Abstract Body (Do not enter title and authors here): Background: Adults born preterm are at an increased risk of hypertension and cardiopulmonary morbidities. However, little is known of the underlying mechanisms connecting neonatal hyperoxia (O₂) exposure to these long-term cardiopulmonary consequences in adults born preterm. Pro-inflammatory caspase-1 mediates the activation of cytokines IL-1β, and pore-forming protein Gasdermin-D.
Objective: To test the hypothesis that caspase-1 inhibition prevents long-term cardiopulmonary consequences of preterm birth.
Design/Methods: Newborn mice (n=60) exposed to normoxia (RA) or hyperoxia from postnatal day (P) 1 to 14 were randomly assigned to receive daily intraperitoneal (IP) injections of caspase-1 inhibitor (VX-765, 50 ug/Kg) or DMSO as placebo. The mouse pups recovered in RA into adulthood until 3 months of age. The effect of caspase-1 inhibition on Blood pressure (BP) by tail-cuff method, exercise endurance by treadmill testing, cardiac function by echocardiography, vascular stiffness by atomic force microscopy. The effect of caspase-1 inhibition on lung alveolarization, angiogenesis, pulmonary vascular remodeling was assessed by lung histology and immunostaining molecular and histological analysis were done at 3 months.

Results: Adult rats exposed to neonatal O₂ had significantly increased BP associated with vascular stiffness, reduced exercise capacity, cardiac hypertrophy, and cardiovascular inflammation. Caspase-1 inhibition prevented systemic vascular stiffness, hypertension, improved exercise tolerance (Fig 1A-B) as evidenced by treadmill speed and running time and decreased cardiac hypertrophy (Fig 1C) in adult mice exposed to neonatal O₂. Moreover, caspase -1 inhibition improved alveolar simplification, lung angiogenesis, pulmonary vascular remodeling and pulmonary hypertension in these mice (Fig 2A-C). Additionally, western blot analysis demonstrated that early supplementation of VX-765 in O₂ exposed mice led to reduced cardiac proinflammatory markers GSDMD and IL-1β in adulthood (Fig 3A-B).

Conclusion: Neonatal O₂ exposure predisposes to cardiopulmonary morbidities in adults born preterm. Inhibition of caspase-1 reduces cardiovascular inflammation and cardiopulmonary dysfunction in mice exposed to hyperoxia during the neonatal period. The functional and molecular impact of the use of caspase-1 suggests that it can be used as a novel preventive strategy for long-term cardiovascular dysfunction due to neonatal O₂ exposure in preterm survivors.