2 April 1996 Protoporphyrin IX distribution after intra-articular and systemic application of 5-aminolevulinic acid in healthy and arthritic joints
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Abstract
Arthroscopic synovectomy, which is limited today to the large joints, is an important early treatment of rheumatoid arthritis (RA). Photodynamic therapy (PDT) is potentially to be a less invasive method of removing the synovial membrane. Therefore, in a rabbit model of RA, the accumulation of the photosensitizer Protoporphyrin IX (PPIX) after intra-articular and systemic application of ALA into arthritic rabbit knee joints was studied in skin, patella, synovial tissue, and meniscus by fluorescence microscopy. PPIX fluorescence was measured in biopsies taken at different times after application of neutral and acid ALA solutions. Significant PPIX fluorescence was observed in the synovial membrane and skin 2 and 4 hours after application. Using intra-articular application, ALA solutions prepared with pH 5.5 were at least as efficient as neutral solutions in sensitizing the synovial membrane. Skin also showed PPIX within 4 hours after application. After 24 hours, a marginal PPIX fluorescence was detected in these tissues. On the other hand, in cartilage and meniscus significant PPIX accumulation was still observed 24 hours after ALA injection. Systemic application of ALA also showed a good accumulation of PPIX. Further experiments are needed to show whether accumulation of the photosensitizer and tissue selectivity are sufficient for a successful treatment of rheumatoid synovitis.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gereon Huettmann, Gereon Huettmann, Christian Hendrich, Christian Hendrich, Reginald Birngruber, Reginald Birngruber, Christiane Lehnert, Christiane Lehnert, Jose Seara, Jose Seara, Werner E. Siebert, Werner E. Siebert, Heyke Cacile Diddens, Heyke Cacile Diddens, "Protoporphyrin IX distribution after intra-articular and systemic application of 5-aminolevulinic acid in healthy and arthritic joints", Proc. SPIE 2675, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy V, (2 April 1996); doi: 10.1117/12.237543; https://doi.org/10.1117/12.237543
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