The effects of systemic diseases, genetic disorders and lifestyle on keloids.

Keloid are a fibroproliferative disorder caused by abnormal healing of skin, specifically reticular dermis, when subjected to pathological or inflammatory scars demonstrating redness, elevation above the skin surface, extension beyond the original wound margins and resulting in an unappealing cosmetic appearance. The severity of keloids and risk of developing keloids scars are subjected to elevation by other contributing factors such as systemic diseases, general health conditions, genetic disorders, lifestyle and natural environment. In particular, recently, daily physical work interpreted into mechanical force as well as the interplay between mechanical factors such as stress, strain and stiffness have been reported to strongly modulate the cellular behaviour of keloid formation, affect their location and shape in keloids. Herein, we review the extensive literature on the effects of these factors on keloids and the contributing predisposing mechanisms. Early understanding of these participating factors and their effects in developing keloids may raise the patient awareness in preventing keloids incidence and controlling its severity. Moreover, further studies into their association with keloids as well as considering strategies to control such factors may help clinicians to prevent keloids and widen the therapeutic options.

[Scleromyxedema]. / Skleromyxödem.

Scleromyxedema or generalized diffuse lichen myxoedematosus is a rare mucinosis that is associated with monoclonal gammopathy and which frequently affects multiple extracutaneous organ systems. The pathogenesis of scleromyxedema has not been fully elucidated, but includes stimulation of glycosaminoglycan synthesis. The clinical course of scleromyxedema is chronic and often progressive, leading to severe morbidity and even death. The characteristic skin findings encompass multiple waxy papules often on indurated plaques, while thickening of skin leads to conspicuous folds on glabella and dorsal aspects of finger joints. Microscopical manifestations are dermal deposits of glycosaminoglycans between collagen bundles in reticular dermis, increased numbers of fibroblasts and fibrosis as well as loss of elastic fibers. Progressive skin involvement results in decreased mobility of the mouth and joints and even contractures. Extracutaneous manifestations occur in the musculoskeletal or cardiovascular system, in the gastrointestinal or respiratory tract, in the kidneys or in the central and peripheral nervous system. There are no in-label or evidence-based treatments available for scleromyxedema, but by expert consensus high-dose immunoglobulins are considered as treatment of choice, followed in case of insufficient efficacy by systemic glucocorticosteroids and then lenalidomide or thalidomide. In severe and refractory cases, autologous hematopoietic stem cell transplantation has been performed. Long-term maintenance treatment is usually required to prevent recurrences. Close interdisciplinary follow-up is recommended.

TAZ acting as a potential pathogenic biomarker to promote the development of lichen planus.

BACKGROUND: Lichen planus is a chronic inflammatory disorder. Transcriptional coactivator with PDZ-binding motif (TAZ/WWTR1) is an important downstream effector of the Hippo pathway which regulates organ size and tissue homeostasis. But little is known about the role of TAZ in lichen planus so far. OBJECTIVE: To explore the expression of TAZ in lichen planus and normal skin, and to discover the relationship between TAZ expression and the clinical characteristics of lichen planus patients. METHODS: The method of immunohistochemistry was performed to quantify the expression of TAZ in 262 patients with lichen planus and 90 control tissues. Western blot and quantitative real-time reverse transcriptase-PCR (qRT-PCR) analysis were performed to examine and compare TAZ expression in 4 cases of fresh lichen planus lesions and normal skin tissues. RESULTS: TAZ was weakly expressed in the basal layers of the epidermis in normal skin tissues with a positive rate of 52.22% (47/90). But in lichen planus, TAZ was strongly expressed in almost the entire epidermis with a positive rate of 81.30% (213/262), and the difference between the two groups was statistically significant (p<0.05). Additionally, TAZ expression was significantly related to the location of the lichen planus, clinical phenotype, smoking, and alcohol preference (p<0.05). Western blot and qRT-PCR showed that the expression of TAZ in protein and mRNA levels in four cases of lichen planus lesions was significantly higher than that in normal skin tissues. CONCLUSION: TAZ may play a regulatory role in the occurrence and development of lichen planus, which might provide a new perspective for studying pathogenesis and theoretical treatment targets.

Reconstruction of dermal layers evaluated by high-frequency ultrasound following treatment for skin fibrosis.

Background: Lymphedema is a chronic, progressive clinical condition that evolves with intense fibrosis, the most advanced stage of which is stage III (lymphostatic fibrosclerosis). Aim: The aim of the present study was to show the possibility to reconstruct the dermal layers with the intensive treatment of fibrosis using the Godoy method. Case description: A 55-year-old patient with an eight-year history of edema of the lower limb of the leg had constant episodes of erysipelas, despite regular treatments. The edema progressed continually, associated with a change in the color of the skin and the formation of a crust. Intensive treatment (eight hours per day for three weeks) was proposed with the Godoy method. The ultrasound was performed and results revealed substantial improvement in the skin, with the onset of the reconstruction of the dermal layers. Conclusion: It is possible to reconstruct the layers of the skin in fibrotic conditions caused by lymphedema.

Ex Vivo Human Histology Fractional Treatment with a New CO2 Scanner: A Potential Application on Deep Scarring.

Background and Objectives: For many years, fully ablative laser treatments, particularly those performed with a carbon dioxide (CO2) laser, were regarded as the gold standard for resurfacing. This study's goal is to assess the depth that can be reached by a new CO2 scanner system, through a skin model with greater dermal thickness, to use in the treatment of deep scarring. Materials and Methods: Male human skin tissue was laser-treated using a CO2 fractional laser and a new scanning system, and all samples were fixed in 10% neutral buffered formalin, dehydrated using a series of crescent alcohol, embedded in paraffin, sectioned in series (4-5 µm thick), stained with haematoxylin and eosin (H&E), and then analysed under an optical microscope. Results: From the epidermis through the underlying papillary and reticular dermis to various depths of the dermis, microablation columns of damage and coagulated microcolumns of collagen were observed. The reticular dermis was fully penetrated up to 6 mm at higher energy levels (210 mJ/DOT), resulting in deeper tissue injury. Although the laser might penetrate further, the skin stops there, leaving just the fat and muscular tissue. Conclusions: The deep layers of the dermis can be penetrated by the CO2 laser system throughout the entire dermal thickness when using the new scanning system, suggesting that this laser's potential impact, at the selected settings, covers all skin targets required to perform superficial or deep treatments on any dermatological issue. Finally, patients who have problems, such as morbid scar-deep complications, which affect their quality of life, are more likely to profit from this innovative technique.

Analysis of optical absorption of photoaged human skin using a high-frequency illumination microscopy analysis system.

Skin is composed of different layers, including the stratum corneum, epidermal living layer and papillary and reticular dermis. Each has specific optical properties due to differences in their biological components. Alterations in the skin's cutaneous biological components resulting from photoaging caused by chronic exposure to UV light affect the deterioration of appearance associated with the skin's optical properties. Various methods for analysing cutaneous optical properties have been previously proposed, including mathematical models and computer simulations. However, these were insufficient to elucidate changes in each skin layer and comprehensively understand the skin's integrated optical properties. We focused on UV-induced yellowing of the facial skin. We evaluated site-specific optical absorption of human skin tissue sections to investigate the yellowish discoloration, which is suggested to be related to the photodamage process. The method includes our original technique of separating the transmitted and scattered light using high-frequency illumination microscopy, leading to microscopic analysis of the tissue's optical absorption in the regions of interest. In analysing the sun-exposed facial skin tissue sections, we successfully showed that dermal regions of aged skin have increased absorption at 450 nm, where yellowish colours are complemented. Furthermore, we confirmed that elastic fibres with observable histological disorder resulting from photodamage are a prominent source of high optical absorption. We detected changes in the skin's optical absorption associated with dermal degeneration resulting from photodamage using a novel optical microscopy technique. The results provide a base for the evaluation of optical property changes for both yellowing discoloration and other tissue disorders.

Increased anti-oxidative action compensates for collagen tissue degeneration in vitiligo dermis.

Vitiligo is a common depigmentation disorder characterized by the selective loss of melanocytes. In our daily clinic experience, we noticed that the skin tightness of hypopigmented lesions would be more evident in comparison to that of uninvolved perilesional skin in vitiligo patients. Therefore, we hypothesized that collagen homeostasis might be maintained in vitiligo lesions, irrespective of the substantial excessive oxidative stress that occurs in association with the disease. We found that the expression levels of collagen-related genes and anti-oxidative enzymes were upregulated in vitiligo-derived fibroblasts. Abundant collagenous fibers were observed in the papillary dermis of vitiligo lesions in comparison to uninvolved perilesional skin by electron microscopy. The production of matrix metalloproteinases that degraded collagen fibers was suppressed. The deposition of acrolein adduct protein, which is a product of oxidative stress, was significantly reduced in vitiligo dermis and fibroblasts. As part of the mechanism, we found upregulation of the NRF2 signaling pathway activity, which is an important defense system against oxidative stress. Taken together, we demonstrated that the anti-oxidative action and collagen production were upregulated and that the collagen degeneration was attenuated in vitiligo dermis. These new findings may provide important clues for the maintenance of antioxidant ability in vitiligo lesions.

Innovative Approaches and Advances for Hair Follicle Regeneration.

Pathological hair loss (also known as alopecia) and shortage of hair follicle (HF) donors have posed an urgent requirement for HF regeneration. With the revelation of mechanisms in tissue engineering, the proliferation of HFs in vitro has achieved more promising trust for the treatments of alopecia and other skin impairments. Theoretically, HF organoids have great potential to develop into native HFs and attachments such as sweat glands after transplantation. However, since the rich extracellular matrix (ECM) deficiency, the induction characteristics of skin-derived cells gradually fade away along with their trichogenic capacity after continuous cell passaging in vitro. Therefore, ECM-mimicking support is an essential prelude before HF transplantation is implemented. This review summarizes the status of providing various epidermal and dermal cells with a three-dimensional (3D) scaffold to support the cell homeostasis and better mimic in vivo environments for the sake of HF regeneration. HF-relevant cells including dermal papilla cells (DPCs), hair follicle stem cells (HFSCs), and mesenchymal stem cells (MSCs) are able to be induced to form HF organoids in the vitro culture system. The niche microenvironment simulated by different forms of biomaterial scaffold can offer the cells a network of ordered growth environment to alleviate inductivity loss and promote the expression of functional proteins. The scaffolds often play the role of ECM substrates and bring about epithelial-mesenchymal interaction (EMI) through coculture to ensure the functional preservation of HF cells during in vitro passage. Functional HF organoids can be formed either before or after transplantation into the dermis layer. Here, we review and emphasize the importance of 3D culture in HF regeneration in vitro. Finally, the latest progress in treatment trials and critical analysis of the properties and benefits of different emerging biomaterials for HF regeneration along with the main challenges and prospects of HF regenerative approaches are discussed.

Subcutaneous fat infiltration into the dermal layer induces wrinkle formation.

BACKGROUND: Wrinkles appear with aging, producing an aged impression, but the mechanism of wrinkle formation has not yet been fully elucidated. We recently reported that subcutaneous fat infiltrates into the dermal layer with aging and impairs skin elasticity, but the contribution of this process to wrinkle formation is still unclear. PURPOSE: We aimed to clarify the contribution of dermal fat infiltration to wrinkle formation by analyzing the relationship between them in the forehead of female volunteers. METHODS: We measured the severity of fat infiltration in the forehead of 29 middle-aged female volunteers by means of ultrasonography. Fixed wrinkles present when the eyes were closed and wrinkles transiently formed when the eyes were open were evaluated using a photograph-based 6-grade evaluation system for each type of wrinkle. RESULTS: Fat infiltration at the forehead area was observed similarly to that in the cheek area as we reported previously. We found that opening the eyes induced the formation of stable transient wrinkles, the grade of which was significantly related to fat infiltration severity. Furthermore, fat infiltration was also significantly related to the severity of fixed wrinkles. Moreover, the severity of transient wrinkles was significantly related to that of fixed wrinkles. CONCLUSIONS: Our results suggest that fat infiltration into the dermal layer enhances transient wrinkle formation during facial expression by impairing the ability of the skin to resist deformation, thereby promoting fixed wrinkle formation. Therefore, fat infiltration is a critical cause of wrinkle formation.

Papillary dermal elastolysis histopathology mimicking folliculotropic mycosis fungoides.

Papillary dermal elastolysis is a rare acquired disease of the elastic tissue that mainly affects elderly women with a clinical presentation of small firm papules in the neck, the supraclavicular areas and the upper back. Histopathologically, it is characteristic to find a complete or almost complete absence of elastic fibers in the papillary dermis with stains such as orcein or Verhoeff-Van Gieson. We present the case of an adult female patient presenting a clinical picture of years of evolution of elastic skin-colored papules on her neck, occasionally pruritic. Two biopsies were performed. In one of them an inflammatory infiltrate affecting the hair follicles was observed, and she was diagnosed with mycosis fungoides. The other biopsy showed a total absence of elastic fibers in the papillary dermis and was diagnosed as elastolysis of the papillary dermis. In early stages of papillary dermal elastolysis, a perivascular and periadnexal lymphocytic inflammatory infiltrate has been described, as is the case described above. It is important for dermatopathologist to know this atypical but possible presentation, as it may require a differential diagnosis with other entities such as follicular mycosis fungoides.

Prediction and Demonstration of Retinoic Acid Receptor Agonist Ch55 as an Antifibrotic Agent in the Dermis.

The prevalence of fibrotic diseases and the lack of pharmacologic modalities to effectively treat them impart particular importance to the discovery of novel antifibrotic therapies. The repurposing of drugs with existing mechanisms of action and/or clinical data is a promising approach for the treatment of fibrotic diseases. One paradigm that pervades all fibrotic diseases is the pathological myofibroblast, a collagen-secreting, contractile mesenchymal cell that is responsible for the deposition of fibrotic tissue. In this study, we use a gene expression paradigm characteristic of activated myofibroblasts in combination with the Connectivity Map to select compounds that are predicted to reverse the pathological gene expression signature associated with the myofibroblast and thus contain the potential for use as antifibrotic compounds. We tested a small list of these compounds in a first-pass screen, applying them to fibroblasts, and identified the retinoic acid receptor agonist Ch55 as a potential hit. Further investigation exhibited and elucidated the antifibrotic effects of Ch55 in vitro as well as showing antiscarring activity upon intradermal application in a preclinical rabbit ear hypertrophic scar model. We hope that similar predictions to uncover antiscarring compounds may yield further preclinical and ultimately clinical success.

[Verrucous exophytic tumor of the glans penis]. / Verruköser exophytischer Tumor der Glans penis.

A 59-year-old man presented with a growing tumor on the glans penis, which we excised. Histologically, there was an acanthotic epidermis under which the papillary dermis was filled with foamy macrophages, best seen in a CD 68 stain. Verruciform xanthoma was diagnosed. Knowledge of this benign diagnosis may prevent an overly hasty, aggressive approach, since the differential diagnosis of penile carcinoma requires much more radical therapy, and mutilating penile surgery is associated with considerable psychosexual distress for patients.

Cutaneous erythematous lupus with acneiform presentation.

We present a 57-year-old woman with cutaneous lupus erythematosus (CLE), initially treated as acne. She noted blemishes, including nodules and facial swelling for nine months associated with discrete itching of the ears. Examination showed multiple malar nodules, comedones, pustules, atrophic scars, and hyperpigmentation. A biopsy was performed and revealed atrophic epidermis, discrete hyperkeratosis, vacuolar degeneration of basal layer, basal membrane zone with upper dermal lymphohistiocytic inflammatory infiltrate and deep perivascular and peri-adenexal lymphocytes, vascular ectasia, and mucin deposits. The acneiform presentation of CLE is commonly underdiagnosed due to the similarity with inflammatory acne. Histopathologic diagnostic in acneiform lupus is of extreme importance. This case emphasizes the relevance of knowing the notable variety of presentations of CLE and considering this diagnosis.

A prospective dual-centre intra-individual controlled study for the treatment of burns comparing dermis graft with split-thickness skin auto-graft.

To investigate if donor and recipient site morbidity (healing time and cosmesis) could be reduced by a novel, modified split-thickness skin grafting (STSG) technique using a dermal component in the STSG procedure (DG). The STSG technique has been used for 150 years in surgery with limited improvements. Its drawbacks are well known and relate to donor site morbidity and recipient site cosmetic shortcomings (especially mesh patterns, wound contracture, and scarring). The Dermal graft technique (DG) has emerged as an interesting alternative, which reduces donor site morbidity, increases graft yield, and has the potential to avoid the mesh procedure in the STSG procedure due to its elastic properties. A prospective, dual-centre, intra-individual controlled comparison study. Twenty-one patients received both an unmeshed dermis graft and a regular 1:1.5 meshed STSG. Aesthetic and scar assessments were done using The Patient and Observer Scar Assessment Scale (POSAS) and a Cutometer Dual MPA 580 on both donor and recipient sites. These were also examined histologically for remodelling and scar formation. Dermal graft donor sites and the STSG donor sites healed in 8 and 14 days, respectively (p < 0.005). Patient-reported POSAS showed better values for colour for all three measurements, i.e., 3, 6, and 12 months, and the observers rated both vascularity and pigmentation better on these occasions (p < 0.01). At the recipient site, (n = 21) the mesh patterns were avoided as the DG covered the donor site due to its elastic properties and rendered the meshing procedure unnecessary. Scar formation was seen at the dermal donor and recipient sites after 6 months as in the standard scar healing process. The dermis graft technique, besides potentially rendering a larger graft yield, reduced donor site morbidity, as it healed faster than the standard STSG. Due to its elastic properties, the DG procedure eliminated the meshing requirement (when compared to a 1:1.5 meshed STSG). This promising outcome presented for the DG technique needs to be further explored, especially regarding the elasticity of the dermal graft and its ability to reduce mesh patterns.Trial registration: ClinicalTrials.gov Identifier (NCT05189743) 12/01/2022.

[Effect of deep dermal tissue dislocation injury on skin fibrosis in pig].

Objective: To explore the effect of deep dermal tissue dislocation injury on skin fibrosis in pig, in order to provide some theoretical basis for burn scar treatment. Methods: The experimental research method was applied. Six 2-month-old female Duroc pigs were taken. Fifteen operative areas on the right dorsum of pigs on which medium-thick skin grafts and deep dermal tissue slices were cut and re-implanted were included into dermal in situ reimplantation group, and fifteen operative areas on the left dorsum of pigs on which medium-thick skin grafts and deep dermal tissue slices were cut and the deep dermal tissue slice was placed under the fat layer were included into the dermal dislocation group. The hair growth in the operative areas on post-injury day (PID) 7, 14, and 21 and the cross-sectional structure on PID 14 were observed in the two groups. On PID 7, 14, and 21, the skin thickness (the distance from the epidermis to the upper edge of the fat), the dermal thickness (the distance from the lower edge of the epidermis to the upper edge of the fat, excluding the fibrotic tissue thickness between the dermis and the fat), and the fibrosis tissue thickness of the dermis-fat interface (from the lower edge of the deep dermis to the upper edge of the fat in dermal in situ reimplantation group and from the lower edge of the superficial dermis to the upper edge of the fat in dermal dislocation group) in the operative areas were measured and compared between the two groups; the fibrotic tissue thickness at the dermal cutting interface (from the lower edge of the superficial dermis to the upper edge of the deep dermis) in the operative areas in dermal in situ reimplantation group was measured and compared with the fibrotic tissue thickness at the dermal-fat interface. Sirius red staining was performed to observe and compare the type Ⅰ and Ⅲ collagen content in the dermal-fat interface in the operative areas between the 2 groups and between the dermal cutting interface and dermal-fat interface in the operative areas in dermal in situ reimplantation group. Immunohistochemical staining was performed to observe the positive expressions of proliferating cell nuclear antigen (PCNA), transforming growth factor ß1 (TGF-ß1), fibroblast growth factor 2 (FGF-2), and hepatocyte growth factor (HGF) in the operative areas in the two groups. The sample number was 6. Data were statistically analyzed with independent sample t test. Results: On PID 7, 14, and 21, the hairs in the operative areas in dermal in situ reimplantation group were denser than those in dermal dislocation group. On PID 14, the skin cross section in the operative areas in dermal dislocation group showed a "sandwich"-like structure, while the skin cross section in the operative areas in dermal in situ reimplantation group had normal structure. On PID 7, 14, and 21, the skin thickness in the operative areas in dermal dislocation group was (4 234±186), (4 688±360), and (4 548±360) µm, respectively, which was close to (4 425±156), (4 714±141), and (4 310±473) µm in dermal in situ reimplantation group (P>0.05); the dermal thickness in the operative areas in dermal dislocation group was significantly thinner than that in dermal in situ reimplantation group (with t values of -9.73, -15.85, and -15.41, respectively, P<0.01); the fibrotic tissue thickness at the dermal-fat interface in the operative areas in dermal dislocation group was significantly thicker than that in dermal in situ reimplantation group (with t values of 14.48, 20.58, and 15.67, respectively, P<0.01); there was no statistically significant difference between the fibrotic tissue thickness at the dermal-fat interface and the dermal cutting interface in the operative areas in dermal in situ reimplantation group (P>0.05). On PID 7, 14, 21, the type Ⅲ collagen content in the dermal-fat interface in the operative areas in dermal dislocation group was increased significantly compared with that in dermal in situ replantation group (with t values of 2.65, 0.61, and 7.39, respectively, P<0.05 or P<0.01), whereas there were no statistically significant differences in the type Ⅰ collagen content at the dermal-fat interface in the operative areas between the 2 groups (P>0.05) and the type Ⅰ and Ⅲ collagen content between the dermal-fat interface and the dermal cutting interface in the operative areas in dermal in situ reimplantation group (P>0.05). On PID 7, 14, and 21, PCNA, TGF-ß1, FGF-2, and HGF were positively expressed in the superficial dermis and adipose tissue in the operative areas in dermal dislocation group, while PCNA, TGF-ß1, FGF-2, and HGF were positively expressed in the superficial dermis, deep dermis, and adipose tissue in the operative areas in dermal in situ reimplantation group. Conclusions: Inadequate intrinsic thickness of dermal tissue is the key factor causing fibrosis, and the biological purpose of fibrosis is to "compensate" the intrinsic thickness of the skin. Besides, adipose tissue may also be an important component of fibrotic skin repair.

Surgical Treatment Using Artificial Dermis for Women with Locally Advanced Breast Cancer.

Physicians occasionally come across with patients with locally advanced breast cancer (LABC) bringing about distress, due to tumor growth, invasion to the skin, bleeding or an ill smell. Physicians often experience much difficulty in selecting and administering therapeutic option. The clinical courses of patient who had been treated with total resection of LABC and an attachment of artificial dermis (TERUDERMIS) were mentioned. Elimination of the symptoms derived from the tumors could be successfully accomplished for all of the patients. Except for one patients who initially had bone metastasis and died 13 months after operation, the other patients have been alive under preferable condition without any signs for tumor recurrence. The surgical resection and an attachment of artificial dermis is quite reliable and helpful for both patients and physicians in palliating symptoms and reducing care for infections and hemorrhage due to LABC.

Different inoculum of Leishmania braziliensis concentrations influence immunopathogenesis and clinical evolution in the ear dermis hamster model of cutaneous leishmaniasis.

The golden hamster (Mesocricetus auratus) is commonly used as a promising model for Leishmania braziliensis infection developing skin-ulcerated lesions. However, different protocols using high concentration of parasites inoculated in the footpad result in severe clinical disease. Here, we further investigate the outcome of the site of infection and concentration of L. braziliensis parasites inoculated on the immunopathogenesis and clinical evolution. Initially, hamsters were infected in the ear dermis or hind footpad with a concentration of 1 × 105 parasites. Animals infected in the ear dermis developed a disease, with an increased parasite load that more closely resembled human cutaneous leishmaniasis lesions comparing to the group infected in the footpad. Next, we evaluated if different parasite concentrations (104 , 105 and 106 ) inoculated in the ear dermis would impact the course and clinical aspects of infection. Hamsters infected with 104 and 105 parasites developed mild lesions compared to the group infected with 106 that presented severe and persistent lesions. The parasite load varied between the different parasite concentrations. The inflammatory response was more intense when infection was initiated with 106 parasites accompanied by an increased initial expression of IL-4, IL-10 and arginase in the lymph node followed by expression of both pro-and anti-inflammatory cytokines comparing to groups infected with 104 and 105 parasites. In conclusion, the number of parasites inoculated, and the initial site of infection could influence the inflammatory response, and clinical presentation. Our results suggest that the ear dermis infection model induces a chronic disease that relates to immunopathological aspects of CL natural infection.

Actin cable formation and epidermis-dermis positional relationship during complete skin regeneration.

Up to a certain developmental stage, a fetus can completely regenerate wounds in the skin. To clarify the mechanism of fetal skin regeneration, identifying when the skin switches from fetal-type wound regeneration to adult-type wound repair is necessary. We hypothesized that this switch occurs at several time points and that complete skin regeneration requires epidermal-dermal interactions and the formation of actin cables. We compared normal skin and wound morphology at each developmental stage. We examined two parameters: epidermal texture and dermal structure. We found that the three-dimensional structure of the skin was completely regenerated in full-thickness skin incisions made before embryonic day (E) 13. However, the skin texture did not regenerate in wounds made after E14. We also found that the dermal structure regenerates up to E16, but wounds created after E17 heal as scars with dermal fibrosis. By controlling the activity of AMP-activated protein kinase and altering actin cable formation, we could regulate scar formation in utero. These findings may contribute to therapies that allow complete skin regeneration without scarring.

Single-Cell RNA-seq Analysis Reveals Cellular Functional Heterogeneity in Dermis Between Fibrotic and Regenerative Wound Healing Fates.

Background: Fibrotic scars are common in both human and mouse skin wounds. However, wound-induced hair neogenesis in the murine wounding models often results in regenerative repair response. Herein, we aimed to uncover cellular functional heterogeneity in dermis between fibrotic and regenerative wound healing fates. Methods: The expression matrix of single-cell RNA sequencing (scRNA-seq) data of fibrotic and regenerative wound dermal cells was filtered, normalized, and scaled; underwent principal components analysis; and further analyzed by Uniform Manifold Approximation and Projection (UMAP) for dimension reduction with the Seurat package. Cell types were annotated, and cell-cell communications were analyzed. The core cell population myofibroblast was identified and the biological functions of ligand and receptor genes between myofibroblast and macrophage were evaluated. Specific genes between fibrotic and regenerative myofibroblast and macrophage were identified. Temporal dynamics of myofibroblast and macrophage were reconstructed with the Monocle tool. Results: Across dermal cells, there were six cell types, namely, EN1-negative myofibroblasts, EN1-positive myofibroblasts, hematopoietic cells, macrophages, pericytes, and endothelial cells. Ligand and receptor genes between myofibroblasts and macrophages mainly modulated cell proliferation and migration, tube development, and the TGF-ß pathway. Specific genes that were differentially expressed in fibrotic compared to regenerative myofibroblasts or macrophages were separately identified. Specific genes between fibrotic and regenerative myofibroblasts were involved in the mRNA metabolic process and organelle organization. Specific genes between fibrotic and regenerative macrophages participated in regulating immunity and phagocytosis. We then observed the underlying evolution of myofibroblasts or macrophages. Conclusion: Collectively, our findings reveal that myofibroblasts and macrophages may alter the skin wound healing fate through modulating critical signaling pathways.

Cutaneous malakoplakia with verruciform xanthoma in the same lesion.

Cutaneous malakoplakia (CM) is a rare, chronic, granulomatous disease characterized histopathologically by Michaelis-Gutmann bodies (MGB). Verruciform xanthoma (VX) is a rare, benign lesion characterized histopathologically by epithelial papillomatous hyperplasia, local hyperkeratosis with incomplete keratosis, infiltration of foam cells and inflammatory cells in the papillary dermis. We present an elderly Chinese man with CM and coexisting VX with histological confirmation of MGB.