TY - JOUR
T1 - Optimal photosensitizers for photodynamic therapy of infections should kill bacteria but spare neutrophils
AU - Tanaka, Masamitsu
AU - Kinoshita, Manabu
AU - Yoshihara, Yasuo
AU - Shinomiya, Nariyoshi
AU - Seki, Shuhji
AU - Nemoto, Koichi
AU - Hirayama, Takahiro
AU - Dai, Tianhong
AU - Huang, Liyi
AU - Hamblin, Michael R.
AU - Morimoto, Yuji
PY - 2012/1
Y1 - 2012/1
N2 - Photodynamic therapy (PDT) for localized microbial infections exerts its therapeutic effect both by direct bacterial killing and also by the bactericidal effects of host neutrophils stimulated by PDT. Therefore, PDT-induced damage to neutrophils must be minimized, while direct photoinactivation of bacteria is maintained to maximize the therapeutic efficacy of antimicrobial PDT in vivo. However, there has been no study in which the cytocidal effect of PDT on neutrophils was investigated. In this study, the cytocidal effects of PDT on neutrophils were evaluated using different antimicrobial photosensitizers to find suitable candidate photosensitizers for antimicrobial PDT. PDT on murine peripheral-blood neutrophils was performed in vitro using each photosensitizer at a concentration that exerted a maximum bactericidal effect on methicillin-resistant Staphylococcus aureus, and morphological alteration and viability of neutrophils were studied. Most neutrophils were viable (>80%) after PDT using toluidine blue-O (TB) or methylene blue (MB), while neutrophils showed morphological change and their viabilities were decreased (<70%) after PDT using other photosensitizers (erythrosine B, rose bengal, crystal violet, Photofrin, new methylene blue and Laserphyrin). These results suggest that PDT using TB or MB can preserve host neutrophils while exerting a significant therapeutic effect on in vivo localized microbial infection.
AB - Photodynamic therapy (PDT) for localized microbial infections exerts its therapeutic effect both by direct bacterial killing and also by the bactericidal effects of host neutrophils stimulated by PDT. Therefore, PDT-induced damage to neutrophils must be minimized, while direct photoinactivation of bacteria is maintained to maximize the therapeutic efficacy of antimicrobial PDT in vivo. However, there has been no study in which the cytocidal effect of PDT on neutrophils was investigated. In this study, the cytocidal effects of PDT on neutrophils were evaluated using different antimicrobial photosensitizers to find suitable candidate photosensitizers for antimicrobial PDT. PDT on murine peripheral-blood neutrophils was performed in vitro using each photosensitizer at a concentration that exerted a maximum bactericidal effect on methicillin-resistant Staphylococcus aureus, and morphological alteration and viability of neutrophils were studied. Most neutrophils were viable (>80%) after PDT using toluidine blue-O (TB) or methylene blue (MB), while neutrophils showed morphological change and their viabilities were decreased (<70%) after PDT using other photosensitizers (erythrosine B, rose bengal, crystal violet, Photofrin, new methylene blue and Laserphyrin). These results suggest that PDT using TB or MB can preserve host neutrophils while exerting a significant therapeutic effect on in vivo localized microbial infection.
UR - http://www.scopus.com/inward/record.url?scp=84855346892&partnerID=8YFLogxK
U2 - 10.1111/j.1751-1097.2011.01005.x
DO - 10.1111/j.1751-1097.2011.01005.x
M3 - Article
C2 - 21950417
AN - SCOPUS:84855346892
SN - 0031-8655
VL - 88
SP - 227
EP - 232
JO - Photochemistry and Photobiology
JF - Photochemistry and Photobiology
IS - 1
ER -