Topical anti-aging agents: state-of-the-art review

Skin, our first interface to the external environment, is subjected to oxidative stress caused by a variety of factors such as solar ultraviolet, infrared and visible light, environmental pollution, including ozone and particulate matters, and psychological stress. Excessive reactive species, including reactive oxygen species and reactive nitrogen species, exacerbate skin pigmentation and aging, which further lead to skin tone unevenness, pigmentary disorder, skin roughness and wrinkles. Besides these, skin microbiota are also a very important factor ensuring the proper functions of skin. While environmental factors such as UV and pollutants impact skin microbiota compositions, skin dysbiosis results in various skin conditions. In this review, we summarize the generation of oxidative stress from exogenous and endogenous sources. We further introduce current knowledge on the possible roles of oxidative stress in skin pigmentation and aging, specifically with emphasis on oxidative stress and skin pigmentation. Meanwhile, we summarize the science and rationale of using three well-known antioxidants, namely vitamin C, resveratrol and ferulic acid, in the treatment of hyperpigmentation. Finally, we discuss the strategy for preventing oxidative stress-induced skin pigmentation and aging.

Skin aging associated with chromium among rural housewives in northern China

751 A comparative analysis of skin aging-associated secreted proteins (SAASP) produced by dermal fibroblasts from intrinsically versus extrinsically aged human skin

Effects of Pollution on Skin Aging

Skin is the largest organ of the human body and undergoes both intrinsic (chronological) and extrinsic aging. While intrinsic skin aging is driven by genetic and epigenetic factors, extrinsic aging is mediated by external threats such as UV irradiation or fine particular matters, the sum of which is referred to as exposome. The clinical manifestations and biochemical changes are different between intrinsic and extrinsic skin aging, albeit overlapping features exist, eg, increased generation of reactive oxygen species, extracellular matrix degradation, telomere shortening, increased lipid peroxidation, or DNA damage. As skin is a prominent target for many hormones, the molecular and biochemical processes underlying intrinsic and extrinsic skin aging are under tight control of classical neuroendocrine axes. However, skin is also an endocrine organ itself, including the hair follicle, a fully functional neuroendocrine "miniorgan." Here we review pivotal hormones controlling human skin aging focusing on IGF-1, a key fibroblast-derived orchestrator of skin aging, of GH, estrogens, retinoids, and melatonin. The emerging roles of additional endocrine players, ie, α-melanocyte-stimulating hormone, a central player of the hypothalamic-pituitary-adrenal axis; members of the hypothalamic-pituitary-thyroid axis; oxytocin, endocannabinoids, and peroxisome proliferator-activated receptor modulators, are also reviewed. Until now, only a limited number of these hormones, mainly topical retinoids and estrogens, have found their way into clinical practice as anti-skin aging compounds. Further research into the biological properties of endocrine players or its derivatives may offer the development of novel senotherapeutics for the treatment and prevention of skin aging.

Background: The process of skin aging is a complex biological phenomenon consisting of two components, referred to as intrinsic and extrinsic aging, respectively. There are currently several studies that research probiotics as alternative therapeutic options for aging skin. Content: Skin aging in an individual is a combination of intrinsic and extrinsic skin aging. Intrinsic skin aging is a natural process that occurs with age, influenced by ethnicity, gender, gene, hormon, etc, while the extrinsic skin aging is influenced by environmental factors, such as life style, pollution, and especially ultraviolet radiation (photoaging). Probiotics are defined as live microorganisms that when administered in adequate amounts confer a health benefit to the host. Major probiotic mechanisms of action include enhancement of the epithelial barrier, increased adhesion to intestinal mucosa, and concomitant inhibition of pathogen adhesion, competitive exclusion of pathogenic microorganisms, production of anti-microorganism substances and modulation of the immune system. Conclusion: Aging is a natural process that we cannot avoid, so probiotics are an alternative therapy to slow down the skin aging process, both intrinsic and extrinsic. Probiotics can decrease MMP (matrix metalloproteinases) level, which is one of the factors that play a role in skin aging.

Background: Skin, the most visible human entity, quickly displays emotional, physical, and psychological well-being. Research has shown a linear correlation between both types of skin aging within 30–69 years. Thus, the current research study aimed to highlight the use of SCINEXA, the novel skin aging score, in predicting accelerated biological aging. Methodology: This cross-sectional study was conducted in Karachi, Pakistan, from 8th October 2021 to 4th December 2021. Both male and female subjects of age groups from 19 to 69 years were included. A novel skin aging score, 'SCINEXA' (Score of Intrinsic and Extrinsic Skin Aging), was used to assess skin aging. Both extrinsic and intrinsic signs were analyzed in terms of pigmented spots, coarse wrinkles, solar elastosis, telangiectasia, and laxity & seborrheic keratosis, respectively. Results: The SCINEXA score indicated that 91.3% of participants had low aging signs and decreased pigmentation, while 2.9% had relatively high pigmentation on the forehead, cheek, forearm, and back of the hand. Coarse Wrinkles of grade 5 on the forehead were present among 19.7% of individuals, and 20.6% showed the same in the crow feet area. The skin aging symptoms are most significantly associated with age (p<0.05). Conclusion: Accelerated biological aging is not found in the studied population using the SCINEXA tool; therefore, the studied population's skin has been found resilient to photo-aging.

Skin aging is a multifaceted process that involves intrinsic and extrinsic mechanisms that lead to various structural and physiological changes in the skin. Intrinsic aging is associated with programmed aging and cellular senescence, which are caused by endogenous oxidative stress and cellular damage. Extrinsic aging is the result of environmental factors, such as ultraviolet (UV) radiation and pollution, and leads to the production of reactive oxygen species, ultimately causing DNA damage and cellular dysfunction. In aged skin, senescent cells accumulate and contribute to the degradation of the extracellular matrix, which further contributes to the aging process. To combat the symptoms of aging, various topical agents and clinical procedures such as chemical peels, injectables, and energy-based devices have been developed. These procedures address different symptoms of aging, but to devise an effective anti-aging treatment protocol, it is essential to thoroughly understand the mechanisms of skin aging. This review provides an overview of the mechanisms of skin aging and their significance in the development of anti-aging treatments.

The SCINEXA: A novel, validated score to simultaneously assess and differentiate between intrinsic and extrinsic skin ageing

Photoaging

ABSTRACTBackground/AimAging involves a progressive deterioration in physiological functions and increased disease susceptibility, impacting all organs and tissues, especially the skin. Skin aging is driven by intrinsic factors (genetics, cellular metabolism) and extrinsic factors (environment, lifestyle). Understanding these mechanisms is vital for promoting healthy aging and mitigating skin aging effects. This review aims to summarize the key factors influencing skin and intrinsic aging, providing a comprehensive understanding of the underlying mechanisms and contributing elements.MethodsA comprehensive literature review was conducted, focusing on peer‐reviewed journals, clinical studies, and scientific reviews published within the last two decades. The inclusion criteria prioritized studies that addressed intrinsic and extrinsic mechanisms of skin aging. To ensure the relevance and quality of the selected sources, a systematic approach was used to assess study design, sample size, methodology, and the significance of the findings in the context of skin aging.FindingsThe review identifies major internal factors, such as cellular senescence, genetic predisposition, telomere shortening, oxidative stress, hormonal changes, metabolic processes, and immune system decline, as pivotal contributors to intrinsic aging. External factors, including UV radiation, pollution, lifestyle choices (diet, smoking, alcohol consumption, and sleep patterns), and skincare practices, significantly influence extrinsic skin aging. The interplay between these factors accelerates aging processes, leading to various clinical manifestations like wrinkles, loss of skin elasticity, pigmentation changes, and texture alterations.ConclusionA comprehensive understanding of both extrinsic and intrinsic factors contributing to skin aging is essential for developing effective prevention and intervention strategies. The insights gained from this review highlight the importance of a multifaceted approach, incorporating lifestyle modifications, advanced skincare routines, and emerging therapeutic technologies, to mitigate the effects of aging and promote healthier, more resilient skin.

Skin ageing results from both the passage of time and from extrinsic forces, predominantly solar ultraviolet irradiation. Intrinsic ageing is characterized by fine wrinkling and homogenous colour on sun‐protected sites whereas extrinsic ageing is characterized by fine and coarse wrinkling, erythema and dyspigmentation on sun‐exposed sites. Two distinct phenotypes of extrinsic ageing have emerged: atrophic and hypertrophic variants. Tools to measure and quantify skin ageing have been developed and offer therapeutic and research applications. Molecular mechanisms distinguishing intrinsic and extrinsic skin ageing are discussed. The implications of skin ageing are cosmetic, medical and social in nature.

Skin aging is a dynamic process that affects the entire body, marked by molecular and structural changes. Type I collagen is the most abundant structural component and accounts 80% of total collagen in human skin. The amount of proline and hydroxyproline reflect the quantity and quality of the collagen fiber in the extracellular matrix of skin, which is alerted due to accumulated effects of intrinsic and extrinsic aging. Extrinsic aging is driven by ultraviolet radiation-induced reactive oxygen species production that activates the matrix metalloproteinase and disrupts the extracellular matrix of skin dermis, while intrinsic aging is the non-enzymatic process resulting in advanced glycation end products (AGEs). In the presence of pentosidine-AGEs, aging process is accelerated. In vivo Raman spectra of human dermis were collected from forearms of 30 volunteers and were divided into three groups: 10 young adult 25±5years, 10 old adult 65±10years and 10 diabetic old adult 65±10years old male participants. Density functional theory was performed to compute the vibration modes of AGEs, pentosidine, and glucosepane. In vivo confocal Raman spectroscopy detects the specific changes in the proline and hydroxyproline conformation, collagen fiber degradation of type I collagen and AGE protein contribution to specific Raman bands in the aged dermis because of Intrinsic and Extrinsic aging. Statistical t test marked significant differences (P<.01) in Raman peaks of proline and hydroxyproline among young adult, old adult, and diabetic old adult participants at wavenumbers 855, 875, 922, and 938cm-1 . In vivo confocal Raman spectroscopy is a useful tool to detect the AGE markers in the old adult and diabetic old adult male participants, which interacts with the ultraviolet radiations and accelerates the aging process resulting in the extracellular matrix degradation.

Cutaneous aging is a complex biological phenomenon consisting of two components: intrinsic aging and extrinsic aging. Intrinsic aging is also termed true aging which is an inevitable change attributable to the passage of time alone and is manifested primarily by physiologic alterations with subtle but undoubtedly important consequences for both healthy and diseased skin and is largely genetically determined [1]. Extrinsic aging is caused by environmental exposure, primarily to UV light, and more commonly termed photoaging. In sun-exposed areas, photoaging involves changes in cellular biosynthetic activity that lead to gross disorganisation of the dermal matrix [2]. The intrinsic rate of skin aging in any individual can be dramatically influenced by personal and environmental factors, particularly the amount of exposure to ultraviolet light. Photodamage, which considerably accelerates the visible aging of skin, also greatly increases the risk of cutaneous neoplasms. So, the processes of intrinsic and extrinsic aging are superimposed. As the population ages, dermatological focus must shift from ameliorating the cosmetic consequences of skin aging to decreasing the genuine morbidity associated with problems of the aging skin. Therefore, a better understanding of both the intrinsic and extrinsic influences on the aging of the skin, as well as distinguishing the retractable aspects of cutaneous aging (primarily hormonal and lifestyle influences) from the irretractable cutaneous aging (primarily intrinsic aging), is very important to solve the problem of aging [2].

Purpose: The aim of this review is to synthesize current literature regarding skin structure and function, the mechanisms of intrinsic and extrinsic aging, and the potential benefits of physical activity for general health, as well as its specific effects on skin aging. Materials and research methods: The article is based on an analysis of research available on PubMed and Google Scholar. A literature review was conducted using following keywords such as “skin aging”, “skin health”, “intrinsic aging”, “extrinsic aging”, “physical activity”, “health”, “exercise”, and “the impact of physical activity on health”. Results: Skin aging results from both intrinsic factors such as genomic instability, epigenetics, telomere shortening, and mitochondrial dysfunction, and extrinsic factors including UV radiation, pollution, smoking, and poor lifestyle habits. Regular physical activity supports skin health by enhancing circulation, promoting collagen synthesis, reducing oxidative damage, modulating hormones, and improving mitochondrial function. Exercise also indirectly benefits the skin by supporting overall health and reducing lifestyle-related risk factors. Conclusion: Physical activity is a promising non-pharmacological strategy for preserving skin integrity and slowing age-related changes. Its incorporation into preventive dermatological care may complement conventional treatments and promote healthy aging. However, further investigations are required to elucidate the underlying mechanisms by which exercise influences the skin aging process.