Photoaging therapy with topical tretinoin: an evidence-based analysis

Skin-derived precursor conditioned medium alleviated photoaging via early activation of TGF-β/Smad signaling pathway by thrombospondin1: In vitro and in vivo studies

Photoaging is one major exogenous factor of skin aging. Efficacy and safety of current anti-photoaging therapies remained to be improved. Our previous studies indicated that skin-derived precursors (SKPs) alleviated photodamage by early activation of TGF-β/Smad signaling pathway via thrombospondin1 (TSP1). However, the research concerning SKP conditioned medium (SKP-CM) has never been reported. In the current study, we aimed to explore the anti-photoaging effects of SKP-CM both in vitro and in vivo, and to elucidate the possible mechanisms. Mouse SKP-CM (mSKP-CM) collection was optimized by a comparative method. The concentration of protein and growth factors in mSKP-CM was detected using BCA protein assay kit and growth factor protein chip. The anti-photoaging effects of mSKP-CM and its regulation of key factors in the TGF-β/Smad signaling pathway were explored using UVA + UVB photoaged mouse fibroblasts (mFBs) and nude mice dorsal skin. The research revealed that mSKP-CM contained significantly higher-concentration of protein and growth factors than mouse mesenchymal stem cell conditioned medium (mDMSC-CM). mSKP-CM alleviated mFBs photoaging by restoring cell viability and relieving senescence and death. ELISA, qRT-PCR, and western blot results implied the potential mechanisms were associated with the early activation of TGF-β/Smad signaling pathway by TSP1. In vivo experiments demonstrated that compared with the topical intradermal mDMSC-CM injection and retinoic acid cream application, the photodamaged mice dorsal skin intradermally injected with mSKP-CM showed significantly better improvement. Consistent with the in vitro results, both western blot and immunohistochemistry results confirmed that protein expression of TSP1, smad2/3, p-smad2/3, TGF-β1, and collagen I increased, and matrix metalloproteinases decreased. In summary, both in vitro and in vivo experiments demonstrated that mSKP-CM alleviated photoaging through an early activation of TGF-β/Smad signaling pathway via TSP1. SKP-CM may serve as a novel and promising cell-free therapeutical approach for anti-photoaging treatment and regenerative medicine.

Trifarotene Reduces Risk for Atrophic Acne Scars: Results from A Phase 4 Controlled Study

BACKGROUND

Atrophic acne scarring often accompanies acne vulgaris. The efficacy of topical retinoids for treatment of acne is well documented; however, evidence for use in atrophic acne scars is limited.

METHODS

In this randomized, split-face, double-blind study, subjects (age: 17-34 years, N = 121) with moderate-to-severe facial acne, with acne scars present, were treated with either trifarotene 50 μg/g or vehicle once daily for 24 weeks. Efficacy was assessed by absolute and percent change from baseline in atrophic acne scar counts, Scar Global assessment (SGA), and IGA success rates as well as acne lesion counts.

RESULTS

At week 24, a statistically significantly greater reduction in the mean absolute change from baseline in the total atrophic scar count was noted in the trifarotene- vs vehicle-treated area (- 5.9 vs - 2.7; p < 0.0001) with differences between sides noted as early as week 2 (- 1.5 vs - 0.7; p = 0.0072). The SGA success rate was higher in the trifarotene side at week 12 (14.9% vs 5.0%, P < 0.05) and improved through week 24 (31.3% vs 8.1%, P < 0.001). Similarly, at week 24, the IGA success rate was higher with trifarotene (63.6% vs 31.3%, P < 0.0001) along with reductions in total (70% vs 45%) and inflammatory (76% vs 48%) lesion counts. The incidence of treatment-emergent adverse events was 5.8% (trifarotene) and 2.5% (vehicle); most common (> 1%) was skin tightness (1.7% vs 0.8%), and all events were mild to moderate in severity.

CONCLUSIONS

Trifarotene was effective and well tolerated in treating moderate-to-severe facial acne and reducing atrophic acne scars, with reduction of total atrophic scar count as early as week 2.

TRIAL REGISTRATION

Clinicaltrials.gov NCT04856904.

One-year longitudinal study of the stratum corneum proteome of retinol and all-trans-retinoic acid treated human skin: an orchestrated molecular event

Topically applied all-trans-retinoic acid (RA) is a gold-standard anti-aging molecule used in dermatology. As its cosmetic counterpart used in anti-aging, Retinol (ROL) is also a known metabolic precursor of RA. Despite this metabolic link, they haven't been compared exhaustively in vivo at a mechanistic level. Therefore, to highlight the effect of a topical application of both molecules on in vivo skin, we undertook a longitudinal 1-year study and performed an untargeted proteomic analysis to get a more holistic view on the underlying biological mechanisms of action. The generation of the temporal proteomics signatures of retinol and all-trans-retinoic acid reveals the impact of these molecules on biological functions related to the aging of skin. New biological functions impacted by retinoids were discovered: glycan metabolism and protein biosynthesis. In addition, the temporal analysis reveals highest modulations at early time points while the physical measures, such as epidermal thickening, was mostly observed at the latest time point, demonstrating a strong time lapse between molecular and morphological impacts. Finally, these global temporal signatures could be used to identify new cosmetic compounds of interest.

Relevant Topical Skin Care Products for Prevention and Treatment of Aging Skin

Options for skin care are varied. New products are introduced constantly and it is important for the practitioner to have an understanding of products that impart beneficial results for aging skin. Educating patients to use products with scientifically proven benefits leads to better outcomes. Patients should be encouraged to use daily sunscreen, a topical retinoid every night, and a topical antioxidant daily. Supplementing the routine skin care regimen with alpha hydroxy acids, growth factors, heparin sulfate, and defensins can be addressed individually. Exogenous stem cells do not have sufficient evidence to warrant recommending them currently.

Prevention and Reduction of Atrophic Acne Scars with Adapalene 0.3%/Benzoyl Peroxide 2.5% Gel in Subjects with Moderate or Severe Facial Acne: Results of a 6-Month Randomized, Vehicle-Controlled Trial Using Intra-Individual Comparison

BACKGROUND

Very few clinical trials have investigated the effect of topical acne treatment on scarring.

OBJECTIVES

Our objective was to evaluate the efficacy of adapalene 0.3%/benzoyl peroxide 2.5% gel (A0.3/BPO2.5) in atrophic acne scar formation in patients with acne.

METHODS

In this multicenter, randomized, investigator-blinded, vehicle-controlled study, subjects with moderate or severe facial acne (Investigator's Global Assessment [IGA] score 3 or 4; ≥ 25 inflammatory lesions; ten or more atrophic acne scars) applied A0.3/BPO2.5 or vehicle daily per half face for 24 weeks. Subjects with acne requiring systemic treatment were excluded. Assessments included investigator atrophic acne scar count, Scar Global Assessment (SGA), acne lesion count, IGA, skin roughness and skin texture, subject self-assessment of clinical acne-related scars and satisfaction questionnaire, tolerability, and safety.

RESULTS

Included subjects (n = 67) had mainly moderate acne (92.5% IGA 3); mean scores at baseline were approximately 40 acne lesions and 12 scars per half face. By week 24, the change from baseline in total scar count was - 15.5% for A0.3/BPO2.5 versus  + 14.4% for vehicle (approximately 30% difference), with a mean of 9.5 scars versus 13.3 per half face, respectively (p < 0.0001). For SGA at week 24, a total of 32.9% with A0.3/BPO2.5 versus 16.4% with vehicle (p < 0.01) were clear/almost clear. Inflammatory acne lesions decreased by 86.7% for A0.3/BPO2.5 versus 57.9% for vehicle (p < 0.0001), and 64.2 versus 19.4% of subjects, respectively, were IGA clear/almost clear (p < 0.0001) at week 24. Treatment-related AEs were reported by 20.9% for A0.3/BPO2.5 versus 9% for vehicle side, most commonly skin irritation (14.9 vs. 6%, respectively).

CONCLUSIONS

Topical A0.3/BPO2.5 prevented and reduced atrophic scar formation. Scar count increased with vehicle (+ 14.4%) but decreased with A0.3/BPO2.5 (- 15.5%) over 24 weeks.

TRIAL REGISTRY

ClinicalTrials.gov identifier NCT02735421.

Adapalene 0.3% Gel Shows Efficacy for the Treatment of Atrophic Acne Scars

Introduction

Scarring is an unfortunate clinical outcome of acne. Current treatment options for atrophic acne scars are dominated by non-pharmacological, invasive procedures which may not be suitable or affordable to all patients. This phase II, single-center, open-label, exploratory study assessed the efficacy, safety and subject-reported outcomes of adapalene 0.3% gel in the treatment of atrophic acne scars.

Methods

The study included subjects aged 18–50 years with past history of acne and moderate to severe facial atrophic acne scars. Subjects received adapalene 0.3% gel once daily for the first 4 weeks and twice daily for the following 20 weeks. Assessments were performed at baseline, day 10 and weeks 4, 8, 16 and 24, and at post-treatment follow-ups (weeks 36 and 48–72).

Results

At week 24, investigator and subject assessments reported improvement in skin texture/atrophic scars in 50% and > 80% of subjects, respectively. Subjects were satisfied with the treatment and reported improvements in quality of life.

Conclusion

Daily use of adapalene 0.3% gel for the treatment of atrophic acne scars showed promising clinical efficacy, a favorable tolerability profile, and improvement in quality of life.

Funding

Nestlé Skin Health–Galderma R&D.

Trial Registration

ClinicalTrials.gov Identifier NCT01213199.

Insights on Localized and Systemic Delivery of Redox-Based Therapeutics

Reactive oxygen and nitrogen species are indispensable in cellular physiology and signaling. Overproduction of these reactive species or failure to maintain their levels within the physiological range results in cellular redox dysfunction, often termed cellular oxidative stress. Redox dysfunction in turn is at the molecular basis of disease etiology and progression. Accordingly, antioxidant intervention to restore redox homeostasis has been pursued as a therapeutic strategy for cardiovascular disease, cancer, and neurodegenerative disorders among many others. Despite preliminary success in cellular and animal models, redox-based interventions have virtually been ineffective in clinical trials. We propose the fundamental reason for their failure is a flawed delivery approach. Namely, systemic delivery for a geographically local disease limits the effectiveness of the antioxidant. We take a critical look at the literature and evaluate successful and unsuccessful approaches to translation of redox intervention to the clinical arena, including dose, patient selection, and delivery approach. We argue that when interpreting a failed antioxidant-based clinical trial, it is crucial to take into account these variables and importantly, whether the drug had an effect on the redox status. Finally, we propose that local and targeted delivery hold promise to translate redox-based therapies from the bench to the bedside.

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-photoageing and anti-melanogenesis activities of chrysin

CONTEXT

Melanin plays an important role in preventing skin photoageing by blocking ultraviolet B (UVB). However, East Asian women prefer light and fair skin, therefore they want to keep their skin from photoageing and at the same time reduce the melanin in their skin. Chrysin is a kind of natural flavonoid with luxurious biological activities, which has a very promising effect on achieving this goal.

OBJECTIVE

To elucidate the effects and mechanisms of chrysin on photoageing and melanogenesis.

MATERIALS AND METHODS

Human dermal fibroblasts (HDF) and B16 murine melanoma cells were incubated with chrysin (0-25 μM) for 48 h. Anti-photoageing activity was examined in HDF by assessment of synthesis/degradation of collagen I, antioxidative and antisenescent activities through ELISA and colorimetric method. Anti-melanogenesis activity was tested by assessment of melanin, tyrosinase (TYR), melanogenic proteins inhibition activities in B16 cells using colorimetric and ELISA method.

RESULTS

Chrysin increased collagen I secretion (50-121.54% at 6.25-25 μM) and chrysin showed anti-photoageing activity by decreasing the degradation of collagen I, repairing oxidation damage and reducing the rate of HDF senescence. Furthermore, chrysin exhibited inhibitory activities with 3.00-20.35% reduction of melanin content at 6.25-25 μM, and inhibited melanin synthesis through the inhibition of TYR activity and the suppression of melanogenic proteins (TYR, TYR-related protein-1/2 and microphthalmia-associated transcription factor) expressions.

DISCUSSION AND CONCLUSION

Chrysin may have potential for developing a functional cosmetic agent because of its anti-photoageing and anti-melanogenesis activities.

Effects of topicals on the aging skin process

This article summarizes the antiaging properties of retinoids, glycolic acid, ascorbic acid, and peptide topicals. The supporting evidence is taken from the literature and the primary author's research, consisting of previously published data and new results from ongoing projects.

Alstonia scholaris R. Br. Significantly Inhibits Retinoid-Induced Skin Irritation In Vitro and In Vivo

Topical retinoids inhibit matrix metalloproteinases and accelerate collagen synthesis, thereby triggering antiaging effects in the skin. However, topical retinoids can cause severe skin reactions, including scaling, erythema, papules, and inflammation. The present study demonstrates that the ethanolic bark extract of Alstonia scholaris R. Br. can significantly inhibit all-trans retinoic acid-induced inflammation in human HaCat keratinocyte cells. Furthermore, two representative retinoid-induced proinflammatory cytokines, monocyte chemoattractant protein-1 and interleukin-8, were significantly suppressed by A. scholaris extract (by 82.1% and 26.3% at 100 ppm, and dose-dependently across the tested concentrations) in vitro. In a cumulative irritation patch test, A. scholaris extract decreased retinol-induced skin irritation, while strengthening the ability of retinoids to inhibit matrix metalloproteinase-1 expression, which is strongly associated with aging effects. These results suggest that A. scholaris is a promising compound that may increase the antiaging function of retinoids while reducing their ability to cause skin irritation.

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.

Novel vitamin and gold-loaded nanofiber facial mask for topical delivery

L-ascorbic acid has been widely used in cosmetic and dermatological products because of its ability to scavenge free radicals and destroy oxidizing agents. However, it is chemically unstable and can easily be oxidized. The current cosmetic facial masks available in the market are pre-moistened, which means that the aqueous fluid content of the mask may oxidize some of the unstable active ingredients such as ascorbic acid. This work presents an anti-wrinkle nanofiber face mask containing ascorbic acid, retinoic acid, gold nanoparticles, and collagen. This novel face mask will only be wetted when applied to the skin, thus enhancing product stability. Once moistened, the content of the mask will gradually dissolve and release the active ingredients and ensure maximum skin penetration. The high surface area-to-volume ratio of the nanofiber mask will ensure maximum contact with the skin surface and help to enhance the skin permeation to restore its healthy appearance. Electrospun fiber mats may provide an attractive alternative to the commercial facial cotton masks.

Effect of topical tretinoin on photoaged facial skin: a histometric, immunohistochemical and ultrastructural study

BACKGROUND

Topical tretinoin is a recognized treatment for photoageing.

AIM

To evaluate the microscopic changes induced by topical tretinoin used to treat mild to moderate photodamage in dark-skinned patients aged 30 to 50 years.

PATIENTS AND METHODS

Biopsy specimens were obtained from the facial skin of 11 patients before and after treatment with topical tretinoin. Routine histopathology coupled with histometric computer-assisted image analysis was used to assess epidermal changes. Alcian blue stain was used to measure changes in glycosaminoglycans (GAGs). Immunoperoxidase technique for type I and III collagens and elastin, as well as transmission electron microscopy, were used to measure changes in collagen and elastic fibres.

RESULTS

Epidermal hyperplasia occurs following tretinoin application, which is reversible with continued therapy. GAGs decreased (p < 0.05) after 6 months of tretinoin application but with no significant change thereafter. Quantitatively, there was an insignificant decrease of type I (p = 0.7) and III (p = 0.3) collagens during the first 6 months of tretinoin usage. However, biopsies taken after 10 months revealed a statistically significant increase in collagen I from a mean of 75.2% +/- 9.6 before treatment to 94.2% +/- 4.1 after treatment (p = 0.05). Similarly, the amount of type III collagen increased from a mean of 74.6% +/- 9.96 to 90.6% +/- 2.1 after 10 months of treatment (p = 0.05). On the other hand, the amount of elastin significantly (p = 0.02) decreased from a mean of 54.5% +/- 3.68 before treatment to 43.4% +/- 4.42 after 6 months of tretinoin application but with no significant change thereafter. Such changes were associated ultrastructurally with new collagen deposition and improvement of the quality of elastic fibres.

CONCLUSION

Topical tretinoin benefits facial skin, mainly by increasing collagen I and III and also by improving the morphological appearance of collagen and elastic fibres.

Cosmeceuticals vitamins

The term cosmeceutical was created over 25 years ago to define products with active substances that cannot be considered cosmetics or drugs. Cosmeceuticals are increasingly popular, with sales representing one of the largest growing segments of the skin care market. These products are found in many forms, including vitamins, peptides, growth factors, and botanical extracts. Cosmeceuticals that contain topically applied vitamins have an increasing role in skin care.

Use of oral isotretinoin in photoaging therapy

BACKGROUND

Many drugs are being used for prevention and treatment of photoaging, especially topical retinoids. The use of systemic retinoids, more specifically, isotretinoin, for this purpose has not been properly addressed to date. Our study was designed to assess the systemic use of isotretinoin used alone for the therapy of cutaneous photoaging.

OBJECTIVE

To demonstrate that isotretinoin is converted into retinoid and improves the appearance of the photoaged skin.

METHODS

Fifty women aged 40 to 60 years, phototype I, II, or III according Fitzpatrick, were selected to receive 20 mg of isotretinoin orally 3 times a week for a 3-month period. Patients underwent clinical and laboratory evaluation. Two biopsies and photographic control were performed. Patients were requested to use only topical photoprotecting agents during the treatment. Improvement in photoaging clinical parameters were evaluated through pictures taken and also through an evaluation form. Anatomopathologic parameters were obtained by comparing collagen degeneration and skin trophism. Results. Thirty patients fully complied with study requirements and were adequately analyzed. From the anatomopathologic data, an improvement of photoaging in 20 patients was observed.

CONCLUSIONS

Isotretinoin improves photoaging with few adverse events because of the low dose used and to the short treatment duration.

Role of novel delivery systems in developing topical antioxidants as therapeutics to combat photoageing

Ageing proceeds by highly complicated biochemical processes, in which the involvement of the reactive oxygen species (ROS) and free radicals has been implicated. Reactive oxygen species are dramatically enhanced by exposure to the ultraviolet radiation. Free radical scavengers and antioxidants can thus provide a long-term protection against these changes. Currently, dermaceutical and cosmetic industry is growing immensely with its main focus on packaging the active into a suitable/novel delivery system. This not only enhances the customer acceptance but offers better targeting to the upper skin layer, with faster onset, at a lower concentration of the active. Later also counter toxic or adverse effects observed with large doses especially when administered orally. Several of the antioxidant molecules are labile to degradation in the presence of oxygen, water and light, hence it becomes all the more appropriate to use a delivery system which will augment their stability and hence enhance the performance. In the present review, we focus on the pioneering research on novel delivery systems which can promote the therapeutic value of antioxidants for combating UV-induced photoageing.

Retinoid therapy of pigmentary disorders

Topical retinoids such as all-trans-retinoic acid (RA), 13-cis-retinoic acid (isotretinoin), retinol, retinaldehyde, tazarotene, and adapalene have been shown to improve dyspigmentation of photodamaged skin including mottling and actinic lentigines. RA monotherapy has also been demonstrated to improve melasma and postinflammatory hypermelanosis. Furthermore, RA in combination with hydroquinone or 4-hydroxyanisole, or azelaic acid increases the potency of depigmenting agents for the treatment of melasma, actinic lentigines, and postinflammatory hypermelanosis. The basic mechanisms underlying these effects are not completely identified. Topical retinoids stimulate the cell turn-over of epidermal keratinocytes and promote a decrease in melanosome transfer and a rapid loss of melanins via epidermopoiesis. Topical retinoids are also involved in the control of cell differentiation. Retinoid-induced changes in the stratum corneum and the permeability barrier may also facilitate the penetration of depigmenting agents in the epidermis and increase their bioavailability, leading to increased depigmentation. In addition, several in vitro studies demonstrate that cis and trans-retinoic acid inhibit UV-B stimulated melanogenesis in term of tyrosinase activity and melanin synthesis. It is likely that topical retinoids modulate epidermal melanin count via a direct action on melanocytes and epidermal keratinocytes.

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.

Acitretin and skin cancer in kidney transplanted patients. Clinical and histological evaluation and immunohistochemical analysis of lymphocytes, natural killer cells and Langerhans' cells in sun exposed and sun protected skin

BACKGROUND

Renal transplanted recipients have an increased incidence of actinic keratosis and skin cancer.

METHODS

In order to examine the chemoprophylatic effects of low-dose acitretin on keratosis and skin cancer development we submitted 13 renal transplanted patients who presented actinic keratosis to acitretin therapy (20 mg/d) for 12 months. The patients were assessed at monthly intervals during the first 6 months and every 2 months until the 12th month for new skin lesions and for acitretin toxicity. Normal skin biopsies of sun exposed and sun protected areas were taken for histopathological examination and submitted to immunohistochemistry technique to demonstrate CD4+ and CD8+ T lymphocytes, natural killer (NK) cells and Langerhans' cells which were counted and compared before, after 6 and 12 months of the treatment.

RESULTS

There was an improvement of actinic keratosis in all patients. Only one patient developed new skin cancer. Side-effects were well tolerated and no significant biochemical effects were observed. There were no differences in the microscopic aspects of the skin and in the number of CD4+ and CD8+ T lymphocytes and NK cells. There was a significant increase in the number of epidermal Langerhans' cells after 12 months of acitretin therapy.

CONCLUSIONS

The data obtained permit us to conclude that low dose acitretin therapy is safe, well tolerated and partially effective in chemoprophylaxis of skin cancer in renal transplant recipients. The increase in epidermal Langerhans' cells observed may be an expression of the immunomodulatory effect of acitretin.

Nonablative laser and light treatments: histology and tissue effects--a review

BACKGROUND AND OBJECTIVES

Nonablative laser and light treatments have largely replaced ablative laser therapy in clinical use for the improvement of the visible signs of cutaneous photoaging, including rhytides, vascular lesions, and pigmentation. However, the mechanisms underlying the reported clinical efficacy of nonablative treatments are not well-understood. The purpose of this analysis is to critically evaluate what is known about histologic and tissue effects of nonablative laser therapy and suggest future directions for research.

STUDY DESIGN/MATERIALS AND METHODS

This is a review of the English language literature pertaining to nonablative laser and light treatments available through MEDline (1995-2002), and unpublished reports presented at major national meetings. Only studies that included harvesting and analysis of tissue samples are included.

RESULTS AND CONCLUSIONS

(a) Thermal injury to the dermis in association with epidermal cooling most likely affects the dermal vasculature, which initiates a cascade of inflammatory events that includes fibroblastic proliferation and apparent up-regulation of collagen expression; (b) There is no indication that nonablative treatments are harmful or able to induce skin cancer; (c) It is possible that the horizontally distributed collagen reported after nonablative treatments is a "microscar," an enlarged Grenz sone associated with repetitive photo-induced trauma; (d) Further research is needed to elucidate the biophysical mechanisms underlying nonablative treatment, as well as to distinguish the utility of different wavelengths on epidermal and dermal improvement.

Effect of smoking and sun on the aging skin

Smoking and ultraviolet radiation are known to have a detrimental effect on human skin. Important characteristics of the aging skin are elastosis and telangiectasia. The purpose of the study was to assess the relative importance of age per se, and the detrimental effects caused by sun exposure and smoking on the development of cutaneous elastosis and telangiectasia in a well-defined group of individuals. We made use of 966 individuals who participated in a case-control study to investigate environmental and genetic risk factors for skin cancer. Exposure measurements for sunlight and smoking were collected and the amount of elastosis and telangiectasia in the face and neck was recorded according to a four-graded score varying from none to severe. Relative risks were estimated using exposure odds ratios from cross-tabulation and logistic regression. Multivariate logistic regression was used to adjust for potential confounders. Among both sexes a strong association was observed between increasing age, sun exposure, and amount of elastosis. The association between increasing age, sun exposure, and amount of telangiectasia was strong among men, but less apparent among women. Smoking was also associated with elastosis among both sexes, and with telangiectasia predominantly among men. Intrinsic differences between men and women (e.g., hormones) or behavior differences (e.g., more frequent use of creams and cosmetics among women) could account for this apparent difference in the occurrence of telangiectasia. In contrast to elastosis, telangiectasia may not be a good marker of the aging skin, specifically not in women.

Topical revitalization of body skin

Topical treatments for the body are beneficial for photoageing as well as for specific disease processes, such as scars or striae. Every patient should topically apply photoprotectants in order to prevent photodamage to the skin. Tretinoin can improve body skin and has a documented use in striae. Alpha-hydroxy acids can restore body skin when used on a regular basis. Antioxidants may be of benefit. Scars can be improved with a variety of topically applied agents ranging from silicone gel sheeting to super-potent topical steroids. Chemical peeling for the body can improve the skin with the use of alpha- or beta-hydroxy acids. While topical therapy can improve body skin, adjunctive surgical therapy may be needed to correct body skin disorders or concerns fully.

New and emerging treatments for photoaging

It is easy to become too busy treating the sequelae of photoaging, actinic keratoses, and skin cancers to discuss prevention adequately with patients. With children, sun-protective measures and sunscreen information should be the main therapeutic intervention. In any young adult with an actinic keratosis or skin cancer, topical and resurfacing treatments should be considered. In older patients with fragile skin and solar purpura, reversal of photodamage can have a positive effect on daily functioning.

An extract of Polypodium leucotomos appears to minimize certain photoaging changes in a hairless albino mouse animal model. A pilot study

Chronic ultraviolet B (UVB) exposure of human or murine skin is known to induce cutaneous photoaging and enhanced carcinogenic risk. An extract of Polypodium leucotomos (PL), a tropical fern plant, has been known to exhibit interesting antioxidant and photoprotective properties against acute exposure to ultraviolet radiation. The objective of this preliminary (or pilot) study was to determine the photoprotective role of topically applied Polypodium leucotomos extract in the prevention or amelioration of cutaneous changes of photoaging in hairless mice. PL-treated mice showed significant reduction of skinfold thickness than those observed in PL-untreated controls. Additionally, PL-treated mice showed a significantly lower degree of histologic parameters of photoaging damage, including dermal elastosis, compared with positive control mice. Interestingly, PL treatment also showed reduction in the number of mice showing skin tumors at 8 weeks after the cessation of the UVB exposure protocol. The results of this preliminary study illustrate that PL treatment helped to ameliorate and to partially inhibit some of the histologic damage associated with photoaging of skin and appeared to contribute to a decrease in the prevalence of UVB-induced skin tumors in mice.