Retinoids in aging

A Study of Efficacy and Safety of Ashwagandha (Withania somnifera) Lotion on Facial Skin in Photoaged Healthy Adults

Background Facial skin has an essential cosmetic function in both men and women, and photoaged skin can affect the quality of life in healthy people. Ashwagandha (Withania somnifera) which is also called Indian ginseng has adaptogenic properties and is used in traditional Indian medicine to maintain balance, energize, and rejuvenate. Objective This randomized, double-blind, and placebo-controlled study assessed the efficacy and safety of topical application of lotion containing 8% standardized Ashwagandha root extract on improvement of skin parameters in the photoaged facial skin of healthy subjects. Methods Fifty-six healthy men and women aged between 18 and 60 years with Fitzpatrick phototype III-VI skin grade were randomized to receive the topical application (lotion on facial skin) of either Ashwagandha 8% (AG, n=28), or an identical placebo (PL, n=28) for 60 days. The primary outcome was the change from baseline on day 60 in the scores for global physician assessment scoring for the five dermatological signs (skin wrinkles, pores, hydration/moisture, skin brightness/tone, and pigmentation) on facial skin. Secondary outcomes were changes from baseline in the transepidermal water loss (TEWL), melanin index, hydration, and skin elasticity (R2 ratio). Another efficacy outcome was quality of life using the health-specific Short Form Health Survey-12 (SF-12). Safety was assessed using local reactions and adverse events. Three (1 AG, 2 PL) patients were lost to follow-up and per-protocol (PP) data included 53 patients (27 AG, 26 PL). For measurement data, repeated measures analysis of variance (ANOVA) was used to assess treatment effect at different time periods in the PP dataset (n=53). Two groups were compared for differences using a t-test for continuous data or a Mann-Whitney 'U' test for ordinal data. Adverse events were compared between two groups using the chi-square test. Results Greater reduction (p<0.0001) in total physician assessment scores from baseline to day 60 was observed with AG (-74.69%) compared to PL (-48.68%). There was a greater improvement in TEWL, skin hydration, and skin elasticity (R2 ratio) with AG as compared to placebo (p<0.0001). However, the change in melanin index was similar in the two groups at the end of day 60 (p=0.969). The percentage increase in melanin index from baseline to day 60 in the PP dataset was by -2.82% with AG and -1.78% with PL, whereas the percentage reduction in TEWL from baseline to day 60 in the PP dataset was by -15.12% with AG and -8.34% with PL. Similarly, greater percentage improvements were seen with AG as compared to PL for skin hydration (20.66% with AG and 9.5% with PL) and elasticity was assessed by the R2 ratio (16.34% with AG and 3.73% with PL). Adverse events were comparable in the two groups. Conclusions Topical application of a lotion containing Ashwagandha standardized root extract improves the skin condition and quality of life in photoaged healthy individuals. Further studies with different skin types and standard comparators are warranted to substantiate these claims of benefit.

Synthetic Retinoid Seletinoid G Improves Skin Barrier Function through Wound Healing and Collagen Realignment in Human Skin Equivalents

The outer epidermal skin is a primary barrier that protects the body from extrinsic factors, such as ultraviolet (UV) radiation, chemicals and pollutants. The complete epithelialization of a wound by keratinocytes is essential for restoring the barrier function of the skin. However, age-related alterations predispose the elderly to impaired wound healing. Therefore, wound-healing efficacy could be also considered as a potent function of an anti-aging reagent. Here, we examine the epidermal wound-healing efficacy of the fourth-generation retinoid, seletinoid G, using HaCaT keratinocytes and skin tissues. We found that seletinoid G promoted the proliferation and migration of keratinocytes in scratch assays and time-lapse imaging. It also increased the gene expression levels of several keratinocyte proliferation-regulating factors. In human skin equivalents, seletinoid G accelerated epidermal wound closure, as assessed using optical coherence tomography (OCT) imaging. Moreover, second harmonic generation (SHG) imaging revealed that seletinoid G recovered the reduced dermal collagen deposition seen in ultraviolet B (UVB)-irradiated human skin equivalents. Taken together, these results indicate that seletinoid G protects the skin barrier by accelerating wound healing in the epidermis and by repairing collagen deficiency in the dermis. Thus, seletinoid G could be a potent anti-aging agent for protecting the skin barrier.

Comparative efficacy of two anti-aging products containing retinyl palmitate in healthy human volunteers

BACKGROUND

No study yet described the comparative efficacy of two over-the-counter (OTC) anti-aging products in Asian subjects using the techniques involving analysis of living skin.

AIM

We sought to evaluate the anti-aging efficacy of two commercial formulations containing retinyl palmitate using a high-resolution UVA video camera.

METHOD

Total 11 healthy male volunteers, agreed to participate in this single-blind split-face design study with the mean age of 25.5 years. Every night, volunteers applied one type of cream on the left side and other type of cream on the right side of the face, as directed according to the study design for 60 days. Measurements of the parameters were taken at 0, 1st, 7th, 15th, 30th, and 60th day of study period using noninvasive UVA video camera Visioscan^® VC98. Cream applied on right side of the face labeled as "R" and on the left side as "L."

RESULTS

Sixty-day use of the creams showed significant improvement in SELS parameters of the skin. Percent change in skin wrinkling (SEw) parameter calculated after 60 days was -6.68% after applying cream R and -8.27% after applying cream L.

CONCLUSION

We concluded that constituents in both creams have potentially influenced skin surface parameters, thus indicating that, these creams as a better option to lessen the effects of aging on facial skin on long-term application.

Anti-aging cosmetics: facts and controversies

The authors review ageing in its extrinsic and intrinsic mechanisms, as well as the therapies available for improving its effects, and present some of the facts and controversies related to anti-aging cosmetics.

Topical retinoids in skin ageing: a focused update with reference to sun-induced epidermal vitamin A deficiency

Vitamin A is an important constituent of the epidermis, where it plays a crucial role in epidermal turnover. A deficiency of epidermal vitamin A may be the consequence of nutritional vitamin A deficiency, exposure to sunlight or any UV source, oxidative stress or chronological ageing. As a consequence, any treatment aiming at increasing epidermal vitamin A would exert a protective effect against these deleterious conditions. Retinoids may counteract some deleterious actions of UV radiation by physical and biological mechanisms. Topical natural retinoic acid precursors such as retinaldehyde or retinol are less irritant than acidic retinoids and may prevent epidermal vitamin A deficiency due to nutritional deficiency, exposure to sunlight or any condition leading to free radical production. Retinoids may be combined with other compounds with complementary actions against ageing, nutritional deficiency and cancer, such as antioxidants, to potentiate their beneficial effects in the skin.

Retinoids for prevention and treatment of actinic keratosis

Actinic keratosis is a common cause of dermatological consultations and it presents a strong association with squamous cell carcinoma. Many substances are used for treatment and prevention, such as retinoids. Nevertheless, many studies on retinoids emphasize their application in treating and preventing non melanoma skin cancers. In this article, we reviewed studies about systemic and topical retinoids used with immunocompetent patients and organ transplant recipients with actinic keratosis, as primary or secondary outcomes. The majority of these papers pointed to a reduction in actinic keratosis count after treatment with retinoids. However, studies need to be better-defined in order to address the lack of a standardized dose, the absence of control groups, the low number of patients and short follow-up periods. Blind, randomized and controlled clinical trials with adequate sample sizes, specifically focused on actinic keratosis, are needed to clarify the real benefit of topical and/or oral retinoids. Comparison of efficacy and safety between oral and topical retinoids in the prevention and treatment of non-melanoma skin cancers and actinic keratosis is an essential pre requisite to establish new strategies to control these conditions.

A retinyl palmitate-loaded solid lipid nanoparticle system: effect of surface modification with dicetyl phosphate on skin permeation in vitro and anti-wrinkle effect in vivo

Surface-modified solid lipid nanoparticles (SLNs) containing retinyl palmitate (Rpal) were prepared by the hot-melt method using Gelucire 50/13(®) and Precirol ATO5(®). Dicetyl phosphate (DCP) was added to negatively charge the surfaces of the SLNs and thereby enhance the skin distribution properties of Rpal. In vitro skin permeation and in vivo anti-aging studies were performed using SLNs dispersed in a hydrogel. The SLNs were under 100 nm in size with an even polydispersity index (PDI), and the high absolute zeta-potential value was sufficient to maintain the colloidal stability of the SLNs. DCP-modified negative SLNs (DCPmod-SLNs) enhanced the skin distribution of Rpal 4.8-fold and delivered Rpal to a greater depth than did neutral SLNs. The in vivo anti-wrinkle effect of the DCPmod-SLN formulation was Rpal dose-dependent. However, the anti-wrinkle effects of the DCPmod-SLN formulations were significantly different from that of the negative control and effectively prevented the reduction of elastin and superoxide dismutase by UV irradiation. In conclusion, the DCPmod-SLN system presented is a good candidate for topical Rpal delivery.

Topical retinoids in the management of photodamaged skin: from theory to evidence-based practical approach

Skin, being exposed directly to the environment, represents a unique model for demonstrating the synergistic effects of intrinsic and extrinsic factors on the ageing process. Ultraviolet radiation (UVR) is the major factor among exogenous stressors responsible for premature skin ageing. The problem of skin ageing has captured public attention and has an important social impact. Different therapeutic approaches have been developed to treat cutaneous ageing and to diminish or prevent the negative effects of UVR. Topical retinoids represent an important and powerful class of molecules in the dermatologist's hands for the treatment of photodamaged skin. Since their introduction more than 20 years ago, topical retinoids have shown beneficial efficacy and good safety profiles in the management of photodamaged skin, and as therapeutic anti-ageing agents. This review provides a brief retrospective of the development of topical retinoids in the treatment of photodamaged skin, elucidates their mechanism of action, delineates their use and addresses clinical, pharmaceutical and regulatory issues in connection with their intended use.

Cosmeceuticals: the evidence behind the retinoids

A wide range of cosmeceutical products are available on the market currently, but evidence to support their use is often lacking in the literature. Specifically, there is a substantial amount of evidence supporting the efficacy of tretinoin in photoaging, but the evidence supporting retinoid-based cosmeceuticals remains sparse. The authors review the current data in the literature related to vitamin A-derived cosmeceutical products and conclude that cosmeceuticals containing retinaldehyde have been shown in large randomized, controlled trials to have the most beneficial effect on aging skin.

Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety

Aging of skin is an intricate biological process consisting of two types. While intrinsic or chronological aging is an inevitable process, photoaging involves the premature aging of skin occurring due to cumulative exposure to ultraviolet radiation. Chronological and photoaging both have clinically differentiable manifestations. Various natural and synthetic retinoids have been explored for the treatment of aging and many of them have shown histological and clinical improvement, but most of the studies have been carried out in patients presenting with photoaged skin. Amongst the retinoids, tretinoin possibly is the most potent and certainly the most widely investigated retinoid for photoaging therapy. Although retinoids show promise in the treatment of skin aging, irritant reactions such as burning, scaling or dermatitis associated with retinoid therapy limit their acceptance by patients. This problem is more prominent with tretinoin and tazarotene whereas other retinoids mainly represented by retinaldehyde and retinol are considerably less irritating. In order to minimize these side effects, various novel drug delivery systems have been developed. In particular, nanoparticles have shown a good potential in improving the stability, tolerability and efficacy of retinoids like tretinoin and retinol. However, more elaborate clinical studies are required to confirm their advantage in the delivery of topical retinoids.

Elderly skin and its rejuvenation: products and procedures for the aging skin

In the last few decades, there has been a substantial increase in the population of people over 60 years of age. Most of them maintain a good general health and physical activity and fitness. For these individuals there is a good number of dermatologic procedures, medications, and cosmetics that can be prescribed to improve the aspect of skin aging, providing an improvement in their self-esteem and quality of life as a result of their better look. We will discuss the mechanisms of skin aging, and the procedures and substances used to minimize its deleterious effects, such as sunscreens, estrogens, chemical peels, toxin botulinum, fillers and surgical procedures, among others. The use of makeup and the adverse reactions to cosmetics will also be mentioned.

The role of topical retinoids in the treatment of photoaging

Aging of the skin is a complex biological process which is influenced by the interaction of several intrinsic and extrinsic factors. Intrinsic or chronological aging is an inevitable, genetically programmed process, of unclear underlying mechanism, for which no prevention or effective treatment is currently available. Photoaging refers to the gross and microscopic cutaneous changes that are induced by cumulative exposure to UV radiation and are superimposed on the background of chronological aging. Although primarily an aesthetic problem with significant psychological effects, photoaging constitutes the background for the development of precancerous and cancerous skin lesions.Overwhelming clinical and histological evidence indicate that certain structural changes induced by excessive sun exposure can be reversed, to some extent, by the use of topical retinoids. A number of retinoid compounds, for example tretinoin, isotretinoin, retinaldehyde and tazarotene, have been employed for the treatment of photoaged skin, and demonstrate beneficial clinical and histological effects. Adverse effects have been limited to an irritant reaction of variable intensity presenting with dryness, scaling and erythema. Ongoing research will enhance our understanding of the molecular mechanisms that determine the effects of retinoids on photodamaged skin and contribute to the employment of new, more effective and less irritating retinoid compounds.

The effects of a novel synthetic retinoid, seletinoid G, on the expression of extracellular matrix proteins in aged human skin in vivo

BACKGROUND

Although retinoids have potential efficacy in aged skin, their side effect (skin irritation) remains a clinical problem. We designed a novel synthetic retinoid, seletinoid G, by using computer-aided molecular modeling, and investigated its effects on the expression of extracellular matrix proteins in human skin in vivo.

METHODS

Twenty-three subjects were tested on the buttocks using 4-day occlusive application of seletinoid G and all-trans retinoic acid (tRA). Skin irritation after topical application was quantified by the degree of erythema and cutaneous blood flow. The expression of extracellular matrix proteins and interstitial collagenase (MMP-1) in skin biopsies was investigated by immunohistochemical staining and Western blotting.

RESULTS

The topical application of seletinoid G under occlusion induced no skin irritation in contrast to tRA, which caused severe erythema. The topical treatment with seletinoid G increased the expressions of type I procollagen, tropoelastin, and fibrillin-1, and reduced MMP-1 in old skin in vivo. Seletinoid G was found to inhibit not only the UV-induced decrease of type I procollagen but the UV-induced increase of MMP-1 and c-Jun protein in young skin in vivo.

CONCLUSIONS

Seletinoid G is a novel synthetic retinoid, which has little the side effect of skin irritation after topical application. Seletinoid G can repair altered connective tissue in old skin and inhibit UV-induced collagen deficiency in young skin.

Topical retinoids in the treatment of aging of the skin

Aging of the skin is a complex phenomenon resulting from the interaction of several intrinsic and extrinsic factors [1]. Due to the cosmetic disfigurement it produces and its psychological impact, especially to women, aging of the skin has become an issue of great social significance and concern. Intrinsic aging is an inevitable, genetically programmed process, the underlying mechanisms of which remain largely unknown. No prevention or effective treatment is currently available [1]. Among extrinsic influences (wind, heat, cigarette smoke, chemicals, etc.), ultraviolet radiation appears to be the single most important factor associated with aging of the skin [2]. Photoaging refers to gross and microscopic cutaneous changes induced by cumulative exposure to ultraviolet radiation (UVR). These changes are superimposed on the background of intrinsic aging [2]. Increased recreational sun exposure, including excessive sunbathing, the depletion of stratospheric ozone, the use of UVR in the treatment of various skin diseases, are some of the causes that have led to increased prevalence of photoaging during the last decades. The clinical importance of photoaging lies mostly on the potential for the development of precancerous lesions or skin cancer [3]. In contrast to intrinsic aging, photodamage can be prevented by sun avoidance and proper sun protection [2]. Furthermore, overwhelming clinical and histological evidence indicate that skin changes of photoaging can be reversed by the use of topical retinoids [4].