American journal of respiratory and critical care medicine
-
Am. J. Respir. Crit. Care Med. · Oct 2020
ReviewThe POOR Get POORer: A Hypothesis for the Pathogenesis of Ventilator-induced Lung Injury.
Protective ventilation strategies for the injured lung currently revolve around the use of low Vt, ostensibly to avoid volutrauma, together with positive end-expiratory pressure to increase the fraction of open lung and reduce atelectrauma. Protective ventilation is currently applied in a one-size-fits-all manner, and although this practical approach has reduced acute respiratory distress syndrome deaths, mortality is still high and improvements are at a standstill. Furthermore, how to minimize ventilator-induced lung injury (VILI) for any given lung remains controversial and poorly understood. ⋯ VILI progresses topographically outward from these regions in a POOR-get-POORer fashion unless steps are taken to interrupt it. We propose that interrupting the POOR-get-POORer progression of lung injury relies on two principles: 1) open the lung to minimize the presence of heterogeneity-induced stress concentrators that are focused around the regions of atelectasis, and 2) ventilate in a patient-dependent manner that minimizes the number of lung units that close during each expiration so that they are not forced to rerecruit during the subsequent inspiration. These principles appear to be borne out in both patient and animal studies in which expiration is terminated before derecruitment of lung units has enough time to occur.
-
Am. J. Respir. Crit. Care Med. · Oct 2020
Perinatal Hypoxia-Inducible Factor Stabilization Preserves Lung Alveolar and Vascular Growth in Experimental BPD.
Rationale: Antenatal inflammation with placental dysfunction is strongly associated with high bronchopulmonary dysplasia (BPD) risk in preterm infants. Whether antenatal or postnatal HIF (hypoxia-inducible factor) augmentation can preserve lung structure and function and prevent pulmonary hypertension after intrauterine inflammation is controversial. Objectives: To determine whether antenatal or postnatal prolyl-hydroxylase inhibitor (PHi) therapy increases lung HIF expression, preserves lung growth and function, and prevents pulmonary hypertension in a rat model of chorioamnionitis-induced BPD caused by antenatal inflammation. ⋯ Antenatal administration of PHi markedly upregulates lung HIF-1a, HIF-2a, VEGF, and eNOS expression after ETX exposure. Conclusions: HIF augmentation improves lung structure and function, prevents RVH, and improves placental structure following antenatal ETX exposure. We speculate that antenatal or postnatal PHi therapy may provide novel strategies to prevent BPD due to antenatal inflammation.
-
Am. J. Respir. Crit. Care Med. · Oct 2020
Comparative StudyRole of TL1A/DR3 Axis in the Activation of ILC2s in Eosinophilic Asthmatics.
Rationale: Group 2 innate lymphoid cells (ILC2s) are critical for type 2 inflammation. In murine models of asthma, some ILC2s remain activated in the absence of epithelial cell-derived cytokine signaling, implicating alternate stimulatory pathways. DR3 (death receptor 3), a member of the tumor necrosis factor receptor superfamily, is expressed on ILC2s. ⋯ The highest levels were detected in subjects with severe asthma with airway autoimmune responses. C1q+ immune complexes from the sputa of subjects with severe asthma with high autoantibody levels stimulated TL1A production by monocytes. Conclusions: The TL1A/DR3 axis is a costimulator of ILC2s in asthma, particularly in the airways of patients with a predisposition to autoimmune responses.