特应性皮炎与肠道微生物组的相关性

近期研究表明肠道的生态失调与免疫反应的改变和特应性皮炎(atopic dermatitis, AD)有关。通过总结AD和肠道菌群相关的实验和测序结果发现，肠道菌群通过免疫、代谢和神经内分泌途径对AD的发生发展有重要影响。本文就特应性皮炎与肠道微生物的相关性进行综述。     

The microbiome and atopic eczema: More than skin deep

Discoveries in the defective molecular composition of the epidermal barrier, such as the epidermal protein filaggrin, in those with atopic eczema (or atopic dermatitis [AD]) have proved crucial in understanding this disease, but its aetiology remains to be fully elucidated. The epidermal barrier is just one interface between the microbial world and our immune system. Recent advances in molecular technology have demonstrated for the first time the true scale of the normal human microbiome and changes seen in disease states. In this review article we discuss the role of the human microbiome in the aetiology and maintenance of AD. The role of Staphylococcus aureus within the skin microbiome is examined, in addition to the role of other bacteria and fungi, identified using novel culture‐independent methods. The significant contribution of the gut microbiome and its manipulation via probiotic use is also reviewed. We emphasise that the microbiome of separate systems, including the gut, has a significant role to play in the manifestation of this cutaneous disorder. To date, there has been a lack of studies investigating whether changes to the lung microbiome may play a role in AD. An early interaction between the microbiome and immune system via multiple routes (skin–gut–lung) could feasibly affect the risk of a subsequent development of atopic diseases. When making management decisions for AD patients, clinicians must be mindful of the role of the microbiome.     

The Gut Microbiome: Human Health and Inflammatory Skin Diseases

The human microbiome is a rich environment consisting of bacteria, fungi and other commensal microorganisms of the gut, mucosa and skin. The functional role of the gut microbiome includes facilitation in metabolism of macronutrients, maturation of the immune system, and production of pro- or anti-inflammatory signaling molecules and peptides. The identification of these resident organisms has brought about a new understanding of disease processes. Nevertheless, more questions remain regarding the interactions within the microbiome, its interactions with the host, and its contributions to the pathophysiology of disease. The purpose of this review is to examine the existing medical literature to highlight the role of the gut microbiome in human health, also paying attention to its role in several inflammatory skin diseases, namely atopic dermatitis, psoriasis, and rosacea.     

Experimental metagenomics and ribosomal profiling of the human skin microbiome

The skin is the largest organ in the human body, and it is populated by a large diversity of microbes, most of which are co‐evolved with the host and live in symbiotic harmony. There is increasing evidence that the skin microbiome plays a crucial role in the defense against pathogens, immune system training and homoeostasis, and microbiome perturbations have been associated with pathological skin conditions. Studying the skin resident microbial community is thus essential to better understand the microbiome‐host crosstalk and to associate its specific configurations with cutaneous diseases. Several community profiling approaches have proved successful in unravelling the composition of the skin microbiome and overcome the limitations of cultivation‐based assays, but these tools remain largely inaccessible to the clinical and medical dermatology communities. The study of the skin microbiome is also characterized by specific technical challenges, such as the low amount of microbial biomass and the extensive human DNA contamination. Here, we review the available community profiling approaches to study the skin microbiome, specifically focusing on the practical experimental and analytical tools necessary to generate and analyse skin microbiome data. We describe all the steps from the initial samples collection to the final data interpretation, with the goal of enabling clinicians and researchers who are not familiar with the microbiome field to perform skin profiling experiments.     

The skin microbiome: Associations between altered microbial communities and disease

A single square centimetre of the human skin can contain up to one billion microorganisms. These diverse communities of bacteria, fungi, mites and viruses can provide protection against disease, but can also exacerbate skin lesions, promote disease and delay wound healing. This review addresses the current knowledge surrounding the healthy skin microbiome and examines how different alterations to the skin microbial communities can contribute to disease. Current methodologies are considered, changes in microbial diversity and colonisation by specific microorganisms are discussed in the context of atopic dermatitis, psoriasis, acne vulgaris and chronic wounds. The recent impact of modern Westernised lifestyles on the human skin microbiome is also examined, as well as the potential benefits and pitfalls of novel therapeutic strategies. Further analysis of the human skin microbiome, and its interactions with the host immune system and other commensal microorganisms, will undoubtedly elucidate molecular mechanisms for disease and reveal gateways for novel therapeutic treatment strategies.     

Microbiome and pediatric atopic dermatitis

Atopic dermatitis is a chronic inflammatory skin condition with drastic impacts on pediatric health. The pathogenesis of this common disease is not well understood, and the complex role of the skin microbiome in the pathogenesis and progression of atopic dermatitis is being elucidated. Skin commensal organisms promote normal immune system functions and prevent the colonization of pathogens. Alterations in the skin microbiome may lead to increased Staphylococcus aureus colonization and atopic dermatitis progression. Despite the evidence for their important role, probiotics have not been deemed efficacious for the treatment of atopic dermatitis, although studies suggest that probiotics may be effective at preventing the development of atopic dermatitis when given to young infants. This review will cover the most recent published work on the microbiome and pediatric atopic dermatitis.     

Skin diseases associated with atopic dermatitis

Atopic dermatitis is a common chronic pruritic inflammatory skin disorder, characterized by an abnormal skin barrier, immune dysfunction, and an altered skin microbiome. Atopic dermatitis may be seen in conjunction with a variety of other skin disorders due to the complex pathogenesis of atopic dermatitis, involving genetic and environmental factors that are associated with immune dysfunction, barrier defects, and altered skin microbiomes. Skin disorders associated with atopic dermatitis include diseases sharing similar genetic origins like ichthyosis vulgaris, infectious diseases such as impetigo, and eczema herpeticum, in addition to the cutaneous autoimmune diseases, alopecia areata, and vitiligo. Atopic dermatitis is also often linked to such benign conditions as pityriasis alba and keratosis pilaris. This review discusses the cutaneous comorbidities of atopic dermatitis and their relationship via their occurrence in conjunction with atopic dermatitis.     

Skin microbiota: Friend or foe in pediatric skin health and skin disease

The human integument and gastrointestinal tract host unique microbial ecosystems. Within the last decade, research has focused on understanding the contributions of the microbiota to human health and disease. The majority of skin microbiome studies involve adults. This review focuses on key studies conducted within the pediatric population and provides a framework for future skin microbiome work in this ever‐expanding field. This article begins by exploring the skin microbiome at birth and reviews the impact of delivery mode on infant skin colonization. How skin microbial colonization evolves from infancy to adulthood and normal development impacts the abundance of skin commensals such as Streptococcus, Staphylococcus, and Cutibacterium is also highlighted. Finally, several skin microbiome research studies in common pediatric skin conditions are reviewed, including body odor, atopic dermatitis (AD), and acne. The bacteria involved in metabolizing sweat, the impact on body odor, and how this process evolves from childhood to adulthood is outlined. In AD, different bacteria genera that predominate in children and adults and the impact of current AD therapies on skin microbiota are explored. Finally, in acne, the understanding of how Cutibacterium acnes contributes to acne pathogenesis and how acne therapies impact the skin microbial communities is reviewed.     

马拉色菌相关婴儿皮肤病

马拉色菌是人皮肤表面的常驻真菌，能引起婴儿花斑癣，并与婴儿脂溢性皮炎、婴儿特应性皮炎、新生儿头部脓疱病、婴儿及新生儿痤疮的发病相关。这种相关性主要表现在皮损处能检出马拉色菌，且抗真菌治疗有效，在婴儿特应性皮炎的发病中，主要作为抗原。由于婴儿和新生儿的皮肤屏障功能、机体免疫功能等尚不成熟，在患该类疾病时临床表现不典型，较成人有差异，治疗以外用药物为主。     

The skin microbiome and the gut-skin axis

The microbiome plays a significant role in human health, homeostasis, immune system, and disease pathogenesis. Disrupted communication between the microbiome and host has been extensively studied in gastrointestinal diseases. To a lesser extent, there is emerging research on the skin microbiome and its connection with the gut, referred to as the gut-skin axis and its effects on dermatologic conditions. A basic overview will be provided of the gut and skin microbiome with a focus on the impact of this connection on cutaneous diseases, such as psoriasis, atopic dermatitis, rosacea, acne vulgaris, photoaging, and cutaneous wounds. In addition, we shall discuss nutrition-based approaches mediated through the gut-skin axis and topical treatments that could serve as potential adjunctive management by manipulation of the microbiome. In particular, there is a growing body of research on oral probiotics, prebiotics, and dietary modifications that may help improve symptoms for a variety of dermatologic conditions in select demographic groups.     

Rosacea and the gastrointestinal system

Rosacea is a common skin condition characterised by erythema, papules and pustules. Increasing evidence suggests that the gut–skin axis is implicated in the pathogenesis of rosacea. Sufficient evidence exists to support the notion that the gut microbiome plays a role in the inflammatory cutaneous response and there appear to be associations with small intestinal bacterial overgrowth and Helicobacter pylori infection. A dysbiotic microbiome and an innate immune system dysregulation contribute to the pathophysiology of rosacea, and further exploration of their roles is warranted. Greater understanding of this condition and the effect of the gut–skin axis could allow for more efficacious and timely treatment. This article reviews our current findings and understanding in the skin and gut relationship in rosacea.     

The skin microbiome and immune system: Potential target for chemoprevention?

There has been increasing interest in understanding the role of the human microbiome in skin diseases. Microbiome studies are being utilized in skin cancer research in numerous ways. Commensal bacteria are being studied as a potential tool to judge the biggest environmental risk of skin cancer, ultraviolet (UV) radiation. Owing to the recognized link of skin microbes in the process of inflammation, there have been theories linking commensal bacteria to skin cancer. Viral metagenomics has also provided insight into virus linked forms of skin cancers. Speculations can be drawn for skin microbiome that in a manner similar to gut microbiome, they can be involved in chemoprevention of skin cancer. Nonetheless, there are definitely huge gaps in our knowledge of the relationship of microbiome and skin cancers, especially in relation to chemoprevention. The utilization of microbiome in skin cancer research seems to be a promising field and may help yield novel skin cancer prevention and treatment options. This review focuses on recent utilization of the microbiome in skin cancer research, and it explores the potential of utilizing the microbiome in prevention, earlier diagnosis, and treatment of skin cancers.     

Topical antioxidants protect the skin from chemical-induced irritation in the repetitive washing test: a placebo-controlled, double-blind study

Background. There is increasing evidence that reactive oxygen species play an important role in the development of both irritant and allergic contact dermatitis. Objectives. To assess the potential of topical antioxidants to prevent the development of experimentally induced irritant contact dermatitis. Methods. We evaluated the effect of a cream containing a combination of antioxidants on sodium lauryl sulfate-induced irritant contact dermatitis in the repetitive washing test. As readout parameters for skin barrier function and cutaneous inflammation stratum corneum hydration, cutaneous blood flow and transepidermal water loss were assessed in 25 volunteers with bioengineering methods. Results. In comparison with the cream base and a frequently used barrier cream, the antioxidant cream had high radical scavenging activity and effectively protected the skin from chemical-induced irritation. Conclusions. The superiority of the cream with antioxidants to the cream base suggests that reactive oxygen species, at least in part, play a role in the development of irritant contact dermatitis.     

Skin microbiome sampling in the preterm neonate

Despite advances in our understanding of the human microbiome, there exist significant knowledge gaps in our understanding of the skin microbiome of the preterm neonate. Herein, we describe skin microbiome sampling of six preterm neonates at multiple timepoints, and compare the skin microbiome samples to environmental (crib/isolette swabs) and negative controls. Samples of the same type (skin, crib, control) were more similar than when compared by week or by patient.     

Dissecting the role of infections in atopic dermatitis

In patients with atopic dermatitis the skin is highly susceptible to infection by bacteria, fungi and viruses. Increasing knowledge about the complex immune network that regulates anti-microbial responses has helped to dissect further the role of infections in atopic dermatitis. Conserved patterns of microbes are recognized by the innate immune system, which mediates microbicidal activity, either directly or through inflammatory responses. New evidence suggests that components of the innate immune system, such as anti-microbial peptides, humoural lectins, nucleotide-binding oligomerization domain-containing (NOD) proteins, and Toll-like receptors not only protect from microbial invasion, but contribute to skin inflammation in atopic dermatitis. In addition, atopic patients tend to develop Th2-dominated immune responses that weaken anti-microbial immunity. This impairment of an appropriate anti-microbial defence compounded by amplified microbe-driven innate and adaptive immune responses leads to the vicious circle of skin inflammation. New microbial management in atopic dermatitis will foster a well-balanced microbial flora, which establishes natural defence mechanisms to maintain immuno-surveillance of the skin. In addition to anti-microbial therapies, other innate immune stimuli may suppress pro-inflammatory signals and help to break the vicious circle of cutaneous inflammation. To elucidate further these different interactions of the skin immune system and microbes in atopic dermatitis, clinical studies and further efforts in basic research are needed.     

Diversity of the human skin microbiome early in life

Within days after birth, rapid surface colonization of infant skin coincides with significant functional changes. Gradual maturation of skin function, structure, and composition continues throughout the first years of life. Recent reports have revealed topographical and temporal variations in the adult skin microbiome. Here we address the question of how the human skin microbiome develops early in life. We show that the composition of cutaneous microbial communities evolves over the first year of life, showing increasing diversity with age. Although early colonization is dominated by Staphylococci, their significant decline contributes to increased population evenness by the end of the first year. Similar to what has been shown in adults, the composition of infant skin microflora appears to be site specific. In contrast to adults, we find that Firmicutes predominate on infant skin. Timely and proper establishment of healthy skin microbiome during this early period might have a pivotal role in denying access to potentially infectious microbes and could affect microbiome composition and stability extending into adulthood. Bacterial communities contribute to the establishment of cutaneous homeostasis and modulate inflammatory responses. Early microbial colonization is therefore expected to critically affect the development of the skin immune function.     

Loss of cutaneous microbial diversity during first 3 weeks of life in very low birthweight infants

Neonatal sepsis (NS) is a frequent problem in neonatal intensive care, especially in preterm and very low birthweight (VLBW) infants. The objective of the study was to characterize the cutaneous bacterial microbiome in VLBW infants treated in the neonatal intensive care unit (NICU). Non‐invasive skin microbiome specimens were taken repeatedly from 12 VLBW infants during treatment in NICU starting on the first day of life. All infants received benzylpenicillin and netilmicin during the first 1‐5 postnatal days. Samples were also collected from incubators. High cutaneous microbial diversity was present at birth in 11 of 12 of the infants, but the diversity decreased substantially after the first weeks of life in all infants regardless of their infection status. After the loss of diversity, one Staphylococcus operational taxonomic unit dominated the skin microbiome. Recovery of microbial diversity was seen in six of 12 neonates. The microbiome of incubators showed typical environmental bacterial genera. Maternal antibiotic treatment, the aetiology of the preterm birth or being born by C‐section did not appear to affect the diversity of skin microbiota at birth, and no correlation was found between cutaneous microbiome and NS.     

几种婴儿常见皮肤病的皮肤微生态研究进展

近年来报道婴儿期皮肤病可能与局部皮肤微生态失调关系较密切，本文综述了婴儿期特应性皮炎、新生儿痤疮、脂溢性皮炎、新生儿红斑和皮肤微生态关系。     

A review of the use of beeswax in skincare

Background

Beeswax is a naturally occurring product secreted from worker bees that has varied uses in modern day. In skincare, its function ranges from its role as an occlusive, helping to create a semi-occlusive skin barrier that minimizes transepidermal water loss; as a humectant, locking in hydration; and an emollient to soften and soothe the skin. As a natural substance, its use has been shown to help alleviate symptoms associated with common cutaneous conditions like dermatitis, psoriasis, and overgrowth of normal skin flora.

Aims

In this narrative review, we aim to describe current uses of beeswax in skincare that has been published in the literature.

Materials and methods

A review of beeswax related publications was performed by searching the PubMed database studies.

Results

A total of five clinical studies were included with three studies on animals and two studies in humans.

Discussion

Several studies show the benefits of topical beeswax in supporting the skin barrier.

Conclusion

Beeswax can be a low-cost, natural ingredient for use in products. Further studies with topical beeswax are warranted.     

TLR2 and TLR4 expression in atopic dermatitis,contact dermatitis and psoriasis

The aim of the study was to investigate the expression of Toll‐like receptors (TLRs) 2 and 4 on keratinocytes in atopic dermatitis, contact dermatitis, and psoriasis by PCR and by immunohistochemistry including confocal microscopy. Confocal microscopy revealed a granular intra‐cellular expression pattern for TLR 2 and a homogenous intra‐cellular expression pattern for TLR 4 in normal and diseased skin. TLR 2 was constitutively expressed in the suprabasal layers in normal skin, but limited to the basal epidermis in diseased skin. TLR 4 expression was concentrated to the basal layers in normal skin, whereas it was pronounced in upper layers in diseased skin. The shift in the TLR expression may be related to the disturbed skin barrier and a need for enhanced immune surveillance because of invading microbes. Also, there must be a balance between sufficient immune response and overstimulation.