Conditioned medium from human amniotic epithelial cells may induce the differentiation of human umbilical cord blood mesenchymal stem cells into dopaminergic neuron-like cells

Hypoxic preconditioning promotes the immunosuppressive effects of mesenchymal stem cells in mice with colitis

Mesenchymal stem cells are promising candidates for stem cell therapy in many diseases, especially in immune-associated diseases. Inflammatory bowel disease is a chronic autoimmune disease that can lead to colorectal cancer if it is not controlled. Mesenchymal stem cells are always under a hypoxic environment in vivo, whether in bone marrow or adipose tissue, whereas researchers always culture MSCs (mesenchymal stem cells) under normoxic conditions (21%). In this study, we aimed to investigate whether hypoxia (1%) affects the therapeutic effect of MSCs. We hypothesize that hypoxia may benefit the treatment efficacy of MSCs. We used DSS to induce IBD (inflammatory bowel disease) in mice and then injected MSCs that had been preconditioned under normoxic conditions (21%) and hypoxic conditions (1%). We found that compared with normoxic-preconditioned MSCs (n-MSCs), hypoxic-preconditioned MSCs (h-MSCs) could alleviate colon inflammation to a large extent, as determined by inflammatory cytokines and CD3+ T cell activation. Mechanistic studies showed that hypoxia could promote iNOS expression in MSCs. Therefore, our data suggest that hypoxia may be more appropriate than normoxia for facilitating MSCs exertion of therapeutic functions.

Human placenta-derived amniotic epithelial cells as a new therapeutic hope for COVID-19-associated acute respiratory distress syndrome (ARDS) and systemic inflammation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has become in the spotlight regarding the serious early and late complications, including acute respiratory distress syndrome (ARDS), systemic inflammation, multi-organ failure and death. Although many preventive and therapeutic approaches have been suggested for ameliorating complications of COVID-19, emerging new resistant viral variants has called the efficacy of current therapeutic approaches into question. Besides, recent reports on the late and chronic complications of COVID-19, including organ fibrosis, emphasize a need for a multi-aspect therapeutic method that could control various COVID-19 consequences. Human amniotic epithelial cells (hAECs), a group of placenta-derived amniotic membrane resident stem cells, possess considerable therapeutic features that bring them up as a proposed therapeutic option for COVID-19. These cells display immunomodulatory effects in different organs that could reduce the adverse consequences of immune system hyper-reaction against SARS-CoV-2. Besides, hAECs would participate in alveolar fluid clearance, renin–angiotensin–aldosterone system regulation, and regeneration of damaged organs. hAECs could also prevent thrombotic events, which is a serious complication of COVID-19. This review focuses on the proposed early and late therapeutic mechanisms of hAECs and their exosomes to the injured organs. It also discusses the possible application of preconditioned and genetically modified hAECs as well as their promising role as a drug delivery system in COVID-19. Moreover, the recent advances in the pre-clinical and clinical application of hAECs and their exosomes as an optimistic therapeutic hope in COVID-19 have been reviewed.

Human Amniotic Epithelial Cells Secretome: Components, Bioactivity, and Challenges

Human amniotic epithelial cells (hAECs) derived from placental tissue have received significant attention as a promising tool in regenerative medicine. Several studies demonstrated their anti-inflammatory, anti-fibrotic, and tissue repair potentials. These effects were further shown to be retained in the conditioned medium of hAECs, suggesting their paracrine nature. The concept of utilizing the hAEC-secretome has thus evolved as a therapeutic cell-free option. In this article, we review the different components and constituents of hAEC-secretome and their influence as demonstrated through experimental studies in the current literature. Studies examining the effects of conditioned medium, exosomes, and micro-RNA (miRNA) derived from hAECs are included in this review. The challenges facing the application of this cell-free approach will also be discussed based on the current evidence.

Therapeutic uses of post-partum tissue-derived mesenchymal stromal cell secretome

Human post-partum tissue mesenchymal stromal cells (hPPT-MSCs) are widely used in research to investigate their differentiation capabilities and therapeutic effects as potential agents in cell-based therapy. This is ascribed to the advantages offered by the use of MSCs isolated from hPPT over other MSC sources. A paradigm shift in related research is evident that focuses on the secretome of the human MSCs (hMSCs), as therapeutic effects of hMSCs are attributed more so to their secreted growth factors, cytokines and chemokines and to the extracellular vesicles (EVs), all of which are components of the hMSC secretome. Positive therapeutic effects of the hPPT-MSC secretome have been demonstrated in diseases related to skin, kidney, heart, nervous system, cartilage and bones, that have aided fast recovery by replacing damaged, non-functional tissues, via differentiating and regenerating cells. Although certain limitations such as short half -life of the secretome components and irregular secreting patterns exist in secretome therapy, these issues are successfully addressed with the use of cutting-edge technologies such as genome editing and recombinant cytokine treatment. If the current limitations can be successfully overcome, the hPPT-MSC secretome including its EVs may be developed into a cost-effective therapeutic agent amenable to be used against a wide range of diseases/disorders.

Regulation of BDNF-TrkB Signaling and Potential Therapeutic Strategies for Parkinson's Disease

Brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin-related kinase receptor type B (TrkB) are widely distributed in multiple regions of the human brain. Specifically, BDNF/TrkB is highly expressed and activated in the dopaminergic neurons of the substantia nigra and plays a critical role in neurophysiological processes, including neuro-protection and maturation and maintenance of neurons. The activation as well as dysfunction of the BDNF-TrkB pathway are associated with neurodegenerative diseases. The expression of BDNF/TrkB in the substantia nigra is significantly reduced in Parkinson's Disease (PD) patients. This review summarizes recent progress in the understanding of the cellular and molecular roles of BNDF/TrkB signaling and its isoform, TrkB.T1, in Parkinson's disease. We have also discussed the effects of current therapies on BDNF/TrkB signaling in Parkinson's disease patients and the mechanisms underlying the mutation-mediated acquisition of resistance to therapies for Parkinson's disease.

Proliferation and odontogenic differentiation of human umbilical cord mesenchymal stem cells and human dental pulp cells co-cultured in hydrogel

OBJECTIVE

The aim of this study was to evaluate the proliferation and odontogenic differentiation of human dental pulp cells (hDPCs) and human umbilical cord mesenchymal stem cells (hUCMSCs) in three-dimensional co-culture system which was established with the help of bone morphogenetic protein-2 (BMP-2) and hydrogel.

METHODS

hDPCs and hUCMSCs were cultured in different concentrations of hydrogel to explore the more suitable concentrations for subsequent experiments. hUCMSCs and hDPCs induced by BMP-2 were co-cultured in the hydrogel. MTT assay was used to measure the cell viability. The differentiation into odontoblast-like cells were measured by the mRNA expression of dentin salivary phosphoprotein (DSPP), dentin matrix protein-1 (DMP-1), alkaline phosphatase and osteocalcin. Alizarin red staining was performed for the formation of mineralized nodules.

RESULTS

hUCMSCs and hDPCs could grow and proliferate in hydrogel scaffold. The growth rate of cells in lower concentrations hydrogels were higher than that of high concentrations hydrogels (P < 0.05). The study showed that 0.25% hydrogel scaffold was more suitable for subsequent experiments than other groups. Compared with hUCMSCs-monoculture and hDPCs-monoculture, the co-culture groups exhibited more proliferative potential, alkaline phosphatase activity and mineralization nodule formation (P < 0.05). The mRNA expression in co-culture groups were higher than that of hUCMSCs-monoculture, closed to or even higher than that of hDPCs-monoculture.

CONCLUSION

0.25% hydrogel was the suitable concentration in co-culture system for subsequent experiments. The co-culture groups had stronger abilities of odontoblastic differentiation and mineralization than cells-monoculture groups, indicated that the co-culture conditions could regulate cell proliferation and differentiation within a certain range.

Human amniotic epithelial cell transplantation promotes neurogenesis and ameliorates social deficits in BTBR mice

Background

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in social interactions and communication and stereotypical patterns of behaviors, interests, or activities. Even with the increased prevalence of ASD, there is no defined standard drug treatment for ASD patients. Currently, stem cells, including human amniotic epithelial cell (hAEC) transplantation, seem to be a promising treatment for ASD, but the effectiveness needs to be verified, and the mechanism has not been clarified.

Methods

We intraventricularly transplanted hAECs into a 2-month-old BTBR T+tf/J (BTBR) mouse model of ASD. Behavior tests were detected 1 month later; hippocampal neurogenesis, neuroprogenitor cell (NPC) pool, and microglia activation were analyzed with immunohistochemistry and immunofluorescence; the levels of pro-inflammatory cytokines, brain-derived neurotrophic factor (BDNF), and TrkB in the hippocampus were determined by real-time PCR or western blotting.

Results

After intraventricular injection of hAECs into adult males, social deficits in BTBR mice were significantly ameliorated. In addition, hAEC transplantation restored the decline of neurogenesis and NPCs in the hippocampus of BTBR mice by expanding the stem cell pool, and the decreased levels of BDNF and TrkB were also rescued in the hippocampus of the hAEC-injected BTBR mice. Meanwhile, the transplantation of hAECs did not induce microglial overactivation or excessive production of pro-inflammatory cytokines in the hippocampus of BTBR mice.

Conclusions

Based on these results, we found that hAEC transplantation ameliorated social deficits and promoted hippocampal neurogenesis in BTBR mice. Our study indicates a promising therapeutic option that could be applied to ASD patients in the future.

Mesenchymal stem cells overexpressing hepatocyte nuclear factor-4 alpha alleviate liver injury by modulating anti-inflammatory functions in mice

Background

Mesenchymal stem cells (MSCs) can migrate to tissue injury sites where they can induce multipotential differentiation and anti-inflammation effects to treat tissue injury. When traditional therapeutic methods do not work, MSCs are considered to be one of the best candidates for cell therapy. MSCs have been used for treating several injury- and inflammation-associated diseases, including liver cirrhosis. However, the therapeutic effect of MSCs is limited. In some cases, the anti-inflammatory function of naïve MSCs is not enough to rescue tissue injury.

Methods

Carbon tetrachloride (CCl₄) was used to establish a mouse liver cirrhosis model. Enhanced green fluorescence protein (EGFP) and hepatocyte nuclear factor-4α (HNF-4α) overexpression adenoviruses were used to modify MSCs. Three weeks after liver injury induction, mice were injected with bone marrow MSCs via their tail vein. The mice were then sacrificed 3 weeks after MSC injection. Liver injury was evaluated by measuring glutamic-pyruvic transaminase (ALT) and glutamic oxalacetic transaminase (AST) levels. Histological and molecular evaluations were performed to study the mechanisms.

Results

We found that HNF-4α-overexpressing MSCs had a better treatment effect than unmodified MSCs on liver cirrhosis. In the CCl₄-induced mouse liver injury model, we found that HNF-4α-MSCs reduced inflammation in the liver and alleviated liver injury. In addition, we found that HNF-4α promoted the anti-inflammatory effect of MSCs by enhancing nitric oxide synthase (iNOS) expression, which was dependent on the nuclear factor kappa B (NF-κB) signalling pathway.

Conclusions

MSCs overexpressing HNF-4α exerted good therapeutic effects against mouse liver cirrhosis due to an enhanced anti-inflammatory effect. Gene modification is likely a promising method for improving the effects of cell therapy.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1260-7) contains supplementary material, which is available to authorized users.

Differentiation of adult human mesenchymal stem cells into dopaminergic neurons

The striatal dopamine (DA) deficiency is known as the main cause of the clinical picture of Parkinson’s disease (PD). The disease is a progressive degeneration of dopaminergic neurons in the striatum. The treatment of PD is based on compensation for the brain’s supply of DA lost by drug therapy, deep brain stimulation, surgery, gene and cell therapies. Clinical studies have focused on the utility of stem cell-based therapies in PD. Embryonic and mesenchymal stem cells (MSCs) are widely used. Recently, human adipose derived stem cells (hADSCs) have been considered as a suitable source of tissue for this purpose. In this project, hADSCs differentiated into dopaminergic neurons and the specificity of the cell preparations was examined. Human adipose tissues were collected from healthy volunteers undergoing liposuction and hADSCs were isolated by collagenase-based enzymatic method. Flow cytometry was performed using the surface cluster of differentiation (CD) markers to confirm the cell typical properties. Then hADSCs were differentiated to dopaminergic neurons in neurobasal medium in the presence of differentiation factors and confirmed by immunocytochemistry via neuronal and dopaminergic markers. The isolated hADSCs were cultured and identified by the expression of MSCs surface markers including CD90, and CD44. These cells did not express hematopoietic surface markers such as CD45 and CD14. Differentiated cells express neuronal marker NeuN and dopaminergic marker tyrosine hydroxylase (TH). It is concluded that hADSCs can be easily taken from the patient’s own body and differentiated into dopaminergic cells having a lower risk of transplant rejection.

Efficient generation of functional cardiomyocytes from human umbilical cord-derived virus-free induced pluripotent stem cells

We have previously demonstrated that human umbilical cord-derived mesenchymal stem cells (UC-MSCs) can differentiate into cardiomyocyte-like cells. However, no contracting cells were observed during differentiation. In this study, we generated induced pluripotent stem cells (iPSCs) from UC-MSCs using mRNA reprogramming and focused on the differentiation of reprogrammed iPSCs into functional cardiomyocytes. For cardiac differentiation, the spontaneously contracting cell clusters were present on day 8 of differentiation. Immunostaining studies and cardiac-specific gene expression confirmed the cardiomyocyte phenotype of the differentiated cells. Electrophysiology studies indicated that iPSCs derived from UC-MSCs had a capacity for differentiation into nodal-, atrial-, and ventricular-like phenotypes based on action potential characteristics, and the derived cardiomyocytes exhibited responsiveness to β-adrenergic and muscarinic stimulations. Moreover, the derived cardiomyocytes displayed spontaneous intracellular Ca²⁺ transients. These results demonstrate that functional cardiomyocytes can be generated from reprogrammed UC-MSCs, and the methodology described here will serve as a useful protocol to obtain functional cardiomyocytes from human mesenchymal stem cells.

Effect of co‑culture with amniotic epithelial cells on the biological characteristics of amniotic mesenchymal stem cells

The aim of the present study was to investigate the effect of co‑culture with amniotic epithelial cells (AECs) on the biological characteristics of amniotic mesenchymal stem cells (AMSCs), to compare the expression of C‑X‑C motif chemokine receptor 4 (CXCR4) in co‑cultured AMSCs and to investigate the roles of the stromal cell‑derived factor‑1 (SDF‑1)/CXCR4 axis in the homing and migration of AMSCs. AMSCs were isolated from human amniotic membranes, purified and then differentiated into osteoblasts and adipocytes in vitro, which was verified by von Kossa Staining and Oil Red O staining. Cell viability was measured by Cell Counting kit‑8 and trypan blue assays at 24, 48 and 72 h, the expression of CXCR4 was analyzed by immunofluorescence‑based flow cytometry and reverse transcription‑quantitative polymerase chain reaction, and the migration ability of AMSCs in vitro was observed by a migration assay. The results demonstrated that cell viability (at 48 and 72 h) and survival (at 24, 48 and 72 h) in the co‑culture and serum groups were higher compared with the serum‑free group. Furthermore, CXCR4 mRNA and protein expression, and migration along the SDF‑1 gradient, in the co‑culture and serum‑free groups were higher compared with the serum group. Overall, the results indicated that AMSCs co‑cultured with AECs exhibited enhanced proliferation activity and survival rate. In conclusion, the present study demonstrated that co‑culture of AMSCs with AECs upregulated CXCR4 on the surface of AMSCs and enhanced the migration ability of AMSCs in vitro. This result may improve the directional migration and homing ability of AMSCs, as well as provide a theoretical basis for the application of AMSCs in clinical practice as a novel strategy to increase the success of hematopoietic stem cell transplantation.

Paracrine effects of human amniotic epithelial cells protect against chemotherapy-induced ovarian damage

Background

Human amniotic epithelial cells (hAECs) are attractive candidates for regenerative medical therapy, with the potential to replace deficient cells and improve functional recovery after injury. Previous studies have demonstrated that transplantation of hAECs effectively alleviate chemotherapy-induced ovarian damage via inhibiting granulose cells apoptosis in animal models of premature ovarian failure/insufficiency (POF/POI). However, the underlying molecular mechanism accounting for hAECs-mediated ovarian function recovery is not fully understood.

Methods

To investigate whether hAECs-secreting cytokines act as molecular basis to attenuate chemotherapy-induced ovarian injury, hAECs or hAEC-conditioned medium (hAEC-CM) was injected into the unilateral ovary of POF/POI mouse. Follicle development was evaluated by H&E staining at 1, 2 months after hAECs or hAEC-CM treatment. In addition, we performed a cytokine array containing 507 human cytokines on hAECs-derived serum-free conditioned medium. Finally, we further investigated whether hAECs could affect chemotherapy-induced apoptosis in primary human granulosa-lutein (hGL) cells and the tube formation of human umbilical vein endothelial cells (hUVECs) via a co-culture system in vitro.

Results

We observed the existence of healthy and mature follicles in ovaries treated with hAECs or hAEC-CM, whereas seriously fibrosis and many atretic follicles were found in the contralateral untreated ovaries of the same mouse. To distinguish cytokines involved in the process of hAECs-restored ovarian function, hAEC-CM was analyzed with a human cytokines array. Results revealed that 109 cytokines in hAEC-CM might participate in a variety of biological processes including apoptosis, angiogenesis, cell cycle and immune response. In vitro experiments, hAECs significantly inhibited chemotherapy-induced apoptosis and activated TGF-β/Smad signaling pathway within primary granulosa-lutein cells in paracrine manner. Furthermore, hAEC-CM was shown to promote angiogenesis in the injured ovaries and enhance the tube formation of human umbilical vein endothelial cells (hUVECs) in co-culture system.

Conclusions

These findings demonstrated that paracrine might be a key pathway in the process of hAECs-mediating ovarian function recovery in animal models of premature ovarian failure/insufficiency (POF/POI).

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0721-0) contains supplementary material, which is available to authorized users.

Effects of neuritin on the differentiation of bone marrow‑derived mesenchymal stem cells into neuron‑like cells

While the neurotrophic factor neuritin is known to be involved in neurodevelopment, the effects of this compound on cell differentiation remain unclear. The present study demonstrated that neuritin treatment induced the differentiation of rat bone marrow-derived mesenchymal stem cells (rBM-MSCs) into neuron-like (NL) cells. For these analyses, rBM-MSCs were incubated with 0.5 µg/ml neuritin for 24 h. Following induction, 27% of the rBM-MSCs exhibited typical NL cell morphologies. Subsequently, NL cells were characterized by examining the expression of neuronal markers and by analysis of cell functions. The findings demonstrated that the NL cells produced by neuritin treatment expressed the neuronal markers neuron-specific enolase and microtubule associate protein 2, and secreted the neurotransmitter 5-hydroxytryptamine. Furthermore, the NL cells exhibited certain partial neural-electrophysiological functions. In conclusion, neuritin treatment may be an effective method for inducing the differentiation of BM-MSCs towards NL cells. This may provide an alternative, potentially complementary tool for disease modeling and the development of cell-based therapies.

Umbilical cord: an unlimited source of cells differentiable towards dopaminergic neurons

Cell replacement therapy utilizing mesenchymal stem cells as its main resource holds great promise for ultimate treatment of human neurological disorders. Parkinson's disease (PD) is a common, chronic neurodegenerative disorder hallmarked by localized degeneration of a specific set of dopaminergic neurons within a midbrain sub-region. The specific cell type and confined location of degenerating neurons make cell replacement therapy ideal for PD treatment since it mainly requires replenishment of lost dopaminergic neurons with fresh and functional ones. Endogenous as well as exogenous cell sources have been identified as candidate targets for cell replacement therapy in PD. In this review, umbilical cord mesenchymal stem cells (UCMSCs) are discussed as they provide an inexpensive unlimited reservoir differentiable towards functional dopaminergic neurons that potentially lead to long-lasting behavioral recovery in PD patients. We also present miRNAs-mediated neuronal differentiation of UCMSCs. The UCMSCs bear a number of outstanding characteristics including their non-tumorigenic, low-immunogenic properties that make them ideal for cell replacement therapy purposes. Nevertheless, more investigations as well as controlled clinical trials are required to thoroughly confirm the efficacy of UCMSCs for therapeutic medical-grade applications in PD.

Tissue engineering for neurodegenerative diseases using human amniotic membrane and umbilical cord

Regenerative medicine, based on the use of stem cells, scaffolds and growth factors, has the potential to be a good approach for restoring damaged tissues of the central nervous system. This study investigated the use of human amniotic mesenchymal stem cells (hAMSC), human amniotic epithelial stem cells (hAESC), and human Wharton's jelly mesenchymal stem cells (hWJMSC) derived from human umbilical cord as a source of stem cells, and the potential of the human amniotic membrane (HAM) as a scaffold and/or source of growth factors to promote nerve regeneration. The hAMSC and hAESC obtained from HAM and the hWJMSC from umbilical cords were cultured in induction medium to obtain neural-like cells. The morphological differentiation of hAMSC, hAESC and hWJMSC into neural-like cells was evident after 4-5 days, when they acquired an elongated and multipolar shape, and at 21 days, when they expressed neural and glial markers. On other way, the HAM was completely decellularized without affecting the components of the basement membrane or the matrix. Subsequently, hAMSC, hAESC and hWJMSC differentiated into neural-like cells were seeded onto the decellularized HAM, maintaining their morphology. Finally, conditioned media from the HAM allowed proliferation of hAMSC, hAESC and hWJMSC differentiated to neural-like cells. Both HAM and umbilical cord are biomaterials with great potential for use in regenerative medicine for the treatment of neurodegenerative diseases.

Role of Nurr1 in the Generation and Differentiation of Dopaminergic Neurons from Stem Cells

NURR1 is an essential transcription factor for the differentiation, maturation, and maintenance of midbrain dopaminergic neurons (DA neurons) as it has been demonstrated using knock-out mice. DA neurons of the substantia nigra pars compacta degenerate in Parkinson's disease (PD) and mutations in the Nurr1 gene have been associated with this human disease. Thus, the study of NURR1 actions in vivo is fundamental to understand the mechanisms of neuron generation and degeneration in the dopaminergic system. Here, we present and discuss findings indicating that NURR1 is a valuable molecular tool for the in vitro generation of DA neurons which could be used for modeling and studying PD in cell culture and in transplantation approaches. Transduction of Nurr1 alone or in combination with other transcription factors such as Foxa2, Ngn2, Ascl1, and Pitx3, induces the generation of DA neurons, which upon transplantation have the capacity to survive and restore motor behavior in animal models of PD. We show that the survival of transplanted neurons is increased when the Nurr1-transduced olfactory bulb stem cells are treated with GDNF. The use of these and other factors with the induced pluripotent stem cell (iPSC)-based technology or the direct reprogramming of astrocytes or fibroblasts into human DA neurons has produced encouraging results for the study of the cellular and molecular mechanisms of neurodegeneration in PD and for the search of new treatments for this disease.

Therapeutic Effects of Umbilical Cord Blood Derived Mesenchymal Stem Cell-Conditioned Medium on Pulmonary Arterial Hypertension in Rats

Background:

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) may have multiple therapeutic applications for cell based therapy including the treatment of pulmonary artery hypertension (PAH). As low survival rates and potential tumorigenicity of implanted cells could undermine the mesenchymal stem cell (MSC) cell-based therapy, we chose to investigate the use of conditioned medium (CM) from a culture of MSC cells as a feasible alternative.

Methods:

CM was prepared by culturing hUCB-MSCs in three-dimensional spheroids. In a rat model of PAH induced by monocrotaline, we infused CM or the control unconditioned culture media via the tail-vein of 6-week-old Sprague-Dawley rats.

Results:

Compared with the control unconditioned media, CM infusion reduced the ventricular pressure, the right ventricle/(left ventricle+interventricular septum) ratio, and maintained respiratory function in the treated animals. Also, the number of interleukin 1α (IL-1α), chemokine (C-C motif) ligand 5 (CCL5), and tissue inhibitor of metalloproteinase 1 (TIMP-1)–positive cells increased in lung samples and the number of terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling technique (TUNEL)–positive cells decreased significantly in the CM treated animals.

Conclusions:

From our in vivo data in the rat model, the observed decreases in the TUNEL staining suggest a potential therapeutic benefit of the CM in ameliorating PAH-mediated lung tissue damage. Increased IL-1α, CCL5, and TIMP-1 levels may play important roles in this regard.

An Overview on Human Umbilical Cord Blood Stem Cell-Based Alternative In Vitro Models for Developmental Neurotoxicity Assessment

The developing brain is found highly vulnerable towards the exposure of different environmental chemicals/drugs, even at concentrations, those are generally considered safe in mature brain. The brain development is a very complex phenomenon which involves several processes running in parallel such as cell proliferation, migration, differentiation, maturation and synaptogenesis. If any step of these cellular processes hampered due to exposure of any xenobiotic/drug, there is almost no chance of recovery which could finally result in a life-long disability. Therefore, the developmental neurotoxicity (DNT) assessment of newly discovered drugs/molecules is a very serious concern among the neurologists. Animal-based DNT models have their own limitations such as ethical concerns and lower sensitivity with less predictive values in humans. Furthermore, non-availability of human foetal brain tissues/cells makes job more difficult to understand about mechanisms involve in DNT in human beings. Although, the use of cell culture have been proven as a powerful tool for DNT assessment, but many in vitro models are currently utilizing genetically unstable cell lines. The interpretation of data generated using such terminally differentiated cells is hard to extrapolate with in vivo situations. However, human umbilical cord blood stem cells (hUCBSCs) have been proposed as an excellent tool for alternative DNT testing because neuronal development from undifferentiated state could exactly mimic the original pattern of neuronal development in foetus when hUCBSCs differentiated into neuronal cells. Additionally, less ethical concern, easy availability and high plasticity make them an attractive source for establishing in vitro model of DNT assessment. In this review, we are focusing towards recent advancements on hUCBSCs-based in vitro model to understand DNTs.

Human umbilical cord mesenchymal stem cell-loaded amniotic membrane for the repair of radial nerve injury

In this study, we loaded human umbilical cord mesenchymal stem cells onto human amniotic membrane with epithelial cells to prepare nerve conduits, i.e., a relatively closed nerve regeneration chamber. After neurolysis, the injured radial nerve was enwrapped with the prepared nerve conduit, which was fixed to the epineurium by sutures, with the cell on the inner surface of the conduit. Simultaneously, a 1.0 mL aliquot of human umbilical cord mesenchymal stem cell suspension was injected into the distal and proximal ends of the injured radial nerve with 1.0 cm intervals. A total of 1.75 × 10⁷ cells were seeded on the amniotic membrane. In the control group, patients received only neurolysis. At 12 weeks after cell transplantation, more than 80% of patients exhibited obvious improvements in muscular strength, and touch and pain sensations. In contrast, these improvements were observed only in 55–65% of control patients. At 8 and 12 weeks, muscular electrophysiological function in the region dominated by the injured radial nerve was significantly better in the transplantation group than the control group. After cell transplantation, no immunological rejections were observed. These findings suggest that human umbilical cord mesenchymal stem cell-loaded amniotic membrane can be used for the repair of radial nerve injury.

Ischemic preconditioning for cell-based therapy and tissue engineering

Cell- and tissue-based therapies are innovative strategies to repair and regenerate injured hearts. Despite major advances achieved in optimizing these strategies in terms of cell source and delivery method, the clinical outcome of cell-based therapy remains unsatisfactory. The non-genetic approach of ischemic/hypoxic preconditioning to enhance cell- and tissue-based therapies has received much attention in recent years due to its non-invasive drug-free application. Here we discuss the current development of hypoxic/ischemic preconditioning to enhance stem cell-based cardiac repair and regeneration.