A Staphylococcus epidermidis strain inhibits the uptake of Staphylococcus aureus derived from atopic dermatitis skin into the keratinocytes.

BACKGROUND: Various bacterial species form a microbiome in the skin. In the past, dead Staphylococcus aureus derived from atopic dermatitis (AD) are taken up by keratinocytes; however, whether live S. aureus can be taken up by keratinocytes is unknown. OBJECTIVE: This study aimed to examine whether live AD strains of S. aureus internalize into the keratinocytes and how the internalization changes under conditions in which other bacterial species including S. epidermidis are present. METHODS: HaCaT cells were cultured with live S. aureus and S. epidermidis (live or heat-treated) or their culture supernatants. After coculture, the change in the amount of S. aureus in the cytoplasm of HaCaT cells was analyzed using, a high-throughput imaging system, Opera Phenix™. RESULTS: Live S. aureus were taken up in the cytoplasm of HaCaT cells. Coculturing live S. aureus with live S. epidermidis or the culture supernatants decreased the abundance of S. aureus in the cytoplasm. The heat-treated culture supernatants of live S. epidermidis or culture supernatants of other S. strains did not decrease the abundance of S. aureus in the cytoplasm. CONCLUSION: Live S. aureus was internalized into the cytoplasm of HaCaT cells as does heat-treated S. aureus. In addition, the heat-sensitive substances secreted by coculture with S. epidermidis and keratinocytes inhibited the uptake of S. aureus by keratinocytes.

Mathematical-based morphological classification of skin eruptions corresponding to the pathophysiological state of chronic spontaneous urticaria.

BACKGROUND: Chronic spontaneous urticaria (CSU) is one of the most intractable human-specific skin diseases. However, as no experimental animal model exists, the mechanism underlying disease pathogenesis in vivo remains unclear, making the establishment of a curative treatment challenging. METHODS: A novel approach combining mathematical modelling, in vitro experiments and clinical data analysis was used to infer the pathological state of CSU patients from geometric features of the skin eruptions. RESULTS: Based on our hierarchical mathematical modelling, the eruptions of CSU were classified into five categories, each with distinct histamine, basophils, mast cells and coagulation factors network signatures. The analysis of 105 real CSU patients with this classification by six individual dermatologists achieved 87.6% agreement. Furthermore, our network analysis revealed that the coagulation status likely determines boundary/area pattern of wheals, while the state of spontaneous histamine release from mast cells may contribute to the divergence of size and outline of the eruptions. CONCLUSIONS: Our multi-faceted approach was accurate in defining pathophysiological states of disease based on geometric features offering the potential to improve the accuracy of CSU diagnosis and better management of the disease in the clinic.

Chronic spontaneous urticaria (CSU) is a persistent skin disease that causes red itchy skin eruptions, called wheals, that are of various shapes. These wheals repeatedly appear and disappear daily for up to weeks or even decades, severely impacting the quality of life of those affected. The causes, consequences or disease processes are largely understudied. Here, we developed a novel approach using mathematical modelling to analyse the geometric measurements of patients' wheals alongside laboratory experiments on human skin samples with eruptions to improve CSU diagnosis and clinical management. We find that geometric measurements of these skin eruptions can be classified into five categories, which could facilitate accurate diagnosis and consequently better clinical management of CSU and may be more widely applied to other skin diseases.

Time Course of Priming Effect of TF Inducers on Synergistic TF Expression and Intra-Cellular Gap Formation of Human Vascular Endothelial Cells via the Extrinsic Coagulation Cascade.

Chronic spontaneous urticaria (CSU) is characterized by daily recurring wheal and flare with itch for more than 6 weeks. The extrinsic coagulation system has been shown to be activated in correlation with CSU severity. We have reported that tissue factor (TF), a trigger of the extrinsic coagulation cascade, is synergistically expressed on vascular endothelial cells by simultaneous stimulation with TF inducers (TFI), followed by activation of the extrinsic coagulation cascade and hyper permeability in vitro. However, vascular endothelial cells are not likely to be simultaneously stimulated by multiple TFIs under physiological conditions. Therefore, in order to know whether sequential, rather than simultaneous, stimuli with interval may induce synergistic activation of TF, we investigated the time course of the priming effects of each TFI for synergistic TF expression in vascular endothelial cells (HUVECs). We stimulated HUVECs with a TFI (first stimulation) and then stimulated cells with another TFI at indicated time points (second stimulation) and detected TF expression and activity. The TF expression induced by simultaneous stimulation diminished in a few hours. However, both synergistic enhancement of TF expression and activation level of the coagulation cascade were detected even when the second stimulation was added 18 or 22 h after the first stimulation. Thus, the priming effect of TFI for synergistic TF expression may persist for a half day or longer.

A single-blind, randomized, crossover study on the efficacy of icatibant for sweating-induced dermal pain (icatibant for sweating-induced dermal pain).

INTRODUCTION: Severe dermal pain triggered by sweating stimuli, such as bathing, exercise, and mental stress, significantly affects patients' daily lives. The pathomechanism underlying the sweating-induced dermal pain remains poorly understood and there exists no standard treatment for such pain. This study aims to evaluate the effectiveness of icatibant as an analgesic, a bradykinin B2 receptor antagonist, in treating sweating-induced dermal pain, and to establish the role of bradykinin in pain induction. METHODS/DESIGN: A multicenter, exploratory, crossover, single-blinded, placebo-controlled randomized, comparative study will be conducted to evaluate the efficacy of subcutaneous icatibant injection (30 mg) in treating sweating-induced dermal pain. Ten patients will be enrolled and assigned randomly in a 1:1 ratio to either the icatibant-placebo or placebo-icatibant groups. The primary endpoint is the change in the visual analog scale scores for dermal pain induced by thermal load before and after treatment with icatibant or placebo. Secondary endpoints include changes in the duration of dermal pain, blood and plasma histamine levels, serum angiotensin-converting enzyme levels, and histological evaluation of skin tissue samples at the site of dermal pain. DISCUSSION: The effectiveness of icatibant against sweating-induced dermal pain would provide clear evidence for the involvement of the bradykinin-bradykinin B2 receptor pathway in the pathogenesis of this condition. This finding may contribute to a better understanding of the underlying mechanisms of dermal pain associated with sweating stimuli and has the potential to improve patients' quality of life by suggesting potential treatment options, specifically, using drugs that inhibit bradykinin or suppress its production.

Basophil Characteristics as a Marker of the Pathogenesis of Chronic Spontaneous Urticaria in Relation to the Coagulation and Complement Systems.

Chronic spontaneous urticaria (CSU) is a common skin disorder characterized by daily or almost daily recurring skin edema and flare with itch and pruritus anywhere on the body for more than 6 weeks. Although basophil- and mast cell-released inflammatory mediators, such as histamine, play important roles in the pathogenesis of CSU, the detailed underlying mechanism is not clear. Since several auto-antibodies, IgGs which recognize IgE or the high-affinity IgE receptor (FcεRI) and IgEs against other self-antigens, are detected in CSU patients, they are considered to activate both mast cells in the skin and basophils circulating in the blood. In addition, we and other groups demonstrated that the coagulation and complement system also contribute to the development of urticaria. Here, we summarized the behaviors, markers and targets of basophils in relation to the coagulation-complement system, and for the treatment of CSU.

The expression of prolyl isomerase Pin1 is expanded in the skin of patients with atopic dermatitis and facilitates IL-33 expression in HaCaT cells.

Atopic dermatitis (AD) is attributable to both a genetic predisposition and environmental factors. Among numerous cytokines involved in the pathogenesis of AD, interleukin-33 (IL-33), reportedly escaping exocytotically in response to a scratch, is abundantly expressed in the skin tissues of patients with AD and is postulated to induce inflammatory and autoimmune responses. In this study, we first demonstrated that peptidylprolyl cis/trans isomerase, NIMA-interacting 1 (Pin1), a unique enzyme which isomerizes the proline residues of target proteins, is abundantly expressed in keratinocytes, and that the areas where it is present in the skin tissues of AD patients became expanded due to hyperkeratosis. Thus, we investigated the effects of Pin1 on the regulation of IL-33 expression using the human keratinocyte cell line HaCaT. Interestingly, silencing of the Pin1 gene or treatment with Pin1 inhibitors dramatically reduced IL-33 expressions in HaCaT cells, although Pin1 overexpression did not elevate it. Subsequently, we showed that Pin1 binds to STAT1 and the nuclear factor-kappaB (NF-κB) subunit p65. Silencing the Pin1 gene with small interfering RNAs significantly reduced the phosphorylation of p65, while no marked effects of Pin1 on the STAT1 pathway were detected. Thus, it is likely that Pin1 contributes to increased expression of IL-33 via the NF-κB subunit p65 in HaCaT cells, at least modestly. Nevertheless, further study is necessary to demonstrate the pathogenic roles of Pin1 and IL-33 in AD development.

Basophils activation of patients with chronic spontaneous urticaria in response to C5a despite failure to respond to IgE-mediated stimuli.

Urticaria is characterized by the occurrence of wheals and flares in response to vasoactive mediators, such as histamine. Various studies have suggested the involvement of basophils in the pathogenesis of chronic spontaneous urticaria (CSU). However, histamine release from peripheral basophils in response to stimuli acting on the high affinity IgE receptor (FcϵRI) is impaired in many patients with CSU (non/low responders). We previously demonstrated that tissue factor (TF)s expressed on vascular endothelial cells in response to a combination of various stimuli, such as that of histamine and lipopolysaccharide (LPS), activates the extrinsic coagulation pathway and produces anaphylatoxin, complement 5a (C5a), which then activates basophils and mast cells via the C5a receptor (C5aR). We have revealed that histamine release was induced in response to C5a and formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP), regardless of the response to anti-IgE antibody, the reduced numbers of basophils and severity of urticaria. Moreover, we found that spontaneous release of histamine ex vivo from basophils of patients with CSU is higher than that from healthy individuals. These results suggest that basophils and the complement system, which could be activated by coagulation factors, may play a critical role in the pathogenesis of CSU, especially in cases refractory to treatment involving the IgE/FcϵRI pathway.

Uptake of Staphylococcus aureus by keratinocytes is reduced by interferon-fibronectin pathway and filaggrin expression.

Staphylococcus aureus (S. aureus) is frequently detected in the skin of patients with atopic dermatitis (AD). AD skin-derived strains of S. aureus (AD strain) are selectively internalized into keratinocytes (HaCaT cells) compared to standard strains. However, the mechanism of AD strain internalization by keratinocytes and effect of the skin environment on internalization remain unclear. HaCaT cells were exposed to heat-killed AD or standard strains of fluorescently labeled S. aureus, with or without interferon (IFN)-γ, interleukin (IL)-4, and IL-13 cytokines, for 24 h. Filaggrin and fibronectin expression in HaCaT cells was knocked down using small interfering RNA. The amount of internalized S. aureus was evaluated using a cell imaging system. The effects of INF-γ, IL-4, and S. aureus exposure on mRNA expression in HaCaT cells were analyzed using single-cell RNA sequencing. AD strains adhered to HaCaT cells in approximately 15 min and were increasingly internalized for up to 3 h (2361 ± 467 spots/100 cells, mean ± SD), whereas the standard strain was not (991 ± 71 spots/100 cells). In the presence of IFN-γ, both the number of internalized strains and fibronectin expression significantly decreased compared to in the control, whereas Th2 cytokines had no significant effects. The number of internalized AD strains was significantly higher in filaggrin knockdown and lower in fibronectin knockdown HaCaT cells compared to in the control. RNA sequencing revealed that IFN-γ decreased both fibronectin and filaggrin expression. Keratinocyte internalization of the AD strain may be predominantly mediated by the INF-γ-fibronectin pathway and partially regulated by filaggrin expression.

A survey on subtypes and clinical characteristics of 1061 patients with urticaria in the primary care institutes in Japan.

The prevalence of urticaria has been reported mostly in Europe and North America. However, precise information regarding its subtypes and clinical characteristics in primary care practice, especially in Asian countries, are scant. Patients with urticaria and/or angioedema who visited nine primary clinics of accredited dermatologists and allergologists in Japan were recruited from October to November 2020. The information of age, sex, disease duration, urticaria control test (UCT), and concomitant urticaria subtypes were collected. A total of 1061 patients participated. The number of patients was high in the 20 to 50 age groups with a peak in the 40s. The most frequent urticaria subtype was chronic spontaneous urticaria (CSU) followed by dermographism, acute spontaneous urticaria (ASU), angioedema, and cholinergic urticaria (CholU) (66.8%, 22.7%, 18.9%, 14.1% and 5.7% in all patients with urticaria). CSU development increased with age from the 20s to 50s, especially in females. Dermographism had a peak in the 40s. ASU had bimodal peaks in childhood and in the 30s. CholU was common in males in the 10-20s. Most angioedema patients were female with an increase in their 30s. Angioedema was solely present in 14 of 1061 participants (1.3%), while 136 (12.8%) had angioedema concomitant with urticaria. UCT showed poorly controlled urticaria with lower scores in patients with concomitant CSU and other subtypes than in those with CSU alone. Urticaria tends to develop in young to middle-aged females. The most common urticaria subtype is CSU, while the number of patients with CholU is high and that of angioedema is low in Japan.

Immunological Changes of Basophil Hyperreactivity to Sweat in Patients With Well-Controlled Atopic Dermatitis.

Background: Sweat aggravates atopic dermatitis (AD). In patients with AD, type-I hypersensitivity to sweat may be shown by histamine release from patients' basophils in response to the semi-purified sweat antigen (QR), and the presence of specific immunoglobulin E (IgE) binding to MGL_1304, the component of QR. However, there has been no information on the immunological changes of type-I hypersensitivity to the sweat antigen in patients with well-controlled AD using topical corticosteroids (TCSs) and/or biologics as treatments. Method: Histamine-releasing tests using patients' basophils and QR and the detection of serum IgE against MGL_1304 and mite allergen Der f 1 were performed in patients with AD who were well controlled by topical TCS with/without dupilumab for 53-96 weeks. Results: In total, 14 patients were enrolled. Seven patients received TCS therapy alone (TCS group), and seven patients received TCS with dupilumab therapy (dupilumab group). In all participants, the level of specific IgE against MGL_1304 decreased after treatments, but histamine release from basophils in response to QR did not show a statistically significant reduction; rather, it increased. In the dupilumab group, all changes in histamine release induced by QR (increase), the IgE level against MGL_1304 (decrease), and that against Der f 1 (decrease) were statistically significant, whereas the TCS group showed no significant change in any of them. Conclusion: The well-controlled condition for 53-96 weeks resulted in no reduction of the hyperreactivity of basophils against in patients with AD, even with the treatment with dupilumab. This study suggests persistent basophil hyperreactivity to sweat antigen over a year or longer.

Real-world efficacy of proactive maintenance treatment with delgocitinib ointment twice weekly in adult patients with atopic dermatitis.

Previous studies have shown the efficacy of delgocitinib (DEL) ointment, a topical Janus kinase inhibitor, against atopic dermatitis (AD). However, there is no available information regarding the efficacy of DEL ointment in maintaining remission. Data of patients with AD who received remission maintenance therapy twice weekly with DEL or topical corticosteroid (TCS) on the affected skin of each upper limb were extracted from the medical records. Efficacy was assessed based on changes in pruritus numerical rating scale (NRS) score, stratum corneum hydration (SCH), erythema index (EI). Of 25 patients, four patients (16%) had eczema flare-ups on the TCS side and eight patients (32%) on the DEL side. The extent of change in each parameter between TCS- and DEL-treated areas of the skin did not differ significantly. The mean changes in the NRS and EI showed a slight improvement on the side treated with TCS and were slightly worse on the side treated with DEL. However, the SCH of the DEL group was maintained, while that of the TCS group worsened. TCS is more likely to be effective than DEL in terms of remission maintenance therapy. However, topical DEL is as effective as topical steroid in the maintenance therapy of AD in dry skin patients.

Clinical and histological characterization of transient dermal pain triggered by sweating stimuli.

BACKGROUND: Tingling dermal pain triggered by sweating impairs the lives of patients with cholinergic urticaria and generalized anhidrosis. However, dermal pain evoked by sweating stimuli has been under investigated. METHODS: To clarify characteristics of tingling dermal pain on sweating, we retrospectively evaluated clinical and histopathological manifestations in 30 patients having the main problem of dermal pain on sweating, and the efficacy of treatments. RESULTS: Dermal pain upon sweating affected mostly young males. It accompanied eruptions upon sweating and/or hypohidrosis in 24 patients, while 6 patients had dermal pain independently of hypohidrosis or eruptions. Dermal pain appeared immediately upon exposure to sweating stimuli, and disappeared within mostly 30 or 10 min. Hypohidrosis was not necessarily generalized but localized or absent. Histological analysis revealed that dermal pain could occur even without morphological changes and inflammation of sweat glands. Hypersensitivity to sweat contents was found only in 26% of patients. Sweat histamine and increase of plasma histamine after thermal induction in patients were significantly higher than those in healthy subjects. Effectiveness of steroid pulse therapy was demonstrated for dermal pain with hypohidrosis. Medications acting on nervous systems and regular sweat-inducing activities for promoting perspiration were also effective. CONCLUSIONS: Short-lasting tingling dermal pain appears immediately upon exposure to sweating stimuli, regardless of developing eruptions and/or presence of hypohidrosis, but possibly in association with sweat and plasma histamine.

Clinical course of more than 10 years in a patient with extensive skin burns who received cultured epidermal autograft transplantation.

Cultured epidermal autografts (CEAs) are used to treat extensive burns, giant congenital melanocytic nevi, and epidermolysis bullosa, but information about the long-term clinical course after CEA transplantation is scarce. Here we report 10 years' progress of a 7-year-old Japanese girl who suffered from a scald burn injury affecting 80% of her total body surface area and was treated with CEA transplantation. The skin of a child with extensive burns treated with CEAs appeared soft and of a good texture, even after 10 years, and recovery of skin pigmentation and scar condition were better at sites with a combination of CEAs and autologous skin grafts than those with CEAs alone.