Understanding the Mechanisms of Diarrhea in Horses

SUMMARY: Researchers will study the fluid shifts in the large intestine of horses, with a special focus on diarrhea caused by Clotridioides difficile.

THE PROBLEM: The horse has a unique intestinal tract among animals. Because ofthis, studies on the intestine performed in other species, such as mice, are often not applicable.The horse’s gut is characterized by an enormous large intestine that uses helpful bacteria to break down food for energy. However, sometimes the horse’s gut can become infected with bacteria that are not helpful. Some of these bacteria can cause serious complications, including diarrhea, dehydration and death. One of the ways in which diarrhea occurs is through “turning on” and “turning off” the channels found on the gut’s lining. Normally the channels help the horse absorb nutrients and expel waste. If the channels are not working properly and are eitheractively secreting or not absorbing substances such as sodium, glucose and chloride, waterremains in the intestine, and diarrhea results. Getting a better understanding of how the channels operate could improve treatment.

THE PROJECT: Previously, in order to study the horse’s intestine, samples had to be obtained through invasive methods, including surgery or after death. The research team has developed a less-invasive method of sampling, using rectal tissue as a model for the large intestine. The horse only needs to be lightly sedated to obtain this sample. The first goal of the project is to make sure that rectal tissue mimics the large intestine well enough to serve as a model. The second goal is to determine how the harmful bacteria commonly known as C. diff (Clostridioides difficile) causes diarrhea in the horse. C. diff produces a toxin that may turn off the transporters that absorb sodium and glucose. When sodium and glucose are not absorbed, water remains in the intestine and the horse develops diarrhea. It is important to understand the cellular mechanism behind C. diff diarrhea in the horse as this is the first step in developing a treatment. 

POTENTIAL IMPACT: If the effect on the ion transporters can be limited, then it is likely that C. diff will result in less severe diarrhea in horses. Improving therapy could help thousands of horses each year, and potentially be used to treat diarrhea caused by different mechanisms.

Projected End Date: 2/28/27