actions, and acting as vectors for biodelivery of exogenous factors to treat injury and diseases. Much progress has been made since the discovery of AM and AF cells with stem cell characteristics nearly a decade ago, but there remain a number of problematic issues stemming from the inherent heterogeneity of these cells as well as inconsistencies in isolation and culturing methods which must be addressed to advance the field towards the development of cell-based therapies. Here, we provide an overview of the recent progress and future perspectives in the use of AM- and AF-derived cells for therapeutic applications.

Potential antitumor therapeutic strategies of human amniotic membrane and amniotic fluid-derived stem cells

As stem cells are capable of self-renewal and can generate differentiated progenies for organ development, they are considered as potential source for regenerative medicine and tissue replacement after injury or disease. Along with this capacity, stem cells have the therapeutic potential for treating human diseases including cancers. According to the origins, stem cells are broadly classified into two types: embryonic stem cells (ESCs) and adult stem cells. In terms of differentiation potential, ESCs are pluripotent and adult stem cells are multipotent. Amnion, which is a membranous sac that contains the fetus and amniotic fluid and functions in protecting the developing embryo during gestation, is another stem cell source. Amnion-derived stem cells are classified as human amniotic membrane-derived epithelial stem cells, human amniotic membrane-derived mesenchymal stem cells and human amniotic fluid-derived stem cells. They are in an intermediate stage between pluripotent ESCs and lineage-restricted adult stem cells, non-tumorigenic, and contribute to low immunogenicity and anti-inflammation. Furthermore, they are easily available and do not cause any controversial issues in their recovery and applications. Not only are amnion-derived stem cells applicable in regenerative medicine, they have anticancer capacity. In non-engineered stem cells transplantation strategies, amnion-derived stem cells effectively target the tumor and suppressed the tumor growth by expressing cytotoxic cytokines. Additionally, they also have a potential as novel delivery vehicles transferring therapeutic genes to the cancer formation sites in gene-directed enzyme/prodrug combination therapy. Owing to their own advantageous properties, amnion-derived stem cells are emerging as a new candidate in anticancer therapy.

A comparison of mesenchymal precursor cells and amnion epithelial cells for enhancing cervical interbody fusion in an ovine model

BACKGROUND

Rapid, reliable fusion is the goal in anterior cervical diskectomy and fusion. Iliac crest autograft has a high rate of donor-site morbidity. Alternatives such as bone graft substitutes lack osteoinductivity, and recombinant bone morphogenetic proteins risk life-threatening complications. Both allogeneic mesenchymal precursor cells (MPCs) and amnion derived epithelial cells (AECs) have osteogenic potential.

OBJECTIVE

To compare for the first time the capacity of MPCs and AECs to promote osteogenesis in an ovine model.

METHODS

Five groups of 2-year-old ewes were subjected to C3-4 anterior cervical diskectomy and fusion with a Fidji interbody cage packed with iliac crest autograft alone (group A; n = 6), hydroxyapatite-tricalcium phosphate Mastergraft granules (HA/TCP) alone (group B; n = 6), HA/TCP containing 5 million MPCs (group C; n = 6), or HA/TCP containing 5 million AECs (group D; n = 5); group E was made up of age-matched nonoperative controls (n = 6). At 3 months, animals were euthanized and quantitative multislice computed tomography, functional radiography, biomechanics, histology, and histomorphometry were performed.

RESULTS

No procedure- or cell-related adverse events were observed. There was significantly more fusion in the MPC group (C) than in group A, B, or D. Computed tomography scan at 3 months revealed that 5 of 6 MPC-treated animals (83%) had continuous bony bridging compared with 0 of 5 AEC-treated and only 1 of 6 autograft- and 2 of 6 HA/TCP-treated animals (P = .01).

CONCLUSION

Implantation of allogeneic MPCs in combination with HA/TCP within an interbody spacer facilitates interbody fusion after diskectomy. The earlier, more robust fusion observed with MPCs relative to autograft and HA/TCP bone substitute indicates that this approach may offer a therapeutic benefit.

Tissue engineering a fetal membrane

The aim of this study was to construct an artificial fetal membrane (FM) by combination of human amniotic epithelial stem cells (hAESCs) and a mechanically enhanced collagen scaffold containing encapsulated human amniotic stromal fibroblasts (hASFs). Such a tissue-engineered FM may have the potential to plug structural defects in the amniotic sac after antenatal interventions, or to prevent preterm premature rupture of the FM. The hAESCs and hASFs were isolated from human fetal amniotic membrane (AM). Magnetic cell sorting was used to enrich the hAESCs by positive ATP-binding cassette G2 selection. We investigated the use of a laminin/fibronectin (1:1)-coated compressed collagen gel as a novel scaffold to support the growth of hAESCs. A type I collagen gel was dehydrated to form a material mimicking the mechanical properties and ultra-structure of human AM. hAESCs successfully adhered to and formed a monolayer upon the biomimetic collagen scaffold. The resulting artificial membrane shared a high degree of similarity in cell morphology, protein expression profiles, and structure to normal fetal AM. This study provides the first line of evidence that a compacted collagen gel containing hASFs could adequately support hAESCs adhesion and differentiation to a degree that is comparable to the normal human fetal AM in terms of structure and maintenance of cell phenotype.

Amnion-derived stem cells: in quest of clinical applications

In the promising field of regenerative medicine, human perinatal stem cells are of great interest as potential stem cells with clinical applications. Perinatal stem cells could be isolated from normally discarded human placentae, which are an ideal cell source in terms of availability, the fewer number of ethical concerns, less DNA damage, and so on. Numerous studies have demonstrated that some of the placenta-derived cells possess stem cell characteristics like pluripotent differentiation ability, particularly in amniotic epithelial (AE) cells. Term human amniotic epithelium contains a relatively large number of stem cell marker-positive cells as an adult stem cell source. In this review, we introduce a model theory of why so many AE cells possess stem cell characteristics. We also describe previous work concerning the therapeutic applications and discuss the pluripotency of the AE cells and potential pitfalls for amnion-derived stem cell research.

Stem cells in microfluidics

Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened, and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in vivo-like microenvironments which stimulate cell proliferation and differentiation is still lacking. In this paper, recent cell studies using microfluidic systems are first introduced. The various miniature systems for cell culture, sorting and isolation, and stimulation are then systematically reviewed. The main focus of this review is on papers published in recent years studying stem cells by using microfluidic technology. This review aims to provide experts in microfluidics an overview of various microfluidic systems for stem cell research.

Human amniotic membrane as an alternative source of stem cells for regenerative medicine

The human amniotic membrane (HAM) is a highly abundant and readily available tissue. This amniotic tissue has considerable advantageous characteristics to be considered as an attractive material in the field of regenerative medicine. It has low immunogenicity, anti-inflammatory properties and their cells can be isolated without the sacrifice of human embryos. Since it is discarded post-partum it may be useful for regenerative medicine and cell therapy. Amniotic membranes have already been used extensively as biologic dressings in ophthalmic, abdominal and plastic surgery. HAM contains two cell types, from different embryological origins, which display some characteristic properties of stem cells. Human amnion epithelial cells (hAECs) are derived from the embryonic ectoderm, while human amnion mesenchymal stromal cells (hAMSCs) are derived from the embryonic mesoderm. Both populations have similar immunophenotype and multipotential for in vitro differentiation into the major mesodermal lineages, however they differ in cell yield. Therefore, HAM has been proposed as a good candidate to be used in cell therapy or regenerative medicine to treat damaged or diseased tissues.

Review: Preclinical studies on placenta-derived cells and amniotic membrane: an update

Recent years have seen considerable advances in our knowledge of the biology and properties of stem/progenitor cells isolated from placental tissues. This has encouraged researchers to address the potential effects of these cells in animal models of different diseases, resulting in increasing expectations regarding their possible utility for cell-based therapeutic applications. This rapidly evolving research field is also enriched by studies aimed at expanding the use of the whole amniotic membrane (AM), a well-known surgical material, for pathological conditions other than those tested so far and for which clinical applications already exist. In this review, we provide an update on studies that have been performed with placenta-derived cells and fragments of the entire AM to validate their potential clinical applications in a variety of diseases, in particular those associated with degenerative processes induced by inflammatory and fibrotic mechanisms. We also offer, as far as possible, insight into the interpretation and suggested mechanisms to explain the most important outcomes achieved to date.

Amniotic fluid-derived mesenchymal stem cells lead to bone differentiation when cocultured with dental pulp stem cells

Mesenchymal stem cells are present in many tissues of the human body, including amniotic fluid (AF) and dental pulp (DP). Stem cells of both AF and DP give rise to a variety of differentiated cells. In our experience, DP stem cells (DPSCs) display a high capacity to produce bone. Therefore, our aim was to investigate if AF-derived stem cells (AFSCs) were able to undergo bone differentiation in the presence of DPSCs. AFSCs were seeded under three different conditions: (i) cocultured with DPSCs previously differentiated into osteoblasts; (ii) cultured in the conditioned medium of osteoblast-differentiated DPSCs; (iii) cultured in the osteogenic medium supplemented with vascular endothelial growth factor and bone morphogenetic protein-2 (BMP-2). Results showed that AFSCs were positive for mesenchymal markers, and expressed high levels of Tra1-60, Tra1-80, BMPR1, BMPR2, and BMP-2. In contrast, AFSCs were negative for epithelial and hematopoietic/endothelial markers. When AFSCs were cocultured with DPSCs-derived osteoblasts, they differentiated into osteoblasts. A similar effect was observed when AFSCs were cultured in the presence of a conditioned medium originated from DPSCs. We found that osteoblasts derived from DPSCs released large amounts of BMP-2 and vascular endothelial growth factor into the culture medium and that those morphogens significantly upregulate RUNX-2 gene, stimulating osteogenesis. This study highlights the mechanisms of osteogenesis and strongly suggests that the combination of AFSCs with DPSCs may provide a rich source of soluble proteins useful for bone engineering purposes.

In vitro differentiation of human amniotic fluid-derived cells: augmentation towards a neuronal dopaminergic phenotype

Amniotic fluid is known to yield a number of cell types which are multipotent, ethically derived, genetically stable, easily grown, expanded and possess favourable immunogenicity, which has resulted in an increasing interest for use in various neuronal disorders such as Parkinson's disease. The neuronal potential of cells derived from the adherent fraction of amniotic fluid, routinely taken by amniocentesis, are least explored. The aim of the present study was to investigate the capacity of these cells for neuronal and dopaminergic differentiation using in vitro differentiation protocols with canonical inductive factors not previously tested. To do this, samples derived from multiple donors were grown under four conditions: standard serum-containing media, NB (neurobasal) media designed specifically for propagation and maintenance of neuronal cells, NB media with addition of retinoic acid and BDNF (brain-derived neurotrophic factor) for NI (neuronal induction), and NB media with addition of FGF8 (fibroblast growth factor-8) and Shh (sonic hedgehog) after NI. Our results showed the presence of multiple neuronal markers after growth in serum-containing medium [TUJ1, MAP2, NF-M, TH (tyrosine hydroxylase)], which was significantly up-regulated after serum withdrawal in NB medium alone with induction of NeuN (neuronal nuclei) and NSE (neuron-specific enolase). NI and DA.I (dopaminergic induction) was accompanied by further increases in expression and a distinct transition to a sustained neuronal morphology. Western blot analysis confirmed increasing TH expression and NURR1, expressed in base serum-containing media, found to be down-regulated after induction. In conclusion, these cells possess a highly favourable base neuronal and dopaminergic prepotential, which may easily be accentuated by standard induction protocols.

Human amniotic epithelial cells induce localized cell-mediated immune privilege in vitro: implications for pancreatic islet transplantation

Chronic systemic immunosuppression in cell replacement therapy restricts its clinical application. This study sought to explore the potential of cell-based immune modulation as an alternative to immunosuppressive drug therapy in the context of pancreatic islet transplantation. Human amniotic epithelial cells (AEC) possess innate anti-inflammatory and immunosuppressive properties that were utilized to create localized immune privilege in an in vitro islet cell culture system. Cellular constructs composed of human islets and AEC (islet/AEC) were bioengineered under defined rotational cell culture conditions. Insulin secretory capacity was validated by glucose challenge and immunomodulatory potential characterized using a peripheral blood lymphocyte (PBL) proliferation assay. Results were compared to control constructs composed of islets or AEC cultured alone. Studies employing AEC-conditioned medium examined the role of soluble factors, and fluorescence immunocytochemistry was used to identify putative mediators of the immunosuppressive response in isolated AEC monocultures. Sustained, physiologically appropriate insulin secretion was observed in both islets and islet/AEC constructs. Activation of resting PBL proliferation occurred on exposure to human islets alone but this response was significantly (p < 0.05) attenuated by the presence of AEC and AEC-conditioned medium. Mitogen (phytohaemagglutinin, 5 μg/ml)-induced PBL proliferation was sustained on contact with isolated islets but abrogated by AEC, conditioned medium, and the islet/AEC constructs. Immunocytochemical analysis of AEC monocultures identified a subpopulation of cells that expressed the proapoptosis protein Fas ligand. This study demonstrates that human islet/AEC constructs exhibit localized immunosuppressive properties with no impairment of β-cell function. The data suggest that transplanted islets may benefit from the immune privilege status conferred on them as a consequence of their close proximity to human AEC. Such an approach may reduce the need for chronic systemic immunosuppression, thus making islet transplantation a more attractive treatment option for the management of insulin-dependent diabetes.

Isolation and characterization of mesenchymal stem cells from human amniotic membrane

INTRODUCTION

The human amniotic membrane is a highly abundant and readily available tissue that may be useful for regenerative medicine and cell therapy.

AIM

To compare two previously published protocols for the isolation of human amnion mesenchymal stromal cells (hAMSCs), including their phenotypic characterization and in vitro potential for differentiation toward osteogenic, adipogenic, and chondrogenic mesodermal lineages.

MATERIALS AND METHODS

Human placentas were obtained from selected caesarean-sectioned births. Two different protocols (Alviano et al. (1) and Soncini et al. (2) ) for the isolation of hAMSCs were performed. After monolayer expansion of adherent cells from both protocols, the cells were characterized by flow cytometry and for multipotentiality, as assessed by their capability to differentiate toward adipocyte-, osteoblast-, and chondrocyte-like cells.

RESULTS

Both protocols yielded hAMSCs that showed plastic adherence, fibroblast-like growth, and well-defined human MSC markers. The cell yield and mesodermal differentiation capability of hAMSCs were higher in cells isolated using the Soncini protocol.

CONCLUSIONS

Our data demonstrated the successful isolation of hAMSCs from full-term placentas using two published protocols. Differences between the two protocols in cell yield and in vitro differentiation potential are shown.

Biological characteristics of stem cells from foetal, cord blood and extraembryonic tissues

Foetal stem cells (FSCs) can be isolated during gestation from many different tissues such as blood, liver and bone marrow as well as from a variety of extraembryonic tissues such as amniotic fluid and placenta. Strong evidence suggests that these cells differ on many biological aspects such as growth kinetics, morphology, immunophenotype, differentiation potential and engraftment capacity in vivo. Despite these differences, FSCs appear to be more primitive and have greater multi-potentiality than their adult counterparts. For example, foetal blood haemopoietic stem cells proliferate more rapidly than those found in cord blood or adult bone marrow. These features have led to FSCs being investigated for pre- and post-natal cell therapy and regenerative medicine applications. The cells have been used in pre-clinical studies to treat a wide range of diseases such as skeletal dysplasia, diaphragmatic hernia and respiratory failure, white matter damage, renal pathologies as well as cancers. Their intermediate state between adult and embryonic stem cells also makes them an ideal candidate for reprogramming to the pluripotent status.

Identification of multipotent cytotrophoblast cells from human first trimester chorionic villi

In this article we used immunohistochemistry and FACS analyses to show that cells expressing markers typical of human stem cells such as SSEA4, OCT-4, ALP, and CD117 are present within the cytotrophoblastic tissue of human fetal chorionic villus samples (CVSs). After immunoselection of CV cells for SSEA4, FACS analyses showed an increased number of cells positive for OCT-4 and ALP and a small percentage (around 4%) of side population (SP) cells. In the same cell population, RT-PCR indicated the presence of OCT-4, NANOG, and SOX2 transcripts, also typical of stem cells. Depending on the in vitro conditions, a subset of SSEA4+ cells formed colonies resembling hESCs, with limited self renewal ability. At the same time, these cells were able to differentiate in vitro into derivatives of all three germ layers. When inoculated into immunocompromised mice, SSEA4+ cells did not form teratomas but were able to populate depleted hematopoietic tissues. Moreover, after injection into mouse blastocysts, they were incorporated into the inner cell mass and could be traced into several tissues of the adult chimeric mice. Finally, we show that SSEA4+ cells isolated from fetuses affected by Spinal Muscular Atrophy (SMA) can be genetically corrected with high efficiency in culture by Small Fragment Homologous Recombination (SFHR), a gene targeting approach. Taken together, our results indicate that SSEA4+ cells obtained from human CVSs contain a subpopulation of multipotent cells that we propose to name Human Cytotrophoblastic-derived Multipotent Cells (hCTMCs). These cells may be a safe and convenient source of cells for cell-based therapy, as well as an ideal target for in utero fetal gene therapy.

Amnion epithelial cell isolation and characterization for clinical use

Human amnion epithelial cells (hAECs) are a heterologous population positive for stem cell markers; they display multilineage differentiation potential, differentiating into cells of the endoderm (liver, lung epithelium), mesoderm (bone, fat), and ectoderm (neural cells). They have a low immunogenic profile and possess potent immunosuppressive properties. Hence, hAECs may be a valuable source of cells for cell therapy. This unit describes an efficient and effective method of hAEC isolation, culture, and cryopreservation that is animal product-free and in accordance with current guidelines on preparation of cells for clinical use. Cells isolated using this method were characterized after 5 passages by analysis of karyotype, cell cycle distribution, and changes in telomere length. The differentiation potential of hAECs isolated using this animal product-free method was demonstrated by differentiation into lineages of the three primary germ layers and expression of lineage-specific markers analyzed by PCR, immunocytochemistry, and histology.