Attempt of photodynamic therapy on esophageal varices. Lasers Med Sci. 2009;24:167-171. [PMID: 18270762 DOI: 10.1007/s10103-008-0542-6]

Enhanced therapeutic precision using dual drug-loaded nanomaterials for targeted cancer photodynamic therapy

Combination therapy has expanded significantly, including dual drug-loaded nanomaterials in drug delivery systems. Cancer therapy can be developed by targeting cancer cells and lessening the adverse consequences of anticancer drugs, which are just two of the numerous intriguing possibilities in this research field. Dual-drug delivery nanosystems that utilize nanotechnology to combine dual-drug administration may overcome the limitations of free drugs, the properties of nanomaterials, and the combined action of two drugs work together to overcome several drug-resistant systems within cancerous cells. It is essential to design dual-drug delivery nanosystems that use various multidrug-resistant techniques to overcome drug resistance mechanisms and enhance the effectiveness of clinical antitumor therapy. In this study, we discuss the use of photosensitizers in cancer photodynamic therapy, nanomaterials with dual-drug loading for targeted drug delivery, and the function and impact of nanomaterials in cancer photodynamic therapy. Furthermore, an overview of the drug-loaded nanomaterials in vitro and in vivo activity for cancer photodynamic treatment is discussed. The commercial and clinical applications of photosensitizer-loaded nanoparticles in cancer photodynamic therapy are also briefly discussed in the study. A key finding of the study is the importance of nanomaterials and dual drugs as effective drug delivery systems in cancer treatment.

Exploring the application of herbal photosensitizers in antimicrobial photodynamic therapy against Mycobacterium Tuberculosis

Tuberculosis (TB) is one of the leading causes of death in the world, despite being a preventable and curable disease. Irrespective of tremendous advancements in early detection and treatment, this disease still has high mortality rates. This is due to the development of antibiotic resistance, which significantly reduced the efficacy of antibiotics, rendering them useless against this bacterial infection. This, in turn, causes immune system evasion, antibiotic treatment failures, and recurrence of disease in patients. Regarding this, photodynamic inactivation (PDI) may serve as a useful substitute for antibiotic therapy against drug-resistant mycobacteria. This century-old therapy is already being used in cancer treatment, dentistry, and skeletal and cardiovascular diseases, but it is not yet used in tuberculosis treatment. Researchers have previously used PDI to eradicate other members of the genus Mycobacteria in both in vitro and in vivo settings. This suggests PDI can be explored against M. tuberculosis too. The one limitation associated with PDI is the use of chemical photosensitizers, which are fatal to normal tissues and induce side effects. Recent studies suggest herbal photosensitizers are equally potent as chemically synthesized ones. Therefore, herbal photosensitizers could be used to solve the problem because of their less toxicity to healthy tissues and decreased frequency of side effects. This review emphasizes the importance of herbal photosensitizers and their role as anti-tuberculosis drugs in PDI therapy and also presents five potential herbal photosensitizers-curcumin, quercetin, resveratrol, aloe emodin, and phloretin that could be utilized in the clinical development of PDT-mediated tuberculosis therapies.

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

In Vitro Antimicrobial Photodynamic Therapy for Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) Inhibition Using a Green Light Source

Photodynamic therapy (PDT) has been based on using photosensitizers (PS) and applying light of a specific wavelength. When this technique is used for treating infections, it is known as antimicrobial photodynamic therapy (aPDT). Currently, the use of lighting sources for in vitro studies using aPDT is generally applied in multiwell cell culture plates; however, depending on the lighting arrangement, there are usually errors in the application of the technique because the light from a well can affect the neighboring wells or it may be that not all the wells are used in the same experiment. In addition, one must be awarded high irradiance values, which can cause unwanted photothermal problems in the studies. Thus, this manuscript presents an in vitro antimicrobial photodynamic therapy for a Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) inhibition study using an arrangement of thermally isolated and independently illuminated green light source systems for eight tubes in vitro aPDT, determining the effect of the following factors: (i) irradiance level, (ii) exposure time, and (iii) Rose Bengal (RB) concentration (used as a PS), registering the Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) inhibition rates. The results show that in the dark, RB had a poor antimicrobial rate for P. aeruginosa, finding the maximum inhibition (2.7%) at 30 min with an RB concentration of 3 µg/mL. However, by applying light in a correct dosage (time × irradiance) and the adequate RB concentration, the inhibition rate increased by over 37%. In the case of MRSA, there was no significant inhibition with RB in complete darkness and, in contrast, the rate was 100% for those experiments that were irradiated.

Tissue Engineering and Photodynamic Therapy: A New Frontier of Science for Clinical Application -An Up-To-Date Review

Tissue engineering (TE) connects principles of life sciences and engineering to develop biomaterials as alternatives to biological systems and substitutes that can improve and restore tissue function. The principle of TE is the incorporation of cells through a 3D matrix support (scaffold) or using scaffold-free organoid cultures to reproduce the 3D structure. In addition, 3D models developed can be used for different purposes, from studies mimicking healthy tissues and organs as well as to simulate and study different pathologies. Photodynamic therapy (PDT) is a non-invasive therapeutic modality when compared to conventional therapies. Therefore, PDT has great acceptance among patients and proves to be quite efficient due to its selectivity, versatility and therapeutic simplicity. The PDT mechanism consists of the use of three components: a molecule with higher molar extinction coefficient at UV-visible spectra denominated photosensitizer (PS), a monochromatic light source (LASER or LED) and molecular oxygen present in the microenvironment. The association of these components leads to a series of photoreactions and production of ultra-reactive singlet oxygen and reactive oxygen species (ROS). These species in contact with the pathogenic cell, leads to its target death based on necrotic and apoptosis ways. The initial objective of PDT is the production of high concentrations of ROS in order to provoke cellular damage by necrosis or apoptosis. However, recent studies have shown that by decreasing the energy density and consequently reducing the production of ROS, it enabled a specific cell response to photostimulation, tissues and/or organs. Thus, in the present review we highlight the main 3D models involved in TE and PS most used in PDT, as well as the applications, future perspectives and limitations that accompany the techniques aimed at clinical use.

Photodynamic Therapy Review: Principles, Photosensitizers, Applications, and Future Directions

Photodynamic therapy (PDT) is a minimally invasive therapeutic modality that has gained great attention in the past years as a new therapy for cancer treatment. PDT uses photosensitizers that, after being excited by light at a specific wavelength, react with the molecular oxygen to create reactive oxygen species in the target tissue, resulting in cell death. Compared to conventional therapeutic modalities, PDT presents greater selectivity against tumor cells, due to the use of photosensitizers that are preferably localized in tumor lesions, and the precise light irradiation of these lesions. This paper presents a review of the principles, mechanisms, photosensitizers, and current applications of PDT. Moreover, the future path on the research of new photosensitizers with enhanced tumor selectivity, featuring the improvement of PDT effectiveness, has also been addressed. Finally, new applications of PDT have been covered.

Non-Oncologic Applications of Nanomedicine-Based Phototherapy

Phototherapy is widely applied to various human diseases. Nanomedicine-based phototherapy can be classified into photodynamic therapy (PDT) and photothermal therapy (PTT). Activated photosensitizer kills the target cells by generating radicals or reactive oxygen species in PDT while generating heat in PTT. Both PDT and PTT have been employed for treating various diseases, from preclinical to randomized controlled clinical trials. However, there are still hurdles to overcome before entering clinical practice. This review provides an overview of nanomedicine-based phototherapy, especially in non-oncologic diseases. Multiple clinical trials were undertaken to prove the therapeutic efficacy of PDT in dermatologic, ophthalmologic, cardiovascular, and dental diseases. Preclinical studies showed the feasibility of PDT in neurologic, gastrointestinal, respiratory, and musculoskeletal diseases. A few clinical studies of PTT were tried in atherosclerosis and dry eye syndrome. Although most studies have shown promising results, there have been limitations in specificity, targeting efficiency, and tissue penetration using phototherapy. Recently, nanomaterials have shown promising results to overcome these limitations. With advanced technology, nanomedicine-based phototherapy holds great potential for broader clinical practice.

Vascular-targeted photodynamic therapy of gastric antral vascular ectasia (GAVE)

BACKGROUND AND STUDY AIM

Vascular-targeted photodynamic therapy (V-PDT) has been used for several benign vascular diseases. The aim of this pilot study was to demonstrate the potential benefits of VPDT in the treatment of gastric antral vascular ectasia (GAVE).

PATIENTS AND METHODS

Data from patients with GAVE (n=5) who underwent endoscopic V-PDT were analyzed retrospectively. Pre- and post-V-PDT clinical and endoscopic features, hemoglobin levels, and transfusion requirement were compared.

RESULTS

The five GAVE patients received one to four sessions of V-PDT. The hemoglobin levels of all five patients increased steadily following V-PDT. Within 6-48months of follow-up, gastrointestinal bleeding and melena disappeared in all five patients and none of the patients needed a transfusion. Endoscopy examinations showed that the dilated vessels had disappeared without scar formation. No significant side effects or adverse reactions were reported.

CONCLUSION

This preliminary study indicates the good selectivity, safety, and efficacy of V-PDT in the treatment of patients with GAVE. Larger prospective studies are needed to further confirm the feasibility of using V-PDT to treat patients with GAVE.

Photodynamic inactivation of Candida albicans by hematoporphyrin monomethyl ether

AIM

To evaluate the capacity of hematoporphyrin monomethyl ether (HMME) in the presence of light to cause photodynamic inactivation (PDI) of Candida albicans.

MATERIALS & METHODS

HMME photoactivity was evaluated against azole-susceptible and -resistant C. albicans. The mechanisms by which PDI of C. albicans occurred were also investigated.

RESULTS

HMME-mediated PACT caused a dose-dependent inactivation of azole-susceptible and -resistant C. albicans. Incubation with 10 μM HMME and irradiation with 72 J cm(-2) light decreased the viability of C. albicans by 7 log10, induced damage of genomic DNA, led to loss of cellular proteins and damaged the cell wall, membrane and intracellular targets.

CONCLUSION

Candida albicans can be effectively inactivated by HMME in the presence of light, and HMME-mediated PACT shows its potential as an antifungal treatment.

Antiviral therapy delays esophageal variceal bleeding in hepatitis B virus-related cirrhosis

AIM: To investigate the effect of antiviral therapy with nucleoside analogs in hepatitis B virus (HBV)-related cirrhosis and esophageal varices.

METHODS: Eligible patients with HBV-related cirrhosis and esophageal varices who consulted two tertiary hospitals in Beijing, China, the Chinese Second Artillery General Hospital and Chinese PLA General Hospital, were enrolled in the study from January 2005 to December 2009. Of 117 patients, 79 received treatment with different nucleoside analogs and 38 served as controls. Bleeding rate, change in variceal grade and non-bleeding duration were analyzed. Multivariate Cox proportional hazard regression was used to identify factors related to esophageal variceal bleeding.

RESULTS: The bleeding rate was decreased in the antiviral group compared to the control group (29.1% vs 65.8%, P < 0.001). Antiviral therapy was an independent factor related to esophageal bleeding in multivariate analysis (HR = 11.3, P < 0.001). The mean increase in variceal grade per year was lower in the antiviral group (1.0 ± 1.3 vs 1.7 ± 1.2, P = 0.003). Non-bleeding duration in the antiviral group was prolonged in the Kaplan-Meier model. Viral load rebound was observed in 3 cases in the lamivudine group and in 1 case in the adefovir group, all of whom experienced bleeding. Entecavir and adefovir resulted in lower bleeding rates (17.2% and 28.6%, respectively) than the control (P < 0.001 and P = 0.006, respectively), whereas lamivudine (53.3%) did not (P = 0.531).

CONCLUSION: Antiviral therapy delays the progression of esophageal varices and reduces bleeding risk in HBV-related cirrhosis, however, high-resistance agents tend to be ineffective for long-term treatment.

Vascular targeted photodynamic therapy for bleeding gastrointestinal mucosal vascular lesions: a preliminary study

BACKGROUND

Vascular-targeted photodynamic therapy (V-PDT) has shown good selectivity and efficacy in the treatment of certain types of vascular disease, including port wine stains, age-related macular degeneration, and esophageal varices. This study was conducted to test the efficacy and safety of V-PDT in the treatment of gastrointestinal (GI) bleeding caused by the abnormal dilatation of capillaries.

METHODS

Patients with bleeding GI mucosal vascular lesions treated with V-PDT were included in this retrospective study. The efficiency of V-PDT was analyzed by comparing the documented endoscopy results, hemoglobin levels, and transfusion requirements before and at 6 months after the last V-PDT. Side effects during and after V-PDT and follow-up results were also analyzed.

RESULTS

Seven patients with bleeding GI mucosal vascular lesions were treated with V-PDT. After 1-4 V-PDT sessions, all patients no longer needed transfusions to maintain a stable hemoglobin level during the follow-up period of 6 months. The mean hemoglobin level of the seven patients improved from 6.21±1.48 g/dl to 11.66±1.21 g/dl (p<0.001), and the GI bleeding and melena of all the patients disappeared. No perforations, strictures, scars, or episodes of photosensitization occurred in the seven patients, and there were no recurrences of GI bleeding during the 1-21 months of further follow-up.

CONCLUSIONS

This preliminary study indicated that V-PDT is a highly selective, safe, well-tolerated, and effective treatment modality for bleeding GI mucosal vascular lesions. However, prospective studies with larger sample sizes are needed to confirm this finding.