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Mendes RJS, de Sousa NM, Furtado GS, Paschoal MAB, Lago ADN. Association of Papacarie Duo® and low-level laser in antimicrobial photodynamic therapy (aPDT). Lasers Med Sci 2024; 39:25. [PMID: 38198068 DOI: 10.1007/s10103-024-03981-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 01/04/2024] [Indexed: 01/11/2024]
Abstract
Dental caries is a multifactorial, non-communicable disease. Effective treatment options for minimally invasive removal of carious tissue include Papacarie Duo® gel and antimicrobial photodynamic therapy (aPDT). aPDT involves a combination of a light source and photosensitizer. Given that Papacarie Duo® contains a percentage of blue dye, this study aims to explore the antimicrobial potential of Papacarie Duo® when associated with a light source against Streptococcus mutans strains. The chosen light source was a low-power diode laser (λ = 660 nm, E = 3 J, P = 100 mW, t = 30 s). To assess antimicrobial capacity, planktonic suspensions of Streptococcus mutans were plated on Brain Heart Infusion Agar (BHI) to observe the formation of inhibition halos. The studied groups included methylene blue (0.005%), Papacarie Duo®, distilled water (negative control), 2% chlorhexidine (positive control), Papacarie Duo® + laser, and methylene blue (0.005%) + laser. Following distribution onto plates, each group was incubated at 37 °C for 48 h under microaerophilic conditions. Inhibition halos were subsequently measured using a digital caliper. The results showed that chlorhexidine had the greatest antimicrobial effect followed by the group of irradiated methylene blue and irradiated Papacarie Duo®. All experimental groups demonstrated antimicrobial potential, excluding the negative control group. The study concludes that Papacarie Duo® exhibits antimicrobial properties when associated with a low-power diode laser.
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Affiliation(s)
- Roberta Janaina Soares Mendes
- Department of Dentistry I, Federal University of Maranhão (UFMA), Avenida Dos Portugueses, 1966, Vila Bacanga, São Luís, MA, 65080-805, Brazil.
| | - Nayanna Matos de Sousa
- Department of Dentistry I, Federal University of Maranhão (UFMA), Avenida Dos Portugueses, 1966, Vila Bacanga, São Luís, MA, 65080-805, Brazil
| | - Guilherme Silva Furtado
- Department of Dentistry I, Federal University of Maranhão (UFMA), Avenida Dos Portugueses, 1966, Vila Bacanga, São Luís, MA, 65080-805, Brazil
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Bown SG. Photodynamic therapy for photochemists. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20120371. [PMID: 23776302 DOI: 10.1098/rsta.2012.0371] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Photodynamic therapy (PDT) is an evolving technique for localized control of diseased tissue with light after prior administration of a photosensitizing agent and in the presence of oxygen. The biological effect is quite different from surgery, radiotherapy and chemotherapy. With no temperature change during treatment, connective tissues like collagen are largely unaffected, so maintaining the mechanical integrity of hollow organs. PDT is of particular value for pre-cancer and early cancers of the skin (not melanomas) and mouth as the cosmetic and functional results are so good. Another key indication is for small areas of cancer that are unsuitable for or have persisted or recurred after conventional management. It can be applied in areas already exposed to the maximum safe dose of radiotherapy. Outside cancer, in ophthalmology, it is established for age-related macular degeneration, and has considerable potential in arterial disease for preventing restenosis after balloon angioplasty and in the treatment of infectious diseases, where the responsible organisms are accessible to both the photosensitizer and light. New developments on the horizon include techniques for increasing the selectivity for cancers, such as coupling photosensitizers to antibodies, and for stimulating immunological responses, but many further pre-clinical and clinical studies are needed to establish PDT's role in routine clinical practice.
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Affiliation(s)
- Stephen G Bown
- National Medical Laser Centre, University College London, London, UK.
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Bugaj A, Kwitniewski M, Iani V, Juzeniene A, Juzenas P, Ma LW, Moan J. Photodynamic therapy with di-l-arginine protoporphyrinate on WiDr human colon adenocarcinoma xenografts in athymic nude mice. Photodiagnosis Photodyn Ther 2007; 4:237-41. [DOI: 10.1016/j.pdpdt.2007.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 08/23/2007] [Accepted: 08/26/2007] [Indexed: 11/27/2022]
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Hajri A, Wack S, Meyer C, Smith MK, Leberquier C, Kedinger M, Aprahamian M. In Vitro and In Vivo Efficacy of Photofrin® and Pheophorbide a, a Bacteriochlorin, in Photodynamic Therapy of Colonic Cancer Cells¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750140ivaive2.0.co2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Hornung R, Fehr MK, Walt H, Wyss P, Berns MW, Tadir Y. PEG-m-THPC-mediated Photodynamic Effects on Normal Rat Tissues¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0720696pmtmpe2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Woodhams JH, MacRobert AJ, Novelli M, Bown SG. Photodynamic therapy with WST09 (Tookad): quantitative studies in normal colon and transplanted tumours. Int J Cancer 2006; 118:477-82. [PMID: 16052532 DOI: 10.1002/ijc.21335] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Photodynamic therapy (PDT) is attracting increasing interest for the safe destruction of localised tumours in a range of organs. However, most photosensitising drugs require a delay of hours to days between drug administration and light activation with skin photosensitivity that may last for weeks. WST09 (Tookad) is a new faster acting photosensitiser that clears within a few hours. In normal rat colon, after sensitisation with an intravenous bolus of WST09, light was delivered to a single point on the mucosa and the extent of PDT necrosis measured 3 days later. The lesion diameter was greatest with the highest dose of drug and light and the shortest drug light interval (DLI), falling rapidly with a DLI more than 5 min. In tumours transplanted subcutaneously or into the colon, the extent of necrosis only started falling with a DLI greater than 15 min, suggesting a possible window for tumour selectivity. Histological changes 3 days after PDT were essentially the same as those seen with longer acting photosensitisers. The lesion dimensions were comparable to the largest ones seen with other photosensitisers under similar experimental conditions. We conclude that WST09 is a powerful photosensitiser that produces PDT effects similar to those seen with longer acting drugs, but with the major advantages of a short DLI and rapid clearance.
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Affiliation(s)
- Josephine H Woodhams
- National Medical Laser Centre, Academic Division of Surgical Specialities, Royal Free and University College Medical School, University College London, London, United Kingdom
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Wolfsen HC. Uses of photodynamic therapy in premalignant and malignant lesions of the gastrointestinal tract beyond the esophagus. J Clin Gastroenterol 2005; 39:653-64. [PMID: 16082272 DOI: 10.1097/01.mcg.0000173930.60115.62] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Much has recently been written regarding the use of photodynamic therapy for the treatment of esophageal carcinoma and dysplastic Barrett's esophagus. This review, however, describes the clinical experience using photodynamic therapy with various photosensitizer agents for the treatment of diseases in other areas of the gut, especially the pancreaticobiliary tract where European studies have established the role of porfimer sodium photodynamic therapy in the management of patients with cholangiocarcinoma.
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Affiliation(s)
- Herbert C Wolfsen
- Photodynamic Therapy, Esophageal Disease Clinic, Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL 32224, USA.
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Cheung R, Solonenko M, Busch TM, Del Piero F, Putt ME, Hahn SM, Yodh AG. Correlation of in vivo photosensitizer fluorescence and photodynamic-therapy-induced depth of necrosis in a murine tumor model. JOURNAL OF BIOMEDICAL OPTICS 2003; 8:248-52. [PMID: 12683850 DOI: 10.1117/1.1560011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2002] [Revised: 08/27/2002] [Accepted: 11/14/2002] [Indexed: 05/23/2023]
Abstract
We compared light-induced fluorescence (LIF) to nominal injected drug dose for predicting the depth of necrosis response to photodynamic therapy (PDT) in a murine tumor model. Mice were implanted with radiation-induced fibrosarcoma (RIF) and were injected with 0, 5, or 10 mg/kg Photofrin. 630-nm light (30 J/cm(2), 75 mW/cm(2)) was delivered to the tumor after 24 hours. Fluorescence emission (lambda(excitation)=545 nm, lambda( emission)=628 nm) from the tumor was measured. The LIF data had less scatter than injected drug dose, and was found to be at least as good as an injected drug dose for predicting the depth of necrosis after PDT. Our observations provide further evidence that fluorescence spectroscopy can be used to quantify tissue photosensitizer uptake and to predict PDT tissue damage.
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Affiliation(s)
- Rex Cheung
- University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, Pennsylvania 19104, USA
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Barr H, Kendall C, Stone N. Photodynamic therapy for esophageal cancer: a useful and realistic option. Technol Cancer Res Treat 2003; 2:65-76. [PMID: 12625755 DOI: 10.1177/153303460300200108] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The use of light therapy for tissue destruction is highly attractive for the endoscopic and minimally invasive therapy of esophageal cancer. Photodynamic therapy (PDT) offers the possibility of palliation of advanced obstructing tumors. However, there are other competing techniques, which can be used to open the esophageal lumen. It has also proved very effective in providing prolonged palliation of patients with advanced irresectable cancer. Completely obstructing tumors, tortuous and long lesions, and tumors near the upper end of the esophagus are particularly suitable for photodynamic therapy. Patients with obstruction to an esophageal prosthesis are also well palliated with PDT. A more interesting and exciting development is its use for the eradication of early asymptomatic mucosal disease. Photodynamic therapy is particularly useful for the eradication of field cancerous change in patients with pre-malignant Barrett's esophagus, or early tumors in patients unfit for radical therapy.
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Affiliation(s)
- Hugh Barr
- Cranfield Postgraduate Medical School, Gloucestershire Royal Hospital, Great Western Road, Gloucester, GL1 3NN, UK.
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11
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Nagamine N, Ido K, Saihuku K, Higashizawa T, Ono K, Hirasawa T, Sugano K, Chong JM. Photodynamic effects on rabbit auricular veins after photosensitization with porfimer sodium: Implications of the results with respect to the treatment of esophageal varices with photodynamic therapy. Gastrointest Endosc 2002; 55:420-4. [PMID: 11868022 DOI: 10.1067/mge.2002.121599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND There are numerous clinical applications for photodynamic therapy in the GI tract. The principal reason for the wide variety of lesions amenable to photodynamic therapy is the ability to treat large areas of mucosa without the need for complete visualization. This report describes observed hemodynamic and histologic changes in rabbit auricles after photodynamic therapy and the feasibility of photodynamic therapy for esophageal varices. METHODS Porfimer sodium and an argon-dye laser (630 nm, 300 mW/cm(2)) were used. Twenty rabbits were grouped according to porfimer sodium dose: group 1 (2.0 mg/kg, n = 10); group 2 (1.0 mg/kg, n = 6); group 3 (0.2 mg/kg, n = 4). Rabbit auricular veins were classified according to time duration of laser illumination: V(0), no illumination; V(5), 5 minutes; V(10), 10 minutes; V(15), 15 minutes. Hemodynamic changes were observed with a laser Doppler blood flow meter. Histologic changes were evaluated by light microscopy. RESULTS For groups 1 and 2, there was a significant decrease in blood flow for V(15) after photodynamic therapy, but not in group 3. There was a significant difference in the grade of thrombus between V(5) and V(15) in groups 1 and 2, and between V(10) and V(15) in group 2. There was a significant difference in the grade of venous dilation (congestion) for V(15) between groups 1 and 3 (p < 0.05, Kruskal-Wallis test). CONCLUSIONS Endoscopic photodynamic therapy could possibly improve the outcome for endoscopic treatment of esophageal varices beyond that achieved by sclerotherapy or band ligation alone.
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Affiliation(s)
- Nobuhiko Nagamine
- Department of Gastroenterology, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0498, Japan
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Hajri A, Wack S, Meyer C, Smith MK, Leberquier C, Kedinger M, Aprahamian M. In vitro and in vivo efficacy of photofrin and pheophorbide a, a bacteriochlorin, in photodynamic therapy of colonic cancer cells. Photochem Photobiol 2002; 75:140-8. [PMID: 11883602 DOI: 10.1562/0031-8655(2002)075<0140:ivaive>2.0.co;2] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study was designed to investigate the efficacy of photodynamic therapy (PDT) in treating colonic cancer in a preclinical study. Photofrin, a porphyrin mixture, and pheophorbide a (Ph a), a bacteriochlorin, were tested on HT29 human colonic tumor cells in culture and xenografted into athymic mice. Their pharmacokinetics were investigated in vitro, and the PDT efficacy at increasing concentrations was determined with proliferative, cytotoxic and apoptotic assessments. The in vivo distribution and pharmacokinetics of these dyes (30 mg/kg, intraperitoneal) were investigated on HT29 tumor-bearing nude mice. The inhibition of tumor growth after a single 100 J/cm2 PDT session was measured by the changes in tumor volume and by histological analysis of tumor necrosis. PDT inhibited HT29 cell growth in culture. The cell photodamage occurred since the time the concentrations of Ph a and Photofrin reached 5.10(-7) M (or 0.3 microg/mL) and 10 microg/mL, respectively. A photosensitizer dose-dependent DNA fragmentation was observed linked to a cleavage of poly(ADP-ribose) polymerase and associated with an increased expression of mutant-type p53 protein. PDT induced a 3-week delay in tumor growth in vivo. The tumor injury was corroborated by histological observation of necrosis 48 h after treatment, with a correlated loss of specific enzyme expression in most of the tumor cells. In conclusion, PDT has the ability to destroy human colonic tumor cells in vitro and in vivo. This tumoricidal effect is likely associated with a p53-independent apoptosis, as HT29 cells express only mutated p53. The current study suggests a preferential use of Photofrin in PDT of colonic cancer because it should be more effective in vivo than Ph a as a consequence of better tumor uptake.
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Affiliation(s)
- A Hajri
- INSERM Unit 375, IRCAD, Hĵpitaux Universitaires, BP 426, Strasbourg, France
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Pham TH, Hornung R, Berns MW, Tadir Y, Tromberg BJ. Monitoring tumor response during photodynamic therapy using near-infrared photon-migration spectroscopy. Photochem Photobiol 2001. [PMID: 11421074 DOI: 10.1562/0031-8655(2001)0730669mtrdpt2.0.co2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Benzoporphyrin-derivative (BPD)-monoacid-ring A photodynamic therapy (PDT) was performed on subcutaneous tumor implants in a rat ovarian cancer model. In order to assess PDT efficacy the tumor and normal tissue optical properties were measured noninvasively prior to and during PDT using frequency-domain photon migration (FDPM). FDPM data were used to quantify tissue absorption and reduced scattering properties (given by the parameters mu a and mu's, respectively) at four near-infrared (NIR) wavelengths (674, 811, 849 and 956 nm). Tissue physiologic properties, including the in vivo concentration of BPD, deoxy-hemoglobin (Hb), oxy-hemoglobin (HbO2), total hemoglobin (TotHb), water (H2O) and percent tissue hemoglobin oxygen saturation (%StO2), were calculated from optical property data. PDT efficacy was also determined from morphometric analysis of tumor necrosis in histologic specimens. All the measured tumor properties changed significantly during PDT. [Hb] increased by 9%, while [HbO2], [TotHb] and %StO2 decreased by 18, 7 and 12%, respectively. Using histologic data we show that long-term PDT efficacy is highly correlated to mean BPD concentration in tumor and PDT-induced acute changes in [HbO2], [TotHb] and %StO2 (correlation coefficients of 0.829, 0.817 and 0.953, respectively). Overall, our results indicate that NIR FDPM spectroscopy is able to quantify noninvasively and dynamically the PDT-induced physiological effects in vivo that are highly correlated with therapeutic efficacy.
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Affiliation(s)
- T H Pham
- Laser Microbeam and Medical Program (LAMMP), Beckman Laser Institute and Medical Clinic, University of California, 1002 Health Sciences Road East, Irvine, CA 92612, USA
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Pham TH, Hornung R, Berns MW, Tadir Y, Tromberg BJ. Monitoring tumor response during photodynamic therapy using near-infrared photon-migration spectroscopy. Photochem Photobiol 2001; 73:669-77. [PMID: 11421074 DOI: 10.1562/0031-8655(2001)073<0669:mtrdpt>2.0.co;2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Benzoporphyrin-derivative (BPD)-monoacid-ring A photodynamic therapy (PDT) was performed on subcutaneous tumor implants in a rat ovarian cancer model. In order to assess PDT efficacy the tumor and normal tissue optical properties were measured noninvasively prior to and during PDT using frequency-domain photon migration (FDPM). FDPM data were used to quantify tissue absorption and reduced scattering properties (given by the parameters mu a and mu's, respectively) at four near-infrared (NIR) wavelengths (674, 811, 849 and 956 nm). Tissue physiologic properties, including the in vivo concentration of BPD, deoxy-hemoglobin (Hb), oxy-hemoglobin (HbO2), total hemoglobin (TotHb), water (H2O) and percent tissue hemoglobin oxygen saturation (%StO2), were calculated from optical property data. PDT efficacy was also determined from morphometric analysis of tumor necrosis in histologic specimens. All the measured tumor properties changed significantly during PDT. [Hb] increased by 9%, while [HbO2], [TotHb] and %StO2 decreased by 18, 7 and 12%, respectively. Using histologic data we show that long-term PDT efficacy is highly correlated to mean BPD concentration in tumor and PDT-induced acute changes in [HbO2], [TotHb] and %StO2 (correlation coefficients of 0.829, 0.817 and 0.953, respectively). Overall, our results indicate that NIR FDPM spectroscopy is able to quantify noninvasively and dynamically the PDT-induced physiological effects in vivo that are highly correlated with therapeutic efficacy.
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Affiliation(s)
- T H Pham
- Laser Microbeam and Medical Program (LAMMP), Beckman Laser Institute and Medical Clinic, University of California, 1002 Health Sciences Road East, Irvine, CA 92612, USA
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Barr H, Dix AJ, Kendall C, Stone N. Review article: the potential role for photodynamic therapy in the management of upper gastrointestinal disease. Aliment Pharmacol Ther 2001; 15:311-21. [PMID: 11207506 DOI: 10.1046/j.1365-2036.2001.00936.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
Photodynamic therapy involves the activation of an exogenously administered, or an endogenously generated, photosensitizer with light to produce localized tissue destruction. It is an attractive, predominantly endoscopic technique for the palliation of advanced upper gastrointestinal cancer and the eradication of early neoplastic and pre-neoplastic lesions. The nature of the biological response allowing safe healing and the exploitation of tissue threshold effects mean that adjacent tissue damage can be minimized. This review used a database of 368 papers. The nature of the photosensitizer is critical to the depth of tissue damage and the risk of adjacent tissue damage and stricture formation. The generation of protoporphyrin IX following administration of 5-aminolaevulinic acid has proved useful for the treatment of high-grade dysplasia in Barrett's oesophagus. A double-blind randomized placebo controlled trial has confirmed that it is a safe and effective method for the ablation of low-grade dysplasia. The treatment of more advanced lesions requires exogenously administered photo-sensitizers. However, recent data indicate that the neoplastic potential remains in some patients and continued follow-up is necessary. Photodynamic therapy can be used to eradicate early neoplasia and palliate advanced cancer, but caution is required before a definitive cure can be claimed.
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Affiliation(s)
- H Barr
- Cranfield Postgraduate Medical School in Gloucestershire, Gloucestershire Royal Hospital, Gloucester, UK.
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Hornung R, Fehr MK, Walt H, Wyss P, Berns MW, Tadir Y. PEG-m-THPC-mediated photodynamic effects on normal rat tissues. Photochem Photobiol 2000; 72:696-700. [PMID: 11107857 DOI: 10.1562/0031-8655(2000)072<0696:pmtmpe>2.0.co;2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Photodynamic therapy (PDT) of malignancies uses light to activate a photosensitizer preferentially accumulated in cancer cells. The first pegylated photosensitizer, tetrakis-(m-methoxypolyethylene glycol) derivative of 7,8-dihydro-5,10,15,20-tetrakis(3-hydroxyphenyl)-21-23-[H]-porphyrin (PEG-m-THPC), was evaluated in non-tumor-bearing rats. The aim of this study was to assess the photodynamic threshold for damage and its sequelae in normal rat tissue. Thirty-five Fischer rats were sensitized with 3, 9 or 30 mg/kg body weight PEG-m-THPC. Colon, vagina and perineum were irradiated with laser light of 652 nm wavelength and an optical dose of 50, 150 or 450 J/cm fiber length. Temperature in the pelvis was measured during PDT. Three days following PDT the effect on skin, vagina, colon, striated muscle, connective tissue, nerves and blood vessels was assessed by histology. The healing of the above-mentioned tissues was assessed on two rats 3 and 8 weeks after PDT using 9 mg/kg PEG-m-THPC activated with 450 J/cm laser light. No dark toxicity was observed. PDT using 30 mg/kg PEG-m-THPC induced severe necrosis irrespective of the optical dose. Body weight of 9 or 3 mg/kg activated with less than 450 J/cm induced moderate or no damage. No substantial increase in body temperature was seen during PDT. Tissues with severe PDT-induced damage seem to have a good tendency to regenerate. We conclude that within the dose required for tumor treatment PEG-m-THPC is a safe photosensitizer with promising properties. PDT of the colon mucosa below 9 mg/kg PEG-m-THPC and 150 J/cm seems to be safe. All other tissues can be exposed to 9 mg/kg PEG-m-THPC activated with less than 450 J/cm laser light with little side effects.
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Affiliation(s)
- R Hornung
- Beckman Laser Institute and Medical Clinic, University of California, Irvine, USA.
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Abstract
Photodynamic therapy is now a useful and practical option of the local treatment of gastrointestinal cancers. There is increasing screening and surveillance of patients at risk of oesophageal and gastric cancers. The early detection of disease is often unhelpful if an elderly or frail patient needs to be subjected to radical resectional surgery. Photodynamic therapy can eradicate and cure early mucosal disease following a single endoscopic treatment. If the disease is more advanced good local control and palliation is often possible. Overall, palliation can often be achieved using simpler methods which are highly effective and not associated with the problems of prolonged photosensitisation. It is rapidly becoming clear that the ideal indication is for the treatment of dysplastic lesions in the oesophagus associated with columnar-lined oesophagus (Barrett's oesophagus). In these circumstances a heterogeneous field change often with multifocal dysplasia or cancer can be widely eradicated. Similar areas of squamous dysplasia in the upper oesophagus can be treated. At present a major complication of stricture formation is associated with the use of some photosensitisers. The treatment of cancer at the ampulla of Vater and choriocarcinoma is also proving very effective. The treatment can be performed at endoscopy and is well tolerated and safe.
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Affiliation(s)
- H Barr
- Gloucestershire Royal and Cranfield University Institute of Medical Sciences, Gloucestershire Royal Hospital, Gloucester, England.
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Hornung R, Fehr MK, Monti-Frayne J, Krasieva TB, Tromberg BJ, Berns MW, Tadir Y. Highly Selective Targeting of Ovarian Cancer with the Photosensitizer PEG-m-THPC in a Rat Model. Photochem Photobiol 1999. [DOI: 10.1111/j.1751-1097.1999.tb08261.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hornung R, Fehr MK, Monti-Frayne J, Tromberg BJ, Berns MW, Tadir Y. Minimally-invasive debulking of ovarian cancer in the rat pelvis by means of photodynamic therapy using the pegylated photosensitizer PEG-m-THPC. Br J Cancer 1999; 81:631-7. [PMID: 10574248 PMCID: PMC2362885 DOI: 10.1038/sj.bjc.6690740] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Interstitial photodynamic therapy (PDT) using the pegylated photosensitizer PEG-m-THPC was evaluated as a minimally-invasive procedure to selectively debulk unrespectable pelvic ovarian cancer (NuTu-19) in immunocompetent rats. To assess tumour selectivity, PEG-m-THPC at dosages of 0.3, 3.0 and 30 mg kg(-1) body weight was administered intravenously to 30 rats 4 weeks following tumour induction. Eight days later laser light at 652 nm and optical doses ranging from 100 to 900 J cm(-1) diffuser-length was delivered by an interstitial cylindrical diffusing fibre inserted blindly into the pelvis. Three days following light application, the volume of necrosis was measured and the damage to pelvic organs was assessed histologically on cross sections. For analysis of survival, 20 tumour-bearing rats received PDT using drug doses of 3 or 9 mg kg(-1) body weight and an optical dose of 900 J cm(-1) diffuser-length, whereas ten untreated tumour-bearing rats served as controls. The histological assessment of PDT induced necrosis showed a non-linear dose-response for both the photosensitizer dose and the optical dose. The lowest drug dose activated with the highest optical dose did not induce more necrosis than seen in tumour-bearing control animals. The same optical dose induced necrosis of 17 mm in diameter using 30 mg kg(-1) and 11 mm using 3 mg kg(-1) photosensitizer. The optical threshold for induction of significant necrosis was between 100 and 300 J cm(-1) diffuser-length for 30 mg kg(-1) and between 300 and 500 J cm(-1) for 3 mg kg(-1) PEG-m-THPC. Significant damage to normal pelvic organs was only seen if 30 mg kg(-1) photosensitizer was activated with optical doses of 700 J cm(-1) or more. In the survival study, all treated animals survived PDT for at least 2 weeks and the intestinal and urinary tract remained functional. No clinical signs of blood vessel or nerve injury were observed. Mean overall survival of untreated tumour-bearing rats was 25.0 +/- 4.5 days compared to 38.4 +/- 3.8 days and 40.0 +/- 3.6 days for rats treated with 3 mg kg(-1) or 9 mg kg(-1) PEG-m-THPC mediated PDT respectively (P < 0.05). We conclude that PEG-m-THPC mediated PDT has a favourable therapeutic window and that this minimally-invasive procedure can reduce pelvic cancer bulks effectively and selectively.
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Affiliation(s)
- R Hornung
- Beckman Laser Institute and Medical Clinic, University of California Irvine, 92612, USA
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Fielding DI, Buonaccorsi GA, MacRobert AJ, Hanby AM, Hetzel MR, Bown SG. Fine-needle interstitial photodynamic therapy of the lung parenchyma: photosensitizer distribution and morphologic effects of treatment. Chest 1999; 115:502-10. [PMID: 10027453 DOI: 10.1378/chest.115.2.502] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVE To look at the effect of interstitial photodynamic therapy (PDT) in normal lung parenchyma to assess its potential for treating localized, peripheral lung tumors. DESIGN Studies were performed on normal Wistar rats using the photosensitizer meso-tetrahydroxyphenyl chlorine. Drug distribution was measured by fluorescence microscopy on tissue sections. Light was delivered to the lungs via a single fiber inserted percutaneously under x-ray control and the PDT effect studied in animals killed at times up to 6 months later. RESULTS Fluorescence studies showed that the drug was initially distributed throughout the lung, but was later predominantly in the vasculature, bronchi, and macrophages. PDT produced sharply defined zones of hemorrhagic necrosis up to 12 mm in diameter that healed with regeneration of bronchial epithelium and local fibrosis. Different histologic effects were seen between drug light intervals of 1 and 3 days. Treatment was well tolerated, there was a low incidence of pneumothorax, and as long as the fiber tip was within the lung parenchyma, there was no damage to adjacent tissues. CONCLUSION Interstitial PDT produces zones of necrosis in normal lung that heal safely by a percutaneous technique without affecting adjacent areas of untreated lung. If the lesion size can be increased by using multiple fibers, this could be a promising new technique for treating localized, peripheral lung cancers in patients who are unfit for surgery.
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Affiliation(s)
- D I Fielding
- National Medical Laser Centre, Department of Surgery, University College London Medical School, UK
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21
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Hu M, Brasseur N, Yildiz SZ, van Lier JE, Leznoff CC. Hydroxyphthalocyanines as potential photodynamic agents for cancer therapy. J Med Chem 1998; 41:1789-802. [PMID: 9599230 DOI: 10.1021/jm970336s] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A series of benzyl-substituted phthalonitriles, substituted at the 3-, 4-, and 4,5-positions, underwent varied condensations with phthalonitrile to give a series of protected (monohydroxy- and polyhydroxyphthalocyaninato)zinc(II) derivatives which were readily cleaved to give several hydroxyphthalocyanines (ZnPc) (phthalocyanine phenol analogues). Their efficacy as sensitizers for the photodynamic therapy (PDT) of cancer was evaluated on the EMT-6 mammary tumor cell line. In vitro, the 2-hydroxy ZnPc (32) was the most active, followed by the 2,3- and 2,9-dihydroxy ZnPc (39 and 45), with the 2,9,16-trihydroxy ZnPc (33) exhibiting the least activity. In vivo, the monohydroxy derivative 32 and the 2,3-dihydroxy derivative 39 were both efficient in inducing tumor necrosis at 1 micromol kg-1, but complete tumor regression was poor, even at 2 micromol/kg. In contrast, the 2,9-dihydroxy isomer 45, at 2 micromol kg-1, induced tumor necrosis in all animals treated, with 75% complete regression. These results underline the importance of the position of the substituents on the Pc macrocycle to optimize tumor response and confirm the PDT potential of the unsymmetrical Pcs bearing functional groups on adjacent benzene rings.
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Affiliation(s)
- M Hu
- Department of Chemistry, York University, Toronto, Ontario M3J 1P3, Canada
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22
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Ketabchi A, MacRobert A, Speight PM, Bennett JH. Induction of apoptotic cell death by photodynamic therapy in human keratinocytes. Arch Oral Biol 1998; 43:143-9. [PMID: 9602293 DOI: 10.1016/s0003-9969(97)00079-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The use of photodynamic therapy (PDT) for the treatment of skin and oral cancer has been the subject of several clinical studies but there has been little scientific evaluation of its mechanism of action. Evidence to date suggests that whilst epithelial cell death may be secondary to vascular damage, direct cell killing may occur and may involve an apoptosis-like mechanism. To investigate the mechanism of epithelial cell death following PDT, two cell lines, human epidermal keratinocytes (UP) and oral squamous cell carcinoma-derived cells (H376) were subjected to PDT with aluminium disulphonated phthalocyanine (AlS2Pc) as the photosensitizer and red laser light at 675 nm. Control groups received red laser light, photosensitizer or neither. The effects of PDT were assessed using an MTS cell-proliferation assay, which showed a significant reduction in viability (p < 0.01) for PDT-treated cells compared to controls. For morphological analysis, cells were stained with haemotoxylin and eosin and the numbers showing typical apoptotic features counted. The treated cultures showed significantly increased numbers of apoptotic cells. Moreover, the H376 control cultures showed a baseline level of apoptosis of approx. 15%. Apoptosis was confirmed by ultrastructural analysis and by in situ end-labeling of DNA fragments. The results show that PDT using AlS2Pc as a photosensitizer promotes apoptotic cell death in UP and H376 cells in vitro and suggest that direct killing of epithelial cells may contribute to tumour necrosis in vivo.
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Affiliation(s)
- A Ketabchi
- Department of Oral Pathology, Eastman Dental Institute, London
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23
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Kleemann D, MacRobert AJ, Mentzel T, Speight PM, Bown SG. Photodynamic therapy on the normal rabbit larynx with phthalocyanine and 5-aminolaevulinic acid induced protoporphyrin IX photosensitisation. Br J Cancer 1996; 74:49-58. [PMID: 8679457 PMCID: PMC2074606 DOI: 10.1038/bjc.1996.314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Photodynamic therapy (PDT) is a promising technique for the treatment of small tumours in organs where it is essential to minimise damage to immediately adjacent normal tissue as PDT damage to many tissues heals by regeneration rather than scarring. As preservation of function is one of the main aims of treating laryngeal tumours, this project studied the effects of PDT on the normal rabbit larynx with two photosensitisers, endogenous protoporphyrin IX (PPIX) induced by the administration of 5-aminolaevulinic acid (ALA) and disulphonated aluminium phthalocyanine (AIS2Pc). The main aims of the study were to examine the distribution of protoporphyrin IX and AIS2Pc by fluorescence microscopy in the different regions of the larnyx and to assess the nature and subsequent healing of PDT damage. Peak levels of PPIX were found 0.5-4 h after administration of ALA (depending on dose) with highest levels in the epithelium of the mucosa. With 100 mg kg-1, PDT necrosis was limited to the mucosa, whereas with 200 mg kg-1 necrosis extended to the muscle. With 1 mg kg-1 AIS2Pc, 1 h after administration, the drug was mainly in the submucosa and muscle, whereas after 24 h, it was predominantly in the mucosa. PDT at 1 h caused deep necrosis whereas at 24 h it was limited to the mucosa. All mucosal necrosis healed by regeneration whereas deeper effects left some fibrosis. No damage to cartilage was seen in any of the animals studied. The results of this study have shown that both photosensitisers are suitable for treating mucosal lesions of the larynx, but that for both it is important to optimise the drug dose and time interval between drug and light to avoid unacceptable changes in normal areas.
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Affiliation(s)
- D Kleemann
- National Medical Laser Centre, University College London Medical School
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24
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Mlkvy P, Messmann H, Pauer M, Stewart JC, Millson CE, MacRobert AJ, Bown SG. Distribution and photodynamic effects of meso-tetrahydroxyphenylchlorin (mTHPC) in the pancreas and adjacent tissues in the Syrian golden hamster. Br J Cancer 1996; 73:1473-9. [PMID: 8664115 PMCID: PMC2074542 DOI: 10.1038/bjc.1996.279] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Photodynamic therapy (PDT) has the potential to destroy small tumours with safe healing of adjacent normal tissue. This study looks at the effects of PDT on the normal pancreas and adjacent tissues in hamsters using the photosensitiser meso-tetrahydroxyphenylchlorin (mTHPC). Pharmacokinetic studies used fluorescence microscopy on sections of pancreas, stomach and duodenum 1 h to 6 days after mTHPC. Highest levels of sensitiser were seen in the gastric and duodenal mucosa and in the acinar pancreas after 2-4 days. For PDT, light at 652 nm was delivered by placing a 0.2 mm diameter bare-ended fibre against the tissue. An energy of 50 J was used 2 or 4 days after 0.1 or 0.3 mg kg-1 mTHPC and animals killed 1 to 7 days later. Maximum necrosis was seen 3 days after PDT with lesions up to 4 mm in pancreas, 4.5 mm in duodenum and 2.5 mm in stomach. By fractionating the light dose, the lesion size could be increased by 30%. The main complication was free or sealed duodenal perforation (avoided by shielding the duodenum). Partial, reversible bile duct obstruction was seen occasionally. There was no macroscopic damage to the bile ducts or major blood vessels. Apart from the duodenum, all lesions healed safely. In this animal model, only the duodenum was at risk of serious, irreversible damage. Treatment is likely to be safer in the much thicker human duodenum. mTHPC is a powerful photosensitiser and suitable for further study for tumours in the region of the pancreas although care is required near the duodenum.
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Affiliation(s)
- P Mlkvy
- National Cancer Centre, Bratislava, Slovakia
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25
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Messmann H, Mlkvy P, Buonaccorsi G, Davies CL, MacRobert AJ, Bown SG. Enhancement of photodynamic therapy with 5-aminolaevulinic acid-induced porphyrin photosensitisation in normal rat colon by threshold and light fractionation studies. Br J Cancer 1995; 72:589-94. [PMID: 7669566 PMCID: PMC2033889 DOI: 10.1038/bjc.1995.378] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
5-Aminolaevulinic acid (ALA)-induced prophyrin photosensitisation is an attractive option for photodynamic therapy (PDT) since skin photosensitivity is limited to 1-2 days. However, early clinical results on colon tumours using the maximum tolerated oral dose of 60 mg kg-1 showed only superficial necrosis, presumably owing to insufficient intratumoral porphyrin levels, although inadequate light dosimetry may also be a factor. We undertook experiments using ALA, 25-400 mg kg-1 intravenously, to establish the threshold doses required for a PDT effect. Laser light at 630 nm (100 mW, 10-200 J) was delivered to a single site in the colon of photosensitised normal Wistar rats at laparotomy. The animals were killed 3 days later and the area of PDT-induced necrosis measured. No lesion was seen with 25 mg kg-1. The lesion size increased with larger ALA doses and with the light dose but little benefit was seen from increasing the ALA dose above 200 mg kg-1 or the light dose above 100 J. Thus there is a fairly narrow window for optimum doses of drug and light. Further experiments showed that the PDT effect can be markedly enhanced by fractionating the light dose. A series of animals was sensitized with 200 mg kg-1 ALA and then treated with 25 J. With continuous irradiation, the lesion area was 13 mm2, but with a single interruption of 150 s the area rose to 94 mm2 with the same total energy. Results were basically similar for different intervals between fractions (10-900 s) and different numbers of fractions (2-25). This suggests that a single short interruption in the light irradiation may dramatically reduce the net light dose required to achieve extensive necrosis.
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Affiliation(s)
- H Messmann
- Department of Internal Medicine, University of Regensburg, Germany
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26
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Morgan J, Lottman H, Abbou CC, Chopin DK. A comparison of direct and liposomal antibody conjugates of sulfonated aluminum phthalocyanines for selective photoimmunotherapy of human bladder carcinoma. Photochem Photobiol 1994; 60:486-96. [PMID: 7800720 DOI: 10.1111/j.1751-1097.1994.tb05139.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
There is a need to improve the selectivity of photodynamic therapy and for better targeting of tumor cells within specific tumor compartments. Selective in vitro phototoxicity of a human bladder carcinoma cell line 647V has been achieved by targeting sulfonated aluminum phthalocyanines (AlSPc) with monoclonal antibodies. Aluminum tetra-3 sulfonyl chloride phthalocyanine (PC) or rhodamine sulfonyl chloride were directly coupled to antibodies by a sulfonamide linkage and AlSPc or carboxyfluorescein were encapsulated in liposomes of the small unilamellar vesicle type (SUV) bearing antibody. Antibody E7 (IgM subclass), which recognized an antigenic determinant expressed on 647V but was absent on T24 a control human bladder carcinoma cell line, and a control IgM antibody were used. The effects of the two types of conjugate were compared. Immunofluorescence studies on living cells demonstrated specific cell surface localization of conjugates at 4 degrees C and internalization at 37 degrees C. Phototoxicity was measured by 3-(4,5-dimethylthiazol-2-5-diphenyltetrazolium) bromide assay after exposing AlSPc-sensitized cells to red light. Significant AlSPc dose-dependent phototoxicity of the order 4 degrees C < 4 degrees C plus 37 degrees C < 37 degrees C was observed with E7-SUV and E7-PC in the range 1-8 microM AlSPc. At equimolar AlSPc doses absolute toxicity was similar for the two conjugate types, but at equimolar antibody doses, the liposomal conjugate was more effective by up to 13-fold. Addition of urine during illumination decreased toxicity, which was attributed to the presence of protective elements. The results suggest that photosensitizers such as AlSPc could be used for antibody-directed therapy and in particular for selectively damaging tumor cells of the epithelial cell compartment in bladder carcinoma by intrabladder administration. The therapeutic ratio, which takes into account both specific and nonspecific toxicity, was greater for the liposome conjugate than for the direct conjugate indicating their greater suitability for in vivo instillation.
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Affiliation(s)
- J Morgan
- Centre de Recherches Chirurgicales, Creteil, France
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27
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Flynn G, McHale L, McHale AP. Methotrexate-loaded, photosensitized erythrocytes: a photo-activatable carrier/delivery system for use in cancer therapy. Cancer Lett 1994; 82:225-9. [PMID: 8050095 DOI: 10.1016/0304-3835(94)90016-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
With a view towards the design of a system incorporating both the use of chemotherapeutics and photodynamic therapy for use in cancer treatment modalities, erythrocytes have been loaded with methotrexate and subsequently photosensitized by exposure to hematoporphyrin derivative. Loading of methotrexate into erythrocytes has been optimized by examining variations in electroporation conditions. Maximum loading indices observed were in the region of 64%. In order to obtain rapid pre-defined release of chemotherapeutic from the system, the erythrocytes were photosensitized. Light-dependent release of methotrexate from the system was examined. In addition, studies measuring the cytotoxic effects of light-activated release from the system using Hela cells as a target, suggested that decreases in cell viability following exposure to light resulted from the combined effects of chemotherapy and photoradiation therapy. Potential applications and advantages associated with this novel system are discussed.
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Affiliation(s)
- G Flynn
- Department of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, UK
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28
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Mank A, Gooijer C, Lingeman H, Velthorst N, Brinkman U. Selective and sensitive in vitro detection method for aluminum phthalocyanine photosensitizers, using liquid chromatography and diode-laser induced fluorescence. Anal Chim Acta 1994. [DOI: 10.1016/0003-2670(94)80045-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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29
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Ambroz M, MacRobert AJ, Morgan J, Rumbles G, Foley MS, Phillips D. Time-resolved fluorescence spectroscopy and intracellular imaging of disulphonated aluminium phthalocyanine. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1994; 22:105-17. [PMID: 8176544 DOI: 10.1016/1011-1344(93)06955-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Spectroscopic studies were carried out on the photosensitizer disulphonated aluminium phthalocyanine (AlS2Pc) which has prospective applications in photodynamic therapy. The fluorescence lifetimes of AlS2Pc were measured in a range of model systems and cultured leukaemic cells using laser excitation and time-correlated, single-photon-counting detection. In an investigation of non-covalent protein binding, we studied AlS2Pc in the presence of human serum albumin (HSA) in 0.1 M phosphate-buffered saline at pH 7.4. On addition of excess concentrations of HSA, small red shifts in the fluorescence and absorbance spectra were observed, together with an increase in fluorescence polarization anisotropy, consistent with binding of the phthalocyanine. Fluorescence decays could be resolved into two lifetimes for bound AlS2Pc with a dominant component of 5.5 ns and a minor component of 1 ns. Fluorescence imaging and time-resolved microfluorometry were carried out on intracellular AlS2Pc using leukaemic K562 cells. Microscopic imaging with a charge-coupled device (CCD) camera revealed that AlS2Pc fluorescence predominated in a discrete perinuclear region which was then probed selectively by a focused laser spot for fluorescence lifetime measurements. Bi-exponential decays with lifetime components of 6.1 and 2.2 ns were observed. On irradiation at 633 nm, the fluorescence intensity increased initially and subsequently declined due to photodegradation.
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Affiliation(s)
- M Ambroz
- Department of Chemical Physics, Charles University, Prague, Czech Republic
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30
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Mellert U, Beck OJ, Gonnert M, Ruhland B, Unsöld E. Photodynamische Tumor - Fluoreszenzdiagnose und -Therapie mit Disulfoniertem Aluminium - Phthalocyanin am Kaninchengehirn. BIOMED ENG-BIOMED TE 1994. [DOI: 10.1515/bmte.1994.39.s1.231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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31
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Berenbaum MC, Bonnett R, Chevretton EB, Akande-Adebakin SL, Ruston M. Selectivity ofmeso-tetra(hydroxyphenyl)porphyrins and chlorins and of photofrin II in causing photodamage in tumour, skin, muscle and bladder. The comcept of cost-benefit in analysing the results. Lasers Med Sci 1993. [DOI: 10.1007/bf02547845] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Spikes JD, Bommer JC. Photobleaching of mono-L-aspartyl chlorin e6 (NPe6): a candidate sensitizer for the photodynamic therapy of tumors. Photochem Photobiol 1993; 58:346-50. [PMID: 8234467 DOI: 10.1111/j.1751-1097.1993.tb09572.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Most sensitizers used for the photodynamic therapy (PDT) of tumors photobleach on illumination. Thus, it is of interest to examine the photobleaching behavior of new sensitizers proposed for use in PDT. This report surveys the quantum yields and kinetics of the photobleaching of mono-L-aspartyl chlorin e6(NPe6), a hydrophilic chlorin that has many of the photoproperties desirable in a sensitizer for clinical PDT. It is a very effective sensitizer for the PDT of several types of model tumors in animals and is now in Phase I clinical trials. The quantum yield of NPe6 photobleaching in pH 7.4 phosphate buffer in air was 8.2 x 10(-4); this is greater than the yields for typical porphyrin photosensitizers. For example, the yields for hematoporphyrin and uroporphyrin are 4.7 x 10(-5) and 2.8 x 10(-5), respectively. The yield decreased significantly in organic solvents of low dielectric constant. The Sn derivative of NPe6 was more light stable than NPe6 (yield = 5.7 x 10(-6), while the Zn derivative was more sensitive (yield = 1.9 x 10(-2). Oxygen appeared to be necessary for the photobleaching of NPe6; however, bleaching was not inhibited by 100 mM azide, an efficient quencher of singlet oxygen. The photooxidizable substrates cysteine, dithiothreitol and furfuryl alcohol increased the quantum yield of photobleaching two- to four-fold, while the electron acceptor, metronidazole, increased it almost six-fold. Photobleaching yields for several other chlorins were also measured.
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Affiliation(s)
- J D Spikes
- Department of Biology, University of Utah, Salt Lake City 84112
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33
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Smith SG, Bedwell J, MacRobert AJ, Griffiths MH, Bown SG, Hetzel MR. Experimental studies to assess the potential of photodynamic therapy for the treatment of bronchial carcinomas. Thorax 1993; 48:474-80. [PMID: 8322231 PMCID: PMC464496 DOI: 10.1136/thx.48.5.474] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Photodynamic therapy (PDT) is a technique for producing localised tissue necrosis with light after prior administration of a photosensitising drug. There is some selectivity of uptake of photosensitisers in malignant tissue, although this is difficult to exploit. Full thickness necrosis in normal and neoplastic colon heals without perforation because of a lack of effect on collagen, making local cure a possibility. The experiments described here aim to establish whether these conclusions are also valid for bronchial tumours. METHODS In pharmacokinetic studies normal rats were given 5 mg/kg of the photosensitiser aluminium sulphonated phthalocyanine (A1SPc) intravenously and killed up to one month later. The distribution of A1SPc in the trachea was measured by chemical extraction and fluorescence microscopy. In subsequent experiments sensitised animals were treated with light delivered to the tracheal mucosa through a thin flexible fibre and the resultant lesions were studied for their size, mechanical strength, and healing. A series of resected human bronchial carcinomas were examined histologically for their collagen content. RESULTS The tracheal concentration of A1SPc in normal rats was maximum 1-20 hours after administration. Fluorescence microscopy revealed that most was in the perichondrium and submucosal stroma, with little in the cartilage. Light exposure showed necrosis of the soft tissues which healed by regeneration, but no effect on cartilage and no reduction in the mechanical strength of the trachea at any stage. Histological examination of resected human bronchial carcinomas showed more collagen in the tumour areas than would be found in normal regions. CONCLUSIONS PDT leads to necrosis of the soft tissues of the normal trachea but there is complete healing by regeneration, no risk of perforation (due to collagen preservation), and no effect on cartilage. Human bronchial carcinomas apparently contain more collagen than normal bronchi which may give protection against perforation following necrosis induced by PDT. PDT may have a role in eradicating small volumes of tumour tissue in situ and could be valuable for treating (1) small carcinomas in patients unfit for resection, (2) tumour remaining after surgical resection, (3) stump recurrences, or (4) to prolong palliation of tumours after debulking with the NdYAG laser.
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Affiliation(s)
- S G Smith
- National Medical Laser Centre, University College London Medical School
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34
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Spikes JD, Krinick NL, Kopec̆ek J. Photoproperties of a mesochlorin e6—N-(2-hydroxypropyl)methacrylamide copolymer conjugate. J Photochem Photobiol A Chem 1993. [DOI: 10.1016/1010-6030(93)85037-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Ris HB, Altermatt HJ, Nachbur B, Stewart JC, Wang Q, Lim CK, Bonnett R, Althaus U. Effect of drug-light interval on photodynamic therapy with meta-tetrahydroxyphenylchlorin in malignant mesothelioma. Int J Cancer 1993; 53:141-6. [PMID: 8416199 DOI: 10.1002/ijc.2910530126] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The influence of the time interval (TI) between drug administration and laser activation on selectivity of meta-tetrahydroxyphenylchlorin(mTHPC)-mediated photodynamic therapy (PDT) for tumour tissue was assessed in BALB/c nude mice bearing human malignant mesothelioma xenografts. Following i.p. administration of 0.3 mg/kg mTHPC, a light dose of 10 J/cm2 and 0.1 W/cm2 was delivered at 650 nm on the tumour and an equal-sized area of the hind leg after 4, 12, 24 and 36 hr and 2, 3, 4, 5 and 6 days to groups of 6 animals (surface irradiance). Then, 72 hr after light delivery, the depth of necrosis was measured in the tumour and in the skin and underlying muscle of the hind leg. Photosensitized necrosis occurred in normal tissue at TI from 4 hr to 3 days and in the tumour at TI from 12 hr to 4 days. The therapeutic ratio of mTHPC-PDT varied significantly with the time interval between drug administration and laser activation and was greatest at an interval of 3 days. mTHPC concentration was measured in 3 control unirradiated animals at all time points in normal tissues and in tumour tissue, and found to be the same in both tissues. Thus the tissue concentration of mTHPC was of limited use as regards the prediction of photosensitizing effects in the tumour model.
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Affiliation(s)
- H B Ris
- Department of Thoracic and Cardiovascular Surgery, University of Bern, Switzerland
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36
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Loh CS, Bedwell J, MacRobert AJ, Krasner N, Phillips D, Bown SG. Photodynamic therapy of the normal rat stomach: a comparative study between di-sulphonated aluminium phthalocyanine and 5-aminolaevulinic acid. Br J Cancer 1992; 66:452-62. [PMID: 1520582 PMCID: PMC1977931 DOI: 10.1038/bjc.1992.295] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Dysplasia in the upper gastrointestinal tract carries a risk of invasive malignant change. Surgical excision of the affected organ is the only treatment available. Photodynamic therapy has been shown to be promising in the treatment of early and superficial tumours and may be useful for the ablation of dysplastic mucosa. Because of the diffuse nature of the disease, such treatment would necessarily involve destruction of large areas of mucosa and it is desirable to confine its effect to the mucosa in order that safe healing can take place. By means of photometric fluorescence microscopy, we have studied the pattern of photosensitisation in the normal rat stomach using di-sulphonated aluminium phthalocyanine (AlS2Pc) and 5-aminolaevulinic acid (ALA) as photosensitisizers. AlS2Pc resulted in a panmural photosensitisation of the gastric wall with the highest level encountered in the submucosa. The mucosa and muscularis propria were sensitised to equal extent. Following light exposure, a full thickness damage resulted. ALA is a natural porphyrin precursor and exogenous administration gave rise to accumulation of protoporphyrin IX (PPIX) in the cells. The resultant pattern of photosensitisation was predominantly mucosal and its photodynamic effect was essentially confined to the mucosa. ALA produced a selective photosensitisation of the gastric mucosa for its photodynamic ablation with sparing the underlying tissue layers.
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Affiliation(s)
- C S Loh
- Gastroenterology Unit, Walton Hospital, Liverpool, UK
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37
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Chatlani PT, Nuutinen PJ, Toda N, Barr H, MacRobert AJ, Bedwell J, Bown SG. Selective necrosis in hamster pancreatic tumours using photodynamic therapy with phthalocyanine photosensitization. Br J Surg 1992; 79:786-90. [PMID: 1393474 DOI: 10.1002/bjs.1800790826] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Photodynamic therapy (PDT) is often thought to be able to effect selective tumour necrosis. This therapeutic selectivity, based on transient differences in tumour: normal tissue photosensitizer concentration ratios, is rarely useful clinically in extracranial tumours, although PDT itself may be of value by virtue of the nature of the damage produced and healing of normal tissue by regeneration. This report describes the effects of PDT on normal pancreas and chemically induced pancreatic cancers in the hamster, where a different mechanism of selective necrosis may be seen. Photosensitizer distribution in normal and neoplastic pancreas was studied by chemical extraction and fluorescence microscopy. Correlation of distribution studies with necrosis produced by PDT shows that the photodynamic dose (product of tissue concentration of sensitizer and light dose) threshold for damage is seven times as high for normal pancreas as for pancreatic cancer. Tumour necrosis extended to the point where tumour was invading normal areas without damaging the normal tissue. In rat colonic cancer, photodynamic dose thresholds in tumour and normal tissue are similar and so such marked selectivity of necrosis is not possible. The reason for this selectivity in the pancreas is not clear, but recent evidence has suggested a difference in response to PDT between normal and neoplastic pancreatic cell lines and the presence of a singlet oxygen scavenger in normal pancreas is postulated. Furthermore, the present fluorescence microscopy studies suggest that tumour stroma contains the highest level of photosensitizer and thus receives the highest photodynamic dose during PDT. These results suggest a possible role for PDT in treating small pancreatic tumours or as an adjuvant to other techniques, such as surgery, that reduce the main bulk of tumours localized to the pancreas.
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Affiliation(s)
- P T Chatlani
- National Medical Laser Centre, University College London, UK
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38
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Boyle RW, Paquette B, van Lier JE. Biological activities of phthalocyanines. XIV. Effect of hydrophobic phthalimidomethyl groups on the in vivo phototoxicity and mechanism of photodynamic action of sulphonated aluminium phthalocyanines. Br J Cancer 1992; 65:813-7. [PMID: 1616852 PMCID: PMC1977750 DOI: 10.1038/bjc.1992.174] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aluminium phthalocyanines substituted to different degrees with hydrophilic sulphonic acid and hydrophobic phthalimidomethyl groups were investigated in vivo as new agents for the photodynamic therapy of malignant tumours. Parameters studied included the photodynamic action on EMT-6 mammary tumours in BALB/c mice, the therapeutic window and the potential for direct cell killing, assayed via an in vivo/in vitro test. Although the efficiency of photoinactivation of the EMT-6 tumour increases by a factor of ten with reduction of the number of sulphonic acid groups from four to two, no further effect was seen with the addition of the hydrophobic phthalimidomethyl groups. Addition of the latter groups however increased the potential for direct cell killing by a factor of two and expanded the therapeutic window by a factor of four, thus improving the usefulness of the dye as a photosensitiser for the photodynamic therapy of cancer.
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Affiliation(s)
- R W Boyle
- MRC Group in the Radiation Sciences, Faculty of Medicine, University of Sherbrooke, Québec, Canada
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39
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Spikes JD. Quantum yields and kinetics of the photobleaching of hematoporphyrin, Photofrin II, tetra(4-sulfonatophenyl)-porphine and uroporphyrin. Photochem Photobiol 1992; 55:797-808. [PMID: 1409888 DOI: 10.1111/j.1751-1097.1992.tb08527.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Porphyrins used as sensitizers for the photodynamic therapy (PDT) of tumors are progressively destroyed (photobleached) during illumination. If the porphyrin bleaches too rapidly, tumor destruction will not be complete. However, with appropriate sensitizer dosages and bleaching rates, irreversible photodynamic injury to the normal tissues surrounding the tumor, which retain less sensitizer, may be significantly decreased. This paper surveys the quantum yields and kinetics of the photobleaching of four porphyrins: hematoporphyrin (HP), Photofrin II (PF II), tetra(4-sulfonatophenyl)porphine (TSPP) and uroporphyrin I (URO). The initial quantum yields of photobleaching, as measured in pH 7.4 phosphate buffer in air, were: 4.7 x 10(-5), 5.4 x 10(-5), 9.8 x 10(-6), and 2.8 x 10(-5) for HP, PF II, TSPP and URO respectively; thus, the rates of photobleaching are rather slow. Low oxygen concentration (2 microM) significantly reduced the photobleaching yields. However, D2O increased the yields only slightly, and the singlet oxygen quencher, azide, had no effect, even at 0.1 M. Photosensitizing porphyrins in body fluids, cells and tissues may be closely associated with various photooxidizable molecules and electron acceptors and donors. Therefore, selected model compounds in these categories were examined for their effects on porphyrin photobleaching. A number inhibited and/or accelerated photobleaching, depending on the compound, the porphyrin and the reaction conditions. For example, 1.0 mM furfuryl alcohol increased the photobleaching yields of HP and URO more than 5-fold, with little effect on PF II or TSPP. In contrast, the electron acceptor, methyl viologen, increased the photobleaching yield of TSPP more than 10-fold, with little accelerating effect on the other porphyrins. These results suggest that the mechanism(s) of the photobleaching of porphyrin photosensitizers in cells and tissues during PDT may be complex.
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Affiliation(s)
- J D Spikes
- Department of Biology, University of Utah, Salt Lake City 84112
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40
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Affiliation(s)
- J Moan
- Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo
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41
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Bedwell J, MacRobert AJ, Phillips D, Bown SG. Fluorescence distribution and photodynamic effect of ALA-induced PP IX in the DMH rat colonic tumour model. Br J Cancer 1992; 65:818-24. [PMID: 1616853 PMCID: PMC1977757 DOI: 10.1038/bjc.1992.175] [Citation(s) in RCA: 217] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aminolaevulinic acid (ALA) is the first committed step in haem synthesis. In the presence of excess ALA the natural regulatory feedback system is disrupted allowing accumulation of protoporphyrin IX (PP IX) the last intermediate product before haem, and an effective sensitiser. This method of endogenous photosensitisation of cells has been exploited for photodynamic therapy (PDT). We have studied the fluorescence distribution and biological effect of induced PP IX in normal and tumour tissue in the rat colon. Fluorescence in normal colonic tissue was at a peak of 4 h with a rapid fall off by 6 h. The fluorescence had returned to background levels by 24 h. All normal tissue layers followed the same fluorescence profile but the mucosa showed fluorescent levels six times higher than the submucosa, with muscle barely above background values. At 6 h the ratio of fluorescence levels between normal mucosa and viable tumour was approximately 1:6. At this time laser treatment showed necrosis of normal mucosa and tumour with sparing of normal muscle. There was good correlation between the fluorescence distribution and the biological effect of ALA-induced photosensitisation on exposure to red light. ALA may be superior to conventional sensitisers for tumours that produce haem as the PP IX is synthesised in malignant cells while the other sensitisers mainly localise to the vascular stroma of tumours. There is also a greater concentration difference between the PP IX levels in tumours and in normal mucosa and normal muscle than with the other photosensitisers raising the possibility of more selective necrosis in tumours.
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Affiliation(s)
- J Bedwell
- Department of Surgery, University College London, UK
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42
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Far-red-absorbing photosensitizers: their use in the photodynamic therapy of tumours. J Photochem Photobiol A Chem 1992. [DOI: 10.1016/1010-6030(92)85065-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Nuutinen PJ, Chatlani PT, Bedwell J, MacRobert AJ, Phillips D, Bown SG. Distribution and photodynamic effect of disulphonated aluminium phthalocyanine in the pancreas and adjacent tissues in the Syrian golden hamster. Br J Cancer 1991; 64:1108-15. [PMID: 1764374 PMCID: PMC1977869 DOI: 10.1038/bjc.1991.473] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Necrosis of small volumes of tumour tissue with photodynamic therapy (PDT) can be achieved relatively easily. For this to be clinically relevant, it is essential to know what the same treatment parameters do to adjacent normal tissues into which the tumour has spread. For pancreatic cancers, local spread to vital structures is common. We have studied chemical extraction, microscopic fluorescence kinetics and photodynamic effects of disulphonated aluminum phthalocyanine (AlS2Pc) in normal pancreas and adjacent tissues in hamsters. Chemical extraction exhibited a peak duodenal concentration of AlS2Pc 48 h after sensitisation, with levels much higher than in stomach and pancreas. With microscopic fluorescence photometry highest levels were seen in duodenal submucosa and bile duct walls 48 h after photosensitisation. Pancreatic ducts, duodenal mucosa and gastric mucosa and submucosa exhibited intermediate fluorescence with relatively weak fluorescence in pancreatic acinar tissue and the muscle layer of the stomach. As expected, on the basis of fluorescence intensity and chemical extraction studies, the duodenal and bile duct wall were the most vulnerable tissues to photodynamic therapy. When the dose of 5 mumol kg-1 of sensitiser was used, duodenal perforations, gastric ulcers and transudation of bile from the bile duct occurred. However, the lesions in the stomach and bile duct healed without perforation or obstruction, so only the duodenum was at risk of serious, irreversible damage. Using a lower dose of photosensitiser markedly reduced damage.
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Affiliation(s)
- P J Nuutinen
- Department of Surgery, Rayne Institute, University College London, UK
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44
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Meyer M, Speight P, Bown SG. A study of the effects of photodynamic therapy on the normal tissues of the rabbit jaw. Br J Cancer 1991; 64:1093-7. [PMID: 1764372 PMCID: PMC1977877 DOI: 10.1038/bjc.1991.470] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Photodynamic therapy (PDT) is an anti-cancer treatment which involves the systemic administration of a photosensitising drug which is preferentially absorbed by tumour tissue. Relatively little drug should be absorbed by the surrounding normal tissues. Tumour destruction is achieved when the tumour is illuminated with light of a wavelength which activates the photosensitising drug thereby inducing a cytotoxic reaction. However studies in many tissues have shown that the hoped for tumour selectivity is rarely achieved. Using the rabbit mandible and gingiva as our models we have studied the effects of various doses of PDT on the tissues of the oral cavity, namely mucosa, bone, muscle and salivary gland. The photosensitiser used was di-sulphonated aluminium phthalocyanine. Results show that whereas bone is extremely resistant to PDT the other tissues are vulnerable to it. In the case of muscle and salivary gland this susceptibility is very much dose related. In salivary tissue necrotising sialometaplasia was observed in areas of the gland adjacent to those that had undergone necrosis. All tissues were noted to heal or regenerate well following PDT injury.
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Affiliation(s)
- M Meyer
- Department of Surgery, University College, University of London, UK
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45
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Gomer CJ. Preclinical examination of first and second generation photosensitizers used in photodynamic therapy. Photochem Photobiol 1991; 54:1093-107. [PMID: 1775531 DOI: 10.1111/j.1751-1097.1991.tb02133.x] [Citation(s) in RCA: 252] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Numerous photosensitizers with absorption peaks spanning the 600-800 nm "therapeutic window" have been and continue to be synthesized. Structural modifications of the dyes can then be made in order to improve tumor deliverability and retention. Chemical alterations can also enhance the yields of light generated reactive oxygen species. Utilization of lipoproteins, emulsions and antibody conjugates can enhance the selectivity of drug localization. Most cell types and subcellular structures are highly photosensitive and biochemical analysis indicates that cellular target sites associated with PDT correlate with photosensitizer location. In vivo data suggest that vascular and direct tumor cell damage as well as systemic and local immunological reactions are involved in PDT responsiveness. Additional mechanistic, synthetic and developmental studies are required in order to fully appreciate the potentials of PDT. However, continued enthusiasm and support for basic PDT research (as observed during the past 8 years) will depend to a large extent on the outcome of the current clinical trials.
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Affiliation(s)
- C J Gomer
- Clayton Ocular Oncology Center, Childrens Hospital of Los Angeles, CA
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46
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Affiliation(s)
- A J Pope
- Institute of Urology, University College and Middlesex School of Medicine, London
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47
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Affiliation(s)
- I Rosenthal
- Department of Food Science, Volcani Center, Bet Dagan, Israel
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48
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Bedwell J, Chatlani PT, MacRobert AJ, Roberts JE, Barr H, Dillon J, Bown SG. Enhanced tumour selectivity of photodynamic therapy in the rat colon using a radioprotective agent. Photochem Photobiol 1991; 53:753-6. [PMID: 1653426 DOI: 10.1111/j.1751-1097.1991.tb09888.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Radioprotective agents have been found to protect normal tissues during photodynamic therapy (PDT). We have investigated a phosphorylated thiol protectant WR-77913 (W7) with the photosensitizer aluminium sulphonated phthalocyanine (AISPc). We compared the effects of PDT on normal and tumour tissue in the rat colon, with and without this protectant. In normal colon no necrosis was seen in sites treated after administration of the W7. Necrosis of mean diameter 4.2 mm was seen in those given the protectant after light exposure. At tumour sites the area of necrosis was similar after light exposure before and after the administration of the protective agent. These results suggest a possible role for W7 in enhancement of selectivity of PDT action. Several mechanisms of protection against porphyrin phototoxicity by these drugs have been proposed, including acceleration of photobleaching. We used fluorescence to detect AISPc in strips of rat colon before and after laser treatment, with and without W7. However, a primary role for the photobleaching of AISPc as the mechanism for the protection shown is not supported by these observations.
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Affiliation(s)
- J Bedwell
- Department of Surgery, University College London, UK
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49
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Chatlani PT, Bedwell J, MacRobert AJ, Barr H, Boulos PB, Krasner N, Phillips D, Bown SG. Comparison of distribution and photodynamic effects of di- and tetra-sulphonated aluminium phthalocyanines in normal rat colon. Photochem Photobiol 1991; 53:745-51. [PMID: 1886934 DOI: 10.1111/j.1751-1097.1991.tb09887.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have previously reported photodynamic therapy of normal rat colon using aluminium sulphonated phthalocyanine (AISPc). In that study, the AISPc used was a mixture of phthalocyanines of different degrees of sulphonation. Phthalocyanines of defined degrees of sulphonation have recently become available and we compared the distribution of the di- and tetra-sulphonates (AIS2Pc and AIS4Pc) in rat colon and colon wall structures employing both chemical extraction and fluorescence photometry using a charge coupled device imaging system. Also, the photodynamic effects produced by these components in rat colon were compared at various times after photosensitization. After intravenous photosensitizer administration using equimolar doses, the concentration of AIS2Pc in colon fell off more rapidly with time than AIS4Pc. Differences were noted in the microscopic distribution of these compounds, with the di-sulphonate exhibiting peak fluorescence in colon wall structures by 1 h after photosensitization, while mucosal fluorescence with the tetra-sulphonate peaked at 5 h. Fluorescence was also lost from the colon wall much more slowly with the tetra-sulphonate, which tended to be retained in the submucosa. Maximum photosensitizing capability was seen at 1 h with AIS2Pc and no lesions could be produced with photodynamic therapy at 1 week, with up to 5.65 mumol/kg. With AIS4Pc (5.65 mumol/kg), while no lesions could be produced with light treatment at 1 h, photodynamic therapy at 1 week produced lesions only slightly smaller than those produced with treatment at 48 h (the time of maximum effect), and significant photosensitization was present at 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P T Chatlani
- Department of Surgery, University College London, Rayne Institute, UK
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50
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Barr H, Chatlani P, Tralau CJ, MacRobert AJ, Boulos PB, Bown SG. Local eradication of rat colon cancer with photodynamic therapy: correlation of distribution of photosensitiser with biological effects in normal and tumour tissue. Gut 1991; 32:517-23. [PMID: 2040475 PMCID: PMC1378929 DOI: 10.1136/gut.32.5.517] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Photodynamic therapy is a photochemical technique for the local destruction of tumours, entailing the interaction of light with an administered photosensitiser to produce a cytotoxic effect. We investigated the tissue distribution of the photosensitiser aluminium sulphonated phthalocyanine (AlSPc) in dimethylhydrazine induced colonic tumours and adjacent normal colon in rats. Forty eight hours after intravenous injection, most tumours contained twice as much AlSPc as normal colon. Tumour size and position in the colon did not affect AlSPc concentration. Microscopic fluorescence localisation of AlSPc showed significant photosensitiser accumulation in tumour stroma, whereas tumour and normal mucosa contained similar amounts. Thus, some normal tissue damage, where malignant cells invade normal areas, would inevitably accompany eradication of tumours. Tumour destruction and healing of colon after tumour eradication were examined histologically. There was sharp demarcation between necrotic areas (tumour or normal) and adjacent tissue and, whether the treated area was tumour or normal, healing occurred by regeneration of normal tissue. Some incompletely eradicated large tumours showed evidence of delayed bleeding. The possibility of selective uptake or preferential retention of the photosensitiser in tumours formed the initial basis for investigation of photodynamic therapy, but it is now clear that this is seldom the most important factor for tumour eradication. Of far greater importance is the nature of the biological effect of photodynamic therapy as necrosis of small tumours involving the full thickness of the bowel wall can be achieved with safe healing by regeneration of normal colon. The maximum depth of necrosis produced was only a few millimetres, so this technique is unlikely to be of value as the primary treatment for large colonic tumours but may prove of value for eradicating small lesions or as adjunctive therapy for eradication of small nests of tumour remaining or recurring in the tumour bed after conventional surgery.
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Affiliation(s)
- H Barr
- National Medical Laser Centre, Department of Surgery, Rayne Institute, London
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