Christian Oresajo

Protective effects of a topical antioxidant mixture containing vitamin C, ferulic acid, and phloretin against ultraviolet-induced photodamage in human skin

Background  Ultraviolet (UV) irradiation of the skin leads to acute inflammatory reactions, such as erythema, sunburn, and chronic reactions, including premature skin aging and skin cancer.

Antioxidants and the skin: Understanding formulation and efficacy

Antioxidants are molecules capable of inhibiting the oxidation of other molecules. Although oxidation reactions are essential for life, they can also be damaging. All living organisms maintain complex systems of multiple types of antioxidants to protect their cells from oxidative damage. Antioxidants can also act as pro‐oxidants, under certain circumstances. The efficacy and benefit of an antioxidant is, therefore, very much dependent on the delivery of the antioxidant to the organism. Topically applied antioxidants constitute an important group of pharmacologically active agents capable of preventing the occurrence and reducing the severity of UV‐induced skin damage and skin aging. Antioxidants protect skin cells against the damaging effects of reactive oxygen species (ROS), such as singlet oxygen, superoxide, peroxyl radicals, hydroxyl radicals, and peroxynitrite. ROS induced oxidative stress in the skin has been linked to cancer, aging, inflammation, and photodamage. This review focuses on antioxidants used in the cosmetic industry for protection of skin, formulation methods used to enhance their efficacy, and methods used to test the efficacy of antioxidants in topical formulations.

Vitamin C Compound Mixtures Prevent Ozone-Induced Oxidative Damage in Human Keratinocytes as Initial Assessment of Pollution Protection

Introduction One of the main functions of cutaneous tissues is to protect our body from the outdoor insults. Ozone (O3) is among the most toxic stressors to which we are continuously exposed and because of its critical location, the skin is one of the most susceptible tissues to the oxidative damaging effect of O3. O3 is not able to penetrate the skin, and although it is not a radical per se, the damage is mainly a consequence of its ability to induce oxidative stress via the formation of lipid peroxidation products. Aim of Study In this study we investigated the protective effect of defined “antioxidant” mixtures against O3 induced oxidative stress damage in human keratinocytes and understand their underlying mechanism of action. Results Results showed that the mixtures tested were able to protect human keratinocytes from O3-induced cytotoxicity, inhibition of cellular proliferation, decrease the formation of HNE protein adducts, ROS, and carbonyls levels. Furthermore, we have observed the decreased activation of the redox sensitive transcription factor NF-kB, which is involved in transcribing pro-inflammatory cytokines and therefore constitutes one of the main players associated with O3 induced skin inflammation. Cells exposed to O3 demonstrated a dose dependent increase in p65 subunit nuclear expression as a marker of NF-kB activation, while pre-treatment with the mixtures abolished NF-kB nuclear translocation. In addition, a significant activation of Nrf2 in keratinocytes treated with the mixtures was also observed. Conclusion Overall this study was able to demonstrate a protective effect of the tested compounds versus O3-induced cell damage in human keratinocytes. Pre-treatment with the tested compounds significantly reduced the oxidative damage induced by O3 exposure and this protective effect was correlated to the abolishment of NF-kB nuclear translocation, as well as activation of Nrf2 nuclear translocation activating the downstream defence enzymes involved in cellular detoxification process.

An evaluation of the effect of a topical product containing C-xyloside and blueberry extract on the appearance of type II diabetic skin

Background  Diabetes is a multisystem disease caused by the presence of chronic hyperglycemia, which leads to increased oxidative stress. Many of the changes observed in type II diabetic patients can be traced to the increased production of advanced glycation end products, also known as AGEs. AGEs are produced as a result of a nonenzymatic reaction with glucose interacting with proteins, lipids, and nucleic acids. AGEs are also present in normal skin with advancing age and contribute to the senescence of many body organs, including the skin.

Clinical tolerance and efficacy of capryloyl salicylic acid peel compared to a glycolic acid peel in subjects with fine lines/wrinkles and hyperpigmented skin

Background  Several chemical agents are currently used to perform superficial peels of the face to reduce facial hyperpigmentation and fine lines/wrinkles. Some of the most commonly used agents are alpha hydroxyl acids, such as glycolic acid (GA), or beta hydroxy acid, such as salicylic acid.

Complementary effects of antioxidants and sunscreens in reducing UV-induced skin damage as demonstrated by skin biomarker expression

Abstract Background: UV-exposure of the skin causes oxidative stress, leading to inflammatory reactions and premature skin aging. Sunscreens protect by absorbing or reflecting UV on the skin surface. Antioxidants provide protection by quenching UV-induced reactive oxygen species inside skin. Objective: To evaluate the complementary photoprotective benefits of formulas containing either an antioxidant complex of Cassia alata leaf extract or a combination of the antioxidant complex and sunscreens on normal healthy volunteers using biomarkers of skin damage. Methods: Each formula and a placebo control were applied separately to selected areas on the lower back of 10 individuals for 4 consecutive days. On Day 4, the control and three test sites were exposed to 5 × MED (minimal erythemal dose) of solar-simulated UV-irradiation (UVR). On Day 5, 4-mm punch biopsies were collected from the four exposed sites and a control site (untreated, unexposed) for immunohistochemistry. Results: Exposure to 5 × MED demonstrated significant damage as assessed by thymine dimer formation, MMP-9 and p53 protein expression on untreated exposed skin. The formula containing sunscreens + the antioxidant complex was the most protective, followed by the formula with the antioxidant alone. Conclusion: The study demonstrated that a combination of antioxidants and sunscreens complement each other, resulting in superior photoprotection.

Dyspigmentation, skin physiology, and a novel approach to skin lightening

Even facial pigmentation is considered a universal sign of youth and beauty in all cultures and at all ages in both men and women. The recent FDA concern about the safety of topical hydroquinone has provided the impetus for research into new pigment lightening alternatives in the cosmetic OTC market.

Enhanced efficacy of a topical antioxidants regimen in conjunction with a home-use non-ablative fractional diode laser in photodamaged facial skin.

Background: Photodamaged facial skin is characterized by fine lines and wrinkles, mottled pigmentation, and other changes. Objective: To evaluate and compare the efficacy and tolerance of a home-use laser device when used alone or in combination with an antioxidant facial treatment for moderate photodamage. Methods: This was a 49-subject, evaluator-blinded, split-face, randomized, single-center, 24-week, phase-2, study. In phase 1, all subjects were treated on one facial side with test products and a home-use laser device and the other side was treated with laser alone for 12 weeks, followed by a 2-week regression period during which they used only support materials. For phase 2, all subjects were divided into 2 independent treatment groups. For the next 10 weeks, subjects of first group treated the assigned facial side with test products and support materials and the other facial side with only support materials. Subjects in the second group treated their entire face with only support materials. Efficacy and tolerance were assessed by clinical grading, VISIA-CR imaging, and self-assessment questionnaires. Results: The combination of laser and test products improved all photodamage parameters evaluated. Conclusion: The test products enhanced and prolonged clinical benefits obtained with the laser alone.

Complementary clinical effects of topical tightening treatment in conjunction with a radiofrequency procedure

Abstract Background: Skin laxity and cellulite on the buttocks and thighs are two common cosmetic concerns. Skin tightening with radiofrequency (RF) devices has become increasingly popular. Objective: The purpose of this study is to evaluate the efficacy and safety of a topical skin laxity tightening agent when used in combination with an RF device. Methods: A double-blinded, randomized clinical trial enrolled twenty females with mild-to-moderate skin laxity on the posterior thighs/buttocks. Each subject underwent two monthly treatments with an RF source (Alma Accent) to both legs. Subjects were then randomized to apply a topical agent (Skinceuticals Body Tightening Concentrate) twice daily to only one designated thigh/buttock throughout the eight-week duration of the study. All subjects were evaluated for improvement in lifting, skin tone, radiance, firmness/tightness, skin texture, and overall appearance based on photographic evaluation by blinded investigators at 12 weeks following the final RF treatment. Results: A statistically significant improvement was found in the overall appearance on both sides treated with the RF device when compared to baseline. However, the area treated with the topical agent showed a statistically significantly greater degree of improvement than the side where no topical agent was applied. No adverse effects were reported. Conclusion: The use of a novel skin tightening agent used after RF procedures is both safe and effective for treatment of skin laxity on the buttocks and thighs. Combined therapy leads to a better result.

Overview of the Structure and Function of Ethnic Skin

Publisher Summary There has been a recent surge of information available about the properties of ethnic skin. There are firm differences in the skin of various ethnic groups. This chapter covers the differences in the structure and function of ethnic skin. The epidermal layer of skin is made up of five different layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. The stratum corneum, the most superficial layer, is the layer responsible for preventing water loss and providing mechanical protection. Melanin is the major determinant of skin color. Melanin absorbs UV light and blocks free radical generation, thus protecting the skin from sun damage and aging. The major differences are as follows: The stratum corneum of black skin is more compact and has greater intercellular adhesion than that of white skin. The epidermis of black skin rarely shows atrophied areas. The stratum lucidum in black skin is not altered by sunlight exposure. Lipid content in black skin is higher that that of white skin. The dermis of white skin is thinner and less compact compared to that of black skin. The number of fibroblasts and lymphatic vessels are greater in black skin. The mast cells of black skin contain larger granules. Skin conductance is higher in blacks and Hispanics than in whites. Despite the recent surge in information regarding the properties of ethnic skin, more studies are necessary for a complete understanding.