Protective effects of a novel facial cream against environmental pollution: in vivo and in vitro assessment

Impact of nicotine-free and nicotine-rich flavored electronic cigarette refill liquids on primary human melanocyte function

In this study, five popular EC liquid flavors-strawberry, banana, vanilla, tobacco, and menthol-were examined on human melanocyte functions. Each flavored e-liquid (in 80/20 PG/VG vehicle) was tested without or with 18 mg/mL nicotine. The effects of PG/VG and nicotine-containing vehicles were also evaluated. Results revealed that nicotine-free and nicotine-containing e-liquids had comparable cytotoxicity, with menthol> > banana> tobacco> vanilla> strawberry. This cytotoxicity was unrelated to either nicotine or the vehicle. PG/VG (1 and 2 %) increased melanin production without influencing cellular tyrosinase activity. The flavored e-liquids did not further affect melanin production, suggesting that the vehicle's effect, not the flavor, was responsible for the increased melanin production. Interestingly, nicotine at 2 % in the vehicle restored the stimulated melanin production to the control. Flavors suppressed cellular tyrosinase activity, with vanilla and banana flavors robustly inhibiting it. Vanilla and banana e-liquids also enhanced reactive oxygen species (ROS) production, which did not originate from the vehicle or nicotine-containing vehicle. Banana e-liquid with nicotine lowered ROS generation compared to nicotine-free banana e-liquid. Common flavors in e-liquids can cause cytotoxicity and influence melanogenesis even without nicotine, indicating that the use of ECs may not completely avoid the harmful effects of cigarette smoking. Further studies are warranted to investigate e-liquid aerosol effects on melanocytes.

Pollution, a Relevant Exposome Factor in Skin Aging and the Role of Multi-benefit Photoprotection

Skin aging is a complex, continuous, multifactorial process resulting from cumulative morphological and functional changes in the skin over time. This happens because of 2processes: intrinsic and extrinsic skin aging. Intrinsic skin aging occurs naturally over time and reflects each person's genetic makeup, or heredity. Extrinsic skin aging, on the other hand, is due to exposomal factors, such as solar radiation, air pollution, tobacco or nutrition, being the first 2the most important of all. Exposure to air pollutants, primarily gases such as ground-level ozone and particulate matter, can accelerate the process via 4key mechanisms: reactive oxygen species generation, inflammation, skin microbiome disruption, and aryl hydrocarbon receptor activation. Regarding solar radiation, all wavelengths reaching the Earth's surface have an impact on the skin, having a synergistic effect with air pollution («photo-pollution»). Here, we discuss this phenomenon and mitigation strategies, including sunscreens, cosmetics with film-forming plus antioxidant ingredients, and oral supplementation.

Oxidative modification of collagen by malondialdehyde in porcine skin

Human skin is exposed to various physical and chemical stress factors, which commonly cause the oxidation of lipids and proteins. In this study, azo initiator AAPH [2,2' -azobis(2-methylpropionamidine) dihydrochloride] was employed to initiate lipid peroxidation in porcine skin as an ex vivo model for human skin. We demonstrate that malondialdehyde (MDA), a secondary product of lipid peroxidation, is covalently bound to collagen in the dermis, forming MDA-collagen adducts. The binding of MDA to collagen results in an unfolding of the collagen triple helix, formation of the dimer of α-chains of collagen, and fragmentation of the collagen α-chain. It is proposed here that the MDA is bound to the lysine residues of α-chain collagen, which are involved in electrostatic interaction and hydrogen bonding with the glutamate and aspartate of other α-chains of the triple helix. Our data provide crucial information about the MDA binding topology in the skin, which is necessary to understand better the various types of skin-related diseases and the aging process in the skin under stress.

Night Cream Containing Melatonin, Carnosine and Helichrysum italicum Extract Helps Reduce Skin Reactivity and Signs of Photodamage: Ex Vivo and Clinical Studies

Introduction

Extrinsic factors, such as solar radiation and urban pollution, cause damage that alters the structure, function and appearance of skin. The aim of this study was to determine the ability of a night cream containing melatonin, carnosine and Helichrysum italicum extract (referred to here as Night Cream) to reduce extrinsic skin damage, and to evaluate the efficacy of this Night Cream to reduce clinical signs of age and photodamage under normal conditions of use.

Methods

Recovery from extrinsic damage was assessed by exposing human skin explants to ultraviolet (UV) A, infrared light, blue light or pollution and then treating the stress-exposed explants with Night Cream. Markers of oxidative stress were examined by immunohistochemistry. Anti-aging and calming properties were determined in four single-center, open-label trials involving 117 individuals. Subjects applied Night Cream to their face once nightly for up to 12 weeks. Improvements in clinical signs of age and photodamage, and reduction of lactic acid-induced stinging were evaluated by investigator assessment and subject self-assessment.

Results

Night Cream significantly reduced oxidative stress in human skin ex vivo. Clinically, hydration (+ 64.4%; p < 0.05) and transepidermal water loss (TEWL) values (− 10.0%; p < 0.05) were improved within 1 h of use. Wrinkle counts were reduced by up to 18.9% (p < 0.05), and brown and UV spot numbers by 5.5% (p < 0.05) and 13.2% (p < 0.05), respectively. Lactic acid-induced stinging was significantly reduced within 7 days of use, with 86.7% of subjects reporting that their skin felt calmer.

Conclusion

These findings suggest that Night Cream reduces skin damage caused by environmental factors and that its nightly use can improve clinical signs of aging with additional skin calming benefits.

A novel water-based anti-aging suncare formulation provides multifaceted protection and repair against environmental aggressors: evidence from in vitro, ex vivo, and clinical studies

Background

Ultraviolet (UV) radiation is an established cause of skin aging, and the role of pollution is increasingly acknowledged. In this study, we evaluated the efficacy of an antipollution and anti-aging suncare product in in vitro, ex vivo, and clinical studies.

Methods

We assessed 1) sunburn cell (SBC) and cyclobutane pyrimidine dimer (CPD) formation and gene expression profile in reconstructed human epidermis following solar irradiation, 2) malondialdehyde (MDA) level, Nrf2 immunostaining, and genetic expression in skin explants exposed to pollution, 3) carbon particle adhesion to healthy forearm skin in a clinical study, and 4) skin firmness, elasticity, and pigmentation spots in healthy women following 56 days of application.

Results

1) The product fully protected against CPD formation, and provided a high protection against SBC formation, with levels close to non-irradiated samples. Expression of genes encoding pro-inflammatory and oxidative stress response markers was lower in product-treated than untreated skin. 2) Compared with pollution-exposed untreated controls, product-treated skin had 23% lower MDA levels (P<0.01), weaker Nrf2 immunostaining, and attenuated upregulation of CYP1A1. 3) The product significantly decreased adhesion of carbon particles to the skin (15.2% less than control; P<0.01). 4) Clinically, product use led to a decrease in brown spots, with a relative reduction in the count of −1.9% (NS), and in area, −5.0% (P<0.01), and decrease in UV spots, with a relative reduction of −6.9% (P<0.01) and −9.3% (P=0.02) for count and area, respectively. Firmness increased significantly by 14.1% (P<0.01). Participants reported skin was more even in tone (80%), more moisturized (93%), and firmer (74%).

Conclusion

This water-based anti-aging SPF50 suncare formulation containing photolyase encapsulated in liposome, active biopeptides, antioxidants, and hyaluronic acid provides multifaceted protection and repair action against pollution and UV-induced skin aging, ideal for everyday use.