title: Interstitial photodynamic therapy and glioblastoma: Light fractionation in a preclinical model.
abstract: 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.
  
  
  
  To evaluate the efficiency of two light-fractionation schemes using immunohistological data.
  
  
  
  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.
  
  
  
  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).
  
  
  
  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.
authors.affiliation: Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000, Lille, France.|Department of Neurosurgery, CHU Lille, F-59000, Lille, France.
authors.forename: Henri-Arthur
authors.initials: HA
authors.lastname: Leroy
authors.affiliation: Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000, Lille, France.|Department of Neurosurgery, CHU Lille, F-59000, Lille, France.
authors.forename: Maximilien
authors.initials: M
authors.lastname: Vermandel
authors.affiliation: Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000, Lille, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Vignion-Dewalle
authors.affiliation: Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000, Lille, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Leroux
authors.affiliation: Department of Neuropathology, CHU Lille, F-59000, Li, lle, France.
authors.forename: Claude-Alain
authors.initials: CA
authors.lastname: Maurage
authors.affiliation: Department of Biostatistics, CHU Lille, EA2694, Université de Lille, F-59000, Lille, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Duhamel
authors.affiliation: Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000, Lille, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Mordon
authors.affiliation: Univ. Lille, Inserm, CHU Lille, U1189 - ONCO-THAI - Image Assisted Laser Therapy for Oncology, F-59000, Lille, France.|Department of Neurosurgery, CHU Lille, F-59000, Lille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Reyns
mesh_terms: D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D000818:Animals; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000473:pathology; D004195:Disease Models, Animal; D019583:Dose Fractionation, Radiation; D005909:Glioblastoma / Q000188:drug therapy* / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D051381:Rats; D011923:Rats, Nude
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid
keywords: 5-ALA; U87; glioblastoma; immunohistology; photodynamic therapy