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PubMed2001

Development of an artificial dermis preparation capable of silver sulfadiazine release.

This article describes the antibacterial effects of an artificial dermis impregnated with silver sulfadiazine (Ag-SD) in vitro as well as in vivo. In the in vitro test, silver release from the artificial dermis impregnated with Ag-SD, by immersion in collagenase solution was controlled by the degradation of the collagen sponge. The artificial dermis impregnated with 3% or higher doses of Ag-SD completely suppressed the growth of Pseudomonas aeruginosa (Ps.) or Staphylococcus aureus (St.). The cytotoxicity test revealed that impregnation of 5% or higher doses of Ag-SD suppressed the growth of fibroblasts. However, when the artificial dermis impregnated with Ag-SD was implanted into full-thickness skin defects on the backs of guinea pigs, no tissue damage was histologically observed around the implanted site of the dermis. In the in vivo test, the artificial dermis impregnated with 10% Ag-SD, which was grafted on experimentally contaminated wounds in the backs of guinea pigs, macroscopically suppressed degradation of the collagen sponge, and significantly reduced the growth of both Ps. and St., compared with artificial dermis without Ag-SD. We conclude that collagen sponge impregnated with Ag-SD is a promising artificial dermis applicable to treat contaminated wounds.

Animals↗

PubMed2002

Mucosal reconstruction using an artificial dermis after KTP laser surgery.

OBJECTIVE: The aim of the present study is to assess the clinical effectiveness of the artificial dermis. BACKGROUND DATA: We have previously observed prolonged postoperative pain and bleeding in patients receiving potassium titanyl phosphate (KTP) laser surgery for oral mucosal diseases. MATERIALS AND METHODS: The artificial dermis was placed on the wound and fixed to the surrounding oral mucosa by silk suturing. The silicon sheet of the artificial dermis and the sutures were removed on the seventh postoperative day. Postoperative bleeding from the oral mucosa, duration of postoperative pain, and the period required for healing were all assessed clinically. The results were compared to those in a group of similar cases which were treated without the artificial dermis. In this retrospective review, we considered 20 cases of tongue lesion treated by KTP laser (10 leukoplakias, nine squamous cell carcinomas, and one metastatic renal cell carcinoma to the tongue), nine of which were followed by application of an artificial dermis to prevent postoperative pain and bleeding, and 11 of which were not. RESULTS: No postoperative bleeding was observed in the group of cases treated with an artificial dermis, although it was observed in 45.5% in the group of cases treated without an artificial dermis. There was a statistical difference between these two groups (p < 0.03). CONCLUSION: It was concluded that use of artificial dermis prevented postoperative bleeding.

Aged↗

PubMedDate not supplied

Evaluation of acellular human dermis as a dermal analog in a composite skin graft.

This study evaluated the structure and function of a dermal substitute composed of de-epidermalized, acellular human dermis, and tested its performance as part of a composite skin graft with cultured human keratinocytes. The acellular dermis retained much of the complex structure of native dermis, as demonstrated by immunostaining for collagen Types IV and VII. Collagen Types IV and VII were found on the papillary surface, and collagen Type IV was found at sites throughout the acellular dermis. To further demonstrate the functionality of the acellular dermis material, we seeded the papillary surface with cultured keratinocytes. In response to the architecture of the dermal papillae, the keratinocytes formed a three-dimensional epidermal structure that was several cell layers thick, and recreated the original skin rete ridges at the interface with the dermis. When these composite grafts were transplanted to athymic mice, host fibrovascular cells repopulated the acellular dermis. Some vessels grew into the acellular dermis along the original pathways of the human blood vessels, as demonstrated by co-localization of human and mouse collagen Type IV. The skin that developed from these grafts repigmented completely via passenger melanocytes from the keratinocyte cultures, was durable, and remained stable for more than 5 months.

Animals↗

PubMed1986

Dermis-derived 15-hydroxy-eicosatetraenoic acid inhibits epidermal 12-lipoxygenase activity.

The purpose of the present study was to analyze the metabolism of arachidonic acid (AA) in normal human dermis. After incubating homogenized dermis with exogenous AA, the extracted lipids were isolated by reversed-phase high-performance liquid chromatography. Each chromatographic peak was characterized by its UV absorption spectrum and identified by its coelution with the appropriate authentic standard and by radioimmunoassay of its eluate fraction. Identified compounds were quantitated by integrated optical density. Homogenized human dermis transformed AA into both cyclooxygenase and lipoxygenase products, but predominantly 15-hydroxy-eicosatetraenoic acid (15-HETE). Cultured fibroblasts from normal human dermis also mainly metabolized AA into 15-HETE. To determine whether dermis-derived 15-HETE might modify the AA metabolism of epidermis, normal human epidermis was incubated with dermis. Increasing amounts of dermis resulted in an increasing inhibition of epidermal 12-HETE formation. Similarly, 15-HETE alone induced a dose-dependent decrease of epidermal 12-HETE formation, while the formation of prostaglandin E2 was unchanged. Since 12-HETE possess the ability to elicit skin inflammation and to stimulate epidermal DNA synthesis, 15-HETE formation may be a way whereby dermis regulates important epidermal activities.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1993

Antioxidant defense mechanisms in murine epidermis and dermis and their responses to ultraviolet light.

A comprehensive comparison of antioxidant defenses in the dermis and epidermis and their response to exposure to ultraviolet (UV) irradiation has not previously been attempted. In this study, enzymic and non-enzymic antioxidants in epidermis and dermis of hairless mice were compared. Enzyme activities are presented both as units/gram of skin and units/milligram of protein; arguments are presented for the superiority of skin wet weight as a reference base. Catalase, glutathione peroxidase, and glutathione reductase (units/gram of skin) were higher in epidermis than dermis by 49%, 86%, and 74%, respectively. Superoxide dismutase did not follow this pattern. Lipophilic antioxidants (alpha-tocopherol, ubiquinol 9, and ubiquinone 9) and hydrophilic antioxidants (ascorbic acid, dehydroascorbic acid, and glutathione) were 24-95% higher in epidermis than in dermis. In contrast, oxidized glutathione was 60% lower in epidermis than in dermis. Mice were irradiated with solar light to examine the response of these cutaneous layers to UV irradiation. After irradiation with 25 J/cm2 (UVA + UVB, from a solar simulator), 10 times the minimum erythemal dose, epidermal and dermal catalase and superoxide dismutase activities were greatly decreased. alpha-Tocopherol, ubiquinol 9, ubiquinone 9, ascorbic acid, dehydroascorbic acid, and reduced glutathione decreased in both epidermis and dermis by 26-93%. Oxidized glutathione showed a slight, non-significant increase. Because the reduction in total ascorbate and catalase was much more severe in epidermis than dermis, it can be concluded that UV light is more damaging to the antioxidant defenses in the epidermis than in the dermis.

Animals↗

PubMed2001

Analysis of the vascularity of an atelocollagen sponge substitute dermis in the human.

Atelocollagen sponge had been developed as a new beneficial dermal substitute. However, histologic studies of the vascularity of an atelocollagen sponge substitute dermis in humans are very rare. The purpose of this study was to determine the distribution of blood vessels in an artificial dermis made of atelocollagen affixed to human tissue. The artificial dermis was used in 21 cases and at 23 sites, and biopsies were performed. The samples were stained with anti-human blood type A, B, and H monoclonal antibodies. Angiogenesis in the upper layer of the artificial dermis was recognizable within 14 days after affixing the artificial dermis. We concluded that a skin graft taken 14 days after affixing the artificial dermis would be successful, even though the granulation tissue formation might not be completed and the color would most likely remain white. The lower layer of the angiogenesis spread in a horizontal direction like an expanded network of blood vessels, while the middle and upper layers of angiogenesis spread perpendicularly to form upward growth when two cases were examined in various spots. The data suggested that the sponge construction of artificial dermis not only became a scaffold for the invasion of collagen, but it also facilitated construction of near normal dermis with regard to the construction of blood vessels.

Adult↗

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↗

PubMed1995

Behavior of propylene glycol (PG) in dermis after treatment of rat intact skin surface with fatty acids, fatty amines or azone dissolved in PG.

Rat abdominal intact skin was treated with fatty acids, fatty amines, or Azone which were dissolved in propylene glycol (PG) and PG appearing in the rat dermis was studied. Analysis was done by Fourier transform infrared/attenuated total reflection (FT-IR/ATR) spectroscopy. The appearance of PG with time seemed to be in three phases when the skin sample was treated with a skin penetration enhancer such as oleic acid: (1) in the first stage, PG penetrated the skin barrier which was not substantially altered, and gradually appeared in the dermis; (2) in the second stage, it rapidly distributed in/throughout the dermis, and this rapid distribution was probably due to the alteration of the dermal structure: the penetration enhancing effect of the enhancer was thought to reach maximal; and (3) in the third stage, PG was saturated in the dermis. The value of T(max alteration), at which the alteration of the dermal structures is completed, showed that the action of both oleic acid and oleylamine were more rapid than other enhancers. Both the value of PG peak area(max) at the third stage which reflects the distribution volume of PG in the dermis and the value of T(sat) at which PG is saturated in the dermis were calculated, and the results suggested that both the distribution volume of PG in the dermis and the time of the saturation varied depending on the enhancer. In conclusion, our present work indicated the importance and necessity of evaluating the rate and extent of appearance of a drug in the dermis to characterize an enhancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Amines↗

PubMed2004

Parasympathetic nerve fibers invade the upper dermis following sensory denervation of the rat lower lip skin.

The sympathetic division of the autonomic nervous system is known to play a role in the genesis of neuropathic pain. In the skin of the rat lower lip (hairy skin), sympathetic and parasympathetic fibers normally innervate the same blood vessels in the lower dermis but do not occur in the upper dermis. However, we have shown that sympathetic fiber migration into the upper dermis occurs following mental nerve lesions (Ruocco et al. [2000] J. Comp. Neurol. 422:287-296). As sensory denervation has a dramatic effect on sympathetic fiber innervation patterns in the rat lower lip skin, we decided to investigate the possible changes in the other autonomic fiber type in the skin-the parasympathetic fiber. Sensory denervation of the rat lower lip was achieved by bilateral transection of the mental nerve, and animals were allowed to recover for 1-8 weeks. Lower lip tissue was processed for double-labeling light microscopic immunocytochemistry (ICC), using antibodies against substance P (SP), which labels a subpopulation of peptidergic sensory fibers, and against the vesicular acetycholine transporter (VAChT), as a marker for parasympathetic fibers. In sham-operated rats, SP-immunoreactive (IR) sensory fibers were found in the epidermis and upper and lower dermal regions, whereas VAChT-IR fibers were confined to the lower dermis. Mental nerve lesions induced the gradual disappearance of SP-IR fibers from all skin layers accompanied by the progressive migration of VAChT-IR fibers into the upper dermis. Cholinergic fiber migration was evident by the second week post surgery, and the ectopic innervation of the upper dermis by these fibers persisted even at the last time point studied (8 weeks) when SP-IR fibers have completely regrown. VAChT-IR fibers were observed in the upper dermis, well above the opening of the sebaceous glands into the hair follicles. These results show that considerable changes occur in the innervation patterns of parasympathetic fibers following mental nerve lesions.

Animals↗

PubMed2001

High-frequency ultrasonic attenuation and backscatter coefficients of in vivo normal human dermis and subcutaneous fat.

In vivo attenuation and backscatter coefficients of normal human forearm dermis and subcutaneous fat were determined in the ranges 14 to 50 MHz and 14 to 34 MHz, respectively. Data were collected using three different transducers to ensure that results were independent of the measurement system. Attenuation coefficient was obtained by computing spectral slopes vs. depth, with the transducers axially translated to minimize diffraction effects. Backscatter coefficient was obtained by compensating recorded backscatter spectra for system-dependent effects and, additionally, for one transducer using the reference phantom technique. Good agreement was seen between the computed attenuation and backscatter results from the different transducers/methods. The attenuation coefficient of the forearm dermis was well described by a linear dependence with a slope that ranged between 0.08 to 0.39 (median = 0.21) dB mm(-1) MHz(-1). The backscatter coefficient of the dermis was generally in the range 10(-3) to 10(-1) Sr(-1) mm(-1) and showed an increasing trend with frequency. No significant differences in attenuation coefficient slope between the forearm dermis and fat were noted. Within the range of 14 to 34 MHz, the ratio of integrated (average) backscatter of dermis to that of fat ranged from 1.03 to 87.1 (median = 6.45), indicating significantly higher backscatter for dermis than for fat. Data were also recorded at the fingertip where the attenuation coefficient slope of the dermis was seen to be higher than that at the forearm.

Adipose Tissue↗

PubMed1999

Cultured autologous keratinocytes on a cell-free dermis in the treatment of full-thickness wounds.

The purpose of this study was to establish a method for transplantation of autologous keratinocytes on an allogenic cell-free dermis. From four healthy volunteers two full thickness skin grafts, 1 x 1 cm, were taken. The epidermis was separated from the dermis enzymatically and the cells of the dermal part were removed by incubation in Triton X-100. Keratinocytes were seeded on a cell-free dermis and the combined graft transplanted back to one of the wounds of the donor of the keratinocytes. The other wound was covered with cell-free dermis without keratinocytes. After 2, 3, 4 and 6 weeks, respectively, the grafted wounds were removed from the subjects and investigated histologically and immunohistochemically regarding re-epithelialisation, fibroblast ingrowth and angiogenesis. The wounds covered with cell-free dermis and keratinocytes showed a complete epidermal coverage 2 weeks after transplantation, in contrast to the wounds covered with un-seeded dermis which only showed epidermal coverage at the wound edges. There was also a marked difference concerning fibroblast ingrowth and angiogenesis. In this study we have shown that autologous keratinocytes can be seeded on a cell-free dermis and transplanted as a kerato-dermal graft which stimulate re-epithelialisation as well as fibroblast ingrowth and angiogenesis in the wound.

Adult↗

PubMed2006

Model for human skin reconstructed in vitro composed of associated dermis and epidermis.

CONTEXT AND OBJECTIVE: The technique of obtaining human skin with dermis and epidermis reconstructed from cells isolated from patients can enable autologous skin grafting on patients with few donor sites. It also enables in vitro trials on chemicals and drugs. The objective of this work was to demonstrate a method for obtaining human skin composed of associated dermis and epidermis, reconstructed in vitro. DESIGN AND SETTING: Experimental laboratory study, in the Skin Cell Culture Laboratory of Faculdade de Ciências Médicas, Universidade Estadual de Campinas. METHODS: Cells from human fibroblast cultures are injected into bovine collagen type I matrix and kept immersed in specific culturing medium for fibroblasts. This enables human dermis reconstruction in vitro. On this, by culturing human keratinocytes and melanocytes, differentiated epidermis is formed, leading to the creation of human skin composed of associated dermis and epidermis, reconstructed in vitro. RESULTS: We showed that human skin composed of associated dermis and epidermis can be successfully reconstructed in vitro. It is histologically formed in the same way as human skin in vivo. Collagen tissue can be identified in the dermis, with cells and extracellular matrix organized in parallel to multilayer epidermis. CONCLUSIONS: It is possible to obtain completely differentiated human skin composed of associated dermis and epidermis, reconstructed in vitro, from injection of human fibroblasts into bovine collagen type I matrix and culturing of human keratinocytes and melanocytes on this matrix.

Animals↗

PubMed2004

In vivo assessment of iron and ascorbic acid in psoriatic dermis.

Reactive oxygen species play an important role in inflammatory skin diseases such as psoriasis. Reactive oxygen species synthesis is catalysed by iron and some species are scavenged by ascorbic acid. The aim of this work was to assess iron and ascorbic acid in uninvolved and involved psoriatic dermis and to compare the corresponding concentrations in the dermis of healthy subjects. Microdialysis associated with atomic absorption spectrometry and gas chromatography-mass spectrometry was used to assess iron and ascorbic acid, respectively. Seven psoriatic patients and five healthy volunteers were studied. Iron concentrations in the involved (57.1 +/- 19.3 microg/l) and uninvolved (49.7 +/- 27.1 microgl/l) psoriatic dermis were higher than the corresponding value determined in the dermis of healthy subjects (21.8 +/- 2.4 microg/l) (p<0.05). Ascorbic acid in involved (47.3 +/- 8.2 microg/ml) and uninvolved (42.0 +/- 14.0 microg/ml) psoriatic dermis was statistically lower than that found in healthy dermis (176.8 +/- 29.0 microg/ml) (p<0.05). These results demonstrate that psoriatic patients exhibit high iron and low ascorbic acid concentrations in the dermis, but there were no significant differences between involved and uninvolved skin.

Adult↗

PubMed1988

Artificial dermis for major burns. A multi-center randomized clinical trial.

This communication presents an 11-center prospective randomized trial using the artificial dermis invented by Burke and Yannas. Patients with life-threatening burns who underwent primary excision and grafting within 7 days of injury had comparable sites randomized to receive either the artificial dermis (study site) or the investigator's usual skin grafting material (control site). Control materials were autograft, allograft, xenograft, or a synthetic dressing. Epidermal grafts were applied to the study site during a second operation, and surviving patients were followed for 1 year after grafting. One hundred thirty-nine sites on 106 patients were studied. Mean burn size was 46.5 +/- 15% mean total body surface (TBSA). Overall mortality was 13%, and mean hospital stay was 68 +/- 45 days. Median artificial dermis take was 80% compared with 95% for all comparative sites, but the take was equivalent to that of all nonautograft control materials. Results with the artificial dermis improved slightly as the investigators became more familiar with the material. Donor site thickness for the study site averaged .006'' +/- .002'' compared to .013'' +/- .018'' for control (p less than .0001) and the epidermal donor site healed an average of 4 days sooner (10 +/- 6 vs. 14 +/- 8 days) (p less than .0001). As the wounds matured during the first year, both patients and surgeons felt that both sites became more comparable in appearance and function. At the completion of the study, there was less hypertrophic scarring of the artificial dermis, and more patients preferred the artificial dermis to the control graft. Artificial dermis with an epidermal graft provides a permanent cover that is at least as satisfactory as currently available skin grafting techniques, and uses donor grafts that are thinner and donor sites that heal faster.

Adolescent↗

PubMed2003

Graft contraction: a comparison of acellular dermis versus hard palate mucosa in lower eyelid surgery.

PURPOSE: To compare graft contraction rates of acellular dermis versus hard palate mucosa when used as free spacer grafts in lower eyelid surgery and to provide clinical outcome data. METHODS: A prospective, nonrandomized clinical trial involving the placement of 19 spacer grafts in the lower eyelids of 14 patients was performed. Indications for spacer graft placement included lower eyelid retraction and mildly contracted socket. Patients with lower eyelid retraction also underwent an endoscopic subperiosteal midface lift. For all procedures, the height of each graft was measured during and after surgery. The amount of contraction was measured for each graft, and a mean was calculated for each spacer material. The clinical success was evaluated for all procedures, based on improvement of the functional concern being addressed. RESULTS: The mean graft contraction rate was 57% for the acellular dermis and 16% for the hard palate mucosal grafts (P <0.005). Of the 7 procedures using acellular dermis for lower eyelid retraction, 6 were considered a success, and 1 was considered a partial success. Of the 6 procedures using hard palate for lower eyelid retraction, 5 were considered a success, and 1 was considered a failure unrelated to the graft. Of the 5 procedures with acellular dermis used for mildly contracted socket, 2 were considered a success, 2 were considered a partial success, and 1 was considered a failure because of graft contraction. The one case using hard palate for mildly contracted socket was considered a success. CONCLUSIONS: Acellular dermis contracts significantly more than hard palate mucosa when used as a lower eyelid spacer graft. Acellular dermis and hard palate mucosa were both associated with a high rate of clinical success in all categories except for patients with a mildly contracted socket who received acellular dermis; more than 60% of these patients (n=5) had only partial success or failure caused by graft contraction.

Adult↗

PubMed1999

Cell-derived stiffening and plasticizing factors in sea cucumber (Cucumaria frondosa) dermis

The stiffness of holothurian dermis can be altered experimentally in vitro by changing the concentration of extracellular Ca(2+). Previous experiments with Cucumaria frondosa have established that these Ca(2+) effects are due to Ca(2+)-dependent cellular processes rather than to direct effects of Ca(2+) on the extracellular matrix. The present report describes two protein factors that are released from cells of C. frondosa dermis by membrane lysis and that directly alter the stiffness of the extracellular matrix. One factor, isolated from the inner dermis, increased tissue stiffness in the absence of Ca(2+). The second factor, from the outer dermis, decreased tissue stiffness in the presence of normal Ca(2+) levels. The relative abundance of these two factors in the inner and outer dermis suggests the possibility that the cells that control tissue stiffness are spatially segregated. Both factors were partially purified under non-denaturing conditions by anion-exchange and gel-filtration chromatography. The partially purified protein preparations retained biological activity. These results suggest that the stiffness of sea cucumber dermis is regulated by cell-mediated secretion of either the stiffening or plasticizing protein and that alterations in dermis stiffness brought about by manipulation of Ca(2+) levels are mediated by effects on secretion of one or both of these proteins.

Journal Article↗

PubMedDate not supplied

Acellular dermis for facial soft tissue augmentation: preliminary report.

OBJECTIVE: To evaluate the efficacy of acellular dermis as a viable alternative for soft tissue augmentation in facial reconstruction. DESIGN: A prospective, nonrandomized observational study consisting of 10 patients who underwent soft tissue augmentation with acellular dermis. SETTING: A tertiary care university medical center in an urban setting. PATIENTS: Ten patients who had undergone soft tissue augmentation using acellular dermis participated in this study. Postimplantation follow-up was 17 to 36 months. INTERVENTION: The amount and location for placement of the acellular dermis was left to the discretion of the surgeon. All implants were placed in the subdermal tissues. MAIN OUTCOME MEASURES: The adequacy of acellular dermis for soft tissue augmentation was assessed by subjective evaluation of implant volume persistence, postoperative complications, and the restoration of normal contour. RESULTS: Of 10 patients who underwent implantation, 9 had no complications and 1 had a recurrent sterile abscess or mucocele at the implantation site. A 22-month postimplantation tissue sampling of acellular dermis in a patient with recurrent tumor revealed approximately 80% to 85% volume persistence. CONCLUSION: Preliminary experience with acellular dermis indicates that it shows promise in soft tissue augmentation.

Adult↗

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↗