Proteomic Profiles in Acute Respiratory Distress Syndrome Differentiates Survivors from Non-Survivors

Abstract

Acute Respiratory Distress Syndrome (ARDS) continues to have a high mortality. Currently, there are no biomarkers that provide reliable prognostic information to guide clinical management or stratify risk among clinical trial participants. The objective of this study was to probe the bronchoalveolar lavage fluid (BALF) proteome to identify proteins that differentiate survivors from non-survivors of ARDS. Patients were divided into early-phase (1 to 7 days) and late-phase (8 to 35 days) groups based on time after initiation of mechanical ventilation for ARDS (Day 1). Isobaric tags for absolute and relative quantitation (iTRAQ) with LC MS/MS was performed on pooled BALF enriched for medium and low abundance proteins from early-phase survivors (n = 7), early-phase non-survivors (n = 8), and late-phase survivors (n = 7). Of the 724 proteins identified at a global false discovery rate of 1%, quantitative information was available for 499. In early-phase ARDS, proteins more abundant in survivors mapped to ontologies indicating a coordinated compensatory response to injury and stress. These included coagulation and fibrinolysis; immune system activation; and cation and iron homeostasis. Proteins more abundant in early-phase non-survivors participate in carbohydrate catabolism and collagen synthesis, with no activation of compensatory responses. The compensatory immune activation and ion homeostatic response seen in early-phase survivors transitioned to cell migration and actin filament based processes in late-phase survivors, revealing dynamic changes in the BALF proteome as the lung heals. Early phase proteins differentiating survivors from non-survivors are candidate biomarkers for predicting survival in ARDS.

Biomarkers for the acute respiratory distress syndrome: how to make the diagnosis more precise

“…While most studies have targeted a pre-determined biomarker, several investigators have examined proteomic changes in BALF samples from ARDS patients using a non-targeted approach (64)(65)(66). These non-targeted proteomic studies compared the protein levels in the BALF or undiluted pulmonary edema fluid in ARDS patients and in healthy controls.…”

“…Ideally, BALF proteomics could be useful for the molecular profiling of DAD. For example, Bhargava et al (66) examined BALF from patients with different severities of lung injury, and identified 792 proteins, from which 161 were differentially expressed in survivors and non survivors in the early phase of ARDS. Pathways related to activation of immune response, wound healing and coagulation were predominant in survivors, while pathways of collagen synthesis and carbohydrate catabolism were more abundant in non-survivors.…”

Proteome Profiling in Lung Injury after Hematopoietic Stem Cell Transplantation

“…Graft sources included bone marrow (1), peripheral blood stem cells (6), umbilical cord blood (18) and natural killer cell (3). All BALF samples were collected from clinically indicated bronchoscopies performed using a standard protocol [18, 19] with excess, cell-free supernatant used for these studies. The diagnosis of IPS or infectious lung injury was made using the criteria established by the American Thoracic Society [6] (Table 2).…”

“…BALF samples containing at least 1.2 mg of proteins were processed for LC-MS/MS from individual patients employing a protocol previously published with minor modifications [18]. BALF was concentrated and desalted using Amicon 3-MWCO filters.…”

“…Hemoglobin depletion was performed with Hemoglobind (BioTech Support Group LLC, Monmouth Junction, NJ) per the manufacturer's instructions. Subsequent processing was similar to our prior study with immunoaffinity depletion of high abundance proteins to reduce the dynamic range and appropriate buffer exchanges for labeling with iTRAQ reagent [18]. …”