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PubMed2006

A comparison of human and porcine acellularized dermis: interactions with human fibroblasts in vitro.

BACKGROUND: Dermal substitutes derived from xenograft materials require elaborate processing at a considerable cost. Acellularized porcine dermis is a readily available material associated with minimal immunogenicity. The objective of this study was to evaluate acellularized pig dermis as a scaffold for human fibroblasts. METHODS: In vitro methods were used to evaluate fibroblast adherence, proliferation, and migration on pig acellularized dermal matrix. Acellular human dermis was used as a control. RESULTS: Pig acellularized dermal matrix was found to be inferior to human acellularized dermal matrix as a scaffold for human fibroblasts. Significantly more samples of human acellularized dermal matrix (83 percent, n = 24; p < 0.05) demonstrated fibroblast infiltration below the cell-seeded surface than pig acellularized dermal matrix (31 percent, n = 49). Significantly more (p < 0.05) fibroblasts infiltrated below the surface of human acellularized dermal matrix (mean, 1072 +/- 80 cells per section; n = 16 samples) than pig acellularized dermal matrix (mean, 301 +/- 48 cells per section; n = 16 samples). Fibroblasts migrated significantly less (p < 0.05) distance from the cell-seeded pig acellularized dermal matrix surface than in the human acellularized dermal matrix (78.8 percent versus 38.3 percent cells within 150 mum from the surface, respectively; n = 5). Fibroblasts proliferated more rapidly (p < 0.05) on pig acellularized dermal matrix (n = 9) than on the human acellularized dermal matrix (7.4-fold increase in cell number versus 1.8-fold increase, respectively; n = 9 for human acellularized dermal matrix). There was no difference between the two materials with respect to fibroblast adherence (8120 versus 7436 average adherent cells per section, for pig and human acellularized dermal matrix, respectively; n = 20 in each group; p > 0.05). CONCLUSION: Preliminary findings suggest that substantial differences may exist between human fibroblast behavior in cell-matrix interactions of porcine and human acellularized dermis.

Adolescent↗
PubMed2006

Viscoelastic properties of acid- and alkaline-treated human dermis: a correlation between total surface charge and elastic modulus.

BACKGROUND: One of the major mechanical functions of collagenous tissues is the storage, transmission and dissipation of elastic energy during mechanical deformation. In skin, mechanical energy is stored during loading and then is transmitted and dissipated, which protects skin from mechanical failure. Thus energy storage (elastic properties) and dissipation (viscous properties) are important characteristics of extracellular matrices. METHODS: A uniaxial incremental stress relaxation test method has been used to characterize the time-dependent (viscous) and time-independent (elastic) properties of human dermis. Viscoelasticity was investigated in processed human dermis that was equilibrated at pHs of 3.0, 7.4 and 11.0 in an effort to study the link between electrostatic interactions within the collagen matrix and macroscopic tissue properties. RESULTS: Our results show that the solution pH and the charge on collagen significantly affected the high-strain elastic behavior of dermis; the elastic behavior of skin has previously been shown to be directly correlated with axial stretching of the collagen triple helix in crosslinked collagen fibrils. A positive linear correlation existed between the high-strain elastic modulus and both pH (R(2)=0.96) and the total number of charged residues on collagen (R(2)=0.93). These results provide in vitro/ex vivo evidence that charged groups on the surface of collagen molecules in processed human skin influence the high-strain elastic properties of dermis and are likely to be involved in elastic energy storage. CONCLUSION: It is proposed that the pH and charged residue dependency of the elastic modulus suggests that charged pair interactions and repulsions within and between collagen molecules are involved in elastic energy storage during stretching at high strains. It is hypothesized that elastic energy storage is associated with the stretching of pairs of charged amino acid residues that are found primarily in the flexible regions of collagen molecules.

Collagen↗
PubMed2004

Pheomelanin production in the epidermis from newborn agouti mice is induced by the expression of the agouti gene in the dermis.

The present study was designed to clarify the role of the agouti gene in the regulation of the proliferation and differentiation of mouse epidermal melanocytes using serum-free primary culture of epidermal melanocytes from 0.5-d-old black (a/a; C57BL/10JHir) mice and congenic, agouti (A/A; C57BL/10JHir-A/A) mice. There was no significant difference in the proliferation or differentiation of melanocytes between a/a and A/A mice. However, the content of pheomelanin in culture media from A/A melanocytes was increased by L-tyrosine compared with a/a melanocytes. In addition, the content of the pheomelanin precursor, 5-S-cysteinyldopa, in culture media from A/A melanocytes was dramatically increased by L-tyrosine. Moreover, pheomelanin content in the epidermis from 3.5- and 5.5-d-old A/A mice was much higher than in a/a mice. Analysis of the A gene using reverse transcription-polymerase chain reaction revealed that cultured keratinocytes and melanocytes do not express the A gene. Moreover, the A gene was expressed in the A/A dermis of 0.5-, 3.5- and 5.5-d-old mice, but not in the a/a dermis nor in the A/A or a/a epidermis. These results suggest that A/A epidermal melanoblasts are influenced by the A gene from the dermis of neonatal mice, and are capable of synthesizing pheomelanin in the culture. Pheomelanin production in the epidermis from 3.5- and 5.5-d-old A/A mice may be induced by the expression of the agouti gene in the dermis.

Agouti Signaling Protein↗
PubMed2006

Levels of retinyl palmitate and retinol in stratum corneum, epidermis and dermis of SKH-1 mice.

Vitamin A (retinol) regulates many biological functions, including epidermal cell growth. Retinyl palmitate (RP) is the major esterified form of retinol and the predominant component of retinoids in the skin; however, how endogenous levels of RP and retinol in the skin are affected by the age of the animal remains unknown. Furthermore, the levels of retinol and RP in the various skin layers - the stratum corneum, epidermis and dermis of skin - have not been reported. In this paper, we report the development of a convenient method for separation of the skin from SKH-1 female mice into the stratum corneum, epidermis, and dermis and the determination of the levels of RP and retinol in the three fractions by HPLC analysis. The total quantities of RP and retinol from the stratum corneum, epidermis, and dermis are comparable to those extracted from the same amount of intact skin from the same mouse. There was an age-related effect on the levels of RP and retinol in the skin and liver of female mice. An age-related effect was also observed in the stratum corneum, epidermis, and dermis. The levels of RP and retinol were highest in the epidermis of 20-week-old mice, and decreased when the age increased to 60- and 68-weeks. The total amount of RP at 20 weeks of age was found to be 1.52 ng/mg skin, and decreased about 4-fold at 60- and 68-weeks of age. A similar trend was found for the effects of age on the levels of retinol.

Age Factors↗
PubMed2004

Model of human epidermis reconstructed in vitro with keratinocytes and melanocytes on dead de-epidermized human dermis.

CONTEXT: Recent progress in the field of epithelial culture techniques has allowed the development of culture systems in which the reconstructed epidermis presents characteristics of morphological differentiation similar to those seen in vivo. Human epidermis reconstructed in vitro may be used as the best alternative for the in vitro testing of the toxicology and efficiency of products for topical use, as well as in the treatment of skin burns and chronic skin ulcers. OBJECTIVE: To demonstrate a method for obtaining human epidermis reconstructed in vitro, using keratinocytes and melanocytes cultivated on dead de-epidermized human dermis. TYPE OF STUDY: Experimental/laboratory. SETTING: Skin Cell Culture Laboratory of the Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. PROCEDURE: Human keratinocytes and melanocytes cultured in vitro were grown on a biological matrix (dead de-epidermized human dermis) and the system was kept at an air-liquid interface, in a suitable culturing medium, until a stratified human epidermis was formed, maintaining the histological characteristics of the epidermis in vivo. RESULTS: It was histologically demonstrated that it is possible to reproduce a differentiated epidermis through keratinocytes and melanocytes cultured on dead de-epidermized human dermis, thus obtaining a correctly positioned human epidermis reconstructed in vitro with functional keratinocytes and melanocytes that is similar to in vivo epidermis. CONCLUSIONS: It is possible to obtain a completely differentiated human epidermis reconstructed in vitro from keratinocyte and melanocyte cultures on a dead de-epidermized human dermis.

Cell Culture Techniques↗
PubMed2001

Genetic material is present in cadaveric dermis and cadaveric fascia lata.

PURPOSE: We determined whether genetic material is present in the commercially processed cadaveric allografts used in sling surgery. MATERIALS AND METHODS: We evaluated 16 samples from 2 commercial sources of human allograft, including 8 each of freeze-dried gamma irradiated cadaveric fascia lata and acellular cadaveric dermis. Fresh human rectus fascia and sterile saline served as positive and negative controls, respectively. All samples underwent a standard proteinase K/sodium dodecyl sulfate/phenol extraction technique to isolate DNA. Polymerase chain reaction was done to amplify the retrieved DNA material, spectrophotometry to quantify DNA concentration and agarose gel electrophoresis to determine the size of DNA fragments. RESULTS: Of the 16 samples tested from 2 commercial sources of human allograft fascia 14 (87.5%) contained DNA. Mean DNA concentration plus or minus standard error was 258.3 +/- 80.1 and 272.8 +/- 168.8 microg./gm. tissue for cadaveric fascia lata and cadaveric dermis, respectively. Polymerase chain reaction amplified DNA segments of 2,000 bp from 1 of each of the 8 samples of cadaveric fascia lata and cadaveric dermis. CONCLUSIONS: Freeze-dried gamma irradiated cadaveric fascia lata and acellular cadaveric dermis contained intact DNA.

Bioprosthesis↗
PubMed2002

[Application of meshed acellular dermis xenograft (pigskin) with scalp thin skin autograft in 15 patients].

OBJECTIVE: To present the clinical application of the meshed acellular dermis xenograft with scalp thin split-thickness skin autograft. METHODS: The meshed acellular dermis xenograft (pigskin) was placed on the granulation or defects after scar resection. Four or five days afterwards, scalp thin split-thickness skin was transplanted. A total of 15 patients with 25 wounds were treated using this technique. The survival rates and quality of the grafts were observed. RESULTS: The survival rate of the meshed acellular dermis xenograft was (96.40 +/- 2.60)% and the scalp thin split-thickness skin autograft was (97.44 +/- 3.50)%. All grafts showed normal skin-alike color and elastic and smooth texture. CONCLUSION: The combined use of meshed acellular dermis xenograft and scalp skin autograft demonstrated an ideal way for the repair of full-thickness skin burn or defects from scar resection. The scalp can provide thin skin graft repeatedly without influence of the hair.

Adolescent↗
PubMed2002

[Long-term culture of dermis-derived multipotent stem cells and the effects of collagen sponge on their growth in vitro].

Autologous multipotent stem cells are most relevant cells for regenerative medicine and show prosperous future in the treatment of human diseases. Previous reports have indicated that multipotent stem cells (MSCs) can be obtained from bone marrow and adipose tissues. In this study, we proved that dermis may be another source of these cells. MSCs were isolated from the dermis of newborn rats one day old by adhesion competition and successive culture. These cells conserved the ability to differentiate to osteoblasts, chondrocytes and adipocytes by induction media containing dexamethasone. After long term of more than 6 months, till 25th generation, the cells still maintained the characteristics of stem cells: high activity of self-renewal and multipotency. Mixed collagen matrix from dermis could promote the growth of dermis-derived multipotent stem cells and collagen sponge stent could promote their three-dimensional growth in vitro.

Animals↗
PubMed2002

[Integra Artificial dermis in pediatric reconstructive surgery].

UNLABELLED: The recent release of artificial dermis for general use, has open wide a new field in pediatric reconstructive surgery. The aim of this paper is to analyze the results of Integra artificial dermis in our Plastic Surgery Department. MATERIALS AND METHODS: The records of the patients treated with Integra between february 1999 and january 2001 were analyzed, focusing on the indications, the complications and the final results. RESULTS: Fourteen Integra implantation procedures in 11 patients aged 16 months to 12 years (mean +/- SD: 80.9 +/- 48.5 months) were performed. Indications were: acute burns in 5 cases, burns sequelae in 5, and partial extirpation of a congenital giant nevus in the last one. Integra was used to replace between 2 and 30% of total body surface area. The percentage of "take" of skin grafts was 85%. The most frequent early complication was the development of infection under the Integra; it occurred in 2 cases and artificial dermis had to be partially removed. Hypertrophic scars developed in 2 patients; both had refused pressure garments. Cosmetic results in the remaining 9 patients are considered excellent. CONCLUSIONS: The use of artificial dermis has settled as a new procedure in plastic pediatric surgery. In spite of possible complications, the easy manipulation and the good results make Integra a perfect skin substitute in several cutaneous disorders.

Biocompatible Materials↗
PubMed2005

[Experimental study of autologous skin grafting on retained denatured dermis for the treatment of partial thickness burn wound].

OBJECTIVE: To provide experimental evidence for the feasibility of repair of deep partial thickness burn wounds with autologous skin grafting on retained denatured dermis. METHODS: Deep partial thickness burn wounds 3.5 cm x 3.5 cm in size were produced on the back of SD rats. Superficial tangential excision was performed on the burn wounds on 2 - 5 postburn days with the preservation of denatured dermis. Split thickness autoskin was grafted on the wounds immediately. Tissue samples of whole layer of the skin were harvested from the grafted sites at different time points after the skin grafting, with 8 rats in each group. The morphology and the changes in the collagen fibres in the above tissue samples were observed by light microscopy (LM) and the changes in the biodynamics were determined. The normal skin from the same rat receiving skin grafting was employed as the control. RESULTS: (1) Vitreous degeneration was observed in the preserved denatured dermis. (2) The grafted skin was fused to the burn wound on the 7th day after autoskin grafting in rats. The dermal papillae and reticular layer could be discernible under LM. The thickness, structure and morphology of the skin on the grafted area were similar to normal tissue on the 21st day after grafting with atrophic hair follicles. The density of collagen fiber cord increased gradually, and almost fused at last. (3) The tensile strength, and maximum strain value of the rat skin after operation increased gradually, approaching normal on 60 post-operational day. CONCLUSION: The denatured dermis can recover gradually with normal structure and morphology after the application of autoskin on it for the repair of deep partial thickness burn wounds.

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↗
PubMed2003

Analysis of mutation spectra in UVB-exposed mouse skin epidermis and dermis: frequent occurrence of C-->T transition at methylated CpG-associated dipyrimidine sites.

We recently reported the kinetics of mutation induction by UVB in the skin epidermis and dermis of transgenic Muta trade mark mice [Ikehata and Ono, Mutat Res 508:41-47, 2002]. In the present study we determined the complete DNA sequence of the lacZ transgene in 208 mutants isolated from the dermis and epidermis of UVB-irradiated and control mice. The resulting mutation patterns for the dermis and epidermis were similar, although two CC-->TT tandem substitutions, one of the signature mutations for UV insult, were detected only among the UVB-induced epidermal mutants. The spectra of the UVB-induced and control mutations were both dominated by C-->T transitions (83% and 62%); however, the C-->T transitions from irradiated mice occurred almost exclusively in dipyrimidine sites, while those from control mice preferred CpG sites. Thus, the mutation spectrum detected for the irradiated skin tissues was different from the background spectrum and UV-specific, confirming the utility of the transgenic system for UVB-induced mutation studies in vivo. An analysis of the bases adjacent to the mutated cytosines from irradiated mice revealed that the dipyrimidine sites preferred for UVB-induced mutation were 5'-TC-3' > 5'-CC-3' > 5'-CT-3'. Among mutants from irradiated mice, C-->T transitions were recovered frequently at dipyrimidine sites associated with CpG. We showed that CpG sites in the lacZ transgene of Muta trade mark mice were heavily methylated in both the epidermis and dermis. Thus, CpG methylation could contribute to the UVB-induced recurrent or hotspot mutations in the mammalian genome.

Animals↗
PubMed1995

Changes in expression of two endogenous beta-galactoside-binding isolectins in the dermis of chick embryonic skin during development in ovo and in vitro.

In order to elucidate the roles of metal-independent animal lectins, we systematically investigated changes in expression of 2 kinds of beta-galactoside-binding isolectins (MW 14 and 16 kDa) in the dermis of chick embryonic tarsometatarsal skin during the course of development. These lectins were immunohistochemically located at different stages of development both in ovo and in vitro by light and electron microscopy. Light-microscopic observation showed that while positive staining for the 14-kDa lectin was weak at days 8 and 10 it became intense after day 13. In contrast, staining for the 16-kDa lectin was intense at days 8, 10, and 13, but it became weak after day 17 when keratinization of the epidermis was completed. Immuno-electron-microscopic observation revealed that both the 14 and 16-kDa lectins were located on the basement membrane, in the extracellular matrix, and in both the cytoplasm and the nucleus of dermal fibroblasts. Distribution of the 2 isolectins was also examined in cultured skin explants in vitro. The results were almost the same as those obtained in ovo when the skin explant was keratinized in the presence of hydrocortisone. However, in the skin explant where keratinization was prevented and mucous metaplasia was induced by the addition of vitamin A, the distribution of the 14-kDa lectin in the epidermis was significantly affected. These results indicate that (1) the expression of the 2 isolectins is differently regulated in both the dermis and epidermis, (2) the 16-kDa lectin is involved in the early stage of the formation of the dermis and the basement membrane and is replaced by the 14-kDa lectin as keratinization of the epidermis occurs, and (3) the expression of the 2 isolectins in the dermis is not significantly affected by the induction of mucous metaplasia, in contrast to their drastic changes in the epidermis.

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↗
PubMed2007

Sexual function in women after rectocele repair with acellular porcine dermis graft vs site-specific rectovaginal fascia repair.

The objective of the study was to compare preoperative and postoperative sexual function between women undergoing rectocele repair with porcine dermis graft and women undergoing site-specific repair of rectovaginal fascia. A standardized, validated questionnaire (Pelvic Organ Prolapse/Urinary Incontinence Sexual Function Questionnaire [PISQ]) was used to collect preoperative sexual function data from 100 patients with rectocele pelvic organ prolapse quantification stage 2 or greater. Fifty women underwent rectocele repair utilizing porcine dermis graft (group 1) and 50 women underwent a site-specific repair of the rectovaginal fascia (group 2). The same questionnaire was administered to all subjects 6 months after surgery. The two groups were similar in age, race, parity, prior hysterectomy, and postmenopausal hormone use. Preoperative sexual function scores were similar in the two groups (group 1 81.4+/-7.3 and group 2: 83.6+/-8.2, p=1.0). Six months after surgery, PISQ scores in group 1 significantly increased (score increase 19.9+/-2.2, p=0.01). The mean increase in PISQ scores for group 2 was 6.9+/-3.1 (p=0.08). When compared with group 2, subjects undergoing rectocele repair with porcine dermis graft scored significantly higher on the PISQ 6 months after surgery (group 1 101.3+/-6.4 and group 2 89.7+/-7.1, p=0.01). We conclude that rectocele repair using porcine dermis graft is associated with improved sexual functioning when compared with site-specific rectovaginal fascia repair.

Adult↗
PubMed2004

The interpositional dermis-fat graft in the management of temporomandibular joint ankylosis.

The aim of this retrospective clinical study is to present the clinical experience of using dermis-fat interpositional grafts in the surgical management of temporomandibular joint (TMJ) ankylosis in adult patients. Eleven adult patients who presented with ankylosis of the TMJ were identified and included in the study. All patients underwent a TMJ gap arthroplasty which involved the removal of a segment of bone and fibrous tissue between the glenoid fossa and neck of the mandibular condyle. The resultant gap was filled with an autogenous dermis-fat graft procured from the patient's groin. All patients were followed up for a minimum of 2 years. Five of the 11 patients were found to have osseous ankylosis while 6 patients had fibro-osseous ankylosis. Two patients had bilateral TMJ ankylosis that were also treated with costochondral grafts which were overlaid with dermis-fat graft. The average interincisal opening was 15.6 mm on presentation which improved to an average of 35.7 mm following surgery. Patients were followed up from 2 to 6 years post-operatively (mean 41.5 months) with only 1 re-ankylosis identified out of the 13 joints treated. This study found that the use of the autogenous dermis-fat interpositional graft is an effective procedure for the prevention of re-ankylosis up to 6 years following the surgical release of TMJ ankylosis.

Adipose Tissue↗
PubMed2005

Correction of pincer-nail deformities with autograft or homograft dermis: modified surgical technique.

The pincer-nail deformity is characterized by an excessively curved and distorted nail across the transverse dimension. Forty-nine sides (paronychial folds) were dissected off the distal phalanx periosteum with scissors and/or a small elevator. The dermis was placed between the paronychial fold and the plalanx to flatten the germinal and sterile matrix. Direct comparison of autograft dermis to homograft dermis did not show any significant differences in postcorrection appearance of the nail or relief of symptoms. Surgical time averaged 22 minutes less in those patients having reconstruction on both sides of one nail with homograft dermis.

Humans↗
PubMed1981

Fitting of the dermis-fat grafted socket.

Anophthalmic orbits that reject conventional implants may accept the dermis-fat graft. The subsequent fitting of such a socket differs in many important ways from the fitting of sockets containing conventional implants. Before surgery, the ocularist should construct a custom-made scleral ring to be inserted after the operation. This replaces the standard conformer that can erode the underlying dermis. The socket must be observed carefully for any evidence of damage to the conjunctiva-dermis suture line by the ring, and the latter modified or replaced as necessary. Granulation tissue forming around the sutures uniting conjunctiva and dermis may have to be resected and cauterized. Impression molding of an artificial eye is performed five weeks after surgery. The artificial eye always requires modifications over the first six months as the graft recedes due to partial atrophy of the fat of the graft, thus deepening the socket.

Adipose Tissue↗