Photodynamic therapy systems and applications

Theranostic Uses of the Heme Pathway in Neuro-Oncology: Protoporphyrin IX (PpIX) and Its Journey from Photodynamic Therapy (PDT) through Photodynamic Diagnosis (PDD) to Sonodynamic Therapy (SDT)

ALA PDT, first approved as a topical therapy to treat precancerous skin lesions in 1999, targets the heme pathway selectively in cancers. When provided with excess ALA, the fluorescent photosensitizer PpIX accumulates primarily in cancer tissue, and ALA PDD is used to identify bladder and brain cancers as a visual aid for surgical resection. ALA PDT has shown promising anecdotal clinical results in recurrent glioblastoma multiforme. ALA SDT represents a noninvasive way to activate ALA PDT and has the potential to achieve clinical success in the treatment of both intracranial and extracranial cancers. This review describes the creation and evolution of ALA PDT, from the treatment of skin cancers to PDD and PDT of malignant brain tumors and, most recently, into a noninvasive form of PDT, ALA SDT. Current clinical trials of ALA SDT for recurrent glioblastoma and high-grade gliomas in adults, and the first pediatric ALA SDT clinical trial for a lethal brainstem cancer, diffuse intrinsic pontine glioma (DIPG), are also described.

Mitochondrial dysfunction mediates neuronal cell response to DMMB photodynamic therapy

Photodynamic therapy (PDT) is a process in which a photosensitizer (PS) is exposed to specific wavelengths and generates reactive oxygen species (ROS) which act within nanometers. The low invasive nature and directed cytotoxicity of this approach render it attractive to the treatment of different conditions, including the ones that affect the central nervous system (CNS). The effect of PDT on healthy neurons is one main concern over its use in the CNS, since neuronal-like cells were shown to be particularly sensitive to certain PSs. Among available PSs, 1,9-dimethyl-methylene blue (DMMB) stands out as being resistant to reduction to its inactive leuco form and by being able to produce high levels of singlet‑oxygen. In this study, we aimed to investigate DMMB photodamage mechanisms in the hippocampal cell line HT22. Our results demonstrate that DMMB-PDT decrease in cell viability was linked with an increase in cell death and overall ROS production. Besides, it resulted in a significant increase in mitochondrial ROS production and decreased mitochondria membrane potential. Furthermore, DMMB-PDT significantly increased the presence of acidic autolysosomes, which was accompanied by an increase in ATG1 and ATG8 homologue GaBarap1 expression, and decreased DRAM1 expression. Taken together our results indicated that mitochondrial and autophagic dysfunction underlie DMMB-PDT cytotoxicity in neuronal cells.

The Use of Photodynamic Therapy in the Treatment of Brain Tumors-A Review of the Literature

The treatment of neoplastic disease of the brain is still a challenge for modern medicine. Therefore, advanced methodologies are needed that can rationally and successfully contribute to the early diagnosis of primary and metastatic tumors growing within the brain. Photodynamic therapy (PDT) seems to be a valuable method of treatment for precancerous and cancerous lesions including brain tumors. The main advantage of PDT is its high efficiency, minimal invasiveness and no serious side effects, compared with chemotherapy and radiotherapy. This review was conducted through a comprehensive search of articles, scientific information databases and the websites of organizations dealing with cancer treatment. Key points from clinical trials conducted by other researchers are also discussed. The common databases such as PubMed, Google Scholar, EBSCO, Scopus, and Elsevier were used. Articles in the English language of reliable credibility were mainly analyzed. The type of publications considered included clinical and preclinical studies, systematic reviews, and case reports. Based on these collected materials, we see that scientists have already demonstrated the potential of PDT application in the field of brain tumors. Therefore, in this review, the treatment of neoplasm of the Central Nervous System (CNS) and the most common tumor, glioblastoma multiforme (GBM), have been explored. In addition, an overview of the general principles of PDT, as well as the mechanism of action of the therapy as a therapeutic platform for brain tumors, is described. The research was carried out in June 2022.

Two cationic meso-thiophenium porphyrins and their zinc-complexes as anti-HIV-1 and antibacterial agents under non-photodynamic therapy (PDT) conditions

The anti-HIV-1 and antimicrobial activities of novel cationic meso-thiophenium porphyrins and their zinc-complex are reported under in vitro non-photodynamic (PDT) conditions. While all the cationic porphyrins led to the inhibition of de novo virus infection, the Zn(II)-complexes of T₂(OH)₂M (A₂B₂-type) and T(OH)₃M (AB₃-type) displayed potent inhibition of HIV-1 entry with T₂(OH)₂MZn displaying maximal anti-HIV activity. The Zinc complex of both the thiophenium porphyrins T₂(OH)₂M and T(OH)₃M also depicted antibacterial activities against Escherichia coli (ATCC 25922) and more prominently against Staphylococcus aureus (ATCC 25923). Again, the antibacterial activity was more potent for T₂(OH)₂MZn. Our study highlighted that the presence of two thiophenium groups at the meso-positions of the A₂B₂-type porphyrins along with zinc strongly enhanced anti-HIV and antimicrobial properties of these novel thiophenium porphyrins under non-PDT conditions.

An Anti-inflammatory Fe3 O4 -Porphyrin Nanohybrid Capable of Apoptosis through Upregulation of p21 Kinase Inhibitor Having Immunoprotective Properties under Anticancer PDT Conditions

We report the influence of Fe₃ O₄ nanoparticles (NPs) on porphyrins in the development of photosensitizers (PSs) for efficient photodynamic therapy (PDT) and possible post-PDT responses for inflicting cancer cell death. Except for Au, most metal-based nanomaterials are unsuitable for clinical applications. The US Food and Drug Administration and other agencies have approved Feraheme and a few other iron oxide NPs for clinical use, paving the way for novel biocompatible immunoprotective superparamagnetic iron oxide nanohybrids to be developed as nanotherapeutics. A water-soluble nanohybrid, referred to here as E-NP, comprising superparamagnetic Fe₃ O₄ NPs functionalised with tripyridyl porphyrin PS was introduced through a rigid 4-carboxyphenyl linker. As a PDT agent, the efficacy of E-NP toward the AGS cancer cell line showed enhanced photosensitising ability as determined through in vitro photobiological assays. The cellular uptake of E-NPs by AGS cells led to apoptosis by upregulating ROS through cell-cycle arrest and loss of mitochondrial membrane potential. The subcellular localisation of the PSs in mitochondria stimulated apoptosis through upregulation of p21, a proliferation inhibitor capable of preventing tumour development. Under both PDT and non-PDT conditions, this nanohybrid can act as an anti-inflammatory agent by decreasing the production of NO and superoxide ions in murine macrophages, thus minimising collateral damage to healthy cells.

One ring is not enough to rule them all. Albumin-dependent ABCG2-mediated transport of chlorophyll-derived photosensitizers

Breast cancer resistance protein (BCRP, ABCG2) is a member of the ATP-binding-cassette (ABC) superfamily of membrane transporters. It is involved in the efflux of a broad range of xenobiotics of highly diverse structures. BCRP activity greatly influences drug distribution in vivo and is often associated with cancer multidrug resistance, which is observed in the case of both chemotherapy and photodynamic therapy. The set of ABCG2 substrates includes porphyrins and chlorins such as heme, hemin, protoporphyrin IX, chlorin e6, pheophorbide a, and their derivatives. Here we provide an evidence that magnesium- and zinc-substituted derivatives of pheophorbide a, which are very promising photosensitizers for use in photodynamic therapy, are also recognized and transported by ABCG2. Interestingly, despite minor structural differences, they clearly differ in the transport rate, both between each other and compared to pheophorbide a. In addition, their transport rate, like those of other structurally similar compounds, is strictly dependent on the level of serum albumin in the extracellular environment. The results that we present here are crucial for the use of metal-substituted pheophorbides in clinical practice but also provide an important insight into the mechanism of porphyrin transport by ABCG2.

The potential of photodynamic therapy in current breast cancer treatment methodologies

Photodynamic Therapy (PDT) has been known for over a hundred years, and currently gaining in acceptance as an alternative cancer treatment. Light delivery is still a difficult problem in deep cancer treatment with PDT. Only near-infrared light in the 700-1100 nm range can penetrate deeply into the tissue because most tissue chromophores, including oxyhemoglobin, deoxyhemoglobin, melanin and fat, poorly absorb in the near infrared window. The light sources used in PDT are lasers, arc lamps, light-emitting diodes and fluorescent lamps. PDT has been used for many different clinical applications. PDT may be excellent alternative in the treatment and diagnosis of breast cancer compared to the conventional surgery, chemotherapy and radiotherapy. The basic elements of PDT are an appropriate photosensitizer (PS), oxygen, and light. The effectiveness of photodynamic therapy depends on the induction of photocytotoxic reactions, which are the result of light activation of PS), pre-administered to the body. The condition for initiating PDT processes is light absorption by PS and subsequent localized generation of cytotoxic reactive oxygen species. This study is a review of empirical research aimed at improving the therapy and diagnosis of breast cancer using PDT based on the physicochemical differences in healthy and diseased tissues and the tissues undergoing treatment.

Dual activity of amphiphilic Zn(II) nitroporphyrin derivatives as HIV-1 entry inhibitors and in cancer photodynamic therapy

Two Zn(II) nitro porphyrin derivatives bearing combinations of meso-4-nitrophenyl and meso-4-methylpyridinium moieties and their free-base precursors were synthesized through one-pot microwave process, purified and characterized. The biological activity of these nitroporphyrins was assessed under both photodynamic and non-photodynamic conditions to correlate their structure-activity relationship (SAR). Unlike, the free-base precursors, Zn(II) complexes of these nitroporphyrins displayed nearly complete inhibition in the entry of lentiviruses such as HIV-1 and SIVmac under non-photodynamic conditions. In addition, the Zn(II) complexes also exhibited a higher in vitro photodynamic activity towards human lung cancer cell-line A549 than their free-base precursors. Our results strongly suggest that incorporation of Zn(II) has improved the antiviral and anticancer properties of the nitroporphyrins. To the best of our knowledge, this is the first report demonstrating the dual activity of nitroporphyrin-zinc complexes as antiviral and anti-cancer, which will aid in their development as therapeutics in clinics.

Benzamide porphyrins with directly conjugated and distal pyridyl or pyridinium groups substituted to the porphyrin macrocycles: Study of the photosensitising abilities as inducers of apoptosis in cancer cells under photodynamic conditions

Amphiphilic porphyrin photosensitisers (PSs) having combinations of directly substituted pyridyl group(s) at the meso-position of a porphyrin macrocycle, and/or indirectly linked pyridyl groups as benzamide derivatives are reported. The compounds 5,10,15,20-tetrakis-(4-pyridylbenzamide)porphyrin (A.2), 5,10,15,20-tetra[N-(pyridine-4-yl)benzamidium] porphyrin (A.3), 5-mono-(4-pyridyl)-10,15,20-tris-(4-pyridylbenzamide)porphyrin (B.2) and 5-mono-(4-methylpyridinium)-10,15,20-tris-(4-pyridiniumbenzamide)porphyrin (B.3) were synthesised. The compounds were successfully characterised through UV-Vis, Emission, ¹H NMR, and ESI-HRMS techniques. To evaluate the effect of this combination of directly conjugated and non-conjugated pyridyl/cationic pyridinium groups on the porphyrin macrocycle, the efficacy of the synthesised compounds was compared to a known standard 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP). These compounds show better efficacy (IC₅₀'s ranging between 0.66±0.04μM to 3.71±1.01μM) against A549 (human epithelial adenocarcinoma lung cancer) cell line under in vitro photodynamic conditions in comparison to MDA-MB-231 (breast cancer) (IC₅₀'s ranging between 3.7±0.087μM to 12.1±0.12μM) and Pa-1 (ovarian cancer) (IC₅₀'s ranging between 17.9±0.01μM to 42.45±0.02μM) cell lines. It was found that B.3, having a pyridinium group attached to the meso-position of the macrocycle along with three distal cationic pyridinium groups, independent of the porphyrinic electron delocalisation cycle, showed better photocytotoxic efficacy (IC₅₀=0.66±0.04μM, A549 lung cancer cell line) and higher potential to promote apoptosis and hence better efficacy as PS towards cancer photodynamic therapy (PDT). The PDT activity of B.3 was further verified and established by various biological assays, viz. Annexin V assay, cell cycle assay, and reactive oxygen species (ROS) activity assay.

The susceptibility of dermatophytes to photodynamic treatment with special focus on Trichophyton rubrum

Owing to the accessibility of skin to light, many applications of photodynamic treatment (PDT) have been developed within dermatology. The recent increase of dermatological antimicrobial PDT investigations is related to the growing problem of bacterial and fungal resistance to antibiotics. This review focuses on the susceptibility of dermatophytic fungi, in particular Trichophyton rubrum, to PDT and shows its potential usefulness in treatment of clinical dermatophytoses. There are no data indicating significant differences in PDT susceptibility between various dermatophytes and it is unlikely that treatment problems of especially T. rubrum with current antimycotics would occur in case of PDT. Red light 5-aminolevulinic acid-mediated PDT is after repeated sessions successful in in vivo treatment of onychomycosis (fungal nail infection) caused by various dermatophytes. Regarding skin dermatophytoses, UVA-1 PDT with cationic porphyrins appears to be safe and efficient. Most effective toward T. rubrum ex vivo is 5,10,15-tris(4-methylpyridinium)-20-phenyl-[21H,23H]-porphine trichloride (Sylsens B) when combined with UVA-1 radiation or red light; this creates the possibility of efficiently treating nail infections and remaining spores in hair follicles. If the promising in vitro and ex vivo results could be transferred to clinical practice, then PDT has a good prospect to become a worthy alternative to established antifungal drugs.

In vitro and in vivo matrix metalloproteinase expression after photodynamic therapy with a liposomal formulation of aminolevulinic acid and its methyl ester

Photodynamic therapy (PDT) is a well-known method for the treatment of malignant tumors, and its principles have been well established over the past 30 years. This therapy involves the application of a chemical called a photosensitizer and its subsequent excitation with light at the appropriate wavelength and energy. Topical photodynamic therapy with aminolevulinic acid (5-ALA) is an alternative therapy for many malignant processes, including nonmelanoma skin cancers such as basal-cell carcinoma (BCC). Our novel approach for this study was to use a liposomal formulation of 5-ALA and its methyl ester (commercially available as metvix) both in vitro and in vivo, and to check whether the liposome-entrapped precursors of photosensitizers can induce the expression of metalloproteinases (MMPs) in animal tumor cells and in other tissues from tumor-bearing rats and in selected cell lines in vitro. We also checked whether the application of tissue inhibitors of matrix metalloproteinases (TIMPs) has any effect on MMPs in the above-mentioned experimental models, and if they can cause complete inhibition of MMP expression. Immunohistochemical studies revealed that after the PDT, the intensity of expression of MMPs in healthy animals was very low and seen in single cells only. After the PDT in tumor-bearing rats, MMP-3 was expressed in the tumor cells with the highest intensity of staining in the tissues directly adjacent to the tumors, while MMP-2 and -9 were not found. In the control groups, there was no observed expression of MMPs. In vitro studies showed that MMP-3 was expressed in MCF-7 cells after PDT, but MMP-9 was not observed and MMP-2 was only seen in single cases. Our studies confirmed that the application of an MMP-3 inhibitor may block an induction of MMP-3 expression which had previously been initiated by PDT. The preliminary data obtained from cancer patients revealed that new precursors are effective in terms of PDT, and that using MMP inhibitors should be considered as a potential enhancing factor in clinical PDT.

Photodynamic therapy of human colorectal carcinoma cell line

Colorectal cancer is one of the most common cancers in Europe and North America and it is the most common gastrointestinal carcinoma. The population in the Czech Republic has a higher incidence of colorectal carcinoma compared to other countries. Efforts are underway to develop better screening strategies and novel therapies to improve patient survival rates. Despite all efforts, colorectal cancer remains one of the leading causes of death from cancer. Photodynamic therapy (PDT) is an established modality for the treatment of various diseases. The PDT procedure involves the administration of a photosensitizer followed by illumination. The anti-tumor effects result from direct killing of malignant cells, shutting down of the tumor's vasculature, and the promotion of an immune response. In our experiment, we examined the effects of phototherapy with disulfonated hydroxyaluminum phthalocyanine (Al(OH)S2Pc) on the growth of colorectal carcinoma cells, in an effort to offer a new treatment modality for patients with this disease.

Photodynamic therapy: basic principles and potential uses for the veterinary ophthalmologist

Photodynamic therapy (PDT) involves the use of photochemical reactions mediated through the interaction of photosensitizing agents, light and oxygen. PDT, while now commonly used in physician ophthalmology and oncology, is uncommonly used for the veterinary ophthalmic patient. It is an emerging new therapy in veterinary ophthalmology for the treatment of periocular tumors. This article reviews the basic principles of PDT to provide the veterinary ophthalmologic community with a succinct reference for this emerging treatment modality in our field.

The dual face of endogenous alpha-aminoketones: pro-oxidizing metabolic weapons

Amino metabolites with potential prooxidant properties, particularly alpha-aminocarbonyls, are the focus of this review. Among them we emphasize 5-aminolevulinic acid (a heme precursor formed from succinyl-CoA and glycine), aminoacetone (a threonine and glycine metabolite), and hexosamines and hexosimines, formed by Schiff condensation of hexoses with basic amino acid residues of proteins. All these metabolites were shown, in vitro, to undergo enolization and subsequent aerobic oxidation, yielding oxyradicals and highly cyto- and genotoxic alpha-oxoaldehydes. Their metabolic roles in health and disease are examined here and compared in humans and experimental animals, including rats, quail, and octopus. In the past two decades, we have concentrated on two endogenous alpha-aminoketones: (i) 5-aminolevulinic acid (ALA), accumulated in acquired (e.g., lead poisoning) and inborn (e.g., intermittent acute porphyria) porphyric disorders, and (ii) aminoacetone (AA), putatively overproduced in diabetes mellitus and cri-du-chat syndrome. ALA and AA have been implicated as contributing sources of oxyradicals and oxidative stress in these diseases. The end product of ALA oxidation, 4,5-dioxovaleric acid (DOVA), is able to alkylate DNA guanine moieties, promote protein cross-linking, and damage GABAergic receptors of rat brain synaptosome preparations. In turn, methylglyoxal (MG), the end product of AA oxidation, is also highly cytotoxic and able to release iron from ferritin and copper from ceruloplasmin, and to aggregate proteins. This review covers chemical and biochemical aspects of these alpha-aminoketones and their putative roles in the oxidative stress associated with porphyrias, tyrosinosis, diabetes, and cri-du-chat. In addition, we comment briefly on a side prooxidant behaviour of hexosamines, that are known to constitute building blocks of several glycoproteins and to be involved in Schiff base-mediated enzymatic reactions.

A novel ex vivo skin model to study the susceptibility of the dermatophyte Trichophyton rubrum to photodynamic treatment in different growth phases

BACKGROUND

Dermatophytes are fungi that can cause infections of skin, hair and nails because of their ability to feed on keratin. Superficial mycoses are among the most prevalent infectious diseases worldwide. Two important restrictions of current therapeutic options are the recurrence of the infection and prolonged treatment. This is especially true for infections caused by Trichophyton rubrum, a widely distributed dermatophyte. The application of photosensitizers for treatment of fungal infections is, within the field of photodynamic treatment (PDT), relatively new. Recently, we demonstrated that the porphyrins 5,10,15-tris(4-methylpyridinium)-20-phenyl-[21H,23H]-porphine trichloride (Sylsens B) and deuteroporphyrin monomethylester (DP mme) were excellent photosensitizers towards T. rubrum when using red light.

OBJECTIVES AND METHODS

To evaluate the photodynamic effectiveness of the porphyrins in a situation that mimics the clinical situation, we developed an ex vivo model using human stratum corneum. This model offers the possibility of applying PDT at different time points during the germination and subsequent development of T. rubrum microconidia. The model was used for two different incubation media, Dulbecco's modified Eagle medium (DMEM) and distilled water.

RESULTS AND CONCLUSIONS

We demonstrated that the PDT susceptibility of T. rubrum depended on the time of PDT application after spore inoculation. A decrease in susceptibility was observed with increasing time of PDT application for both photosensitizers in DMEM. Changing the incubation medium to distilled water resulted in an increased fungicidal effect for Sylsens B and in a decreased effect for DP mme. We conclude that T. rubrum is susceptible to PDT in a situation that mimics the clinical situation. The fungicidal effect of PDT on fungal spores is of particular importance.

Technology insight: Photodynamic therapy for cholangiocarcinoma

Cholangiocarcinoma is, in most cases, rapidly fatal. Curative resection can only be offered to approximately 10% of patients. Even after seemingly curative resection, recurrence frequently occurs. Adjuvant chemotherapy and/or radiotherapy do not reduce the recurrence rate after resection. In the palliative setting, endoscopic or percutaneous biliary drainage is performed to relieve jaundice; however, poor results have been obtained in patients with tumors involving the intrahepatic bile ducts. Biliary drainage alleviates jaundice, but there is no evidence that it prolongs life. Palliative chemotherapy and/or radiotherapy have not been proven to prolong life and relieve jaundice. Photodynamic therapy (PDT) is a relatively new local, minimally invasive procedure that can be used to treat cholangiocarcinoma. PDT uses the physical properties of light-absorbing molecules, so-called photosensitizers, which accumulate within proliferating cells. Activation of the photosensitizer by a non-thermal laser leads to selective photochemical destruction of tumors. In a randomized trial of patients with nonresectable cholangiocarcinoma, PDT prolonged survival time, improved cholestasis and quality of life considerably, and had a favorable side-effect profile. A second randomized trial confirmed the beneficial effect of PDT. For the time being, PDT is recommended for patients with nonresectable disease. The role of PDT before and after surgical resection needs to be assessed.

Dose Response of Combination Photorejuvenation Using Intense Pulsed Light–Activated Photodynamic Therapy and Radiofrequency Energy

OBJECTIVE

To report the results of a dose-response study using a novel photorejuvenation regimen consisting of intense pulsed light-activated photodynamic therapy and radiofrequency energy in patients with Fitzpatrick skin types I through III.

METHODS

A combination intense pulsed light and radiofrequency device (Syneron Medical Ltd, Yokneam, Israel) was used in combination with the topical photosensitizer aminolevulinic acid (ALA) (Levulan Kerastick; DUSA Pharmaceuticals Inc, Wilmington, Mass). Duplicate titration trials were performed on the dorsal forearm skin of 3 patients with Fitzpatrick skin types I through III. Multiple treatments, with varying times of application of ALA (30 minutes and 1, 2, and 3 hours) and intense pulsed light fluence (24-30 J/cm(2)), were completed to determine a minimal erythema dose and a maximal tolerated dose based on epidermal reaction (erythema and crusting) and patient discomfort. Radiofrequency energy levels were constant in all treatment groups.

RESULTS

The ALA application time of 1 to 2 hours for all skin types and fluence levels of 26 to 28 and 24 to 26 J/cm(2) for Fitzpatrick skin types I/II and III, respectively, were determined to be the minimal erythema dose. The ALA application times of 2 to 3 hours and fluence levels of 28 to 30 and 26 to 28 J/cm(2) for skin types I/II and III, respectively, were determined to be the maximal tolerated dose and resulted in severe erythema and crusting. The presence of severe erythema and discomfort precluded longer ALA exposure and higher fluence levels. No epithelial breakdown was observed at any treatment levels.

CONCLUSION

The dose-response results defining the minimal erythema dose and the maximal tolerated dose of intense pulsed light-activated photodynamic therapy and radiofrequency energy have led to the development of 2 photorejuvenation protocols based on skin type and severity of photodamage.

The use of dyes in modern biomedicine

The discovery of the aniline dyes in the 19th century and contemporary investigation of their use as biological stains by scientists such as Koch and Ehrlich led to the idea of selectivity and formed the basis of modern chemotherapy; several of these dyes remain in pharmacopoeias. While the development of therapeutics has tended to avoid colored compounds due to unwanted coloration, the modern application of photosensitizing dyes, both in the fields of cancer therapy and anti-infection, depends on this phenomenon. In addition, the fluorescence of some anticancer photosensitizers allows their use as tumor localizing agents, which is particularly useful in precancerous conditions. It is also fitting that dyes employed in Ehrlich's original studies, such as the phenothiazinium dye, methylene blue, are now in clinical use for disinfecting donated blood products.