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

To determine the effect of hemoperfusion with a polymer-based column on systemic cytokine concentrations and neutrophil dysfunction in lipopolysaccharide-treated horses in vivo. 6 university-owned horses received 60 ng/kg lipopolysaccharide, IV, as a bolus and then 60 ng/kg, IV, as a constant rate infusion over 1 hour. Endotoxemia was confirmed by clinical signs and neutropenia. In a crossover model that was completed from January 2024 through July 2024, hemoperfusion was performed for 4 hours with either a sham or polymer column. Blood was collected at 5 time points over a 72-hour period for flow cytometry analysis and 14 time points for cytokine multiplex analysis. There were significant differences between column treatment and sham treatment, including increased early and late neutrophil apoptosis and improved reactive oxygen species production in response to stimulation at the postfiltration time point. Additionally, 2 of 5 column-treated horses had improved CBC parameters compared to 0 of 5 sham-treated horses. Systemic cytokines were not significantly different between column and sham treatment. The results of this study provide proof of concept for hemoperfusion with a polymer-based column as a potential treatment to mitigate deleterious lipopolysaccharide-induced immune responses in adult horses. Further investigation and optimization of hemoperfusion as an adjunctive treatment for sepsis in the horse is warranted. Because there are known differences in lipopolysaccharide infusion and clinical sepsis, further investigation in horses with clinical sepsis is needed.