[Photodynamic therapy-trends and new developments]

Basal cell carcinoma arising within nevus sebaceous on the right scalp in a 55-year-old male: A case report and review of literature

We report here a case of nevus sebaceous in a 55-year-old male, who presented with a 50-year history of an asymptomatic swelling in his right scalp. The solitary, yellowish, expansile plaque over the scalp gradually became lobulated and turned dark-pigmented with spontaneous bleeding, itching discomfort, and occasional ulceration after scratching. The male's clinical presentation and histopathological findings were compatible with basal cell carcinoma arising in nevus sebaceous. At present, 5-aminolevulinic acid photodynamic therapy (ALA-PDT) emerges as a novel treatment modality which has proved safe and effective. In this case, three sessions of photodynamic therapy in combination with surgical excision were performed, leaving mild pigmentation within 3 weeks. The patient showed good cosmetic outcome, minimal scarring on the right scalp without further complications, disease recurrence or metastasis after ALA-PDT within six months.

Efficacy of photodynamic therapy in the treatment of venous trophic ulcers: results from the experiment

Introduction. Today, antimicrobial photodynamic therapy (a-PDT) becomes more and more popular, because of it pronounced bactericidal activity, anti-inflammatory effect. At the same time, no animal model studies have been conducted on morphological changes in cells after exposure to PDT on venous ulcers (VU) when using different types of photosensitizers (PS). The problem of comparing morphological changes in tissues when using a-PDT vs conventional PDT have not yet been resolved.

Aim. Evaluation of the effectiveness of PDT and APDT in a comprehensive examination of trophic ulcers in an in vivo experiment and compare them with standard methods for the treatment of VLU.

Materials and мethods. A series of experiments was conducted on 21 rabbits, separated into 3 equal groups of 7 rabbits each. Venous trophic ulcer was originally modeled for all rabbits. To obtain a VU, we performed an additional ligation of v. femoralis. The control group received standard therapy for VU. The PDT group had PDT with Photosens. The a-PDT group underwent a-PDT using Cholosens. Every 3 days, picture of local inflammation, regeneration rate and ulcer volume were determined. A morphological study of VLU was carried out on the first, 9th and 15th days.

Results. The a-PDT group, day 15: 100% wound epithelization. Control group, day 21st: The volume of wounds decreased on average by 50%. The PDT group: 100% wound epithelization. The morphological study indicated a positive trend in the a-PDT group compared with PDT and control groups, which resulted in a decrease in the total mass of necrotic detritus, a change in the quantitative and qualitative composition of inflammatory infiltrate.

Conclusion. The data obtained indicate that the use of a-PDT is recommended in treatment of VLU. Both PDT and a-PDT methods showed better results in comparison with standard therapy.

The photosensitizer-based therapies enhance the repairing of skin wounds

Wound repair remains a clinical challenge and bacterial infection is a common complication that may significantly delay healing. Therefore, proper and effective wound management is essential. The photosensitizer-based therapies mainly stimulate the photosensitizer to generate reactive oxygen species through appropriate excitation source irradiation, thereby killing pathogenic microorganisms. Moreover, they initiate local immune responses by inducing the recruitment of immune cells as well as the production of proinflammatory cytokines. In addition, these therapies can stimulate the proliferation, migration and differentiation of skin resident cells, and improve the deposition of extracellular matrix; subsequently, they promote the re-epithelialization, angiogenesis, and tissue remodeling. Studies in multiple animal models and human skin wounds have proved that the superior sterilization property and biological effects of photosensitizer-based therapies during different stages of wound repair. In this review, we summarize the recent advances in photosensitizer-based therapies for enhancing tissue regeneration, and suggest more effective therapeutics for patients with skin wounds.

Latest Innovations and Nanotechnologies with Curcumin as a Nature-Inspired Photosensitizer Applied in the Photodynamic Therapy of Cancer

In the context of the high incidence of cancer worldwide, state-of-the-art photodynamic therapy (PDT) has entered as a usual protocol of attempting to eradicate cancer as a minimally invasive procedure, along with pharmacological resources and radiation therapy. The photosensitizer (PS) excited at certain wavelengths of the applied light source, in the presence of oxygen releases several free radicals and various oxidation products with high cytotoxic potential, which will lead to cell death in irradiated cancerous tissues. Current research focuses on the potential of natural products as a superior generation of photosensitizers, which through the latest nanotechnologies target tumors better, are less toxic to neighboring tissues, but at the same time, have improved light absorption for the more aggressive and widespread forms of cancer. Curcumin incorporated into nanotechnologies has a higher intracellular absorption, a higher targeting rate, increased toxicity to tumor cells, accelerates the activity of caspases and DNA cleavage, decreases the mitochondrial activity of cancer cells, decreases their viability and proliferation, decreases angiogenesis, and finally induces apoptosis. It reduces the size of the primary tumor, reverses multidrug resistance in chemotherapy and decreases resistance to radiation therapy in neoplasms. Current research has shown that the use of PDT and nanoformulations of curcumin has a modulating effect on ROS generation, so light or laser irradiation will lead to excessive ROS growth, while nanocurcumin will reduce the activation of ROS-producing enzymes or will determine the quick removal of ROS, seemingly opposite but synergistic phenomena by inducing neoplasm apoptosis, but at the same time, accelerating the repair of nearby tissue. The latest curcumin nanoformulations have a huge potential to optimize PDT, to overcome major side effects, resistance to chemotherapy, relapses and metastases. All the studies reviewed and presented revealed great potential for the applicability of nanoformulations of curcumin and PDT in cancer therapy.