RESUMEN

Background: Bronchopulmonary dysplasia (BPD) is one of the most common and severe chronic diseases in preterm infants. Premature infants are susceptible to BPD due to immature lungs and adverse perinatal episodes of infection, hyperoxia, and mechanical ventilation. Methods: Neutrophils are the first line of host defence, and the release of neutrophil extracellular traps (NETs) is an important strategy to immobilize and kill invading microorganisms. This study examined whether NETs were associated with BPD in preterm infants and contributed to hyperoxia-induced lung injury in neonatal mice via the WNT/ß-catenin pathway. Results: In this study, we found that preterm infants with BPD had higher levels of NETs in their tracheal aspirates than those without BPD. Neonatal mice treated with NETs after birth exhibited BPD-like changes in their lungs. Furthermore, the levels of Aquaporin 5 (AQP5) and surfactant-associated protein C (SPC), which represent alveolar differentiation and development, were significantly lower than those in the controls. The WNT/ß-catenin pathway is one of the most well-known signalling pathways involved in lung growth. We found that the expression of the target genes c-MYC, cyclin D, and vascular endothelial growth factor (VEGF) and the important proteins WNT3a and ß-catenin significantly decreased. Moreover, heparin, which is a NET inhibitor, attenuated changes in gene and protein expression, thereby attenuating BPD-like changes. Discussion: This finding indicates that NETs are associated with BPD and can induce BPD-like changes in neonatal mice via the WNT/ß-catenin pathway.

Asunto(s)

Displasia Broncopulmonar , Trampas Extracelulares , Hiperoxia , Recién Nacido , Humanos , Embarazo , Femenino , Animales , Ratones , Displasia Broncopulmonar/metabolismo , Animales Recién Nacidos , Hiperoxia/metabolismo , Trampas Extracelulares/metabolismo , beta Catenina/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Recien Nacido Prematuro , Pulmón/metabolismo , Vía de Señalización Wnt

RESUMEN

Many indoor places, including aged classrooms and offices, prisons, homeless shelters, etc., are poorly ventilated but resource-limited to afford expensive ventilation upgrades or commercial air purification systems, raising concerns on the safety of opening activities in these places in the era of the COVID-19 pandemic. To address this challenge, using computational fluid dynamics, we conducted a systematic investigation of airborne transmission in a classroom equipped with a single horizontal unit ventilator (HUV) and evaluate the performance of a low-cost box fan air cleaner for risk mitigation. Our study shows that placing box fan air cleaners in the classroom results in a substantial reduction of airborne transmission risk across the entire space. The air cleaner can achieve optimal performance when placed near the asymptomatic patient. However, without knowing the location of the patient, the performance of the cleaner is optimal near the HUV with the air flowing downwards. In addition, we find that it is more efficient in reducing aerosol concentration and spread in the classroom by adding air cleaners in comparison with raising the flow rate of HUV alone. The number and placement of air cleaners need to be adjusted to maintain their efficacy for larger classrooms and to account for the thermal gradient associated with a human thermal plume and hot ventilation air during cold seasons. Overall, our study shows that box fan air cleaners can serve as an effective low-cost alternative for mitigating airborne transmission risks in poorly ventilated spaces.