Saki Matsui

Periostin Facilitates Skin Sclerosis via PI3K/Akt Dependent Mechanism in a Mouse Model of Scleroderma

Objective Periostin, a novel matricellular protein, is recently reported to play a crucial role in tissue remodeling and is highly expressed under fibrotic conditions. This study was undertaken to assess the role of periostin in scleroderma. Methods Using skin from patients and healthy donors, the expression of periostin was assessed by immunohistochemistry and immunoblotting analyses. Furthermore, we investigated periostin−/− (PN−/−) and wild-type (WT) mice to elucidate the role of periostin in scleroderma. To induce murine cutaneous sclerosis, mice were subcutaneously injected with bleomycin, while untreated control groups were injected with phosphate-buffered saline. Bleomycin-induced fibrotic changes were compared in PN−/− and WT mice by histological analysis as well as by measurements of profibrotic cytokine and extracellular matrix protein expression levels in vivo and in vitro. To determine the downstream pathway involved in periostin signaling, receptor neutralizing antibody and signal transduction inhibitors were used in vitro. Results Elevated expression of periostin was observed in the lesional skin of patients with scleroderma compared with healthy donors. Although WT mice showed marked cutaneous sclerosis with increased expression of periostin and increased numbers of myofibroblasts after bleomycin treatment, PN−/− mice showed resistance to these changes. In vitro, dermal fibroblasts from PN−/− mice showed reduced transcript expression of alpha smooth actin and procollagen type-I alpha 1 (Col1α1) induced by transforming growth factor beta 1 (TGFβ1). Furthermore, recombinant mouse periostin directly induced Col1α1 expression in vitro, and this effect was inhibited by blocking the αv integrin-mediated PI3K/Akt signaling either with anti-αv functional blocking antibody or with the PI3K/Akt kinase inhibitor LY294002. Conclusion Periostin plays an essential role in the pathogenesis of Bleomycin-induced scleroderma in mice. Periostin may represent a potential therapeutic target for human scleroderma.

Sweat, the driving force behind normal skin: An emerging perspective on functional biology and regulatory mechanisms

The various symptoms associated with excessive or insufficient perspiration can significantly reduce a patients quality of life. If a versatile and minimally invasive method could be established for returning sweat activity to normalcy, there is no question that it could be used in the treatment of many diseases that are believed to involve perspiration. For this reason, based on an understanding of the sweat-gland control function and sweat activity, it was necessary to conduct a comprehensive search for the factors that control sweating, such as the central and peripheral nerves that control sweat-gland function, the microenvironment surrounding the sweat glands, and lifestyle. We focused on the mechanism by which atopic dermatitis leads to hypohidrosis and confirmed that histamine inhibits acetylcholinergic sweating. Acetylcholine promotes the phosphorylation of glycogen synthesis kinase 3β (GSK3β) in the sweat-gland secretory cells and leads to sensible perspiration. By suppressing the phosphorylation of GSK3β, histamine inhibits the movement of sweat from the sweat-gland secretory cells through the sweat ducts, which could presumably be demonstrated by dynamic observations of the sweat glands using two-photon microscopy. It is expected that the discovery of new factors that control sweat-gland function can contribute to the treatment of diseases associated with dyshidrosis.

Dynamic analysis of histamine-mediated attenuation of acetylcholine-induced sweating via GSK3β activation

Sweating has been associated with the exacerbation of atopic dermatitis (AD) in diverse ways. Acetylcholine (ACh)-mediated sweating is known to be attenuated in AD, but its cause remains obscure. To address this issue, the impact of histamine on ACh-induced sweating was evaluated. Sweating was measured by counting the number of active sweat pores by the starch-iodine reaction and dynamic optical coherence tomography; sweat was visualized using two-photon excitation fluorescence microscopy in mice and the quantitative sudomotor axon reflex test in humans. Both histamine receptor antagonists and H1 receptor (H1R)-knockout (KO) mice were used to determine methodological specificity. Histamine demonstrably inhibited ACh-induced sweating in both mice and humans via H1R-mediated signaling. In sweat glands, ACh inactivated glycogen synthase kinase 3β (GSK3β), a kinase involved in endocytosis and secretion, whereas simultaneous stimulation with histamine activated GSK3β. Results of two-photon excitation fluorescence microscopy confirmed the dynamic motion of sweat and sweat glands after ACh treatment, showing that simultaneous stimulation with histamine altered their dynamic properties. These results indicate that histamine inhibits sweat gland secretions by blocking ACh-induced inactivation of GSK3β. Histamine-mediated hypohidrosis might be involved in the mechanism of abnormal skin dryness in patients with AD.

Abnormal axon reflex-mediated sweating correlates with high state of anxiety in Atopic Dermatitis

BACKGROUND Sweating plays a key role in skin homeostasis, including antimicrobial and moisturizing effects, and regulation of skin surface pH. Impaired axon reflex-mediated (AXR) sweating has been observed in patients with atopic dermatitis (AD). However, the mechanism of such abnormal sudomotor axon reflex remains to be revealed. METHODS To investigate this mechanism, sudomotor function was analyzed using a quantitative sudomotor axon reflex test (acetylcholine iontophoresis) in patients with AD (n = 26) and healthy volunteers (n = 12). Correlation between sudomotor function and certain background factors, including Spielberger State Trait Anxiety Inventory score, Severity Scoring of Atopic Dermatitis (SCORAD) score, number of circulating eosinophils, and serum concentrations of thymus and activation-regulated chemokine and immunoglobulin E radioimmunosorbent test, was validated. RESULTS Latency time was significantly prolonged in AD (p = 0.0352), and AXR sweating volume (mg/0-5 min) was significantly lower in AD patients than in healthy controls (p = 0.0441). Direct sweating volume (mg/0-5 min) was comparable in AD patients and healthy controls. A significant correlation between the evaluation results of quantitative sudomotor axon reflex tests and certain background factors was not observed. The latency time in non-lesioned and lesioned areas for AD patients versus continuous anxiety value in the Spielberger State Trait Anxiety Inventory and the AXR versus SCORAD showed significant correlations (p = 0.0424, p = 0.0169, and p = 0.0523, respectively). CONCLUSIONS Although the number of study subjects was little, abnormal AXR sweating in patients with AD was observed. Correlative analysis suggests possible involvement of continuous anxiety and the immune system in such abnormal sudomotor function.

Four Cases of Atopic Dermatitis Complicated by Sjögren's Syndrome: Link between Dry Skin and Autoimmune Anhidrosis

We report four adult cases of atopic dermatitis (AD) complicated by Sjögrens syndrome (SS). The patients fulfilled diagnostic criteria for AD and SS. All cases showed persistent itchy dry skin and eczematous lesions complicated by sicca symptoms including dry eyes and dry mouth with moderate joint pain. One case manifested annular erythema and another manifested widespread discoid erythema. To investigate the underlying cause of dry skin in these cases, sweating function was evaluated using a quantitative sudomotor axon reflex test (QSART) in which the axon reflex is stimulated by acetylcholine iontophoresis. The sweating latency time was significantly prolonged in eczematous skin of AD and AD/SS compared to normal controls. Axon reflex (AXR) sweat volume was also significantly reduced in AD (normal and eczematous skin) and AD/SS (normal and eczema) compared to normal control. In contrast, the direct sweat volume of lesional or non-lesional AD skin induced by direct stimulation with acetylcholine was only slightly reduced compared to that in normal controls, but not in SS and lesional skin of AD/SS patients. These results suggest that the impaired sweat response in AD is attributable to an abnormal sudomotor axon reflex, which is accelerated and modulated when complicated by SS resulting in dry skin in the present cases.We report four adult cases of atopic dermatitis (AD) complicated by Sjogrens syndrome (SS). The patients fulfilled diagnostic criteria for AD and SS. All cases showed persistent itchy dry skin and eczematous lesions complicated by sicca symptoms including dry eyes and dry mouth with moderate joint pain. One case manifested annular erythema and another manifested widespread discoid erythema. To investigate the underlying cause of dry skin in these cases, sweating function was evaluated using a quantitative sudomotor axon reflex test (QSART) in which the axon reflex is stimulated by acetylcholine iontophoresis. The sweating latency time was significantly prolonged in eczematous skin of AD and AD/SS compared to normal controls. Axon reflex (AXR) sweat volume was also significantly reduced in AD (normal and eczematous skin) and AD/SS (normal and eczema) compared to normal control. In contrast, the direct sweat volume of lesional or non-lesional AD skin induced by direct stimulation with acetylcholine was only slightly reduced compared to that in normal controls, but not in SS and lesional skin of AD/SS patients. These results suggest that the impaired sweat response in AD is attributable to an abnormal sudomotor axon reflex, which is accelerated and modulated when complicated by SS resulting in dry skin in the present cases.

Decreased Sudomotor Function is Involved in the Formation of Atopic Eczema in the Cubital Fossa

BACKGROUND Eczema in the cubital fossa, which is susceptible to sweat, is frequently observed in atopic dermatitis (AD). However, there has been no direct evidence that sweating causes eczema in the cubital fossa. METHODS To investigate this issue, axon reflex-mediated sweating volume (AXR) and skin barrier function in the cubital fossa were measured in subjects with AD and in healthy volunteers, and were applied to clinical feature of the cubital fossa. RESULTS AXR in the cubital fossa decreased in AD subjects; it positively correlated only with water-holding capacity in healthy subjects but not in patients with in AD. Furthermore, AD subjects with lichenoid eczema and either prurigo or papules over the cubital fossa showed extremely decreased AXR. CONCLUSIONS These results suggest that decreased sweating is a major source of water in the stratum corneum, and decreased sudomotor function may be involved in both the cause and aggravation of representative atopic eczema in the cubital fossa.

Idiopathic pure sudomotor failure responding to oral antihistamine with sweating activities.

© 2014 The Authors. doi: 10.2340/00015555-1820 Journal Compilation

Increased frequency of skin-infiltrating FoxP3+ regulatory T cells as a diagnostic indicator of severe atopic dermatitis from cutaneous T cell lymphoma

Differential diagnosis of cutaneous T cell lymphoma (CTCL) and severe atopic dermatitis (AD) is often difficult because of the similarity in their skin manifestations. However, such differentiation is extremely important because of the differences in remedy and prognosis. The aim of this study was to investigate new, helpful diagnostic aids for distinguishing CTCL from AD. The frequency of forkhead box protein 3+ (FoxP3+) regulatory T cells (Tregs) in cutaneous lesions was evaluated among the three populations. Serum‐soluble interleukin‐2 receptor (sIL‐2R), immunoglobulin (Ig)E‐radioimmunosorbent test, lactate dehydrogenase (LDH) and blood eosinophil count were measured in 11 CTCL patients (including three CTCL patients misdiagnosed previously with intractable AD), 10 adult AD patients and nine psoriasis patients. The frequency of Tregs was increased significantly in cutaneous lesions of AD compared with those of CTCL. Serum IgE and LDH levels were also elevated significantly in AD compared with CTCL, whereas there were no significant differences in serum sIL‐2R levels between CTCL and AD. In the three CTCL patients who were misdiagnosed with intractable AD, IgE and LDH levels were lower than in AD patients, whereas serum sIL‐2R levels were as high as in AD patients and higher than in the other eight CTCL patients. The higher frequency of Tregs in the cutaneous lesions of patients with AD than in those with CTCL and higher serum IgE and LDH levels in patients with AD than in those with CTCL might be helpful reference values for the differential diagnosis of these two diseases.

A case of disseminated DLE complicated by atopic dermatitis and Sjögren’s syndrome: link between hypohidrosis and skin manifestations

We report an unusual case of disseminated discoid lupus erythematosus (DLE) complicated by pre-existing atopic dermatitis (AD) and late-onset Sjögren’s syndrome (SS). Disseminated DLE lesions were sparse on the expected sites for AD, such as the medial region of the extremities or v-neck area. The patient fulfilled the diagnostic criteria for AD and SS but not for systemic lupus erythematosus. Histopathological analysis of the crusted erythematous lesions revealed typical DLE with few FoxP3+ cells and a moderate number of IL-17+ cells. A quantitative sweating test showed impaired sweating of both lesional and non-lesional skin due to underlying hypohidrosis that was related to AD and SS. This finding suggests that dissemination of DLE was triggered by scratching and a Köbner phenomenon-like effect related to hypohidrotic and xerotic skin. To the best of our knowledge, this is the first reported case of disseminated DLE complicated by AD and SS.

Topical cholesterol treatment ameliorates hapten-evoked cutaneous hypersensitivity by sustaining expression of 11β-HSD1 in epidermis.

Changes in the stratum corneum extracellular matrix impair epidermal barrier function and may cause dermatoses. The aim of this study was to examine the effect of exogenous cholesterol application on skin barrier function and cutaneous inflammation. Skin barrier‐disrupted or hapten‐stimulated mice were treated with topical cholesterol. The effect of topical cholesterol application on an oxazolone (OXA)‐induced hypersensitivity reaction was evaluated. Topical application of cholesterol efficiently decreased transepidermal water loss in areas of barrier‐disrupted skin and ameliorated OXA‐induced cutaneous hypersensitivity. These favourable effects may have resulted from sustained expression of 11β‐hydroxysteroid dehydrogenase type 1 (11β‐HSD1) in the cholesterol‐treated skin. As 11β‐HSD1 is known to produce active cortisol, topical cholesterol may attenuate contact hypersensitivity by normalizing secretion of hormonally active cortisol from the skin.