Changes in neutrophil function in septic liver injury and its effect on prognosis: a prospective observational study / 中华危重病急救医学

ABSTRACT

To explore the changes in polymorphonuclear neutrophils (PMN) function in peripheral blood of patients with sepsis and liver injury and its prognostic value. Methods A prospective observational study was conducted. The patients who met the criteria of Sepsis-3 admitted to intensive care unit (ICU) of Wuxi People's Hospital Affiliated to Nanjing Medical University from March to August in 2019 were enrolled as the research objects, and the patients were divided into sepsis without liver injury group and sepsis with liver injury group; non-sepsis patients who were hospitalized at the same time were enrolled as non-sepsis group; and the healthy people in the physical examination center were enrolled as healthy control group. The gender, age, white blood cell (WBC), PMN and procalcitonin (PCT) were recorded when the patients were admitted to ICU as well as the people on the day of physical examination. The acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and sequential organ failure assessment (SOFA) scores were calculated. The 28-day mortality was recorded. The quantitative level of neutrophil extracellular traps (NETs) which reflected by circulating free DNA (cf-DNA/NETs) in peripheral plasma was determined by PicoGreen fluorescence quantitative detection; the qualitative level of NETs was detected by immunofluorescence staining. PMN was extracted from the healthy control group, sepsis without liver injury group and sepsis with liver injury group and cultured in vitro, the quantitative level of cf-DNA/NETs in cell supernatant was determined by PicoGreen fluorescence quantitative detection. The patients were divided into two groups according to 28-day outcome of sepsis patients with liver injury. Receiver operating characteristic (ROC) curve was plotted, and the area under ROC curve (AUC) was calculated to analyze the prognostic value of NETs in sepsis patients with liver injury. Results Finally, 21 sepsis patients without liver injury, 15 sepsis patients with liver injury, 20 with non-sepsis and 20 with healthy examination were enrolled. There was no significant difference in gender or age among the four groups, indicating that the patients in each group were comparable. The levels of cf-DNA/NETs in peripheral blood, WBC and PMN of the sepsis with and without liver injury groups were significantly higher than those of the healthy control group and non-sepsis group, PCT, APACHE Ⅱ score, SOFA score and 28-day mortality were significantly higher than those of the non-sepsis group, and the levels of cf-DNA/NETs in peripheral blood, PCT and 28-day mortality of the sepsis with liver injury group were significantly higher than those of the sepsis without liver injury group [cf-DNA/NETs (μg/L) 481.60±275.86 vs. 169.76±57.05, PCT (μg/L) 11.29 (1.79, 67.10) vs. 1.11 (0.19, 4.09), 28-day mortality 73.3% (11/15) vs. 38.1% (8/21), all P < 0.05]. The results of PMN in vitro showed that there was no NETs in normal culture of healthy control group, and a small amount of NETs was detected in sepsis with and without liver injury groups. After stimulation of PMN stimulator phorbol-12-myristate-13-acetic acid (PMA), more NETs were produced in neutrophils of three groups compared with normal culture. Quantitative analysis showed that the level of cf-DNA/NETs in cell supernatant of the sepsis with liver injury group was significantly higher than that of the sepsis without liver injury group (μg/L 1 872.29±258.44 vs. 1 313.55±147.45, P < 0.01). In 15 sepsis patients with liver injury, 4 patients survived for 28 days (26.7%) and 11 died (73.3%). The cf-DNA/NETs level of the dead group on the day of admission was significantly higher than that of the survival group (μg/L 582.36±160.05 vs. 241.17±96.14, P < 0.05). ROC curve analysis showed that the AUC of NETs level in peripheral blood for predicting 28-day death of sepsis patients with liver injury was 0.932 [95% confidence interval (95%CI) was 0.787-1.000]; when the best cut-off value was 266.81 μg/L, the sensitivity was 90.9%, the specificity was 75.0%, and the approximate index was 0.659. Conclusions The function of NETs in sepsis patients with liver injury has been further changed. The level of peripheral blood NETs has a certain guiding value for the prognosis of sepsis patients with liver injury.