Plasma clearance of [51Cr] albumin into the intestinal tract of normal and chronically diarrheal horses.

This study investigates the clearance of a radioactive label-tagged protein, albumin, in normal and chronically diarrheal horses to understand whether excessive plasma protein loss into the intestinal tract is a factor in equine intestinal disease. The research concludes that daily loss of plasma protein into the intestines of horses is minimal, and most horses with chronic diarrhea do not have a condition called protein-losing enteropathy.

Study Overview

• The study involved two groups of horses, one group consisted of five clinically normal mature horses whereas the other group involved eleven mature horses with chronic diarrhea.
• Both groups were administered 51Cr-tagged Cohn fraction V equine albumin intravenously, a protein found in plasma. The radioactive label 51Cr allows for tracing of the protein.
• All urine and feces were collected separately and blood samples drawn over a 5 to 8 day span post the injection. The plasma clearance rate of albumin into the intestinal tract was subsequently calculated for each horse.

Results for Normal Horses

• In healthy horses, the plasma clearance of albumin into the intestinal tract was 0.67 +/- 0.23 (SD) ml/kg of body weight/day.
• Approximately 1.33 +/- 0.69% of the radioactive dose ended up in the feces in 5 days. This suggests that the daily loss of plasma protein into the bowel of horses is small.

Results for Diarrheal Horses

• In eight out of the eleven diarrheal horses, the plasma clearance was 0.49 +/- 0.21 ml/kg/day with 1.12 +/- 0.68% of the radioactive dose found in a 5-day fecal collection. These results indicated that excessive losses of plasma protein into their bowels were not a part of their intestinal disease.
• However, in the remaining three diarrheal horses, a significant protein-losing enteropathy, a condition characterized by the loss of plasma proteins into the intestines, was observed. These horses had other additional pathological conditions like Mycobacterium avium infection and abnormal intercellular fluid accumulation.

Study Conclusions

• The study concludes that the daily loss of plasma protein into the intestines of horses is generally small, contradicting the possibility of excessive plasma protein loss being a significant factor in equine intestinal diseases.
• The key finding was that most horses with chronic diarrhea do not exhibit a protein-losing enteropathy, and this condition is limited to those with other significant pathologies or disease conditions.