Algae could be a new ally in the fight against arthritis

24 Aug 2017 --- A group of researchers at ETH Zurich, Empa and the Norwegian research institute SINTEF are investigating the possibilities of using algae to treat arthritis, based on a polysaccharide, a long-chain sugar molecule, originating from brown algae. When chemically modified, this “alginate” reduces oxidative stress, has an anti-inflammatory effect in cell culture tests and suppresses the immune reaction against cartilage cells, thereby combating the causes of arthritis.

Arthritis affects around 90 percent of all people over 65 to varying degrees, but this degenerative disease is also widespread amongst younger people. In arthritis, the cartilage in the joint, a type of protective layer on bones that “lubricates” the joint, degenerates over time. This can be extremely painful for sufferers because inflammatory reactions are associated with cartilage degeneration.

Arthritis can affect all joints in the body, but most often affects the knee joint, hip joint and fingers. The disease has been considered incurable until now. Current treatment methods, such as anti-inflammatory drugs and painkillers, mainly address the symptoms. Often, the only remaining option is an operation to replace the affected joint with an artificial one.
In laboratory tests, the team led by ETHZ researcher Marcy Zenobi-Wong and Empa researcher Katharina Maniura has now succeeded 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), which is similar to specific extracellular biomolecules in cartilage. The researchers 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 could 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.

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.