A novel in vivo model for evaluating agents that protect against ultraviolet A-induced photoaging.
Takeuchi T; Uitto J; Bernstein EF
Department of Dermatology, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
J Invest Dermatol (United States) Apr 1998, 110 (4) p343-7
Increasing evidence demonstrates that ultraviolet A radiation (UVA) contributes to photoaging, which results in the accumulation of massive amounts of abnormal elastic material in the dermis of photoaged skin. To study UVA-induced photoaging in an in vivo system, we utilized a line of transgenic mice containing the human elastin promoter linked to a chloramphenicol acetyl transferase reporter gene. Our prior work demonstrates promoter activation in response to ultraviolet B radiation (UVB), UVA, and psoralen plus ultraviolet A radiation in the skin of these mice. The addition of psoralen (8-MOP) prior to administration of UVA results in substantial increases in promoter activation, as compared with UVA alone. To demonstrate the utility of these mice as a model of UVA-induced photodamage, we administered four lotions to the skin of our transgenic mice that included: a sunscreen containing octyl methoxycinnamate and benzophenone-3 with a sun protection factor (SPF) of 15, the UVA filter butyl methoxydibenzoylmethane, the SPF 15 sunscreen and the UVA filter together, and the lotion vehicle alone. Following sunscreen administration, mice received a single psoralen plus ultraviolet A radiation treatment. All sunscreens decreased chloramphenicol acetyl transferase activity with the SPF 15 sunscreen , the UVA filter, and the combination SPF 15 sunscreen and UVA filter, resulting in increasing degrees of protection against psoralen plus ultraviolet A radiation. These results demonstrate that this model functions as a rapid and sensitive model of UVA photodamage for the identification and comparison of compounds that protect against UVA-induced photoaging.
Complications of laser resurfacing. Methods of prevention and management.
Fulton JE Jr
Dermatol Surg (United States) Jan 1998, 24 (1) p91-9
BACKGROUND: Modern skin resurfacing began with wire brush surgery. The short-pulse carbon dioxide (CO2) lasers provide an alternative approach for facial rejuvenation. However, the potential for the same complications exist.
OBJECTIVES: To review the more common complications, the reasons for their development, and their possible avoidance.
METHODS: After pre-op evaluation and skin conditioning, a protocol for resurfacing was followed with standardized settings on the Ultrapulse CO2 laser. On the glabrous skin 300 mJ of energy and 60 W of power were used. On the eyelid skin the settings were reduced to 250 mJ and 50 W. After three passes with the Computer Pattern Generator (CPG), a semi-occlusive dressing was applied for the first 5 days after surgery. Then, a bland petrolatum ointment was applied for an additional 5 days. Finally, a moisturizer with sunscreen or a bleaching cream was used.
RESULTS: It was possible at these energy fluences to avoid excessive collagen denaturation and to facilitate wound healing with occlusive dressing. However, complications still occurred. Examples of these are presented in detail.
CONCLUSION: Complications can be minimized with patient education, using optimal laser settings, applying occlusive dressings, and recognizing pending problems early.
Effectiveness of antioxidants (vitamin C and E) with and without sunscreens as topical photoprotectants.
Darr D; Dunston S; Faust H; Pinnell S
North Carolina Biotechnology Center, Raleigh, N.C., USA.
Acta Derm Venereol (Norway) Jul 1996, 76 (4) p264-8
Considerable interest has been recently generated concerning the use of natural compounds, anti-oxidants in particular, in photoprotection. Two of the best known anti-oxidants are vitamins C and E, both of which have been shown to be somewhat effective in different models of photodamage. Very little has been reported, however, on the effectiveness of a combination of the two (known to be biologically the more relevant situation); nor have there been detailed studies on the ability of these antioxidants to augment commercial sunscreen protection against UV damage. We report that (in swine skin) vitamin C is capable of additive protection against acute UVB damage (sunburn cell formation) when combined with a UVB sunscreen . A combination of both vitamins E and C provided very good protection from a UVB insult, the bulk of the protection attributable to vitamin E. However, vitamin C is significantly better than vitamin E at protecting against a UVA-mediated phototoxic insult in this animal model, while the combination is only slightly more effective than vitamin C alone. When vitamin C or a combination of vitamin C and E is formulated with a commercial UVA sunscreen (oxybenzone), an apparently greater than additive protection is noted against the phototoxic damage. These results confirm the utility of anti-oxidants as photoprotectants but suggest the importance of combining the compounds with known sunscreens to maximize photoprotection.
Synergistic topical photoprotection by a combination of the iron chelator 2-furildioxime and sunscreen.
Bissett DL; McBride JF
Miami Valley Laboratories, Procter & Gamble Company, Cincinnati, OH 45253-8707, USA.
J Am Acad Dermatol (United States) Oct 1996, 35 (4) p546-9
BACKGROUND: Iron is a factor in skin photodamage, apparently by way of its participation in oxygen radical production. Certain topical iron chelators are photoprotective.
OBJECTIVE: Our purpose was to determine the level of topical photoprotection provided by the iron chelator 2-furildioxime (FDO) in combination with sunscreen in short- and long-term photoprotection models.
METHODS: Guinea pigs were treated topically with FDO, sunscreen , and a combination of the two and were then exposed to varying doses of UV radiation to determine the sun protection factor (SPF). Hairless mice were treated topically with FDO, sunscreen , and a combination of the two and then subjected to long-term exposure to a suberythemal dose of UV radiation. The mice were evaluated for skin wrinkling and skin tumors.
RESULTS: In guinea pigs, topical FDO combined with sunscreen provided more than additive protection; 5% FDO alone provides approximately SPF 4, whereas 5% FDO combined with an SPF 4 sunscreen product yielded an SPF of more than 30. In hairless mice exposed long term to UV radiation, 5% FDO and sunscreen delayed tumor onset by a mean of 8 and 12 weeks, respectively. The combination of FDO and sunscreen delayed tumor onset by a mean of 58 weeks. A similar more than additive level of protection was observed for skin wrinkling.
CONCLUSION: Topical FDO combined with sunscreen is a potent photoprotection system against both short- and long-term UV radiation exposure.
A review of skin ageing and its medical therapy.
Department of Dermatology, Boston University School of Medicine, MA 02118, USA.
Br J Dermatol (England) Dec 1996, 135 (6) p867-75
Intrinsic (chronological) skin ageing is characterized by atrophy of the skin with loss of elasticity and slowed metabolic activity. The superposition of environmental damage, particularly exposure to ultraviolet radiation (photodamage), on the intrinsic ageing process results, at least initially, in a hypertrophic repair response, with a thickened epidermis and increased melanogenesis. Even more striking changes occur in the dermis: massive elastosis (deposition of abnormal elastic fibres), collagen degeneration, and twisted, dilated microvasculature. Regular use of a sunscreen alone appears to allow some repair as well as protection from further photodamage. Topical tretinoin has been shown to partially reverse the clinical and histological changes induced by the combination of sunlight exposure and chronological ageing. A formulation of tretinoin in an emollient cream (Retinova, Renova), developed specifically for the treatment of photodamaged skin, has been extensively investigated in multicentre, double-blind trials and has been shown to produce significant improvement within 4-6 months of daily use, compared with vehicle alone, as part of a regimen including sun protection and moisturizer use. Histological changes in the epidermis and dermis noted after 12 months suggest tretinoin repairs photodamage by reconstitution of the rete pegs, repair of keratinocyte ultrastructural damage, more even distribution of melanocytes and melanin pigment, deposition of new papillary dermal collagen, and improvements in vasculature. Alpha-hydroxy acids (AHAs) have also been widely used for therapy of photodamaged skin, and these compounds have been reported to normalize hyperkeratinization and increase viable epidermal thickness and dermal glycosaminoglycans content. The single randomized controlled study now available appears to substantiate AHA efficacy and safety. In summary, recent work has substantially elucidated the ageing processes that affect the skin and has demonstrated that many of the unwanted changes can be improved by topical therapy. (50 Refs.)
Sun exposure and skin disease.
Taylor CR; Sober AJ
Department of Dermatology, Harvard University, Massachusetts General Hospital, Boston 02114, USA.
Annu Rev Med (United States) 1996, 47 p181-91
Sunlight exposure produces a variety of adverse cutaneous effects. Erythema, photosensitivity, and immunologic alterations represent acute events, whereas photoaging and carcinogenesis are long-term consequences. These adverse cutaneous sequelae can be minimized by photoprotection in the form of sun avoidance, regular cover-up with clothing, and sunscreen application. This chapter reviews the diagnosis and treatment of sun-related skin disorders and recommendations for reducing photodamage. (40 Refs.)
Current concepts. Photoprotection.
Department of Dermatology and Cutaneous Surger, University of Miami (Fla), USA.
Arch Fam Med (United States) May 1996, 5 (5) p289-95
Photoprotection encompasses all methods to prevent UV radiation (UVR) damage to the skin, including sunscreens, clothing, seeking shade, and duration and time of the day spent outdoors under UVR. As scientific research validates short- and long-term detrimental effects of UVR, physicians and the public must become increasingly aware of these problems to avoid them. Photoaging is defined. Choice of sunscreens, their Food and Drug Administration labeling, and future sunscreen products are reviewed. Hazards of UVR on the skin include acute sunburn, photocarcinogenesis, immunologic suppression, and photoaging. Distinguishing between UV-A and UV-B damage to the skin is discussed. Education of physicians and their patients is crucial to reduce future photodamage to our population, especially with a reduction of the ozone layer and with patients having more free time. The complete skin examination is emphasized as a method to detect photodamaged skin and give patients insight to provide themselves with future photoprotection. A summary of advice for patients is provided for physicians to give to their patients. (135 Refs.)
The effects of chronic sunscreen use on the histologic changes of dermatoheliosis
Boyd AS; Naylor M; Cameron GS; Pearse AD; Gaskell SA; Neldner KH
Department of Medicine, Vanderbilt University, Nashville, TN 37232-5227, USA.
J Am Acad Dermatol (United States) Dec 1995, 33 (6) p941-6
BACKGROUND: Sunscreen application to the skin of hairless mice is effective in reversing the histologic changes associated with photoaging (solar elastosis, epidermal thickening, collagen depletion, glycosaminoglycan deposition). These reparative processes have not been studied in human beings.
OBJECTIVE: The aim of this study was to evaluate histologically the effects of daily application of a UVA/UVB sunscreen versus placebo.
METHODS: We examined 46 patients who were given either sunscreen or vehicle and asked to apply it daily for 24 months. Punch biopsy specimens were obtained from preauricular skin at 0, 12, and 24 months. Each specimen was examined for epidermal thickening and organization and dermal inflammatory infiltrate by light microscopy. Computer-generated analysis of tissue sections was used to evaluate solar elastosis.
RESULTS: A significant difference in solar elastosis was found between the treatment groups; however, the other features remained largely unchanged.
CONCLUSION: The dermal changes of photoaging may be affected differently than epidermal changes when UV radiation exposure is diminished. UVA and UVB may contribute diversely to these cutaneous changes. Computer-generated evaluation of dermatoheliosis may be more accurate than visual inspection.
Effect of a conjugated oestrogen (Premarin) cream on ageing facial skin. A comparative study with a placebo cream.
Creidi P; Faivre B; Agache P; Richard E; Haudiquet V; Sauvanet JP
Service de Dermatologie I, Centre Hospitalier et Universitaire, Hopital Saint-Jacques, Besancon, France.
Maturitas (Ireland) Oct 1994, 19 (3) p211-23
The effects of Premarin cream on ageing facial skin were studied in a randomised, double-blind, parallel group study. Fifty-four women aged 52-70 years who had moderate to severe facial cutaneous ageing, applied 1 g of either Premarin cream (0.625 mg conjugated oestrogens per gram of cream), or placebo cream (same composition with the exclusion of conjugated oestrogens) to the face nightly for 24 weeks. Each morning these women protected their face with a sunblock SPF 15. Skin thickness was measured by B-scan ultrasonic echography, and skin microrelief by profilometry. Each subject's facial appearance was also evaluated by the subject herself and by the clinician. A statistically significant difference (P = 0.013) in favour of Premarin cream was detected in skin thickness at week 24. Skin thickness (dermal plus epidermal) for the women who used Premarin cream increased from 1.56 +/- 0.20 mm at baseline to 1.68 +/- 0.19 mm, compared with 1.52 +/- 0.20 mm at baseline to 1.59 +/- 0.19 mm in the placebo group. Premarin cream was also significantly more effective than placebo cream in improving fine wrinkles according to the results at weeks 12 and 24 (P = 0.010 and P = 0.012, respectively). Significant improvement from baseline was detected in both groups for roughness, laxity and mottled pigmentation and/or lentigines; however, there was no significant difference in these parameters between the two treatment groups. No subjects discontinued treatment for a safety reason. In conclusion, Premarin cream produced better results than the placebo cream; the difference was statistically significant for skin thickness and fine wrinkles. Premarin cream was well tolerated locally, and its general safety was good.
Sunbathing: college students' knowledge, attitudes, and perceptions of risks.
Vail-Smith K; Felts WM
Health, Physical Education, Recreation, and Safety Program, East Carolina University, Greenville, North Carolina.
J Am Coll Health (United States) Jul 1993, 42 (1) p21-6
This study assessed the knowledge, attitudes, and behaviors of college students regarding intentional sun exposure (sunbathing). Results are based on responses of 296 Caucasian students to the Sun and Skin Inventory. Frequent sunbathers were more likely than infrequent sunbathers to be women and to report fewer self-perceived risk factors, and were less likely to use sunscreen . They were also more likely to believe that they look better with a tan, that suntanned skin is more attractive, and that suntans look healthy. Forty-three percent of the female respondents and 61% of the men rarely, if ever, used sunscreens, and only 9% of all respondents reported they used sunscreens with every intentional sun exposure of 30 minutes or longer. These results suggest that concern with attractiveness appears to be a major motivation for frequent intentional sun exposure. Consequently, educational strategies that stress health outcomes only may be less effective than those that also stress photoaging, the detrimental cumulative effect to appearance of suntanning.
Photoaging and the skin. The effects of tretinoin.
Green LJ; McCormick A; Weinstein GD
Department of Dermatology, University of California, Irvine.
Dermatol Clin (United States) Jan 1993, 11 (1) p97-105
The appearance of photoaged skin is cosmetically unacceptable to many in our society. Ostensibly, avoidance of ultraviolet light and sunlight from early childhood is most desirable but not likely to happen in our culture. Tretinoin is the only pharmacologic compound shown to partially reverse some signs of photoaging. Improvement with tretinoin therapy has been quantified clinically and histologically. A major degree of improvement occurs in 6 to 12 months, and maintenance treatment one to three times per week may continue this response. Tretinoin therapy should optimally be used with daily moisturizer and sunscreen applications. Psychosocial benefits of tretinoin therapy, use of tretinoin for intrinsically aged or non-Caucasian skin, and higher-strength tretinoin therapy for severely photoaged skin need to be further explored. It is possible that some subsets of patients with photoaged skin may respond better than others. (25 Refs.)
In vivo evaluation of photoprotection against chronic ultraviolet-A irradiation by a new sunscreen Mexoryl SX.
Fourtanier A; Labat-Robert J; Kern P; Berrebi C; Gracia AM; Boyer B
L'OREAL, Laboratoire de Recherche Fondamentale, Aulnaysous-bois, France.
Photochem Photobiol (England) Apr 1992, 55 (4) p549-60
In a previous study on the hairless mouse it was shown that sub-erythemal doses of pure UV-A enhanced the numerous changes normally observed during chronological aging. A new sunscreen (a bis-benzylidene campho sulfonic acid derivative) has been synthesized in our research laboratory (lambda max: 345 nm, epsilon: 47,000). Its photoprotective properties against UV-A induced damages were assessed in our mouse model. Three month old albino hairless mice were exposed for 1 y to suberythemal doses (35 J/cm2) of UV-A obtained from a xenon source filtered through a WG 345 filter. One group of animals was exposed untreated, the other received a formulation containing 5% of the sunscreen prior to irradiation. At the end of the study the cutaneous properties of protected mice were compared to those of unprotected animals and to 3 and 15 month old unirradiated controls. We found that the visible changes induced by UV-A irradiation were mainly sagging and wrinkling. Histological and electron microscopic alterations consisted of hyperkeratosis, increased density of elastic fibers with alteration of fiber orientation and increased glycosaminoglycan deposits. Biochemical changes consisted of decreases in total collagen and collagen hydroxylation and increases in both collagen III/I + III ratio and fibronectin biosynthesis. All these changes were reduced or abolished by the sunscreen .
Photoprotective effects of sunscreens in cosmetics on sunburn and Langerhans cell photodamage.
Elmets CA; Vargas A; Oresajo C
Department of Dermatology, Case Western Reserve University, Cleveland, Ohio.
Photodermatol Photoimmunol Photomed (Denmark) Jun 1992, 9 (3) p113-20
It has become common practice to add sunscreening agents of variable potency to cosmetics to protect against the adverse effects of ultraviolet (UV) radiation exposure. The purpose of this study was to determine whether cosmetic preparations containing sunscreening agents protected against the adverse effects of acute UV radiation exposure and, if so, to identify the components responsible for the photoprotective effects. Pretreatment of skin with one such cosmetic product provided complete protection against UV-induced erythema, sunburn cell formation and Langerhans cell damage in volunteers, skin types II and III, whose skin was exposed to a 1.5 minimal erythema dose daily for 4 consecutive days. When individual components of the cosmetic preparation were analyzed for their photoprotective activities, it was found that both the cinnamate and benzophenone sunscreen combination and an extract of baker's yeast present in the preparation had photoprotective properties. These studies indicate that incorporation of photoprotective agents into cosmetic preparations provides a beneficial function and should therefore be encouraged.
Experience with tretinoin therapy in temperate regions.
Caputo R; Monti M; Rigoni C; Pinelli S; Motta S; Barbareschi M
First Department of Dermatology and Paediatric Dermatology, University of Milan, Italy.
Br J Dermatol (England) Sep 1992, 127 Suppl 41 p51-3
In a previously reported study on the anti-photoageing effects of topical tretinoin, the following regimen produced good patient compliance: 0.01% for 1 month, 0.025% for 1 month; and 0.05% for 4 months. The majority of patients (60/89) enrolled in the initial study continued to apply the cream to the face, and a further 140 patients were enrolled for a long-term study (mean duration 2 years). The prolonged study showed that 91.4% of patients used tretinoin in an attempt to slow down skin aging , and 8.6% sought subjective skin benefits. Of the 163 patients who completed the study, 58.8% sought an improvement of wrinkles, 30.1% skin trophism and 14.7% reduced pigmentation. The product was used throughout the year by 66.9% of patients, but 8.0% stopped using it during the summer. A daytime moisturizing cream was required by 77.9% of patients, and 82.8% used a sunscreen in the summer. Tretinoin was applied to other areas of the body by 63.8% of patients.
Facial moisturizers and wrinkles.
Dermatol Nurs (United States) Jun 1992, 4 (3) p205-7
Facial moisturizers are part of the cosmetic category known as skin care products, which also includes other facial products such as astringents, toners, soaps, and bath products. This article describes the composition and pharmaceutics of currently marketed moisturizers, the use of fragrances and preservatives in these products, how cosmetic facial moisturizers work on wrinkles, sunscreen -containing facial moisturizers, and the Food and Drug Administration's record regulating drug claims for anti-wrinkling products.
Sunscreens with low sun protection factor inhibit ultraviolet B and A photoaging in the skin of the hairless albino mouse.
Harrison JA; Walker SL; Plastow SR; Batt MD; Hawk JL; Young AR
Photobiology Unit, United Medical School of Guy's Hospital, University of London, United Kingdom.
Photodermatol Photoimmunol Photomed (Denmark) Feb 1991, 8 (1) p12-20
We examined the chronic effect of long daily suberythemal, fluorescent solar-stimulated radiation (FSSR; ultraviolet B (UVB)+A(UVA)) and UVA alone on female Skh-1 hairless albino mouse skin. Mice were dorsally irradiated 8 h every weekday for 16 weeks with FSSR or UVA, or 32 weeks with UVA alone. Various topical, low concentration, UVB and/or UVA sunscreens were applied before irradiation. Damage was assessed by skin-fold thickness, histology and biochemically by changes in the proportion of type III collagen. All FSSR-exposed mice showed increased skin thickening, elastic fibre hyperplasia, collagen damage and an increased proportion of type III collagen. Application of the UVB sunscreen (2.00%) resulted in marked protection for all nonbiochemical endpoints. There was no obvious advantage of adding 0.75% UVA sunscreen to the UVB sunscreen , but adding 2.00% UVA sunscreen reduced biochemical changes and connective tissue damage. Sixteen weeks of UVA irradiation caused skin thickening and laxity but the histology and biochemistry were indistinguishable from the controls. The mice irradiated with UVA for 32 weeks showed slight elastic fibre hyperplasia and collagen damage histologically, and increased skin thickening and laxity; these changes were unmodified by the 0.75% UVA sunscreen. These mice showed a significant increase in the proportion of type III collagen against which the UVA sunscreen offered protection. Our data suggest that UVA may be important in photoaging and that the use of low sun protection factor UVB+ UVA sunscreens on a day-to-day basis may offer some protection from solar photoaging.
Time-dependent decrease in sunscreen protection against chronic photodamage in UVB-irradiated hairless mouse skin.
Bissett DL; McBride JF; Hannon DP; Patrick LF
Procter and Gamble Co., Miami Valley Laboratories, Cincinnati, OH 45239-8707.
J Photochem Photobiol B (Switzerland) Jun 1991, 9 (3-4) p323-34
To determine the time dependence of sunscreen protection against chronic photodamage in hairless mice, the time was varied (0-8 h) between topical sunscreen treatment and UVB radiation exposure. Sunscreen products with labeled sun protection factor (SPF) values of 2, 4 and 8 were evaluated; these values were verified in a guinea pig model for SPF determinations. When applied immediately prior to UVB radiation exposure, these sunscreen products were very effective in prevention of skin wrinkling and tumor formation. Onset of photodamage was delayed, the delay being greater with higher SPF values. However, the sunscreen actives were rapidly lost from the skin surface, and their protective effect diminished strikingly as the time between treatment and irradiation increased. For daily protection against chronic photodamage, this suggests a need for photoprotectants with greater substantivity to achieve a high level of protection throughout the day.
Sunscreens and the prevention of skin aging.
University of California, Los Angeles School of Medicine.
J Dermatol Surg Oncol (United States) Oct 1990, 16 (10) p936-8
It has been well established in both human and animal skin that ultraviolet radiation from both ultraviolet B (UVB) (290 nm-320 nm) and ultraviolet A (UVA) (320 nm-420 nm) can produce profound changes in the skin that with recurrent exposure, cause it to become what we recognize as photoaged skin. Experimental studies in animals have confirmed that some sunscreen chemicals are capable of providing protection against ultraviolet-induced photoaging. It is presumed that regular use of these effective sunscreens will also reduce skin aging changes in humans. (14 Refs.)
Photosensitivity in the elderly.
Photobiology Unit, St Thomas's Hospital, London, U.K.
Br J Dermatol (England) Apr 1990, 122 Suppl 35 p29-36
Photosensitivity to drugs and chemicals in the elderly is more prevalent due to more frequent use of medications. Phototoxic reactions to common, orally administered drugs such as diuretics, cardiac agents and antidiabetics may occur and the reactions may be remedied by discontinuing drug therapy. Photocontact dermatitis due to the ingredients in sunscreens or other agents, such as perfumes, may also arise. Diagnosis is often confirmed by photopatch testing and subsequent avoidance of these agents leads to gradual resolution. Idiopathic photodermatoses, such as sunlight-induced polymorphic light eruption or solar urticaria, may occur and persist from an early age and, in elderly subjects, they can cause mild to marked disability. The most disturbing disorder of this type is the severe, widespread eczematous chronic actinic dermatitis, which can be difficult to diagnose. Porphyrias, such as variegate porphyria or erythropoietic protoporphyria, may persist from an early age, whereas porphyria cutanea tarda generally begins in later life. Porphyrias all have specific clinical and biochemical features and, apart from variegate porphyria, usually respond well to treatment following diagnosis. Exposure of elderly skin to sunlight may also cause deterioration of many ordinary dermatoses, particularly seborrhoeic eczema, which generally respond to protection from UV exposure and to treatment of the underlying abnormality. Progress in identifying the underlying causes, the availability of increasingly sophisticated diagnostic techniques, and improvements in sunscreen preparations and therapeutic medications will probably significantly reduce abnormal photosensitivity in the elderly in the near future. (44 Refs.)
Senescence and sunscreens
Institute of Dermatology, United Medical School of Guy's Hospital, London, U.K.
Br J Dermatol (England) Apr 1990, 122 Suppl 35 p111-4
The most reliable way to reduce the chronic effects of solar UV radiation is to limit exposure. Animal data using hairless albino mice suggest that the routine use of sunscreens, which usually act as UVB (280-315 nm) filters, may prevent or inhibit skin photocarcinogenesis and photoageing in man. Conditions of chronic use of sunscreens in human skin, however, are not established but it is possible that, under some circumstances, sunscreen use could enhance skin cancer risk. The use of sunscreens may prevent or inhibit both sun-induced cancers and photoageing, but as yet there is no established method of designating the efficacies of sunscreens for the prevention of the chronic effects of solar UV radiation. This is an important research objective. (31 Refs.)
Drug treatment of photoaged skin
Prof. C.E.M. Griffiths, Section of Dermatology, Phase II, Hope Hospital, Eccles Old Road, Salford M6 8HD United Kingdom
Drugs and Aging (New Zealand) 1999, 14/4 (289-301)
Although the prevention of skin aging is a holy grail of the cosmetic and pharmaceutical industries, this venture may be misplaced. The predominant clinical and biochemical features of aged skin are mostly attributable to photoaging rather than chronology. For instance chronic sun exposure is the major determinant of age spots (actinic lentigines) and wrinkles. Surgical approaches to the treatment of photoaging include face-lift, dermabrasion, chemical peeling, collagen and botulinum toxin injections, and laser re-surfacing. These approaches all have benefit and improve the clinical features of facial photoaging. Drug or pharmaceutical prevention and treatment of photoaged skin is still in its infancy. The main pharmaceutical approach to prevention of photoaging lies in the assiduous use of sunscreens. Recent evidence points to the importance of ultraviolet A (UVA) radiation as well as ultraviolet B (UVB) radiation in the aetiology of photoaging and thus the need fur sunscreens that block both UVB and UVA. Drug treatment of photoaged skin can be categorised as antioxidants, alpha-hydroxy acids and topical retinoids. Of these 3 approaches only topical retinoids, particularly tretinoin (all-trans retinoic acid), have a well documented ability to repair photoaged skin at the clinical, histological and molecular level. Furthermore, the use of topical retinoids may actually prevent photoaging. The current interest in pharmaceutical modulation of the photoaging process has attracted considerable research into the mechanisms of photoaging and cutaneous aging. It is likely that treatment for, or prevention of, the chronological aging process may result from such research.
Molecular mechanisms of cutaneous aging: Connective tissue alterations in the dermis
Uitto J.; Bernstein E.F.
Dr. J. Uitto, Dept. of Dermatol./Cutaneous Biolgy, Jefferson Medical College, Bluemle Life Sciences Building, 233 S. 10th Street, Philadelphia, PA 19107-5541 United States
Journal of Investigative Dermatology Symposium Proceedings (United States) 1998, 3/1 (41-44)
Cutaneous aging is a complex biological phenomenon consisting of two distinct components, (a) the intrinsic, genetically determined degenerative aging processes and (b) extrinsic aging due to exposure to the environment, also known as 'photoaging'. These two processes are superimposed in the sun- exposed areas of skin, with profound effects on the biology of cellular and structural elements of the skin. This overview summarizes our current understanding of the mechanisms of innate versus extrinsic aging with emphasis on connective tissue alterations, primarily collagen and the elastic fiber network. We also introduce a novel transgenic mouse model, expressing a human elastin promoter-reporter gene construct, suitable for studies on biology and preventive pharmacology of the cutaneous aging.
The role of cosmetology and the aesthetic within dermatology in Spain
H. Torras, Servei Dermatologia, Hospital Clinic Provincial, Villarroel 170, 08036 Barcelone Spain
Nouvelles Dermatologiques (France) 1998, 17/4 (249-252)
Cosmetology is the science of art of treating and improving the appearance of healthy skin. It is almost as old as humanity. Until a few years ago, dermatology was only concerned with skin pathology. Cosmetology was mostly chemical, it was concerned with the formulation of products for modifying an aesthetic defect or improving the appearance of ski. At that time, communication between dermatology and Cosmetics was quite limited. Today, 'Cosmetic dermatology' is concerned with skin problems that are expression of a skin dysfunction. So who must take care of skin aging caused by the sun protection or seborrheic or dry skin? The logical answer is the dermatologist. During the last 20 years, the number of dermatologists in Spain has doubled, and this is one of the reasons for the increase in cosmetic dermatology prescriptions. In 1973, 'cosmeceuticals' for the skin represented 30% of total OTC products. In 1993 this percentage rose to 64.7% or more than double. The recent evolution of Cosmetic dermatology and the growing interest shown by dermatologists are demonstrated by several facts: - they often prescribe skin care for normal skin, which was rare 20 years ago; - they make a more precise evaluation of skin type; - they are more interested in Cosmetics and skin aging treatments; - there are more prescriptions for 'cosmeceutical lines'. In the future, socioeconomic progress shall increase the development of new products. European countries will show a progressive increase in homogenization, but certain national differences, specific to the culture of each country or region, will remain.
The study on the ultraviolet-B blocking effect of sunscreens in the epidermal Langerhans cells of hairless mice
Won Y.H.; Yoo Y.E.; Lee S.C.; Kim Y.P.; Chun I.K.
Department Dermatology, Chonnam University Medical School,Kwangju 501-757 South Korea
Annals of Dermatology (South Korea) 1995, 7/4 (288-294)
Background: Sunscreens have been used widely to prevent the photosensitive skin diseases, skin cancer, and skin aging . However, no sunscreen blocks all kinds of effects caused by ultraviolet light(UVL), and the effect of sunscreens on the impairment of immune function by UVL irradiation is controversial. Objective: We try to evaluate the efficiency of sunscreens for blocking the depletion of LC induced by UVB irradiation. Method: The ATPase positive LCs were observed in the skin of hairless mice(Hr+/Kud) irradiated by UVB with or without topical application of sunscreens. Two commercially available sunscreens with respective SPF 8 and SPF 30 were applied to the dorsal trunk skin. The mice were irradiated with different increasing doses of UVB at a single time. Results: The ATPase positive LCs in the irradiated dorsal and ear skin were significantly decreased in densities according to the dosage, and apparently revealed a loss of their dendrites, granulation, and clumping from a UVB dose of more than 60mJ/Cmsup 2. With both sunscreen treatment on the dorsal trunk before irradiation, the densities of LCs on the dorsal skin were significantly higher compared to the untreated groups at all ranges of UVB doses in spite of a dose dependent decrease in their density. However there was no significant difference on their preventive effect between both sunscreens(SPF 8 and SPF 30) except at high UVB doses of more than 240 mJ/Cmsup 2. Conclusion: The LC depletion induced by UVB can be partially protected through the topical application of a sunscreen at a UVB dose dependent fashion. However SPF(sun protective factor) dose not appear to be a good indicator for evaluating sunscreens immunologically.
Awarness tophotodamage versus the actual use of sun protection methods by young adults
Harth Y.; Schemer A.; Friedman-Birnbaum R.
Department of Dermatology, Rambam Med. Cter., Faculty Med.,Haifa 31096 Israel
Journal of the European Academy of Dermatology and Venereology (Netherlands) 1995, 4/3 (260-266)
Objective. There is accumulating evidence that in spite of the large campaigns against excessive solar exposure undertaken by dermatologists worldwide, children and adolescents are still spending long periods in the sun, and do not follow the recommended sun protection guidelines. The purpose of the present study was to evaluate sun exposure in a group of young Israeli adults and to compare it to their knowledge and application of the various sun protection methods. Methods. 202 Caucasian volunteers, (mean age 21.4 +/- 2.6), filled out detailed questionnaires on their sun exposure and sun protection habits. Results. More than 80% of our study participants are regularly sun exposed for longer than 2 h per day whereas sunscreens are utilized only by 64.9%. Sunscreen use was significantly more prevalent in females than males (81.3% vs. 46.5%). The majority of sunscreen users and nonusers believed that sunscreen could prevent skin cancer (94.3% and 82.0%, respectively) and that these compounds can slow skin aging (90.8% and 76.4% respectively). The understanding of the meaning of the 'SPF' was significantly higher in the sunscreen users (85%) than in the nonusers (62.0%). The majority of sunscreen users utilized less than 150 ml of the compound per year which is probably an inadequate amount for a year for full body protection. The two most common reasons for-not using sunscreens regularly; were that the application is time consuming, and that sunscreens prevent tanning. Conclusion. Our data reveals a discrepancy between a considerably good understanding of the need for sun protection and the still deficient application of these measures especially in young adult males.