Therapeutic efficiency of human amniotic epithelial stem cell-derived functional hepatocyte-like cells in mice with acute hepatic failure

Human amniotic epithelial stem cell-derived dopaminergic neuron-like cells ameliorate motor dysfunction in a rat model of Parkinson's disease

AIMS

Parkinson's disease (PD) remains a substantial clinical challenge due to the progressive loss of midbrain dopaminergic (DA) neurons in nigrostriatal pathway. In this study, human amniotic epithelial stem cells (hAESCs)-derived dopaminergic neuron-like cells (hAESCs-DNLCs) were generated, with the aim of providing new therapeutic approach to PD.

MATERIALS AND METHODS

hAESCs, which were isolated from discarded placentas, were induced to differentiate into hAESCs-DNLCs by following a "two stages" induction protocol. The differentiation efficiency was assessed by quantitative real-time PCR (qRT-PCR), immunocytochemistry (ICC), and ELISA. Immunogenicity, cell viability and tumorigenicity of hAESCs-DNLC were analyzed before in vivo experiments. Subsequently, hAESCs-DNLCs were transplanted into PD rats, behavioral tests were monitored after graft, and the regeneration of DA neurons was detected by immunohistochemistry (IHC). Furthermore, to trace hAESCs-DNLCs in vivo, cells were pre-labeled with PKH67 green fluorescence.

KEY FINDINGS

hAESCs were positive for pluripotent markers and highly expressed neural stem cells (NSCs) markers. Based on this, we established an induction method reliably generates hAESCs-DNLCs, which was evidenced by epithelium-to-neuron morphological changes, elevated expressions of neuronal and DA neuronal markers, and increased secretion of dopamine. Moreover, hAESCs-DNLCs maintained high cell viability, no tumorigenicity and low immunogenicity, suggesting hAESCs-DNLCs an attractive implant for PD therapy. Transplantation of hAESCs-DNLCs into PD rats significantly ameliorated motor disorders, as well as enhanced the reinnervation of TH+ DA neurons in nigrostriatal pathway.

SIGNIFICANCE

Our study has demonstrated evident therapeutic effects of hAESCs-DNLCs, and provides a safe and promising solution for PD.

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.

Promotion of skin wound healing using hypoimmunogenic epidermal cell sheets

Objective

The physiological process of wound healing is dynamic, continuous, and intricate. Nowadays, full-thickness burn wounds are treated by autologous skin transplantation. Unfortunately, when substantial burns develop, there are fewer donor sites accessible, making it difficult to satisfy the requirement for large-scale skin transplants and increasing the risk of patient mortality. This study investigated the possibility of using a newly created hypoimmunogenic epidermal cell sheet to heal skin wounds.

Methods

Transfection with lentivirus was used to generate Keratinocytes (KCs) that overexpress Indoleamine 2,3-Dioxygenase (IDO). Western blotting and quantitative polymerase chain reaction were used to measure IDO levels. To evaluate the function of IDO+ keratinocytes, CCK-8 and Transwell assays were performed. In cell sheet induction media, KCs and Fibroblasts (FBs) were cultured to yield epidermal cell sheets. The full-thickness skin excisions of BALB/c mice were transplanted with epidermal cell sheets. To assess the tumorigenicity of IDO+ keratinocytes, BALB/c nude mouse xenograft models were also used. CD3 and CD31 immunofluorescence labeling of wound tissue on day 12 to identify T lymphocyte infiltration and capillary development. ELISA measurement of IL-1 and TNF-α concentrations.

Results

IDO + keratinocytes dramatically enhanced the expression levels of IDO mRNA and protein, as well as the amount of kynurenine in the conditioned media of IDO+ keratinocytes, compared to the Control and NC groups. CD8+ T cell apoptosis was considerably greater in the IDO group than in the Control and NC groups. Nevertheless, the proliferation and migratory capabilities of IDO+ keratinocytes were not substantially different from those of the Control and NC groups. In vitro cultivation of the hypoimmunogenic epidermal cell sheet was effective. In vivo transplantation experiments demonstrated that IDO+ epidermal cell sheets can effectively promote wound healing without tumorigenicity, and IDO+ epidermal cell sheets may promote wound healing by decreasing the expression levels of inflammatory factors (TNF and IL-1) in wound tissue, decreasing CD3+ T lymphocytes, and increasing infiltration and new capillaries in wound tissue.

Conclusion

In this study, we successfully constructed the hypoimmunogenic epidermal cell sheet and demonstrated that the hypoimmunogenic epidermal cell sheet could accelerate wound healing.

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.

Amniotic Membrane and Its Derivatives: Novel Therapeutic Modalities in Liver Disorders

The liver is a vital organ responsible for metabolic and digestive functions, protein synthesis, detoxification, and numerous other necessary functions. Various acute, chronic, and neoplastic disorders affect the liver and hamper its biological functions. Most of the untreated liver diseases lead to inflammation and fibrosis which develop into cirrhosis. The human amniotic membrane (hAM), the innermost layer of the fetal placenta, is composed of multiple layers that include growth-factor rich basement membrane, epithelial and mesenchymal stromal cell layers. hAM possesses distinct beneficial anti-fibrotic, anti-inflammatory and pro-regenerative properties via the secretion of multiple potent trophic factors and/or direct differentiation into hepatic cells which place hAM-based therapies as potential therapeutic strategies for the treatment of chronic liver diseases. Decellularized hAM is also an ideal scaffold for liver tissue engineering as this biocompatible niche provides an excellent milieu for cell proliferation and hepatocytic differentiation. Therefore, the current review discusses the therapeutic potential of hAM and its derivatives in providing therapeutic solutions for liver pathologies including acute liver failure, metabolic disorders, liver fibrosis as well as its application in liver tissue engineering.

Cytokine-stimulated human amniotic epithelial cells alleviate DSS-induced colitis in mice through anti-inflammation and regulating Th17/Treg balance

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon characterized by immune dysregulation. Restoration of the balance between regulatory T (Tregs) and T helper 17 (Th17) cells improves UC symptoms. Human amniotic epithelial cells (hAECs) have emerged as a promising therapeutic option for UC because of their immunomodulatory properties. In this study, we aimed to optimize and maximize the therapeutic potential of hAECs by pre-treating them with tumor necrosis factor (TNF)-α and interferon (IFN)-γ (pre-hAECs) for UC treatment. We evaluated the efficacy of hAECs and pre-hAECs in treating dextran sulfate sodium (DSS)-induced colitis mice. Compared to hAECs, pre-hAECs were found to be more effective in alleviating colitis in acute DSS mouse models than in the controls. Additionally, pre-hAEC treatment significantly reduced weight loss, shortened the colon length, decreased the disease activity index, and effectively maintained the recovery of colon epithelial cells. Furthermore, pre-hAEC treatment significantly inhibited the production of pro-inflammatory cytokines, such as interleukin (IL)-1β and TNF-α, and promoted the expression of anti-inflammatory cytokines, such as IL-10. Both in vivo and in vitro studies revealed that pre-treatment with hAECs significantly increased the number of Treg cells, decreased the numbers of Th1, Th2, and Th17 cells, and regulated the balance of Th17/Treg cells. In conclusion, our results revealed that hAECs pre-treated with TNF-α and IFN-γ were highly effective in treating UC, suggesting their potential as therapeutic candidates for UC immunotherapy.

Exosomes Derived from Human Amniotic Mesenchymal Stem Cells Facilitate Diabetic Wound Healing by Angiogenesis and Enrich Multiple lncRNAs

BACKGROUND

Diabetic wound healing remains a major challenge due to the impaired functionality of angiogenesis by persistent hyperglycemia. Mesenchymal stem cell exosomes are appropriate candidates for regulating the formation of angiogenesis in tissue repair and regeneration. Here, we explored the effects of exosomes derived from human amniotic mesenchymal stem cell (hAMSC-Exos) on the biological activities of human umbilical vein endothelial cells (HUVECs) treated with high glucose and on diabetic wound healing and investigate lncRNAs related to angiogenesis in hAMSC-Exos.

METHODS

hAMSCs and hAMSC-Exos were isolated and identified by flow cytometry or western blot. A series of functional assays such as cell counting kit-8, scratching, transwell and tube formation assays were performed to evaluate the potential effect of hAMSC-Exos on high glucose-treated HUVECs. The effect of hAMSC-Exos on diabetic wound healing were tested by measuring wound closure rates and immunohistochemical staining of CD31. Subsequently, the lncRNAs profiles in hAMSC-Exos and hAMSCs were examined to screen the lncRNAs related to angiogenesis.

RESULTS

The isolated hAMSC-Exos had a size range of 30-150 nm and were positive for CD9, CD63 and CD81. The hAMSC-Exos facilitate the functional properties of high glucose-treated HUVECs including the proliferation, migration and the angiogenic activities as well as wound closure and angiogenesis in diabetic wound. hAMSC-Exos were enriched lncRNAs that related to angiogenesis, including PANTR1, H19, OIP5-AS1 and NR2F1-AS1.

CONCLUSION

Our findings demonstrated hAMSC-Exos facilitate diabetic wound healing by angiogenesis and contain several exosomal lncRNAs related to angiogenesis, which may represent a promising strategy for diabetic wound healing.

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.

Amniotic stem cells as a source of regenerative medicine to treat female infertility

Impaired reproductive health is a worldwide problem that affects the psychological well-being of a society. Despite the technological developments to treat infertility, the global infertility rate is increasing significantly. Many infertility conditions are currently treated using various advanced clinical approaches such as intrauterine semination (IUI), in vitro fertilization (IVF), and intracytoplasmic injection (ICSI). Nonetheless, clinical management of some conditions such as dysfunctional endometrium, premature ovarian failure, and ovarian physiological aging still pose significant challenges. Stem cells based therapeutic strategies have a long-standing history to treat many infertility conditions, but ethical restrictions do not allow the broad-scale utilization of adult mesenchymal stromal/stem cells (MSCs). Easily accessible, placental derived or amniotic stem cells present an invaluable alternative source of non-immunogenic and non-tumorigenic stem cells that possess multilineage potential. Given these characteristics, placental or amniotic stem cells (ASCs) have been investigated for therapeutic purposes to address infertility in the last decade. This study aims to summarize the current standing and progress of human amniotic epithelial stem cells (hAECs), amniotic mesenchymal stem cells (hAMSCs), and amniotic fluid stem cells (hAFSCs) in the field of reproductive medicine. The therapeutic potential of these cells to restore or enhance normal ovarian function and pregnancy outcomes are highlighted in this study.

Establishing an hTERT-driven immortalized umbilical cord-derived mesenchymal stem cell line and its therapeutic application in mice with liver failure

Acute liver failure (ALF) is characterized by rapid liver cell destruction. It is a multi-etiological and fulminant complication with a clinical mortality of over 80%. Therapy using mesenchymal stem cells (MSCs) or MSCs-derived exosomes can alleviate acute liver injury, which has been demonstrated in animal experiments and clinical application. However, similar to other stem cells, different cell sources, poor stability, cell senescence and other factors limit the clinical application of MSCs. To achieve mass production and quality control on stem cells and their exosomes, transfecting umbilical cord mesenchymal stem cell (UCMSC) with lentivirus overexpressing human telomerase reverse transcriptase (hTERT) gene, the hTERT-UCMSC was constructed as an immortalized MSC cell line. Compared with the primary UCMSC (P3) and immortalized cell line hTERT-UCMSC at early passage (P10), the hTERT-UCMSC retained the key morphological and physiological characteristics of UCMSC at the 35th passage (P35), and showed no signs of carcinogenicity and toxic effect in mice. There was no difference in either exosome production or characteristics of exosomes among cultures from P3 primary cells, P10 and P35 immortalized hTERT-UCMSCs. Inoculation of either hTERT-UCMSC (P35) or its exosomes improved the survival rate and liver function of ALF mice induced by thioacetamide (TAA). Our findings suggest that this immortalized cell line can maintain its characteristics in long-term culture. Inoculation of hTERT-UCMSC and its exosomes could potentially be used in clinics for the treatment of liver failure in the future.

In Vitro Differentiation of Human Amniotic Epithelial Cells into Hepatocyte-like Cells

Human amniotic epithelial cells (hAECs) represent an interesting clinical alternative to human embryonic (hESCs) and induced pluripotent (hiPSCs) stem cells in regenerative medicine. The potential of hAECs can be enhanced ex vivo by their partial pre-differentiation. The aim of this study was to evaluate the effectiveness of 18-day differentiation of hAECs into endodermal cells, hepatic precursor cells, and cells showing functional features of hepatocytes using culture media supplemented with high (100 ng/mL) concentrations of EGF or HGF. The cells obtained after differentiation showed changes in morphology and increased expression of AFP, ALB, CYP3A4, CYP3A7, and GSTP1 genes. HGF was more effective than EGF in increasing the expression of liver-specific genes in hAECs. However, EGF stimulated the differentiation process more efficiently and yielded more hepatocyte-like cells capable of synthesizing α-fetoprotein during differentiation. Additionally, after 18 days, GST transferases, albumin, and CYP P450s, which proved their partial functionality, were expressed. In summary, HGF and EGF at a dose of 100 ng/mL can be successfully used to obtain hepatocyte-like cells between days 7 and 18 of hAEC differentiation. However, the effectiveness of this process is lower compared with hiPSC differentiation; therefore, optimization of the composition of the medium requires further research.

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.

Effects of Isorhamnetin on Diabetes and Its Associated Complications: A Review of In Vitro and In Vivo Studies and a Post Hoc Transcriptome Analysis of Involved Molecular Pathways

Diabetes mellitus, especially type 2 (T2DM), is a major public health problem globally. DM is characterized by high levels of glycemia and insulinemia due to impaired insulin secretion and insulin sensitivity of the cells, known as insulin resistance. T2DM causes multiple and severe complications such as nephropathy, neuropathy, and retinopathy causing cell oxidative damages in different internal tissues, particularly the pancreas, heart, adipose tissue, liver, and kidneys. Plant extracts and their bioactive phytochemicals are gaining interest as new therapeutic and preventive alternatives for T2DM and its associated complications. In this regard, isorhamnetin, a plant flavonoid, has long been studied for its potential anti-diabetic effects. This review describes its impact on reducing diabetes-related disorders by decreasing glucose levels, ameliorating the oxidative status, alleviating inflammation, and modulating lipid metabolism and adipocyte differentiation by regulating involved signaling pathways reported in the in vitro and in vivo studies. Additionally, we include a post hoc whole-genome transcriptome analysis of biological activities of isorhamnetin using a stem cell-based tool.

Long-term culture of rat hepatocytes using human amniotic membrane as a culture substrate

Amniotic membrane is attracting attention as a new material for regenerative medicine. We herein report that the culture of primary rat hepatocytes on human amniotic membrane maintained their morphology and their production of albumin for at least two months. Human amniotic membrane was collected during planned cesarean section and kept frozen until usage. Primary rat hepatocytes were plated on human amniotic membrane. Hepatocytes accumulated as colonies on amniotic membrane, and their rat albumin level was maintained for two months. Their three-dimensional structure on extracellular matrix, which is abundant in amniotic membranes might influence the maintenance of the hepatocyte-specific function.

•

Long-term primary culture of rat hepatocyte on the human amniotic membrane was successful.

•

Albumin production from primary isolated hepatocytes was maintained for the long term.

•

Amniotic membrane provided the situation of 3D structure for isolated rat hepatocyte.

Downregulation of augmenter of liver regeneration impairs the therapeutic efficacy of liver epithelial progenitor cells against acute liver injury by enhancing mitochondrial fission

Cell-based therapeutic approaches have been proven to be effective strategies for the treatment of acute liver injury (ALI). However, widespread application of these procedures is limited by several key issues, including rapid loss of stemness in vitro, aberrant differentiation into undesirable cell types, and low engraftment in vivo. In this study, liver epithelial progenitor cells (LEPCs) were characterized and transfected with augmenter of liver regeneration (ALR). The results revealed that in ALI mice with CCl₄ , the transplantation of ALR-bearing LEPCs into the liver markedly protected mice against ALI by decreasing the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), thus relieving hepatic tissue injury and attenuating inflammatory infiltration. Mechanistically, the knockdown of ALR in LEPCs activated the phosphorylation of dynamin-related protein 1 (Drp1) at the S616 site and thereby enhanced mitochondrial fission. In contrast, the transfection of ALR into LEPCs significantly inhibited Drp1 phosphorylation, thereby favoring the maintenance of mitochondrial integrity and the preservation of adenosine triphosphate contents in LEPCs. Consequently, the ALR-bearing LEPCs transplanted into ALI mice exhibited substantially greater homing ability to the injured liver via the SDF-1/CXCR4 axis than that of LEPCs-lacking ALR. In conclusion, we demonstrated that the transplantation of ALR-transfected LEPCs protected mice against CCl₄ -induced ALI, thus offering immense curative potential in the clinic.

Treatment of α-1 antitrypsin deficiency using hepatic-specified cells derived from human-induced pluripotent stem cells

OBJECTIVE

α-1 antitrypsin deficiency (AATD) is an inherited liver disease characterized by the "Z" mutations, which can cause pulmonary emphysema and liver fibrosis. Transplantation of the organ (i.e., the lung/liver) is the best treatment method, however, the scarcity of suitable donors limits its application. The cell transplantation technique poses an alternative way of combating liver failure.

METHODS

Hepatic specific differentiation of the human induced pluripotent stem cells (iPSCs) was initiated with 100 ng/mL activin A, followed by 20 ng/mL of BMP-4 and 10 ng/mL of FGF-2. The cells were transplanted into the livers of AATD transgenic mice using intra-splenic injections. FK506 was used as an immunosuppressor. At 1, 3, and 6 months post-transplantation, the human serum albumin (HSA) levels and its DNA contents, and the mice serum and liver tissues were measured using enzyme-linked immunosorbent assays (ELISA), polymerase chain reactions (PCR), and immunohistochemistry to estimate the repopulation of the hepatic-specified cells.

RESULTS

Post transplantation, the hepatic-specified cells were found to be successfully and progressively repopulated in the transgenic mice livers. Additionally, the hepatic-specified cells did not display any carcinogenicity, as confirmed by the absence of any tumors on the animals.

CONCLUSION

We provide a time saving and low cost method of transplanting hepatic-specified cells into the livers of AATD mice without any risk of carcinogenicity, a method that may be a potential option for the treatment of AATD.

Characteristics and Therapeutic Potential of Human Amnion-Derived Stem Cells

Stem cells including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and adult stem cells (ASCs) are able to repair/replace damaged or degenerative tissues and improve functional recovery in experimental model and clinical trials. However, there are still many limitations and unresolved problems regarding stem cell therapy in terms of ethical barriers, immune rejection, tumorigenicity, and cell sources. By reviewing recent literatures and our related works, human amnion-derived stem cells (hADSCs) including human amniotic mesenchymal stem cells (hAMSCs) and human amniotic epithelial stem cells (hAESCs) have shown considerable advantages over other stem cells. In this review, we first described the biological characteristics and advantages of hADSCs, especially for their high pluripotency and immunomodulatory effects. Then, we summarized the therapeutic applications and recent progresses of hADSCs in treating various diseases for preclinical research and clinical trials. In addition, the possible mechanisms and the challenges of hADSCs applications have been also discussed. Finally, we highlighted the properties of hADSCs as a promising source of stem cells for cell therapy and regenerative medicine and pointed out the perspectives for the directions of hADSCs applications clinically.

Global Gene Expression Profiling Reveals Isorhamnetin Induces Hepatic-Lineage Specific Differentiation in Human Amniotic Epithelial Cells

Human amnion epithelial cells (hAECs), derived from discarded term placenta, is anticipated as a new stem cell resource because of their advantages over embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), such as no risk of tumorigenicity and minimal ethical issue. hAECs have been reported to differentiate into hepatic-like cells (HLCs) with variable functionalities suitable for cell-based therapy of end-stage liver diseases, drug screening, and drug toxicity tests. On the other hand, a new research stream has been evolving to use natural compounds as stimulants of stem cell differentiation because of their high availability and minimum side effects. Isorhamnetin is a naturally occurring flavonoid commonly found in fruits and vegetables and has been reported to improve hepatic fibrosis and steatosis. In this present study, we have screened the differentiation potential of isorhamnetin in hAECs. The cells were grown on 3D cell culture and were treated with 20 μM of synthesized isorhamnetin for 10 days without adding any additional growth factors. DNA microarray global gene expression analysis was conducted for differentially expressed genes between isorhamnetin-treated and untreated control cells, gene expression validation was carried out using RT-qPCR method, and finally, several hepatic functions were assessed. Microarray analysis showed that isorhamnetin could activate essential biological processes, molecular functions, and signaling pathways for hepatic differentiation. Hepatic progenitor markers, EPCAM and DLK1, were upregulated in the isorhamnetin-treated hAECs. AFP was downregulated, while ALB was upregulated on Day 10. Furthermore, isorhamnetin-treated cells could show increased CYP enzyme mRNA levels, ICG uptake and release, glycogen storage activity, and urea secretion. Additionally, isorhamnetin-treated cells did not show any trace of transdifferentiation evident by significant downregulation of several colon- and cholangiocyte-specific markers. However, longer treatment with isorhamnetin did not promote hepatic maturation. Altogether, our findings indicate that isorhamnetin has a promising effect on directing the hepatic-lineage specific differentiation in hAECs.

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.

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

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

Effects of Cryogenic Storage on Human Amnion Epithelial Cells

Perinatal stem cells and epithelial cells isolated from full term amnion membrane, in particular, have attracted interest over the last decade, as a promising source of multipotent cells for cellular therapies. Human amnion epithelial cells (hAEC) have been used to treat monogenetic liver disease such as maple syrup urine disease or fibrosis of the liver in preclinical studies. In most studies xeno-transplants of hAEC were conducted without providing immunosuppression to recipients, reflecting the tolerogenic properties of hAEC. For many cell types, successful cryopreservation is critical for providing a readily available, off-the-shelf product. In this study, hAEC were isolated from full-term human placenta from 14 different donors, cryopreserved using a protocol and reagents commonly adopted for epithelial cell preservation. The cells were analyzed in terms of survival, recovery, and homogeneity, profiled for surface markers characteristic of epithelial, mesenchymal, endothelial, or hematopoietic cells. There were no significant differences observed in the percentage of cells with epithelial cell markers before and after cryopreservation. The relative proportion of stromal and hematopoietic cells was significantly reduced in hAEC preparations after cryopreservation. The expression of stem cell and immunomodulatory molecules were confirmed in the final product. Since multipotent cells are readily available from full-term placenta, this novel cell source might significantly increase the number of patients eligible to receive cellular therapies for liver and other diseases.

Perinatal tissues and cells in tissue engineering and regenerative medicine

Perinatal tissues are an abundant source of human extracellular matrix proteins, growth factors and stem cells with proved potential use in a wide range of therapeutic applications. Due to their placental origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Additionally, as a temporary organ, placenta is usually discarded as a medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. Although some of these tissues, such as the amniotic membrane and umbilical cord, have been used in clinical practices, most of them continue to be highly under explored. This review aims to outline the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM), as well as highlight how these solutions can be used to overcome the shortage of adequate scaffolds and cell sources that currently hampers the translation of TERM strategies towards clinical settings. STATEMENT OF SIGNIFICANCE: Stem cells and extracellular matrix derived from perinatal tissues such as placenta and umbilical cord, have drawn great attention for use in a wide variety of applications in the biomedical field. Due to their origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Also they are typically considered medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. This work aims to present and discuss the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM).

Plasma perfusion combined with plasma exchange in chronic hepatitis B-related acute-on-chronic liver failure patients

BACKGROUND AND AIMS

Artificial liver support systems (ALSS) have been shown to significantly reduce mortality in patients with acute-on-chronic liver failure (ACLF). However, the characteristics of patients who would benefit most from ALSS treatment are poorly understood. This study aimed to delineate the indicators for ALSS and evaluate the effectiveness of plasma perfusion combined with plasma exchange (PP + PE) in patients with hepatitis B virus-related ACLF (HBV-ACLF).

METHODS

A total of 898 patients with HBV-ACLF in a single center were enrolled retrospectively. Propensity score matching (PSM) was used in case-paired analysis. Hepatic or extra-hepatic organ failures were defined by Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) criteria. Complications included ascites, infection, hepatopulmonary syndrome, hepatorenal syndrome, hepatic encephalopathy and upper gastrointestinal bleeding. Numbers of organ failures or complications were used for risk stratification.

RESULTS

Among all patients, 418 patients received standard medical therapy (SMT) and 480 received PP + PE plus SMT. After one-to-one paired PSM within the two groups without risk stratification, 293 pairs were enrolled. The PP + PE group displayed significantly lower mortality risk in both 28- and 90-day observation durations. When stratified, patients with two or more organ failures or complications from the PP + PE group showed greater decrease in mortality risk. Moreover, PP + PE treatment significantly increased the resolution of organ failures and complications and ameliorated the development of new organ failures and complications.

CONCLUSIONS

PP + PE treatment significantly reversed organ failures and ameliorated the development of new organ failures and complications, thus reducing mortality risk of patients with HBV-ACLF.

The Bottlenecks in Translating Placenta-Derived Amniotic Epithelial and Mesenchymal Stromal Cells Into the Clinic: Current Discrepancies in Marker Reports

Placenta-derived amniotic cells have prominent features for application in regenerative medicine. However, there are still discrepancies in the characterization of human amniotic epithelial and mesenchymal stromal cells. It seems crucial that the characterization of human amniotic membrane cells be investigated to determine whether there are currently discrepancies in their characterization reports. In addition, possible causes for the witnessed discrepancies need to be addressed toward paving the way for further clinical application and safer practices. The objective of this review is to investigate the marker characterization as well as the potential causes of the discrepancies in the previous reports on placenta-derived amniotic epithelial and mesenchymal stromal cells. The current discrepancies could be potentially due to reasons including passage number and epithelial to mesenchymal transition (EMT), cell heterogeneity, isolation protocols and cross-contamination, the region of cell isolation on placental disk, measuring methods, and gestational age.

Transcriptomic and computational analysis identified LPA metabolism, KLHL14 and KCNE3 as novel regulators of Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is a complex biological program between physiology and pathology. Here, amniotic epithelial cells (AEC) were used as in vitro model of transiently inducible EMT in order to evaluate the transcriptional insights underlying this process. Therefore, RNA-seq was used to identify the differentially expressed genes and enrichment analyses were carried out to assess the intracellular pathways involved. As a result, molecules exclusively expressed in AEC that experienced EMT (GSTA1-1 and GSTM3) or when this process is inhibited (KLHL14 and KCNE3) were identified. Lastly, the network theory was used to obtain a computational model able to recognize putative controller genes involved in the induction and in the prevention of EMT. The results suggested an opposite role of lysophosphatidic acid (LPA) synthesis and degradation enzymes in the regulation of EMT process. In conclusion, these molecules may represent novel EMT regulators and also targets for developing new therapeutic strategies.

Alternative Cell Sources for Liver Parenchyma Repopulation: Where Do We Stand?

Acute and chronic liver failure is a highly prevalent medical condition with high morbidity and mortality. Currently, the therapy is orthotopic liver transplantation. However, in some instances, chiefly in the setting of metabolic diseases, transplantation of individual cells, specifically functional hepatocytes, can be an acceptable alternative. The gold standard for this therapy is the use of primary human hepatocytes, isolated from livers that are not suitable for whole organ transplantations. Unfortunately, primary human hepatocytes are scarcely available, which has led to the evaluation of alternative sources of functional hepatocytes. In this review, we will compare the ability of most of these candidate alternative cell sources to engraft and repopulate the liver of preclinical animal models with the repopulation ability found with primary human hepatocytes. We will discuss the current shortcomings of the different cell types, and some of the next steps that we believe need to be taken to create alternative hepatocyte progeny capable of regenerating the failing liver.

Regulated differentiation of stem cells into an artificial 3D liver as a transplantable source

End-stage liver disease is one of the leading causes of death around the world. Since insufficient sources of transplantable liver and possible immune rejection severely hinder the wide application of conventional liver transplantation therapy, artificial three-dimensional (3D) liver culture and assembly from stem cells have become a new hope for patients with end-stage liver diseases, such as cirrhosis and liver cancer. However, the induced differentiation of single-layer or 3D-structured hepatocytes from stem cells cannot physiologically support essential liver functions due to the lack of formation of blood vessels, immune regulation, storage of vitamins, and other vital hepatic activities. Thus, there is emerging evidence showing that 3D organogenesis of artificial vascularized liver tissue from combined hepatic cell types derived from differentiated stem cells is practical for the treatment of end-stage liver diseases. The optimization of novel biomaterials, such as decellularized matrices and natural macromolecules, also strongly supports the organogenesis of 3D tissue with the desired complex structure. This review summarizes new research updates on novel differentiation protocols of stem cell-derived major hepatic cell types and the application of new supportive biomaterials. Future biological and clinical challenges of this concept are also discussed.

Improved in vivo efficacy of clinical-grade cryopreserved human hepatocytes in mice with acute liver failure

Clinical hepatocyte transplantation short-term efficacy has been demonstrated; however, some major limitations, mainly due to the shortage of organs, the lack of quality of isolated cells and the low cell engraftment after transplantation, should be solved for increasing its efficacy in clinical applications. Cellular stress during isolation causes an unpredictable loss of attachment ability of the cells, which can be aggravated by cryopreservation and thawing. In this work, we focused on the use of a Good Manufacturing Practice (GMP) solution compared with the standard cryopreservation medium, the University of Wisconsin medium, for the purpose of improving the functional quality of cells and their ability to engraft in vivo, with the idea of establishing a biobank of cryopreserved human hepatocytes available for their clinical use. We evaluated not only cell viability but also specific hepatic function indicators of the functional performance of the cells such as attachment efficiency, ureogenic capability, phase I and II enzymes activities and the expression of specific adhesion molecules in vitro. Additionally, we also assessed and compared the in vivo efficacy of human hepatocytes cryopreserved in different media in an animal model of acute liver failure. Human hepatocytes cryopreserved in the new GMP solution offered better in vitro and in vivo functionality compared with those cryopreserved in the standard medium. Overall, the results indicate that the new tested GMP solution maintains better hepatic functions and, most importantly, shows better results in vivo, which could imply an increase in long-term efficacy when used in patients.

Transplanted mouse liver stem cells at different stages of differentiation ameliorate concanavalin A-induced acute liver injury by modulating Tregs and Th17 cells in mice

Acute liver failure (ALF) is a disease with a considerably high mortality rate that still lacks a safe and effective treatment. Transplantation of liver stem cells (LSCs) has been considered to be a promising therapeutic alternative for ALF since LSCs have been shown to be involved in immunomodulation and functional reconstruction of the liver. Our present study evaluated and compared the protective effects of the two mouse LSC lines, YE and R5, as well as those of adult mouse hepatocyte (HC), on concanavalin A (ConA)-induced acute liver injury. YE and R5 cells were analyzed by microscopy, functional assays, and gene expression. We confirmed that YE and R5 cells were undifferentiated cells that had partial hepatocytic functions and a potential to differentiate into hepatocytes. YE cells has characteristics of LSCs at the early stage of differentiation, whereas the differentiation stage of R5 cells was later than that of YE cells. Subsequently, YE, R5, and HC cells were intraperitoneally transplanted into three groups of mice, followed by injection of ConA through the tail vein of each mouse at 12 h later. Blood tests, histology, flow cytometry, and quantitative PCR were then used to evaluate the therapeutic effects of the cell transplantations at 24 h after ConA injections. Compared with that of the ConA control group, YE, R5, and HC cells reduced the expression of alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) in serum and alleviated the degree of hepatic necrosis. Moreover, transplantation of these cells induced more regulatory T cells (Tregs) and less T-helper 17 (Th17) cells in the liver and spleen, and also promoted the expression of forkhead box protein 3 (Foxp3) and interleukin (IL)-10; in contrast, these transplantations induced various degrees of inhibition in the expression of retinoic acid-related orphan receptor γt (RORγt), IL-17A, IL-17F, and tumor necrosis factor-α (TNF-α). The protective effects of YE and R5 cells were significantly stronger than those of HC cells, and YE cells at the earlier differentiation stage than that of R5 cells exhibited the strongest protective effects. These results demonstrate that mouse LSCs at different stages of differentiation alleviate ConA-induced acute liver injury in mice by modulating Tregs, Th17 cells, and cytokine secretion.

Assessment of animal experimental models of toxic liver injury in the context of their potential application as preclinical models for cell therapy

Preclinical animal models allow to study development and progression of several diseases, including liver disorders. These studies, for ethical reasons and medical limits, are impossible to carry out in human patients. At the same time, such experimental models constitute an important source of knowledge on pathomechanisms for drug- and virus-induced hepatotoxicity, both acute and chronic. Carbon tetrachloride, D-Galactosamine, and retrorsine are xenobiotics that can be used in immunocompetent animal models of hepatotoxicity, where chemical-intoxicated livers present histological features representative of human viruses-related infection. A prolonged derangement into liver architecture and functions commonly lead to cirrhosis, eventually resulting in hepatocellular carcinoma. In human, orthotopic liver transplantation commonly resolve most the problems related to cirrhosis. However, the shortage of donors does not allow all the patients in the waiting list to receive an organ on time. A promising alternative treatment for acute and chronic liver disease has been advised in liver cell transplantation, but the limited availability of hepatocytes for clinical approaches, in addition to the immunosuppressant regiment required to sustain cellular long-term engraftment have been encouraging the use of alternative cell sources. A recent effective source of stem cells have been recently identified in the human amnion membrane. Human amnion epithelial cells (hAEC) have been preclinically tested and proven sufficient to rescue immunocompetent rodents lethally intoxicated with drugs. The adoption of therapeutic procedures based on hAEC transplant in immunocompetent recipients affected by liver diseases, as well as patients with immune-related disorders, may constitute a successful new alternative therapy in regenerative medicine.

Human amniotic mesenchymal stem cells and their paracrine factors promote wound healing by inhibiting heat stress-induced skin cell apoptosis and enhancing their proliferation through activating PI3K/AKT signaling pathway

Background

Increasing evidence has shown that mesenchymal stem cells (MSCs) yield a favorable therapeutic benefit for thermal burn skin wounds. Human amniotic MSCs (hAMSCs) derived from amniotic membrane have multilineage differentiation, immunosuppressive, and anti-inflammatory potential which makes them suitable for treating skin wounds. However, the exact effects of hAMSCs on the healing of thermal burn skin wounds and their potential mechanisms are not explored.

Methods

hAMSCs were isolated from amniotic membrane and characterized by RT-PCR, flow cytometry, immunofluorescence, and tumorigenicity test. We assessed the effects of hAMSCs and hAMSC conditional medium (CM) on wound healing in a deep second-degree burn injury model of mice. We then investigated the biological effects of hAMSCs and hAMSC-CM on the apoptosis and proliferation of heat stress-injured human keratinocytes HaCAT and dermal fibroblasts (DFL) both in vivo and in vitro. Next, we explored the underlying mechanisms by assessing PI3K/AKT and GSK3β/β-catenin signaling pathways in heat injured HaCAT and DFL cells after hAMSCs and hAMSC-CM treatments using PI3K inhibitor LY294002 and β-catenin inhibitor ICG001. Antibody array assay was used to identify the cytokines secreted by hAMSCs that may activate PI3K/AKT signaling pathway.

Results

Our results showed that hAMSCs expressed various markers of embryonic stem cells and mesenchymal stem cells and have low immunogenicity and no tumorigenicity. hAMSC and hAMSC-CM transplantation significantly promoted thermal burn wound healing by accelerating re-epithelialization with increased expression of CK19 and PCNA in vivo. hAMSCs and hAMSC-CM markedly inhibited heat stress-induced apoptosis in HaCAT and DFL cells in vitro through activation of PI3K/AKT signaling and promoted their proliferation by activating GSK3β/β-catenin signaling. Furthermore, we demonstrated that hAMSC-mediated activation of GSK3β/β-catenin signaling was dependent on PI3K/AKT signaling pathway. Antibody array assay showed that a panel of cytokines including PAI-1, C-GSF, periostin, and TIMP-1 delivered from hAMSCs may contribute to the improvement of the wound healing through activating PI3K/AKT signaling pathway.

Conclusion

Our results demonstrated that hAMSCs and hAMSC-CM efficiently cure heat stress-induced skin injury by inhibiting apoptosis of skin cells and promoting their proliferation through activating PI3K/AKT signaling pathway, suggesting that hAMSCs and hAMSC-CM may provide an alternative therapeutic approach for the treatment of skin injury.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1366-y) contains supplementary material, which is available to authorized users.

Human Menstrual Blood-Derived Stem Cells Inhibit the Proliferation of HeLa Cells via TGF-β1-Mediated JNK/P21 Signaling Pathways

Human menstrual blood-derived stem cells (hMBSCs) are a novel type of mesenchymal stem cells (MSCs) that have a high proliferative rate, multilineage differentiation potential, low immunogenicity, and low oncogenicity, making them suitable candidates for regenerative medicine. The therapeutic efficacy of hMBSCs has been demonstrated in some diseases; however, their effects on cervical cancer remain unclear. In the present study, we investigated whether hMBSCs have anticancer properties on cervical cancer cells in vivo and in vitro, which has not yet been reported. In vitro, transwell coculturing experiments revealed that hMBSCs suppress the proliferation and invasion of HeLa cervical cancer cells by inducing G0/G1 cell cycle arrest. In vivo, we established a xenografted BALB/c nude mouse model by subcutaneously coinjecting HeLa cells with hMBSCs for 21 days. We found that hMBSCs significantly decrease the average volume and average weight of xenografted tumors. ELISA, TGF-β1 antibody, and recombinant human TGF-β1 (rhTGF-β1) were used to analyze whether TGF-β1 contributed to cell cycle arrest. We found that hMBSC-secreted TGF-β1 and rhTGF-β1 induced cell cycle arrest and increased the expression of phospho-JNK and phospho-P21 in HeLa cells, which was mostly reversed by TGF-β1 antibody. These results indicate that hMBSCs have antitumor properties on cervical cancer in vitro and in vivo, mediated by the TGF-β1/JNK/p21 signaling pathway. In conclusion, this study suggests that hMBSC-based therapy is promising for the treatment of cervical cancer.