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


METHODS
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.


CONCLUSIONS
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.
Hansch
Andreas
A
Institute of Diagnostic and Interventional Radiology, Friedrich Schiller University of Jena, Bachstrasse 18, D-07743 Jena, Germany. andreas.hansch@med.uni-jena.de
Frey
Oliver
O
Gajda
Mieczyslaw
M
Susanna
Graefe
G
Boettcher
Joachim
J
Bräuer
Rolf
R
Kaiser
Werner A
WA
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D004195:Disease Models, Animal; D008297:Male; D008652:Mesoporphyrins / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology
D008652:Mesoporphyrins; D017319:Photosensitizing Agents; C072269:temoporfin