Vet Claims Progress on Horse Bleeding : Racing: Researcher says he’s refined drugs for pulmonary hemorrhage, an exercise-induced malady that afflicts thoroughbreds.

A Silver Spring, Md., veterinary researcher claims to have isolated an abnormality of the red blood cells that he believes to be the cause not only of exercise-induced pulmonary hemorrhage in racehorses but of other exercise-induced maladies common in racehorses. He also claims to have developed drugs that will correct the problem.

According to Dr. John H. Boucher, there is evidence that the red blood cell disease echinocytosis is the root of a number of “exertional diseases” found in most thoroughbreds, pulmonary hemorrhage (commonly known as “bleeding”) foremost among them. Echinocytosis, he claims, develops spontaneously when horses exercise intensely and is linked to muscle and orthopedic disease, exercise intolerance and equine sudden death. The occurrence of echinocytosis is marked by the spontaneous production of a large number of abnormal red blood cells called echinocytes. These are rigid cells that clump together, rupturing small blood vessels through which they have difficulty flowing, thereby disrupting the entire circulatory system.

Echinocytes may be the missing link in understanding the origin of diseases associated with exercise, Boucher claims. Horses are the only species known to suffer disease as a result of exercise, Boucher said.

“An estimated 50% of horses that start into training never make it to the race track, but become discards due to exertional diseases or injury,” Boucher said. “Healthy thoroughbreds should be capable of racing about every 10 to 14 days. But not so, because of inevitable injuries and diseases associated with exercise.”

Studies undertaken in 1988 at Canterbury Downs by University of Minnesota researchers determined the blood of thoroughbreds to be three to four times more viscous immediately after a race than at rest. They also determined the cellular component of blood volume is 58% higher after exercise. Rigid red blood cells more than doubled by the end of a race.

Boucher’s company, Rheotech Labs, is developing therapeutic drugs known as hemorrheologic agents, which would correct the echinocyte problem by normalizing blood flow. These are being tested on horses at the University of Minnesota. Boucher envisions the drugs as replacements for current methods of treatment, particularly for furosemide (Lasix), which recent studies claim is not effective in treatment of pulmonary hemorrhage and acts as a performance-enhancing agent. Lasix, while prohibited for racing use in New York, is legal and widely used elsewhere.

Boucher’s research is a great distance and a substantial amount of developmental funding short of being approved by the Federal Drug Administration and eventually reaching the marketplace. It is further still from approval for racing purposes.