Feasibility of hemoperfusion using extracorporeal therapy in the horse.

Objective: Develop, implement, and monitor for adverse effects of, a novel hemoperfusion therapy in adult horses. Methods: A prospective, observational feasibility study using three healthy adult horses from the North Carolina State University teaching herd. Health status was determined by physical exam, complete blood count, coagulation panel, and serum biochemistry. Each horse was instrumented with a 14 Fr × 25 cm double-lumen temporary hemodialysis catheter and underwent a 240 min polymer-based hemoperfusion session. Horses were administered unfractionated heparin to maintain anti-coagulation during the session. Given the novelty of this therapy in horses, each horse was treated as a learning opportunity that informed an iterative process of protocol development and modification. Measurements and main results: Our long-term goal is to investigate potential clinical applications of hemoperfusion in horses, including cytokine reduction in horses with severe SIRS/sepsis. Horses were monitored for changes in clinical exam, biochemistry and hematology parameters. Additionally, cytokines were quantified to determine whether extracorporeal hemadsorption therapy alone caused an inflammatory response. Our results show that hemoperfusion therapy was associated with decreased platelet counts and serum albumin concentration. There was no significant change in plasma cytokine concentrations with hemoperfusion therapy. In one horse, the cytokine concentrations decreased, as previously reported with hemoperfusion therapy in humans. Hypothesis: We hypothesized that hemoperfusion therapy could be performed in healthy adult horses without significant adverse effects. Conclusion: Polymer-based hemoperfusion is a feasible extracorporeal therapy (ECT) modality for adult horses. Additional studies are needed to further establish clinical protocols, as well as establish efficacy of polymer-based hemoperfusion for treatment of various conditions in horses, including intoxications, immune-mediated conditions, and sepsis.

Hemadsorption extracorporeal therapy removes cytokines ex vivo in horses.

OBJECTIVE: Plasma cytokine adsorption has shown benefit as an adjunctive therapy in human sepsis but has yet to be investigated in horses. We hypothesized that ex vivo filtration of equine plasma with a novel cytokine adsorption device would significantly reduce concentrations of lipopolysaccharide-stimulated cytokines. We also hypothesized that the device would adsorb medications commonly used to treat sepsis. ANIMALS: 8 horses owned by North Carolina State University. METHODS: Four liters of heparinized whole blood was collected from healthy adult horses (n = 8) and stimulated with lipopolysaccharide (100 ng/mL) for 6 hours (37 °C.) from June 4, 2023, to December 15, 2023. Plasma was filtered through a cytokine adsorption device or sham circuit. Samples were collected at 11 time points for multiplex cytokine analysis. Chemistry analysis was performed before and after filtration. To investigate the impact of the device on medication concentrations, equine plasma containing potassium penicillin, gentamicin, and flunixin meglumine was filtered through the cytokine adsorption device or sham for 6 hours. Drug concentrations before and after filtration were determined by ultra-high-performance liquid chromatography. Prefiltration versus postfiltration sample concentrations were analyzed by Student paired t test using GraphPad Prism 9.0 (P < .05). RESULTS: Filtration of lipopolysaccharide-stimulated equine plasma (n = 8) for 6 hours resulted in significant mean reductions in the cytokines IL-10, IL-5, IL-8, tumor necrosis factor-α (TNF-α), and IL-1ß, as well as albumin. Drug concentrations of potassium penicillin, gentamicin, and flunixin meglumine were also significantly reduced by filtration. CLINICAL RELEVANCE: This work provides proof of concept for further investigation of extracorporeal cytokine adsorption as a potential adjunct treatment for equine sepsis.

Asthma: The Use of Animal Models and Their Translational Utility.

Asthma is characterized by chronic lower airway inflammation that results in airway remodeling, which can lead to a permanent decrease in lung function. The pathophysiology driving the development of asthma is complex and heterogenous. Animal models have been and continue to be essential for the discovery of molecular pathways driving the pathophysiology of asthma and novel therapeutic approaches. Animal models of asthma may be induced or naturally occurring. Species used to study asthma include mouse, rat, guinea pig, cat, dog, sheep, horse, and nonhuman primate. Some of the aspects to consider when evaluating any of these asthma models are cost, labor, reagent availability, regulatory burden, relevance to natural disease in humans, type of lower airway inflammation, biological samples available for testing, and ultimately whether the model can answer the research question(s). This review aims to discuss the animal models most available for asthma investigation, with an emphasis on describing the inciting antigen/allergen, inflammatory response induced, and its translation to human asthma.

Investigation of plasma cell-free DNA as a potential biomarker in horses.

Plasma cell-free DNA (cfDNA) is a biomarker of ischemia, systemic inflammation, and mortality in humans with gastrointestinal disease. Cell-free DNA has not been investigated as a biomarker for equine colic, to our knowledge. We hypothesized that cfDNA could be measured accurately in neat equine plasma using a benchtop fluorometer and that plasma cfDNA would be elevated in emergency patients compared to healthy horses. Plasma was obtained from blood collected in Roche DNA stabilizing tubes. We used the Qubit 4 fluorometer and 1× dsDNA HS assay kit to measure cfDNA concentration in neat patient plasma and following DNA extraction of plasma with a commercial kit. Assay precision and linearity of dilution were satisfactory for neat plasma cfDNA, but DNA spike and recovery results were variable. Further, cfDNA concentrations in paired neat plasma and extracted-plasma samples (n = 66) were not correlated. Median extracted-plasma cfDNA was higher in emergency patients (n = 50) and a subgroup of colic patients (n = 36), compared to healthy horses (n = 19). Our results with extracted-plasma samples provide proof of concept for further investigation of plasma cfDNA as a biomarker in horses.