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.     

Selenium and Psoriasis

Psoriasis is a chronic, immune-mediated skin disease characterized by production of reactive oxygen species due to the activation of tumor necrosis factor alpha (TNF-??), which is thought to be an important factor in inducing and maintaining psoriatic lesions. As an external factor, ultraviolet B (UVB) radiation stimulates TNF-?? production and secretion by human keratinocytes in vitro and can also reach the upper dermis and suppress endothelial cells in vitro. The selenium level in psoriatic patients has been found to be lower than expected, but studies on its role in the pathogenesis of the disease are scarce. Selenium can influence immune response by changing the expression of cytokines and their receptors or by making immune cells more resistant to oxidative stress. It was reported that selenium supplementation had inhibitory effects on TNF-?? levels in patients with psoriasis, but the details are not completely elucidated. Selenium compounds are also known to prevent the in vitro release of UVB-induced proinflammatory cytokines by inhibition of mRNA in human keratinocytes. In the present review, the protective role of selenium in oxidative stress, lesions, and immune system regulation in patients with psoriasis is summarized.     

Deepithelialized turnover flaps in burns

Acute and chronic burns leave behind a full-thickness defect that always requires a flap cover. Such defects are common in electrical burn injuries of the limbs. This paper deals with 35 patients with full-thickness defects following burns in whom deepithelialized turnover dermis flaps and deepithelialized turnover flaps with deep fascia have been used. This flap is an extension of Hynes's reversed dermis graft and Smahel's deepithelialized turnover flap where there is a larger area of blood supply on the deeper aspect of the dermis. If a good hinge is provided for safe blood supply, such a flap settles well in the defect, and cumbersome multistaged procedures can be avoided. If there is less fatty tissue in the area of flap used, then reversed dermis flaps are ideal because split-skin graft take is good. When there is a lot of fatty tissue on the undersurface of dermis, the fascia is also included to make it a reversed fasciocutaneous flap to augment the blood supply and for better split-skin graft survival. Advantages of the procedure and complications are elaborated.     

Telocyte dynamics in psoriasis

The presence of telocytes (TCs) as distinct interstitial cells was previously documented in human dermis. TCs are interstitial cells completely different than dermal fibroblasts. TCs are interconnected in normal dermis in a 3D network and may be involved in skin homeostasis, remodelling, regeneration and repair. The number, distribution and ultrastructure of TCs were recently shown to be affected in systemic scleroderma. Psoriasis is a common inflammatory skin condition (estimated to affect about 0.1–11.8% of population), a keratinization disorder on a genetic background. In psoriasis, the dermis contribution to pathogenesis is frequently eclipsed by remarkable epidermal phenomena. Because of the particular distribution of TCs around blood vessels, we have investigated TCs in the dermis of patients with psoriasis vulgaris using immunohistochemistry (IHC), immunofluorescence (IF), and transmission electron microscopy (TEM). IHC and IF revealed that CD34/PDGFRα‐positive TCs are present in human papillary dermis. More TCs were present in the dermis of uninvolved skin and treated skin than in psoriatic dermis. In uninvolved skin, TEM revealed TCs with typical ultrastructural features being involved in a 3D interstitial network in close vicinity to blood vessels in contact with immunoreactive cells in normal and treated skin. In contrast, the number of TCs was significantly decreased in psoriatic plaque. The remaining TCs demonstrated multiple degenerative features: apoptosis, membrane disintegration, cytoplasm fragmentation and nuclear extrusion. We also found changes in the phenotype of vascular smooth muscle cells in small blood vessels that lost the protective envelope formed by TCs. Therefore, impaired TCs could be a ‘missed’ trigger for the characteristic vascular pathology in psoriasis. Our data explain the mechanism of Auspitz's sign, the most pathognomonic clinical sign of psoriasis vulgaris. This study offers new insights on the cellularity of psoriatic lesions and we suggest that TCs should be considered new cellular targets in forthcoming therapies.     

Histopathology of chromoblastomycosis

Summary A study aimed at determining the histopathologic appearance of chromoblastomycotic lesions was undertaken. Biopsies from 26 patients with the disease were examined. It was found that 23 cases (88.46%) exhibited the organized mixed mycotic granuloma — OMMA —, a granuloma modified by the presence polymorphonuclear neutrophils — PMN's. An equal proportion of cases exhibited pseudoepitheliomatous hyperplasia, with the epithelium playing an important role in the transepidermic elimination of the fungus. Healing of the lesions took place by fibrosis which was observed in 21 (80.77%) patients; this type of reaction was more common in the deeper areas of the dermis.     

Scabies masquerading as Letterer-Siwe's disease.

Letterer-Siwe''s disease was diagnosed from clinical appearance and initial assessment of a skin biopsy in a child with a 2-month history of skin rash. Fine erythematous papules were scattered on the trunk. The biopsy showed epidermal thickening and an inflammatory infiltrate chiefly in the upper layers of the dermis; deeper in the dermis the infiltrate was perivascular and periappendicular, histiocytes predominating in some areas and lymphocytes in others. A diagnosis of scabies was made after burrows were demonstrated on palms and soles and the mite of scabies was isolated from them.     

Monoclonal antibody analysis of skin in chronic murine graft vs host disease produced across minor histocompatibility barriers

Chronic graft vs host disease (GVHD) across minor histocompatibility barriers was produced in BALB/c mice by the injection of spleen cells from B10.D2 mice. Changes in the skin were analyzed in frozen sections using a panel of monoclonal antibodies detected by immunoperoxidase methods. Compared to control animals, a number of changes occurred in the skin of animals with chronic GVHD. In the epidermis, there were increased numbers of Thy-1-positive dendritic cells; keratinocytes expressed Thy-1 and Ia antigens. T lymphocytes appeared in both dermis and epidermis. In the early stages, cells with "helper" and "suppressor" phenotypes were present, while at later times "helper" cells remained in the epidermis and "suppressor" cells remained in the dermis. Cells bearing markers of macrophages were prominent in both dermis and epidermis after the second week. Of great interest was the appearance of spindle-shaped cells in the dermis which expressed Thy-1 and Ia. These cells resembled fibroblasts which may be activated to produce the excess collagen seen in the skin of chronic GVHD.     

Softenin,a Novel Protein That Softens the Connective Tissue of Sea Cucumbers through Inhibiting Interaction between Collagen Fibrils

The dermis in the holothurian body wall is a typical catch connective tissue or mutable collagenous tissue that shows rapid changes in stiffness. Some chemical factors that change the stiffness of the tissue were found in previous studies, but the molecular mechanisms of the changes are not yet fully understood. Detection of factors that change the stiffness by working directly on the extracellular matrix was vital to clarify the mechanisms of the change. We isolated from the body wall of the sea cucumber Stichopus chloronotus a novel protein, softenin, that softened the body-wall dermis. The apparent molecular mass was 20 kDa. The N-terminal sequence of 17 amino acids had low homology to that of known proteins. We performed sequential chemical and physical dissections of the dermis and tested the effects of softenin on each dissection stage by dynamic mechanical tests. Softenin softened Triton-treated dermis whose cells had been disrupted by detergent. The Triton-treated dermis was subjected to repetitive freeze-and-thawing to make Triton-Freeze-Thaw (TFT) dermis that was softer than the Triton-treated dermis, implying that some force-bearing structure had been disrupted by this treatment. TFT dermis was stiffened by tensilin, a stiffening protein of sea cucumbers. Softenin softened the tensilin-stiffened TFT dermis while it had no effect on the TFT dermis without tensilin treatment. We isolated collagen from the dermis. When tensilin was applied to the suspending solution of collagen fibrils, they made a large compact aggregate that was dissolved by the application of softenin or by repetitive freeze-and-thawing. These results strongly suggested that softenin decreased dermal stiffness through inhibiting cross-bridge formation between collagen fibrils; the formation was augmented by tensilin and the bridges were broken by the freeze-thaw treatment. Softenin is thus the first softener of catch connective tissue shown to work on the cross-bridges between extracellular materials.     

Spatiotemporal Evolution of Erythema Migrans,the Hallmark Rash of Lyme Disease

To elucidate pathogen-host interactions during early Lyme disease, we developed a mathematical model that explains the spatiotemporal dynamics of the characteristic first sign of the disease, a large (≥5-cm diameter) rash, known as an erythema migrans. The model predicts that the bacterial replication and dissemination rates are the primary factors controlling the speed that the rash spreads, whereas the rate that active macrophages are cleared from the dermis is the principle determinant of rash morphology. In addition, the model supports the clinical observations that antibiotic treatment quickly clears spirochetes from the dermis and that the rash appearance is not indicative of the efficacy of the treatment. The quantitative agreement between our results and clinical data suggest that this model could be used to develop more efficient drug treatments and may form a basis for modeling pathogen-host interactions in other emerging infectious diseases.     

Pinch skin grafting or porcine dermis in venous ulcers: a randomised clinical trial.

Chronic venous ulcers are common, and even with effective compression or elevation large ulcers may take months to heal. Pinch skin grafting may allow healing from epithelial islands throughout the surface area of the ulcer, and a prospective randomised trial was therefore conducted comparing this treatment with porcine dermis dressings. Most patients were treated as outpatients, 25 ulcers being randomised to treatment with pinch skin grafts and 28 to treatment with porcine dermis. Though the groups were well matched, the mean healing rate in the first week was 15 cm2 for pinch skin grafts compared with 3.5 cm2 with porcine dermis (p less than 0.02). By life table analysis 64% of ulcers treated by pinch grafts were healed at six weeks and 74% by 12 weeks compared with 29% and 46% of ulcers, respectively, treated with porcine dermis dressings (chi2 = 4.1; p less than 0.05). All ulcers that failed to heal within 12 weeks included an area posterior to the medial malleolus, where local compression may have been inadequate. Pinch skin grafting improves the rate of healing in large venous ulcers and is a simple technique that may be performed as an outpatient procedure under local anaesthesia.     

Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) III. Pathology

The microscopical pathology of Ichthyophthiriasis was studied in a group of mirror carp infected with measured numbers of parasites under standardized conditions. Primary pathology consisted of inflammatory, proliferative, and degenerative changes in the epidermis and hyperaemia and oedema of the spongiose dermis. This was accompanied by changes in the amount and distribution of pigment in the spongiose dermis. Proliferation of interlamellar epithelial tissue of the gills in response to the parasite resulted in partial or complete filling of the interlamellar spaces. Secondary changes noted in the disease were devacuolization of hepatocytes, leukocytic depletion of the mesonephric kidneys, and leukocytic metaplasia or hyperplasia in the spleen.     

Monocyte Recruitment to the Dermis and Differentiation to Dendritic Cells Increases the Targets for Dengue Virus Replication

Dengue virus (DENV) causes the most prevalent arthropod-borne viral disease in humans. Although Aedes mosquitoes transmit DENV when probing for blood in the skin, no information exists on DENV infection and immune response in the dermis, where the blood vessels are found. DENV suppresses the interferon response, replicates, and causes disease in humans but not wild-type mice. Here, we used mice lacking the interferon-α/β receptor (Ifnar ^–/–), which had normal cell populations in the skin and were susceptible to intradermal DENV infection, to investigate the dynamics of early DENV infection of immune cells in the skin. CD103⁺ classical dendritic cells (cDCs), Ly6C^– CD11b⁺ cDCs, and macrophages in the steady-state dermis were initial targets of DENV infection 12-24 hours post-inoculation but then decreased in frequency. We demonstrated recruitment of adoptively-transferred Ly6C^high monocytes from wild-type and Ifnar ^–/– origin to the DENV-infected dermis and differentiation to Ly6C⁺ CD11b⁺ monocyte-derived DCs (moDCs), which became DENV-infected after 48 hours, and were then the major targets for virus replication. Ly6C^high monocytes that entered the DENV-infected dermis expressed chemokine receptor CCR2, likely mediating recruitment. Further, we show that ∼100-fold more hematopoietic cells in the dermis were DENV-infected compared to Langerhans cells in the epidermis. Overall, these results identify the dermis as the main site of early DENV replication and show that DENV infection in the skin occurs in two waves: initial infection of resident cDCs and macrophages, followed by infection of monocytes and moDCs that are recruited to the dermis. Our study reveals a novel viral strategy of exploiting monocyte recruitment to increase the number of targets for infection at the site of invasion in the skin and highlights the skin as a potential site for therapeutic action or intradermal vaccination.     

Quantitative alterations of hyaluronan and dermatan sulfate in the hairless mouse dorsal skin exposed to chronic UV irradiation.

The quantitative alterations of hyaluronan and dermatan sulfate in the upper dermis (fibrous tissue) and the lower dermis (adipose tissue) of the hairless mouse skin chronically exposed to the UV irradiation as solar-simulating irradiation (lambda(max) 352 nm, UV distribution: 300-310 nm, 0.9%; 310-320 nm, 2.0%; 320-420 nm, 97.1%) were evaluated. Hyaluronan and dermatan sulfate contents in each part of dermis were determined as follows: skin sections on a glass slide prepared by histological technique were processed into the upper dermis and the lower dermis with a small surgical knife, and treated with chondroitinase ABC and ACII in the presence of bacterial collagenase. The resulting unsaturated disaccharides were determined by HPLC method. By applying this method to the UV-irradiated hairless mouse skin, it was found that the chronic UV irradiation increased dermatan sulfate in the upper dermis, whereas an increase of hyaluronan content was not statistically significant. In the lower dermis, on the contrary, both hyaluronan and dermatan sulfate contents remarkably increased as compared with the control mice. Furthermore, the histological study showed the accumulation of the collagen fibers in the lower dermis of the UV-irradiated hairless mouse skin following the disappearance of adipocytes. These findings indicate that the increases of glycosaminoglycan contents in the UV-irradiated skin are related to the accumulation of the extracellular matrix components in the lower dermis.     

Systemic FasL and TRAIL neutralisation reduce leishmaniasis induced skin ulceration

Cutaneous leishmaniasis (CL) is caused by Leishmania infection of dermal macrophages and is associated with chronic inflammation of the skin. L. aethiopica infection displays two clinical manifestations, firstly ulcerative disease, correlated to a relatively low parasite load in the skin, and secondly non-ulcerative disease in which massive parasite infiltration of the dermis occurs in the absence of ulceration of epidermis. Skin ulceration is linked to a vigorous local inflammatory response within the skin towards infected macrophages. Fas ligand (FasL) and Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expressing cells are present in dermis in ulcerative CL and both death ligands cause apoptosis of keratinocytes in the context of Leishmania infection. In the present report we show a differential expression of FasL and TRAIL in ulcerative and non-ulcerative disease caused by L. aethiopica. In vitro experiments confirmed direct FasL- and TRAIL-induced killing of human keratinocytes in the context of Leishmania-induced inflammatory microenvironment. Systemic neutralisation of FasL and TRAIL reduced ulceration in a model of murine Leishmania infection with no effect on parasitic loads or dissemination. Interestingly, FasL neutralisation reduced neutrophil infiltration into the skin during established infection, suggesting an additional proinflammatory role of FasL in addition to direct keratinocyte killing in the context of parasite-induced skin inflammation. FasL signalling resulting in recruitment of activated neutrophils into dermis may lead to destruction of the basal membrane and thus allow direct FasL mediated killing of exposed keratinocytes in vivo. Based on our results we suggest that therapeutic inhibition of FasL and TRAIL could limit skin pathology during CL.     

Structural and functional evaluation of modifications in the composite skin graft: cryopreserved dermis and cultured keratinocytes.

Structural and functional aspects of modifications in the composite skin graft consisting of cultured keratinocytes and cryopreserved dermis were determined. Cryopreserved human cadaveric dermis separated from skin by short and mild trypsinization was compared with dermis obtained by prolonged incubation in medium and with fresh dermis obtained by the same methods. All types of dermis were shown to retain normal ultrastructure and topographic organization, as detected by scanning and transmission electron microscope and immunofluorescence analysis. However, in fresh skin, the layers were more firmly attached, mechanical separation was more difficult, and residual epidermis often remained attached to the dermis. Keratinocytes attached better, began replication earlier, and generally reached higher cell numbers when cultured on trypsinized dermis than on medium-treated dermis. The performance of several modifications in the reconstitution and grafting procedures of the composite skin graft after transplantation to athymic mice was examined. Cultured epidermis combined onto trypsinized or medium-treated whole and meshed dermis, dermis pregrafted and allowed to take before transplanting epidermis on top, and keratinocytes grown into multiple epithelia on top of trypsinized meshed or whole dermis prior to grafting. The best grafting results were obtained with an "instant" reconstituted skin model: multiple epithelia grown in vitro combined immediately before grafting onto meshed trypsinized dermis. The transplantation results of this modification were significantly better than those of all the other modifications, including initial growth of keratinocytes into multiple epithelia on top of trypsinized dermis prior to grafting.     

Regional specificity of anuran larval skin during metamorphosis: dermal specificity in development and histolysis of recombined skin grafts

Summary Skins from back and tail were dissected from tadpoles of Rana japonica prior to resorption of the tail and separated into epidermis and dermis by treatment with neutral protease. Homotypically and heterotypically recombined skins were constructed from the separated epidermis and dermis and transplanted into the tail of the original tadpole. Skin grafts using dermis from tail region degenerated simultaneously with resorption of the tail. However, skin grafts containing dermis from back region survived on the posterior part of the juvenile frog beyond metamorphosis. Furthermore, all epidermis underlaid with dermis from back region formed secretory glands and became flattened epithelia characteristic of adult back skin, regardless of region from which the epidermis came. Even when epidermis isolated from tail skin was cultured inside a back skin graft, the tail epidermis survived forming an epithelial cyst and developed secretory glands. These results suggest that regional specificities of anuran larval skin, i.e., development of back skin and even histolysis of tail skin, are determined by regionally specific dermis. The results also suggest that some of epidermal cells of tail skin are able to differentiate into epithelial cells similar to back skin of the adult under the influence of back dermis.     

Avian scale development. XIII. Epidermal germinative cells are committed to appendage-specific differentiation and respond to patterned cues in the dermis.

The ability of the germinative cell population of scutate scale epidermis to continue to generate cells that undergo their appendage-specific differentiation (beta stratum formation), when associated with foreign dermis, was examined. Tissue recombination experiments were carried out which placed anterior metatarsal epidermis (scutate scale forming region) from normal 15-day chick embryos with either the anterior metatarsal dermis from 15-day scaleless (sc/sc) embryos or the dermis from the metatarsal footpad (reticulate scale forming region) of 15-day normal embryos. Neither of these dermal tissues are able to induce beta stratum formation in the simple ectodermal epithelium of the chorion, however, the footpad dermis develops an appendage-specific pattern during morphogenesis of the reticulate scales, while the sc/sc dermis does not. Morphological and immunohistological criteria were used to assess appendage-specific epidermal differentiation in these recombinants. The results show that the germinative cell population of the 15-day scutate scale epidermis is committed to generating suprabasal cells that follow their appendage-specific pathways of histogenesis and terminal differentiation. Of significance is the observation that the expression of this determined state occurred only when the epidermis differentiated in association with the footpad dermis, not when it was associated with the sc/sc dermis. The consistent positioning of the newly generated beta strata to the apical regions of individual reticulate-like appendages demonstrates that the dermal cues necessary for terminal epidermal differentiation are present in a reticulate scale pattern. The observation that beta stratum formation is completely missing in the determined scutate scale epidermis when associated with the sc/sc dermis adds to our understanding of the sc/sc defect. The present data support the conclusion of earlier studies that the anterior metatarsal dermis from 15-day sc/sc embryos lacks the ability to induce beta stratum formation in a foreign epithelium. In addition, these observations evoke the hypothesis that the sc/sc dermis either lacks the cues (generated during scutate and reticulate scale morphogenesis) necessary for terminal differentiation of the determined scutate scale epidermis or inhibits the generation of a beta stratum.     

Biochemical Changes Observed After PUVA Versus PUVA Plus Methotrexate Therapy in Mycosis Fungoides Using Synchrotron Infrared Microspectroscopy

Mycosis fungoides (MF) is the most common type of cutaneous T cell lymphoma in which the distinction between early stage MF and other inflammatory dermatosis remains difficult. Twenty patients of early stage MF and nine patients with psoriasis and lichen planus were included in this study. Ten MF patients were treated with psoralen plus UVA (PUVA) and the other 10 MF patients were treated with PUVA plus methotrexate (MTX) until complete clinical remission. Synchrotron infrared microspectroscopy (SIRM) found that MF lesions were biochemically different compared to inflammatory diseases. After treating MF with either therapeutic modality, the lymphocytic count decreased significantly in both the epidermis and dermis (P < 0.001) but no biochemical changes were observed in the remaining lymphocytes after treatment, indicating the disease process was slowed by treatment but not eradicated. In conclusion SIRM is a promising method for distinguishing MF from other inflammatory diseases such as psoriasis and lichen planus. A significant reduction in lymphocyte count indicated that PUVA therapy is an effective treatment for early stage MF, and MTX could be reserved for more advanced cases that are not PUVA responsive. However, SIRM evidence of persistent disease suggests that maintenance therapy is recommended after clinical remission.     

Immunocytochemical localization of collagen types I,III, IV,and fibronectin in the human dermis

Summary The distribution of collagen types I, III, IV, and of fibronectin has been studied in the human dermis by light and electron-microscopic immunocytochemistry, using affinity purified primary antibodies and tetramethylrhodamine isothiocyanate-conjugated secondary antibodies. Type I collagen was present in all collagen fibers of both papillary and reticular dermis, but collagen fibrils, which could be resolved as discrete entities, were labeled with different intensity. Type III collagen codistributed with type I in the collagen fibers, besides being concentrated around blood vessels and skin appendages. Coexistence of type I and type III collagens in the collagen fibrils of the whole dermis was confirmed by ultrastructural double-labelling experiments using colloidal immunogold as a probe. Type IV collagen was detected in all basement membranes. Fibronectin was distributed in patches among collagen fibers and was associated with all basement membranes, while a weaker positive reaction was observed in collagen fibers. Ageing caused the thinning of collagen fibers, chiefly in the recticular dermis. The labeling pattern of both type I and III collagens did not change in skin samples from patients of up to 79 years of age, but immunoreactivity for type III collagen increased in comparison to younger skins. A loss of fibronectin, likely related to the decreased morphogenetic activity of tissues, was observed with age.     

Age differences in immunohistochemical localizations of large proteoglycan, PG-M/versican, and small proteoglycan, decorin, in the dermis of rats.

Proteoglycans were localized immunohistochemically in the dermis of Donryu rats, using monoclonal antibodies raised against large proteoglycan (PG-M/versican) and small proteoglycan (decorin). The localizations of these proteoglycans in the dermis were compared between young rats (22-day old) and old ones (24 or 30 months of age), and distinct age differences were observed. In the young dermis, PG-M/versican was observed to be abundant in almost all fibroblastic cells (both cytoplasm and cell processes) whose cellularity was very rich compared with the dermis of old rats. Decorin was only faintly visible in the interstitial fibrous elements of young dermis. In the old dermis, however, decorin was distinctly detected on the fibrous elements, which were diffusely distributed as a fibrous network, and likewise PG-M/versican was visible in only a few fibrous elements which seemed to be the fine processes of fibroblastic cells. In the border layer between epidermis and dermis as well as the basal layer surrounding hair follicles, both large and small proteoglycans could be observed in old dermis. Since decorin, which was abundant in old dermis, has been found to have a growth inhibitory effect, it is conceivable that decorin may be one of the Cell Growth Inhibitory Factors in aging as proposed by Tauchi et al. [17, 18].