By Mark Andrews

A new gene therapy shows promise for treating tendon injuries according to a report published in the journal Frontiers in Veterinary Science. The authors claim the technique gives much faster healing than current methods and could significantly reduce relapse rates.

The use of gene therapy in two horses with naturally occurring injuries of the suspensory ligament or the superficial digital flexor tendon (SDFT) is described by Milomir Kovak of the Moscow State Academy of Veterinary Medicine and Biotechnology, with Yaroslav A Litvin of the Kazan Federal University, and others. Scientists at Kazan Federal University, Moscow State Academy, and The University of Nottingham collaborated in the work.

Two male dressage horses were the subjects of the study. One had desmitis of the lateral branch of the suspensory ligament; the other, tendinitis of the superficial flexor tendon.

The treatment involved introducing genes for two specific equine growth factors into the damaged tissue. Plasmid DNA (pDNA) was used to carry genes for equine vascular endothelial growth factor (VEGF) 164 and fibroblast growth factor 2 (FGF2). Both the genes were derived from horses, resulting in the biosynthesis of natural horse proteins in the treated animals.

The authors explain: “VEGF164 is a member of a large VEGF proteins family, which promotes proliferation and migration of endothelial cells. FGF2 stimulates proliferation of cells, regeneration of nervous, muscular, and connective tissue.”

The pDNA was injected directly into the affected structures under ultrasound guidance on one occasion. Progress was monitored by clinical examination and ultrasound scans.

Two to three weeks after the treatment, the authors report that the horses could walk and trot. Within just two months they were back to full health, galloping and competing in dressage competitions.

“Advancing medicine, relieving pain and restoring function were the main aims of this study,” says Professor Albert Rizvanov, who led the study and is based at Kazan Federal University. “We have shown that these are possible and within a much shorter time span than treatments available at the moment. In addition, we could use this type of therapy in other injuries and in many other situations ranging from fertility problems through to spinal cord injuries.”

“This pioneering study advances not only equine medicine but has real implications for how other species and humans are treated for lameness and other disorders in the future,” says Dr. Catrin Rutland, Assistant Professor of Anatomy and Developmental Genetics at the University of Nottingham. “The horses returned to full health after their injuries and did not have any adverse side effects. This is a very exciting medical innovation.”

The authors conclude: “Since these preliminary case reports demonstrated improvement in clinical outcome and no adverse side effects, a larger clinical trial is ongoing to further study efficiency of direct gene therapy for the treatment of horse tendinitis and desmitis.”

Printed with permission of Mark Andrews, Equine Science Update.

This article was originally published in Canada’s Equine Guide 2018, a publication of Canadian Horse Journal. 

Main article photo: Shutterstock/Osetrik