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Results for “Acellular Dermis”

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At least 127 records · Page 7Linked to original sources

PubMed2003

[The volume change of micronized acellular dermal matrix after injection].

OBJECTIVE: To explore a new injectable material. METHODS: Micronized swine acellular dermal matrix was injected into the ear of rabbits. The augmentation was observed and measured with pathological and transmission electron microscopic technique. RESULTS: There were fibroblasts and capillaries in the injected material. The absorption rate of injected acellular dermal matrix was 26.93% in the experimental group at 48 weeks after injection. CONCLUSION: The acellular dermal matrix is an ideal injectable material for lower absorption and easy usage.

Acellular Dermis↗

PubMed2004

[The development and collagen ingredients analysis of submandibular gland acellular matrix].

PURPOSE: To develop submandibular gland acellular matrix and observe its structure and analyze its histological ingredients. METHODS: The fresh submandibular glands of SD mice were cell-extracted by chemical detergent and histological ingredients were analyzed by immunohistochemistry. RESULTS: Submandibular gland cells disappeared, matrix ingredients appeared network structure under microscopy. I, II and III type collagen proteins of submandibular gland before and after cell-extracted were positive under immunohistochemistry. CONCLUSIONS: The main ingredients of submandibular gland acellular matrix were I, II and III type collagen proteins.

Acellular Dermis↗

PubMed2004

[Penile augmentation using acellular dermal matrix].

OBJECTIVE: Penile enhancement was performed using acellular dermal matrix. METHODS: Multiple layers of acellular dermal matrix were placed underneath the penile skin to enlarge its girth. Since March 2002, penile augmentation has been performed on 12 cases using acellular dermal matrix. RESULTS: Postoperatively all the patients had a 1.3-3.1 cm (2.6 cm in average) increase in penile girth in a flaccid state. The penis had normal appearance and feeling without contour deformities. All patients gained sexual ability 3 months after the operation. One had a delayed wound healing due to tight dressing, which was repaired with a scrotal skin flap. CONCLUSIONS: Penile enlargement by implantation of multiple layers of acellular dermal matrix was a safe and effective operation. This method can be performed in an outpatient ambulatory setting. The advantages of the acellular dermal matrix over the autogenous dermal fat grafts are elimination of donor site injury and scar and significant shortening of operation time.

Acellular Dermis↗

PubMed2006

Acellular dermal allograft for ventral hernia repair in the compromised surgical field.

A ventral hernia and a contaminated surgical field are a difficult surgical combination. We hypothesize that acellular human dermis (AHD) can be a suitable biological tissue alternative in the repair of a ventral hernia. The study involved a retrospective review of the use of AHD in the repair of ventral hernia from 2001-2004. Inclusion criteria included a ventral hernia repair in a clean-contaminated (CC) or contaminated-dirty (CD) surgical field. The primary outcome of the study was wound infection and mesh removal. Patients were stratified into CC and CD, and management of a wound infection [medically managed (MM) or surgically managed (SM)]. Seventy-five patients met the study criteria. The most common comorbidity was hypertension (45.3%). There was one death in the study (from multiple organ dysfunction syndrome). The overall wound infection rate was 33.3 per cent: 11 MM (14.7%) and 14 SM (18.7%). The average length of stay was 16.7 days (+/-20.8) with a mean follow-up of 275 (+/-209) days. Subgroup analysis: CC (n = 64) had 9 wound infections that were MM (14.1%) and 12 wound infections that were SM (18.8%); CD (n = 11) had 2 wound infections that were MM (18.2%) and 2 wound infections that were SM (18.2%). Five of 14 SM (35.7%) wound infections required removal of the mesh. Wound infection in the contaminated surgical field occurred 33.3 per cent of the time. Some (18.7%) of the cases required SM management, and 35.7 per cent of these required removal of the AHD.

Adolescent↗

PubMed2006

Comparison of biomechanical properties of alloderm and enduragen as static facial sling biomaterials.

BACKGROUND: Static slings are one of the most commonly used surgical rehabilitation methods in the management of chronic facial paralysis. Acellular human cadaveric dermis (Alloderm; Life Cell Corp., Branchburg, NJ) is used for this purpose; however, it has variable stretching properties that may necessitate additional "tuning-up" procedure(s). Acellular porcine dermis (Enduragen; Tissue Sciences Laboratories, plc., Aldershot, U.K.) was recently introduced as a biologic implant and it is compositionally similar to Alloderm. However, no data currently exist regarding its biomechanical properties and potential use as an alternative implant to Alloderm in static facial sling procedures. OBJECTIVE: The objective of this study was to compare the biomechanical properties of Alloderm and Enduragen for static facial sling procedures in the management of the paralytic face. STUDY DESIGN: This study consisted of an in vitro prospective study in an academic medical research setting. METHODS: Same size and thickness Alloderm and Enduragen samples were tested with MTS 858 Bionix materials test system for load-to-failure, displacement under increasing and constant stress, and stiffness. RESULTS: Enduragen showed significantly less elongation under increasing stress and at the beginning of constant stress. Load-to-failure and stiffness were significantly higher in Alloderm; however, both biomaterials have adequate stiffness and load-to-failure for a static facial sling procedure. CONCLUSIONS: Enduragen may serve as another potential static facial sling material, because it stretches significantly less than Alloderm under stress. Clinical experience is needed with Enduragen to determine its potential use as a static facial sling material.

Biocompatible Materials↗

PubMed1999

Use of an acellular dermal allograft for dural replacement: an experimental study.

OBJECTIVE: In this study, a nonimmunogenic, acellular, dermal collagen matrix termed XenoDerm (LifeCell Corp., The Woodlands, TX) was examined for use as a dural replacement material in a porcine model. This model was used to investigate whether AlloDerm (LifeCell), an almost identical material made from human dermis, could be safely used in neurological surgery. METHODS: Bilateral temporoparietal dural defects were surgically created in 12 Yucatan minipigs. One side was repaired with autologous pericranium, and the other was repaired with XenoDerm. The pigs were killed after 1, 3, or 6 months, and the areas of dural repair were collected and examined macroscopically and histologically. XenoDerm is derived from porcine skin collected in thin sheets. It is processed so that the epidermis and all dermal cells are removed without disruption of the collagen matrix, rendering the material immunogenically inert and resistant to calcification. It is packaged as a freeze-dried sheet and is easily rehydrated at the time of surgery. RESULTS: There were no postoperative complications, and all pigs survived. Both grafts performed well as dural replacements in all cases. There was no macroscopic evidence of inflammation or cerebrospinal fluid leakage. The XenoDerm grafts were intact, retained their original dimensions, and resembled the surrounding dura. The autologous pericranial grafts, in contrast, were thicker than when implanted and had bony excrescences firmly adhering to their surfaces. Again, however, there was no evidence of cerebrospinal fluid fistulae. There was no gross adherence to the underlying meninges or brain tissue in any specimen. Repopulation by fibroblasts and neovascularization were evident in the XenoDerm grafts as early as 1 month after surgery; by 3 months, the XenoDerm had been remodeled to assume the connective tissue appearance of the surrounding dura. CONCLUSION: In this porcine model, an allograft of acellular dermis is a nearly ideal dural replacement. AlloDerm, the human equivalent of XenoDerm, would be an allograft of acellular dermis after implantation in human subjects. On the basis of this study and previous work with AlloDerm in other reconstructive applications, it is proposed that this material could be similarly used for duraplasty in human subjects.

Animals↗

PubMed1999

Dural reconstruction of a class IV calvarial burn with decellularized human dermis.

Calvarial burns involving the brain (Class IV) are reported to be rare. They represent a treatment challenge. Wound coverage can be accomplished with serial debridement of bone and grafting over granulating tissue, local flaps and free tissue transfer. The former techniques are often not feasible in the young infant. We present a successful case of a six-week-old female patient affected of full thickness burns involving the skull and brain. The bone, dura mater and superficial brain were debrided and the defect covered with AlloDerm and split thickness grafts. The area engrafted completely and no complications or CSF leak occurred. An acellular human allogeneic dermis (AlloDerm) can be successfully used to replace dura mater in burn patients.

Brain Injuries↗

PubMed2002

[Studies on xenogenic acellular dermal matrix as a filling material].

OBJECTIVE: To explore the biological reaction of swine acellular dermal matrix as a filling material for body surface deformity. METHODS: Xenogenic acellular dermal matrix was implanted into the hypoderm of rabbits. The implants were measured and observed with pathological and transmission electron microscopic technique at regular times. The results were compared with implantation of autologous dermis and swine dermis. RESULTS: The implanted xenogenic acellular dermal matrix and autologous dermis had slight inflammatory reaction. At 2 weeks there were fibroblasts and capillaries in the implants. The absorptivity of the xenogenic acellular dermal matrix was lower than the swine dermis. The xenogenic acellular dermal matrix was used in 2 clinical cases and obtained good result. CONCLUSION: The xenogenic acellular dermal matrix is an ideal material with good compatibility feature and low absorptivity.

Animals↗

PubMed2004

[The clinical application on composite graft of acellular allo-dermal matrix and auto-microskin on escharectomy after deep burns].

OBJECTIVE: To present the clinical application of composite graft of acellular allo-dermis matrix (ADM) with thin auto-microskin on burn wound. METHODS: 8 inpatients with 18 full thickness skin burn wounds were transplanted with allo-ADM after eschar was excised, then the auto-microskin and allo-human skin were covered on the area of the matrix, the wound where no allo-ADM grafting were covered as control groups only with auto-microskin and allo-human skin. The area of donor to wound is 1:5 - 1:8. RESULTS: Survived rate of 18 pieces composite skin that allo-ADM with auto-microskin were grafted were 94%. After following up for 3 to 13 months, the skins of complex grifting had well elastic and smooth texture compared to auto-microskin grafted, they appeared less cicatrisation and ulceration. 3 months after operation, it was indicated by histological examination that tightknit the epithelial-dermal conjunction and epidermal papilla structure could be identified in the allo-ADM skin and there were orderly collagenous fibres, but scar skin structure was observed in that auto-microskin grifted area. CONCLUSION: The graft effectiveness of allo-ADM and auto-microskin was better than that of auto-microskin, and this method could be used on major deep burn wound healing.

Adult↗

PubMed1995

Transplanted acellular allograft dermal matrix. Potential as a template for the reconstruction of viable dermis.

The use of allograft donor skin as a permanent skin transplant in full-thickness burns is limited by its immunogenic properties and by the inappropriateness of immunosuppression of a burn patient. Allograft skin will initially take on a full-thickness wound, but it is ultimately rejected. This immunogenic response to allograft skin is directed primarily against the cells of the epidermis and the endothelial cells in the dermis. To date, it has not been possible to remove these immunogenic cells while maintaining the integrity of the nonimmunogenic components of allograft dermis. In this study, we have investigated a method of processing porcine skin to produce an acellular, structurally intact, dermal matrix. We have developed a process that de-epidermizes and decellularizes fresh porcine skin, while maintaining the basement membrane complex and the extracellular matrix structure of the dermis. Porcine dermis processed by this method was initially assessed for toxicity in a rat subcutaneous implant study. In vivo assessment confirmed the absence of local and systemic toxicity. Subsequently, we investigated the potential use of this matrix in combination with a meshed split-thickness autograft (STSG) as a permanent allograft in full-thickness wounds in pigs. Histological analysis revealed that the dermal matrix supported fibroblast infiltration, neovascularization, and keratinocyte migration from an overlying STSG. There was no evidence of an inflammatory cell infiltrate or a cell-mediated immune response. This apparent lack of an immune response was also tested in vitro by assessing recipient lymphocyte proliferation in response to an extract of the dermal matrix. These results suggest that skin processed by this method has the potential to be used as a permanent dermal allograft to augment the performance of an STSG in the closure of full-thickness wounds.

Animals↗

PubMed1997

Comparison of an in vitro skin model to normal human skin for dermatological research.

EpiDerm, an in vitro human skin equivalent (HSE), was compared to normal human breast skin (NHS) to morphologically and biochemically assess its feasibility for dermatological research. Intralot and interlot variability was studied in day 0, 1, 2, and 3 in vitro cultures and in day 0, 3, 5, and 7 NHS. For NHS, light microscopy (LM) at day 0 showed stratified epidermis which exhibited an increase in vacuoles and dark basal cells as storage increased to 3, 5, and 7 days. Transmission electron microscopy (TEM) revealed typical organelles in the epidermis and a convoluted basement membrane at day 0. With increased storage, vacuoles and paranuclear clefts became numerous, necrosis increased, tonofilaments became less organized, and overall cellular integrity decreased. Biochemical data showed consistent MTT and glucose utilization (GU) through day 5, while lactate production decreased to 75% by day 3. By LM, day 0 HSE consisted of a thick, compact, stratum corneum that sent projections between the stratum granulosum cells. By TEM, the configuration organization, differentiation, distribution, and frequency of the organelles differed slightly from NHS. In addition, the basement membrane of the HSE was not completely differentiated, and the dermis was thin and acellular. Although day 1 and 2 cultures showed little change, day 3 exhibited an overall degeneration. Biochemical analysis showed GU and the lactate production decreased through day 3. In conclusion, the EpiDerm HSE, although exhibiting slight differences, was morphologically and biochemically similar to normal human epidermis and may be a valuable model in assessing the toxicology, metabolism, or pharmacology of nonvesicating compounds.

Cell Survival↗

PubMed1996

Influence of extracellular matrix proteins on human keratinocyte attachment, proliferation and transfer to a dermal wound model.

The aim of this study was to investigate whether prior culture of cells on ECM proteins might positively influence the performance of keratinocytes when cells are transferred to a dermal in vitro wound bed model. Keratinocytes were cultured using a method for producing cultured epithelial autografts for severely burned patients (essentially using Green's medium, a mitogen-rich medium containing fetal calf serum, cholera toxin, EGF, insulin, transferrin and triiodothyronine). Cells were cultured either on irradiated 3T3 fibroblasts (as in the standard Rheinwald and Green technique) or, alternatively, on collagen I, collagen IV, matrigel, RGD, vitronectin or fibronectin. Under these conditions matrigel, collagen I and IV enhanced initial attachment, RGD, vitronectin, fibronectin and irradiated 3T3 fibroblasts did not. Proliferation of cells was positively influenced by matrigel, collagen I and IV and irradiated 3T3 fibroblasts; of these, however, only matrigel and 3T3 fibroblasts had sustained significant effects on keratinocyte proliferation over 4 days. Cells on fibronectin showed significantly reduced proliferation. An acellular non-viable dermis was then used to mimic the homograft allodermis onto which cultured epithelial autograft sheets are grafted clinically and cells cultured on the various ECM proteins for 96 h were transferred to this in vitro wound model. None of the substrates enhanced keratinocyte performance on this model. It was concluded that under these conditions some ECM proteins can significantly affect keratinocyte attachment and, to a lesser extent, proliferation but that the culture of keratinocytes on these ECM proteins does not appear to confer any lasting benefit to the attachment of these keratinocytes to an in vitro wound-bed model.

Cell Division↗

PubMed1999

Ex vivo development of a composite human oral mucosal equivalent.

PURPOSE: The aim of this study was the ex vivo development of a composite oral mucosal equivalent composed of a continuous stratified layer of human oral keratinocytes grown on a cadaveric human dermal matrix in a defined medium without a feeder layer. MATERIALS AND METHODS: Enzymatically dissociated human oral keratinocytes from keratinized oral mucosa were cultured, submerged in a serum-free, low-calcium (0.15 mmol/L) supplemented medium, and expanded through several passages. Once a sufficient population of keratinocytes was reached, they were seeded on 1-cm2 pieces of AlloDerm (LifeCell Co, Woodlands, TX), an acellular nonimmunogenic cadaveric human dermis, at cell densities of 2.5 X 10(4), 5.0 X 10(4), 1.25 X 10(5), or 2.5 X 10(5). The oral keratinocyte-AlloDerm composites were cultured while submerged in a high-calcium (1.8 mmol/L) medium for 4 days. After 4 days, the composites were raised to an air-liquid interface. Samples of the composites were taken for histologic examination at 4, 11, and 18 days postseeding of the keratinocytes on the AlloDerm. RESULTS: At day 4, only the seeded cell density of 2.5 X 10(5) cells/cm2 formed a continuous monolayer on the AlloDerm. At day 11, a continuous stratified epithelium was seen, and at day 18 a well-differentiated, confluent parakeratotic epithelial layer was developed at cell densities of 5.0 X 10(4), 1.25 X 10(5), and 2.5 X 10(5)cells/cm2. CONCLUSION: With the method used, it was possible to successfully develop an ex vivo composite oral mucosal equivalent that consisted of a stratified epidermis on a dermal matrix.

Calcium↗

PubMed2002

Fibroblasts play a regulatory role in the control of pigmentation in reconstructed human skin from skin types I and II.

Human melanocytes in monolayer culture are extremely dependent on a wide range of soluble signals for their proliferation and melanogenesis. The advent of three-dimensional models of reconstructed skin allows one to ask questions of how these cells are regulated within a setting which more closely approximates normal skin. The purpose of this study was to investigate to what extent melanocytes within a reconstructed skin model are sensitive to regulation by dermal fibroblasts, basement membrane (BM) proteins and the addition of alpha-melanocyte-stimulating hormone (alpha-MSH). Sterilized acellular de-epidermized dermis (prepared to retain BM proteins or deliberately denuded of BM by enzymatic treatment) from skin type I or II was reconstituted with fibroblasts, melanocytes and keratinocytes. In all but one case (9/10), cell donors were skin type I or II. The presence of BM antigens was found to be necessary for positional orientation of the melanocytes; in the absence of BM, melanocytes moved into the upper keratinocyte layer pigmenting spontaneously. Addition of fibroblasts suppressed the extent of spontaneous pigmentation of melanocytes within this model. Neither alpha-MSH nor cholera toxin induced pigmentation in this model despite the fact that melanocytes clearly had the ability to synthesize pigment.

Adult↗

PubMed2007

Xenograft use in reconstructive pelvic surgery: a review of the literature.

Xenografts, bovine or porcine acellular collagen bioprostheses derived from dermis, pericardium, or small-intestine submucosa, were introduced to overcome synthetic mesh-related complications. Although there are eight commercially available xenografts, there is a paucity of empiric information to justify their use instead of the use of synthetic grafts. In addition, limited data are available about which graft characteristics are important and whether graft-reinforced repairs reduce recurrences and improve outcomes. To address these knowledge gaps, we conducted a Medline search of published reports on xenografts in animal and human trials. Histologic host response to implanted xenograft material depends primarily on chemical cross-linking and porosity, and it is limited to four responses: resorption, incorporation, encapsulation, and mixed. No clinical data unequivocally demonstrate an improved benefit to graft-reinforced repair.

Animals↗

PubMed2001

Collagenous and elastotic marginal plaques of the hands.

A 49-year-old woman presented with an asymptomatic indurated linear plaque extending from the medial surface of the right thumb along the junction of the dorsal and palmar skin of the hand onto the lateral aspect of the index finger. The left hand showed a similar but less extensive plaque. A skin biopsy showed an acellular zone in the reticular dermis composed of thickened bundles of collagen haphazardly arranged, some perpendicular to the epidermis, admixed with elastic fibres and amorphous basophilic elastotic material. Granular calcium deposits were identified, particularly within degenerate collagen bundles. These clinical and histological features are diagnostic of collagenous and elastotic marginal plaques of the hands, a slowly progressive but largely asymptomatic condition. Actinic degeneration and chronic pressure have been proposed as aetiological agents, but our patient did not exhibit marked actinic degeneration and had no history of chronic occupational pressure.

Diagnosis, Differential↗

PubMed2000

Penetration of human metastatic melanoma cells through an authentic dermal-epidermal junction is associated with dissolution of native collagen types IV and VII.

The events occurring during the penetration of melanoma cells through the dermal-epidermal junction, which is the first crucial step in the process of metastasis, are poorly understood, partly because no suitable tissue models exist. In the in vitro model reported here, two melanoma clones (T1C3, which generates lung metastases in experimental animals, and IC8, which does not) derived from a single parental cell line were co-seeded with normal allogenic keratinocytes onto acellular human de-epidermized dermis with preserved intact basement membrane and cultured for up to 1 month at an air-liquid interface. Histological, immunohistochemical and ultrastructural studies showed that melanoma cells from the metastatic clone (T1C3), but not from the non-metastatic clone (IC8), penetrated the dermal-epidermal junction to invade the dermis after 3 weeks of culture. Local invasion was associated with the dissolution of the native epidermal basement membrane collagens type IV and VII. Confocal laser scanning microscopy analysis demonstrated that numerous T1C3 cells were able to colonize the interstitial dermis and to rapidly penetrate empty dermal cavities. Our model represents a significant technical advance over others currently available since: (i) the organized three-dimensional architecture of the native dermal-epidermal junction is preserved; (ii) the active invasion process coincides with the dissolution of native components of the epidermal basement membrane, i.e. collagen types IV and VII; and (iii) the ability of melanoma cells to cross the dermal-epidermal junction correlates with their metastatic potential. This model provides a valuable tool for the study of the time-course of the cellular and molecular events that occur during the earliest steps of invasion in cutaneous melanoma. It also offers new opportunities to study the possible role of the keratinocyte environment in melanoma invasion.

Basement Membrane↗

PubMed2000

Long-term follow-up study of artificial dermis composed of outer silicone layer and inner collagen sponge.

In the oriental population including the Japanese, donor-site hypertrophy is more pronounced than in Caucasians. To solve the problem of donor-site morbidity and to ensure graft 'take', we started the second-stage procedure of a thin split thickness skin graft (STSG) onto acellular 'bilayer artificial skin', or 'artificial dermis'. Since reporting the original version of the material (OV), a revised version (RV) and the present version (PV, Pelnac) have been developed in stages to eliminate inconveniences associated with its use and to reduce the primary cost of manufacture. We have now used our materials, consisting of OV, RV and PV, on 52 skin defects in 41 patients. STSG took almost perfectly in all patients. The long-term results of these three materials were investigated in 20 patients who had been followed up for more than 2 years, excluding three patients whose donor sites had been directly closed. The longest and the mean follow-up periods of these patients were 12 years 5 months and 6 years 10 months, respectively. At the grafted sites, wrinkles caused by shrinkage, partial depigmentation and hypertrophy were observed in five (25%), one (5%) and one (5%) of the 20 patients, respectively. At the donor sites, slight unsightliness was observed in five (25%) of the 20 patients. Excellent or good results were obtained in 18 (90%) of the 20 patients in comprehensive evaluation. There were no significant differences in the long-term follow-up evaluations among these materials. In conclusion, the long-term postoperative appearance of the STSG site was good though a very thin (approximately 0.2mm) STSG is used; scarring of the donor site was minimal and it was possible to take repeated skin grafts from the same donor site.

Adolescent↗