Neuroimmune mechanisms in patients with atopic dermatitis during chronic stress

Prospective Clinical Study: Full-Body Blue Irradiation in the Treatment of Atopic Dermatitis

INTRODUCTION

Ultraviolet-free (UV-free) blue light phototherapy has emerged as a promising option due to its reported efficacy and minimal adverse effects. This study aims to evaluate the effectiveness of full-body blue light irradiation in both adult and pediatric patients with atopic dermatitis (AD), assessing its impact on skin condition and mood regulation by investigating serum concentrations of serotonin and kynurenine pathway metabolites.

METHODS

20 patients (age 9-45) with moderate and severe AD were included in the study. Treatment consisted of 10 irradiations with Full Body Blue device (453 nm). Serum concentrations of serotonin, quinolinic acid, kynurenic acid, tryptophan, and kynurenine were measured before and after irradiations.

RESULTS

After 10 sessions of full blue light therapy (453 nm) statistically significant improvements were observed in Eczema Area Severity Index (EASI 13.16 vs. 8.65; p = 0.00016), SCORing Atopic Dermatitis (SCORAD 44.99 vs. 23.73; p < 0.00001), Visual Analogue Scale (VAS 6.53 vs. 3.95; p = 0.00251), 10-item pruritus severity scale (13.32 vs. 7.05; p < 0.00001). Moreover, statistically significant decrease in Dermatology Life Quality Index (DLQI) was noted (14.37 vs. 7.42; p = 0.00351). Additionally, increase in the serum concentration of serotonin was observed after completing 10 irradiation sessions (median 139.77 mg/ml vs. 274.92 mg/ml; p < 0.00001).

CONCLUSION

Blue light may be a promising and safe treatment in patients with AD. It might also positively influence mood. Further investigations are needed to confirm those findings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT06516783.

Microbial perspective on the skin-gut axis and atopic dermatitis

Atopic dermatitis (AD) is a relapsing inflammatory skin condition that has become a global health issue with complex etiology and mounting prevalence. The association of AD with skin and gut microbiota has been revealed by virtue of the continuous development of sequencing technology and genomics analysis. Also, the gut-brain-skin axis and its mutual crosstalk mechanisms have been gradually verified. Accordingly, the microbiota-skin-gut axis also plays an important role in allergic skin inflammation. Herein, we reviewed the relationship between the microbiota-skin-gut axis and AD, explored the underlying signaling molecules and potential pathways, and focused on the potential mechanisms of probiotics, antimicrobial peptides (AMPs), coagulase-negative staphylococci transplantation, fecal microbiota transplantation, AMPs, and addition of essential fatty acids in alleviating AD, with the aim to provide a new perspective for targeting microbiota in the treatment of allergic skin inflammation.

Immunomodulatory and anti-angiogenesis effects of excavatolide B and its derivatives in alleviating atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin condition primarily driven by T helper 2 (Th2) cytokines, resulting in skin barrier defects, angiogenesis, and inflammatory responses. The marine natural product excavatolide B (EXCB), isolated from the Formosan Gorgonian coral Briareum stechei, exhibits anti-inflammatory and analgesic properties. To enhance solubility, EXCB is chemically modified into the derivatives EXCB-61 salt and EXCB-79. The study aims to investigate the therapeutic effects of these compounds on dinitrochlorbenzene (DNCB)-induced skin damage and to elucidate the underlying anti-inflammatory and anti-angiogenesis mechanism. In vitro, using lipopolysaccharide (LPS)-induced RAW 264.7 cells, all compounds at 10 μM significantly inhibited expression of inflammatory proteins (inducible nitric oxide synthase and cyclooxygenase-2), vascular endothelial growth factor (VEGF), and cytokines (interleukin (IL)-1β, IL-6, and IL-17A). In vivo, topical application of these compounds on DNCB-induced AD mice alleviated skin symptoms, reduced serum levels of IgE, IL-4, IL-13, IL-17, and interferon-γ, and moderated histological phenomena such as hyperplasia, inflammatory cell infiltration, and angiogenesis. The three compounds restored the expression of skin barrier-related proteins (loricrin, filaggrin, and claudin-1) and reduced the expression of angiogenesis-related proteins (VEGF and platelet endothelial cell adhesion molecule-CD31) in the tissues. This is the first study to indicate that EXCB, EXCB-61 salt, and EXCB-79 can treat AD disease by reducing inflammation and angiogenesis. Hence, they may be considered potential candidates for the development of new drugs for AD.

Skin and Psychosomatics - Psychodermatology today

Modern psychodermatology relies on the bio-psycho-social disease model in psychosomatics, according to which biological, psychological and social factors (on various levels, from molecules to the biosphere) play a major role in the disease pathogenesis through complex, non-linear interactions over the entire disease course. It is nowadays experimentally proven that "emotions get into the skin". Recent research shows close anatomical, physiological and functional connections between skin and nervous system, already known to be ontogenetically related. These connections are reflected in many skin diseases where psychological and somatic etiological factors are closely intertwined. A holistic approach by the physician should do justice to this interdependence; biological, psychological and social factors should be adequately taken into account when taking anamnesis, making a diagnosis and choosing a therapy. The "visibility" of the skin organ bestows dermatology a special position among the various other clinical subjects, and renders a holistic, psychosomatic approach to the patient that is particularly important. The life course belongs also to modern psychodermatological approaches. Based on the modern psychodermatology concept, other corresponding sub-areas such as psychogastroenterology, psychocardiology etc. have emerged. After the theoretical part of this article, some selected skin diseases are discussed in more detail from the psychosomatic point of view.

Therapeutic responses to Roseomonas mucosa in atopic dermatitis may involve lipid-mediated TNF-related epithelial repair

Dysbiosis of the skin microbiota is increasingly implicated as a contributor to the pathogenesis of atopic dermatitis (AD). We previously reported first-in-human safety and clinical activity results from topical application of the commensal skin bacterium Roseomonas mucosa for the treatment of AD in 10 adults and 5 children older than 9 years of age. Here, we examined the potential mechanism of action of R. mucosa treatment and its impact on children with AD less than 7 years of age, the most common age group for children with AD. In 15 children with AD, R. mucosa treatment was associated with amelioration of disease severity, improvement in epithelial barrier function, reduced Staphylococcus aureus burden on the skin, and a reduction in topical steroid requirements without severe adverse events. Our observed response rates to R. mucosa treatment were greater than those seen in historical placebo control groups in prior AD studies. Skin improvements and colonization by R. mucosa persisted for up to 8 months after cessation of treatment. Analyses of cellular scratch assays and the MC903 mouse model of AD suggested that production of sphingolipids by R. mucosa, cholinergic signaling, and flagellin expression may have contributed to therapeutic impact through induction of a TNFR2-mediated epithelial-to-mesenchymal transition. These results suggest that a randomized, placebo-controlled trial of R. mucosa treatment in individuals with AD is warranted and implicate commensals in the maintenance of the skin epithelial barrier.

Advances in Understanding the Initial Steps of Pruritoceptive Itch: How the Itch Hits the Switch

Pruritoceptive (dermal) itch was long considered an accompanying symptom of diseases, a side effect of drug applications, or a temporary sensation induced by invading pruritogens, as produced by the stinging nettle. Due to extensive research in recent years, it was possible to provide detailed insights into the mechanism of itch mediation and modulation. Hence, it became apparent that pruritus is a complex symptom or disease in itself, which requires particular attention to improve patients’ health. Here, we summarize recent findings in pruritoceptive itch, including how this sensation is triggered and modulated by diverse endogenous and exogenous pruritogens and their receptors. A differentiation between mediating pruritogen and modulating pruritogen seems to be of great advantage to understand and decipher the molecular mechanism of itch perception. Only a comprehensive view on itch sensation will provide a solid basis for targeting this long-neglected adverse sensation accompanying numerous diseases and many drug side effects. Finally, we identify critical aspects of itch perception that require future investigation.

Evaluation of Efficacy of Mirtazapine on Pruritus and Serum Histamine and Serotonin Levels in Patients Undergoing Hemodialysis: A Before-After Pilot Clinical Trial

Background

Although chronic kidney disease-associated pruritus (CKD-aP) remains a frequent and frustrating symptom in patients with advanced kidney diseases, its optimal treatments are not well defined. Based on its mechanism of action, as a histamine-1 (H1), 5-(hydroxytryptamine) HT2, and 5HT3-receptor blocker, mirtazapine may be effective in the treatment of CKD-aP. Hence, this study aimed to investigate the efficacy of mirtazapine for the treatment of pruritus in patients undergoing hemodialysis (HD).

Methods

A before-after clinical trial was conducted from September 2018 until March 2019, on 30 HD-patients that had been referred to the HD ward of a tertiary hospital, in Hamadan, Iran. After the 2-week washout period, mirtazapine was administered with a dosage of 15 mg/day for an additional 2 weeks. At baseline and at each dialysis session, the effects of the mirtazapine on the pruritus severity based on the visual analogue scale (VAS) and degree of sleep interference resulting from the pruritus were asked and recorded. Additionally, at the baseline and the end of 2 weeks of treatment, the serum histamine and serotonin levels, as the main chemical pruritogens evoking pruritus symptoms, were also determined.

Results

Twenty-seven patients completed the entire course of the study. Based on the general linear model analysis, a progressive decline in the mean VAS score was observed over time during the study. The mean VAS score decreased from 8.48 ± 1.01 at baseline to 1.04 ±0.79 at the end of treatment (P-value<0.001). Similarly, the mean sleep interference scores were also significantly improved throughout treatment (decreased from 8.07±1.43 to 2.81± 0.74; P-value<0.001). Further, at the end of the treatment, a noticeable decrement in the serum histamine level was also seen (P-value = 0.006). The drug was acceptably well-tolerated and a majority of the patients were satisfied with this treatment.

Conclusion

This pilot study suggests that mirtazapine may be an effective treatment option for the management of CKD-aP. However, further studies would be needed to confirm these results.

Effect of mirtazapine on pruritus in patients on hemodialysis: a cross-over pilot study

BACKGROUND

Uremic pruritus (UP) is a highly prevalent and disturbing problem in patients with advanced chronic kidney disease (CKD); however, treatment of UP is largely unsatisfactory. The present study was designed to investigate the effectiveness of mirtazapine, an atypical antidepressant agent with potent antagonistic activity against serotonin (5HT2, 5HT3) and histamine (H1) receptors, in the treatment of pruritus in hemodialysis (HD) patients.

METHODS

An 8-week long, prospective, open-label, and cross-over randomized clinical trial study was conducted on 77 HD patients with chronic pruritus. After a 2-week washout period, eligible patients were randomly assigned either to the mirtazapine (15 mg per day) or gabapentin (100 per day) for 2 weeks. Following 2 weeks washout period, subjects crossed over to the other treatment arm for 2 more weeks. The severity of pruritus was measured seven times during each treatment period using the visual analogue scale (VAS). Furthermore, at the end of the study, patients also were blindly asked which treatment (first or last in the sequential course of the study) they preferred.

RESULTS

Sixty-one patients completed two treatment periods of the study. Although, compared to baseline, both gabapentin and mirtazapine treatment resulting in significant improvement in VAS scores, decreasing in pruritus severity was significantly greater in the mirtazapine treatment period compared with the gabapentin treatment period (P < 0.001). Furthermore, although side effects such as drowsiness and dry mouth more reported in the mirtazapine treatment period, overall higher percentage of the study patients preferred mirtazapine over gabapentin for the treatment of their pruritus symptoms.

CONCLUSIONS

Although preliminary, our study provides evidence that mirtazapine can be an effective therapy for UP in patients who are on maintenance HD. However, further studies would be necessary to confirm effectiveness as well as the safety of mirtazapine in the long-term management of chronic pruritus.

Atopic Dermatitis and Comorbidity

Atopic dermatitis is the most common chronic inflammatory skin disease. It is often the first indicator of allergic diseases, and a certain percentage of patients are affected by allergic rhinitis and/or asthma as a consequence. The study aimed to investigate the link between atopic dermatitis and comorbidity in family medicine. In the specialist family medicine practice Osijek, a retrospective study was conducted in the period from January 1, 2016 to July 1, 2017 on the percentage of patients with atopic dermatitis in the total number of patients, and their comorbid diseases. The data source was the E-chart. The results showed that 195 (10.53%) out of 2056 patients had atopic dermatitis, 80 (41%) patients had atopic dermatitis and allergic rhinitis, 34 (17.4%) asthma, 132 (67.7%) infections, 59 (30.3%) gastrointestinal disturbances, and 68 (34.3%) had mental disorders. Patients up to 18 years old were more likely to have infections, and adult patients were exposed to chronic stress. The most commonly used drug was loratadine (60.5%), while mometasone was the most commonly administered topical drug (40%). The result of this research showed the steps of the ˝atopic march˝. Atopic dermatitis is followed by changes in the skin and its progression to other organ systems in most of the patients.

Serotonin Expression in Lichen Planus Lesions and Its Relationship with Depression/Anxiety

Background

Psychological factors such as stress, depression, and anxiety have been documented to contribute to the development of lesions in lichen planus (LP).

Objective

To evaluate the relationship between serotonin expression in LP lesions and depression/anxiety.

Methods

Forty patients (22 females, 18 males) with LP and 20 healthy control subjects were included in this study. The severity of LP was assessed with the palmar method (using the measurement of affected body surface area [BSA]). The depression and anxiety scores were measured with Beck's depression inventory (BDI) and Beck's anxiety inventory (BAI). The expression of serotonin was determined via immunohistochemistry in LP lesions and in the control group skin using a monoclonal antibody to serotonin.

Results

The skin biopsies of the LP patients had significantly higher levels of serotonin than those of the control subjects (p<0.001). In the LP patients, and there was a positive correlation between serotonin expression and LP severity (p=0.022). Based on the results from the BDI and BAI, there was a significant relationship between the severity of depression/anxiety and intensity of serotonin expression (p<0.001).

Conclusion

Data from this study suggest that serotonin may have a possible role in the pathogenesis of LP. Further, the relationship between serotonin expression in acute cutaneous lesions and the depression/anxiety scores indicates that serotonin may be a mediator for the association of LP and depression/anxiety simultaneously. There is a need for more specific studies showing the expression of serotonin in the lichen planus to demonstrate the cause or effect.

Tachykinin upregulation in atopic dermatitis

Context: Atopic dermatitis (AD) is a chronic, inflammatory, itching skin disorder, which may worsen due to stress, depression and anxiety. Tachykinins may be involved in inflammation signaling as well as they may have a role in stress, depression and anxiety. Objective: This study aimed to measure the expression of tachykinin markers, in the skin of patients with AD, and the correlation of these tachykinins with clinical and psychodemographic parameters. Materials and methods: Twenty-eight adult patients with AD were investigated regarding tachykinin expression in skin biopsies, using an immunohistochemical technique. The patients were characterized with clinical and psychodemographic parameters. Results: The number of substance P and neurokinin (NK)A positive nerve fibers, as well as NKA positive mononuclear dermal cells, was increased in lesional compared to non-lesional skin. Interestingly, the depression score and the number of dermal NK-1 receptor (R) positive cells in lesional as well as in non-lesional skin showed a correlation. Conclusion: These findings indicate an upregulation of the tachykinergic system in the inflamed skin of AD.

Feline Interstitial Cystitis Enhances Mucosa-Dependent Contractile Responses to Serotonin

PURPOSE

To determine whether responses to serotonin are altered in bladder strips from cats diagnosed with a naturally occurring form of bladder pain syndrome/interstitial cystitis termed feline interstitial cystitis (FIC).

METHODS

Full thickness bladder strips were isolated from aged matched healthy control cats and cats with clinically verified FIC. Bladder strips were mounted in an organ bath and connected to a tension transducer to record contractile activity. A serotonin dose response (0.01-10μM) was determined for each strip with the mucosa intact or denuded.

RESULTS

Bladder strips from control and FIC cats contracted in response to serotonin in a dose-dependent manner. The normalized force of serotonin-evoked contractions was significantly greater in bladder strips from cats with FIC (n=7) than from control cats (n=4). Removal of the mucosa significantly decreased serotonin-mediated responses in both control and FIC bladder preparations. Furthermore, the contractions in response to serotonin were abolished by 1μM atropine in both control and FIC bladder strips.

CONCLUSION

The effect of serotonin on contractile force, but not sensitivity, was potentiated in bladder strips from cats with FIC, and was dependent upon the presence of the mucosa in control and FIC groups. As atropine inhibited these effects of serotonin, we hypothesize that, serotonin enhances acetylcholine release from the mucosa of FIC cat bladder strips, which could account for the increased force generated. In summary, FIC augments the responsiveness of bladder to serotonin, which may contribute to the symptoms associated with this chronic condition.

Association between Stress and the HPA Axis in the Atopic Dermatitis

The hypothalamic–pituitary–adrenal (HPA) axis is one of the body’s neuroendocrine networks that responds to psychological stress (PS). In the skin, there exists a peripheral HPA axis similar to the central axis. Glucocorticoids (GCs) are key effector molecules of the HPA axis and are essential for cutaneous homeostasis. Atopic dermatitis (AD) is a condition typically characterized by a chronic relapsing course that often results in PS. HPA dysfunction is present in AD patients by the decreased response of GCs elevation to stress as compared to those unaffected by AD. Nevertheless, in skin, acute PS activates several metabolic responses that are of immediate benefit to the host. During the acute phase of PS, increased endogenous GCs have been shown to provide benefit rather than by aggravating cutaneous inflammatory dermatoses. However, a chronic T helper cell type 2 (Th2) predominant cytokine profile acts as a negative feedback loop to blunt the HPA axis response in AD. In this article, we reviewed the role of CRF, pro-opiomelanocortin (POMC)-derived peptides, GCs of the HPA, and 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in AD, with a discussion of the pathogenetic mechanisms of inflammation and skin barrier functions, including antimicrobial defense, and their association with PS.

Immunohistochemical Evaluation of Role of Serotonin in Pathogenesis of Psoriasis

INTRODUCTION

Psoriasis is a common skin disorder characterized by erythaematosquamous papules and plaques. It is known to be associated with stressful and depressive disorders. Serotonin is a neurotransmitter that plays a role in the pathogenesis of inflammatory skin disorders.

AIM

To evaluate the role of serotonin in pathogenesis of psoriasis.

MATERIALS AND METHODS

Using standard immunohistochemical techniques, 24 biopsies from patients with chronic plaque psoriasis were examined together with 12 biopsies from age and gender-matched healthy subjects as a control group.

RESULTS

Both the percentage of positive cells (p=0.018) and H-score values (p=0.015) of serotonin expression were significantly higher in psoriasis compared to normal skin. H score of serotonin expression was significantly higher in cases with totally absent Granular Cell Layer (GCL) as opposed to those with thin/focally absent GCL (p=0.011), and in cases with moderate/strong epidermal inflammation compared to cases with mild inflammation (p=0.035). No significant correlation was detected between H score of cases and age, disease duration or Psoriasis Area and Severity Index (PASI) score.

CONCLUSION

Serotonin might play a role in development of psoriasis through its role as a growth factor promoting keratinocyte proliferation, and as mediator of inflammation and stimulant of T cell activation. It recruits T cells to sites of cutaneous inflammation and potentiate macrophage accessory function for T cell activation. Its expression is not related to the disease severity. Future large-scaled research on population of different ethnicities including other disease variants is needed. The use of serotonin receptor antagonists and serotonin reuptake inhibitors may be evaluated on wide-based studies to put the current observation into action.

Mental stress in atopic dermatitis--neuronal plasticity and the cholinergic system are affected in atopic dermatitis and in response to acute experimental mental stress in a randomized controlled pilot study

Rationale

In mouse models for atopic dermatitis (AD) hypothalamus pituitary adrenal axis (HPA) dysfunction and neuropeptide-dependent neurogenic inflammation explain stress-aggravated flares to some extent. Lately, cholinergic signaling has emerged as a link between innate and adaptive immunity as well as stress responses in chronic inflammatory diseases. Here we aim to determine in humans the impact of acute stress on neuro-immune interaction as well as on the non-neuronal cholinergic system (NNCS).

Methods

Skin biopsies were obtained from 22 individuals (AD patients and matched healthy control subjects) before and after the Trier social stress test (TSST). To assess neuro-immune interaction, nerve fiber (NF)-density, NF-mast cell contacts and mast cell activation were determined by immunohistomorphometry. To evaluate NNCS effects, expression of secreted mammal Ly-6/urokinase-type plasminogen activator receptor-related protein (SLURP) 1 and 2 (endogenous nicotinic acetylcholine receptor ligands) and their main corresponding receptors were assessed by quantitative RT-PCR.

Results

With respect to neuro-immune interaction we found higher numbers of NGF+ dermal NF in lesional compared to non-lesional AD but lower numbers of Gap43+ growing NF at baseline. Mast cell-NF contacts correlated with SCORAD and itch in lesional skin. With respect to the NNCS, nicotinic acetylcholine receptor α7 (α7nAChR) mRNA was significantly lower in lesional AD skin at baseline. After TSST, PGP 9.5+ NF numbers dropped in lesional AD as did their contacts with mast cells. NGF+ NF now correlated with SCORAD and mast cell-NF contacts with itch in non-lesional skin. At the same time, SLURP-2 levels increased in lesional AD skin.

Conclusions

In humans chronic inflammatory and highly acute psycho-emotional stress interact to modulate cutaneous neuro-immune communication and NNCS marker expression. These findings may have consequences for understanding and treatment of chronic inflammatory diseases in the future.

Chronic stress suppresses the expression of cutaneous hypothalamic-pituitary-adrenocortical axis elements and melanogenesis

Chronic stress can affect skin function, and some skin diseases might be triggered or aggravated by stress. Stress can activate the central hypothalamic–pituitary–adrenocortical (HPA) axis, which causes glucocorticoid levels to increase. The skin has HPA axis elements that react to environmental stressors to regulate skin functions, such as melanogenesis. This study explores the mechanism whereby chronic stress affects skin pigmentation, focusing on the HPA axis, and investigates the role of glucocorticoids in this pathway. We exposed C57BL/6 male mice to two types of chronic stress, chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS). Mice subjected to either stress condition showed reduced melanogenesis. Interestingly, CRS and CUMS triggered reductions in the mRNA expression levels of key factors involved in the HPA axis in the skin. In mice administered corticosterone, decreased melanin synthesis and reduced expression of HPA axis elements were observed. The reduced expression of HPA axis elements and melanogenesis in the skin of stressed mice were reversed by RU486 (a glucocorticoid receptor antagonist) treatment. Glucocorticoids had no significant inhibitory effect on melanogenesis in vitro. These results suggest that, high levels of serum corticosterone induced by chronic stress can reduce the expression of elements of the skin HPA axis by glucocorticoid-dependent negative feedback. These activities can eventually result in decreased skin pigmentation. Our findings raise the possibility that chronic stress could be a risk factor for depigmentation by disrupting the cutaneous HPA axis and should prompt dermatologists to exercise more caution when using glucocorticoids for treatment.

Neuroimmunological mechanism of pruritus in atopic dermatitis focused on the role of serotonin

Although pruritus is the critical symptom of atopic dermatitis that profoundly affect the patients' quality of life, controlling and management of prurirtus still remains as unmet needs mainly due to the distinctive multifactorial pathogenesis of pruritus in atopic dermatitis. Based on the distinct feature of atopic dermatitis that psychological state of patients substantially influence on the intensity of pruritus, various psychotropic drugs have been used in clinic to relieve pruritus of atopic dermatitis patients. Only several psychotropic drugs were reported to show real antipruritic effects in atopic dermatitis patients including naltrexone, doxepin, trimipramine, bupropion, tandospirone, paroxetine and fluvoxamine. However, the precise mechanisms of antipruritic effect of these psychotropic drugs are still unclear. In human skin, serotonin receptors and serotonin transporter protein are expressed on skin cells such as keratinocytes, melanocytes, dermal fibroblasts, mast cells, T cells, natural killer cells, langerhans cells, and sensory nerve endings. It is noteworthy that serotonergic drugs, as well as serotonin itself, showed immune-modulating effect. Fenfluramine, fluoxetine and 2, 5-dimethoxy-4-iodoamphetamine significantly decreased lymphocyte proliferation. It is still questionable whether these serotonergic drugs exert the immunosuppressive effects via serotonin receptor or serotonin transporter. All these clinical and experimental reports suggest the possibility that antipruritic effects of selective serotonin reuptake inhibitors in atopic dermatitis patients might be at least partly due to their suppressive effect on T cells. Further studies should be conducted to elucidate the precise mechanism of neuroimmunological interaction in pruritus of atopic dermatitis.

Longitudinal associations between infections and atopic disorders across childhood and dysregulated adrenocortical functioning in early adolescence

The present study sought to determine if exposure to common childhood medical problems (i.e., infections and atopic disorders [e.g., allergies, asthma]) may dysregulate the hypothalamic-pituitary-adrenal (HPA) axis. Longitudinal data from 96 youth were used to examine this possibility. Medical records were drawn from government databases indicating the frequency of visits to healthcare facilities for infections and atopic disorders from infancy to early adolescence. During early adolescence, participants provided salivary cortisol samples from awakening until bedtime over 2 consecutive days. Individuals with a history of increased number visits for infections across childhood displayed elevated levels of cortisol at awakening whereas individuals with childhood histories of visits for atopic disorders displayed blunted diurnal cortisol slopes. These findings build on previous research documenting associations between infections and atopic disorders and cortisol by identifying longitudinal linkages from early health problems to later HPA axis functioning.

Chronic mild stress modulates 5-HT1A and 5-HT2A receptor expression in the cerebellar cortex of NC/Nga atopic-like mice

Atopic eczema symptoms may worsen due to stress. In the present study, the cerebellar cortex of the atopic-like mouse NC/Nga was studied regarding the effect of chronic mild stress on expression of two well-characterized serotonergic receptors (R), 5-HT1A and 5-HT2A. In total 24 mice were used. Sixteen of these mice were subjected to unpredictable stressors for 12 weeks, and 8 mice were used as controls. In order to evoke an eczema, a mite antigen was applied to 16 mice from week 9 of the experiment. Thus, three groups of mice, stressed eczematous (SE), non-stressed eczematous (NSE) and stressed control (SC), respectively, were obtained. The expression of the 5-HT1AR was analyzed using quantitative immunohistochemistry. For evaluation of 5-HT2AR a semi-quantitative technique was used, the cell density and signal intensity being measured. The highest average value for 5-HT1AR expression, in the Purkinje cells, was recorded in the NSE group, while the lowest average was in the SC group. 5-HT1AR expression differed significantly between the groups. The highest average value for density of 5-HT2AR positive Purkinje cells was evident in the SE group, while the lowest was in the SC group, this difference between groups also being statistically significant. In addition, the signal intensity was highest in the SE group, with a difference compared to the other groups. In conclusion, chronic mild stress modulates serotonergic receptor expressions in the cerebellar cortex of atopic-like mice.

Psychological Stress and the Cutaneous Immune Response: Roles of the HPA Axis and the Sympathetic Nervous System in Atopic Dermatitis and Psoriasis

Psychological stress, an evolutionary adaptation to the fight-or-flight response, triggers a number of physiological responses that can be deleterious under some circumstances. Stress signals activate the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system. Elements derived from those systems (e.g., cortisol, catecholamines and neuropeptides) can impact the immune system and possible disease states. Skin provides a first line of defense against many environmental insults. A number of investigations have indicated that the skin is especially sensitive to psychological stress, and experimental evidence shows that the cutaneous innate and adaptive immune systems are affected by stressors. For example, psychological stress has been shown to reduce recovery time of the stratum corneum barrier after its removal (innate immunity) and alters antigen presentation by epidermal Langerhans cells (adaptive immunity). Moreover, psychological stress may trigger or exacerbate immune mediated dermatological disorders. Understanding how the activity of the psyche-nervous -immune system axis impinges on skin diseases may facilitate coordinated treatment strategies between dermatologists and psychiatrists. Herein, we will review the roles of the HPA axis and the sympathetic nervous system on the cutaneous immune response. We will selectively highlight how the interplay between psychological stress and the immune system affects atopic dermatitis and psoriasis.

Psychoneuroimmunology of psychological stress and atopic dermatitis: pathophysiologic and therapeutic updates

Atopic dermatitis is a chronic inflammatory skin disease characterized by impaired epidermal barrier function, inflammatory infiltration, extensive pruritus and a clinical course defined by symptomatic flares and remissions. The mechanisms of disease exacerbation are still poorly understood. Clinical occurrence of atopic dermatitis is often associated with psychological stress. In response to stress, upregulation of neuropeptide mediators in the brain, endocrine organs, and peripheral nervous system directly affect immune and resident cells in the skin. Lesional and non-lesional skin of patients with atopic dermatitis demonstrates increased mast cells and mast cell-nerve fiber contacts. In the setting of stress, sensory nerves release neuromediators that regulate inflammatory and immune responses, as well as barrier function. Progress towards elucidating these neuroimmune connections will refine our understanding of how emotional stress influences atopic dermatitis. Moreover, psychopharmacologic agents that modulate neuronal receptors or the amplification circuits of inflammation are attractive options for the treatment of not only atopic dermatitis, but also other stress-mediated inflammatory skin diseases.

Polymorphisms in the serotonin transporter gene of patients with atopic dermatitis-association with personality traits related to high level of anxiety

CONTEXT

The symptoms of atopic dermatitis (AD) are often aggravated by anxiety, and the serotonin transporter (5-HTT) has been shown to be of importance in this context. Three polymorphisms affecting transcription of this gene are known: a repetitive element, in the promoter region (5HTTLPR), a variable number tandem repeats (VNTR) within intron 2 referred to as STin2, and a single-nucleotide (A/G) polymorphism (SNP) located within the 5-HTTLPR.

OBJECTIVE

To examine for possible relationships between these polymorphisms and aggravation of AD by stress.

MATERIALS AND METHODS

Thirty-three patients with a history of such aggravation, together with 33 age- and gendermatched healthy control subjects, were recruited. The Karolinska Scales of Personality questionnaire was employed to evaluate anxiety-related personality traits and genomic DNA was extracted from blood samples and analyzed using the polymerase chain reaction.

RESULTS

Although the prevalence of the short and long alleles of 5-HTTLPR did not differ between the patients and healthy controls, there was a tendency towards high prevalence of the short (10-copy) variant of STin2 among the patients. When the study population was further analysed by subdivision into subgroups all AD patients with high- anxiety traits carried the short variant of STin2. In the corresponding healthy control group, the prevalences of the 10-and 12-copy variants were 62% and 38%, respectively (P < 0.01).

CONCLUSION

These findings indicate a possible association between the 10-copy variant of STin2 and aggravation of AD by anxiety.

Serotonin-mediated tuning of human helper T cell responsiveness to the chemokine CXCL12

In addition to its role as neurotransmitter, serotonin (5-HT) is an important modulator of inflammation and immunity. Here, we report novel findings suggesting a 5-HT involvement in T cell migration. In particular, we show that 5-HT tunes the responsiveness of human T lymphocytes to the broadly expressed chemokine CXCL12 in transwell migration assays. By real-time PCR, western blot analysis and electrophysiological patch clamp experiments, we demonstrate that the type 3 5-HT receptor (5-HT₃) is functionally expressed in human primary T cells. In addition, specific 5-HT₃ receptor agonists selectively decrease T cell migration towards gradients of CXCL12 but not of inflammatory chemokines, such as CCL2 and CCL5. In transmigration experiments, 5-HT₃ receptor stimulation reverts the inhibitory effect of endothelial-bound CXCL12 on T cell migration. Our data suggest that the reduced T cell responsiveness to CXCL12 induced by 5-HT may occur to facilitate T cell extravasation and migration into inflamed tissues.

Time-dependent modulation of serotonin and its receptors 1A and 2A expression in allergic contact dermatitis

BACKGROUND

Serotonin implication in allergic contact dermatitis was earlier suggested.

OBJECTIVE

To study the expression of serotonin (5-HT) and its receptors 1A and 2A during the kinetics of allergic contact dermatitis (ACD).

METHOD

Biopsies from 10 female nickel-allergic patients were obtained at 0, 6, 24, 48 and 72 h after nickel application using a patch testing procedure and then analysed by immunohistochemistry.

RESULTS

Higher 5-HT epidermal immunoreactivity was seen at 0 and 6 h compared with 24, 48 and 72 h. The number of 5-HT labelled platelets was higher at 48 and 72 h compared with 0, 6 and 24 h. There was a decrease in the number of 5-HT1AR positive cells at 24, 48 and 72 h compared with 0 h. Furthermore, epidermal 5-HT1AR immunoreactivity was stronger at 48 and 72 h compared with 0 h. Total (dermis plus epidermis) number of 5-HT2AR positive cells was gradually increased in a time-dependent manner at 6, 24, 48 and 72 h compared with 0 h.

CONCLUSIONS

Our results suggest the implication of 5-HT, 5-HT1AR and 5-HT2AR in the development of human ACD and the possibility to target those receptors at an early stage of this inflammatory condition.

Children with Atopic Dermatitis Do Not Have More Anxiety or Different Cortisol Levels Compared with Normal Children

Background:

The hypothalamic-pituitary-adrenal axis has an important immunoregulatory role under stress, and stressmediated anxiety has been reported to be associated with alterations in immune functions and attenuated cortisol levels in atopic dermatitis (AD) patients.

Objective:

We investigated serum basal cortisol and anxiety levels in pediatric AD patients and compared them with those of controls.

Methods:

Basal serum cortisol levels were measured in 36 pediatric AD patients (aged 9–16 years) and 36 control subjects (aged 9–15 years). Anxiety was assessed by the trait anxiety subscale (TAI-C) of the State-Trait Anxiety Inventory for Children. The severity of AD was assessed by the objective severity scoring of AD (SCORing Atopic Dermatitis [SCORAD]).

Results:

Data analysis showed no statistical difference for the basal serum cortisol levels ( p = .383) and the TAI-C ( p = .730) between the two groups. No significant correlation was found between the basal cortisol values and the TAI-C scores in the AD group ( p = .290). The SCORAD index was correlated with the TAI-C scores ( p < .05) but not correlated with the basal serum cortisol values in AD patients ( p = .06).

Conclusion:

Children with AD do not have more anxiety or different cortisol levels when compared with normal children, but the severe symptomatology of AD itself may cause anxiety levels to increase in children with AD.

Current concepts in psychodermatology

Dermatology is a discipline in which psychosomatic issues serve a key purpose in helping us understand the etiology and progression of skin diseases and determining appropriate treatment protocols. Emotional factors appear to significantly influence most skin diseases, and the correlation between stressful life events and disease flares is well recognized in dermatology. In this article, recent research is highlighted for major cutaneous disease states, as well as psychiatric disorders with symptoms that present as skin disorders. The role of the expanding field of psychoneuroimmunology as it pertains to dermatologic disorders is discussed. The author also presents recommendations for optimal evaluation and management of psychosocial concerns in the dermatology patient population.

The serotonin transporter protein is expressed in psoriasis, where it may play a role in regulating apoptosis

Since the symptoms of psoriasis may be changed by treatment with selective serotonin reuptake inhibitors (SSRIs), the expression of serotonin (5-HT) and its transporter protein (SERT) in the skin of patients with psoriasis were examined employing a biotinylated-streptavidine procedure. In biopsies of such skin staining for 5-HT was limited to platelets; the expression of SERT in the keratinocytes of involved regions was redistributed; the numbers of SERT-positive dendritic or round mononuclear cells in the epidermis of involved psoriatic skin were higher than in normal healthy control skin; and the dermis of the involved skin contained higher numbers of round inflammatory cells immunostained for SERT than either non-involved psoriatic skin or normal skin. Double-immunostaining indicated that the skin cells expressing SERT also expressed CD1a, CD3 or tryptase. In addition, SERT immunostaining was co localized with caspase-3, a key regulator of apoptosis, but not with TUNEL staining. The present findings indicate that SERT might play a role in regulating apoptosis in inflammatory cells associated with psoriasis, in which case this protein might constitute a valuable therapeutic target.