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

Optimization of a nanoparticle uptake protocol applied to amniotic-derived cells: unlocking the therapeutic potential

Stem cell-based therapy implementation relies heavily on advancements in cell tracking. The present research has been designed to develop a gold nanorod (AuNR) labeling protocol applied to amniotic epithelial cells (AECs) leveraging the pro-regenerative properties of this placental stem cell source which is widely used for both human and veterinary biomedical regenerative applications, although not yet exploited with tracking technologies. Ovine AECs, in native or induced mesenchymal (mAECs) phenotypes via epithelial-mesenchymal transition (EMT), served as the model. Initially, various uptake methods validated on other sources of mesenchymal stromal cells (MSCs) were assessed on mAECs before optimization for AECs. Furthermore, the protocol was implemented by adopting the biological strategy of MitoCeption to improve endocytosis. The results indicate that the most efficient, affordable, and easy protocol leading to internalization of AuNRs in living mAECs recognized the combination of the one-step uptake condition (cell in suspension), centrifugation-mediated internalization method (G-force) and MitoCeption (mitochondrial isolated from mAECs). This protocol produced labeled vital mAECs within minutes, suitable for preclinical and clinical trials. The optimized protocol has the potential to yield feasible labeled amniotic-derived cells for biomedical purposes: up to 10 million starting from a single amniotic membrane. Similar and even higher efficiency was found when the protocol was applied to ovine and human AECs, thereby demonstrating the transferability of the method to cells of different phenotypes and species-specificity, hence validating its great potential for the development of improved biomedical applications in cell-based therapy and diagnostic imaging.

Human Amniotic Epithelial Stem Cells Alleviate Autoimmune Premature Ovarian Insufficiency in Mice by Targeting Granulosa Cells via AKT/ERK Pathways

Autoimmune factors play an important role in premature ovarian insufficiency (POI). Human amniotic epithelial stem cells (hAESCs) have recently shown promising treatment effects on chemotherapy-induced POI. However, the therapeutic efficacy and underlying mechanisms of hAESCs in autoimmune POI remain to be investigated. In this study, we showed for the first time that intravenous transplantation of hAESCs could reside in the ovary of zona pellucida 3 peptide (pZP3) induced autoimmune POI mice model for at least 4 weeks. hAESCs could improve ovarian function and fertility, alleviate inflammation and reduce apoptosis of granulosa cells (GCs) in autoimmune POI mice. The transcriptome analysis of mice ovaries and in vitro co-cultivation experiments suggest that activation of the AKT and ERK pathways may be the key mechanism in the therapeutic effect of hAESCs. Our work provides the theoretical and experimental foundation for optimizing the administration of hAESCs, as well as the clinical application of hAESCs in autoimmune POI patients.

Exosomes: compositions, biogenesis, and mechanisms in diabetic wound healing

Diabetic wounds are characterized by incomplete healing and delayed healing, resulting in a considerable global health care burden. Exosomes are lipid bilayer structures secreted by nearly all cells and express characteristic conserved proteins and parent cell-associated proteins. Exosomes harbor a diverse range of biologically active macromolecules and small molecules that can act as messengers between different cells, triggering functional changes in recipient cells and thus endowing the ability to cure various diseases, including diabetic wounds. Exosomes accelerate diabetic wound healing by regulating cellular function, inhibiting oxidative stress damage, suppressing the inflammatory response, promoting vascular regeneration, accelerating epithelial regeneration, facilitating collagen remodeling, and reducing scarring. Exosomes from different tissues or cells potentially possess functions of varying levels and can promote wound healing. For example, mesenchymal stem cell-derived exosomes (MSC-exos) have favorable potential in the field of healing due to their superior stability, permeability, biocompatibility, and immunomodulatory properties. Exosomes, which are derived from skin cellular components, can modulate inflammation and promote the regeneration of key skin cells, which in turn promotes skin healing. Therefore, this review mainly emphasizes the roles and mechanisms of exosomes from different sources, represented by MSCs and skin sources, in improving diabetic wound healing. A deeper understanding of therapeutic exosomes will yield promising candidates and perspectives for diabetic wound healing management.

Stem Cells and Acellular Preparations in Bone Regeneration/Fracture Healing: Current Therapies and Future Directions

Bone/fracture healing is a complex process with different steps and four basic tissue layers being affected: cortical bone, periosteum, fascial tissue surrounding the fracture, and bone marrow. Stem cells and their derivatives, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells, skeletal stem cells, and multipotent stem cells, can function to artificially introduce highly regenerative cells into decrepit biological tissues and augment the healing process at the tissue level. Stem cells are molecularly and functionally indistinguishable from standard human tissues. The widespread appeal of stem cell therapy lies in its potential benefits as a therapeutic technology that, if harnessed, can be applied in clinical settings. This review aims to establish the molecular pathophysiology of bone healing and the current stem cell interventions that disrupt or augment the bone healing process and, finally, considers the future direction/therapeutic options related to stem cells and bone healing.

Comparison of the Efficacy of Two Routes of Administration of Human Amniotic Epithelial Cells in Cell Therapy of Acute Hepatic Insufficiency

The route of administration of implanted cells may affect the outcome of cell therapy by directing cell migration to the damaged site. However, the question of the relationship between the route of administration, the efficacy of colonisation of a given organ, and the efficacy of cell therapy has not been resolved. The aim of the study was to localise transplanted intravenously and intraperitoneally human amniotic epithelial cells (hAECs) in the tissues of mice, both healthy and injured, in an animal experimental model of acute liver failure (ALF). Mice intoxicated with D-Galactosamine (D-GalN) at a dose of 150 mg/100 g body weight received D-GalN alone or with a single dose of hAECs administered by different routes. Subsequently, at 6, 24, and 72 h after D-GaIN administration and at 3, 21, and 69 h after hAEC administration, lungs, spleen, liver, and blood were collected from recipient mice. The degree of liver damage and regeneration was assessed based on biochemical blood parameters, histopathological evaluation (H&E staining), and immunodetection of proliferating (Ki67+) and apoptotic (Casp+) cells. The biodistribution of the administered cells was based on immunohistochemistry and the identification of human DNA. It has been shown that after intravenous administration, in both healthy and intoxicated mice, most of the transplanted hAECs were found in the lungs, while after intraperitoneal administration, they were found in the liver. We concluded that a large number of hAECs implanted in the lungs following intravenous administration can exert a therapeutic effect on the damaged liver, while the regenerative effect of intraperitoneally injected hAECs on the liver was very limited due to the relatively lower efficiency of cell engraftment.

Dual cross-linked COL1/HAp bionic gradient scaffolds containing human amniotic mesenchymal stem cells promote rotator cuff tendon-bone interface healing

The tendon-bone interface heals through scar tissue, while the lack of a natural interface gradient structure and collagen fibre alignment leads to the occurrence of retearing. Therefore, the promotion of tendon healing has become the focus of regenerative medicine. The purpose of this study was to develop a gradient COL1/ hydroxyapatite (HAp) biomaterial loaded with human amniotic mesenchymal stem cells (hAMSCs). The performance of common cross-linking agents, Genipin, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS), and dual cross-linked materials were compared to select the best cross-linking mechanism to optimize the biological and mechanical properties of the scaffold. The optimal COL1/HAp-loaded with hAMSCs were implanted into the tendon-bone rotator cuff interfaces in rats and the effect on the tendon-bone healing was assessed by micro-CT, histological analysis, and biomechanical properties. The results showed that Genipin and EDC/NHS dual cross-linked COL1/HAp had good biological activity and mechanical properties and promoted the proliferation and differentiation of hAMSCs. Animal experiments showed that the group using a scaffold loaded with hAMSCs had excellent continuity and orientation of collagen fibers, increased fibrocartilage and bone formation, and significantly higher biomechanical functions than the control group at the interface at 12 weeks post operation. This study demonstrated that dual cross-linked gradient COL1/HAp-loaded hAMSCs could promote interface healing, thereby providing a feasible strategy for tendon-bone interface regeneration.

Therapeutic approaches of cell therapy based on stem cells and terminally differentiated cells: Potential and effectiveness

Cell-based therapy, as a promising regenerative medicine approach, has been a promising and effective strategy to treat or even cure various kinds of diseases and conditions. Generally, two types of cells are used in cell therapy, the first is the stem cell, and the other is a fully differentiated cell. Initially, all cells in the body are derived from stem cells. Based on the capacity, potency and differentiation potential of stem cells, there are four types: totipotent (produces all somatic cells plus perinatal tissues), pluripotent (produces all somatic cells), multipotent (produces many types of cells), and unipotent (produces a particular type of cells). All non-totipotent stem cells can be used for cell therapy, depending on their potency and/or disease state/conditions. Adult fully differentiated cell is another cell type for cell therapy that is isolated from adult tissues or obtained following the differentiation of stem cells. The cells can then be transplanted back into the patient to replace damaged or malfunctioning cells, promote tissue repair, or enhance the targeted organ's overall function. With increasing science and knowledge in biology and medicine, different types of techniques have been developed to obtain efficient cells to use for therapeutic approaches. In this study, the potential and opportunity of use of all cell types, both stem cells and fully differentiated cells, are reviewed.

Hyaluronan delays human amniotic epithelial stem cell senescence by regulating CD44 isoform switch to activate AKT/mTOR signals

The replicative senescence of human amniotic epithelial stem cells (hAECs) is a major concern towards its clinical application. This study found that a 300-kDa hyaluronic acid (HA) could effectively delay the replicative senescence of hAECs, as indicated by the downregulation of cellular senescence markers and alteration of the cell cycle, and substantially improve the differentiation capacities of hAECs. HA was confirmed to regulate the CD44 isoform switch by upregulating the CD44s and downregulating the CD44v, thus exerting an anti-aging effect. We further found that HA induced the upregulation of hyaluronan synthase (HAS) 2, resulting in the activation of epithelial splicing regulatory protein 1 (ESRP1) and alternative splicing of CD44 mRNA, thereby promoting CD44s expression and inhibiting CD44v expression. Knockdown of HAS2 blocked ESRP1 expression and attenuated the anti-aging effects of HA. Hermes-1, a specific blocker of CD44, caused partial loss of the anti-aging effect of HA, upregulated senescence markers, and downregulated stemness markers. Furthermore, CD44s receptor activation was shown to initiate the AKT/mTOR downstream signaling. Conclusively, the study suggested that HA delayed hAEC senescence by regulating CD44 isoform switch to activate the AKT/mTOR signaling pathway, and there is potential for the clinical application of hAECs in combination with HA.

In vitro differentiation of human amniotic epithelial stem cells into keratinocytes regulated by OPN3

Human amniotic epithelial stem cells (hAESCs) are regarded as potential alternatives to keratinocytes (KCs) used for skin wound healing. Light is an alternative approach for inducing stem cell differentiation. Opsins (OPNs), a family of light-sensitive, G protein-coupled receptors, play a multitude of light-dependent and light-independent functions in extraocular tissues. However, it remains unclear whether the light sensitivity and function of OPNs are involved in light-induced differentiation of hAESCs to KCs. Herein, we determine the role of OPNs in differentiation of hAESCs into KCs through cell and molecular biology approaches in vitro. It is shown that mRNA expression of OPN3 in the amniotic membrane and hAESCs was higher than the other four primary OPNs by RT-qPCR analysis. Changes in OPN3 gene expression had a significant impact on cell proliferation, stemness and differentiation capability of hAESCs. Furthermore, we found a significant upregulation of OPN3, KRT5 and KRT14 with hAESCs treated at 3 × 33 J/cm2 irradiation from blue-light LED. Taken together, these results suggest that OPN3 acts as a positive regulator of differentiation of hAESCs into KCs. This study provides a novel insight into photosensitive OPNs associated with photobiomodulation(PBM)-induced differentiation in stem cells.

A 3D-Printed Dual Driving Forces Scaffold with Self-Promoted Cell Absorption for Spinal Cord Injury Repair

Stem cells play critical roles in cell therapies and tissue engineering for nerve repair. However, achieving effective delivery of high cell density remains a challenge. Here, a novel cell delivery platform termed the hyper expansion scaffold (HES) is developed to enable high cell loading. HES facilitated self-promoted and efficient cell absorption via a dual driving force model. In vitro tests revealed that the HES rapidly expanded 80-fold in size upon absorbing 2.6 million human amniotic epithelial stem cells (hAESCs) within 2 min, representing over a 400% increase in loading capacity versus controls. This enhanced uptake benefited from macroscopic swelling forces as well as microscale capillary action. In spinal cord injury (SCI) rats, HES-hAESCs promoted functional recovery and axonal projection by reducing neuroinflammation and improving the neurotrophic microenvironment surrounding the lesions. In summary, the dual driving forces model provides a new rationale for engineering hydrogel scaffolds to facilitate self-promoted cell absorption. The HES platform demonstrates great potential as a powerful and efficient vehicle for delivering high densities of hAESCs to promote clinical treatment and repair of SCI.

Exosomes: Potential key players towards novel therapeutic options in diabetic wounds

Diabetic wounds are usually difficult to heal, and wounds in foot in particular are often aggravated by infection, trauma, diabetic neuropathy, peripheral vascular disease and other factors, resulting in serious foot ulcers. The pathogenesis and clinical manifestations of diabetic wounds are complicated, and there is still a lack of objective and in-depth laboratory diagnosis and classification standards. Exosomes are nanoscale vesicles containing DNA, mRNA, microRNA, cyclic RNA, metabolites, lipids, cytoplasm and cell surface proteins, etc., which are involved in intercellular communication and play a crucial role in vascular regeneration, tissue repair and inflammation regulation in the process of diabetic wound healing. Here, we discussed exosomes of different cellular origins, such as diabetic wound-related fibroblasts (DWAF), adipose stem cells (ASCs), mesenchymal stem cells (MSCs), immune cells, platelets, human amniotic epithelial cells (hAECs), epidermal stem cells (ESCs), and their various molecular components. They exhibit multiple therapeutic effects during diabetic wound healing, including promoting cell proliferation and migration associated with wound healing, regulating macrophage polarization to inhibit inflammatory responses, promoting nerve repair, and promoting vascular renewal and accelerating wound vascularization. In addition, exosomes can be designed to deliver different therapeutic loads and have the ability to deliver them to the desired target. Therefore, exosomes may become an innovative target for precision therapeutics in diabetic wounds. In this review, we summarize the latest research on the role of exosomes in the healing of diabetic wound by regulating the pathogenesis of diabetic wounds, and discuss their potential applications in the precision treatment of diabetic wounds.

MiR-297 inhibits tumour progression of liver cancer by targeting PTBP3

Whereas increasing evidences demonstrate that miR-297 contributes to the tumour development and progression, the role of miR-297 and its underlying molecular mechanisms in hepatocellular carcinoma (HCC) was still unclear. Here, we reported that the expression of miR-297 increased significantly in hepG2 cells after the treatment of the conditioned medium of human amniotic epithelial cells(hAECs) which can inhibit the proliferation and migration of hepG2. And the overexpression of miR-297 inhibits the cell proliferation, migration and invasion of HCC cell lines in vitro and suppressed the tumorigenesis of HCC in vivo. Polypyrimidine tract-binding protein 3 (PTBP3) was identified as a direct target gene of miR-297 in HCC cell lines, and mediated the function of miR-297 in HCC cells. In clinical samples, miR-297 levels have a tendency to decrease, but there are no statistically significant differences. Furthermore, in vitro cell experiments confirmed that overexpression of miR-297 could inhibit the PI3K/AKT signaling pathway by down-regulating PTBP3 expression, thereby inhibiting the proliferation, migration and invasion of HCC cells. In conclusion, our results revealed that miR-297 could down-regulate the expression of PTBP3 and inhibit the activation of PI3K/AKT signaling pathway, thereby preventing HCC growth, migration and invasion.

Transplantation of glutamatergic neuronal precursor cells in the paraventricular thalamus and claustrum facilitates awakening with recovery of consciousness

BACKGROUND

Stem cells offer a promising therapeutic strategy for patients with disorders of consciousness (DOC) after severe traumatic brain injury (TBI), but the optimal transplantation sites and cells are not clear. Although the paraventricular thalamus (PVT) and claustrum (CLA) are associated with consciousness and are candidate transplantation targets, few studies have been designed to investigate this possibility.

METHODS

Controlled cortical injury (CCI) was performed to establish a mouse model of DOC. CCI-DOC paradigm was established to investigate the role of excitatory neurons of PVT and CLA in disorders of consciousness. The role of excitatory neuron transplantation in promoting arousal and recovery of consciousness was determined by optogenetics, chemogenetics, electrophysiology, Western blot, RT-PCR, double immunofluorescence labeling, and neurobehavioral experiments.

RESULTS

After CCI-DOC, neuronal apoptosis was found to be concentrated in the PVT and CLA. Prolonged awaking latency and cognitive decline were also seen after destruction of the PVT and CLA, suggesting that the PVT and CLA may be key nuclei in DOC. Awaking latency and cognitive performance could be altered by inhibiting or activating excitatory neurons, implying that excitatory neurons may play an important role in DOC. Furthermore, we found that the PVT and CLA function differently, with the PVT mainly involved in arousal maintenance while the CLA plays a role mainly in the generation of conscious content. Finally, we found that by transplanting excitatory neuron precursor cells in the PVT and CLA, respectively, we could facilitate awakening with recovery of consciousness, which was mainly manifested by shortened awaking latency, reduced duration of loss of consciousness (LOC), enhanced cognitive ability, enhanced memory, and improved limb sensation.

CONCLUSION

In this study, we found that the deterioration in the level and content of consciousness after TBI was associated with a large reduction in glutamatergic neurons within the PVT and CLA. Transplantation of glutamatergic neuronal precursor cells could play a beneficial role in promoting arousal and recovery of consciousness. Thus, these findings have the potential to provide a favorable basis for promoting awakening and recovery in patients with DOC.

Amniotic Fluid Mesenchymal Stromal Cells Derived from Fetuses with Isolated Cardiac Defects Exhibit Decreased Proliferation and Cardiomyogenic Potential

Amniotic fluid mesenchymal stromal cells (AF-MSCs) represent an autologous cell source to ameliorate congenital heart defects (CHDs) in children. The AF-MSCs, having cardiomyogenic potential and being of fetal origin, may reflect the physiological and pathological changes in the fetal heart during embryogenesis. Hence, the study of defects in the functional properties of these stem cells during fetal heart development will help obtain a better understanding of the cause of neonatal CHDs. Therefore, in the present study, we compared the proliferative and cardiomyogenic potential of AF-MSCs derived from ICHD fetuses (ICHD AF-MSCs) with AF-MSCs from structurally normal fetuses (normal AF-MSCs). Compared to normal AF-MSCs, the ICHD AF-MSCs showed comparable immunophenotypic MSC marker expression and adipogenic and chondrogenic differentiation potential, with decreased proliferation, higher senescence, increased expression of DNA-damaged genes, and osteogenic differentiation potential. Furthermore, the expression of cardiac progenitor markers (PDGFR-α, VEGFR-2, and SSEA-1), cardiac transcription factors (GATA-4, NKx 2-5, ISL-1, TBX-5, TBX-18, and MeF-2C), and cardiovascular markers (cTNT, CD31, and α-SMA) were significantly reduced in ICHD AF-MSCs. Overall, these results suggest that the AF-MSCs of ICHD fetuses have proliferation defects with significantly decreased cardiomyogenic differentiation potential. Thus, these defects in ICHD AF-MSCs highlight that the impaired heart development in ICHD fetuses may be due to defects in the stem cells associated with heart development during embryogenesis.

Human amniotic epithelial stem cells: Hepatic differentiation and regenerative properties in liver disease treatment

The placenta and the extraembryonic tissues represent a valuable source of cells for regenerative medicine. In particular, the amniotic membrane possesses cells with stem cells characteristics that have attracted research attention. Human amniotic epithelial cells (hAECs) have unique and desirable features that position them over other stem cells, not only because of the unlimited potential supplied of, the easy access to placental tissues, and the minimal ethical and legal barriers associated, but also due to the embryonic stem cells markers expression and their ability to differentiate into the three germ layers. In addition, they are non-tumorigenic and have immunomodulatory and anti-inflammatory properties. Hepatic failure is one of the major causes of morbidity and mortality worldwide. Organ transplantation is the best way to treat acute and chronic liver failure, but there are several associated obstacles. Stem cells have been highlighted as alternative hepatocytes source because of their potential for hepatogenic differentiation. HAECs, in particular, have some properties that make them suitable for hepatocyte differentiation. In this work, we review the general characteristics of the epithelial stem cells isolated from human amniotic membrane as well as their ability to differentiate to hepatic cells. We also revise their regenerative properties, with the focus on their potential application in the liver disease treatment.

Microbiota-Associated HAF-EVs Regulate Monocytes by Triggering or Inhibiting Inflammasome Activation

In pregnancy, human amniotic fluid extracellular vesicles (HAF-EVs) exert anti-inflammatory effects on T cells and on monocytes, supporting their immunoregulatory roles. The specific mechanisms are still not completely defined. The aim of this study was to investigate the ability of HAF-EVs, isolated from pregnant women who underwent amniocentesis and purified by gradient ultracentrifugation, to affect inflammasome activation in the human monocytes. Proteomic studies revealed that HAF-EV samples expressed several immunoregulatory molecules as well as small amounts of endotoxin. Surprisingly, metagenomic analysis shows the presence of specific bacterial strain variants associated with HAF-EVs as potential sources of the endotoxin. Remarkably, we showed that a single treatment of THP-1 cells with HAF-EVs triggered inflammasome activation, whereas the same treatment followed by LPS and ATP sensitization prevented inflammasome activation, a pathway resembling monocyte refractories. A bioinformatics analysis of microbiota-HAF-EVs functional pathways confirmed the presence of enzymes for endotoxin biosynthesis as well as others associated with immunoregulatory functions. Overall, these data suggest that HAF-EVs could serve as a source of the isolation of a specific microbiota during early pregnancy. Moreover, HAF-EVs could act as a novel system to balance immune training and tolerance by modulating the inflammasome in monocytes or other cells.

Antiproliferative and apoptotic effects of conditioned medium released from human amniotic epithelial stem cells on breast and cervical cancer cells

INTRODUCTION

Human amniotic membrane (hAM) and its cells have been proposed for several clinical applications, including cancer therapy. However, reports on the anticancer effects of human amniotic epithelial stem cells-conditioned media (hAECs-CM) are limited. This work aims to evaluate the anticancer effects of hAECs-CM on cervical cancer and breast cancer cell lines in vitro.

METHODS

Human term placentas were gained from uncomplicated Cesarean sections from healthy donor women. After amnion peeling from the chorion, its epithelial stem cells were isolated and cultured, and its conditioned medium (CM) was collected for experiments. MTT assay was performed to assess cancer cells viability. Migration rate of cancer cells was examined via wound healing assay. Cell-cycle distribution and apoptosis were determined using flow cytometry.

RESULTS

Based on MTT assay hAECs-CM was cytotoxic against cancerous cell lines in a dose-time-dependent manner. After 48 h of treatment with hAECs-CM pure, the cell viability of breast cancer cells includes MCF-7 and MDA-MB-231 reached to 73.2% and 65.5%, respectively. In the same situation, HeLa cervical cancer cell line revealed the lowest viability by 47.3%. The wound-healing assay displayed an incomplete wound closure of scratched MDA-MB-231 cells and significant inhibition of cell migration after hAECs-CM treatment. The results also revealed that hAECs-CM exerted anti-proliferation activity by prompting cell cycle arrest and apoptosis of cancer cells.Conclusions: hAECs-CM is a potent candidate for inducing apoptosis and simultaneously inhibition of the proliferation and migration of cancer cells via inhibiting cell cycle blockade.

Biological properties and surgical applications of the human amniotic membrane

The amniotic membrane (AM) is the inner part of the placenta. It has been used therapeutically for the last century. The biological proprieties of AM include immunomodulatory, anti-scarring, anti-microbial, pro or anti-angiogenic (surface dependent), and tissue growth promotion. Because of these, AM is a functional tissue for the treatment of different pathologies. The AM is today part of the treatment for various conditions such as wounds, ulcers, burns, adhesions, and skin injury, among others, with surgical resolution. This review focuses on the current surgical areas, including gynecology, plastic surgery, gastrointestinal, traumatology, neurosurgery, and ophthalmology, among others, that use AM as a therapeutic option to increase the success rate of surgical procedures. Currently there are articles describing the mechanisms of action of AM, some therapeutic implications and the use in surgeries of specific surgical areas, this prevents knowing the therapeutic response of AM when used in surgeries of different organs or tissues. Therefore, we described the use of AM in various surgical specialties along with the mechanisms of action, helping to improve the understanding of the therapeutic targets and achieving an adequate perspective of the surgical utility of AM with a particular emphasis on regenerative medicine.

Therapeutic Effect of Biomimetic Scaffold Loaded with Human Amniotic Epithelial Cell-Derived Neural-like Cells for Spinal Cord Injury

Spinal cord injury (SCI) results in devastating consequences for the motor and sensory function of patients due to neuronal loss and disrupted neural circuits, confronting poor prognosis and lack of effective therapies. A new therapeutic strategy is urgently required. Here, human amniotic epithelial cells (hAEC), featured with immunocompatibility, non-tumorgenicity and no ethical issues, were induced into neural-like cells by a compound cocktail, as evidenced with morphological change and the expression of neural cell markers. Interestingly, the hAEC-neural-like cells maintain the characteristic of low immunogenicity as hAEC. Aiming at SCI treatment in vivo, we constructed a 3D-printed GelMA hydrogel biomimetic spinal cord scaffold with micro-channels, in which hAEC-neural-like cells were well-induced and grown. In a rat full transection SCI model, hAEC-neural-like cell scaffolds that were implanted in the lesion demonstrated significant therapeutic effects; the neural circuit and hindlimb locomotion were partly recovered compared to little affection in the SCI rats receiving an empty scaffold or a sham implantation operation. Thus, the establishment of hAEC-neural-like cell biomimetic scaffolds may provide a safe and effective treatment strategy for SCI.

Stem cells: a comprehensive review of origins and emerging clinical roles in medical practice

Stem cells are types of cells that have unique ability to self-renew and to differentiate into more than one cell lineage. They are considered building blocks of tissues and organs. Over recent decades, they have been studied and utilized for repair and regenerative medicine. One way to classify these cells is based on their differentiation capacity. Totipotent stem cells can give rise to any cell of an embryo but also to extra-embryonic tissue as well. Pluripotent stem cells are limited to any of the three embryonic germ layers; however, they cannot differentiate into extra-embryonic tissue. Multipotent stem cells can only differentiate into one germ line tissue. Oligopotent and unipotent stem cells are seen in adult organ tissues that have committed to a cell lineage. Another way to differentiate these cells is based on their origins. Stem cells can be extracted from different sources, including bone marrow, amniotic cells, adipose tissue, umbilical cord, and placental tissue. Stem cells began their role in modern regenerative medicine in the 1950's with the first bone marrow transplantation occurring in 1956. Stem cell therapies are at present indicated for a range of clinical conditions beyond traditional origins to treat genetic blood diseases and have seen substantial success. In this regard, emerging use for stem cells is their potential to treat pain states and neurodegenerative diseases such as Parkinson's and Alzheimer's disease. Stem cells offer hope in neurodegeneration to replace neurons damaged during certain disease states. This review compares stem cells arising from these different sources of origin and include clinical roles for stem cells in modern medical practice.

Amniotic Fluid and Placental Membranes as Sources of Stem Cells: Progress and Challenges

The intention of this special edition is to collect review and original research articles that illustrate and stimulate growing efforts to understand the implication of perinatal stem cells in pathological conditions such as cardiovascular and metabolic diseases and inflammatory, autoimmune, musculoskeletal, and degenerative diseases [...].

A Survey and Critical Evaluation of Isolation, Culture, and Cryopreservation Methods of Human Amniotic Epithelial Cells

Human amniotic epithelial cells (hAECs), derived from an epithelial cell layer of the human amniotic membrane, possess embryonic stem-like properties and are known to maintain multilineage differentiation potential. Unfortunately, an inability to expand hAECs without significantly compromising their stem cell potency has precluded their widespread use for regenerative therapies. This article critically evaluates the methods used for isolation, expansion, and cryopreservation of hAECs. We assessed the impact of these methods on ex-vivo expansion and stem cell phenotype of hAECs. Moreover, the progress and challenges to optimize clinically suitable culture conditions for an efficient ex-vivo expansion and storage of these cells are highlighted. Additionally, we also reviewed the currently used hAECs isolation and characterization methods employed in clinical trials. Despite the developments made in the last decade, significant challenges still exist to overcome limitations of ex-vivo expansion and retention of stemness of hAECs in both xenogeneic and xenofree culture conditions. Therefore, optimization and standardization of culture conditions for robust ex-vivo maintenance of hAECs without affecting tissue regenerative properties is an absolute requirement for their successful therapeutic manipulation. This review may help the researchers to optimize the methods that support ex-vivo survival, proliferation, and self-renewal properties of the hAECs.Abbreviations: AM: Human amniotic membrane; CM-HBSS: Ca⁺⁺ and Mg⁺⁺ free HBSS; DMEM: Dulbecco's Modified Eagle Medium; DMEM-HG: DMEM-high glucose; EMEM: Eagle's Modified Essential Medium; EMT: Epithelial-to-mesenchymal transition; EpM: Epi-life complete media; ESC: Embryonic stem cells; ESCM: Epithelial cell surface markers; hAECs: Human amniotic epithelial cells; HLA: Human leukocyte antigen; IM: Immunogenicity markers; iPSC: Induced pluripotent stem cells; KOSR; KSR: Knockout serum replacement; KSI: Key success indicators; CHM: Cell heterogeneity markers; Nanog: NANOG homeobox; Oct-4: Octamer binding transcription factor 4; OR: Operation room; P: Passage; PM: Pluripotency markers; SCM: Stem cell markers for non-differentiated cells; Sox-2: Sry-related HMG box gene 2; SSEA-4: Stage-specific embryonic antigen; TRA: Tumor rejection antigen; UC: Ultra-culture; XF: Xenogeneic free.

Electrospun Polycaprolactone (PCL)-Amnion Nanofibrous Membrane Promotes Nerve Regeneration and Prevents Fibrosis in a Rat Sciatic Nerve Transection Model

Functional recovery after peripheral nerve injury repair is typically unsatisfactory. An anastomotically poor microenvironment and scarring at the repair site are important factors impeding nerve regeneration. In this study, an electrospun poly-e-caprolactone (PCL)-amnion nanofibrous membrane comprising an amnion membrane and nonwoven electrospun PCL was used to wrap the sciatic nerve repair site in the rat model of a sciatic nerve transection. The effect of the PCL-amnion nanofibrous membrane on improving nerve regeneration and preventing scarring at the repair site was evaluated by expression of the inflammatory cytokine, sciatic functional index (SFI), electrophysiology, and histological analyses. Four weeks after repair, the degree of nerve adhesion, collagen deposition, and intraneural macrophage invasion of the PCL-amnion nanofibrous membrane group were significantly decreased compared with those of the Control group. Moreover, the PCL-amnion nanofibrous membrane decreased the expression of pro-inflammatory cytokines such as interleukin(IL)-6, Tumor Necrosis Factor(TNF)-a and the number of pro-inflammatory M1 macrophages, and increased the expression of anti-inflammatory cytokine such as IL-10, IL-13 and anti-inflammatory M2 macrophages. At 16 weeks, the PCL-amnion nanofibrous membrane improved functional recovery, including promoting nerve Schwann cell proliferation, axon regeneration, and reducing the time of muscle denervation. In summary, the PCL-amnion nanofibrous membrane effectively improved nerve regeneration and prevent fibrosis after nerve repair, which has good clinical application prospect for tissue repair.

Update of application of olfactory ensheathing cells and stem cells/exosomes in the treatment of retinal disorders

Age-related macular degeneration, diabetic retinopathy, retinitis pigmentosa and other retinal disorders are the main causes of visual impairment worldwide. In the past, these retinal diseases, especially dry age-related macular degeneration, proliferative diabetic retinopathy and retinitis pigmentosa, were treated with traditional surgery and drugs. However, the effect was moderate. In recent years, researchers have used embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, olfactory ensheathing cells and other stem cells to conduct experiments and found that stem cells can inhibit inflammation, regulate immune response, secrete neurotrophic factors, and differentiate into retinal cells to replace and promote restoration of the damaged parts. These stem cells have the potential to treat retinal diseases. Whether it is in animal experiments or clinical trials, the increase in the number of retinal cells, maintenance of function and improvement of visual function all reflect the advanced of stem cells to treat retinal diseases, but its risk preserves the donor's hidden pathogenic genes, immune rejection and tumorigenicity. With the development of exosomes study, researchers have discovered that exosomes come from a wide range of sources and can be secreted by almost all types of cells. Using exosomes with stem cell to treat retinal diseases is more effective than using stem cells alone. This review article summarizes the recent advances in the application of olfactory ensheathing cells and stem cells/exosomes in the treatment of retinal disorders.

Gene Expression in Amnion-Derived Cells Cultured on Recombinant Laminin 332-A Preliminary Study

Human amniotic cells (hAC) exhibit characteristics of undifferentiated cells and immunomodulatory properties. Recognition of the relationship between amniotic cells and components of the extracellular matrix is an important condition for their ex vivo preparation and further successful clinical application in regenerative medicine and transplantology. Laminin 332 (LN-332), as a natural component of the basement membrane of amniotic epithelial cells and a ligand for integrin receptors, may strongly influence the phenotype and fate of amniotic cells. We investigated the impact of recombinant LN-332 on hAC viability and expression of markers for pluripotency, early differentiation, adhesion, and immunomodulatory properties. During 14 days of culture, hAC were quantified and qualified by light microscopy, immunohistochemistry, immunocytochemistry, and flow cytometry. Gene expression was assessed with real-time polymerase chain reaction (RT-PCR) arrays and compared with differentiated cells originated from the three germ layers. LN-332 caused an over 2-fold increase in the total number of hAC, accompanied by a 75% reduction of SSEA-4-positive cells and an increase in HLA-ABC-positive cells. In particular, we observed that the presence of laminin 332 in the medium of a short-time culture modifies the effect of culture duration on hAC, enhancing time-dependent inhibition of expression of certain genes, including pluripotency and differentiation markers, laminin 332 subunits (which may be part of self-regulation of LN-332 synthesis by amniotic cells), and integrins. The changes observed in hAC were more distinct with respect to differentiated mesenchymal cells, resulting in more comparable phenotypes than those represented by differentiated endo- and ectodermal cells. We concluded that laminin 332 present in the culture medium influences to a certain extent proliferation, adhesion, and differentiation of amniotic cells in culture.

Bioengineering human placentas: social implications of an advancing field

Technological advances in bioengineering, especially in microphysiological systems and organoids, are changing the way in which placental tissue is used and perceived. These advances raise important questions surrounding consent, privacy, biobanking, and research ethics. We explore emerging technologies which use placental tissue and the pressing associated bioethical concerns they raise.

Crescentic Glomerulonephritis: Pathogenesis and Therapeutic Potential of Human Amniotic Stem Cells

Chronic kidney disease (CKD) leads to significant morbidity and mortality worldwide. Glomerulonephritis (GN) is the second leading cause of CKD resulting in end stage renal failure. The most severe and rapidly progressive type of GN is characterized by glomerular crescent formation. The current therapies for crescentic GN, which consist of broad immunosuppressive drugs, are partially effective, non-specific, toxic and cause many serious side effects including infections, cancer, and cardiovascular problems. Therefore, new and safer therapies are needed. Human amniotic epithelial cells (hAECs) are a type of stem cell which are isolated from the placenta after birth. They represent an attractive and novel therapeutic option for the treatment of various inflammatory conditions owing to their unique and selective immunosuppressive ability, as well as their excellent safety profile and clinical applicability. In this review, we will discuss the immunopathogenesis of crescentic GN, issues with currently available treatments and how hAECs offer potential to become a new and harmless treatment option for this condition.

The Synergistic Anti-Apoptosis Effects of Amniotic Epithelial Stem Cell Conditioned Medium and Ponesimod on the Oligodendrocyte Cells

Multiple sclerosis is a chronic inflammatory and neurodegenerative disease of the central nervous system. The current treatment of Multiple sclerosis is based on anti-inflammatory disease-modifying treatments, which can not regenerate myelin and eventually neurons. So, we need new approaches for axonal protection and remyelination. Amniotic epithelial stem cells amniotic epithelial cells, as a neuroprotective and neurogenic agent, are a proper source in tissue engineering and regenerative medicine. Due to differentiation capability and secretion of growth factors, AECs can be a candidate for the treatment of MS. Moreover, sphingosine-1-phosphate (S1P) receptor modulators were recently approved by FDA for MS. Ponesimod is an S1P receptor-1 modulator that acts selectively as an anti-inflammatory agent and provides a suitable microenvironment for the function of the other neuroprotective agents. In this study, due to the characteristics of AECs, they are considered a treatment option in MS. The conditioned medium of AECs concurrently with ponesimod was used to evaluate the viability of the oligodendrocyte cell line after induction of cell death by cuprizone. Cell viability after treatment by conditioned medium and ponesimod was increased compared to untreated groups. Also, the results showed that combination therapy with CM and ponesimod had a synergistic anti-apoptotic effect on oligodendrocyte cells. The combination treatment with CM and ponesimod reduced the expression of caspase-3, caspase-8, Bax, and Annexin V proteins and increased the relative BCL-2/Bax ratio, indicating inhibition of apoptosis as a possible mechanism of action. Based on these promising results, combination therapy with amniotic stem cells and ponesimode could be a proper alternative for multiple sclerosis treatment.

Stem Cells: A Historical Review about Biological, Religious, and Ethical Issues

Stem cells can be used to replace damaged cells or regenerate organs and have broadened our knowledge of the development and progression of certain diseases. Despite significant advances in understanding stem cell biology, several problems limit their use. These problems are related not only to the growth of tumors in animal models and their rejection in transplant cases but also to ethical and social issues about the use of embryonic cells. The ethical-scientific debate on this type of cells has taken on great interest both for their application in regenerative medicine and for the potential possibilities in the field of cell and gene therapy. Different points of view often have the expression of a perception that depends on scientific goals or opportunities or on religious traditions and beliefs. Therefore, as the questions and doubts about when life begins, so do the answers for the use of these cells as therapy or otherwise. So, in addition to the origin of stem cells, there are currently some social bioethical (such as political and legislative issues) and religious dilemmas. The purpose of the study is aimed at being a narrative on the history of stem cells and the evolution of their use to date, as well as to clarify the bioethical position of the various religions today in comparison with the social ones regarding the research and use of embryonic and adult ones. Hence, their biological hypostasis regarding the concepts of “conception” and “fertilization” and their development and therapeutic use compared to those of the main theological doctrines.