皮肤屏障功能与润肤保湿霜

1　皮肤屏障功能 (skinbarrierfunction)　　皮肤是人体最大的器官 ,它被盖于整个人体表面 ,总面积为 1 5～ 2m2 ,占人体总重量的 5 %。皮肤厚度为 0 5～ 4mm ,最外层为表皮 (epidermis) ,它由 5层角质形成细胞(keratinocytes)组成 ,最外层由 2 0层已死亡扁平无核的角质细胞所构成 ,内含角蛋白是皮肤的主要屏障和保护层。皮肤有许多功能 ,而首当其冲的是屏障功能 ,它既能防止外界化学、物理、机械、生物诸多因素的侵入 ;又能防止水份、营养物质经表皮而丢失。皮肤角质层含水量为 2 0 %～35 % ,如果低于 1 0 %皮肤就会干燥、粗糙、脱屑。…     

皮肤屏障功能与其神经鞘酯类关系的探讨

利用新生大鼠皮肤的培养，研究皮肤屏障功能与其神经鞘酯类的关系．结果发现皮肤屏障功能在培养后的第１天略有降低，以后恢复正常．第１０天起明显下降；皮肤的神经鞘酯类化合物随着培养时间的延长，乙酰神经酰胺，乙酰葡萄糖神经酰胺趋向降低，糖鞘酯呈显著下降，神经既胺趋向增高。结果提示皮肤屏障功能与神经鞘酯类的代谢有一定关系。     

皮肤屏障

皮肤屏障由水脂膜和皮肤“砖墙”结构构成。皮肤屏障结构和功能障碍与多种皮肤疾病的病因、病理过程相关。目前有多种无创检测方法可以评价皮肤的屏障功能。     

皮肤屏障研究方法的新进展

皮肤屏障为化学物经皮吸收的限速层,对维持机体内环境的稳定及抵御外环境的有害因素,有着重要的生理功能。深入研究皮肤屏障生理功能的首要任务就是建立科学有效的研究方法。本文从皮肤屏障的功能和结构两方面,对近年来应用于该领域研究方法的新进展作一概述。     

皮肤屏障与化妆品

本文根据国际美容皮肤科学会（ＩｎｔｅｒｎａｔｉｏｎａｌＳｏｃｉｅｔｙｏｆＣｏｓｍｅｔｉｃＤｅｒｍａｔｏｌｏｇｙ）秘书长Ｐｉｅｒ－ｆｒａｎｃｅｓｏＭｏｒｇａｎｔｉ，１９９６年７月１９日在南京所作学术报告的幻灯片内容整理     

皮肤屏障功能

1 皮肤屏障与皮肤病 皮肤屏障的结构基础主要是角质层以及表皮脂质。天然保湿因子等。表皮脂质包括神经酰胺、游离胆固醇和游离脂肪酸等，这些脂质在基底层细胞向角质层分化过程中，含量逐渐增高，到达角质层时被排出至细胞间隙，形成防止水分丢失的屏障。天然保湿因子是由表皮中的中间丝相关蛋白（filaggrin）分解形成，包含氨基酸、吡咯烷酮羧酸、尿刊酸、乳酸、尿素等多种低分子量物质，在角质层内与水结合而维持皮肤屏障功能。     

皮肤屏障与相关皮肤病

皮肤具有屏障、吸收、分泌、排泄、代谢、免疫、体温调节及感觉功能,其中,皮肤屏障(skin barrier)功能是基础,即对外抵抗抗原物质、微生物、日光等的侵袭,对内防止体内营养物质、水分的丢失,使皮肤维持正常的生理功能,预防某些皮肤病的发生[1].如果皮肤屏障受损,经表皮水分流失(TEWL)增加,皮肤将出现干燥、脱屑.同时,对外界抗原及微生物的抵御作用减弱,可诱发和加重某些皮肤病发生.     

GentleYAG 1064nm激光治疗对小鼠皮肤屏障功能及弹性的影响

目的研究GentleYAG1064nm激光嫩肤治疗对皮肤屏障功能的影响。方法GentleYAG1064nm激光照射小鼠背部皮肤,每周1次,在激光照射前、首次照射后1周、连续3次照射后1周和连续4次照射后4周时检测皮肤经表皮失水(tramsepidermalwaterloss,TEWL)、含水量和皮肤弹性的变化。结果首次激光照射小鼠皮肤后1周时TEWL,皮肤含水量和皮肤弹性基本上较正常对照组无显著性改变(P>0.05);连续3次激光照射小鼠皮肤后1周时TEWL值和皮肤含水量仍较正常对照组无显著性改变(P>0.05),但是皮肤弹性较正常对照组有显著性改善(P<0.05);连续4次激光照射小鼠皮肤后4周时TEWL值和皮肤含水量仍较正常对照组无显著性改变(P>0.05),皮肤弹性较正常对照组有显著性改善(P<0.05),其值高于连续3次激光照射后1周时,但两者间差异无显著性(P>0.05);用动态冷却系统(dynamiccoolingdevice,DCD)组和不用DCD组的TEWL值、皮肤含水量和皮肤弹性值在各个时间点上均无显著性差异(P>0.05)。结论①单次GentleYAG1064nm激光照射小鼠皮肤对皮肤屏障功能无明显的损伤。②多次GentleYAG1064nm激光照射可以改善皮肤弹性,说明多次GentleYAG1064nm激光照射有显著的嫩肤效果。③使用DCD对激光嫩肤效果无明显的促进作用。     

激素依赖性皮炎与皮肤屏障功能及修复

不当外用糖皮质激素可导致激素依赖性皮炎,短期外用可明显降低皮肤屏障功能的恢复速度,长期使用则会引起皮肤屏障结构的改变。激素依赖性皮炎具体发病机制较为复杂,皮肤屏障功能破坏可加重皮肤炎症反应。激素依赖性皮炎的治疗及使用糖皮质激素进行治疗的过程中应适当使用皮肤屏障保护产品;强脉冲光能明显改善激素依赖性患者皮肤的油脂、p H和弹性而不增加经皮水分丢失,因此对激素依赖性皮炎有较好疗效。     

角质形成细胞与皮肤免疫屏障

角质形成细胞(keratinocytes,KC)是皮肤免疫屏障中的重要一员.角质形成细胞可表达模式识别受体(pattern recognition receptor,PRR)识别病原体,启动固有免疫反应;角质形成细胞可作为抗原提呈细胞,参与抗原呈递,并分泌多种免疫活性分子参与皮肤免疫防御机制;还可表达抗菌肽直接杀灭或间接活化细胞因子防御病原体.烟酰胺腺嘌呤二核苷酸磷酸(nicotinamideadenine dinucleotide phosphate,NADPH)氧化酶参与上皮防御的机制则是新的研究热点,其在角质形成细胞的表达及影响因素尚待进一步研究.     

The relationship between skin function,barrier properties,and body‐dependent factors

Background

Skin is a multilayer interface between the body and the environment, responsible for many important functions, such as temperature regulation, water transport, sensation, and protection from external triggers.

Objectives

This paper provides an overview of principal factors that influence human skin and describes the diversity of skin characteristics, its causes and possible consequences. It also discusses limitations in the barrier function of the skin, describing mechanisms of absorption.

Methods

There are a number of in vivo investigations focusing on the diversity of human skin characteristics with reference to barrier properties and body‐dependent factors.

Results

Skin properties vary among individuals of different age, gender, ethnicity, and skin types. In addition, skin characteristics differ depending on the body site and can be influenced by the body‐mass index and lifestyle. Although one of the main functions of the skin is to act as a barrier, absorption of some substances remains possible.

Conclusions

Various factors can alter human skin properties, which can be reflected in skin function and the quality of everyday life. Skin properties and function are strongly interlinked.

     

皮肤屏障与银屑病研究进展

皮肤作为人体的第一道防线,对抵御外界有害因素的损伤以及维持人体内环境的稳态有着至关重要的作用。皮肤屏障的结构和功能与一些皮肤病的发生发展有着重要的联系。研究发现皮肤屏障功能受损可能是银屑病发生的重要诱因,然而皮肤屏障缺陷与银屑病发生的确切机制仍不清楚。该文主要对近年来皮肤屏障与银屑病的研究进展作一综述。     

表皮通透屏障功能对皮肤的调节作用及意义

表皮通透屏障功能除调节水分经表皮进出机体外,还对皮肤的其他生物功能如炎症、表皮增生、pH及离子的分布等也具有重要地调节作用。而且,维持表皮通透屏障功能在最佳水平有利于预防某些皮肤病的发生;改善皮肤屏障功能有助于某些皮肤病的治疗。     

The skin: an indispensable barrier

Abstract: The skin forms an effective barrier between the organism and the environment preventing invasion of pathogens and fending off chemical and physical assaults, as well as the unregulated loss of water and solutes. In this review we provide an overview of several components of the physical barrier, explaining how barrier function is regulated and altered in dermatoses. The physical barrier is mainly localized in the stratum corneum (SC) and consists of protein‐enriched cells (corneocytes with cornified envelope and cytoskeletal elements, as well as corneodesmosomes) and lipid‐enriched intercellular domains. The nucleated epidermis also contributes to the barrier through tight, gap and adherens junctions, as well as through desmosomes and cytoskeletal elements. During epidermal differentiation lipids are synthesized in the keratinocytes and extruded into the extracellular domains, where they form extracellular lipid‐enriched layers. The cornified cell envelope, a tough protein/lipid polymer structure, resides below the cytoplasmic membrane on the exterior of the corneocytes. Ceramides A and B are covalently bound to cornified envelope proteins and form the backbone for the subsequent addition of free ceramides, free fatty acids and cholesterol in the SC. Filaggrin is cross‐linked to the cornified envelope and aggregates keratin filaments into macrofibrils. Formation and maintenance of barrier function is influenced by cytokines, 3′,5′‐cyclic adenosine monophosphate and calcium. Changes in epidermal differentiation and lipid composition lead to a disturbed skin barrier, which allows the entry of environmental allergens, immunological reaction and inflammation in atopic dermatitis. A disturbed skin barrier is important for the pathogenesis of contact dermatitis, ichthyosis, psoriasis and atopic dermatitis.     

The face and neck: regional variation in skin barrier function and reactivity

Background/aims: Although there are many reports of regional variations in skin response to various stimuli, only a few studies have been performed on the face. The forearm is the most often used test site while the face is a frequent and specific target of many topical agents (drugs and cosmetics) and cosmetic procedures. The aim of this study was to compare regional variations of cutaneous sensation and skin barrier function in the cheek, neck and forearm before and after application of different stimuli (physical and/or chemical). Methods: Physiological changes of the skin were measured by non-invasive methods: TEWL (transepidermal water loss) and skin capacitance. Furthermore, clinical scoring and subjective sensations were reported. The anatomical sites evaluated were cheek, neck and volar forearm. Results: Great differences in clinical reactions, subjective sensations and skin barrier function in response to various stimuli have been observed between tested areas (cheek, neck and forearm). We observed a greater “sensitivity”, i.e., more severe clinical reactions and subjective sensations of the cheek and neck areas, in relation to chemical stimuli as compared to the forearm. After a mechanical stimulus, the forearm was the most sensitive site, but just for subjective sensations. Concerning skin barrier function, the cheeks exhibited the highest values of TEWL and the forearms the lowest. Conclusion: In view of the high “sensitivity” of the cheek as compared to the forearm, it will be more cautious to assess the safety of facial cosmetics on the sites of intended use.     

A topical lipophilic niacin derivative increases NAD, epidermal differentiation and barrier function in photodamaged skin

The effects of myristyl nicotinate (MN), a nicotinic acid derivative designed to deliver nicotinic acid to skin without vasodilatation, on subjects with photodamaged skin have been studied. MN increased skin cell nicotinamide adenine dinucleotide (NAD) by 25% (P = 0.001) demonstrating effective delivery of nicotinic acid to skin. Relative to placebo, MN treatment of photodamaged facial skin increased stratum corneum thickness by approximately 70% (P = 0.0001) and increased epidermal thickness by approximately 20% (P = 0.001). In two separate studies, MN treatment increased rates of epidermal renewal by 6% (P = 0.003) to 11% (P = 0.001) and increased the minimal erythemal dose by 8.9 (P = 0.07) and 10% (P = 0.05) relative to placebo. MN treatment resulted in reductions in the rates of transepidermal water loss (TEWL) of approximately 20% relative to placebo on cheeks (P = 0.012) and arms (P = 0.017) of study subjects. Results of a tape stripping challenge before and after MN treatment demonstrated a significant correlation (P = 0.03) between increased skin NAD content and resistance to changes in TEWL for MN treated but not placebo subjects. Rates of TEWL changed more rapidly and to a greater extent in atopic subjects compared with normal subjects. The results indicate that MN enhances epidermal differentiation and barrier function in skin, suggesting that this method of nicotinic acid delivery may prove useful in limiting progression of actinic skin damage and possibly in treating other conditions involving skin barrier impairment.     

Repair of acetone- and sodium lauryl sulphate-damaged human skin barrier function using topically applied emulsions containing barrier lipids

BACKGROUND: It is generally acknowledged that well-formulated moisturizing skin care products can restore disturbed barrier function that can be assessed by transepidermal water loss (TEWL) measurements. When ceramides and/or other barrier lipids are incorporated, it is, however, not always clearly demonstrated which ingredients of the formulation exert the beneficial effects. OBJECTIVES: In this study the effects of topically applied ceramide-containing mixtures on the barrier repair of sodium lauryl sulphate (SLS)- and acetone-induced skin damage have been studied in human volunteers. TEWL and stratum corneum hydration measurements were carried out. The emulsions applied contained either a mixture of two types of ceramides, CerIII and CerIIIB (emulsion 1) or a complete mixture of ceramides III, IIIB and VI together with phytosphingosine, cholesterol and the free fatty acid linoleic acid (emulsion 2). RESULTS: After SLS damage, it was observed that barrier recovery was significantly accelerated by topical application (14 days, 2 x/d) of emulsion 2 compared with the results obtained with emulsion 1. Corneometrical results were not relevant due to the occurrence of scaly fissured skin, failing to provide a good skin/probe contact. Although no effect on TEWL could be observed, the improvement of skin hydration after acetone treatment and a single application of the emulsions, was significantly more positive for emulsion 2 than for emulsion 1. CONCLUSIONS: The investigative methods used in this study show that ceramides combined with other skin lipids can improve barrier repair after damage.