Drying stress and damage processes in human stratum corneum

Levi, Kemal; Weber, Ryan; Q., J.; Dauskardt, Reinhold H.

doi:10.1111/j.1468-2494.2009.00557.x

Cited by 63 publications

(106 citation statements)

References 58 publications

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“…In vivo, the SC may be under considerable tensile stress; drying stress in particular can be significant and lead to damage that disrupts the barrier function (6,15). We used microtension and bulge testing (n = 3 for each condition) to characterize the SC's stiffness, strength, and strain.…”

Section: Resultsmentioning

confidence: 99%

“…1 decreases with UV exposure, leading to an increase in the crack driving force, G. The biaxial stiffness is a more appropriate parameter than the uniaxial stiffness in this instance because the measure of the biaxial stiffness, the bulge test, is performed under conditions that simulate the in vivo environment. For a conservative measure of the crack driving force G, and to enable comparison with the intercellular cohesion, G C , measured at 30% RH, the stiffness was assumed to be constant at 200 MPa, a typical value for the tissue at 30% RH (15). The biaxial drying stress, σ SC , was characterized from the curvature of an elastic substrate onto which the SC has been adhered (15,48).…”

Section: Discussionmentioning

confidence: 99%

“…For a conservative measure of the crack driving force G, and to enable comparison with the intercellular cohesion, G C , measured at 30% RH, the stiffness was assumed to be constant at 200 MPa, a typical value for the tissue at 30% RH (15). The biaxial drying stress, σ SC , was characterized from the curvature of an elastic substrate onto which the SC has been adhered (15,48). The drying stress significantly increased with UV radiation, and the crack driving force, G, scales with the biaxial drying stress, σ SC , to the power of 2 in Eq.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Solar UV radiation reduces the barrier function of human skin

Biniek

Levi

Dauskardt

2012

Proc. Natl. Acad. Sci. U.S.A.

260

219

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The ubiquitous presence of solar UV radiation in human life is essential for vitamin D production but also leads to skin photoaging, damage, and malignancies. Photoaging and skin cancer have been extensively studied, but the effects of UV on the critical mechanical barrier function of the outermost layer of the epidermis, the stratum corneum (SC), are not understood. The SC is the first line of defense against environmental exposures like solar UV radiation, and its effects on UV targets within the SC and subsequent alterations in the mechanical properties and related barrier function are unclear. Alteration of the SC's mechanical properties can lead to severe macroscopic skin damage such as chapping and cracking and associated inflammation, infection, scarring, and abnormal desquamation. Here, we show that UV exposure has dramatic effects on cell cohesion and mechanical integrity that are related to its effects on the SC's intercellular components, including intercellular lipids and corneodesmosomes. We found that, although the keratin-controlled stiffness remained surprisingly constant with UV exposure, the intercellular strength, strain, and cohesion decreased markedly. We further show that solar UV radiation poses a double threat to skin by both increasing the biomechanical driving force for damage while simultaneously decreasing the skin's natural ability to resist, compromising the critical barrier function of the skin.T he stratum corneum (SC), as the outermost layer of the epidermis, is the body's first line of defense against solar UV radiation. Solar UV radiation plays a dual role in human life: it is pivotal for vitamin D production (1) while also a potent and ubiquitous carcinogen responsible for much of the skin cancer in the human population (2). Although progress has been made in understanding the role of UV radiation in causing skin cancer (3), the role of solar UV radiation in altering the mechanical barrier function of the SC remains unknown.The SC provides both critical mechanical protection and a controlled permeable barrier to the external environment. Although the SC is typically a highly efficient barrier, exposure to harsh conditions can alter its function, leading to severe skin damage such as chapping and cracking. Such damage can cause detrimental skin responses including inflammation and infection caused by compromised barrier function, scarring, and abnormal desquamation, and further aggravate the effects of skin disorders such as atopic dermatitis, ichthyosis vulgaris, and chronic xerosis (4-7).UV radiation is divided into three main types based on wavelength: UVC radiation (200-280 nm) is predominately filtered by the ozone layer in the stratosphere, UVB radiation (280-320 nm) is mainly absorbed by the epidermis, and UVA radiation (320-400 nm) penetrates deeper into the dermis but interacts with both the SC and epidermis as well (8) (Fig. 1). The penetration of UV radiation into the skin can initiate detrimental photochemical reactions, causing both acute conditions such as erythem...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Solar UV radiation reduces the barrier function of human skin

Biniek

Levi

Dauskardt

2012

Proc. Natl. Acad. Sci. U.S.A.

260

219

View full text Add to dashboard Cite

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“…Drying stresses have been well characterized as a function of the chemical potential of water in the environment as well as in the presence of molecules that can alter the barrier function of SC [2][3][4][5]. However, many questions remain about how drying stresses relate to the water content of the SC, and more specifically the various states of water within the SC as well as proteins and lipids conformational changes.…”

Section: Introductionmentioning

confidence: 98%

The relationship between water loss, mechanical stress, and molecular structure of human stratum corneum ex vivo

Vyumvuhore

Tfayli

Biniek

et al. 2014

Journal of Biophotonics

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Proper hydration of the stratum corneum (SC) is important for maintaining skin's vital functions. Water loss causes development of drying stresses, which can be perceived as 'tightness', and plays an important role in dry skin damage processes. However, molecular structure modifications arising from water loss and the subsequent development of stress has not been established. We investigated the drying stress mechanism by studying, ex vivo, the behaviors of the SC components during water desorption from initially fully hydrated samples using Raman spectroscopy. Simultaneously, we measure the SC mechanical stress with a substrate curvature instrument. Very good correlations of water loss to the mechanical stress of the stratum corneum were obtained, and the latter was found to depend mainly on the unbound water fraction. In addition to that, the water loss is accompanied with an increase of lipids matrix compactness characterized by lower chain freedom, while protein structure showed an increase in amount of α-helices, a decline in α-sheets, and an increase in folding in the tertiary structure of keratin. The drying process of SC involves a complex interplay of water binding, molecular modifications, and mechanical stress. This article provides a better understanding of the molecular mechanism associated to SC mechanics.

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“…There results indicate an increased hydration of treated normal skin. According to Levi et al (2009), the moisturizing glycerin reduces the drying stress in human stratum corneum [10].…”

Section: Introductionmentioning

confidence: 99%