Estimates suggest nearly two percent of people in the UK suffer from disabling tendon problems. These make joints painful, stiff, tender and weak.
Some people's symptoms come on gradually, with the condition of a tendon slowly deteriorating. Other people suddenly find themselves in agonising pain when a tendon tears (tendons are like cables linking muscle to bone).
Symptoms usually drag on for weeks or months. Treatments include rest, physiotherapy and anti-inflammatory drugs, though these are often ineffective. As a last resort, some people undergo surgery which can be effective but often involves a long and painful period of rehabilitation.
The many people who get little benefit from treatment must face up to the fact that their joint may simply never get better. They are forced to make major changes to their way of life, such as giving up a much-loved sport or even quitting their job.
The research team started this project after generating exciting new information. They compared the Achilles tendons of people in pain with those of healthy people. They found that a substance called MMP-23 is produced in greater quantities in the painful tendons.
MMP-23 had never been found in tendons before, and no-one knew what it does there. It is a type of protein, called a protease , which acts like a pair of biological scissors to break down other proteins. Researchers suspect it might accelerate the destruction of tendons.
This project aims to find out as much as possible about MMP-23 in both normal and painful tendons. Researchers will investigate how cells make it and how its production is controlled - by naturally occurring molecules, different drugs and mechanical strain on the tendons. They will study exactly what it does in tendons and how it works, and ascertain why its levels are increased in painful tendons.
These researchers have a long history of investigating tendon disease. Together, they have all the skills and experience needed to make a success of this project.
Dr Riley has led the research team for almost ten years. He has an international reputation for his studies, having published 27 full research papers on tendon problems, as well as several reviews, editorials and book chapters. He co-edited a textbook on Soft Tissue Rheumatology, which was awarded 'Medical Book of the Year', in 2004, by the Royal Society of Medicine and Society of Authors.
The laboratories at the Rheumatology Research Unit are well equipped and benefit from the proximity of many other facilities within Addenbrooke's Hospital and the University of Cambridge.
If MMP-23 does indeed have a role in tendon degeneration, it will become an obvious target for drug therapy. The race would be on to design new drugs that stop MMP-23 from damaging healthy joint tissue - drugs that could work where so many other treatments have failed.
But we need to know as much as possible about MMP-23 if we are to target it accurately with new drugs. This project will generate extensive information, in the high level of detail needed when designing new drugs.
Ultimately, the hope is to find a treatment that alleviates pain, and increases strength and flexibility in joints, allowing the one million or so people with tendon problems to live a more normal life. A cure for tendon problems would bring so much more than simply an end to physical suffering - it would allow people to return to work and take up the sports and other hobbies that they enjoy.
