Anti-Inflammatories Could Decrease EHV-1 Infection Rate
Editor's note: This article is part of TheHorse.com's ongoing coverage of topics presented at the 2012 American College of Veterinary Internal Medicine Forum, held May 30 - June 2 in New Orleans, La.
Colorado State University (CSU) researchers are one step closer to understanding how to slow the rate of neurologic equine herpesvirus-1 (EHV-1) infection.
At the 2012 American College of Veterinary Internal Medicine Forum, held May 30 - June 2 in New Orleans, La., Lutz Goehring, DVM, MS, PhD, Dipl. ACVIM, associate professor of equine medicine at the CSU College of Veterinary Medicine and Biomedical Sciences, discussed recent study results supporting the use of anti-inflammatory drugs during the viremic phase of EHV-1 infection.
Goehring explained that his team hypothesized that anti-inflammatory drug administration would decrease the number of contact molecules on endothelial cells, the inner lining of a blood vessel, and on virus-carrying cells (white blood cells or leukocytes) during EHV-1 viremia. This would reduce the interaction between virus-carrying cells and central-nervous-system endothelial cells, which he considers the most likely initiating cause of neurologic EHV-1.
The research group used a previously established in vitro (in the lab) model. In this in vitro study, Goehring et al. allowed contact between endothelial cells in culture and virus-infected leukocytes either with or without the presence of one of three anti-inflammatory drugs (flunixin meglumine, firocoxib, or dexamethasone) for four hours. The leukocytes were washed off and the endothelial cell monolayer was incubated for an additional 48 hours with or without the anti-inflammatories, he said. This was done to allow virus to replicate in the endothelial cells for easy detection, which shows as a "plaque" (essentially the amount of virus present).
The team found that all three anti-inflammatories significantly reduced the plaque counts compared to cells not incubated with medication.
"These results provide a rationale for the use of anti-inflammatory drugs during the early phases of EHV-1 infection," Goehring said. "Moreover, the use of anti-inflammatory drugs during viremia (virus in the bloodstream) may aid in preventing endothelial cell infection in vivo (in the live horse)."
"We further evaluated whether it is more important to block these 'contact molecules' on the leukocyte, or on the nervous system endothelial cell; results indicated that both sides require blocking with anti-inflammatories for optimal (and significant) result," he concluded. "Our next steps will be to identify the exact nature of the structures on cells."
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