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