Research published in the Biomacromolecules journal has shown that the unique structure of microcapsules could help deliver specific proteins directly into cartilage to reduce inflammation and even reverse tissue damage caused by the disease.
The C-type natriuretic peptide (CNP) occurs naturally in the body and acts as an anti-inflammatory and helps boost repair of damaged tissue.
Scientists have long believed that this has the potential to repair damaged cartilage in people with osteoarthritis. But using it in treatment for the disease has been difficult, as the protein is rapidly broken down by hydrolysis within cartilage tissue, rendering any attempts at therapy largely useless.
In an effort to deliver the protein in an effective way, researchers from the University of London loaded the CNP into calcium carbonate (CaCO3) particles to form ‘microcapsules’.
These microcapsules measure between 2-3µm and ‘can easily be injected by GPs’ into the affected cartilage of osteoarthritis patients, the researchers said.
Folded pancake structure
CaCO3 particles have a ‘folded pancake structure’, meaning they can be loaded with multiple layers of CNP despite their microscopic size.
The multilayered structure allows the CNP to be released gradually and in a controlled manner, fixing previous problems where it was broken down too quickly to provide much of a benefit.
In a further round of experiments, the researchers injected these into in vitro cartilage samples taken from cows. They found that the microcapsules had ‘potent anti-inflammatory’ effects, suggesting they present a clinically effective method of delivering CNP to cartilage tissue.
The results suggest that injections of microcapsules could be used to heal damaged cartilage and reduce inflammation in people with osteoarthritis in the future.
Lead author of the study Dr Tina Chowdhury, said: ‘If this method can be transferred to patients it could drastically slow the progression of osteoarthritis and even begin to repair damaged tissue.
‘CNP is currently available to treat other conditions such as skeletal diseases and cardiovascular repair. If we could design simple injections using the microcapsules, this means the technology has the potential to be an effective and relatively cheap treatment that could be delivered in the clinic or at home.’