Document Detail

Evidence for a bystander role of neutrophils in the response to systemic 5-aminolevulinic acid-based photodynamic therapy.
MedLine Citation:
PMID:  16948825     Owner:  NLM     Status:  MEDLINE    
BACKGROUND/PURPOSE: A significant increase in the number of circulating and tumour neutrophils immediately after therapy was observed while investigating the increase in response of tissues to aminolevulinic acid-based photodynamic therapy (ALA-PDT) using a twofold illumination scheme with a prolonged dark interval. The action of (tumour) neutrophils is an important therapeutic adjunct to the deposition of singlet oxygen within the treatment volume, for many photosensitizers. It is not known if those phagocytes contribute to the improved outcome of ALA-PDT. In this study we investigated the role of neutrophils in the response to PDT using systemic ALA with and without light fractionation. METHODS: Rhabdomyosarcoma, transplanted in the thigh of female WAG/Rij rats were illuminated transdermally using 633 nm light following i.v. administration of 200 mg/kg ALA. The pharmacokinetics of protoporphyrin IX (PpIX) within the tumour tissue during therapy were determined to compare with that observed in other models for topical administration of ALA. PDT was performed under immunologically normal or neutropenic conditions using various illumination schemes. The number of neutrophils in tumour and in the circulation were determined as a function of time after treatment and compared with growth delay of each scheme. RESULTS: Fluorescence spectroscopy revealed similar pharmacokinetics of PpIX to those observed during and after topical ALA-PDT. The number of neutrophils within the illuminated tumour and in the circulation increased significantly following therapy. This increase in the number of neutrophils was associated with an increase in the efficacy of therapy: the more effective the therapy the greater the increase in tumour and blood neutrophils. Administration of anti-granulocyte serum treatment prevented the influx of neutrophils after ALA-PDT, but did not lead to a significant decrease in the efficacy of the PDT treatment on the growth of the tumour for any illumination scheme investigated. CONCLUSION: These results indicate that the magnitude of damage inflicted on the tumour by ALA-PDT does not depend on the presence of neutrophils in the tumour or circulation and that the role of neutrophils in ALA-PDT is much less important than in PDT using other photosensitizers. These data contribute to the understanding of the mechanism of response of tissue to systemic ALA-PDT.
Henriëtte S de Bruijn; Wim Sluiter; Angélique van der Ploeg-van den Heuvel; Henricus J C M Sterenborg; Dominic J Robinson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Photodermatology, photoimmunology & photomedicine     Volume:  22     ISSN:  0905-4383     ISO Abbreviation:  Photodermatol Photoimmunol Photomed     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-04     Completed Date:  2007-01-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9013641     Medline TA:  Photodermatol Photoimmunol Photomed     Country:  Denmark    
Other Details:
Languages:  eng     Pagination:  238-46     Citation Subset:  IM    
Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Erasmus MC, Rotterdam, The Netherlands.
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MeSH Terms
Aminolevulinic Acid / administration & dosage,  pharmacokinetics,  pharmacology*
Infusions, Intravenous
Neutrophils / drug effects*
Photosensitizing Agents / administration & dosage,  pharmacokinetics,  pharmacology*
Rhabdomyosarcoma / drug therapy*,  metabolism,  pathology
Skin Neoplasms / drug therapy*,  metabolism,  pathology
Spectrometry, Fluorescence
Transplantation, Heterologous
Reg. No./Substance:
0/Photosensitizing Agents; 106-60-5/Aminolevulinic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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