A Short-Term Screening Protocol, Using Fibrillin-1 as a Reporter Molecule, for Photoaging Repair Agents

Abstract

Photoaged skin is characterized by coarse and fine wrinkles. The mechanisms of wrinkle formation are undetermined, but appear to be due to changes within the matrix of the dermis and at the dermal-epidermal junction. Previous studies have identified marked reductions in procollagens I and III, collagen VII, and the fibrillin-rich microfibrillar apparatus in this area. Topically applied all-trans retinoic acid can repair photoaged dermal matrix, but this takes at least 6 mo of treatment. In this study, we have examined the abundance and distribution of fibrillin-1 prior to, and following, 192 wk of all-trans retinoic acid treatment. We have further developed a short-term protocol to determine the utility of potential repair agents, using fibrillin-1 as the marker for outcome. Individuals with clinically assessed severe photoaging were recruited to the study (n = 8). 0.025% all-trans retinoic acid, 5% sodium lauryl sulfate (irritant control), or vehicle were applied under occlusion to photoaged extensor forearm. A fourth control area was also occluded. After 96 h, punch biopsies were taken under local anesthesia and processed for either transmission electron microscopy or snap frozen. Frozen sections were prepared for immunohistochemistry and in situ hybridization immunohistochemistry. Electron microscopy revealed aberrant elastic fibers in the papillary dermis of photoaged forearm skin, with sparse microfibrillar apparatus and interstitial collagen. After application of 0.025% all-trans retinoic acid, there was increased deposition of both these dermal matrix components, with the aberrant elastic fibers no longer apparent. Significant increases (p < 0.05) were observed at the protein and mRNA levels for fibrillin-1 following all-trans retinoic acid and sodium lauryl sulfate treatments, with all-trans retinoic acid having a significantly greater effect than irritant control (p < 0.001); however, neither application had significant effect on the abundance of collagen VII or its mRNA. Investigation of collagen I synthesis revealed no difference following treatments. To ascertain the clinical relevance of using fibrillin-1 as a marker for photoaging, facial skin was biopsied at baseline and after long-term (192 wk) topical all-trans retinoic acid treatment (n = 5). Biopsies were wax-embedded and sections prepared for immunohistochemistry for fibrillin-1. Significant increases in the abundance of the microfibrillar apparatus was observed proximal to the dermal- epidermal junction (p < 0.001) following long-term all-trans retinoic acid application. This study indicates that all-trans retinoic acid can significantly affect fibrillin-1 content in photoaged skin. Furthermore, fibrillin-1 can be used as a "reporter" molecule in short-term protocols for testing the utility of topical agents in the repair of photoaged skin.

Beneficial Regulation of Elastase Activity and Expression of Tissue Inhibitors of Matrixmetalloproteinases, Fibrillin, Transforming Growth Factor-β, and Heat Shock Proteins by P. leucotomos in Nonirradiated or Ultraviolet-Radiated Epidermal Keratinocytes

“…There are three known fibrillin proteins; fibrillin-1 is most abundant in mature tissue and fibrillin-2 is associated with elastin fibers [19,20]. The microfibrils are degraded by proteases or reduced in expression at the epidermal junction and in the elastin fibers with aging or photoaging [4][5][6]. The induction of fibrillin is associated with skin repair, and is a target in the screening for cosmetic products [5,6].…”

“…The microfibrils are degraded by proteases or reduced in expression at the epidermal junction and in the elastin fibers with aging or photoaging [4][5][6]. The induction of fibrillin is associated with skin repair, and is a target in the screening for cosmetic products [5,6]. P. leucotomos extract stimulates the expression of elastin in nonirradiated or UVA or UVB radiated fibroblasts and keratinocytes [2].…”

“…UV radiation causes depletes the fibrillin-rich microfibrils, loss of proper elastin fibers, and their degradation leading to solar elastosis [2]. The stimulation of fibrillin has been used as a marker to screen for photoaging repair agents [4][5][6]. P. leucotomos extract stimulates the expression of elastin in dermal fibroblasts and keratinocytes [3].…”

Tissue elasticity and the ageing elastic fibre

“…In contrast, mildly photoaged skin appears roughened and deeply wrinkled and is characterised histologically by the loss of fibrillin microfibrils (Watson et al 1999) and fibulin (Kadoya et al 2005) from the papillary dermis. In severely photoaged skin, however, abundant deposits of highly disorganised, elastic fibre material are distributed throughout the dermis (Warren et al 1991;Watson et al 2001;Werth et al 1996;Yaar and Gilchrest 2007) Early attempts to quantify the effects of ageing on the mechanical properties of skin were hampered by: the use of terminology which was open to misinterpretation (Doubal and Klemera 2002), the diversity of both mechanical tests (Diridollou et al 1998;Rodrigues 2001) and anatomical sites (Escoffier et al 1989), and most importantly by the heterogeneity and anisotropy of the skin layers themselves (Diridollou et al 1998;Pierard 1999). The mechanical response of skin to the application of tensile and torsional forces and to deformations induced by indentation and suction have all been reported in the literature (see Rodrigues 2001 for an excellent review).…”

Facial laser surgery

“…Sagging occurs due to the loss of skin elasticity, which decreases from an early age [7] . Wrinkles (Figures 1 and 2) appear due to the decrease of procollagens I and III and collagen VII [8] . Fitzpatrick skin phototypes [9] are used to classify the responses to sun exposure by the skin ( Table 2).…”