Deep Epidermis Research Articles

The transcription regulators ZNF750 and LSD1/KDM1A dampen inflammation on the skin’s surface by silencing pattern recognition receptors

The surface of the skin is continually exposed to pro-inflammatory stimuli; however, it is unclear why it is not constantly inflamed due to this exposure. Here, we showed undifferentiated keratinocytes residing in the deep epidermis could trigger a strong inflammatory response due to their high expression of pattern recognition receptors (PRRs) that detect damage or pathogens. As keratinocytes differentiated, they migrated outward toward the surface of the skin and decreased their PRR expression, which led to dampened immune responses. ZNF750, a transcription factor expressed only in differentiated keratinocytes, recruited the histone demethylase KDM1A/LSD1 to silence genes coding for PRRs (TLR3, IFIH1/MDA5, and DDX58/RIG1). Loss of ZNF750 or KDM1A in human keratinocytes or mice resulted in sustained and excessive inflammation resembling psoriatic skin, which could be restored to homeostatic conditions upon silencing of TLR3. Our findings explain how the skin's surface prevents excessive inflammation through ZNF750- and KDM1A-mediated suppression of PRRs.

ZNPs reduce epidermal mechanical strain resistance by promoting desmosomal cadherin endocytosis via mTORC1-TFEB-BLOC1S3 axis

Zinc oxide nanoparticles (ZNPs) are widely used in sunscreens and nanomedicines, and it was recently confirmed that ZNPs can penetrate stratum corneum into deep epidermis. Therefore, it is necessary to determine the impact of ZNPs on epidermis. In this study, ZNPs were applied to mouse skin at a relatively low concentration for one week. As a result, desmosomes in epidermal tissues were depolymerized, epidermal mechanical strain resistance was reduced, and the levels of desmosomal cadherins were decreased in cell membrane lysates and increased in cytoplasmic lysates. This finding suggested that ZNPs promote desmosomal cadherin endocytosis, which causes desmosome depolymerization. In further studies, ZNPs were proved to decrease mammalian target of rapamycin complex 1 (mTORC1) activity, activate transcription factor EB (TFEB), upregulate biogenesis of lysosome-related organelle complex 1 subunit 3 (BLOC1S3) and consequently promote desmosomal cadherin endocytosis. In addition, the key role of mTORC1 in ZNP-induced decrease in mechanical strain resistance was determined both in vitro and in vivo. It can be concluded that ZNPs reduce epidermal mechanical strain resistance by promoting desmosomal cadherin endocytosis via the mTORC1-TFEB-BLOC1S3 axis. This study helps elucidate the biological effects of ZNPs and suggests that ZNPs increase the risk of epidermal fragmentation.Graphical abstract

The First Evidence of Bacterial Foci in the Hair Part and Dermal Papilla of Scalp Hair Follicles: A Pilot Comparative Study in Alopecia Areata.

The role of the microbiome in hair follicle (HF) growth represents a growing field of research. Here, we studied the bacterial population in the scalp hair follicles of subjects with alopecia areata (AA). Two Healthy and two AA subjects, respectively (20–60 years old), were enrolled and studied regarding the microbial community in the subepidermal scalp compartments by means of a 4-mm biopsy punch. Samples were examined by 16S sequencing, histochemical staining (Gram’s method), and transmission electron microscopy (TEM). Bacterial foci were observed in the AA subjects’ follicles with both the two adopted complementary approaches (electron microscopy and Gram staining). Significant (p < 0.05) differences were also found in the three-layer biopsy samples (p < 0.05) regarding the bacterial population. In particular, in the deep epidermis and dermis levels, a significant (p < 0.05) lower abundance of Firmicutes and a higher abundance of Proteobacteria were found in AA samples compared to the healthy control. Firmicutes also showed a significant (p < 0.05) lower abundance in hypodermis in AA subjects. In addition, Enterobacteriaceae and the genera Streptococcus, Gemella, Porphyromonas, and Granulicatella were relatively more abundant in AA groups at the deep epidermis level. The Staphylococcus and Flavobacterium genera were significantly less abundant in AA samples than in controls in all three-layer biopsy samples (p < 0.05). In contrast, Veillonella and Neisseriaceae were relatively more abundant in the healthy control group compared to the AA sample. Therefore, higher alpha diversity was observed in all three-layer biopsy samples of AA patients compared to the control. In conclusion, our data suggest that tAA could be defined as a “hair disease associated with dysregulated microbiome-immunity axis of hair follicles”.

Treatment Effects Can Mimic Recurrent Extramammary Paget Disease in Perianal Skin.

The histologic differential diagnosis of perianal Paget disease includes malignant melanoma, pagetoid spread of squamous cell carcinoma, and secondary involvement by colorectal carcinoma. While consideration of these entities is useful when establishing a diagnosis, it does not apply when patients with Paget disease undergo surveillance for recurrent disease. Treatment of perianal Paget disease consists of a combination of surgical excision with skin grafts and topical chemotherapeutic agents that induce cytologic alterations in benign cells and simulate recurrent malignancy. To evaluate the therapy-related changes and possible diagnostic pitfalls in patients with Paget disease, we reviewed 412 posttreatment tissue samples from 3 women with primary perianal Paget disease who underwent wide excision, skin grafting, and topical 5-fluorouracil therapy. Biopsy samples from engrafted skin often displayed single and clustered cells with hyperchromatic nuclei dispersed in the deep epidermis. Similar cells were scattered throughout all levels of the epidermis in biopsy samples following topical chemotherapy. The abnormal cells were negative for cytokeratin 7 (CK7) and mucicarmine in both situations. Disease ultimately recurred in all patients; some Paget cells showed classic features with eosinophilic or mucinous cytoplasm and eccentric nuclei, whereas others were smaller with less conspicuous atypia. All Paget cells showed strong, membranous CK7 staining. In short, treatment of perianal Paget disease can elicit cytologic abnormalities in benign epithelial cells that simulate the cytologic features of recurrent disease, and can diminish the atypia of Paget cells. Immunohistochemical stains for CK7 can be helpful when evaluating surveillance samples from these patients.

Loss of ATP2A2 Allows Herpes Simplex Virus 1 Infection of a Human Epidermis Model by Disrupting Innate Immunity and Barrier Function

Destruction of epidermal barrier function associated with atopic dermatitis or Darier's disease often causes severe secondary skin infections. Patients with skin barrier disorders often repeatedly acquire Kaposi varicelliform eruption, which is caused by herpes simplex virus, but the underlying mechanisms and effective preventive methods have yet to be found. Viral infection through an impaired epidermal barrier can be prevented by enhancing innate immunity and/or inhibiting viral entry. In this study, we established a three-dimensional skin barrier dysfunction model by silencing ATP2A2, which is mutated in some Darier's disease patients. We confirmed the loss of desmosomes and presence of histopathological clefts in the suprabasal layer. Herpes simplex virus 1 applied to the stratum corneum infected the deep epidermis. An innate immune reaction was assessed by evaluating the expression of IFNB1 and related genes. Pretreatment with polyinosinic-polycytidylic acid alone or plus the antimicrobial peptide, LL37 enhanced IFN-β production and suppressed viral replication. Furthermore, topical application of a white petrolatum ointment containing heparin, which binds viral glycoproteins related to virus entry, strongly inhibited viral replication, probably by inhibiting invasion. Our human barrier-dysfunctional model will have future application for identifying the mechanism of Kaposi varicelliform eruption onset, preventive methods, and therapies.

Freeze-Dried Platelet Rich Plasma (PRP) Has Biological Activity in Acute Wound Healing of Animals, Inducing Significantly Angiogenesis

Background: Increasing prevalence of diabetes and obesity has registered a simultaneous increase in chronic wounds and defects in tissue repair. Recently PRP was described to be used in the treatment of chronic ulcers. PRP contains cytokines, chemokines and growth factors (GF) derived from platelets which induce molecular and cell mechanisms of natural wound healing. The possible use of GF derived from platelets, and the potential to prolong the shelf life of platelet concentrates, freeze-drying becomes one particularly suitable method to improve wound healing treatment. The use of lyophilized PRP appears to be interesting for greater convenience: only one blood collection, after hydration its soon ready for use, and also due to the highest concentration of bioactive molecules. This study aims to compare intra-lesional freeze-dried and fresh PRP for treatment of acute wound in a pre-clinic model.Methods: Fresh and freeze-dried PRP was prepared from two human platelet concentrate bags using double spin method. PRP characterization included platelet number and quantification of PDGF-AA, EGF, VEGF and TGF-β1 by Luminex (Millipore). Animal wound model was performed after shaving the dorsum of the rat, and a full-thickness excisional wound (1 cm2) was made to the level of the panniculus carnosus muscle. Thirty animals were divided according to the type o treatment in 3 groups: Fresh PRP (n=10), Freeze-dried PRP (FD-PRP) (n=10) and control saline (n=10). The animals received one perilesional application of 500 µL in the day of wound induction. The monitoring of wound closure was made through macroscopical analysis of wound size in days 3, 7 and 10 after wounding. Animals were sacrificed in the tenth day and the skin was removed for histology with hematoxilin-eosin and Masson´s Trichrome, and immunohistochemistry with α-actin smooth muscle for myofibroblasts and blood vessels, and quantified through image J.Results: The platelet number of PRP was 5714 x 103 cells / µL, presenting a high platelet recovery. The FD-PRP presented higher level of all GF when compared to fresh PRP from 1.64 to 3.72 folds. The application of PRP or FD-PRP did not induce significantly changes in wound healing kinetics compared to control during all evaluated days. The mean and standard deviation (SD) of area in D3 was 112.9 ± 16.6%, 107.9 ± 21.3 and 100.8 ± 30.2 for control, PRP and FD-PRP, respectively. In D7 it was 54.3 ± 28.9, 63.9 ± 22.8 and 61.6 ± 20.6 for control, PRP and FD-PRP, respectively. In D10 it was 9.9 ± 6.1, 13.9 ± 11.2, 7.7 ± 6.0 for control, PRP and FD-PRP, respectively. In immunohistochemistry of deep epidermis FD-PRP presented a significantly higher concentration of myofibroblasts in comparison with fresh PRP (16.61 ± 9.04 vs. 13.99 ± 14.07, p=0.0095). A significantly higher number of blood vessels was observed in the group treated with FD-PRP (in percentage of area) in comparison to the controls, both in superficial and deep regions of epidermis (0.43 ± 0.5 vs. 0.21 ± 0.22, P=0.01; 0.38 ± 0.44 vs. 0.24 ± 0.25, P=0.03, respectively).Discussion and conclusion: The most interesting result of this study was the increased number of blood vessels. VEGF plays a central role in promoting angiogenesis during wound repair. Previous studies demonstrated accelerated wound closure with collagen-binding VEGF topical treatment. However, the use of one growth factor has limited success and heterogeneity of clinical results, probably due to the need of multiple bioactive molecules that are necessary in the cascade of complexes events of healing. The use of multiples factors necessary to healing can orchestrated the physiological events resulting in chemotaxis, proliferation and differentiation of cells and the angiogenic process. The use of FD-PRP in this study of acute model of wounds showed positive results, especially in angiogenesis. The practicality and the improve in the shelf life of PRP have a great value in clinical practice and becomes very attractive, showing low cost, the possibility to increase the concentration of GF, various samples ready-to-use and a single blood collection. The investigation of FD-PRP in other clinical situations in which fresh PRP have been used is an interesting approach to be to evaluated to determine its effectiveness. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Staphylococcus aureus penetrate the interkeratinocyte spaces created by skin-infiltrating neutrophils in a mouse model of impetigo.

Impetigo is a bacterial skin disease characterized by intraepidermal neutrophilic pustules. Previous studies have demonstrated that exfoliative toxin producing staphylococci are isolated in the cutaneous lesions of human and canine impetigo. However, the mechanisms of intraepidermal splitting in impetigo remain poorly understood. To determine how staphylococci penetrate the living epidermis and create intraepidermal pustules invivo using a mouse model of impetigo. Three Staphylococcus aureus strains harbouring the etb gene and three et gene negative strains were epicutaneously inoculated onto tape-stripped mouse skin. The skin samples were subjected to time course histopathological and immunofluorescence analyses to detect intraepidermal neutrophils and infiltrating staphylococci. To determine the role of neutrophils on intraepidermal bacterial invasion, cyclophosphamide (CPA) was injected intraperitoneally into the mice to cause leucopenia before the inoculation of etb gene positive strains. In mice inoculated with etb gene positive S.aureus, intraepidermal pustules resembling impetigo were detected as early as 4h post-inoculation (hpi). Neutrophils in the epidermis were detected from 4hpi, whereas intraepidermal staphylococci was detected from 6hpi. The dimensions of the intraepidermal clefts created in mice inoculated with etb gene positive strains at 6hpi were significantly larger than those in mice inoculated with et gene negative strains. In CPA treated mice, staphylococci or neutrophils were not detected in the deep epidermis until 6hpi. Our findings indicate that intraepidermal neutrophils play an important role in S.aureus invasion into the living epidermis in a mouse model of impetigo.

Skin permeation of econazole nitrate formulated in an enhanced hydrophilic multiple emulsion.

Local delivery of imidazolic antifungals is limited by its extreme lipophilicity. Multiple emulsions (ME) are a potential vehicle to enhance the delivery of econazole nitrate (ECN), an antifungal targeted to deep-seated epidermal yeast infections. An 1% ECN hydrophilic ME was compared with a commercial formulation in terms of rheology, droplet size and in vitro antifungal activity against Candida species. Comparative in vitro drug release, human skin permeation and drug retention were investigated using vertical diffusion cells. Rheology demonstrated a pseudoplastic shear thinning with thixotropy facilitating skin residence. No significant aggregation or droplet size variations were observed during a 6-month stability storage. Both formulations exhibited similar release levels achieving asymptotic values in 5h. ECN skin permeation levels from the multiple emulsion resulted to be significantly higher than those of the commercial formulation, attributable to differences in formulation polarity and excipients composition. Conversely, similar drug accumulation levels in skin were obtained (40-130ppm). These concentrations resulted to be comparable with obtained MIC values (2-78ppm), confirming the in vitro antimicrobial efficacy of both formulations. A similar skin retention and a higher permeation rate over the existing formulations is considered an improved approach to target the drug to deep epidermis.

Cathepsin D Repairing Role in Photodamaged Skin Barrier

Backgrounds/Objectives: Cathepsin D plays an important part in maintaining a normal skin barrier. Our previous study found that cathepsin D decreased in chronic photodamaged skin. This study investigated the cathepsin D content change in the stratum corneum (SC) and the repairing role of cathepsin D in chronic photodamaged skin barrier via the application of cathepsin D gel. Methods: Cathepsin D gel (0.001%) was applied to chronic photodamaged (sun-exposed forearm) human skin on identical sites (1 cm²/area) twice daily for 2 weeks. At 30 min and at 1, 3, 7, and 14 days, skin hydration and transepidermal water loss (TEWL) average values were detected via noninvasive skin detection equipment. Cathepsin D and transglutaminase (TGase)-1 in the skin sublayers were separated and detected via tape stripping, ELISA and Western blot. Results: After 2 weeks of cathepsin D gel application, the skin moisture value increased from 86.8 ± 1.2 to 95.2 ± 2.7 (p < 0.05), while TEWL decreased from 17.88 ± 1.87 to 11.58 ± 2.14 (p < 0.05). Cathepsin D protein was detected in the upper epidermis (12.6 ± 2.6 ng/cm²), mid-epidermis (8.4 ± 0.8 ng/cm²) and deep epidermis (16.2 ± 2.6 ng/cm²) in the cathepsin D gel group compared to the control group (2.2 ± 0.7, 3.0 ± 1.1 and 3.85 ± 1.4 ng/cm², respectively; p < 0.05). TGase-1 enzyme expression was upregulated 2.54 ± 0.19 times in the matrix gel-treated skin. Conclusions: These data suggest that cathepsin D gel could increase the SC cathepsin D content and repair the epidermal barrier in chronic photodamaged skin. The mechanism might be related to increasing TGase-1 expression and activity. © 2014 S. Karger AG, Basel

Sucrose laurate-enhanced transcutaneous immunization with a solid-in-oil nanodispersion

A novel transcutaneous immunization system was developed using a solid-in-oil (S/O) nanodispersion, consisting of a nano-sized particle of a protein–surfactant complex dispersed in an oil vehicle. Permeability of the model antigen protein, ovalbumin, was enhanced by coating with sucrose laurate, which is a hydrophobic surfactant. The nanodispersion prepared with sucrose laurate induced a 5-fold increase in mouse antigen-specific antibody production compared with that observed using sucrose erucate, indicating that stability of the S/O nanodispersion in the epidermis plays a key role in enabling effective immunization. In spite of the coating with the surfactants, only fluorescence-labeled ovalbumin permeated the deep epidermis beneath the stratum corneum and was observed by laser scanning confocal microscopy. These findings will lead the way to an improved transcutaneous immunization system based on S/O nanodispersion.

Necrolytic migratory erythema associated with a glucagon‐producing primary hepatic neuroendocrine carcinoma in a cat

In humans, necrolytic migratory erythema (NME) is a syndrome with a characteristic skin rash that is associated most often with a pancreatic glucagonoma and is recognized as part of the glucagonoma syndrome. In veterinary medicine, NME (also called as superficial necrolytic dermatitis, hepatocutaneous syndrome or metabolic epidermal necrosis) has been described in dogs in association with chronic liver diseases or, less frequently, glucagonoma, but NME associated with glucagonoma has not previously been reported in cats. A 6-year-old male neutered domestic short hair cat was diagnosed with NME associated with a glucagon-producing primary hepatic neuroendocrine carcinoma (hepatic carcinoid). The cat presented with a 2 week history of vomiting and anorexia, and a 5-cm-diameter liver mass was detected by abdominal ultrasound. The cat exhibited general weakness, crusted skin lesions and pain in all four limbs. It was euthanized 11 months after the initial presentation. Histopathological review of the paw pads revealed the classic 'red, white and blue' lesion composed of parakeratotic hyperkeratosis, epidermal hydropic change and hyperbasophilia of the deep epidermis. The liver mass was diagnosed as a neuroendocrine carcinoma (hepatic carcinoid). Neoplastic cells were strongly immunoreactive for glucagon. This is the first case report of NME associated with a glucagon-producing primary hepatic neuroendocrine carcinoma in a cat.

Developing ultra deformable vesicular transportation of a bioactive alkaloid in pursuit of vitiligo therapy

ObjectiveTo develop transfersomal formulation integrated with piperine intended for vitiligo. MethodsFilm hydration technique was employed in the preparation of transfersomes. Modified diffusion cell, consistency tester were fabricated for ex vivo diffusion studies and spreadability studies respectively while tape stripping method was integrated with tissue extraction in the determination of tissue drug concentration. ResultsWhen film hydration technique was used for, ultradeformable vesicles (transfersomes) of piperine in soabean phosphatidylcholine was formed with (67.11±0.22) to (70.55±3.62) and (60.12±1.04) to (80.43±0.14) mean size (μ) and entrapment efficiency (%) respectively. Transfersomes are capable of crossing the pores in permeability barriers extremely efficient even if the transfersome radius (tr) is much greater than the pore size (rpore) ie., tr/rpore⩾ 0.25 the driven flux rate depends on the transdermal osmotic gradient. The vesicles describes elasto-mechanical character of vesicles while penetrating through the pores. The proviso is that the vesicular membrane elasticity is dynamically to the local stress by the external. Diffusion and Spreadability studies showed maximum diffusion when the lipid was kept minimum. Tape stripping and tissue extraction method for the tissue drug retention showed that (75.25±1.72)% drug was retained in the dermis. ConclusionSpan 80 was preferred over tween 80 in terms of dermal retention. Size and encapsulation was slightly altered by phosphatidylcholine concentration. The kinetics, efficiency and the transfersome mediated transport can be tailored for trans-epidermal, deep tissues and systemic depending on the vesicular composition, dose and form. Thus we have offered a successful drug delivery of piperine targeting the deep epidermis.

Recognition of Epidermal Transglutaminase by IgA and Tissue Transglutaminase 2 Antibodies in a Rare Case of &lt;em&gt;Rhesus&lt;/em&gt; Dermatitis

Tissue transglutaminase 2 (tTG2) is an intestinal digestive enzyme which deamidates already partially digested dietary gluten e.g. gliadin peptides. In genetically predisposed individuals, tTG2 triggers autoimmune responses that are characterized by the production of tTG2 antibodies and their direct deposition into small intestinal wall 1,2. The presence of such antibodies constitutes one of the major hallmarks of the celiac disease (CD). Epidermal transglutaminase (eTG) is another member of the transglutaminase family that can also function as an autoantigen in a small minority of CD patients. In these relatively rare cases, eTG triggers an autoimmune reaction (a skin rash) clinically known as dermatitis herpetiformis (DH). Although the exact mechanism of CD and DH pathogenesis is not well understood, it is known that tTG2 and eTG share antigenic epitopes that can be recognized by serum antibodies from both CD and DH patients 3,4. In this study, the confocal microscopy examination of biopsy samples from skin lesions of two rhesus macaques (Macaca mulatta) with dermatitis (Table 1, Fig. 1 and 2) was used to study the affected tissues. In one animal (EM96) a spectral overlap of IgA and tTG2 antibodies (Fig. 3) was demonstrated. The presence of double-positive tTG2+IgA+ cells was focused in the deep epidermis, around the dermal papillae. This is consistent with lesions described in DH patients 3. When EM96 was placed on a gluten-free diet, the dermatitis, as well as tTG2+IgA+ deposits disappeared and were no longer detectable (Figs. 1-3). Dermatitis reappeared however, based on re-introduction of dietary gluten in EM96 (not shown). In other macaques including animal with unrelated dermatitis, the tTG2+IgA+ deposits were not detected. Gluten-free diet-dependent remission of dermatitis in EM96 together with presence of tTG2+IgA+ cells in its skin suggest an autoimmune, DH-like mechanism for the development of this condition. This is the first report of DH-like dermatitis in any non-human primate.

Recognition of epidermal transglutaminase by IgA and tissue transglutaminase 2 antibodies in a rare case of Rhesus dermatitis.

Tissue transglutaminase 2 (tTG2) is an intestinal digestive enzyme which deamidates already partially digested dietary gluten e.g. gliadin peptides. In genetically predisposed individuals, tTG2 triggers autoimmune responses that are characterized by the production of tTG2 antibodies and their direct deposition into small intestinal wall. The presence of such antibodies constitutes one of the major hallmarks of the celiac disease (CD). Epidermal transglutaminase (eTG) is another member of the transglutaminase family that can also function as an autoantigen in a small minority of CD patients. In these relatively rare cases, eTG triggers an autoimmune reaction (a skin rash) clinically known as dermatitis herpetiformis (DH). Although the exact mechanism of CD and DH pathogenesis is not well understood, it is known that tTG2 and eTG share antigenic epitopes that can be recognized by serum antibodies from both CD and DH patients. In this study, the confocal microscopy examination of biopsy samples from skin lesions of two rhesus macaques (Macaca mulatta) with dermatitis (Table 1, Fig. 1 and 2) was used to study the affected tissues. In one animal (EM96) a spectral overlap of IgA and tTG2 antibodies (Fig. 3) was demonstrated. The presence of double-positive tTG2+IgA+ cells was focused in the deep epidermis, around the dermal papillae. This is consistent with lesions described in DH patients. When EM96 was placed on a gluten-free diet, the dermatitis, as well as tTG2+IgA+ deposits disappeared and were no longer detectable (Figs. 1-3). Dermatitis reappeared however, based on re-introduction of dietary gluten in EM96 (not shown). In other macaques including animal with unrelated dermatitis, the tTG2+IgA+ deposits were not detected. Gluten-free diet-dependent remission of dermatitis in EM96 together with presence of tTG2+IgA+ cells in its skin suggest an autoimmune, DH-like mechanism for the development of this condition. This is the first report of DH-like dermatitis in any non-human primate.

Fabrication of Microneedles Using Two Photon Polymerization for Transdermal Delivery of Nanomaterials

Microneedle devices for transdermal delivery of nanoscale pharmacologic agents were fabricated out of organically-modified ceramic (Ormocer) materials using two photon polymerization. Out-of-plane hollow microneedle arrays with various aspect ratios were fabricated using this rapid prototyping process. Human epidermal keratinocyte (HEK) viability on Ormocer surfaces fabricated using two photon polymerization was similar to that on control surfaces. Nanoindentation studies were performed to determine hardness and Young's modulus values for Ormocer materials. Microneedies were shown to enable more rapid distribution of the PEG-amine quantum dot solution to the deep epidermis and dermis layers of porcine skin than topical administration. Our results suggest that two photon polymerization may be used to create microneedle arrays for transdermal delivery of nanoscale pharmacologic agents.

Canine cutaneous epitheliotropic T‐cell lymphoma with vesiculobullous lesions resembling human bullous mycosis fungoides

The broad spectrum of clinical signs in canine cutaneous epitheliotropic T-cell lymphoma mimics many inflammatory skin diseases and is a diagnostic challenge. A 13-year-old-male castrated golden retriever crossbred dog presented with multifocal flaccid bullae evolving into deep erosions. A shearing force applied to the skin at the periphery of the erosions caused the epidermis to further slide off the dermis suggesting intraepidermal or subepidermal separation. Systemic signs consisted of profound weight loss and marked respiratory distress. Histologically, the superficial and deep dermis were infiltrated by large, CD3-positive neoplastic lymphocytes and mild epitheliotropism involved the deep epidermis, hair follicle walls and epitrichial sweat glands. There was partial loss of the stratum basale. Bullous lesions consisted of large dermoepidermal and intraepidermal clefts that contained loose accumulations of neutrophils mixed with fewer neoplastic cells in proteinaceous fluid. The lifted epidermis was often devitalized and bordered by hydropic degeneration and partial epidermal collapse. Similar neoplastic lymphocytes formed small masses in the lungs associated with broncho-invasion. Clonal rearrangement analysis of antigen receptor genes in samples from skin and lung lesions using primers specific for canine T-cell receptor gamma (TCRgamma) produced a single-sized amplicon of identical sequence, indicating that both lesions resulted from the expansion of the same neoplastic T-cell population. Macroscopic vesiculobullous lesions with devitalization of the lesional epidermis should be included in the broad spectrum of clinical signs presented by canine cutaneous epitheliotropic T-cell lymphoma.

Differentiated Vulvar Intraepithelial Neoplasia (VIN)

Abstract: Squamous intraepithelial lesions of the vulva, known as vulvar intraepithelial neoplasia, or VIN, are considered to be precursors of invasive squamous cell carcinoma. About a third of invasive squamous cell carcinomas are associated with human papillomavirus (HPV), but no link with HPV is detected in the remaining two thirds. Among intraepithelial lesions, the ratio of HPV-associated to non–HPV-associated lesions is reversed. HPV-associated VIN of the warty (condylomatous) and basaloid types is the most common and best-recognized form of VIN. A rare variant, pagetoid VIN, mimics Paget disease because the abnormal cells grow in a nested pattern and have pale cytoplasm. In this report, we present a case that illustrates the features of an important but often-unrecognized type of VIN, the differentiated or simplex type. It is frequently observed adjacent to non–HPV-associated squamous cell carcinomas, but it also occurs independent of invasive cancer. It differs from the more familiar HPV-associated Bowenoid types of VIN in that the most atypical cells are confined to the basal portion of the epithelium, and the more superficial epithelium consists of differentiated squamous cells. The pattern of differentiation is abnormal, as keratinization is often premature and exaggerated, keratin pearls are present in the deep epidermis or rete ridges, intercellular bridges are more prominent than usual, suprabasal cells have atypical nuclei, and there are suprabasal mitotic figures. Differentiated VIN is a precursor of keratinizing squamous cell carcinoma, and it is important to recognize it and differentiate it from nonneoplastic vulvar disorders such as squamous hyperplasia and lichen sclerosus.

Developments in topical retinoid therapy for acne.

Topical retinoic acid was introduced for acne treatment three decades ago. Since that time, researchers have discovered thousands of retinoids, originally defined as chemical analogs of vitamin A. After the identification of nuclear retinoid receptors in 1987, the definition of this class expanded to include molecules that bind to and activate such receptors. The receptor-selective retinoid agents, adapalene and tazarotene, were developed in the 1990s. Other innovations of the past decade include retinoid formulations and methods aimed at limiting retinoid absorption. Cutaneous irritation may be reduced without losing retinoid efficacy by inhibiting retinoid penetration into the deep epidermis and dermis. Examples include tretinoin in slow-release vehicles and the short-contact method of tazarotene gel therapy. Only trace amounts of adapalene are absorbed after topical application, perhaps explaining its relatively low irritancy. New formulations of existing agents, such as additional concentrations of tretinoin in microsphere gel and cream formulations of tazarotene, are now under investigation for acne. Current research focused on receptor selectivity holds the promise of yielding new retinoid molecules with improved benefits and safety.

Explanations for the clinical and microscopic localization of lesions in pemphigus foliaceus and vulgaris.

Patients with pemphigus foliaceus (PF) have blisters on skin, but not mucous membranes, whereas patients with pemphigus vulgaris (PV) develop blisters on mucous membranes and/or skin. PF and PV blisters are due to loss of keratinocyte cell-cell adhesion in the superficial and deep epidermis, respectively. PF autoantibodies are directed against desmoglein (Dsg) 1; PV autoantibodies bind Dsg3 or both Dsg3 and Dsg1. In this study, we test the hypothesis that coexpression of Dsg1 and Dsg3 in keratinocytes protects against pathology due to antibody-induced dysfunction of either one alone. Using passive transfer of pemphigus IgG to normal and DSG3(null) neonatal mice, we show that in the areas of epidermis and mucous membrane that coexpress Dsg1 and Dsg3, antibodies against either desmoglein alone do not cause spontaneous blisters, but antibodies against both do. In areas (such as superficial epidermis of normal mice) where Dsg1 without Dsg3 is expressed, anti-Dsg1 antibodies alone can cause blisters. Thus, the anti-desmoglein antibody profiles in pemphigus sera and the normal tissue distributions of Dsg1 and Dsg3 determine the sites of blister formation. These studies suggest that pemphigus autoantibodies inhibit the adhesive function of desmoglein proteins, and demonstrate that either Dsg1 or Dsg3 alone is sufficient to maintain keratinocyte adhesion.