Use of native Mesenchymal Stromal Cells from the knee joint towards regenerating articular cartilage.

The existing technique for the use of stem cell based therapies for joint repair are based on time-consuming laboratory culture expansion protocols that are also expensive. The purpose of this thesis was to devise ways to exploit the discovery of synovial fluid mesenchymal stromal cells (MSC) towards the cost effective development of one stage cellular therapy development for knee osteoarthritis (OA). This work is based on the hypothesis that synovial fluid (SF) MSC that originate from the synovium, can be greatly increased in the joint cavity using a novel device. Secondly, it was hypothesised that knowledge of the joint in vivo environment following a microfracture procedure could be used to facilitate MSC adherence to, and migration towards a biological scaffold, similar to a microfracture, as a first step towards novel cartilage regeneration therapy development. First, a MSC releasing device was developed for effective cell release and minimal entrapment within the device. Secondly, using biological scaffolds, in an in vitro model, MSC were capable of adhering to, and migrating toward the scaffold, and that the scaffold composition could play an important function on migration. Finally it was shown that standard joint arthroscopy, washes resident joint fluid MSC away. It was then demonstrated in the laboratory that synovial brushing does indeed release cells that have the MSC immunophentype (CD73, CD90, CD105) following culture expansion. In addition, released MSC demonstrated good chondrogenic, adipogenic and osteogenic potentials, further endorsing their use for articular cartilage repair. A prototype device was tested in humans and was shown to significantly increase fluid MSC in vivo in man. The thesis findings, demonstrate MSC augmentation, which provides the basis of testing novel regenerative strategies, from bench to operating theatre in orthopaedics, and supports the objective of a one stage cost effective procedure for joint repair.