Chondroitin sulfate is an important structural component of cartilage and is naturally found in connective tissues in the human body and in animal cartilage. It is part of a protein molecule that helps give cartilage its elastic properties and is thought to have an anti-inflammatory effect, which can help reduce swelling in the joints. It has been used as a dietary supplement for treating osteoarthritis. Currently, it is sourced from cow trachea. Envisioning an animal-free drug supply, researchers at Rensselaer Polytechnic Institute have modified E. coli to produce chondroitin sulfate.