Exploring the impact of ovariectomy on hair growth: can ovariectomized mouse serve as a model for investigating female pattern hair loss in humans?

Female pattern hair loss (FPHL), a type of hair disease common in pre- and postmenopausal women, is characterized by thinning of hair to O-type, mainly at the crown. Although a mouse model of this disease has recently been established, its details are still unknown, and thus, warrants further analysis. In this study, 3 week-old and 7- to 8 week-old C57BL/6 female mice were divided into two groups: one group underwent ovariectomy (OVX), while the other underwent sham surgery. In the 3 week-old mice, the dorsal skin was collected at seven weeks of age, while in the 7- to 8 week-old mice, it was collected at 12 and 24 weeks of age. In the former group, both the pore size of the hair follicles (HFs) and diameter of the hair shaft of telogen HFs decreased upon OVX; while in the latter group, these factors increased significantly. Notably, the thickness of the dermis and subcutis increased significantly in the OVX group. It needs to be further elucidated whether OVX mouse could serve as an ideal mouse model for FPHL, but our results upon evaluation of skin thickness indicate that it could be used to establish a novel treatment for non-hair-related diseases, such as post-menopause-related skin condition.

Human epithelial stem cell survival within their niche requires "tonic" cannabinoid receptor 1-signalling-Lessons from the hair follicle.

The endocannabinoid system (ECS) regulates multiple aspects of human epithelial physiology, including inhibition/stimulation of keratinocyte proliferation/apoptosis, respectively. Yet, how the ECS impacts on human adult epithelial stem cell (eSC) functions remains unknown. Scalp hair follicles (HFs) offer a clinically relevant, prototypic model system for studying this directly within the native human stem cell niche. Here, we show in organ-cultured human HFs that, unexpectedly, selective activation of cannabinoid receptor-1 (CB1)-mediated signalling via the MAPK (MEK/Erk 1/2) and Akt pathways significantly increases the number and proliferation of cytokeratin CK15+ or CK19+ human HF bulge eSCs in situ, and enhances CK15 promoter activity in situ. In striking contrast, CB1-stimulation promotes apoptosis in the differentiated progeny of these eSCs (CK6+ HF keratinocytes). Instead, intrafollicular CB1 gene knockdown or CB1 antagonist treatment significantly reduces human HF eSCs numbers and stimulates their apoptosis, while CB1 knockout mice exhibit a reduced bulge eSCs pool in vivo. This identifies "tonic" CB1 signalling as a required survival stimulus for adult human HF eSCs within their niche. This novel concept must be taken into account whenever the human ECS is targeted therapeutically.

Stress and Nasal Allergy: Corticotropin-Releasing Hormone Stimulates Mast Cell Degranulation and Proliferation in Human Nasal Mucosa.

Psychological stress exacerbates mast cell (MC)-dependent inflammation, including nasal allergy, but the underlying mechanisms are not thoroughly understood. Because the key stress-mediating neurohormone, corticotropin-releasing hormone (CRH), induces human skin MC degranulation, we hypothesized that CRH may be a key player in stress-aggravated nasal allergy. In the current study, we probed this hypothesis in human nasal mucosa MCs (hM-MCs) in situ using nasal polyp organ culture and tested whether CRH is required for murine M-MC activation by perceived stress in vivo. CRH stimulation significantly increased the number of hM-MCs, stimulated both their degranulation and proliferation ex vivo, and increased stem cell factor (SCF) expression in human nasal mucosa epithelium. CRH also sensitized hM-MCs to further CRH stimulation and promoted a pro-inflammatory hM-MC phenotype. The CRH-induced increase in hM-MCs was mitigated by co-administration of CRH receptor type 1 (CRH-R1)-specific antagonist antalarmin, CRH-R1 small interfering RNA (siRNA), or SCF-neutralizing antibody. In vivo, restraint stress significantly increased the number and degranulation of murine M-MCs compared with sham-stressed mice. This effect was mitigated by intranasal antalarmin. Our data suggest that CRH is a major activator of hM-MC in nasal mucosa, in part via promoting SCF production, and that CRH-R1 antagonists such as antalarmin are promising candidate therapeutics for nasal mucosa neuroinflammation induced by perceived stress.

Mutations in TSPEAR, Encoding a Regulator of Notch Signaling, Affect Tooth and Hair Follicle Morphogenesis.

Despite recent advances in our understanding of the pathogenesis of ectodermal dysplasias (EDs), the molecular basis of many of these disorders remains unknown. In the present study, we aimed at elucidating the genetic basis of a new form of ED featuring facial dysmorphism, scalp hypotrichosis and hypodontia. Using whole exome sequencing, we identified 2 frameshift and 2 missense mutations in TSPEAR segregating with the disease phenotype in 3 families. TSPEAR encodes the thrombospondin-type laminin G domain and EAR repeats (TSPEAR) protein, whose function is poorly understood. TSPEAR knock-down resulted in altered expression of genes known to be regulated by NOTCH and to be involved in murine hair and tooth development. Pathway analysis confirmed that down-regulation of TSPEAR in keratinocytes is likely to affect Notch signaling. Accordingly, using a luciferase-based reporter assay, we showed that TSPEAR knock-down is associated with decreased Notch signaling. In addition, NOTCH1 protein expression was reduced in patient scalp skin. Moreover, TSPEAR silencing in mouse hair follicle organ cultures was found to induce apoptosis in follicular epithelial cells, resulting in decreased hair bulb diameter. Collectively, these observations indicate that TSPEAR plays a critical, previously unrecognized role in human tooth and hair follicle morphogenesis through regulation of the Notch signaling pathway.

Multifaceted contribution of the TLR4-activated IRF5 transcription factor in systemic sclerosis.

Systemic sclerosis (SSc) is a multisystem autoimmune disorder with clinical manifestations resulting from tissue fibrosis and extensive vasculopathy. A potential disease susceptibility gene for SSc is IFN regulatory factor 5 (IRF5), whose SNP is associated with milder clinical manifestations; however, the underlying mechanisms of this association remain elusive. In this study we examined IRF5-deficient (Irf5(-/-)) mice in the bleomycin-treated SSc murine model. We show that dermal and pulmonary fibrosis induced by bleomycin is attenuated in Irf5(-/-) mice. Interestingly, we find that multiple SSc-associated events, such as fibroblast activation, inflammatory cell infiltration, endothelial-to-mesenchymal transition, vascular destabilization, Th2/Th17 skewed immune polarization, and B-cell activation, are suppressed in these mice. We further provide evidence that IRF5, activated by Toll-like receptor 4 (TLR4), binds to the promoters of various key genes involved in SSc disease pathology. These observations are congruent with the high level of expression of IRF5, TLR4, and potential endogenous TLR4 ligands in SSc skin lesions. Our study sheds light on the TLR4-IRF5 pathway in the pathology of SSc with clinical implications of targeting the IRF5 pathways in the suppression of disease development.

Unique mouse monoclonal antibodies reactive with maturation-related epitopes on type VII collagen.

In this study, we generated a new set of monoclonal antibodies (mAbs) to bovine and human type VII collagen (COL7) by immunizing mice with bovine cornea-derived basement membrane zone (BMZ) fraction. The four mAbs, tentatively named as COL7-like mAbs, showed speckled subepidermal staining in addition to linear BMZ staining of normal human skin and bovine cornea, a characteristic immunofluorescence feature of COL7, but showed no reactivity with COL7 by in vitro biochemical analyses. Taking advantage of the phenomenon that COL7-like mAbs did not react with mouse BMZ, we compared immunofluorescence reactivity between wild-type and COL7-rescued humanized mice and found that COL7-like mAbs reacted with BMZ of COL7-rescued humanized mice. In ELISAs, COL7-like mAbs reacted with intact triple-helical mammalian recombinant protein (RP) of COL7 but not with bacterial RP. Furthermore, COL7-like mAbs did not react with COL7 within either cultured DJM-1 cells or basal cells of skin of a bullous dermolysis of the newborn patient. These results confirmed that COL7-like mAbs reacted with human and bovine COL7. The epitopes for COL7-like mAbs were considered to be present only on mature COL7 after secretion from keratinocytes and deposition to BMZ and to be easily destroyed during immunoblotting procedure. Additional studies indicated association of the speckled subepidermal staining with both type IV collagen and elastin. These unique anti-COL7 mAbs should be useful in studies of both normal and diseased conditions, particularly dystrophic epidermolysis bullosa, which produces only immature COL7.

The discovery of epidermal tight junctions.

It was previously thought that the skin barrier is composed singly by the stratum corneum. However, this concept was overturned by the report of Tsukita's group in 2002. They convinced us that tight junctions exist in the stratum granulosum of the epidermis, with the constituent proteins being occludin, claudin-1 and claudin-4. However, more than 30 years before this, Hashimoto et al. described the possible existence of tight junctions in the epidermis in 'Intercellular spaces of the human epidermis as demonstrated with lanthanum' in 1971. Dr. Hashimoto observed lanthanum nitrate-injected human skin by electron microscopy. He discovered that the injected lanthanum penetrated the intercellular spaces of the basal and spinous layers of the epidermis and then moved towards the skin surface until penetration was halted in the granular cell layer near the stratum corneum. He described the cell-to-cell adhesion structures that blocked the movement of lanthanum as 'truly tight junctions'. Thus, this was the first description of the existence of tight junctions in the epidermis. However, the presence of these structures was denied by others and was forgotten. Thanks to the discovery of claudin, the existence of tight junctions between epidermal keratinocytes was finally confirmed. It is interesting that Hashimoto's finding was eventually proved to be correct three decades later as a result of progress in molecular biology. This article encourages us to recognize the importance of careful observation in the molecular biology era.

Cannabinoid receptor 1 controls human mucosal-type mast cell degranulation and maturation in situ.

BACKGROUND: Because many chronic inflammatory and allergic disorders are intimately linked to excessive mast cell (MC) numbers and activation, it is clinically important to understand the physiologic mechanisms preventing excess MC accumulation/degranulation in normal human tissues. OBJECTIVE: Because endocannabinoids are increasingly recognized as neuroendocrine regulators of MC biology, we investigated how cannabinoid receptor (CB) 1 signaling affects human mucosal-type mast cells (hMMCs). METHODS: Using organ-cultured nasal polyps as a surrogate tissue for human bronchial mucosa, we investigated how CB1 stimulation, inhibition, or knockdown affects hMMC biology using quantitative (immuno)histomorphometry and electron microscopy. RESULTS: Kit(+) hMMCs express functional CB1 in situ. Blockade of CB1 signaling (with the specific CB1 antagonist N-(piperidin-1-yl)-1-(2,4-dichlorophenyl)-5-(4-chlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide [AM251] or CB1 gene knockdown) enhanced hMMC degranulation and increased total numbers without affecting their proliferation in situ. This suggests that inhibiting CB1 signaling induces hMMC maturation from resident progenitor cells within human mucosal stroma. hMMC maturation was induced at least in part through upregulating stem cell factor production. Both the prototypic endocannabinoid anandamide and the CB1-selective agonist arachidonyl-2-chloroethylamide effectively counteracted secretagogue-triggered excessive hMMC degranulation. CONCLUSIONS: The current serum-free nasal polyp organ culture model allows physiologically and clinically relevant insights into the biology and pharmacologic responses of primary hMMCs in situ. In human airway mucosa hMMC activation and maturation are subject to a potent inhibitory endocannabinoid tone through CB1 stimulation. This invites one to target the endocannabinoid system in human airway mucosa as a novel strategy in the future management of allergic diseases.

Spatial and temporal control of laminin-332 and -511 expressions during hair morphogenesis.

Hair is one of the smallest organs, but has many important functions to mammals. Hair morphogenesis occurs through the reciprocal exchange of epithelial and mesenchymal signals. There are some reports about the expression of laminin-511 and -332 during hair morphogenesis, but are no reports of the chronological expression and function of laminin-511 and its counter regulator laminin-332 during hair morphogenesis. Our results of immunoblotting revealed that laminin-332 proteins were detected at stage 0 and downregulated during stage 1 to stage 2, and then recovered at stage 3. However, laminin α5 expression was constant throughout stages 0-3. According to the results of semi-quantitative RT-PCR, the mRNA expression of all laminin-332 subunits increased gradually from stage 0 to stage 2, while the mRNA expression of all laminin-511 subunits remained constant from stage 0 to stage 3. Our results suggest that the proper expression of laminin-332 and laminin-511 may regulate appropriate hair morphogenesis.

Cytoglobin functions as a redox regulator of melanogenesis in normal epidermal melanocytes.

Epidermal melanocytes are continuously exposed to sunlight-induced reactive oxygen species (ROS) and oxidative stress generated during the synthesis of melanin. Therefore, they have developed mechanisms that maintain normal redox homeostasis. Cytoglobin (CYGB), a ubiquitously expressed intracellular iron hexacoordinated globin, exhibits antioxidant activity and regulates the redox state of mammalian cells through its activities as peroxidase and nitric oxide (NO) dioxygenase. We postulated that CYGB functions in the melanogenic process as a regulator that maintains oxidative stress within a physiological level. This was examined by characterizing normal human melanocytes with the knockdown (KD) of CYGB using morphological and molecular biological criteria. CYGB-KD cells were larger, had more dendrites, and generated more melanin granules in the advanced stages of melanogenesis than control cells. The expression levels of major melanogenesis-associated genes and proteins were higher in CYGB-KD melanocytes than in wild type (WT) cells. As expected, CYGB-KD melanocytes generated more ROS and NO than WT cells. In conclusion, CYGB physiologically contributes to maintaining redox homeostasis in the melanogenic activity of normal melanocytes by controlling the intracellular levels of ROS and NO.

Endocannabinoids limit excessive mast cell maturation and activation in human skin.

BACKGROUND: Mast cells (MCs) crucially contribute to many inflammatory diseases. However, the physiological controls preventing excessive activities of MCs in human skin are incompletely understood. OBJECTIVE: Since endocannabinoids are important neuroendocrine MC modifiers, we investigated how stimulation/inhibition of cannabinoid 1 (CB1) receptors affect the biology of human skin MCs in situ. METHODS: This was investigated in the MC-rich connective tissue sheath of organ-cultured human scalp hair follicles by quantitative (immuno)histomorphometry, ultrastructural, and quantitative PCR techniques with the use of CB1 agonists or antagonists, CB1 knockdown, or CB1 knockout mice. RESULTS: Kit+ MCs within the connective tissue sheath of human hair follicles express functional CB1 receptors, whose pharmacological blockade or gene silencing significantly stimulated both the degranulation and the maturation of MCs from resident progenitor cells in situ (ie, enhanced the number of tryptase+, FcεRIα, or chymase+ connective tissue sheath-MCs). This was, at least in part, stem cell factor-dependent. CB1 agonists counteracted the MC-activating effects of classical MC secretagogues. Similar phenomena were observed in CB1 knockout mice, attesting to the in vivo relevance of this novel MC-inhibitory mechanism. CONCLUSION: By using human hair follicle organ culture as an unconventional, but clinically relevant model system for studying the biology of MCs in situ, we show that normal skin MCs are tightly controlled by the endocannabinoid system. This limits excessive activation and maturation of MCs from resident progenitors via "tonic" CB1 stimulation by locally synthesized endocannabinoids. The excessive numbers and activation of MCs in allergic and other chronic inflammatory skin diseases may partially arise from resident intracutaneous MC progenitors, for example, because of insufficient CB1 stimulation. Therefore, CB1 stimulation is a promising strategy for the future management of allergy and MC-dependent skin diseases.

Modulation of basophil activity: a novel function of the neuropeptide α-melanocyte-stimulating hormone.

BACKGROUND: Little is known about the effect of neuropeptides on basophils, which are important effector cells in immune and allergic responses. OBJECTIVE: This study aimed at revealing the role of α-melanocyte-stimulating hormone (α-MSH) on basophil function. METHODS: Expression of melanocortin receptors and proopiomelanocortin (POMC) was analyzed by means of RT-PCR, Western immunoblotting, fluorescence-activated cell sorting, and double-immunofluorescence analysis. Signal transduction studies included cyclic AMP and Ca(2+) mobilization assays. Basophil activity was assessed based on CD63 surface expression and cytokine release. RESULTS: MC-1R expression was detectable in basophils isolated from human peripheral blood, as well as in basophils within nasal tissue. In isolated basophils from human blood, truncated POMC transcripts were present, but there was no POMC protein. Treatment of basophils with α-MSH increased intracellular Ca(2+) but not cyclic AMP levels. α-MSH at physiologic doses potently suppressed basophil activation induced by N-formyl-methionyl-leucyl-phenylalanine, phorbol 12-myristate 13-acetate, or grass pollen allergen in whole blood of healthy or allergic subjects, respectively. The effect of α-MSH on basophil activation was MC-1R mediated (as shown by blockade with a peptide analogue of agouti-signaling protein) and imitated by adrenocorticotropic hormone but not elicited by the tripeptides KPV and KdPT, both of which lack the central pharmacophore of α-MSH. Moreover, α-MSH at physiologic doses significantly suppressed secretion of 3 proallergic cytokines, IL-4, IL-6, and IL-13, in basophils stimulated with anti-IgE, N-formyl-methionyl-leucyl-phenylalanine, or phorbol 12-myristate 13-acetate. CONCLUSION: Our findings highlight a novel functional activity of α-MSH, which acts as a natural antiallergic basophil-response modifier. These findings might point to novel therapeutic strategies in treating allergic diseases.

Prolactin--a novel neuroendocrine regulator of human keratin expression in situ.

The controls of human keratin expression in situ remain to be fully elucidated. Here, we have investigated the effects of the neurohormone prolactin (PRL) on keratin expression in a physiologically and clinically relevant test system: organ-cultured normal human hair follicles (HFs). Not only do HFs express a wide range of keratins, but they are also a source and target of PRL. Microarray analysis revealed that PRL differentially regulated a defined subset of keratins and keratin-associated proteins. Quantitative immunohistomorphometry and quantitative PCR confirmed that PRL up-regulated expression of keratins K5 and K14 and the epithelial stem cell-associated keratins K15 and K19 in organ-cultured HFs and/or isolated HF keratinocytes. PRL also up-regulated K15 promoter activity and K15 protein expression in situ, whereas it inhibited K6 and K31 expression. These regulatory effects were reversed by a pure competitive PRL receptor antagonist. Antagonist alone also modulated keratin expression, suggesting that "tonic stimulation" by endogenous PRL is required for normal expression levels of selected keratins. Therefore, our study identifies PRL as a major, clinically relevant, novel neuroendocrine regulator of both human keratin expression and human epithelial stem cell biology in situ.

A Case of Nevoid Acanthosis Nigricans Successfully Treated with Topical Ketoconazole Plus Urea.

Dear Editor, Nevoid acanthosis nigricans (AN) is a rare form of benign AN that can be mostly found as a solitary lesion distributed along Blaschko's lines (1). It is not associated with any known syndrome, endocrinopathy, drugs, or internal malignancy. Treatments include retinoid, calcipotriol, and laser treatments (2). Herein we report a case of nevoid AN successfully treated with topical ketoconazole plus urea. A 15-year-old woman presented with a 3-year history of asymptomatic plaques on her abdomen that were increasing in size. She had no medical history and no family history and was not obese. Physical examination revealed dark-brownish pigmented plaques on the midline and right side of her abdomen (Figure 1, a). Potassium hydroxide test was negative. Thyroid function test, antinuclear antibody test, and liver and renal function tests were within normal limits. Histological examination of skin biopsy showed hyperkeratosis and papillomatosis with minimal acanthosis and a mild perivascular lymphocytic infiltration in the superficial dermis (Figure 1, b). Some melanophages were observed in the superficial dermis. Based on the clinical features and these histological findings, a diagnosis of nevoid AN was established. Additionally, there were numerous hyphae and spores in the stratum corneum that were confirmed by Grocott staining (Figure 1, c) and periodic acid-Schiff staining (Figure 1, d). Fungal infection was suggested, and the result of a potassium hydroxide test was considered to be pseudo-negative. Topical ketoconazole cream was initially administrated for one month, and the rough surface was markedly improved (Figure 1, e). Subsequently, topical 20 % urea cream was used and the area of skin lesion decreased in size after 6 months (Figure 1, f). We discontinued ketoconazole cream after 2 months. To the best of our knowledge, this is the first case of nevoid AN successfully treated with topical ketoconazole plus urea. Some cases of AN appear to have an associated endocrinopathy (1). However, genetic factors may also play a role in the pathogenesis of AN. It has been reported that mosaic mutation in fibroblast growth factor 3 (FGFR3) is associated with nevoid AN (3). All known mutations in FGFR3 are gain-of-function mutations, and the activity of the FGFR3 signal correlates with the severity of AN. Involvement of fungal infection has not been reported in the pathogenesis of nevoid AN. We did not identify the fungal species in our patient, but Malassezia infection was suggested. In general, potassium hydroxide test can reveal only yeast forms of Malassezia, and pseudo-negative results may often occur. The abundant hyphae and spores in the stratum corneum are a characteristic pathological feature of Malassezia infection, and the obvious effects of ketoconazole may support the Malassezia infection. Since Malassezia is known to promote cytokine production in human keratinocytes (4), an autocrine FGFR3 signal might accelerate the proliferation of keratinocytes such as myeloma cells (5). Urea is the most widely used moisturizer and keratolytic agent, and has been utilized for the treatment of various hyperkeratotic cutaneous diseases. We successfully treated nevoid AN with the combination of topical ketoconazole and urea. This combination therapy may have fewer side-effects than previous reported treatments and could be considered as an optional treatment. Acknowledgment: The patients in this manuscript have given written informed consent to publication of their case details.

Methods in hair research: how to objectively distinguish between anagen and catagen in human hair follicle organ culture.

The organ culture of human scalp hair follicles (HFs) is the best currently available assay for hair research in the human system. In order to determine the hair growth-modulatory effects of agents in this assay, one critical read-out parameter is the assessment of whether the test agent has prolonged anagen duration or induced catagen in vitro. However, objective criteria to distinguish between anagen VI HFs and early catagen in human HF organ culture, two hair cycle stages with a deceptively similar morphology, remain to be established. Here, we develop, document and test an objective classification system that allows to distinguish between anagen VI and early catagen in organ-cultured human HFs, using both qualitative and quantitative parameters that can be generated by light microscopy or immunofluorescence. Seven qualitative classification criteria are defined that are based on assessing the morphology of the hair matrix, the dermal papilla and the distribution of pigmentary markers (melanin, gp100). These are complemented by ten quantitative parameters. We have tested this classification system by employing the clinically used topical hair growth inhibitor, eflornithine, and show that eflornithine indeed produces the expected premature catagen induction, as identified by the novel classification criteria reported here. Therefore, this classification system offers a standardized, objective and reproducible new experimental method to reliably distinguish between human anagen VI and early catagen HFs in organ culture.

[Ratio of serum levels of 1,25-dihydroxyvitamin D3 and parathyroid hormone for the diagnosis and treatment of tuberculous peritonitis in a chronic kidney disease patient: a case report].

An 80-year-old man was admitted to our hospital because of exacerbation of preexisting chronic kidney disease (CKD). On admission, he showed elevated levels of serum creatinine (6.37 mg/dL) and corrected calcium (13.7 mg/dL). Although the serum levels of intact parathyroid hormone (I-PTH) and parathyroid hormone-related peptide(PTITH-rP)were low, the serum 1,25-dihydroxyvitamin D3 (1,25 (OH)2D3)levels were high. Computed tomography (CT) revealed ascites, and the ascitic fluid was exudative and serous with predominance of lymphocytes. The levels of adenosine deaminase (ADA) in the ascitic fluid were also elevated, and the results of QuantiFERON-TB2G (QFT-2G)assay were positive, indicating tuberculous peritonitits. Ascites resolved rapidly after initiation of the antituberculosis therapy. The elevated levels of serum calcium and 1,25 (OH) 2D3 returned to below-normal levels; however, serum i-PTH levels increased from 8.9 pg/ mL to 432 pg/mL. Diagnosis of extrapulmonary tuberculosis is often difficult in CKD patients. CKD patients show abnormal vitamin D activation, so these patients usually have low levels of serum 1,25(OH)2D3. On the other hand, in our patient, 1,25(OH)2D3 was extrarenally produced from tuberculous granuloma and therefore, he showed high levels of serum 1,25(OH)2D3 and correspondingly, low levels of serum i-PTH. We observed that the ratio of 1,25 (OH) 2D3:i-PTH decreased due to antituberculosis therapy. This ratio facilitated the diagnosis and evaluation of treatment for this condition.

A Case of Dapsone-induced Mild Methemoglobinemia with Dyspnea and Cyanosis.

Dear Editor, Dapsone is a dual-function drug with antimicrobial and antiprotozoal effects and anti-inflammatory features (1). In dermatology, it is a first choice for conditions such as leprosy, IgA pemphigus, dermatitis herpetiformis, and linear IgA bullous dermatosis, or an adjunctive treatment for, e.g. bullous pemphigoid (BP) and pemphigus vulgaris (1). However, dapsone is associated with some adverse effects, including methemoglobinemia (1). Methemoglobin (MetHb) concentrations of less than 15% usually cause no symptoms in patients with normal hemoglobin concentrations (2). Herein, we report the case of a patient with BP who developed dyspnea because of dapsone-induced methemoglobinemia that was as mild as 4.7%. A 93-year-old man was diagnosed with BP based on skin manifestations (Figure 1, a and b), histopathological findings (Figure 1, c and d), and anti-BP180 NC16A antibody titer determined by chemiluminescence enzyme immunoassay (279 U/mL) 3 years earlier. His comorbidities included diabetes mellitus, chronic heart failure, right pleural effusion, and brain infarction. The patient had been successfully treated with oral prednisolone, so the steroid was tapered to 4 mg/day. The blisters recurred, however, and new ones kept developing even though the prednisolone was increased to 25 mg/day. Dapsone (75 mg/day) was begun as adjunctive treatment, and new blister formation ceased. At one week from dapsone initiation, the patient developed dyspnea, and his oxygen saturation as measured by pulse oximetry decreased to 88% on room air. At presentation, his blood pressure was 118/78 mmHg, the heart rate was 95 beats/minute, and axillary temperature was 36.3 °C. Neurological examination and consciousness findings remained unchanged compared with findings before dyspnea onset. Chest examination showed normal breath and heart sounds, but lip and peripheral cyanosis was present. Blood tests revealed a white blood cell count of 12,920/µl; red blood cells, 370×104/µl; hemoglobin, 11.7 g/dl; and CMV antigenemia (or C7-HRP), negative. Chest CT and echocardiography indicated no remarkable change compared with imaging from one year earlier. Arterial blood gas analysis showed a pH of 7.454, PaO2 63.1 mmHg, PaCO2 35.4 mmHg, HCO3- 24.3 mmol/L, SaO2 92.4%, and MetHb of 4.7%. These findings indicated a saturation gap (difference between SpO2 and SaO2) induced by MetHb. Upon cessation of dapsone, MetHb levels and SpO2 returned to normal and the dyspnea resolved, implicating dapsone in the methemoglobinemia (Figure 1, e). Differential diagnoses were pulmonary disease, heart disease, neuromuscular disease, sepsis, and drug intoxication. These possibilities were ruled out by the physical examination, drug history, vital signs, blood tests, and chest CT and echocardiography. In normal individuals, MetHb levels are less than 1% (2). Healthy patients with normal hemoglobin concentrations develop cyanosis at MetHb level of 15-20%, dyspnea at 20-50%, and coma at 50-70%, and die at more than 70% (2). However, patients with hematologic disease, acidosis, or cardiopulmonary diseases, for example, present with symptoms even with MetHb levels less than 15% (2,3). We inferred that our patient presented with dyspnea even under mild methemoglobinemia because he had anemia, chronic heart failure, and right pleural effusion. The occurrence of dapsone-induced methemoglobinemia with obvious symptoms is rare (1,4). Clinicians should be aware that methemoglobinemia symptoms are influenced not only by MetHb concentrations but also by comorbidities.

The Mast Cell-SCF-CB1 Interaction Is a Key Player in Seborrheic Keratosis.

Mast cell (MC) is an important player in the development of skin diseases, including atopic dermatitis, psoriasis, and urticaria. It is reported that MC infiltration and activation are observed around various types of tumors and speculated that MCs play key roles in their pathogenesis. As MCs in human seborrheic keratosis (SK) have not been well investigated, here we focused on the MCs in SK. The number of c-Kit and tryptase-positive MCs was significantly increased around the SK compared with the marginal lesion. Degranulated MCs were also increased around the tumors. Furthermore, MC growth factor, stem cell factor (SCF), expression within the SK was significantly upregulated compared with the marginal lesion. Interestingly, one of the cognitive regulators of SCF expression, cannabinoid receptor type 1 (CB1) immunoreactivity was downregulated within the SK. Our results suggest that MCs play important roles in the pathogenesis of SK and that SCF can be also deeply involved in the development of SKs. Our current results highlight the CB1-SCF-MC interaction as a novel mechanism of SK development and this also will be utilized for developing a novel treatment.

Homeostatic Function of Dermokine in the Skin Barrier and Inflammation.

Dermokine is a chiefly skin-specific secreted glycoprotein localized in the upper epidermis, and its family consists of three splice variants in mice and five in humans. To investigate the pathophysiological impact of dermokine, we generated mice deficient for two (ßγ) or all dermokine isoforms (αßγ). Both variants, especially dermokine αßγ-deficient mice exhibited scale and wrinkle formation resembling ichthyosis accompanied by transepidermal water imbalance at the neonatal stage. Several dermokine αßγ-deficient mice died by postnatal day 21 when reared under low humidity. Moreover, the cornified envelope was vulnerable, and skin barrier lipid ceramides were reduced in the epidermis of dermokine αßγ-deficient mice. cDNA microarray and quantitative reverse transcriptase-PCR assays of the epidermis revealed the upregulation of small proline-rich protein and late cornified envelope family members, as well as antimicrobial peptides in the dermokine αßγ-deficient mice. These barrier gene signatures were similar to that seen in psoriasis, whereas recent studies demonstrated that congenital ichthyosis has gene profiles resembling psoriasis. In line with these findings, adult dermokine αßγ-deficient mice exhibited aggravated phenotypes in psoriasis-like dermatitis models but not in allergic dermatitis models. Dermokine may play a regulatory role in inflammatory dyskeratotic diseases, such as congenital ichthyosis and psoriasis, in the crosstalk between barrier dysfunction and inflammation.