Stratum corneum swelling. Biophysical and computer assisted quantitative assessments

Norlén, Lars; Emilson, Axel; Forslind, B

doi:10.1007/s004030050231

Cited by 79 publications

(58 citation statements)

References 5 publications

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“…A volume of 250 l formulation, corresponding to a TACA dose of 100 g/cm 2 , was uniformly applied to the delineated area with a Hamilton syringe (Supelco, Buchs, Switzerland). The vehicle was allowed to evaporate.…”

Section: Application Of the Formulationmentioning

confidence: 99%

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Topical Bioavailability of Triamcinolone Acetonide: Effect of Occlusion

Pellanda¹,

Strub²,

Figueiredo³

et al. 2006

Skin Pharmacol Physiol

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Background/Aims: Occlusion by covering the skin with an impermeable wrap enhances skin hydration, affects drug absorption and can induce the formation of a drug reservoir within the stratum corneum. This is desired in local therapy with topical corticosteroids. The aim of the study was to investigate the effect of occlusion before (experiment 1) and after (experiment 2) application on the penetration of triamcinolone acetonide (TACA) into the stratum corneum. Methods: The experiments were conducted on the forearms of 10 healthy volunteers. In experiment 1, 100 µg/cm² TACA in acetone were applied on 3 sites per arm, one arm having been pre-occluded for 16 h. In experiment 2, the same dose was applied on 2 sites per arm, and one arm was occluded after application until skin sampling. Stratum corneum samples were removed by tape stripping at 0.5, 4 and 24 h (experiment 1) and 4 and 24 h (experiment 2) after application. Corneocytes and TACA were quantified by ultraviolet-visible spectroscopy and HPLC, respectively. The total TACA amount penetrated into the stratum corneum was evaluated by multifactor ANOVA. Results: TACA penetration into the stratum corneum with and without pre-occlusion (experiment 1) showed no significant difference and decreased with time. Occlusion after application (experiment 2) produced a marked TACA accumulation within the stratum corneum, which persisted for 24 h. Conclusion: Pre-occlusion showed no effect on the topical bioavailability of TACA in the stratum corneum. In contrast, post-occlusion enhanced the TACA penetration by a factor of 2, favouring the development of a drug reservoir.

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Section: Application Of the Formulationmentioning

confidence: 99%

“…The enhanced skin hydration can induce morphological changes of the stratum corneum such as swelling of the corneocytes [2] , water uptake into intercellular lipid domains [3] and deepening of skin furrows [4] .…”

Section: Introductionmentioning

confidence: 99%

Topical Bioavailability of Triamcinolone Acetonide: Effect of Occlusion

Pellanda¹,

Strub²,

Figueiredo³

et al. 2006

Skin Pharmacol Physiol

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“…Data published on the natural water content of normal SC range from 10 to 20% in ex vivo investigations [5,6] to about 35% in in vivo Raman measurements [4]. Changes in the whole SC upon water uptake have been investigated by Norlén et al [7] using confocal laser scanning microscopy: after treatment with distilled water SC swelling was 8% in area and 26% in thickness. However, due to the typical thickness of corneocytes (around 200-500 nm), investigation at the level of single corneocytes by optical microscopy is rather difficult, especially if changes in thickness need to be measured.…”

Section: Introductionmentioning

confidence: 99%

Dead but Highly Dynamic – The Stratum corneum Is Divided into Three Hydration Zones

Richter

Peuckert

Sattler

et al. 2004

Skin Pharmacol Physiol

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Topically applied water exerts mechanical stress on individual corneocytes as well as on the whole stratum corneum (SC), resulting in an alteration of barrier function. In this study we used complete skin biopsies and showed that the SC reacts to water stress as a highly optimized and well-regulated structure against osmotic changes. Following a relatively new cryo-processing protocol for cryo-SEM, it is possible to reliably maintain and investigate the hydrated state of the SC and individual corneocytes after treatment with solutions of different ionic strength. Treatment with distilled water results in swelling of SC cells together with formation of massive water inclusions between adjacent cell layers. Treatment with 5–20% NaCl reveals three different hydration zones within the SC: Corneocytes near the live-dead transition zone can swell to nearly double their thickness. The second zone is the most compact, as the corneocytes here show the smallest thickness variation with all treatments. Within the outermost zone, again a massive swelling and loosening of intracellular filament packing can be observed. We therefore conclude that the SC itself is subdivided into three functional zones with individual water penetration and binding potentials. Since the second zone remains nearly unaffected by water stress, we propose that this zone hosts the functional SC barrier.

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“…The outermost stratum corneum of mammalian skin is composed of corneocytes, whose interior is dominated by the presence of arrays of helical keratin macrofibres [9]. On exposure to water, corneocytes can swell to many times their initial volume without significant degradation of the structural integrity of the stratum corneum [10], owing to the uptake of bulk water, which occupies the fibre interstices [11]. On hydration, the corneocytes swell with little change in their total fibre content or keratin dimensions, though their helical pitch is likely to vary.…”

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confidence: 99%

From three-dimensional weavings to swollen corneocytes

Evans

Hyde

2011

J. R. Soc. Interface.

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A novel technique to generate three-dimensional Euclidean weavings, composed of closepacked, periodic arrays of one-dimensional fibres, is described. Some of these weavings are shown to dilate by simple shape changes of the constituent fibres (such as fibre straightening). The free volume within a chiral cubic example of a dilatant weaving, the ideal conformation of the G 129 weaving related to the S þ rod packing, expands more than fivefold on filament straightening. This remarkable three-dimensional weaving, therefore, allows an unprecedented variation of packing density without loss of structural rigidity and is an attractive design target for materials. We propose that the G 129 weaving (ideal S þ weaving) is formed by keratin fibres in the outermost layer of mammalian skin, probably templated by a folded membrane. Keywords: intermediate filaments; entangled weavings; dilatant materialsWe have developed a technique to generate a variety of crystalline close-packed arrays of one-dimensional filaments, via projection of line arrays in two-dimensional hyperbolic space into conventional three-dimensional space. The procedure relies on mapping of the hyperbolic patterns onto three-periodic minimal surfaces (TPMS), generalizing a technique used to enumerate systematically crystalline nets [1]. A rich catalogue of three-dimensional weavings can be constructed using this technique, with varying degrees of entanglement between filaments. Indeed, the entanglement can be tuned by adjusting the orientation of the line arrays in the hyperbolic plane, thereby varying the pitch of filament windings around channels of the TPMS. Generic examples are woven from curved and twisted filaments, whose detailed form depends on their trajectories on the TPMS [2]. Since these weavings contain close-packed fibres that can unwind at constant fibre volume without unjamming, they offer novel geometries for dilatant structures. An intriguing natural material that can sustain significant variations in fibre-packing densities is corneocytes, which make up the bulk of the outermost layer of mammalian skin, the stratum corneum. Corneocytes contain predominantly packed keratin fibrils, whose arrangement remains uncertain. We have found a dilatant chiral weaving with cubic symmetry that admits a sevenfold increase in the free volume on straightening the fibres cooperatively. The porosity variations exhibited by this weaving match closely the observed variations in human stratum corneum water contents. Further, the geometry of keratin intermediate filaments (IFs) deduced from X-ray crystallography matches well with data for fibres within this weaving in its canonical configuration, corresponding to unhydrated corneocytes.Since the specific curvilinear form of component filaments within a weaving can be varied without changing its entanglement, it is helpful to formulate a canonical geometry for each weaving. We have adapted algorithms developed to form canonical 'ideal' or 'tight' embeddings of knots [3,4] to arrive at these canonical embeddings...

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Stratum corneum swelling. Biophysical and computer assisted quantitative assessments

Cited by 79 publications

References 5 publications

Topical Bioavailability of Triamcinolone Acetonide: Effect of Occlusion

Topical Bioavailability of Triamcinolone Acetonide: Effect of Occlusion

Dead but Highly Dynamic – The Stratum corneum Is Divided into Three Hydration Zones

From three-dimensional weavings to swollen corneocytes

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