The pain, swelling and stiffness caused by rheumatoid arthritis could one day be reduced thanks to an injection of ‘nanosponges,’ a study found.
While the breakthrough will not cure the autoimmune disease, it helps manage the condition that affects 1.3 million Americans and 400,000 Britons.
The neutrophil ‘nanosponges’ safely soak up and neutralize a variety of proteins that cause inflammation in the joints, usually of the hands, feet and wrists.
In mice, experimental injections of these nanosponges effectively brought severe rheumatoid arthritis under control – and also prevented the disease from developing in those that received shots early enough.
Professor Liangfang Zhang at the University of California San Diego cautions that the nanosponge treatment does not eliminate the disease, and we are far from a cure.
We are still far away from a cure for rheumatoid arthritis, but the closest relief we’ve found yet could come in the form of minuscule sponges of biodegradable polymer coated with the cell membranes of neutrophils, a type of white blood cell (illustration pictured)
Dr Zhang, of the department of nanoengineering, said: ‘We are basically able to manage the disease. It’s not completely gone. But swelling is greatly reduced and cartilage damage is minimized.’
The team hopes to one day see their work in human clinical trials.
The senior author at the university’s Jacobs School of Engineering explained: ‘Rheumatoid arthritis is a widespread and devastating autoimmune disease characterized by systemic inflammation that causes progressive joint damage and disability.
‘The precise cause of rheumatoid arthritis remains elusive, and current treatment primarily targets the inflammatory response.
‘Nanosponges are a new paradigm of treatment to block pathological molecules from triggering disease in the body.
‘Rather than creating treatments to block a few specific types of pathological molecules, we are developing a platform that can block a broad spectrum of them and this way we can treat and prevent disease more effectively and efficiently.’
The new nanosponges are nanoparticles of biodegradable polymer coated with the cell membranes of neutrophils, a type of white blood cell.
Neutrophils are among the immune system’s first responders against invading pathogens.
They are also known to play a role in the development of rheumatoid arthritis.
When rheumatoid arthritis develops, cells in the joints produce inflammatory proteins called cytokines.
Release of cytokines signals neutrophils to enter the joints and once there, cytokines bind to receptors on the neutrophil surfaces, activating them to release more cytokines, which in turn draws more neutrophils to the joints and so on.
The nanosponges essentially nip this inflammatory cascade in the bud.
By acting as tiny neutrophil decoys, they intercept cytokines and stop them from signalling even more neutrophils to the joints, reducing inflammation and joint damage.
And they promise an alternative to current treatments such as some monoclonal antibody drugs which have helped patients manage symptoms of the disease.
But they work by neutralizing only specific types of cytokines which is not sufficient to treat the disease because there are so many different types of cytokines and pathological molecules involved.
‘Neutralizing just one or two types might not be as effective,’ Dr Zhang said.
‘So our approach is to take neutrophil cell membranes, which naturally have receptors to bind all these different types of cytokines and use them to manage an entire population of inflammatory molecules.’
First author PhD student Qiangzhe Zhang explained: ‘This strategy removes the need to identify specific cytokines or inflammatory signals in the process.
‘Using entire neutrophil cell membranes, we’re cutting off all these inflammatory signals at once.’
In mouse models of severe rheumatoid arthritis, injecting nanosponges in inflamed joints led to reduced swelling and protected cartilage from further damage.
The nanosponges performed just as well as treatments in which mice were administered a high dose of monoclonal antibodies.
The nanosponges also worked as a preventive treatment when administered prior to inducing the disease in another group of mice.
The study was published in Nature Nanotechnology.