Applications of Photosensitisers to Cancer, Viral, Bacterial Disease and Immunology Terry Wright http://www.cytoluminator.com
Non-toxic Sensitizer Cell Survives Photosensitising agent Dye molecule Not cytotoxic Taken up by cell (i.e. staining) Cell Cell Survives
Tuned Laser Light Cell Survives Light exposure Red or near IR Light (Red) Light exposure Red or near IR Cell is transparent Not cytotoxic No heating Cell Cell Survives
Cell Dies!! ROS Flood = Death PS + Light Cell not transparent Light (Red) PS + Light Cell not transparent Energy is absorbed Reactive oxygen species Oxidative stress Cell Cell Dies!!
Chemical Targeting
Nanomolecular Delivery Proprietary sensitiser formulation 20 nm nanoparticles containing sensitiser Cationic surface charge targets cancer Reduced sensitisation of healthy tissue Eyes Skin Rapid clearance 1wk vs 6
Nanomolecular Delivery Accumulation of sensitizer in skin of Bufo Marinus with nanomolecule Same sensitizer and same dose without nanomolecule formula
Gentle Death High dose: necrosis Minimum dose: apoptosis Sensitiser bound to mitochondrial membrane Cleave Bcl-2 / Bcl-XL Loss of mitochondrial membrane potential Programmed cell death follows
S. S. Stylli and A. H. Kaye, J. Clin. Neurosci. 13, 709-717 (2006) PDT of Cancer Barret’s Oesophagus Adjunct therapy for solid tumours Systemic administration Non-surgical debulking Killing microscopic remnants Topical application for non-melanoma SC Glioblastoma Multiforme at RMH 50% survival at 10 yr, vs ~5% at 2 yr chemo S. S. Stylli and A. H. Kaye, J. Clin. Neurosci. 13, 709-717 (2006)
PDT Causes in-situ Vaccination Adaptive immunity frequently observed Remote metastases controlled / eliminated Tc / NK cells, macrophages Animal models resistant to rechallenge Adoptively transferable Inflammation due to necrosis, immune response due to apoptosis? F.H. van Duijnhoven et al., Immunobiol. 207, 105-113 (2003).
Activating the Immune System Because PDT creates a perfect vaccination against the cancer in the patients body, the immune system immediately begins to attack the cancer. With antibody therapy the suppressor t-cells are activated. When killing a large tumor up to 95% of the bodies white cells rush to attack the cancer
Disabling the Defense Cancer mounts a defense against the immune system. T-cells are converted to suppressor cells which suppress new TIL. Immature myeloid cells are converted to suppressors via ROS. Antibodies disable the defense systems mounted by cancer to enable immune attack
Risk Factors with PDT High level necrotic kills can cause swelling and inflammation- severe risk for brain tumors. Even with apoptotic kills the amount of cancer killed can be huge. Toxin load can be challenging for hepatic and renal elimination, so maintainance of organ health is vital.
Absorption/Fluorescence Spectra λ = 685 nm (excitation) Fluorescence detection Absorption Emission
Detection of Fluorescence Laser excitation Near-IR fluorescence Camera with IR filter Laser: 685nm IR: 695-780nm
Image on PC Screen
Lymphatic Involvement When cancer is not present in lymph nodes, no fluorescence is seen, as in the left picture above. When cancer is present, photodynamic fluorescence is very obvious. A few minutes of laser will resolve this condition.
Metastatic Bone Cancer Patient 2: metastasis in the manubrium Before Treatment After Treatment
Metastatic Bone Cancer Skull mets Ankle mets
Post-Salvage Breast Cancer Following surgery, chemotherapy and radiotherapy
Post-Salvage Breast Cancer Following Photodynamic Therapy
Post-Salvage Breast Cancer
Psoriasis Active leukocytes accumulate sensitiser Topical PDT of skin autoimmune disorders Psoriasis treated with our sensitiser Two weeks later
Scleroderma treated with our sensitiser Scleroderma Treated over two years ago No indication of return to date Scleroderma treated with our sensitiser
Multiple Sclerosis Before treatment After treatment Multiple Sclerosis treatment is remarkably easy. A one hour infusion with laser illumination at the same time resets the immune system resulting in long lasting remission of symptoms
Diabetes Diabetes Mellitus type I has been treated in animal models. Mice genetically programmed to develop DM I treated with PDT have a 60% lower chance of developing DM I. Both types of Diabetes are now being considered as autoimmune diseases. In one diabetic patient treated for cancer, blood sugar levels dropped from 10+ to six range within days after treatment.
Diabetic Wound Healing Wounds which normally don’t heal for days or weeks can be treated with a topical application of sensitizer and a few minutes of laser. Wound healing proceeds normally after treatment
Bacteria Golden Staph has been tested to 20 generations of LD 50 kills It has never shown indication of developing resistance to PDT. PDT for golden staph can be delivered fast and cost effectively. In Staph from recent injuries or surgeries, the sensitizer can be administered topically and will absorb through the wound. Bloodborne golden staph can be treated with IV infusions.
Conclusion PDT: a clinical reality in most developed countries But Australia is trailing ~15 years behind No sensitiser approved for systemic use Locally developed and manufactured: Portable laser, >5W at present and >10W planned Photosensitisers: systemic, intratumoural, topical IR camera and uniform illumination
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