Plasmapheresis of horses by extracorporeal circulation of blood.

This research discusses an efficient method of collecting plasma from horses through a device that allows for extracorporeal circulation of blood. With this technique, researchers managed to gather about 2.5 kg of plasma protein from a horse over three weeks without any evident negative impact on the horse. The plasma protein levels of the horse’s blood slightly decreased initially but later returned to normal after a rest period of three weeks.

Methodology

• The scientists used a custom-made device that facilitated extracorporeal circulation of blood — a process where the blood is diverted outside of the horse’s body, allowing plasma collection.
• They tried this technique on a horse for a period of three weeks, during which they managed to collect approximately 2.5 kg of plasma protein.

Observations and Results

• Throughout the experimental period, the blood’s packed cell volume, which measures the volume percentage of red blood cells in blood, did not show significant changes.
• However, a drop in the plasma protein concentration in the horse’s bloodstream was observed.
• After pausing the experiment and allowing the horse a rest period of three weeks, the plasma protein levels slowly recovered and nearly reached normal levels again.

Additional Research

• In a further experiment, the horse was immunized with tetanus toxoid, a vaccine used to prevent tetanus, and then subjected to repeated plasmapheresis cycles.
• This led to a consistent decrease in the antibody titre, indicating a fall in the blood’s antibody concentration against the applied antigen (tetanus toxoid).

Implications and Conclusions

• Overall, the research indicates that this method of plasma collection from horses via extracorporeal circulation is feasible and does not lead to obvious adverse effects on the animal’s overall health.
• Despite a temporary decrease in plasma protein levels, the horse’s ability to replenish these levels during a rest period suggests the procedure’s impact is manageable and relatively minimal.
• However, the observed decrease in antibody titre during repeated cycle implies that the method might affect the horse’s immune response when subjected to immunization concurrently with plasmapheresis.