Nanoparticles to Diagnose, Treat Equine Medical Conditions?

Nanoparticles to Diagnose, Treat Equine Medical Conditions?

A standard bone scan camera, like the one seen here, was used to locate where the nanoparticles went in the horses' bodies one, 12, and 21 hours post-injection.

Photo: Mathieu Spriet, DVM, MS, Dipl. ACVR, ECVDI/UC Davis

One of the most difficult parts of an equine veterinarian's job is trying to diagnose a problem deep within the chest or abdomen of a sick horse. Even with ultrasound, X rays, CT scans, and MRI, it is often nearly impossible to figure out exactly what and where the problem is. But new research from a group of veterinary researchers indicates that sometimes the way to figure out the big picture in equine medicine is by using something extremely small.

"Nano-technology refers to the use of microscopic nanoparticles measuring less than 1000 nanometers in diameter that can be injected into the bloodstream and 'pool' at sites of infection, inflammation, and even neoplasia," explained Claire Underwood, MA, VetMB, MRCVS, School of Veterinary Science at the University of Queensland-Gatton Campus in Australia.

Recognizing the immense potential of these nanoparticles not only for the early diagnosis of infection, inflammation, and tumors, but also for targeted drug delivery, Underwood and a team of Dutch researchers evaluated the safety and distribution of specially designed nanoparticles in horses.

Ten healthy horses received an intravenous dose of nanoparticles, some of which were labeled with technetium-99 (99mTc), the same radioactive isotope that is used during bone scans in horses. A standard bone scan camera was then used to locate where the nanoparticles went in the horses' bodies one, 12, and 21 hours post-injection.

Key findings included:

  • No adverse reactions occurred following injection of the nanoparticles;
  • Mild increases in the heart and respiratory rates were detected at 20 and 25 minutes post-injection; and
  • The nanoparticles circulated in the bloodstream for 21 hours and consistently "pooled" in the liver, spleen, kidney, and lungs.

"These nanoparticles appear well-tolerated in horses and, therefore, have the potential to greatly improve the diagnosis of certain medical conditions as well as the treatment of many conditions via targeted drug delivery, including pneumonia, because of the high accumulation of these particles in the lungs," concluded Underwood.

Additional studies are needed to define how well these nanoparticles accumulate in affected tissues during different disease processes in the horse, and the efficacy of nanoparticles for targeted delivery of pharmaceuticals to diseased tissue.

Underwood added, "Further work is being performed at the University of Queensland, Australia, to investigate nanoparticle drug delivery to prevent laminitis, treat inflammatory airway disease, and 'image' infection in horses."

The article, "Intravenous technetium-99m labeled PEG-liposomes in horses: A safety and biodistribution study," will be published in an upcoming edition of the Equine Veterinary Journal. The abstract is available online.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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