Abstract:Photodynamic therapy (PDT) uses non-toxic photosensitizers and harmless visible light in combination with oxygen to produce cytotoxic reactive oxygen species that kill malignant cells by apoptosis and/or necrosis, shut down the tumour microvasculature and stimulate the host immune system. In contrast to surgery, radiotherapy and chemotherapy that are mostly immunosuppressive, PDT causes acute inflammation, expression of heat-shock proteins, invasion and infiltration of the tumour by leukocytes, and might incre… Show more
“…The action mechanism of PDT is based on the photo-activation of specific compounds, called photosensitizers, which trigger cell death and modulate the immune response [10,11]. As an anti-microbial therapy, PDT stands as a procedure that does not induce microbial resistance [11].…”
Background: Diabetic patients are susceptible to developing foot ulcers with serious complications such as osteomyelitis and amputations. Treatment approaches are still empirical and the benefit of usual procedures such as surgical debridement has not been properly evaluated. Photodynamic Therapy (PDT) is a non-invasive and highly efficient method for the treatment of the diabetic foot, being able to eradicate the infection and to stimulate healing, decreasing considerably the amputation risk. In the day-to-day practice of our service, we have been faced with the question whether debridement is necessary before PDT. In here, we designed a study to answer that question.
Methods: Patients were divided in two groups: In one of the groups (n = 17), debridement was performed before PDT and in the other (n = 40) only PDT treatment was performed. PDT sessions were performed once a week in all patients until healing was achieved, as indicated by visual inspection as well as by radiographic and laboratory exams. At the start of the study, the two groups had no statistical differences concerning their clinical features: average age, gender, insulin use, diabetes mellitus onset time and previous amputations.
Results: PDT was effective in the treatment of 100% of the patients showing no relapses after one year of follow up. The group submitted to PDT without previous debridement had a statistically significant (p = 0.036, Mann-Whitney) shorter cure time (29 days, ~27%).
Conclusion: Our data indicates that debridement is not necessary in the treatment of diabetic foot in patients that have enough peripheral arterial perfusion. In addition, we reproduced previous studies confirming that PDT is an efficient, safe, simple and affordable treatment method for the diabetic foot.
“…The action mechanism of PDT is based on the photo-activation of specific compounds, called photosensitizers, which trigger cell death and modulate the immune response [10,11]. As an anti-microbial therapy, PDT stands as a procedure that does not induce microbial resistance [11].…”
Background: Diabetic patients are susceptible to developing foot ulcers with serious complications such as osteomyelitis and amputations. Treatment approaches are still empirical and the benefit of usual procedures such as surgical debridement has not been properly evaluated. Photodynamic Therapy (PDT) is a non-invasive and highly efficient method for the treatment of the diabetic foot, being able to eradicate the infection and to stimulate healing, decreasing considerably the amputation risk. In the day-to-day practice of our service, we have been faced with the question whether debridement is necessary before PDT. In here, we designed a study to answer that question.
Methods: Patients were divided in two groups: In one of the groups (n = 17), debridement was performed before PDT and in the other (n = 40) only PDT treatment was performed. PDT sessions were performed once a week in all patients until healing was achieved, as indicated by visual inspection as well as by radiographic and laboratory exams. At the start of the study, the two groups had no statistical differences concerning their clinical features: average age, gender, insulin use, diabetes mellitus onset time and previous amputations.
Results: PDT was effective in the treatment of 100% of the patients showing no relapses after one year of follow up. The group submitted to PDT without previous debridement had a statistically significant (p = 0.036, Mann-Whitney) shorter cure time (29 days, ~27%).
Conclusion: Our data indicates that debridement is not necessary in the treatment of diabetic foot in patients that have enough peripheral arterial perfusion. In addition, we reproduced previous studies confirming that PDT is an efficient, safe, simple and affordable treatment method for the diabetic foot.
“…Photodynamic therapy (PDT) utilizes a tumor-localizing photosensitizer and visible light to produce reactive oxygen species (ROS) (Dolmans et al, 2003). PDT efficacy relies on a combination of direct ROS-mediated cytotoxic effects, vascular damage and induction of inflammatory responses (Dolmans et al, 2003;Castano et al, 2006), indicating a critical role for the molecular interplay between cancer cells and the surrounding tumor environment in therapeutic outcome.…”
Photodynamic therapy (PDT) is an anticancer approach utilizing a light-absorbing molecule and visible light irradiation to generate, in the presence of O 2 , cytotoxic reactive oxygen species, which cause tumor ablation. Given that the photosensitizer hypericin is under consideration for PDT treatment of bladder cancer we used oligonucleotide microarrays in the T24 bladder cancer cell line to identify differentially expressed genes with therapeutic potential. This study reveals that the expression of several genes involved in various metabolic processes, stress-induced cell death, autophagy, proliferation, inflammation and carcinogenesis is strongly affected by PDT and pinpoints the coordinated induction of a cluster of genes involved in the unfolded protein response pathway after endoplasmic reticulum stress and in antioxidant response. Analysis of PDT-treated cells after p38 MAPK inhibition or silencing unraveled that the induction of an important subset of differentially expressed genes regulating growth and invasion, as well as adaptive mechanisms against oxidative stress, is governed by this stress-activated kinase. Moreover, p38 MAPK inhibition blocked autonomous regrowth and migration of cancer cells escaping PDT-induced cell death. This analysis identifies new molecular effectors of the cancer cell response to PDT opening attractive avenues to improve the therapeutic efficacy of hypericin-based PDT of bladder cancer.
“…In addition to further development of more potent photosensitising drugs and their selective tumour localization, a promising approach appears in exploiting the PDT-associated host response. Tumour PDT elicits a strong host response orchestrated by the innate immune system that culminates in the development of adaptive immunity against the treated lesion, and renders an important contribution to the therapy outcome (Henderson and Gollnick, 2003;Castano et al, 2006;Korbelik, 2006). It has recently become evident that complement system is engaged at multiple levels in the execution of this host response, including (i) initial recognition of endogenous danger signals generated by tumour-localised insult inflicted by PDT, (ii) incitement and propagation of the elicited inflammatory response, (iii) efferocytosis (dead cell removal), and (iv) tumour antigen presentation and promotion of adaptive immune response recognising the PDT-treated tumour as its target Korbelik and Sun, 2006).…”
Host response elicited by photodynamic therapy (PDT) of cancerous lesions is a critical contributor to the clinical outcome, and complement system has emerged as its important element. Amplification of complement action was shown to improve tumour PDT response. In search of a clinically relevant complement activator for use as a PDT adjuvant, this study focused on g-inulin and examined its effects on PDT response of mouse tumours. Intralesional g-inulin (0.1 mg mouse À1 ) delivered immediately after PDT rivaled zymosan (potent classical complement activator) in delaying the recurrence of B16BL6 melanomas. This effect of g-inulin was further enhanced by IFN-g pretreatment. Tumour C3 protein levels, already elevated after individual PDT or g-inulin treatments, increased much higher after their combination. With fibrosarcomas MCA205 and FsaR, adjuvant g-inulin proved highly effective in reducing recurrence rates following PDT using four different photosensitisers (BPD, ce6, Photofrin, and mTHPC). At 3 days after PDT plus g-inulin treatment, over 50% of cells found at the tumour site were CTLs engaged in killing specific targets via perforingranzyme pathway. This study demonstrates that g-inulin is highly effective PDT adjuvant and suggests that by amplifying the activation of complement system, this agent potentiates the development of CTL-mediated immunity against PDT-treated tumours.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.