Non-homogeneous liver distribution of photosensitizer and its consequence for photodynamic therapy outcome
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2010
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Resumo |
Background: Photodynamic therapy is mainly used for treatment of malignant lesions, and is based on selective location of a photosensitizer in the tumor tissue, followed by light at wavelengths matching the photosensitizer absorption spectrum. In molecular oxygen presence, reactive oxygen species are generated, inducing cells to die. One of the limitations of photodynamic therapy is the variability of photosensitizer concentration observed in systemically photosensitized tissues, mainly due to differences of the tissue architecture, cell lines, and pharmacokinetics. This study aim was to demonstrate the spatial distribution of a hematoporphyrin derivative, Photogem(R), in the healthy liver tissue of Wistar rats via fluorescence spectroscopy, and to understand its implications on photodynamic response. Methods: Fifteen male Wistar rats were intravenously photosensitized with 1.5 mg/kg body weight of Photogem(R). Laser-induced fluorescence spectroscopy at 532nm-excitation was performed on ex vivo liver slices. The influence of photosensitizer surface distribution detected by fluorescence and the induced depth of necrosis were investigated in five animals. Results: Photosensitizer distribution on rat liver showed to be greatly non-homogeneous. This may affect photodynamic therapy response as shown in the results of depth of necrosis. Conclusions: As a consequence of these results, this study suggests that photosensitizer surface spatial distribution should be taken into account in photodynamic therapy dosimetry, as this will help to better predict clinical results. (C) 2010 Elsevier B.V. All rights reserved. Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) FAPESP - Brazil Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) CAPES-Brazil Brazilian National Council for Scientific and Technological Development (CNPq-Brazil) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) |
Identificador |
PHOTODIAGNOSIS AND PHOTODYNAMIC THERAPY, v.7, n.3, p.189-200, 2010 1572-1000 http://producao.usp.br/handle/BDPI/29864 10.1016/j.pdpdt.2010.07.002 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCIENCE BV |
Relação |
Photodiagnosis and Photodynamic Therapy |
Direitos |
restrictedAccess Copyright ELSEVIER SCIENCE BV |
Palavras-Chave | #Photodynamic therapy #Photosensitizer #Dosimetry #Fluorescence #Liver #NORMAL RAT-LIVER #IN-VIVO #PROTOPORPHYRIN-IX #HUMAN PROSTATE #FLUORESCENCE #PHARMACOKINETICS #TUMORS #LIGHT #SPECTROSCOPY #TISSUE #Oncology |
Tipo |
article original article publishedVersion |