Cell-based therapies for acute respiratory distress syndrome

Pathophysiological mechanisms of ARDS: a narrative review from molecular to organ-level perspectives

BACKGROUND

Acute respiratory distress syndrome (ARDS) remains a life-threatening pulmonary condition with persistently high mortality rates despite significant advancements in supportive care. Its complex pathophysiology involves an intricate interplay of molecular and cellular processes, including cytokine storms, oxidative stress, programmed cell death, and disruption of the alveolar-capillary barrier. These mechanisms drive localized lung injury and contribute to systemic inflammatory response syndrome and multiple organ dysfunction syndrome. Unlike prior reviews that primarily focus on isolated mechanisms, this narrative review synthesizes the key pathophysiological processes of ARDS across molecular, cellular, tissue, and organ levels.

MAIN BODY

By integrating classical theories with recent research advancements, we provide a comprehensive analysis of how inflammatory mediators, metabolic reprogramming, oxidative stress, and immune dysregulation synergistically drive ARDS onset and progression. Furthermore, we critically evaluate current evidence-based therapeutic strategies, such as lung-protective ventilation and prone positioning, while exploring innovative therapies, including stem cell therapy, gene therapy, and immunotherapy. We emphasize the significance of ARDS subtypes and their inherent heterogeneity in guiding the development of personalized treatment strategies.

CONCLUSIONS

This narrative review provides fresh perspectives for future research, ultimately enhancing patient outcomes and optimizing management approaches in ARDS.

Isoliquiritigenin Exhibits Anti-Inflammatory Responses in Acute Lung Injury by Covalently Binding to the Myeloid Differentiation Protein-2 Domain

Acute lung injury (ALI), a systemic inflammatory response with high morbidity, lacks effective pharmacological therapies. Myeloid differentiation protein-2 (MD2) has emerged as a promising therapeutic target for ALI. Herein, we aimed to evaluate the ability of isoliquiritigenin (ISL), a natural flavonoid found in licorice as a novel MD2 inhibitor, to inhibit lipopolysaccharide (LPS)-induced ALI. We established a mouse ALI model and a RAW 264.7 cell injury model through LPS administration. Then, lung injury was assessed through histopathological examination, and the effects of ISL were evaluated using immunofluorescence, western blotting, reverse transcription-quantitative polymerase chain reaction, flow cytometry, and enzyme-linked immunosorbent assays. In addition, the interaction between ISL and MD2 was investigated through co-immunoprecipitation and LPS displacement assays. Molecular docking and liquid chromatography/mass spectrometry analyses were employed to predict the ISL-binding domain of MD2. We found that ISL covalently bound to the Cysteine 133 residue of MD2, disrupting the formation of the LPS/MD2/toll-like receptor 4 complex, and ISL significantly suppressed proinflammatory cytokine production and reactive oxygen species generation in LPS-induced RAW264.7 cells. Moreover, ISL significantly alleviated lung injury in LPS-induced mice, reducing pulmonary microvascular permeability, inflammatory cell infiltration, and inflammatory cytokine expression. The underlying mechanism of ISL involved the inhibition of nuclear factor kappa B and the p38 mitogen-activated protein kinase pathway. Our findings supported that MD2 is the direct target of ISL in mediating its anti-inflammatory response in vivo and in vitro, and it holds potential as a therapeutic candidate for treating ALI and other inflammatory diseases.

Progress in cytokine research for ARDS: A comprehensive review

Introduction

Acute respiratory distress syndrome (ARDS) is a critical form of acute respiratory failure characterized by diffuse alveolar damage, refractory hypoxemia, and non-cardiogenic pulmonary edema, resulting in high mortality. Dysregulated inflammation, driven by cytokines, is central to ARDS pathogenesis, progression, and prognosis.

Objective

This review synthesizes current knowledge on the role of cytokines in ARDS and evaluates their potential as therapeutic targets, offering new insights for clinical management.

Methods

A comprehensive analysis of recent studies was conducted to explore the roles of pro-inflammatory cytokines (e.g., IL-1β, IL-6, IL-8) and anti-inflammatory cytokines (e.g., IL-10, IL-22) in ARDS pathogenesis and to assess current and emerging therapies targeting these cytokines.

Results

Pro-inflammatory cytokines are crucial in initiating inflammatory responses and lung injury in early ARDS, while anti-inflammatory cytokines help regulate and resolve inflammation. Targeted therapies, such as IL-1 and IL-6 inhibitors, show potential in managing ARDS, particularly in COVID-19, but their clinical efficacy is still debated. Combination therapy strategies may enhance outcomes, but further large-scale, multicenter randomized controlled trials are required to establish their safety and efficacy.

Conclusion

Understanding cytokine regulation in ARDS could lead to innovative therapeutic approaches. Future research should focus on cytokine roles across ARDS subtypes and stages and develop biomarker-driven, individualized treatments.

Therapeutic Benefits of Mesenchymal Stem Cells in Acute Respiratory Distress Syndrome: Potential Mechanisms and Challenges

Acute respiratory distress syndrome (ARDS) presents as a form of acute respiratory failure resulting from non-cardiogenic pulmonary edema due to excessive alveolocapillary permeability, which may be pulmonary or systemic in origin. In the last 3 years, the coronavirus disease 2019 pandemic has resulted in an increase in ARDS cases and highlighted the challenges associated with this syndrome, as well as the unacceptably high mortality rates and lack of effective treatments. Currently, clinical treatment remains primarily supportive, including mechanical ventilation and drug-based therapy. Mesenchymal stem cell (MSC) therapies are emerging as a promising intervention in patients with ARDS and have promising therapeutic effects and safety. The therapeutic mechanisms include modifying the immune response and assisting with tissue repair. This review provides an overview of the general properties of MSCs and outlines their role in mitigating lung injury and promoting tissue repair in ARDS. Finally, we summarize the current challenges in the study of translational MSC research and identify avenues by which the discipline may progress in the coming years.

Catching Them Early: Framework Parameters and Progress for Prenatal and Childhood Application of Advanced Therapies

Advanced therapy medicinal products (ATMPs) are medicines for human use based on genes, cells or tissue engineering. After clear successes in adults, the nascent technology now sees increasing pediatric application. For many still untreatable disorders with pre- or perinatal onset, timely intervention is simply indispensable; thus, prenatal and pediatric applications of ATMPs hold great promise for curative treatments. Moreover, for most inherited disorders, early ATMP application may substantially improve efficiency, economy and accessibility compared with application in adults. Vindicating this notion, initial data for cell-based ATMPs show better cell yields, success rates and corrections of disease parameters for younger patients, in addition to reduced overall cell and vector requirements, illustrating that early application may resolve key obstacles to the widespread application of ATMPs for inherited disorders. Here, we provide a selective review of the latest ATMP developments for prenatal, perinatal and pediatric use, with special emphasis on its comparison with ATMPs for adults. Taken together, we provide a perspective on the enormous potential and key framework parameters of clinical prenatal and pediatric ATMP application.

Translating Basic Research into Safe and Effective Cell-based Treatments for Respiratory Diseases

Respiratory diseases, such as chronic obstructive pulmonary disease and pulmonary fibrosis, result in severely impaired quality of life and impose significant burdens on healthcare systems worldwide. Current disease management involves pharmacologic interventions, oxygen administration, reduction of infections, and lung transplantation in advanced disease stages. An increasing understanding of mechanisms of respiratory epithelial and pulmonary vascular endothelial maintenance and repair and the underlying stem/progenitor cell populations, including but not limited to airway basal cells and type II alveolar epithelial cells, has opened the possibility of cell replacement-based regenerative approaches for treatment of lung diseases. Further potential for personalized therapies, including in vitro drug screening, has been underscored by the recent derivation of various lung epithelial, endothelial, and immune cell types from human induced pluripotent stem cells. In parallel, immunomodulatory treatments using allogeneic or autologous mesenchymal stromal cells have shown a good safety profile in clinical investigations for acute inflammatory conditions, such as acute respiratory distress syndrome and septic shock. However, as yet, no cell-based therapy has been shown to be both safe and effective for any lung disease. Despite the investigational status of cell-based interventions for lung diseases, businesses that market unproven, unlicensed and potentially harmful cell-based interventions for respiratory diseases have proliferated in the United States and worldwide. The current status of various cell-based regenerative approaches for lung disease as well as the effect of the regulatory environment on clinical translation of such approaches are presented and critically discussed in this review.

Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases 2017. An Official American Thoracic Society Workshop Report

The University of Vermont Larner College of Medicine, in collaboration with the National Heart, Lung, and Blood Institute (NHLBI), the Alpha-1 Foundation, the American Thoracic Society, the Cystic Fibrosis Foundation, the European Respiratory Society, the International Society for Cell & Gene Therapy, and the Pulmonary Fibrosis Foundation, convened a workshop titled "Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases" from July 24 through 27, 2017, at the University of Vermont, Burlington, Vermont. The conference objectives were to review and discuss current understanding of the following topics: 1) stem and progenitor cell biology and the role that they play in endogenous repair or as cell therapies after lung injury, 2) the emerging role of extracellular vesicles as potential therapies, 3) ex vivo bioengineering of lung and airway tissue, and 4) progress in induced pluripotent stem cell protocols for deriving lung cell types and applications in disease modeling. All of these topics are research areas in which significant and exciting progress has been made over the past few years. In addition, issues surrounding the ethics and regulation of cell therapies worldwide were discussed, with a special emphasis on combating the growing problem of unproven cell interventions being administered to patients with lung diseases. Finally, future research directions were discussed, and opportunities for both basic and translational research were identified.

The Necrobiology of Mesenchymal Stromal Cells Affects Therapeutic Efficacy

Rapid progress is occurring in understanding the mechanisms underlying mesenchymal stromal cell (MSC)-based cell therapies (MSCT). However, the results of clinical trials, while demonstrating safety, have been varied in regard to efficacy. Recent data from different groups have shown profound and significant influences of the host inflammatory environment on MSCs delivered systemically or through organ-specific routes, for example intratracheal, with subsequent actions on potential MSC efficacies. Intriguingly in some models, it appears that dead or dying cells or subcellular particles derived from them, may contribute to therapeutic efficacy, at least in some circumstances. Thus, the broad cellular changes that accompany MSC death, autophagy, pre-apoptotic function, or indeed the host response to these processes may be essential to therapeutic efficacy. In this review, we summarize the existing literature concerning the necrobiology of MSCs and the available evidence that MSCs undergo autophagy, apoptosis, transfer mitochondria, or release subcellular particles with effector function in pathologic or inflammatory in vivo environments. Advances in understanding the role of immune effector cells in cell therapy, especially macrophages, suggest that the reprogramming of immunity associated with MSCT has a weighty influence on therapeutic efficacy. If correct, these data suggest novel approaches to enhancing the beneficial actions of MSCs that will vary with the inflammatory nature of different disease targets and may influence the choice between autologous or allogeneic or even xenogeneic cells as therapeutics.