Following severe traumatic brain injury, patients may remain unconscious for many years. It is the first proteomic analysis comparing differentially expressed proteins between patients with chronic disorder of consciousness and controls so far. The investigators generated accurate lists of proteomes and identified differences at different disease time courses. The obtained results provide new insight into understanding the molecular mechanisms underlying the chronic disorder of consciousness.

Background: Patients who awake from severely traumatic brain injury (sTBI) may remain unconscious for many years. Although behavioral assessment and functional imaging are currently used as diagnostic tools, the molecular basis underlying chronic condition has yet to be explored.

Objective:To explore the molecular basis and identify novel biomarkers for the diagnosis and prognosis of patients with chronic disorder of consciousness.

Method: Plasma samples were obtained from patients with chronic disorder of consciousness, and healthy volunteers. A coupled isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomics approach was used to screen differentially expressed proteins (DEPs) between patients and controls. Potential molecular mechanisms were further discussed through bioinformatics analyses. Candidate proteins were validated by enzyme-linked immunosorbent assay (ELISA).

Inclusion Criteria:

1. Patients ages 14 to 65 years old;
2. Patients had a history of sTBI;
3. Patients had awakened from a coma (indicating preserved sleep-wake cycles), including vegetative state and minimally consciousness state;
4. Patients stay unconscious for more than 1 month.

Exclusion Criteria:

1. Patients with acute infectious diseases or liver dysfunction;
2. Patients with serious diseases such as cardiac or pulmonary problems.

Patients with chronic disorder of consciousness were recruited at the rehabilitation units of Hangzhou Wujing Hospital (Hangzhou, Zhejiang, China).