Clinical course and prognosis in survivors of acute exacerbations of idiopathic pulmonary fibrosis

CSF3 aggravates acute exacerbation of pulmonary fibrosis by disrupting alveolar epithelial barrier integrity

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive respiratory disorder characterized by poor prognosis, often presenting with acute exacerbation. The primary cause of death associated with IPF is acute exacerbation of IPF (AE-IPF). However, the pathophysiology of acute exacerbation has not been clearly elucidated yet. This study aims to investigate the underlying pathophysiological molecular mechanism in a mouse AE-PF model. C57BL/6J mice were intratracheally administered bleomycin (BLM, 5 mg/kg) to induce pulmonary fibrosis. After 14 days, lipopolysaccharide (LPS, 2 mg/kg) was injected via the trachea route. Histological assessments, including H&E and Masson staining, as well as inflammatory indicators, were included to evaluate the induction of AE-PF by BLM and LPS in mice. Transcriptomic profiling of pulmonary tissues identified CSF3 as one of the top 10 upregulated DEGs in AE-PF mice. Indeed, administration of exogenous CSF3 protein exacerbated AE-PF in mice. Mechanistically, CSF3 disrupted alveolar epithelial barrier integrity and permeability by regulating specialized cell adhesion complexes such as tight junctions (TJs) and adherens junctions (AJs) via PI3K/p-Akt/Snail pathway, contributing to the aggravation of AE-PF in mice. Moreover, the discovery of elevated sera CSF3 indicated a notable increase in IPF patients during the exacerbation of the disease. Pearson correlation analysis in IPF patients revealed significant positive associations between CSF3 levels and KL-6 levels, LDH levels, CRP levels, respectively. These results provide mechanistic insights into the role of CSF3 in exacerbating of lung fibrotic disease and indicate monitoring CSF3 levels may aid in early clinical decisions for alternative therapy in the management of rapidly progressing IPF.

Prognostic value of the qSOFA in patients with acute exacerbation of idiopathic pulmonary fibrosis

BACKGROUND

Patients with idiopathic pulmonary fibrosis (IPF) have a slowly progressive clinical course, although some develop acute exacerbations (AEs). An easily obtained composite score is desirable for predicting the survival rate in patients with AE of IPF (AE-IPF). We investigated the quick sequential organ failure assessment (qSOFA), originally developed to identify sepsis, as a predictor of mortality in patients with AE-IPF and compared it to other composite assessments.

METHODS

Consecutive patients with IPF admitted for their first AE between 2008 and 2019 were recruited retrospectively. The association between the qSOFA score obtained at admission and mortality was investigated.

RESULTS

During the study period, 97 patients with AE-IPF were hospitalized. The hospital mortality was 30.9%. Multivariate logistic regression analysis revealed that both the qSOFA and the Japanese Association for Acute Medicine (JAAM)-disseminated intravascular coagulation (DIC) scores were significant predictors of hospital mortality (odds ratio [OR] 3.86, 95% confidence interval [CI] 1.43-10.3; p = 0.007 and OR 2.71, 95% CI 1.56-4.67; p = 0.0004; respectively). Kaplan-Meier survival curves showed that both scores were consistently associated with survival. Furthermore, the sum of the two scores was a more effective predictor than the individual scores.

CONCLUSIONS

The qSOFA score of patients admitted with AE-IPF was associated with both in-hospital and long-term mortality, which was also true for the JAAM-DIC score. The qSOFA score plus the JAAM-DIC score should be determined during the diagnostic evaluation of a patient with AE-IPF. Both scores combined may be more effective at predicting outcomes than individual scores.

Incidence and changes in treatment of acute exacerbation of idiopathic pulmonary fibrosis in Japan: A claims-based retrospective study

BACKGROUND

Acute exacerbation is an essential prognostic factor in idiopathic pulmonary fibrosis (IPF) and is the leading cause of death in Japanese patients with IPF. Its epidemiology, treatment status, and effect on IPF progression have been insufficiently investigated. We examined the incidence of acute exacerbation and treatment status before and after the onset of acute exacerbation in Japanese patients with IPF to provide basic information for treatment strategies.

METHODS

A Japanese claims database (April 2008-March 2019) from acute-care hospitals was analyzed. Incidence of acute exacerbation, time to the next event, and percentages of patients who received each treatment by the year before and after the onset of acute exacerbation were examined in patients diagnosed with IPF at least once. Acute exacerbation was defined according to the use of steroid pulse therapy.

RESULTS

We identified 9961 patients with IPF and 2629 acute exacerbations (average age at the time of acute exacerbation: 74.8 years, percentage of men: 79%). The annual incidence of acute exacerbation was approximately 10% between 2010 and 2018. The time to the next acute exacerbation shortened with increasing number of these events. The percentage of patients receiving antifibrotic drugs remained constant (30%-40%) throughout the period. The percentages of patients receiving steroid therapy, immunosuppressive drugs, and oxygen therapy increased after the onset of acute exacerbation compared with before the onset.

CONCLUSIONS

The annual incidence of acute exacerbation was approximately 10% in recent years. It is suggested that acute exacerbation worsens respiratory function in patients with IPF.