Summary of Wang, T. et al; Plasma neutrophil elastase and elafin as prognostic biomarker for acute respiratory distress syndrome: a multicenter survival and longitudinal prospective observation study. SHOCK Aug 2017. Click here for the full article.

Acute respiratory distress syndrome (ARDS) is a complicated clinical syndrome with a high mortality rate that is characterized by non-cardiogenic pulmonary edema and acute respiratory failure. In the lung an imbalance between the proteinases and their inhibitors damages the alveolar-capillary barrier, resulting in the leaking of protein-rich fluid into the interstitium and alveolar spaces, which is the key pathophysiological characteristic of ARDS. Previous studies have suggested that circulating elastase and elafin could be used to predict acute lung injury or ARDS development. However, whether they can be used as an early marker for the mortality and severity of ARDS is still unclear.

This study examines the association between neutrophil elastase and elafin with the mortality and severity of ARDS. A total of 167 ARDS patients were enrolled. Plasma samples were collected from each patient within the first day, third day and on the seventh day of ARDS development. Plasma elastase and elafin levels were assayed using an elafin ELISA kit (Cat. # HK318) and an elastase ELISA kit (Cat. # HK319). The results among the three time points demonstrated that elastase levels were significantly higher and elafin levels were significantly lower in non-survivors, indicating elastase as a risk factor and elafin as a protective factor for ARDS mortality. The markers combined also showed a better ARDS mortality prediction in comparison to the current prediction methods (APACHE II score and Berlin criteria). Based on these findings the paper concludes that circulation levels of elastase an elafin may have the potential to predict ARDS mortality and better inform clinicians about mortality risk.