State of the Art Review of Cell Therapy in the Treatment of Lung Disease, and the Potential for Aerosol Delivery

From mesenchymal stem cells to their extracellular vesicles: Progress and prospects for asthma therapy

Asthma is a widespread public health concern, with an increasing incidence. Despite the implementation of current treatment strategies, asthma control, particularly for severe cases, remains suboptimal. Recent research has revealed the encouraging prospects of extracellular vesicles (EVs) secreted by mesenchymal stem cells (MSCs) as a viable therapeutic option for alleviating asthma symptoms. Therefore, the present review aims to provide an overview of the current progress and the therapeutic mechanisms of using MSC-derived EVs (MSC-EVs) for asthma treatment. Additionally, different administration approaches for EVs and their impacts on biodistribution and the curative outcomes of EVs are summarized. Notably, the potential benefits of nebulized inhalation of MSC-EVs are addressed. Also, the possibilities and challenges of using MSC-EVs for asthma treatment in clinics are highlighted. Overall, this review is intended to give new insight into the utilization of MSC-EVs as a potential biological drug for asthma treatment.

Cell spray printing combined with Lycium barbarum glycopeptide promotes repair of corneal epithelial injury

The corneal epithelium, located as the outermost layer of the cornea, is inherently susceptible to injuries that may lead to corneal opacities and compromise visual acuity. Rapid restoration of corneal epithelial injury is crucial for maintaining the transparency and integrity of the cornea. Cell spray treatment emerges as an innovative and effective approach in the field of regenerative medicine. In our study, a cell spray printing platform was established, and the optimal printing parameters were determined to be a printing air pressure of 5 PSI (34.47 kPa) and a liquid flow rate of 30 ml/h. Under these conditions, the viability and phenotype of spray-printed corneal epithelial cells were preserved. Moreover, Lycium barbarum glycopeptide (LBGP), a glycoprotein purified from wolfberry, enhanced proliferation while simultaneously inhibiting apoptosis of the spray-printed corneal epithelial cells. We found that the combination of cell spray printing and LBGP facilitated the rapid construction of multilayered cell sheets on flat and curved collagen membranes in vitro. Furthermore, the combined cell spray printing and LBGP accelerated the recovery of the rat corneal epithelium in the mechanical injury model. Our findings offer a therapeutic avenue for addressing corneal epithelial injuries and regeneration.

The safety and potential efficacy of exosomes overexpressing CD24 (EXO-CD24) in mild-moderate COVID-19 related ARDS

INTRODUCTION

EXO-CD24 are exosomes genetically manipulated to over-express Cluster of Differentiation (CD) 24. It consists of two breakthrough technologies: CD24, the drug, as a novel immunomodulator that is smarter than steroids without any side effects, and exosomes as the ideal natural drug carrier.

METHODS

A randomized, single blind, dose-finding phase IIb trial in hospitalized patients with mild to moderate Coronavirus disease 2019 (COVID-19) related Acute Respiratory Distress Syndrome (ARDS) was carried out in two medical centers in Athens. Patients received either 109 or 1010 exosome particles of EXO-CD24, daily, for five consecutive days and monitored for 28 days. Efficacy was assessed at day 7 among 91 patients who underwent randomization. The outcome was also compared in a post-hoc analysis with an income control group (n = 202) that fit the inclusion and exclusion criteria.

RESULTS

The mean age was 49.4 (± 13.2) years and 74.4% were male. By day 7, 83.7% showed improved respiratory signs and 64% had better oxygen saturation (SpO2) (p < 0.05). There were significant reductions in all inflammatory markers, most notably in C-reactive protein (CRP), lactate dehydrogenase (LDH), ferritin, fibrinogen and an array of cytokines. Conversely, levels of the anti-inflammatory cytokine Interleukin-10 (IL-10) were increased (p < 0.05). Of all the documented adverse events, none were considered treatment related. No drug-drug interactions were noted. Two patients succumbed to COVID-19. Post-hoc analysis revealed that EXO-CD24 patients exhibited greater improvements in clinical and laboratory outcomes compared to an observational income control group.

CONCLUSIONS

EXO-CD24 presents a promising therapeutic approach for hyper-inflammatory state and in particular ARDS. Its unique combination of exosomes, as a drug carrier, and CD24, as an immunomodulator, coupled with inhalation administration, warrants further investigation in a larger, international, randomized, quadri-blind trial against a placebo.

Clinical Trials of Mesenchymal Stem Cells for the Treatment of COVID 19

Mesenchymal Stem Cells (MSCs) are being investigated as a treatment for a novel viral disease owing to their immunomodulatory, anti-inflammatory, tissue repair and regeneration characteristics, however, the exact processes are unknown. MSC therapy was found to be effective in lowering immune system overactivation and increasing endogenous healing after SARS-CoV-2 infection by improving the pulmonary microenvironment. Many studies on mesenchymal stem cells have been undertaken concurrently, and we may help speed up the effectiveness of these studies by collecting and statistically analyzing data from them. Based on clinical trial information found on clinicaltrials. gov and on 16 November 2020, which includes 63 clinical trials in the field of patient treatment with COVID-19 using MSCs, according to the trend of increasing studies in this field, and with the help of meta-analysis studies, it is possible to hope that the promise of MSCs will one day be realized. The potential therapeutic applications of MSCs for COVID-19 are investigated in this study.

Inhaled CD24-Enriched Exosomes (EXO-CD24) as a Novel Immune Modulator in Respiratory Disease

Acute Respiratory Distress Syndrome (ARDS) is a major health concern with urgent unmet need for treatment options. There are three million new ARDS cases annually, and the disease's mortality rate is high (35-46%). Cluster of differentiation 24 (CD24), a long-known protein with multifaceted functions, is a small, heavily glycosylated, membrane-anchored protein which functions as an immune checkpoint control. CD24 allows for immune discrimination between Damage-Associated Molecular Patterns and Pathogen-Associated Molecular Patterns derived from pathogens. Exosomes are intraluminal vesicles which play an important role in intercellular communication. Exosomes offer the advantage of targeted delivery, which improves safety and efficacy. The safety and efficacy of EXO-CD24 is promising, as was shown in >180 ARDS patients in phase 1b/2a, phase 2b, and compassionate use. CD24 binds Damage-associated molecular patterns (DAMPs) and inhibits the activation of the NF-ĸB pathway, a pivotal mediator of inflammatory responses. In contrast to anti-inflammatory therapies that are cytokine-specific or steroids that shut down the entire immune system, EXO-CD24 acts upstream, reverting the immune system back to normal activity. Herein, the safety and efficacy of mEXO-CD24 is shown in murine models of several pulmonary diseases (sepsis, allergic asthma, Chronic Obstructive Pulmonary Disease(COPD), fibrosis). EXO CD24 can suppress the hyperinflammatory response in the lungs in several pulmonary diseases with a significant unmet need for treatment options.

The wonders of stem cells therapeutic application towards chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a respiratory condition characterized by its heterogeneous nature, progressive course, and significant impact on individuals' quality of life. It is a prevalent global health issue affecting a substantial number of individuals and can pose life-threatening complications if left unmanaged. The development and course of COPD can be influenced by a range of risk factors, including genetic predisposition and environmental exposures. Nevertheless, as researchers adopt a more comprehensive and expansive viewpoint of therapeutic techniques, the associated obstacles become more apparent. Indeed, a definitive medication for COPD that reliably leads to symptom alleviation has not yet been discovered. Therefore, the limitations of conventional therapy methods prompted researchers to focus on the advancement of novel procedures, potentially leading to significant outcomes. In contemporary times, the field of regenerative medicine and cell therapy has presented unprecedented opportunities for the exploration of innovative treatments for COPD, owing to the distinctive attributes exhibited by stem cells. Hence, it is imperative to provide due consideration to preclinical investigations and notable characteristics of stem cells as they serve as a means to comprehensively comprehend the fundamental mechanisms of COPD and uncover novel therapeutic strategies with enhanced efficacy for patients.

Inhaled Exosomes Genetically Manipulated to Overexpress CD24 (EXO-CD24) as a Compassionate Use in Severe ARDS Patients

RATIONALE

Acute respiratory distress syndrome (ARDS) is a major global health concern with a significant unmet need. EXO-CD24 is delivered via inhalation-reduced cytokines and chemokine secretion and lung injury in ARDS and improved survival in mice models of ARDS, influenza, and sepsis.

OBJECTIVES

This clinical paper aims to evaluate the potential of EXO-CD24, a novel immunomodulatory treatment, in the compassionate care of critically ill, intubated patients with post-infection-induced acute respiratory distress syndrome (ARDS).

METHODS

Eleven critically ill patients diagnosed with post-infection ARDS (10 with COVID-19 and one with an adenovirus-associated infection) were administered EXO-CD24 in four medical centers across Israel. The patients had multiple co-morbidities, including cancer, hypertension, diabetes, and ischemic heart disease, and met the criteria for severe ARDS according to the Berlin classification. EXO-CD24 was administered via inhalation, and adverse events related to its use were carefully monitored.

MEASUREMENTS AND MAIN RESULTS

The administration of EXO-CD24 did not result in any recorded adverse events. The median hospitalization duration was 11.5 days, and the overall mortality rate was 36%. Notably, patients treated at the Tel Aviv Medical Center (TASMC) showed a lower mortality rate of 12.5%. The WBC and CRP levels decreased in comparison to baseline levels at hospitalization, and rapid responses occurred even in patients with kidney transplants who were off the ventilator within a few days and discharged shortly thereafter. The production of cytokines and chemokines was significantly suppressed in all patients, including those who died. Among the patients at TASMC, four had kidney transplants and were on immunosuppressive drugs, and all of them fully recovered and were discharged from the hospital.

CONCLUSIONS

EXO-CD24 holds promise as a potential therapeutic agent for all stages of ARDS, even in severe intubated cases. Importantly, EXO-CD24 demonstrated a favorable safety profile without any apparent side effects with promising efficacy. Furthermore, the potential of EXO-CD24 as a platform for addressing hyper-inflammatory states warrants exploration. Further research and larger-scale clinical trials are warranted to validate these preliminary findings.

Safety and efficacy of mesenchymal stem cells in COVID-19 patients: A systematic review and meta-analysis

BACKGROUND

Coronavirus disease-19 (COVID-19) is a zoonotic disease that has become a global pandemic. The fast evolution of the COVID-19 pandemic and persist problems make COVID-19 highly infectious; publicly accessible literature and other sources of information continue to expand in volume. The mesenchymal stem cells (MSCs) therapy efficacy for COVID-19 is debatable.

OBJECTIVE

This systematic review and meta-analysis (SRMA) aimed to evaluate the usefulness of MSCs in treating COVID-19.

METHODS

Relevant publications were retrieved from databases up to April 30, 2022. In the case of dichotomous data, the 95% confidence intervals (CIs) and pooled risk ratio (RR) were estimated with a random effects model (REM) or fixed effects model (FEM). The pooled mean difference (MD) and 95% CIs were calculated with REM or FEM in continuous data. In the outcomes, studies with insufficient or unusable data were reported descriptively.

RESULTS

A total of eight randomized controlled trials (RCTs) with 464 people were chosen for this SRMA. Relative to the control group, mortality was significantly lower in the MSCs group (RR: 0.66, 95% CI: 0.44, 0.99, Z = 2.01, p = .04); other secondary outcomes, such as the clinical symptom improvement rate improved in the MSCs group (RR: 1.44, 95% CI: 1.05, 1.99, Z = 2.24, p = .03), clinical symptom improvement time (MD: -4.01, 95% CI: -6.33, -1.68, Z = 3.38, p = .0007), C-reactive protein (CRP) (MD: -39.16, 95% CI: -44.39, -33.94, Z = 14.70, p < .00001) and days to hospital discharge (MD: -3.83, 95% CI: -6.19, -1.48, Z = 3.19, p = .001) reduced significantly in MSCs group. However, the adverse reaction incidence did not change significantly.

CONCLUSIONS

MSCs are a viable therapy option for COVID-19 because of their safety and potential efficacy. With no significant adverse effects, MSCs can reduce mortality, clinical symptom improvement time, and days to hospital discharge, improve clinical symptoms, and reduce inflammatory cytokines CRP in COVID-19. However, further high-quality clinical studies are required to confirm these results.

Aerosol pulmonary immune engineering

Aerosolization of immunotherapies poses incredible potential for manipulating the local mucosal-specific microenvironment, engaging specialized pulmonary cellular defenders, and accessing mucosal associated lymphoid tissue to redirect systemic adaptive and memory responses. In this review, we breakdown key inhalable immunoengineering strategies for chronic, genetic, and infection-based inflammatory pulmonary disorders, encompassing the historic use of immunomodulatory agents, the transition to biological inspired or derived treatments, and novel approaches of complexing these materials into drug delivery vehicles for enhanced release outcomes. Alongside a brief description of key immune targets, fundamentals of aerosol drug delivery, and preclinical pulmonary models for immune response, we survey recent advances of inhaled immunotherapy platforms, ranging from small molecules and biologics to particulates and cell therapies, as well as prophylactic vaccines. In each section, we address the formulation design constraints for aerosol delivery as well as advantages for each platform in driving desirable immune modifications. Finally, prospects of clinical translation and outlook for inhaled immune engineering are discussed.

Special Issue "The Role of Mesenchymal Stem Cells on Inflammatory and Fibrotic Diseases"

This Special Issue focused on the complex role played by MSCs in the onset and development of inflammatory diseases: MSCs can support or counteract inflammation and, in turn, the onset of disease [...].

Not all nebulizers are created equal: Considerations in choosing a nebulizer for aerosol delivery during mechanical ventilation

INTRODUCTION

Aerosol therapy is commonly prescribed in the mechanically ventilated patient. Jet nebulizers (JN) and vibrating mesh nebulizers (VMN) are the most common nebulizer types, however, despite VMN's well established superior performance, JN use remains the most commonly used of the two. In this review, we describe the key differentiators between nebulizer types and how considered selection of nebulizer type may enable successful therapy and the optimization of drug/device combination products.

AREAS COVERED

Following a review of the published literature up to February 2023, the current state of the art in relation to JN and VMN is discussed under the headings of in vitro performance of nebulizers during mechanical ventilation, respective compatibility with formulations for inhalation, clinical trials making use of VMN during mechanical ventilation, distribution of nebulized aerosol throughout the lung, measuring the respective performance of nebulizers in the patient and non-drug delivery considerations in nebulizer choice.

EXPERT OPINION

Whether for standard care, or the development of drug/device combination products, the choice of nebulizer type should not be made without consideration of the unique needs of the combination of each of drug, disease and patient types, as well as target site for deposition, and healthcare professional and patient safety.

Imaging drug delivery to the lungs: Methods and applications in oncology

Direct delivery to the lung via inhalation is arguably one of the most logical approaches to treat lung cancer using drugs. However, despite significant efforts and investment in this area, this strategy has not progressed in clinical trials. Imaging drug delivery is a powerful tool to understand and develop novel drug delivery strategies. In this review we focus on imaging studies of drug delivery by the inhalation route, to provide a broad overview of the field to date and attempt to better understand the complexities of this route of administration and the significant barriers that it faces, as well as its advantages. We start with a discussion of the specific challenges for drug delivery to the lung via inhalation. We focus on the barriers that have prevented progress of this approach in oncology, as well as the most recent developments in this area. This is followed by a comprehensive overview of the different imaging modalities that are relevant to lung drug delivery, including nuclear imaging, X-ray imaging, magnetic resonance imaging, optical imaging and mass spectrometry imaging. For each of these modalities, examples from the literature where these techniques have been explored are provided. Finally the different applications of these technologies in oncology are discussed, focusing separately on small molecules and nanomedicines. We hope that this comprehensive review will be informative to the field and will guide the future preclinical and clinical development of this promising drug delivery strategy to maximise its therapeutic potential.

Application of Precision-Cut Lung Slices as an In Vitro Model for Research of Inflammatory Respiratory Diseases

The leading cause of many respiratory diseases is an ongoing and progressive inflammatory response. Traditionally, inflammatory lung diseases were studied primarily through animal models, cell cultures, and organoids. These technologies have certain limitations, despite their great contributions to the study of respiratory diseases. Precision-cut lung slices (PCLS) are thin, uniform tissue slices made from human or animal lung tissue and are widely used extensively both nationally and internationally as an in vitro organotypic model. Human lung slices bridge the gap between in vivo and in vitro models, and they can replicate the living lung environment well while preserving the lungs' basic structures, such as their primitive cells and trachea. However, there is no perfect model that can completely replace the structure of the human lung, and there is still a long way to go in the research of lung slice technology. This review details and analyzes the strengths and weaknesses of precision lung slices as an in vitro model for exploring respiratory diseases associated with inflammation, as well as recent advances in this field.

Molecular Insight into the Therapeutic Effects of Stem Cell-Derived Exosomes in Respiratory Diseases and the Potential for Pulmonary Delivery

Respiratory diseases are the cause of millions of deaths annually around the world. Despite the recent growth of our understanding of underlying mechanisms contributing to the pathogenesis of lung diseases, most therapeutic approaches are still limited to symptomatic treatments and therapies that only delay disease progression. Several clinical and preclinical studies have suggested stem cell (SC) therapy as a promising approach for treating various lung diseases. However, challenges such as the potential tumorigenicity, the low survival rate of the SCs in the recipient body, and difficulties in cell culturing and storage have limited the applicability of SC therapy. SC-derived extracellular vesicles (SC-EVs), particularly SC-derived exosomes (SC-Exos), exhibit most therapeutic properties of stem cells without their potential drawbacks. Similar to SCs, SC-Exos exhibit immunomodulatory, anti-inflammatory, and antifibrotic properties with the potential to be employed in the treatment of various inflammatory and chronic respiratory diseases. Furthermore, recent studies have demonstrated that the microRNA (miRNA) content of SC-Exos may play a crucial role in the therapeutic potential of these exosomes. Several studies have investigated the administration of SC-Exos via the pulmonary route, and techniques for SCs and SC-Exos delivery to the lungs by intratracheal instillation or inhalation have been developed. Here, we review the literature discussing the therapeutic effects of SC-Exos against respiratory diseases and advances in the pulmonary route of delivery of these exosomes to the damaged tissues.

Emerging role of exosomes as biomarkers in cancer treatment and diagnosis

Cancer is a leading cause of death worldwide and cancer incidence and mortality are rapidly growing. These massive amounts of cancer patients require rapid diagnosis and efficient treatment strategies. However, the currently utilized methods are invasive and cost-effective. Recently, the effective roles of exosomes as promising diagnostic, prognostic, and predictive biomarkers have been revealed. Exosomes are membrane-bound extracellular vesicles containing RNAs, DNAs, and proteins, and are present in a wide array of body fluids. Exosomal cargos have shown the potential to detect various types of cancers at early stages with high sensitivity and specificity. They can also delivery therapeutic agents efficiently. In this article, an overview of recent advances in the research of exosomal biomarkers and their applications in cancer diagnosis and treatment has been provided. Furthermore, the advantages and challenges of exosomes as liquid biopsy targets are discussed and the clinical implications of using exosomal miRNAs have been revealed.

Viability assessment of human peripheral blood-derived stem cells after three methods of nebulization

BACKGROUND AND OBJECTIVES

Drug delivery by nebulization has become a crucial strategy for treating different respiratory and lung diseases. Emerging evidence implicates stem cell therapy as a promising tool in treating such conditions, not only by alleviating the related symptoms but by improving the prognosis. However, delivery of human peripheral blood-derived stem cells (hPBSCs) to the respiratory airways remains an innovative approach yet to be realized. This study is an analytic, translational, and in vitro research to assess the viability and morphological changes of identified cell populations in hPBSCs cocktail derived from COVID-19 patients.

METHODS AND RESULTS

Peripheral blood (PB) samples were obtained from patients enrolled in the SENTAD-COVID Study (ClinicalTrials.gov Reference: NCT04473170). hPBSCs cocktails (n=15) were provided by the Cells Processing Laboratory of Abu Dhabi Stem Cells Center, and were nebulized by three different methods of nebulization: compressor (jet), ultrasonic, and mesh. Our results reported that nucleated CD45^dim cell count was significantly lower after the three nebulization methods, but nucleated CD45^- cells show a significant decrease only after mesh nebulization. Mesh-nebulized samples had a significant reduction in viability of both CD45^dim and CD45^- cells.

CONCLUSIONS

This study provides evidence that stem cells derived from PB of COVID-19 patients can be nebulized without substantial loss of cell viability, cell count, and morphological changes using the compressor nebulization. Therefore, we recommend compressor nebulizers as the preferable procedure for hPBSCs delivery to the respiratory airways in further clinical settings.

Evaluation of Aerosol Drug Delivery Options during Adult Mechanical Ventilation in the COVID-19 Era

Drug delivery devices used for aerosol therapy during mechanical ventilation to ease the symptoms of respiratory diseases provide beneficial treatment but can also pose challenges. Reflecting the significant changes in global guidance around aerosol usage and lung-protective ventilation strategies, seen in response to the COVID-19 pandemic, for the first time, we describe the drug delivery performance of commonly used devices under these conditions. Here, vibrating mesh nebuliser (VMN), jet nebuliser (JN) and pressurised metered-dose inhaler (pMDI) performance was assessed during simulated adult mechanical ventilation. Both standard test breathing patterns and those representatives of low tidal volume (LTV) ventilation with concurrent active and passive humidification were investigated. Drug delivery using a VMN was significantly greater than that with a JN and pMDI for both standard and LTV ventilation. Humidification type did not affect the delivered dose across all device types for standard ventilation. Significant variability in the pMDI dosing was evident, depending on the timing of actuation and the adapter type used. pMDI actuation synchronised with inspiration resulted in a higher delivered drug dose. The type of adapter used for pMDI actuation influenced drug delivery, with the highest dose observed using the CombiHaler.

Cellular Immunotherapy and the Lung

The new era of cellular immunotherapies has provided state-of-the-art and efficient strategies for the prevention and treatment of cancer and infectious diseases. Cellular immunotherapies are at the forefront of innovative medical care, including adoptive T cell therapies, cancer vaccines, NK cell therapies, and immune checkpoint inhibitors. The focus of this review is on cellular immunotherapies and their application in the lung, as respiratory diseases remain one of the main causes of death worldwide. The ongoing global pandemic has shed a new light on respiratory viruses, with a key area of concern being how to combat and control their infections. The focus of cellular immunotherapies has largely been on treating cancer and has had major successes in the past few years. However, recent preclinical and clinical studies using these immunotherapies for respiratory viral infections demonstrate promising potential. Therefore, in this review we explore the use of multiple cellular immunotherapies in treating viral respiratory infections, along with investigating several routes of administration with an emphasis on inhaled immunotherapies.

Cellular Therapy for the Treatment of Paediatric Respiratory Disease

Respiratory disease is the leading cause of death in children under the age of 5 years old. Currently available treatments for paediatric respiratory diseases including bronchopulmonary dysplasia, asthma, cystic fibrosis and interstitial lung disease may ameliorate symptoms but do not offer a cure. Cellular therapy may offer a potential cure for these diseases, preventing disease progression into adulthood. Induced pluripotent stem cells, mesenchymal stromal cells and their secretome have shown great potential in preclinical models of lung disease, targeting the major pathological features of the disease. Current research and clinical trials are focused on the adult population. For cellular therapies to progress from preclinical studies to use in the clinic, optimal cell type dosage and delivery methods need to be established and confirmed. Direct delivery of these therapies to the lung as aerosols would allow for lower doses with a higher target efficiency whilst avoiding potential effect of systemic delivery. There is a clear need for research to progress into the clinic for the treatment of paediatric respiratory disease. Whilst research in the adult population forms a basis for the paediatric population, varying disease pathology and anatomical differences in paediatric patients means a paediatric-centric approach must be taken.

Cell therapy strategies for COVID-19: Current approaches and potential applications

Coronavirus disease 2019 (COVID-19) continues to burden society worldwide. Despite most patients having a mild course, severe presentations have limited treatment options. COVID-19 manifestations extend beyond the lungs and may affect the cardiovascular, nervous, and other organ systems. Current treatments are nonspecific and do not address potential long-term consequences such as pulmonary fibrosis, demyelination, and ischemic organ damage. Cell therapies offer great potential in treating severe COVID-19 presentations due to their customizability and regenerative function. This review summarizes COVID-19 pathogenesis, respective areas where cell therapies have potential, and the ongoing 89 cell therapy trials in COVID-19 as of 1 January 2021.

Compassionate mesenchymal stem cell treatment in a severe COVID-19 patient: a case report

COVID-19 presentations range from cold-like symptoms to severe symptoms with the development of acute respiratory distress syndrome (ARDS). We report on a severe COVID-19 patient who was mechanically ventilated and who developed ARDS and bacterial infection. Because of rapid clinical deterioration and the exhaustion of other treatment options, the family and attending physicians requested a compassionate use of adult allogeneic bone marrow-derived mesenchymal stem cells (MSC) in addition to commonly used immunosuppressive, antiviral, and supportive therapy. The clinical course is discussed thoroughly, with a special emphasis on the safety and effect of MSC therapy. Compassionate MSC treatment, given in three rounds, affected ARDS regression. The patient was discharged from the intensive care unit after 31 days and from hospital after 49 days in a good general condition. MSC treatment was not associated with any side effects and was well tolerated in a three-week period; therefore, it should be studied in larger trials and considered for compassionate use.

Adipose-Derived Stem Cells Secretome and Its Potential Application in "Stem Cell-Free Therapy"

Adipose-derived stem cells (ASCs) secrete many cytokines, proteins, growth factors, and extracellular vesicles with beneficial outcomes that can be used in regenerative medicine. It has great potential, and the development of new treatment strategies using the ASCs secretome is of global interest. Besides cytokines, proteins, and growth factors, the therapeutic effect of secretome is hidden in non-coding RNAs such as miR-21, miR-24, and miR-26 carried via exosomes secreted by adequate cells. The whole secretome, including ASC-derived exosomes (ASC-exos) has been proven in many studies to have immunomodulatory, proangiogenic, neurotrophic, and epithelization activity and can potentially be used for neurodegenerative, cardiovascular, respiratory, inflammatory, and autoimmune diseases as well as wound healing treatment. Due to limitations in the use of stem cells in cell-based therapy, its secretome with emphasis on exosomes seems to be a reasonable and safer alternative with increased effectiveness and fewer side effects. Moreover, the great advantage of cell-free therapy is the possibility of biobanking the ASCs secretome. In this review, we focus on the current state of knowledge on the use of the ASCs secretome in stem cell-free therapy.

Therapeutic Potential of Mesenchymal Stem Cells and Their Products in Lung Diseases-Intravenous Administration versus Inhalation

The number of publications studying the therapeutic use of stem cells has steadily increased since 2000. Compared to other applications, there has been little interest in the evaluation of mesenchymal stem cells (MSCs) and MSC-derived products (mostly extracellular vesicles) for the treatment of respiratory diseases. Due to the lack of efficient treatments for acute respiratory distress syndrome caused by infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the action of MSCs has also been studied. This review describes mode of action and use of MSCs and MSC-derived products in the treatment of lung diseases including the respective advantages and limitations of the products. Further, issues related to standardized production are addressed. Administration by inhalation of MSCs, compared to intravenous injection, could decrease cell damage by shear stress, eliminate the barrier to reach target cells in the alveoli, prevent thrombus formation in the pulmonary vasculature and retention in filter for extracorporeal membrane oxygenation. There is more feasible to deliver extracellular vesicles than MSCs with inhalers, offering the advantage of non-invasive and repeated administration by the patient. Major obstacles for comparison of results are heterogeneity of the products, differences in the treatment protocols and small study cohorts.

Safety and efficacy of autologous non-hematopoietic enriched stem cell nebulization in COVID-19 patients: a randomized clinical trial, Abu Dhabi 2020

BACKGROUND

The novel SARS-CoV-2 has caused the coronavirus disease 2019 (COVID-19) pandemic. Currently, with insufficient worldwide vaccination rates, identifying treatment solutions to reduce the impact of the virus is urgently needed.

METHOD

An adaptive, multicentric, open-label, and randomized controlled phase I/II clinical trial entitled the "SENTAD-COVID Study" was conducted by the Abu Dhabi Stem Cells Center under exceptional conditional approval by the Emirates Institutional Review Board (IRB) for COVID-19 Research Committee from April 4th to July 31st, 2020, using an autologous peripheral blood non-hematopoietic enriched stem cell cocktail (PB-NHESC-C) administered by compressor (jet) nebulization as a complement to standard care therapy. The primary endpoints include safety and efficacy assessments, adverse events, the mortality rate within 28 days, and the time to clinical improvement as measured by a 2-point reduction on a seven-category ordinal scale or discharge from the hospital whichever occurred first.

RESULTS

The study included a total of 139 randomized COVID-19 patients, with 69 in the experimental group and 70 in the control group (standard care). Overall survival was 94.20% for the cocktail-treated group vs. 90.27% for the control group. Adverse events were reported in 50 (72.46%) patients receiving PB-NHESC-C and 51 (72.85%) in the control group (p = 0.9590), with signs and symptoms commonly found in COVID-19. After the first 9 days of the intervention, 67.3% of cocktail-treated patients recovered and were released from hospitals compared to 53.1% (RR = 0.84; 95% CI, 0.56-1.28) in the control group. Improvement, i.e., at least a 2-point reduction in the severity scale, was more frequently observed in cocktail-treated patients (42.0%) than in controls (17.0%) (RR = 0.69; 95% CI, 0.56-0.88).

CONCLUSIONS

Cocktail treatment improved clinical outcomes without increasing adverse events. Thus, the nebulization of PB-NHESC-C was safe and effective for treatment in most of these patients.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT04473170. It was retrospectively registered on July 16th, 2020.

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.