The objective of the study by Frédéric Oprenyeszk and the UROC team was to try to find a way to regenerate this “lubricant”, to supply it with the elements necessary for its regeneration. To do this, it was necessary to develop a gel which could be substituted for the synovial fluid that is naturally present in the joints. This resulted in microscopic beads made from plant-sourced chitosan.

Chitosan is a glycosaminoglycan rich in glucosamine. Its properties are remarkable: it is a buoyant and bioadhesive compound which means it can “adhere” to other tissues. There are two types of chitosan: it can be animal or plant-based. Animal-sourced chitosan is the most widely used commercially. It is taken from the shells of crustaceans such as prawns or squid(4) Plant-based chitosan is less widely used and is extracted from the stems of button mushrooms which makes this a very accessible source! It is no surprise that this method of obtaining chitosan is preferred by the Liege researchers. Professor Henrotin explains, “Firstly, it represents a new way of doing things. Secondly, it is hypoallergenic, plant-based chitosan does not contain contaminants which can cause inflammatory or infectious reactions in the joint. Thirdly, it is a much more accessible and inexhaustible source. We are no longer confronted by the constraints linked to chitosan extraction from crustaceans which only allows for average levels of purity”. Significantly, one of the only producers of vegetable-sourced chitosan in the world, KitoZyme, is located in Liege (its biomedical activities have been transferred to Synolyne Pharma, a spin-off of the University of Liege). It was the perfect opportunity to create an interaction between the academic world and industry and it proved very successful(5).

When they come into contact with chitosan, diseased cells are treated

Central to the in vitro research carried out by Frédéric Oprenyeszk was a procedure patented by UROC: A matrix composed of alginate and enriched with chitosan in which diseases human cells known as chondrocytes, were encapsulated. The mixture of alginate and chitosan forms beads in which diseased cells were grown in culture for a period of 28 days either in chitosan or alginate beads. The purpose of this procedure was to demonstrate the added value of chitosan. Frédéric Oprenyeszk explains the procedure used in detail: “We began a process of cartilage digestion using enzymes that “break up” the cartilage and release the cells. These were then added to the chitosan alginate mixture and this mixture was then incorporated into a solution resulting in gelation which in turn resulted in the production of composites that were incorporated into chitosan alginate beads”. This is the patented procedure. “We are the first to succeed in creating chitosan beads into which cells can be introduced and brought into contact with the chitosan molecules”.

(3) In 2003, there were around 65 producers of chitosan in the world. The great majority of them (93%) produce animal-sourced chitosan. This is a rapidly growing market because of the numerous applications of chitosan. For example, it seems to be a “fat binder”, which is the reason why it is sold in the form of a pill for weight-loss. Chitosan can also act as fibre for digestion, as a preservative or even as an anti-bacterial agent. There is therefore no shortage of industrial possibilities for the product.
(4)Synolyne Pharma has its own GMP area (Good Manufacturing Practices), a necessary prelude to clinical trials. The company has the capability to produce chitosan, gels hydrogels and plant-based chitosan