Biomarkers in acute respiratory distress syndrome: from pathobiology to improving patient care

Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by alveolar flooding with protein-rich pulmonary edema fluid. Despite an improved understanding of ARDS pathogenesis, our ability to predict the development of ARDS and risk-stratify patients with the disease remains limited. Biomarkers may help identify patients at highest risk of developing ARDS, assess response to therapy, predict outcome, and optimize enrollment in clinical trials. This review begins with a general description of biomarker use in clinical medicine. We then review evidence that supports the value of various ARDS biomarkers organized by the cellular injury processes central to ARDS development: endothelial injury, epithelial injury, disordered inflammation and coagulation, fibrosis, and apoptosis. Finally, we summarize the growing contributions of genomic and proteomic research and suggest ways in which the field may evolve in the coming years.