Mr Cool's victory in the Stanleybet Long Distance Handicap Hurdle at Haydock Park Racecourse, England, on Saturday, May 7 was noteworthy due to pioneering tendon treatment he had received.
After the 11-year-old suffered a tendon injury in March of 2004, part-owner Nick Mills approached Britain's VetCell BioScience Ltd., which, in partnership with the Royal Veterinary College of London, had discovered a method of using stem cell technology to repair damaged tendons and ligaments.
Mr Cool underwent treatment which involved extracting bone marrow from his sternum while he was sedated. The bone marrow, a rich source of mesenchymal stem cells, was then taken to the laboratory where stem cells were isolated and multiplied to in excess of four million cells. The cells were suspended in a nutrient-rich bone marrow supernatant before being injected into the site of the site of the injury. The aim of this was to promote the re-growth of flexible tendon tissue, rather than allowing less pliable and more injury-prone scar tissue to form.
After the completion of procedures, Mr Cool was placed on a regime of controlled exercise. He returned to racing action in April, 2005 at Sandown Park, finishing unplaced in a handicap hurdle before winning Saturday in his second start back at Haydock, just 51 weeks after his treatment.
Dr. Roger Smith, professor of equine orthopaedics at the Royal Veterinary College, who is working in partnership with VetCell, explained: "Traditionally this injury has a poor prognosis. Conventional therapies result in a scarred tendon and those animals that do make it back to competition after a lengthy convalescence often don't seem to perform as well and have a high risk of re-injury.
"However, the implantation of actual live cells into the tendon lesion, rather than using drugs, for the first time offers the prospect of a return to a fully functional tendon."
The majority of horses treated in the past two years have been jump racehorses, although eventers, show jumpers and dressage horses have also benefited from the treatment.
VetCell's Dr. David Mountford, said: "Over 100 horses have been implanted using this technique and, looking at the anecdotal results so far, we are seeing well over twice as many animals returning to the racetrack as might have been expected under conventional treatments.
"Mr Cool is the first high-profile winner although other horses have won repeatedly at and above their pre-injury level of performance. We have a number of other high-profile horses currently undergoing post-implantation rehabilitation."
Another use of the technology is to extract stem cells at birth from the umbilical cord straight after a foal is born. The cells can then be stored cryogenically for future use in the treatment of injuries. A number of leading studs in the UK are utilizing this service, including Hamdan al Maktoum's Shadwell Stud.
Mountford added: "The bone marrow extraction and stem cell implantation techniques can be carried out by the horse's normal veterinarian or at a referral center. The process is fairly straightforward, although we offer training to veterinarians in order to highlight particular elements of the techniques. The really complex bit happens in the labs with the separation and culture of the cells. This provides a suspension containing in excess of four million stem cells for implantation directly into the lesion."
Although only available in Europe and most of the Middle East at present, this stem cell therapy, which has been patented, is also creating interest in Australia. VetCell Bioscience hopes it will be offer the technique globally within the next 12 months.