Protoporphyrin IX fluorescence photobleaching is a useful tool to predict the response of rat ovarian cancer following hexaminolevulinate photodynamic therapy

ArticleinLasers in Surgery and Medicine 40(5):332-41 · July 2008with4 Reads
Impact Factor: 2.62 · DOI: 10.1002/lsm.20629 · Source: PubMed

Accurate dosimetry was shown to be critical to achieve effective photodynamic therapy (PDT). This study aimed to assess the reliability of in vivo protoporphyrin IX (PpIX) fluorescence photobleaching as a predictive tool of the hexaminolevulinate PDT (HAL-PDT) response in a rat model of advanced ovarian cancer. Intraperitoneal 10(6) NuTu 19 cells were injected in 26 female rats Fisher 344. Peritoneal carcinomatosis was obtained 26 days post-tumor induction. Four hours post-intraperitoneal HAL (Photocure ASA, Oslo, Norway) injection, a laparoscopic procedure (D-light AutoFluorescence system, Karl Storz endoscope, Tuttlingen, Germany) and a fluorescence examination were made for 22 rats. The first group (LASER group, n=26) was illuminated with laser light using a 532 nm KTP laser (Laser Quantum, Stockport, UK) on 1 cm(2) surface at 45 J/cm(2). The second group (NO LASER group, n=26) served as controls. Biopsies were taken 24 hours after PDT. Semi-quantitative histology was performed and necrosis value was determined: 0--no necrosis to 4--full necrosis. Fluorescence was monitored before and after illumination on complete responders (NV=3-4; n=20) and non-responders (NV=0-2; n=6). High PpIX photobleaching corresponded with complete responders whereas low photobleaching corresponded with non-responders (P<0.05). A direct linear correlation was shown between photobleaching and necrosis (R(2)=0.89). In vivo PpIX fluorescence photobleaching is useful to predict the tissue response to HAL-PDT.

    • "Recent progress in nanopharmaceutical research has proposed a few methods to tackle these problems [8] . Researchers have developed various types of nanoscale drug carriers to deliver photosensitizers, such as liposomes [4,5], polymer carriers [9], polyoxyethylene cremophor emulsions [10], and microspheres and nanoparticles [11]. Although these carriers improve photosensitizer properties , their use necessarily involves processes to release the loaded drugs that decrease the rate at which tumor cells absorb photosensitizers, extending the period of time required to reach effective concentrations [12]. "
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    Full-text · Article · Jun 2014 · Nanoscale Research Letters
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    Full-text · Article · Jun 2014 · ecancermedicalscience
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    • "Indeed, PS photobleaching is a cost-effective implicit dosimetric parameter that has previously been useful in predicting PDT response.[8] A study by Ascencio and colleagues demonstrated that protoporphyrin IX (PpIX) photobleaching correlated strongly with necrotic score after intraperitoneal hexaminolevulinate based PDT in rats.[9] A previous study from our laboratory showed that BPD photobleaching linearly correlated with normalized viability of 3D ovarian cancer (OvCa) nodules treated with fixed concentrations of BPD.[2] Building on the elegant work of others[6] [10] [11], the present study demonstrates that a simple calculation of PDT dose, defined as the product of BPD concentration and delivered fluence, does not predict PDT outcome in 3D OvCa nodules treated with different concentrations of BPD. "
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    Full-text · Article · Mar 2013 · Proceedings of SPIE - The International Society for Optical Engineering
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