A proton NMR study on the hydration of normal <i>versus</i> psoriatic stratum corneum: linking distinguishable reservoirs to anatomical structures

Laule, Cornelia; Tahir, Sumia; Chia, C.L.L.; Vavasour, Irene M.; Kitson, Neil; MacKay, Alex L.

doi:10.1002/nbm.1547

Cited by 6 publications

(7 citation statements)

References 42 publications

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“…5 A), suggesting that the molecular dynamics is, in general, characterized by faster reorientation and/or lower anisotropy at a w ¼ 0.992. This is in agreement with proton NMR studies on the SC, showing a gradual increase in the mobile components of the SC upon hydration (50,51). It is noteworthy that the relative intensity ratio of the CP and DP signals from the main methylene peak at 33.4 ppm is lower at a w ¼ 0.992, implying that the rigidity of the lipids decreases upon hydration.…”

Section: The Effect Of Hydration On the Molecular Mobility Of Sc Components As Observed By Pt Ssnmrsupporting

confidence: 89%

Skin Membrane Electrical Impedance Properties under the Influence of a Varying Water Gradient

Björklund

Ruzgas

Nowacka

et al. 2013

Biophysical Journal

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The stratum corneum (SC) is an effective permeability barrier. One strategy to increase drug delivery across skin is to increase the hydration. A detailed description of how hydration affects skin permeability requires characterization of both macroscopic and molecular properties and how they respond to hydration. We explore this issue by performing impedance experiments on excised skin membranes in the frequency range 1 Hz to 0.2 MHz under the influence of a varying gradient in water activity (aw). Hydration/dehydration induces reversible changes of membrane resistance and effective capacitance. On average, the membrane resistance is 14 times lower and the effective capacitance is 1.5 times higher when the outermost SC membrane is exposed to hydrating conditions (aw = 0.992), as compared to the case of more dehydrating conditions (aw = 0.826). Molecular insight into the hydration effects on the SC components is provided by natural-abundance (13)C polarization transfer solid-state NMR and x-ray diffraction under similar hydration conditions. Hydration has a significant effect on the dynamics of the keratin filament terminals and increases the interchain spacing of the filaments. The SC lipids are organized into lamellar structures with ∼ 12.6 nm spacing and hexagonal hydrocarbon chain packing with mainly all-trans configuration of the acyl chains, irrespective of hydration state. Subtle changes in the dynamics of the lipids due to mobilization and incorporation of cholesterol and long-chain lipid species into the fluid lipid fraction is suggested to occur upon hydration, which can explain the changes of the impedance response. The results presented here provide information that is useful in explaining the effect of hydration on skin permeability.

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Section: The Effect Of Hydration On the Molecular Mobility Of Sc Components As Observed By Pt Ssnmrsupporting

confidence: 89%

Skin Membrane Electrical Impedance Properties under the Influence of a Varying Water Gradient

Björklund

Ruzgas

Nowacka

et al. 2013

Biophysical Journal

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“…Increasing water content increased the orientational disorder of the motionally restricted protons, which were ascribed to proteins, predominantly keratin, located within the corneocytes. Similar observations were reported by Packer and Sellwood 18 for powdered SC from guinea pig footpads and by Laule et al 25 for normal and psoriatic human SC, with psoriatic SC exhibiting more mobile lipid than normal SC. Silva et al 21 used wideline spectroscopy and 2D relaxation-chemical shift correlation spectra, along with T 2 and spectral measurements, to study water uptake by the SC.…”

Section: Introductionsupporting

confidence: 88%

“…Several published studies have examined molecular motion in SC from animals or humans using NMR techniques. Mainly these describe 1 H measurements (for example [17][18][19][20][21][22][23][24][25] ), although a few have examined deuterium ( 2 H) 24,26 or carbon ( 13 C) 27,28 . To our knowledge no prior NMR studies of SC from humans or animals have investigated the presence of an absorbed exogenous lipophilic compound.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Water and a Model Lipophilic Compound in Human Stratum Corneum by NMR Spectroscopy and Equilibrium Sorption

Kodiweera

Romonchuk

Yang

et al. 2016

Journal of Pharmaceutical Sciences

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The stratum corneum (SC) is the outermost skin layer in humans and other mammals and the primary barrier to water loss and environmental exposure to chemicals and microorganisms. It consists of flattened, keratin-filled corneocytes surrounded by well-organized lipid layers. Human SC at varying degrees of hydration with and without addition of a model lipophilic compound, 2-(trifluoromethyl) benzonitrile (TFMB), was studied using proton (H) and fluorine (F) nuclear magnetic resonance techniques. Proton spectral analyses revealed that water mainly occupies the corneocytes in agreement with prior studies. Observations from F spectral and spin-lattice relaxation time (T) analyses showed that TFMB is primarily present in the lipids with small amounts in water, which is located within the corneocytes. This is consistent with TFMB sorption, which was measured in SC with and without lipid extraction. The presence of TFMB within the corneocytes supports the hypothesis that transcellular diffusion of a lipophilic compound like TFMB may contribute to SC permeation.

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“…[18][19][20][21] More importantly, the barrier properties depend on the organization and molecular dynamics of the non-aqueous SC lipid and protein components. [19][20][21][22][23][24] We hypothesize that naturally occurring osmolytes may inuence the molecular dynamics of the SC constituents in a similar manner to water. 21,22 To investigate this, we employ natural-abundance 13 C solid-state NMR methods that provide molecular resolution on the chemical shi scale in combination with selective screening of mobile or rigid segments of the SC lipid and protein components.…”

Section: A Introductionmentioning

confidence: 99%

Stratum corneum molecular mobility in the presence of natural moisturizers

et al. 2014

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The outermost layer of the skin, the stratum corneum (SC), is a lipid-protein membrane that experiences considerable osmotic stress from a dry and cold climate. The natural moisturizing factor (NMF) comprises small and polar substances, which like osmolytes can protect living systems from osmotic stress. NMF is commonly claimed to increase the water content in the SC and thereby protect the skin from dryness. In this work we challenge this proposed mechanism, and explore the influence of NMF on the lipid and protein components in the SC. We employ natural-abundance (13)C solid-state NMR methods to investigate how the SC molecular components are influenced by urea, glycerol, pyrrolidone carboxylic acid (PCA), and urocanic acid (UCA), all of which are naturally present in the SC as NMF compounds. Experiments are performed with intact SC, isolated corneocytes and model lipids. The combination of NMR experiments provides molecularly resolved qualitative information on the dynamics of different SC lipid and protein components. We obtain completely novel molecular information on the interaction of these NMF compounds with the SC lipids and proteins. We show that urea and glycerol, which are also common ingredients in skin care products, increase the molecular mobility of both SC lipids and proteins at moderate relative humidity where the SC components are considerably more rigid in the absence of these compounds. This effect cannot be attributed to increased SC water content. PCA has no detectable effect on SC molecular mobility under the conditions investigated. It is finally shown that the more apolar compound, UCA, specifically influences the mobility of the SC lipid regions. The present results show that the NMF components act to retain the fluidity of the SC molecular components under dehydrating conditions in such a way that the SC properties remain largely unchanged as compared to more hydrated SC. These findings provide a new molecular insight into how small polar molecules in NMF and skin care products act to protect the human skin from drying.

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A proton NMR study on the hydration of normal versus psoriatic stratum corneum: linking distinguishable reservoirs to anatomical structures

Cited by 6 publications

References 42 publications

Skin Membrane Electrical Impedance Properties under the Influence of a Varying Water Gradient

Skin Membrane Electrical Impedance Properties under the Influence of a Varying Water Gradient

Characterization of Water and a Model Lipophilic Compound in Human Stratum Corneum by NMR Spectroscopy and Equilibrium Sorption

Stratum corneum molecular mobility in the presence of natural moisturizers

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