France) using self-reported questionnaires and noninvasive imaging and biomechanical techniques. While not extensive, their epidemiological data identified that those residing in Brazil had greater accumulated sun exposure, had a greater incidence of skin cancer and were less likely to use cosmetic products than their French counterparts.Reflectance confocal microscopy was used to assess the structure of the skin; compared with photoexposed French facial skin, Brazilian facial skin was more wrinkled and contained an accumulation of disorganized extracellular matrix subjacent to the dermal-epidermal junction; whether in vivo confocal microscopy has sufficient resolution to categorically define this as 'solar elastosis' is a matter for further debate. The authors also examined the skin using a Cutometer â , a device used extensively in the cosmetics industry to assay the biomechanical properties, notably firmness, of skin. The instrument applies negative pressure to the skin surface via a small aperture and in response, the skin is deformed inside the vacuum chamber. [6][7][8] The extent of skin deformation is measured using a laser: the greater the aperture size, the larger the deformation. Mercurio et al. 5 applied negative pressure to the skin via a 2-mm aperture, which is capable of measuring the elasticity of the epidermal component of the skin and includes the dermal-epidermal junction (larger apertures of 6 mm or 8 mm are required in order to incorporate the deeper layers of the dermis in the deformation). The authors report that Brazilian facial and volar forearm skin had lower viscoelasticity than the European group; measurement of stratum corneum water content 7 was again, lower in the South American cohort. Skin pigmentation measurements indicated that all volunteers, regardless of their geographic location, had similar levels of melanin. Taken together, these multiple alterations in skin properties are likely due to a lifetime of accrued photodamage in the Brazilian group, particularly as the volunteers acknowledged increased sun exposure and lower sunscreen usage in early years.Investigative dermatology research has shown the effects of cumulative sun exposure on multiple components of the dermis and the resultant remodelling of this tissue. 1 This study raises a new intriguing questionwhat proportion of changes, particularly physiological changes such as skin firmness, are due to altered epidermal behaviour as opposed to dermal remodelling? Perhaps the way forward is not to focus on specific molecules but to examine skin more holistically, and use a multi-faceted approachhistological analyses, gross tissue mechanics and high-resolution in vivo imaging, 9 to understand skin better.
References1 Naylor EC, Watson REB, Sherratt MJ. Molecular aspects of skin ageing. Maturitas 2011; 69:249-56. 2 Langton AK, Sherratt MJ, Griffiths CEM, Watson REB. A new wrinkle on old skin: the role of elastic fibres in skin ageing. Int J Cosmet Sci 2010; 32:330-9. 3 Yaar M, Gilchrest BA. Photoageing: mechanism, prevention a...