Achilles Tendon

FAPESP researcher at Unesp develops an alternative therapy to treat tendonitis in athlete horses with mesenchymal stem cells

By Mônica Pileggi

Agência FAPESP – An alternative mesenchymal stem cell cultivation technique developed by veterinary doctors at the Universidade Estadual Paulista (Unesp) in Botucatu, SP could be a solution for the complex problem of tendonitis in athletic horses.

Published in the Journal of Equine Veterinary Science, the  study coordinated by professor Ana Liz Garcia Alves was started in Master’s Degree work done by Armando de Mattos Carvalho, and was funded by FAPESP.

The technique involves extraction of progenitor cells derived from the adipose tissue from a region near the base of the tail and later implanting them in the animal so as to bring about regeneration of the injured tissue. Just like humans, horses that compete suffer muscular injuries, tendon inflammation being one of the most common problems.

Caused by the repetitive exertion of the animal’s limbs, the injury can lead to an early end to the animal’s athletic career. “There are many treatments, but to date none has proven to be entirely efficient,” Carvalho told Agência FAPESP.

The tendon of the superficial digital flexor muscle, located in the horse’s metacarpal region, is considered to be one of the most important and is where most inflammation takes place. The procedure known as enzymatic digestion is necessary to extract the stem cells from the fat taken from the horse. A collagenase solution is added to the adipose tissue, causing the entire extracellular matrix to be digested, liberating many types of cells, among them progenitor cells.

“After this process, these cells are cultivated and, as the mesenchymal stem cells have the characteristic of adhering to plastic, they are isolated from the other cells. After ten days of cultivation, it’s possible to get 10-20 million stem cells ready to be implanted in the animal,” he explained.

Healthy horses were selected for the study. The injury was caused on purpose with a collagenase injection that damaged the desired tissue—in this case, the tendon of the superficial digital flexor muscle. One group of the horses then received the stem cell implant in the region of the injury, and the other group didn’t. “The animals did physical therapy and had ultrasound and clinical analysis for five months,” explained Carvalho.

At the end of the period, a biopsy was performed for later microscopic histopathologic and immunohistochemical studies to evaluate repair in the injured tissue. “We compared the implant treated animals with those that had not been treated, and found that the tendon treated with stem cells was more organized, meaning that its fibers were more parallel,” he said.

Molecular biology

Driven by the positive results of his Masters work, Carvalho is continuing research on the topic in his doctoral research entitled "Autologous implant of mesenchymal stem cells and platelet-rich plasma associated in treatment of induced tendinitis in horses", also with FAPESP funding.  

The novelty in this next stage is the inclusion of molecular biology for evaluation of tissue repair. “We will select some genes normally present in healthy horse tendons for measurement and compare the quantities of these genes present in injured tendons that are treated and untreated with stem cells,” he indicated.

In the new study, Carvalho works with the implant of stem cells associated with platelet-rich plasma (PRP), which have the same potential to stimulate the development of scar tissue and regeneration as progenitor cells.

Read the article Use of Adipose Tissue-Derived Mesenchymal Stem Cells for Experimental Tendinitis Therapy in Equines (doi:10.1016/j.jevs.2010.11.014), by Armando de Mattos Carvalho and others at www.j-evs.com/article/S0737-0806(10)00510-1/fulltext.