Molecular changes following topical photodynamic therapy using methyl aminolaevulinate in mouse skin

Skin wound healing in diabetic rat model using low-dose photodynamic therapy

Chronic wound is one of the major challenges in medicine and imposes a heavy financial burden on the healthcare of different countries. Diabetic foot ulcers as one of the important examples for chronic wounds can lead to lower limb amputation, disability, and death in diabetics. In this regard, novel technology with low side effects got attention in recent years. Low-dose photodynamic therapy (LDPDT) is one of the noninvasive techniques that can be considered for wound healing in diabetic wounds. In this experiment, we aim to study the effect of LDPDT on diabetic rats' wound healing and compare it to healthy rats. In this in vitro experimental study, 32 male rats were used. Rats in both normal and diabetic (streptozotocin injection) groups after being wounded (two wounds [0.8 × 0.8 cm]) on the back of each rat were randomly divided into four groups, including the control group (without treatment), radiation-only (660 nm-1 J/cm2) group, 5-ALA-only (1 µg/mL) group, and LDPDT-recipient group. The procedure has been done for 2 days, and at the end of Days 3, 7, 14, and 21, the wound sample was sent to the histopathology laboratory, and the wound size and tissue indices in these groups were evaluated by histology and microscopy techniques. The impact of low concentrations of 5-ALA and low irradiation energy density in both normal and diabetic rats were positive, which accelerated the wound-healing process as seen in the histology study. In diabetic rats treated with only radiation and LDPDT, the process of epithelial regeneration, collagen production, reduction of mast cells, and production of follicles was more as compared to the normal group. The results suggest that LDPDT can have a positive impact on the diabetic rat model wound healing.

The Role of Physical Therapies in Wound Healing and Assisted Scarring

Wound healing (WH) is a complex multistep process in which a failure could lead to a chronic wound (CW). CW is a major health problem and includes leg venous ulcers, diabetic foot ulcers, and pressure ulcers. CW is difficult to treat and affects vulnerable and pluripathological patients. On the other hand, excessive scarring leads to keloids and hypertrophic scars causing disfiguration and sometimes itchiness and pain. Treatment of WH includes the cleaning and careful handling of injured tissue, early treatment and prevention of infection, and promotion of healing. Treatment of underlying conditions and the use of special dressings promote healing. The patient at risk and risk areas should avoid injury as much as possible. This review aims to summarize the role of physical therapies as complementary treatments in WH and scarring. The article proposes a translational view, opening the opportunity to develop these therapies in an optimal way in clinical management, as many of them are emerging. The role of laser, photobiomodulation, photodynamic therapy, electrical stimulation, ultrasound therapy, and others are highlighted in a practical and comprehensive approach.

The photosensitizer-based therapies enhance the repairing of skin wounds

Wound repair remains a clinical challenge and bacterial infection is a common complication that may significantly delay healing. Therefore, proper and effective wound management is essential. The photosensitizer-based therapies mainly stimulate the photosensitizer to generate reactive oxygen species through appropriate excitation source irradiation, thereby killing pathogenic microorganisms. Moreover, they initiate local immune responses by inducing the recruitment of immune cells as well as the production of proinflammatory cytokines. In addition, these therapies can stimulate the proliferation, migration and differentiation of skin resident cells, and improve the deposition of extracellular matrix; subsequently, they promote the re-epithelialization, angiogenesis, and tissue remodeling. Studies in multiple animal models and human skin wounds have proved that the superior sterilization property and biological effects of photosensitizer-based therapies during different stages of wound repair. In this review, we summarize the recent advances in photosensitizer-based therapies for enhancing tissue regeneration, and suggest more effective therapeutics for patients with skin wounds.

Effects of methylene blue-mediated photodynamic therapy on a mouse model of squamous cell carcinoma and normal skin

BACKGROUND

Photodynamic therapy is used to treat a variety of cancers and skin diseases by inducing apoptosis, necrosis, immune system activation, and/or vascular damage. Here, we describe the effects of a single photodynamic therapy session using methylene blue on a mouse model of squamous cell carcinoma and normal skin.

METHODS

The photodynamic therapy protocol comprised application of a 1% methylene blue solution, followed by irradiation with a diode laser for 15 min at 74 mW/cm², for a total dose of 100 J/cm². Morphological changes, cell proliferation, apoptosis, collagen quantity, immune system activity, and blood vessel number were analyzed 24 h and 15 days after photodynamic therapy.

RESULTS

In the squamous cell carcinoma group, photodynamic therapy reduced tumor size and cell proliferation and raised cytokine levels. In normal skin, it decreased cell proliferation and collagen quantity and increased apoptosis and blood vessel numbers.

CONCLUSIONS

The effects of photodynamic therapy were greater on normal skin than squamous cell carcinoma tissues. The reduced epithelial thickness and keratinization of the former are factors that contribute to the efficacy of this treatment. Adjustments to the treatment protocol are necessary to potentiate the effects for squamous cell carcinoma therapy.

Photodynamic therapy corrects abnormal cancer-associated gene expression observed in actinic keratosis lesions and induces a remodeling effect in photodamaged skin

BACKGROUND

Actinic keratoses (AK) are proliferations of neoplastic keratinocytes in the epidermis resulting from cumulative exposure to ultraviolet radiation (UVR), which are liable to transform into squamous cell carcinoma (SCC). Organ Transplant Recipients (OTR) have an increased risk of developing SCC as a consequence of long-term immunosuppressive therapy. The aim of this study was to determine the molecular signature of AKs from OTR prior to treatment with methyl aminolevulinate-photodynamic therapy (MAL-PDT), and to assess what impact the treatment has on promoting remodeling of the photo-damaged skin.

METHODS

Seven patients were enrolled on a clinical trial to assess the effect of MAL-PDT with biopsies taken at screening prior to the first treatment session (week 1), and six weeks after completion of final treatment (week 18). Whole-genome gene expression analysis was carried out on skin biopsies isolated from an AK lesion, an area surrounding the lesion, and a non-sun exposed region of the body. Quantitative PCR was utilized to confirm the differential expression of key genes.

RESULTS

MAL-PDT treatment corrected abnormal proliferation-related gene profiles, corrected aberrantly expressed cancer-associated genes and induced expression of dermal extracellular matrix genes in photo-exposed skin.

CONCLUSION

The efficacy of the MAL-PDT on AK lesions was confirmed at whole-genome gene expression level. A transcriptional signature of remodeling, identified through assessing the effect of MAL-PDT on photodamaged skin, supports the use of MAL-PDT for treating photodamaged skin and field cancerized areas.

Photodynamic therapy for aesthetic-cosmetic indications

Photodynamic therapy (PDT) is a well-established, non-invasive treatment for a variety of dermatologic disorders, including actinic keratosis. Furthermore, PDT results in marked improvements in the signs of skin aging, although currently there are no standardized guidelines for PDT in skin rejuvenation. Two types of PDT are available: conventional-PDT (c-PDT) and the newly introduced daylight-PDT (DL-PDT). Both require a topical photosensitizer, a light source and oxygen, and both are comparable regarding safety and efficacy for treatment of photo-induced skin aging. Treatment is particularly effective for improvement of fine wrinkles, skin roughness, actinic elastosis and mottled hyperpigmentation. The most widely studied topical sensitizers used in PDT are 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL). A range of pre-treatment procedures help improve skin absorption of the photosensitizer and lead to significantly improved efficacy. A variety of activating light sources can be used for c-PDT, while DL-PDT uses natural daylight, making it easier to treat larger areas of photodamaged skin. A major limitation of c-PDT is significant treatment-related pain, but DL-PDT has proved to be an almost pain-free procedure. Treatment duration is based on individual patient need but most patients receive 2 to 3 treatment cycles, with results fully evident 3-6 months post-treatment. PDT for aesthetic-cosmetic treatments has established its value in modern procedural dermatology as mono- or combination therapy. A major, unique advantage of PDT is that it is a non-invasive treatment that effectively rejuvenates photodamaged skin, while successfully treating a range of dermatologic conditions, including prevention and therapy of pre-cancerous actinic keratosis.

Skin photorejuvenation effects of light-emitting diodes (LEDs): a comparative study of yellow and red LEDs in vitro and in vivo

BACKGROUND

Red-coloured light-emitting diodes (LEDs) can improve skin photorejuvenation and regeneration by increasing cellular metabolic activity.

AIM

To evaluate the effectiveness of visible LEDs with specific wavelengths for skin photorejuvenation in vitro and in vivo.

METHODS

Normal human dermal fibroblasts (HDFs) from neonatal foreskin were cultured and irradiated in vitro by LEDs at different wavelengths (410-850 nm) and doses (0-10 J/cm(2) ). In vivo experiments were performed on the skin of hairless mice. Expression of collagen (COL) and matrix metalloproteinases (MMPs) was evaluated by semi-quantitative reverse transcription PCR (semi-qRT-PCR), western blotting and a procollagen type I C-peptide enzyme immunoassay (EIA). Haematoxylin and eosin and Masson trichrome stains were performed to evaluate histological changes.

RESULTS

In HDFs, COL I was upregulated and MMP-1 was downregulated in response to LED irradiation at 595 ± 2 and 630 ± 8 nm. In the EIA, a peak result was achieved at a dose of 5 J/cm(2) with LED at 595 ± 2 nm. In vivo, COL I synthesis was upregulated in a dose-dependent manner to both 595 and 630 nm LED irradiation, and this effect was prolonged to 21 days after a single irradiation with a dose of 100 J/cm(2) . These histological changes were consistent with the results of semi-qRT-PCR and western blots.

CONCLUSION

Specific LED treatment with 595 ± 2 and 630 ± 8 nm irradiation was able to modulate COL and MMPs in skin, with the effects persisting for at least 21 days after irradiation. These findings suggest that yellow and red LEDs might be useful tools for skin photorejuvenation.

Contribution of photodynamic therapy in wound healing: A systematic review

OBJECTIVE

We researched articles that used photodynamic therapy (PDT) for skin wound healing in humans.

METHODS

The systematic review was conducted through scientific articles that investigated the action of PDT on wound healing in humans, published from July 2005 to March 2017, in the data bases PubMed and LILACS.

RESULTS

The main types of wound described in selected articles in this review were chronic ulcer and non-melanoma skin cancer. For accomplishing the PDT, second generation of photosensitizing agents with laser or light emitting diode were used. The studies demonstrated that PDT contribute in several ways to the wound healing process: leading to cellular death; reducing or increasing inflammation; stimulating fibroblasts proliferation and, consequently, of collagen and elastin; raising transforming growth factor beta and metalloproteinases. Based on this, PDT provided good results in wound healing process, acting in several steps and accelerating tissue repair.

CONCLUSIONS

PDT improved healing in many wound models in humans, revealing itself as a promising therapeutic modality for stimulating wound healing and remodelling.

Chlorin e6-mediated photodynamic therapy promotes collagen production and suppresses MMPs expression via modulating AP-1 signaling in P. acnes-stimulated HaCaT cells

BACKGROUND

Photodynamic therapy (PDT) is a clinically approved therapeutic for cancers and non-neoplastic diseases, based on the use of a photosensitizer activated by light. The feasibility of PDT depends on several factors, such as PDT dose, photosensitizer efficacy, type of light source, and target tissue irradiated.

METHODS

In this study, the second generation photosensitizer chlorin e6 (Ce6) and halogen light were used to investigate their PDT effect on the collagen production and MMPs expression of heat killed P. acnes-stimulated HaCaT cells. The mRNA levels of COL1A1, c-Jun, and c-Fos were detected by RT-PCR. The protein levels of MMPs, ERK and JNK were detected by western blot. The transactivation of AP-1 was detected by luciferase assay.

RESULTS

Ce6-based PDT markedly upregulated the mRNA level of COL1A1 and type I procollagen level; and at the same time downregulated the expression of MMPs in P. acnes-infected HaCaT cells. Moreover, Ce6-mediated PDT, in a dose dependent manner, inhibited P. acnes-induced phosphorylation of JNK and ERK, as wells as the phosphorylation of their downstream targets c-Jun and c-Fos. P. acnes-induced mRNA expression of c-Jun and c-Fos were also suppressed by Ce6-mediated PDT. The transactivation of AP-1 induced by P. acnes infection was also downregulated.

CONCLUSION

These results indicated that Ce6-mediated PDT with halogen light enhanced collagen production, but inhibited the expression of MMPs in P. acnes-infected HaCaT cells, by regulating AP-1 signals. This investigation provided the first molecular basis for the increase in collagen production by Ce6-mediated PDT, suggesting its potential use for scar amelioration and skin rejuvenation in acne treatment.

Multiple sequential light and laser sources to activate aminolevulinic acid in the treatment of photodamage: A retrospective study

INTRODUCTION

The aim of this study was to retrospectively evaluate photodynamic therapy (PDT) with aminolevulinic acid (ALA) for cutaneous photorejuvenation using blue light sequentially with red light, pulsed-dye laser (PDL), and/or intense pulsed light (IPL).

MATERIALS AND METHODS

Ninety-six patients (121 treatments) had photodamage treated with field-directed ALA-PDT from 2001 to 2010 in this single-center study. Treatments were performed with blue light + PDL, blue light + IPL, blue light + PDL + IPL, or blue light + red light + PDL + IPL. Outcome measures were obtained via telephone questionnaire and graded on a four-point scale.

RESULTS

There were no significant differences in patient-reported improvement in photodamage, overall skin quality, and postprocedure adverse events between treatment arms. However, number of patients in the blue light + red light + PDL + IPL group was markedly smaller (n = 2) than that in the other groups (n = 14-46).

DISCUSSION

Although results showed a trend toward greater efficacy with similar tolerability using multiple, sequential light and laser sources with ALA-PDT for photorejuvenation, the potential for recall bias and widely disparate number of patients between treatment groups and follow-up times between patients severely limit this retrospective study. Nevertheless, despite these major statistical flaws, the results may provide valuable information regarding the safety of multiple modalities with PDT of photodamage in a single session.

Photodynamic Photorejuvenation: A Review

INTRODUCTION

Topical photodynamic therapy (PDT) is acknowledged to be a safe and efficient therapeutic option for the selective destruction of actinic keratosis and superficial carcinomas. Over the past 15 years, topical PDT has also been shown to be a possible method for "photorejuvenation."

MATERIALS AND METHODS

An extensive review was performed of in vitro and in vivo (animals, organ transplant recipients, or immunocompetent patients) studies.

RESULTS

The studies point to a high level of efficacy. Tone, lentigos, skin roughness, and moreover texture and fine wrinkles because of the effects of dermal remodeling are improved. Adverse effects are generally described as mild to moderate, without scarring, along with a fast recovery time. Patients with fair phototypes and a history of sun exposure and actinic damage of varying severity are the best candidates for this technique. Photodynamic photorejuvenation sessions can both rejuvenate their skins and also treat their visible or incipient UV-induced lesions. New protocols either with daylight use and/or previous intensification by laser or microneedling seem promising.

CONCLUSION

The photodynamic rejuvenation technique seems to show excellent short-term efficacy and tolerability.

Photodynamic therapy for skin rejuvenation: review and summary of the literature--results of a consensus conference of an expert group for aesthetic photodynamic therapy

Skin rejuvenating effects of photodynamic therapy (PDT) for photoaged skin has been well-documented in several clinical trials. Different photosensitizers (5-aminolevulinic acid, methyl aminolevulinate) and diverse light sources (light-emitting diodes, lasers, intense pulsed light) have been used with promising results. An improvement of lentigines, skin roughness, fine lines and sallow complexion has been achieved with PDT. These clinically evident effects are at least in part due to histologically proven increase of collagen and decrease of elastotic material in the dermis. Effective improvement of photoaged skin, simultaneous treatment and possibly also prevention of actinic keratoses, the possibility of repeated treatments and, in contrast to other procedures, limited and calculable side effects make PDT a promising procedure for skin rejuvenation.

Clinical, histopathological and immunohistochemical assessment of human skin field cancerization before and after photodynamic therapy

BACKGROUND

The field cancerization concept in photodamaged patients suggests that the entire sun-exposed surface of the skin has an increased risk for the development of (pre)-malignant lesions, mainly epithelial tumours. Topical photodynamic therapy (PDT) is a noninvasive therapeutic method for multiple actinic keratosis (AK) with excellent outcome.

OBJECTIVES

To evaluate the clinical, histological and immunohistochemical changes in human skin with field cancerization after multiple sessions of PDT with methyl-aminolaevulinate (MAL).

METHODS

Twenty-six patients with photodamaged skin and multiple AK on the face received three consecutive sessions of MAL-PDT with red light (37 J cm(-2)), 1 month apart. Biopsies before and 3 months after the last treatment session were taken from normal-appearing skin on the field-cancerized area. Immunohistochemical stainings were performed for TP-53, procollagen-I, metalloproteinase-1 (MMP-1) and tenascin-C (Tn-C).

RESULTS

All 26 patients completed the study. The global score for photodamage improved considerably in all patients (P < 0·001). The AK clearance rate was 89·5% at the end of the study. Two treatment sessions were as effective as three MAL-PDT sessions. A significant decrease in atypia grade and extent of keratinocyte atypia was observed histologically (P < 0·001). Also, a significant increase in collagen deposition (P = 0·001) and improvement of solar elastosis (P = 0·002) were noticed after PDT. However, immunohistochemistry showed only a trend for decreased TP-53 expression (not significant), increased procollagen-I and MMP-1 expressions (not significant) and an increased expression of Tn-C (P = 0·024).

CONCLUSIONS

Clinical and histological improvement in field cancerization after multiple sessions of MAL-PDT is proven. The decrease in severity and extent of keratinocyte atypia associated with a decreased expression of TP-53 suggest a reduced carcinogenic potential of the sun-damaged area. The significant increase of new collagen deposition and the reduction of solar elastosis explain the clinical improvement of photodamaged skin.