Stem-cell extracellular vesicles and lung repair

Stem cell therapies for chronic obstructive pulmonary disease: mesenchymal stem cells as a promising treatment option

Chronic obstructive pulmonary disease(COPD) is an inflammatory disease characterized by the progressive and irreversible structural and functional damage of lung tissue. Although COPD is a significant global disease burden, the available treatments only ameliorate the symptoms, but cannot reverse lung damage. Researchers in regenerative medicine have examined the use of stem cell transplantation for treatment of COPD and other diseases because these cells have the potential for unlimited self-renewal and the ability to undergo directed differentiation. Stem cells are typically classified as embryonic stem cells, induced pluripotent stem cells, and adult stem cells (which includes mesenchymal stem cells [MSCs]), each with its own advantages and disadvantages regarding applications in regenerative medicine. Although the heterogeneity and susceptibility to senescence of MSCs make them require careful consideration for clinical applications. However, the low tumourigenicity and minimal ethical concerns of MSCs make them appear to be excellent candidates. This review summarizes the characteristics of various stem cell types and describes their therapeutic potential in the treatment of COPD, with a particular emphasis on MSCs. We aim to facilitate subsequent in-depth research and preclinical applications of MSCs by providing a comprehensive overview.

The effect of acellular scaffold loaded with Wharton's jelly-derived stem cells and mineral pitch on healing of burn model in rat

Severe burns often result in an exacerbated inflammatory response, which can contribute to further injury. This inflammatory response may lead to an increased risk of infection, multiple organ failure, and death. This study aimed to investigate the potential of reducing inflammation to enhance burn wound healing in rats using ovine's small intestinal submucosa as a carrier for Wharton's jelly mesenchymal stem cells (WJ-MSCs) and Mineral Pitch (MP). A rat burn model was developed, and the animals were divided into four groups: control group: burn, placebo group: scaffold-treated burn, cell experimental group: WJ-MSCs seeded scaffold-treated burn, and cell and MP experimental group: scaffolds loaded with WJ-MSCs and MP-treated burn. After treating the wounds in the relevant groups and sampling them on days 5, 14 and 21, histological and pathological parameters, and the expression of genes involved in angiogenesis and epithelialization were evaluated. The study results revealed several findings in the burn wounds. These included changes in mast cell populations, a decrease in inflammatory neutrophils and lymphocytes, an increase in fibroblasts and blood vessels, and upregulation of angiogenesis and epithelialization genes. These changes collectively contributed to enhanced wound healing in cell and MP experimental group compared to the other groups. The findings suggest that scaffolds loaded with Wharton's jelly-derived stem cells and MP can serve as engineered tools to modulate inflammatory conditions during the burn wound healing process. These interventions can improve burn wound management and promote better outcomes.

Mesenchymal stem cells and their derived exosomes for the treatment of COVID-19

Coronavirus disease 2019 (COVID-19) is an acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 infection typically presents with fever and respiratory symptoms, which can progress to severe respiratory distress syndrome and multiple organ failure. In severe cases, these complications may even lead to death. One of the causes of COVID-19 deaths is the cytokine storm caused by an overactive immune response. Therefore, suppressing the overactive immune response may be an effective strategy for treating COVID-19. Mesenchymal stem cells (MSCs) and their derived exosomes (MSCs-Exo) have potent homing abilities, immunomodulatory functions, regenerative repair, and antifibrotic effects, promising an effective tool in treating COVID-19. In this paper, we review the main mechanisms and potential roles of MSCs and MSCs-Exo in treating COVID-19. We also summarize relevant recent clinical trials, including the source of cells, the dosage and the efficacy, and the clinical value and problems in this field, providing more theoretical references for the clinical use of MSCs and MSCs-Exo in the treatment of COVID-19.

Anti-inflammatory therapies for acute respiratory distress syndrome

INTRODUCTION

Treatments for the acute respiratory distress syndrome (ARDS) are mainly supportive, and ventilatory management represents a key approach in these patients. Despite progress in pharmacotherapy, anti-inflammatory strategies for the treatment of ARDS have shown controversial results. Positive outcomes with pharmacologic and nonpharmacologic treatments have been found in two different biological subphenotypes of ARDS, suggesting that, with a personalized medicine approach, pharmacotherapy for ARDS can be effective.

AREAS COVERED

This article reviews the literature concerning anti-inflammatory therapies for ARDS, focusing on pharmacological and stem-cell therapies, including extracellular vesicles.

EXPERT OPINION

Despite advances, ARDS treatments remain primarily supportive. Ventilatory and fluid management are important strategies in these patients that have demonstrated significant impacts on outcome. Anti-inflammatory drugs have shown some benefits, primarily in preclinical research and in specific clinical scenarios, but no recommendations are available from guidelines to support their use in patients with ARDS, except in particular settings such as different subphenotypes, specific etiologies, or clinical trials. Personalized medicine seems promising insofar as it may identify specific subgroups of patients with ARDS who may benefit from anti-inflammatory treatment. However, additional efforts are needed to move subphenotype characterization from bench to bedside.

Targeting extracellular vesicle delivery to the lungs by microgel encapsulation

Extracellular vesicles (EVs) secreted by stem and progenitor cells have significant potential as cell-free 'cellular' therapeutics. Yet, small EVs (<200 nm) are rapidly cleared after systemic administration, mainly by the liver, presenting challenges targeting EVs to a specific organ or tissue. Microencapsulation using natural nano-porous hydrogels (microgels) has been shown to enhance engraftment and increase the survival of transplanted cells. We sought to encapsulate EVs within microgels to target their delivery to the lung by virtue of their size-based retention within the pulmonary microcirculation. Mesenchymal stromal cell (MSC) derived EVs were labelled with the lipophilic dye (DiR) and encapsulated within agarose-gelatin microgels. Endothelial cells and bone marrow derived macrophages were able to take up EVs encapsulated in microgels in vitro, but less efficiently than the uptake of free EVs. Following intrajugular administration, microgel encapsulated EVs were selectively retained within the lungs for 72h, while free EVs were rapidly cleared by the liver. Furthermore, microgel-loaded EVs demonstrated greater uptake by lung cells, in particular CD45+ immune cells, as assessed by flow cytometry compared to free EVs. Microencapsulation of EVs may be a novel tool for enhancing the targeted delivery of EVs for future therapeutic applications.

The Effect of Fetal Bovine Acellular Dermal Matrix Seeded with Wharton's Jelly Mesenchymal Stem Cells for Healing Full-Thickness Skin Wounds

The treatment of full-thickness skin wounds is a problem in the clinical setting, as they do not heal spontaneously. Extensive pain at the donor site and a lack of skin grafts limit autogenic and allogeneic skin graft availability. We evaluated fetal bovine acellular dermal matrix (FADM) in combination with human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) to heal full-thickness skin wounds. FADM was prepared from a 6-month-old trauma-aborted fetus. WJ-MSCs were derived from a human umbilical cord and seeded on the FADM. Rat models of full-thickness wounds were created and divided into three groups: control (no treatment), FADM, and FADM-WJMSCs groups. Wound treatment was evaluated microscopically and histologically on days 7, 14, and 21 post-surgery. The prepared FADM was porous and decellularized with a normal range of residual DNA. WJ-MSCs were seeded and proliferated on FADM effectively. The highest wound closure rate was observed in the FADM-WJMSC group on days 7 and 14 post-surgery. Furthermore, this group had fewer inflammatory cells than other groups. Finally, in this study, we observed that, without using the differential cell culture media of fibroblasts, the xenogeneic hWJSCs in combination with FADM could promote an increased rate of full-thickness skin wound closure with less inflammation.

Effects of transplanted mesenchymal stem cells on repair of the lung tissue of rats with experimental pulmonary fibrosis

Pulmonary fibrosis is one of the commonest forms of interstitial lung diseases with poorly studied methods of its treatment in both human and veterinary medicines. Therefore, this paper focused on seeking alternative methods of its diagnostics and treatment. The article provides the results of the study of bronchoalveolar lavage fluid of rats with experimental lung fibrosis and influence of transplanted allogeneic mesenchymal stem cells of the bone marrow on stimulation of regenerative processes in damaged lung tissues. The studies were conducted on female Wistar rats with pulmonary fibrosis modeled using single transthoracic injection of solution of bleomycin hydrochloride. For the purpose of treatment, we used allogeneic mesenchymal stem cells introduced by various methods and the traditional treatment. We determined that best normalization of the parameters of the studied brochoalveolar lavage occurred in animals that received mesenchymal stem cells. The most active repair processes were in the experimental group that received the mesenchymal stem cells directly to the lung tissue. The animals that received intravenous injection of mesenchymal stemm cells were observed to have lower clinical parameters of the brochoalveolar lavage, but still better than such in the group treated traditionally. The lowest parameters were in animals that received the traditional treatment; they were greater than the phisological parameters, but significantly exceeded them in animals of the control group, indicating presence of inflammatory process in the lung tissue. The conducted cytological assays of the samples of the brochoalveolar lavage revealed that experimental animals with experimental pulmonary fibrosis had development of macrophage and lymphocytic reactions under the influence of transplanted mesenchymal stemm cells. We observed no atypical cells in all the experimental groups. This allows us to draw a conclusion that using stem cells by various methods of transplantation does not stimulate the onset of negative reactons (formation of atypical cells, metastatic processes, etc). Thus, the results of the study of the influence of transplanted mesenchymal stem cells demonstrate that in the conditions of experimental pulmonary fibrosis, the activity of regenerative processes in pathologically altered lung tissue may be an effective method of treatment of animals with this kind of pathology.

Human Umbilical Cord-Derived Mesenchymal Stem Cells Alleviate Acute Lung Injury Caused by Severe Burn via Secreting TSG-6 and Inhibiting Inflammatory Response

Objectives

To investigate whether hUC-MSCs attenuated severe burn-induced ALI and the effects were based on TSG-6 secreted from hUC-MSCs.

Method

A rat model was established and evaluated as follows: cytokine expression was measured by ELISA, and both inflammatory cell infiltration and lung injury were assessed by immunohistochemistry assay.

Results

In vitro, TSG-6 levels in serum from the burn group were significantly increased compared with those from the sham group. In vivo, TSG-6 levels of lung tissues and serum in the burn+hUC-MSC group were significantly increased compared with those in the burn group. Both in lung tissues and in serum, increased levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) were remarkably decreased, but the anti-inflammatory cytokine IL-10 increased after hUC-MSC administration (p < 0.05). These significant positive effects after hUC-MSC transplantation did not occur in the burn+siTSG-6 group.

Conclusion

The intratracheal implantation of hUC-MSCs has been an effective treatment for severe burn-induced ALI via promoting TSG-6 secretion and inhibiting inflammatory reaction in lung tissue.

Evaluation the ability of acellular ovine small intestine submucosa to load and release of mineral pitch and its anti-inflammatory effects

Injury from the severe burn is exacerbated by a persistent inflammatory response. This response is mediated by cytokines and chemokines, which are released from various immune cells, including mast cells. In this study, the ability of the acellular ovine small intestine submucosa (AOSIS) to load and release of Mineral Pitch (MP) was first investigated, and it was found that the preparation of the scaffold by a modified method enables it to load and release water-soluble drugs. Then, 32 male Wistar rats were divided into four groups, a third-degree burn was created, and except for the control group, the others were treated with: AOSIS, WJ-MSCs seeded AOSIS, or AOSIS loaded with WJ-MSCs and MP. Wound sampling on the 5th day after treatment showed that the number of intact and degranulated mast cells in the treatment groups was associated with a decrease compared to the control group. In the last group, this decrease was the largest (and statically significant (p < 0.05)). Also, by measuring the level of inflammatory factors in blood serum, it was found that in the treatment groups compared to the control group, IL-10 was associated with an increase, and TNF-α was associated with a decrease. The changes in inflammatory factors were more significant (p < 0.05) in the last group. So, our results indicate that AOSIS loaded with WJ-MSCs and MP could be used as an innovative tissue-engineered device to control inflammatory condition during burn wound healing.

A comprehensive review of COVID-19 biology, diagnostics, therapeutics, and disease impacting the central nervous system

The ongoing COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly transmissible disease. SARS-CoV-2 is estimated to have infected over 153 million people and to have caused over 3.2 million global deaths since its emergence in December 2019. SARS-CoV-2 is the seventh coronavirus known to infect humans, and like other coronaviruses, SARS-CoV-2 infection is characterized by a variety of symptoms including general flu-like symptoms such as a fever, sore throat, fatigue, and shortness of breath. Severe cases often display signs of pneumonia, lymphopenia, acute kidney injury, cardiac injury, cytokine storms, lung damage, acute respiratory distress syndrome (ARDS), multiple organ failure, sepsis, and death. There is evidence that around 30% of COVID-19 cases have central nervous system (CNS) or peripheral nervous system (PNS) symptoms along with or in the absence of the previously mentioned symptoms. In cases of CNS/PNS impairments, patients display dizziness, ataxia, seizure, nerve pain, and loss of taste and/or smell. This review highlights the neurological implications of SARS-CoV-2 and provides a comprehensive summary of the research done on SARS-CoV-2 pathology, diagnosis, therapeutics, and vaccines up to May 5.

Is there a place for mesenchymal stromal cell-based therapies in the therapeutic armamentarium against COVID-19?

The COVID-19 pandemic, caused by the rapid global spread of the novel coronavirus (SARS-CoV-2), has caused healthcare systems to collapse and led to hundreds of thousands of deaths. The clinical spectrum of COVID-19 is not only limited to local pneumonia but also represents multiple organ involvement, with potential for systemic complications. One year after the pandemic, pathophysiological knowledge has evolved, and many therapeutic advances have occurred, but mortality rates are still elevated in severe/critical COVID-19 cases. Mesenchymal stromal cells (MSCs) can exert immunomodulatory, antiviral, and pro-regenerative paracrine/endocrine actions and are therefore promising candidates for MSC-based therapies. In this review, we discuss the rationale for MSC-based therapies based on currently available preclinical and clinical evidence of safety, potential efficacy, and mechanisms of action. Finally, we present a critical analysis of the risks, limitations, challenges, and opportunities that place MSC-based products as a therapeutic strategy that may complement the current arsenal against COVID-19 and reduce the pandemic's unmet medical needs.

Exosomal miR-218-5p/miR-363-3p from Endothelial Progenitor Cells Ameliorate Myocardial Infarction by Targeting the p53/JMY Signaling Pathway

Accumulating evidence has shown that endothelial progenitor cell-derived exosomes (EPC-Exos) can ameliorate myocardial fibrosis. The purpose of the present study was to investigate the effects of EPC-Exos-derived microRNAs (miRNAs) on myocardial infarction (MI). A miRNA-Seq dataset of miRNAs differentially expressed between EPCs and exosomes was collected. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the miRNA expression indicated by miRNA-Seq. Immunofluorescence, cell proliferation, and angiogenesis assays were employed to investigate the effects of miRNAs on cardiac fibroblasts (CFs) in vitro. Interactions between miRNAs and their respective targets were examined via immunoblotting, qRT-PCR, and luciferase reporter assays. An MI rat model was constructed, and various staining and immunohistochemical assays were performed to explore the mechanisms underlying the miRNA-mediated effects on MI. miR-363-3p and miR-218-5p were enriched in EPC-Exos, and miR-218-5p and miR-363-3p mimic or inhibitor enhanced or suppressed CF proliferation and angiogenesis, respectively. miR-218-5p and miR-363-3p regulated p53 and junction-mediating and regulatory protein (JMY) by binding to the promoter region of p53 and the 3′ untranslated region of JMY. Additionally, treatment of CFs with Exo-miR-218-5p or Exo-miR-363-3p upregulated p53 and downregulated JMY expression, promoted mesenchymal-endothelial transition, and inhibited myocardial fibrosis. Administration of exosomes containing miR-218-5p mimic or miR-363-3p mimic ameliorated left coronary artery ligation-induced MI and restored myocardial tissue integrity in the MI model rats. In summary, these results show that the protective ability of EPC-Exos against MI was mediated by the shuttled miR-218-5p or miR-363-3p via targeting of the p53/JMY signaling pathway.

Dodging COVID-19 infection: low expression and localization of ACE2 and TMPRSS2 in multiple donor-derived lines of human umbilical cord-derived mesenchymal stem cells

Background

Mesenchymal stem cells derived from human umbilical cord (hUC-MSCs) have immunomodulatory properties that are of interest to treat novel coronavirus disease 2019 (COVID-19). Leng et al. recently reported that hUC-MSCs derived from one donor negatively expressed Angiotensin-Converting Enzyme 2 (ACE2), a key protein for viral infection along with Transmembrane Serine Protease 2 (TMPRSS2). The purpose of this study was to quantify the expression of ACE2 and TMPRSS2 in hUC-MSCs lots derived from multiple donors using molecular-based techniques in order to demonstrate their inability to be a host to SARS-CoV-2.

Methods

Expression of ACE2 and TMPRSS2 was analyzed in 24 lots of hUC-MSCs derived from Wharton's jelly via quantitative polymerase chain reaction (qPCR), Western Blot, immunofluorescence and flow cytometry using 24 different donors.

Results

hUC-MSCs had significantly lower ACE2 (p = 0.002) and TMPRSS2 (p = 0.008) expression compared with human lung tissue homogenates in Western blot analyses. Little to no expression of ACE2 was observed in hUC-MSC by qPCR, and they were not observable with immunofluorescence in hUC-MSCs cell membranes. A negative ACE2 and TMPRSS2 population percentage of 95.3% ± 15.55 was obtained for hUC-MSCs via flow cytometry, with only 4.6% ACE2 and 29.5% TMPRSS2 observable positive populations.

Conclusions

We have demonstrated negative expression of ACE2 and low expression of TMPRSS2 in 24 lots of hUC-MSCs. This has crucial implications for the design of future therapeutic options for COVID-19, since hUC-MSCs would have the ability to “dodge” viral infection to exert their immunomodulatory effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02813-6.

EVs from BALF-Mediators of Inflammation and Potential Biomarkers in Lung Diseases

Extracellular vesicles (EVs) have been identified as key messengers of intracellular communication in health and disease, including the lung. EVs that can be found in bronchoalveolar lavage fluid (BALF) are released by multiple cells of the airways including bronchial epithelial cells, endothelial cells, alveolar macrophages, and other immune cells, and they have been shown to mediate proinflammatory signals in many inflammatory lung diseases. They transfer complex molecular cargo, including proteins, cytokines, lipids, and nucleic acids such as microRNA, between structural cells such as pulmonary epithelial cells and innate immune cells such as alveolar macrophages, shaping mutually their functions and affecting the alveolar microenvironment homeostasis. Here, we discuss this distinct molecular cargo of BALF-EVs in the context of inducing and propagating inflammatory responses in particular acute and chronic lung disorders. We present different identified cellular interactions in the inflammatory lung via EVs and their role in lung pathogenesis. We also summarize the latest studies on the potential use of BALF-EVs as diagnostic and prognostic biomarkers of lung diseases, especially of lung cancer.

Pathophysiology of Lung Disease and Wound Repair in Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive, life-threatening condition affecting many organs and tissues, the lung disease being the chief cause of morbidity and mortality. Mutations affecting the CF Transmembrane Conductance Regulator (CFTR) gene determine the expression of a dysfunctional protein that, in turn, triggers a pathophysiological cascade, leading to airway epithelium injury and remodeling. In vitro and in vivo studies point to a dysregulated regeneration and wound repair in CF airways, to be traced back to epithelial CFTR lack/dysfunction. Subsequent altered ion/fluid fluxes and/or signaling result in reduced cell migration and proliferation. Furthermore, the epithelial-mesenchymal transition appears to be partially triggered in CF, contributing to wound closure alteration. Finally, we pose our attention to diverse approaches to tackle this defect, discussing the therapeutic role of protease inhibitors, CFTR modulators and mesenchymal stem cells. Although the pathophysiology of wound repair in CF has been disclosed in some mechanisms, further studies are warranted to understand the cellular and molecular events in more details and to better address therapeutic interventions.

Defining a Regulatory Strategy for ATMP/Aerosol Delivery Device Combinations in the Treatment of Respiratory Disease

Advanced Therapeutic Medicinal Products (ATMP) are a heterogenous group of investigational medicinal products at the forefront of innovative therapies with direct applicability in respiratory diseases. ATMPs include, but are not limited to, stem cells, their secretome, or extracellular vesicles, and each have shown some potential when delivered topically within the lung. This review focuses on that subset of ATMPs. One key mode of delivery that has enabling potential in ATMP validation is aerosol-mediated delivery. The selection of the most appropriate aerosol generator technology is influenced by several key factors, including formulation, patient type, patient intervention, and healthcare economics. The aerosol-mediated delivery of ATMPs has shown promise for the treatment of both chronic and acute respiratory disease in pre-clinical and clinical trials; however, in order for these ATMP device combinations to translate from the bench through to commercialization, they must meet the requirements set out by the various global regulatory bodies. In this review, we detail the potential for ATMP utility in the lungs and propose the nebulization of ATMPs as a viable route of administration in certain circumstances. Further, we provide insight to the current regulatory guidance for nascent ATMP device combination product development within the EU and US.

The Potential Use of Mesenchymal Stem Cells and Their Derived Exosomes as Immunomodulatory Agents for COVID-19 Patients

A novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) causing lethal acute respiratory disease emerged in December 2019. The World Health Organization named this disease "COVID-19" and declared it a pandemic on March 11, 2020. Many studies have shown that mesenchymal stem cells (MSCs) and their exosomes (MSCs-Exo), which are isolated from allogenic bone marrow stem cells, significantly lower the risk of alveolar inflammation and other pathological conditions associated with distinct lung injuries. For example, in acute respiratory distress syndrome (ARDS) and pneumonia patients, MSCs-Exo and MSCs provide similar healing properties and some clinical trials have used cell-based inhalation therapy which show great promise. MSCs and MSCs-Exo have shown potential in clinical trials as a therapeutic tool for severely affected COVID-19 patients when compared to other cell-based therapies, which may face challenges like the cells' sticking to the respiratory tract epithelia during administration. However, the use of MSCs or MSCs-Exo for treating COVID-19 should strictly adhere to the appropriate manufacturing practices, quality control measurements, preclinical safety and efficacy data, and the proper ethical regulations. This review highlights the available clinical trials that support the therapeutic potential of MSCs or MSCs-Exo in severely affected COVID-19 patients.

Adipose-derived mesenchymal stem cells ameliorate lung epithelial injury through mitigating of oxidative stress in mustard lung

Aim: We investigated potential efficacy of autologous adipose-derived mesenchymal stem cell (MSC) on oxidative stress (OS) and airway remodeling in patients with chronic mustard lung. Patients & methods: Ten patients received 100 × 106 cells every 20 days for 4 injections over a 2-month period. Results: A gradual improvement was observed for 6 min walk test scores, pulmonary function tests and respiratory quality after MSCs therapy. A significant decrease was found for the mean levels of Mucin-1 protein (KL-6; p = 0.022) and Clara cell protein 16 (CC16; p = 0.005). Antioxidants had a tendency to be higher after each injection. Conclusion: Our findings revealed that MSCs therapy can be safely used for improvement of lung injury and regeneration in these patients without adverse effects. Trial registration number: NCT02749448 (ClinicalTrials.gov).

Therapeutic Potential of “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling: Exosomes d-MAPPS” is Based on the Effects of Exosomes, Immunosuppressive and Trophic Factors

Due to their differentiation capacity and potent immunosuppressive and pro-angiogenic properties, mesenchymal stem cells (MSCs) have been considered as new therapeutic agents in regenerative medicine. Since most of MSC-mediated beneficent effects are a consequence of their paracrine action, we designed MSC-based product “Exosomes Derived Multiple Allogeneic Proteins Paracrine Signaling (Exosomes d-MAPPS), which activity is based on MSCs-derived growth factors and immunomodulatory cytokines capable to attenuate inflammation and to promote regeneration of injured tissues. Interleukin 1 receptor antagonist (IL-1Ra) and IL-27 were found in high concentrations in Exosomes d-MAPPS samples indicating strong anti-inflammatory and immunosuppressive potential of Exosomes d-MAPPS. Additionally, high concentrations of vascular endothelial growth factor receptor (VEGFR1) and chemokines (CXCL16, CCL21, CXCL14) were noticed at Exosomes d-MAPPS samples suggesting their potential to promote generation of new blood vessels and migration of CXCR6, CCR7 and CXCR4 expressing cells. Since all proteins which were found in high concentration in Exosomes d-MAPPS samples (IL-1Ra, CXCL16, CXCL14, CCL21, IL-27 and VEGFR1) are involved in modulation of lung, eye, and synovial inflammation, Exosomes d-MAPPS samples were prepared as inhalation and ophthalmic solutions in addition to injection formulations; their application in several patients suffering from chronic obstructive pulmonary disease, osteoarthritis, and dry eye syndrome resulted with significant improvement of biochemical and functional parameters. In conclusion, Exosomes d-MAPPS, due to the presence of important anti-inflammatory, immunomodulatory, and pro-angiogenic factors, represents potentially new therapeutic agent in regenerative medicine that should be further tested in large clinical studies.

The potential of mesenchymal stem cell therapy for chronic lung disease

Introduction: Mesenchymal stem/stromal cells (MSCs) have been shown to improve lung function and survival in chronic inflammatory lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), pulmonary arterial hypertension (PAH), and silicosis.Areas covered: This review covers rationale for the use of MSC therapy, along with preclinical studies and clinical trials with MSC therapy in chronic lung diseases.Expert opinion: MSC therapy holds promise for the treatment of chronic lung diseases, mainly when administered at early stages. In clinical trials, MSC administration was safe, but associated with limited effects on clinical outcomes. Further studies are required to elucidate unresolved issues, including optimal MSC source and dose, route of administration, and frequency (single vs. multiple-dose regimens). A better understanding of the mechanisms of MSC action, local microenvironment of each disease, and development of strategies to potentiate the beneficial effects of MSCs may improve outcomes.

The effect of allogenic human Wharton's jelly stem cells seeded onto acellular dermal matrix in healing of rat burn wounds

BACKGROUND

Various methods were introduced to overcome the autograft shortage in burn wound care, including cell transplantation and tissue engineering.

AIMS

To evaluate the healing effect of allogenic human Wharton's jelly stem cells (hWJSCs) seeded onto acellular dermal matrix (ADM) in rat burn injuries.

PATIENTS AND METHODS

Human Wharton's jelly stem cells provided from umbilical cord tissue were characterized before transplantation, and the growth kinetic was determined. Skin samples from cosmetic surgeries were used for preparation of ADM. Forty male Sprague Dawley rats were randomly divided into 4 equal groups. Third-degree burn was induced for all animals by exposing to hot water using a 2 cm ring for 10 seconds. Group 1 was burned rats that did not receive any treatment. After burn injury, the second group received silver sulfadiazine (SSD), the third group was treated just by using ADM, and the fourth group received 2 × 10⁶ hWJSCs seeded onto ADM. The animals were euthanized for histologic evaluation after 7, 14, and 21 days.

RESULTS

Human Wharton's jelly stem cells were characterized to be spindle shape and positive for osteogenic and adipogenic induction and for mesenchymal markers but lacked hematopoietic markers. Population doubling time (PDT) was 40.1 hours with an increasing growth trend until day 6th. Macro- and microscopically, the healing was mild in ADM group and moderate in ADM + hWJSCs group after 21 days.

CONCLUSION

Allogenic hWJSCs seeded onto ADM improved the healing process in burn wounds denoting to their therapeutic and anti-inflammatory effects in burn wounds that can be added to the literature.

Mesenchymal stem cell-derived extracellular vesicles improve the molecular phenotype of isolated rat lungs during ischemia/reperfusion injury

BACKGROUND

Lung ischemia/reperfusion (IR) injury contributes to the development of severe complications in patients undergoing transplantation. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) exert beneficial actions comparable to those of MSCs without the risks of the cell-based strategy. This research investigated EV effects during IR injury in isolated rat lungs.

METHODS

An established model of 180-minutes ex vivo lung perfusion (EVLP) was used. At 60 minutes EVs (n = 5) or saline (n = 5) were administered. Parallel experiments used labeled EVs to determine EV biodistribution (n = 4). Perfusate samples were collected to perform gas analysis and to assess the concentration of nitric oxide (NO), hyaluronan (HA), inflammatory mediators, and leukocytes. Lung biopsies were taken at 180 minutes to evaluate HA, adenosine triphosphate (ATP), gene expression, and histology.

RESULTS

Compared with untreated lungs, EV-treated organs showed decreased vascular resistance and a rise of perfusate NO metabolites. EVs prevented the reduction in pulmonary ATP caused by IR. Increased medium-high-molecular-weight HA was detected in the perfusate and in the lung tissue of the IR + EV group. Significant differences in cell count on perfusate and tissue samples, together with induction of transcription and synthesis of chemokines, suggested EV-dependent modulation of leukocyte recruitment. EVs upregulated genes involved in the resolution of inflammation and oxidative stress. Biodistribution analysis showed that EVs were retained in the lung tissue and internalized within pulmonary cells.

CONCLUSIONS

This study shows multiple novel EV influences on pulmonary energetics, tissue integrity, and gene expression during IR. The use of cell-free therapies during EVLP could constitute a valuable strategy for reconditioning and repair of injured lungs before transplantation.

Immunoregulatory role of exosomes derived from differentiating mesenchymal stromal cells on inflammation and osteogenesis

Bone marrow-derived mesenchymal stem/stromal cells (BMSCs) can differentiate into bone-forming osteoblasts, playing a crucial role in bone regeneration. Exosomes are naturally cell-secreted nanovesicles and are lately regraded as an emerging mediator of cellular communication in physiological and pathological conditions. The present study aimed at investigating the complex cellular communications, especially those among the differentiating BMSCs, immune cells (e.g., macrophages), and newly recruited BMSCs via exosome-mediated pathways. Exosomes were first isolated from osteogenically differentiating BMSCs at various stages (Day 0, Day 3, Day 7, and Day 14, respectively). The cellular uptake of isolated exosomes was examined in macrophages and human BMSCs (hBMSCs). The exosomes collected at various osteogenic differentiation stages (0d-exo, 3d-exo, 7d-exo, and 14d-exo) had no effect on the viability of hBMSCs. The uptake of exosomes (0d-exo, 3d-exo, and 7d-exo) significantly decreased proinflammatory-gene expression and the level of an M1 phenotypic marker. Our results then revealed that 3d-exo, 7d-exo, and 14d-exo led to a remarkable increase in mesenchymal stem/stromal cell migration. In addition, 0d-exo significantly promoted the expression of early osteogenic markers, such as alkaline phosphatase and bone morphogenetic protein 2, indicating a pro-osteogenic role of hBMSC-derived exosomes. Collectively, these results suggest that exosomes derived from differentiating mesenchymal stem/stromal cells play a unique osteoimmunomodulatory role in the regulation of bone dynamics.

Mesenchymal stem cells for inflammatory airway disorders: promises and challenges

The regenerative and immunomodulatory characteristics of mesenchymal stem cells (MSCs) make them attractive in the treatment of many diseases. Although they have shown promising preclinical studies of immunomodulation and paracrine effects in inflammatory airway disorders and other lung diseases, there are still challenges that have to be overcome before MSCs can be safely, effectively, and routinely applied in the clinical setting. A good understanding of the roles and mechanisms of the MSC immunomodulatory effects will benefit the application of MSC-based clinical therapy. In this review, we summarize the promises and challenges of the preclinical and clinical trials of MSC therapies, aiming to better understand the role that MSCs play in attempt to treat inflammatory airway disorders.

EphA2-positive human umbilical cord-derived mesenchymal stem cells exert anti-fibrosis and immunomodulatory activities via secretion of prostaglandin E2

OBJECTIVE

Previous study has demonstrated that EphA2 is a biomarker of mesenchymal stem cells (MSCs) from human placenta or umbilical cord and is able to distinguish MSCs from fibroblasts. In this study, we further examine the potential efficacy of EphA2⁺ human umbilical cord-derived MSCs (hUC-MSCs).

MATERIALS AND METHODS

MSCs specific markers, EphA2 and CD146 expression on the surface of hUC-MSCs were determined by flow cytometry analysis. Quantitative real time polymerase chain reaction was used to examine pro-fibrotic gene expression of TGF-β1-stimulated lung fibroblast (MRC-5 cells). On the other hand, ELISA was used to analyze the content of pro-inflammatory cytokines (TNF-ɑ; and IP-10) in the LPS-activated macrophages culture supernatant.

RESULTS

The pro-fibrotic gene (TGF-β1, CTGF, fibronectin, collagen I and TIMP-1) expression in TGF-β1-activated MRC-5 cells and the pro-inflammatory cytokines (TNF-ɑ and IP-10) in the LPS-activated macrophages culture supernatant were both attenuated when in present of EphA2⁺ hUC-MSCs. Moreover, once EphA2⁺ hUC-MSCs treated with prostaglandin E2 specific inhibitor NS-398, both anti-fibrotic and anti-inflammatory effects of EphA2⁺ hUC-MSCs were abolished.

CONCLUSION

EphA2⁺ hUC-MSCs possess immunomodulatory and anti-fibrotic properties, and PGE2 plays an important role in these activities. This implies that EphA2⁺ hUC-MSCs have potentially effectiveness for treatment of acute inflammatory and chronic fibrotic lung diseases.

Clinical Application of Mesenchymal Stem Cell-Derived Extracellular Vesicle-Based Therapeutics for Inflammatory Lung Diseases

It is currently thought that extracellular vesicles (EVs), such as exosomes and microvesicles, play an important autocrine/paracrine role in intercellular communication. EVs package proteins, mRNA and microRNA (miRNA), which have the ability to transfer biological information to recipient cells in the lungs. Depending on their origin, EVs fulfil different functions. EVs derived from mesenchymal stem cells (MSCs) have been found to promote therapeutic activities that are comparable to MSCs themselves. Recent animal model-based studies suggest that MSC-derived EVs have significant potential as a novel alternative to whole-cell therapies. Compared to their parent cells, EVs may have a superior safety profile and can be stored without losing function. It has been observed that MSC-derived EVs suppress pro-inflammatory processes and reduce oxidative stress, pulmonary fibrosis and remodeling in a variety of in vivo inflammatory lung disease models by transferring their components. However, there remain significant challenges to translate this therapy to the clinic. From this view point, we will summarize recent studies on EVs produced by MSCs in preclinical experimental models of inflammatory lung diseases. We will also discuss the most relevant issues in bringing MSC-derived EV-based therapeutics to the clinic for the treatment of inflammatory lung diseases.

Extracellular vesicles, exosomes and shedding vesicles in regenerative medicine - a new paradigm for tissue repair

Tissue regeneration by stem cells is driven by the paracrine activity of shedding vesicles and exosomes, which deliver specific cargoes to the recipient cells. Proteins, RNA, cytokines and subsequent gene expression, orchestrate the regeneration process by improving the microenvironment to promote cell survival, controlling inflammation, repairing injury and enhancing the healing process. The action of microRNA is widely accepted as an essential driver of the regenerative process through its impact on multiple downstream biological pathways, and its ability to regulate the host immune response. Here, we present an overview of the recent potential uses of exosomes for regenerative medicine and tissue engineering. We also highlight the differences in composition between shedding vesicles and exosomes that depend on the various types of stem cells from which they are derived. The conditions that affect the production of exosomes in different cell types are deliberated. This review also presents the current status of candidate exosomal microRNAs for potential therapeutic use in regenerative medicine, and in applications involving widely studied organs and tissues such as heart, lung, cartilage and bone.

Protective Effects of Endothelial Progenitor Cell-Derived Extracellular Mitochondria in Brain Endothelium

Endothelial progenitor cells (EPCs) have been pursued as a potential cellular therapy for stroke and central nervous system injury. However, their underlying mechanisms remain to be fully defined. Recent experimental studies suggest that mitochondria may be released and transferred between cells. In this proof-of-concept study, we asked whether beneficial effects of EPCs may partly involve a mitochondrial phenomenon as well. First, EPC-derived conditioned medium was collected and divided into supernatant and particle fractions after centrifugation. Electron microscopy, Western blots, and flow cytometry showed that EPCs were able to release mitochondria. ATP and oxygen consumption assays suggested that these extracellular mitochondria may still be functionally viable. Confocal microscopy confirmed that EPC-derived extracellular mitochondria can be incorporated into normal brain endothelial cells. Adding EPC particles to brain endothelial cells promoted angiogenesis and decreased the permeability of brain endothelial cells. Next, we asked whether EPC-derived mitochondria may be protective. As expected, oxygen-glucose deprivation (OGD) increased brain endothelial permeability. Adding EPC-derived mitochondria particles to the damaged brain endothelium increased levels of mitochondrial protein TOM40, mitochondrial DNA copy number, and intracellular ATP. Along with these indirect markers of mitochondrial transfer, endothelial tightness was also restored after OGD. Taken together, these findings suggest that EPCs may support brain endothelial energetics, barrier integrity, and angiogenic function partly through extracellular mitochondrial transfer. Stem Cells 2018;36:1404-1410.

Effect of Different Preconditioning Regimens on the Expression Profile of Murine Adipose-Derived Stromal/Stem Cells

Stem cell-based therapies require cells with a maximum regenerative capacity in order to support regeneration after tissue injury and organ failure. Optimization of this regenerative potential of mesenchymal stromal/stem cells (MSC) or their conditioned medium by in vitro preconditioning regimens are considered to be a promising strategy to improve the release of regenerative factors. In the present study, MSC were isolated from inguinal adipose tissue (mASC) from C57BL/6 mice, cultured, and characterized. Then, mASC were either preconditioned by incubation in a hypoxic environment (0.5% O₂), or in normoxia in the presence of murine epidermal growth factor (EGF) or tumor necrosis factor α (TNFα) for 48 h. Protein expression was measured by a commercially available array. Selected factors were verified by PCR analysis. The expression of 83 out of 308 proteins (26.9%) assayed was found to be increased after preconditioning with TNFα, whereas the expression of 61 (19.8%) and 70 (22.7%) proteins was increased after incubation with EGF or in hypoxia, respectively. Furthermore, we showed the proliferation-promoting effects of the preconditioned culture supernatants on injured epithelial cells in vitro. Our findings indicate that each preconditioning regimen tested induced an individual expression profile with a wide variety of factors, including several growth factors and cytokines, and therefore may enhance the regenerative potential of mASC for cell-based therapies.

Secretome within the bone marrow microenvironment: A basis for mesenchymal stem cell treatment and role in cancer dormancy

The secretome produced by cells within the bone marrow is significant to homeostasis. The bone marrow, a well-studied organ, has multiple niches with distinct roles for supporting stem cell functions. Thus, an understanding of mediators involved in the regulation of stem cells could serve as a model for clinical problems and solutions such as tissue repair and regeneration. The exosome secretome of bone marrow stem cells is a developing area of research with respect to the regenerative potential by bone marrow cell, particularly the mesenchymal stem cells. The bone marrow niche regulates endogenous processes such as hematopoiesis but could also support the survival of tumors such as facilitating the cancer stem cells to exist in dormancy for decades. The bone marrow-derived secretome will be critical to future development of therapeutic strategies for oncologic diseases, in addition to regenerative medicine. This article discusses the importance for parallel studies to determine how the same secretome may compromise safety during the use of stem cells in regenerative medicine.

Cellular therapies and stem cell applications in trauma

BACKGROUND

As the leading cause of mortality in the United States, trauma management have improved drastically over the past few decades with improved resuscitation and hemorrhage control. Stem cells are being used in an attempt to augment healing from trauma.

DATA SOURCES

PubMed and ClinicalTrials.gov were searched for published and registered pre-clinical and clinical trials for the application of stem cells to AKI, ARDS, shock, infection, TBI, wound healing, and bone healing.

CONCLUSIONS

Stem cell therapy for augmentation of healing traumatic injuries appears safe, as demonstrated by completed phase I/II trials. Further large scale studies are needed to assess the clinical efficacy.