Significantly increased lesion size by using the near-infrared photosensitizer 5,10,15,20-tetrakis (m-hydroxyphenyl)bacteriochlorin in interstitial photodynamic therapy of normal rat liver tissue.
OBJECTIVE
Penetration of tissues by activating light ultimately limits the size of the lesions achievable in interstitial photodynamic therapy. Measurements of the wavelength-dependence of tissue optical properties suggest that substantial improvements may be possible, particularly in pigmented organs such as the liver, by using drugs absorbing at near infrared wavelengths.


METHODS
In this study, the extent of light induced necrosis with the photosensitive agents Photofrin (activated at 632 nm), meta-tetra(hydroxyphenyl)chlorin (mTHPC) (activated at 652 nm) and 5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin (mTHPBC) (activated at 740 nm) are compared in normal rat liver. Interstitial irradiation of mTHPBC-sensitized liver tissue resulted in significantly larger necrotic areas than irradiation of Photofrin and mTHPC-sensitised livers.


CONCLUSIONS
The results illustrate the advantage of near-infrared photosensitizer activation and point to a specific role for mTHPBC in the interstitial treatment of liver tumours.
Rovers
J P
JP
Academic Department of Surgery, St. Bartholomew's and The Royal London Hospital School of Medicine & Dentistry, Whitechapel, London, United Kingdom.
de Jode
M L
ML
Grahn
M F
MF
D000818:Animals; D017323:Dihematoporphyrin Ether / Q000627:therapeutic use; D053685:Laser Therapy; D008099:Liver / Q000473:pathology*; D008297:Male; D008652:Mesoporphyrins / Q000627:therapeutic use; D009336:Necrosis; D010778:Photochemotherapy / Q000009:adverse effects* / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000627:therapeutic use*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
C414352:5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin; D008652:Mesoporphyrins; D017319:Photosensitizing Agents; D011166:Porphyrins; D017323:Dihematoporphyrin Ether; C072269:temoporfin