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At least 19 recordsLinked to original sources
PubMed1990

Either chick embryo dermis or retinoid-treated mouse dermis can initiate glandular morphogenesis from mammalian epidermal tissue.

Excess retinoids can cause developing mouse vibrissa follicles to be transformed into mucous glands in organ culture. The objective was to test the hypothesis that retinoids act in this system by altering morphogenetic properties of the dermis. After inititation by retinoic acid (RA) in organ culture, glands were shown to develop further in embryonic skin grafted to the chick chorioallantoic membrane (CAM). Recombinants of 12.5 day mouse epidermis with untreated or RA-treated mouse or chick dermis were then grafted to CAM for 7 days. For homospecific recombinants, 13.5 day mouse dermis originated from 11.5 day skin cultured for 2 days, with or without 5.2 microgram/ml RA. For heterospecific recombinants, 12 day dermis came from chick embryos, previously injected with 250 microgram RA. Glands were absent from the homospecific recombinants including untreated mouse dermis, but appeared in 26% of those with RA-treated dermis. Among heterospecific recombinants, 75% of those with RA-treated chick dermis and 29% of those with untreated dermis had glands. Untreated 10-12 day chick skin contained two forms of endogenous vitamin A, retinol (4.5 microgram/g protein) and dehydroretinol (3.7 microgram/g protein), while 13-14 day mouse skin contained only retinol (1.8 microgram/g protein), as shown by high performance liquid chromatography. RA injection increased retinol and dehydroretinol in chick skin, while RA was undetectable. Thus RA can act through mouse dermis to form epithelial glands and through chick dermis to increase the incidence of glands. The glands in recombinants with untreated chick dermis may result from the higher levels of endogenous retinoids in chick skin, compared with mouse skin.

Allantois↗
PubMed1992

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.

Animals↗
PubMed1991

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.

Animals↗
PubMed1989

Region-specific deposition of dermal proteins between dermis and epidermis during induction of chick feather and scale rudiments.

To begin to study the role of particular proteins in inductive tissue interactions, we have used density labelling techniques to determine whether any dermal proteins are found between embryonic chick dermis and epidermis at a stage when the dermis plays an important inductive role in epidermal differentiation. Epidermis will form feathers or scales depending on whether it interacts with dorsal or foot dermis, respectively, and the dermis can still influence epidermal differentiation when direct cell contact between the tissues is blocked by a membrane filter during culturing (Peterson & Grainger, 1985). In transfilter experiments, we detect a subset of dermal proteins within the filter between the tissues. Several of these dermal proteins are deposited in a region-specific manner, that is, they are only found associated with filters from either dorsal or foot dermis. We have previously shown that the expression of some of these proteins is specific to particular regions of dermis and is also associated with the inductive potential of the dermis (Peterson & Grainger, 1986). We detect only 17 dermal proteins which are transferred across the filter in these cultures and found in direct association with epidermis; of these 14 are common to both dorsal and foot dermis, and 3 are deposited in a region-specific manner. Our results lead us to hypothesize a significant function for certain dermal proteins in this inductive interaction either as part of the extracellular matrix or in direct association with epidermis.

Animals↗
PubMed1992

[Experimental study on a skin substitute. Artificial dermis epidermised by human keratinocytes].

In patients with third-degree burns, plastic surgeons must meet emergent requirements for skin coverage. Conventional autografts do not provide enough substance to cover these patients, hence the interest of skin substitutes. The aim of our work is to achieve epidermization of an artificial dermis with a technique of culture of human keratocytes, thus producing in vitro a dermoepidermal skin substitute akin to normal skin, and to implant it in nude mice. Human keratocytes are grown in a definite medium (MCDB 153) on an artificial dermis based on type I and III collagen and glycosaminoglycans, and cross-linked with chitosan. Human keratocytes from thin skin were seeded on the artificial dermis after a last passage in culture fials. Cell density and the number of days in vitro were varied on patches of artificial dermis. After culture, the patches were transferred on nude mice. These were sacrificed on the 7th or 14th day. Cell recolonization of the artificial dermis was then studied, as well as the growth of the epidermis on deep-frozen histologic sections. Primary cultures on an artificial dermis did not show production of a satisfactory epidermis. In some animals grafted with artificial dermis epidermized in a secondary culture, we observed a structure similar to that of normal skin. This work allowed outlining the problems to slove and contemplating the solutions required to develop a total artificial skin.

Animals↗
PubMed1977

Epidermal-dermal tissue interactions between mutant foot skin and normal back skin: a comparison of the inductive capacities of scaleless low line and normal anterior foot dermis.

The inductive capacities of 9- to 16-day anterior foot dermis of scaleless low line and normal embryos were compared by recombining them with a common source of epidermis, i.e., 7-day normal back epidermis. Tissue recombinants were cultured as grafts to the chorioallantoic membrane (CAM). Both normal and scaleless low line dermis of 12 to 13 days of incubation began to lose their ability to elicit feather production in 7-day normal back epidermis. Normal foot dermis began to elicit scale production at 12 to 13 days, whereas scaleless low line anterior foot dermis maintained feather production at a low level. It is inferred that without being associated with scale placode formation, scaleless low line anterior foot dermis does not acquire specific inductive capacities related to the production of an outer scale surface in the overlying epidermis. Feather placodes do not function as surrogates of scale placodes. The difference between normal and scaleless low line anterior foot dermis in terms of specific inductive capacities related to scale production is interpreted as a secondary effect of the action of the scaleless allele in interfering with scale placode formation in the scaleless low line anterior foot epidermis.

Animals↗
PubMed1991

The initial expression and patterned appearance of tenascin in scutate scales is absent from the dermis of the scaleless (sc/sc) chicken.

Morphogenesis of the anterior metatarsal skin (scutate scale region), from 9.5 to 12 days of development, results in the formation of orderly patterned scale ridges. It is after the initial formation of the Definitive Scale Ridge that the characteristic outer and inner epidermal surfaces differentiate. The hard, plate-like beta stratum, with its unique beta keratins, characterizes the epidermis of the outer surface, while the epidermis of the inner surface elaborates an alpha stratum. The anterior metatarsal region of the scaleless mutant does not undergo scale morphogenesis. Therefore, scale ridges do not form nor do the outer and inner epidermal surfaces with their characteristic beta and alpha strata. We have found that the extracellular matrix molecule, tenascin, first appears in the scutate scale dermis at 12 days of development when the scale ridge is established. Tenascin is found in the dermis only under the scale ridge and is not associated with the dermal-epidermal junction. Tenascin is not found in scaleless anterior metatarsal dermis at this time. As outgrowth of the Definitive Scale Ridge takes place, tenascin distribution correlates closely with the formation of the outer epidermal surface of each scale ridge. By 16 days of development tenascin is also found in close association with the dermal-epidermal junction. Tenascin does not appear in scaleless anterior metatarsal dermis until 16 days of development and then it is randomly and sparsely distributed at the dermal-epidermal junction. Tenascin's initial appearance and pattern of distribution in the scutate scale dermis and its abnormal expression in the scaleless dermis suggest that morphogenesis plays a significant role in regulation of its expression.

Animals↗
PubMed1991

The domed dermis-fat graft orbital implant.

Dermis-fat grafts have been widely used in the reconstruction of the anophthalmic socket, both primarily after enucleation and secondarily after extrusion or migration of an existing implant. The dermis-fat graft is an effective means of replacing orbital volume and affording motility of the ocular prosthesis with both low morbidity and a satisfactory cosmetic result. We present a modification to the dermis-fat graft technique. Our modification creates a domed shape to the anterior surface of the graft that simulates the curvature of the eye. The dome-shaped graft creates deeper fornices than a standard flat-surfaced dermis-fat graft. It also allows better contact between the prosthesis and the dermis as the graft moves. The prosthesis can be thinner centrally and lighter than a prosthesis fabricated for a socket with a standard dermis-fat graft or spherical implant. This results in better motility of the prosthesis while also replacing orbital volume. There is no additional morbidity associated with this technique. We have used this procedure successfully in 18 patients; 10 were primary grafts and eight secondary grafts. Motility of the prosthesis was satisfactory in all cases. There was no abnormal graft shrinkage. All grafts maintained their domed shape. Follow-up ranged from 6 to 21 months.

Adipose Tissue↗
PubMed1991

In vitro reconstitution of skin: fibroblasts facilitate keratinocyte growth and differentiation on acellular reticular dermis.

Extensive full-thickness burns require replacement of both epidermis and dermis. We have described a method in which allogeneic dermis from engrafted cryopreserved cadaver skin was combined with cultured autologous keratinocytes. In the present study we combined human keratinocytes and fibroblasts, and acellular human dermis in vitro and transplanted this "reconstituted skin" into athymic mice. Both human papillary dermis in which the basement membrane zone has been retained and human reticular dermis that has been repopulated with human dermal fibroblasts are good substrates for keratinocyte attachment, stratification, growth, and differentiation. Both of these dermal preparations can be lyophilized and stored at room temperature without losing their ability to support keratinocyte growth. In contrast, human papillary dermis that has been treated with trypsin lacks laminin and collagen type IV in the BMZ and supports keratinocyte attachment and differentiation less well.

Animals↗
PubMed1975

In vitro uptake of calcium by dermis of patients with pseudoxanthoma elasticum.

The calcification of dermal elastic fibers is a characteristic feature of affected skin from patients with pseudoxanthoma elasticum (PXE). Punch biopsies of normal skin and of affected and unaffected skin from patients with PXE were obtained to study dermal calcification in vitro. Before incubation, the calcium, magnesium, and phosphorus content of normal and PXE unaffected dermis were similar and that of PXE affected dermis was significantly higher. Dermal samples were incubated for 2 and 4 days at 37 degrees C. in a calcium phosphate buffer and the Ca and P content were measured. After 4 days of incubation, both PXE affected and unaffected dermis took up significantly more Ca and PO4 than normal dermis. Thus in vitro uptake study could clearly distinguish between normal and PXE dermis. PXE is a disease of variable expression and mild or subclinical forms are difficult to diagnose. Dermal biopsies from clinicallu normal relatives of patients with PXE were obtained and the in vitro uptake of Ca and PO4 was measured. The results show that several of these individuals had elevated uptakes of Ca and PO4 similar to the unaffected dermis of the PXE patient. The results suggest that this test may be used as a diagnostic aid in the detection of individuals with mild forms of PXE and may be a genetic marker for PXE.

Calcinosis↗
PubMed1992

Immunohistochemical study of basement membrane reconstruction by an epidermis-dermis recombination experiment using cultured chick embryonic skin: induction of tenascin.

The production of extracellular matrix components such as laminin, Type IV collagen, fibronectin, and tenascin during the formation of basement membrane in cultured epidermis-dermis recombinant skin of 13-day-old chick embryo was analyzed immunohistochemically. The epidermis and dermis were separated from each other by treatment with EDTA and/or dispase. The basal lamina of the basement membrane was thus removed from both epidermis and dermis. The isolated epidermis was overlaid onto the isolated dermis, i.e., recombined, and then cultured for 1-7 days in a chemically defined medium (BGJb) on a Millipore filter. Immunofluorescence labeling was used for light microscopy and HRP or colloidal gold labeling for electron microscopy. In specimens from 2-day cultures, positive sites of anti-laminin and anti-fibronectin reaction were observed light microscopically as patches which, at the electron microscopic level, corresponded to fragments of the basal lamina located immediately beneath and in the vicinity of the attachment plaques of the hemidesmosomes. The staining pattern became continuous 7 days after recombination. Fluorescence labeling of laminin and fibronectin appeared somewhat earlier than that of Type IV collagen and tenascin. All of the four components were found localized primarily in the basal lamina. Furthermore, fibronectin and tenascin were also distributed in the extracellular matrix of the dermis. The expression of tenascin, which does not exist in the basement membrane of 13-day-old intact embryonic skin, was induced in vitro. These results suggest that hemidesmosomes may play an important role in the reconstruction of the basement membrane and that various components of the basement membrane appeared at different times during the reconstruction.

Animals↗
PubMed1990

Cellular elements of the dermis and collagen remodelling during larval life of anurans.

The differentiation of the collagenous dermis has been followed by electron microscopy in larvae of three anuran species. Events can be divided into five phases, depending on the organization of the cellular elements. Initial secretion of collagen appears to be from the epidermis but fibroblasts are present from early stages. Apart from secretion, there is phagocytosis of fibrils by fibroblasts, seen most frequently when the operculum is formed and at metamorphosis. In most larval stages, the dermis consists of regular plies of collagen fibrils, penetrated by processes from underlying fibroblasts and crossed by nerves, with a cellular layer defining the deep face. In Rana, these cells contain enormous vacuoles and have been called "compartmented cells", but the vacuoles are absent in Bufo and Xenopus. Just before metamorphosis, fibroblasts and chromatophores migrate into the dermis, and establish a stratum laxum. A few plies of larval collagen fibrils are left under the epidermis, the bulk of the larval dermis becomes the stratum compactum. During larval life, the hypodermis contains chromatophores, blood capillaries and wandering leucocytes. The dermis gains a blood circulation only at metamorphosis, when subdermal lymph sacs and vertical smooth muscles are established.

Animals↗
PubMed1989

Biochemical, morphological and stereological study of the dermis in three members of a large family with type IV Ehlers-Danlos syndrome.

Biochemical, morphological and stereological studies were carried out on dermal biopsies obtained from three members of a large family with a positive clinical history of type IV Ehlers-Danlos syndrome. Ultrastructural analysis showed that fibroblasts from two affected individuals presented abnormally dilated rough endoplasmic reticulum cisternae engorged by microfilamentous material. When cultured, fibroblasts from two affected individuals synthesized and secreted normal amounts of type I procollagen, but only a very low percentage of type III procollagen was secreted. Cellular retention of type III procollagen was confirmed by immunofluorescence. Also the secretion of fibronectin appeared delayed. Stereological analysis carried out on semithin sections of dermis by the point counting method showed that the relative volume of collagen fibers was decreased in the reticular dermis and the relative volume of elastin fibers was increased mainly in the upper layer of reticular dermis, in comparison to normal controls (P less than 0.01). Collagen fiber sizes were significantly (P less than 0.01) reduced in all dermis layers. No alterations were seen in the dermis and in cultured fibroblasts from the clinically normal individual.

Adolescent↗
PubMed1992

Changes in the ventral dermis and development of iridophores in the anadromous sea lamprey, Petromyzon marinus, during metamorphosis: an ultrastructural study.

The ultrastructural changes that take place in the ventral dermis along with the development of iridophores were examined in the anadromous sea lamprey, Petromyzon marinus, during metamorphosis. There is a disruption of all components of the ventral dermis and a reformation that results in a structure very similar to that prior to metamorphosis. Although not a dermal component, a layer of iridophores develops directly beneath the dermis during late metamorphosis. The dermal endothelium is lost by mid metamorphosis (stage 4) and the highly organized collagenous lamellae making up the bulk of the dermis become disrupted by the migration of fibroblasts into the region. Many of these fibroblasts are involved in the degradation of the lamellae. By stage 5 of metamorphosis some fibroblasts become highly active collagen synthesizing cuboidal shaped cells that align to form a layer above the reformed dermal endothelium. New lamellae are formed by these cuboidal cells which then divide and migrate into the lamellae where they assume the characteristic attenuated appearance of fibroblasts in the adult dermal lamellae region. Iridophores first appear during stage 5 directly beneath the dermal endothelium. Reflecting platelets develop from double membraned vesicles associated with the Golgi apparatus. By late metamorphosis, stacks of trapezoidal shaped platelets fill the cytoplasm of the iridophores. The significance of the changes in the dermis during metamorphosis are discussed. This work is part of a continuing series of studies on the connective tissues in the anadromous sea lamprey.

Animals↗
PubMed1991

Reconstruction of basement membrane in recombinants of epidermis and dermis of chick embryonic skin in vitro: an electron microscopic study.

The tarsometatarsal skin from 13-day-old chick embryos was treated with EDTA and/or Dispase to separate it into epidermis and dermis, and the basal lamina was removed. The isolated epidermis and dermis were then recombined and cultured on Millipore filters in a chemically defined medium (BGJb). Beginning at 3-4 days after recombination, short fragments of new basal lamina and subbasal dense plaque were formed along the epidermal basal cell outer surface immediately subjacent to hemidesmosomes. After 6-8 days of culture, fragments of the basal lamina started to fuse together and the lamina became progressively continuous. At the same time, anchoring fibrils were formed to attach to the basal lamina. The hemidesmosome formation preceded the basement membrane formation. When normal embryonic epidermis was recombined with retinol-pretreated dermis and cultured for 7 days in BGJb, short fragments of the basal lamina, the subbasal dense plaque, and anchoring fibrils were formed, but the basement membrane remained discontinuous with many interruptions in the interspace between hemidesmosomes. These results demonstrate that pretreatment of dermis with retinol causes the changes noted in the basement membrane.

Animals↗
PubMed1992

Immunocytochemical localization of collagen types I, III, IV, and fibronectin in the human dermis. Modifications with ageing.

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 reticular 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.

Adolescent↗
PubMed1991

Proliferating cells in psoriatic dermis are comprised primarily of T cells, endothelial cells, and factor XIIIa+ perivascular dendritic cells.

Determination of the cell types proliferating in the dermis of patients with psoriasis should identify those cells experiencing activation or responding to growth factors in the psoriatic dermal milieu. Toward that end, sections of formalin-fixed biopsies obtained from 3H-deoxyuridine (3H-dU)-injected skin of eight psoriatic patients were immunostained, followed by autoradiography. Proliferating dermal cells exhibit silver grains from tritium emissions. The identity of the proliferating cells could then be determined by simultaneous visualization with antibodies specific for various cell types. UCHL1+ (CD45RO+) T cells (recall antigen-reactive helper T-cell subset) constituted 36.6 +/- 3.1% (mean +/- SEM, n = 6) of the proliferating dermal cells in involved skin, whereas Leu 18+ (CD45RA+) T cells (recall antigen naive T-cell subsets) comprised only 8.7 +/- 1.5% (n = 6). The Factor XIIIa+ dermal perivascular dendritic cell subset (24.9 +/- 1.5% of proliferating dermal cells, n = 6) and Factor VIII+ endothelial cells (23.0 +/- 2.3%, n = 6) represented the two other major proliferating populations in lesional psoriatic dermis. Differentiated tissue macrophages, identified by phase microscopy as melanophages or by immunostaining with antibodies to Leu M1 (CD15) or myeloid histiocyte antigen, comprised less than 5% of the proliferating population in either skin type. In addition to calculating the relative proportions of these cells to each other as percent, we also determined the density of cells, in cells/mm2 of tissue. The density of proliferating cells within these populations was increased in involved versus uninvolved skin: UCHL1+, 9.0 +/- 1.7 cells/mm2 versus 1.8 +/- 0.6 cells/mm2, p less than 0.01; Factor XIIIa+, 6.0 +/- 0.7 cells/mm2 versus 1.5 +/- 0.5 cells/mm2, p less than 0.01; Factor VIII+, 5.5 +/- 1.4 cells/mm2 versus 0.0 cells/mm2, p less than 0.05. The presence of preferential active proliferation of a T-cell subset in lesional dermis suggests that activating signals specific for this subset are contained within the psoriatic dermis in vivo. The activation of recall antigen-reactive T cells may be a driving force behind the dendritic cell and endothelial cell proliferation. Alternatively, the selective proliferation and expansion of these two constitutive cell types (Factor XIIIa+ and Factor VIII+) may result in signals that promote activation of UCHL1+ (CD45RO+) T cells.

Cell Division↗