Current status of cell-based therapies for respiratory virus infections: applicability to COVID-19

Cell therapies for viral diseases: a new frontier

Despite advances in medicine and antimicrobial research, viral infections continue to pose a major threat to human health. While major strides have been made in generating vaccines and small molecules to combat emerging pathogens, new modalities of treatment are warranted in diseases where there is a lack of treatment options, or where treatment cannot fully eradicate pathogens, as in HIV infection. Cellular therapies, some of which are FDA approved for treating cancer, take advantage of our developing understanding of the immune system, and harness this knowledge to enhance, or direct, immune responses toward infectious agents. As with cancer, viruses that evade immunity, do so by avoiding immune recognition or by redirecting the cellular responses that would eradicate them. As such, infusing virus specific immune cells has the potential to improve patient outcomes and should be investigated as a potential tool in the arsenal to fight infection. The present manuscript summarizes key findings made using cellular therapies for the treatment of viral infections, focusing on the potential that these strategies might have in controlling disease.

Unraveling the pathogenesis of viral-induced pulmonary arterial hypertension: Possible new therapeutic avenues with mesenchymal stromal cells and their derivatives

Pulmonary hypertension (PH) is a severe condition characterized by elevated pressure in the pulmonary artery, where metabolic and mitochondrial dysfunction may contribute to its progression. Within the PH spectrum, pulmonary arterial hypertension (PAH) stands out with its primary pulmonary vasculopathy. PAH's prevalence varies from 0.4 to 1.4 per 100,000 individuals and is associated with diverse conditions, including viral infections such as HIV. Notably, recent observations highlight an increased occurrence of PAH among COVID-19 patients, even in the absence of pre-existing cardiopulmonary disorders. While current treatments offer partial relief, there's a pressing need for innovative therapeutic strategies, among which mesenchymal stromal cells (MSCs) and their derivatives hold promise. This review critically evaluates recent investigations into viral-induced PAH, encompassing pathogens like human immunodeficiency virus, herpesvirus, Cytomegalovirus, Hepatitis B and C viruses, SARS-CoV-2, and Human endogenous retrovirus K (HERKV), with a specific emphasis on mitochondrial dysfunction. Furthermore, we explore the underlying rationale driving novel therapeutic modalities, including MSCs, extracellular vesicles, and mitochondrial interventions, within the framework of PAH management.

A review of immune modulators and immunotherapy in infectious diseases

The human immune system responds to harmful foreign invaders frequently encountered by the body and employs defense mechanisms to counteract such assaults. Various exogenous and endogenous factors play a prominent role in maintaining the balanced functioning of the immune system, which can result in immune suppression or immune stimulation. With the advent of different immune-modulatory agents, immune responses can be modulated or regulated to control infections and other health effects. Literature provides evidence on various immunomodulators from different sources and their role in modulating immune responses. Due to the limited efficacy of current drugs and the rise in drug resistance, there is a growing need for new therapies for infectious diseases. In this review, we aim to provide a comprehensive overview of different immune-modulating agents and immune therapies specifically focused on viral infectious diseases.

Harnessing immunity: Immunomodulatory therapies in COVID-19

An overly exuberant immune response, characterized by a cytokine storm and uncontrolled inflammation, has been identified as a significant driver of severe coronavirus disease 2019 (COVID-19) cases. Consequently, deciphering the intricacies of immune dysregulation in COVID-19 is imperative to identify specific targets for intervention and modulation. With these delicate dynamics in mind, immunomodulatory therapies have emerged as a promising avenue for mitigating the challenges posed by COVID-19. Precision in manipulating immune pathways presents an opportunity to alter the host response, optimizing antiviral defenses while curbing deleterious inflammation. This review article comprehensively analyzes immunomodulatory interventions in managing COVID-19. We explore diverse approaches to mitigating the hyperactive immune response and its impact, from corticosteroids and non-steroidal drugs to targeted biologics, including anti-viral drugs, cytokine inhibitors, JAK inhibitors, convalescent plasma, monoclonal antibodies (mAbs) to severe acute respiratory syndrome coronavirus 2, cell-based therapies (i.e., CAR T, etc.). By summarizing the current evidence, we aim to provide a clear roadmap for clinicians and researchers navigating the complex landscape of immunomodulation in COVID-19 treatment.

The Main Mechanisms of Mesenchymal Stem Cell-Based Treatments against COVID-19

BACKGROUND

Coronavirus disease 2019 (COVID-19) has a clinical manifestation of hypoxic respiratory failure and acute respiratory distress syndrome. However, COVID-19 still lacks of effective clinical treatments so far. As a promising potential treatment against COVID-19, stem cell therapy raised recently and had attracted much attention. Here we review the mechanisms of mesenchymal stem cell-based treatments against COVID-19, and provide potential cues for the effective control of COVID-19 in the future.

METHODS

Literature is obtained from databases PubMed and Web of Science. Key words were chosen for COVID- 19, acute respiratory syndrome coronavirus 2, mesenchymal stem cells, stem cell therapy, and therapeutic mechanism. Then we summarize and critically analyze the relevant articles retrieved.

RESULTS

Mesenchymal stem cell therapy is a potential effective treatment against COVID-19. Its therapeutic efficacy is mainly reflected in reducing severe pulmonary inflammation, reducing lung injury, improving pulmonary function, protecting and repairing lung tissue of the patients. Possible therapeutic mechanisms might include immunoregulation, anti-inflammatory effect, tissue regeneration, anti-apoptosis effect, antiviral, and antibacterial effect, MSC - EVs, and so on.

CONCLUSION

Mesenchymal stem cells can effectively treat COVID-19 through immunoregulation, anti-inflammatory, tissue regeneration, anti-apoptosis, anti-virus and antibacterial, MSC - EVs, and other ways. Systematically elucidating the mechanisms of mesenchymal stem cell-based treatments for COVID-19 will provide novel insights into the follow-up research and development of new therapeutic strategies in next step.

Olfactory mucosa mesenchymal stem cells alleviate pulmonary fibrosis via the immunomodulation and reduction of inflammation

BACKGROUND

Pulmonary fibrosis (PF) is a progressive fibrosing interstitial pneumonia that leads to respiratory failure and other complications, which is ultimately fatal. Mesenchymal stem cells (MSCs) transplant is a promising strategy to solve this problem, while the procurement of MSCs from the patient for autotransplant remains a challenge.

METHODS

Here, we presented olfactory mucosa mesenchymal stem cells (OM-MSCs) from mouse turbinate and determined the preventing efficacy of allotransplant for PF. We demonstrated the antiinflammation and immunomodulatory effects of OM-MSCs. Flow cytometric analysis was used to verify the effect of OM-MSCs on monocyte-derived macrophage populations in the lung.

RESULTS

Administration of OM-MSCs reduces inflammation, attenuates the matrix metallopeptidase 13 (MMP13) expression level and restores the bleomycin (BLM)-induced pulmonary fibrosis by assessing the architecture of lung, collagen type I; (COL1A1), actin alpha 2, smooth muscle, aorta (ACTA2/α-SMA) and hydroxyproline. This therapeutic effect of OM-MSCs was related to the increase in the ratio of nonclassical monocytes to proinflammatory monocytes in the lung.

CONCLUSIONS

This study suggests that transplant of OM-MSCs represents an effective and safe treatment for PF.

Mesenchymal Stem Cell-Based Therapies in the Post-Acute Neurological COVID Syndrome: Current Landscape and Opportunities

One of the main concerns related to SARS-CoV-2 infection is the symptoms that could be developed by survivors, known as long COVID, a syndrome characterized by persistent symptoms beyond the acute phase of the infection. This syndrome has emerged as a complex and debilitating condition with a diverse range of manifestations affecting multiple organ systems. It is increasingly recognized for affecting the Central Nervous System, in which one of the most prevalent manifestations is cognitive impairment. The search for effective therapeutic interventions has led to growing interest in Mesenchymal Stem Cell (MSC)-based therapies due to their immunomodulatory, anti-inflammatory, and tissue regenerative properties. This review provides a comprehensive analysis of the current understanding and potential applications of MSC-based interventions in the context of post-acute neurological COVID-19 syndrome, exploring the underlying mechanisms by which MSCs exert their effects on neuroinflammation, neuroprotection, and neural tissue repair. Moreover, we discuss the challenges and considerations specific to employing MSC-based therapies, including optimal delivery methods, and functional treatment enhancements.

Mesenchymal stem cells ameliorate H9N2-induced acute lung injury by inhibiting caspase-3-GSDME-mediated pyroptosis of lung alveolar epithelial cells

Influenza A virus infection mediates the host's excessive immune response, wherein caspase-3-GSDME-mediated pyroptosis of lung alveolar epithelial cells can contribute to inducing cytokine storm, leading to acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Numerous studies have shown that mesenchymal stem cells (MSCs) possess potent immunomodulatory abilities and can mitigate virus-induced cytokine storm and lung injury. However, the role of MSCs in lung pyroptosis remains poorly understood. In this study, we established an ALI model using a mouse-adapted strain of avian influenza virus H9N2 (MA01) and intervened by injecting appropriate bone marrow-derived mesenchymal stem cells (BMMSCs) into the mouse's trachea. The results obtained from animal experiments demonstrated that BMMSCs prevented and ameliorated ALI by inhibiting Caspase-3-GSDME-mediated pyroptosis of lung epithelial cells as well as hypercytokinemia. Similarly, corresponding results were observed in vitro, where BMMSCs and the lung epithelial cell line MLE-12 cells were co-cultured in a transwell compartment. Additionally, the caspase-3 inhibitor Z-DEVD-FMK could block MA01-induced GSDME activation. Furthermore, by combining RNA-Seq data with in vitro and in vivo results, we also discovered that MA01-induced pyroptosis is associated with the BAK/BAX-dependent mitochondrial apoptosis pathway. Notably, BMMSCs exhibit the ability to interfere with this signaling pathway. In conclusion, this study provides novel theoretical support for the utilization of BMMSCs in the treatment of ALI induced by influenza.

Mesenchymal Stem Cells in the Treatment of COVID-19

Since the emergence of the coronavirus disease 2019 (COVID-19) pandemic, many lives have been tragically lost to severe infections. The COVID-19 impact extends beyond the respiratory system, affecting various organs and functions. In severe cases, it can progress to acute respiratory distress syndrome (ARDS) and multi-organ failure, often fueled by an excessive immune response known as a cytokine storm. Mesenchymal stem cells (MSCs) have considerable potential because they can mitigate inflammation, modulate immune responses, and promote tissue regeneration. Accumulating evidence underscores the efficacy and safety of MSCs in treating severe COVID-19 and ARDS. Nonetheless, critical aspects, such as optimal routes of MSC administration, appropriate dosage, treatment intervals, management of extrapulmonary complications, and potential pediatric applications, warrant further exploration. These research avenues hold promise for enriching our understanding and refining the application of MSCs in confronting the multifaceted challenges posed by COVID-19.

hMSCs treatment attenuates murine herpesvirus-68 (MHV-68) pneumonia through altering innate immune response via ROS/NLRP3 signaling pathway

Immunocompromised individuals are particularly vulnerable to viral infections and reactivation, especially endogenous herpes viruses such as Epstein-Barr virus (EBV), a member of oncogenic gamma-herpesviruses, which are commonly linked to pneumonia and consequently significant morbidity and mortality. In the study of human and animal oncogenic gammaherpesviruses, the murine gamma-herpesviruses-68 (MHV-68) model has been applied, as it can induce pneumonia in immunocompromised mice. Mesenchymal stem cell (MSC) treatment has demonstrated therapeutic potential for pneumonia, as well as other forms of acute lung injury, in preclinical models. In this study, we aim to investigate the therapeutic efficacy and underlying mechanisms of human bone marrow-derived MSC (hMSC) on MHV-68-induced pneumonia. We found that intravenous administration of hMSCs significantly reduced lung damages, diminished inflammatory mediators and somehow inhibited MHV-68 replication. Furthermore, hMSCs treatment can regulate innate immune response and induce macrophage polarization from M1 to M2 phenotype, could significantly alter leukocyte infiltration and reduce pulmonary fibrosis. Our findings with co-culture system indicated that hMSCs effectively reduced the secretion of of inflammation-related factors and induced a shift in macrophage polarization, consistent with in vivo results. Further investigations revealed that hMSCs treatment suppressed the activation of macrophage ROS/NLRP3 signaling pathway in vivo and in vitro. Moreover, administration of MCC950, a selective NLRP3 inhibitor has been shown to effectively reduce ROS production and subsequently alleviate inflammation induced by MHV-68. Taken together, our work has shown that hMSCs can effectively protect mice from lethal MHV-68 pneumonia, which may throw new light on strategy for combating human EBV-associated pneumonia.

Rationale for combined therapies in severe-to-critical COVID-19 patients

An unprecedented global social and economic impact as well as a significant number of fatalities have been brought on by the coronavirus disease 2019 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Acute SARS-CoV-2 infection can, in certain situations, cause immunological abnormalities, leading to an anomalous innate and adaptive immune response. While most patients only experience mild symptoms and recover without the need for mechanical ventilation, a substantial percentage of those who are affected develop severe respiratory illness, which can be fatal. The absence of effective therapies when disease progresses to a very severe condition coupled with the incomplete understanding of COVID-19's pathogenesis triggers the need to develop innovative therapeutic approaches for patients at high risk of mortality. As a result, we investigate the potential contribution of promising combinatorial cell therapy to prevent death in critical patients.

Adipose-derived mesenchymal stem cell therapy for reverse bleomycin-induced experimental pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive respiratory disease. Arguably, the complex interplay between immune cell subsets, coupled with an incomplete understanding of disease pathophysiology, has hindered the development of successful therapies. Despite efforts to understand its pathophysiology and develop effective treatments, IPF remains a fatal disease, necessitating the exploration of new treatment options. Mesenchymal stromal/stem cell (MSC) therapy has shown promise in experimental models of IPF, but further investigation is needed to understand its therapeutic effect. This study aimed to assess the therapeutic effect of adipose-derived mesenchymal stem cells in a bleomycin-induced pulmonary fibrosis model. First, MSC cells were obtained from mice and characterized using flow cytometry and cell differentiation culture methods. Then adult C57BL/6 mice were exposed to endotracheal instillation of bleomycin and concurrently treated with MSCs for reversal models on day 14. Experimental groups were evaluated on days 14, 21, or 28. Additionally, lung fibroblasts challenged with TGF-β1 were treated with MSCs supernatant or MSCs to explore the mechanisms underlying of pulmonary fibrosis reversal. Mesenchymal stem cells were successfully isolated from mouse adipose tissue and characterized based on their differentiation ability and cell phenotype. The presence of MSCs or their supernatant stimulated the proliferation and migration of lung fibrotic cells. MSCs supernatant reduced lung collagen deposition, improved the Ashcroft score and reduced the gene and protein expression of lung fibrosis-related substances. Bleomycin-challenged mice exhibited severe septal thickening and prominent fibrosis, which was effectively reversed by MSCs treatment. MSC supernatant could suppress the TGF-β1/Smad signaling pathway and supernatant promotes fibroblast autophagy. In summary, this study demonstrates that MSCs supernatant treatment is as effective as MSCs in revert the core features of bleomycin-induced pulmonary fibrosis. The current study has demonstrated that MSCs supernatant alleviates the BLM-induced pulmonary fibrosis in vivo. In vitro experiments further reveal that MSC supernatant could suppress the TGF-β1/Smad signaling pathway to inhibit the TGF-β1-induced fibroblast activation, and promotes fibroblast autophagy by Regulating p62 expression. These findings contribute to the growing body of evidence supporting the therapeutic application of MSCs in cell therapy medicine for IPF.

Stromal cell therapy in cats with feline chronic gingivostomatitis: current perspectives and future direction

Feline chronic gingivostomatitis (FCGS) is a painful, immune-mediated, oral mucosal inflammatory disease in cats. The etiology of FCGS remains unclear, with evidence pointing potentially toward a viral cause. Full-mouth tooth extraction is the current standard of care, and cats that are non-responsive to extraction therapy may need lifelong medical management and, in some cases, euthanasia. Adipose-derived mesenchymal stromal cells (adMSCs) have been demonstrated to have advantages in the treatment and potentially the cure of non-responsive FCGS in cats. Therefore, adMSCs have attracted a series of ongoing clinical trials in the past decade. AdMSC therapy immediately after full-mouth tooth extraction was not explored, and we postulate that it may benefit the overall success rate of FCGS therapy. Here, we aim to summarize the current knowledge and impact of adMSCs for the therapeutic management of FCGS and to suggest a novel modified approach to further increase the efficacy of FCGS treatment in cats.

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.

Systematic review and meta-analysis of cell therapy for COVID-19: global clinical trial landscape, published safety/efficacy outcomes, cell product manufacturing and clinical delivery

During the pandemic of severe respiratory distress syndrome coronavirus 2 (SARS-CoV2), many novel therapeutic modalities to treat Coronavirus 2019 induced disease (COVID-19) were explored. This study summarizes 195 clinical trials of advanced cell therapies targeting COVID-19 that were registered over the two years between January 2020 to December 2021. In addition, this work also analyzed the cell manufacturing and clinical delivery experience of 26 trials that published their outcomes by July 2022. Our demographic analysis found the highest number of cell therapy trials for COVID-19 was in United States, China, and Iran (N=53, 43, and 19, respectively), with the highest number per capita in Israel, Spain, Iran, Australia, and Sweden (N=0.641, 0.232, 0,223, 0.194, and 0.192 trials per million inhabitants). The leading cell types were multipotent mesenchymal stromal/stem cells (MSCs), natural killer (NK) cells, and mononuclear cells (MNCs), accounting for 72%, 9%, and 6% of the studies, respectively. There were 24 published clinical trials that reported on infusions of MSCs. A pooled analysis of these MSC studies found that MSCs provide a relative risk reduction for all-cause COVID-19 mortality of RR=0.63 (95% CI 0.46 to 0.85). This result corroborates previously published smaller meta-analyses, which suggested that MSC therapy demonstrated a clinical benefit for COVID-19 patients. The sources of the MSCs used in these studies and their manufacturing and clinical delivery methods were remarkably heterogeneous, with some predominance of perinatal tissue-derived products. Our results highlight the important role that cell therapy products may play as an adjunct therapy in the management of COVID-19 and its related complications, as well as the importance of controlling key manufacturing parameters to ensure comparability between studies. Thus, we support ongoing calls for a global registry of clinical studies with MSC products that could better link cell product manufacturing and delivery methods to clinical outcomes. Although advanced cell therapies may provide an important adjunct treatment for patients affected by COVID-19 in the near future, preventing pathology through vaccination still remains the best protection to date. We conducted a systematic review and meta-analysis of advanced cell therapy clinical trials as potential novel treatment for COVID-19 (resulting from SARS-CoV-2 coronavirus infection), including analysis of the global clinical trial landscape, published safety/efficacy outcomes (RR/OR), and details on cell product manufacturing and clinical delivery. This study had a 2-year observation interval from start of January 2020 to end of December 2021, including a follow-up period until end of July to identify published outcomes, which covers the most vivid period of clinical trial activity, and is also the longest observation period studied until today. In total, we identified 195 registered advanced cell therapy studies for COVID-19, employing 204 individual cell products. Leading registered trial activity was attributed to the USA, China, and Iran. Through the end of July 2022, 26 clinical trials were published, with 24 out of 26 articles employing intravenous infusions (IV) of mesenchymal stromal/stem cell (MSC) products. Most of the published trials were attributed to China and Iran. The cumulative results from the 24 published studies employing infusions of MSCs indicated an improved survival (RR=0.63 with 95% Confidence Interval 0.46 to 0.85). Our study is the most comprehensive systematic review and meta-analysis on cell therapy trials for COVID-19 conducted to date, clearly identifying the USA, China, and Iran as leading advanced cell therapy trial countries for COVID-19, with further strong contributions from Israel, Spain, Australia and Sweden. Although advanced cell therapies may provide an important adjunct treatment for patients affected by COVID-19 in the future, preventing pathology through vaccination remains the best protection.

Mesenchymal stem cells induce dynamic immunomodulation of airway and systemic immune cells in vivo but do not improve survival for mice with H1N1 virus-induced acute lung injury

Introduction: Influenza A virus (IAV)-induced acute lung injury (ALI) is characterized by pronounced proinflammatory activation and respiratory lung dysfunction. In this study, we performed deep immune profiling on airway and circulating immune cells to examine the effect of immunomodulation and therapeutic outcomes of mesenchymal stem cells (MSCs) therapy in mice with IAV-induced ALI. Methods: Animals were inoculated intranasally with H1N1 IAV, followed by intravenous administration of vehicle, or human clinical-grade, bone marrow-derived MSCs 24-h later, and monitored for six days to evaluate the survival. In another set of animals, bronchoalveolar lavage (BAL) fluid and whole blood were collected three days after infection for flow or mass cytometry (CyTOF) immune profiling analysis. Results: Immune cell population and phenotypic shifts in blood were mapped by CyTOF. Increases were observed in granulocytes and myeloid-derived cells in blood from vehicle-treated animals. While MSC treatment accentuated changes in these populations, naïve B, antibody-secreting B cells, and T cells were decreased in MSC-treated animals at day 3. Compared to sham animals, IAV infection induced a significant 5.5-fold increase in BAL total cell counts, including CD4⁺ and CD8⁺ T cells, CD19⁺ B cells, CD11b + Ly6G + neutrophils, and CD11b + Ly6C + monocytes. MSC treatment significantly decreased BAL total cell counts in IAV-infected mice, specifically the number of infiltrating CD4⁺ T cells and CD11b + Ly6G + neutrophils. In contrast, there were increases in CD8⁺ T cells, B cells, and monocytes in the alveolar space in MSC-treated animals. Phenotypic immune cell profiling of blood and BAL revealed a significantly higher proportion of the monocyte population with the M2 phenotype (CD206) in MSC-treated animals; however, this failed to confer protective effects in the survival of infected mice or reduce viral titer in the lung. Further investigation revealed that MSCs were susceptible to IAV infection, leading to increased cell death and potentially affecting their efficacy. Conclusion: These findings provided in vivo evidence that MSCs promote the selective recruitment of immune cells to the site of infection during IAV infection, with reductions in proinflammatory phenotypes. However, MSCs offered no survival benefit in IAV-infected animals, possibly due to MSCs' H1N1 IAV susceptibility and subsequent cell death.

Investigational Use of Mesenchymal Stem/Stromal Cells and Their Secretome as Add-On Therapy in Severe Respiratory Virus Infections: Challenges and Perspectives

Serious manifestations of respiratory virus infections such as influenza and coronavirus disease 2019 (COVID-19) are associated with a dysregulated immune response and systemic inflammation. Treating the immunological/inflammatory dysfunction with glucocorticoids, Janus kinase inhibitors, and monoclonal antibodies against the interleukin-6 receptor has significantly reduced the risk of respiratory failure and death in hospitalized patients with severe COVID-19, but the proportion of those requiring invasive mechanical ventilation (IMV) and dying because of respiratory failure remains elevated. Treatment of severe influenza-associated pneumonia and acute respiratory distress syndrome (ARDS) with available immunomodulators and anti-inflammatory compounds is still not recommended. New therapies are therefore needed to reduce the use of IMV and the risk of death in hospitalized patients with rapidly increasing oxygen demand and systemic inflammation who do not respond to the current standard of care. This paper provides a critical assessment of the published clinical trials that have tested the investigational use of intravenously administered allogeneic mesenchymal stem/stromal cells (MSCs) and MSC-derived secretome with putative immunomodulatory/antiinflammatory/regenerative properties as add-on therapy to improve the outcome of these patients. Increased survival rates are reported in 5 of 12 placebo-controlled or open-label comparative trials involving patients with severe and critical COVID-19 and in the only study concerning patients with influenza-associated ARDS. Results are encouraging but inconclusive for the following reasons: small number of patients tested in each trial; differences in concomitant treatments and respiratory support; imbalances between study arms; differences in MSC source, MSC-derived product, dosing and starting time of the investigational therapy; insufficient/inappropriate reporting of clinical data. Solutions are proposed for improving the clinical development plan, with the aim of facilitating regulatory approval of the MSC-based investigational therapy for life-threatening respiratory virus infections in the future. Major issues are the absence of a biomarker predicting responsiveness to MSCs and MSC-derived secretome and the lack of pharmacoeconomic evaluations.

COVID-19 disease treatment: pivotal challenges in the arena of umbilical cord-mesenchymal stem cells (UC-MSCs)

This century's first major epidemic of a new coronavirus illness (2019-nCoV) was a tremendous shock to the healthcare system. The onset of the pandemic has caused severe economic and health shortages. At this time, there are no viable treatments for COVID-19. Several clinical studies using cell-based therapies, such as umbilical cord mesenchymal stem cells, have showed promising results (UC-MSCs). UC-MSCs have been the focus of much study because to their potential as a treatment option for COVID-19 patients. Cytokine release syndrome, often called cytokine storm, increases the risk of morbidity and mortality from COVID-19. It has been established that UC-MSCs may suppress and control both the adaptive and innate immune responses by modulating the release of immunostimulatory cytokines. The purpose of this study is to assess and clarify the use of UC-MSCs for the treatment of ARDS caused by COVID-19.

Extracellular vesicle-transmitted miR-671-5p alleviates lung inflammation and injury by regulating the AAK1/NF-κB axis

Mesenchymal stem cells regulate remote intercellular signaling communication via their secreted extracellular vesicles. Here, we report that menstrual blood-derived stem cells alleviate acute lung inflammation and injury via their extracellular vesicle-transmitted miR-671-5p. Disruption of this abundantly expressed miR-671-5p dramatically reduced the ameliorative effect of extracellular vesicles released by menstrual blood-derived stem cells on lipopolysaccharide (LPS)-induced pulmonary inflammatory injury. Mechanistically, miR-671-5p directly targets the kinase AAK1 for post-transcriptional degradation. AAK1 is found to positively regulate the activation of nuclear factor κB (NF-κB) signaling by controlling the stability of the inhibitory protein IκBα. This study identifies a potential molecular basis of how extracellular vesicles derived from mesenchymal stem cells improve pulmonary inflammatory injury and highlights the functional importance of the miR-671-5p/AAK1 axis in the progression of pulmonary inflammatory diseases. More importantly, this study provides a promising cell-based approach for the treatment of pulmonary inflammatory disorders through an extracellular vesicle-dependent pathway.

What is the need and why is it time for innovative models for understanding lung repair and regeneration?

Advances in tissue engineering continue at a rapid pace and have provided novel methodologies and insights into normal cell and tissue homeostasis, disease pathogenesis, and new potential therapeutic strategies. The evolution of new techniques has particularly invigorated the field and span a range from novel organ and organoid technologies to increasingly sophisticated imaging modalities. This is particularly relevant for the field of lung biology and diseases as many lung diseases, including chronic obstructive pulmonary disease (COPD) and idiopathic fibrosis (IPF), among others, remain incurable with significant morbidity and mortality. Advances in lung regenerative medicine and engineering also offer new potential avenues for critical illnesses such as the acute respiratory distress syndrome (ARDS) which also continue to have significant morbidity and mortality. In this review, an overview of lung regenerative medicine with focus on current status of both structural and functional repair will be presented. This will serve as a platform for surveying innovative models and techniques for study, highlighting the need and timeliness for these approaches.

Human Mesenchymal Stem Cell (hMSC) Donor Potency Selection for the "First in Cystic Fibrosis" Phase I Clinical Trial (CEASE-CF)

Human Mesenchymal Stem Cell (hMSC) immunotherapy has been shown to provide both anti-inflammatory and anti-microbial effectiveness in a variety of diseases. The clinical potency of hMSCs is based upon an initial direct hMSC effect on the pro-inflammatory and anti-microbial pathophysiology as well as sustained potency through orchestrating the host immunity to optimize the resolution of infection and tissue damage. Cystic fibrosis (CF) patients suffer from a lung disease characterized by excessive inflammation and chronic infection as well as a variety of other systemic anomalies associated with the consequences of abnormal cystic fibrosis transmembrane conductance regulator (CFTR) function. The application of hMSC immunotherapy to the CF clinical armamentarium is important even in the era of modulators when patients with an established disease still need anti-inflammatory and anti-microbial therapies. Additionally, people with CF mutations not addressed by current modulator resources need anti-inflammation and anti-infection management. Furthermore, hMSCs possess dynamic therapeutic properties, but the potency of their products is highly variable with respect to their anti-inflammatory and anti-microbial effects. Due to the variability of hMSC products, we utilized standardized in vitro and in vivo models to select hMSC donor preparations with the greatest potential for clinical efficacy. The models that were used recapitulate many of the pathophysiologic outcomes associated with CF. We applied this strategy in pursuit of identifying the optimal donor to utilize for the "First in CF" Phase I clinical trial of hMSCs as an immunotherapy and anti-microbial therapy for people with cystic fibrosis. The hMSCs screened in this study demonstrated significant diversity in antimicrobial and anti-inflammatory function using models which mimic some aspects of CF infection and inflammation. However, the variability in activity between in vitro potency and in vivo effectiveness continues to be refined. Future studies require and in-depth pursuit of hMSC molecular signatures that ultimately predict the capacity of hMSCs to function in the clinical setting.

M. Rocco P, Cuenca J. Safety and efficacy of clinical-grade, cryopreserved menstrual blood mesenchymal stromal cells in experimental acute respiratory distress syndrome

Background: Treatment for critical care conditions, such as acute respiratory distress syndrome (ARDS), requires ready-to-administer injectable mesenchymal stromal cells (MSCs). A validated cryopreserved therapy based on MSCs derived from menstrual blood (MenSCs) is an attractive option that offers advantages over freshly cultured cells and allows its use as an off-the-shelf therapy in acute clinical conditions. The main goal of this study is to provide evidence on the impact of cryopreservation on different biological functions of MenSCs and to determine the optimal therapeutic dose, safety, and efficacy profile of clinical-grade, cryopreserved (cryo)-MenSCs in experimental ARDS. Methods: Biological functions of fresh versus cryo-MenSCs were compared in vitro. The effects of cryo-MenSCs therapy were evaluated in vivo in ARDS-induced (Escherichia coli lipopolysaccharide) C57BL/6 mice. After 24 h, the animals were treated with five doses ranging from 0.25×10⁵ to 1.25×10⁶ cells/animal. At 2 and 7 days after induction of ARDS, safety and efficacy were evaluated. Results: Clinical-grade cryo-MenSCs injections improved lung mechanics and reduced alveolar collapse, tissue cellularity, and remodelling, decreasing elastic and collagen fiber content in alveolar septa. In addition, administration of these cells modulated inflammatory mediators and promoted pro-angiogenic and anti-apoptotic effects in lung-injured animals. More beneficial effects were observed with an optimal dose of 4×10⁶ cells/Kg than with higher or lower doses. Conclusion: From a translational perspective, the results showed that clinical-grade cryopreserved MenSCs retain their biological properties and exert a therapeutic effect in mild to moderate experimental ARDS. The optimal therapeutic dose was well-tolerated, safe, and effective, favouring improved lung function. These findings support the potential value of an off-the-shelf MenSCs-based product as a promising therapeutic strategy for treating ARDS.

Regenerative medicine in lung diseases: A systematic review

Regenerative medicine has opened the door to the exploration of new therapeutic methods for the treatment of various diseases, especially those associated with local or general disregulation of the immune system. In pulmonary diseases, new therapeutic strategies have emerged that are aimed at restoring functional lung tissue rather than alleviating symptoms. These strategies focus on tissue regeneration using stem cells and/or their derivatives or replacement of dysfunctional tissue using biomedical engineering. Animal health can directly benefit from regenerative therapy strategies and also serve as a translational experimental model for human disease. Several clinical trials have been conducted to evaluate the effects of cellular treatment on inflammatory lung disease in animals. Data reported to date show several beneficial effects in ex vivo and in vivo models; however, our understanding of the mechanisms that regenerative therapies exert on diseased tissues remains incomplete.

Predicting multipotency of human adult stem cells derived from various donors through deep learning

Adult stem cell-based therapeutic approaches have great potential in regenerative medicine because of their immunoregulatory properties and multidifferentiation capacity. Nevertheless, the outcomes of stem cell‑based therapies to date have shown inconsistent efficacy owing to donor variation, thwarting the expectation of clinical effects. However, such donor dependency has been elucidated by biological consequences that current research could not predict. Here, we introduce cellular morphology-based prediction to determine the multipotency rate of human nasal turbinate stem cells (hNTSCs), aiming to predict the differentiation rate of keratocyte progenitors. We characterized the overall genes and morphologies of hNTSCs from five donors and compared stemness-related properties, including multipotency and specific lineages, using mRNA sequencing. It was demonstrated that transformation factors affecting the principal components were highly related to cell morphology. We then performed a convolutional neural network-based analysis, which enabled us to assess the multipotency level of each cell group based on their morphologies with 85.98% accuracy. Surprisingly, the trend in expression levels after ex vivo differentiation matched well with the deep learning prediction. These results suggest that AI‑assisted cellular behavioral prediction can be utilized to perform quantitative, non-invasive, single-cell, and multimarker characterizations of live stem cells for improved quality control in clinical cell therapies.

A comprehensive review on pharmacologic agents, immunotherapies and supportive therapeutics for COVID-19

The emergence of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected many countries throughout the world. As urgency is a necessity, most efforts have focused on identifying small molecule drugs that can be repurposed for use as anti-SARS-CoV-2 agents. Although several drug candidates have been identified using in silico method and in vitro studies, most of these drugs require the support of in vivo data before they can be considered for clinical trials. Several drugs are considered promising therapeutic agents for COVID-19. In addition to the direct-acting antiviral drugs, supportive therapies including traditional Chinese medicine, immunotherapies, immunomodulators, and nutritional therapy could contribute a major role in treating COVID-19 patients. Some of these drugs have already been included in the treatment guidelines, recommendations, and standard operating procedures. In this article, we comprehensively review the approved and potential therapeutic drugs, immune cells-based therapies, immunomodulatory agents/drugs, herbs and plant metabolites, nutritional and dietary for COVID-19.

A comparison of conventional and advanced electroanalytical methods to detect SARS-CoV-2 virus: A concise review

Respiratory viruses are a serious threat to human wellbeing that can cause pandemic disease. As a result, it is critical to identify virus in a timely, sensitive, and precise manner. The present novel coronavirus-2019 (COVID-19) disease outbreak has increased these concerns. The research of developing various methods for COVID-19 virus identification is one of the most rapidly growing research areas. This review article compares and addresses recent improvements in conventional and advanced electroanalytical approaches for detecting COVID-19 virus. The popular conventional methods such as polymerase chain reaction (PCR), loop mediated isothermal amplification (LAMP), serology test, and computed tomography (CT) scan with artificial intelligence require specialized equipment, hours of processing, and specially trained staff. Many researchers, on the other hand, focused on the invention and expansion of electrochemical and/or bio sensors to detect SARS-CoV-2, demonstrating that they could show a significant role in COVID-19 disease control. We attempted to meticulously summarize recent advancements, compare conventional and electroanalytical approaches, and ultimately discuss future prospective in the field. We hope that this review will be helpful to researchers who are interested in this interdisciplinary field and desire to develop more innovative virus detection methods.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: Promising Treatment for COVID-19 Pandemic

The pandemic of severe acute respiratory syndrome coronavirus-2 infection has prompted the urgent need for novel therapeutic approaches, especially for patients in critically severe conditions. To date, the pathogenesis of COVID-19 is not completely understood, and finding an effective new drug is still inconclusive. Mesenchymal stromal cell-derived extracellular vesicles contain large amounts of proteins, messenger RNA, and microRNAs that act as vehicles that transfer the cargo between cells. These nanotherapeutic materials exert anti-inflammatory effects on the immune system, which are necessary for subsidence of acute inflammation and promotion of tissue repair and regeneration. Therefore, the consideration of mesenchymal stromal cell-derived extracellular vesicles as a new, safe, and effective therapeutic approach in the treatment of COVID-19 pneumonia is suggested.

MSC-Derived exosomes suppress colorectal cancer cell proliferation and metastasis via miR-100/mTOR/miR-143 pathway

Exosomes derived from mesenchymal stem cells (MSCs) are mostly responsible for the therapeutic effects of MSCs. To show the therapeutic effects of the human bone marrow MSC-derived exosomes (MSC-Exos) on colorectal cancer (CRC) and explore the molecular cross-talks between them, CRC cells were treated with the MSC-Exos. We found that MSC-Exos were enriched with miR-100 and miR-143, which effectively downregulated mTOR, Cyclin D1, K-RAS, HK2 while upregulated p-27 expression. All these effects were reversed by concurrent treatment with MSC-Exos and antagomiR-100, confirming that they were caused by exosomal transfer of miR-100 into recipient CRC cells. Moreover, exosomal miR-100 promoted endogenous miR-143 expression. The flow cytometry, MTT and trypan blue assays revealed that MSC-Exos could efficiently suppress proliferation and induce apoptosis of the CRC cells. Furthermore, wound healing, transwell migration and invasion assays confirmed their inhibitory effects on the migration and invasiveness of SW480 cells. We further confirmed these effects by analyzing the expression levels of epithelial to mesenchymal transition (EMT) factors and metastasis-related genes. Results showed that MSC-Exos significantly suppressed the expression of MMP2 and MMP9 (metastasis-related genes), SNAIL and TWIST (EMT-inducing transcription factors), Vimentin and N-cadherin (mesenchymal cell markers), whereas E-cadherin (epithelial cell marker) was remarkably up-regulated. Collectively, our data indicated that MSC-Exos could suppress proliferation, migration, invasion and metastasis while inducing the apoptosis of the CRC cells via miR-100/mTOR/miR-143 axis. Our findings highlight that MSC-Exo treatment as well as miR-100 restoration might be considered as potential therapeutic strategies for CRC.

Pyroptotic cell death in SARS-CoV-2 infection: revealing its roles during the immunopathogenesis of COVID-19

The rapid dissemination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), remains a global public health emergency. The host immune response to SARS-CoV-2 plays a key role in COVID-19 pathogenesis. SARS-CoV-2 can induce aberrant and excessive immune responses, leading to cytokine storm syndrome, autoimmunity, lymphopenia, neutrophilia and dysfunction of monocytes and macrophages. Pyroptosis, a proinflammatory form of programmed cell death, acts as a host defense mechanism against infections. Pyroptosis deprives the replicative niche of SARS-CoV-2 by inducing the lysis of infected cells and exposing the virus to extracellular immune attack. Notably, SARS-CoV-2 has evolved sophisticated mechanisms to hijack this cell death mode for its own survival, propagation and shedding. SARS-CoV-2-encoded viral products act to modulate various key components in the pyroptosis pathways, including inflammasomes, caspases and gasdermins. SARS-CoV-2-induced pyroptosis contriubtes to the development of COVID-19-associated immunopathologies through leakage of intracellular contents, disruption of immune system homeostasis or exacerbation of inflammation. Therefore, pyroptosis has emerged as an important mechanism involved in COVID-19 immunopathogenesis. However, the entangled links between pyroptosis and SARS-CoV-2 pathogenesis lack systematic clarification. In this review, we briefly summarize the characteristics of SARS-CoV-2 and COVID-19-related immunopathologies. Moreover, we present an overview of the interplay between SARS-CoV-2 infection and pyroptosis and highlight recent research advances in the understanding of the mechanisms responsible for the implication of the pyroptosis pathways in COVID-19 pathogenesis, which will provide informative inspirations and new directions for further investigation and clinical practice. Finally, we discuss the potential value of pyroptosis as a therapeutic target in COVID-19. An in-depth discussion of the underlying mechanisms of COVID-19 pathogenesis will be conducive to the identification of potential therapeutic targets and the exploration of effective treatment measures aimed at conquering SARS-CoV-2-induced COVID-19.

Hemostatic system and COVID-19 crosstalk: A review of the available evidence

Since the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its resultant coronavirus disease 2019 (COVID-19) pandemic, respiratory manifestations have been the mainstay of clinical diagnosis, laboratory evaluations, and radiological investigations. As time passed, other pathological aspects of SARS-CoV-2 have been revealed. Various hemostatic abnormalities have been reported since the rise of the pandemic, which was sometimes superficial, transient, or fatal. Mild thrombocytopenia, thrombocytosis, venous, arterial thromboembolism, and disseminated intravascular coagulation are among the many hemostatic events associated with COVID-19. Venous thromboembolism necessitating therapeutic doses of anticoagulants is more frequently seen in severe cases of COVID-19, especially in patients admitted to intensive care units. Hemorrhagic complications rarely arise in COVID-19 patients either due to a hemostatic imbalance resulting from severe disease or as a complication of over anticoagulation. Although the pathogenesis of coagulation disturbance in SARS-CoV-2 infection is not yet understood, professional societies recommend prophylactic antithrombotic therapy in severe cases, especially in the presence of abnormal coagulation indices. The review article discusses the various available evidence on coagulation disorders, management strategies, outcomes, and prognosis associated with COVID-19 coagulopathy, which raises awareness about the importance of anticoagulation therapy for COVID-19 patients to guard against possible thromboembolic events.

Interrelation between extracellular vesicles miRNAs with chronic lung diseases

Extracellular vehicles (EVs) are nanoscale lipid bilayer vesicles that carry biologically active biomolecule cargos like proteins, lipids, and nucleic acids (DNA, RNA) outside of the cell. Blood (serum/plasma), urine, and bronchoalveolar lavage fluid are all examples of biofluids from which they may be collected. EVs play a vital role in intracellular communication. The molecular signature of EVs largely depends on the parental cell's status. EVs are classified into two groups, (1) exosomes (originated by endogenous route) and (2) microvesicles (originated from the plasma membrane, also known as ectosomes). The quantity and types of EV cargo vary during normal conditions compared to pathological conditions (chronic inflammatory lung diseases or lung cancer). Consequently, EVs contain novel biomarkers that differ based on the cell type of origin and during lung diseases. Small RNAs (e.g., microRNAs) are transported by EVs, which is one of the most rapidly evolving research areas in the field of EVs biology. EV-mediated cargos transport small RNAs that can result in reprograming the target/recipient cells. Multiple chronic inflammatory lung illnesses, such as chronic obstructive pulmonary disease, asthma, pulmonary hypertension, pulmonary fibrosis, cystic fibrosis, acute lung injury, and lung cancer, have been demonstrated to be regulated by EV. In this review, we will consolidate the current knowledge and literature on the novel role of EVs and their small RNAs concerning chronic lung diseases (CLDs). Additionally, we will also provide better insight into the clinical and translational impact of mesenchymal stem cells-derived EVs as novel therapeutic agents in treating CLDs.

Failed clinical trials on COVID-19 acute respiratory distress syndrome in hospitalized patients: common oversights and streamlining the development of clinically effective therapeutics

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has put a strain on global healthcare systems. Despite admirable efforts to develop rapidly new pharmacotherapies, supportive treatments remain the standard of care. Multiple clinical trials have failed due to design issues, biased patient enrollment, small sample sizes, inadequate control groups, and lack of long-term outcomes monitoring.

AREAS COVERED

This narrative review depicts the current situation around failed and success COVID-19 clinical trials and recommendations in hospitalized patients with COVID-19, oversights and streamlining of clinically effective therapeutics. PubMed, EBSCO, Cochrane Library, and WHO and NIH guidelines were searched for relevant literature up to 5 August 2022.

EXPERT OPINION

The WHO, NIH, and IDSA have issued recommendations to better clarify which drugs should be used during the different phases of the disease. Given the biases and high heterogeneity of published studies, interpretation of the current literature is difficult. Future clinical trials should be designed to standardize clinical approaches, with appropriate organization, patient selection, addition of control groups, and careful identification of disease phase to reduce heterogeneity and bias and should rely on the integration of scientific societies to promote a consensus on interpretation of the data and recommendations for optimal COVID-19 therapies.

Stem cell-based therapy for human diseases

Recent advancements in stem cell technology open a new door for patients suffering from diseases and disorders that have yet to be treated. Stem cell-based therapy, including human pluripotent stem cells (hPSCs) and multipotent mesenchymal stem cells (MSCs), has recently emerged as a key player in regenerative medicine. hPSCs are defined as self-renewable cell types conferring the ability to differentiate into various cellular phenotypes of the human body, including three germ layers. MSCs are multipotent progenitor cells possessing self-renewal ability (limited in vitro) and differentiation potential into mesenchymal lineages, according to the International Society for Cell and Gene Therapy (ISCT). This review provides an update on recent clinical applications using either hPSCs or MSCs derived from bone marrow (BM), adipose tissue (AT), or the umbilical cord (UC) for the treatment of human diseases, including neurological disorders, pulmonary dysfunctions, metabolic/endocrine-related diseases, reproductive disorders, skin burns, and cardiovascular conditions. Moreover, we discuss our own clinical trial experiences on targeted therapies using MSCs in a clinical setting, and we propose and discuss the MSC tissue origin concept and how MSC origin may contribute to the role of MSCs in downstream applications, with the ultimate objective of facilitating translational research in regenerative medicine into clinical applications. The mechanisms discussed here support the proposed hypothesis that BM-MSCs are potentially good candidates for brain and spinal cord injury treatment, AT-MSCs are potentially good candidates for reproductive disorder treatment and skin regeneration, and UC-MSCs are potentially good candidates for pulmonary disease and acute respiratory distress syndrome treatment.

hLMSC Secretome Affects Macrophage Activity Differentially Depending on Lung-Mimetic Environments

Mesenchymal stromal cell (MSC)-based therapies for inflammatory diseases rely mainly on the paracrine ability to modulate the activity of macrophages. Despite recent advances, there is scarce information regarding changes of the secretome content attributed to physiomimetic cultures and, especially, how secretome content influence on macrophage activity for therapy. hLMSCs from human donors were cultured on devices developed in house that enabled lung-mimetic strain. hLMSC secretome was analyzed for typical cytokines, chemokines and growth factors. RNA was analyzed for the gene expression of CTGF and CYR61. Human monocytes were differentiated to macrophages and assessed for their phagocytic capacity and for M1/M2 subtypes by the analysis of typical cell surface markers in the presence of hLMSC secretome. CTGF and CYR61 displayed a marked reduction when cultured in lung-derived hydrogels (L-Hydrogels). The secretome showed that lung-derived scaffolds had a distinct secretion while there was a large overlap between L-Hydrogel and the conventionally (2D) cultured samples. Additionally, secretome from L-Scaffold showed an HGF increase, while IL-6 and TNF-α decreased in lung-mimetic environments. Similarly, phagocytosis decreased in a lung-mimetic environment. L-Scaffold showed a decrease of M1 population while stretch upregulated M2b subpopulations. In summary, mechanical features of the lung ECM and stretch orchestrate anti-inflammatory and immunosuppressive outcomes of hLMSCs.

ACE2 overexpressing mesenchymal stem cells alleviates COVID-19 lung injury by inhibiting pyroptosis

Mesenchymal stem cells (MSCs) have shown some efficacy in the COVID-19 treatment. We proposed that exogenous supplementation of ACE2 via MSCs (ACE2-MSCs) might have better therapeutic effects. We constructed SARS-CoV-2 spike glycoprotein stably transfected AT-II and Beas-2B cells and used SARS-CoV-2 spike pseudovirus to infect hACE2 transgenic mice. The results showed that spike glycoprotein transfection triggers the release of apoptotic bodies and formation of membrane pores in pyroptosis. Inflammatory factors and pyroptosis factors were highly upregulated by spike glycoprotein transfection. SARS-CoV-2 spike pseudovirus worsened lung injury and increased the main factors of cytokine storm and pyroptosis. Compared to using MSCs or rh-ACE2 alone, the administration of ACE2-MSCs could significantly reduce these factors better and alleviate lung injury in vivo and in vitro, which might be because of the increased activities of secretory ACE2. Our proposal is a promising therapeutic solution for preclinical or clinical research.

Efficacy and safety of mesenchymal stem cells in the treatment of systemic sclerosis: a systematic review and meta-analysis

Background

Systemic sclerosis (SSc) is an autoimmune disease with high morbidity and mortality characterized by fibrosis of the skin and internal organs. Some studies have investigated the use of stem cells to treat SSc. Herein, a systematic review and meta-analysis was conducted to determine the efficacy and safety of mesenchymal stem cells (MSCs) in the treatment of SSc.

Methods

PubMed, Embase, Cochrane Library, Web of Science, OVID, China National Knowledge Infrastructure and Wanfang databases were searched up to February 1, 2021. Literature screening, data extraction and quality assessment were conducted independently by two researchers in according to the inclusion and exclusion criteria. The discrepancies were resolved by a third researcher.

Results

A total of 9 studies encompassing 133 SSc patients were included in the study. Compared to the baseline after treatment with MSCs: 1. The modified Rodnan skin score (mRSS) was significantly reduced in patients with SSc (P < 0.00001). 2. MSCs decreased the number of digital ulcer, mouth handicap scale, and visual analog scale of hand pain in SSc patients (P = 0.0007 and P = 0.03, respectively). 3. No statistical differences were detected in Raynaud's condition score and Cochin hand function scale score at 6 months of MSCs therapy (P = 0.5 and P = 0.62). 4. After 12 months of follow-up, MSCs improve carbon monoxide diffusing capacity and forced vital capacity of SSc patients (P < 0.05). 5. Overall, MSCs application was safe; a few cases exhibited swelling at the injection site, diarrhea and arthralgia, which had self-recovery, and no severe adverse events occurred in the included trials.

Conclusions

MSC therapy improves the degree of skin thickening, lung function, and mouth opening and relieves finger ulcers and pain in patients with SSc without severe adverse events. Thus, MSCs or MSCs combined with plasma and traditional medicine might be an effective and promising treatment of SSc patients.

PROSPERO registration number: CRD42020200350

Human Mesenchymal Stem/Stromal Cells in Immune Regulation and Therapy

Studies of mesenchymal stem (or stromal) cells (MSCs) have moved from bedside to bench and back again. The stromal cells or fibroblasts are found in all tissues and participate in building the extracellular matrix (ECM). Bone marrow (BM)-derived MSCs have been studied for more than 50 years and have multiple roles. They function as stem cells and give rise to bone, cartilage, and fat in the BM (these are stem cells); support hematopoiesis (pericytes); and participate in sensing environmental changes and balancing pro- and anti-inflammatory conditions. In disease states, they migrate to sites of injury and release cytokines, hormones, nucleic acids depending on the microenvironment they find. Clinicians have begun to exploit these properties of BM, adipose tissue, and umbilical cord MSCs because they are easy to harvest and expand in culture. In this review, I describe the uses to which MSCs have been put, list ongoing clinical trials by organ system, and outline how MSCs are thought to regulate the innate and adaptive immune systems. I will discuss some of the reasons why clinical applications are still lacking. Much more work will have to be done to find the sources, doses, and culture conditions needed to exploit MSCs optimally and learn their healing potential. They are worth the effort.

Mesenchymal stem cell treatment for COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has caused a global pandemic since late 2019 that resulted in more than 360 million population infection. Among them, less than 7% of infected individuals develop severe or critical illness. Mass vaccination has been carried out, but reinfection and vaccine breakthrough cases still occur. Besides supportive and antiviral medications, much attention has been paid in immunotherapies that aim at reducing pathological changes in the lungs. Mesenchymal stem cells (MSCs) is used as an option because of their immunomodulatory, anti-inflammatory, and regenerative properties. As of January 16, 2022, when ClinicalTrials.gov was searched for "Mesenchymal stem cells and COVID-19," over 80 clinical trials were registered. MSC therapy was found to be safe and some effective in preclinical and clinical studies. Here, we summarize the major pathological characteristics of COVID-19 and provide scientific and rational evidence for the safety and possible effectiveness of MSCs in COVID-19 treatment.

Safety and efficacy study of allogeneic human menstrual blood stromal cells secretome to treat severe COVID-19 patients: clinical trial phase I & II

BACKGROUND

Cell-free Mesenchymal stromal cells (MSCs) have been considered due to their capacity to modulate the immune system and suppress cytokine storms caused by SARS-CoV-2. This prospective randomized double-blind placebo-controlled clinical trial aimed to assess the safety and efficacy of secretome derived from allogeneic menstrual blood stromal cells (MenSCs) as a treatment in patients with severe COVID-19.

METHODS

Patients with severe COVID-19 were randomized (1:1) to either MenSC-derived secretome treatment or the control group. Subjects received five intravenous infusions of 5 mL secretome or the same volume of placebo for five days and were monitored for safety and efficacy for 28 days after treatment. Adverse events, laboratory parameters, duration of hospitalization, clinical symptom improvement, dynamic of O₂ saturation, lymphocyte number, and serial chest imaging were analyzed.

RESULTS

All safety endpoints were observed without adverse events after 72 h of secretome injection. Within 28 days after enrollment, 7 patients (50%) were intubated in the treated group versus 12 patients (80%) in the control group. Overall, 64% of patients had improved oxygen levels within 5 days of starting treatment (P < 0.0001) and there was a survival rate of 57% in the treatment group compared to 28% in the control group was (P < 0.0001). Laboratory values revealed that significant acute phase reactants declined, with mean C-reactive protein, ferritin, and D-dimer reduction of 77% (P < 0.001), 43% (P < 0.001), and 42% (P < 0.05), respectively. Significant improvement in lymphopenia was associated with an increase in mean CD4⁺ and CD8⁺ lymphocyte counts of 20% (P = 0.06) and 15% (P < 0.05), respectively. Following treatment, percentage of pulmonary involvement showed a significant improvement in the secretome group (P < 0.0001). This improvement differed significantly between survivors and those who were dying (P < 0.005).

CONCLUSIONS

For the first time, this study demonstrated that in hospitalized patients with severe COVID-19, therapy with MenSCs-derived secretome leads to reversal of hypoxia, immune reconstitution, and downregulation of cytokine storm, with no adverse effects attributable to the treatment. Given these outcomes, it may be possible to use this type of treatment for serious inflammatory lung disease with a mechanism similar to COVID-19 in the future. However, it is necessary to evaluate the safety and efficacy of MenSCs-derived secretome therapy in clinical trials on a larger population of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05019287. Registered 24AGUEST 2021, retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT05019287 . IRCT, IRCT20180619040147N6. Registered 04/01/2021.

Mesenchymal Stem Cells in the Treatment of New Coronavirus Pandemic: A Novel Promising Therapeutic Approach

After severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) outbreaks, coronavirus disease 2019 (COVID-19) is the third coronavirus epidemic that soon turned into a pandemic. This virus causes acute respiratory syndrome in infected people. The mortality rate of SARS-CoV-2 infection will probably rise unless efficient treatments or vaccines are developed. The global funding and medical communities have started performing more than five hundred clinical examinations on a broad spectrum of repurposed drugs to acquire effective treatments. Besides, other novel treatment approaches have also recently emerged, including cellular host-directed therapies. They counteract the unwanted responses of the host immune system that led to the severe pathogenesis of SARS-CoV-2. This brief review focuses on mesenchymal stem cell (MSC) principles in treating the COVID-19. The US clinical trials database and the world health organization database for clinical trials have reported 82 clinical trials (altogether) exploring the effects of MSCs in COVID-19 treatment. MSCs also had better be tried for treating other pathogens worldwide. MSC treatment may have the potential to end the high mortality rate of COVID-19. Besides, it also limits the long-term inability of survivors.

A Pan-Cancer In Silico Analysis of the COVID-19 Internalization Protease: Transmembrane Proteaseserine-2

The new coronavirus (2019-nCoV) is an emerging pathogen that can cause severe respiratory infections in humans. It is worth noting that many of the affected COVID-19 patients have malignant tumors. In addition, cancer has been identified as a personal risk factor for COVID-19. Transmembrane proteaseserine-2 (TMPRSS2) is a crucial host protease that mediates S protein activation and initially promotes virus entry into host cells. Moreover, it is abnormally expressed in a variety of tumors. However, the systematic analysis of TMPRSS2 aberrations in human cancer remains to be elucidated. Here, we analyzed the genetic changes, RNA expression, and DNA methylation of TMPRSS2 in more than 30 tumors. It has been reported that TMPRSS2 is overexpressed in tumors such as prostate adenocarcinoma (PRAD), and in contrast, the expression of TMPRSS2 is decreased in tumors such as head and neck cancer (HNSC). In addition, TMPRSS2 low DNA methylation was also found in most of these TMPRSS2 high-expressing tumors in this study. Clinical studies have found that there is a significant correlation between the expression of TMPRSS2 and the prognosis of some tumor patients. The expression of TMPRSS2 is also related to the infiltration of cancer-related fibroblasts, and the potential pathways and functional mechanisms were analyzed through KEGG/GO enrichment. In the end, our study planned the genetic and epigenetic variation of TMPRSS2 in human malignant tumors for the first time and provided a relatively comprehensive understanding of the carcinogenic effects of TMPRSS2.

Treatment of COVID-19-associated ARDS with mesenchymal stromal cells: a multicenter randomized double-blind trial

Background

Severe acute respiratory syndrome coronavirus-2 (SARS–CoV-2)-induced acute respiratory distress syndrome (ARDS) causes high mortality. Umbilical cord-derived mesenchymal stromal cells (UC-MSCs) have potentially relevant immune-modulatory properties, whose place in ARDS treatment is not established. This phase 2b trial was undertaken to assess the efficacy of UC-MSCs in patients with SARS–CoV-2-induced ARDS.

Methods

This multicentre, double-blind, randomized, placebo-controlled trial (STROMA–CoV-2) recruited adults (≥ 18 years) with SARS–CoV-2-induced early (< 96 h) mild-to-severe ARDS in 10 French centres. Patients were randomly assigned to receive three intravenous infusions of 106 UC-MSCs/kg or placebo (0.9% NaCl) over 5 days after recruitment. For the modified intention-to-treat population, the primary endpoint was the partial pressure of oxygen to fractional inspired oxygen (PaO2/FiO2)-ratio change between baseline (day (D) 0) and D7.

Results

Among the 107 patients screened for eligibility from April 6, 2020, to October 29, 2020, 45 were enrolled, randomized and analyzed. PaO2/FiO2 changes between D0 and D7 did not differ significantly between the UC-MSCs and placebo groups (medians [IQR] 54.3 [− 15.5 to 93.3] vs 25.3 [− 33.3 to 104.6], respectively; ANCOVA estimated treatment effect 7.4, 95% CI − 44.7 to 59.7; P = 0.77). Six (28.6%) of the 21 UC-MSCs recipients and six of 24 (25%) placebo-group patients experienced serious adverse events, none of which were related to UC-MSCs treatment.

Conclusions

D0-to-D7 PaO2/FiO2 changes for intravenous UC-MSCs-versus placebo-treated adults with SARS–CoV-2-induced ARDS did not differ significantly. Repeated UC-MSCs infusions were not associated with any serious adverse events during treatment or thereafter (until D28). Larger trials enrolling patients earlier during the course of their ARDS are needed to further assess UC-MSCs efficacy in this context.

Trial registration: NCT04333368. Registered 01 April 2020, https://clinicaltrials.gov/ct2/history/NCT04333368.

Stem cell therapy for COVID-19 pneumonia

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus is a highly contagious microorganism, and despite substantial investigation, no progress has been achieved in treating post-COVID complications. However, the virus has made various mutations and has spread around the world. Researchers have tried different treatments to reduce the side effects of the COVID-19 symptoms. One of the most common and effective treatments now used is steroid therapy to reduce the complications of this disease. Long-term steroid therapy for chronic inflammation following COVID-19 is harmful and increases the risk of secondary infection, and effective treatment remains challenging owing to fibrosis and severe inflammation and infection. Sometimes our immune system can severely damage ourselves in disease. In the past, many researchers have conducted various studies on the immunomodulatory properties of stem cells. This property of stem cells led them to modulate the immune system of autoimmune diseases like diabetes, multiple sclerosis, and Parkinson's. Because of their immunomodulatory properties, stem cell-based therapy employing mesenchymal or hematopoietic stem cells may be a viable alternative treatment option in some patients. By priming the immune system and providing cytokines, chemokines, and growth factors, stem cells can be employed to build a long-term regenerative and protective response. This review addresses the latest trends and rapid progress in stem cell treatment for Acute Respiratory Distress Syndrome (ARDS) following COVID-19.

SARS-CoV-2: Recent Variants and Clinical Efficacy of Antibody-Based Therapy

Multiple variants of SARS-CoV-2 have emerged and are now prevalent at the global level. Currently designated variants of concern (VOCs) are B.1.1.7, B1.351, P.1, B.1.617.2 variants and B.1.1.529. Possible options for VOC are urgently required as they carry mutations in the virus spike protein that allow them to spread more easily and cause more serious illness. The primary targets for most therapeutic methods against SARS-CoV-2 are the S (Spike) protein and RBD (Receptor-Binding Domain), which alter the binding to ACE2 (Angiotensin-Converting Enzyme 2). The most popular of these strategies involves the use of drug development targeting the RBD and the NTD (N-terminal domain) of the spike protein and multiple epitopes of the S protein. Various types of mutations have been observed in the RBDs of B.1.1.7, B1.351, P. and B.1.620. The incidence of RBD mutations increases the binding affinity to the ACE2 receptor. The high binding affinity of RBD and ACE2 has provided a structural basis for future evaluation of antibodies and drug development. Here we discuss the variants of SARS-CoV-2 and recent updates on the clinical evaluation of antibody-based treatment options. Presently, most of the antibody-based treatments have been effective in patients with SARS-CoV-2. However, there are still significant challenges in verifying independence, and the need for further clinical evaluation.

When stem cells meet COVID-19: recent advances, challenges and future perspectives

Coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory coronavirus 2 is currently spreading throughout the world with a high rate of infection and mortality and poses a huge threat to global public health. COVID-19 primarily manifests as hypoxic respiratory failure and acute respiratory distress syndrome, which can lead to multiple organ failure. Despite advances in the supportive care approaches, there is still a lack of clinically effective therapies, and there is an urgent need to develop novel strategies to fight this disease. Currently, stem cell therapy and stem cell-derived organoid models have received extensive attention as a new treatment and research method for COVID-19. Here, we discuss how stem cells play a role in the battle against COVID-19 and present a systematic review and prospective of the study on stem cell treatment and organoid models of COVID-19, which provides a reference for the effective control of the COVID-19 pandemic worldwide.

Advances in Targeting ACE2 for Developing COVID-19 Therapeutics

Since the onset of the coronavirus pandemic in December 2019, the SARS-CoV-2 virus has accounted for over 6.3 million lives resulting in the demand to develop novel therapeutic approaches to target and treat SARS-CoV-2. Improved understanding of viral entry and infection mechanisms has led to identifying different target receptors to mitigate infection in the host. Researchers have been working on identifying and targeting potential therapeutic target receptors utilizing different candidate drugs. Angiotensin-converting enzyme-2 (ACE2) has been known to perform critical functions in maintaining healthy cardiorespiratory function. However, ACE2 also functions as the binding site for the spike protein of SARS-CoV-2, allowing the virus to enter the cells and ensue infection. Therefore, drugs targeting ACE2 receptors can be considered as therapeutic candidates. Strategies targeting the level of ACE2 expression have been investigated and compared to other potential therapeutic targets, such as TMPRSS2, RdRp, and DPP4. This mini review discusses the key therapeutic approaches that target the ACE2 receptor, which is critical to the cellular entry and propagation of the novel SARS-CoV-2. In addition, we summarize the main advantages of ACE2 targeting against alternative approaches for the treatment of COVID-19.

Multipotent Stromal Cells and Viral Interaction: Current Implications for Therapy

Multipotent stromal cells (MSCs) are widely utilized in therapy for their immunomodulatory properties, but their usage in infectious viral diseases is less explored. This review aimed to collate the current novel use of MSCs in virus-associated conditions, including MSC's susceptibility to virus infection, antiviral properties of MSCs and their effects on cell-based immune response and implementation of MSC therapy in animal models and human clinical trials of viral diseases. Recent discoveries shed lights on MSC's capability in suppressing viral replication and augmenting clearance through enhancement of antiviral immunity. MSC therapy may maintain a crucial balance between aiding pathogen clearance and suppressing hyperactive immune response.

Mesenchymal stem/stromal cell-based therapies for severe viral pneumonia: therapeutic potential and challenges

Severe viral pneumonia is a significant cause of morbidity and mortality globally, whether due to outbreaks of endemic viruses, periodic viral epidemics, or the rarer but devastating global viral pandemics. While limited anti-viral therapies exist, there is a paucity of direct therapies to directly attenuate viral pneumonia-induced lung injury, and management therefore remains largely supportive. Mesenchymal stromal/stem cells (MSCs) are receiving considerable attention as a cytotherapeutic for viral pneumonia. Several properties of MSCs position them as a promising therapeutic strategy for viral pneumonia-induced lung injury as demonstrated in pre-clinical studies in relevant models. More recently, early phase clinical studies have demonstrated a reassuring safety profile of these cells. These investigations have taken on an added importance and urgency during the COVID-19 pandemic, with multiple trials in progress across the globe. In parallel with clinical translation, strategies are being investigated to enhance the therapeutic potential of these cells in vivo, with different MSC tissue sources, specific cellular products including cell-free options, and strategies to ‘licence’ or ‘pre-activate’ these cells, all being explored. This review will assess the therapeutic potential of MSC-based therapies for severe viral pneumonia. It will describe the aetiology and epidemiology of severe viral pneumonia, describe current therapeutic approaches, and examine the data suggesting therapeutic potential of MSCs for severe viral pneumonia in pre-clinical and clinical studies. The challenges and opportunities for MSC-based therapies will then be considered.