Photodynamic treatment as a novel approach in the therapy of arthritic joints

✍ Scribed by Andreas Hansch; Oliver Frey; Mieczyslaw Gajda; Graefe Susanna; Joachim Boettcher; Rolf Bräuer; Werner A. Kaiser

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 203 KB
• Volume: 40
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.20620

✦ Synopsis

Abstract

Background and Objective

Minimal invasive local treatment of joints is a desirable option in the therapy of rheumatoid arthritis (RA). Aim of this study was to evaluate the effects of photodynamic treatment (PDT) with different doses of the photosensitizer meta‐tetra(hydroxyphenyl)chlorin (m‐THPC; or temoporfin) in a murine model of RA (antigen‐induced arthritis, AIA).

Methods In vivo distribution

The distribution of native and liposomal m‐THPC (including a formulation with polyethylene glycol [PEG] coating) was assessed by fluorescence spectrometry in arthritic joints, normal joints, and skin.

Treatment

AIA mice received different concentrations of pegylated liposomal m‐THPC (0.1, 0.05, 0.01, or 0.005 mg/kg body weight; n = 5 per group) and subjected to PDT with a laser system 12 hours post‐injection of the photosensitizer. Treatment effects were evaluated histologically in comparison to untreated AIA (n = 5).

Results

Pegylated liposomal m‐THPC showed the most favorable accumulation in arthritic joints compared to native m‐THPC and to non‐peg‐liposomal m‐THPC, therefore it was selected as photosensitizer for PDT treatment. In comparison to untreated AIA, PDT reduced the arthritic score with all doses of pegylated liposomal m‐THPC; statistical significant effects were obtained with doses of 0.05 and 0.01 mg/kg.

Conclusion

Our study demonstrated that local PDT of arthritic joints is feasible. Application of pegylated liposomal m‐THPC for PDT resulted in significant reduction of arthritis scores. Lasers Surg. Med. 40:265–272, 2008. © 2008 Wiley‐Liss, Inc.