The ultraviolet spectrum is divided into UVA (400–315 nm), UVB (315–290 nm) and UVC (290–200 nm). Almost all of the UVC radiation is absorbed by the earth’s atmosphere and essentially does not reach ground level. Both UVA and UVB contribute to photoaging with UVA probably playing a more substantial role in the aging process. UVA is better able to penetrate into the dermis as a result of its longer wavelength. Additionally, UVA is able to transmit through window glass resulting in sun exposure even while indoors or driving [1].

Reactive oxygen species (ROS) induced by UVA and UVB radiation leads to the activation of matrix metalloproteinases (MMPs), MMP-1, MMP-3 and MMP-9. MMPs cleave specific sites on collagens I and III leading to collagen degradation. Collagen fibers are replaced by abnormal elastin fibers in the dermis (solar elastosis). Although less is known about the effects of UV radiation on the epidermis, there have been reports of epidermal atrophy leading to the obvious appearance of sebaceous glands and telangiectasias even without wrinkling [2].

The effects of UV light vary based on skin phototype; patients with phototypes I and II are at increased risk of developing sun-related skin damage. The regions of the body predominately affected by photoaging are those most exposed to the sun, including the face, neck, upper chest, back, as well as the dorsum of the hands [2]. The clinical characteristics of photoaging in fair-skinned individuals include fine and coarse wrinkles, solar elastosis (thickening and yellowish discoloration of the skin), solar lentigines, and ephelides. Darker skinned patients can also have the previously mentioned findings but tend to present more commonly with seborrheic keratosis and pigmentary alterations [1]. Chronic sun exposure can also result in a leathery appearance to the skin and the development of telangiectasias. The loss of dermal collagen leads to skin fragility, and often patients will present with ecchymoses even after minor trauma—This is referred to as actinic purpura.

As the term implies, photoaging is a direct result of chronic sun exposure. The most important factor in the treatment (and prevention) of photoaging is sun protection. UVB intensity is highest between the hours of 9 am and 3–4 pm. The sun protection factor (SPF) is used to measure a sunscreen’s capacity to block UVB radiation. The SPF implies that sunscreen is applied to the body in an amount equivalent to 2 mg/cm², which is frequently much less than the amount applied by most users. It is recommended that sunscreen with an SPF of at least 30 be applied daily at least 20 min prior to sun exposure. Reapplication of sunscreen is important especially after exercise [2]. A recent in vitro study in France demonstrated that sunscreen protection of cells significantly reduced UVA-induced expression of matrix metalloproteinase-1, -3 and -9, which are the MMPs implicated in the collagen breakdown of photoaging [3].

Retinoids are comprised of synthetic and natural analogs of vitamin A. Retinoids bind to specific nuclear receptors and can modulate the expression of genes involved in cellular growth and differentiation. Tretinion and tazarotene are prescription retinoids that have been shown to improve wrinkling and uneven pigmentation by enhancing collagen synthesis, dispersing melanin and correcting the atypia associated with UV radiation. It takes about 3–6 months of use to see clinical improvement with topical retinoid applications [4]. Side effects such as skin irritation and peeling often occur but usually decrease over continued application.

Laser treatment is another option, and the ablative carbon dioxide (CO₂) laser is the gold standard for photorejuvenation. The CO₂ laser allows for significant skin tightening and wrinkle reduction. However, the ablative treatment often results in a prolonged postoperative course with persistent erythema and pigmentary changes. Newer nonablative laser treatments have been developed to combat these undesirable side effects.

However, laser treatments remain invasive procedures that are not desirable or cost effective for all patients. Other options for the treatment of photoaging skin include botulinum toxin injections, chemical peels, dermabrasion, rhytidectomy, blepharoplasty, and brow lifts. Furthermore, there are an overwhelming number of cosmeceuticals available, which are not regulated by the Food and Drug Administration (FDA) and can be misleading and confusing to patients. These will be the remaining focus of this chapter.

Cosmeceutical is a term coined by Albert Kligman, MD over two decades ago to refer to non-prescription topical products containing biologically-active ingredients designed to improve the function and appearance of the skin. Hydroxy acids (including alpha and beta) are among the most well-known cosmeceuticals and are frequently employed as peels for photodamaged skin as well as for the treatment of acne and rosacea. In addition to hydroxy acids there are a number of cosmeceuticals marketed as agents for the treatment and prevention of photoaging. Many of these products contain antioxidants that confer photoprotection by scavenging free radical oxygen species (ROS) and blocking UV-induced inflammatory pathways.

Vitamin C (ascorbic acid) is a water-soluble vitamin with antioxidant and anti-inflammatory properties found in many fruits and vegetables. In several in vitro and in vivo studies vitamin C has been shown to enhance dermal collagen synthesis and decrease collagen degradation and melanin formation. In a 12-week double-blind, split-face trial, topical application of vitamin C lead to significant improvement in photoaging scores and skin wrinkling. Additionally, histological evaluation of the skin treated with topical vitamin C showed increased collagen production [5]. In a study by Lin et al., a topical solution of 15 % l-ascorbic acid (vitamin C) and 1 % α-tocopherol (vitamin E) was found to be protective against erythema and sun burn cell formation after irradiation [6]. A later study showed that the plant antioxidant ferulic acid improved the chemical stability of the vitamin C and E solution as well as doubled its photoprotection ability [7].

Green tea is produced by steaming and drying the leaves of the tea plant, Camellia sinensis. This process does not require fermentation allowing the preservation of the teas polyphenolic compounds and its potent antioxidant properties. Epigallocathechin-3-gallate is the most abundant polyphenol present in green tea. In a recent study, the application of sunscreens containing 2–5 % green tea extract to human skin significantly reduced the expression of MMP-2 and MMP-9 [8]. In another study, skin biopsies of patients treated with both oral and topical green tea demonstrated significant improvement in elastic tissue content [9].

Pomegranate (Punica granatum) is a tree native to Asia commonly prepared as a juice, concentrate, jam or jelly. Pomegranate contains several polyphenols conferring its potent antioxidant effects [10]. The most abundant polyphenol present in Punica granatum

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