Arthrosetherapie: Optimierung von osteochondralen allogenen Transplantaten mittels 5-Aminolävulinat basierter photodynamischer Therapie
Final Report Abstract
Outcome in osteochondral allografting is limited by immune-logical incompatibility of bone. Based on the described resistance of cartilage to photodynamic therapy it is hypothesized that pretreatment of allografts by 5-aminolevulinic acid based photodynamic therapy (5-ALA- PDT) prior to transplantation may devitalize bone selectively while chondrocytes remain viable. Chondrocytes, osteoblasts and osteochondral tissues were harvested from porcine humeral heads. To assess cytotoxic effects of 5-ALA-PDT (5-20J/cm2, 100mW/cm2) on (I) chondrocytes and osteoblasts the MTT-assay and on (II) osteochondral tissues in situ hybridization (collagen type I and type II mRNA for functional osteoblasts and chondrocytes, respectively) were used. Cell survival after 5-ALA-PDT was higher for chondrocytes (5J/cm2: 87±12% compared to untreated cells) than for osteoblasts (5J/cm2: 12±11 %). The percentage of functional chondrocytes in cartilage showed a decrease after 5-ALA-PDT (direct fixation: 92±2%, 20J/cm2: 35±15%; p<0.001). A significant decrease in the percentage of bone surfaces covered with functional osteoblasts was observed from freshly harvested (31±3%) to untreated tissues maintained in culture (11±4%, p=0.005), without further decrease to 5-ALA-PDT treated tissues (8±3%). Chondrocytes were more resistant to 5-ALA-PDT than osteoblasts in cell culture, while in tissue culture a loss of functional chondrocytes was observed after 5-ALA-PDT. As osteoblasts but not chondrocytes were sensitive to the applied tissue culture conditions a devitalized bone with functional cartilage could already be achieved by applying specific tissue culture conditions even without 5-ALA-PDT.
Publications
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5-Aminolaevulinic Acid Based Photodynamic Therapy Causes an Inactivation of Chondrocytes but not of Bone Cells in Osteochondral Grafts. World Congress on Osteoarthritis, OARSI, Praha, Czech Rebulic, 2006
Bastian JD, Egli RJ, Ganz R, Hofstetter W, Leunig M
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Influence of Culture Conditions in the Assessment of Pretreatment Effects in Osteochondral Allografts. SGO/SSO Congress, Luzern, 2006
Bastian JD, Egli RJ, Ganz R, Hofstetter W, Leunig M
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Storage Conditions are Crucial to Maintain Phenotypes in Osteochondral Grafts. Frontiers of Skeletal Biology, 11th Workshop on Cell Biology of Bone and Cartilage in Health and Disease, Davos, Switzerland, 2006
Bastian JD, Egli RJ, Ganz R, Hofstetter W, Leunig M
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5-Aminolaevulinic Acid Based Photodynamic Therapy (5-ALA-PDT) causes an Inactivation of Chondrocytes but not of Bone Cells in Osteochondral Grafts. 24. Kongress der Deutschsprachigen Arbeitsgemeinschaft für Arthroskopie (AGA), Köln, 2007
Bastian JD, Egli RJ, Ganz R, Hofstetter W, Leunig M
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5-Aminolaevulinic Acid Based Photodynamic Therapy Causes an Inactivation of Chondrocytes but not of Bone Cells in Osteochondral Grafts. 8th EFORT Congress, Florenz, Italy, 2007
Bastian JD, Egli RJ, Ganz R, Hofstetter W, Leunig M
