Hemoperfusion with a polymer-based column alters inflammatory responses in lipopolysaccharide-treated horses in vivo.

Overview

• This study investigated how hemoperfusion using a polymer-based column affects inflammatory responses and immune cell function in horses treated with lipopolysaccharide (LPS), a component that induces endotoxemia (a model for sepsis).
• The researchers found that hemoperfusion altered neutrophil activity and apoptosis but did not significantly change systemic cytokine levels, suggesting potential benefits for treating immune dysfunction caused by endotoxemia in horses.

Research Objective

• To determine the effect of hemoperfusion with a polymer-based column on systemic cytokine concentrations.
• To evaluate changes in neutrophil dysfunction in horses treated with lipopolysaccharide (LPS), which induces endotoxemia, a condition mimicking sepsis.

Study Design and Methods

• Subjects: Six university-owned adult horses.
• Induction of Endotoxemia:
  • Horses received an intravenous bolus of LPS at 60 ng/kg.
  • This was followed by a continuous intravenous infusion of LPS at 60 ng/kg over one hour.
  • Endotoxemia confirmation was based on clinical signs and presence of neutropenia (decreased neutrophil counts).
• Experimental Design:
  • A crossover model was used, running from January 2024 to July 2024.
  • Hemoperfusion treatment lasted 4 hours using either a sham device or a polymer-based column designed to filter blood.
  • Multiple blood samples were collected at 5 different time points over 72 hours for flow cytometry analysis.
  • Additionally, 14 time points’ blood samples were taken to analyze systemic cytokine levels via multiplex assays.

Key Findings

• Neutrophil Responses:
  • Horses treated with the polymer column showed increased neutrophil apoptosis (programmed cell death) both early and late after treatment compared to sham-treated horses.
  • The treated horses had improved reactive oxygen species (ROS) production following stimulation post-filtration, indicating enhanced neutrophil functional response.
• Complete Blood Count (CBC):
  • Two out of five horses treated with the polymer column demonstrated better CBC parameters after treatment.
  • No improvement was observed in horses treated with the sham filter.
• Systemic Cytokines:
  • No significant differences in systemic cytokine levels were found between horses treated with the polymer column and those receiving sham treatment.
  • This suggests that the hemoperfusion affected immune cell function but did not broadly reduce systemic inflammation markers in this model.

Implications and Conclusions

• The study provides “proof of concept” that hemoperfusion with a polymer-based column can modify certain negative immune responses induced by LPS, particularly improving neutrophil function and apoptosis.
• These findings indicate a potential novel adjunctive therapy for managing endotoxemia or sepsis in horses.
• Because the model used intravenous LPS infusion rather than naturally occurring clinical sepsis, additional research is needed to test hemoperfusion in horses suffering from actual sepsis.
• Further refinement and optimization of this therapeutic approach are recommended to maximize clinical benefits.

Study Limitations and Future Directions

• The endotoxemia induced by LPS infusion may not fully replicate the complexity and variability of naturally occurring sepsis in horses.
• The small sample size (six horses) limits broad generalizability and statistical power.
• Systemic cytokine levels did not change significantly, suggesting that the polymer column’s effect might be subtler or require further optimization.
• Future research should involve:
  • Clinical trials in horses with sepsis under field conditions.
  • Adjustment of hemoperfusion protocols, including duration and timing relative to disease progression.
  • Exploration of how hemoperfusion affects other immune and metabolic parameters.