Reduced barrier efficiency in axillary stratum corneum

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Research on understanding of the chemistry, function and (patho)-physiology of stratum corneum (SC) lipids and especially ceramides has evolved over the last two decades. This has been made successful through the application of separation techniques that have become increasingly more sophisticated, and it has become increasingly evident that our understanding of these molecules remains in its infancy. Thirteen classes of ceramides with over 300 and possibly up to 1000 distinct ceramide species have been identified suggesting an exquisitely subtle relationship between the types of ceramides and physical and chemical behaviour. Nevertheless, research has demonstrated the importance of the correct SC lipid lamellar architecture with conformationally-ordered lipid bilayers, the presence of long-chain ceramides, as either free or covalently bound lipids, greater quantities of phytosphingosine-containing ceramides and a high SC lipid/protein ratio is essential for optimal barrier function. These features are known to change in a variety of physiological and pathophysiological conditions. Clearly, there is more to be learned but as we further decipher the complexity of SC lipids and understand their individual roles in the SC, we will learn how to better treat the disorders of cornification.R esum e Des recherches sur la compr ehension de la chimie, de la fonction et de la (patho)physiologie des lipides du stratum corneum (SC) et en particulier des c eramides ont evolu e au cours des deux derni eres d ecennies. Cela a et e couronn e de succ es grâce a l'application de techniques de s eparation qui sont devenues de plus en plus sophistiqu ees et il est devenu de plus en plus evident que notre compr ehension de ces mol ecules reste a ses d ebuts. Treize classes de c eramides avec plus de 300 et eventuellement jusqu' a 1000 esp eces distinctes de c eramide ont et e identifi ees, ce qui sugg ere une relation tr es subtile entre les types de c eramides et le comportement physicochimique. N eanmoins, la recherche a d emontr e l'importance de l'exactitude de l'architecture lamellaire lipidique du SC avec la conformation en bicouches lipidiques, de la pr esence de c eramides a longue chaîne, qu'ils soient libres ou li es de fac ßon covalante, de la plus grandes quantit es de c eramides contenant de la phytosphingosine et un taux elev e de lipides / prot eines du SC, est essentiel pour une fonction de barri ere optimale. Ces caract eristiques sont connues pour varier suivant les conditions physiologiques et pathophysiologiques. De toute evidence, il y a plus a apprendre, mais a mesure que nous d echiffrions davantage la complexit e des lipides du SC et que nous comprenons leurs rôles individuels dans le SC, nous apprendrons a mieux traiter les troubles de la k eratinisation.

Section: Variations In Sc Ceramide Levelsmentioning

confidence: 97%

The chemistry, function and (patho)physiology of stratum corneum barrier ceramides

Moore¹,

Rawlings²

2017

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“…In this respect, further insights into differences in stratum corneum composition have also become evident on other body sites, especially the more humid axillary region of the body. Changes in the ceramide to cholesterol ratio has been described in the axillary region and using FTIR a more ordered lipid lamellae behaviour was found, suggesting that the elevated cholesterol levels might phase separate causing a reduced barrier function [86].…”

Section: Other Physiological Changes In Stratum Corneum Compositionmentioning

confidence: 99%

Trends in stratum corneum research and the management of dry skin conditions

Rawlings¹

2003

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172

140

The structure, composition, formation and function of the stratum corneum have been the subject of intense research over the last few decades. As has become apparent, stratum corneum barrier function is not only dependent on one single component but also on its total architecture. Recent developments in understanding lipid composition have led to a new ceramide nomenclature system, a new proposal for a molecular model of the interactions between ceramides, cholesterol and fatty acids, and the demonstration of the presence of crystalline orthorhombic and gel hexagonal lipid phases in the stratum corneum. Linoleate-containing ceramide one, now known as CER EOS, have been shown to be essential for the formation of the 13 nm long periodicity phase (LPP) observed by electron microscopy and X-ray diffraction studies, whereas long-chain fatty acids are important for the formation of the crystalline lipid phases essential for barrier function. The role of the corneocyte envelope, its constituent proteins and its transglutaminase-mediated maturation processes have been shown to be essential for good skin condition. Several proteases may have a role in corneodesmolysis, particularly serine and cathepsin-like enzymes. Novel filaggrin polymorphisms have been identified that may be involved in the expression of a dry skin phenotype. Disturbances in lipid packing states, reduction in ceramide levels (particularly the phytosphingosine-containing ceramides), reductions in the levels of long-chain fatty acids and loss of the LPP largely account for the perturbations in lipid structure that occur in dry skin. The reduced corneodesmolysis that occurs in this xerotic skin disorder is now well accepted and is caused by reductions in the levels and activities of stratum corneum proteases together with elevated levels of corneodesmosomal glycoproteins in the superficial layers of the stratum corneum. Additionally, increased levels of fragile corneocytes are associated with reduced transglutaminase activity and corneocyte envelope cross-linking events. However, in comparison with the advances in our understanding of the textural changes that occur in dry skin, the somatosensory changes are poorly understood and the itching associated with dry skin is still an under-researched area. The unique biosensor role of the stratum corneum essential for a competent natural moisturizing barrier may also have a role to play in the action of anti-ageing technologies by controlling the expression and secretion of epidermal cytokines and growth factors. Technologies to treat the surface textural skin problems, enhance the differentiation process, particularly lipid biosynthesis, and to control the somatosensory problems in dry skin have received much attention in the last decade. This paper will review the state of the art of stratum corneum biology and the trends in the management of dry skin.

“…As a result, consumers apply anti‐perspirant or deodorant products daily to minimize sweat and malodor. Several papers have been published characterizing the axilla in terms of its thickness, susceptibility to irritation, barrier properties and lipid content [5, 6]. However, few reports have described the skin compositional differences between the axilla and other skin sites, and fewer reports have demonstrated the utility of using the confocal Raman spectrometer to study axilla skin.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the composition of underarm and forearm skin using confocal raman spectrscopy

Kilpatrick‐Liverman

2011

Many studies have reported differences in skin composition as a function of body site and age. However, rarely has axilla (underarm) skin been included in these studies. This report highlights the results of a clinical study where confocal Raman spectroscopy was used to assess the differences between underarm and volar forearm skin. In the reported study, the concentration of natural moisturizing factor (NMF), urea, lactic acid, cholesterol, trans urocanic acid (t-UCA) and ceramide 3 (N-octadecanoyl-phytosphingosine) was evaluated as a function of depth, body site (underarm vs. forearm) and age. Two age groups of women were included: (i) between 20 and 30 years and (ii) older than 55 years (post-menopause). The levels of cholesterol, ceramide 3 and lactic acid were highest in the underarm regardless of the age group whereas the forearm contained higher amounts of NMF. Ceramide 3, urea and lactic acid were significantly lower for women 55 years or older in the underarm. No age-related differences were detected within the forearm site..