Low serum Kallistatin level was associated with poor neurological outcome of out-of-hospital cardiac arrest survivors: Proteomics study

To identify proteins of which depletion are associated with the poor 6-month neurological outcome of out-of-hospital cardiac arrest survivors. Seven healthy volunteers and 34 out-of-hospital cardiac arrest survivors admitted to the intensive care unit (ICU) and underwent targeted-temperature management were enrolled. According to the 6-month cerebral performance category (CPC) scale, patients were divided into the good (CPC 1–2) and poor (CPC 3–5) outcome groups. Blood samples were obtained at 0, 24, and 72 h after admission to the ICU. With proteomic approaches, we found 23 proteins that showed group-differences between the sera pooled from 7 study groups: healthy volunteers, the good outcome groups (0, 24, and 72 h), and the poor outcome groups (0, 24, and 72 h). We selected 7 candidate proteins of which intensities were different between the good and poor outcome groups (>2-fold change) and excluded 5 proteins related to haemolysis or remaining high abundant proteins. To confirm the 2 identified proteins: retinal dehydrogenase 1 and Kallistatin, we performed enzyme-linked immunosorbent assay with individual serum. Finally, old age (odds ratio = 1.055; 95% confidence interval, 1.002–1.112; p = 0.043) and low serum kallistatin level at 0 h (odds ratio = 0.784; 95% confidence interval, 0.618–0.995; p = 0.046) were independently associated with the poor 6-month neurological outcome. The depletion of serum kallistatin at admission to the ICU was associated with the poor neurological outcome of out-of-hospital cardiac arrest survivors.