Cited by 173Photodynamic Therapy Research StudiesNanoplatforms for cancer theranosticsGlioma Diagnosis and Treatment

Metronomic Photodynamic Therapy as a New Paradigm for Photodynamic Therapy: Rationale and Preclinical Evaluation of Technical Feasibility for Treating Malignant Brain Tumors¶

Bisland, Stuart K., Lilge, Lothar, Lin, Annie, Rusnov, Robert, Wilson, Brian C.·2004·Photochemistry and Photobiology

Abstract

The concept of metronomic photodynamic therapy (mPDT) is presented, in which both the photosensitizer and light are delivered continuously at low rates for extended periods of time to increase selective tumor cell kill through apoptosis. The focus of the present preclinical study is on mPDT treatment of malignant brain tumors, in which selectivity tumor cell killing versus damage to normal brain is critical. Previous studies have shown that low-dose PDT using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) can induce apoptosis in tumor cells without causing necrosis in either tumor or normal brain tissue or apoptosis in the latter. On the basis of the levels of apoptosis achieved and model calculations of brain tumor growth rates, metronomic delivery or multiple PDT treatments, such as hyperfractionation, are likely required to produce enough tumor cell kill to be an effective therapy. In vitro studies confirm that ALA-mPDT induces a higher incidence of apoptotic (terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate, sodium salt nick-end labeling positive) cells as compared with an acute, high-dose regimen (ALA-aPDT). In vivo, mPDT poses two substantial technical challenges: extended delivery of ALA and implantation of devices for extended light delivery while allowing unencumbered movement. In rat models, ALA administration via the drinking water has been accomplished at very high doses (up to 10 times therapeutic dose) for up to 10 days, and ex vivo spectrofluorimetry of tumor (9L gliosarcoma) and normal brain demonstrates a 3-4 fold increase in the tumor-to-brain ratio of PpIX concentration, without evidence of toxicity. After mPDT treatment, histological staining reveals extensive apoptosis within the tumor periphery and surrounding microinvading colonies that is not evident in normal brain or tumor before treatment. Prototype light sources and delivery devices were found to be practical, either using a laser diode or light-emitting diode (LED) coupled to an implanted optical fiber in the rat model or a directly implanted LED using a rabbit model. The combined delivery of both drug and light during an extended period, without compromising survival of the animals, is demonstrated. Preliminary evidence of selective apoptosis of tumor under these conditions is presented.

Integrity signals

Registry

Crossref · 10.1562/2004-03-05-ra-100.1

Cites

39 of 39 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

We couldn’t retrieve this paper’s full text, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Bisland, S. K., Lilge, L., Lin, A., Rusnov, R., & Wilson, B. C.
Affiliations
University Health Network (CA)
Venue
Photochemistry and Photobiology
Publisher
Wiley
Published
2004
Volume
80
Issue
1
Pages
22
ISSN
0031-8655 (ISSN-L)
OpenAlex
W2065744257
Cited by
173
References
39
Citations by year
2025: 1 · 2024: 8 · 2023: 10 · 2022: 5 · 2021: 7 · 2020: 12 · 2019: 7 · 2018: 7 · 2017: 4 · 2016: 10 · 2015: 5 · 2014: 16 · 2013: 4 · 2012: 7
FWCI
8.68
Type
journal article
Language
en
Open access
closed
Locations
  • Photochemistry and Photobiology (publishedVersion)
  • PubMed (publishedVersion)
  • BioOne Complete (BioOne) (submittedVersion)
Funders
National Cancer Institute (P01 CA43892, P01CA043892)
Topics
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Photodynamic Therapy Research Studies
  • Physical Sciences › Engineering › Biomedical Engineering › Nanoplatforms for cancer theranostics
  • Health Sciences › Medicine › Genetics › Glioma Diagnosis and Treatment
Keywords
malignant brain tumors, 5-aminolevulinic acid, protoporphyrin IX, apoptosis, hyperfractionated radiotherapy, 9L gliosarcoma, tumor growth modeling, fluorescence spectroscopy
MeSH terms
Brain Neoplasms, Clinical Trials as Topic, Humans, Photochemotherapy, Apoptosis

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review