Serum Angiopoietin-2 level increase differs between polytraumatized patients with and without central nervous system injuries

Abstract

Since endothelial cells rapidly release Angiopoietin-2 (Ang-2) in response to vascular injury and inflammatory stimuli, we aimed to investigate if its serum levels increase in polytraumatized patients. Our cohort study evaluated 28 blunt polytrauma survivors (mean age, 38.4 years; median ISS, 34) who were directly admitted to our level I trauma center in 2018. We assessed the serum Ang-2 level at admission and on days 1, 3, 5, 7, and 10 during hospitalization. Ang-2 was released into the circulation immediately after polytrauma. At admission (day 0), it amounted to 8286 ± 5068 pg/mL, three-and-a-half times the reference value of 2337 ± 650 pg/mL assessed in a healthy control group. Subgroup analysis provided a higher mean Ang-2 level in the CNSI group combining all patients suffering a brain or spinal cord injury compared to the non-CNSI group solely on day 0 [11083 ± 5408 pg/mL versus 3963 ± 2062 pg/mL; p < 0.001]. Whereas the mean Ang-2 level increased only in the non-CNSI group from day 0 to day 3 (p = 0.009), the respective curves showed similar continuous decreases starting with day 3. Multivariate logistic regression analysis revealed an association between the Ang-2 day 0 level and the presence of a CNSI (OR = 1.885; p = 0.048). ROC analysis provided a cutoff level of 5352 pg/mL. In our study group, serum Ang-2 levels assessed at admission differed between polytraumatized patients with and without brain or spinal cord injuries. Based on our findings, we consider serum Ang-2 levels an effective biomarker candidate for indicating CNSI in these patients at admission, worthy of further evaluation in large multicenter studies.

Figure 1

Individual Ang-2 levels (grey lines) and mean Ang-2 level (bold black line) in the study group. The dotted and the two dashed parallel lines represent the mean, minimum, and maximum levels provided by healthy controls.

Figure 2

Mean Ang-2 levels in the CNSI-group (red line), comprising all individuals suffering injuries to the central nervous system and in the non-CNSI-group (black line), which combines all individuals without brain and spinal cord injuries. Error bars display SEM, * indicates a significant difference between the groups. The green line represents the mean value provided by healthy controls.

Figure 3

ROC curve of the serum Ang-2 level at admission and the presence of a CNSI in polytraumatized patients.