Comparative Study on Cartilage Tissue Collected From Less- and Severely-Affected Region of Osteoarthritic Knee

Culture expanded chondrocytes isolated from non-load bearing region of osteoarthritic (OA) joint has been used to construct tissue engineered cartilage for treatment purposes. The aim of the study was to compare the histological properties of the cartilage tissue and morphological properties of the chondrocytes isolated from less and severely affected OA knee. Human articular cartilage was obtained as redundant tissue from consented patients with late-stage OA undergoing total knee replacement surgery at Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Articular cartilage was graded according to Dougados and Osteoarthritis Research Society International (OARSI) classification. Articular cartilage was classified into less affected (LA; Grade 0-1) and severely affected (SA; Grade 2-3). Cartilage tissue from less and severely affected region was stained with Safranin O staining. Isolated chondrocytes from each group were cultured until passage 4 (P4). Their growth patterns, cell areas, and circularity were compared. LA-cartilage tissue shows uniform spread of safranin O staining indicating intact extracellular matrix (ECM) component. However, SA-cartilage shows significant reduction and unstable staining due to its degraded ECM. LA-chondrocytes showed an aggregated growth compared to SA-chondrocyte that remains monolayer. Moreover, LA-chondrocytes have significantly higher cell area with wider spreading at passage 0 and 4 compared to SA-chondrocytes. It was also found that chondrocyte circularity increased with passage, and circularity of LA-chondrocytes was significantly higher than that of the SA-chondrocytes at passage 3. This study demonstrated the considerable difference in the cellular properties for less and severely affected chondrocytes and implication of these differences in cell-based therapy needed to be explored.

Sciatic nerve repair with tissue engineered nerve: Olfactory ensheathing cells seeded poly(lactic-co-glygolic acid) conduit in an animal model.

BACKGROUND AND AIM: Synthetic nerve conduits have been sought for repair of nerve defects as the autologous nerve grafts causes donor site morbidity and possess other drawbacks. Many strategies have been investigated to improve nerve regeneration through synthetic nerve guided conduits. Olfactory ensheathing cells (OECs) that share both Schwann cell and astrocytic characteristics have been shown to promote axonal regeneration after transplantation. The present study was driven by the hypothesis that tissue-engineered poly(lactic-co-glycolic acid) (PLGA) seeded with OECs would improve peripheral nerve regeneration in a long sciatic nerve defect. MATERIALS AND METHODS: Sciatic nerve gap of 15 mm was created in six adult female Sprague-Dawley rats and implanted with PLGA seeded with OECs. The nerve regeneration was assessed electrophysiologically at 2, 4 and 6 weeks following implantation. Histopathological examination, scanning electron microscopic (SEM) examination and immunohistochemical analysis were performed at the end of the study. RESULTS: Nerve conduction studies revealed a significant improvement of nerve conduction velocities whereby the mean nerve conduction velocity increases from 4.2 ΁ 0.4 m/s at week 2 to 27.3 ΁ 5.7 m/s at week 6 post-implantation (P < 0.0001). Histological analysis revealed presence of spindle-shaped cells. Immunohistochemical analysis further demonstrated the expression of S100 protein in both cell nucleus and the cytoplasm in these cells, hence confirming their Schwann-cell-like property. Under SEM, these cells were found to be actively secreting extracellular matrix. CONCLUSION: Tissue-engineered PLGA conduit seeded with OECs provided a permissive environment to facilitate nerve regeneration in a small animal model.