Human mesenchymal stem cells efficiently manage oxidative stress

Current Development, Obstacle and Futural Direction of Induced Pluripotent Stem Cell and Mesenchymal Stem Cell Treatment in Degenerative Retinal Disease

Degenerative retinal disease is one of the major causes of vision loss around the world. The past several decades have witnessed emerging development of stem cell treatment for retinal disease. Nevertheless, sourcing stem cells remains controversial due to ethical concerns and their rarity. Furthermore, induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) are both isolated from patients’ mature tissues; thus, issues such as avoiding moral controversy and adverse events related to immunosuppression and obtaining a large number of cells have opened a new era in regenerative medicine. This review focuses on the current application and development, clinical trials, and latest research of stem cell therapy, as well as its limitations and future directions.

Emerging Trends in Mesenchymal Stem Cells Applications for Cardiac Regenerative Therapy: Current Status and Advances

Irreversible myocardium infarction is one of the leading causes of cardiovascular disease (CVD) related death and its quantum is expected to grow in coming years. Pharmacological intervention has been at the forefront to ameliorate injury-related morbidity and mortality. However, its outcomes are highly skewed. As an alternative, stem cell-based tissue engineering/regenerative medicine has been explored quite extensively to regenerate the damaged myocardium. The therapeutic modality that has been most widely studied both preclinically and clinically is based on adult multipotent mesenchymal stem cells (MSC) delivered to the injured heart. However, there is debate over the mechanistic therapeutic role of MSC in generating functional beating cardiomyocytes. This review intends to emphasize the role and use of MSC in cardiac regenerative therapy (CRT). We have elucidated in detail, the various aspects related to the history and progress of MSC use in cardiac tissue engineering and its multiple strategies to drive cardiomyogenesis. We have further discussed with a focus on the various therapeutic mechanism uncovered in recent times that has a significant role in ameliorating heart-related problems. We reviewed recent and advanced technologies using MSC to develop/create tissue construct for use in cardiac regenerative therapy. Finally, we have provided the latest update on the usage of MSC in clinical trials and discussed the outcome of such studies in realizing the full potential of MSC use in clinical management of cardiac injury as a cellular therapy module.

Combination Therapy of Metadichol Nanogel and Lipocalin-2 Engineered Mesenchymal Stem Cells Improve Wound Healing in Rat Model of Excision Injury

Purpose: Currently, several disorders including burns, trauma, excisional and diabetic wounds, and bedsores threaten the human health. Application of mesenchymal stem cells (MSCs) is recommended for treatment of skin disorders. However, because of oxidative stress and inflammation after skin injury, survival of transplanted MSCs is low which in turn negatively affects the efficiency of the MSCs-based therapy. In an attempt to address the aforementioned challenge and introducing a novel potential therapeutic strategy, we employed combination therapy by lipocalin 2 (Lcn2)-engineered MSCs and a Metadichol (an inverse agonist of vitamin D receptor (VDR)) nanogel in a rat model of excisional wound.

Methods: First, human umbilical cord MSCs (hUC-MSCs) was transfected by a recombinant plasmid encoding Lcn2 gene. Next, a combination of Metadichol nanogel and the engineered MSCs was co-applied on wound in rat model of excision injury. Finally the improvement of wound healing in experimental groups was evaluated by photography and histological assessments (hematoxylin and eosin staining).

Results: Our findings revealed that the repair rate was higher in the group received combination therapy comparing to control groups. Notably, Metadichol+Lcn2-MSCs showed significantly higher wound contraction rate compared to control group at all time points (P value < 0.001). Furthermore, wound repair rate was 95% 14 days after surgery, and 100% after 21 days in the treatment groups. Our results also revealed that the combination therapy improved and accelerated the wound healing process.

Conclusion: Our findings suggest a novel potential therapeutic strategy i.e. Lcn2-engineered MSCs and Metadichol for wound healing. However, further preclinical and clinical studies are required.

Regulation of pathophysiological and tissue regenerative functions of MSCs mediated via the WNT signaling pathway (Review)

Tissues have remarkable natural capabilities to regenerate for the purpose of physiological turnover and repair of damage. Adult mesenchymal stem cells (MSCs) are well known for their unique self-renewal ability, pluripotency, homing potential, paracrine effects and immunomodulation. Advanced research of the unique properties of MSCs have opened up new horizons for tissue regenerative therapies. However, certain drawbacks of the application of MSCs, such as the low survival rate of transplanted MSCs, unsatisfactory efficiency and even failure to regenerate under an unbalanced microenvironment, are concerning with regards to their wider therapeutic applications. The activity of stem cells is mainly regulated by the anatomical niche; where they are placed during their clinical and therapeutic applications. Crosstalk between various niche signals maintains MSCs in homeostasis, in which the WNT signaling pathway plays vital roles. Several external or internal stimuli have been reported to interrupt the normal bioactivity of stem cells. The irreversible tissue loss that occurs during infection at the site of tissue grafting suggests an inhibitory effect mediated by microbial infections within MSC niches. In addition, MSC-seeded tissue engineering success is difficult in various tissues, when sites of injury are under the effects of a severe infection despite the immunomodulatory properties of MSCs. In the present review, the current understanding of the way in which WNT signaling regulates MSC activity modification under physiological and pathological conditions was summarized. An effort was also made to illustrate parts of the underlying mechanism, including the inflammatory factors and their interactions with the regulatory WNT signaling pathway, aiming to promote the clinical translation of MSC-based therapy.

Transplantation of Umbilical Cord-Derived Mesenchymal Stem Cells Overexpressing Lipocalin 2 Ameliorates Ischemia-Induced Injury and Reduces Apoptotic Death in a Rat Acute Myocardial Infarction Model

Myocardial infarction (MI) is a leading cause of death worldwide and requires development of efficient therapeutic strategies . Mesenchymal stem cells (MSCs) -based therapy of MI has been promising but inefficient due to undesirable microenvironment of the infarct tissue. Hence, the current study was conducted to fortify MSCs against the unfavorable microenvironment of infarct tissue via overexpression of Lipocalin 2 (Lcn2) as a cytoprotective factor. The engineered cells (Lcn2-MSCs) were transplanted to infarcted heart of a rat model of MI. According to our findings, Lcn2 overexpression resulted in increased MSCs survival in the MI tissue (p < 0.05) compared to non-engineered cells. Furthermore, the infusion of Lcn2-MSCs mitigated Left ventricle (LV) remodeling, decreased fibrosis (p < 0.0001), and reduced apoptotic death of the LVs' cells (p < 0.0001) compared to the control. Our findings suggest a potential novel therapeutic strategy for MI, however, further investigations such as safety and efficacy assessments in large animals followed by clinical trials are required.

Photobiomodulation of mineralisation in mesenchymal stem cells

Mesenchymal stem cells (MSCs) and photobiomodulation (PBM) both offer significant therapeutic potential in regenerative medicine. MSCs have the ability to self-renew and differentiate; giving rise to multiple cellular and tissue lineages that are utilised in repair and regeneration of damaged tissues. PBM utilises light energy delivered at a range of wavelengths to promote wound healing. The positive effects of light on MSC proliferation are well documented; and recently, several studies have determined the outcomes of PBM on mineralised tissue differentiation in MSC populations. As PBM effects are biphasic, it is important to understand the underlying cellular regulatory mechanisms, as well as, provide accurate details of the irradiation conditions, to optimise and standardise outcomes. This review article focuses on the use of red, near-infra-red (R/NIR) and blue wavelengths to promote the mineralisation potential of MSCs; and also reports on the possible molecular mechanisms which underpin transduction of these effects. A variety of potential photon absorbers have been identified which are reported to mediate the signalling mechanisms, including respiratory chain enzymes, flavins, and cryptochromes. Studies report that R/NIR and blue light stimulate MSC differentiation by enhancing respiratory chain activity and increasing reactive oxygen species levels; however, currently, there are considerable variations between irradiation parameters reported. We conclude that due to its non-invasive properties, PBM may, following optimisation, provide an efficient therapeutic approach to clinically support MSC-mediated hard tissue repair. However, to optimise application, further studies are required to identify appropriate light delivery parameters, as well as elucidate the photo-signalling mechanisms involved.

Optimization of oxidative stress for mesenchymal stromal/stem cell engraftment, function and longevity

Mesenchymal stromal/stem cells (MSCs) are multipotent cells that possess great potential as a cellular therapeutic based on their ability to differentiate to different lineages and to modulate immune responses. However, their potential is limited by their low tissue abundance, and thus the need for robust ex vivo expansion prior to their application. This creates its own issues, namely replicative senescence, which could lead to reduced MSC functionality and negatively impact their engraftment. Ex vivo expansion and MSC aging are associated with greater oxidative stress. Therefore, there is great need to identify strategies to reduce oxidative stress in MSCs. This review summarizes the achievements made to date in addressing oxidative stress in MSCs and speculates about interesting avenues of future investigation to solve this critical problem.

MSCs and Inflammatory Cells Crosstalk in Regenerative Medicine: Concerted Actions for Optimized Resolution Driven by Energy Metabolism

Mesenchymal stromal cells (MSCs) are currently widely used in cell based therapy regarding to their remarkable efficacy in controlling the inflammatory status in patients. Despite recent progress and encouraging results, inconstant therapeutic benefits are reported suggesting that significant breakthroughs in the understanding of MSCs immunomodulatory mechanisms of action remains to be investigated and certainly apprehended from original point of view. This review will focus on the recent findings regarding MSCs close relationship with the innate immune compartment, i.e. granulocytes and myeloid cells. The review will also consider the intercellular mechanism of communication involved, such as factor secretion, cell-cell contact, extracellular vesicles, mitochondria transfer and efferocytosis. Immune-like-properties of MSCs supporting part of their therapeutic effect in the clinical setting will be discussed, as well as their potentials (immunomodulatory, anti-bacterial, anti-inflammatory, anti-oxidant defenses and metabolic adaptation…) and effects mediated, such as cell polarization, differentiation, death and survival on various immune and tissue cell targets determinant in triggering tissue regeneration. Their metabolic properties in term of sensing, reacting and producing metabolites influencing tissue inflammation will be highlighted. The review will finally open to discussion how ongoing scientific advances on MSCs could be efficiently translated to clinic in chronic and age-related inflammatory diseases and the current limits and gaps that remain to be overcome to achieving tissue regeneration and rejuvenation.

Heterospheroid formation improves therapeutic efficacy of mesenchymal stem cells in murine colitis through immunomodulation and epithelial regeneration

Tissue repairing capacity and immunomodulatory effects of mesenchymal stem cells (MSCs) have been extensively utilized for treating various inflammatory disorders; however, inconsistent efficacy and therapeutic outcomes due to low survival rate after transplantation often restrain their clinical potential. To overcome these limitations, 3-dimensional culture (3D-culture) was established to augment stemness and paracrine functions of MSCs, although hypoxic stress at the core often leads to unexpected cell death. Thus, we designed a novel strategy to improve the microenvironment of MSCs by creating heterospheroids (HS) consisting of MSCs and quercetin (QUR)-loaded microspheres (MSCHS), to achieve local drug delivery to the cells. Notably, MSCHS exhibited resistance for senescence-associated phenotype and oxidative stress-induced apoptosis compared to 3D-cultured MSCs (MSC3D), as well as to 2D-cultured cells (MSC2D) in vitro. In a murine model of colitis, MSC3D and MSCHS exhibited enhanced anti-inflammatory impact than MSC2Dvia attenuating neutrophil infiltration and regulating helper T cell (Th) polarization into Th1 and Th17 cells. Interestingly, MSCHS provided better therapeutic outcomes compared to MSC3D, partially due to their enhanced survival capacity in vivo. Moreover, we found that MSC-derived paracrine factor, prostaglandin E2 (PGE2), can directly drive the epithelial regeneration process by inducing specialized tissue-repairing cell generation using the intestinal organoid culture. Importantly, MSC3D and MSCHS displayed an outstanding regeneration-inducing potency compared to MSC2D owing to their superior PGE2 secretion. Taken together, we suggest a convergent strategy of MSCHS formation with reactive oxygen species (ROS) scavenger, QUR, which can maximize the inflammation-attenuating and tissue-repairing capacity of MSCs, as well as the engraftment efficiency after transplantation.

Mesenchymal Stem Cells as a Cornerstone in a Galaxy of Intercellular Signals: Basis for a New Era of Medicine

Around 40% of the population will suffer at some point in their life a disease involving tissue loss or an inflammatory or autoimmune process that cannot be satisfactorily controlled with current therapies. An alternative for these processes is represented by stem cells and, especially, mesenchymal stem cells (MSC). Numerous preclinical studies have shown MSC to have therapeutic effects in different clinical conditions, probably due to their mesodermal origin. Thereby, MSC appear to play a central role in the control of a galaxy of intercellular signals of anti-inflammatory, regenerative, angiogenic, anti-fibrotic, anti-oxidative stress effects of anti-apoptotic, anti-tumor, or anti-microbial type. This concept forces us to return to the origin of natural physiological processes as a starting point to understand the evolution of MSC therapy in the field of regenerative medicine. These biological effects, demonstrated in countless preclinical studies, justify their first clinical applications, and draw a horizon of new therapeutic strategies. However, several limitations of MSC as cell therapy are recognized, such as safety issues, handling difficulties for therapeutic purposes, and high economic cost. For these reasons, there is an ongoing tendency to consider the use of MSC-derived secretome products as a therapeutic tool, since they reproduce the effects of their parent cells. However, it will be necessary to resolve key aspects, such as the choice of the ideal type of MSC according to their origin for each therapeutic indication and the implementation of new standardized production strategies. Therefore, stem cell science based on an intelligently designed production of MSC and or their derivative products will be able to advance towards an innovative and more personalized medical biotechnology.

Stem Cell Therapy Offers a Possible Safe and Promising Alternative Approach for Treating Vitiligo: A Review

BACKGROUND

Normal skin pigmentation pattern is an extremely important component of the appearance of a person, as it can be a significant factor in the social context of any person. A condition known as vitiligo is caused by the death of melanocytes leading to pigmentation loss in the skin. This affects all races across the globe and sometimes leads to social avoidance as in some communities, it is stigmatized. Although there are different pathobiological processes suspected because of the different underlying causes of vitiligo, autoimmunity and oxidative stress are suspected to be the most probable ones.

OBJECTIVE

In this review, we present an overview of the underlying mechanisms causing and developing the disease. Also, some of the most successful treatments along with the clinical applications of Mesenchymal Stem Cells (MSCs) as a comprehensive approach for treating this condition will be covered.

RESULTS

Autoreactive CD8+ T-cells are the primary suspect considered to be responsible for the destruction of melanocytes. Therefore, topical use of autoimmune inhibitors including those derived from MSCs, thanks to their immune-modulatory properties, have been reported to be successful in the promotion of repigmentation. MSCs can suppress the proliferation of CD8+T via the NKG2D pathway while inducing T-cell apoptosis. The use of pharmacological agents for reducing cellular oxidative stress with the help of topical application of antioxidants and growth factors also have been in use. Intravenous administration of MSCs has been shown to regulate the level of reactive oxidative species (ROS) in a mice model. Growth factors derived from platelet-rich-plasma (PRP) or from MSCs caused rapid tissue regeneration.

CONCLUSIONS

Finally, MSC therapy also has been shown to stimulate the mobilization of healthy melanocytes, leading to successful repigmentation of skin lesions in vitiligo patients.

Discrepancies on the Role of Oxygen Gradient and Culture Condition on Mesenchymal Stem Cell Fate

Over the past few years, mesenchymal stem (or stromal) cells (MSCs) have garnered enormous interest due to their therapeutic value especially for their multilineage differentiation potential leading to regenerative medicine applications. MSCs undergo physiological changes upon in vitro expansion resulting in expression of different receptors, thereby inducing high variabilities in therapeutic efficacy. Therefore, understanding the biochemical cues that influence the native local signals on differentiation or proliferation of these cells is very important. There have been several reports that in vitro culture of MSCs in low oxygen gradient (or hypoxic conditions) upregulates the stemness markers and promotes cell proliferation in an undifferentiated state, as hypoxia mimics the conditions the progenitor cells experience within the tissue. However, different studies report different oxygen gradients and culture conditions causing ambiguity in their interpretation of the results. In this progress report, it is aimed to summarize recent studies in the field with specific focus on conflicting results reported during the application of hypoxic conditions for improving the proliferation or differentiation of MSCs. Further, it is tried to decipher the factors that can affect characteristics of MSC under hypoxia and suggest a few techniques that could be combined with hypoxic cell culture to better recapitulate the MSC tissue niche.

Biological characteristics of stem cells derived from burned skin-a comparative study with umbilical cord stem cells

INTRODUCTION

Burned human skin, which is routinely excised and discarded, contains viable mesenchymal stromal/stem cells (burn-derived mesenchymal stromal/stem cells; BD-MSCs). These cells show promising potential to enable and aid wound regeneration. However, little is known about their cell characteristics and biological function.

OBJECTIVES

This study had two aims: first, to assess critical and cellular characteristics of BD-MSCs and, second, to compare those results with multipotent well-characterized MSCs from Wharton's jelly of human umbilical cords (umbilical cord mesenchymal stromal/stem cells, UC-MSCs).

METHODS

BD- and UC-MSCs were compared using immunophenotyping, multi-lineage differentiation, seahorse analysis for glycolytic and mitochondrial function, immune surface markers, and cell secretion profile assays.

RESULTS

When compared to UC-MSCs, BD-MSCs demonstrated a lower mesenchymal differentiation capacity and altered inflammatory cytokine secretomes at baseline and after stimulation with lipopolysaccharides. No significant differences were found in population doubling time, colony formation, cell proliferation cell cycle, production of reactive oxygen species, glycolytic and mitochondrial function, and in the expression of major histocompatibility complex I and II and toll-like receptor (TLR).

IMPORTANCE, TRANSLATION

This study reveals valuable insights about MSCs obtained from burned skin and show comparable cellular characteristics with UC-MSCs, highlighting their potentials in cell therapy and skin regeneration.

Differential SOD2 and GSTZ1 profiles contribute to contrasting dental pulp stem cell susceptibilities to oxidative damage and premature senescence

Background

Dental pulp stem cells (DPSCs) are increasingly being advocated as viable cell sources for regenerative medicine-based therapies. However, significant heterogeneity in DPSC expansion and multi-potency capabilities are well-established, attributed to contrasting telomere profiles and susceptibilities to replicative senescence. As DPSCs possess negligible human telomerase (hTERT) expression, we examined whether intrinsic differences in the susceptibilities of DPSC sub-populations to oxidative stress-induced biomolecular damage and premature senescence further contributed to this heterogeneity, via differential enzymic antioxidant capabilities between DPSCs.

Methods

DPSCs were isolated from human third molars by differential fibronectin adhesion, and positive mesenchymal (CD73/CD90/CD105) and negative hematopoietic (CD45) stem cell marker expression confirmed. Isolated sub-populations were expanded in H₂O₂ (0–200 μM) and established as high or low proliferative DPSCs, based on population doublings (PDs) and senescence (telomere lengths, SA-β-galactosidase, p53/p16^INK4a/p21^waf1/hTERT) marker detection. The impact of DPSC expansion on mesenchymal, embryonic, and neural crest marker expression was assessed, as were the susceptibilities of high and low proliferative DPSCs to oxidative DNA and protein damage by immunocytochemistry. Expression profiles for superoxide dismutases (SODs), catalase, and glutathione-related antioxidants were further compared between DPSC sub-populations by qRT-PCR, Western blotting and activity assays.

Results

High proliferative DPSCs underwent > 80PDs in culture and resisted H₂O₂₋induced senescence (50–76PDs). In contrast, low proliferative sub-populations exhibited accelerated senescence (4–32PDs), even in untreated controls (11-34PDs). While telomere lengths were largely unaffected, certain stem cell marker expression declined with H₂O₂ treatment and expansion. Elevated senescence susceptibilities in low proliferative DPSC (2–10PDs) were accompanied by increased oxidative damage, absent in high proliferative DPSCs until 45–60PDs. Increased SOD2/glutathione S-transferase ζ1 (GSTZ1) expression and SOD activities were identified in high proliferative DPSCs (10–25PDs), which declined during expansion. Low proliferative DPSCs (2–10PDs) exhibited inferior SOD, catalase and glutathione-related antioxidant expression/activities.

Conclusions

Significant variations exist in the susceptibilities of DPSC sub-populations to oxidative damage and premature senescence, contributed to by differential SOD2 and GSTZ1 profiles which maintain senescence-resistance/stemness properties in high proliferative DPSCs. Identification of superior antioxidant properties in high proliferative DPSCs enhances our understanding of DPSC biology and senescence, which may be exploited for selective sub-population screening/isolation from dental pulp tissues for regenerative medicine-based applications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02209-9.

Intercellular mitochondrial transfer as a means of tissue revitalization

As the crucial powerhouse for cell metabolism and tissue survival, the mitochondrion frequently undergoes morphological or positional changes when responding to various stresses and energy demands. In addition to intracellular changes, mitochondria can also be transferred intercellularly. Besides restoring stressed cells and damaged tissues due to mitochondrial dysfunction, the intercellular mitochondrial transfer also occurs under physiological conditions. In this review, the phenomenon of mitochondrial transfer is described according to its function under both physiological and pathological conditions, including tissue homeostasis, damaged tissue repair, tumor progression, and immunoregulation. Then, the mechanisms that contribute to this process are summarized, such as the trigger factors and transfer routes. Furthermore, various perspectives are explored to better understand the mysteries of cell-cell mitochondrial trafficking. In addition, potential therapeutic strategies for mitochondria-targeted application to rescue tissue damage and degeneration, as well as the inhibition of tumor progression, are discussed.

Therapeutic potential of stem cells for preterm infant brain damage: Can we move from the heterogeneity of preclinical and clinical studies to established therapeutics?

Acquired perinatal brain injuries are a set of conditions that remains a key challenge for neonatologists and that have significant social, emotional and financial implications for our communities. In our perspective article, we will introduce perinatal brain injury focusing specifically on the events leading to brain damage in preterm born infants and outcomes for these infants. Then we will summarize and discuss the preclinical and clinical studies testing the efficacy of stem cells as neuroprotectants in the last ten years in perinatal brain injury. There are no therapies to treat brain damage in preterm born infants and a primary finding from this review is that there is a scarcity of stem cell trials focused on overcoming brain injuries in these infants. Overall, across all forms of perinatal brain injury there is a remarkable heterogeneity in previous and on-going preclinical and clinical studies in terms of the stem cell type, animal models/patient selection, route and time of administration. Despite the quality of many of the studies this variation makes it difficult to reach a valid consensus for future developments. However, it is clear that stem cells (and stem cell derived exosomes) can reduce perinatal brain injury and our field needs to work collectively to refine an effective protocol for each type of injury. The use of standardized stem cell products and testing these products across multiple models of injury will provide a stronger framework for clinical trials development.

Reestablishment of Redox Homeostasis in the Nociceptive Primary Afferent as a Mechanism of Antinociception Promoted by Mesenchymal Stem/Stromal Cells in Oxaliplatin-Induced Chronic Peripheral Neuropathy

Painful neuropathy is a common adverse effect of oxaliplatin (OXL), a platinum-derivative chemotherapeutic agent. Oxidative stress and mitochondrial dysfunction are key factors contributing to the development of OXL-induced peripheral neuropathy (OIPN). Based on the antioxidant and antinociceptive properties of mesenchymal stem/stromal cells (MSC), the present study tested the hypothesis that MSC induce antinociceptive effects during OIPN by promoting regulation of redox environment and mitochondrial homeostasis in the nociceptive primary afferents. C57Bl/6 mice submitted to the OXL-chronic neuropathy induction protocol by repeated intravenous administration of OXL (1 mg/kg) were evaluated to determine the paw mechanical and thermal nociceptive thresholds using the von Frey filaments and cold plate tests, respectively. Two weeks after the neuropathy induction, mice were treated with bone marrow-derived MSC (1 × 106), vehicle, or gabapentin (GBP, 70 mg/kg). Four weeks later, mitochondrial morphology, gene expression profile, and oxidative stress markers in the sciatic nerve and dorsal root ganglia (DRG) were evaluated by transmission electron microscopy, RT-qPCR, and biochemical assays, respectively. OXL-treated mice presented behavioral signs of sensory neuropathy, such as mechanical allodynia and thermal hyperalgesia. The behavioral painful neuropathy was completely reverted by a single administration of MSC, while the daily treatment with GBP induced only a short-lived antinociceptive effect. The ultrastructural analysis of the sciatic nerve and DRG of OIPN mice revealed a high proportion of atypical mitochondria in both myelinated and unmyelinated fibers. Importantly, this mitochondrial atypia was strongly reduced in MSC-treated neuropathic mice. Moreover, MSC-treated neuropathic mice showed upregulation of Sod and Nrf2 mRNA in the sciatic nerve and DRG. In line with this result, MSC reduced markers of nitrosative stress and lipid peroxidation in the sciatic nerve and DRG from OIPN mice. Our data suggest that the reestablishment of redox homeostasis in the nociceptive primary afferents is a mechanism by which MSC transplantation reverts the OXL-induced chronic painful neuropathy.

Antiobesity Effects of Adipose-Derived Stromal/Stem Cells in a Naturally Aged Mouse Model

OBJECTIVE

Adipose-derived stromal/stem cells (ASCs) have multilineage differentiation potential and functional properties, as well as applications for cell-based therapies in tissue repair and regeneration. However, there is a lack of evidence regarding the efficacy of ASCs as an antiobesity agent in aged organisms. This study aimed to clarify the effectiveness of ASCs at treating obesity using a naturally aged mouse model.

METHODS

Old (22 months) C57BL/6J mice with transplanted young-mice (2 months) donor ASCs were measured for weight change, biochemistry, cytokines, hormone secretion, cell senescence, lipid metabolism, and functional changes of ASCs.

RESULTS

The results indicated that old mice treated with ASCs showed antiaging and antiobesity effects such as significant loss of body and organ weight, improved stem cell plasticity, increased antioxidant capacity (superoxide dismutase and catalase), improved liver and kidney function, improved lipid metabolism, and increased hormone secretion (sex hormone-binding globulin, thyrotropin, and leptin). Treatment with ASCs decreased cell senescence and suppressed secretion of inflammatory agents (interleukin-6 and tumor necrosis factor alpha).

CONCLUSIONS

Traditional drugs used in the treatment of obesity have limitations and are unsuitable for the elderly. Based on the results, the future use of ASCs as primary antiaging and antiobesity agents is suggested because of their positive effects on aged animals.

Mesenchymal Stem Cell Transplantation for the Treatment of Cognitive Frailty

As life expectancy increases, frailty and cognitive impairment have become major factors influencing healthy aging in elderly individuals. Frailty is a complicated clinical condition characterized by decreased physiological reserve and multisystem abnormalities. Cognitive frailty is a subtype of frailty that has aroused widespread concern among the scientific community and public health organizations. We herein review the pathogenesis of cognitive frailty, such as chronic inflammatory response, immunological hypofunction, imbalanced oxidative stress, reduced regenerative function, endocrine dysfunction, and energy metabolism disorder. Although existing interventions show some therapeutic effects, they do not meet the current clinical needs. To date, studies using stem cell technology for treating age-related diseases have achieved remarkable success. This suggests the possibility of applying stem cell treatment to cognitive frailty. We analyzed stem cell-based strategies for targeting anti-inflammation, antioxidation, regeneration, and immunoregulation using mesenchymal stem cells, as well as potential therapeutic targets for cognitive frailty. Based on this investigation, we propose a highly effective and low-cost stem cell-based replacement strategy. However, there is a lack of comprehensive research on the prospect of stem cell transplantation for improving cognitive frailty. In this review, we aim to provide the scientific background and a theoretical basis for testing cell therapy in future research.

Effect of Age and Lipoperoxidation in Rat and Human Adipose Tissue-Derived Stem Cells

A wide range of clinical applications in regenerative medicine were opened decades ago with the discovery of adult stem cells. Highly promising adult stem cells are mesenchymal stem/stromal cells derived from adipose tissue (ADSCs), primarily because of their abundance and accessibility. These cells have multipotent properties and have been used extensively to carry out autologous transplants. However, the biology of these cells is not entirely understood. Among other factors, the regeneration capacity of these cells will depend on both their capacity of proliferation/differentiation and the robustness of the biochemical pathways that allow them to survive under adverse conditions like those found in damaged tissues. The transcription factors, such as Nanog and Sox2, have been described as playing an important role in stem cell proliferation and differentiation. Also, the so-called longevity pathways, in which AMPK and SIRT1 proteins play a crucial role, are essential for cell homeostasis under stressful situations. These pathways act by inhibiting the translation through downregulation of elongation factor-2 (eEF2). In order to deepen knowledge of mesenchymal stem cell biology and which factors are determinant in the final therapeutic output, we evaluate in the present study the levels of all of these proteins in the ADSCs from humans and rats and how these levels are affected by aging and the oxidative environment. Due to the effect of aging and oxidative stress, our results suggest that before performing a cell therapy with ADSCs, several aspects reported in this study such as oxidative stress status and proliferation and differentiation capacity should be assessed on these cells. This would allow us to know the robustness of the transplanted cells and to predict the therapeutic result, especially in elder patients, where probably ADSCs do not carry out their biological functions in an optimal way.

Herb-Derived Products: Natural Tools to Delay and Counteract Stem Cell Senescence

Cellular senescence plays a very important role in organismal aging increasing with age and in age-related diseases (ARDs). This process involves physiological, structural, biochemical, and molecular changes of cells, leading to a characteristic trait referred to "senescence-associated secretory phenotype (SASP)." In particular, with aging, stem cells (SCs) in situ exhibit a diminished capacity of self-renewal and show a decline in their functionality. The identification of interventions able to prevent the accumulation of senescent SCs in the organism or to pretreat cultured multipotent mesenchymal stromal cells (MSCs) prior to employing them for cell therapy is a main purpose of medical research. Many approaches have been investigated and resulted effective to prevent or counteract SC senescence in humans, as well as other animal models. In this work, we have reviewed the chance of using a number of herb-derived products as novel tools in the treatment of cell senescence, highlighting the efficacy of these agents, often still far from being clearly understood.

Immunomodulatory and Antioxidative potentials of adipose-derived Mesenchymal stem cells isolated from breast versus abdominal tissue: a comparative study

BACKGROUND

Adipose-derived stem cells (ASCs) are considered ideal candidates for both research and cellular therapy due to ease of access, large yield, feasibility, and efficacy in preclinical and clinical studies. Unlike the subcutaneous abdominal fat depot, breast ASCs features are still not well recognized, limiting their possible therapeutic use. ASCs were found to exert immunomodulatory and antioxidative activities for maintaining homeostasis and functionality of diseased/damaged tissues. This study aims to investigate the immunomodulatory and antioxidative potentials of breast versus abdominal isolated ASCs to find out which anatomical site provides ASCs with better immunoregulatory and oxidative stress resistance capabilities.

METHODS

ASCs were isolated from abdominal and breast tissues. Gene expression analysis was conducted for a panel of immunomodulatory and antioxidative genes, as well as adipokines and proliferation genes. Flow cytometric analysis of a group of immunomodulatory surface proteins was also performed. Finally, the significantly expressed genes have undergone protein-protein interaction and functional enrichment in silico analyses.

RESULTS

Our results revealed similar morphological and phenotypic characteristics for both breast and abdominal ASCs. However, a significant elevation in the expression of two potent immunosuppressive genes, IL-10 and IDO as well as the expression of the multifaceted immunomodulatory adipokine, visfatin, was detected in breast versus abdominal ASCs. Moreover, a significant overexpression of the antioxidative genes, GPX1, SIRT5, and STAT3 and the proliferation marker, Ki67, was also observed in breast ASCs relative to abdominal ones. In silico analysis showed that both of the differentially upregulated immunomodulatory and antioxidative mediators integratively involved in multiple biological processes and pathways indicating their functional association.

CONCLUSION

Breast ASCs possess superior immunomodulatory and antioxidative capabilities over abdominal ASCs. Our findings shed light on the possible therapeutic applications of breast ASCs in immune-related and oxidative stress-associated diseases.

Long-isoform NRF1 protects against arsenic cytotoxicity in mouse bone marrow-derived mesenchymal stem cells by suppressing mitochondrial ROS and facilitating arsenic efflux

Acute exposure to arsenic is known to cause bone marrow depression and result in anemia, in which the dusfunction of cells in the bone marrow niche such as mesenchymal stem cells (MSCs) is vital. However, the mechanism underlying response of MSCs to arsenic challange is not fully understood. In the present study, we investigated the role of nuclear factor erythroid 2-related factor (NRF) 1 (NRF1), a sister member of the well-known master regulator in antioxidative response NRF2, in arsenite-induced cytotoxicity in mouse bone marrow-derived MSCs (mBM-MSCs). We found that arsenite exposure induced significant increase in the protein level of long-isoform NRF1 (L-NRF1). Though short-isoform NRF1 (S-NRF1) was induced by arsenite at mRNA level, its protein level was not obviously altered. Silencing L-Nrf1 sensitized the cells to arsenite-induced cytotoxicity. L-Nrf1-silenced mBM-MSCs showed decreased arsenic efflux with reduced expression of arsenic transporter ATP-binding cassette subfamily C member 4 (ABCC4), as well as compromised NRF2-mediated antioxidative defense with elevated level of mitochondrial reactive oxygen species (mtROS) under arsenite-exposed conditions. A specific mtROS scavenger (Mito-quinone) alleviated cell apoptosis induced by arsenite in L-Nrf1-silenced mBM-MSCs. Taken together, these findings suggest that L-NRF1 protects mBM-MSCs from arsenite-induced cytotoxicity via suppressing mtROS in addition to facilitating cellular arsenic efflux.

Mesenchymal Stromal Cells as Critical Contributors to Tissue Regeneration

Adult stem cells that are tightly regulated by the specific microenvironment, or the stem cell niche, function to maintain tissue homeostasis and regeneration after damage. This demands the existence of specific niche components that can preserve the stem cell pool in injured tissues and restore the microenvironment for their subsequent appropriate functioning. This role may belong to mesenchymal stromal cells (MSCs) due to their resistance to damage signals and potency to be specifically activated in response to tissue injury and promote regeneration by different mechanisms. Increased amount of data indicate that activated MSCs are able to produce factors such as extracellular matrix components, growth factors, extracellular vesicles and organelles, which transiently substitute the regulatory signals from missing niche cells and restrict the injury-induced responses of them. MSCs may recruit functional cells into a niche or differentiate into missing cell components to endow a niche with ability to regulate stem cell fates. They may also promote the dedifferentiation of committed cells to re-establish a pool of functional stem cells after injury. Accumulated evidence indicates the therapeutic promise of MSCs for stimulating tissue regeneration, but the benefits of administered MSCs demonstrated in many injury models are less than expected in clinical studies. This emphasizes the importance of considering the mechanisms of endogenous MSC functioning for the development of effective approaches to their pharmacological activation or mimicking their effects. To achieve this goal, we integrate the current ideas on the contribution of MSCs in restoring the stem cell niches after damage and thereby tissue regeneration.

Human Wharton's jelly mesenchymal stem cells protect neural cells from oxidative stress through paracrine mechanisms

Aim

Mesenchymal stem cells (MSCs) have neuroprotective and immunomodulatory properties, which are partly mediated by extracellular vesicles (EVs) secretion. We aimed to evaluate the effects of human Wharton's jelly-derived MSCs (WJ-MSCs) and their EVs on rat hippocampal cultures subjected to hydrogen peroxide (H₂O₂).

Materials & methods

Hippocampal dissociated cultures were either co-cultured with WJ-MSCs or treated with their EVs prior to H₂O₂ exposure and reactive oxygen species levels and cell viability were evaluated.

Results

Coculture with WJ-MSCs or pre-incubation with EVs prior to the insult reduced reactive oxygen species after H₂O₂ exposure. Cell viability was improved only when coculture was maintained following the insult, while EVs did not significantly improve cell viability.

Conclusion

WJ-MSCs have potential antioxidant and neuroprotective effects on hippocampal cultures which might be partially mediated by EVs.

Therapeutic Potential of Mesenchymal Stem Cells for Postmastectomy Lymphedema: A Literature Review

Upper limb lymphedema is one of the most common complications after breast cancer surgery and radiotherapy. Despite various physical therapy and surgical options available, the impaired lymph fluid drainage may be progressive due to lymphatic vascular insufficiency making treatment more difficulty. Stem cell therapy provides a promising alternative in the treatment of various chronic diseases. The wide applicability of cell therapy has been reviewed throughout literature. This review provides an overview of recent progress in the therapeutic effect of adult stem cells for primary and secondary lymphedema after breast surgery in preclinical studies and clinical cases. We start with a brief introduction about the pathophysiological mechanisms of postmastectomy lymphedema. Regarding existing treatments, we systematically summarize the benefits and limitations of recent progress. Because of their multidirectional differentiation potential and growth factor secretion, stem cell therapy shows promising results in the management of light to severe lymphedema. Increasing evidences have demonstrated a noticeable reduction in postmastectomy lymphedema and increased lymph-angiogenesis after specific stem cell therapy. Current data suggests that stem cell therapy in lymphedema treatment provides reversal of pathological reorganization associated with lymphedema progression. Finally, we propose potential strategies for overcoming the challenges in the development of multipotent progenitor cells for the treatment and prevention of lymphedema in clinical practice.

Dental Pulp Mesenchymal Stem Cells as a Treatment for Periodontal Disease in Older Adults

Periodontal disease (PD) is one of the main causes of tooth loss and is related to oxidative stress and chronic inflammation. Although different treatments have been proposed in the past, the vast majority do not regenerate lost tissues. In this sense, the use of dental pulp mesenchymal stem cells (DPMSCs) seems to be an alternative for the regeneration of periodontal bone tissue. A quasi-experimental study was conducted in a sample of 22 adults between 55 and 64 years of age with PD, without uncontrolled systemic chronic diseases. Two groups were formed randomly: (i) experimental group (EG) n = 11, with a treatment based on DPMSCs; and a (ii) control group (CG) n = 11, without a treatment of DPMSCs. Every participant underwent clinical and radiological evaluations and measurement of bone mineral density (BMD) by tomography. Saliva samples were taken as well, to determine the total concentration of antioxidants, superoxide dismutase (SOD), lipoperoxides, and interleukins (IL), before and 6 months after treatment. All subjects underwent curettage and periodontal surgery, the EG had a collagen scaffold treated with DPMSCs, while the CG only had the collagen scaffold placed. The EG with DPMSCs showed an increase in the BMD of the alveolar bone with a borderline statistical significance (baseline 638.82 ± 181.7 vs. posttreatment 781.26 ± 162.2 HU, p = 0.09). Regarding oxidative stress and inflammation markers, salivary SOD levels were significantly higher in EG (baseline 1.49 ± 0.96 vs. 2.14 ± 1.12 U/L posttreatment, p < 0.05) meanwhile IL1β levels had a decrease (baseline 1001.91 ± 675.5vs. posttreatment 722.3 ± 349.4 pg/ml, p < 0.05). Our findings suggest that a DPMSCs treatment based on DPMSCs has both an effect on bone regeneration linked to an increased SOD and decreased levels of IL1β in aging subjects with PD.

H2O2-preconditioned human adipose-derived stem cells (HC016) increase their resistance to oxidative stress by overexpressing Nrf2 and bioenergetic adaptation

BACKGROUND

Mesenchymal stem cells, including those derived from human adipose tissue (hASCs), are currently being widely investigated for cell therapy. However, when transplanted at the site of injury, the survival and engraftment rates of hASCs are low, mainly due to the harsh microenvironment they encounter, characterized by inflammation and oxidative stress. To overcome these therapeutic limitations, cell preconditioning with low-concentration of hydrogen peroxide (H2O2) has been proposed as a plausible strategy to increase their survival and adaptation to oxidative stress. Nonetheless, the underlying mechanisms of this approach are not yet fully understood. In this study, we analyzed molecular and bioenergetic changes that take place in H2O2 preconditioned hASCs.

METHODS

Long-term exposure to a low concentration of H2O2 was applied to obtain preconditioned hASCs (named HC016), and then, their response to oxidative stress was analyzed. The effect of preconditioning on the expression of Nrf2 and its downstream antioxidant enzymes (HO-1, SOD-1, GPx-1, and CAT), and of NF-κB and its related inflammatory proteins (COX-2 and IL-1β), were examined by Western blot. Finally, the Seahorse XF96 Flux analysis system was used to evaluate the mitochondrial respiration and glycolytic function, along with the total ATP production.

RESULTS

We found that under oxidative conditions, HC016 cells increased the survival by (i) decreasing intracellular ROS levels through the overexpression of the transcription factor Nrf2 and its related antioxidant enzymes HO-1, SOD-1, GPx-1, and CAT; (ii) reducing the secretion of pro-inflammatory molecules COX-2 and IL-1β through the attenuation of the expression of NF-κB; and (iii) increasing the total ATP production rate through the adaption of their metabolism to meet the energetic demand required to survive.

CONCLUSIONS

H2O2 preconditioning enhances hASC survival under oxidative stress conditions by stimulating their antioxidant response and bioenergetic adaptation. Therefore, this preconditioning strategy might be considered an excellent tool for strengthening the resistance of hASCs to harmful oxidative stress.

Continuous Exposure to 1.7 GHz LTE Electromagnetic Fields Increases Intracellular Reactive Oxygen Species to Decrease Human Cell Proliferation and Induce Senescence

Due to the rapid development of mobile phone technology, we are continuously exposed to 1.7 GHz LTE radio frequency electromagnetic fields (RF-EMFs), but their biological effects have not been clarified. Here, we investigated the non-thermal cellular effects of these RF-EMFs on human cells, including human adipose tissue-derived stem cells (ASCs), Huh7 and Hep3B liver cancer stem cells (CSCs), HeLa and SH-SY5Y cancer cells, and normal fibroblast IMR-90 cells. When continuously exposed to 1.7 GHz LTE RF-EMF for 72 h at 1 and 2 SAR, cell proliferation was consistently decreased in all the human cells. The anti-proliferative effect was higher at 2 SAR than 1 SAR and was less severe in ASCs. The exposure to RF-EMF for 72 h at 1 and 2 SAR did not induce DNA double strand breaks or apoptotic cell death, but did trigger a slight delay in the G1 to S cell cycle transition. Cell senescence was also clearly observed in ASC and Huh7 cells exposed to RF-EMF at 2 SAR for 72 h. Intracellular ROS increased in these cells and the treatment with an ROS scavenger recapitulated the anti-proliferative effect of RF-EMF. These observations strongly suggest that 1.7 GHz LTE RF-EMF decrease proliferation and increase senescence by increasing intracellular ROS in human cells.

Comparative Analysis of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells between Preeclampsia and Normal Pregnant Women

Preeclampsia is a syndrome characterized by deterioration of either the maternal condition or the fetal condition. The adverse intrauterine environment made by preeclampsia results into intrauterine growth restriction and increased risk of a variety of diseases in future life. Given the adverse environment of fetal circulation made in the preeclamptic condition, and the role of mesenchymal stem cell (MSC) as a multipotent progenitor cell, we hypothesized that MSCs derived from human umbilical cord blood (hUCB-MSCs) obtained from preeclampsia are adversely altered or affected compared with normal pregnancy. The aim of this study was to analyze the biological characteristics and compare the functional abilities and gene expression patterns of hUCB-MSCs originating from pregnant women with and without severe preeclampsia. hUCB-MSCs were isolated and cultured from 28 pregnant women with severe preeclampsia and 30 normal pregnant women. hUCB-MSCs obtained from women with preeclampsia were less proliferative and more senescent and had lower telomerase activity and higher ROS activity than cells from women with normal pregnancy. In addition, many senescence-related differentially expressed genes (DEGs) were identified by analysis of microarray gene expression profiles and significantly associated with the Gene Ontology term cell aging. In conclusion, hUCB-MSCs obtained from women with preeclampsia showed the poorly proliferative, more senescent, and decreased telomerase activity, and these characters may be related with functional impairment of MSC from preeclampsia compared with cells from normal pregnancy.

The emerging antioxidant paradigm of mesenchymal stem cell therapy

Mesenchymal stem cells (multipotent stromal cells; MSCs) have been under investigation for the treatment of diverse diseases, with many promising outcomes achieved in animal models and clinical trials. The biological activity of MSC therapies has not been fully resolved which is critical to rationalizing their use and developing strategies to enhance treatment efficacy. Different paradigms have been constructed to explain their mechanism of action, including tissue regeneration, trophic/anti-inflammatory secretion, and immunomodulation. MSCs rarely engraft and differentiate into other cell types after in vivo administration. Furthermore, it is equivocal whether MSCs function via the secretion of many peptide/protein ligands as their therapeutic properties are observed across xenogeneic barriers, which is suggestive of mechanisms involving mediators conserved between species. Oxidative stress is concomitant with cellular injury, inflammation, and dysregulated metabolism which are involved in many pathologies. Growing evidence supports that MSCs exert antioxidant properties in a variety of animal models of disease, which may explain their cytoprotective and anti-inflammatory properties. In this review, evidence of the antioxidant effects of MSCs in in vivo and in vitro models is explored and potential mechanisms of these effects are discussed. These include direct scavenging of free radicals, promoting endogenous antioxidant defenses, immunomodulation via reactive oxygen species suppression, altering mitochondrial bioenergetics, and donating functional mitochondria to damaged cells. Modulation of the redox environment and oxidative stress by MSCs can mediate their anti-inflammatory and cytoprotective properties and may offer an explanation to the diversity in disease models treatable by MSCs and how these mechanisms may be conserved between species.

Biocompatibility of Bone Marrow-Derived Mesenchymal Stem Cells in the Rat Inner Ear following Trans-Tympanic Administration

Recent advancements in stem cell therapy have led to an increased interest within the auditory community in exploring the potential of mesenchymal stem cells (MSCs) in the treatment of inner ear disorders. However, the biocompatibility of MSCs with the inner ear, especially when delivered non-surgically and in the immunocompetent cochlea, is not completely understood. In this study, we determined the effect of intratympanic administration of rodent bone marrow MSCs (BM-MSCs) on the inner ear in an immunocompetent rat model. The administration of MSCs did not lead to the generation of any oxidative stress in the rat inner ear. There was no significant production of proinflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-12, due to BM-MSCs administration into the rat cochlea. BM-MSCs do not activate caspase 3 pathway, which plays a central role in sensory cell damage. Additionally, transferase dUTP nick end labeling (TUNEL) staining determined that there was no significant cell death associated with the administration of BM-MSCs. The results of the present study suggest that trans-tympanic administration of BM-MSCs does not result in oxidative stress or inflammatory response in the immunocompetent rat cochlea.

Cardiac tissue remodeling in healthy aging: the road to pathology

This review aims to highlight the normal physiological remodeling that occurs in healthy aging hearts, including changes that occur in contractility, conduction, valve function, large and small coronary vessels, and the extracellular matrix. These "normal" age-related changes serve as the foundation that supports decreased plasticity and limited ability for tissue remodeling during pathophysiological states such as myocardial ischemia and heart failure. This review will identify populations at greater risk for poor tissue remodeling in advanced age along with present and future therapeutic strategies that may ameliorate dysfunctional tissue remodeling in aging hearts.

Cytoprotective effects of antioxidant supplementation on mesenchymal stem cell therapy

Mesenchymal stem cells (MSCs) are earmarked as perfect candidates for cell therapy and tissue engineering due to their capacity to differentiate into different cell types. However, their potential for application in regenerative medicine declines when the levels of the reactive oxygen and nitrogen species (RONS) increase from the physiological levels, a phenomenon which is at least inevitable in ex vivo cultures and air-exposed damaged tissues. Increased levels of RONS can alter the patterns of osteogenic and adipogenic differentiation and inhibit proliferation, as well. Besides, oxidative stress enhances senescence and cell death, thus lowering the success rates of the MSC engraftment. Hence, in this review, we have selected some representatives of antioxidants and newly emerged nano antioxidants in three main categories, including chemical compounds, biometabolites, and protein precursors/proteins, which are proved to be effective in the treatment of MSCs. We will focus on how antioxidants can be applied to optimize the clinical usage of the MSCs and their associated signaling pathways. We have also reviewed several paralleled properties of some antioxidants and nano antioxidants which can be simultaneously used in real-time imaging, scaffolding techniques, and other applications in addition to their primary antioxidative function.

Human Tonsil-Derived Mesenchymal Stromal Cells Maintain Proliferating and ROS-Regulatory Properties via Stanniocalcin-1

Mesenchymal stromal cells (MSCs) from various sources exhibit different potential for stemness and therapeutic abilities. Recently, we reported a unique MSCs from human palatine tonsil (TMSCs) and their superior proliferation capacity compared to MSCs from other sources. However, unique characteristics of each MSC are not yet precisely elucidated. We investigated the role of stanniocalcin-1 (STC1), an anti-oxidative hormone, in the functions of TMSCs. We found that STC1 was highly expressed in TMSC compared with MSCs from bone marrow or adipose tissue. The proliferation, senescence and differentiation of TMSCs were assessed after the inhibition of STC1 expression. STC1 inhibition resulted in a significant decrease in the proliferation of TMSCs and did not affect the differentiation potential. To reveal the anti-oxidative ability of STC1 in TMSCs themselves or against other cell types, the generation of mitochondrial reactive oxygen species (ROS) in TMSC or ROS-mediated production of interleukin (IL)-1β from macrophage-like cells were detected. Interestingly, the basal level of ROS generation in TMSCs was significantly elevated after STC1 inhibition. Moreover, down-regulation of STC1 impaired the inhibitory effect of TMSCs on IL-1β production in macrophages. Taken together, these findings indicate that STC1 is highly expressed in TMSCs and plays a critical role in proliferating and ROS-regulatory abilities.

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.

Downregulation of MicroRNA-206 Alleviates the Sublethal Oxidative Stress-Induced Premature Senescence and Dysfunction in Mesenchymal Stem Cells via Targeting Alpl

Bone marrow-derived mesenchymal stem cells (MSCs) have shown great promise in tissue engineering and regenerative medicine; however, the regenerative capacity of senescent MSCs is greatly reduced, thus exhibiting limited therapy potential. Previous studies uncovered that microRNA-206 (miR-206) could largely regulate cell functions, including cell proliferation, survival, and apoptosis, but whether miR-206 is involved in the senescent process of MSCs remains unknown. In this study, we mainly elucidated the effects of miR-206 on MSC senescence and the underlying mechanism. We discovered that miR-206 was upregulated in the senescent MSCs induced by H₂O₂, and abrogation of miR-206 could alleviate this tendency. Besides, we determined that by targeting Alpl, miR-206 could ameliorate the impaired migration and paracrine function in MSCs reduced by H₂O₂. In vivo study, we revealed that inhibition of miR-206 in senescent MSCs could effectively protect their potential for myocardial infarction treatment in a rat MI model. In summary, we examined that inhibition of miR-206 in MSCs can alleviate H₂O₂-induced senescence and dysfunction, thus protecting its therapeutic potential.

Antioxidant Properties of Tonsil-Derived Mesenchymal Stem Cells on Human Vocal Fold Fibroblast Exposed to Oxidative Stress

The therapeutic potential of tonsil-derived mesenchymal stem cells (TMSCs) has been proved in several in vitro and in vivo models based on their antioxidative capacity. Oxidative stress is involved in the formation of vocal fold scars and the aging of vocal folds. However, few studies have examined the direct correlation between oxidative damage and reconstitution of extracellular matrix (ECM) in the vocal fold fibrosis. We, therefore, sought to investigate the impact of oxidative stress on cell survival and ECM production of human vocal fibroblasts (hVFFs) and the protective effects elicited by TMSCs against oxidative damages in hVFFs. hVFFs were exposed to different concentrations of tert-butyl hydroperoxide in the presence or absence of TMSCs. Cell viability and reactive oxygen species (ROS) production were assessed to examine the progression of oxidative stress in vitro. In addition, expression patterns of ECM-associated factors including various collagens were examined by real-time PCR and immunocytochemical analysis. We found that both cell viability and proliferation capacity of hVFFs were decreased following the exposure to tBHP in a dose-dependent manner. Furthermore, tBHP treatment induced the generation of ROS and reactive aldehydes, while it decreased endogenous activity of antioxidant enzymes in hVFF. Importantly, TMSCs could rescue these oxidative stress-associated damages of hVFFs. TMSCs also downregulated tBHP-mediated production of proinflammatory cytokines in hVFFs. In addition, coculture with TMSC could restore the endogenous matrix metalloproteinase (MMP) activity of hVFFs upon tBHP treatment and, in turn, reduce the oxidative stress-induced ECM accumulation in hVFFs. We have, therefore, shown that the changes in hVFF proliferative capacity and ECM gene expression induced by oxidative stress are consistent with in vivo phenotypes observed in aging vocal folds and vocal fold scarring and that TMSCs may function to reduce oxidative stress in aging vocal folds.

Mesenchymal stem cells promote human melanocytes proliferation and resistance to apoptosis through PTEN pathway in vitiligo

Background

Vitiligo is an acquired chronic and recurrent skin disease that causes a depigmentation disorder, resulting in selective destruction of melanocytes (MC). However, the mechanism that leads to melanocyte dysfunction and death remains unclear.

Methods

We performed RNA sequencing, immunohistochemistry, and immunoblotting to characterize the patterns of phosphatase and tensin homolog (PTEN)/phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) pathway activation in vitiligo. We also cocultured primary melanocytes with mesenchymal stem cells (MSCs) in a Transwell system to explore how MSCs inhibit the PTEN/PI3K/AKT pathway in melanocytes.

Results

We identified that vitiligo normal-lesional junction skin presented with high expression of PTEN, which led to the inhibition of AKT phosphorylation (p-AKT) at S^-473. Furthermore, PTEN overexpression led to oxidative stress-induced apoptosis in melanocytes. Coculturing with MSCs enhanced the cell proliferation of human melanocytes and repressed PTEN expression, which inhibited oxidative stress-induced apoptosis.

Conclusion

We report that vitiligo patients present with high PTEN expression, which may play a role in the impairment of melanocytes. Furthermore, our study provides evidence that MSCs target the PTEN/PI3K/AKT pathway to regulate cell proliferation and apoptosis in human melanocytes, indicating that MSCs may serve as a promising therapy for vitiligo.

Human mesenchymal stem cells are resistant to UV-B irradiation

Albeit being an effective therapy for various cutaneous conditions, UV-B irradiation can cause severe skin damage. While multipotent mesenchymal stem cells (MSCs) may aid the regeneration of UV-B-induced skin injuries, the influence of UV-B irradiation on MSCs remains widely unknown. Here, we show that human MSCs are relatively resistant to UV-B irradiation compared to dermal fibroblasts. MSCs exhibited higher clonogenic survival, proliferative activity and viability than dermal fibroblasts after exposure to UV-B irradiation. Cellular adhesion, morphology and expression of characteristic surface marker patterns remained largely unaffected in UV-irradiated MSCs. The differentiation ability along the adipogenic, osteogenic and chondrogenic lineages was preserved after UV-B treatment. However, UV-B radiation resulted in a reduced ability of MSCs and dermal fibroblasts to migrate. MSCs exhibited low apoptosis rates after UV-B irradiation and repaired UV-B-induced cyclobutane pyrimidine dimers more efficiently than dermal fibroblasts. UV-B irradiation led to prolonged p53 protein stability and increased p21 protein expression resulting in a prolonged G2 arrest and senescence induction in MSCs. The observed resistance may contribute to the ability of these multipotent cells to aid the regeneration of UV-B-induced skin injuries.

Intrarenal Transplantation of Hypoxic Preconditioned Mesenchymal Stem Cells Improves Glomerulonephritis through Anti-Oxidation, Anti-ER Stress, Anti-Inflammation, Anti-Apoptosis, and Anti-Autophagy

To confer further therapeutic potential and prevent some adverse effects by the mesenchymal stem cells (MSCs) transplantation, we explored the effects of locally intrarenal arterial administration of hypoxic preconditioned MSCs in the anti-Thy1.1 induced rat glomerulonephritis. Proteinuria, histochemical staining, and western blotting were used to explore the therapeutic effects and mechanisms. Locally intrarenal arterial MSCs transplantation successfully implanted the fluorescent or CD44 labeled MSCs in the nephritic glomeruli, ameliorated proteinuria, and glomerulosclerosis in nephritic rats. Hypoxic preconditioning significantly upregulated hypoxic inducible factor-1α/VEGF (HIF-1α/VEGF) in the MSCs and was more efficient than normoxic MSCs in reducing the degree of urinary protein, glomerulosclerosis, fibrosis, macrophage/monocyte infiltration, GRP78 mediated endoplasmic reticulum stress, Beclin-1/LC3-II mediated autophagy, and Bax/Bcl-2/caspase 3 mediated apoptosis. Hypoxic MSCs could further promote intranuclear nuclear factor (erythroid-derived 2, Nrf2) and reduce nuclear factor kappa B expression in nephritic kidneys. As compared to normoxic MSCs, hypoxic MSCs transplantation significantly upregulated the renal expression of anti-oxidative response elements/enzymes including glutamate-cysteine ligase catalytic subunit, glutamate-cysteine ligase modifier subunit, glutathione peroxidase, catalase, Mn, and Cu/Zn superoxide dismutase. In summary, intrarenal hypoxic preconditioning MSCs transplantation was more effective to activate hypoxic inducible factor-1α/VEGF/Nrf2 (HIF-1α/VEGF/Nrf2) signaling, preserve anti-oxidant proteins and anti-oxidative responsive element proteins, and subsequently reduce glomerular apoptosis, autophagy, and inflammation.

Current understanding of the administration of mesenchymal stem cells in acute kidney injury to chronic kidney disease transition: a review with a focus on preclinical models

Incomplete recovery from acute kidney injury (AKI) can result in long-term functional deficits and has been recognized as a major contributor to chronic kidney disease (CKD), which is termed the AKI-CKD transition. Currently, an effective intervention for this disorder is still lacking. Principally, therapeutic strategies targeting the AKI-CKD transition can be divided into those reducing the severity of AKI or promoting the regenerative process towards beneficially adaptive repair pathways. Considering the fact that mesenchymal stem cells (MSCs) have the potential to address both aspects, therapeutic regimens based on MSCs have a promising future. In light of this information, we focus on the currently available evidence associated with MSC therapy involved in the treatment of the AKI-CKD transition and the underlying mechanisms. All of these discussions will contribute to the establishment of a reliable therapeutic strategy for patients with this problem, who can be easily ignored by physicians, and will lead to a better clinical outcome for them.

Radiation Responses of Human Mesenchymal Stem Cells Derived From Different Sources

Mesenchymal stem cells (MSCs) derived from different tissues may aid in the regeneration of radiation-induced organ lesions; however, the radiation responses of human MSCs from different sources are unknown. In our study, a comparison of the results from cell proliferation, apoptosis, cell cycle, DNA damage, and DNA repair assays consistently showed that MSCs derived from adipose tissue possess a significantly stronger radiation resistance capacity than MSCs derived from umbilical cord and gingival, which is accompanied by a higher level of phosphorylated signal transducer and activator of transcription 3 (Stat3) expression. This reminds us Stat3 could be a potential biomarker of radiation resistance. These findings provide a better understanding of radiation-induced biologic responses in MSCs and may lead to the development of better strategies for stem cell treatment and cancer therapy.

The Effect of Human Umbilical Cord Mesenchymal Stromal Cells in Protection of Dopaminergic Neurons from Apoptosis by Reducing Oxidative Stress in the Early Stage of a 6-OHDA-Induced Parkinson's Disease Model

Oxidative stress is an important cause of dopaminergic (DA) neuron apoptosis in Parkinson’s disease (PD). Mesenchymal stromal cells (MSCs) possess antioxidative features. In this study, we investigated whether MSCs could reduce oxidative stress and protect DA neurons from apoptosis by intravenous (I.V.) injection in the early stage of a 6-hydroxydopamine (6-OHDA)-induced PD model. MSCs were injected into the tail vein of mice, and behavioral tests, immunofluorescence staining, western blot, and oxidative stress levels were assessed at different time points. After 6-OHDA exposure, DA neuron apoptosis was detected, together with severe oxidative stress in brain and periphery. Compared with the non-transplanted sham controls, motor function in the 6-OHDA-lesioned group after I.V. injection of MSCs was significantly improved, and the levels of DA neuron apoptosis and oxidative stress decreased. The results demonstrate that MSCs can rescue DA neurons from ongoing apoptosis by reducing oxidative stress, and provide insights on developing new therapeutic strategies to offset the degenerative process of PD.

Extracellular vesicles derived from human Wharton's jelly mesenchymal stem cells protect hippocampal neurons from oxidative stress and synapse damage induced by amyloid-β oligomers

Background

Mesenchymal stem cells (MSCs) have been explored as promising tools for treatment of several neurological and neurodegenerative diseases. MSCs release abundant extracellular vesicles (EVs) containing a variety of biomolecules, including mRNAs, miRNAs, and proteins. We hypothesized that EVs derived from human Wharton’s jelly would act as mediators of the communication between hMSCs and neurons and could protect hippocampal neurons from damage induced by Alzheimer’s disease-linked amyloid beta oligomers (AβOs).

Methods

We isolated and characterized EVs released by human Wharton’s jelly mesenchymal stem cells (hMSC-EVs). The neuroprotective action of hMSC-EVs was investigated in primary hippocampal cultures exposed to AβOs.

Results

hMSC-EVs were internalized by hippocampal cells in culture, and this was enhanced in the presence of AβOs in the medium. hMSC-EVs protected hippocampal neurons from oxidative stress and synapse damage induced by AβOs. Neuroprotection by hMSC-EVs was mediated by catalase and was abolished in the presence of the catalase inhibitor, aminotriazole.

Conclusions

hMSC-EVs protected hippocampal neurons from damage induced by AβOs, and this was related to the transfer of enzymatically active catalase contained in EVs. Results suggest that hMSC-EVs should be further explored as a cell-free therapeutic approach to prevent neuronal damage in Alzheimer’s disease.

Intraportally delivered stem cell spheroids localize in the liver and protect hepatocytes against GalN/LPS-induced fulminant hepatic toxicity

BACKGROUND

Systemic inflammatory response syndrome (SIRS) is common in severe fulminant hepatic failure (FHF) and has a high mortality rate (20-50%) due to irreversible cerebral edema or sepsis. Stem cell-based treatment has emerged as a promising alternative therapeutic strategy to prolong the survival of patients suffering from FHF via the inhibition of SIRS due to their immunomodulatory effects.

METHODS

3D spheroids of adipose-derived mesenchymal stem cells (3D-ADSC) were prepared by the hanging drop method. The efficacy of the 3D-ADSC to rescue FHF was evaluated in a D-galactosamine/lipopolysaccharide (GalN/LPS)-induced mouse model of FHF via intraportal transplantation of the spheroids.

RESULTS

Intraportally delivered 3D-ADSC better engrafted and localized into the damaged livers compared to 2D-cultured adipose-derived mesenchymal stem cells (2D-ADSC). Transplantation of 3D-ADSC rescued 50% of mice from FHF-induced lethality, whereas only 20% of mice survived when 2D-ADSC were transplanted. The improved transplantation outcomes correlated with the enhanced immunomodulatory effect of 3D-ADSC in the liver microenvironment.

CONCLUSION

The study shows that the transplantation of optimized 3D-ADSC can efficiently ameliorate GalN/LPS-induced FHF due to improved viability, resistance to exogenous ROS, and enhanced immunomodulatory effects of 3D-ADSC.