Cardiovascular Changes With Moldy Corn Poisoning

Fumonisins are toxic byproducts of the fungus Fusarium verticilloides, which often grows on corn. These mycotoxins can cause leukoencephalomalacia (moldy corn poisoning) in horses, and are undetectable to the naked eye. Horses exposed to only 0.2 mg fumonisin/kg body weight for several days can develop non-specific neurological signs including changes in personality, behavior, and balance. While the mechanism of the neurotoxicity remains unclear, fumonisins are known to interfere with the metabolism of fats called sphingolipids. When these fats build up in the blood, they affect cardiovascular function; however, this doesn't explain why horses develop neurological signs.

A recent study from the University of Illinois attempted to determine if horses purposely fed and injected with fumonisin develop increased serum sphingolipids and decreased cardiac function preceding neurological signs. The horses did develop cardiovascular problems, including decreased heart rate, heart contractility, and cardiac output. Increased concentrations of sphingolipids were detected in both serum and heart muscle, and all horses developed neurological signs consistent with leukoencephalomalacia.

The authors speculate that decreased cardiac function might have caused uncontrolled dilation of blood vessels in the brain, causing swelling, increased intracranial pressure, and brain damage. This theory requires further study. (For more on mycotoxins, see "Mysterious Mycotoxins" in the August 2002 issue of The Horse, Article Quick Find #3695 at

Smith, G.W.; Constable, P.D.; Foreman, J.H.; et al. American Journal of Veterinary Research, 63(4), 538-545, 2002.

About the Author

Susan Piscopo, DVM, PhD

Susan Piscopo, DVM, PhD, is a free-lance writer in the biomedical sciences. She practiced veterinary medicine in North Carolina before accepting a fellowship to pursue a PhD in physiology at North Carolina State University. She lives in northern New Jersey with her husband and two sons.

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