Human umbilical cord blood mononuclear cells and chorionic plate-derived mesenchymal stem cells promote axon survival in a rat model of optic nerve crush injury

The Placenta as a Source of Human Material for Neuronal Repair

Stem cell therapy has the potential to meet unsolved problems in tissue repair and regeneration, particularly in the neural tissues. However, an optimal source has not yet been found. Growing evidence indicates that positive effects produced in vivo by mesenchymal stem cells (MSCs) can be due not only to their plasticity but also to secreted molecules including extracellular vesicles (EVs) and the extracellular matrix (ECM). Trophic effects produced by MSCs may reveal the key to developing effective tissue-repair strategies, including approaches based on brain implants or other implantable neural electrodes. In this sense, MSCs will become increasingly valuable and needed in the future. The placenta is a temporary organ devoted to protecting and supporting the fetus. At the same time, the placenta represents an abundant and extremely convenient source of MSCs. Nonetheless, placenta-derived MSCs (P-MSCs) remain understudied as compared to MSCs isolated from other sources. This review outlines the limited literature describing the neuroregenerative effects of P-MSC-derived biomaterials and advocates for exploiting the potential of this untapped source for human regenerative therapies.

Mesenchymal stem cells for repairing glaucomatous optic nerve

Glaucoma is a common and complex neurodegenerative disease characterized by progressive loss of retinal ganglion cells (RGCs) and axons. Currently, there is no effective method to address the cause of RGCs degeneration. However, studies on neuroprotective strategies for optic neuropathy have increased in recent years. Cell replacement and neuroprotection are major strategies for treating glaucoma and optic neuropathy. Regenerative medicine research into the repair of optic nerve damage using stem cells has received considerable attention. Stem cells possess the potential for multidirectional differentiation abilities and are capable of producing RGC-friendly microenvironments through paracrine effects. This article reviews a thorough researches of recent advances and approaches in stem cell repair of optic nerve injury, raising the controversies and unresolved issues surrounding the future of stem cells.

Molecular and Cellular Insights: A Focus on Glycans and the HNK1 Epitope in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a synaptic disorder with a GABA/glutamate imbalance in the perineuronal nets and structural abnormalities such as increased dendritic spines and decreased long distance connections. Specific pregnancy disorders significantly increase the risk for an ASD phenotype such as preeclampsia, preterm birth, hypoxia phenomena, and spontaneous miscarriages. They are associated with defects in the glycosylation-immune placental processes implicated in neurogenesis. Some glycans epitopes expressed in the placenta, and specifically in the extra-villous trophoblast also have predominant functions in dendritic process and synapse function. Among these, the most important are CD57 or HNK1, CD22, CD24, CD33 and CD45. They modulate the innate immune cells at the maternal-fetal interface and they promote foeto-maternal tolerance. There are many glycan-based pathways of immunosuppression. N-glycosylation pathway dysregulation has been found to be associated with autoimmune-like phenotypes and maternal-autoantibody-related (MAR) autism have been found to be associated with central, systemic and peripheric autoimmune processes. Essential molecular pathways associated with the glycan-epitopes expression have been found to be specifically dysregulated in ASD, notably the Slit/Robo, Wnt, and mTOR/RAGE signaling pathways. These modifications have important effects on major transcriptional pathways with important genetic expression consequences. These modifications lead to defects in neuronal progenitors and in the nervous system's implementation specifically, with further molecular defects in the GABA/glutamate system. Glycosylation placental processes are crucial effectors for proper maternofetal immunity and endocrine/paracrine pathways formation. Glycans/ galectins expression regulate immunity and neurulation processes with a direct link with gene expression. These need to be clearly elucidated in ASD pathophysiology.

Unveiling Neuroprotection and Regeneration Mechanisms in Optic Nerve Injury: Insight from Neural Progenitor Cell Therapy with Focus on Vps35 and Syntaxin12

Axonal degeneration resulting from optic nerve damage can lead to the progressive death of retinal ganglion cells (RGCs), culminating in irreversible vision loss. We contrasted two methods for inducing optic nerve damage: optic nerve compression (ONCo) and optic nerve crush (ONCr). These were assessed for their respective merits in simulating traumatic optic neuropathies and neurodegeneration. We also administered neural progenitor cells (NPCs) into the subtenon space to validate their potential in mitigating optic nerve damage. Our findings indicate that both ONCo and ONCr successfully induced optic nerve damage, as shown by increases in ischemia and expression of genes linked to neuronal regeneration. Post NPC injection, recovery in the expression of neuronal regeneration-related genes was more pronounced in the ONCo model than in the ONCr model, while inflammation-related gene expression saw a better recovery in ONCr. In addition, the proteomic analysis of R28 cells in hypoxic conditions identified Vps35 and Syntaxin12 genes. Vps35 preserved the mitochondrial function in ONCo, while Syntaxin12 appeared to restrain inflammation via the Wnt/β-catenin signaling pathway in ONCr. NPCs managed to restore damaged RGCs by elevating neuroprotection factors and controlling inflammation through mitochondrial homeostasis and Wnt/β-catenin signaling in hypoxia-injured R28 cells and in both animal models. Our results suggest that ischemic injury and crush injury cause optic nerve damage via different mechanisms, which can be effectively simulated using ONCo and ONCr, respectively. Moreover, cell-based therapies such as NPCs may offer promising avenues for treating various optic neuropathies, including ischemic and crush injuries.

Mesenchymal stem cells alleviate aging in vitro and in vivo

BACKGROUND

Aging is a natural and multi-factorial phenomenon associated with multiple human pathologies. Mesenchymal stem cells (MSCs) hold great promise in clinical fields of medicine including tissue repair, cardiovascular disease, and brain ischemic injury. The purpose of this study was to explore the roles of MSCs in improving the condition of aging cells, repairing aging tissues and organs, and extending the life span of elderly mice.

METHODS

This study was carried out both in vitro and in vivo. We used MSCs to intervene with IMR-90 senescent cells induced by D-galactose and aged C57BL/6 mice.

RESULTS

After 48 hours of co-culturing the aged cells with MSCs, the up-regulated expression of inflammatory factor, interleukin 6 (IL6), and the down-regulated expression of several growth factors, such as transforming growth factor (TGFβ1) and growth differentiation factor (GDF11), in D-galactose induced senescent cells were reversed. Moreover, compared with aged cells, the number of mitochondria and the telomere length were increased with MSC treatment. Similarly, in aged mice, the symptoms related to aging were improved after MSC treatment: the mouse hair became shiny and dense, and the symptoms of bladder overactivity were relieved. Hematoxylin and eosin (H&E) and Masson's trichrome staining showed that the histopathological changes in skin, bladder, liver, and lung were apparently improved.

CONCLUSIONS

Treatment with MSCs effectively improves aging-related phenotypes and plays a beneficial role in improving aging and aging-related diseases.

GAP-43 Induces the Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells into Retinal Ganglial-Like Cells

Optic neuritis (ON) is a common neurological disease, and the transplant of retinal ganglion cells (RGCs) has been thought as a promising strategy for improving the injury of the optic nerve system. Bone mesenchymal stem cells (BMSCs) have the potential to differentiate into neural cells. Several studies have indicated that GAP-43 is related with the regeneration of nerve cells, while the effect of GAP-43 on inducing BMSC differentiation remains unclear. In this study, the BMSCs were separated from the rats and identified with flow cytometry assay. The GAP-43 expressed vectors were transfected into the BMSCs, and the biomarkers of RGCs such as PAX6, LHX2, and ATOH7 were used to observe by qRT-PCR. Moreover, the effect of GAP-43-induced BMSCs (G-BMSCs) on ON improvement was also verified with rat models, and the activity of MAPK pathway was measured with western blot. Here, it was found that GAP-43 could obviously promote the differentiation of BMSCs, and increased PAX6, LHX2, ATOH7, BRN3A, and BRN3B were observed in the process of cell differentiation. Moreover, it was also found that G-BMSCs significantly increased the abundances of NFL and NFM in G-BMSCs, and GAP-43 could also enhance the activity of MAPK pathways in BMSCs. Therefore, this study suggested that GAP-43 could induce the differentiation of bone marrow-derived mesenchymal stem cells into retinal ganglial cells.

Exosomes: a new way of protecting and regenerating optic nerve after injury

As an important part of the central nervous system (CNS), the optic nerve usually cannot regenerate directly after injury. Therefore, treating the injury and restoring the function of the optic nerve are a historical problem in the medical field. Due to the special anatomical position of the optic nerve, the microenvironment needed for protection and regeneration after injury is lacking. Therefore, preventing the continued loss of neurons, protecting the functional nerves, and promoting the effective protection of nerves are the main ways to solve the problem. Exosomes are nano-sized vesicles with a diameter of 30-150 nm, composed of lipid bilayers, proteins, and genetic material. They have key functions in cell-to-cell communication, immune regulation, inflammation, and regeneration. More and more shreds of evidence show that exosomes not only play an important role in systemic diseases such as cancer, cardiovascular diseases, and brain diseases; they also play a key role in ophthalmological diseases. This article reviews the role of exosomes in the protection and regeneration of the optic nerve after optic nerve injury in related experimental studies and clinical treatment methods. GRAPHICAL ABSTARCT: .

Traumatic optic neuropathy: a review of current studies

Traumatic optic neuropathy (TON) is a serious complication of craniofacial trauma that directly or indirectly damages the optic nerve and can cause severe vision loss. The incidence of TON has been gradually increasing in recent years. Research on the protection and regeneration of the optic nerve after the onset of TON is still at the level of laboratory studies and which is insufficient to support clinical treatment of TON. And, due to without clear guidelines, there is much ambiguity regarding its diagnosis and management. Clinical interventions for TON include observation only, treatment with corticosteroids alone, or optic canal (OC) decompression (with or without steroids). There is controversy in clinical practice concerning which treatment is the best. A review of available studies shows that the visual acuity of patients with TON can be significantly improved after OC decompression surgery (especially endoscopic transnasal/transseptal optic canal decompression (ETOCD)) with or without the use of corticosteroids. And new findings of laboratory studies such as mitochondrial therapy, lipid change studies, and other studies in favor of TON therapy have also been identified. In this review, we discuss the evolving perspective of surgical treatment and experimental study.

Human Pluripotent Stem Cell-Derived Neural Progenitor Cells Promote Retinal Ganglion Cell Survival and Axon Recovery in an Optic Nerve Compression Animal Model

Human pluripotent stem cell-derived neural progenitor cells (NPCs) have the potential to recover from nerve injury. We previously reported that human placenta-derived mesenchymal stem cells (PSCs) have neuroprotective effects. To evaluate the potential benefit of NPCs, we compared them to PSCs using R28 cells under hypoxic conditions and a rat model of optic nerve injury. NPCs and PSCs (2 × 106 cells) were injected into the subtenon space. After 1, 2, and 4 weeks, we examined changes in target proteins in the retina and optic nerve. NPCs significantly induced vascular endothelial growth factor (Vegf) compared to age-matched shams and PSC groups at 2 weeks; they also induced neurofilaments in the retina compared to the sham group at 4 weeks. In addition, the expression of brain-derived neurotrophic factor (Bdnf) was high in the retina in the NPC group at 2 weeks, while expression in the optic nerve was high in both the NPC and PSC groups. The low expression of ionized calcium-binding adapter molecule 1 (Iba1) in the retina had recovered at 2 weeks after NPC injection and at 4 weeks after PSC injection. The expression of the inflammatory protein NLR family, pyrin domain containing 3 (Nlrp3) was significantly reduced at 1 week, and that of tumor necrosis factor-α (Tnf-α) in the optic nerves of the NPC group was lower at 2 weeks. Regarding retinal ganglion cells, the expressions of Brn3a and Tuj1 in the retina were enhanced in the NPC group compared to sham controls at 4 weeks. NPC injections increased Gap43 expression from 2 weeks and reduced Iba1 expression in the optic nerves during the recovery period. In addition, R28 cells exposed to hypoxic conditions showed increased cell survival when cocultured with NPCs compared to PSCs. Both Wnt/β-catenin signaling and increased Nf-ĸb could contribute to the rescue of damaged retinal ganglion cells via upregulation of neuroprotective factors, microglial engagement, and anti-inflammatory regulation by NPCs. This study suggests that NPCs could be useful for the cellular treatment of various optic neuropathies, together with cell therapy using mesenchymal stem cells.

Neurotrophin-3 upregulation associated with intravenous transplantation of bone marrow mononuclear cells induces axonal sprouting and motor functional recovery in the long term after neocortical ischaemia

Bone marrow mononuclear cells (BMMCs) have been identified as a relevant therapeutic strategy for the treatment of several chronic diseases of the central nervous system. The aim of this work was to evaluate whether intravenous treatment with BMMCs facilitates the reconnection of lesioned cortico-cortical and cortico-striatal pathways, together with motor recovery, in injured adult Wistar rats using an experimental model of unilateral focal neocortical ischaemia. Animals with cerebral cortex ischaemia underwent neural tract tracing for axonal fibre analysis, differential expression analysis of genes involved in apoptosis and neuroplasticity by RT-qPCR, and motor performance assessment by the cylinder test. Quantitative and qualitative analyses of axonal fibres labelled by an anterograde neural tract tracer were performed. Ischaemic animals treated with BMMCs showed a significant increase in axonal sprouting in the ipsilateral neocortex and in the striatum contralateral to the injured cortical areas compared to untreated rodents. In BMMC-treated animals, there was a trend towards upregulation of the Neurotrophin-3 gene compared to the other genes, as well as modulation of apoptosis by BMMCs. On the 56th day after ischaemia, BMMC-treated animals showed significant improvement in motor performance compared to untreated rats. These results suggest that in the acute phase of ischaemia, Neurotrophin-3 is upregulated in response to the lesion itself. In the long run, therapy with BMMCs causes axonal sprouting, reconnection of damaged neuronal circuitry and a significant increase in motor performance.

Current Status and Future Prospects of Perinatal Stem Cells

The placenta is a temporary organ that is discarded after birth and is one of the most promising sources of various cells and tissues for use in regenerative medicine and tissue engineering, both in experimental and clinical settings. The placenta has unique, intrinsic features because it plays many roles during gestation: it is formed by cells from two individuals (mother and fetus), contributes to the development and growth of an allogeneic fetus, and has two independent and interacting circulatory systems. Different stem and progenitor cell types can be isolated from the different perinatal tissues making them particularly interesting candidates for use in cell therapy and regenerative medicine. The primary source of perinatal stem cells is cord blood. Cord blood has been a well-known source of hematopoietic stem/progenitor cells since 1974. Biobanked cord blood has been used to treat different hematological and immunological disorders for over 30 years. Other perinatal tissues that are routinely discarded as medical waste contain non-hematopoietic cells with potential therapeutic value. Indeed, in advanced perinatal cell therapy trials, mesenchymal stromal cells are the most commonly used. Here, we review one by one the different perinatal tissues and the different perinatal stem cells isolated with their phenotypical characteristics and the preclinical uses of these cells in numerous pathologies. An overview of clinical applications of perinatal derived cells is also described with special emphasis on the clinical trials being carried out to treat COVID19 pneumonia. Furthermore, we describe the use of new technologies in the field of perinatal stem cells and the future directions and challenges of this fascinating and rapidly progressing field of perinatal cells and regenerative medicine.

Treatment of traumatic optic neuropathy using human placenta-derived mesenchymal stem cells in Asian patients

Aim: To assess the safety and feasibility of subtenon transplantation of human placenta-derived mesenchymal stem cells (hPMSCs) in Asian patients with traumatic optic neuropathy. Materials & methods: The survival of retinal ganglion cells in the rat retina was evaluated by monitoring the expression of Tuj1 and Gfap after optic nerve compression. Based on the preclinical data, we conducted a Phase I, open label, single center, nonrandomized clinical trial in four Asian traumatic optic neuropathy patients. The safety and ophthalmologic changes were evaluated. Results: The levels of Tuj1 and Gfap expression were significantly increased in the hPMSC treatment group compared with the sham group, suggesting a protective effect of hPMSCs on the optic nerve and retinal ganglion cells. There was no evidence of adverse proliferation, tumorigenicity, severe inflammation or other serious issues during the 12-month follow-up period. Visual acuity improved in all four patients. Conclusion: The results suggested that hPMSCs are safe and have potential utility in regenerative medicine. Clinical trial registration number: 20150196587 (Korean FDA), 2015-07-123-054 (IRB).

Antioxidant and Biological Properties of Mesenchymal Cells Used for Therapy in Retinitis Pigmentosa

Both tissue repair and regeneration are a priority in regenerative medicine. Retinitis pigmentosa (RP), a complex retinal disease characterized by the progressive loss of impaired photoreceptors, is currently lacking effective therapies: this represents one of the greatest challenges in the field of ophthalmological research. Although this inherited retinal dystrophy is still an incurable genetic disease, the oxidative damage is an important pathogenetic element that may represent a viable target of therapy. In this review, we summarize the current neuroscientific evidence regarding the effectiveness of cell therapies in RP, especially those based on mesenchymal cells, and we focus on their therapeutic action: limitation of both oxidative stress and apoptotic processes triggered by the disease and promotion of cell survival. Cell therapy could therefore represent a feasible therapeutic option in RP.

Mesenchymal stem cell surgery, rescue and regeneration in retinitis pigmentosa: clinical and rehabilitative prognostic aspects

Purpose:

To assess whether treatment with the Limoli Retinal Restoration Technique (LRRT) can be performed in patients with retinitis pigmentosa (RP), grafting the autologous cells in a deep scleral pocket above the choroid of each eye to exert their beneficial effect on the residual retinal cells.

Methods:

The patients were subjected to a complete ophthalmological examination, including best corrected visual acuity (BCVA), close-up visus measurements, spectral domain-optical coherence tomography (SD-OCT), microperimetry (MY), and electroretinography (ERG). Furthermore, the complete ophthalmological examination was carried out at baseline (T0) and at 6 months (T180) after surgery. The Shapiro–Wilk test was used to assess the normality of distribution of the investigated parameters. A mixed linear regression model was used to analyse the difference in all the studied parameters at T0 and T180, and to compare the mean change between the two groups. All statistical analyses were performed with STATA 14.0 (Collage Station, Texas, USA).

Results:

LRRT treatment was performed in 34 eyes of 25 RP patients recruited for the study. The eyes were classified in two groups on the basis of foveal thickness (FT) assessed by SD-OCT: 14 eyes in Group A (FT≤190μm) and the remaining 20 ones in Group B (FT > 190μm). Although it had not reached the statistical significance, Group B showed a better improvement in BCVA, residual close-up visus and sensitivity than Group A.

Conclusions:

Previous studies have described the role of LRRT in slowing down retinal degenerative diseases. Consequently, this surgical procedure could improve the clinical and rehabilitative prognostic parameters in RP patients. On the other hand, further clinical research and studies with longer follow-up will be needed to evaluate its efficacy.

Placenta-Derived Mesenchymal Stem Cells Restore the Ovary Function in an Ovariectomized Rat Model via an Antioxidant Effect

Oxidative stress is one of the major etiologies of ovarian dysfunction, including premature ovarian failure (POF). Previous reports have demonstrated the therapeutic effects of human placenta-derived mesenchymal stem cells (PD-MSCs) in an ovariectomized rat model (OVX). However, their therapeutic mechanism in oxidative stress has not been reported. Therefore, we investigated to profile the exosome of serum and demonstrate the therapeutic effect of PD-MSCs transplantation for the ovary function. We established an OVX model by ovariectomy and PD-MSCs transplantation was conducted by intravenous injection. Additionally, various factors in the exosome were profiled by LC-MS analysis. As a result, the transplanted PD-MSCs were engrafted into the ovary and the existence of antioxidant factors in the exosome. A decreased expression of oxidative stress markers and increased expression of antioxidant markers were shown in the transplantation (Tx) in comparison to the non-transplantation group (NTx) (* p < 0.05). The apoptosis factors were decreased, and ovary function was improved in Tx in comparison to NTx (* p < 0.05). These results suggest that transplanted PD-MSCs restore the ovarian function in an OVX model via upregulated antioxidant factors. These findings offer new insights for further understanding of stem cell therapy for reproductive systems.

Hypoxia-Preconditioned Placenta-Derived Mesenchymal Stem Cells Rescue Optic Nerve Axons Via Differential Roles of Vascular Endothelial Growth Factor in an Optic Nerve Compression Animal Model

Human placenta-derived stem cells (hPSCs) with the therapeutic potential to recover from optic nerve injury have been reported. We have recently demonstrated that hPSCs have protective abilities against hypoxic damage. To improve the capacity of hPSCs, we established a hypoxia-preconditioned strain (HPPCs) using a hypoxic chamber. The hPSCs were exposed to short-term hypoxic conditions of 2.2% O₂ and 5.5% CO₂. We also performed in vivo experiments to demonstrate the recovery effects of HPPCs using an optic nerve injury rat model. Naïve hPSCs (and HPPCs) were injected into the optic nerve. After 1, 2, or 4 weeks, we analyzed changes in target proteins in the optic nerve tissues. In the retina, GAP43 expression was higher in both groups of naïve hPSCs and HPPCs versus sham controls. Two weeks after injection, all hPSC-injected groups showed recovery of tuj1 expression in damaged retinas. We also determined GFAP expression in retinas using the same model. In optic nerve tissues, HIF-1α levels were significantly lower in the HPPC-injected group 1 week after injury, and Thy-1 levels were higher in the hPSC-injected group at 4 weeks. There was also an enhanced recovery of Thy-1 expression after HPPC injection. In addition, R28 cells exposed to hypoxic conditions showed improved viability through enhanced recovery of HPPCs than naïve hPSCs. VEGF protein was a mediator in the recovery pathway via upregulation of target proteins regulated by HPPCs. Our results suggest that HPPCs may be candidates for cell therapy for the treatment of traumatic optic nerve injury.

Umbilical Cord Blood and Serum for the Treatment of Ocular Diseases: A Comprehensive Review

Several blood derivatives have been proposed for the treatment of various ocular diseases that affect either the anterior or the posterior segment of the eye. Blood sources may range from the patient’s own peripheral blood (autologous) to donor tissues, mainly allogeneic peripheral blood and umbilical cord blood (UCB). The utilization of the latter permits the collection of a large amount of serum all at once, and is characterized by therapeutic feasibility in patients with a poor general condition or anemia and blood dyscrasia. Products derived from UCB have two potential uses. First, serum in the form of eye drops can be applied topically onto the ocular surface to efficiently treat anterior segment disorders such as dry eye syndrome or corneal epithelial defects with different etiologies. The rationale for and efficacy of this application derive from the high concentrations of biologically active components and growth factors in UCB, which can nourish the ocular surface. Second, UCB is a source of stem cells, which are used in the field of regenerative medicine because they differentiate into various mature cells, including corneal and retinal cells. Therefore, UCB-derived stem cells have been proposed as a replacement therapy for the treatment of retinal and optic nerve diseases, given that current standard treatments often fail. The present review explores the clinical results that have been obtained using UCB-derived products in the field of ophthalmology, as well as the current limitations of those products in this field. Furthermore, given the promising development of UCB-based therapies, possible future directions in this area are discussed.

Models and treatments for traumatic optic neuropathy and demyelinating optic neuritis

Pathologies of the optic nerve could result as primary insults in the visual tract or as secondary deficits due to inflammation, demyelination, or compressing effects of the surrounding tissue. The extent of damage may vary from mild to severe, differently affecting patient vision, with the most severe forms leading to complete uni- or bilateral visual loss. The aim of researchers and clinicians in the field is to alleviate the symptoms of these, yet uncurable pathologies, taking advantage of known and novel potential therapeutic approaches, alone or in combinations, and applying them in a limited time window after the insult. In this review, we discuss the epidemiological and clinical profile as well as the pathophysiological mechanisms of two main categories of optic nerve pathologies, namely traumatic optic neuropathy and optic neuritis, focusing on the demyelinating form of the latter. Moreover, we report on the main rodent models mimicking these pathologies or some of their clinical aspects. The current treatment options will also be reviewed and novel approaches will be discussed.

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

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

Placenta-Derived Adherent Stromal Cell Therapy for Hematopoietic Disorders: A Case Study of PLX-R18

The ephemeral placenta provides a noncontroversial source of young, healthy cells of both maternal and fetal origin from which cell therapy products can be manufactured. The 2 advantages of using live cells as therapeutic entities are: (a) in their environmental-responsive, multifactorial secretion profile and (b) in their activity as a “slow-release drug delivery system,” releasing secretions over a long time frame. A major difficulty in translating cell therapy to the clinic involves challenges of large-scale, robust manufacturing while maintaining product characteristics, identity, and efficacy. To address these concerns early on, Pluristem developed the PLacental eXpanded (PLX) platform, the first good manufacturing practice–approved, 3-dimensional bioreactor-based cell growth platform, to enable culture of mesenchymal-like adherent stromal cells harvested from the postpartum placenta. One of the products produced by Pluristem on this platform is PLX-R18, a product mainly comprising placental fetal cells, which is proven in vivo to alleviate radiation-induced lethality and to enhance hematopoietic cell counts after bone marrow (BM) failure. The identified mechanism of action of PLX-R18 cells is one of the cell-derived systemic pro-hematopoietic secretions, which upregulate endogenous secretions and subsequently rescue BM and peripheral blood cellularity, thereby boosting survival. PLX-R18 is therefore currently under study to treat both the hematopoietic syndrome of acute radiation (under the US Food and Drug Administration [FDA]’s Animal Rule) and the incomplete engraftment after BM transplantation (in a phase I study). In the future, they could potentially address additional hematological indications, such as aplastic anemia, myelodysplastic syndrome, primary graft failure, and acute or chronic graft versus host disease.

UMSC-derived exosomes promote retinal ganglion cells survival in a rat model of optic nerve crush

Traumatic optic neuropathy or glaucoma lead to retinal ganglion cells loss and cause blindness, and there is no effective therapy strategy by far. Mesenchymal cells from the Wharton's jelly of the umbilical cord (umbilical cord mesenchymal stem cells, UMSCs) and UMSC-derived exosomes (UMSC-Exos) are promising candidates for allogeneic therapy in regenerative medicine, but their effort on optic nerve injury and the underlying mechanism remains undefined. In the present study, we investigated the functions of UMSC-Exos in a rat optic nerve crush (ONC) model. After three times of treatments with an interval of one week, we found that the UMSC-Exos significantly promoted Brn3a⁺ retinal ganglion cells (RGCs) survival in retinal ganglion cell layer compared with PBS controls. UMSC-Exos also significantly promoted GFAP⁺ glia cells activation in retina and optic nerve. However, no increase of GAP43⁺ axon counts in the optic nerve was found after UMSC-Exos treatment. Thus, our results demonstrate that UMSC-derived exosomes may play a role in neuroprotection by promoting the RGCs survival and glia cells activation but not the axon regeneration.

Human Periodontal Ligament-Derived Stem Cells Promote Retinal Ganglion Cell Survival and Axon Regeneration After Optic Nerve Injury

Optic neuropathies are the leading cause of irreversible blindness and visual impairment in the developed countries, affecting more than 80 million people worldwide. While most optic neuropathies have no effective treatment, there is intensive research on retinal ganglion cell (RGC) protection and axon regeneration. We previously demonstrated potential of human periodontal ligament-derived stem cells (PDLSCs) for retinal cell replacement. Here, we report the neuroprotective effect of human PDLSCs to ameliorate RGC degeneration and promote axonal regeneration after optic nerve crush (ONC) injury. Human PDLSCs were intravitreally injected into the vitreous chamber of adult Fischer rats after ONC in vivo as well as cocultured with retinal explants in vitro. Human PDLSCs survived in the vitreous chamber and were maintained on the RGC layer even at 3 weeks after ONC. Immunofluorescence analysis of βIII-tubulin and Gap43 showed that the numbers of surviving RGCs and regenerating axons were significantly increased in the rats with human PDLSC transplantation. In vitro coculture experiments confirmed that PDLSCs enhanced RGC survival and neurite regeneration in retinal explants without inducing inflammatory responses. Direct cell-cell interaction and elevated brain-derived neurotrophic factor secretion, but not promoting endogenous progenitor cell regeneration, were the RGC protective mechanisms of human PDLSCs. In summary, our results revealed the neuroprotective role of human PDLSCs by strongly promoting RGC survival and axonal regeneration both in vivo and in vitro, indicating a therapeutic potential for RGC protection against optic neuropathies. Stem Cells 2018;36:844-855.

Future perspectives of cell therapy for neonatal hypoxic-ischemic encephalopathy

Neonatal ischemic brain injury causes permanent motor-deficit cerebral palsy. Hypoxic-ischemic encephalopathy (HIE) is a very serious condition that can result in death and disability. In 1997, we reported that irreversible neuronal cell damage is induced by the elevation of intracellular Ca ion concentration that has occurred in sequence after excess accumulation of the excitatory neurotransmitter glutamate during ischemia. We also reported that hypothermia was effective in treating ischemic brain damage in rats by suppressing energy loss and raising intracellular Ca ion concentration. Following the 2010 revised International Liaison Committee on Resuscitation guideline, our group developed the Guideline for the treatment of Hypothermia in Japan, and we started online case registry in January 2012. However, therapeutic hypothermia must be initiated within the first 6 h after birth. By contrast, cell therapy may have a much longer therapeutic time window because it might reduce apoptosis/oxidative stress and enhance the regenerative process. In 2014, we administered autologous umbilical cord blood stem cell (UCBC) therapy for neonatal HIE, for the first time in Japan. We enrolled five full-term newborns with moderate-to-severe HIE. Our autologous UCBC therapy is leading to new protocols for the prevention of ischemic brain damage.

Human placenta mesenchymal stem cells promote axon survival following optic nerve compression through activation of NF-κB pathway

Different damage factors are known to trigger cell death in the optic nerves. Use of mesenchymal stem cells is a possible treatments option for traumatic optic nerve injury due to their ability to secrete protective cytokines and recovery factors. In this study, we investigated the neuroprotective effects of human placenta-derived mesenchymal stem cells (hPMSCs) using an established optic nerve compression model and model of R28 cells that were exposed to hypoxia. Forty percent of axon death was seen in induced in vivo optic nerve injury model (p < .05), and 70% of R28 cells exposed to cobalt chloride (CoCl₂ ), leading to hypoxia, underwent apoptosis (p < .05). After intravenous injection of hPMSCs into tail vein, there was 25% improvement of axon survival in vivo (p < .05). R28 cells incubated with hPMSCs after exposure to hypoxic condition resulted in 50% increased cell survival compared with R28 cells without hPMSC exposure (p < .05), suggesting the active release of multiple factors related to cell survival. In addition, we found that Nf-κb protein mediates neuroprotection pathway via up-regulation of target proteins regulated by hPMSCs. Therefore, we assert that Nf-κb was one of the mediator proteins in a recovery pathway induced by hPMSCs. In conclusion, these indicate that transactivation of Nf-κb protein has a critical role in recovery mechanism by hPMSCs. We suggest that hPMSCs have abilities to recover neuronal damages by up-regulating the expression of genes associated with axon survival and can a better understanding of the possible role of hPMSCs in the treatment modalities of optic nerve injury.

Cellular Reparative Mechanisms of Mesenchymal Stem Cells for Retinal Diseases

The use of multipotent mesenchymal stem cells (MSCs) has been reported as promising for the treatment of numerous degenerative disorders including the eye. In retinal degenerative diseases, MSCs exhibit the potential to regenerate into retinal neurons and retinal pigmented epithelial cells in both in vitro and in vivo studies. Delivery of MSCs was found to improve retinal morphology and function and delay retinal degeneration. In this review, we revisit the therapeutic role of MSCs in the diseased eye. Furthermore, we reveal the possible cellular mechanisms and identify the associated signaling pathways of MSCs in reversing the pathological conditions of various ocular disorders such as age-related macular degeneration (AMD), retinitis pigmentosa, diabetic retinopathy, and glaucoma. Current stem cell treatment can be dispensed as an independent cell treatment format or with the combination of other approaches. Hence, the improvement of the treatment strategy is largely subjected by our understanding of MSCs mechanism of action.

Therapeutic efficacy of human umbilical cord mesenchymal stem cells transplantation against renal ischemia/reperfusion injury in rats

BACKGROUND

Acute kidney injury (AKI) is a common clinical problem raising the urgent needs to develop new strategies for treatment. The present study investigated the therapeutic potential of human umbilical cord - mesenchymal stem cells (HUC-MSCs) transplantation against renal ischemia/reperfusion injury (IRI) in rats.

METHODS

Twenty four male Wistar rats were assigned into two main groups, sham group (control group) and I/R group. I/R group was injected in the tail vein with either phosphate buffer saline (PBS) or HUC-MSCs.

RESULTS

The HUC-MSCs improved kidney injury induced by I/R as demonstrated by enhancement of the kidney function via decreasing serum levels of creatinine, urea and uric acid. The therapeutic efficacy of HUC-MSCs were found to be mediated through anti-oxidant activity as indicated by significant reduction in total malondialdehyde (MDA) and significant increment in the levels of reduced glutathione (GSH), catalase (CAT) and glutathione-S-transferase (GST).

CONCLUSION

The present work suggests that HUC-MSCs may be an effective therapeutic agent against renal IRI. The recorded data showed improvement of renal functions and urine albumin in HUC-MSCs than IRI group with positive antioxidant efficacy of HUC-MSCs through scavenging free radicals and supporting the antioxidant enzymes.

Neural stem cells over-expressing brain-derived neurotrophic factor promote neuronal survival and cytoskeletal protein expression in traumatic brain injury sites

Cytoskeletal proteins are involved in neuronal survival. Brain-derived neurotrophic factor can increase expression of cytoskeletal proteins during regeneration after axonal injury. However, the effect of neural stem cells genetically modified by brain-derived neurotrophic factor transplantation on neuronal survival in the injury site still remains unclear. To examine this, we established a rat model of traumatic brain injury by controlled cortical impact. At 72 hours after injury, 2 × 10⁷ cells/mL neural stem cells overexpressing brain-derived neurotrophic factor or naive neural stem cells (3 mL) were injected into the injured cortex. At 1–3 weeks after transplantation, expression of neurofilament 200, microtubule-associated protein 2, actin, calmodulin, and beta-catenin were remarkably increased in the injury sites. These findings confirm that brain-derived neurotrophic factor-transfected neural stem cells contribute to neuronal survival, growth, and differentiation in the injury sites. The underlying mechanisms may be associated with increased expression of cytoskeletal proteins and the Wnt/β-catenin signaling pathway.