Perilesional Normal Skin Research Articles

Abstract 761: The relationship between ANGPTL4 and epidermal malignant transformation

Abstract High body mass index (BMI) is a risk factor for several types of cancers. Although epidemiology suggests obesity is negatively associated with non-melanoma skin cancer (NMSC), bariatric surgery has been shown to reduce the risk, suggesting a possible role of adipose tissue in the initiation and promotion of skin cancer. To gain mechanistic insight into how adipose tissue drives cutaneous carcinogenesis, we cultured non-tumorigenic mouse keratinocytes (JB6 P+ cells) with or without factors released from murine visceral adipose tissue (mFTF) and performed RNA-Sequencing. Published work demonstrated mFTF induces anchorage-independent cell growth, a surrogate marker for malignant transformation. Transcriptomic analysis demonstrated a significant induction of Angptl4 mRNA in JB6 P+ cells cultured with mFTF for 3 and 8 hours compared to the vehicle-treated cells. ANGPTL4 is an endogenous inhibitor of lipoprotein lipase that modulates free fatty acid delivery to adipose tissue and oxidative tissues such as muscle and liver. The C-terminal protein demonstrates tumor-associated activities such as angiogenesis, metastasis, protection against anoikis, and enhancement of cell survival. Therefore, we hypothesized that the induction of this gene promotes malignant transformation. RNA-seq data was validated in multiple cell models, including primary keratinocytes with human adipose tissue. Immunohistochemistry was used to assess ANGPTL4 expression in 37 actinic keratosis (pre-malignant) and cutaneous squamous cell carcinoma (cSCC) from patients with different BMIs (18.6 - 49.5). Notably, ANGPTL4 was only observed in the suprabasal epidermal layers in normal skin. For samples containing both lesional and perilesional skin, there was an increase in ANGPTL4 expression in the lesional epidermis relative to the normal perilesional skin. Furthermore, ANGPTL4 expression increased from transition to actinic keratosis to cSCC in situ, suggesting that ANGTL4 is induced during malignant transformation as observed in our pre-clinical models. Interestingly, once cSCC developed an invasive component, ANGTPL4 expression was lost in the invasive keratinocytes but persisted in the in situ component. There was no association between ANGPTL4 expression and BMI in lesional tissue. These data suggest that targeting ANTPLT4 may be a novel therapy for the prevention of skin cancer and that ANGPTL4-high patients or cancer patients with obesity may be a critical demographic for potential risk assessment or therapeutic intervention. Future studies will determine the impact of knocking out ANGTPL4 in our models of malignant transformation. Citation Format: Nat Ato Yawson, Jonathan D. Diedrich, Karen T. Liby, Jesse Veenstra, Jamie Jenna Bernard. The relationship between ANGPTL4 and epidermal malignant transformation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 761.

Raman spectroscopy and mass spectrometry identifies a unique group of epidermal lipids in active discoid lupus erythematosus

Discoid lupus erythematosus (DLE) is the most common form of cutaneous lupus1. It can cause permanent scarring. The pathophysiology of is not fully understood. Plasmacytoid dendritic cells are found in close association with apoptotic keratinocytes inferring close cellular signalling. Matrix Associated Laser Desorption Ionisation (MALDI) combined with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) is an exquisitely sensitive combination to examine disease processes at the cellular and molecular level. Active areas of discoid lupus erythematosus were compared with normal perilesional skin using MALDI combined with FT-ICR-MS. A unique set of biomarkers, including epidermal lipids is identified in active discoid lupus. These were assigned as sphingomyelins, phospholipids and ceramides. Additionally, increased levels of proteins from the keratin, and small proline rich family, and aromatic amino acids (tryptophan, phenylalanine, and tyrosine) in the epidermis are observed. These techniques, applied to punch biopsies of the skin, have shown a distinctive lipid profile of active discoid lupus. This profile may indicate specific lipid signalling pathways. Lipid rich microdomains (known as lipid rafts) are involved in cell signalling and lipid abnormalities have been described with systemic lupus erythematosus which correlate with disease activity.

Targeting senescent dermal fibroblasts responsible for hyperactive melanocytes in melasma

Targeting senescent dermal fibroblasts responsible for hyperactive melanocytes in melasma

Dermoscopic Features of Perilesional Skin of Unstable Vitiligo: A Cross-Sectional Study

Objectives: Dermoscopy is a very useful tool in determining stability in vitiligo. Dermoscopic features of unstable vitiligo are trichrome appearance, comet tail appearance, star burst appearance, amoeboid pattern, nebular pattern, tapioca sago pattern and perifollicular hypopigmentation. Most studies are done on determining features of vitiligo lesions; however, there is lack of studies on dermoscopy in normal appearing perilesional skin. This would give an insight into the extent of the disease process, beyond the borders of skin lesions. We conducted a study on 100 unstable lesions of vitiligo and studied dermoscopic features in its perilesional skin. The objective of this study was to observe dermoscopic features of apparently normal perilesional skin in patients of unstable vitiligo. Materials and Methods: A cross-sectional study was conducted in a tertiary care centre in New Delhi. We evaluated perilesional skin of 100 unstable vitiligo lesions over a span of 1 year. The perilesional skin has been defined as area within 5 cm of the lesion. Dermoscopy was performed using DERMLITE 4 Dermoscope at 10X magnification with inbuilt white light and polarised light. Polarised light was used to study changes in the pigmentary network and other patterns. We looked for features such as pigment network, perifollicular pigmentation, presence of leukotrichia, microkoebner phenomenon and satellite lesions in the perilesional skin. Results: The study included a total of 100 unstable lesions. Majority of patients belonged to the age group of 18−30 years. Females outnumbered males (1.8:1). All cases had progressive disease and mean duration of disease was 12.07 ± 10. 85 years. Dermoscopic features of vitiligo were observed in 56% of patients even in normal appearing perilesional skin. The most common dermoscopic finding observed was reduced pigment network which was seen in 33% of cases. Perifollicular hypopigmentation and depigmentation were observed in 23 and two sites, respectively, while leukotrichia was seen at ten sites. Eight sites showed microkoebners phenomenon. Conclusion: The perilesional apparently normal skin also shows signs of disease activity in cases of unstable vitiligo. Hence, perilesional skin should also be examined carefully with the dermoscope and topical treatment and targeted phototherapy should aim at covering the normal looking perilesional skin as well, at least within 5 cm of the borders of the skin lesions. Importantly, the perilesional skin should also be examined before surgery.

Immunobullous Disorder: A Diagnostic Dilemma Faced at a Tertiary Care Centre in Kanyakumari, Tamil Nadu, India

Introduction: Immunobullous disorders are morphologically heterogenous and hence the differentiation between various subtypes is essential for proper treatment and prognosis. Prompt diagnosis needs clinicopathological concordance added with Immunofluorescence (IF) in particular Direct Immunofluorescence (DIF) study to avoid discrepancies. Aim: To study the clinicopathological profile along with immunological features and to analyse the utility of IF in particular DIF of immunobullous disorders. Materials and Methods: The present study was a single institution based cross-sectional observational hospital study done in the department of pathology in SreeMookambika Institute of Medical Sciences, Tamil Nadu over a period of one year (July 2019-August 2020) involving 70 outpatients in the department of dermatology with clinical evidence of bullous disorders. Two biopsies were taken from the patient, one from a newly formed bulla or vesicle for Haematoxylin and Eosin (H&E) stain and the other from a perilesional normal looking skin for DIF study. Statistical analysis was done by using SPSS software. Chi-square test was used for statistical analysis. A p-value of less than 0.05 was considered as statistically significant. However, the final diagnosis was arrived after considering clinical, bedside investigations, histopathology and DIF study. Results: Out of seventy (70) patients included in this study, the most common age group of distribution was between 51-60 years in a frequency of 22 (31.4%). Out of 70 patients, 39 patients were diagnosed with intraepidermal bullous disorders and 31 patients were diagnosed with subepidermal bullous disorders. The most common disorder diagnosed was based on clinical findings was Pemphigus Vulgaris (PV) 31 (44.3%) followed by Bullous Pemphigoid (BP) 23 (32.9%). The common disorder diagnosed based on histopathology was PV 33 (47.1%). Clinical and histopathological concordance was conclusive in 31 cases of PV. The percentage of diagnosis of DIF was positive in 67 (95.71%). Patients which reached to inconclusive (DIF was not definite) diagnosis was in only three patients. Conclusion: Since, in most of the cases there occurs an overlap in clinical and histopathological features, IF in particular, DIF plays a sensitive tool in confirming diagnosis as well as distinguishing immunobullous disorders from other disorders.

Angiotropic melanocytes: Possibly a distinctive finding in extra-facial acquired dermal melanocytosis.

Acquired dermal melanocytosis is a heterogenous group of hyperpigmented lesioins which predominantly involve the face. The aim of this study was to study the clinical presentation and histopathology of cases with extra-facial acquired dermal melanocytosis. Retrospective record analysis was performed between May 2016 to August 2019 to retrieve cases of extra-facial acquired dermal melanocytosis seen at the out-patient department of dermatology at the All India Institute of Medical Sciences, Jodhpur. Consecutive cases with histopathologically proven diagnosis of acquired dermal melanocytosis were included. Documentation of variation in clinical presentation and histopathologic findings was done in light of the existing literature. Overall, four cases of extra-facial acquired dermal melanocyosis (female:male = 1:3) were seen during the study period. The lone case on head and neck involved the ear lobule and peri-auricular area. The other three cases had involvement of the hand. The histopathology confirmed the diagnosis of dermal melanocytosis but revealed peculiar findings of angiotropic melanocytes and dilated capillaries. Small sample size and lack of comparison with perilesional normal skin were the limitations of this study. The findings of angiotropic melanocytes may be unique to extra-facial acquired dermal melanocytosis. This might indicate interaction between dermal melanocytes and capillary endothelial cells. This finding along with dermal capillary ectasia may indicate a possible role for vascular lasers in the management of these disorders.

Line field confocal optical coherence tomography: An adjunctive tool in the diagnosis of autoimmune bullous diseases.

Autoimmune bullous diseases (AIBDs) still represent a considerable a source of morbidity and mortality: early identification of a specific AIBD is often difficult due to overlapping clinical and/or laboratory features and time-consuming invasive laboratory tests. We aimed to investigate the potential role of a new imaging technology, line-field confocal optical coherence tomography (LC-OCT), in the non-invasive diagnosis of AIBDs. LC-OCT was performed at lesional, perilesional and contralateral healthy sites in 30 patients, before histology and direct immunofluorescence. LC-OCT examination was able to identify the level of split (subcorneal/suprabasal/subepidermal/sublamina densa), to provide detailed images of the bulla roof morphology and content (eg, erythrocytes/acantholytic cells/polymorphonucleates). Areas of intra/subepidermal detachment were also detected also at clinically normal perilesional skin sites. LC-OCT can support physicians, real time and at bed-site, in the differential diagnosis of various AIBDs and their mimickers. Moreover, it can be used for the identification of subclinical lesions and therapy tapering.

Increased expression of Toll-like receptor 7 and 9 in vitiligo melanocytes: a pilot study.

Toll-like receptors (TLRs) are expressed on human melanocytes, and play an important role in innate and acquired immunity. The role of TLRs in the pathogenesis of vitiligo has not been fully described. To investigate the expression of TLRs in melanocytes from patients with vitiligo and healthy controls (HCs). Primary cultured vitiligo and control melanocytes were obtained from perilesional normal skin of patients with generalized vitiligo and HCs. TLRs mRNA expression in melanocytes were determined by real-time reverse transcription PCR and protein expression by western blotting. Apoptosis was analysed using an annexin V-fluorescein isothiocyanate apoptosis detection kit, and tyrosinase activity and melanin content were measured by a modified dopachrome and colorimetric method. Interleukin (IL)-6, IL-8 and soluble cell adhesion molecule (sICAM)-1 expression were measured by ELISA. In vitiligo melanocytes, compared with control melanocytes, apoptosis rate, expression of TLR7 and TLR9 mRNA and protein, and production of IL-8, IL-6 and sICAM-1 were significantly increased, whereas tyrosinase activity and melanin content were significantly decreased. Our results suggest that the increased expression of TLR7 and TLR9 might correlate with melanocyte dysfunction in vitiligo.

Histopathological Features of Riehl Melanosis.

Histological features of Riehl melanosis have rarely been compared between lesional and perilesional normal skin and have not been precisely described using quantitative or immunohistochemical analysis or electron microscopic findings. To investigate the histopathological and immunohistochemical features of lesional and perilesional normal skin of patients with Riehl melanosis, we retrospectively evaluated the electronic medical records and skin biopsy specimens of 48 patients with Riehl melanosis. In addition, electron microscopy was performed on 1 case. Fontana-Masson staining for melanin and immunohistochemical staining for Melan-A, NKI/beteb, tyrosinase, and microphthalmia-associated transcription factor were performed. Although the difference was statistically insignificant, melanin pigment was increased in the epidermis of lesional skin compared with that of perilesional normal skin in patients. The number of melanocytes and their activity were significantly increased in lesional epidermal skin. Melanin pigment was also significantly increased in the lesional dermis. Pigmentary incontinence, basal cell liquefaction, dilated vessels, epidermal spongiosis, and colloid bodies were found in the lesional skin as well as in the perilesional normal skin to a lesser extent. Under electron microscopy of 1 randomly selected subject, many fibrocytes contained numerous melanosome particles in the cytoplasm of the lesional dermis. In perilesional normal skin, fibroblasts also contained melanosome particles; however, the number of melanosome-containing cells was less than that in lesional skin. Riehl melanosis is characterized by increased epidermal melanocytes and pigmentation, primarily involving the dermis, with histologically typical changes at the interface. Unlike that in other pigmentary diseases, most perilesional normal-appearing skin in Riehl melanosis also shows typical histopathological changes, although to a lesser extent.

Expressionof langerhans cell and plasmacytoid dendritic cell markers, and toll-like receptor 7/9 signaling pathway proteins in verruca vulgaris lesions.

Langerhans cells (LCs) and plasmacytoid dendritic cells (pDCs) play an important role in the cutaneous immune response to viral infection. Verruca vulgaris (VV) is a chronic benign disease caused by human papillomavirus (HPV) infection.To investigate the possible roles of LCs, pDCs and toll-like receptor (TLR)7/9 signaling pathways in the pathogenesis of VV, we detected the expression of CD1a, CD2AP, CD123, TLR7/9, IFN regulatory factor 7 (IRF7), and interleukin-1 receptor-associated kinase 1 (IRAK1) in VV lesions.The expression of CD1a, CD2AP, CD123, TLR7/9, IRF7, and IRAK1 in 20 VV lesions was tested by immunohistochemistry. The density and number of stained cells were compared between VV lesions and the perilesional normal skin.The density and number of CD1a-, CD2AP-, CD123-, TLR9-, and IRAK1-positive cells in the papillary layer of VV lesions were significantly higher than those in the perilesional normal skin (P < .05). There were no significant differences in the density and positive rate of CD1a+ cells in the epidermis and of TLR7+ and IRF7+ cells in the dermis between VV lesions and the perilesional normal skin at the edge (P > .05).In VV, the number of LCs increases only in the dermis, indicating that LC's antigen-presenting function might not be inhibited. The increased number of pDCs in VV lesions suggests that HPV infection may recruit the pDCs to the virus-infected epithelium. We speculate that the TLR7/9 downstream signaling pathway is not fully activated in VV, leading to difficulty of HPV removal and the relapse of HPV-infected lesions.

带状疱疹患者外周血CD4+ T淋巴细胞及皮损组织中自噬水平的检测

Objective To observe changes in expression of autophagy proteins in peripheral CD4+ T lymphocytes and the epidermis of skin lesions, as well as generation of autophagy vesicles in epidermal cells in skin lesions of patients with herpes zoster, and to explore the relationship between varicella-herpes zoster virus (VZV) infection and autophagy. Methods Totally, 35 patients with herpes zoster were enrolled from Department of Dermatology, General Hospital of Southern Theater Command of PLA between December 2017 and December 2018, including 20 males and 15 females. Their age ranged from 18 to 79 (59.23 ± 9.27) years, pain duration was 5.14 ± 2.28 days, and lesion duration (from the onset of the lesion to the clinic visit) was 3.45 ± 1.77 days. Flow cytometry was performed to determine the expression of autophagy proteins including microtubule-associated protein 1 light chain 3B (LC3B) , Beclin-1 and p62 in peripheral blood CD4+ T lymphocytes of these patients. Thirty healthy adults served as control group. Lesional skin tissues were obtained from 12 patients with herpes zoster, and perilesional normal skin tissues of the same patient served as the control. Immunohistochemical study was conducted to determine the expression of autophagy proteins LC3B, Beclin-1 and p62 in epidermal tissues, and transmission electron microscopy to observe the generation of autophagy vesicles in epidermal cells. Two independent-sample t-test was carried out for intergroup comparison. Results The expression rates of autophagy proteins LC3B and Beclin-1 in peripheral CD4+ T lymphocytes were significantly higher in the herpes zoster group (61.23% ± 7.61%, 35.84% ± 4.22%, respectively) than in the control group (36.56% ± 4.27%, 15.34% ± 1.89%, respectively; t = 15.75, 24.56 respectively, both P < 0.01) , while the expression rate of p62 (5.75% ± 0.67%) was significantly lower in the herpes zoster group than in the control group (10.03% ± 1.15%, t = 18.65, P < 0.01) . Among the 12 patients with herpes zoster, the expression levels of LC3B and Beclin-1 in the epidermis were significantly higher in the skin lesions than in the perilesional normal skin tissues (t = 2.86, 4.58, P < 0.05) , but the expression level of p62 was significantly lower in the skin lesions than in the perilesional normal skin tissues (t = 2.43, P < 0.05) . Transmission electron microscopy showed formation of autophagy vesicles containing virus particles in epidermal cells in the skin lesions of 12 patients with herpes zoster, and vesicle counts were significantly higher in the skin lesions than in perilesional normal skin tissues (t = 9.67, P < 0.01) . Conclusion The autophagy level was elevated in peripheral CD4+ T lymphocytes and epidermis of skin lesions of patients with herpes zoster. Key words: Herpes zoster; Herpesvirus 3, human; Autophagy; CD4-positive T-lymphocytes; Host-pathogen interactions; LC3B; Beclin-1; p62

Histopathological comparison of lesional and perilesional skin in melasma: A cross-sectional analysis

Melasma is a common acquired hyperpigmentary disorder of the sun exposed skin, especially the face. The pathogenesis is unclear but interplay between genetic factors, hormones and ultraviolet radiation is important. We have evaluated the histological characteristics of melasma and compared the findings with adjacent normal skin. Skin biopsies were taken from both melasma and the surrounding perilesional normal skin in 50 Indian women. The sections were stained with hematoxylin and eosin, Fontana-Masson and Verhoeff-Van Gieson stains. Biopsy from melasma showed significant epidermal atrophy, basal cell hyperpigmentation and solar elastosis when compared with the perilesional skin. We found that the proportion of pendulous melanocytes was significantly higher in the lesional biopsy compared with the perilesional biopsy (76% vs 42%, P < 0.001). Similarly, pigmentary incontinence and features of solar elastosis were significantly higher in the lesional skin compared with the perilesional skin. The characteristic histopathological features such as epidermal atrophy, basal cell hyperpigmentation and solar elastosis suggest the role of chronic sun exposure in the pathogenesis of melasma. Presence of pendulous melanocytes is a characteristic feature of melasma. The presence of pendulous melanocytes may have prognostic implications in melasma.

Senescent fibroblasts in melasma pathophysiology.

It has been proposed that melasma is a photoageing skin disorder. The photoaged fibroblasts have been suggested as an important source of melanogenic factors which are involved in the regulation of pigmentation. To investigate whether melasma includes senescent cells, lesional and perilesional normal skin from 38 melasma patients was assessed using a cell senescence marker, p16INK4A . The results showed that lesional dermal skin had more p16INK4A -positive senescent cells than perilesional skin. The impact of senescent fibroblasts was further investigated in a pilot study using radiofrequency (RF) intervention for melasma. It showed that the RF therapy decreased the number of senescent cells with increased expression of procollagen-1, which were associated with reduced epidermal pigmentation. This leads us to the speculation that senescent fibroblasts may contribute to drive melasma and might be considered as a potential therapeutic target.

Enhanced expression of nidogen 1 around the nest of basal cell carcinoma compared with that around squamous cell carcinoma.

Basal cell carcinoma (BCC) is a malignant skin tumor originating from cells of the epidermal basal layer and adnexal epithelium, especially in sun-exposed areas. Unlike squamous cell carcinoma (SCC), BCC has a propensity to grow only locally possibly due to differences in the surrounding microenvironment including the basement membrane (BM) and stroma. To investigate the components constituting the BM and surrounding connective tissue in BCC and SCC, we analyzed the expression of BM proteins, nidogen 1 (NID1) and type IV collagen (COL4). We compared the immunohistochemical expressions of NID1 and COL4 among tumor specimens from BCC, SCC and its precancerous condition, actinic keratosis (AK), (n = 5 each condition). The expressions of NID1 and COL4 were both decreased around the tumor nest of SCC. In contrast, the expressions of both NID1 and COL4 around the nest of BCC were much higher than in the peri-lesional normal skin not only at the BM, but also in the surrounding stromal tissue. Our findings imply that the surrounding stromal cells of BCC, but not SCC or AK, excessively produce NID1 and COL4, which may be involved in preventing BCC cells from destroying the BM and invading the dermis.

Expression and activity of cathepsin L2 and its effect on the degradation of melanosomes in skin lesions of seborrheic keratosis

Objective To determine the expression of cathepsin L2 (CTSL2) and evaluate its activity in skin lesions of seborrheic keratosis (SK) , to observe the ultrastructural changes of melanosomes in the skin lesions of SK, and to estimate the effect of CTSL2 on the degradation of melanosomes. Methods Twenty patients with SK were enrolled from the Department of Dermatology, Renmin Hospital of Wuhan University. The lesional tissue and the perilesional normal skin were biopsied from each patient. Among 15 of the 20 patients, hematoxylin and eosin (HE) staining and Fontana-Masson silver staining were performed to observe the distribution of melanin granules, transmission electron microscopy (TEM) was conducted to observe the ultrastructural changes of melanosomes, and immunohistochemical staining was performed to estimate the cellular proliferative activity. RT-PCR and fluorogenic substrate cleavage assay were performed in the other 5 patients to determine the mRNA expression of CTSL2 and evaluate its activity, respectively. Sucrose density gradient ultracentrifugation was performed to isolate and purify melanosomes from the retinal pigment epithelium (RPE) harvested from a discarded eyeball of a 35-year old male patient with informed consent. The purified melanosomes were incubated with epidermal lysates of SK lesions, and TEM was used to observe the changes in the membrane structure of melanosomes. Statistical analysis was carried out by paired t test, and a P value < 0.05 was considered statistically significant. Results A large number of melanin granules were deposited in SK lesions, while the linear deposition of melanin granules was only seen in the basal layer of the normal skin. TEM showed that the percentage of damaged melanosomes was much higher in the normal skin (49.00% ± 4.00%) than in the SK lesions (24.33% ± 3.06%) (t= 8.49, P < 0.05) . RT-PCR revealed that the mRNA expression and activity of CTSL2 were both significantly lower in the SK lesions than in the normal skin (mRNA: 0.35 ± 0.09 vs. 0.43 ± 0.08, t= 3.17, P < 0.05; activity: 17.46 ± 0.45 vs. 28.78 ± 0.58, t= 34.29, P < 0.05) . Moreover, TEM also showed that the percentage of damaged melanosome was lower in the SK lesion lysate-treated group (32.33% ± 4.93%) than in the normal skin lysate-treated group (43.00% ± 2.65%, t= 3.30, P < 0.05) . Conclusion Decreased expression of CTSL2 in the SK lesions can affect the degradation of melanosomes by keratinocytes. However, whether CTSL2 directly takes part in the pathogenesis of SK or not is still needed to be further confirmed. Key words: Keratosis, seborrheic; Melanosomes; Cathepsin L

1230 IL17, IL33 and their relationship with skin barrier in melasma

Melasma is a chronic and relapsing disorder that negatively impacts the quality of life. Its pathogenesis is not entirely clear, but genetic factors, ultraviolet radiation, hormones, cellular interactions and inflammation are all involved. An abnormal skin barrier function has previously been described. Our objectives were to determine the cutaneous biophysical characteristics of malar melasma and the expression of Profilaggrin/Filaggrin and IL-17, IL-33. The melanin/erythema index, stratum corneum hydratation and transepidermal water loss (TEWL) were measured for lesional and perilesional normal skin of 20 malar melasma patients with photypes IV-V. Skin biopsies were taken from lesional and unaffected skin to evaluate filaggrin, profilaggrin, IL-17 and IL-33 by immunohistochemistry and RT-PCR. Melanin, erythema index, and hydratation were higher in lesional skin than in perilesional normal skin. No difference of basal TWEL levelwas found between lesional and normal skin.Thirty minutes after barrier perturbation, the recovery rate in melasma skin was apparently completed. A higher expression of Profilagrin/filagrin was found in the skin affected with melasma, as well as an increase of IL-17.< We observed a strong expression of IL-33 in apparently healthy skin from melasma patients which may suggest a subclinical chronic inflammation. Thus, in this condition there may be a link between inflammation / abnormal epidermal differentiation and the retention of melanin.

Senescent fibroblasts drive ageing pigmentation: ​A potential therapeutic target for senile lentigo.

Cutaneous ageing is an important extrinsic process that modifies the pigmentary system. Because cellular senescence is a fundamental ageing mechanism, we examined the role of senescent cells in ageing pigmentation.Methods: Biopsies obtained from senile lentigo and perilesional normal skin were assayed for a marker of cellular senescence, p16INK4A. To determine the secretory phenotypes of senescent fibroblasts, we performed microarray, RNA sequencing and methylation array analyses in senile lentigo and senescent fibroblasts. To further investigate the impact of senescent cells on ageing-related pigmentation, an intervention that targeted senescent cells using radiofrequency was performed.Results: In vivo, senescent fibroblasts accumulated at the sites of age-related pigmentation. Phenotype switching of the cells resulted in the repression of stromal-derived factor 1 (SDF1) by promoter methylation. SDF1 induced melanocyte differentiation via stromal-epithelial interactions, ultimately driving skin pigmentation. Furthermore, the elimination of senescent fibroblasts from pigmented skin using radiofrequency was accompanied by skin lightening, rendering it a potential target for treatment.Conclusion: Aged pigmented skin contains an increasing proportion of senescent fibroblasts. Cells with phenotype switching exhibited a loss of SDF1, which stimulates the melanogenic process and thereby contributes to aging pigmentation. These data may promote the development of new therapeutic paradigms, such as a stroma-targeting therapy for pigmentary disorders.

Reflectance confocal microscopy characteristics of childhood hypopigmented lichen striatus

Objective To investigate reflectance confocal microscopy (RCM) characteristics of childhood hypopigmented lichen striatus. Methods RCM was performed to image skin lesions and perilesional normal skin in 11 children with hypopigmented lichen striatus. Then, confocal microscopic findings of the skin lesions were compared with pathological findings. Results Histopathological examination of the skin lesions showed mild intercellular and intracellular edema, thickening of prickle cell layer to different extent, local liquefaction degeneration of basal cells, and perivascular infiltration of plenty of lymphocytes and a few melanophages in the superficial dermis. RCM horizontal images showed multifocal liquefaction degeneration of basal cells, which caused indistinct dermo-epidermal junction, incomplete or unclear dermal papillary rings, infiltration of many highly refractive melanophages and slightly to moderately refractive inflammatory cells in papillary and superficial dermis. Conclusion RCM characteristics can serve as strong evidences for the diagnosis and differential diagnosis of childhood hypopigmented lichen striatus. Key words: Hypopigmentation; Microscopy, confocal; Pathologic processes; Lichen striatus albus

Assessment of skin pigmentation by confocal microscopy: Influence of solar exposure and protection habits on cutaneous hyperchromias.

Cutaneous hyperchromias are disorders of skin pigmentation involving an increase of melanin production and its irregular accumulation in skin cells. It is known that the use of sunscreens helps to prevent changes in the skin pigmentation pattern, but the structural and morphological alterations that occur in the different types of hyperpigmentations need better elucidation. To assess the influence of solar exposure and protection habits on the pattern of skin pigmentation using reflectance confocal microscopy (RCM). Forty volunteers aged 18-39 years with skin hyperpigmentation participated in the study. Skin characterization was performed by imaging techniques and by assessing the habits of solar exposure and protection by applying questionnaires to the volunteers. RCM was used to record sequences of confocal sections at areas of interest and to examine cell shape and brightness in the basal cell layer of the lesion and in normal perilesional skin. Furthermore, high-resolution images were obtained for analysis of the spots. Sunlight influences the number and location of spots as the face of volunteers with higher solar exposure was covered with spots, whereas volunteers with less exposure had fewer spots located in the nose and cheeks region due to greater exposure of these areas to the sun. The data showed the importance of sun protection for preventing changes in the pattern of skin pigmentation, and RCM proved to be an important tool for skin characterization.

Two histopathological patterns of postinflammatory hyperpigmentation: epidermal and dermal.

Postinflammatory hyperpigmentation (PIH) commonly occurs, but the histopathological features are not well characterized. A total of 21 PIH patients' medical charts were reviewed. Punch biopsies from lesional and perilesional normal skin were performed. Sections were stained with hematoxylin-eosin, Fontana-Masson, NKI/beteb, microphthalmia-associated transcription factor (MITF), CD68, c-kit, factor XIIIa, MMP-2 and MMP-9. Fontana-Masson-stained sections suggested two obvious PIH groups: epidermal (13 cases) and dermal (8 cases) pigmentation. The epidermal pigment group had increased epidermal basal pigmentation. The dermal pigment group had marked pigmentation within the upper dermis and decreased epidermal pigmentation. More intense perivascular lymphocytic infiltration was observed in the dermal pigment group. NKI/beteb levels were increased in lesional skin in both groups. The numbers of MITF+ melanocytes were not different between lesional and perilesional normal skin in either group. The expression of CD68 and c-kit was significantly higher in the dermis of lesional skin than in normal skin in the dermal pigment group. MMP-2 expression was upregulated in lesional skin in both groups. PIH patients can be classified into two histopathological groups: epidermal and dermal pigmentation. The dermal pigment group showed decreased levels of epidermal pigmentation. This study provides histopathological information that can improve the treatment of PIH.