C107-02 Ventilation-induced Lung Injury in P16-ink Attac Aged Mice

Abstract Rationale Mechanical ventilation (MV), while lifesaving, can cause primary injury to the lungs known as ventilation-induced lung injury (VILI), which may trigger systemic inflammation and impair recovery. Cellular senescence, a process where cells permanently lose the ability to divide yet remain metabolically active, has emerged as a key contributor to chronic inflammation and tissue dysfunction. Senescent cells accumulate with age and release inflammatory mediators through the senescence-associated secretory phenotype (SASP), including cytokines, that mirror the pathways activated during VILI. The p16Ink4a pathway, a marker of senescence, has been implicated in age-related pulmonary injury and impaired repair mechanisms. Despite these overlaps, the contribution of senescent cells to VILI pathogenesis remains underexplored. This study investigates whether the presence of senescent cells exacerbates lung injury and inflammation during MV and whether pharmacologic clearance of these cells can mitigate VILI in aged mice. Methods The experimental methods were conducted using 11 to 15-month-old male and female mice randomly separated into three subject groups: (1) p16-INK-ATTAC C57BL/6 mice, which serve as a model for cellular senescence; (2) p16-INK-ATTAC mice treated with AP20187 to induce selective deletion of p16-positive cells; and (3) wild-type C57BL/6 controls. Mice from each group were sedated with a ketamine/xylazine solution (90 µg/mL ketamine and 20 µg/mL xylazine), intubated intratracheally, and mechanically ventilated for 2 hours on high-pressure settings of 35 cmH2O to stimulate lung injury. Mechanical scans were performed every 30 minutes. Blood from the vena cava was retrieved, perfusion through the left ventricle of the heart and brain, bronchoalveolar lavage fluid (BALF), and lung collections were performed immediately after the final time point. The control group did not receive mechanical ventilation, and samples were collected directly after sedation. Plasma was extracted from the blood sample. Cells were separated from the BALF collection, counted, fixed using cytospinning, and then stained using a Hemacolor stain set. DuoSet ELISAs were performed on the remaining BALF samples. Results p16-INK-ATTAC mice treated with AP20187 showed increased lung compliance and reduced elastance compared to non-dosed and wild-type mice following mechanical ventilation. AP20187 treatment also improved hysteresis and inspiratory capacity. These improvements were accompanied by normalized cell counts and reduced IL-6 levels, indicating decreased inflammation and better preservation of alveolar architecture on histological analysis. Conclusions Selective clearance of p16-positive cells improved lung mechanics and reduced inflammation, indicating that targeting cellular senescence may protect against ventilation-induced lung injury. This abstract is funded by: None