Daily Ards Research Analysis
Two translational studies identify ferroptosis inhibition (KEAP1–NRF2–GPX4 axis) and C5a blockade as promising therapeutic strategies for ARDS, while a multicenter cohort suggests atracurium is as effective as cisatracurium for neuromuscular blockade. Together, these findings refine mechanistic targets and broaden pragmatic options at the bedside.
Summary
Two translational studies identify ferroptosis inhibition (KEAP1–NRF2–GPX4 axis) and C5a blockade as promising therapeutic strategies for ARDS, while a multicenter cohort suggests atracurium is as effective as cisatracurium for neuromuscular blockade. Together, these findings refine mechanistic targets and broaden pragmatic options at the bedside.
Research Themes
- Ferroptosis and oxidative injury pathways in ARDS
- Complement C5a-targeted immunotherapy
- Neuromuscular blockade strategy equivalence in ARDS
Selected Articles
1. Inhibition of ferroptosis by serine protease inhibitor attenuates acute respiratory distress syndrome.
Using LPS-induced murine ARDS and endothelial/epithelial cell models, ulinastatin reduced ferroptosis markers, suppressed KEAP1, activated NRF2, restored GPX4, and attenuated lung injury and inflammatory cytokines. Transcriptomics highlighted ferroptosis as a key pathway suppressed by UTI, suggesting a mechanistic link between UTI and KEAP1–NRF2–GPX4-mediated ferroptosis inhibition.
Impact: This work uncovers a novel anti-ferroptotic mechanism for an approved drug, providing a mechanistic rationale to repurpose ulinastatin for ARDS and to biomarker-enrich future trials.
Clinical Implications: While preclinical, the data support testing ulinastatin in ARDS populations with ferroptosis signatures and incorporating KEAP1–NRF2–GPX4 biomarkers to guide dosing and patient selection.
Key Findings
- UTI reduced labile iron, MDA, and lipid ROS and increased GPX4 expression in LPS-induced ARDS models.
- UTI suppressed KEAP1 and activated NRF2, consistent with ferroptosis inhibition.
- RNA-seq identified ferroptosis as a top pathway suppressed by UTI, correlating with reduced lung injury and cytokines.
Methodological Strengths
- Integrated in vivo and in vitro validation with transcriptomics and biochemical ferroptosis markers
- Mechanistic interrogation of KEAP1–NRF2–GPX4 axis including molecular docking
Limitations
- LPS-induced ARDS may not capture clinical heterogeneity of human ARDS
- Lack of genetic perturbation or biophysical binding confirmation to prove direct KEAP1 targeting
Future Directions: Validate KEAP1 binding biophysically and with genetic models; test efficacy in pneumonia/sepsis ARDS models; design biomarker-guided early-phase clinical trials.
BACKGROUND: Acute respiratory distress syndrome (ARDS), characterized by high mortality, involves multiple molecular programs, notably ferroptosis-a form of immunogenic cell death driven by iron overload and lipid peroxidation. Ulinastatin (UTI), a serine protease inhibitor, shows clinical efficacy in ARDS, but its underlying mechanism remains unclear. We aim to identify potential molecular targets in this process to promote clinical translation in ARDS treatment. METHODS: We performed RNA sequencing (RNA-seq) on lung tissues from LPS-induced ARDS mice revealed significant enrichment of ferroptosis-related pathways in UTI-treated ARDS mice, prompting the hypothesis that UTI mitigates ARDS by suppressing ferroptosis. Using LPS-induced murine ARDS, we assessed UTI's therapeutic effects via histopathology, qRT-PCR, RNA sequencing, and molecular assays. Ferroptosis biomarkers (iron, MDA, GSH), key proteins (GPX4, KEAP1, NRF2), and inflammatory cytokines were evaluated. In vitro, HUVEC and MLE-12 were used to investigate the molecular mechanisms by which UTI's functions via ferroptosis. Molecular docking explored UTI-KEAP1/NRF2 interactions. RESULTS: UTI significantly attenuated lung injury, reduced inflammatory cytokines (IL-1β, IL-6, TNF-α), and restored hepatic/renal function in LPS-challenged mice. Transcriptomics revealed ferroptosis as a top enriched pathway suppressed by UTI. Mechanistically, in both HUVEC and MLE-12 cells, UTI attenuated LPS-induced increases in labile iron, MDA, and lipid ROS levels. Additionally, UTI suppressed KEAP1 expression while activating NRF2, an effect comparable to that of ferroptosis inhibitors. Consequently, GPX4 expression was upregulated, suggesting a potential anti-ferroptotic mechanism. CONCLUSION: Inhibition of ferroptosis is a novel mechanism underpinning UTI's lung-protective effect against ARDS. UTI potentially regulates the KEAP1-NRF2 interaction through direct binding to KEAP1, offering a new molecular-level explanation for its mechanism of action.
2. Preclinical evaluation of STSA-1002, a novel human and rhesus monkeys cross-reactive monoclonal antibody targeting C5a, in acute respiratory distress syndrome models.
STSA-1002 bound human and rhesus C5a with high affinity, inhibited neutrophil responses in vitro, and reduced cytokines and mortality in LPS-induced ARDS models. Rhesus monkey pharmacokinetics showed linear exposure and 4-week repeat-dose toxicity supported a favorable safety profile.
Impact: Provides a comprehensive preclinical package for a cross-reactive anti-C5a antibody, enabling translational progression toward first-in-human studies in ARDS.
Clinical Implications: Supports complement-targeted immunotherapy development in ARDS; future trials could enrich for patients with complement activation and track C5a/IL-6 dynamics as pharmacodynamic biomarkers.
Key Findings
- High-affinity binding to human and rhesus C5a with functional inhibition of neutrophil degranulation, chemotaxis, and CD11b expression.
- Single-dose IV STSA-1002 reduced IL-6, TNF-α, IL-1β, GM-CSF, MCP-1 and mortality in an LPS-induced ARDS mouse model.
- Dose-dependent reductions in systemic and BALF cytokines with improved lung weight index; linear PK and favorable 4-week toxicity in rhesus monkeys.
Methodological Strengths
- Cross-species binding and functional assays enabling translational relevance
- Multiple in vivo models plus rhesus PK and repeat-dose toxicity evaluation
Limitations
- LPS-induced ARDS models may not recapitulate pathogen-driven clinical ARDS phenotypes
- Lack of ventilatory or gas-exchange endpoints and no human data yet
Future Directions: Test efficacy in pneumonia/sepsis ARDS models, evaluate combination with corticosteroids or anticoagulation, and initiate biomarker-enriched phase 1/2 studies.
BACKGROUND: The complement-activated product (C5a) is a key mediator in the pathogenesis of acute respiratory distress syndrome (ARDS). While blocking C5a represents a promising therapeutic strategy, novel anti-C5a therapies require further development. PURPOSE: This study aimed to develop a novel, human anti-C5a monoclonal antibody (STSA-1002) and evaluate its efficacy in treating ARDS through in vitro and vivo studies. RESULTS: In vitro, STSA-1002 exhibited high binding affinity to human and rhesus monkey C5a (EC50: 29.41 ± 10.74 ng/mL and 32.29 ± 10.96 ng/mL, respectively) and effectively inhibited C5a-induced neutrophil degranulation, chemotaxis, and CD11b expression. In vivo, single intravenous administration of STSA-1002 (1, 3 and 10 mg/kg) significantly reduced the levels of interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), granulocyte-macrophage colony stimulating factor (GM-CSF), monocyte chemotactic protein-1 (MCP-1) and mortality in a COVID-19-related LPS-induced ARDS mouse model (Model 1). In a second LPS-induced ARDS model (Model 2), STSA-1002 (1, 5 and 25 mg/kg) significantly reduced IL-6, TNF-α concentrations and leukocyte counts in serum and diminished IL-6 in bronchoalveolar lavage fluid (BALF), alongside improvements in lung weight index. In addition, pharmacokinetic (PK) studies in rhesus monkeys demonstrated linear exposure (5-50 mg/kg) and a favorable safety profile in a 4-week repeat-dose toxicity study. CONCLUSION: These results furnish comprehensive preclinical evidence for STSA-1002 as an innovative anti-C5a therapeutic agent and provide a preliminary rationale for developing immunomodulatory therapy in ARDS.
3. Two paths to paralysis: A multicenter comparison of cisatracurium to atracurium in the management of acute respiratory distress syndrome.
Across 384 ventilated patients with moderate-to-severe ARDS, atracurium and cisatracurium had similar ventilator-free days, 90-day mortality, length of stay, and ventilation duration after matching; cisatracurium produced greater oxygenation improvements without outcome differences.
Impact: Provides multicenter comparative effectiveness evidence supporting atracurium as a pragmatic alternative to cisatracurium when availability or cost is a concern.
Clinical Implications: Clinicians may select atracurium when cisatracurium is unavailable or costly without compromising major outcomes; definitive confirmation will require head-to-head randomized trials.
Key Findings
- No difference in 28-day ventilator-free days between atracurium and cisatracurium in unmatched or matched cohorts.
- No significant differences in 90-day inpatient mortality, hospital length of stay, or duration of mechanical ventilation after matching.
- Cisatracurium showed greater PaO2/FiO2 improvements, but this did not translate into better clinical outcomes.
Methodological Strengths
- Multicenter design with propensity score matching and multivariable analyses
- Clinically relevant endpoints including ventilator-free days and 90-day mortality
Limitations
- Retrospective design with potential for residual confounding
- Incomplete data on sedation practices and ventilator protocols that could influence outcomes
Future Directions: Conduct randomized non-inferiority trials comparing atracurium versus cisatracurium, include cost-effectiveness and long-term neuromuscular outcomes.
PURPOSE: Neuromuscular blocking agents (NMBAs) such as cisatracurium and atracurium are used to facilitate lung-protective ventilation in moderate-to-severe acute respiratory distress syndrome (ARDS). Although cisatracurium has been more extensively studied, data comparing these agents directly are limited. This study compares clinical outcomes between atracurium and cisatracurium in patients with moderate-to-severe ARDS. MATERIALS AND METHODS: This multicenter, retrospective cohort study was conducted between January 2017 and December 2023 across 11 Ascension Health hospitals. Mechanically ventilated adults with a PaO RESULTS: A total of 384 patients were included, with 192 in each group. Median 28-day ventilator-free days did not differ between groups in the unmatched (0 [IQR 0-16.7] vs. 0 [IQR 0-16.4], p = 0.72) or matched (0 [IQR 0-18.3] vs. 0 [IQR 0-14.4], p = 0.09) cohorts. These findings were further confirmed by multivariable analysis. After matching, there were no significant differences in 90-day inpatient mortality, length of stay, or duration of mechanical ventilation. While patients receiving cisatracurium showed greater improvements in PaO CONCLUSIONS: Atracurium and cisatracurium demonstrated similar safety and effectiveness in patients with moderate-to-severe ARDS. These results suggest that atracurium is a viable alternative to cisatracurium for the treatment of ARDS.