Human bone marrow mesenchymal stem cells protect catecholaminergic and serotonergic neuronal perikarya and transporter function from oxidative stress by the secretion of glial-derived neurotrophic factor

Mesenchymal stromal cell-derived secretome-based therapy for neurodegenerative diseases: overview of clinical trials

BACKGROUND

Over the past few years, mesenchymal stromal cells (MSCs) have attracted a great deal of scientific attention owing to their promising results in the treatment of incurable diseases. However, there are several concerns about their possible side effects after direct cell transplantation, including host immune response, time-consuming cell culture procedures, and the dependence of cell quality on the donor, which limit the application of MSCs in clinical trials. On the other hand, it is well accepted that the beneficial effects of MSCs are mediated by secretome rather than cell replacement. MSC secretome refers to a variety of bioactive molecules involved in different biological processes, specifically neuro-regeneration.

MAIN BODY

Due to the limited ability of the central nervous system to compensate for neuronal loss and relieve disease progress, mesenchymal stem cell products may be used as a potential cure for central nervous system disorders. In the present study, the therapeutic effects of MSC secretome were reviewed and discussed the possible mechanisms in the three most prevalent central nervous system disorders, namely Alzheimer's disease, multiple sclerosis, and Parkinson's disease. The current work aimed to help discover new medicine for the mentioned complications.

CONCLUSION

The use of MSC-derived secretomes in the treatment of the mentioned diseases has encouraging results, so it can be considered as a treatment option for which no treatment has been introduced so far.

Stem Cell-based and Advanced Therapeutic Modalities for Parkinson's Disease: A Risk-effectiveness Patient-centered Analysis

Treatment of Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, is currently considered a challenging issue since it causes substantial disability, poor quality of life, and mortality. Despite remarkable progress in advanced conventional therapeutic interventions, the global burden of the disease has nearly doubled, prompting us to assess the riskeffectiveness of different treatment modalities. Each protocol could be considered as the best alternative treatment depending on the patient's situation. Prescription of levodopa, the most effective available medicine for this disorder, has been associated with many complications, i.e., multiple episodes of "off-time" and treatment resistance. Other medications, which are typically used in combination with levodopa, may have several adverse effects as well. As a result, the therapies that are more in line with human physiology and make the least interference with other pathways are worth investigating. On the other hand, remaining and persistent symptoms after therapy and the lack of effective response to the conventional approaches have raised expectations towards innovative alternative approaches, such as stem cell-based therapy. It is critical to not overlook the unexplored side effects of innovative approaches due to the limited number of research. In this review, we aimed to compare the efficacy and risk of advanced therapies with innovative cell-based and stemcell- based modalities in PD patients. This paper recapitulated the underlying factors/conditions, which could lead us to more practical and established therapeutic outcomes with more advantages and few complications. It could be an initial step to reconsider the therapeutic blueprint for patients with Parkinson's disease.

Transcription factor EB-mediated mesenchymal stem cell therapy induces autophagy and alleviates spinocerebellar ataxia type 3 defects in neuronal cells model

Defects in ataxin-3 proteins and CAG repeat expansions in its coding gene ATXN3 cause Spinocerebellar Ataxia Type 3 (SCA3) or Machado-Joseph disease (MJD) polyglutamine neurodegenerative disease. The mutant proteins aggregate as inclusion bodies in cells and compete with wild-type ataxin-3, which leads to neuronal dysfunction or death and impairs Beclin1-mediated autophagy. It has been reported that Mesenchymal stem cells (MSCs) can reliably treat several neurodegenerative diseases. Herein, we used a Transcription Factor EB (TFEB) nuclear translocation-mediated MSCs co-culture approach to reconstitute autophagy and lysosomal biogenesis, and reduce SCA3-like behaviors in induced pluripotent stem cells (iPSCs)-derived neuron cells models. Our iPSCs model showed enhanced expression of autophagy proteins, attenuated the expression and toxic effects of mutant ataxin-3 on neurons, and alleviated the effects of ataxin-3 on autophagy. Therefore, MSCs are associated with autophagy-inducing therapy and compared to animal models, our MSCs co-culture could be used as a novel and potential therapeutic approach to study SCA3 disease and other neurodegenerative diseases.

Pro-angiogenic approach for skeletal muscle regeneration

The angiogenesis process is a phenomenon in which numerous molecules participate in the stimulation of the new vessels' formation from pre-existing vessels. Angiogenesis is a crucial step in tissue regeneration and recovery of organ and tissue function. Muscle diseases affect millions of people worldwide overcome the ability of skeletal muscle to self-repair. Pro-angiogenic therapies are key in skeletal muscle regeneration where both myogenesis and angiogenesis occur. These therapies have been based on mesenchymal stem cells (MSCs), exosomes, microRNAs (miRs) and delivery of biological factors. The use of different calls of biomaterials is another approach, including ceramics, composites, and polymers. Natural polymers are use due its bioactivity and biocompatibility in addition to its use as scaffolds and in drug delivery systems. One of these polymers is the natural rubber latex (NRL) which is biocompatible, bioactive, versatile, low-costing, and capable of promoting tissue regeneration and angiogenesis. In this review, the advances in the field of pro-angiogenic therapies are discussed.

Reduced expression of mitochondrial fumarate hydratase in progressive multiple sclerosis contributes to impaired in vitro mesenchymal stromal cell-mediated neuroprotection

Background:

Cell-based therapies for multiple sclerosis (MS), including those employing autologous bone marrow-derived mesenchymal stromal cells (MSC) are being examined in clinical trials. However, recent studies have identified abnormalities in the MS bone marrow microenvironment.

Objective:

We aimed to compare the secretome of MSC isolated from control subjects (C-MSC) and people with MS (MS-MSC) and explore the functional relevance of findings.

Methods:

We employed high throughput proteomic analysis, enzyme-linked immunosorbent assays and immunoblotting, as well as in vitro assays of enzyme activity and neuroprotection.

Results:

We demonstrated that, in progressive MS, the MSC secretome has lower levels of mitochondrial fumarate hydratase (mFH). Exogenous mFH restores the in vitro neuroprotective potential of MS-MSC. Furthermore, MS-MSC expresses reduced levels of fumarate hydratase (FH) with downstream reduction in expression of master regulators of oxidative stress.

Conclusions:

Our findings are further evidence of dysregulation of the bone marrow microenvironment in progressive MS with respect to anti-oxidative capacity and immunoregulatory potential. Given the clinical utility of the fumaric acid ester dimethyl fumarate in relapsing–remitting MS, our findings have potential implication for understanding MS pathophysiology and personalised therapeutic intervention.

Anti-inflammatory Effects of Mesenchymal Stem Cells and Their Secretomes in Pneumonia

Mesenchymal stem cells (MSCs) are multipotent progenitor cells that play crucial roles in the microenvironment of injured tissues. The potential therapeutics of MSCs have attracted extensive attention for several diseases such as acute respiratory distress syndrome (ARDS) and novel coronavirus disease 2019 (COVID-19) pneumonia. MSC-extracellular vesicles have been isolated from MSC-conditioned media (MSC-CM) with similar functional effects as parent MSCs. The therapeutic role of MSCs can be achieved through the balance between the inflammatory and regenerative microenvironments. Clinical settings of MSCs and their extracellular vesicles remain promising for many diseases, such as ARDS and pneumonia. However, their clinical applications remain limited due to the cost of growing and storage facilities of MSCs with a lack of standardized MSC-CM. This review highlights the proposed role of MSCs in pulmonary diseases and discusses the recent advances of MSC application for pneumonia and other lung disorders.

Small extracellular vesicles released by infused mesenchymal stromal cells target M2 macrophages and promote TGF-β upregulation, microvascular stabilization and functional recovery in a rodent model of severe spinal cord injury

Intravenous (IV) infusion of bone marrow-derived mesenchymal stem/stromal cells (MSCs) stabilizes the blood-spinal cord barrier (BSCB) and improves functional recovery in experimental models of spinal cord injury (SCI). Although IV delivered MSCs do not traffic to the injury site, IV delivered small extracellular vesicles (sEVs) derived from MSCs (MSC-sEVs) do and are taken up by a subset of M2 macrophages. To test whether sEVs released by MSCs are responsible for the therapeutic effects of MSCs, we tracked sEVs produced by IV delivered DiR-labelled MSCs (DiR-MSCs) after transplantation into SCI rats. We found that sEVs were released by MSCs in vivo, trafficked to the injury site, associated specifically with M2 macrophages and co-localized with exosome markers. Furthermore, while a single MSC injection was sufficient to improve locomotor recovery, fractionated dosing of MSC-sEVs over 3 days (F-sEVs) was required to achieve similar therapeutic effects. Infusion of F-sEVs mimicked the effects of single dose MSC infusion on multiple parameters including: increased expression of M2 macrophage markers, upregulation of transforming growth factor-beta (TGF-β), TGF-β receptors and tight junction proteins, and reduction in BSCB permeability. These data suggest that release of sEVs by MSCs over time induces a cascade of cellular responses leading to improved functional recovery.

Effect of TO901317 on GF to promote the differentiation of human bone marrow mesenchymal stem cells into dopamine neurons on Parkinson's disease

Background:

Human bone marrow mesenchymal stem cells (hBMSCs) could differentiate into dopamine-producing cells and ameliorate behavioral deficits in Parkinson’s disease (PD) models. Liver X receptors (LXRs) are involved in the maintenance of the normal function of central nervous system myelin. Therefore, the previous work of our team has found the induction of cocktail-induced to dopaminergic (DA) phenotypes from adult rat BMSCs by using sonic hedgehog (SHH), fibroblast growth factor 8 (FGF8), basic fibroblast growth factor (bFGF), and TO901317 (an agonist of LXRs) with 87.42% of efficiency in a 6-day induction period. But we did not verify whether the induced cells had the corresponding neural function.

Methods:

Expressions of LXRα, LXRβ, and tyrosine hydroxylase (TH) were detected by immunofluorescence and western blot. Adenosine triphosphate-binding cassette transporter A1 (ABCA1) was detected by quantitative real-time PCR. The induced cells were transplanted into PD rats to study whether the induced cells are working.

Results:

The induced cells can release the dopamine transmitter; the maximum induction efficiency of differentiation of hBMSCs into DA neurons was 91.67% under conditions of combined use with TO901317 and growth factors (GF). When the induced-cells were transplanted into PD rats, the expression of TH in the striatum increased significantly, and the behavior of PD rats induced by apomorphine was significantly improved.

Conclusion:

The induced cells have the function of DA neurons and have the potential to treat PD. TO901317 promoted differentiation of hBMSCs into DA neurons, which may be related to activation of the LXR-ABCA1 signaling pathway.

Challenges and advances in clinical applications of mesenchymal stromal cells

Mesenchymal stromal cells (MSCs), also known as mesenchymal stem cells, have been intensely investigated for clinical applications within the last decades. However, the majority of registered clinical trials applying MSC therapy for diverse human diseases have fallen short of expectations, despite the encouraging pre-clinical outcomes in varied animal disease models. This can be attributable to inconsistent criteria for MSCs identity across studies and their inherited heterogeneity. Nowadays, with the emergence of advanced biological techniques and substantial improvements in bio-engineered materials, strategies have been developed to overcome clinical challenges in MSC application. Here in this review, we will discuss the major challenges of MSC therapies in clinical application, the factors impacting the diversity of MSCs, the potential approaches that modify MSC products with the highest therapeutic potential, and finally the usage of MSCs for COVID-19 pandemic disease.

Effect of Bone Marrow Stromal Cells in Parkinson's Disease Rodent Model: A Meta-Analysis

Background: Bone marrow stromal cells (BMSCs) has been reported to have beneficial effects in improving behavioral deficits, and rescuing dopaminergic neuron loss in rodent models of Parkinson's disease (PD). However, their pooled effects for dopaminergic neuron have yet to be described.

Objective: To review the neuroprotective effect of naïve BMSCs in rodent models of PD.

Methods: The PubMed, EMBASE, and Web of Science databases were searched up to September 30, 2020. Inclusion criteria according to PICOS criteria were as follows: (1) population: rodents; (2) intervention: unmodified BMSCs; (3) comparison: not specified; (4) primary outcome: tyrosine hydroxylase level in the substantia nigra pars compacta and rotational behavior; secondary outcome: rotarod test, and limb function; (5) study: experimental studies. Multiple prespecified subgroup and meta-regression analysis were conducted. Following quality assessment, random effects models were used for this meta-analysis.

Results: Twenty-seven animal studies were included. The median quality score was 4.7 (interquartile range, 2–8). Overall standardized mean difference between animals treated with naïve BMSCs and controls was 2.79 (95% confidence interval: 1.70, 3.87; P < 0.001) for densitometry of tyrosine hydroxylase-positive staining; −1.54 (95% confidence interval: −2.11, −0.98; P < 0.001) for rotational behavior. Significant heterogeneity among studies was observed.

Conclusions: Results of this meta-analysis suggest that naïve BMSCs therapy increased dopaminergic neurons and ameliorated behavioral deficits in rodent models of PD.

Autophagy: a promising therapeutic target for improving mesenchymal stem cell biological functions

Mesenchymal stem cells (MSCs) are considered to be a promising therapeutic material due to their capacities for self-renewal, multilineage differentiation, and immunomodulation and have attracted great attention in regenerative medicine. However, MSCs may lose their biological functions because of donor age or disease and environmental pressure before and after transplantation, which hinders the application of MSC-based therapy. As a major intracellular lysosome-dependent degradative process, autophagy plays a pivotal role in maintaining cellular homeostasis and withstanding environmental pressure and may become a potential therapeutic target for improving MSC functions. Recent studies have demonstrated that the regulation of autophagy is a promising approach for improving the biological properties of MSCs. More in-depth investigations about the role of autophagy in MSC biology are required to contribute to the clinical application of MSCs. In this review, we focus on the role of autophagy regulation by various physical and chemical factors on the biological functions of MSCs in vitro and in vivo, and provide some strategies for enhancing the therapeutic efficacy of MSCs.

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.

Mechanisms underlying the protective effects of mesenchymal stem cell-based therapy

Mesenchymal stem cells (MSCs) have been extensively investigated for the treatment of various diseases. The therapeutic potential of MSCs is attributed to complex cellular and molecular mechanisms of action including differentiation into multiple cell lineages and regulation of immune responses via immunomodulation. The plasticity of MSCs in immunomodulation allow these cells to exert different immune effects depending on different diseases. Understanding the biology of MSCs and their role in treatment is critical to determine their potential for various therapeutic applications and for the development of MSC-based regenerative medicine. This review summarizes the recent progress of particular mechanisms underlying the tissue regenerative properties and immunomodulatory effects of MSCs. We focused on discussing the functional roles of paracrine activities, direct cell-cell contact, mitochondrial transfer, and extracellular vesicles related to MSC-mediated effects on immune cell responses, cell survival, and regeneration. This will provide an overview of the current research on the rapid development of MSC-based therapies.

Influence of Bone Marrow-Derived Mesenchymal Stem Cell Therapy on Oxidative Stress Intensity in Minimally Conscious State Patients

Neurological disorders, including minimally conscious state (MCS), may be associated with the presence of high concentrations of reactive oxygen species within the central nervous system. Regarding the documented role of mesenchymal stem cells (MSCs) in oxidative stress neutralization, the aim of this study is to evaluate the effect of bone marrow-derived MSC (BM-MSC) transplantation on selected markers of oxidative stress in MCS patients. Antioxidant capacity was measured in cerebrospinal fluid (CSF) and plasma collected from nine patients aged between 19 and 45 years, remaining in MCS for 3 to 14 months. Total antioxidant capacity, ascorbic acid and ascorbate concentrations, superoxide dismutase, catalase, and peroxidase activity were analyzed and the presence of tested antioxidants in the CSF and plasma was confirmed. Higher ascorbic acid (AA) content and catalase (CAT) activity were noted in CSF relative to plasma, whereas superoxide dismutase (SOD) activity and total antioxidant capacity were higher in plasma relative to CSF. Total antioxidant capacity measured in CSF was greater after BM-MSC transplantations. The content of ascorbates was lower and CAT activity was higher both in CSF and plasma after the administration of BM-MSC. The above results suggest that MSCs modulate oxidative stress intensity in MCS patients, mainly via ascorbates and CAT activity.

Clinical potential and current progress of mesenchymal stem cells for Parkinson's disease: a systematic review

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease characterized by severe dyskinesia due to a progressive loss of dopaminergic neurons along the nigro-striatal pathway. The current focus of treatment is to relieve symptoms through administration of levodopa, such as L-3,4-dihydroxy phenylalanine replacement therapy, dopaminergic agonist administration, functional neurosurgery, and gene therapy, rather than preventing dopaminergic neuronal damage. Hence, the application and development of neuroprotective/disease modification strategies is absolutely necessary. Currently, stem cell therapy has been considered for PD treatment. As for the stem cells, mesenchymal stem cells (MSCs) seem to be the most promising. In this review, we analyze the mechanisms of action of MSCs in Parkinson's disease, including growth factor secretion, exocytosis, and attenuation of neuroinflammation. To determine efficacy and protect patients from possible adverse effects, ongoing rigorous and controlled studies of MSC treatment will be critical.

Mesenchymal stem cells in chemotherapy-induced peripheral neuropathy: A new challenging approach that requires further investigations

Chemotherapeutic drugs may disrupt the nervous system and cause chemotherapy-induced peripheral neuropathy (CIPN) as side effects. There are no completely successful medications for the prevention or treatment of CIPN. Many drugs such as tricyclic antidepressants and anticonvulsants have been used for symptomatic treatment of CIPN. Unfortunately, these drugs often give only partial relief or have dose-limiting side effects. Thus, the treatment of CIPN becomes a challenge because of failure to regenerate and repair the injured neurons. Mesenchymal stem cell (MSC) therapy is a new attractive approach for CIPN. Evidence has demonstrated that MSCs play important roles in reducing oxidative stress, neuroinflammation, and apoptosis, as well as mediating axon regeneration after nerve damage in several experimental studies and some clinical trials. We will briefly review the pathogenesis of CIPN, traditional therapies used and their drawbacks as well as therapeutic effects of MSCs, their related mechanisms, future challenges for their clinical application, and the additional benefit of their combination with pharmacological agents. MSCs-based therapies may provide a new therapeutic strategy for patients suffering from CIPN where further investigations are required for studying their exact mechanisms. Combined therapy with pharmacological agents can provide another promising option for enhancing MSC therapy success while limiting its adverse effects.

Mesenchymal Stromal Cell Therapies for Neurodegenerative Diseases

Mesenchymal stromal cells are multipotent cells that are being used to treat a variety of medical conditions. Over the past decade, there has been considerable excitement about using MSCs to treat neurodegenerative diseases, which are diseases that are typically fatal and without other robust therapies. In this review, we discuss the proposed MSC mechanisms of action in neurodegenerative diseases, which include growth factor secretion, exosome secretion, and attenuation of neuroinflammation. We then provide a summary of preclinical and early clinical work on MSC therapies in amyotrophic lateral sclerosis, multiple system atrophy, Parkinson disease, and Alzheimer disease. Continued rigorous and controlled studies of MSC therapies will be critical in order to establish efficacy and protect patients from possible untoward effects.

Secretome of Mesenchymal Stem Cells and Its Potential Protective Effects on Brain Pathologies

Previous studies have indicated that mesenchymal stem cells (MSCs) have a fundamental role in the repair and regeneration of damaged tissues. There is strong evidence showing that much of the beneficial effects of these cells are due to the secretion of bioactive molecules-besides microRNAs, hormones, and neurotrophins-with anti-inflammatory, immunoregulatory, angiogenic, and trophic effects. These factors have been reported by many studies to possess protective effects on the nervous tissue. Although the beneficial effects of the secretory factors of MSCs have been suggested for various neurological diseases, their actions on astrocytic cells are not well understood. Hence, it is important to recognize the specific effects of MSCs derived from adipose tissue, in addition to the differences presented by the secretome, depending on the source and methods of analysis. In this paper, the different sources of MSCs and their main characteristics are described, as well as the most significant advances in regeneration and protection provided by the secretome of MSCs. Also, we discuss the possible neuroprotective mechanisms of action of the MSC-derived biomolecules, with special emphasis on the effect of MSCs derived from adipose tissue and their impact on glial cells and brain pathologies.

Bone marrow-derived mesenchymal stem/stromal cells reverse the sensorial diabetic neuropathy via modulation of spinal neuroinflammatory cascades

BACKGROUND

Diabetic neuropathy (DN) is a frequent and debilitating manifestation of diabetes mellitus, to which there are no effective therapeutic approaches. Mesenchymal stem/stromal cells (MSC) have a great potential for the treatment of this syndrome, possibly through regenerative actions on peripheral nerves. Here, we evaluated the therapeutic effects of MSC on spinal neuroinflammation, as well as on ultrastructural aspects of the peripheral nerve in DN-associated sensorial dysfunction.

METHODS

C57Bl/6 mice were treated with bone marrow-derived MSC (1 × 10⁶), conditioned medium from MSC cultures (CM-MSC) or vehicle by endovenous route following the onset of streptozotocin (STZ)-induced diabetes. Paw mechanical and thermal nociceptive thresholds were evaluated by using von Frey filaments and Hargreaves test, respectively. Morphological and morphometric analysis of the sciatic nerve was performed by light microscopy and transmission electron microscopy. Mediators and markers of neuroinflammation in the spinal cord were measured by radioimmunoassay, real-time PCR, and immunofluorescence analyses.

RESULTS

Diabetic mice presented behavioral signs of sensory neuropathy, mechanical allodynia, and heat hypoalgesia, which were completely reversed by a single administration of MSC or CM-MSC. The ultrastructural analysis of the sciatic nerve showed that diabetic mice exhibited morphological and morphometric alterations, considered hallmarks of DN, such as degenerative changes in axons and myelin sheath, and reduced area and density of unmyelinated fibers. In MSC-treated mice, these structural alterations were markedly less commonly observed and/or less pronounced. Moreover, MSC transplantation inhibited multiple parameters of spinal neuroinflammation found in diabetic mice, causing the reduction of activated astrocytes and microglia, oxidative stress signals, galectin-3, IL-1β, and TNF-α production. Conversely, MSC increased the levels of anti-inflammatory cytokines, IL-10, and TGF-β.

CONCLUSIONS

The present study described the modulatory effects of MSC on spinal cord neuroinflammation in diabetic mice, suggesting new mechanisms by which MSC can improve DN.

Cell tracking, survival, and differentiation capacity of adipose-derived stem cells after engraftment in rat tissue

Adipose tissue is an important source of adipose derived stem cells (ADSCs). These cells have the potential of being used for certain therapies, in which the main objective is to recover the function of a tissue/organ affected by a disease. In order to contribute to repair of the tissue, these cells should be able to survive and carry out their functions in unfavorable conditions after being transplanted. This process requires a better understanding of the biology involved: such as the time cells remain in the implant site, how long they stay there, and whether or not they differentiate into host tissue cells. This report focuses on these questions. ADSC were injected into three different tissues (substantia nigra, ventricle, liver) and they were tracked in vivo with a dual GFP-Luc reporter system. The results show that ADSCs were able to survive up to 4 months after the engraftment and some of them started showing resident cell tissue phenotype. These results demonstrate their long-term capacity of survival and differentiation when injected in vivo.

From cord to caudate: characterizing umbilical cord blood stem cells and their paracrine interactions with the injured brain

Stem cells are proving to be a promising therapy for a wide range of pediatric disorders, from neonatal hypoxic-ischemic encephalopathy to pediatric leukemia. Owing to their low immunogenicity and ease of availability, umbilical cord blood (UCB) progenitor cells are increasingly replacing fetal- and adult-derived cells in therapeutic settings. Multiple environmental and demographic factors affect the number and type of stem cells extracted from UCB, and these differences have been associated with disparities in outcomes after transplantation. To avoid variations in efficacy, as well as the potential adverse effects of stem cell transplantation, evaluation of the stem cell secretome is critical to identify key paracrine signals released by the stem cells that could be used to provide similar neuroprotective effects to stem cell transplantation. This article describes the cell types found in UCB and reviews the available literature surrounding the effects of collection timing and volume, maternal risk factors, delivery characteristics, and neonatal demographics on the cellular composition of UCB. In addition, the current findings regarding the stem cell secretome are discussed to identify factors that could be used to supplement or replace stem cell transplantation in pediatric neuroprotection.

Reduced neuroprotective potential of the mesenchymal stromal cell secretome with ex vivo expansion, age and progressive multiple sclerosis

BACKGROUND

Clinical trials using ex vivo expansion of autologous mesenchymal stromal cells (MSCs) are in progress for several neurological diseases including multiple sclerosis (MS). Given that environment alters MSC function, we examined whether in vitro expansion, increasing donor age and progressive MS affect the neuroprotective properties of the MSC secretome.

METHODS

Comparative analyses of neuronal survival in the presence of MSC-conditioned medium (MSCcm) isolated from control subjects (C-MSCcm) and those with MS (MS-MSCcm) were performed following (1) trophic factor withdrawal and (2) nitric oxide-induced neurotoxicity.

RESULTS

Reduced neuronal survival following trophic factor withdrawal was seen in association with increasing expansion of MSCs in vitro and MSC donor age. Controlling for these factors, there was an independent, negative effect of progressive MS. In nitric oxide neurotoxicity, MSCcm-mediated neuroprotection was reduced when C-MSCcm was isolated from higher-passage MSCs and was negatively associated with increasing MSC passage number and donor age. Furthermore, the neuroprotective effect of MSCcm was lost when MSCs were isolated from patients with MS.

DISCUSSION

Our findings have significant implications for MSC-based therapy in neurodegenerative conditions, particularly for autologous MSC therapy in MS. Impaired neuroprotection mediated by the MSC secretome in progressive MS may reflect reduced reparative potential of autologous MSC-based therapy in MS and it is likely that the causes must be addressed before the full potential of MSC-based therapy is realized. Additionally, we anticipate that understanding the mechanisms responsible will contribute new insights into MS pathogenesis and may also be of wider relevance to other neurodegenerative conditions.

Hydrogels for central nervous system therapeutic strategies

The central nervous system shows a limited regenerative capacity, and injuries or diseases, such as those in the spinal, brain and retina, are a great problem since current therapies seem to be unable to achieve good results in terms of significant functional recovery. Different promising therapies have been suggested, the aim being to restore at least some of the lost functions. The current review deals with the use of hydrogels in developing advanced devices for central nervous system therapeutic strategies. Several approaches, involving cell-based therapy, delivery of bioactive molecules and nanoparticle-based drug delivery, will be first reviewed. Finally, some examples of injectable hydrogels for the delivery of bioactive molecules in central nervous system will be reported, and the key features as well as the basic principles in designing multifunctional devices will be described.

Mesenchymal stromal SB623 cell implantation mitigates nigrostriatal dopaminergic damage in a mouse model of Parkinson's disease

Regenerative medicine for the treatment of motor features in Parkinson's disease (PD) is a promising therapeutic option. Donor cells can simultaneously address multiple pathological mechanisms while responding to the needs of the host tissue. Previous studies have demonstrated that mesenchymal stromal cells (MSCs) promote recovery using various animal models of PD. SanBio Inc. has developed a novel cell type designated SB623, which are adult bone marrow-derived MSCs transfected with Notch intracellular domain. In this preclinical study, SB623 cells protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigrostriatal injury when transplanted unilaterally into C57BL/6 mouse striatum 3 days prior to toxin exposure. Specifically, mice with the SB623 cell transplants revealed significantly higher levels of striatal dopamine, tyrosine hydroxylase immunoreactivity and stereological nigral cell counts in the ipsilateral hemisphere vs vehicle-treated mice following MPTP administration. Interestingly, improvement in markers of striatal dopaminergic integrity was also noted in the contralateral hemisphere. These data indicate that MSCs transplantation, specifically SB623 cells, may represent a novel therapeutic option to ameliorate damage related to PD, not only at the level of striatal terminals (i.e. the site of implantation) but also at the level of the nigral cell body. Copyright © 2015 John Wiley & Sons, Ltd.

Mesenchymal stromal cells to halt the progression of type 1 diabetes?

No treatment to halt the progressive loss of insulin-producing beta-cells in type 1 diabetes mellitus has yet been clinically introduced. Strategies tested have at best only transiently preserved beta-cell function and in many cases with obvious side effects of drugs used. Several studies have suggested that mesenchymal stromal cells exert strong immunomodulatory properties with the capability to prevent or halt diabetes development in animal models of type 1 diabetes. A multitude of mechanisms has been forwarded to exert this effect. Recently, we translated this strategy into a first clinical phase I/IIa trial and observed no side effects, and preserved or even increased C-peptide responses to a mixed meal tolerance test during the first year after treatment. Future blinded, larger studies, with extended follow-up, are clearly of interest to investigate this treatment concept.

Paracrine mechanisms of mesenchymal stem cell-based therapy: current status and perspectives

Mesenchymal stem cells (MSCs) are one of a few stem cell types to be applied in clinical practice as therapeutic agents for immunomodulation and ischemic tissue repair. In addition to their multipotent differentiation potential, a strong paracrine capacity has been proposed as the principal mechanism that contributes to tissue repair. Apart from cytokine/chemokine secretion, MSCs also display a strong capacity for mitochondrial transfer and microvesicle (exosomes) secretion in response to injury with subsequent promotion of tissue regeneration. These unique properties of MSCs make them an invaluable cell type to repair damaged tissues/organs. Although MSCs offer great promise in the treatment of degenerative diseases and inflammatory disorders, there are still many challenges to overcome prior to their widespread clinical application. Particularly, their in-depth paracrine mechanisms remain a matter for debate and exploration. This review will highlight the discovery of the paracrine mechanism of MSCs, regulation of the paracrine biology of MSCs, important paracrine factors of MSCs in modulation of tissue repair, exosome and mitochondrial transfer for tissue repair, and the future perspective for MSC-based therapy.

Reductions in kinesin expression are associated with nitric oxide-induced axonal damage

Axonal injury is often characterized by axonal transport defects and abnormal accumulation of intra-axonal components. Nitric oxide (NO) has a key role in mediating inflammatory axonopathy in many neurodegenerative diseases, but little is known about how nitrosative/oxidative stress affects axonal transport or whether reductions in kinesin superfamily protein (KIF) expression correlate with axon pathology. KIFs are molecular motors that have a key role in axonal and dendritic transport, and impairment of these mechanisms has been associated with a number of neurological disorders. This study shows that rat cortical neurons exposed to NO display both a time-dependent decrease in KIF gene/protein expression and neurofilament phosphorylation in addition to a reduction in axonal length and neuronal survival. Because mesenchymal stem cells (MSCs) represent a promising therapeutic candidate for neuronal/axonal repair, this study analyzes the capacity of MSCs to protect neurons and axonal transport mechanisms from NO damage. Results show that coculture of MSCs with NO-exposed neurons results in the preservation of KIF expression, axonal length, and neuronal survival. Altogether, these results suggest a potential mechanism involved in the disruption of axonal transport and abnormal accumulation of proteins in axons during nitrosative insult. We hypothesize that impaired axonal transport contributes, per se, to progression of injury and provide further evidence of the therapeutic potential of MSCs for neurodegenerative disorders. © 2015 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc.

Mesenchymal stem cells support neuronal fiber growth in an organotypic brain slice co-culture model

Mesenchymal stem cells (MSCs) have been identified as promising candidates for neuroregenerative cell therapies. However, the impact of different isolation procedures on the functional and regenerative characteristics of MSC populations has not been studied thoroughly. To quantify these differences, we directly compared classically isolated bulk bone marrow-derived MSCs (bulk BM-MSCs) to the subpopulation Sca-1(+)Lin(-)CD45(-)-derived MSCs(-) (SL45-MSCs), isolated by fluorescence-activated cell sorting from bulk BM-cell suspensions. Both populations were analyzed with respect to functional readouts, that are, frequency of fibroblast colony forming units (CFU-f), general morphology, and expression of stem cell markers. The SL45-MSC population is characterized by greater morphological homogeneity, higher CFU-f frequency, and significantly increased nestin expression compared with bulk BM-MSCs. We further quantified the potential of both cell populations to enhance neuronal fiber growth, using an ex vivo model of organotypic brain slice co-cultures of the mesocortical dopaminergic projection system. The MSC populations were cultivated underneath the slice co-cultures without direct contact using a transwell system. After cultivation, the fiber density in the border region between the two brain slices was quantified. While both populations significantly enhanced fiber outgrowth as compared with controls, purified SL45-MSCs stimulated fiber growth to a larger degree. Subsequently, we analyzed the expression of different growth factors in both cell populations. The results show a significantly higher expression of brain-derived neurotrophic factor (BDNF) and basic fibroblast growth factor in the SL45-MSCs population. Altogether, we conclude that MSC preparations enriched for primary MSCs promote neuronal regeneration and axonal regrowth, more effectively than bulk BM-MSCs, an effect that may be mediated by a higher BDNF secretion.

Cell-based therapy for acute organ injury: preclinical evidence and ongoing clinical trials using mesenchymal stem cells

Critically ill patients often suffer from multiple organ failures involving lung, kidney, liver, or brain. Genomic, proteomic, and metabolomic approaches highlight common injury mechanisms leading to acute organ failure. This underlines the need to focus on therapeutic strategies affecting multiple injury pathways. The use of adult stem cells such as mesenchymal stem or stromal cells (MSC) may represent a promising new therapeutic approach as increasing evidence shows that MSC can exert protective effects following injury through the release of promitotic, antiapoptotic, antiinflammatory, and immunomodulatory soluble factors. Furthermore, they can mitigate metabolomic and oxidative stress imbalance. In this work, the authors review the biological capabilities of MSC and the results of clinical trials using MSC as therapy in acute organ injuries. Although preliminary results are encouraging, more studies concerning safety and efficacy of MSC therapy are needed to determine their optimal clinical use. (ANESTHESIOLOGY 2014; 121:1099-121).

ReNCell VM conditioned medium enhances the induction of dental pulp stem cells into dopaminergic like cells

Among the debilitating diseases, neurological related diseases are the most challenging ones to be treated using cell replacement therapies. Recently, dental pulp stem cells (SHED) were found to be most suitable cell choice for neurological related diseases as evidenced with many preclinical studies. To enhance the neurological potential of SHED, we recapitulated one of the pharmacological therapeutic tools in cell replacement treatment, we pre-conditioned dental pulp stem cells (SHED) with culture medium of ReNCell VM, an immortalized neuron progenitor cell, prior to neurogenesis induction and investigated whether this practice enhances their neurogenesis potential especially towards dopaminergic neurons. We hypothesed that the integration of pharmacological practices such as co-administration of various drugs, a wide range of doses and duration as well as pre-conditioning into cell replacement may enhance the efficacy of stem cell therapy. In particular, pre-conditioning is shown to be involved in the protective effect from some membrano-tropic drugs, thereby improving the resistance of cell structures and homing capabilities. We found that cells pre-treated with ReNCell VM conditioned medium displayed bipolar structures with extensive branches resembling putative dopaminergic neurons as compared to non-treated cells. Furthermore, many neuronal related markers such as NES, NR4A2, MSI1, and TH were highly expressed (fold changes > 2; p < 0.05) in pre-treated cells. Similar observations were detected at the protein level. The results demonstrate for the first time that SHED pre-conditioning enhances neurological potential and we suggest that cells should be primed to their respective environment prior to transplantation.

Intracerebral administration of ultrasound-induced dissolution of lipid-coated GDNF microbubbles provides neuroprotection in a rat model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by loss of dopaminergic neurons in the substantia nigra. Neurotrophic factors, such as glial cell derived neurotrophic factor (GDNF), have been shown to provide a neuroprotective effect in PD rats. We have previously reported that ultrasound-induced lipid-coated GDNF microspheres, which release GDNF in a sustained manner after low frequency ultrasound stimulation, can reduce hypoxic-ischemic injury in neonatal rats. In the present study, we investigated whether lipid-coated GDNF microspheres can provide a neuroprotective effect in a rat model of PD. After a rat model of PD was produced by 6-hydroxydompamine (6-OHDA) injections, lipid-coated GDNF microspheres (1.5mg/kg) were injected into the striatum of PD rats. We found that GDNF levels were increased in the striatum of PD rats after lipid-coated GDNF microspheres administration following low frequency ultrasound stimulation (20kHz, 5min per day, daily for 4 weeks). Moreover, GDNF microspheres reduced apomorphine-induced rotations, and increased striatal dopamine and nigral tyrosine hydroxylase (TH) levels in PD rats. Additionally, GDNF microspheres reduced caspase-3, tumor necrosis factor-alpha, matrix metalloproteinase 9 (MMP-9) and OX-6 levels induced by 6-OHDA injections in PD rats. These data indicated that lipid-coated GDNF microspheres can provide a neuroprotective effect in PD rats.

Hydrogel-based nanocomposites and mesenchymal stem cells: a promising synergistic strategy for neurodegenerative disorders therapy

Hydrogel-based materials are widely employed in the biomedical field. With regard to central nervous system (CNS) neurodegenerative disorders, the design of injectable nanocomposite hydrogels for in situ drug or cell release represents an interesting and minimally invasive solution that might play a key role in the development of successful treatments. In particular, biocompatible and biodegradable hydrogels can be designed as specific injectable tools and loaded with nanoparticles (NPs), to improve and to tailor their viscoelastic properties upon injection and release profile. An intriguing application is hydrogel loading with mesenchymal stem cells (MSCs) that are a very promising therapeutic tool for neurodegenerative or traumatic disorders of the CNS. This multidisciplinary review will focus on the basic concepts to design acellular and cell-loaded materials with specific and tunable rheological and functional properties. The use of hydrogel-based nanocomposites and mesenchymal stem cells as a synergistic strategy for nervous tissue applications will be then discussed.

Immunobiology of mesenchymal stem cells

Mesenchymal stem cells (MSCs) can be isolated from almost all tissues and effectively expanded in vitro. Although their true in situ properties and biological functions remain to be elucidated, these in vitro expanded cells have been shown to possess potential to differentiate into specific cell lineages. It is speculated that MSCs in situ have important roles in tissue cellular homeostasis by replacing dead or dysfunctional cells. Recent studies have demonstrated that in vitro expanded MSCs of various origins have great capacity to modulate immune responses and change the progression of different inflammatory diseases. As tissue injuries are often accompanied by inflammation, inflammatory factors may provide cues to mobilize MSCs to tissue sites with damage. Before carrying out tissue repair functions, MSCs first prepare the microenvironment by modulating inflammatory processes and releasing various growth factors in response to the inflammation status. In this review, we focus on the crosstalk between MSCs and immune responses and their potential clinical applications, especially in inflammatory diseases.

The neuroprotective effect exerted by oligodendroglial progenitors on ischemically impaired hippocampal cells

Oligodendrocyte progenitor cells (OPCs) are the focus of intense research for the purpose of cell replacement therapies in acquired or inherited neurodegenerative disorders, accompanied by ongoing hypo/demyelination. Recently, it has been postulated that these glia-committed cells exhibit certain properties of neural stem cells. Advances in stem cell biology have shown that their therapeutic effect could be attributed to their ability to secret numerous active compounds which modify the local microenvironment making it more susceptible to restorative processes. To verify this hypothesis, we set up an ex vivo co-culture system of OPCs isolated from neonatal rat brain with organotypic hippocampal slices (OHC) injured by oxygen-glucose deprivation (OGD). The presence of OPCs in such co-cultures resulted in a significant neuroprotective effect manifesting itself as a decrease in cell death rate and as an extension of newly formed cells in ischemically impaired hippocampal slices. A microarray analysis of broad spectrum of trophic factors and cytokines expressed by OPCs was performed for the purpose of finding the factor(s) contributing to the observed effect. Three of them—BDNF, IL-10 and SCF—were selected for the subsequent functional assays. Our data revealed that BDNF released by OPCs is the potent factor that stimulates cell proliferation and survival in OHC subjected to OGD injury. At the same time, it was observed that IL-10 attenuates inflammatory processes by promoting the formation of the cells associated with the immunological response. Those neuroprotective qualities of oligodendroglia-biased progenitors significantly contribute to anticipating a successful cell replacement therapy.

Inhibitory effect of carbazolequinone derivatives on lipopolysaccharide and interferon-γ-induced nitric oxide production in mouse macrophage RAW264.7 cells

Objectives

The aim of this study was to examine the mechanism underlying the inhibitory effect of our synthesized carbazolequinone derivatives on nitric oxide (NO) production in activated macrophages.

Methods

Lipopolysaccharide (LPS) and interferon-γ (IFN-γ)-stimulated RAW264.7 macrophages were treated with carbazolequinone derivatives. The NO and prostaglandin E2 (PGE2) levels in cell culture supernatants fractions were measured by Greiss and ELISA assay, respectively. The expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) was assessed by the real-time RT-PCR method. Nuclear factor kappa B (NF-κB) activation was detected by an NF-κB-dependent luciferase reporter assay.

Key findings

Our synthesized carbazolequinone derivatives (7-methoxy-2-methylcarbazole-1,4-quinone, 6-methoxy-2-methylcarbazole-1,4-quinone and 6-chloro-2-methylcarbazole-1,4-quinone) significantly inhibited LPS/IFN-γ-induced NO production and iNOS expression in RAW264.7 cells. They also inhibited the LPS/IFN-γ-mediated induction of COX-2 expression and PGE2 production. In addition, the LPS/IFN-γ-induced transcription activity of NF-κB was attenuated. Using the RAW264.7-tsAM5NE co-culture system, we found that these carbazolequinone derivatives protected neuronally differentiated tsAM5NE cells from NO-induced cell death by inhibiting the production of NO.

Conclusions

These results suggest that the three carbazolequinone derivatives inhibit LPS/IFN-γ-induced NO production via iNOS and COX-2 downregulation due to NF-κB inhibition. Therefore, these three carbazolequinone derivatives may be useful for developing a new drug against NO-mediated neurodegenerative diseases.

Human adipose tissue derived mesenchymal stem cells aggravate chronic cyclosporin nephrotoxicity by the induction of oxidative stress

The aim of this study was to investigate whether hATMSCs protect against cyclosporine (CsA)-induced renal injury. CsA (7.5 mg/kg) and hATMSCs (3×10⁶/5 mL) were administered alone and together to rats for 4 weeks. The effect of hATMSCs on CsA-induced renal injury was evaluated by assessing renal function, interstitial fibrosis, infiltration of inflammatory cells, and apoptotic cell death. Four weeks of CsA-treatment produced typical chronic CsA-nephropathy. Combined treatment with CsA and hATMSCs did not prevent these effects and showed a trend toward further renal deterioration. To evaluate why hATMSCs aggravated CsA-induced renal injury, we measured oxidative stress, a major mechanism of CsA-induced renal injury. Both urine and serum 8-hydroxydeoxyguanosine(8-OHdG) levels were higher in the CsA+hATMSCs group than in the CsA group (P<0.05). An in vitro study showed similar results. Although the rate of apoptosis did not differ significantly between HK-2 cells cultured in hATMSCs-conditioned medium and those cultured in DMEM, addition of CsA resulted in greater apoptosis in HK-2 cells cultured in hATMSCs-conditioned medium. Addition of CsA increased oxidative stress in the hATMSCs-conditioned medium. The results of our study suggest that treatment with hATMSCs may aggravate CsA-induced renal injury because hATMSCs cause oxidative stress in the presence of CsA.