Priming with Toll-like receptor 3 agonist or interferon-gamma enhances the therapeutic effects of human mesenchymal stem cells in a murine model of atopic dermatitis

Activation of Toll-like receptor 2 promotes mesenchymal stem/stromal cell-mediated immunoregulation and angiostasis through AKR1C1

Background: Mesenchymal stem/stromal cells (MSCs) maintain tissue homeostasis in response to microenvironmental perturbations. Toll-like receptors (TLRs) are key sensors for exogenous and endogenous signals produced during injury. In this study, we aimed to investigate whether TLRs affect the homeostatic functions of MSCs after injury. Methods: We examined the expression of TLR2, TLR3 and TLR4 in MSCs, and analyzed the functional significance of TLR2 activation using single-cell RNA sequencing. Additionally, we investigated the effects and mechanisms of TLR2 and its downstream activation in MSCs on the MSCs themselves, on monocytes/macrophages, and in a mouse model of sterile injury-induced inflammatory corneal angiogenesis. Results: MSCs expressed TLR2, which was upregulated by monocytes/macrophages. Activation of TLR2 in MSCs promoted their immunoregulatory and angiostatic functions in monocytes/macrophages and in mice with inflammatory corneal angiogenesis, whereas TLR2 inhibition attenuated these functions. Single-cell RNA sequencing revealed AKR1C1, a gene encoding aldo-keto reductase family 1 member C1, as the most significantly inducible gene in MSCs upon TLR2 stimulation, though its stimulation did not affect cell compositions. AKR1C1 protected MSCs against ferroptosis, increased secretion of anti-inflammatory cytokines, and enhanced their ability to drive monocytes/macrophages towards immunoregulatory phenotypes, leading to the amelioration of inflammatory corneal neovascularization in mice. Conclusion: Our findings suggest that activation of TLR2-AKR1C1 signaling in MSCs serves as an important pathway for the survival and homeostatic activities of MSCs during injury.

Therapeutic Efficacy of Interferon-Gamma and Hypoxia-Primed Mesenchymal Stromal Cells and Their Extracellular Vesicles: Underlying Mechanisms and Potentials in Clinical Translation

Multipotent mesenchymal stromal cells (MSCs) hold promises for cell therapy and tissue engineering due to their self-renewal and differentiation abilities, along with immunomodulatory properties and trophic factor secretion. Extracellular vesicles (EVs) from MSCs offer similar therapeutic effects. However, MSCs are heterogeneous and lead to variable outcomes. In vitro priming enhances MSC performance, improving immunomodulation, angiogenesis, proliferation, and tissue regeneration. Various stimuli, such as cytokines, growth factors, and oxygen tension, can prime MSCs. Two classical priming methods, interferon-gamma (IFN-γ) and hypoxia, enhance MSC immunomodulation, although standardized protocols are lacking. This review discusses priming protocols, highlighting the most commonly used concentrations and durations, along with mechanisms and in vivo therapeutics effects of primed MSCs and their EVs. The feasibility of up-scaling their production was also discussed. The review concluded that priming with IFN-γ or hypoxia (alone or in combination with other factors) boosted the immunomodulation capability of MSCs and their EVs, primarily via the JAK/STAT and PI3K/AKT and Leptin/JAK/STAT and TGF-β/Smad signalling pathways, respectively. Incorporating priming in MSC and EV production enables translation into cell-based or cell-free therapies for various disorders.

Anti-Inflammatory Effect of Dental Pulpa Mesenchymal Stem Cell Exosomes Loaded Mucoadhesive Hydrogel on Mice with Dental Nickel Hypersensitivity

In this study, the anti-inflammatory effect of dental pulp mesenchymal stem cell (MSCs) exosomes loaded to mucoadhesive hydrogel is investigated in a dental nickel hypersensitivity murine model. After culture of dental pulp MSCs in the third passage MSCs are loaded to a mucoadhesive hydrogel based on chitosan, cross-linked with genipin and modified with catechol groups. A dental nickel hypersensitivity model is created by administering NiCl2 and 10 µg mL-1 lipopolysaccharide to 4-6 week-old Balb-c mice by intradermal injection. In mice treated with dental pulp MSC exosomes and exosomes in hydrogel, interferron gamma (IFN-γ) secreting CD4+T lymphocyte ratios significantly increase compared to the untreated group (p < 0.05). IFN-γ and interleukin 10 (IL-10) expression in buccal mucosa tissue sections and IFN-γ secreting CD4+T lymphocyte ratios are found to be significantly higher in mice treated with dental pulpa MSCs (DPMSCs) exosomes and DPMSCs exosomes in hydrogel compared to the untreated group (p < 0.05). According to flow cytometry results, IL-4 secreting CD4+T lymphocytes are found to be significantly decreased in DPMSCs exosomes group compared to dental nickel hypersensitivity group (p < 0.05). Administration of DPMSCs exosomes with mucoadhesive hydrogel may be an alternative to current medication in the treatment of dental nickel hypersensitivity.

The role of toll-like receptors in orchestrating osteogenic differentiation of mesenchymal stromal cells and osteoimmunology

Osteoimmunology is a concept involving molecular and cellular crosstalk between the skeletal and immune systems. Toll-like receptors (TLRs) are widely expressed both on mesenchymal stromal cells (MSCs), the hematopoietic cells, and immune cells in the osteogenic microenvironment for bone development or repair. TLRs can sense both exogenous pathogen-associated molecular patterns (PAMPs) derived from microorganisms, and damage-associated molecular patterns (DAMPs) derived from normal cells subjected to injury, inflammation, or cell apoptosis under physiological or pathological conditions. Emerging studies reported that TLR signaling plays an important role in bone remodeling by directly impacting MSC osteogenic differentiation or osteoimmunology. However, how to regulate TLR signaling is critical and remains to be elucidated to promote the osteogenic differentiation of MSCs and new bone formation for bone tissue repair. This review outlines distinct TLR variants on MSCs from various tissues, detailing the impact of TLR pathway activation or inhibition on MSC osteogenic differentiation. It also elucidates TLR pathways' interplay with osteoclasts, immune cells, and extracellular vesicles (EVs) derived from MSCs. Furthermore, we explore biomaterial-based activation to guide MSCs' osteogenic differentiation. Therefore, understanding TLRs' role in this context has significant implications for advancing bone regeneration and repair strategies.

Exosome from IFN-γ-Primed Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Improved Skin Inflammation and Barrier Function

The pathogenesis of atopic dermatitis (AD) is multifactorial, including immune dysregulation and epidermal barrier defects, and a novel therapeutic modality that can simultaneously target multiple pathways is needed. We investigated the therapeutic effects of exosomes (IFN-γ-iExo) secreted from IFN-γ-primed induced pluripotent stem cell-derived mesenchymal stem cells (iMSC) in mice with Aspergillus fumigatus-induced AD. IFN-γ-iExo was epicutaneously administered to mice with AD-like skin lesions. The effects of IFN-γ-iExo treatment were investigated through clinical scores, transepidermal water loss (TEWL) measurements, and histopathology. To elucidate the therapeutic mechanism, we used an in vitro model of human keratinocyte HaCaT cells stimulated with IL-4 and IL-13 and performed extensive bioinformatics analysis of skin mRNA from mice. The expression of indoleamine 2,3-dioxygenase was higher in IFN-γ primed iMSCs than in iMSCs. In human keratinocyte HaCaT cells, treatment with IFN-γ-iExo led to decreases in the mRNA expression of thymic stromal lymphopoietin, IL-25, and IL-33 and increases in keratin 1, keratin 10, desmoglein 1, and ceramide synthase 3. IFN-γ-iExo treatment significantly improved clinical and histological outcomes in AD mice, including clinical scores, TEWL, inflammatory cell infiltration, and epidermal thickness. Bioinformatics analysis of skin mRNA from AD mice showed that IFN-γ-iExo treatment is predominantly involved in skin barrier function and T cell immune response. Treatment with IFN-γ-iExo improved the clinical and histological outcomes of AD mice, which were likely mediated by restoring proper skin barrier function and suppressing T cell-mediated immune response.

The critical role of apoptosis in mesenchymal stromal cell therapeutics and implications in homeostasis and normal tissue repair

Mesenchymal stromal cells (MSCs) have been extensively tested for the treatment of numerous clinical conditions and have demonstrated good safety but mixed efficacy. Although this outcome can be attributed in part to the heterogeneity of cell preparations, the lack of mechanistic understanding and tools to establish cell pharmacokinetics and pharmacodynamics, as well as the poorly defined criteria for patient stratification, have hampered the design of informative clinical trials. We and others have demonstrated that MSCs can rapidly undergo apoptosis after their infusion. Apoptotic MSCs are phagocytosed by monocytes/macrophages that are then reprogrammed to become anti-inflammatory cells. MSC apoptosis occurs when the cells are injected into patients who harbor activated cytotoxic T or NK cells. Therefore, the activation state of cytotoxic T or NK cells can be used as a biomarker to predict clinical responses to MSC treatment. Building on a large body of preexisting data, an alternative view on the mechanism of MSCs is that an inflammation-dependent MSC secretome is largely responsible for their immunomodulatory activity. We will discuss how these different mechanisms can coexist and are instructed by two different types of MSC "licensing": one that is cell-contact dependent and the second that is mediated by inflammatory cytokines. The varied and complex mechanisms by which MSCs can orchestrate inflammatory responses and how this function is specifically driven by inflammation support a physiological role for tissue stroma in tissue homeostasis, and it acts as a sensor of damage and initiator of tissue repair by reprogramming the inflammatory environment.

Therapeutic effects of mesenchymal stem cells and their derivatives in common skin inflammatory diseases: Atopic dermatitis and psoriasis

Chronic skin inflammatory diseases including atopic dermatitis (AD) and psoriasis have been considered uncontrolled inflammatory responses, which have usually troubled patients around the world. Moreover, the recent method to treat AD and psoriasis has been based on the inhibition, not regulation, of the abnormal inflammatory response, which can induce a number of side effects and drug resistance in long-term treatment. Mesenchymal stem/stromal cells (MSCs) and their derivatives have been widely used in immune diseases based on their regeneration, differentiation, and immunomodulation with few adverse effects, which makes MSCs a promising treatment for chronic skin inflammatory diseases. As a result, in this review, we aim to systematically discuss the therapeutic effects of various resources of MSCs, the application of preconditioning MSCs and engineering extracellular vesicles (EVs) in AD and psoriasis, and the clinical evaluation of the administration of MSCs and their derivatives, which can provide a comprehensive vision for the application of MSCs and their derivatives in future research and clinical treatment.

Preclinical Evaluation of interferon-gamma primed human Wharton's jelly-derived mesenchymal stem cells

The potential of human mesenchymal stem cells (MSCs) for cell therapy has been investigated in numerous immune-mediated conditions; MSCs are considered one of the most promising cellular therapeutics to treat intractable diseases. Recently, approaches to prime MSCs have been investigated, thereby generating cellular products with enhanced potential for a variety of clinical applications. Interferon-gamma (IFN-γ) priming is a current approach used to increase the therapeutic efficacy of MSCs. In this study, we determined the systemic toxicity, tumorigenicity and biodistribution of IFN-γ-primed Wharton's jelly-derived (WJ)-MSCs in male and female BALB/c-nu/nu mice. There were no deaths or pathologic lesions in the mice treated with 5 × 10⁶ cells/kg IFN-γ-primed MSCs in the repeated dose study. In the tumorigenicity study, one of the subcutaneously treated mice showed bronchioloalveolar adenoma in the lung but tested negative for human-specific anti-mitochondrial antibody, suggesting the spontaneous murine origin of the adenoma. A biodistribution study using real-time quantitative polymerase chain reaction demonstrated the systemic IFN-γ-primed MSC clearance by day 28. Based on the toxicity, biodistribution, and tumorigenicity studies, we concluded that IFN-γ-primed MSCs at 5 × 10⁶ cells/kg do not induce tumor formation and adverse changes.

Extracellular vesicles from IFN-γ-primed mesenchymal stem cells repress atopic dermatitis in mice

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by immune dysregulation, pruritus, and abnormal epidermal barrier function. Compared with conventional mesenchymal stem cell (MSC), induced pluripotent stem cell (iPSC)-derived mesenchymal stem cell (iMSC) is recognized as a unique source for producing extracellular vesicles (EVs) because it can be obtained in a scalable manner with an enhanced homogeneity. Stimulation of iMSCs with inflammatory cytokines can improve the immune-regulatory, anti-inflammatory, and tissue-repairing potential of iMSC-derived EVs.

RESULTS

Proteome analysis showed that IFN-γ-iMSC-EVs are enriched with protein sets that are involved in regulating interferon responses and inflammatory pathways. In AD mice, expression of interleukin receptors for Th2 cytokines (IL-4Rα/13Rα1/31Rα) and activation of their corresponding intracellular signaling molecules was reduced. IFN-γ-iMSC-EVs decreased itching, which was supported by reduced inflammatory cell infiltration and mast cells in AD mouse skin; reduced IgE receptor expression and thymic stromal lymphopoietin and NF-kB activation; and recovered impaired skin barrier, as evidenced by upregulation of key genes of epidermal differentiation and lipid synthesis.

CONCLUSIONS

IFN-γ-iMSC-EVs inhibit Th2-induced immune responses, suppress inflammation, and facilitate skin barrier restoration, contributing to AD improvement.

Therapeutic potential of adipose tissue-derivatives in modern dermatology

Stem cell-mediated therapies in combination with biomaterial and growth factor-based approaches in regenerative medicine are rapidly evolving with increasing application beyond the dermatologic field. Adipose-derived stem cells (ADSCs) are the more frequently used adult stem cells due to their abundance and easy access. In the case of volumetric defects, adipose tissue can take the shape of defects, restoring the volume and enhancing the regeneration of receiving tissue. When regenerative purposes prevail on volume restoration, the stromal vascular fraction (SVF) rich in staminal cells, purified mesenchymal stem cells (MSCs) or their cell-free derivatives grafting are favoured. The therapeutic efficacy of acellular approaches is explained by the fact that a significant part of the natural propensity of stem cells to repair damaged tissue is ascribable to their secretory activity that combines mitogenic factors, cytokines, chemokines and extracellular matrix components. Therefore, the secretome's ability to modulate multiple targets simultaneously demonstrated preclinical and clinical efficacy in reversing pathological mechanisms of complex conditions such atopic dermatitis (AD), vitiligo, psoriasis, acne and Lichen sclerosus (LS), non-resolving wounds and alopecia. This review analysing both in vivo and in vitro models gives an overview of the clinical relevance of adipose tissue-derivatives such as autologous fat graft, stromal vascular fraction, purified stem cells and secretome for skin disorders application. Finally, we highlighted the major disease-specific limitations and the future perspective in this field.

Umbilical cord mesenchymal stromal cells-from bench to bedside

In recent years, mesenchymal stromal cells (MSCs) have generated a lot of attention due to their paracrine and immuno-modulatory properties. mesenchymal stromal cells derived from the umbilical cord (UC) are becoming increasingly recognized as having increased therapeutic potential when compared to mesenchymal stromal cells from other sources. The purpose of this review is to provide an overview of the various compartments of umbilical cord tissue from which mesenchymal stromal cells can be isolated, the differences and similarities with respect to their regenerative and immuno-modulatory properties, as well as the single cell transcriptomic profiles of in vitro expanded and freshly isolated umbilical cord-mesenchymal stromal cells. In addition, we discuss the therapeutic potential and biodistribution of umbilical cord-mesenchymal stromal cells following systemic administration while providing an overview of pre-clinical and clinical trials involving umbilical cord-mesenchymal stromal cells and their associated secretome and extracellular vesicles (EVs). The clinical applications of umbilical cord-mesenchymal stromal cells are also discussed, especially in relation to obstacles and potential solutions for their effective translation from bench to bedside.

Recent advances to enhance the immunomodulatory potential of mesenchymal stem cells

Considering the unique therapeutic potential of mesenchymal stem cells (MSCs), including their immunosuppressive and immunomodulatory properties as well as their ability to improve tissue regeneration, these cells have attracted the attention of scientists and clinicians for the treatment of different inflammatory and immune system mediated disorders. However, various clinical trials using MSCs for the therapeutic purpose are conflicting and differ from the results of promising preclinical studies. This inconsistency is caused by several factors such as poor migration and homing capacities, low survival rate, low level of proliferation and differentiation, and donor-dependent variation of the cells. Enhancement and retention of persistent therapeutic effects of the cells remain a challenge to overcome in MSC-based therapy. In this review, we summarized various approaches to enhance the clinical outcomes of MSC-based therapy as well as revised current and future perspectives for the creation of cellular products with improved potential for diverse clinical applications.

Study of immunomodulatory effects of mesenchymal stem cell-derived exosomes in mouse model of LPS induced systemic inflammation

BACKGROUND

Sepsis is a debilitating systemic inflammation that resulted from infection or injury. Despite many advances in treatment, the resulting mortality rate has remained high due to increasing antibiotic resistance and aging communities. The present study investigated the effects of stem cell-derived exosomes in a mouse model of LPS-induced systemic inflammation.

MATERIALS AND METHODS

To induce sepsis, the LPS model was used. Mice were divided into three groups: normal, patient group (LPS + PBS), and treatment group (LPS + exosome). The treatment group received an intravenous exosome 1 h after induction of the model. Patient and treatment groups were sacrificed at 4, 6, 24, and 48 h after induction of the model, and their tissues were isolated. Blood samples were taken from animal hearts to perform biochemical and immunological tests. The study results were analyzed using Graph Pad Prism software version 9.

RESULTS

Mesenchymal stem cell-derived exosomes decreased serum levels of ALT and AST liver enzymes, decreased neutrophil to lymphocyte ratio (NLR), and improved kidney, liver, and lung tissue damage at 4, 6, and 24 h after model induction. At 24 h, the exosomes were able to reduce serum urea levels. This study revealed decreased levels of inflammatory cytokines such as IL-6, IL-1β, and TNF-α after exosome injection.

CONCLUSION

Our findings suggest that treating mice with stem cell-derived exosomes can ameliorate the destructive effects of inflammation caused by sepsis by reducing inflammatory factors and tissue damage.

Dental Pulp-Derived Stem Cells Reduce Inflammation, Accelerate Wound Healing and Mediate M2 Polarization of Myeloid Cells

This work aimed to validate the potential use of dental pulp-derived stem cells (DPSCs) for the treatment of inflammation by defining their mechanisms of action. We planned to investigate whether priming of DPSC with proinflammatory molecules had any impact on their behavior and function. In the first step of our validation in vitro, we showed that priming of DPSCs with the bioactive agents LPS, TNF-α, or IFN-γ altered DPSCs’ immunologic properties by increasing their expression levels of IL-10, HGF, IDO, and IL-4 and by decreasing their mitochondrial functions. Moreover, DPSCs induced accelerated wound healing irrespective of priming, as determined by using a gut epithelial cell line in a scratch wound assay. Wound healing of gut epithelial cells was mediated by regulating the expressions of AKT, NF-κB, and ERK1/2 proteins compared to the control epithelial cells. In addition, primed DPSCs altered monocyte polarization toward an immuno-suppressive phenotype (M2), where monocytes expressed higher levels of IL-4R, IL-6, Arg1, and YM-1 compared to monocytes cultured with control DPSCs. In silico analysis revealed that this was accomplished in part by the interaction between kynurenine and PPARγ, which regulated the expression of M2 differentiation-related genes. Collectively, these data provided evidence that the DPSCs reduced inflammation, induced M2 polarization of myeloid cells, and healed damaged gut epithelial cells through inactivation of inflammation and modulating constitutively active signaling pathways.

The Inflammatory Lung Microenvironment; a Key Mediator in MSC Licensing

Recent clinical trials of mesenchymal stromal cell (MSC) therapy for various inflammatory conditions have highlighted the significant benefit to patients who respond to MSC administration. Thus, there is strong interest in investigating MSC therapy in acute inflammatory lung conditions, such as acute respiratory distress syndrome (ARDS). Unfortunately, not all patients respond, and evidence now suggests that the differential disease microenvironment present across patients and sub-phenotypes of disease or across disease severities influences MSC licensing, function and therapeutic efficacy. Here, we discuss the importance of licensing MSCs and the need to better understand how the disease microenvironment influences MSC activation and therapeutic actions, in addition to the need for a patient-stratification approach.

Mesenchymal stem/stromal cell therapy in atopic dermatitis and chronic urticaria: immunological and clinical viewpoints

Allergic diseases are immune-mediated diseases. Allergies share a common immunopathogenesis, with specific differences according to the specific disease. Mesenchymal stem/stromal cells (MSCs) have been applied to people suffering from allergic and many other diseases. In this review, the immunologic roles of MSCs are systemically reviewed according to disease immunopathogenesis from a clinical viewpoint. MSCs seem to be a promising therapeutic modality not only as symptomatic treatments but also as causative and even preventive treatments for allergic diseases, including atopic dermatitis and chronic urticaria.

Overexpression of Hepatocyte Growth Factor in Dental Pulp Stem Cells Ameliorates the Severity of Psoriasis by Reducing Inflammatory Responses

Psoriasis is an autoimmune disease still lacking standard treatment, and it has been demonstrated that mesenchymal stem cells (MSCs) are capable of immunoregulation. The underlying mechanism might involve the secretion of soluble cytokines, such as hepatocyte growth factor (HGF). This study aims to investigate the therapeutic effect of HGF-overexpressed dental pulp stem cells (DPSCs) [DPSCs; HGF overexpressed DPSCs (HGF-DPSCs)] on imiquimod-induced psoriasis. DPSCs were isolated and transfected by adenovirus vector carrying HGF gene (Ad-HGF). The immunoregulatry abilities of DPSCs and HGF-DPSCs were investigated by coculture of the MSCs with peripheral blood mononuclear cells (PBMCs) under appropriated stimulation. The psoriatic mice were treated with saline control, DPSCs, or HGF-DPSCs. Then the mice spleens were collected and weighted. The psoriatic skin lesions were analyzed by Hematoxylin/Eosin and immunohistochemical staining for histopathological changes, and quantitative real-time polymerase chain reaction to detect the expression levels of CD4⁺ T cell-related transcription factors and cytokines. The mice blood serum was measured by MILLIPLEX analysis and enzyme-linked immunosorbent assay to evaluate the expression levels of inflammation cytokines. The coculture experiments showed HGF overexpression enhanced the immunoregulation abilities of DPSCs not by suppressing PBMCs' proliferation, but by downregulating T helper 1 (Th1), Th17 cells, and upregulating regulatory T (Treg) cells. In psoriatic skin lesions, the psoriasis-like erythema, scaling, and thickening were ameliorated; and the expression of cytokeratin 6 (CK6), and cytokeratin 17 (CK17) were downregulated by DPSCs and HGF-DPSCs treatment. HGF overexpression enhanced the decrease of spleen masses; enhanced the downregulation of the expression levels of interferon-gamma (IFN-γ), tumor necrosis factor-α, and interleukin (IL)-17A in the blood serums; enhanced the downregulation of T-box transcription factor 21 (T-bet), IFN-γ, retinoic acid-related orphan receptor-γt (RORγt), IL-17A, IL-17F, IL-23, and upregulation of Foxp3 and IL-10 in the psoriatic skin lesions. Therefore, HGF overexpression enhanced DPSCs' treatment effect on psoriasis mainly by reducing inflammatory responses. These findings might provide new immunoregulation strategies for psoriasis treatment.

Current Advanced Therapies Based on Human Mesenchymal Stem Cells for Skin Diseases

Skin disease may be related with immunological disorders, external aggressions, or genetic conditions. Injuries or cutaneous diseases such as wounds, burns, psoriasis, and scleroderma among others are common pathologies in dermatology, and in some cases, conventional treatments are ineffective. In recent years, advanced therapies using human mesenchymal stem cells (hMSCs) from different sources has emerged as a promising strategy for the treatment of many pathologies. Due to their properties; regenerative, immunomodulatory and differentiation capacities, they could be applied for the treatment of cutaneous diseases. In this review, a total of thirteen types of hMSCs used as advanced therapy have been analyzed, considering the last 5 years (2015-2020). The most investigated types were those isolated from umbilical cord blood (hUCB-MSCs), adipose tissue (hAT-MSCs) and bone marrow (hBM-MSCs). The most studied diseases were wounds and ulcers, burns and psoriasis. At preclinical level, in vivo studies with mice and rats were the main animal models used, and a wide range of types of hMSCs were used. Clinical studies analyzed revealed that cell therapy by intravenous administration was the advanced therapy preferred except in the case of wounds and burns where tissue engineering was also reported. Although in most of the clinical trials reviewed results have not been posted yet, safety was high and only local slight adverse events (mild nausea or abdominal pain) were reported. In terms of effectiveness, it was difficult to compare the results due to the different doses administered and variables measured, but in general, percentage of wound's size reduction was higher than 80% in wounds, Psoriasis Area and Severity Index and Severity Scoring for Atopic Dermatitis were significantly reduced, for scleroderma, parameters such as Modified Rodnan skin score (MRSC) or European Scleroderma Study Group activity index reported an improvement of the disease and for hypertrophic scars, Vancouver Scar Scale (VSS) score was decreased after applying these therapies. On balance, hMSCs used for the treatment of cutaneous diseases is a promising strategy, however, the different experimental designs and endpoints stablished in each study, makes necessary more research to find the best way to treat each patient and disease.

Exosomes From Adipose-Derived Stem Cells: The Emerging Roles and Applications in Tissue Regeneration of Plastic and Cosmetic Surgery

Adipose-derived stem cells (ASCs) are an important stem cell type separated from adipose tissue, with the properties of multilineage differentiation, easy availability, high proliferation potential, and self-renewal. Exosomes are novel frontiers of intercellular communication regulating the biological behaviors of cells, such as angiogenesis, immune modulation, proliferation, and migration. ASC-derived exosomes (ASC-exos) are important components released by ASCs paracrine, possessing multiple biological activities. Tissue regeneration requires coordinated “vital networks” of multiple growth factors, proteases, progenitors, and immune cells producing inflammatory cytokines. Recently, as cell-to-cell messengers, ASC-exos have received much attention for the fact that they are important paracrine mediators contributing to their suitability for tissue regeneration. ASC-exos, with distinct properties by encapsulating various types of bioactive cargoes, are endowed with great application potential in tissue regeneration, mechanically via the migration and proliferation of repair cells, facilitation of the neovascularization, and other specific functions in different tissues. Here, this article elucidated the research progress of ASC-exos about tissue regeneration in plastic and cosmetic surgery, including skin anti-aging therapy, dermatitis improvement, wound healing, scar removal, flap transplantation, bone tissue repair and regeneration, obesity prevention, fat grafting, breast cancer, and breast reconstruction. Deciphering the biological properties of ASC-exos will provide further insights for exploring novel therapeutic strategies of tissue regeneration in plastic and cosmetic surgery.

Regenerative potential of Wharton's jelly-derived mesenchymal stem cells: A new horizon of stem cell therapy

Umbilical cord Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) have recently gained considerable attention in the field of regenerative medicine. Their high proliferation rate, differentiation ability into various cell lineages, easy collection procedure, immuno-privileged status, nontumorigenic properties along with minor ethical issues make them an ideal approach for tissue repair. Besides, the number of WJ-MSCs in the umbilical cord samples is high as compared to other sources. Because of these properties, WJ-MSCs have rapidly advanced into clinical trials for the treatment of a wide range of disorders. Therefore, this paper summarized the current preclinical and clinical studies performed to investigate the regenerative potential of WJ-MSCs in neural, myocardial, skin, liver, kidney, cartilage, bone, muscle, and other tissue injuries.

Mesenchymal Stem Cells and Atopic Dermatitis: A Review

Mesenchymal stem/stromal cells (MSCs) are stromal-derived non-hematopoietic progenitor cells that reside in and can be expanded from various tissues sources of adult and neonatal origin, such as the bone marrow, umbilical cord, umbilical cord blood, adipose tissue, amniotic fluid, placenta, dental pulp and skin. The discovery of the immunosuppressing action of MSCs on T cells has opened new perspectives for their use as a therapeutic agent for immune-mediated disorders, including allergies. Atopic dermatitis (AD), a chronic and relapsing skin disorder that affects up to 20% of children and up to 3% of adults worldwide, is characterized by pruritic eczematous lesions, impaired cutaneous barrier function, Th2 type immune hyperactivation and, frequently, elevation of serum immunoglobulin E levels. Although, in the dermatology field, the application of MSCs as a therapeutic agent was initiated using the concept of cell replacement for skin defects and wound healing, accumulating evidence have shown that MSC-mediated immunomodulation can be applicable to the treatment of inflammatory/allergic skin disorders. Here we reviewed the pre-clinical and clinical studies and possible biological mechanisms of MSCs as a therapeutic tool for the treatment of atopic dermatitis.

Review-Current Concepts in Inflammatory Skin Diseases Evolved by Transcriptome Analysis: In-Depth Analysis of Atopic Dermatitis and Psoriasis

During the last decades, high-throughput assessment of gene expression in patient tissues using microarray technology or RNA-Seq took center stage in clinical research. Insights into the diversity and frequency of transcripts in healthy and diseased conditions provide valuable information on the cellular status in the respective tissues. Growing with the technique, the bioinformatic analysis toolkit reveals biologically relevant pathways which assist in understanding basic pathophysiological mechanisms. Conventional classification systems of inflammatory skin diseases rely on descriptive assessments by pathologists. In contrast to this, molecular profiling may uncover previously unknown disease classifying features. Thereby, treatments and prognostics of patients may be improved. Furthermore, disease models in basic research in comparison to the human disease can be directly validated. The aim of this article is not only to provide the reader with information on the opportunities of these techniques, but to outline potential pitfalls and technical limitations as well. Major published findings are briefly discussed to provide a broad overview on the current findings in transcriptomics in inflammatory skin diseases.