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Interstitial photodynamic therapy and glioblastoma: Light fractionation in a preclinical model
Author(s) -
Leroy HenriArthur,
Vermandel Maximilien,
VignionDewalle AnneSophie,
Leroux Bertrand,
Maurage ClaudeAlain,
Duhamel Alain,
Mordon Serge,
Reyns Nicolas
Publication year - 2017
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.22620
Subject(s) - photodynamic therapy , photosensitizer , medicine , glioblastoma , pathology , infiltration (hvac) , cytotoxic t cell , apoptosis , glioma , nuclear medicine , in vitro , cancer research , chemistry , biochemistry , organic chemistry , physics , thermodynamics
Background Glioblastoma is a high‐grade cerebral tumor with local recurrence and poor outcome. Photodynamic therapy (PDT) is a localized treatment based on the light activation of a photosensitizer (PS) in the presence of oxygen, which results in the formation of cytotoxic species. The delivery of fractionated light may enhance treatment efficacy by reoxygenating tissues. Objective To evaluate the efficiency of two light‐fractionation schemes using immunohistological data. Materials and Methods Human U87 cells were grafted into the right putamen of 39 nude rats. After PS precursor intake (5‐ALA), an optic fiber was introduced into the tumor. The rats were randomly divided into three groups: without light, with light split into 2 fractions and with light split into 5 fractions. Treatment effects were assessed using brain immunohistology. Results Fractionated treatments induced intratumoral necrosis ( P < 0.001) and peritumoral edema ( P = 0.009) associated with a macrophagic infiltration ( P = 0.006). The ratio of apoptotic cells was higher in the 5‐fraction group than in either the sham ( P = 0.024) or 2‐fraction group ( P = 0.01). Peripheral vascularization increased after treatment ( P = 0.017), and these likely new vessels were more frequently observed in the 5‐fraction group ( P = 0.028). Conclusion Interstitial PDT with fractionated light resulted in specific tumoral lesions. The 5‐fraction scheme induced more apoptosis but led to greater peripheral neovascularization. Lasers Surg. Med. 49:506–515, 2017. © 2016 Wiley Periodicals, Inc.