Determination of desmosine in bronchoalveolar lavage fluids by time-resolved fluoroimmunoassay

Syndrome of Combined Pulmonary Fibrosis and Emphysema: An Official ATS/ERS/JRS/ALAT Research Statement

Background: The presence of emphysema is relatively common in patients with fibrotic interstitial lung disease. This has been designated combined pulmonary fibrosis and emphysema (CPFE). The lack of consensus over definitions and diagnostic criteria has limited CPFE research. Goals: The objectives of this task force were to review the terminology, definition, characteristics, pathophysiology, and research priorities of CPFE and to explore whether CPFE is a syndrome. Methods: This research statement was developed by a committee including 19 pulmonologists, 5 radiologists, 3 pathologists, 2 methodologists, and 2 patient representatives. The final document was supported by a focused systematic review that identified and summarized all recent publications related to CPFE. Results: This task force identified that patients with CPFE are predominantly male, with a history of smoking, severe dyspnea, relatively preserved airflow rates and lung volumes on spirometry, severely impaired DlCO, exertional hypoxemia, frequent pulmonary hypertension, and a dismal prognosis. The committee proposes to identify CPFE as a syndrome, given the clustering of pulmonary fibrosis and emphysema, shared pathogenetic pathways, unique considerations related to disease progression, increased risk of complications (pulmonary hypertension, lung cancer, and/or mortality), and implications for clinical trial design. There are varying features of interstitial lung disease and emphysema in CPFE. The committee offers a research definition and classification criteria and proposes that studies on CPFE include a comprehensive description of radiologic and, when available, pathological patterns, including some recently described patterns such as smoking-related interstitial fibrosis. Conclusions: This statement delineates the syndrome of CPFE and highlights research priorities.

Increased circulating desmosine and age-dependent elastinolysis in idiopathic pulmonary fibrosis

Although chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) seem to be opposite entities from a clinical perspective, common initial pathogenic steps have been suggested in both lung diseases. Emphysema is caused by an elastase/anti-elastase imbalance leading to accelerated elastin degradation. Elastinolysis is however, also accelerated in the IPF patients’ lungs. The amino acids desmosine and isodesmosine (DES) are unique to elastin. During the degradation process, elastases liberate DES from elastin fibers. Blood DES levels consequently reflect the rate of systemic elastinolysis and are increased in COPD. This is the first report describing elevated DES levels in IPF patients. We also demonstrated that the age-related increment of DES concentrations is enhanced in IPF. Our current study suggests that elastinolysis is a shared pathogenic step in both COPD and IPF. Further investigation is required to establish the relevance of accelerated elastin degradation in IPF and to determine whether decelerating this process leads to slower progression of lung fibrosis and better survival for patients with IPF.

Elastases from inflammatory and dendritic cells mediate ultrafine carbon black induced acute lung destruction in mice

CONTEXT

Exposure to ultrafine particles (<100 nm in diameter) is postulated to cause chronic obstructive pulmonary disease (COPD). However, the mechanism remains to be elucidated.

OBJECTIVE

We aimed to evaluate whether ultrafine particle exposure causes the infiltration of inflammatory and dendritic cells (DCs) with increased elastase activity, contributing to lung parenchymal destruction.

MATERIALS AND METHODS

C57BL/6 male mice were intratracheally instilled with 300 µg ultrafine carbon black (ufCB; 14 nm in diameter), and sacrificed at 1, 3, 7 and 14 d post-exposure. Differential cell counts, elastase activities, and desmosine and hydroxyproline in bronchoalveolar (BAL) fluid were determined. Immunofluorescent staining and flow cytometry analysis determined the cell origin of macrophage metalloelastase (MMP-12). Anti-neutrophil antibody was applied to assess the contribution of elastase in ufCB induced lung destruction.

RESULTS

ufCB exposure led to significant increases in neutrophils, mononuclear cells and total proteins in BAL fluid. Desmosine and hydroxyproline were significantly increased in the ufCB group. Elastase activities were found to be significantly elevated, with both neutrophil elastase and MMP-12 peaking at 3 d post-exposure. Flow cytometry analysis demonstrated that pulmonary infiltrations of MMP-12 positive DCs, including Langerhans cells-derived DCs, occurred at 3 d and 7 d, while macrophage infiltration was obvious starting at 1 d. Anti-neutrophil antibody significantly reduced neutrophil elastase activity and prevented the increases in BAL desmosine and hydroxyproline following ufCB exposure.

CONCLUSION

For the first time we demonstrate the infiltration of Langerhans and myeloid dendritic cells, and show that elastase production contributes to pulmonary destruction following exposure to ultrafine particles.