L. Selvaratnam

Tendon is a dense connective tissue that connects muscle to bone. Tendon can adapt to mechanical forces passing across it, through a reciprocal relationship between its cellular components (tenocytes and tenoblasts) and the extracellular matrix (ECM). In early development, the formation of scleraxis-expressing tendon progenitor population in the sclerotome is induced by a fibroblast growth factor signal secreted by the myotome. Tendon injury has been defined as a loss of cells or ECM caused by trauma. It represents a failure of cells and matrix adaptation to mechanical loading. Injury initiates attempts of tendon to repair itself, which has been defined as replacement of damaged or lost cells and ECM by new cells or new matrices. Tendon healing generally consists of four different phases: the inflammatory, proliferation, differentiation and remodelling phases. Clinically, tendons are repaired with a variety of surgical techniques, which show various degrees of success. In order to improve the conventional tendon repair methods, current tendon tissue engineering aims to investigate a repair method which can restore tissue defects with living cells, or cell based therapy. Advances in tissue engineering techniques would potentially yield to a cell-based product that could regenerate functional tendon tissue.

Although mesenchymal stem cells (MSCs) isolation from a number of tissue sources have been described, very few literatures have been reported successful isolation of adult MSCs from peripheral blood or its chondrogenic differentiation for clinical applications. The objective of this study is to isolate MSCs derived from both human bone marrow and peripheral blood and to compare their potential to undergo chondrogenesis.

To evaluate the ability of autologous chondrocyte transplantation to repair articular cartilage defects, autologous chondrocytes embedded in alginate beads were implanted in focal cartilage defects created in 9 New Zealand white rabbits. After 4 weeks of cartilage damage, the right knee was repaired via autologous chondrocyte-alginate constructs transplantation and the left knee was left untreated (control group). The quality of cartilage tissues of both knees was then compared at 3 months following the procedure, as reflected by the ...

To compare the efficacy of autologous chondrocyte transplantation (ACT) versus non-operative measures for cartilage repair in rabbits. Nine New Zealand white rabbits were used. Identical focal defects were created in the articular cartilage of both knees. One month later, the right knee was repaired via ACT, while the left knee was left untreated (control group). The quality of cartilage tissues in both knees was compared 3 months later, according to the quantitative analysis of glycosaminoglycan (GAG) in the cartilage and macroscopic examination of histology using the Brittberg/International Cartilage Research Society (ICRS) score. Microscopic examination showed enhanced regeneration following ACT repair. Quantification analysis revealed significantly higher cellular expression of GAG in the ACT-treated knees (1.12 vs 0.81 microgram GAGs/mg protein, p=0.008). The mean Brittberg/ICRS score was significantly higher in the treated knees (6.00 vs 1.89, p=0.007). ACT is superior to non-...

The effects of Glucosamine Sulphate (GS) and Chondroitin Sulphate (CS) on the healing of damaged and repaired articular cartilage were investigated. This study was conducted using 18 New Zealand white rabbits as experimental models. Focal cartilage defects, surgically created in the medial femoral condyle, were either treated by means of autologous chondrocyte implantation (ACI) or left untreated as controls. Rabbits were then divided into groups which received either GS+/-CS or no pharmacotherapy. Three rabbits from each group were sacrificed at 12 and 24 weeks post-surgery. Knees dissected from rabbits were then evaluated using gross quantification of repair tissue, glycosaminoglycan (GAG) assays, immunoassays and histological assessments. It was observed that, in contrast to untreated sites, surfaces of the ACI-repaired sites appeared smooth and continuous with the surrounding native cartilage. Histological examination demonstrated a typical hyaline cartilage structure; with prot...

In view of poor regeneration potential of the articular cartilage, in-vitro engineering of cartilage tissue offers a promising option for progressive joint disease. This study aims to develop a biologically engineered articular cartilage for autologous transplantation. The initial work involved determination of chondrocyte yield and viability, and morphological analysis. Cartilage was harvested from the knee, hip and shoulder joints of adult New Zealand white rabbits and chondrocytes were isolated by enzymatic digestion of the extra-cellular matrix before serial cultivation in DMEM/Ham's F12 media as monolayer cultures. No differences were noted in cell yield. Although chondrocytes viability was optimal (>93%) following harvest from native cartilage, their viability tended to be lowered on passaging. Chondrocytes aggregated in isogenous colonies comprising ovoid cells with intimate intracellular contacts and readily exhibited Safranin-O positive matrix; features typically ass...