Elastin changes during chronological and photo‐ageing: the important role of lysozyme

Abstract

Cutaneous ageing, as a result of combined chronological and photo-ageing in sun-exposed areas, is accompanied by major modifications of the elastic fibres. We aimed to investigate qualitative and quantitative changes of dermal elastin fibres during cutaneous chronological and photo-ageing and the involvement of lysozyme in these processes. Morphological, age-related changes and variations in the relative elastin content in sun-protected (buttock) and sun-exposed (forearm and face) skin of healthy volunteers were studied (145 samples). The deposition of lysozyme in elastin fibres was studied using light and immuno-electron microscopy and taking into consideration the relative efficacy of different UV wavebands (UVA or SSR (solar simulated radiation)). Our studies also included the proteolytic degradation of elastin by human leucocyte elastase (HLE) in situ. Our results indicate a reduction of elastin content with age in sun-protected and sun-exposed skin, associated for the latter with high elastin content, resulting in elastosis. Total UVA (320-400 nm), and in particular long wave UVA (UVA-1, 340-400 nm), induces lysozyme deposition in elastin fibres to a higher extent than solar simulated radiation (SSR, 280-400 nm). Immuno-electron microscopy revealed lysozyme association with the electron-dense granular amorphous elastin structures, corresponding to a basophilic degeneration induced by sun exposure. Lysozyme has no elastolytic activity in situ; however, its binding to elastin limits elastin degradation by human leucocyte elastase (HLE). In addition, a direct inhibitory effect of lysozyme on HLE was observed. Our data suggest that lysozyme prevents elastin degradation by HLE after binding to the damaged parts of the elastin network and by direct lysozyme-HLE interaction, which reduces HLE proteolytic activity. These observations contribute to a better understanding of the chronological and photo-induced changes of the dermal elastic network.

Elastin Accumulation in Actinic Cheilitis with Different Degrees of Epithelial Dysplasia

“…Many immunohistochemical studies have reported an increased deposition of non-functional elastic fibers and a correlation between the stain intensity and the extent of sun damage (Seite et al, 2006;Yano et al). Some authors also associate angiogenesis with the alterations in elastin after UV irradiation, suggesting that angiogenesis induced by UVB mediates the damage caused by UV in the skin (Yano et al, 2005).…”

“…Most of the clinical changes seen with aging result from excessive sun exposure (Seite et al, 2000;Seite et al, 2006). Many immunohistochemical studies have reported an increased deposition of non-functional elastic fibers and a correlation between the stain intensity and the extent of sun damage (Seite et al, 2006;Yano et al).…”

Epidermal growth factor improves the migration and contractility of aged fibroblasts cultured on 3D collagen matrices

“…More specifically, cutaneous aging comprises the loss of elasticity, which causes wrinkling of the skin through the deprivation of extracellular matrix (ECM) (2,3). Treatments for skin aging include herbal extracts, vitamins and growth factors, which have been established to promote ECM protein synthesis and to reduce degradation enzymes of the ECM, thereby delaying the progression of skin aging (4)(5)(6).…”

‘Malignant melanoma microecosystem’: Immunohistopathological insights into the stromal cell phenotype

“…Elastic fibres are coated with distinct molecules following chronic uV exposure (50)(51)(52)(53). The serine anti-leukoprotease elafin, as well as versican and lysozyme, bind to elastin preventing elastolytic degradation by elastases on sun-exposed areas exhibiting solar elastosis (51,53,54).…”