Heparin-induced agglutination of erythrocytes in horses.

The research study examines the impact of heparin administration on erythrocytes (red blood cells) in horses, including significant changes in red blood cell count and structure, with a specific focus on the phenomenon of erythrocyte agglutination.

Experimental Design

• The research was divided into two experiments. Five horses given heparin constituted the first experiment group, while another five horses served as time-matched controls, not treated with heparin. In the second experiment, three horses were given heparin.
• Heparin was administered subcutaneously (under the skin) twice daily for four days in both experiments.
• Measurements of the packed cell volume (PCV), erythrocyte (red blood cell) count, and hemoglobin concentration were taken and analyzed.
• To investigate the presence of agglutination (clumping together) in the erythrocytes, saline wet mounts of erythrocyte suspensions (samples) were closely examined, with or without exposure to a dilute trypsin solution, which can break up protein clumps.

Observations and Findings

• Significant decreases in PCV, erythrocyte count, and hemoglobin concentration were observed in horses during heparin therapy in the first experiment.
• The mean corpuscular volume (MCV, a measure of the average volume of red blood cells) of the heparin-treated horses peaked at 66.1 femtoliters on the final day of treatment – suggesting that the cell size increased.
• An increase was also noticed in erythrocyte creatine concentration and glucose 6-phosphate dehydrogenase activity, both markers of cell metabolism.
• These changes suggest that the increase in MCV was not primarily due to the release of large immature erythrocytes from the bone marrow – the site of red blood cell production.
• In the second experiment, the presence of erythrocyte agglutination was evident from the first day of therapy, showing heparin affected the erythrocytes’ tendency to clump together.
• The level of agglutination increased as the days of treatment progressed, and it could be reversed with exposure to trypsin solution, suggesting a protein-mediated process was likely involved.
• The increase in agglutination was associated with a decreased erythrocyte count and a sharp increase in MCV in the samples processed normally, probably due to clumped cells being treated as a single unit in the count.

Conclusion

• The research concludes that heparin therapy in horses led to significant changes in erythrocyte count and characteristics, including an increase in cell size and a tendency for cells to clump together (agglutinate), which had an impact on blood test results.
• The reversal of agglutination after exposure to trypsin indicates a potential area for further investigation to understand the underlying biochemical processes.