Use of Human Cadaveric Mesenchymal Stem Cells for Cell Therapy of a Chronic Radiation-Induced Skin Lesion: A Case Report

Targeting the NLRP3 in macrophages contributes to senescence cell clearance in radiation-induced skin injury

BACKGROUND

The persistent accumulation of senescence cells is one of the characteristics of radiation-induced skin injury (RISI), leading to fibrosis and impaired healing. However, the reasons why these senescence cells are resistant to clearance remain unclear.

METHODS

The mouse RISI model was established using an X-ray generator, and a shield was used to cover all areas except the skin of the right leg or back for protecting surrounding tissue. ScRNA sequencing, immunohistochemistry, immunofluorescence, qPCR, western blot, primary cell co-culture system and fluorescence microsphere phagocytosis assay were performed for the functional and mechanistic investigations.

RESULTS

The dynamic changes of senescence cell levels and multiple immune cell levels during RISI were evaluated, we found that macrophages could remove senescence cells from the dermis, and the clearance ability gradually strengthens over time. ScRNA sequencing revealed that macrophages with high senescence clearance capacity exhibited increased NOD-like receptor family pyrin domain-containing 3 (NLRP3) expression compared to those with low senescence clearance capacity. Inhibition or conditional knockout of Nlrp3 in macrophages led to senescence cell clearance dysfunction and impaired healing. Further studies found that interleukin-33 secreted by senescence cells inhibited the expression of NLRP3 in macrophages and their ability to phagocytize senescence cells, especially in the early stages after radiation. In addition, Nocardia rubra cell wall skeleton (Nr-CWS), an approved immunomodulator, was found to activate macrophage NLRP3 expression, reduce senescence cell burden, and accelerate the healing of RISI.

CONCLUSION

This study underscored NLRP3 in macrophages as a critical intervention target for senescence cell immunosurveillance and emphasized Nr-CWS as a potential therapeutic agent for accelerating senescence cell clearance in RISI.

Navigating the Complexities of Radiation Injuries: Therapeutic Principles and Reconstructive Strategies

Radiation injuries, particularly those resulting from therapeutic or accidental exposure, present complex challenges for medical management. These injuries can manifest localized skin damage or extend to deeper tissues, presenting as various clinical entities that require treatment strategies, ranging from conservative management to complex surgical interventions. Radiation treatment constitutes a fundamental component of neoplastic management, with nearly two out of three oncological instances undergoing it as an element of their therapeutic strategy. The therapeutic approach to radiation injury consists of expanding prophylactic measures while maintaining the efficacy of treatment, such as conservative treatment or local debridement followed by reconstruction. The armamentarium of reconstructive methods available for plastic surgeons, from secondary healing to free tissue transfer, can be successfully applied to radiation injuries. However, the unique pathophysiological changes induced by radiation necessitate a careful and specialized approach for their application, considering the altered tissue characteristics and healing dynamics. The therapeutic strategy is guided by both the severity and progression of the injury, with the primary aim of restoring functionality and aesthetic aspects while simultaneously minimizing the risk of complications. This paper explores the various conditions encompassed by the term "radiation injury," reviews both non-surgical and surgical therapeutic strategies for managing these injuries, and highlights the unique challenges associated with treating irradiated tissues within specific oncological contexts.

Advancements in cell-based therapies for thermal burn wounds: a comprehensive systematic review of clinical trials outcomes

BACKGROUND

Burn trauma is one of the major causes of morbidity and mortality worldwide. The standard management of burn wounds consists of early debridement, dressing changes, surgical management, and split-thickness skin autografts (STSGs). However, there are limitations for the standard management that inclines us to find alternative treatment approaches, such as innovative cell-based therapies. We aimed to systematically review the different aspects of cell-based treatment approaches for burn wounds in clinical trials.

METHODS

A systematic search through PubMed, Medline, Embase, and Cochrane Library databases was carried out using a combination of keywords, including "Cell transplantation", "Fibroblast", "Keratinocyte", "Melanocyte", or "Stem Cell" with "Burn", "Burn wound", or "Burn injury". Firstly, titles and abstracts of the studies existing in these databases until "February 2024" were screened. Then, the selected studies were read thoroughly, and considering the inclusion and exclusion criteria, final articles were included in this systematic review. Moreover, a manual search was performed through the reference lists of the included studies to minimize the risk of missing reports.

RESULTS

Overall, 30 clinical trials with 970 patients were included in our study. Considering the type of cells, six studies used keratinocytes, nine used fibroblasts, eight used combined keratinocytes and fibroblasts, one study used combined keratinocytes and melanocytes, five used combined keratinocytes and fibroblasts and melanocytes, and one study used mesenchymal stem cells (MSCs). Evaluation of the preparation type in these studies showed that cultured method was used in 25 trials, and non-cultured method in 5 trials. Also, the graft type of 17 trials was allogeneic, and of 13 other trials was autologous.

CONCLUSIONS

Our study showed that employing cell-based therapies for the treatment of burn wounds have significant results in clinical studies and are promising approaches that can be considered as alternative treatments in many cases. However, choosing appropriate cell-based treatment for each burn wound is essential and depends on the situation of each patient.

Different Biocompatibility and Radioprotective Activity of Squid Melanin Nanoparticles on Human Stromal Cells

Squid ink melanin nanoparticles (NPs) have recently been demonstrated to have a number of bioactivities; however, their biocompatibility has been poorly investigated. In this study, we aimed to evaluate the effects of this NP on stromal cells, including human fibroblasts (hFBs), human umbilical vein endothelial cells (hUVECs), and human umbilical cord-derived mesenchymal stem cells (UCMSCs), and on the development of zebrafish embryos under normal X-ray irradiation conditions. The NPs showed high biocompatibility with low cytotoxicity, no cell senescence induction, and no effect on cell migration in hFBs or cell differentiation in UCMSCs. Nonetheless, this compound prevented cell movement in UCMSCs and significantly suppressed tube formation in hUVECs at a dose of 25 μg/mL. The NPs successfully penetrated the hUVECs but not the other two stromal cell types. The expression levels of functional genes involved in angiogenesis, apoptosis, antioxidant activity, and radiation sensitivity were altered in NPs subjected to hUVECs but were not affected in hFBs and UCMSCs. Melanin NPs significantly rescued cell viability and gene expression in irradiated hFBs and UCMSCs but not in hUVECs. In vivo treatments of zebrafish embryos showed that melanin NPs were nontoxic whether alone or under X-ray irradiation. These findings suggested that nanosized squid ink melanin had biocompatibility with selective stromal cells and was safe for early development.

Combined treatment of umbilical cord Wharton's jelly-derived mesenchymal stem cells and platelet-rich plasma for a surgical patient with hospital-acquired pressure ulcer: a case report and literature review

Hospital-acquired pressure ulcers (HAPUs) are still an important worldwide issue related to the safety and quality of patient care, which are among the top five adverse events reported. Patients who develop HAPUs have longer stays in the hospital than necessary, are at a greater risk of infections, and are more likely to die. Surgical patients are prone to developing PUs because they often remain immobile for extended periods of time, and their surgical procedures may limit the flow of blood oxygen and nutrition and lead to a decrease in muscle tone. Mesenchymal stem cells (MSCs) represent an attractive stem cell source for tissue regeneration in clinical applications, which have been demonstrated to improve wound healing through re-epithelialization, increased angiogenesis, and granulation tissue formation. Here, we present the case of an emergency surgical patient who developed an ulcer on the right heel during hospitalization. The human umbilical cord Wharton's jelly-derived MSCs (WJ-MSCs) re-suspended in platelet-rich plasma (PRP) were injected into ulcer margins. Four days after the WJ-MSC application, the patient showed progressive healing of the PU. From days 4 to 33, granulation tissue formation and re-epithelialization were clearly observed. The ulcer was almost healed completely on day 47, and the pain in the patient's wound area also decreased. Thus, intradermal transplantation of WJ-MSCs and PRP was safe and effective for treatment in patients with pressure ulcers. WJ-MSCs, together with PRP, may offer a promising treatment option for wound healing.

Mesenchymal Stromal Cell Healing Outcomes in Clinical and Pre-Clinical Models to Treat Pressure Ulcers: A Systematic Review

BACKGROUND

Despite numerous measures used to prevent pressure ulcers, their growing prevalence in recent years is expected to continue as the population ages. This review aims to report the outcomes of the regenerative potential of MSCs in treating pressure ulcers, assessing the effectiveness of MSCs in treating pressure ulcers.

METHODS

A computerized search for articles on animal models that use MSCs as primary therapy to treat pressure ulcers, published from conception to present, was conducted using PubMed, MEDLINE, Embase, and CINAHL. Our search yielded 52 articles, narrowed to 44 after excluding duplicates.

RESULTS

Out of 52 articles collected from four databases, 11 met the inclusion criteria. A total of 11 articles published between 2008 and 2020 met the inclusion criteria. Eight studies were observational descriptive papers in animal models, and three were prospective. Six studies used autologous MSCs, while five used allogenic MSCs. Three studies were conducted in humans, and the remaining eight were conducted in animals. The most common method of cell delivery was an intradermal injection in the margins of the ulcer. All studies reported positive results, including improved wound healing, reduced inflammation, and improved tissue regeneration.

CONCLUSIONS

MSCs have shown promising results in treating pressure ulcers in animal and clinical trials. The combination of MSCs and scaffold materials has also been studied and found to be effective in wound healing. A standardized human wound model has been proposed further to investigate the efficacy of cell-based therapies for chronic wounds. However, more research is needed to determine the best quantity of cells to apply for pressure ulcers and to ensure the safety and efficacy of these treatments in clinical settings.

The effect of chemotherapy and radiotherapy on stem cells and wound healing. Current perspectives and challenges for cell-based therapies

Cancers are part of the group of diseases that carry a high mortality rate. According to World Health Organization in 2020 reported 10 million deaths due to cancers. Treatment of oncological patients is focused on chemotherapeutic agents, radiology, or immunology. Surgical interventions are also an important aspect of treatment. The above methods contribute to saving the patients' health and lives. However, cancer treatment possesses side effects. Commonly observed complications are hair loss, mucositis, nausea, diarrhea, or various skin damage. To improve the quality of medical care for cancer patients, new methods of reducing side effects are sought. Strategies include the use of stem cells (SCs). Due to unlimited proliferation potential and differentiating abilities, SCs are used in the treatment of many disease entities, including wounds. One of the most used types of stem cells supposed adipose-derived mesenchymal stromal cells (AD-MSCs). Clinical trials confirm the application of AD-MSCs in wound healing. Furthermore, in vivo studies considered the utilization of AD-MSCs in radiation injury. The use of stem cells in cancer treatment still involves many questions, such as the impact of treatment on SCs' condition and oncological safety. However, development in regenerative medicine research may contribute to the use of stem cells in personalized medicine, customized for the patient. This could represent a breakthrough step in preventing the side effects of cancer therapies, including chronic wounds.

Orchestration of Mesenchymal Stem/Stromal Cells and Inflammation During Wound Healing

Wound healing is a complex process and encompasses a number of overlapping phases, during which coordinated inflammatory responses following tissue injury play dominant roles in triggering evolutionarily highly conserved principals governing tissue repair and regeneration. Among all nonimmune cells involved in the process, mesenchymal stem/stromal cells (MSCs) are most intensely investigated and have been shown to play fundamental roles in orchestrating wound healing and regeneration through interaction with the ordered inflammatory processes. Despite recent progress and encouraging results, an informed view of the scope of this evolutionarily conserved biological process requires a clear understanding of the dynamic interplay between MSCs and the immune systems in the process of wound healing. In this review, we outline current insights into the ways in which MSCs sense and modulate inflammation undergoing the process of wound healing, highlighting the central role of neutrophils, macrophages, and T cells during the interaction. We also draw attention to the specific effects of MSC-based therapy on different pathological wound healing. Finally, we discuss how ongoing scientific advances in MSCs could be efficiently translated into clinical strategies, focusing on the current limitations and gaps that remain to be overcome for achieving preferred functional tissue regeneration.

Revolutionizing Radiotoxicity Management with Mesenchymal Stem Cells and Their Derivatives: A Focus on Radiation-Induced Cystitis

Although radiation therapy plays a crucial role in cancer treatment, and techniques have improved continuously, irradiation induces side effects in healthy tissue. Radiation cystitis is a potential complication following the therapeutic irradiation of pelvic cancers and negatively impacts patients' quality of life (QoL). To date, no effective treatment is available, and this toxicity remains a therapeutic challenge. In recent times, stem cell-based therapy, particularly the use of mesenchymal stem cells (MSC), has gained attention in tissue repair and regeneration due to their easy accessibility and their ability to differentiate into several tissue types, modulate the immune system and secrete substances that help nearby cells grow and heal. In this review, we will summarize the pathophysiological mechanisms of radiation-induced injury to normal tissues, including radiation cystitis (RC). We will then discuss the therapeutic potential and limitations of MSCs and their derivatives, including packaged conditioned media and extracellular vesicles, in the management of radiotoxicity and RC.

The Therapeutic Application of Stem Cells and Their Derived Exosomes in the Treatment of Radiation-Induced Skin Injury

Radiation-induced skin injury (RISI) is a serious concern for nuclear accidents and cancer radiotherapy, which seriously affects the quality of life of patients. This injury differs from traditional wounds due to impaired healing and the propensity to recurrence and is divided into acute and chronic phases on the basis of the injury time. Unfortunately, there are few effective therapies for preventing or mitigating this injury. Over the last few decades, various studies have focused on the effects of stem cell-based therapies to address the tissue repair and regeneration of irradiated skin. These stem cells modulate inflammation and instigate tissue repair by differentiating into specific kinds of cells or releasing paracrine factors. Stem cell-based therapies, including bone marrow-derived stem cells (BMSCs), adipose-derived stem cells (ADSCs) and stromal vascular fraction (SVF), have been reported to facilitate wound healing after radiation exposure. Moreover, stem cell-derived exosomes have recently been suggested as an effective and cell-free approach to support skin regeneration, circumventing the concerns respecting direct application of stem cells. Based on the literature on stem cell-based therapies for radiation-induced skin injury, we summarize the characteristics of different stem cells and describe their latest animal and clinical applications, as well as potential mechanisms. The promise of stem-cell based therapies against radiation-induced skin injury contribute to our response to nuclear events and smooth progress of cancer radiotherapy.

Convergence of Biofabrication Technologies and Cell Therapies for Wound Healing

BACKGROUND

Cell therapy holds great promise for cutaneous wound treatment but presents practical and clinical challenges, mainly related to the lack of a supportive and inductive microenvironment for cells after transplantation. Main: This review delineates the challenges and opportunities in cell therapies for acute and chronic wounds and highlights the contribution of biofabricated matrices to skin reconstruction. The complexity of the wound healing process necessitates the development of matrices with properties comparable to the extracellular matrix in the skin for their structure and composition. Over recent years, emerging biofabrication technologies have shown a capacity for creating complex matrices. In cell therapy, multifunctional material-based matrices have benefits in enhancing cell retention and survival, reducing healing time, and preventing infection and cell transplant rejection. Additionally, they can improve the efficacy of cell therapy, owing to their potential to modulate cell behaviors and regulate spatiotemporal patterns of wound healing.

CONCLUSION

The ongoing development of biofabrication technologies promises to deliver material-based matrices that are rich in supportive, phenotype patterning cell niches and are robust enough to provide physical protection for the cells during implantation.

Differential Cytotoxicity of Curcumin-Loaded Micelles on Human Tumor and Stromal Cells

Although curcumin in the form of nanoparticles has been demonstrated as a potential anti-tumor compound, the impact of curcumin and nanocurcumin in vitro on normal cells and in vivo in animal models is largely unknown. This study evaluated the toxicity of curcumin-loaded micelles in vitro and in vivo on several tumor cell lines, primary stromal cells, and zebrafish embryos. Breast tumor cell line (MCF7) and stromal cells (human umbilical cord vein endothelial cells, human fibroblasts, and human umbilical cord-derived mesenchymal stem cells) were used in this study. A zebrafish embryotoxicity (FET) assay was conducted following the Organisation for Economic Co-operation and Development (OECD) Test 236. Compared to free curcumin, curcumin PM showed higher cytotoxicity to MCF7 cells in both monolayer culture and multicellular tumor spheroids. The curcumin-loaded micelles efficiently penetrated the MCF7 spheroids and induced apoptosis. The nanocurcumin reduced the viability and disturbed the function of stromal cells by suppressing cell migration and tube formation. The micelles demonstrated toxicity to the development of zebrafish embryos. Curcumin-loaded micelles demonstrated toxicity to both tumor and normal primary stromal cells and zebrafish embryos, indicating that the use of nanocurcumin in cancer treatment should be carefully investigated and controlled.

Urine-Derived Stem Cells for Epithelial Tissues Reconstruction and Wound Healing

Epithelial tissue injury can occur on any surface site of the body, particularly in the skin or urethral mucosa tissue, due to trauma, infection, inflammation, and toxic compounds. Both internal and external body epithelial tissue injuries can significantly affect patients’ quality of life, increase healthcare spending, and increase the global economic burden. Transplantation of epithelial tissue grafts is an effective treatment strategy in clinical settings. Autologous bio-engineered epithelia are common clinical skin substitutes that have the specific advantages of avoiding tissue rejection, obviating ethical concerns, reducing the risk of infection, and decreasing scarring compared to donor grafts. However, epithelial cells are often obtained from the individual’s skin and mucosa through invasive methods, which cause further injury or damage. Urine-derived stem cells (USC) of kidney origin, obtained via non-invasive acquisition, possess high stemness properties, self-renewal ability, trophic effects, multipotent differentiation potential, and immunomodulatory ability. These cells show versatile potential for tissue regeneration, with extensive evidence supporting their use in the repair of epidermal and urothelial injuries. We discuss the collection, isolation, culture, characterization, and differentiation of USC. We also discuss the use of USC for cellular therapies as well as the administration of USC-derived paracrine factors for epidermal and urothelial tissue repair. Specifically, we will discuss 3D constructions involving multiple types of USC-loaded hydrogels and USC-seeded scaffolds for use in cosmetic production testing, drug development, and disease modeling. In conclusion, urine-derived stem cells are a readily accessible autologous stem cell source well-suited for developing personalized medical treatments in epithelial tissue regeneration and drug testing.

Human Mesenchymal Stromal Cells Do Not Cause Radioprotection of Head-and-Neck Squamous Cell Carcinoma

Radiotherapy of head-and-neck squamous cell carcinoma (HNSCC) can cause considerable normal tissue injuries, and mesenchymal stromal cells (MSCs) have been shown to aid regeneration of irradiation-damaged normal tissues. However, utilization of MSC-based treatments for HNSCC patients undergoing radiotherapy is hampered by concerns regarding potential radioprotective effects. We therefore investigated the influence of MSCs on the radiosensitivity of HNSCCs. Several human papillomavirus (HPV)-negative and HPV-positive HNSCCs were co-cultured with human bone marrow-derived MSCs using two-dimensional and three-dimensional assays. Clonogenic survival, proliferation, and viability of HNSCCs after radiotherapy were assessed depending on MSC co-culture. Flow cytometry analyses were conducted to examine the influence of MSCs on irradiation-induced cell cycle distribution and apoptosis induction in HNSCCs. Immunofluorescence stainings of γH2AX were conducted to determine the levels of residual irradiation-induced DNA double-strand breaks. Levels of connective tissue growth factor (CTGF), a multifunctional pro-tumorigenic cytokine, were analyzed using enzyme-linked immunosorbent assays. Neither direct MSC co-culture nor MSC-conditioned medium exerted radioprotective effects on HNSCCs as determined by clonogenic survival, proliferation, and viability assays. Consistently, three-dimensional microwell arrays revealed no radioprotective effects of MSCs. Irradiation resulted in a G2/M arrest of HNSCCs at 96 h independently of MSC co-culture. HNSCCs’ apoptosis rates were increased by irradiation irrespective of MSCs. Numbers of residual γH2AX foci after irradiation with 2 or 8 Gy were comparable between mono- and co-cultures. MSC mono-cultures and HNSCC-MSC co-cultures exhibited comparable CTGF levels. We did not detect radioprotective effects of human MSCs on HNSCCs. Our results suggest that the usage of MSC-based therapies for radiotherapy-related toxicities in HNSCC patients may be safe in the context of absent radioprotection.

Cadaveric Stem Cells: Their Research Potential and Limitations

In the era of growing interest in stem cells, the availability of donors for transplantation has become a problem. The isolation of embryonic and fetal cells raises ethical controversies, and the number of adult donors is deficient. Stem cells isolated from deceased donors, known as cadaveric stem cells (CaSCs), may alleviate this problem. So far, it was possible to isolate from deceased donors mesenchymal stem cells (MSCs), adipose delivered stem cells (ADSCs), neural stem cells (NSCs), retinal progenitor cells (RPCs), induced pluripotent stem cells (iPSCs), and hematopoietic stem cells (HSCs). Recent studies have shown that it is possible to collect and use CaSCs from cadavers, even these with an extended postmortem interval (PMI) provided proper storage conditions (like cadaver heparinization or liquid nitrogen storage) are maintained. The presented review summarizes the latest research on CaSCs and their current therapeutic applications. It describes the developments in thanatotranscriptome and scaffolding for cadaver cells, summarizes their potential applications in regenerative medicine, and lists their limitations, such as donor’s unknown medical condition in criminal cases, limited differentiation potential, higher risk of carcinogenesis, or changing DNA quality. Finally, the review underlines the need to develop procedures determining the safe CaSCs harvesting and use.

Transplantation of the Stromal Vascular Fraction (SVF) Mitigates Severe Radiation-Induced Skin Injury

Severe radiation-induced skin injury is a complication of tumor radiotherapy and nuclear accidents. Cell therapy is a potential treatment for radiation-induced skin injury. The stromal vascular fraction (SVF) is a newer material in stem cell therapy that is made up of stem cells harvested from adipose tissue, which has been shown to promote the healing of refractory wounds of different causes. In this study, SVF was isolated from patients with radiation-induced skin injury. Adipose-derived stem cells (ADSCs) accounted for approximately 10% of the SVF by flow cytometry. Compared with the control group of rats, administration with SVF attenuated the skin injury induced by electron beam radiation. The effect of SVF on the human skin fibroblast microenvironment was determined by proteomic profiling of secreted proteins in SVF-co-cultured human skin fibroblast WS1 cells. Results revealed 293 upregulated and 1,481 downregulated proteins in the supernatant of SVF-co-cultured WS1 cells. WS1 co-culture with SVF induced secretion of multiple proteins including collagen and MMP-1. In the clinic, five patients with radiation-induced skin injury were recruited to receive SVF transfer-based therapy, either alone or combined with flap transplantation. Autogenous SVF was isolated and introduced into a multi-needle precision electronic injection device, which automatically and aseptically distributed the SVF to the exact layer of the wound in an accurate amount. After SVF transfer, wound healing clearly improved and pain was significantly relieved. The patients' skin showed satisfactory texture and shape with no further wound recurrence. Our findings suggest that transplantation of SVF could be an effective countermeasure against severe radiation-induced skin injury.

Will mesenchymal stem cells be future directions for treating radiation-induced skin injury?

Radiation-induced skin injury (RISI) is one of the common serious side effects of radiotherapy (RT) for patients with malignant tumors. Mesenchymal stem cells (MSCs) are applied to RISI repair in some clinical cases series except some traditional options. Though direct replacement of damaged cells may be achieved through differentiation capacity of MSCs, more recent data indicate that various cytokines and chemokines secreted by MSCs are involved in synergetic therapy of RISI by anti-inflammatory, immunomodulation, antioxidant, revascularization, and anti-apoptotic activity. In this paper, we not only discussed different sources of MSCs on the treatment of RISI both in preclinical studies and clinical trials, but also summarized the applications and mechanisms of MSCs in other related regenerative fields.

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

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

Mesenchymal Stem Cells for Mitigating Radiotherapy Side Effects

Radiation therapy for cancers also damages healthy cells and causes side effects. Depending on the dosage and exposure region, radiotherapy may induce severe and irreversible injuries to various tissues or organs, especially the skin, intestine, brain, lung, liver, and heart. Therefore, promising treatment strategies to mitigate radiation injury is in pressing need. Recently, stem cell-based therapy generates great attention in clinical care. Among these, mesenchymal stem cells are extensively applied because it is easy to access and capable of mesodermal differentiation, immunomodulation, and paracrine secretion. Here, we summarize the current attempts and discuss the future perspectives about mesenchymal stem cells (MSCs) for mitigating radiotherapy side effects.

Local Treatment of Burns with Cell-Based Therapies Tested in Clinical Studies

Effective wound management is an important determinant of the survival and prognosis of patients with severe burns. Thus, novel techniques for timely and full closure of full-thickness burn wounds are urgently needed. The purpose of this review is to present the current state of knowledge on the local treatment of burn wounds (distinguishing radiation injury from other types of burns) with the application of cellular therapies conducted in clinical studies. PubMed search engine and ClinicalTrials.gov were used to analyze the available data. The analysis covered 49 articles, assessing the use of keratinocytes (30), keratinocytes and fibroblasts (6), fibroblasts (2), bone marrow-derived cells (8), and adipose tissue cells (3). Studies on the cell-based products that are commercially available (Epicel^®, Keraheal™, ReCell^®, JACE, Biobrane^®) were also included, with the majority of reports found on autologous and allogeneic keratinocytes. Promising data demonstrate the effectiveness of various cell-based therapies; however, there are still scientific and technical issues that need to be solved before cell therapies become standard of care. Further evidence is required to demonstrate the clinical efficacy and safety of cell-based therapies in burns. In particular, comparative studies with long-term follow-up are critical.

Low-intensity ultrasound combined with allogenic adipose-derived mesenchymal stem cells (AdMSCs) in radiation-induced skin injury treatment

Mesenchymal stem cells are mechano-sensitive cells with the potential to restore the function of damaged tissues. Low-intensity ultrasound has been increasingly considered as a bioactive therapeutic apparatus. Optimizing transplantation conditions is a critical aim for radiation-induced skin tissue injury. Therefore, the therapeutic function of adipose-derived mesenchymal stem cells to ultrasound stimulus was examined based on the mechanical index (MI). Mesenchymal stem cells were isolated from the adipose tissues of mature guinea pigs. An ultrasound system (US) was constructed with a 40 kHz frequency. The radiation-induced skin injury model was produced on the abdominal skin of guinea pigs by 60 Gy of radiation. Then, they were divided to 7 groups (n = 42): control, sham, US (MI = 0.7), AdMSCs injection, US AdMSCs (AdMSCs, under US with MI = 0.2), AdMSCs + US (AdMSCs transplantation and US with MI = 0.7) and US AdMSCs + US (combining the last two groups). The homing of stem cells was verified with fluorescence imaging. The groups were followed with serial photography, ultrasound imaging, tensiometry, and histology. The thickness of the skin was analyzed. Functional changes in skin tissue were evaluated with Young's modulus (kPa). One-way ANOVA tests were performed to analyze differences between treatment protocols (p < 0.05). The results of Kumar's score showed that radiation injury was significantly lower in the treatment groups of US AdMSCs and US AdMSCs + US than other groups after 14 days (p < 0.05). There was a significant difference in skin thickness between treatment groups with control, sham, and US groups after 60 Gy radiation and were closer to the thickness of healthy skin. Young's modulus in US AdMSCs + US, US AdMSCs, and AdMSCs + US groups demonstrated a significant difference with the other groups (p < 0.05). Young's modulus in US AdMSCs + US and US AdMSCs treatment groups were closer to Young's modulus of the healthy skin. The histological results confirmed the improvement of acute radiation damage in the combined treatment method, especially in US AdMSCs + US and US AdMSCs groups with increasing the epithelialization and formation of collagen. An ultrasonic treatment plan based on a mechanical index of the target medium could be used to enhance stem cell therapy.

Mesenchymal Stem Cells for Chronic Wound Healing: Current Status of Preclinical and Clinical Studies

Healing skin wounds with anatomic and functional integrity, especially under chronic pathological conditions, remain an enormous challenge. Due to their outstanding regenerative potential, mesenchymal stem cells (MSCs) have been explored in many studies to determine the healing ability for difficult-to-treat diseases. In this article, we review current animal studies and clinical trials of MSC-based therapy for chronic wounds, and discuss major challenges that confront future clinical applications. We found that a wealth of animal studies have revealed the versatile roles and the benefits of MSCs for chronic wound healing. MSC treatment results in enhanced angiogenesis, facilitated reepithelialization, improved granulation, and accelerated wound closure. There are some evidences of the transdifferentiation of MSCs into skin cells. However, the healing effect of MSCs depends primarily on their paracrine actions, which alleviate the harsh microenvironment of chronic wounds and regulate local cellular responses. Consistent with the findings of preclinical studies, some clinical trials have shown improved wound healing after transplantation of MSCs in chronic wounds, mainly lower extremity ulcers, pressure sores, and radiation burns. However, there are some limitations in these clinical trials, especially a small number of patients and imperfect methodology. Therefore, to better define the safety and efficiency of MSC-based wound therapy, large-scale controlled multicenter trials are needed in the future. In addition, to build a robust pool of clinical evidence, standardized protocols, especially the cultivation and quality control of MSCs, are recommended. Altogether, based on current data, MSC-based therapy represents a promising treatment option for chronic wounds. Impact statement Chronic wounds persist as a significant health care problem, particularly with increasing number of patients and the lack of efficient treatments. The main goal of this article is to provide an overview of current status of mesenchymal stem cell (MSC)-based therapy for chronic wounds. The roles of MSCs in skin wound healing, as revealed in a large number of animal studies, are detailed. A critical view is made on the clinical application of MSCs for lower extremity ulcers, pressure sores, and radiation burns. Main challenges that confront future clinical applications are discussed, which hopefully contribute to innovations in MSC-based wound treatment.

Mesenchymal Stem Cells for Regenerative Medicine

In recent decades, the biomedical applications of mesenchymal stem cells (MSCs) have attracted increasing attention. MSCs are easily extracted from the bone marrow, fat, and synovium, and differentiate into various cell lineages according to the requirements of specific biomedical applications. As MSCs do not express significant histocompatibility complexes and immune stimulating molecules, they are not detected by immune surveillance and do not lead to graft rejection after transplantation. These properties make them competent biomedical candidates, especially in tissue engineering. We present a brief overview of MSC extraction methods and subsequent potential for differentiation, and a comprehensive overview of their preclinical and clinical applications in regenerative medicine, and discuss future challenges.

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 Healing Effects of Conditioned Medium Derived from Mesenchymal Stem Cells on Radiation-Induced Skin Wounds in Rats

Radioactive dermatitis is caused by the exposure of skin and mucous membranes to radiation fields. The pathogenesis of radioactive dermatitis is complex and difficult to cure. Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) may serve as a promising candidate for the therapy of cutaneous wounds. The aim of this study was to investigate whether a WJ-MSC-derived conditioned medium (MSC-CM) could be used to treat radiation-induced skin wounds in rats using a radiation-induced cutaneous injury model. The present study was designed to examine MSC-CM therapy in the recovery of radiation-induced skin wounds in vitro and in vivo. Firstly, we prepared the MSC-CM and tested the effects of the MSC-CM on human umbilical vein endothelial cell proliferation in vitro. After that, we used a β-ray beam to make skin wounds in rats and tested the effects of MSC-CM on cutaneous wound healing in vivo. Our results indicated that MSC-CM secreted factors that promoted HUVEC proliferation, regeneration of sebaceous glands, and angiogenesis. Importantly, MSC-CM promoted wound healing in excess of the positive control (epidermal growth factor), with no, or smaller, scar formation. In conclusion, MSC-CM significantly accelerated wound closure and enhanced the wound healing quality. MSC-CM has a beneficial therapeutic effect on radiation-induced cutaneous injury skin in rats and in this way MSC-CM may serve as a basis of a novel cell-free therapeutic approach for radiation dermatitis.

Electron spin resonance (ESR) dose measurement in bone of Hiroshima A-bomb victim

Explosion of the bombs in Hiroshima and Nagasaki corresponds to the only historical moment when atomic bombs were used against civilians. This event triggered countless investigations into the effects and dosimetry of ionizing radiation. However, none of the investigations has used the victims’ bones as dosimeter. Here, we assess samples of bones obtained from fatal victims of the explosion by Electron Spin Resonance (ESR). In 1973, one of the authors of the present study (SM) traveled to Japan and conducted a preliminary experiment on the victims’ bone samples. The idea was to use the paramagnetism induced in bone after irradiation to measure the radiation dose. Technological advances involved in the construction of spectrometers, better knowledge of the paramagnetic center, and improvement in signal processing techniques have allowed us to resume the investigation. We obtained a reconstructed dose of 9.46 ± 3.4 Gy from the jawbone, which was compatible with the dose distribution in different locations as measured in non-biological materials such as wall bricks and roof tiles.

The application of mesenchymal stem cells to treat thermal and radiation burns

Mesenchymal stem cells (MSCs) have been developed for a number of indications due to their regenerative and anti-inflammatory phenotypes and their utility is enhanced by the fact that allogeneic transplant is feasible with this cell type. Animal studies and early human cases indicate that this has the potential to be an exciting new therapy for treating chronic non-healing wounds such as diabetic ulcers, burns and cutaneous radiation burns. This review will focus on the use of MSCs to treat thermal and radiation burns. Large, severe burns are difficult to treat and pose a major public health burden worldwide. They are characterized by an extensive loss of the outer protective barrier, delayed wound healing, increased oxidative stress and a heightened inflammatory state. The breakdown of the protective barrier results in increased susceptibility to fluid loss and bacterial sepsis. In the case of radiation burns, chronic inflammation can result in subsequent waves of tissue injury leading to skin breakdown and necrosis. The aim of this review is to summarize the current knowledge on MSCs in treating thermal and radiation burns along with the specific scope of characterizing the biologic function of MSCs that help enhance wound healing in these chronic injuries.

In vitro differentiation of menstrual blood stem cells into keratinocytes: A potential approach for management of wound healing

The skin wounds caused by insults should be treated immediately to restore the functions and integrity. Recent studies suggest that stem cells-based therapies may be applicable in wound healing. Newly defined menstrual blood-derived stem cells (MenSCs) show high rate of cell proliferation and trans-differentiation potency to various cell types. However, MenSCs potential to generate keratinocyte for future therapeutic use of skin lesions has been remained to investigate. We cultivated MenSCs in the presence of isolated foreskin derived-keratinocytes using an indirect co-culture system and evaluated efficiency of this protocol to generate keratinocytes using immunofluorescent staining and Real Time PCR technique. Our results showed that differentiated keratinocytes express epidermal/keratinocytes lineage specific markers such as K14, p63, and involucrin at both mRNA and protein levels. Immunofluorescent staining showed the expression of involucrin and K14 in differentiated cells in contrast to undifferentiated cells. Moreover, mRNA expression levels of K14 (11.1 folds, p = 0.001), p63 (10.23 folds, p = 0.001), and involucrin (2.94 folds, p = 0.001) were higher in differentiated MenSCs compared to non-cocultured cells. Therefore, we firstly presented evidence about differentiation capability of MenSCs into epidermal/keratinocytes lineage. Considering the advantages of MenSCs such as great accessibility, these stem cells are promising for stem cells-based therapies of skin defects.