Skin mesenchymal stem cells: Prospects for clinical dermatology

Mesenchymal stem cells in autoimmune disease: A systematic review and meta-analysis of pre-clinical studies

Mesenchymal Stem Cells (MSCs) are of interest in the clinic because of their immunomodulation capabilities, capacity to act upstream of inflammation, and ability to sense metabolic environments. In standard physiologic conditions, they play a role in maintaining the homeostasis of tissues and organs; however, there is evidence that they can contribute to some autoimmune diseases. Gaining a deeper understanding of the factors that transition MSCs from their physiological function to a pathological role in their native environment, and elucidating mechanisms that reduce their therapeutic relevance in regenerative medicine, is essential. We conducted a Systematic Review and Meta-Analysis of human MSCs in preclinical studies of autoimmune disease, evaluating 60 studies that included 845 patient samples and 571 control samples. MSCs from any tissue source were included, and the study was limited to four autoimmune diseases: multiple sclerosis, rheumatoid arthritis, systemic sclerosis, and lupus. We developed a novel Risk of Bias tool to determine study quality for in vitro studies. Using the International Society for Cell & Gene Therapy's criteria to define an MSC, most studies reported no difference in morphology, adhesion, cell surface markers, or differentiation into bone, fat, or cartilage when comparing control and autoimmune MSCs. However, there were reported differences in proliferation. Additionally, 308 biomolecules were differentially expressed, and the abilities to migrate, invade, and form capillaries were decreased. The findings from this study could help to explain the pathogenic mechanisms of autoimmune disease and potentially lead to improved MSC-based therapeutic applications.

Advanced function, design and application of skin substitutes for skin regeneration

The development of skin substitutes aims to replace, mimic, or improve the functions of human skin, regenerate damaged skin tissue, and replace or enhance skin function. This includes artificial skin, scaffolds or devices designed for treatment, imitation, or improvement of skin function in wounds and injuries. Therefore, tremendous efforts have been made to develop functional skin substitutes. However, there is still few reports systematically discuss the relationship between the advanced function and design requirements. In this paper, we review the classification, functions, and design requirements of artificial skin or skin substitutes. Different manufacturing strategies for skin substitutes such as hydrogels, 3D/4D printing, electrospinning, microfluidics are summarized. This review also introduces currently available skin substitutes in clinical trials and on the market and the related regulatory requirements. Finally, the prospects and challenges of skin substitutes in the field of tissue engineering are discussed.

The efficacy and safety of low- versus high-fluence fractional picosecond Nd:YAG 1064-nm laser in the treatment of acne scars: A randomized split-face comparison study

BACKGROUND

Differences in clinical efficacy based on the fluence of fractional picosecond laser treatment for acne scars are unknown.

OBJECTIVE

To compare the efficacy and safety of low-fluence versus high-fluence fractional picosecond Nd:YAG 1064-nm laser treatment in acne scar patients.

METHODS

In this 12-week, investigator-blinded, randomized, split-face study, 25 patients with moderate-to-severe acne scars received three sessions of high-fluence laser treatment (1.0 J/cm2 ) on one side of their face and low-fluence (0.3 J/cm2 ) on the other side every 4 weeks. Patients were assessed using acne scar counts, the scar global assessment (SGA), and the ECCA scar grading scale every 4 weeks. The histological analysis compared the acne scars obtained before and 4 weeks after treatment.

RESULTS

At their last visit, 88.00% and 92.00% of the subjects achieved >30% reduction in scar counts on the low- and high-fluence sides, respectively, without a significant difference between the two sides. On both sides, the scar counts, SGA, and ECCA score significantly improved 4 weeks after the last treatment. Although the high-fluence side showed a greater reduction in scar counts (-66.73%) than the low-fluence side (-62.13%), the two sides had no significant difference in the grading scores. The high-fluence side showed significantly more severe pain and higher side-effect scores immediately and 4 weeks after treatment. Histological analysis revealed a significantly increased collagen, elastin, and vimentin expression after treatment on the low-fluence side.

CONCLUSIONS

The low-fluence setting demonstrated comparable efficacy and superior safety in treating acne scars compared with the high-fluence setting.

Mesenchymal Stem Cells: Generalities and Clinical Significance in Feline and Canine Medicine

Mesenchymal stem cells (MSCs) are multipotent cells: they can proliferate like undifferentiated cells and have the ability to differentiate into different types of cells. A considerable amount of research focuses on the potential therapeutic benefits of MSCs, such as cell therapy or tissue regeneration, and MSCs are considered powerful tools in veterinary regenerative medicine. They are the leading type of adult stem cells in clinical trials owing to their immunosuppressive, immunomodulatory, and anti-inflammatory properties, as well as their low teratogenic risk compared with pluripotent stem cells. The present review details the current understanding of the fundamental biology of MSCs. We focus on MSCs' properties and their characteristics with the goal of providing an overview of therapeutic innovations based on MSCs in canines and felines.

Apoptotic Vesicles Regulate Bone Metabolism via the miR1324/SNX14/SMAD1/5 Signaling Axis

Mesenchymal stem cells (MSCs) are widely used in the treatment of diseases. After their in vivo application, MSCs undergo apoptosis and release apoptotic vesicles (apoVs). This study investigates the role of apoVs derived from human bone marrow mesenchymal stem cells (hBMMSCs) in bone metabolism and the molecular mechanism of the observed effects. The results show that apoVs can promote osteogenesis and inhibit osteoclast formation in vitro and in vivo. ApoVs may therefore attenuate the bone loss caused by primary and secondary osteoporosis and stimulate bone regeneration in areas of bone defect. The mechanisms responsible for apoV-induced bone regeneration include the release of miR1324, which inhibit expression of the target gene Sorting Nexin 14 (SNX14) and thus activate the SMAD1/5 pathway in target cells. Given that MSC-derived apoVs are easily obtained and stored, with low risks of immunological rejection and neoplastic transformation, The findings suggest a novel therapeutic strategy to treat bone loss, including via cell-free approaches to bone tissue engineering.

Ficoll density gradient sedimentation isolation of pelage hair follicle mesenchymal stem cells from adult mouse back skin: a novel method for hair follicle mesenchymal stem cells isolation

Background

Hair follicle mesenchymal stem cells (HF-MSCs) have great potential for cell therapy. Traditional method to isolate whisker HF-MSC is time-consuming and few in cell numbers. How to quickly and conveniently obtain a large number of HF-MSC for experimental research is a problem worth exploring.

Methods

Two-step Ficoll Density Gradient Sedimentation (FDGS) was performed to isolate pelage HF-MSC from adult mice. The characteristic of the isolated cells was identified and compared with whisker HF-MSC by immunofluorescence staining, flow cytometry, three-lineage differentiation and hair follicle reconstruction. Pelage HF-MSC and exosomes were injected into the dorsal skin of mice as well as hair follicle organ culture to explore its role in promoting hair growth. The cells and exosomes distribution were located by immunofluorescence staining.

Results

Isolated pelage HF-MSC expressed similar markers (ALP, Versican, NCAM, Nestin), showed similar growth pattern, possessed similar mesenchymal stem cells function and hair follicle induction ability as whisker HF-MSC. A large number of cells can be obtained with fewer mice compared to traditional method. Injected pelage HF-MSC promoted hair growth by secreting exosomes.

Conclusion

A large number of Pelage HF-MSC can be isolated by FDGS, which can promote hair growth by secreting exosomes which may target the dermal papilla and hair matrix region of host hair follicle.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03051-3.

Cell-based drug delivery systems and their in vivo fate

Cell-based drug delivery systems (DDSs) have received attention recently because of their unique biological properties and self-powered functions, such as excellent biocompatibility, low immunogenicity, long circulation time, tissue-homingcharacteristics, and ability to cross biological barriers. A variety of cells, including erythrocytes, stem cells, and lymphocytes, have been explored as functional vectors for the loading and delivery of various therapeutic payloads (e.g., small-molecule and nucleic acid drugs) for subsequent disease treatment. These cell-based DDSs have their own unique in vivo fates, which are attributed to various factors, including their biological properties and functions, the loaded drugs and loading process, physiological and pathological circumstances, and the body's response to these carrier cells, which result in differences in drug delivery efficiency and therapeutic effect. In this review, we summarize the main cell-based DDSs and their biological properties and functions, applications in drug delivery and disease treatment, and in vivo fate and influencing factors. We envision that the unique biological properties, combined with continuing research, will enable development of cell-based DDSs as friendly drug vectors for the safe, effective, and even personalized treatment of diseases.

MSCs and their exosomes: a rapidly evolving approach in the context of cutaneous wounds therapy

Currently, mesenchymal stem/stromal stem cell (MSC) therapy has become a promising option for accelerating cutaneous wound healing. In vivo reports have outlined the robust competences of MSCs to offer a solid milieu by inhibition of inflammatory reactions, which in turn, enables skin regeneration. Further, due to their great potential to stimulate angiogenesis and also facilitate matrix remodeling, MSCs hold substantial potential as future therapeutic strategies in this context. The MSCs-induced wound healing is thought to mainly rely on the secretion of a myriad of paracrine factors in addition to their direct differentiation to skin-resident cells. Besides, MSCs-derived exosomes as nanoscale and closed membrane vesicles have recently been suggested as an effective and cell-free approach to support skin regeneration, circumventing the concerns respecting direct application of MSCs. The MSCs-derived exosomes comprise molecular components including lipid, proteins, DNA, microRNA, and also mRNA, which target molecular pathways and also biological activities in recipient cells (e.g., endothelial cell, keratinocyte, and fibroblast). The secreted exosome modifies macrophage activation, stimulates angiogenesis, and instigates keratinocytes and dermal fibroblast proliferations as well as migrations concurrently regulate inherent potential of myofibroblast for adjustment of turnover of the ECM. In the present review, we will focus on the recent findings concerning the application of MSCs and their derivative exosome to support wound healing and skin regeneration, with special focus on last decade in vivo reports.

Keratinocyte-Like Cells Trans-Differentiated from Human Adipose-Derived Stem Cells, Facilitate Skin Wound Healing in Mice

Background

Mesenchymal stem cells (MSCs) have been reported to promote wound healing in both animal models and human studies. Among MSCs, adipose-derived stem cells (ADSCs) can be easily harvested in large quantities.

Objective

We investigated whether skin wound healing in mice can be facilitated by keratinocyte-like cells differentiated from ADSCs (KC-ADSCs).

Methods

For the wound contraction and epithelialization model, a 20 mm×20 mm fullthickness skin wound was made on the dorsum. For the wound epithelialization model, a 6 mm×6 mm full-thickness skin wound was made on the dorsum. A nitrile rubber stent with an inner diameter of 8 mm was sutured around the wounds to minimize wound contraction. Undifferentiated ADSCs (uADSCs) or KC-ADSCs was injected around the wound base in both models. To evaluate whether the injected ADSCs could enhance wound contraction in a skin wound, the contractile activity of ADSCs was assessed by an in vitro type I collagen gel contraction assay. Alpha-smooth muscle actin (αSMA) expressions in uADSCs and KC-ADSCs were also evaluated by flow cytometry and real-time polymerase chain reaction.

Results

In a wound contraction and epithelialization model, KC-ADSCs further facilitated wound healing compared with uADSCs. In a wound epithelialization model, KC-ADSCs also further facilitated wound epithelialization compared with uADSCs. The contractile activity of KC-ADSCs was lower than that of uADSCs. The uADSCs expressed high levels of αSMA, which decreased after the differentiation into keratinocyte-like cells.

Conclusion

Our results suggest that the wound healing effect of KC-ADSCs depends primarily on re-epithelialization rather than wound contraction.

Biodistribution of Mesenchymal Stromal Cells after Administration in Animal Models and Humans: A Systematic Review

Mesenchymal Stromal Cells (MSCs) are of great interest in cellular therapy. Different routes of administration of MSCs have been described both in pre-clinical and clinical reports. Knowledge about the fate of the administered cells is critical for developing MSC-based therapies. The aim of this review is to describe how MSCs are distributed after injection, using different administration routes in animal models and humans. A literature search was performed in order to consider how MSCs distribute after intravenous, intraarterial, intramuscular, intraarticular and intralesional injection into both animal models and humans. Studies addressing the biodistribution of MSCs in “in vivo” animal models and humans were included. After the search, 109 articles were included in the review. Intravenous administration of MSCs is widely used; it leads to an initial accumulation of cells in the lungs with later redistribution to the liver, spleen and kidneys. Intraarterial infusion bypasses the lungs, so MSCs distribute widely throughout the rest of the body. Intramuscular, intraarticular and intradermal administration lack systemic biodistribution. Injection into various specific organs is also described. Biodistribution of MSCs in animal models and humans appears to be similar and depends on the route of administration. More studies with standardized protocols of MSC administration could be useful in order to make results homogeneous and more comparable.

Cellular human tissue-engineered skin substitutes investigated for deep and difficult to heal injuries

Wound healing is an important function of skin; however, after significant skin injury (burns) or in certain dermatological pathologies (chronic wounds), this important process can be deregulated or lost, resulting in severe complications. To avoid these, studies have focused on developing tissue-engineered skin substitutes (TESSs), which attempt to replace and regenerate the damaged skin. Autologous cultured epithelial substitutes (CESs) constituted of keratinocytes, allogeneic cultured dermal substitutes (CDSs) composed of biomaterials and fibroblasts and autologous composite skin substitutes (CSSs) comprised of biomaterials, keratinocytes and fibroblasts, have been the most studied clinical TESSs, reporting positive results for different pathological conditions. However, researchers' purpose is to develop TESSs that resemble in a better way the human skin and its wound healing process. For this reason, they have also evaluated at preclinical level the incorporation of other human cell types such as melanocytes, Merkel and Langerhans cells, skin stem cells (SSCs), induced pluripotent stem cells (iPSCs) or mesenchymal stem cells (MSCs). Among these, MSCs have been also reported in clinical studies with hopeful results. Future perspectives in the field of human-TESSs are focused on improving in vivo animal models, incorporating immune cells, designing specific niches inside the biomaterials to increase stem cell potential and developing three-dimensional bioprinting strategies, with the final purpose of increasing patient's health care. In this review we summarize the use of different human cell populations for preclinical and clinical TESSs under research, remarking their strengths and limitations and discuss the future perspectives, which could be useful for wound healing purposes.

Advanced Medical Therapies in the Management of Non-Scarring Alopecia: Areata and Androgenic Alopecia

Alopecia is a challenging condition for both physicians and patients. Several topical, intralesional, oral, and surgical treatments have been developed in recent decades, but some of those therapies only provide partial improvement. Advanced medical therapies are medical products based on genes, cells, and/or tissue engineering products that have properties in regenerating, repairing, or replacing human tissue. In recent years, numerous applications have been described for advanced medical therapies. With this background, those therapies may have a role in the treatment of various types of alopecia such as alopecia areata and androgenic alopecia. The aim of this review is to provide dermatologists an overview of the different advanced medical therapies that have been applied in the treatment of alopecia, by reviewing clinical and basic research studies as well as ongoing clinical trials.

Hair Follicle as a Source of Pigment-Producing Cells for Treatment of Vitiligo: An Alternative to Epidermis?

To discuss the advantages and limitations of hair follicle-derived cell transplantation (FCT) in vitiligo, compared to the epidermal cell transplantation (ECT), and the knowledge gap which is required to be bridged. The papers relevant to the purpose was reviewed. Surgical approaches for treating vitiligo are based on the idea of replenishing lost melanocytes. Skin and hair follicles as the main sources of melanocytes have been applied for this purpose transferring the whole tissue or tissue-derived cell suspension to the vitiligo lesions. Considering the differences between hair follicle and epidermis in terms of the constituting cell populations, phenotype and function of melanocytes, and micro-environmental factors, different response of vitiligo patients to treatment with FCT or ECT would be expected theoretically. However, there is currently a lack of evidence on such a difference. However, ECT appears to be a more feasible, less time-consuming, and more comfortable treatment for both physicians and patients. Although the current evidence has not shown a significant difference between ECT and FCT in terms of efficacy, ECT appears to be more feasible specifically in the treatment of large lesions. However, further randomized controlled clinical trials with larger sample sizes and longer follow-up durations are required to be conducted to draw a definite conclusion on comparing FCT with ECT in terms of the safety, efficacy, durability of the therapeutic effects, and indications in vitiligo patients.

The Clinical Trials of Mesenchymal Stem Cell Therapy in Skin Diseases: An Update and Concise Review

The skin is one of the crucial body organs with anatomy and physiology linked to various disorders including congenital and acquired diseases. Nowadays, mesenchymal stem cell (MSCs)- based therapy has appeared as a promising therapeutic field, in which many see opportunities to cure the costliest and incurable diseases. However, one question to be asked is that if the use of MSCs in clinical trials studies and diseases treatment has improved. In this study, the clinical trials using MSCs in skin diseases were reviewed. A remarkable number of clinical trial studies are in progress in this field; however, only a few of them have led to tangible benefits for patients. The relevant papers and ongoing clinical trials that address MSC's therapeutic goals for various skin disorders were examined. This review can be very useful for both the dermatologists and basic skin researchers interested in contributing to stem cell-based therapeutic researches in the area of skin disorders.

The Long Pentraxin PTX3 as a Link Between Innate Immunity, Tissue Remodeling, and Cancer

The innate immune system comprises a cellular and a humoral arm. Humoral pattern recognition molecules include complement components, collectins, ficolins, and pentraxins. These molecules are involved in innate immune responses by recognizing microbial moieties and damaged tissues, activating complement, exerting opsonic activity and facilitating phagocytosis, and regulating inflammation. The long pentraxin PTX3 is a prototypic humoral pattern recognition molecule that, in addition to providing defense against infectious agents, plays several functions in tissue repair and regulation of cancer-related inflammation. Characterization of the PTX3 molecular structure and biochemical properties, and insights into its interactome and multiple roles in tissue damage and remodeling support the view that microbial and matrix recognition are evolutionarily conserved functions of humoral innate immunity molecules.

Impact of HOXB7 overexpression on human adipose-derived mesenchymal progenitors

Background

The ex vivo expansion potential of mesenchymal stromal/stem cells (MSC) together with their differentiation and secretion properties makes these cells an attractive tool for transplantation and tissue engineering. Although the use of MSC is currently being tested in a growing number of clinical trials, it is still desirable to identify molecular markers that may help improve their performance both in vitro and after transplantation.

Methods

Recently, HOXB7 was identified as a master player driving the proliferation and differentiation of bone marrow mesenchymal progenitors. In this study, we investigated the effect of HOXB7 overexpression on the ex vivo features of adipose mesenchymal progenitors (AD-MSC).

Results

HOXB7 increased AD-MSC proliferation potential, reduced senescence, and improved chondrogenesis together with a significant increase of basic fibroblast growth factor (bFGF) secretion.

Conclusion

While further investigations and in vivo models shall be applied for better understanding, these data suggest that modulation of HOXB7 may be a strategy for innovative tissue regeneration applications.

Isolation and biological characterization of mesenchymal stem cells from goose dermis

The skin is a natural target of stem cell research because of its large size and easy accessibility. Cutaneous mesenchymal stem cells have shown to be a promising source of various adult stem cell or progenitor cell populations, which provide an important source of stem cell-based investigation. Nowadays, much work has been done on dermal-derived mesenchymal stem cells (DMSCs) from humans, mice, sheep, and other mammals, but the literature on avian species has been rarely reported. As an animal model, the goose is an endemic species abounding in dermal tissues which is important in the global economy. In this study, we isolated and established the mesenchymal stem cell line from dermis tissue of goose, which were subcultured to passage 21 in vitro without loss of their functional integrity in terms of morphology, renewal capacity, and presence of mesenchymal stem cell markers. Cryopreservation and resuscitation were also observed in different passages. To investigate the biological characteristics of goose DMSCs, immunofluorescence, reverse transcription-polymerase chain reaction, and flow cytometry were used to detect the characteristic surface markers. Growth curves and the capacity of colony forming were performed to test the self-renew and proliferative ability. Furthermore, the DMSCs are induced to osteoblasts, adipocytes, and chondrocytes in vitro. Our results suggest that DMSCs isolated from goose embryos possess similar biological characteristics to those from other species. The methods in establishment and cultivation of goose DMSCs line demonstrated a good self-renew and expansion potential in vitro, which provided a technological platform for preserving the valuable genetic resources of poultry and a great inspiration for in vitro investigation of avian MSCs.

3D bioprinter applied picosecond pulsed electric fields for targeted manipulation of proliferation and lineage specific gene expression in neural stem cells

OBJECTIVE

Picosecond pulse electric fields (psPEF) have the potential to elicit functional changes in mammalian cells in a non-contact manner. Such electro-manipulation of pluripotent and multipotent cells could be a tool in both neural interface and tissue engineering. Here, we describe the potential of psPEF in directing neural stem cells (NSCs) gene expression, metabolism, and proliferation. As a comparison mesenchymal stem cells (MSCs) were also tested.

APPROACH

A psPEF electrode was anchored on a customized commercially available 3D printer, which allowed us to deliver pulses with high spatial precision and systematically control the electrode position in three-axes. When the electrodes are continuously energized and their position is shifted by the 3D printer, large numbers of cells on a surface can be exposed to a uniform psPEF. With two electric field strengths (20 and 40 kV cm^-1), cell responses, including cell viability, proliferation, and gene expression assays, were quantified and analyzed.

MAIN RESULTS

Analysis revealed both NSCs and MSCs showed no significant cell death after treatments. Both cell types exhibited an increased metabolic reduction; however, the response rate for MSCs was sensitive to the change of electric field strength, but for NSCs, it appeared independent of electric field strength. The change in proliferation rate was cell-type specific. MSCs underwent no significant change in proliferation whereas NSCs exhibited an electric field dependent response with the higher electric field producing less proliferation. Further, NSCs showed an upregulation of glial fibrillary acidic protein (GFAP) after 24 h to 40 kV cm^-1, which is characteristic of astrocyte specific differentiation.

SIGNIFICANCE

Changes in cell metabolism, proliferation, and gene expression after picosecond pulsed electric field exposure are cell type specific.

Characteristics of Nasal Septal Cartilage-Derived Progenitor Cells during Prolonged Cultivation

Objective To produce alternate cell sources for tissue regeneration, human nasal septal cartilage-derived progenitor cells (NSPs) were tested to identify whether these cells meet the criteria of cartilage progenitor cells. We also evaluated the effects of prolonged cultivation on the characteristics of NSPs. Study Design In vitro study. Setting Academic research laboratory. Methods NSPs were isolated from discarded human nasal septal cartilage. NSPs were cultured for 10 passages. The expression of septal progenitor cell surface markers was assessed by fluorescence-activated cell sorting. Cell proliferation was measured with a cell-counting kit. Cytokine secretion was analyzed with multiplex immunoassays. Chondrogenic differentiation of NSPs without differentiation induction was analyzed with type II collagen immunohistochemistry. Cartilage-specific protein expression was evaluated by Western blotting. Under osteo- and adipodifferentiation media, 2 lineage differentiation potentials were evaluated by histology and gene expression analysis. Results Surface epitope analysis revealed that NSPs are positive for mesenchymal stem cells markers and negative for hematopoietic cell markers. Cultured NSPs showed sufficient cell expansion and chondrogenic potential, as demonstrated by immunostaining and expression of cartilage-specific protein. IL-6, IL-8, and transforming growth factor ß were secreted by over 200 pg/mL. The osteo- and adipodifferentiation potentials of NSPs were identified by histology and specific gene expression. The aforementioned characteristics were not influenced by prolonged cultivation. Conclusion NSPs represent an initial step toward creating a cell source from surgically discarded tissue that may prove useful in cartilage regeneration.

Mesenchymal Stromal Cells and Cutaneous Wound Healing: A Comprehensive Review of the Background, Role, and Therapeutic Potential

Cutaneous wound repair is a highly coordinated cascade of cellular responses to injury which restores the epidermal integrity and its barrier functions. Even under optimal healing conditions, normal wound repair of adult human skin is imperfect and delayed healing and scarring are frequent occurrences. Dysregulated wound healing is a major concern for global healthcare, and, given the rise in diabetic and aging populations, this medicoeconomic disease burden will continue to rise. Therapies to reliably improve nonhealing wounds and reduce scarring are currently unavailable. Mesenchymal stromal cells (MSCs) have emerged as a powerful technique to improve skin wound healing. Their differentiation potential, ease of harvest, low immunogenicity, and integral role in native wound healing physiology make MSCs an attractive therapeutic remedy. MSCs promote cell migration, angiogenesis, epithelialization, and granulation tissue formation, which result in accelerated wound closure. MSCs encourage a regenerative, rather than fibrotic, wound healing microenvironment. Recent translational research efforts using modern bioengineering approaches have made progress in creating novel techniques for stromal cell delivery into healing wounds. This paper discusses experimental applications of various stromal cells to promote wound healing and discusses the novel methods used to increase MSC delivery and efficacy.

Nanomedicine and advanced technologies for burns: Preventing infection and facilitating wound healing

According to the latest report from the World Health Organization, an estimated 265,000 deaths still occur every year as a direct result of burn injuries. A widespread range of these deaths induced by burn wound happens in low- and middle-income countries, where survivors face a lifetime of morbidity. Most of the deaths occur due to infections when a high percentage of the external regions of the body area is affected. Microbial nutrient availability, skin barrier disruption, and vascular supply destruction in burn injuries as well as systemic immunosuppression are important parameters that cause burns to be susceptible to infections. Topical antimicrobials and dressings are generally employed to inhibit burn infections followed by a burn wound therapy, because systemic antibiotics have problems in reaching the infected site, coupled with increasing microbial drug resistance. Nanotechnology has provided a range of molecular designed nanostructures (NS) that can be used in both therapeutic and diagnostic applications in burns. These NSs can be divided into organic and non-organic (such as polymeric nanoparticles (NPs) and silver NPs, respectively), and many have been designed to display multifunctional activity. The present review covers the physiology of skin, burn classification, burn wound pathogenesis, animal models of burn wound infection, and various topical therapeutic approaches designed to combat infection and stimulate healing. These include biological based approaches (e.g. immune-based antimicrobial molecules, therapeutic microorganisms, antimicrobial agents, etc.), antimicrobial photo- and ultrasound-therapy, as well as nanotechnology-based wound healing approaches as a revolutionizing area. Thus, we focus on organic and non-organic NSs designed to deliver growth factors to burned skin, and scaffolds, dressings, etc. for exogenous stem cells to aid skin regeneration. Eventually, recent breakthroughs and technologies with substantial potentials in tissue regeneration and skin wound therapy (that are as the basis of burn wound therapies) are briefly taken into consideration including 3D-printing, cell-imprinted substrates, nano-architectured surfaces, and novel gene-editing tools such as CRISPR-Cas.

Role of mesenchymal stem cells in the pathogenesis of psoriasis: current perspectives

Mesenchymal stem cells (MSCs) are multipotent nonhematopoietic stromal cells studied for their properties and importance in management of several skin diseases. This review collects and analyzes the emerging published data, which describe the function of MSCs in the pathogenesis of psoriasis.

Extracellular Nucleotide Hydrolysis in Dermal and Limbal Mesenchymal Stem Cells: A Source of Adenosine Production

Human Limbal (L-MSCs) and Dermal Mesenchymal Stem Cell (D-MSCs) possess many properties that increase their therapeutic potential in ophthalmology and dermatology. It is known that purinergic signaling plays a role in many aspects of mesenchymal stem cells physiology. They release and respond to purinergic ligands, altering proliferation, migration, differentiation, and apoptosis. Therefore, more information on these processes would be crucial for establishing future clinical applications using their differentiation potential, but without undesirable side effects. This study evaluated and compared the expression of ecto-nucleotidases, the enzymatic activity of degradation of extracellular nucleotides and the metabolism of extracellular ATP in D-MSCs and L-MSCs, isolated from discard tissues of human skin and sclerocorneal rims. The D-MSCs and L-MSCs showed a differentiation potential into osteogenic, adipogenic, and chondrogenic lineages and the expression of markers CD105⁺ , CD44⁺ , CD14^- , CD34^- , CD45^- , as expected. Both cells hydrolyzed low levels of extracellular ATP and high levels of AMP, leading to adenosine accumulation that can regulate inflammation and tissue repair. These cells expressed mRNA for ENTPD1, 2, 3, 5 and 6, and CD73 that corresponded to the observed enzymatic activities. Thus, considering the degradation of ATP and adenosine production, limbal MSCs are very similar to dermal MSCs, indicating that from the aspect of extracellular nucleotide metabolism L-MSCs are very similar to the characterized D-MSCs. J. Cell. Biochem. 118: 2430-2442, 2017. © 2017 Wiley Periodicals, Inc.

Mesenchymal Stem Cell Therapy for Inflammatory Skin Diseases: Clinical Potential and Mode of Action

Inflammatory skin disorders that cause serious deterioration of the quality of life have become one of the major public concerns. Despite their significance, there is no fundamental cure to date. Mesenchymal stem cells (MSCs) possess unique immunomodulatory properties which make them a promising tool for the treatment of various inflammatory diseases. Our recent preclinical and clinical studies have shown that MSCs can be successfully used for the treatment of atopic dermatitis (AD), one of the major inflammatory skin diseases. This observation along with similar reports from other groups revealed the efficacy and underlying mechanisms of MSCs in inflammatory dermatosis. In addition, it has been proposed that cell priming or gene transduction can be novel strategies for the development of next-generation high-efficacy MSCs for treating inflammatory skin diseases. We discuss here existing evidence that demonstrates the regulatory properties of MSCs on immune responses under inflammatory conditions.

Mesenchymal stromal cells: properties and role in management of cutaneous diseases

This review describes the current understanding and the potential use of mesenchymal stromal cells (MSCs) in cell-based therapies for clinical management of difficult wounds and other dermatoses. MSCs have been shown to possess many advantageous properties that make them a promising therapeutic modality in dermatology still under investigation. In fact, MSCs' ability to promote wound healing through its paracrine function and pro-angiogenic properties have generated increasing interest for treating acute and chronic wounds. There is also great interest in utilizing MSCs' immunological characteristics for therapeutic use especially for patients with debilitating systemic autoimmune and inflammatory skin conditions who have failed other therapies. Its role in aesthetics has also been explored with clinical data showing improvement of acne scars and wrinkles from photoaging. Clinical trials are underway investigating the safety and efficacy of MSCs in the treatment of different skin conditions such as acute burns, diabetic and venous stasis ulcers, epidermolysis bullosa and systemic sclerosis, among others. We anticipate that as our understanding of the characteristics and function of MSCs grow, so will its role in cell-based treatments of dermatological conditions.

Toxic Epidermal Necrolysis in Recessive Dystrophic Epidermolysis Bullosa following Bone Marrow Transplantation

A 3-year-old child with recessive dystrophic epidermolysis bullosa treated with bone marrow transplantation subsequently developed body-wide epidermal detachment distinct from his epidermolysis bullosa. Toxic epidermal necrolysis was diagnosed by examination and skin biopsy. Although graft-vs-host disease was considered, he had no features of this diagnosis by laboratory studies or skin biopsy, and he improved without addition of further immune suppressants. Throughout the episode, the patient was maintained on cyclosporine A, a component of his transplant regimen, and also a reported therapy for toxic epidermal necrolysis. He had full recovery. Re-epithelialization occurred in a unique folliculocentric pattern, which we postulate was related to the patient's mesenchymal stem cell infusion, received as an adjunct to his marrow transplantation.

Mesenchymal Stromal Cell-Derived PTX3 Promotes Wound Healing via Fibrin Remodeling

Although mesenchymal stromal cells (MSCs) can promote wound healing in different clinical settings, the underlying mechanism of MSC-mediated tissue repair has yet to be determined. Because a nonredundant role of pentraxin 3 (PTX3) in tissue repair and remodeling has been recently described, here we sought to determine whether MSC-derived PTX3 might play a role in wound healing. Using a murine model of skin repair, we found that Ptx3-deficient (Ptx3(-/-)) MSCs delayed wound closure and reduced granulation tissue formation compared with wt MSCs. At day 2, confocal microscopy revealed a dramatic reduction in green fluorescent protein (GFP)-expressing Ptx3(-/-) MSCs recruited to the wound, where they appeared to be not only poorly organized in bundles but also scattered in the extracellular matrix. These findings were further confirmed by quantitative biochemical analysis of GFP content in wound extracts. Furthermore, Ptx3(-/-) MSC-treated skins displayed increased levels of fibrin and lower levels of D-dimer, suggesting delayed fibrin-rich matrix remodeling compared with control skins. Consistently, both pericellular fibrinolysis and migration through fibrin were found to be severely affected in Ptx3(-/-) MSCs. Overall, our findings identify an essential role of MSC-derived PTX3 in wound repair underscoring the beneficial potential of MSC-based therapy in the management of intractable wounds.

Epithelial expression of cytokeratins 15 and 19 in vitiligo

BACKGROUND

Cytokeratins (CK) belong to the family of intermediate filament proteins, and among them specific epithelial keratins are considered markers for stem cells activation.

OBJECTIVES

This study aims to investigate the expression of CK15 and CK19 as possible stem cell markers in vitiligo during phototherapy.

METHODS

The study was conducted on vitiligo patients receiving narrow-band ultraviolet therapy. Immunohistochemical staining for CK15 and CK19 was carried out, and clinical follow-up continued for 4 weeks.

RESULTS

Of 28 patients, CK15 expression was demonstrated in 17 cases (61%) while CK19 expression was demonstrated in 11 cases (39%). Cells expressing positive staining were demonstrated in follicular and interfollicular epithelium. Expression was clearly demonstrated in patients younger than 20 years old, with shorter disease duration, with disease stability, and with normally pigmented hairs. Expression of cytokeratins was significantly correlated to improvement of vitiligo lesions.

CONCLUSION

CK15 and CK19 are expressed in vitiligo during UV repigmentation in the follicular and interfollicular epithelium. This expression of cytokeratins was significantly correlated to improvement and can be considered valuable tool to monitor stem cells stimulation for the sake of the repigmentation process in vitiligo.

Cancer Microenvironment: What Can We Learn from the Stem Cell Niche

Epidermal stem cells (ESCs) are crucial for maintenance and self- renewal of skin epithelium and also for regular hair cycling. Their role in wound healing is also indispensable. ESCs reside in a defined outer root sheath portion of hair follicle—also known as the bulge region. ECS are also found between basal cells of the interfollicular epidermis or mucous membranes. The non-epithelial elements such as mesenchymal stem cell-like elements of dermis or surrounding adipose tissue can also contribute to this niche formation. Cancer stem cells (CSCs) participate in formation of common epithelial malignant diseases such as basal cell or squamous cell carcinoma. In this review article, we focus on the role of cancer microenvironment with emphasis on the effect of cancer-associated fibroblasts (CAFs). This model reflects various biological aspects of interaction between cancer cell and CAFs with multiple parallels to interaction of normal epidermal stem cells and their niche. The complexity of intercellular interactions within tumor stroma is depicted on example of malignant melanoma, where keratinocytes also contribute the microenvironmental landscape during early phase of tumor progression. Interactions seen in normal bulge region can therefore be an important source of information for proper understanding to melanoma. The therapeutic consequences of targeting of microenvironment in anticancer therapy and for improved wound healing are included to article.

TAT conjugated cationic noble metal nanoparticles for gene delivery to epidermal stem cells

Most nonviral gene delivery systems are not efficient enough to manipulate the difficult-to-transfect cell types, including non-dividing, primary, neuronal or stem cells, due to a lack of an intrinsic capacity to enter the membrane and nucleus, release its DNA payload, and activate transcription. Noble metal nanoclusters have emerged as a fascinating area of widespread interest in nanomaterials. Herein, we report the synthesis of the TAT peptide conjugated cationic noble metal nanoparticles (metal NPs@PEI-TAT) as highly efficient carriers for gene delivery to stem cells. The metal NPs@PEI-TAT integrate the advantages of metal NPs and peptides: the presence of metal NPs can effectively decrease the cytotoxicity of cationic molecules, making it possible to apply them in biological systems, while the cell penetrating peptides are essential for enhanced cellular and nucleus entry to achieve high transfection efficiency. Our studies provide strong evidence that the metal NPs@PEI-TAT can be engineered as gene delivery agents for stem cells and subsequently enhance their directed differentiation for biomedical application.

Erythropoietin, a novel repurposed drug: an innovative treatment for wound healing in patients with diabetes mellitus

Developing a new drug is expensive: the cost of going from bench to bedside is about $US1 billion. Therefore, the repurposing of an approved drug is potentially rewarding because it expands the drug's existing therapeutic profile and preempts additional development costs. As the safety profile of a repurposed drug is already well known, any new investigations could then focus on its efficacy and other therapeutic benefits. Recombinant erythropoietin (EPO) is a potential candidate for repurposing because the results of numerous studies have shown that systemic and topical EPO is therapeutically beneficial when it is administered to healthy and diabetic animals with acute and chronic skin wounds and burns. Moreover, the molecular mechanisms of EPO's actions have been elucidated: EPO acts on those nonhematopoietic cells which are involved in the innate immune response where it promotes cellular proliferation and differentiation, exerts its cytoprotective actions, and inhibits apoptosis. In this review, the mechanism of EPO's action in skin wound healing is reviewed, and its potential for treating acute and chronic skin wounds and stimulating tissue regeneration in diabetic patients is discussed.

Role of stem cells in the management of chronic wounds

Chronic wounds continue to be a major challenge for the medical profession, and plastic surgeons are frequently called in to help in the management of such wounds. Apart from the obvious morbidity to the patient, these problem wounds can be a major drain on the already scarce hospital resources. Sometimes, these chronic wounds can be more taxing than the underlying disease itself. Although many newer methods are available to handle such situations, the role of stem cells in the management of such wounds is an exciting area that needs to be explored further. A review of literature has been done regarding the role of stem cells in the management of chronic wounds. The abnormal pathology in such wounds is discussed and the possible role of stem cells for optimal healing in such cases would be detailed.

Human inferior turbinate: an alternative tissue source of multipotent mesenchymal stromal cells

OBJECTIVE

Mesenchymal stromal cells (MSCs) are multipotent progenitor cells in adult tissues. Current challenges for the clinical application of MSCs include donor site morbidity, which underscores the need to identify alternative sources of MSCs. This study aimed to explore potential new sources of multipotent MSCs for use in tissue regeneration and the functional restoration of organs.

STUDY DESIGN

Mixed methods research.

SETTING

Tertiary care center.

SUBJECTS AND METHODS

The authors isolated MSCs from human inferior turbinate tissues discarded during turbinate surgery of 10 patients for nasal obstruction. The expression of surface markers for MSCs was assessed by fluorescence-activated cell sorting. The differentiation potential of human turbinate mesenchymal stromal cells (hTMSCs) was analyzed by immunohistochemistry, reverse transcriptase-polymerase chain reaction, and Western blot analysis.

RESULTS

Surface epitope analysis revealed that hTMSCs were negative for CD14, CD19, CD34, and HLA-DR and positive for CD29, CD73, and CD90, representing a characteristic phenotype of MSCs. Extracellular matrices with characteristics of cartilage, bone, and adipose tissue were produced by inducing the chondrogenic, osteogenic, and adipogenic differentiation of hTMSCs, respectively. The expression of neuron-specific markers in hTMSCs was confirmed immunocytochemically.

CONCLUSION

The hTMSCs represent a new source of multipotent MSCs that are potentially applicable to tissue engineering and regenerative medicine. The availability of differentiated adult cells will allow the development of an effective tissue regeneration method.

Using stem cells in skin regeneration: possibilities and reality

Tissue-engineered skin has a long history of clinical applications, yet current treatments are not capable of completely regenerating normal, uninjured skin. Nonetheless, the field has experienced a tremendous development in the past 10 years, encountering the summit of tissue engineering (TE) and the arising of stem cell research. Since then, unique features of these cells such as self-renewal capacity, multi-lineage differentiation potential, and wound healing properties have been highlighted. However, a realistic perspective of their outcome in skin regenerative medicine applications is still absent. This review intends to discuss the directions that adult and embryonic stem cells (ESCs) can take, strengthening the skin regeneration field. Distinctively, a critical overview of stem cells' differentiation potential onto skin main lineages, along with a highlight of their participation in wound healing mechanisms, is herein provided. We aim to compile and review significant work to allow a better understanding of the best skin TE approaches, enabling the embodiment of the materialization of a new era in skin regeneration to come, with a conscious overview of the current limitations.

Great promise of tissue-resident adult stem/progenitor cells in transplantation and cancer therapies

Recent progress in tissue-resident adult stem/progenitor cell research has inspired great interest because these immature cells from your own body can act as potential, easily accessible cell sources for cell transplantation in regenerative medicine and cancer therapies. The use of adult stem/progenitor cells endowed with a high self-renewal ability and multilineage differentiation potential, which are able to regenerate all the mature cells in the tissues from their origin, offers great promise in replacing non-functioning or lost cells and regenerating diseased and damaged tissues. The presence of a small subpopulation of adult stem/progenitor cells in most tissues and organs provides the possibility of stimulating their in vivo differentiation, or of using their ex vivo expanded progenies for cell-replacement and gene therapies with multiple applications in humans without a high-risk of graft rejection and major side effects. Among the diseases that could be treated by adult stem cell-based therapies are hematopoietic and immune disorders, multiple degenerative disorders such as Parkinson's and Alzheimer's diseases, Types 1 and 2 diabetes mellitus as well as skin, eye, liver, lung, tooth and cardiovascular disorders. In addition, a combination of the current cancer treatments with an adjuvant treatment consisting of an autologous or allogeneic adult stem/progenitor cell transplantation also represents a promising strategy for treating and even curing diverse aggressive, metastatic, recurrent and lethal cancers. In this chapter, we reviewed the most recent advancements on the characterization of phenotypic and functional properties of adult stem/progenitor cell types found in bone marrow, heart, brain and other tissues and discussed their therapeutic implications in the stem cell-based transplantation therapy.

Upregulation of Adipogenesis and Chondrogenesis in MSC Serum-Free Culture

Serum-free media have been shown to be effective in the expansion of mesenchymal stem cells (MSCs). However, the effects may go beyond cell expansion as the differentiation potentials of the cells may be modified, thus influencing their efficacy for downstream applications. The latter is poorly understood, and this has prompted an evaluation of the influence of a serum-free formulation on the chondrogenic, adipogenic, and osteogenic potential of MSCs. The media consisted of Knockout™ Serum Replacement (KSR) with a cocktail of growth factors coupled with either collagen or fibronectin coatings. Collagen coating was selected as it promoted consistent cellular attachment. When compared against fetal bovine serum (FBS) controls, cell proliferation in the serum-free media was enhanced at passage 1. Similar levels of surface markers were observed in the two groups with a slight reduction in CD90 and CD73 in the serum-free culture at passage 3. The cultures were screened under differentiation conditions and a better maintenance of the chondrogenic potential was noted in the serum-free media with higher expressions of glycoaminoglycans (GAGs) and collagen II. Chondrogenesis was deficient in the FBS group and this was attributed to the inherent inconsistency of animal serum. Adipogenesis was enhanced in the serum-free group with a higher PPARG expression and lipid accumulation. Similar levels of osteogenic mineralization was noted in the FBS and serum-free groups but collagen I gene expression was suppressed in the latter. This was initially observed during expansion. These observations were attributed to the signaling cascades triggered by the cytokines presented in the serum-free formulation and the interaction with the collagen substrate. The serum-free media helps to maintain and enhance the chondrogenic and adipogenic potentials of the MSCs, respectively. This advantage can be exploited for therapeutic applications in cartilage and adipose tissue engineering.