Atopic Dermatitis and the Nervous System

Emergence of New Concepts in Skin Physiopathology through the Use of in vitro Human Skin Explants Models

BACKGROUND

This review summarizes uses and new applications for dermatological research of in vitro culture models of human skin explants (HSEs). In the last decade, many innovations have appeared in the literature and an exponential number of studies have been recorded in various fields of application such as process culture engineering, stem cell extractions methodology, or cell-to-cell interaction studies under physiological and pathological conditions, wound-healing, and inflammation. Most studies also concerned pharmacology, cosmetology, and photobiology. However, these topics will not be considered in our review.

SUMMARY

A better understanding of the mechanisms driving intercellular relationships, at work in the maintenance of 3D tissue architectures has led to the improvement of cell culture techniques. Many papers have focused on the physiological ways that govern in vitro tissue maintenance of HSEs. The analysis of the necessary mechanical stress, intercellular and cell-matrix interactions, allows the maintenance and prolonged use of HSEs in culture for up to 15 days, regardless of the great variability of study protocols from one laboratory to another and in accordance with the objectives set. Because of their close similarities to fresh skin, HSEs are increasingly used to study skin barrier repair and wound healing physiology. Easy to use in co-culture, this model allows a better understanding of the connections and interactions between the peripheral nervous system, the skin and the immune system. The development of the concept of an integrated neuro-immuno-cutaneous system at work in skin physiology and pathology highlighted by this article represents one of the new technical challenges in the field of in vitro culture of HSE. This review of the literature also reveals the importance of using such models in pathology. As sources of stem cells, HSEs are the basis for the development of new tissue engineering models such as organoids or optical clearing tissues technology. This study identifies the main advances and cross-cutting issues in the use of HSE.

Air Pollution: Possible Interaction between the Immune and Nervous System?

Exposure to environmental pollutants is a serious and common public health concern associated with growing morbidity and mortality worldwide, as well as economic burden. In recent years, the toxic effects associated with air pollution have been intensively studied, with a particular focus on the lung and cardiovascular system, mainly associated with particulate matter exposure. However, epidemiological and mechanistic studies suggest that air pollution can also influence skin integrity and may have a significant adverse impact on the immune and nervous system. Air pollution exposure already starts in utero before birth, potentially causing delayed chronic diseases arising later in life. There are, indeed, time windows during the life of individuals who are more susceptible to air pollution exposure, which may result in more severe outcomes. In this review paper, we provide an overview of findings that have established the effects of air pollutants on the immune and nervous system, and speculate on the possible interaction between them, based on mechanistic data.

Suppressive effect of 1,4-anhydro-4-seleno-D-talitol (SeTal) on atopic dermatitis-like skin lesions in mice through regulation of inflammatory mediators

BACKGROUND

Atopic dermatitis (AD) is a multifactorial chronic inflammatory disease that affects ∼20 % of children and 3% of adults globally and is generally treated by the topical application of steroidal drugs that have undesirable side-effects. The development of alternative therapies is therefore an important objective. The present study investigated the effects of topical treatment with a novel water-soluble selenium-containing carbohydrate derivative (4-anhydro-4-seleno-D-tatitol, SeTal) on the symptoms and inflammatory parameters in an AD mouse model.

METHODS

Mice were sensitized by applying 2,4-dinitrochlorobenzene (DNCB) to their dorsal skin on days 1-3, then further challenged on their ears and dorsal skin on days 14, 17, 20, 23, 26, and 29. SeTal (1 and 2%) or hydrocortisone (1%) was applied topically to the backs of the mice from days 14-29, and skin severity scores and scratching behavior determined on day 30. The mice were euthanized, and their ears and dorsal skin removed to quantify inflammatory parameters, edema, myeloperoxidase (MPO) activity, and AD-associated cytokines (tumor necrosis factor alpha (TNF-α), interleukins (IL)-18, and IL-33).

RESULTS

DNCB treatment induced skin lesions and increased the scratching behavior, ear edema, MPO activity (ear and dorsal skin), and cytokine levels in dorsal skin. Topical application of SeTal improved inflammatory markers (cytokine levels and MPO activity), cutaneous severity scores, and scratching behavior.

CONCLUSION

The efficacy of SeTal was satisfactory in the analyzed parameters, showing similar or better results than hydrocortisone. SeTal appears to be therapeutically advantageous for the treatment and control of AD.

Sleep Disturbances and Atopic Dermatitis: Relationships, Methods for Assessment, and Therapies

Atopic dermatitis is one of the most common chronic inflammatory skin conditions and is associated with sleep disturbances in 47% to 80% of children and 33% to 90% of adults. Herein, we review the literature on sleep disturbances experienced by patients with atopic dermatitis, as well as the mechanisms that may underlie this. We present subjective and objective methods for measuring sleep quantity and quality and discuss strategies for management. Unfortunately, the literature on this topic remains sparse, with most studies evaluating sleep as a secondary outcome using subjective measures. The development of portable, at-home methods for more objective measures offers new opportunities to better evaluate sleep disturbances in atopic dermatitis research studies and in clinical practice.

Cutaneous sensitivity modulation by Aquaphilus dolomiae extract-G3 on in vitro models of neuro-inflammation

BACKGROUND

Inflammatory skin disorders, including atopic dermatitis (AD), associated pruritus and sensitive skin, have a complex multifactorial pathogenesis including neurogenic inflammation involving the release in blood and skin of neurotransmitters such as substance P (SP).

AIMS AND METHODS

In vitro models evaluated the effect of the original biological extract of Aquaphilus dolomiae extract-G3 (ADE-G3) on cutaneous neurogenic inflammation.

RESULTS

ADE-G3 significantly inhibited SP-stimulated release of IL-1β and TNF-α from normal human epidermal keratinocytes; significantly and dose-dependently inhibited SP-stimulated activation of human mast cells; significantly inhibited veratridine-stimulated release of SP from human sensory neurons; modulated expression of genes involved in lipid synthesis, innate immunity, corneocyte scaffolding and epidermal differentiation in a histamine-sensitized reconstructed human epidermis model; and, when applied topically to ex vivo human explants, inhibited IL-8 and histamine release.

CONCLUSIONS

Topically applied ADE-G3, once formulated, may improve neuro-inflammation in patients with inflammatory skin disorders.

Novel charged sodium and calcium channel inhibitor active against neurogenic inflammation

Voltage-dependent sodium and calcium channels in pain-initiating nociceptor neurons are attractive targets for new analgesics. We made a permanently charged cationic derivative of an N-type calcium channel-inhibitor. Unlike cationic derivatives of local anesthetic sodium channel blockers like QX-314, this cationic compound inhibited N-type calcium channels more effectively with extracellular than intracellular application. Surprisingly, the compound is also a highly effective sodium channel inhibitor when applied extracellularly, producing more potent inhibition than lidocaine or bupivacaine. The charged inhibitor produced potent and long-lasting analgesia in mouse models of incisional wound and inflammatory pain, inhibited release of the neuropeptide calcitonin gene-related peptide (CGRP) from dorsal root ganglion neurons, and reduced inflammation in a mouse model of allergic asthma, which has a strong neurogenic component. The results show that some cationic molecules applied extracellularly can powerfully inhibit both sodium channels and calcium channels, thereby blocking both nociceptor excitability and pro-inflammatory peptide release.

Current pharmaceutical developments in atopic dermatitis

Atopic dermatitis (AD) is an inflammatory, pruritic, chronic or chronically relapsing skin disease that typically begins in early childhood and is occurring frequently in families with other atopic diseases (bronchial asthma and/or allergic rhino-conjunctivitis). Thanks to immunological and neurobiological research, the era of new treatments is coming as well as it occurred with psoriasis 15 years ago. Many treatments targeting cytokines (IL-4, IL-13, IL-31, TSLP) or neurotransmitters (substance P, opioids) or their respective receptors as well as phosphodiesterase-4 or the Jak/Stat pathways are under development. Antagonists of cytokines and anti-jak have promising effects on pruritus while it is more difficult to discriminate the effects of other drugs from the placebo effect on itch, which is known to be high.

Host Peptidic Hormones Affecting Bacterial Biofilm Formation and Virulence

Bacterial biofilms constitute a critical problem in hospitals, especially in resuscitation units or for immunocompromised patients, since bacteria embedded in their own matrix are not only protected against antibiotics but also develop resistant variant strains. In the last decade, an original approach to prevent biofilm formation has consisted of studying the antibacterial potential of host communication molecules. Thus, some of these compounds have been identified for their ability to modify the biofilm formation of both Gram-negative and Gram-positive bacteria. In addition to their effect on biofilm production, a detailed study of the mechanism of action of these human hormones on bacterial physiology has allowed the identification of new bacterial pathways involved in biofilm formation. In this review, we focus on the impact of neuropeptidic hormones on bacteria, address some future therapeutic issues, and provide a new view of inter-kingdom communication.

Sleep disorders and atopic dermatitis: A 2-way street?

Sleep disturbance is very common in patients with atopic dermatitis (AD) and is a major factor leading to impaired quality of life. Sleep disturbance is often viewed as one of the symptoms of AD and one of the measures of disease severity. In this review we describe a variety of sleep disorders associated with AD and a wide range of effect that sleep disorders have on patients with AD. We also discuss our current understanding of the mechanism of sleep disturbance in patients with AD. The relationship between sleep disorders and AD might be bidirectional and could form a vicious cycle. Therefore we suggest viewing sleep disorders as a comorbidity of AD for which regular screening and bidirectional management strategies are indicated, with equal focus on maintaining disease control and implementing specific strategies to improve sleep.

Adjunctive Management of Itch in Atopic Dermatitis

Itch, or pruritus, is a hallmark feature of atopic dermatitis (AD). The impact of AD-related pruritus can range from mildly distressing or distracting to completely disabling. Traditionally, management of itch in AD patients has focused on restoring the altered skin barrier with topical emollients and/or reducing inflammation. A growing emphasis has been placed on directly targeting the neural transmission pathways that mediate itch signaling. Off-label use of neuromodulatory agents has helped reduce this aggravating symptom in atopic patients. This article reviews the current literature on the use of neuromodulatory agents and nonpharmacologic alternative therapies used to treat AD-related pruritus.

Topical treatments of Saussurea costus root and Thuja orientalis L. synergistically alleviate atopic dermatitis-like skin lesions by inhibiting protease-activated receptor-2 and NF-κB signaling in HaCaT cells and Nc/Nga mice

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Saussurea costus (Aucklandia lappa Decne, Aucklandiae Radix, SC) and Thuja orientalis L. (TOL) have been traditionally used as anti-inflammatory agents in Korea. However, they have not been studied for the efficacy of atopic dermatitis (AD) treatment, a chronic inflammatory skin disease. We investigated the efficacy of topical applications with 1,3-butyleneglycol extracts of SC and TOL to alleviate the symptoms of AD.

MATERIALS AND METHODS

HaCaT cells and the dorsal skin of Nc/Nga mice had a local exposure of house mite extracts and 2,4-dinitrochlorobenzene (DNCB), respectively. After lesions developed, we topically applied 1,3-butylen glycol (vehicle; control), SC (30%), TOL (30%), or SC (15%)+TOL (15%) to the skin lesions for 5 weeks. The normal-control was not exposed to DNCB. The skin thickness, mast cell infiltration, serum immunoglobulin E (IgE) and IgG1 and gene expressions of interleukin (IL)-4, IL-13, and IFN-γ in the dorsal skin and HaCaT cells were measured.

RESULTS

Chlorogenic acid (129.6±10.2μg/g) for SC and catechin and apigenin (93.4±13.2 and 16.9±1.3μg/g, respectively) for TOL were used as indicator compounds for the strength of the extracts. SC+TOL decreased the expression of protease-activated receptor-2 and ICAM-1 and the release of TNF-α and IL-6 in HaCaT cells activated by 3μg/mL house mite extracts in comparison to either of SC or TOL alone. In Nc/Nga mice challenged with DNCB, SC+TOL synergistically attenuated clinical symptoms of AD such as erythema, hemorrhage, edema, excoriation and dryness in the dorsal skin better than either SC or TOL alone. Histological analysis of the dorsal skin also showed that SC+TOL treatment significantly and additively decreased the inflammatory cellular infiltrate, including mast cells and eosinophils in comparison to either of SC or TOL. SC+TOL also decreased serum IgE and IgG1 levels and the expression of IFN-γ, IL-4, and IL-13 mRNA in dorsal skin in DNCB-treated Nc/Nga mice.

CONCLUSION

SC+TOL relieved the symptoms of AD by reducing pro-inflammatory activity and over-activated immune responses. These data suggest that SC+TOL may be an effective alternative intervention for the management of AD.

A research design for the quantification of the neuropeptides substance p and calcitonin gene-related Peptide in rat skin using Western blot analysis

OBJECTIVE

To describe and standardize a protocol that overcomes the technical limitations of Western blot (WB) analysis in the quantification of the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) following nociceptive stimuli in rat skin.

DESIGN

Male Wistar rats (Rattus norvegicus albinus) weighing 250 to 350 g were used in this study. Elements of WB analysis were adapted by using specific manipulation of samples, repeated cycles of freezing and thawing, more thorough maceration, and a more potent homogenizer; increasing lytic reagents; promoting greater inhibition of protease activity; and using polyvinylidene fluoride membranes as transfer means for skin-specific protein. Other changes were also made to adapt the WB analysis to a rat model.

SETTING

University research center.

MAIN OUTCOME MEASURE

Western blot analysis adapted to a rat model.

RESULTS

This research design has proven effective in collecting and preparing skin samples to quantify SP and CGRP using WB analysis in rat skin.

CONCLUSION

This study described a research design that uses WB analysis as a reproducible, technically accessible, and cost-effective method for the quantification of SP and CGRP in rat skin that overcomes technical biases.

Atopic dermatitis: allergic dermatitis or neuroimmune dermatitis?

Advances in knowledge of neurocellulars relations have provided new directions in the understanding and treatment of numerous conditions, including atopic dermatitis. It is known that emotional, physical, chemical or biological stimuli can generate more accentuated responses in atopic patients than in non-atopic individuals; however, the complex network of control covered by these influences, especially by neuropeptides and neurotrophins, and their genetic relations, still keep secrets to be revealed. Itching and airway hyperresponsiveness, the main aspects of atopy, are associated with disruption of the neurosensory network activity. Increased epidermal innervation and production of neurotrophins, neuropeptides, cytokines and proteases, in addition to their relations with the sensory receptors in an epidermis with poor lipid mantle, are the aspects currently covered for understanding atopic dermatitis.

Effect of Substance P in Staphylococcus aureus and Staphylococcus epidermidis Virulence: Implication for Skin Homeostasis

Staphylococcus aureus and Staphylococcus epidermidis are two major skin associated bacteria, and Substance P (SP) is a major skin neuropeptide. Since bacteria are known to sense and response to many human hormones, we investigated the effects of SP on Staphylococci virulence in reconstructed human epidermis model and HaCaT keratinocytes. We show that SP is stimulating the virulence of S. aureus and S. epidermidis in a reconstructed human epidermis model. qRT-PCR array analysis of 64 genes expressed by keratinocytes in the response to bacterial infection revealed a potential link between the action of SP on Staphylococci and skin physiopathology. qRT-PCR and direct assay of cathelicidin and human β-defensin 2 secretion also provided that demonstration that the action of SP on bacteria is independent of antimicrobial peptide expression by keratinocytes. Considering an effect of SP on S. aureus and S. epidermidis, we observed that SP increases the adhesion potential of both bacteria on keratinocytes. However, SP modulates the virulence of S. aureus and S. epidermidis through different mechanisms. The response of S. aureus is associated with an increase in Staphylococcal Enterotoxin C2 (SEC2) production and a reduction of exolipase processing whereas in S. epidermidis the effect of SP appears mediated by a rise in biofilm formation activity. The Thermo unstable ribosomal Elongation factor Ef-Tu was identified as the SP-interacting protein in S. aureus and S. epidermidis. SP appears as an inter-kingdom communication factor involved in the regulation of bacterial virulence and essential for skin microflora homeostasis.

Mechanism of Sleep Disturbance in Children with Atopic Dermatitis and the Role of the Circadian Rhythm and Melatonin

Sleep disturbance is common in children with atopic dermatitis (AD). It is a major factor leading to impaired quality of life in these patients and could have negative effects on neurocognitive function and behavior. However, the pathophysiology of sleep disturbance in children with AD is poorly understood, and there is no consensus on how to manage sleep problems in these patients. Pruritus and scratching could lead to sleep disruption but is unlikely the sole etiology. The circadian rhythm of cytokines, the immune system, and skin physiology such as transcutaneous water loss and skin blood flow might also play a role. Recent studies have suggested that melatonin could also be involved due to its multiple effects on sleep, immunomodulation, and anti-oxidant ability. Environmental factors should also be considered. In this review, we summarize the current understanding of the pathophysiology of sleep disturbance in children with AD, and discuss possible therapeutic implications.

Calcitonin Gene-Related Peptide-Exposed Endothelial Cells Bias Antigen Presentation to CD4+ T Cells toward a Th17 Response

Calcitonin gene-related peptide (CGRP) is a neuropeptide with well-established immunomodulatory functions. CGRP-containing nerves innervate dermal blood vessels and lymph nodes. We examined whether CGRP regulates the outcome of Ag presentation by Langerhans cells (LCs) to T cells through actions on microvascular endothelial cells (ECs). Exposure of primary murine dermal microvascular ECs (pDMECs) to CGRP followed by coculture with LCs, responsive CD4(+) T cells and Ag resulted in increased production of IL-6 and IL-17A accompanied by inhibition of IFN-γ, IL-4, and IL-22 compared with wells containing pDMECs treated with medium alone. Physical contact between ECs and LCs or T cells was not required for this effect and, except for IL-4, we demonstrated that IL-6 production by CGRP-treated pDMECs was involved in these effects. CD4(+) cells expressing cytoplasmic IL-17A were increased, whereas cells expressing cytoplasmic IFN-γ or IL-4 were decreased by the presence of CGRP-treated pDMECs. In addition, the level of retinoic acid receptor-related orphan receptor γt mRNA was significantly increased, whereas T-bet and GATA3 expression was inhibited. Immunization at the site of intradermally administered CGRP led to a similar bias in CD4(+) T cells from draining lymph node cells toward IL-17A and away from IFN-γ. Actions of nerve-derived CGRP on ECs may have important regulatory effects on the outcome of Ag presentation with consequences for the expression of inflammatory skin disorders involving Th17 cells.

Altered manifestations of skin disease at sites affected by neurological deficit

BACKGROUND

The contribution of the nervous system to inflammation in general and inflammatory skin disease in particular has been underappreciated. It is now apparent that an intact neural component is required for the conventional clinical manifestations of many inflammatory skin diseases.

OBJECTIVES

To investigate the relationship between nerve damage and skin disease.

METHODS

Previous individual reports since 1966 were collected systematically and the clinical observations described therein were placed within current concepts of neurogenic inflammation.

RESULTS

We reviewed the literature and identified 23 cases of alterations in the appearance or distribution of skin disorders in patients with acquired central or peripheral neural damage or dysfunction. In 19 cases, near or complete resolution of pre-existing skin lesions occurred in areas directly or indirectly supplied by a subsequently injured nervous system. Exacerbation or new onset of skin lesions occurred in only four cases. The neural deficits described included damage within the peripheral or central nervous system resulting in pure sensory, pure motor or combined sensory and motor deficits.

CONCLUSIONS

These cases highlight the importance of neural innervation and neurogenic inflammation in the development of inflammatory skin disease and prompt further examination of the use of neural blockade as an adjunctive therapy in the treatment of inflammatory dermatoses.

Evoked itch perception is associated with changes in functional brain connectivity

Chronic itch, a highly debilitating condition, has received relatively little attention in the neuroimaging literature. Recent studies suggest that brain regions supporting itch in chronic itch patients encompass sensorimotor and salience networks, and corticostriatal circuits involved in motor preparation for scratching. However, how these different brain areas interact with one another in the context of itch is still unknown. We acquired BOLD fMRI scans in 14 atopic dermatitis patients to investigate resting-state functional connectivity before and after allergen-induced itch exacerbated the clinical itch perception in these patients. A seed-based analysis revealed decreased functional connectivity from baseline resting state to the evoked-itch state between several itch-related brain regions, particularly the insular and cingulate cortices and basal ganglia, where decreased connectivity was significantly correlated with increased levels of perceived itch. In contrast, evoked itch increased connectivity between key nodes of the frontoparietal control network (superior parietal lobule and dorsolateral prefrontal cortex), where higher increase in connectivity was correlated with a lesser increase in perceived itch, suggesting that greater interaction between nodes of this executive attention network serves to limit itch sensation via enhanced top-down regulation. Overall, our results provide the first evidence of itch-dependent changes in functional connectivity across multiple brain regions.

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Atopic dermatitis patients were subjected to allergen-induced itch.

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Evoked itch reduced functional connectivity between itch-related brain regions.

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Evoked itch increased functional connectivity within frontoparietal control network.

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The above changes in functional connectivity correlated with perceived itch level.

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Itch sensation may be top-down regulated by frontoparietal control network.

Risk of epilepsy among patients with atopic dermatitis: a nationwide longitudinal study

OBJECTIVE

Both atopic dermatitis and epilepsy have been regarded as chronic inflammatory diseases. However, their association has yet to be investigated.

METHODS

Using the Taiwan National Health Insurance Research Database, 35,312 patients with atopic dermatitis but without a history of epilepsy, and 35,312 age-/gender-matched controls were enrolled between 1998 and 2008, and followed to the end of 2011 to identify the development of epilepsy.

RESULTS

Subjects with atopic dermatitis had a higher incidence of developing epilepsy (0.94 vs. 0.27/1,000 person-years, p < 0.001) than the control group. The Cox regression model showed that atopic dermatitis increased the risk of developing epilepsy (hazard ratio [HR] 2.91, 95% confidence interval [CI] 2.23-3.82) after adjusting for demographic data and medical comorbidities. Sensitivity tests showed consistent findings (HR 2.32, 95% CI 1.68-2.96) after excluding the first year of observation. In addition, asthma (HR 1.34, 95% CI 1.04-1.72) and allergic rhinitis (HR 1.34, 95% CI 1.04-1.73) were related to the risk of epilepsy.

SIGNIFICANCE

Subjects with atopic dermatitis were associated with an increased risk of developing epilepsy in later life. Further studies would be needed to investigate the underlying mechanisms.

Effects of a skin neuropeptide (substance p) on cutaneous microflora

Background

Skin is the largest human neuroendocrine organ and hosts the second most numerous microbial population but the interaction of skin neuropeptides with the microflora has never been investigated. We studied the effect of Substance P (SP), a peptide released by nerve endings in the skin on bacterial virulence.

Methodology/Principal Findings

Bacillus cereus, a member of the skin transient microflora, was used as a model. Exposure to SP strongly stimulated the cytotoxicity of B. cereus (+553±3% with SP 10⁻⁶ M) and this effect was rapid (<5 min). Infection of keratinocytes with SP treated B. cereus led to a rise in caspase1 and morphological alterations of the actin cytoskeleton. Secretome analysis revealed that SP stimulated the release of collagenase and superoxide dismutase. Moreover, we also noted a shift in the surface polarity of the bacteria linked to a peel-off of the S-layer and the release of S-layer proteins. Meanwhile, the biofilm formation activity of B. cereus was increased. The Thermo unstable ribosomal Elongation factor (Ef-Tu) was identified as the SP binding site in B. cereus. Other Gram positive skin bacteria, namely Staphylococcus aureus and Staphylococcus epidermidis also reacted to SP by an increase of virulence. Thermal water from Uriage-les-Bains and an artificial polysaccharide (Teflose®) were capable to antagonize the effect of SP on bacterial virulence.

Conclusions/Significance

SP is released in sweat during stress and is known to be involved in the pathogenesis of numerous skin diseases through neurogenic inflammation. Our study suggests that a direct effect of SP on the skin microbiote should be another mechanism.

Nerve-derived transmitters including peptides influence cutaneous immunology

Clinical observations suggest that the nervous and immune systems are closely related. For example, inflammatory skin disorders; such as psoriasis, atopic dermatitis, rosacea and acne; are widely believed to be exacerbated by stress. A growing body of research now suggests that neuropeptides and neurotransmitters serve as a link between these two systems. Neuropeptides and neurotransmitters are released by nerves innervating the skin to influence important actors of the immune system, such as Langerhans cells and mast cells, which are located within close anatomic proximity. Catecholamines and other sympathetic transmitters that are released in response to activation of the sympathetic nervous system are also able to reach the skin and affect immune cells. Neuropeptides appear to direct the outcome of Langerhans cell antigen presentation with regard to the subtypes of Th cells generated and neuropeptides induce the degranulation of mast cells, among other effects. Additionally, endothelial cells, which release many inflammatory mediators and express cell surface molecules that allow leukocytes to exit the bloodstream, appear to be regulated by certain neuropeptides and transmitters. This review focuses on the evidence that products of nerves have important regulatory activities on antigen presentation, mast cell function and endothelial cell biology. These activities are highly likely to have clinical and therapeutic relevance.

The practical understanding and treatment of asthma

Asthma is a syndrome which is seen by physicians in nearly every specialty and affects millions of people throughout the world. Although the geoepidemiology with respect to prevalence and incidence of asthma does vary, even under the most mild of circumstance, asthma is among the leading causes of school absenteeism, work loss, and physician visits. In the past, it was considered primarily a disorder of childhood. Hence, the adage that children outgrow their asthma. We now realize that children really only outgrow their pediatrician and the genetic predisposition to asthma and bronchial hyperactivity persists throughout life. This issue is devoted to key papers that focus on important clinical problems in allergies and asthma. This issue is dedicated to helping the many sufferers of asthma with the hope that this topic will eventually become a medical anachronism.

Expression of neuroserpin, a selective inhibitor of tissue-type plasminogen activator in the human skin

Serine protease of the fibrinolytic system and their specific inhibitors, the serine protease inhibitors (SERPINs) are implicated in a number of physiological and pathological processes in skin. The main SERPIN is the plasminogen activator inhibitor-1 (or PAI-1), which is involved in wound healing and in pathogenesis of several diseases including skin fibrosis. Another member of SERPIN superfamily, the neuroserpin (NSP), is widely expressed in the central nervous system. It has been recently detected in different organs such as pancreas, heart, kidney and testis. In this study, we provided evidences for the presence of NSP in the skin, in 10 human skin samples (HSS) at mRNA level (RT-PCR) and protein level (Western blot and immunohistochemistry). The immunohistochemistry analysis showed that this expression was located in dermis around blood vessels.

Novel challenges for the allergist

The last years have witnessed novel findings with exciting developments in the field of allergy-related diseases including asthma, bronchial hyperresponsiveness, eczema, and atopy that have enormously increased over the past few years. This issue of the Reviews is timely dedicated to comprehensive articles discussing the current trends in the study of these conditions. In particular, the impact of new data in genomics, environmental factors through epigenetics and proteomics will be reviewed and critically discussed.