Stem cells and their applications in skin-cell therapy

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.

Therapeutic strategies of three-dimensional stem cell spheroids and organoids for tissue repair and regeneration

Three-dimensional (3D) stem cell culture systems have attracted considerable attention as a way to better mimic the complex interactions between individual cells and the extracellular matrix (ECM) that occur in vivo. Moreover, 3D cell culture systems have unique properties that help guide specific functions, growth, and processes of stem cells (e.g., embryogenesis, morphogenesis, and organogenesis). Thus, 3D stem cell culture systems that mimic in vivo environments enable basic research about various tissues and organs. In this review, we focus on the advanced therapeutic applications of stem cell-based 3D culture systems generated using different engineering techniques. Specifically, we summarize the historical advancements of 3D cell culture systems and discuss the therapeutic applications of stem cell-based spheroids and organoids, including engineering techniques for tissue repair and regeneration.

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.

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.

Comparative characterization of sun exposed and sun protected skin-derived mesenchymal-like stem cells in variegate porphyria and healthy individuals

BACKGROUND AND PURPOSE

We hypothesized that upon sun exposure, a sub-population of primary skin-derived mesenchymal-like cells is deleteriously affected and thus contribute to the chronic inflammatory state in autosomal recessive variegate porphyria patients. The aim of this study was to isolate and characterize the mesenchymal-like stem cells from different areas of the skin in a porphyria patient (sun exposed, SE, and sun protected, SP) and to compare them with cells from a healthy individual.

METHODS

The proliferation rate and the migration ability of SE and SP cells were evaluated in the presence of an antioxidant compound, N-acetylcysteine. A co-culture of SE-damaged cells with the conditioned medium from the enriched mesenchymal cell-like SP population was performed in order to regenerate the dermal injured tissue after sun exposure in patients.

RESULTS

Results showed that the percentage of CD105⁺ cells varies between 3.9% in SP and 5% in SE of the healthy individual and between 3.6% and 1.4% in SP and SE in the porphyria patient, respectively. The osteogenic differentiation potential was lower in the porphyria patient when compared to the control. Furthermore, the expression of stem cell markers was more pronounced in SE than in SP cells of both control and porphyria. The use of N-acetyl cysteine did not show any beneficial effects on porphyria SE cells. Treatment with SP-conditioned medium slightly increased the expression of stem cell markers in SE of porphyria patient.

CONCLUSION

In conclusion, the pool of mesenchymal stem-like SE cells is affected in variegate porphyria patient along with modification of their self-renewal and differentiation properties.

Advances in the Research of Bioinks Based on Natural Collagen, Polysaccharide and Their Derivatives for Skin 3D Bioprinting

The skin plays an important role in protecting the human body, and wound healing must be set in motion immediately following injury or trauma to restore the normal structure and function of skin. The extracellular matrix component of the skin mainly consists of collagen, glycosaminoglycan (GAG), elastin and hyaluronic acid (HA). Recently, natural collagen, polysaccharide and their derivatives such as collagen, gelatin, alginate, chitosan and pectin have been selected as the matrix materials of bioink to construct a functional artificial skin due to their biocompatible and biodegradable properties by 3D bioprinting, which is a revolutionary technology with the potential to transform both research and medical therapeutics. In this review, we outline the current skin bioprinting technologies and the bioink components for skin bioprinting. We also summarize the bioink products practiced in research recently and current challenges to guide future research to develop in a promising direction. While there are challenges regarding currently available skin bioprinting, addressing these issues will facilitate the rapid advancement of 3D skin bioprinting and its ability to mimic the native anatomy and physiology of skin and surrounding tissues in the future.

Physicochemically Tuned Myofibroblasts for Wound Healing Strategy

Normal healing of skin wounds involves a complex interplay between many different cellular constituents, including keratinocytes, immune cells, fibroblasts, myofibroblasts, as well as extracellular matrices. Especially, fibroblasts play a critical role in regulating the immune response and matrix reconstruction by secreting many cytokines and matrix proteins. Myofibroblasts, which are differentiated form of fibroblasts, feature high cellular contractility and encourage the synthesis of matrix proteins to promote faster closure of the wounds. We focus on the functional characteristics of these myofibroblasts as the healing strategy for severe wounds where the surplus amount of matrix proteins could be beneficial for better regeneration. In this study, we first employed multiple physicochemical cues, namely topographical alignment, TGF-β1, and electrical field (EF), to induce differentiation of dermal fibroblasts into myofibroblasts, and to further activate the differentiated cells. We then used these cells in a mouse wound model to verify their potential as a transplantable substitute for the severe wound. Our results confirmed that physicochemically stimulated myofibroblasts promoted faster healing of the wound compared to the case with non-stimulated myofibroblasts through elevated matrix reconstruction in the mouse model. Conclusively, we propose the utilization of physicochemically tuned myofibroblasts as a novel strategy for promoting better healing of moderate to severe wounds.

Eminent Sources of Adult Mesenchymal Stem Cells and Their Therapeutic Imminence

In the recent times, stem cell biology has garnered the attention of the scientific fraternity and the general public alike due to the immense therapeutic potential that it holds in the field of regenerative medicine. A breakthrough in this direction came with the isolation of stem cells from human embryo and their differentiation into cell types of all three germ layers. However, the isolation of mesenchymal stem cells from adult tissues proved to be advantageous over embryonic stem cells due to the ethical and immunological naivety. Mesenchymal Stem Cells (MSCs) isolated from the bone marrow were found to differentiate into multiple cell lineages with the help of appropriate differentiation factors. Furthermore, other sources of stem cells including adipose tissue, dental pulp, and breast milk have been identified. Newer sources of stem cells have been emerging recently and their clinical applications are also being studied. In this review, we examine the eminent sources of Mesenchymal Stem Cells (MSCs), their immunophenotypes, and therapeutic imminence.

Stem cell therapy on skin: Mechanisms, recent advances and drug reviewing issues

Stem cell products and its clinical applications have been widely discussed in recent years, particularly when the Japanese “induced pluripotent stem cells” founder Dr. Yamanaka was awarded as Nobel Prize laureate in 2013. For decades, major progresses have been achieved in the stem cell biology field, and more and more evidence showed that skin stem cells are involved in the process of skin repair. Stem/progenitor cells of the epidermis are recognized to play the most essential role in the tissue regeneration of skin. In this review, we first illustrated basic stem cell characteristics and various stem cell subtypes resided in the skin. Second, we provided several literatures to elucidate how stem/progenitor cells collaborate in the process of skin repair with the evidence from animal model studies and in vitro experiments. Third, we also introduced several examples of skin cell products on the pharmaceutic market and the ongoing clinical trials aiming for unmet medical difficulties of skin. Last but not least, we summarized general reviewing concerns and some disputatious issues on dermatological cell products. With this concise review, we hope to provide further beneficial suggestions for the development of more effective and safer dermatological stem/progenitor cell products in the future.

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.

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.

Epidermal stem cells (ESCs) accelerate diabetic wound healing via the Notch signalling pathway

Epidermal stem cells (ESCs) accelerate diabetic wound healing via the Notch signalling pathway.

Chronic, non-healing wounds are a major complication of diabetes. Recently, various cell therapies have been reported for promotion of diabetic wound healing. Epidermal stem cells (ESCs) are considered a powerful tool for tissue therapy. However, the effect and the mechanism of the therapeutic properties of ESCs in the diabetic wound healing are unclear. Herein, to determine the ability of ESCs to diabetic wound healing, a dorsal skin defect in a streptozotocin (STZ)-induced diabetes mellitus (DM) mouse model was used. ESCs were isolated from mouse skin. We found that both the mRNA and protein levels of a Notch ligand Jagged1 (Jag1), Notch1 and Notch target gene Hairy Enhancer of Split-1 (Hes1) were significantly increased at the wound margins. In addition, we observed that Jag1 was high expressed in ESCs. Overexpression of Jag1 promotes ESCs migration, whereas knockdown Jag1 resulted in a significant reduction in ESCs migration in vitro. Importantly, Jag1 overexpression improves diabetic wound healing in vivo. These results provide evidence that ESCs accelerate diabetic wound healing via the Notch signalling pathway, and provide a promising potential for activation of the Notch pathway for the treatment of diabetic wound.

Cell-based regenerative strategies for treatment of diabetic skin wounds, a comparative study between human umbilical cord blood-mononuclear cells and calves' blood haemodialysate

BACKGROUND

Diabetes-related foot problems are bound to increase. However, medical therapies for wound care are limited; therefore, the need for development of new treatment modalities to improve wound healing in diabetic patients is essential and constitutes an emerging field of investigation.

METHODS

Animals were randomly divided into 8 groups (I-VIII) (32 rats/group), all were streptozotocin (STZ)-induced diabetics except groups III and VIII were non-diabetic controls. The study comprised two experiments; the first included 3 groups. Group I injected with mononuclear cells (MNCs) derived from human umbilical cord blood (HUCB), group II a diabetic control group (PBS i.v). The second experiment included 5 groups, groups IV, V, and VI received topical HUCB-haemodialysate (HD), calves' blood HD, and solcoseryl, respectively. Group VII was the diabetic control group (topical saline). Standard circular wounds were created on the back of rats. A sample of each type of HD was analyzed using the high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) system. Wound area measurement and photography were carried out every 4 days. Plasma glucose, catalase (CAT), malondialdehyde (MDA), nitric oxide (NO) and platelets count were assessed. Wound samples were excised for hydroxyproline (HP) and histopathological study.

RESULTS

Treatment with HUCB MNCs or HUCB-HD resulted in wound contraction, increased CAT, NO, platelets count, body weights, and HP content, and decreased MDA and glucose.

CONCLUSION

Systemic administration of HUCB MNCs and topical application of the newly prepared HUCB-HD or calves' blood HD significantly accelerated the rate of diabetic wound healing and would open the possibility of their future use in regenerative medicine.

The immunosuppressive properties of non-cultured dermal-derived mesenchymal stromal cells and the control of graft-versus-host disease

Mesenchymal stromal cells (MSCs) have been developed for the prevention and treatment of graft-versus-host disease (GVHD). Non-cultured natural MSCs are considered ideal, as they better maintain their biological and therapeutic properties. The skin is the largest organ in the body and constitutes an interesting alternative to bone marrow for the generation of MSCs. Large numbers of dermal-derived-MSCs (DMSCs) can be easily generated without culturing in vitro, but their therapeutic effects still remain unclear. In this study, we described for the first time the use of non-cultured DMSCs for controlling GVHD in an MHC-mismatched mouse model and investigated their immunomodulatory effects. Our results showed that non-cultured mouse DMSCs decreased the incidence and severity of acute GVHD during MHC-mismatched stem cell transplantation in mice. This effect was mediated by the inhibition of splenic cell (SPC) proliferation and the enhancement of Treg cells. Consistent with the results in vivo, the results in vitro showed that human DMSCs inhibited the proliferation of peripheral blood mononuclear cells (PBMCs) by inhibiting the proliferation of CD3(+) T cells. hDMSCs prevented PBMCs from entering S phase, suppressed the activation of CD3(+) T cells and increased Treg proportions. In conclusion, DMSCs should be considered as a novel MSC source for the control of refractory GVHD.

The therapeutic potential of mesenchymal stem cell-derived extracellular vesicles

Extracellular vesicles (EVs), membrane vesicles that are secreted by a variety of mammalian cell types, have been shown to play an important role in intercellular communication. The contents of EVs, including proteins, microRNAs, and mRNAs, vary according to the cell type that secreted them. Accordingly, researchers have demonstrated that EVs derived from various cell types play different roles in biological phenomena. Considering the ubiquitous presence of mesenchymal stem cells (MSCs) in the body, MSC-derived EVs may take part in a wide range of events. In particular, MSCs have recently attracted much attention due to the therapeutic effects of their secretory factors. MSC-derived EVs may therefore provide novel therapeutic approaches. In this review, we first summarize the wide range of functions of EVs released from different cell types, emphasizing that EVs echo the phenotype of their parent cell. Then, we describe the various therapeutic effects of MSCs and pay particular attention to the significance of their paracrine effect. We then survey recent reports on MSC-derived EVs and consider the therapeutic potential of MSC-derived EVs. Finally, we discuss remaining issues that must be addressed before realizing the practical application of MSC-derived EVs, and we provide some suggestions for enhancing their therapeutic efficiency.

Melanocyte stem cells: biology and current aspects

Epidermal stem cells have become an object of intensive research. The epidermis constitutes one of the main sources of stem cells and is a tissue of choice for use in exploring their biology.

Stratified squamous epithelium (epidermis) possesses the capacity for self-renewal and repair due to the presence of epidermal stem cells (ESC). They have been identified within basal layer of the interfollicular epidermis (IFE), in the “bulge” of the hair follicles of rodents, and also in the human follicular bulge. Melanocyte stem cells (MSC) from hair follicles (precisely from the bulge region, which also contains epidermal stem cells) provide an attractive model for the study of stem cells and their regulation at the niche.

This review summarizes the rapidly developing field of epidermal stem cell research and their application in regenerative medicine, paying particular attention to melanocyte stem cells, their biology and some of the processes that occur during hair graying and regeneration of the pigmentary system, as well as discussing how aged-associated changes in the melanocyte stem cells compartment impact hair graying. This review also includes differentiation of human skin stem cells into functional epidermal melanocytes.

Mesenchymal stem cell-like cells from children foreskin inhibit the growth of SGC-7901 gastric cancer cells

Mesenchymal stem cells (MSCs) become a research hotspot in recent years because of their roles in regenerative medicine and tissue injury repair. However, the limited source for MSCs hampers its clinical application. In this study, we isolated and identified human mesenchymal stem cell-like cells from foreskin (hFMSCs) by explant culture. HFMSCs had similar morphology and immunophenotype to that of human bone marrow derived-mesenchymal stem cells. HFMSCs formed colonies after 9 days of inoculation and could be propagated for more than 50 passages. HFMSCs had a normal karyotype and high G0/G1 phase independent of passage number. Further, hFMSCs could be induced to differentiate into osteocytes and adipocytes. We found that the growth of SGC-7901 (human gastric adenocarcinoma) cells could be suppressed by simultaneous injection of hFMSCs in vivo. HFMSCs also inhibited SGC-7901 cell proliferation in vitro. HFMSC co-injection resulted in a decrease in PCNA-positive and an increase in apoptotic tumor cells. HFMSCs derived conditioned medium inhibited the expression of BCL-2 while increased the expression of BAX and caspase-3 in SGC-7901 cells. Taken together, our findings suggest that children foreskin is a new source for MSCs and hFMSCs could inhibit gastric cancer cell growth both in vitro and in vivo.

Analysis of transferred keratinocyte-like cells derived from mouse embryonic stem cells on experimental surgical skin wounds of mouse

Autologous/allogenic skin grafts constituted from differentiated adult or embryonic stem cells can be used in treatment of skin disorders. In our study we aimed to differentiate keratinocytes from mouse embryonic stem cells and the transfer of viable keratinocyte-like cells to a model of surgical skin wound of mouse. Embryoid bodies, derived from mouse embryonic stem cells, were cultured on basement membrane matrix with added BMP-4 for 10 days. The identification of differentiated keratinocyte-like cells was done by detection of cytokeratin-8 and cytokeratin-14 localization using an indirect immunoperoxidase technique and transmission electron microscopy evaluation. Distribution of BrdU, cytokeratin-8 and cytokeratin-14 were evaluated using an indirect immunoperoxidase technique from the experimental (dressing including BrdU labelled cells applied after the surgical wound was created on mouse), control (only the surgical wound was created on mouse) and sham (only the dressing applied after the surgical wound was created on mouse) in groups after 3, 5 and 7 days. Immunohistochemically and ultrastructurally, cells derived from mouse embryonic stem cells were similar to differentiated keratinocyte-like cells. Differentiated keratinocyte-like cells were demonstrated by positive BrdU, cytokeratin-8 and cytokeratin-14 staining after transfer to the wound area. In the experimental group wound healing was better after transferring differentiated keratinocytes when compared to the sham and control groups. In vivo continuity and usability of derived cells are very important issues. In wound repair mechanisms, keratinocyte-like cells could provide positive effects during the wound healing and could be used in clinical treatments of wound repair process.

Role of autologous mesenchymal stem cells associated with platelet-rich plasma on healing of cutaneous wounds in diabetic mice

BACKGROUND

Chronic cutaneous lesions affect 15% of human patients with diabetes, and the associated risk of limb amputations is 15-46 times greater than that of people with normal glycaemia. It is estimated that half of these limb amputations could be avoided by opportune treatment with somatic stem cells or platelet-rich plasma (PRP).

METHODS

We evaluated the effects of autologous transplant of mesenchymal stem cells (MSCs) with or without combination with autologous PRP in the re-epithelialization of cutaneous lesions induced in diabetic mice.

RESULTS

Animals treated with MSCs alone showed a similar level of re-epithelialization of cutaneous lesions to those treated with MSC plus PRP, and no significant difference was found between the two treatments.

CONCLUSION

Both treatments gave better results than daily cleaning of the cutaneous lesions with saline or covering of the lesions with semipermeable adherent bandage.

Stem cell applications in military medicine

There are many similarities between health issues affecting military and civilian patient populations, with the exception of the relatively small but vital segment of active soldiers who experience high-energy blast injuries during combat. A rising incidence of major injuries from explosive devices in recent campaigns has further complicated treatment and recovery, highlighting the need for tissue regenerative options and intensifying interest in the possible role of stem cells for military medicine. In this review we outline the array of tissue-specific injuries typically seen in modern combat - as well as address a few complications unique to soldiers - and discuss the state of current stem cell research in addressing each area. Embryonic, induced-pluripotent and adult stem cell sources are defined, along with advantages and disadvantages unique to each cell type. More detailed stem cell sources are described in the context of each tissue of interest, including neural, cardiopulmonary, musculoskeletal and sensory tissues, with brief discussion of their potential role in regenerative medicine moving forward. Additional commentary is given to military stem cell applications aside from regenerative medicine, such as blood pharming, immunomodulation and drug screening, with an overview of stem cell banking and the unique opportunity provided by the military and civilian overlap of stem cell research.

Mesenchymal stem cell characteristics of human anterior cruciate ligament outgrowth cells

When ruptured, the anterior cruciate ligament (ACL) of the human knee has limited regenerative potential. However, the goal of this report was to show that the cells that migrate out of the human ACL constitute a rich population of progenitor cells and we hypothesize that they display mesenchymal stem cell (MSC) characteristics when compared with adherent cells derived from bone marrow or collagenase digests from ACL. We show that ACL outgrowth cells are adherent, fibroblastic cells with a surface immunophenotype strongly positive for cluster of differentiation (CD)29, CD44, CD49c, CD73, CD90, CD97, CD105, CD146, and CD166, weakly positive for CD106 and CD14, but negative for CD11c, CD31, CD34, CD40, CD45, CD53, CD74, CD133, CD144, and CD163. Staining for STRO-1 was seen by immunohistochemistry but not flow cytometry. Under suitable culture conditions, the ACL outgrowth-derived MSCs differentiated into chondrocytes, osteoblasts, and adipocytes and showed capacity to self-renew in an in vitro assay of ligamentogenesis. MSCs derived from collagenase digests of ACL tissue and human bone marrow were analyzed in parallel and displayed similar, but not identical, properties. In situ staining of the ACL suggests that the MSCs reside both aligned with the collagenous matrix of the ligament and adjacent to small blood vessels. We conclude that the cells that emigrate from damaged ACLs are MSCs and that they have the potential to provide the basis for a superior, biological repair of this ligament.

Comparative characterization of porcine mesenchymal stem cells derived from bone marrow extract and skin tissues

Mesenchymal stem cells (MSCs) offer a great promise for regenerative medicine. Present study compared the characterization of porcine MSCs (pMSCs) derived from bone marrow extract with adult ear and fetal skin-derived cells on morphology, cell growth, alkaline phosphatase activity, proliferation ability, expression of cluster of differentiation (CD) markers (CD29, 45, and 90), cell cycle, protein and mRNA levels of Oct-4, Sox-2, and Nanog, and lineage differentiation ability. Skin-derived cells exhibited alkaline phosphatase activity and differentiation ability like pMSCs. pMSCs possessed a longer doubling time than skin-derived cells, and there was no difference in the ratio of G0/G1 phase between pMSCs and skin-derived cells. Except for CD29 and 90, all cells were found negative for CD45. Protein and mRNA expression of Oct-4, Sox-2 and Nanog were observed with similar intensity in all cells. Taken together, pMSCs and skin-derived cells revealed similar characteristics, and suggested the possible supportive role of skin-derived cells with MSCs for the regeneration of damaged tissues in cell-based therapies.

Peripheral nerve regeneration using autologous porcine skin-derived mesenchymal stem cells

Porcine skin-derived mesenchymal stem cells (pSMSCs) were evaluated on their biological MSC characterizations and differentiation into mesenchymal lineages, along with in vitro and in vivo neural inductions. Isolated pSMSCs showed plate-adherent growth, expression of various MSC-marker proteins and transcriptional factors, and differentiation potential into mesenchymal lineages. Neuron-like cell morphology and various neural markers were highly detected at 6 h and 24 h after in vitro neural induction of pSMSCs, but their neuron-like characteristics disappeared as induction time extended to 48 and 72 h. To evaluate the in vivo peripheral nerve regeneration potential of pSMSCs, a total of 5 × 10(6) autologous pSMSCs labelled with tracking dye, supplemented with fibrin glue scaffold and collagen tubulization, were transplanted into the peripheral nerve defected miniature pigs. At 2 and 4 weeks after cell transplantation, well-preserved transplanted cells and remarkable in vivo nerve regeneration, including histologically complete nerve bundles, were observed in the regenerated nerve tissues. Moreover, S-100 protein and p75 nerve growth factor receptor were more highly detected in regenerated nerve fibres compared to non-cell grafted control fibres. These results suggest that autologous pSMSCs transplanted with fibrin glue scaffold can induce prominent nerve regeneration in porcine peripheral nerve defect sites.

Skin regeneration with bone marrow-derived cell populations

Bone marrow-derived cells of distinct differentiation level could differently influence the process of skin regeneration. The results of our study revealed that hematopoietic stem cells (HSC) population influenced the repair of injured tissue slower in comparison with lineage negative (lin⁻) cell population containing not only HSC but also cell progenitors of different differentiation levels. Wound healing process was faster in lin⁻) cell suspension treated group, the stage of proliferation was more intensive and increased number of skin appendages occurred. The adaptation of purified HSC at the site of injury was longer and the stages of wound healing took place later. The results obtained show that in further experiments the complex procedure of HSC isolation and purification could be shortened and heavy skin injuries could be successfully treated with the help of lin⁻ cell population.

Multipotent mesenchymal stem cell grafting to treat cutaneous radiation syndrome: development of a new minipig model

OBJECTIVE

Cutaneous radiation syndrome (CRS) is the delayed consequence of localized skin exposure to high doses of ionizing radiation. Recent grafting of three ionizing radiation-burned patients has suggested the benefit of local bone marrow mesenchymal stem cell (MSC) injection in favor of wound healing and pain control. Here, we have developed a new minipig model of severe CRS to study underlying mechanisms of this cell therapy approach.

MATERIALS AND METHODS

Göttingen minipigs were locally irradiated using a (60)Co gamma source as follows: ungrafted 50 and 60 Gy (n = 4) and grafted 50 and 60 Gy (n = 3). Bone marrow MSCs were cultured in minimum essential medium with 10% fetal calf serum and basic fibroblast growth factor (2 ng.mL(-1)). Autologous MSCs were intradermally injected twice or three times from days 27 to 96 (range, 99-128.5 × 10(6) MSCs per injection).

RESULTS

All animals exhibited a clinical evolution similar to humans after a latency phase of several weeks, including early erythema, hair loss, and dry/moist desquamation followed by necrosis during 81 to 222 days post-ionizing radiation. Skin damage in higher exposed animals appeared slightly earlier. Immunohistology revealed severe skin damage in all animals and rhabdomyolysis in the muscle tissue below the entry area, with the latter being more severe in controls. In grafted animals, MSCs led to local accumulation of lymphocytes at the dermis/subcutis border and improved vascularization.

CONCLUSIONS

This study establishes a new minipig model that is close to human and allows development of stem cell therapy strategies that can be applied in treatment of human radiation burns.

In vitro and in vivo osteogenesis of porcine skin-derived mesenchymal stem cell-like cells with a demineralized bone and fibrin glue scaffold

In vitro and in vivo osteogenesis of skin-derived mesenchymal stem cell-like cells (SDMSCs) with a demineralized bone (DMB) and fibrin glue scaffold were compared. SDMSCs isolated from the ears of adult miniature pigs were evaluated for the expression of transcriptional factors (Oct-4, Sox-2, and Nanog) and MSC marker proteins (CD29, CD44, CD90, and vimentin). The isolated SDMSCs were cocultured in vitro with a mixed DMB and fibrin glue scaffold in a nonosteogenic medium for 1, 2, and 4 weeks. Osteonectin, osteocalcin, and Runx2 were expressed during the culture period and reached maximum at 2 weeks after in vitro coculture. von Kossa-positive bone minerals were also noted in the cocultured medium at 4 weeks. Autogenous porcine SDMSCs (1 x 10(7)) labeled with a tracking dye, PKH26, were grafted into the maxillary sinus with a DMB and fibrin glue scaffold. In the contralateral side, only a scaffold was grafted without SDMSCs (control). In vivo osteogenesis was evaluated from two animals euthanized at 2 and 4 weeks after grafting. In vivo PKH26 staining was detected in all the specimens at both time points. Trabecular bone formation and osteocalcin expression were more pronounced around the grafted materials in the SDMSC-grafted group compared with the control group. New bone generation was initiated from the periphery to the center of the grafted material. The number of proliferating cells increased over time and reached a peak at 4 weeks in both in vivo and in vitro specimens. These findings suggest that autogenous SDMSC grafting with a DMB and fibrin glue scaffold can serve as a predictable alternative to bone grafting in the maxillary sinus floor.

Beta2-microglobulin: emerging as a promising cancer therapeutic target

Beta2-microglobulin, a MHC class I subunit, is found to act similarly to a prototypical oncogenic factor capable of stimulating growth and progression of various cancers and plays a key regulatory role in stimulating cancer bone metastasis. Free beta2M in serum or urine has been regarded as an independent biomarker in several cancers. Specific antibodies to beta2M have remarkable tumoricidal activity for both solid tumors and blood malignancies and are shown to be selective to tumor cells, but caused no toxicity in normal cells. These surprising data strongly suggest that beta2M is a promising new therapeutic target for human cancers.

The evolutionary origin of the Runx/CBFbeta transcription factors--studies of the most basal metazoans

Background

Members of the Runx family of transcriptional regulators, which bind DNA as heterodimers with CBFβ, are known to play critical roles in embryonic development in many triploblastic animals such as mammals and insects. They are known to regulate basic developmental processes such as cell fate determination and cellular potency in multiple stem-cell types, including the sensory nerve cell progenitors of ganglia in mammals.

Results

In this study, we detect and characterize the hitherto unexplored Runx/CBFβ genes of cnidarians and sponges, two basal animal lineages that are well known for their extensive regenerative capacity. Comparative structural modeling indicates that the Runx-CBFβ-DNA complex from most cnidarians and sponges is highly similar to that found in humans, with changes in the residues involved in Runx-CBFβ dimerization in either of the proteins mirrored by compensatory changes in the binding partner. In situ hybridization studies reveal that Nematostella Runx and CBFβ are expressed predominantly in small isolated foci at the base of the ectoderm of the tentacles in adult animals, possibly representing neurons or their progenitors.

Conclusion

These results reveal that Runx and CBFβ likely functioned together to regulate transcription in the common ancestor of all metazoans, and the structure of the Runx-CBFβ-DNA complex has remained extremely conserved since the human-sponge divergence. The expression data suggest a hypothesis that these genes may have played a role in nerve cell differentiation or maintenance in the common ancestor of cnidarians and bilaterians.

Spontaneous transformation of a clonal population of dermis-derived multipotent cells in culture

It is reported that adult multipotent stem cells can undergo spontaneous transformation after long-term in vitro culture. Understanding the molecular mechanisms involved in this spontaneous transformation process can help in the design of future therapeutic applications. By far, the transformation process of adult multipotent stem cell is not well understood. In this study, a tumorigenic cell line nominated TDMC1 was established from a clonal population of rat dermis-derived multipotent cells (DMCs) following spontaneous transformation in culture. The transformed cells could produce tumors with characteristics of fibrous histocytoma when they are inoculated subcutaneously into nude mice. The molecular profiles of the nontransformed DMCs and transformed cells were analyzed by a deoxyribonucleic acid microarray. Our results showed that the overactivation of the K-ras/mitogen-activated protein kinase kinase signaling pathway played an important role in the transformation process. These data may be helpful to explain, at least in part, the possible mechanism for the malignant transformation of adult multipotent cells.

Microengineered surface topography facilitates cell grafting from a prototype hydrogel wound dressing with antibacterial capability

Skin wounds derive therapeutic benefit from redeployment of dermal tissues, whether as split-thickness allo- and autografts or as biological dressings comprising cultured cells. However, the clinical outcome is strongly influenced by the techniques used for cell/tissue grafting and also the microbiological status of the wound. Here we report that microtopography incorporated into the surface of a novel polymeric material, derivatized with fibronectin to promote attachment and encourage motility, improved the efficiency of cell transfer onto de-epithelialized human skin ex vivo. The microtopography had two functions, first as a conduit for migrating cells to cross between the vehicle and recipient surface and second to shield adherent cells from destruction by mechanical shearing during handling and application. Quantitative analysis showed that topographic projections (columns) rather than recesses (pits) in the hydrogel surface achieved the highest efficiency of cell transfer. In order to address the crucial relevance of microbiological contamination to the success of wound grafting, the effect of iodine on several common bacterial pathogens was examined using an XTT+C(Q10) kinetic cell viability assay. Increasing concentrations of iodine initially stressed and after 0.5% v/v were subsequently bacteriocidal for Gram-negative Pseudomonas aeruginosa and Escherichia coli and Gram-positive Bacillus subtillis and Staphylococcus aureus. Slightly higher doses of iodine (approx 1-1.5% v/v) were required to kill HaCaT cells outright, but for both pro- and eukaryotes the major determinant of cytotoxicity was absolute dose rather than duration of exposure. Iodine delivered by the hydrogel at low concentration was bacteriostatic but not apparently cytotoxic to epithelial cells as measured by MTT end-point cell viability assay. Zone of inhibition studies confirmed that bacteriocidal quantities of neomycin, phenol red, and silver could also be delivered using the same hydrogel. This research suggests that grafting cell-based biological dressings to wounds using a topographically modified hydrogel dressing capable of simultaneous reducing the microbiological threat to a successful outcome may be a realistic clinical proposition.