Globus Lucidus: A porcine study of an intracranial implant designed to deliver closed, repetitive photodynamic and photochemical therapy in glioblastoma

OBJECTIVE

Herein we describe initial results in a porcine model of a fully implantable device designed to allow closed, repetitive photodynamic treatment of glioblastoma (GBM).

METHODS

This implant, Globus Lucidus, is a transparent quartz glass sphere with light-emitting diodes releasing wavelengths of 630 nm (19.5 mW/cm2), 405 nm (5.0 mW/cm2) or 275 nm (0.9 mW/cm2). 5-aminolevulinic acid was the photosensitizing prodrug chosen for use with Globus Lucidus, hence the implants illuminated at 630 nm or 405 nm. An additional 275 nm wavelength-emittance was included to explore the effects of photochemical therapy (PCT) by ultraviolet (UV) light. Twenty healthy domestic pigs underwent right-frontal craniotomies. The Globus Lucidus device was inserted into a surgically created right-frontal lobe cavity. After postoperative recovery, irradiation for up to 30 min daily for up to 14 d, or continuous irradiation for up to 14.6 h was conducted.

RESULTS

Surgery, implants, and repeated irradiations using the different wavelengths were generally well tolerated. Social behavior, wound healing, body weight, and temperature remained unaffected. Histopathological analyses revealed consistent leukocyte infiltration around the intracerebral implant sites with no significant differences between experimental and control groups.

CONCLUSION

This Globus Lucidus porcine study prepares the groundwork for adjuvant, long-term, repeated PDT of the GBM infiltration zone. This is the first report of a fully implantable PDT/PCT device for the potential treatment of GBM. A preclinical effectivity study of Globus Lucidus PDT/PCT is warranted and in advanced stages of planning.

A Comprehensive Review of Various Therapeutic Strategies for the Management of Skin Cancer

Skin cancer (SC) poses a global threat to the healthcare system and is expected to increase significantly over the next two decades if not diagnosed at an early stage. Early diagnosis is crucial for successful treatment, as the disease becomes more challenging to cure as it progresses. However, identifying new drugs, achieving clinical success, and overcoming drug resistance remain significant challenges. To overcome these obstacles and provide effective treatment, it is crucial to understand the causes of skin cancer, how cells grow and divide, factors that affect cell growth, and how drug resistance occurs. In this review, we have explained various therapeutic approaches for SC treatment via ligands, targeted photosensitizers, natural and synthetic drugs for the treatment of SC, an epigenetic approach for management of melanoma, photodynamic therapy, and targeted therapy for BRAF-mutated melanoma. This article also provides a detailed summary of the various natural drugs that are effective in managing melanoma and reducing the occurrence of skin cancer at early stages and focuses on the current status and future prospects of various therapies available for the management of skin cancer.

A Phototheranostic Strategy to Continuously Deliver Singlet Oxygen in the Dark and Hypoxic Tumor Microenvironment

Continuous irradiation during photodynamic therapy (PDT) inevitably induces tumor hypoxia, thereby weakening the PDT effect. In PDT-induced hypoxia, providing singlet oxygen from stored chemical energy may enhance the cell-killing effect and boost the therapeutic effect. Herein, we present a phototheranostic (DPPTPE@PEG-Py NPs) prepared by using a 2-pyridone-based diblock polymer (PEG-Py) to encapsulate a semiconducting, heavy-atom-free pyrrolopyrrolidone-tetraphenylethylene (DPPTPE) with high singlet-oxygen-generation ability both in dichloromethane and water. The PEG-Py can trap the 1 O2 generated from DPPTPE under laser irradiation and form a stable intermediate of endoperoxide, which can then release 1 O2 in the dark, hypoxic tumor microenvironment. Furthermore, fluorescence-imaging-guided phototherapy demonstrates that this phototheranostic could completely inhibit tumor growth with the help of laser irradiation.

Clinical Trials and Basic Research in Photodynamic Diagnostics and Therapies from the Center for Laser Diagnostics and Therapy in Poland

The purpose of this review is to present an overview of the development of photodiagnostic and photodynamic therapy (PDD and PDT) techniques in Poland. The paper discusses the principles of PDD, including fluorescent techniques in determining precancerous conditions and cancers of the skin, digestive tract, bladder and respiratory tract. Methods of PDT of cancer will be discussed and the current state of knowledge as well as future trends in the development of photodynamic techniques will be presented, including the possibility of using photodynamic antimicrobial therapy. Research pioneers in photodynamic medicine such as Thomas Dougherty are an inspiration for the development of methods of PDD and PDT in our Clinic. The Center for Laser Diagnostics and Therapy in Bytom, Poland, promotes the propagation of PDD and PDT through the training of clinicians and raising awareness among students in training and the general public. Physicians at the Center are engaged in photomedical research aimed at clinical implementation and exploration of new avenues in photomedicine while optimizing existing modalities. The Center promotes dissemination of clinical results from a wide range of topics in PDD and PDT and serving as representative authorities of photodynamic medicine in Poland and Europe.

High-power light-emitting diode array design and assembly for practical photodynamic therapy research

SIGNIFICANCE

Commercial lasers, lamps, and light-emitting diode (LED) light sources have stimulated the clinical translation of photodynamic therapy (PDT). Yet, the continued exploration of new photosensitizers (PSs) for PDT often requires separate activation wavelengths for each agent being investigated. Customized light sources for such research frequently come at significant financial or technical cost, especially when compounded over many agents and wavelengths.

AIM

LEDs offer potential as a cost-effective tool for new PS and multi-PS photodynamic research. A low-cost-per-wavelength tool leveraging high-power LEDs to facilitate efficient and versatile research is needed to further accelerate research in the field.

APPROACH

We developed and validated a high-power LED array system for benchtop PDT with a modular design for efficient switching between wavelengths that overcome many challenges in light source design. We describe the assembly of a low-cost LED module plus the supporting infrastructure, software, and protocols to streamline typical in vitro PDT experimentation.

RESULTS

The LED array system is stable at intensities in excess of 100  mW  /  cm2 with 2.3% variation across the illumination field, competitive with other custom and commercial devices. To demonstrate efficacy and versatility, a primary ovarian cancer cell line was treated with two widely used PSs, aminolevulinic acid and verteporfin, using the LED modules at a clinically relevant 50  J  /  cm2 light dose that induced over 90% cell death for each treatment.

CONCLUSIONS

Our work provides the community with a tool for new PS and multi-PS benchtop photodynamic research that, unlike most commercial light sources, affords the user a low barrier to entry and low-cost-per-wavelength with the goal of illuminating new insights at the forefront of PDT.