With nearly 90% of people over 65 being affected by arthritis, the joint disease is widespread to say the least. It is a degenerative disease where the cartilage in the joint provides a protective layer on bones, but it degenerates over time. It is a particularly painful inflammatory disease that can affect all joints in the body. Current treatments include anti-inflammatory drugs and painkillers mainly address symptoms and not the progress of the disease. Many with severe arthritis turn to joint replacement surgery.
Researchers have successfully identified a substance with the potential to halt cartilage degeneration. And, get this, it a substance extracted from the stems of brown algae. It is similar to specific extracellular biomolecules in cartilage.
The researchers, led by ETHZ researcher Marcy Zenobi-Wong and Empa researcher Katharina Maniura, together with SINTEF in Norway, chemically modified the alginate with sulfate groups and then added it in dissolved form to cell cultures to examine the reaction of various cell types to the modified polysaccharide. This revealed that alginate sulfate can significantly reduce oxidative stress, which is a frequent cause of cell damage or even cell death, and the more sulfate groups attached to the alginate molecule, the greater this reduction.
In laboratory tests, the team led by in identifying a substance with the potential to halt cartilage degeneration in joints. This substance is the polysaccharide alginate extracted from the stems of brown algae – or more precisely cuvie (Lat. Laminaria hyperborea).
Alginate sulfate was also able to suppress the inflammatory reaction, again depending on the number of sulfate groups, and was able to down-regulate the expression of genes that trigger an inflammatory reaction in both human cartilage cells, known as chondrocytes, and in macrophages, the “scavenger cells” of our immune system. The algal molecules should therefore slow down cartilage degeneration. “The hope is that they can even stop this degeneration,” says Empa researcher Markus Rottmar.
The alginate sulfates have so far only been tested in vitro, i.e. in the laboratory with cell cultures. However, the encouraging results mean that research will now continue. The next stage is to test the substances on animals. If this is also successful, clinical trials can then be conducted on people. These tests are, however, laborious and time-consuming. If everything were to work perfectly, it would still be a few years before arthritis patients could be treated with alginate sulfate.