ABSTRACT
Background: Recently, the Rome classification was proposed in which objective and readily measurable variables were integrated to mark exacerbations of COPD (ECOPD) severity. The aim of this study is to investigate the distribution of a real-world patient population with hospitalised ECOPD according to the current classification across the newly proposed severity classification. We assume that a significant proportion of hospitalised patients will have a mild or moderate event. Methods: The Rome classification was applied to a cohort of 364 COPD patients hospitalised at the Department of Respiratory Medicine of Maastricht University Medical Center (MUMC) with a severe ECOPD. Differences in in-hospital, 30- and 90-day mortality were compared between mild, moderate and severe ECOPD according to the new classification. Moreover, data were stratified by the different severity classes and compared regarding general disease characteristics and clinical parameters. Results: According to the Rome proposal, 52 (14.3%) patients had a mild ECOPD, 204 (56.0%) a moderate and 108 (29.7%) a severe ECOPD. In-hospital mortality in mild, moderate and severe events was 3.8%, 6.9% and 13.9%, respectively. Most clinical parameters indicated a significantly worse condition in patients classified in the severe group, compared to those in mild or moderate groups. Conclusion: Most of the events, traditionally all classified as severe because of the hospitalisation, were classified as moderate, while almost 15% were mild. The results of this study provide insight into the heterogeneity of hospitalised ECOPD and show that the newly proposed Rome criteria can differentiate between events with different short-term mortality rates.
ABSTRACT
Cystic fibrosis (CF) lung disease is aggravated by recurrent and ultimately chronic bacterial infections. One of the key pathogens in adult CF lung disease is P. aeruginosa (PA). In addition to bacteria, respiratory viral infections are suggested to trigger pulmonary exacerbations in CF. To date, little is known on how chronic infections with PA influence susceptibility and response to viral infection. We investigated the interactions between PA, human rhinovirus (HRV) and the airway epithelium in a model of chronic PA infection using differentiated primary bronchial epithelial cells (pBECs) and clinical PA isolates obtained from the respiratory sample of a CF patient. Cells were repeatedly infected with either a mucoid or a non-mucoid PA isolate for 16 days to simulate chronic infection, and subsequently co-infected with HRV. Key cytokines and viral RNA were quantified by cytometric bead array, ELISA and qPCR. Proteolytic degradation of IL-6 was analyzed by Western Blots. Barrier function was assessed by permeability tests and transepithelial electric resistance measurements. Virus infection stimulated the production of inflammatory and antiviral mediators, including interleukin (IL)-6, CXCL-8, tumor necrosis factor (TNF)-α, and type I/III interferons. Co-infection with a non-mucoid PA isolate increased IL-1ß protein concentrations (28.88 pg/ml vs. 6.10 pg/ml), but in contrast drastically diminished levels of IL-6 protein (53.17 pg/ml vs. 2301.33 pg/ml) compared to virus infection alone. Conditioned medium obtained from co-infections with a non-mucoid PA isolate and HRV was able to rapidly degrade recombinant IL-6 in a serine protease-dependent manner, whereas medium from individual infections or co-infections with a mucoid isolate had no such effect. After co-infection with HRV and the non-mucoid PA isolate, we detected lower mRNA levels of Forkhead box J1 (FOXJ1) and Cilia Apical Structure Protein (SNTN), markers of epithelial cell differentiation to ciliated cells. Moreover, epithelial permeability was increased and barrier function compromised compared to single infections. These data show that PA infection can influence the response of bronchial epithelial cells to viral infection. Altered innate immune responses and compromised epithelial barrier function may contribute to an aggravated course of viral infection in PA-infected airways.
