Efficacy of localized phototherapy and photodynamic therapy for psoriasis: a systematic review and meta-analysis

An overview of Skp2: a promising new therapeutic target of psoriasis

INTRODUCTION

Psoriasis is a chronic immune-mediated disorder affecting over 2-3% of the population worldwide, significantly impacting quality of life. Despite the availability of various therapeutic interventions, concerns persist regarding lesion recurrence and potential alterations in immune surveillance promoting cancer progression. Recent advancements in understanding cellular and molecular pathways have unveiled key factors in psoriasis etiology, including IL-17, 22, 23, TNF-α, PDE-4, JAK-STAT inhibitors, and AhR agonists. This work explores the potential of S-phase kinase-associated protein 2 (Skp2) as a therapeutic target in psoriasis.

AREA COVERED

This review covers the current understanding of psoriasis pathophysiology, including immune dysregulation, and the role of keratinocytes and ubiquitin. It also delves into Skp2 role in cell cycle regulation, and its correlation with angiogenesis and ubiquitin in psoriasis. The evolving therapeutic approaches targeting Skp2, including small molecule inhibitors, are also discussed.

EXPERT OPINION

Targeting Skp2 holds promise for developing novel therapeutic approaches for psoriasis. By modulating Skp2 activity or expression, it may be possible to intervene in inflammatory and proliferative processes underlying the disease. Further research into Skp2 inhibitors and their efficacy in preclinical and clinical settings is warranted to harness the full potential of Skp2 as a therapeutic target in psoriasis management.

Add-on effects of Chinese herbal medicine external application (FZHFZY) to topical urea for mild-to-moderate psoriasis vulgaris: Protocol for a double-blinded randomized controlled pilot trial embedded with a qualitative study

Psoriasis vulgaris is a chronic dermatological disease with a high global prevalence. It significantly reduces patients' quality of life and is associated with a substantial economic burden. Conventional therapies for mild-to-moderate psoriasis are often associated with insufficient long-term symptomatic relief and side effects. Chinese herbal medicine (CHM) is commonly used for psoriasis management. A CHM formula, namely Fu zheng he fu zhi yang (FZHFZY), has shown promising treatment effects in clinical practice when used as a bath therapy. However, its efficacy and safety has not been evaluated by a rigorous randomized controlled trial (RCT). Therefore, we designed a double-blinded pilot RCT embedded with a qualitative study on CHM formula FZHFZY plus topical urea for mild-to-moderate psoriasis vulgaris to advance the evidence development and practice of CHM external application for psoriasis. This will be a mixed-method design consisting of a pilot RCT and a qualitative study. The pilot RCT is a two-arm, parallel, placebo-controlled, double-blinded trial. Sixty eligible participants will be randomized at a 1:1 ratio to receive eight weeks' treatment of either FZHFZY plus 10% urea cream, or placebo plus 10% urea cream, with 12-week follow-up visits after the treatment phase. The CHM or placebo will be administered externally as a bath therapy. Outcome measures include trial feasibility, efficacy and safety. The primary efficacy outcome will be Psoriasis Area Severity Index (PASI). Secondary efficacy outcomes include Physician Global Assessment, PASI-75, PASI-50, Body Surface Area, Dermatology Life Quality Index, Skindex-16, itch visual analogue scale and relapse. The qualitative study will be conducted to collect participants' feedback on CHM external application and their experience with the pilot RCT. This study will advance the evidence-based clinical practice of using CHM for psoriasis vulgaris and then to support translation of findings into clinical practice in the future. Trial registration number: ChiCTR2200064092.

Laser and Lights in Psoriasis

Psoriasis is a chronic inflammatory skin condition affecting millions of individuals worldwide. Over the years, various treatment modalities have been explored to alleviate the symptoms and improve the quality of life for patients with psoriasis. Among these treatment options, lasers and lights have emerged as promising non-invasive approaches with significant efficacy. This review aims to provide an overview of the current understanding and clinical applications of lasers and lights in the management of psoriasis. We have discussed the mechanisms of action behind different laser and light therapies and their impact on psoriatic plaques. Additionally, we discuss the various types of lasers and lights utilized, including excimer lasers, pulsed dye lasers, and narrowband ultraviolet B (NB-UVB) phototherapy, highlighting their unique properties and clinical outcomes. Moreover, we have addressed important considerations related to patient selection, treatment protocols, and potential side effects associated with lasers and lights. We emphasize the need for proper evaluation, monitoring, and customization of treatment plans to ensure optimal outcomes and minimize adverse events.

An Overview of Contemporary and Future Therapeutic Strategies for Scalp Psoriasis

Scalp psoriasis is a common manifestation of psoriasis that significantly impacts a patient's quality of life. About 80% of cases of psoriasis involve the scalp, making it the most frequently affected area of the body. The treatment of scalp psoriasis is particularly crucial because of its hard-to-treat nature and substantial adverse impacts on overall well-being. Along with the physical symptoms of discomfort and itching, psoriasis, especially when it affects the scalp, can cause severe psychological damage. Treating scalp psoriasis can be challenging due to its location and associated symptoms, such as scaling and pruritus, which is why various drugs have become widely used for refractory cases. Topical treatments like corticosteroids and vitamin D analogs manage scalp psoriasis by reducing inflammation and regulating skin cell growth. Tar-based shampoos, salicylic acid solutions, and moisturizers control scaling. Phototherapy with UVB light reduces inflammation. Severe cases may require systemic medications such as oral retinoids and immunosuppressants. While various therapies are accessible for scalp psoriasis, concerns arise due to their limited advantages and the absence of controlled studies assessing their effectiveness. Considering these challenges, there is a clear demand for innovative approaches to address this condition effectively. Recent advancements in topical therapies, phototherapy, systemic agents, and complementary therapies have shown promising results in managing scalp psoriasis. Also, the advent of biologics, specifically anti-IL-17 and anti-IL-23 drugs for scalp psoriasis, has seen significant improvements. The review highlights the lack of well-tolerated and effective treatments for scalp psoriasis and underscores the importance of further research in this area. The objective of this review is to clarify the different treatment options currently available or being investigated in clinical trials for managing scalp psoriasis.

Assessment of efficacy and safety of UV-based therapy for psoriasis: a network meta-analysis of randomized controlled trials

BACKGROUND

Previous studies have proven that ultraviolet (UV)-based phototherapy, including UVB or psoralen UVA (PUVA), and their combination therapies, is effective for psoriasis treatment.

OBJECTIVE

To compare the clinical efficacy and adverse events (AEs) of different UV-based phototherapy in psoriasis.

METHODS

PubMed, Cochrane Library, Scopus and Embase were systematically searched. A random-effect model network meta-analysis with frequentist framework was performed, and results were reported as risk ratios (RRs) with 95% CI. The main variable for assessing effectiveness and safety are PASI 75 response and withdrawal due to AEs. Ranking effects were calculated by surface under the cumulative ranking analysis (SUCRA).

RESULTS

Thirty-two studies involving a total of 2120 psoriasis patients were included in this network meta-analysis. Overall, no significant difference was reported with respect to withdrawal due to AEs or incidence of erythema. The relatively safest strategy was combined adjuvant therapy with PUVA (cPUVA), especially PUVA combined with calcium/vitamin D derivatives (RR 0.98, 95% CI [0.30-3.17], SUCRA = 80.8%). Both cPUVA (RR 1.39, 95% CI [1.00- 1.94]) and combined adjuvant therapy with UVB (cUVB) (RR 1.27, 95% CI [1.03-1.57]) showed a superior effect than the monotherapy of UVA or UVB, respectively. PUVA combined with vitamin D and its derivatives (PAVD) ranked highest concerning clinical effect and safety (clusterank value = 7393.2).

CONCLUSIONS

The efficacy of all the combination therapy regimens was significantly superior to that of UV monotherapy, without significant differences in tolerability and safety. cUVB and cPUVA, and particularly the combination of UVA with calcium/vitamin D derivatives, was ranked as the overall safest and most effective phototherapy method.

An Update on Photodynamic Therapy of Psoriasis—Current Strategies and Nanotechnology as a Future Perspective

Psoriasis (PS) is an immune-mediated skin disease with substantial negative effects on patient quality of life. Despite significant progress in the development of novel treatment options over the past few decades, a high percentage of patients with psoriasis remain undertreated and require new medications with superior long-term efficacy and safety. One of the most promising treatment options against psoriatic lesions is a form of phototherapy known as photodynamic therapy (PDT), which involves either the systemic or local application of a cell-targeting photosensitizing compound, followed by selective illumination of the lesion with visible light. However, the effectiveness of clinically incorporated photosensitizers in psoriasis treatment is limited, and adverse effects such as pain or burning sensations are frequently reported. In this study, we performed a literature review and attempted to provide a pooled estimate of the efficacy and short-term safety of targeted PDT in the treatment of psoriasis. Despite some encouraging results, PDT remains clinically underutilized. This highlights the need for further studies that will aim to evaluate the efficacy of a wider spectrum of photosensitizers and the potential of nanotechnology in psoriasis treatment.

Light- and laser-based treatments for granuloma annulare: A systematic review

BACKGROUND

Granuloma annulare (GA) is challenging to treat, especially when generalized. A systematic review to support the use of light- and laser-based treatments for GA is lacking.

METHODS

We performed a systematic review by searching Cochrane, MEDLINE, and Embase. Title, abstract, full-text screening, and data extraction were done in duplicate. Quality appraisal was performed using the Joanna Briggs Institute critical appraisal tool for case series.

RESULTS

Thirty-one case series met the inclusion criteria, representing a total of 336 patients. Overall, psoralen ultraviolet light A (PUVA) showed the greatest frequency of cases with complete response (59%, n = 77/131), followed by photodynamic therapy (PDT) (52%, n = 13/25), ultraviolet light B (UVB)/narrowband UVB (nbUVB)/excimer laser (40%, n = 19/47), UVA1 (31%, n = 27/86), and lasers (29%, n = 8/28). Overall across treatment modalities, higher response rates were seen in localized GA compared to generalized GA.

CONCLUSIONS

The body of evidence for light- and laser-based treatment of GA is sparse. Our results suggest that PUVA has a high clearance rate for GA but its use may be limited by concerns of carcinogenesis. Although PDT has the second highest clearance rate, adverse effects, small sample sizes, impractical treatment delivery (especially with generalized disease), and long-term concerns of carcinogenesis may limit its use. Although UVB/nbUVB/excimer laser appeared slightly less effective than other light therapies, we recommend UVB/nbUVB/excimer laser therapy as a first-line treatment for patients with generalized GA given wider availability and a favorable long-term safety profile.

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.

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.

Review of in vivo optical molecular imaging and sensing from x-ray excitation

SIGNIFICANCE

Deep-tissue penetration by x-rays to induce optical responses of specific molecular reporters is a new way to sense and image features of tissue function in vivo. Advances in this field are emerging, as biocompatible probes are invented along with innovations in how to optimally utilize x-ray sources.

AIM

A comprehensive review is provided of the many tools and techniques developed for x-ray-induced optical molecular sensing, covering topics ranging from foundations of x-ray fluorescence imaging and x-ray tomography to the adaptation of these methods for sensing and imaging in vivo.

APPROACH

The ways in which x-rays can interact with molecules and lead to their optical luminescence are reviewed, including temporal methods based on gated acquisition and multipoint scanning for improved lateral or axial resolution.

RESULTS

While some known probes can generate light upon x-ray scintillation, there has been an emergent recognition that excitation of molecular probes by x-ray-induced Cherenkov light is also possible. Emission of Cherenkov radiation requires a threshold energy of x-rays in the high kV or MV range, but has the advantage of being able to excite a broad range of optical molecular probes. In comparison, most scintillating agents are more readily activated by lower keV x-ray energies but are composed of crystalline inorganic constituents, although some organic biocompatible agents have been designed as well. Methods to create high-resolution structured x-ray-optical images are now available, based upon unique scanning approaches and/or a priori knowledge of the scanned x-ray beam geometry. Further improvements in spatial resolution can be achieved by careful system design and algorithm optimization. Current applications of these hybrid x-ray-optical approaches include imaging of tissue oxygenation and pH as well as of certain fluorescent proteins.

CONCLUSIONS

Discovery of x-ray-excited reporters combined with optimized x-ray scan sequences can improve imaging resolution and sensitivity.

Combination of targeted UVB phototherapy and calcipotriene versus targeted UVB alone in psoriasis: systematic review and meta-analysis of randomized controlled trials

Background: Targeted UVB and topical calcipotriene have frequently been used in the treatment of psoriasis, but the joint effect of calcipotriene and targeted UVB has been controversial.Objectives: The purpose of this study was to systematically evaluate whether the efficacy of the combined use of targeted UVB and calcipotriene is superior to the targeted UVB alone.Methods: We performed systematic review and meta-analysis of randomized controlled trials (RCTs) in patients with plaque-type psoriasis through searching the defined key words in the PubMed, EMBase, and Cochrane Central Register databases. Pooled mean difference of the Psoriasis Area and Severity Index (PASI) relative change (%) was estimated using a random effect model. The quality of included studies and publication bias were assessed using the Jadad scale and the Egger's test, respectively.Results: A total of five RCTs including 182 patients were included in the systematic review. The mean difference of the PASI relative change (%) between the combined therapy versus the targeted UVB alone was -22.68 (95%CI: -37.12 to -8.24; p = .002). Publication bias was not supported by the Egger's test (p = .424).Conclusion: Addition of calcipotriene ointment may improve the efficacy of the targeted UVB phototherapy in the treatment of plaque-type psoriasis.

Effectiveness of paint psoralen and ultraviolet-A in alopecia areata – Our experience in the national skin center

Background:

Alopecia areata (AA) is usually a benign cause of patchy hair loss that often resolves within a few weeks to months. Most treatment modalities are ineffective in the treatment of severe AA. The use of paint psoralen and ultraviolet-A (PUVA) in the treatment of patients with severe forms of AA has been reported in the literature.

Aims and Objective:

The aim of this study was to evaluate the effectiveness of paint PUVA therapy in the treatment of AA in Singapore.

Materials and Methods:

We performed a 10-year retrospective analysis of patients who underwent paint PUVA for AA. We evaluated patient demographics and treatment outcomes in the form of percentage change in baseline severity of alopecia tool score and final amount of hair regrowth and relapse rate.

Results:

Ten patients were included in this study. With paint PUVA therapy, significant hair regrowth was seen in six patients. Paint PUVA therapy in our study showed minimal side effects.

Conclusion:

PUVA gives fair response in AA in a reasonable time as per our center's experience in Singapore.

Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy

Psoriasis is a chronic inflammatory disease involving multiple organ systems and affecting approximately 3.2% of the world's population. In this section of the guidelines of care for psoriasis, we will focus the discussion on ultraviolet (UV) light-based therapies, which include narrowband and broadband UVB, UVA in conjunction with photosensitizing agents, targeted UVB treatments such as with an excimer laser, and several other modalities and variations of these core phototherapies, including newer applications of pulsed dye lasers, intense pulse light, and light-emitting electrodes. We will provide an in-depth, evidence-based discussion of efficacy and safety for each treatment modality and provide recommendations and guidance for the use of these therapies alone or in conjunction with other topical and/or systemic psoriasis treatments.

Photoactivated cell-killing involving a low molecular weight, donor-acceptor diphenylacetylene

Drug-like, donor–acceptor diphenylacetylenes cause efficient cell death upon photoactivation and hence have potential phototherapeutic applications.

Photoactivation of photosensitisers can be utilised to elicit the production of ROS, for potential therapeutic applications, including the destruction of diseased tissues and tumours. A novel class of photosensitiser, exemplified by DC324, has been designed possessing a modular, low molecular weight and ‘drug-like’ structure which is bioavailable and can be photoactivated by UV-A/405 nm or corresponding two-photon absorption of near-IR (800 nm) light, resulting in powerful cytotoxic activity, ostensibly through the production of ROS in a cellular environment. A variety of in vitro cellular assays confirmed ROS formation and in vivo cytotoxic activity was exemplified via irradiation and subsequent targeted destruction of specific areas of a zebrafish embryo.

Prescribing Home Narrowband UVB Phototherapy: A Review of Current Approaches

Conventional, full-body phototherapy equipment is costly and therefore patients are usually treated in dermatology centres. Such office-based therapy is often not feasible for those patients who live far away from a phototherapy centre due to lost time and wages, inability to travel because of extensive skin disease, or prohibitive travel costs. Home phototherapy has emerged as a modality that meets the needs of those patients. Our aim was to review available studies on UV sources, treatment protocols, efficacy, and safety of home phototherapy. A literature review was conducted on PubMed using the terms "home" AND "phototherapy" AND ("guide" OR "approach" OR "review" OR "protocol"). From the data extracted, narrowband UVB (311 nm) offers the best balance between safety and efficacy and is recommended for home phototherapy by most authors. Treatment is safe and possible adverse effects are related to overexposure (erythema, blistering). The usual treatment protocol was administering treatments on alternating days, including weekends, with dosing based on the patient's Fitzpatrick skin type. We also provide information on the available home phototherapy systems in Canada and their reimbursement. Home phototherapy is underused in Canada. Narrowband UVB phototherapy sources equipped with a 3-dimensional panel provides a practical and safe option.

Photodynamic therapy in dermatology beyond non-melanoma cancer: An update

Photodynamic therapy (PDT) employs a photosensitizer (PS) and visible light in the presence of oxygen, leading to production of cytotoxic reactive oxygen species, which can damage the cellular organelles and cause cell death. In dermatology, PDT has usually taken the form of topical application of a precursor in the heme biosynthesis pathway, called 5-aminolevulinic acid (or its methyl ester), so that an active PS, protoporphyrin IX accumulates in the skin. As PDT enhances dermal remodeling and resolves chronic inflamation, it has been used to treat cutaneous disorders include actinic keratoses, acne, viral warts, skin rejuvenation, psoriasis, localized scleroderma, some non-melanoma skin cancers and port-wine stains. Efforts are still needed to mitigate the side effects (principally pain) and improve the overall procedure.

Porphyrin-based cationic amphiphilic photosensitisers as potential anticancer, antimicrobial and immunosuppressive agents

Photodynamic therapy (PDT) combines a photosensitiser, light and molecular oxygen to induce oxidative stress that can be used to kill pathogens, cancer cells and other highly proliferative cells. There is a growing number of clinically approved photosensitisers and applications of PDT, whose main advantages include the possibility of selective targeting, localised action and stimulation of the immune responses. Further improvements and broader use of PDT could be accomplished by designing new photosensitisers with increased selectivity and bioavailability. Porphyrin-based photosensitisers with amphiphilic properties, bearing one or more positive charges, are an effective tool in PDT against cancers, microbial infections and, most recently, autoimmune skin disorders. The aim of the review is to present some of the recent examples of the applications and research that employ this specific group of photosensitisers. Furthermore, we will highlight the link between their structural characteristics and PDT efficiency, which will be helpful as guidelines for rational design and evaluation of new PSs.

Phototherapy of Psoriasis, a Chronic Inflammatory Skin Disease

Phototherapy is an effective treatment modality for several skin diseases which has been in use from the era of the Egyptians. Insight into its mode of action has gradually accumulated over the past decades. A crucial biological effect of ultraviolet radiation is the induction of apoptosis in T lymphocytes and in keratinocytes in the epidermis. Via this mechanism inflammation-induced pathological changes characteristic of psoriasis are counteracted.Phototherapy remains the only therapeutic option for certain patient groups where modification of the systemic immune reactions is contraindicated, such as by HIV, internal malignancy or pregnancy. UVB treatment is highly cost-effective, which is important in this age of increasing health care costs.

Activated T cells exhibit increased uptake of silicon phthalocyanine Pc 4 and increased susceptibility to Pc 4-photodynamic therapy-mediated cell death

Photodynamic therapy (PDT) is an emerging treatment for malignant and inflammatory dermal disorders. Photoirradiation of the silicon phthalocyanine (Pc) 4 photosensitizer with red light generates singlet oxygen and other reactive oxygen species to induce cell death. We previously reported that Pc 4-PDT elicited cell death in lymphoid-derived (Jurkat) and epithelial-derived (A431) cell lines in vitro, and furthermore that Jurkat cells were more sensitive than A431 cells to treatment. In this study, we examined the effectiveness of Pc 4-PDT on primary human CD3(+) T cells in vitro. Fluorometric analyses of lysed T cells confirmed the dose-dependent uptake of Pc 4 in non-stimulated and stimulated T cells. Flow cytometric analyses measuring annexin V and propidium iodide (PI) demonstrated a dose-dependent increase of T cell apoptosis (6.6-59.9%) at Pc 4 doses ranging from 0-300 nM. Following T cell stimulation through the T cell receptor using a combination of anti-CD3 and anti-CD28 antibodies, activated T cells exhibited increased susceptibility to Pc 4-PDT-induced apoptosis (10.6-81.2%) as determined by Pc 4 fluorescence in each cell, in both non-stimulated and stimulated T cells, Pc 4 uptake increased with Pc 4 dose up to 300 nM as assessed by flow cytometry. The mean fluorescence intensity (MFI) of Pc 4 uptake measured in stimulated T cells was significantly increased over the uptake of resting T cells at each dose of Pc 4 tested (50, 100, 150 and 300 nM, p < 0.001 between 50 and 150 nM, n = 8). Treg uptake was diminished relative to other T cells. Cutaneous T cell lymphoma (CTCL) T cells appeared to take up somewhat more Pc 4 than normal resting T cells at 100 and 150 nm Pc 4. Confocal imaging revealed that Pc 4 localized in cytoplasmic organelles, with approximately half of the Pc 4 co-localized with mitochondria in T cells. Thus, Pc 4-PDT exerts an enhanced apoptotic effect on activated CD3(+) T cells that may be exploited in targeting T cell-mediated skin diseases, such as cutaneous T cell lymphoma (CTCL) or psoriasis.

Ultraviolet B Phototherapy for Psoriasis: Review of Practical Guidelines

Psoriasis is an inflammatory skin condition that affects approximately 2 % of people worldwide. Topical treatments, systemic treatments, biologic agents, and phototherapy are all treatment options for psoriasis. Ultraviolet (UV) B phototherapy is most appropriate for patients with >10 % affected body surface area who have not responded to topical treatments. This review outlines the use, dosage, safety, and efficacy of narrowband UVB (NB-UVB) and targeted phototherapy. NB-UVB and excimer laser are effective treatment options for psoriasis; they are administered two to three times weekly until clearance followed by maintenance treatment before discontinuation. Long-term data on NB-UVB indicate that it has a good safety profile. NB-UVB is commonly used with adjunctive topical treatments such as emollients, calcipotriene, cortico-steroids, retinoids, and tar. NB-UVB can be used in selected patients with traditional systemic agents such as methotrexate, mycophenolate mofetil, and cyclosporine, although the duration of the combined treatment should be kept to a minimum and patients need to be closely monitored. Acitretin can be safely used with phototherapy, but robust data on the combination use of biologic agents or phosphodiesterase inhibitors with phototherapy are lacking.

Glucose-functionalized amino-OPEs as biocompatible photosensitizers in PDT

Photodynamic therapy (PDT) is a minimally invasive procedure that can provide a selective eradication of neoplastic diseases by the combined effect of a photosensitizer, light and oxygen. New amino oligo(phenylene-ethynylene)s (OPEs), bearing hydrophilic glucoside terminations, have been prepared, characterized and tested as photosensitizers in PDT. The effectiveness of these compounds in combination with UVA light has been checked on two tumor cell lines (HEp-2 and HeLa cells, derived from a larynx carcinoma and a cervical carcinoma, respectively). The compounds triggered a mitotic blockage that led to the cell death, being the effect active up to 3 μm concentration. The photophysical properties of OPEs, such as high quantum yield, stability, singlet oxygen production, biocompatibility, easy cell-internalization and very good response even at low concentration, make them promising photosensitizers in the application of PDT.

Synthesis and Characterization of Chitosan-Coated Near-Infrared (NIR) Layered Double Hydroxide-Indocyanine Green Nanocomposites for Potential Applications in Photodynamic Therapy

We designed a study for photodynamic therapy (PDT) using chitosan coated Mg-Al layered double hydroxide (LDH) nanoparticles as the delivery system. A Food and Drug Administration (FDA) approved near-infrared (NIR) fluorescent dye, indocyanine green (ICG) with photoactive properties was intercalated into amine modified LDH interlayers by ion-exchange. The efficient positively charged polymer (chitosan (CS)) coating was achieved by the cross linkage using surface amine groups modified on the LDH nanoparticle surface with glutaraldehyde as a spacer. The unique hybridization of organic-inorganic nanocomposites rendered more effective and successful photodynamic therapy due to the photosensitizer stabilization in the interlayer of LDH, which prevents the leaching and metabolization of the photosensitizer in the physiological conditions. The results indicated that the polymer coating and the number of polymer coats have a significant impact on the photo-toxicity of the nano-composites. The double layer chitosan coated LDH-NH₂-ICG nanoparticles exhibited enhanced photo therapeutic effect compared with uncoated LDH-NH₂-ICG and single layer chitosan-coated LDH-NH₂-ICG due to the enhanced protection to photosensitizers against photo and thermal degradations. This new class of organic-inorganic hybrid nanocomposites can potentially serve as a platform for future non-invasive cancer diagnosis and therapy.

Ultraviolet radiation signaling through TLR4/MyD88 constrains DNA repair and plays a role in cutaneous immunosuppression

UV radiation (UVR) induces DNA damage, leading to the accumulation of mutations in epidermal keratinocytes and immunosuppression, which contribute to the development of nonmelanoma skin cancer. We reported previously that the TLR4-MyD88 signaling axis is necessary for UV-induced apoptosis. In the dinitrofluorobenzene contact hypersensitivity model, UV-irradiated MyD88-deficient (MyD88(-/-)) C57BL/6 mice had intact ear swelling, exaggerated inflammation, and higher levels of dinitrofluorobenzene-specific IgG2a compared with wild-type (WT) mice. Even with normal UV-induced, dendritic cell migration, DNA damage in the local lymph nodes was less pronounced in MyD88(-/-) mice compared with WT mice. Cultured, UV-irradiated WT APCs showed cleavage (inactivation) of the DNA damage-recognition molecule PARP, whereas PARP persisted in MyD88(-/-) and TLR4(-/-) APCs. Epidermal DNA from in vivo UV-irradiated MyD88(-/-) mice had an increased resolution rate of cyclobutane pyrimidine dimers. Both in vitro treatment of MyD88(-/-) APCs with and intradermal in vivo injections of PARP inhibitor, PJ-34, caused WT-level cyclobutane pyrimidine dimer repair. Lymphoblasts deficient in DNA repair (derived from a xeroderma pigmentosum group A patient) failed to augment DNA repair after MyD88 knockdown after UVR, in contrast to lymphoblasts from a healthy control. These data suggest that interference with the TLR4/MyD88 pathway may be a useful tool in promoting DNA repair and maintaining immune responses following UVR-induced damage.

Role of TRP channels in the induction of heat shock proteins (Hsps) by heating skin

Transient receptor potential (TRP) channels in skin are crucial for achieving temperature sensitivity to maintain internal temperature balance and thermal homeostasis, as well as to protect skin cells from environmental stresses such as infrared (IR) or near-infrared (NIR) radiation via heat shock protein (Hsp) production. However, the mechanisms by which IR and NIR activate TRP channels and produce Hsps intracellularly have been independently reported. In this review, we discuss the relationship between TRP channel activation and Hsp production, and introduce the roles of several skin TRP channels in the regulation of HSP production by IR and NIR exposure.