What does this research mean for the field?

Bronchoalveolar lavage fluid from tidal ventilation delays epithelial lung repair and promotes a fibroproliferative response via IL-6 pathway activation, which can be mitigated by pharmacological modulation of IL-6. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To analyze the impact of mechanical ventilation on lung repair mechanisms in epithelial and fibroblast cells.

May 20, 2026

A104-14 Proteomic Analysis of Tidal Ventilation and Cellular Transcriptomics Highlight Il6-associated Impaired Lung Repair

Key Points

To analyze the impact of mechanical ventilation on lung repair mechanisms in epithelial and fibroblast cells.
Collected bronchoalveolar lavage fluid from patients under protective mechanical ventilation and CPAP during cardiac surgery.
Compared proteomic profiles and performed wound healing assays on BEAS-2B and MRC5 cells supplemented with BALF samples.
Conducted RNA sequencing and targeted pharmacological modulation experiments to identify molecular mechanisms.
Identified 36 differentially expressed proteins, with fibrinogen components and thrombospondin-1 enriched under mechanical ventilation.
Epithelial cells showed slower wound closure rates and 154 differentially expressed genes under cyclic stretch, while fibroblasts exhibited an opposite pattern with 583 genes identified.
IL6 and TGFβ1 pathways were activated in lung cells, with tocilizumab selectively restoring wound closure in fibroblasts under MV.

Abstract

Abstract Introduction Mechanical ventilation (MV) is essential life support that ensures adequate alveolar ventilation and gas exchange in patients with respiratory failure. However, the application of high positive pressure and cyclic stretch applied can induce pathophysiological changes that not only exacerbate injury in lungs already affected by underlying disease but also cause damage in previously healthy lungs. These alterations trigger a complex molecular response that may lead to ineffective lung repair and fibrosis. Objective To study the impact of mechanical stretch associated with MV, identifying the different mechanisms involved in lung repair in epithelial and fibroblast cells. Methods Bronchoalveolar lavage fluid (BALF) was collected from patients under protective mechanical ventilation (MV, 6-8 ml/kg, PEEP 5 cmH2O) or continuous positive airway pressure (CPAP) of 5 cmH2O, during scheduled cardiac surgery. BALF proteomic profiles were compared between both ventilation conditions. Wound healing assays were performed in epithelial (BEAS-2B) and fibroblast (MRC5) cells supplemented with BALF samples. RNA sequencing was used to identify differentially expressed genes, molecular pathways and interactions associated with mechanical stretch. Targeted pharmacological modulation experiments were performed to evaluate the identified molecular mechanisms, and interaction analysis were applied to exclude the drug effects in MV condition. Results Proteomic analysis identified 36 differentially expressed proteins, with fibrinogen components (FGB, FGG) and thrombospondin-1 (THBS1) as key proteins enriched under MV condition. Cyclic stretch resulted in a slower wound closure rate in epithelial cells, compared to the static condition, accompanied by 154 differentially expressed genes, while fibroblasts exhibited an opposite behavior with 583 genes identified. Dysregulation of the interleukin-6 (IL6) and epidermal growth factor receptor (EGFR) gene pathways were observed in BEAS-2B cells, and changes in leukemia inhibitory factor (LIF), metalloproteinases (MMP1, MMP10), integrins (ITGA2, ITGA8, ITGB5, ITGB8), IL6 and transforming growth factor-beta 1 (TGFβ1) were detected in MRC5 cells. Treatment with tocilizumab selectively restored wound closure rates in fibroblast altered by MV BALF without affecting the CPAP condition, indicating a specific modulation of stretch-related pathways. In contrast, epithelial cells exhibited a non-specific response, as tocilizumab influenced wound healing under both conditions. Dissecting MV-specific molecular mechanisms, an interaction analysis highlighted upregulation of PPIA as a gene specifically associated with cyclic conditions and cellular stretching in epithelial cells. Conclusions BALF from tidal ventilation promotes a delay in epithelial-related lung repair and fibroproliferative response, through IL6 pathway activation and enhanced TGFβ1 expression. Modulation of stretch-induced expression of IL6 could promote effective tissue regeneration during mechanical ventilation. This abstract is funded by: None

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Cite This Study

Ramírez et al. (Fri,) studied this question.

synapsesocial.com/papers/6a0d4fa9f03e14405aa9b17c https://doi.org/https://doi.org/10.1093/ajrccm/aamag162.4665

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