Effects of hemoadsorption on cytokine removal and short-term survival in septic rats

Abstract

Objective: A broad-spectrum immune-regulating therapy could be beneficial in the treatment of sepsis. Our previous studies have shown that a hemoadsorption device (CytoSorb) removes both pro- and anti-inflammatory cytokines and improves survival in experimental endotoxemia. We sought to determine whether hemoadsorption can also be effective in the treatment of sepsis.

Design: Randomized controlled laboratory experiment.

Setting: University laboratory.

Interventions: Rats were subjected to cecal ligation and puncture (CLP) and 20 hrs later were randomized to receive either hemoadsorption or sham treatment using an arterial-venous circuit. Hemoadsorption was accomplished using a cartridge containing Cytosorb beads. Blood was drawn for cytokine measurements and mean arterial pressure (MAP) was continuously monitored. Cytokines were measured via multiplex bead immunoassays. Survival time was observed for 9 hours after the intervention and assessed by Kaplan-Meier statistics. The overall survival in each group was compared using Fisher's exact test. Finally, we used a Cox proportional-hazards model to examine the effects of cytokine removal on survival time.

Measurements and main results: Baseline plasma cytokine concentrations and MAP were similar between hemoadsorption and sham-treated groups. However, the concentrations of tumor necrosis factor, interleukin (IL)-1beta, IL-6, and IL-10 were significantly lower after hemoadsorption compared to the sham group. Six hours after treatment ended, IL-6 and IL-10 concentrations were still lower in hemoadsorption group. MAP was significantly better in hemoadsorption compared to sham-treated animals (p < .05). Finally, mean survival time was significantly longer (720 vs. 381 min, p < .05, Mann-Whitney test), and overall survival was significantly better (11/17 vs. 2/16, p < .01) with hemoadsorption compared to sham. Combined reduction in both IL-6 and IL-10 was associated with a significantly decreased risk of death (hazard ratio, .11, p = .005).

Conclusion: Hemoadsorption reduced circulating cytokines, improved MAP, and resulted in better short-term survival in CLP-induced septic rats.

Conflict of interest statement

The authors have not disclosed any potential conflicts of interest.

Figures

Figure 1

Effects of hemoadsorption on cytokine removal (mean ± sem, pg/mL). Hemoadsorption is shown in solid bars while sham results are shown in open bars. The cytokine data were log-transformed (ln). Each panel shows a separate cytokine: A, tumor recrosis fator (TNF); B, interleukin (IL)-1β; C, IL-6; D, IL-10. All four cytokines showed significant differences over time (p < .05) and between groups (p < .05). For pair-wise comparisons: *hemoadsorption vs. sham (p < .05) and †compared with baseline (p < .05).

Figure 2

Effects of hemoadsorption on mean arterial pressure (MAP) (mean ± sem, mmHg). Hemoadsorption is shown in dashed line while sham results are shown in solid line. MAP was significantly different over time and between groups (p < .01). For pair-wise comparisons: *hemoadsorption vs. sham (p < .05) and †compared with baseline (p < .05).

Figure 3

Effects of hemoadsorption on short–term survival. Survival time (hr) was observed from the start of intervention up to 12 hrs. Hemoadsorption results are shown as a dashed line while sham results are shown as a solid line. Survival time was significantly greater in the hemoadsorption group (p = .02) and overall survival (until 12 hrs) was significantly improved (p < .01).

Figure 4

Relationship between changes in cytokines (pg/ml) and change in mean arterial pressure (MAP) (mm Hg) before and after hemoadsorption or sham. Interleukin (IL)-6 (ρ = −.74, p < .001) and IL-10 (ρ = −.69, p < .01) showed inverse correlations with MAP; tumor necrosis factor (TNF) (ρ = −.14, p = .55), IL-1β (ρ = −.11, p = .69), were not.

Figure 5

Relationship between changes in cytokines (pg/mL) before and after hemoadsorption or sham and survival time. Interleukin (IL)-6 (r = −.77, p < .001) and IL-10 (r = −.61 p < .01) showed inverse correlations with survival. Neither tumor necrosis factor (TNF) (r = −.24, p = .36) nor IL-1β (r = −.48, p = .09) were significant.