Individual and combined effects of the infrared, visible, and ultraviolet light components of solar radiation on damage biomarkers in human skin cells

Assessment of Recovery Time Effects on Human Primary Neonatal Dermal Fibroblasts After Exposure to Solar-Simulated Ultraviolet Radiation

Introduction: Photoaging that is accompanied by gene expression alteration is known as early aging of the skin due to overexposure to natural and/or artificial ultraviolet radiation (UVR). The assessment of gene expression alteration in human primary neonatal dermal fibroblasts depending on recovery time after exposure to solar simulated ultraviolet radiation (ssUVR) is the main aim of this bioinformatic study. Methods: Data are extracted from Gene Expression Omnibus (GEO). The pre-evaluation is done via the GEO2R program. The Significant differentially expressed genes (DEGs) were assessed via protein-protein interaction (PPI) network analysis, and the central genes were identified. The central genes were enriched via gene ontology assessment. Results: Among 224 significant DEGs, 20 central genes including TOP2A, MKI67, BRCA1, HELLS, MAD2L1, ANLN, KIF11, MSH2, KRAS, NCAPG, RFC3, PLK4, WDHD1, BLM, CDKN3, KIF15, SMARCA5, and ATAD2 as hub genes and TOP2A, MKI67, BRCA1, ANLN, KRAS, PLK4, SMARCA5, MMP2, and TLR4 as bottleneck genes were determined. Eight central genes were associated with 16 biological terms. Conclusion: In conclusion, significant differences appeared between gene expression conditions of the cells after 1-day and 5-day recovery. Molecular events include the repair and continuation of photodamages. It is possible to introduce drug targets to prevent the progress of induced damages.

Melatonin/Sericin Wound Healing Patches: Implications for Melanoma Therapy

Melatonin and sericin exhibit antioxidant properties and may be useful in topical wound healing patches by maintaining redox balance, cell integrity, and regulating the inflammatory response. In human skin, melatonin suppresses damage caused by ultraviolet radiation (UVR) which involves numerous mechanisms associated with reactive oxygen species/reactive nitrogen species (ROS/RNS) generation and enhancing apoptosis. Sericin is a protein mainly composed of glycine, serine, aspartic acid, and threonine amino acids removed from the silkworm cocoon (particularly Bombyx mori and other species). It is of interest because of its biodegradability, anti-oxidative, and anti-bacterial properties. Sericin inhibits tyrosinase activity and promotes cell proliferation that can be supportive and useful in melanoma treatment. In recent years, wound healing patches containing sericin and melatonin individually have attracted significant attention by the scientific community. In this review, we summarize the state of innovation of such patches during 2021-2023. To date, melatonin/sericin-polymer patches for application in post-operational wound healing treatment has been only sparingly investigated and it is an imperative to consider these materials as a promising approach targeting for skin tissue engineering or regenerative dermatology.

Compound collagen peptide powder improves skin photoaging by reducing oxidative stress and activating TGF-β1/Smad pathway

Fish collagen peptide (FCP) has been extensively investigated as a natural product that can combat photoaging; however, its efficacy is limited by its singular composition. Compound collagen peptide powder (CCPP) is a novel functional food formulation that exhibits photoprotective properties and comprises FCP and a blend of natural botanical ingredients. The objective of this study was to investigate the efficacy of CCPP and its molecular mechanism. CCPP had a low molecular weight, facilitating its efficient absorption, and was abundant in amino acids, total polyphenols, and total flavonoids. The results of in vivo studies demonstrated that CCPP exhibited significant efficacy in reducing skin wrinkles, enhancing the contents of water and oil in the skin, and ameliorating histopathological alterations in mice. The results of in vitro studies demonstrated that CCPP effectively mitigated photoaging in human skin fibroblasts by attenuating oxidative stress and promoting extracellular matrix (ECM) synthesis. Moreover, we clearly demonstrated that the TGF β1/Smad pathway was involved in the promotion of ECM synthesis and cell proliferation by CCPP in human skin fibroblasts. These findings suggest that, compared with single collagen, CCPP has a more comprehensive range of antiphotoaging properties.

Time-lapse observation of mouse preimplantation embryos using a simple closed glass capillary method

Time-lapse observation is a popular method for analyzing mammalian preimplantation embryos, but it often requires expensive equipment and skilled techniques. We previously developed a simply and costly embryo-culture system in a sealed tube that does not require a CO2 incubator. In the present study, we developed a new time-lapse observation system using our previous culture method and a glass capillary. Zygotes were placed in a glass capillary and sunk in oil for observation under a stereomicroscope. Warming the capillary using a thermoplate enabled most of the zygotes to develop into blastocysts and produce healthy offspring. This time-lapse observation system captured images every 30 min for up to 5 days, which confirmed that the developmental speed and quality of the embryos were not affected, even with fluorescence. Overall, this new system is a simple time-lapse observation method for preimplantation embryos that does not require dedicated machines and advanced techniques.

Mesenchymal stem cell-derived exosomes and skin photoaging: From basic research to practical application

BACKGROUND

Skin photoaging is a condition caused by long-term exposure to ultraviolet irradiation, resulting in a variety of changes in the skin, such as capillary dilation, increased or absent pigmentation, dryness, sagging, and wrinkles. Stem cells possess a remarkable antioxidant capacity and the ability to proliferate, differentiate, and migrate, and their main mode of action is through paracrine secretion, with exosomes being the primary form of secretion. Stem cell-derived exosomes contain a variety of growth factors and cytokines and may have great potential to promote skin repair and delay skin ageing.

METHODS

This review focuses on the mechanisms of UV-induced skin photoaging, the research progress of stem cell exosomes against skin photoaging, emerging application approaches and limitations in the application of exosome therapy.

RESULT

Exosomes derived from various stem cells have the potential to prevent skin photoaging.

CONCLUSION

The combination with novel materials may be a key step for their practical application, which could be an important direction for future basic research and practical applications.

Electrospun Nanofibrous UV Filters with Bidirectional Actuation Properties Based on Salmon Sperm DNA/Silk Fibroin for Biomedical Applications

In this study, we dissolved Bombyx mori degummed silk [i.e., silk fibroin (SF)] and salmon sperm deoxyribonucleic acid (DNA) in water and used a bioinspired spinning process to obtain an electrospun nanofibrous SF-based patch (ESF). We investigated the bidirectional macroscale actuation behavior of ESF in response to water vapor and its UV-blocking properties as well as those of ESF/DNA films. Fourier transform infrared (FTIR) results suggest that the formation of β-sheet-rich structures promotes the actuation effect. ESF/DNA film with high-ordered and β-sheet-rich structures exhibits higher electrical conductivity and is water-insoluble. Given the intrinsic ability of both SF and DNA to absorb UV radiation, we performed biological experiments on the viability of keratinocyte HaCaT cells after exposure to solar spectrum components. Our findings indicate that the ESF/DNA patch is photoprotective and can increase the cellular viability of keratinocytes after UV exposure. Furthermore, we demonstrated that ESF/DNA patches treated with water vapor can serve as suitable scaffolds for tissue engineering and can improve tissue regeneration when cellularized with HaCaT cells. The 3D shape morphing capability of these patches, along with their potential as UV filters, could offer significant practical advantages in tissue engineering.

Broad-spectrum sunscreens containing the TriAsorB™ filter: In vitro photoprotection and clinical evaluation of blue light-induced skin pigmentation

BACKGROUND

Blue light (BL), particularly high-energy visible (HEV) light (400-450 nm), can cause skin damage and pigmentation. Therefore, effective sunscreens should offer photoprotection beyond ultraviolet (UV) radiation to also prevent or limit BL-induced cutaneous effects.

OBJECTIVES

To evaluate the in vitro BL photostability and photoprotection properties of nine sunscreens containing the broad-spectrum UV/BL phenylene bis-diphenyltriazine (PBDT or TriAsorB™) filter, together with three other organic UV filters, and to assess the in vivo photoprotection level provided by two of these products against BL-induced skin pigmentation.

METHODS

In vitro BL photostability and photoprotection factors, comprising the percentage of BL radiation stopped by the product (%BL) and the critical wavelength extended to BL (BL-CW), were determined by spectrophotometry. The in vivo photoprotection provided by two representative sunscreens (i.e. similar formulations, one non-tinted and one tinted) was assessed in two open randomized studies (20 and 16 women, respectively) after exposure of two test areas (with and without sunscreen) on the back of each subject to a 412-nm irradiation dose at 50 J/cm2 , using instrumental and clinical measurements of skin pigmentation. The percentage sunscreen photoprotective effectiveness (%PPE) was calculated by comparing intrasubject post-exposure pigmentation changes between the with and without sunscreen test areas.

RESULTS

In vitro, the nine PBDT-containing products were highly photostable and had a BL-CW ≥385 nm and a %BL ≥30% (range: 30%-50%), thus allowing effective BL photoprotection. In vivo, both representative sunscreens prevented BL-induced immediate skin pigmentation (1 and 24 h post-exposure) with %PPE values ranging from 50.7% to 75.5% for colorimetric assessments (p < 0.001) and from 31.2% to 72.7% for visual scores (p ≤ 0.001).

CONCLUSIONS

All PBDT-containing sunscreens were considered effective at absorbing BL radiation in vitro. The two representative broad-spectrum sunscreens tested in subjects significantly reduced BL-induced immediate skin pigmentation following single exposure to monochromatic BL radiation.

Effect of red light on epidermal proliferation and mitochondrial activity

BACKGROUND/PURPOSE

We previously demonstrated that irradiation with red light accelerates recovery of the epidermal water-impermeable barrier, whereas blue light delays it, and white and green light have no effect. Here, we aimed to examine in detail the effects of red and blue light in a human epidermal-equivalent model and in human skin.

METHODS

We used light-emitting diodes (red light, 630 nm, 6.2 mW/cm2 ; blue light, 463 nm, 6.2 mW/cm2 ) for irradiation of an epidermal-equivalent model and human skin. Cell proliferation was evaluated by means of BrdU and Ki-67 staining, and mitochondrial activity was quantified with an extracellular flux analyzer.

RESULTS

Irradiation of the epidermal-equivalent model with red light for 2 h (44.64 J/cm2 ) increased both epidermal proliferation in the basal layer and mitochondrial activity. Blue light had no effect on epidermal proliferation. Furthermore, irradiation with red light for 2 h on three consecutive days increased epidermal proliferation in human skin tissue in culture.

CONCLUSION

These results suggest that red light accelerates epidermal proliferation in both an epidermal-equivalent model and human skin, and may promote epidermal homeostasis.

[Skin aging exposome]

The skin is a barrier organ and thus exposed to environmental factors from birth, which essentially determine skin aging. In order to describe and understand this complex process exactly, we applied the concept of the "exposome" to the environmentally induced skin aging process. In this review, we summarize current knowledge on the skin aging exposome. In this context, we characterize the most important exposomal factors, address their relative importance for skin aging and also the relevance of their mutual interactions. Finally, we discuss the clinical consequences resulting from this concept for an effective prevention of skin aging.

Development of Salmon Sperm DNA/Regenerated Silk Bio-Based Films for Biomedical Studies on Human Keratinocyte HaCaT Cells under Solar Spectrum

In this study, we fabricated adhesive patches from silkworm-regenerated silk and DNA to safeguard human skin from the sun's rays. The patches are realized by exploiting the dissolution of silk fibers (e.g., silk fibroin (SF)) and salmon sperm DNA in formic acid and CaCl₂ solutions. Infrared spectroscopy is used to investigate the conformational transition of SF when combined with DNA; the results indicated that the addition of DNA provides an increase in the SF crystallinity. UV-Visible absorption and circular dichroism spectroscopy showed strong absorption in the UV region and the presence of B-form of DNA once dispersed in the SF matrix, respectively. Water absorption measurements as well as thermal dependence of water sorption and thermal analysis, suggested the stability of the fabricated patches. Biological results on cellular viability (MTT assay) of keratinocyte HaCaT cells after exposures to the solar spectrum showed that both SF and SF/DNA patches are photo-protective by increasing the cellular viability of keratinocytes after UV component exposure. Overall, these SF/DNA patches promise applications in wound dressing for practical biomedical purposes.

Cotton Woven Fabrics as Protective Polymer Materials against Solar Radiation in the Range of 210-1200 nm

The proposed paper describes the influence of woven fabric constructional parameters (type of weave, relative fabric density) and colouration (obtained by eco-friendly dyeing) on the solar transmittance of cotton woven fabrics in the range of 210-1200 nm. The cotton woven fabrics in their raw state were prepared according to Kienbaum's setting theory, at three levels of relative fabric density and three levels of the weave factor, and then exposed to the dyeing process with natural dyestuffs (beetroot, walnut leaves). After ultraviolet/visible/near-infrared (UV/VIS/IRA) solar transmittance and reflection in the range of 210-1200 nm were recorded, the influence of the fabric construction and colouration were analysed. The guidelines for fabric constructor were proposed. The results show that the walnut-coloured satin samples at the third level of relative fabric density provide the best solar protection in the whole solar spectrum. All the tested eco-friendly dyed fabrics offer good solar protection, while only raw satin fabric at the third level of relative fabric density can be classified as solar protective material with even better protection in IRA region than some coloured samples.

Photoprotection in skin of color

As populations in many parts of the world are projected to become more racially diverse over the coming decades, we must better understand the unique characteristics of the skin of populations with skin of color (SOC). This review aims to highlight important physiologic and clinical considerations of photoprotection in SOC. Ultraviolet radiation and visible light affect dark and light skin differently. SOC populations have historically not been informed on photoprotection to the same degree as their light skinned counterparts. This has exacerbated dermatologic conditions in which SOC populations are disproportionately affected, such as hyperpigmentary disorders. Patients should be encouraged to utilize multiple methods of photoprotection, ranging from avoidance of sunlight during peak intensity hours, seeking shade, wearing sun-protective clothing and wide-brimmed hat, and applying sunscreen. Ideal sunscreens for SOC populations include those with UVA-PF/SPF ratios ≥ 2/3 and tinted sunscreens to protect against VL. Although there have been increased efforts recently, more research into photoprotection for SOC and targeted public education are required to disseminate photoprotection resources that are patient-centered and evidence-based.

Designing a Band for Vehicles' Drivers Induced by Ultraviolet and Infrared Radiations

Background

Solar radiations that reach the Earth can be divided into ultraviolet, visible light, and infrared. Overexposure to these radiations can facilitate adverse skin diseases such as sunburn, skin cancer, and photoaging. People who drive vehicles for an extended period are likely to develop skin cancer in the exposed body area.

Method

This research proposes a wearable protective device around the upper arm to measure the transmitted radiation through the front and the side windows. A novel skin type classification algorithm using a color sensor was created to provide an accurate skin type identification. Also, the device was programmed to calculate the time before sunburn occurrence based on the ultraviolet index, sunscreen's sun protection factor, and skin type.

Results

The prototype was tested inside a Toyota Camry model 2001 vehicle with an accuracy of 97%. The front window had transmitted more infrared radiation compared to the side window. The highest recorded value was 76.76 mW/cm². On the other hand, the side window had transmitted more ultraviolet compared to the front window as it lacks the protective polyvinyl butyral layer that the front window has. The highest recorded ultraviolet index was 3.5.

Conclusion

These results highlight the importance of wearing the designed solar band and using appropriate UV and IR protection while driving a vehicle to prevent skin diseases from occurring.

The Damaging Effects of Long UVA (UVA1) Rays: A Major Challenge to Preserve Skin Health and Integrity

Within solar ultraviolet (UV) light, the longest UVA1 wavelengths, with significant and relatively constant levels all year round and large penetration properties, produce effects in all cutaneous layers. Their effects, mediated by numerous endogenous chromophores, primarily involve the generation of reactive oxygen species (ROS). The resulting oxidative stress is the major mode of action of UVA1, responsible for lipid peroxidation, protein carbonylation, DNA lesions and subsequent intracellular signaling cascades. These molecular changes lead to mutations, apoptosis, dermis remodeling, inflammatory reactions and abnormal immune responses. The altered biological functions contribute to clinical consequences such as hyperpigmentation, inflammation, photoimmunosuppression, sun allergies, photoaging and photocancers. Such harmful impacts have also been reported after the use of UVA1 phototherapy or tanning beds. Furthermore, other external aggressors, such as pollutants and visible light (Vis), were shown to induce independent, cumulative and synergistic effects with UVA1 rays. In this review, we synthetize the biological and clinical effects of UVA1 and the complementary effects of UVA1 with pollutants or Vis. The identified deleterious biological impact of UVA1 contributing to clinical consequences, combined with the predominance of UVA1 rays in solar UV radiation, constitute a solid rational for the need for a broad photoprotection, including UVA1 up to 400 nm.

Is the Technology Era Aging You? A Review of the Physiologic and Psychologic Toll of Technology Use

BACKGROUND

Technology use is at an all-time high and its potential impact on psychological and physiologic health should be explored.

OBJECTIVE

The objective of this narrative review was to identify the role of technology use on health and well-being.

MATERIALS AND METHODS

Authors performed a review of PubMed and publications of the World Health Organization, Department of Defense, and Centers for Disease Control and Prevention to determine the impact of technology regarding electromagnetic radiation (EM), posture and mobility, sleep disturbance, and psychological stress and well-being.

RESULTS

Studies on the impact of EM were conflicting, with about 45% reporting negative consequences and 55% reporting no effect. Radiofrequency EM (RF-EM) may more significantly affect fibroblasts and immature cells. Device use was implicated in worsening cognitive focus, imbalance, and sleep. Social media use affects self-esteem and mental health and is associated with up to 33% presence of addiction. Effects seem to be dose related and more pronounced in younger ages.

CONCLUSION

Technology use significantly affects sleep, mental health, and cognitive function. Seeking psychological help, limiting social media use, and reducing use before sleep may partially mitigate these effects. The impact of EM is undetermined, but the WHO lists RF-EM as a potential carcinogen.

The Molecular Mechanism of Polyphenols with Anti-Aging Activity in Aged Human Dermal Fibroblasts

Skin is the largest organ in the body comprised of three different layers including the epidermis, dermis, and hypodermis. The dermis is mainly composed of dermal fibroblasts and extracellular matrix (ECM), such as collagen and elastin, which are strongly related to skin elasticity and firmness. Skin is continuously exposed to different kinds of environmental stimuli. For example, ultraviolet (UV) radiation, air pollutants, or smoking aggravates skin aging. These external stimuli accelerate the aging process by reactive oxygen species (ROS)-mediated signaling pathways and even cause aging-related diseases. Skin aging is characterized by elasticity loss, wrinkle formation, a reduced dermal-epidermal junction, and delayed wound healing. Thus, many studies have shown that natural polyphenol compounds can delay the aging process by regulating age-related signaling pathways in aged dermal fibroblasts. This review first highlights the relationship between aging and its related molecular mechanisms. Then, we discuss the function and underlying mechanism of various polyphenols for improving skin aging. This study may provide essential insights for developing functional cosmetics and future clinical applications.

Urolithin A protects human dermal fibroblasts from UVA-induced photoaging through NRF2 activation and mitophagy

Photoaging, caused by exposure to sunlight and especially UVA, has been identified as one of the culprits for age-related skin deterioration. Here, we initially demonstrated that urolithin A (UroA), a metabolite derived from intestine microflora, possessed sufficient photoprotective capacity and attenuated UVA-induced senescent phenotypes in human fibroblasts, such as growth inhibition, senescence-associated β-galactosidase activity, breakdown of extracellular matrix, synthesis of senescence-associated secretory phenotypes and cell cycle arrest. Furthermore, UroA lessened the accumulation of intracellular reactive oxygen species, which promoted the phosphorylation and afterwards nuclear translocation of NRF2, subsequently driving the activation of downstream antioxidative enzymes. In parallel, we proved that UroA restored mitochondrial function by induction of mitophagy, which was regulated by the SIRT3-FOXO3-PINK1-PARKIN network. Taken together, our results showed that UroA protected dermal fibroblast from UVA damage through NRF2/ARE activation and mitophagy process, thus supporting UroA as a potential therapeutic agent for photoaging.

Development and characterisation of an irradiation device for biomedical studies covering the solar spectrum with individual regulated spectral bands

To understand the importance of terrestrial solar exposure on human skin, not only individual spectral components need to be considered in biomedical studies, but also the relevance of the combined action profile of the complete solar spectrum (cSS) must be established. We therefore developed a novel irradiation device that combines the emission of four individual lamps (UVB, UVA, VIS and nIR) to achieve exposure from 280 to 1400 nm with individual controllable lamps. The integrated irradiance of each spectral band is similar to the solar spectrum. The lamps can be utilised individually or in any desired combination. Here we present the design, realisation, and validation of this irradiation device as well as biological results on cellular metabolism (MTT assay), cell cycle alterations, and clonogenic growth in HaCaT cells after exposures to the individual spectral bands as well as their simultaneous combinations. Thereby, we demonstrate that UVB combined with UVA is the main determinant for the metabolic activity within cSS. Also, UVB-dependent effects dominate cell cycle regulation in cSS, whilst UVA and nIR have little influence. Lastly, also clonogenic growth is dominated by the UVB action profile in cSS, despite nIR showing modulatory activity when applied in combination with UVB. Together, this highlights the regulatory influence of the different spectral bands on the three biological endpoints and demonstrates their modulation when being part of the complete solar spectrum.

Formulation of a new broad-spectrum UVB + UVA and blue light SPF50+ sunscreen containing Phenylene Bis-Diphenyltriazine (TriAsorB), an innovative sun filter with unique optical properties

Accumulating evidence from numerous comprehensive studies has demonstrated that blue light, in particular high-energy visible light, can exert a range of harmful effects on skin cells. These forms of radiation are now known to be able to trigger oxidation reactions, DNA damage, erythema and pigmentary changes, and may also be associated with photoaging. Sunscreens protecting the skin from only ultraviolet (UV)-B and UVA rays can therefore no longer be regarded as sufficient to help prevent skin damage from sunlight, and products containing filters that can provide broad-spectrum photoprotection are required. To meet this need, a new sunscreen formulation that provides photoprotection against solar radiation with wavelengths ranging from UV to visible light has been developed, using an innovative organic sun filter with unique optical properties: phenylene bis diphenyltriazine (TriAsorB™). This article outlines the development and characteristics of this innovative filter and describes new key results from studies performed to assess the effectiveness and safety of the filter and the new sunscreen product. The studies conducted so far demonstrate that the filter has a good human and environmental safety profile. In addition, the sunscreen, which contains TriAsorB in combination with three other UV filters to offer broad-spectrum sun protection with a high sun protection factor (SPF50⁺ ), appears to effectively prevent multiple forms of cellular photodamage, in particular blue light-induced oxidatively generated DNA lesions. Overall, the available data indicate that regular use of the TriAsorB-containing sunscreen could help prevent solar radiation-induced skin damage and the development of signs of premature skin aging, as well as photodermatoses caused or exacerbated by visible light.

Effects of visible light on mechanisms of skin photoaging

Human skin is not only affected by ultraviolet radiation but also by visible light wavelengths emitted by sunlight, electronic devices, and light emitting diodes. Similar to the ultraviolet radiation, visible light has been implicated in photoaging. In this review, the effects of blue light, yellow light, red light, and broad visible light are discussed in relation with photoaging. Different visible light wavelengths likely contribute beneficial and deleterious effects on photoaging by way of interaction with specific photoreceptors, ROS production, and other photon-mediated reactions. Further in vivo studies are needed to determine the mechanism and action spectrum of photoaging in humans, as well as optimal photoprotection with coverage against visible light wavelengths.

Wearable Light Sensors Based on Unique Features of a Natural Biochrome

Overexposure to complete solar radiation (combined ultraviolet, visible, and infrared) is correlated with several harmful biological consequences including hyperpigmentation, skin cancer, eye damage, and immune suppression. With limited effective therapeutic options available for these conditions, significant efforts have been directed toward promoting preventative habits. Recently, wearable solar radiometers have emerged as practical tools for managing personal exposure to sunlight. However, designing simple and inexpensive sensors that can measure energy across multiple spectral regions without incorporating electronic components remains challenging, largely due to inherent spectral limitations of photoresponsive indicators. In this work, we report the design, fabrication, and characterization of wearable radiation sensors that leverage an unexpected feature of a natural biochrome, xanthommatin-its innate sensitivity to both ultraviolet and visible through near-infrared radiation. We found that xanthommatin-based sensors undergo a visible shift from yellow to red in the presence of complete sunlight. This color change is driven by intrinsic photoreduction of the molecule, which we investigated using computational modeling and supplemented by radiation-driven formation of complementary reducing agents. These sensors are responsive to dermatologically relevant doses of erythemally weighted radiation, as well as cumulative doses of high-energy ultraviolet radiation used for germicidal sterilization. We incorporated these miniature sensors into pressure-activated microfluidic systems to illustrate on-demand activation of a wearable and mountable form factor. When taken together, our findings encompass an important advancement toward accessible, quantitative measurements of UVC and complete solar radiation for a variety of use cases.

Mechanistic Insights of Chelator Complexes with Essential Transition Metals: Antioxidant/Pro-Oxidant Activity and Applications in Medicine

The antioxidant/pro-oxidant activity of drugs and dietary molecules and their role in the maintenance of redox homeostasis, as well as the implications in health and different diseases, have not yet been fully evaluated. In particular, the redox activity and other interactions of drugs with essential redox metal ions, such as iron and copper, need further investigation. These metal ions are ubiquitous in human nutrition but also widely found in dietary supplements and appear to exert major effects on redox homeostasis in health, but also on many diseases of free radical pathology. In this context, the redox mechanistic insights of mainly three prototype groups of drugs, namely alpha-ketohydroxypyridines (alpha-hydroxypyridones), e.g., deferiprone, anthraquinones, e.g., doxorubicin and thiosemicarbazones, e.g., triapine and their metal complexes were examined; details of the mechanisms of their redox activity were reviewed, with emphasis on the biological implications and potential clinical applications, including anticancer activity. Furthermore, the redox properties of these three classes of chelators were compared to those of the iron chelating drugs and also to vitamin C, with an emphasis on their potential clinical interactions and future clinical application prospects in cancer, neurodegenerative and other diseases.

The roles of mitochondrial dynamics and NLRP3 inflammasomes in the pathogenesis of retinal light damage

With the widespread popularity of electronic products and the diversification of lighting equipment, ocular photochemical damage caused by light has attracted research attention. Although such equipment mainly cause damage to the retina, the specific pathogenesis has not been systematically elucidated. Thus, the goal of this study was to explore the relationship between mitochondrial dysfunction and the activation of the NOD-like receptor protein 3 (NLRP3) inflammasome in retinal cell death caused by light damage. We used a white light-emitting diode source to establish a mouse model of retinal light damage and observed significant changes of retinal structure and an impairment of visual function. Further experiments revealed that dynamin-related protein 1 (Drp1)-mediated excessive mitochondrial fission induced overproduction of reactive oxygen species in the retinal cells, leading to apoptosis, activation of microglia, and formation of the NLRP3 inflammasome. This, in turn, triggered a series of inflammatory cascade reactions, leading to pyroptosis. We also carried out red light and Drp1 inhibitor treatment and found that retinal damage and the decline in visual function caused by white light could be partially ameliorated. In conclusion, this study clarified the association between mitochondrial dynamics and the NLRP3 inflammasome in retinal light damage and provides opportunities for therapeutic intervention.

Lignin Nanoparticles and Their Nanocomposites

Lignin nanomaterials have emerged as a promising alternative to fossil-based chemicals and products for some potential added-value applications, which benefits from their structural diversity and biodegradability. This review elucidates a perspective in recent research on nanolignins and their nanocomposites. It summarizes the different nanolignin preparation methods, emphasizing anti-solvent precipitation, self-assembly and interfacial crosslinking. Also described are the preparation of various nanocomposites by the chemical modification of nanolignin and compounds with inorganic materials or polymers. Additionally, advances in numerous potential high-value applications, such as use in food packaging, biomedical, chemical engineering and biorefineries, are described.

An update in toxicology of ageing

The field of ageing research has been rapidly advancing in recent decades and it had provided insight into the complexity of ageing phenomenon. However, as the organism-environment interaction appears to significantly affect the organismal pace of ageing, the systematic approach for gerontogenic risk assessment of environmental factors has yet to be established. This puts demand on development of effective biomarker of ageing, as a relevant tool to quantify effects of gerontogenic exposures, contingent on multidisciplinary research approach. Here we review the current knowledge regarding the main endogenous gerontogenic pathways involved in acceleration of ageing through environmental exposures. These include inflammatory and oxidative stress-triggered processes, dysregulation of maintenance of cellular anabolism and catabolism and loss of protein homeostasis. The most effective biomarkers showing specificity and relevancy to ageing phenotypes are summarized, as well. The crucial part of this review was dedicated to the comprehensive overview of environmental gerontogens including various types of radiation, certain types of pesticides, heavy metals, drugs and addictive substances, unhealthy dietary patterns, and sedentary life as well as psychosocial stress. The reported effects in vitro and in vivo of both recognized and potential gerontogens are described with respect to the up-to-date knowledge in geroscience. Finally, hormetic and ageing decelerating effects of environmental factors are briefly discussed, as well.

Daily photoprotection to prevent photoaging

BACKGROUND

Extrinsic skin aging or photoaging was previously thought to be almost exclusively due to solar ultraviolet (UV) radiation. However, recent literature has described other contributing factors and clarification is thus required as to what extent and what type of daily photoprotection is needed to mitigate extrinsic skin aging.

METHODS

We reviewed the existing scientific evidence on daily photoprotection, and specific requirements at the product level, to prevent extrinsic skin aging. We critically reviewed the existing evidence on potential ecological and toxicological risks which might be associated with daily photoprotection.

RESULTS

Evidence shows that broad protection against the entire solar range of UVB, UVA, UVA1, visible light, and short infrared (IRA) is required to prevent extrinsic aging. Other exposome factors, such as air pollution and smoking, also contribute to skin aging. Daily broad-spectrum sunscreen photoprotection should thus contain antioxidant ingredients for additional benefits against UV, IRA, and pollution-induced oxidative stress as well as anti-aging active ingredients to provide clinical benefits against skin aging signs, such as wrinkles and dark spots. Broad-spectrum sunscreen containing pigments, such as iron oxide, may be required for melasma prevention. There is no conclusive clinical evidence that daily sunscreen use is unsafe or that it compromises vitamin D synthesis.

CONCLUSION

Daily use of broad-spectrum sunscreen containing antioxidant and anti-aging active ingredients can effectively reduce extrinsic aging.

In vivo determination of the Infrared-A protection factor on human skin

BACKGROUND

Chronic exposure to infrared A (IR-A) irradiation causes photoaging. However, daily or acute exposure to IR-A rarely induces erythema or pigmentation. Thus, evaluation of the physiological changes taking place on the skin surface is insufficient for clinical investigations.

MATERIALS AND METHODS

We fabricated a novel device to obtain the IR-A protection factor (IPF) on human skin. This device consists of an artificial light source that mimics the actual IR-A intensity of sunlight, and a spectrophotometer to measure the spectral reflectance on the skin surface. The IPF can be determined by measuring the difference in spectral reflectance on the skin before and after the use of products and can be verified by the statistical criterion. A validation study was performed using different light intensities and two experimenters. Finally, we monitored the IPF on 12 commercial cosmetics.

RESULTS

After considering the IPF and L*-values, we selected the optimal sample and performed a validation study. Neither the intensity of IR-A irradiation or the experimenters significantly affected the IPF. 12 commercial products exhibited their own IPF values and were verified by statistical criteria, with one exception.

CONCLUSION

The present IPF evaluation method was concluded to be robust and reliable. This method is simple and safe for the subjects, and could be helpful for the development of IR-A protection products and the confirmation of product performances.

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.

Introduction to Environmental Harmful Factors

In this Chapter, we systematically and comprehensively described various environmental harmful factors. They were classified into four aspects: physical factors, chemical factors, biological factors, and physiological and psychological stress factors. Their classification, modes of presence, toxicity and carcinogenicity, routes of exposure to human and toxic effects on the female reproductive health were introduced. It is expected that the exposure routes could be controlled and eliminated, and the pathogenic mechanism of environmental harmful factors should be investigated and explained to protect female reproductive health.

Lignin-Based Sunscreens—State-of-the-Art, Prospects and Challenges

This review covers the latest developments and challenges in the field of broad-spectrum sunscreens and how sunscreens based on lignin address their requirements in terms of sunlight protection, antioxidants, and preservatives.

Individual and combined effects of the infrared, visible, and ultraviolet light components of solar radiation on damage biomarkers in human skin cells

The ability of solar ultraviolet (UV) to induce skin cancer and photoaging is well recognized. The effect of the infrared (IR) and visible light (Vis) components of solar radiation on skin and their interaction with UV is less well known. This study compared the effects of physiologically relevant doses of complete (UV + Vis + IR) solar-simulated light and its individual components on matched primary dermal fibroblasts and epidermal keratinocytes from human donors on three biomarkers of cellular damage (reactive oxygen species (ROS) generation, mitochondrial DNA (mtDNA), and nuclear DNA (nDNA) damage). There was a greater induction of ROS, mtDNA, and nDNA damage with the inclusion of the visible and IR components of solar-simulated light in primary fibroblast cells compared to primary keratinocytes (P < .001). Experiments using exposure to specific components of solar light alone or in combination showed that the UV, Vis, and IR components of solar light synergistically increased ROS generation in primary fibroblasts but not primary keratinocytes (P < .001). Skin cell lines were used to confirm these findings. These observations have important implications for different skin cell type responses to the individual and interacting components of solar light and therefore photodamage mechanisms and photoprotection interventions.

Role of Damage-Associated Molecular Patterns in Light of Modern Environmental Research: A Tautological Approach

Two prominent models emerged as a result of intense interdisciplinary discussions on the environmental health paradigm, called the "exposome" concept and the "adverse outcome pathway" (AOP) concept that links a molecular initiating event to the adverse outcome via key events. Here, evidence is discussed, suggesting that environmental stress/injury-induced damage-associated molecular patterns (DAMPs) may operate as an essential integrating element of both environmental health research paradigms. DAMP-promoted controlled/uncontrolled innate/adaptive immune responses reflect the key events of the AOP concept. The whole process starting from exposure to a distinct environmental stress/injury-associated with the presence/emission of DAMPs-up to the manifestation of a disease may be regarded as an exposome. Clinical examples of such a scenario are briefly sketched, in particular, a model in relation to the emerging COVID-19 pandemic, where the interaction of noninfectious environmental factors (e.g., particulate matter) and infectious factors (SARS CoV-2) may promote SARS case fatality via superimposition of both exogenous and endogenous DAMPs.