An ultra-sensitive biophysical risk assessment of light effect on skin cells

Phototherapy for age-related brain diseases: Challenges, successes and future

Brain diseases present a significant obstacle to both global health and economic progress, owing to their elusive pathogenesis and the limited effectiveness of pharmaceutical interventions. Phototherapy has emerged as a promising non-invasive therapeutic modality for addressing age-related brain disorders, including stroke, Alzheimer's disease (AD), and Parkinson's disease (PD), among others. This review examines the recent progressions in phototherapeutic interventions. Firstly, the article elucidates the various wavelengths of visible light that possess the capability to penetrate the skin and skull, as well as the pathways of light stimulation, encompassing the eyes, skin, veins, and skull. Secondly, it deliberates on the molecular mechanisms of visible light on photosensitive proteins, within the context of brain disorders and other molecular pathways of light modulation. Lastly, the practical application of phototherapy in diverse clinical neurological disorders is indicated. Additionally, this review presents novel approaches that combine phototherapy and pharmacological interventions. Moreover, it outlines the limitations of phototherapeutics and proposes innovative strategies to improve the treatment of cerebral disorders.

Blue light induces skin apoptosis and degeneration through activation of the endoplasmic reticulum stress-autophagy apoptosis axis: Protective role of hydrogen sulfide

Research on the phototoxicity of blue light (BL) to the skin is increasing. Although blue light can induce oxidative stress, inflammation, and inhibition of proliferation in skin cells, the mechanism by which blue light damages the skin is not yet clear. Endoplasmic reticulum (ER) stress and autophagy are two mechanisms by which cells resist external interference factors and maintain cell homeostasis and normal function, and both can affect cell apoptosis. Interestingly, we have found that blue light (435 nm ~ 445 nm, 8000 lx, 6-24 h)-induced oxidative stress triggers the ER stress-CHOP (C/EBP homologous protein) signal and affects the protein levels of B-cell lymphoma-2 (Bcl-2) and Bcl2-associated X (Bax), thereby promoting apoptosis. In addition, blue light activates autophagy in skin cells, which intensifies cell death. When ER stress is inhibited, autophagy is subsequently inhibited, suggesting that blue light-induced autophagy is influenced by ER stress. These evidences suggest that blue light induces activation of reactive oxygen species (ROS)-ER stress-autophagy-apoptosis axis signaling, which further induces skin injury and apoptosis. This is the first report on the relationships among oxidative stress, ER stress, autophagy, and apoptosis in blue light-induced skin injury. Furthermore, we have studied the effect of hydrogen sulfide (H₂S) on blue light-induced skin damage, and found that exogenous H₂S can protect skin from blue light-induced damage by regulating the ROS-ER stress-autophagy-apoptosis axis. Our data shows that when we are exposed to blue light, such as sunbathing and jaundice treatment, H₂S may be developed as a protective agent.

Role of Visible Light on Skin Melanocytes: A Systematic Review

In the last few years, the focus of phototherapy has shifted toward the visible (400-700 nm) part of the electromagnetic spectrum of light. Lately, it has been demonstrated that visible light (VL) can have both beneficial and detrimental effects, especially on the skin. Previously and until now, the most harmful effects on the skin are associated with ultraviolet radiation (UVR). After exposure to natural light, the most evident and immediate change is observed on skin pigmentation. Various wavelengths within the visible spectrum have been reported to alter skin pigmentation. However, the underlying mechanisms are incompletely understood so far. The article aims to shed light on the progress made in the photobiology field (photobiomodulation, PBM) to study the role of visible light on skin melanocytes.

The Aqueous Extract of Polypodium leucotomos (Fernblock®) Regulates Opsin 3 and Prevents Photooxidation of Melanin Precursors on Skin Cells Exposed to Blue Light Emitted from Digital Devices

The effects of sun exposure on the skin and specifically those related to pigmentation disorders are well known. It has recently been shown that blue light leads to the induction of oxidative stress and long-lasting pigmentation. The protective effect of an aqueous extract of Polypodium leucotomos (Fernblock^®) is known. Our aim was to investigate the action mechanism of Fernblock^® against pigmentation induced by blue light from digital devices. Human fibroblasts (HDF) and murine melanocytes (B16-F10) were exposed to artificial blue light (a 400–500 nm LED lamp). Cell viability, mitochondrial morphology, and the expression of the mitogen-activated protein kinase (MAPK) p38, known markers involved in the melanogenesis pathway, were evaluated. The activation of Opsin-3, a membrane protein sensitive to blue light that triggers the activation of the enzyme tyrosinase responsible for melanogenesis in melanocytes, was also analyzed. Our results demonstrated that pretreatment with Fernblock^® prevents cell death, alteration of mitochondrial morphology, and phosphorylation of p38 in HDF exposed to blue light. In addition, Fernblock^® significantly reduced the activation of Opsin-3 in melanocytes and the photo-oxidation of melanin, preventing its photodegradation. In sum, Fernblock^® exerts beneficial effects against the detrimental impact of blue light from digital devices and could prevent early photoaging, while maintaining skin homeostasis.

Environmentally-Induced (Extrinsic) Skin Aging: Exposomal Factors and Underlying Mechanisms

As a barrier organ, the skin is an ideal model to study environmentally-induced (extrinsic) aging. In this review, we explain the development of extrinsic skin aging as a consequence of skin exposure to specific exposomal factors, their interaction with each other, and the modification of their effects on the skin by genetic factors. We also review the evidence that exposure to these exposomal factors causes extrinsic skin aging by mechanisms that critically involve the accumulation of macromolecular damage and the subsequent development of functionally altered and/or senescent fibroblasts in the dermal compartment of the skin.

Melanoma in the Eyes of Mechanobiology

Skin is the largest organ of the human body with several important functions that can be impaired by injury, genetic or chronic diseases. Among all skin diseases, melanoma is one of the most severe, which can lead to death, due to metastization. Mechanotransduction has a crucial role for motility, invasion, adhesion and metastization processes, since it deals with the response of cells to physical forces. Signaling pathways are important to understand how physical cues produced or mediated by the Extracellular Matrix (ECM), affect healthy and tumor cells. During these processes, several molecules in the nucleus and cytoplasm are activated. Melanocytes, keratinocytes, fibroblasts and the ECM, play a crucial role in melanoma formation. This manuscript will address the synergy among melanocytes, keratinocytes, fibroblasts cells and the ECM considering their mechanical contribution and relevance in this disease. Mechanical properties of melanoma cells can also be influenced by pigmentation, which can be associated with changes in stiffness. Mechanical changes can be related with the adhesion, migration, or invasiveness potential of melanoma cells promoting a high metastization capacity of this cancer. Mechanosensing, mechanotransduction, and mechanoresponse will be highlighted with respect to the motility, invasion, adhesion and metastization in melanoma cancer.

Protective Effect of the Aqueous Extract of Deschampsia antarctica (EDAFENCE®) on Skin Cells against Blue Light Emitted from Digital Devices

Skin is being increasingly exposed to artificial blue light due to the extensive use of electronic devices. This, together with recent observations reporting that blue light—also known as high-energy visible light—can exert cytotoxic effects associated with oxidative stress and promote hyperpigmentation, has sparked interest in blue light and its potential harmful effects on skin. The photoprotective properties of new extracts of different botanicals with antioxidant activity are therefore being studied. Deschampsia antarctica (Edafence^®, EDA), a natural aqueous extract, has shown keratinocyte and fibroblast cell protection effects against ultraviolet radiation and dioxin toxicity. In this regard, we studied the protective capacity of EDA against the deleterious effects of artificial blue light irradiation in human dermal fibroblasts (HDF) and melanocytes. We analyzed the impact of EDA on viability, cell morphology, oxidative stress, melanogenic signaling pathway activation and hyperpigmentation in HDF and melanocytes subjected to artificial blue light irradiation. Our results show that EDA protects against cell damage caused by artificial blue light, decreasing oxidative stress, melanogenic signaling pathway activation and hyperpigmentation caused by blue light irradiation. All these findings suggest that EDA might help prevent skin damage produced by artificial blue light exposure from screen of electronic devices.

High-energy visible light at ambient doses and intensities induces oxidative stress of skin-Protective effects of the antioxidant and Nrf2 inducer Licochalcone A in vitro and in vivo

BACKGROUND

Solar radiation causes skin damage through the generation of reactive oxygen species (ROS). While UV filters effectively reduce UV-induced ROS, they cannot prevent VIS-induced (400-760 nm) oxidative stress. Therefore, potent antioxidants are needed as additives to sunscreen products.

METHODS

We investigated VIS-induced ROS formation and the photoprotective effects of the Nrf2 inducer Licochalcone A (LicA).

RESULTS

Visible spectrum of 400-500 nm dose-dependently induced ROS in cultured human fibroblasts at doses equivalent to 1 hour of sunshine on a sunny summer day (150 J/cm² ). A pretreatment for 24 hours with 1 µmol/L LicA reduced ROS formation to the level of unirradiated cells while UV filters alone were ineffective, even at SPF50+. In vivo, topical treatment with a LicA-containing SPF50 + formulation significantly prevented the depletion of intradermal carotenoids by VIS irradiation while SPF50 + control did not protect.

CONCLUSION

LicA may be a useful additive antioxidant for sunscreens.

Illumination with 630 nm Red Light Reduces Oxidative Stress and Restores Memory by Photo-Activating Catalase and Formaldehyde Dehydrogenase in SAMP8 Mice

AIMS

Pharmacological treatments for Alzheimer's disease (AD) have not resulted in desirable clinical efficacy over 100 years. Hydrogen peroxide (H₂O₂), a reactive and the most stable compound of reactive oxygen species, contributes to oxidative stress in AD patients. In this study, we designed a medical device to emit red light at 630 ± 15 nm from a light-emitting diode (LED-RL) and investigated whether the LED-RL reduces brain H₂O₂ levels and improves memory in senescence-accelerated prone 8 mouse (SAMP8) model of age-related dementia.

RESULTS

We found that age-associated H₂O₂ directly inhibited formaldehyde dehydrogenase (FDH). FDH inactivity and semicarbazide-sensitive amine oxidase (SSAO) disorder resulted in endogenous formaldehyde (FA) accumulation. Unexpectedly, excess FA, in turn, caused acetylcholine (Ach) deficiency by inhibiting choline acetyltransferase (ChAT) activity in vitro and in vivo. Interestingly, the 630 nm red light can penetrate the skull and the abdomen with light penetration rates of ∼49% and ∼43%, respectively. Illumination with LED-RL markedly activated both catalase and FDH in the brains, cultured cells, and purified protein solutions, all reduced brain H₂O₂ and FA levels and restored brain Ach contents. Consequently, LED-RL not only prevented early-stage memory decline but also rescued late-stage memory deficits in SAMP8 mice.

INNOVATION

We developed a phototherapeutic device with 630 nm red light, and this LED-RL reduced brain H₂O₂ levels and reversed age-related memory disorders.

CONCLUSIONS

The phototherapy of LED-RL has low photo toxicity and high rate of tissue penetration and noninvasively reverses aging-associated cognitive decline. This finding opens a promising opportunity to translate LED-RL into clinical treatment for patients with dementia. Antioxid. Redox Signal. 00, 000-000.

Efficacy of phototherapy to treat facial ageing when using a red versus an amber LED: a protocol for a randomised controlled trial

INTRODUCTION

The skin undergoes morphological and physiological changes with the advancing age of an individual. These changes may be caused by intrinsic and extrinsic factors that contribute to cellular ageing and consequent skin ageing. The term photoageing is used to characterise the ageing of the skin caused by solar radiation. Clinically, the skin becomes more flaccid, thicker and hyperpigmented, while there is an early appearance of wrinkles and other skin changes, such as skin cancer. Nowadays, there are numerous treatments for ageing skin, and one of them is with the use of phototherapy, which uses light-emitting diodes (LEDs). The objective of this study will be to evaluate the percentages of reduction in the volume of periocular wrinkles when treated with red and amber LEDs.

METHODS AND ANALYSIS

All of the participants will receive photobiomodulation to treat their periocular wrinkles. They will be using red and amber LEDs, with one colour being used on each hemiface. The facial side to be treated with each colour will be randomised. After an interval of 180 days, the participants will receive a cross-treatment. The primary variable of the study is the volume of periocular wrinkles (crow's feet), which will be measured by a VisioFace equipment. The secondary variables are elasticity (measured by Cutometer) and hydration (measured by Corneometer). Quality of life and self-assessment of the participants will be measured using the adapted Melasma Quality of Life scale - Brazilian Portuguese adaption (MelasQoL-BP) and Skindex-29 questionnaires. All of the variables will be measured before and after a group of 10 sessions.

ETHICS AND DISSEMINATION

This protocol was approved by the Research Ethics Committee of the Nove de Julho University (acceptance number: 2.550.732). This trial has been registered in the Registro Brasileiro de Ensaios Clínicos (Brazilian Clinical Trials Registry) (REBEC number: RBR-6YFCBM). This study is not recruiting yet.

TRIAL REGISTRATION NUMBER

RBR6YFCBM; Pre-results.

A microengineered human corneal epithelium-on-a-chip for eye drops mass transport evaluation

Animals are commonly used for pharmacokinetic studies which are the most frequent events tested during ocular drug development and preclinical evaluation. Inaccuracy, cost, and ethical criticism in these tests have created a need to construct an in vitro model for studying corneal constraints. In this work, a porous membrane embedded microfluidic platform is fabricated that separates a chip into an apical and basal side. After functionalizing the membrane surface with fibronectin, the membrane's mechanical and surface properties are measured to ensure correct modeling of in vivo characteristics. Immortalized human corneal epithelial cells are cultured on the membrane to create a microengineered corneal epithelium-on-a-chip (cornea chip) that is validated with experiments designed to test the barrier properties of the human corneal epithelium construct using model drugs. A pulsatile flow model is used that closely mimics the ocular precorneal constraints and is reasonable for permeability analysis that models in vivo conditions. This model can be used for preclinical evaluations of potential therapeutic drugs and to mimic the environment of the human cornea.

Mitochondrial damage and cytoskeleton reorganization in human dermal fibroblasts exposed to artificial visible light similar to screen-emitted light

BACKGROUND

Artificial visible light is everywhere in modern life. Social communication confronts us with screens of all kinds, and their use is on the rise. We are therefore increasingly exposed to artificial visible light, the effects of which on skin are poorly known.

OBJECTIVE

The purpose of this study was to model the artificial visible light emitted by electronic devices and assess its effect on normal human fibroblasts.

METHODS

The spectral irradiance emitted by electronic devices was optically measured and equipment was developed to accurately reproduce such artificial visible light. Effects on normal human fibroblasts were analyzed on human genome microarray-based gene expression analysis. At cellular level, visualization and image analysis were performed on the mitochondrial network and F-actin cytoskeleton. Cell proliferation, ATP release and type I procollagen secretion were also measured.

RESULTS

We developed a device consisting of 36 LEDs simultaneously emitting blue, green and red light at distinct wavelengths (450 nm, 525 nm and 625 nm) with narrow spectra and equivalent radiant power for the three colors. A dose of 99 J/cm2 artificial visible light was selected so as not to induce cell mortality following exposure. Microarray analysis revealed 2984 light-modulated transcripts. Functional annotation of light-responsive genes revealed several enriched functions including, amongst others, the "mitochondria" and "integrin signaling" categories. Selected results were confirmed by real-time quantitative PCR, analyzing 24 genes representing these two categories. Analysis of micro-patterned culture plates showed marked fragmentation of the mitochondrial network and disorganization of the F-actin cytoskeleton following exposure. Functionally, there was considerable impairment of cell growth and spread, ATP release and type I procollagen secretion in exposed fibroblasts.

CONCLUSION

Artificial visible light induces drastic molecular and cellular changes in normal human fibroblasts. This may impede normal cellular functions and contribute to premature skin aging. The present results extend our knowledge of the effects of the low-energy wavelengths that are increasingly used to treat skin disorders.

Electronic device generated light increases reactive oxygen species in human fibroblasts

OBJECTIVES

Our skin is constantly exposed to light from solar radiation and electronic devices, which impact skin physiology and aging. The biological altering properties of ultraviolet (UV) solar radiation on skin have been well established. There is significant scientific and public interest on the effects of electronic device generated light (EDGL) on skin. Currently, the effects of EDGL on skin are largely unknown. EDGL includes UV, visible, and infrared light from consumer electronics such as smartphones, computers, and televisions. In this study, we measured the wavelength specific irradiance from electronic devices, and irradiated fibroblasts with white EDGL to determine changes in reactive oxygen species generation, apoptosis, and necrosis.

METHODS

To determine the EDGL output of commonly used consumer electronic devices, we measured the irradiance from electronic devices at the manufacturers' recommended reading distances and at 1 cm. To determine the effect of EDGL on human skin cells, we irradiated AG13145 fibroblasts with EDGL for 1 hour at a distance of 1 cm and measured changes in reactive oxygen species generation, apoptosis, and necrosis.

RESULTS

ROS increased significantly by 81.71%, 85.79%, and 92.98% relative to control following 1 hour of white EDGL from iPhone 8+, iPhone 6, and iPad (first generation), respectively. There was a non-significant change in apoptosis following irradiation with an iPhone 8+, iPhone 6, and iPad. Total necrosis was less than 2% for all treatment and control groups.

CONCLUSIONS

Our results suggest that short exposures of EDGL increase ROS generation, but the long-term effects associated with repeated exposures of EDGL are unknown. As electronic devices become more widely used and integrated into society globally, we anticipate greater scientific research and general public interest on the effects of visible EDGL on skin. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.