A retrospective clinicopathological study of erythema nodosum.

Erythema nodosum (EN) may be idiopathic or secondary, and usually resolves naturally within 1-2 months. In atypical EN cases, the rash extends beyond the lower limbs to the upper limbs and trunk, and histopathological findings may be accompanied by vasculitis in addition to septal panniculitis. Few studies have examined the differences in the clinical characteristics of patients with EN based on rash distribution. We retrospectively examined whether there was a correlation with clinical information, such as the presence or absence of underlying diseases, by classifying the patients into two groups: the lower limbs group (the EN rash was confined to the lower limbs) and the beyond lower limbs group (the EN rash appeared beyond the lower limbs). Among the 86 adult patients diagnosed with EN at the Dermatology Department of Fujita Medical University between 2015 and 2020, there were 65 cases of the lower limbs group and 21 cases of the beyond lower limbs group. The frequency of underlying diseases was significantly higher in the beyond lower limbs group (76.2%, 16 cases) than in the lower limbs group (40.0%, 26 cases; P < 0.005). Vasculitis was more notable in the beyond lower limbs group (P < 0.05). Significantly higher vasculitis was noted in the EN group with underlying diseases (30.2%, 13 cases) than in the idiopathic EN group without underlying diseases (11.6%, 5 cases; P < 0.05). Neutrophil extracellular traps were positive in approximately 40% of cases in both groups. In the beyond lower limbs group, the possibility of severe cases with underlying diseases, vasculitis, and inflammation must be considered for effective treatment.

A clinicopathological analysis of forkhead box A1 (FOXA1) and estrogen receptor alpha expression in extramammary Paget's disease.

Objectives: Extramammary Paget's disease (EMPD) is a neoplastic skin disease of unknown etiology. EMPD is frequently associated with forkhead box A1 (FOXA1) expression, which correlates with the expression of estrogen receptor alpha (ER). FOXA1 regulates the transcriptional activity of ER and may function cooperatively in the tumorigenesis of breast cancer. Methods: We performed immunohistochemical staining for FOXA1 and ER using tissue samples from 16 patients with EMPD. Results: The nuclei of Paget cells isolated from each of the 16 patients with EMPD (100%) were strongly FOXA1-positive, and the FOXA1 staining intensity was similar across all samples. ER staining was detected in the nuclei of Paget cells originating from seven patients with EMPD (44%), and the ER staining intensity varied between these patients. Conclusions: In the present study, we confirmed that EMPD was frequently associated with FOXA1 expression. However, ER expression varied between patients and did not always coincide with FOXA1 expression. No clear relationship was observed between ER expression, the intensity of ER staining, or EMPD metastasis and prognosis. However, the results indicate that hormone-dependent cancer therapy may be effective in patients with ER-positive EMPD.

Syphilis With Multiple Pulmonary Nodules and Bone Lesions Detected on Computed Tomography and 18F Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

Syphilis can cause a wide range of systemic manifestations, such as papular rash, malaise, weight loss, muscle aches, generalized lymphadenopathy, and meningitis. However, pulmonary involvement in patients with secondary syphilis is thought to be relatively rare. Moreover, bone involvement in patients with secondary syphilis is also considered rare, and only a few cases of involvement of lung and bone in such patients have been reported. In this paper, we report a case of secondary syphilis with pulmonary involvement in the form of multiple nodules with low attenuation areas, lymphadenopathy and multiple bone lesions detected on computed tomography and 18F fluorodeoxyglucose-positron emission tomography/computed tomography.

Melanin accumulation in dermal stem cells deteriorates their exosome-mediated skin basement membrane construction in solar lentigo.

Solar lentigo (SL) is a hyperpigmented macule that occurs in sun-exposed areas and is characterized by the accumulation of melanin pigment in the epidermis. On the contrary, melanin-incorporated macrophages have also been identified in the dermis, which is thought to be caused by melanin transfer due to disruption of the basement membrane, but the detailed mechanism remains unclear. In this study, we analysed SL lesions by pathological methods and examined the mechanism of melanin accumulation in the dermis using cultured skin models in vitro. First, we observed a significant decrease in type IV collagen (COL4), a major component of the basement membrane, in SL lesions. The basement membrane is known to be formed by the interaction of keratinocytes and dermal cells. Therefore, we constructed skin models containing fibroblasts or dermal stem cells and examined their effects on basement membrane formation. The results showed a markedly enhanced production of COL4 mediated by dermal stem cell-derived exosomes. The analysis of melanin localization in the SL dermis revealed that CD163-positive macrophages and CD271-positive dermal stem cells both took up melanin pigment. Exosomes of dermal stem cells incorporating melanosomes were less effective in promoting COL4 expression. These findings suggest that while the promotion of COL4 production in keratinocytes by dermal stem cell-derived exosomes is important for maintaining basement membrane homeostasis, this mechanism is disrupted in SL lesions, leading to chronic melanin accumulation in the dermis.

Neutrophil extracellular traps are involved in enhanced contact hypersensitivity response in IL-36 receptor antagonist-deficient mice.

Loss-of-function homozygous or compound heterozygous mutations in IL36RN, which encodes interleukin-36 receptor antagonist (IL-36Ra), have been implicated in the pathogenesis of skin disorders. We previously reported that Il36rn-/- mice exhibit an enhanced contact hypersensitivity (CHS) response through increased neutrophil recruitment. In addition, Il36rn-/- mice show severe imiquimod-induced psoriatic skin lesions and enhanced neutrophil extracellular trap (NET) formation. We hypothesized that NETs may play an important role in the CHS response. To confirm this, we examined the CHS response and NET formation in Il36rn-/- mice. Il36rn-/- mice showed enhanced CHS responses, increased infiltration of inflammatory cells, including neutrophils, CD4+ T cells, and CD8+ T cells, NET formation, and enhanced mRNA expression of cytokines and chemokines, including IL-1ß, C-X-C motif chemokine ligand (CXCL)1, CXCL2, and IL-36γ. Furthermore, NET formation blockade improved the CHS response, which consequently decreased inflammatory cell infiltration and NET formation. Consistently, we observed decreased expression of these cytokines and chemokines. These findings indicate that IL-36Ra deficiency aggravates the CHS response caused by excessive inflammatory cell recruitment, NET formation, and cytokine and chemokine production, and that NET formation blockade alleviates the CHS response. Thus, NET formation may play a prominent role in the CHS response.

Enhanced Type I Collagen Synthesis in Fibroblasts by Dermal Stem/Progenitor Cell-Derived Exosomes.

The self-duplication and differentiation of dermal stem cells are essential for the maintenance of dermal homeostasis. Fibroblasts are derived from dermal stem cells and produce components of connective tissue, such as collagen, which maintains the structure of the dermis. Cell-cell communication is required for the maintenance of tissue homeostasis, and the role of exosomes in this process has recently been attracting increasing attention. Dermal stem cells and fibroblasts have been suggested to communicate with each other in the dermis; however, the underlying mechanisms remain unclear. In the present study, we investigated communication between dermal stem/progenitor cells (DSPCs) and fibroblasts via exosomes. We collected exosomes from DSPCs and added them to a culture of fibroblasts. With the exosomes, COL1A1 mRNA expression was up-regulated and dependent on the Akt phosphorylation. Exosomes collected from fibroblasts did not show the significant up-regulation of COL1A1 mRNA expression. We then performed a proteomic analysis and detected 74 proteins specific to DSPC-derived exosomes, including ANP32B related to Akt phosphorylation. We added exosomes in which ANP32B was knocked down to a fibroblast culture and observed neither Akt phosphorylation nor enhanced type I collagen synthesis. Additionally, an immunohistochemical analysis of skin tissues revealed that ANP32B expression levels in CD271-positive dermal stem cells were lower in old subjects than in young subjects. These results suggest that DSPCs promote type I collagen synthesis in fibroblasts by secreting exosomes containing ANP32B, which may contribute to the maintenance of skin homeostasis; however, this function of DSPCs may decrease with aging.

Increase in inhibin beta A/Activin-A expression in the human epidermis and the suppression of epidermal stem/progenitor cell proliferation with aging.

BACKGROUND: Age-related thinning and reduced cell proliferation in the human epidermis are associated with the accumulation of senescent cells and decreases in the number and function of epidermal stem cells. OBJECTIVE: This study examined the expression of INHBA/Activin-A in human epidermis and expression differences with age, and the effect of Activin-A on epidermal stem/progenitor cells. METHODS: Immunohistochemical staining was used to analyze age-related changes in the expression of INHBA/Activin-A in the epidermal tissue of young and old subjects. Epidermal INHBA/Activin-A expression levels, epidermal morphology, and the number of epidermal stem/progenitor cells or proliferating cells were investigated using older abdominal skin samples. The effects of Activin-A on the development of a three-dimensional (3D) reconstructed epidermis and cell proliferation were also assessed. RESULTS: INHBA/Activin-A expression levels in the human epidermis increased with age, although they varied among individuals. In the epidermis of older abdominal skin samples, INHBA/Activin-A expression levels negatively correlated with epidermal thickness, the rete ridge depth and the interdigitation index. The proportion of epidermal stem/progenitor cells and proliferating cells decreased with increases in INHBA/Activin-A expression levels. Activin-A had no effect on the differentiation of keratinocytes in the 3D-reconstructed epidermis; however, thinning of the 3D epidermis was noted. Moreover, the addition of Activin-A inhibited the proliferation of epidermal stem/progenitor cells in a concentration-dependent manner. CONCLUSIONS: Age-related increased in INHBA/Activin-A expression levels were observed in the human epidermis, and may contribute to epidermal thinning and decreases in the number of epidermal stem/progenitor cells and proliferative activity.

Age-related decrease in responsiveness of CD271-positive skin stem cells to growth factors.

Previous studies have demonstrated that the numbers of interfollicular epidermal stem cells (IFE-SCs) and dermal stem cells (DSCs) decrease with age and that this decrease is attributed to the age-related deterioration of skin homeostatic functions and the delay in wound healing. Meanwhile, functional decline in the stem cells is also considered to be responsible for the deteriorated skin homeostatic functions and the delayed wound healing associated with ageing. In the present study, we focused on epidermal growth factor/epidermal growth factor receptor (EGF/EGFR) signalling and fibroblast growth factor-2/fibroblast growth factor receptor (FGF2/FGFR) signalling to analyse the age-related changes. Immunohistological analysis revealed that the expressions of EGFR and FGFR1 declined in IFE-SCs and DSCs with age, respectively. Additionally, IFE-SCs and DSCs isolated from the skin samples of elderly subjects exhibited lowered responsiveness to EGF and FGF2, respectively. These results suggest that the lowered responsiveness of the skin stem cells to growth factors may be a factor involved in the age-related deterioration of skin regenerative functions during wound healing and skin homeostatic functions. We hope that homeostatic and wound healing functions in the skin could be maintained if the decreased expressions of EGFR and FGFR1 in IFE-SCs and DSCs, respectively, can be suppressed.

UVA causes dysfunction of ETBR and BMPR2 in vascular endothelial cells, resulting in structural abnormalities of the skin capillaries.

BACKGROUND: Capillary structural abnormalities cause skin disorders. Mottled redness, i.e., skin redness unevenness, may appear on the sun-exposed skin, suggesting capillary structural abnormalities, although its mechanism remains unclear. OBJECTIVE: To observe the capillary structures in the sun-exposed skin where skin redness unevenness is likely to occur, and clarify the mechanism of capillary structural abnormalities. METHODS: The tissue structures in the skin with skin redness unevenness were observed by LC-OCT. Subsequently, immunostaining of the sun-exposed skin where skin redness unevenness is often observed, was performed. Vascular endothelial cells were UV-irradiated to analyze the expression and functions of genes involved in the capillary structures and morphogenesis. RESULTS: The skin with skin redness unevenness exhibited scattering of dilated tubular tissue and disturbance of distribution uniformity. Immunostaining of the sun-exposed skin that were more likely to be exposed to UV rays also revealed similarly disorder of capillary structures. In addition, UVA-irradiated vascular endothelial cells exhibited increased expression of ETBR, involved in telangiectasia, decreased expression of BMPR2, involved in the morphogenesis and maintenance of the blood vessels, and reduced migration of the capillaries. CONCLUSION: UV rays alter ETBR and BMPR2 expression in the skin capillaries, and cause partial dilation and decreased migration, resulting in capillary structural abnormalities and causing skin redness unevenness.

Clinical Usefulness of a Modified Mohs' Technique and Topical Application of Zinc Oxide Powder for Treating Skin Infiltration Caused by Unresectable Malignant Tumors.

Background: Infiltrative lesions of the skin caused by unresectable malignant tumors reduce the quality of life of patients significantly due to the presence of bleeding, exudate, pain, and/or malodor. Objective: We compared the efficacy of a modified Mohs' technique and topical application of a starch powder containing zinc oxide as palliative treatments for skin lesions caused by unresectable tumors in our hospital. Design: This is a retrospective study. Settings/Subjects: This study included nine patients who were treated for skin-infiltrating lesions caused by unresectable malignant tumors at our hospital in Japan from April 2008 to December 2019. Measurements: Mohs' paste or zinc oxide powder (50%) was applied to the infiltrative skin lesions. Arterial embolization was performed before the application of the Mohs' paste for patients at risk for arterial hemorrhage. Patients were evaluated for pain, tumor size, bleeding, wound exudate, and malodor. Results: Both treatments were useful for alleviating symptoms, such as tumor size, local bleeding, malodor, and exudate in patients with unresectable malignant tumors. Pain was reduced in patients treated with Mohs' paste for 1 hour as compared with those treated for 24 hours. Conclusions: Effective management of skin infiltrative lesions can be achieved by using a modified Mohs' technique, topical application of starch powder containing zinc oxide, and arterial embolization to reduce the vascularization of the tumors.

Gremlin 2 suppresses differentiation of stem/progenitor cells in the human skin.

INTRODUCTION: The skin is comprised of various kinds of cells and has three layers, the epidermis, dermis and subcutaneous adipose tissue. Stem cells in each tissue duplicate themselves and differentiate to supply new cells that function in the tissue, and thereby maintain the tissue homeostasis. In contrast, senescent cells accumulate with age and secrete senescence-associated secretory phenotype (SASP) factors that impair surrounding cells and tissues, which lowers the capacity to maintain homeostasis in each tissue. Previously, we found Gremlin 2 (GREM2) as a novel SASP factor in the skin and reported that GREM2 suppressed the differentiation of adipose-derived stromal/stem cells. In the present study, we investigated the effects of GREM2 on stem cells in the epidermis and dermis. METHODS: To examine whether GREM2 expression and the differentiation levels in the epidermis and dermis are correlated, the expressions of GREM2, stem cell markers, an epidermal differentiation marker Keratin 10 (KRT10) and a dermal differentiation marker type 3 procollagen were examined in the skin samples (n = 14) randomly chosen from the elderly where GREM2 expression level is high and the individual differences of its expression are prominent. Next, to test whether GREM2 affects the differentiation of skin stem cells, cells from two established lines (an epidermal and a dermal stem/progenitor cell model) were cultured and induced to differentiate, and recombinant GREM2 protein was added. RESULTS: In the human skin, the expression levels of GREM2 varied among individuals both in the epidermis and dermis. The expression level of GREM2 was not correlated with the number of stem cells, but negatively correlated with those of both an epidermal and a dermal differentiation markers. The expression levels of epidermal differentiation markers were significantly suppressed by the addition of GREM2 in the three-dimensional (3D) epidermis generated with an epidermal stem/progenitor cell model. In addition, by differentiation induction, the expressions of dermal differentiation markers were induced in cells from a dermal stem/progenitor cell model, and the addition of GREM2 significantly suppressed the expressions of the dermal differentiation markers. CONCLUSIONS: GREM2 expression level did not affect the numbers of stem cells in the epidermis and dermis but affects the differentiation and maturation levels of the tissues, and GREM2 suppressed the differentiation of stem/progenitor cells in vitro. These findings suggest that GREM2 may contribute to the age-related reduction in the capacity to maintain skin homeostasis by suppressing the differentiation of epidermal and dermal stem/progenitor cells.

Successful rechallenge therapy for BRAF/MEK inhibitor-resistant multiple brain metastases of melanoma.

Combination therapy with BRAF and MEK inhibitors (BRAFi/MEKi) have dramatically improved prognosis among patients with BRAF-mutant metastatic melanoma compared with traditional treatment, such as chemotherapy. However, resistance to these targeted agents occurs invariably, thereby limiting their clinical efficacy. Recently, it has been reported that the ligand-independent phosphorylation of erythropoietin-producing hepatocellular receptor A2 (EphA2) at Ser-897 signaling is a driver of BRAF inhibitor resistance in melanoma. A melanoma patient with multiple metastases was treated with dabrafenib plus trametinib therapy and maintained complete remission for more than 2 years. As brain metastasis occurred, we had switched to nivolumab plus ipilimumab therapy. However, new lesions were observed after four cycles of nivolumab plus ipilimumab therapy, she was rechallenged with encorafenib plus binimetinib therapy, and she maintained progression-free status for more than 7 months. We performed immunohistochemical staining of EphA2, phospho-EphA2 (p-EphA2; Ser-897), and epidermal growth factor receptor (EGFR) of melanoma cells before and/or after dabrafenib and trametinib therapy. Immunohistochemical examination showed higher expression of EphA2, p-EphA2, and EGFR in the melanoma cells after dabrafenib plus trametinib therapy as compared with that before therapy. Our results may indicate that EphA2, p-EphA2, and EGFR can be critical factors for resistance and reversible response of BRAFi/MEKi in metastases of melanoma. Our case presents a possible treatment that can help overcome BRAFi/MEKi resistance and improve prognosis of melanoma.

Senescent cell removal via JAG1-NOTCH1 signalling in the epidermis.

Emerging evidence has pointed to the noxious effects of senescent cells in various tissues, and senescent cells in the epidermis are known to accumulate with age. We hypothesized that there is a mechanism by which senescent cells in the epidermis are preferentially removed and that the function of such removal mechanism declines as age increases. In this study, we investigated whether Notch signalling is involved in such senescent cell removal. We found that Notch1 receptor was expressed more highly in p16INK4a-positive senescent cells than in surrounding cells in human epidermis both in young and old subjects. On the other hand, the expression of its ligand JAG1 was decreased in the epidermis of aged subjects. When normal epidermal cells and UVB-irradiated senescent cells were mixed and three-dimensional reconstructed epidermis was developed in vitro, the senescent cells were preferentially removed from the basal layer and located in the upper layer. We also found that the depletion of senescent cells from the basal layer was suppressed by JAG1 knockdown in normal cells or using a Notch signalling inhibitor. From these results, Notch signalling may be involved in senescent cell removal in the epidermis and the age-related decrease of JAG1 expression in the basal layer may lead to accumulation of senescent cells owing to reduced activation of Notch signalling.

Efficacy and safety of treatment with anti-tumor necrosis factor-α drugs for severe impetigo herpetiformis.

Impetigo herpetiformis (IH) is a rare pustular dermatosis. It can be life-threatening for both the mother and fetus and often causes therapeutic problems. However, there is no specific guideline for the treatment of IH and the evidence regarding the efficacy of treatments for IH has not been established. Herein, we report two cases of IH, which were successfully treated with anti-tumor necrosis factor (TNF)-α drugs. The serum levels of the drugs in the infants and mothers were examined using enzyme-linked immunosorbent assay (ELISA). Case 1 was a 35-year-old, gravida 2, para 1, female patient in week 20 of pregnancy; she was treated with adalimumab (ADA) until delivery. Case 2 was a 26-year-old, gravida 1, para 0, female patient in week 30 of pregnancy; she was treated with certolizumab pegol (CZP) until delivery. In both cases, the skin lesions started regressing considerably after administration of the biologic agents. We examined the serum levels of the biologic agents in the mothers and infants using ELISA. In case 1, the ADA serum level in the infant was as high as that in the mother at birth; it then decreased below the lower limit of quantification at week 12 post-delivery. In case 2, the CZP serum level in the infant was below the lower limit of quantification at birth. In this report, we revealed that biologic agents could be an effective treatment for severe IH and that CZP treatment can be considered safe for the mothers and fetuses.

SASP-induced macrophage dysfunction may contribute to accelerated senescent fibroblast accumulation in the dermis.

Recently, increasing attention has been paid to senescence-associated secretory phenotype (SASP), a phenomenon that senescent cells secrete molecules such as inflammatory cytokines and matrix metalloproteinases (MMPs), due to its noxious effects on the surrounding tissue. Senescent cells in the blood and liver are known to be properly depleted by macrophages. In the dermis, accumulation of senescent cells has been reported and is thought to be involved with skin ageing. In this study, to elucidate the clearance mechanism of senescent cells in the dermis, we focused on macrophage functions. Our co-culture experiments of senescent fibroblasts and macrophages revealed a two-step clearance mechanism: first, TNF-α secreted from macrophages induces apoptosis in senescent fibroblasts, and then, dead cells are phagocytosed by macrophages. Furthermore, it was suggested that SASP factors suppress both of the two steps of the senescent cell clearance by macrophages. From these findings, normally senescent cells in the dermis are thought to be removed by macrophages, but when senescent cells are excessively accumulated owing to oxidative stress, ultraviolet (UV) ray or other reasons, SASP was suggested to suppress the macrophage-dependent clearance functions and thereby cause further accumulation of senescent cells.