An inside view of arthritis
Arthritis is very common - so common, indeed, that aching joints may seem inevitable as we age. They are not, of course, and even if the condition does set in, treatment can often slow it down. MRI combined with nanoparticles developed by an EU-funded project could soon help to spot main forms of the disease much earlier.
© hriana - Fotolia.com
The NanoDiaRA project developed a nanoparticle-based system for the detection of osteoarthritis and rheumatoid arthritis, the two most common forms of the disease, which is a leading cause of pain and disability. “Our particles are designed for use as a contrast agent in magnetic resonance imaging [MRI],” says scientific coordinator Dr Margarethe Hofmann of MatSearch Consulting Hofmann in Switzerland.
The particles, once injected, are easy to detect with such a scan. Using this approach, doctors would be able to confirm likely cases earlier and more accurately than with current methods, says Professor Heinrich Hofmann of the Swiss Federal Institute of Technology of Lausanne, who led the work on the actual particles. They would also obtain a clear view of the extent of inflammation and potential damage in the affected joints.
Arthritis can take many forms, and the treatment must be tailored. But it can be hard to work out if the problems and pain a patient is experiencing are actually caused by arthritis, and if so by which form — especially in the early stages, where there may not be much to see on an X-ray. At the moment, the NanoDiaRA researchers explain, diagnosis in such cases is based primarily on an assessment of the symptoms.
Using the project’s specialised nanoparticles, this hurdle to prompt treatment of osteoarthritis and rheumatoid arthritis could be overcome, the husband-and-wife team notes. The particles are designed to flag and distinguish the two forms reliably, even in the absence of any characteristic damage.
The trick is in the coatings, Professor Hofmann explains. The outer layer of the nanoparticles contains molecules that bind to distinctive biomarkers, i.e. substances specific to the two types that form as these illnesses progress.
The core of the particles is composed of iron oxide, which the liver begins to break down in a matter of days, he adds. The iron is subsequently absorbed into the blood.
Iron oxide was already known to be a suitable material for this purpose, Professor Hofmann remarks. Initial toxicology tests conducted by the project indicate that the approach is safe, and further checks would of course be carried out in preparation of future clinical trials. Other systems involving such nanoparticles have already been developed, he adds, but they are still very rare.
In addition to the proposed application in imaging, NanoDiaRA’s nanoparticles can also be used to analyse samples of blood or urine. The project has developed diagnostic kits that can help to establish if an MRI should be considered. “You wouldn’t inject particles in vivo without good reason, and there is also a cost factor as MRI is expensive. So it’s better to examine a sample first,” the Hofmanns explain.
Into the clinics?
The project also considered the ethical and legal implications of using this type of technology, which the partners notably debated with patient organisations and the wider community at a number of events.
This comprehensive and open dialogue enabled all parties to explore the potential and the concerns associated with proposed solution, Dr Hofmann reports, but when this innovation might be introduced into clinical practice currently remains unclear. On the whole, the individuals and organisations that engaged with NanoDiaRA seemed open to the possibilities, she notes, but the regulatory framework has yet to be defined.
In addition, massive investments would be needed to develop NanoDiaRA’s nanoparticles into a licensed product. The project ended in January 2014, and the partners are currently exploring opportunities to take its outcomes forward.
Among other developments, the system is now being adapted to detect metastases in lymph nodes, and it could be tailored to many other diseases, Professor Hofmann says. “All we would need to do is change the molecule that binds to the markers,” he concludes. In theory, the possibilities are endless.