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Unique diagnostic and therapeutic roles of porphyrins and phthalocyanines in photodynamic therapy, imaging and theranostics.

Josefsen LB, Boyle RW - Theranostics (2012)

Bottom Line: Porphyrinic molecules have a unique theranostic role in disease therapy; they have been used to image, detect and treat different forms of diseased tissue including age-related macular degeneration and a number of different cancer types.Current focus is on the clinical imaging of tumour tissue; targeted delivery of photosensitisers and the potential of photosensitisers in multimodal biomedical theranostic nanoplatforms.The roles of porphyrinic molecules in imaging and pdt, along with research into improving their selective uptake in diseased tissue and their utility in theranostic applications are highlighted in this Review.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, The University Of Hull, Kingston-Upon-Hull, HU6 7RX, U.K.

ABSTRACT
Porphyrinic molecules have a unique theranostic role in disease therapy; they have been used to image, detect and treat different forms of diseased tissue including age-related macular degeneration and a number of different cancer types. Current focus is on the clinical imaging of tumour tissue; targeted delivery of photosensitisers and the potential of photosensitisers in multimodal biomedical theranostic nanoplatforms. The roles of porphyrinic molecules in imaging and pdt, along with research into improving their selective uptake in diseased tissue and their utility in theranostic applications are highlighted in this Review.

No MeSH data available.


Related in: MedlinePlus

Clinical Procedure For Pdt.
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Figure 4: Clinical Procedure For Pdt.

Mentions: Porphyrins and PCs have been widely investigated for use in photodynamic therapy (pdt). Pdt is used clinically in the treatment of a number of medical conditions, including age-related macular degeneration (AMD), some cancers, skin conditions and for antiviral, antimicrobial and antibacterial applications including sterilisation of blood plasma and water 3-5, 7, 14, 24-30. The first recorded use of “phototherapy” dates back over 4000 years to the ancient Egyptians while contemporary pdt was first reported in the late 19th century by Finsen et al. 3, 4, 13-15, 24, 28, 31, 32. Finsen was later awarded the Nobel Prize (1903) for his work in pdt. However, it was not until 1995 that a suitable photosensitiser was approved (Photofrin®, by the Food and Drug Administration (FDA), USA) for clinical use against certain cancers 4, 5, 14, 24, 25, 27, 28, 32-34. Pdt is minimally invasive and shows negligible toxicity thus offering advantages for both the patient and physician over traditional cancer treatments such as delicate surgery, or painful and tiring radio- and chemo-therapy. Lengthy recuperation periods are also minimised, along with minimal formation of scar tissue and disfigurement. However, pdt is not without its drawbacks - it is associated with generalised photosensitisation of cutaneous tissue, this is a major limitation in the potential efficacy of pdt 3, 24, 27, 28. The principle behind pdt is based on a multi-stage process (figure 4) whereby (i) a photosensitiser is administered to the patient (systemically or topically) in the absence of light. When the optimum ratio of photosensitiser in diseased verses healthy tissue is achieved (ii) the photosensitiser is activated by (iii) exposure to a carefully regulated dose of light, which is shone directly onto the diseased tissue for a specified length of time. The activated photosensitiser then reacts with molecular oxygen generating reactive oxygen species (ROS) in situ, evoking a toxic response in the tissue, culminating ultimately in (iv) cell death 4, 5, 35. The success of pdt lies in the prolonged accumulation of the photosensitiser in diseased tissue, relative to more rapid clearance from healthy tissue. The selectivity of pdt is based on the ability of the photosensitiser to preferentially accumulate in the diseased tissue and efficiently generate singlet oxygen (the cytotoxic species), inducing cell death.


Unique diagnostic and therapeutic roles of porphyrins and phthalocyanines in photodynamic therapy, imaging and theranostics.

Josefsen LB, Boyle RW - Theranostics (2012)

Clinical Procedure For Pdt.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475217&req=5

Figure 4: Clinical Procedure For Pdt.
Mentions: Porphyrins and PCs have been widely investigated for use in photodynamic therapy (pdt). Pdt is used clinically in the treatment of a number of medical conditions, including age-related macular degeneration (AMD), some cancers, skin conditions and for antiviral, antimicrobial and antibacterial applications including sterilisation of blood plasma and water 3-5, 7, 14, 24-30. The first recorded use of “phototherapy” dates back over 4000 years to the ancient Egyptians while contemporary pdt was first reported in the late 19th century by Finsen et al. 3, 4, 13-15, 24, 28, 31, 32. Finsen was later awarded the Nobel Prize (1903) for his work in pdt. However, it was not until 1995 that a suitable photosensitiser was approved (Photofrin®, by the Food and Drug Administration (FDA), USA) for clinical use against certain cancers 4, 5, 14, 24, 25, 27, 28, 32-34. Pdt is minimally invasive and shows negligible toxicity thus offering advantages for both the patient and physician over traditional cancer treatments such as delicate surgery, or painful and tiring radio- and chemo-therapy. Lengthy recuperation periods are also minimised, along with minimal formation of scar tissue and disfigurement. However, pdt is not without its drawbacks - it is associated with generalised photosensitisation of cutaneous tissue, this is a major limitation in the potential efficacy of pdt 3, 24, 27, 28. The principle behind pdt is based on a multi-stage process (figure 4) whereby (i) a photosensitiser is administered to the patient (systemically or topically) in the absence of light. When the optimum ratio of photosensitiser in diseased verses healthy tissue is achieved (ii) the photosensitiser is activated by (iii) exposure to a carefully regulated dose of light, which is shone directly onto the diseased tissue for a specified length of time. The activated photosensitiser then reacts with molecular oxygen generating reactive oxygen species (ROS) in situ, evoking a toxic response in the tissue, culminating ultimately in (iv) cell death 4, 5, 35. The success of pdt lies in the prolonged accumulation of the photosensitiser in diseased tissue, relative to more rapid clearance from healthy tissue. The selectivity of pdt is based on the ability of the photosensitiser to preferentially accumulate in the diseased tissue and efficiently generate singlet oxygen (the cytotoxic species), inducing cell death.

Bottom Line: Porphyrinic molecules have a unique theranostic role in disease therapy; they have been used to image, detect and treat different forms of diseased tissue including age-related macular degeneration and a number of different cancer types.Current focus is on the clinical imaging of tumour tissue; targeted delivery of photosensitisers and the potential of photosensitisers in multimodal biomedical theranostic nanoplatforms.The roles of porphyrinic molecules in imaging and pdt, along with research into improving their selective uptake in diseased tissue and their utility in theranostic applications are highlighted in this Review.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, The University Of Hull, Kingston-Upon-Hull, HU6 7RX, U.K.

ABSTRACT
Porphyrinic molecules have a unique theranostic role in disease therapy; they have been used to image, detect and treat different forms of diseased tissue including age-related macular degeneration and a number of different cancer types. Current focus is on the clinical imaging of tumour tissue; targeted delivery of photosensitisers and the potential of photosensitisers in multimodal biomedical theranostic nanoplatforms. The roles of porphyrinic molecules in imaging and pdt, along with research into improving their selective uptake in diseased tissue and their utility in theranostic applications are highlighted in this Review.

No MeSH data available.


Related in: MedlinePlus