Stromal progenitor cell therapy corrects the wound-healing defect in the ischemic rabbit ear model of chronic wound repair

Umbilical Cord Mesenchymal Stem Cell Therapy for Regenerative Treatment of Rheumatoid Arthritis: Opportunities and Challenges

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology with a high rate of disability. Traditional treatments for RA remain a challenging issue. For example, nonsteroidal anti-inflammatory drugs (NSAIDs) have no therapeutic effects on joint destruction, and the prominent side effects include gastrointestinal symptoms. RA is characterized by recurrence and bone attrition. Therefore, regenerative medicine and the use of umbilical cord mesenchymal stem cell (UC-MSC) therapies have recently emerged as potential options. UC-MSCs are multifunctional stem cells that are present in neonatal umbilical cord tissue and can differentiate into many kinds of cells, which have broad clinical application prospects in the tissue engineering of bone, cartilage, muscle, tendon, ligament, nerve, liver, endothelium, and myocardium. Moreover, UC-MSCs have advantages, such as convenient collection of materials and no ethical disputes; thus, these cells have attracted increasing attention from researchers. However, there are few clinical studies regarding UC-MSC therapy for RA. In this paper, we will review traditional drugs for RA treatment and then focus on UC-MSC therapy for RA, including preclinical and clinical UC-MSC applications for RA patients in the context of regenerative medicine. Finally, we will summarize the challenges and perspectives of UC-MSCs as a potential therapeutic strategy for RA. This review will help to design and discover more potent and efficacious treatments for RA patients and aid in advancing this class of cell therapy.

Nanostructured Cellulose-Gellan-Xyloglucan-Lysozyme Dressing Seeded with Mesenchymal Stem Cells for Deep Second-Degree Burn Treatment

PURPOSE

In deep burns, wound contraction and hypertrophic scar formation can generate functional derangement and debilitation of the affected part. In order to improve the quality of healing in deep second-degree burns, we developed a new treatment in a preclinical model using nanostructured membranes seeded with mesenchymal stem cells (MSCs).

METHODS

Membranes were obtained by reconstitution of bacterial cellulose (reconstituted membrane [RM]) and produced by a dry-cast process, then RM was incorporated with 10% tamarind xyloglucan plus gellan gum 1:1 and 10% lysozyme (RMGT-LZ) and with 10% gellan gum and 10% lysozyme (RMG-LZ). Membrane hydrophobic/hydrophilic characteristics were investigated by static/dynamic contact-angle measurements. They were cultivated with MSCs, and cell adhesion, proliferation, and migration capacity was analyzed with MTT assays. Morphological and topographic characteristics were analyzed by scanning electron microscopy. MSC patterns in flow cytometry and differentiation into adipocytes and osteocytes were checked. In vivo assays used RMG-LZ and RMGT-LZ (with and without MSCs) in Rattus norvegicus rats submitted to burn protocol, and histological sections and collagen deposits were analyzed and immunocytochemistry assay performed.

RESULTS

In vitro results demonstrated carboxyl and amine groups made the membranes moderately hydrophobic and xyloglucan inclusion decreased wettability, favoring MSC adhesion, proliferation, and differentiation. In vivo, we obtained 40% and 60% reduction in acute/chronic inflammatory infiltrates, 96% decrease in injury area, increased vascular proliferation and collagen deposition, and complete epithelialization after 30 days. MSCs were detected in burned tissue, confirming they had homed and proliferated in vivo.

CONCLUSION

Nanostructured cellulose-gellan-xyloglucan-lysozyme dressings, especially when seeded with MSCs, improved deep second-degree burn regeneration.

Mesenchymal stromal cells contract collagen more efficiently than dermal fibroblasts: Implications for cytotherapy

Background

Stem cell therapy is the next generation a well-established technique. Cell therapy with mesenchymal stem cells (MSC) has been demonstrated to enhance wound healing in diabetic mice, at least partly due to improved growth factor production. However, it is unclear whether MSC can biomechanically affect wound closure. Utilizing the well-established cell-populated collagen gel contraction model we investigated the interactions between MSC and the extracellular matrix.

Methods

Murine fetal liver-derived Mesenchymal Stem Cells (MSCs) or fetal Dermal Fibroblasts (DFs) were cultured in cell–populated collagen gels (CPCGs). The effect of cell density, conditioned media, growth factors (TGF-B1, FGF, PDGF-BB), cytoskeletal disruptors (colchicine, cytochalasin-D), and relative hypoxia on gel contraction were evaluated. Finally, we also measured the expression of integrin receptors and some growth factors by MSCs within the contracting gels.

Results

Our results show that at different densities, MSCs induced a higher gel contraction compared to DFs. Higher cell density resulted in faster and more complete contraction of CPCGs. Cytoskeletal inhibitors either inhibited or prevented MSC-mediated contraction in a dose dependent fashion. Growth factors, conditioned media from both MSC and DF, and hypoxia all influenced CPCG contraction.

Discussion

The results suggest that MSCs are capable of directly contributing to wound closure through matrix contraction, and they are more effective than DF. In addition, this study demonstrates the importance of how other factors such as cell concentration, cytokines, and oxygen tension can provide potential modulation of therapies to correct wound healing impairments.

IL-33-Dependent Group 2 Innate Lymphoid Cells Promote Cutaneous Wound Healing

Breaches in the skin barrier initiate an inflammatory immune response that is critical for successful wound healing. Innate lymphoid cells (ILCs) are a recently identified population of immune cells that reside at epithelial barrier surfaces such as the skin, lung and gut and promote pro-inflammatory or epithelial repair functions following exposure to allergens, pathogens or chemical irritants. However, the potential role of ILCs in regulating cutaneous wound healing remains undefined. Here, we demonstrate that cutaneous injury promotes an IL-33-dependent group 2 ILC (ILC2) response and that abrogation of this response impairs re-epithelialization and efficient wound closure. Additionally, we provide evidence suggesting that an analogous ILC2 response is operational in acute wounds of human skin. Together, these results indicate that IL-33-responsive ILC2s are an important link between the cutaneous epithelium and the immune system, acting to promote the restoration of skin integrity following injury.

Curbing Inflammation in Skin Wound Healing: A Review

Wound healing is a complex regulated process that results in skin scar formation in postnatal mammals. Chronic wounds are major medical problems that can confer devastating consequences. Currently, there are no treatments to prevent scarring. In the early fetus wounds heal without scarring and the healing process is characterized by relatively less inflammation compared to adults; therefore, research aimed at reducing the inflammatory process related to wound healing might speed healing and improve the final scar appearance.

Mesenchymal stem cell-based therapy for nonhealing wounds: today and tomorrow

Although advancements have been made with traditional therapies, the treatment of chronic nonhealing wounds still remains a tough challenge. In the past two decades, mesenchymal stem cell (MSC)-based therapy has emerged as a promising therapeutic strategy for nonhealing wounds because of their characteristics including self-renewal and a multidirectional differentiation ability and their easy collection and weak immunogenicity. There is a growing body of basic scientific studies that shed light on the functional mechanism of MSCs in modulating nonhealing wounds. Furthermore, critical advances have been achieved using MSC-based therapy in preclinical animal models as well as in clinics trials. In this present review, we summarize the mechanisms of MSCs and highlight the important preclinical and clinical trials of MSC therapy for nonhealing wounds. In particular, the combination of MSCs transplantation and tissue-engineered skin is addressed as a new strategy to optimize the delivery efficiency and therapeutic potential. Additionally, the current drawbacks of MSC therapy and the potential to further optimize the use of MSCs are implied.

Mesenchymal Stem Cells and Cutaneous Wound Healing: Current Evidence and Future Potential

Human skin is a remarkable organ that sustains insult and injury throughout life. The ability of skin to expeditiously repair wounds is paramount to survival. With an aging global population, coupled with a rise in the prevalence of conditions such as diabetes, chronic wounds represent a significant biomedical burden. Mesenchymal stem cells (MSC), a progenitor cell population of the mesoderm lineage, have been shown to be significant mediators in inflammatory environments. Preclinical studies of MSC in various animal wound healing models point towards a putative therapy. This review examines the body of evidence suggesting that MSC accelerate wound healing in both clinical and preclinical studies and also the possible mechanisms controlling its efficacy. The delivery of a cellular therapy to the masses presents many challenges from a safety, ethical, and regulatory point of view. Some of the issues surrounding the introduction of MSC as a medicinal product are also delineated in this review.

Xenogeneic Mesenchymal Stromal Cells Improve Wound Healing and Modulate the Immune Response in an Extensive Burn Model

Major skin burns are difficult to treat. Patients often require special care and long-term hospitalization. Besides specific complications associated with the wounds themselves, there may be impairment of the immune system and of other organs. Mesenchymal stromal cells (MSCs) are a recent therapeutic alternative to treat burns, mainly aiming to accelerate the healing process. Several MSC properties favor their use as therapeutic approach, as they promote angiogenesis, stimulate regeneration, and enhance the immunoregulatory function. Moreover, since patients with extensive burns require urgent treatment and because the expansion of autologous MSCs is a time-consuming process, in this present study we chose to evaluate the therapeutic potential of xenogeneic MSCs in the treatment of severe burns in rats. MSCs were isolated from mouse bone marrow, expanded in vitro, and intradermally injected in the periphery of burn wounds. MSC-treated rats presented higher survival rates (76.19%) than control animals treated with PBS (60.86%, p < 0.05). In addition, 60 days after the thermal injury, the MSC-treated group showed larger proportion of healed areas within the burn wounds (90.81 ± 5.05%) than the PBS-treated group (76.11 ± 3.46%, p = 0.03). We also observed that CD4(+) and CD8(+) T cells in spleens and in damaged skin, as well as the percentage of neutrophils in the burned area, were modulated by MSC treatment. Plasma cytokine (TGF-β, IL-10, IL-6, and CINC-1) levels were also altered in the MSC-treated rats, when compared to controls. Number of injected GFP(+) MSCs progressively decreased over time, and 60 days after injection, few MSCs were still detected in the skin of treated animals. This study demonstrates the therapeutic effectiveness of intradermal application of MSCs in a rat model of deep burns, providing basis for future regenerative therapies in patients suffering from deep burn injuries.

Combining xanthan and chitosan membranes to multipotent mesenchymal stromal cells as bioactive dressings for dermo-epidermal wounds

The association between tridimensional scaffolds to cells of interest has provided excellent perspectives for obtaining viable complex tissues in vitro, such as skin, resulting in impressive advances in the field of tissue engineering applied to regenerative therapies. The use of multipotent mesenchymal stromal cells in the treatment of dermo-epidermal wounds is particularly promising due to several relevant properties of these cells, such as high capacity of proliferation in culture, potential of differentiation in multiple skin cell types, important paracrine and immunomodulatory effects, among others. Membranes of chitosan complexed with xanthan may be potentially useful as scaffolds for multipotent mesenchymal stromal cells, given that they present suitable physico-chemical characteristics and have adequate tridimensional structure for the adhesion, growth, and maintenance of cell function. Therefore, the purpose of this work was to assess the applicability of bioactive dressings associating dense and porous chitosan-xanthan membranes to multipotent mesenchymal stromal cells for the treatment of skin wounds. The membranes showed to be non-mutagenic and allowed efficient adhesion and proliferation of the mesenchymal stromal cells in vitro. In vivo assays performed with mesenchymal stromal cells grown on the surface of the dense membranes showed acceleration of wound healing in Wistar rats, thus indicating that the use of this cell-scaffold association for tissue engineering purposes is feasible and attractive.

Interactions of the Extracellular Matrix and Progenitor Cells in Cutaneous Wound Healing

SIGNIFICANCE

Both chronic wounds and excessive scar formation after cutaneous injury create a formidable clinical problem resulting in considerable morbidity and healthcare expenditure. The deposition and remodeling of extracellular matrix (ECM) components are critical processes in cutaneous healing. Understanding the role of the ECM in directing progenitor and reparative cell fate and activities during wound repair is required to improve wound-care strategies.

RECENT ADVANCES

In addition to providing structural integrity, the ECM is recognized to play critical roles in regulating progenitor and reparative cell behaviors such as migration, differentiation, proliferation, and survival. The ECM dictates these activities through its binding of adhesion receptors as well as its ability to regulate growth factor bioavailability and signaling. More recently, a key role for mechanical control of cell fate through interaction with the ECM has emerged.

CRITICAL ISSUES

Despite significant advances in understanding the pathophysiology of cutaneous wound repair, problematic wounds remain a significant healthcare challenge. Regenerative medical strategies that either target endogenous stem cells or utilize applications of exogenous stem cell populations have emerged as promising approaches to pathologic wounds. However, the identification of smart biomaterials and matrices may allow for further optimization of such therapies.

FUTURE DIRECTIONS

An efficient and appropriate healing response in the skin postinjury is regulated by a fine balance of the quantity and quality of ECM proteins. A more complete understanding of ECM regulation of the cell fate and activities during cutaneous wound repair is vital for the development of novel treatment strategies for improvement of cutaneous healing.

Translating stem cell therapies: the role of companion animals in regenerative medicine

Veterinarians and veterinary medicine have been integral to the development of stem cell therapies. The contributions of large animal experimental models to the development and refinement of modern hematopoietic stem cell transplantation were noted nearly five decades ago. More recent advances in adult stem cell/regenerative cell therapies continue to expand knowledge of the basic biology and clinical applications of stem cells. A relatively liberal legal and ethical regulation of stem cell research in veterinary medicine has facilitated the development and in some instances clinical translation of a variety of cell-based therapies involving hematopoietic stem cells and mesenchymal stem cells, as well as other adult regenerative cells and recently embryonic stem cells and induced pluripotent stem cells. In fact, many of the pioneering developments in these fields of stem cell research have been achieved through collaborations of veterinary and human scientists. This review aims to provide an overview of the contribution of large animal veterinary models in advancing stem cell therapies for both human and clinical veterinary applications. Moreover, in the context of the "One Health Initiative," the role veterinary patients may play in the future evolution of stem cell therapies for both human and animal patients will be explored.

Effects of donor characteristics and ex vivo expansion on canine mesenchymal stem cell properties: implications for MSC-based therapies

Clinical trials utilizing bone marrow-derived mesenchymal stem cell (BM-MSC) therapies show promise for treating a variety of pathologic conditions. Paramount to optimization of such cell-based therapies is a thorough understanding of MSC biology. Despite the tremendous potential that exists for the clinical use of canine BM-MSCs in veterinary medicine, as well as in preclinical studies for human medicine, relatively little information exists regarding basic biological properties of the cells. In this study, we compared the importance of donor characteristics (age and harvest site) and ex vivo expansion on canine BM-MSC frequency (CFU-f) and differentiation potential. Advancing age was found to have a negative effect on CFU-f as well as osteogenic potential. Site of harvest was also found to have significant effects on MSC properties. MSCs obtained from the humerus were found at the lowest frequency and were least osteogenic compared to those harvested from the tibia, femur, and ilium. Osteogenic potential diminished significantly by the third passage. These results suggest important donor parameters and culture effects to consider in translational studies examining MSC-based regenerative medical strategies.

Diminished type III collagen promotes myofibroblast differentiation and increases scar deposition in cutaneous wound healing

The repair of cutaneous wounds in the postnatal animal is associated with the development of scar tissue. Directing cell activities to efficiently heal wounds while minimizing the development of scar tissue is a major goal of wound management and the focus of intensive research efforts. Type III collagen (Col3), expressed in early granulation tissue, has been proposed to play a prominent role in cutaneous wound repair, although little is known about its role in this process. To establish the role of Col3 in cutaneous wound repair, we examined the healing of excisional wounds in a previously described murine model of Col3 deficiency. Col3 deficiency (Col3+/-) in aged mice resulted in accelerated wound closure with increased wound contraction. In addition, Col3-deficient mice had increased myofibroblast density in the wound granulation tissue as evidenced by an increased expression of the myofibroblast marker, α-smooth muscle actin. In vitro, dermal fibroblasts obtained from Col3-deficient embryos (Col3+/- and -/-) were more efficient at collagen gel contraction and also displayed increased myofibroblast differentiation compared to those harvested from wild-type (Col3+/+) embryos. Finally, wounds from Col3-deficient mice also had significantly more scar tissue area on day 21 post-wounding compared to wild-type mice. The effect of Col3 expression on myofibroblast differentiation and scar formation in this model suggests a previously undefined role for this ECM protein in tissue regeneration and repair.

In vivo Differentiation Potential of Mesenchymal Stem Cells: Prenatal and Postnatal Model Systems

SUMMARY: Most of our knowledge of mesenchymal stem cell (MSC) biology is derived from in vitro systems that are often highly contrived to favor culture expansion or specific differentiation events. However, any conclusions drawn from in vitro studies regarding MSC differentiation capacity, immune properties, or therapeutic potential must be validated by in vivo studies to ultimately be meaningful. At the present time, there are relatively few in vivo studies demonstrating differentiation and functional integration of MSCs into host tissues after transplantation. There is a need for in vivo model systems to assay MSC biology and to move potential therapeutic strategies forward. Here, we review prenatal model systems as potentially advantageous for the in vivo characterization of MSCs, and we critically review the results of in vivo studies of MSC transplantation in prenatal and postnatal model systems with an emphasis on proven engraftment and differentiation.