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Photodynamic Therapy of Psoriasis Using Photosensitizers of Vegetable Origin.
Bruschi, ML, da Silva, JB, Rosseto, HC
Current pharmaceutical design. 2019;(20):2279-2291
Abstract
Psoriasis is an immune-mediated, chronic and recurrent inflammatory skin disease, prevalent worldwide, and represents an important burden in life quality of patients. The most common clinical variant is termed as psoriasis vulgaris or plaque psoriasis, which with an individualized and carefully monitored therapy can decrease the patients' morbidity and improving their life quality. The aim is to achieve disease control, minimize the adverse drug effects, and tailor the treatment to individual patient factors. Photodynamic therapy (PDT) is based on local or systemic administration of a non-toxic photosensitizer followed by irradiation with a particular wavelength to generate reactive oxygen species (ROS), mainly highly cytotoxic singlet oxygen (1O2). The generation of these species results in the attack to substrates involved in biological cycles causing necrosis and apoptosis of affected tissues. Photosensitizers are found in natural products and also obtained by partial syntheses from abundant natural starting compounds. They can be isolated at low cost and in large amounts from plants or algae. Therefore, this manuscript reviews the use of molecules from vegetal sources as photosensitizer agents for the PDT of psoriasis. Psoriasis pathogenesis, management and treatment were reviewed. PDT principles, fundamentals and utilization for the treatment of psoriasis were also discussed. Photosensitizers for PDT of psoriasis are also reviewed focusing on those from vegetal sources. Despite the PDT is utilized for the treatment of psoriasis, very little amount of photosensitizers from plant sources are utilized, such as chlorophyll derivatives and hypericin; however, other natural photosensitizers such as curcumin, could also be investigated. They could constitute a very important, safe and cheap alternative for the successful photodynamic treatment of psoriasis.
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2.
Corneal crosslinking: Current protocols and clinical approach.
Beckman, KA, Gupta, PK, Farid, M, Berdahl, JP, Yeu, E, Ayres, B, Chan, CC, Gomes, JAP, Holland, EJ, Kim, T, et al
Journal of cataract and refractive surgery. 2019;(11):1670-1679
Abstract
Members of the ASCRS Cornea Clinical Committee performed a review of the current literature on the corneal crosslinking (CXL) procedure for treating corneal ectasia. The members explored the data on the techniques currently in use and under investigation, including their advantages, safety profiles, risks, and cost analyses, compared with data on corneal transplantation. They concluded that CXL limits the progression of keratoconus, thus reducing the need for transplantation. They also found that compared with permitting the disease to progress naturally, CXL techniques carry significant and long-term cost and safety benefits, primarily by reducing the need for corneal transplantation. Studies of various CXL techniques (eg, epithelium-on treatment, changes in ultraviolet light parameters, riboflavin composition) continue with the ultimate goal of improving the procedure's safety and efficacy.
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3.
Present and future perspectives of photodynamic therapy for cutaneous squamous cell carcinoma.
Keyal, U, Bhatta, AK, Zhang, G, Wang, XL
Journal of the American Academy of Dermatology. 2019;(3):765-773
Abstract
Cutaneous squamous cell carcinoma (SCC) is the second most common skin cancer. Surgery remains the main stay of treatment, but some patients are not eligible for surgery and, more importantly, lesions at critical sites need nonsurgical approaches for tissue preservation. In this context, photodynamic therapy (PDT) has been extensively studied as noninvasive or minimally invasive treatment, and studies have shown promising results in terms of safety, efficacy, and cosmetic outcome. Also, studies have proposed different mechanism for its efficacy. However, human studies demonstrating its efficacy are limited in terms of sample size and tumor depth of invasion. Good results are mainly seen in case reports of microinvasive SCC, which is defined as SCC limited to papillary dermis. This inadequacy is due to inadequate penetration of topically applied photosensitizers through keratinized tumor surfaces. To overcome these hurdles, pretreatment with lasers or microneedles and encapsulation of photosensitizers into nanoparticles have been tried. Hence, the present article will discuss studies that have demonstrated the efficacy and safety of PDT for cutaneous SCC, studies that have postulated the mechanism of action of PDT, agents that have been used as PDT enhancers, and finally, the recent use of adjuvant therapy in combination with PDT.
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4.
Role of photodynamic therapy in the treatment of esophageal cancer.
Wu, H, Minamide, T, Yano, T
Digestive endoscopy : official journal of the Japan Gastroenterological Endoscopy Society. 2019;(5):508-516
Abstract
Photodynamic therapy (PDT), a treatment of choice for cancer, induces a photochemical reaction, thereby eradicating tumor cells. This is achieved through the administration of a photosensitizer drug, which is activated with a laser after localization to the tumor mass, and is an approved curative endoscopic ablative treatment for superficial esophageal squamous cell carcinoma (ESCC) in Japan. PDT has been approved for dysplastic Barrett's esophagus and as a palliative treatment for patients with symptomatic obstructive esophageal cancer in US. However, its adverse events and complicated procedure and the development of alternative endoscopic procedures such as endoscopic submucosal dissection, radiofrequency ablation and cryotherapy, have largely limited the practice of PDT in esophageal cancer worldwide. Recently, owing to the invention of second-generation PDT using talaporfin sodium and diode laser, PDT can be performed with less phototoxicity and therefore has regained popularity in the treatment of ESCC. As a salvage treatment for patients with local failure after chemoradiotherapy (CRT), PDT has shown promising complete response with less phototoxicity and shorter sun shade period. In addition, the efficacy and safety of PDT in patients with local failure of ESCC after CRT were shown in several clinical trials. The direction of the study interest of the next-generation PDT is the safety and potential expansion of the indications for its application in the future. This review covers the PDT for the treatment of ESCC and dysplastic Barrett's esophagus, with special focus on the role of PDT in practice for esophageal cancer.
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Medical Applications of Rose Bengal- and Riboflavin-Photosensitized Protein Crosslinking.
Redmond, RW, Kochevar, IE
Photochemistry and photobiology. 2019;(5):1097-1115
Abstract
This review summarizes research on many of the potential applications of photosensitized crosslinking of tissue proteins in surgery and current knowledge of the photochemical mechanisms underlying formation of the covalent protein-protein crosslinks involved. Initially developed to close wounds or reattach tissues, protein photocrosslinking has also been demonstrated to stiffen and strengthen tissues, decrease inflammatory responses and facilitate tissue bioengineering. These treatments appear to result largely from crosslinks within and between collagen molecules in tissue that typically form by an oxygen-dependent mechanism. Surgical applications discussed include sealing wounds in skin, cornea and bowel; reattaching severed nerves, blood vessels and tendons; strengthening cornea and vein; reducing capsular contracture after breast implants; and regenerating joint cartilage.
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6.
Corneal Cross-Linking: The Science Beyond the Myths and Misconceptions.
Rubinfeld, RS, Caruso, C, Ostacolo, C
Cornea. 2019;(6):780-790
Abstract
PURPOSE There has been a recent explosion in the variety of techniques used to accomplish corneal cross-linking (CXL) for the treatment of ectatic corneal diseases. To understand the success or failure of various techniques, we review the physicochemical basis of corneal CXL and re-evaluate the current principles and long-standing conventional wisdom in the light of recent, compelling, and sometimes contradictory research. METHODS Two clinicians and a medicinal chemist developed a list of current key topics, controversies, and questions in the field of corneal CXL based on information from current literature, medical conferences, and discussions with international practitioners of CXL. RESULTS Standard corneal CXL with removal of the corneal epithelium is a safe and efficacious procedure for the treatment of corneal ectasias. However, the necessity of epithelium removal is painful for patients, involves risk and requires significant recovery time. Attempts to move to transepithelial corneal CXL have been hindered by the lack of a coherent understanding of the physicochemistry of corneal CXL. Misconceptions about the applicability of the Bunsen-Roscoe law of reciprocity and the Lambert-Beer law in CXL hamper the ability to predict the effect of ultraviolet A energy during CXL. Improved understanding of CXL may also expand the treatment group for corneal ectasia to those with thinner corneas. Finally, it is essential to understand the role of oxygen in successful CXL. CONCLUSIONS Improved understanding of the complex interactions of riboflavin, ultraviolet A energy and oxygen in corneal CXL may provide a successful route to transepithelial corneal CXL.
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7.
Corneal Cross-Linking for Pediatric Keratcoconus Review.
Perez-Straziota, C, Gaster, RN, Rabinowitz, YS
Cornea. 2018;(6):802-809
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Abstract
PURPOSE To comprehensively review the available published literature for cross-linking in the pediatric population. METHODS Review of the literature published in English in PubMed. RESULTS Two hundred ten publications were considered. One hundred fifteen were considered relevant to this review. CONCLUSIONS Studies of cross-linking in pediatric patients are sparse, with relatively short follow-up times, and mostly on small groups of patients. Treatment with cross-linking halts progression of keratoconus in the pediatric population, and early treatment seems to be cost-effective compared with later penetrating keratoplasty. Long-term effects and regression rates remain unclear, and further studies are needed in this population.
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[Intraperitoneal photodynamic therapy for peritoneal metastasis of epithelial ovarian cancer. Limits and future prospects].
Azaïs, H, Mordon, S, Collinet, P
Gynecologie, obstetrique, fertilite & senologie. 2017;(4):249-256
Abstract
High peritoneal recurrence rate in advanced epithelial ovarian cancer after complete macroscopic cytoreductive surgery and platinum-based chemotherapy, raises the issue of peritoneal microscopic disease management and requires the development of additional locoregional treatment strategies. Photodynamic therapy is an effective treatment already applied in other medical and surgical indications. After administration of a photosensitizer which accumulates in cancer cells, illumination with a light of adequate wavelength may induce photochemical reaction between photosensitizer and tissue oxygen which lead to reactive oxygen species production and cytotoxic phenomenon. Photodynamic therapy's ability to treat superficial lesions disseminated on large area makes it an excellent candidate to insure destruction of microscopic peritoneal metastases in addition to macroscopic cytoreductive surgery in order to decrease peritoneal recurrence rate. Development of intraperitoneal photodynamic therapy has been limited by its poor tolerance related to the lack of specificity of photosensitizers and the location of the metastases in proximity to adjacent intraperitoneal organs. Our aim is to review clinical data concerning intraperitoneal photodynamic therapy and epithelial ovarian cancer to identify the limits of this strategy and to provide solutions which may be applied to solve these barriers and enable safe and effective treatment. Targeted photosensitizers and innovative illumination solutions are mandatory to continue research in this field and to consider the feasibility of clinical trials.
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Accelerated versus conventional corneal crosslinking for refractive instability: an update.
Kymionis, GD, Kontadakis, GA, Hashemi, KK
Current opinion in ophthalmology. 2017;(4):343-347
Abstract
PURPOSE OF REVIEW Corneal crosslinking (CXL) is a relatively new treatment modality offering refractive stability in patients with ectatic disorders. The procedure as initially described (Dresden protocol) is time consuming; accelerated protocols have been lately developed. The purpose of this review is to present the recent findings regarding the comparison of accelerated CXL with the conventional Dresden protocol. RECENT FINDINGS A variety of accelerated protocols are described in the literature. Safety and efficacy of the procedures with regard to stability seem to be equivalent in initial studies but indirect measures of efficacy, such as demarcation line depth and laboratory measurements, do not always confirm equivalence of accelerated protocols in comparison to conventional one. Modified accelerated protocols must be developed in order to overcome this. SUMMARY Accelerated CXL protocols seem to be a valid alternative to the conventional protocol; however, more comparative long term studies are needed to confirm the validity and to elucidate which accelerated protocol is ideal in each case.
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Efficacy of Corneal Collagen Cross-Linking for the Treatment of Keratoconus: A Systematic Review and Meta-Analysis.
Meiri, Z, Keren, S, Rosenblatt, A, Sarig, T, Shenhav, L, Varssano, D
Cornea. 2016;(3):417-28
Abstract
PURPOSE To examine the efficacy of corneal collagen cross-linking (CXL) for the treatment of keratoconus (KCN). METHODS A systemic literature review and meta-analysis of ocular functional and structural parameters of patients with KCN undergoing cross-linking procedures were performed using PubMed and the web of science. A literature search was performed for relevant peer-reviewed publications on population-based studies. Data were analyzed with R software (Meta library), and heterogeneity was assessed with the Cochran Q and I. A random-effects model was used for high heterogeneity; otherwise a fixed model was used. Sensitivity analysis of particular tested groups was used to explain high heterogeneity. The main outcome measures extracted from the articles were corrected distance visual acuity, uncorrected distance visual acuity, and maximum K. RESULTS An improvement in visual acuity of 1 to 2 Snellen lines was found 3 months or more after undergoing CXL. Changes were more pronounced in uncorrected visual acuity. Some topography parameters were found to be improved (0.6-1 diopters) 12 to 24 months after CXL. The refractive cylinder improved by 0.4 to 0.7 diopters. Endothelial cell density decreased by 225 cells per square millimeter in the first 3 months and thereafter returned to normal. Corneal thickness was reduced by 10 to 20 μm in the year following CXL but not after 24 months. No changes in intraocular pressure were noted. CONCLUSIONS CXL is a safe and effective method for halting the deterioration of KCN, while slightly improving visual function.