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Results for “Acellular Dermis”

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At least 55 records · Page 3Linked to original sources
PubMed2004

[Development of selective acellular porcine skin and its preliminary clinical application on burn wounds].

OBJECTIVE: To develop a new kind of skin substitute, selective acellular porcine skin, to cover excised wounds in treatment of extensive deep burns on the basis of controlled de-cell technique. METHODS: Partial thickness porcine skin was treated with 0.25% trypsin for 2 hours at 37 degrees C after crosslinked with glutaraldehyde, and then it was glued to a container with the edge embedded with glue. The skin was shaken in 0.5% SDS for 24 hours, and then washed before use. The selective acellular skin was used with micro-autografts on the dermal side to cover 2 surgically excised burn wounds in a patient. The recoveries of function and appearance were observed. RESULTS: Morphological observation showed that the treated porcine skin had an intact epithelial layer and an acellular dermis. After being used to cover burn wounds, its acellular dermis could serve as host dermal matrix, and its devitalized epithelial layer could prevent the dermis from drying. The devitalized epithelium was finally replaced by host epithelial cells, and the healed wounds could achieve good cosmetic and functional results. CONCLUSION: Selective acellular porcine skin can be used as promising skin substitute to cover excised wounds.

Adult↗
PubMed2005

[Experimental study of using acellular dermal dermis instead of donor sclera in orbital implantation].

OBJECTIVE: To evaluate the histocompatibility of homologous acellular dermal matrix as a wrapping material for a hydroxyapatite orbital implant and compare the speed of fibrovascular ingrowth in hydroxyapatite orbital implant wrapped with homologous acellular dermal matrix and homologous sclera respectively. METHODS: Twenty four New Zealand rabbits were divided into two groups randomly. One group is implanted with hydroxyapatite orbital implant wrapped with homologous acellular dermal matrix behind the globe, the other group with homologous sclera. The observation included immunological reaction of the globe postoperation. Biopsies of implanted material were taken on weeks 1, 4, 8 and 12 postoperation for histopathological and electron microscope examination. RESULTS: Histological examination showed the homologous acellular dermal matrix has no immunological and inflammatory reaction after implanted in orbit. But the speed of fibrovascular ingrowth is a little slower than that of homologous sclera. CONCLUSIONS: The homologous acellular dermal matrix has the better histocompatibility as an encapsulating biomaterial, it can be a new material instead of homologous sclera.

Animals↗
PubMed2000

Early results of vermilion lip augmentation using acellular allogeneic dermis: an adjunct in facial rejuvenation.

The definitive approach to lip augmentation has yet to be defined. Herein is described a technique using acellular allogeneic dermal grafts that is easy, effective, and reproducible. Our results over the past 2 years include 47 patients (94 grafts). Three grafts to the upper lip have exhibited significant resorption, which warranted further augmentation. Early in the series, one graft was malpositioned too superiorly along the vermilion-cutaneous border. There have been no cases of infection, hematoma, or graft exposure. The overall complication rate was 4 percent (4 of 94). Our early results by using acellular allogeneic dermal grafts for lip augmentation are encouraging. Further studies are under way to better objectively define long-term results.

Adult↗
PubMedDate not supplied

Acellular human dermis promotes cultured keratinocyte engraftment.

In full-thickness skin injury, loss of dermis may result in compromised wound repair, including contracture, hypertrophic scarring, and wound breakdown. This report examines the effect of an acellular dermal matrix on in vivo skin repair. Human keratinocytes cultured onto a synthetic hydrophilic dressing were applied with (N = 9) and without (N = 11) an acellular dermal matrix to full-thickness skin defects on athymic mice. Host cells progressively repopulated the acellular dermal component of the grafts. All animals with dermal matrix revealed fully differentiated epidermis by postoperative day 21. Human keratinocytes persisted in all animals grafted with dermal matrix, compared to only 63.6% of those animals without a dermal component. Planimetric analysis revealed significantly reduced wound contraction (p = 0.016) in animals receiving the dermal matrix. Histologic, immunohistochemical, and electron microscopic analyses also were performed. These studies suggest that an acellular dermal matrix can effectively direct regeneration of normal skin morphology.

Animals↗
PubMed1996

Acellular human dermal matrix as a small vessel substitute.

In both vascular and microvascular surgery, there is a need for a non-thrombogenic, small-caliber, arterial substitute. Clinically, most vessel substitutes with diameters under 4 mm have low patency rates. An arterial conduit made from a biocompatible human acellular dermis may be useful as a small vessel conduit. The purpose of this study was to evaluate and compare the patency rates of a vascular conduit made from rolled human acellular dermal (ACD) matrix and a similar-sized polytetrafluoroethylene (PTFE) tube, using the rat femoral artery interposition model. Twenty-eight days after implantation, 9 or 10 (90 percent) ACD grafts and 5 of 8 (62.5 percent) PTFE grafts were patent. False aneurysms formed in 6 ACD conduits along the longitudinal suture line. The three patent non-aneurysmal ACD conduits developed an endothelial luminal lining. While further studies are needed, acellular dermis appears to be a promising material for use as a vessel substitute.

Aneurysm, False↗
PubMed2000

Dural repair using acellular human dermis: experience with 200 cases: technique assessment.

OBJECTIVE: Many craniotomies require a watertight dural closure. When primary dural repair is not possible, a graft is necessary. Autograft material is not always easily accessible or available, necessitating the use of other material. We performed 200 craniotomies using an acellular human dermal graft (AlloDerm; LifeCell Corp., The Woodlands, TX) to determine its suitability as a dural substitute. METHODS: From June 1996 through March 1998, all patients at Allegheny General Hospital who required a dural substitute graft and in whom autograft harvest was impractical or impossible received the acellular dermal autograft. The running suture technique was used to form a watertight seal. RESULTS: After follow-up for a minimum of 1 year, seven patients have required subsequent surgery. Three patients developed cerebrospinal fluid leaks that were repaired without removing the dermal graft. Four patients developed wound infections that required debridement. In each patient, the graft seemed to be uninvolved in the infectious process and was left in place. The patients were administered antibiotics postoperatively, and there have been no recurrent infections. No adhesion formation or scarring was noted around or underneath the graft in any patient. CONCLUSION: AlloDerm is a reasonable alternative to the available dural graft materials. Its handling characteristics are similar to those of dura, it is biologically inert, and it does not produce adhesion formation.

Biological Dressings↗
PubMed2001

Clinical evaluation of acellular allograft dermis for the treatment of human gingival recession.

BACKGROUND: Periodontal root coverage procedures to treat recession areas are indicated for unesthetic, exposed, and/or painful root surfaces. Many methods, most using autogenous soft tissue grafts, have been utilized, but with associated morbidity at the donor sites. An alternative donor material would reduce the morbidity and provide for sufficient available donor tissue. METHODS: An acellular allogeneic dermal connective tissue matrix (AD) and autogenous palatal connective tissue (CT) were compared as subepithelial grafts for the treatment of gingival recession. Twenty-two patients with similar isolated gingival recession of > or = 2 mm on 2 separate teeth were treated with the subepithelial graft technique. Exposed roots were hand root planed only and, by random allocation, either a fitted AD or fitted CT graft was secured in place and covered by coronally positioned flaps. RESULTS: Mann Whitney U test analysis found the following changes at 6 months for AD and CT, respectively, compared to presurgical conditions: root coverage of 1.7 +/- 1.2 (65.9%) and 2.2 +/- 1.1 mm (74.1%) (both P<0.01), increase in keratinized tissue (KT) of 1.2 +/- 1.3 and 1.6 +/- 1.9 (both P<0.01), and an increase in gingival thickness with both; 83.2% of expected root coverage was obtained with AD and 88.6% with CT (P= 0.43). There were no significant differences between treatments for any parameter. Global assessments by clinicians and patients suggested a more esthetic clinical result with AD. CONCLUSIONS: These results suggest that acellular allogeneic dermal matrix may be a useful substitute for autogenous connective tissue grafts in root coverage procedures.

Adult↗
PubMed1998

Genetically modified human keratinocytes overexpressing PDGF-A enhance the performance of a composite skin graft.

Skin loss due to burns and ulcers is a major medical problem. Bioengineered skin substitutes that use cultured keratinocytes as an epidermal layer with or without analogues of the dermis are one strategy for skin repair. However, none can achieve definitive wound closure, function, or cosmesis comparable to split-thickness autografts. Moreover, autograft donor sites, which require time to heal, may be limited or have attendant problems such as infection or functional/cosmetic deficiencies. To determine if the performance of composite skin grafts of keratinocytes on a dermal analogue could be enhanced, human keratinocytes were genetically modified to overexpress platelet-derived growth factor A chain (PDGF-A). Composite grafts of modified keratinocytes seeded onto acellular dermis, prepared from cryopreserved cadaver skin, secreted PDGF-AA protein in vitro [90 ng/graft (1.5 x 1.5 cm)/24 hr]. To test their performance in a wound healing model, composite grafts were transplanted to full-thickness excisional wounds on the back of athymic mice. PDGF-A grafts formed a stratified differentiated epidermis similar to control grafts. The acellular dermis was repopulated with host fibrovascular cells and by day 7, the PDGF-A grafts had significantly more cells in the dermis and increased staining for murine collagen types I and IV. At this early time point, wound contraction was also significantly inhibited in PDGF-A grafts versus control grafts. Thus, PDGF-A overexpression improves graft performance during the first critical week after transplantation.

3T3 Cells↗
PubMed2003

Engraftment of a vascularized human skin equivalent.

Clinical performance of currently available human skin equivalents is limited by failure to develop perfusion. To address this problem we have developed a method of endothelial cell transplantation that promotes vascularization of human skin equivalents in vivo. Enhancement of vascularization by Bcl-2 overexpression was demonstrated by seeding human acellular dermis grafts with human umbilical vein endothelial cells (HUVEC) transduced with the survival gene Bcl-2 or an EGFP control transgene, and subcutaneous implantation in immunodeficient mice (n=18). After 1 month the grafts with Bcl-2-transduced cells contained a significantly greater density of perfused HUVEC-lined microvessels (55.0/mm3) than controls (25.4/mm3,P=0.026). Vascularized skin equivalents were then constructed by sequentially seeding the apical and basal surfaces of acellular dermis with cultured human keratinocytes and Bcl-2-transduced HUVEC, respectively. Two weeks after orthotopic implantation onto mice, 75% of grafts (n=16) displayed both a differentiated human epidermis and perfusion through HUVEC-lined microvessels. These vessels, which showed evidence of progressive maturation, accelerated the rate of graft vascularization. Successful transplantation of such vascularized human skin equivalents should enhance clinical utility, especially in recipients with impaired angiogenesis.

Animals↗
PubMed1997

Keratinocytes contract human dermal extracellular matrix and reduce soluble fibronectin production by fibroblasts in a skin composite model.

Composites of human de-epidermised acellular dermis and normal adult human keratinocytes and fibroblasts were examined for the ability of cells to contract these composites. Image analysis of the outline of the composites showed that, in this model, keratinocytes alone or in the presence of fibroblasts caused highly significant contraction (of the order of 25% by day 12). There was no significant contraction of the dermis with fibroblasts alone or in the absence of cells. The presence or absence of basement membrane antigens did not influence the effect of keratinocytes on dermal contraction. Analysis of the conditioned media from these composites showed that the greatest fibronectin production was seen with fibroblasts alone in the presence of basement membrane. Keratinocytes alone produced little fibronectin irrespective of the presence of the basement membrane. If keratinocytes were present with fibroblasts, however, then fibronectin production was significantly reduced both in the presence and absence of the basement membrane, indicating that keratinocytes modify dermal fibroblast extracellular matrix production. This study shows that while keratinocytes and fibroblasts are clearly influencing each other's activity in this human skin composite model, under the circumstances we describe it is the keratinocyte and not the fibroblast which causes contraction of the human de-epidermised acellular dermis.

Adult↗
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

Diaphragmatic reconstruction with autologous tendon engineered from mesenchymal amniocytes.

PURPOSE: This study examined the effects of amniocyte-based engineered tendons on partial diaphragmatic replacement. METHODS: Ovine mesenchymal amniocytes were labeled with green fluorescent protein (GFP), expanded, and seeded into a collagen hydrogel. Composite grafts (20 to 25 cm2) based on acellular dermis (group I), or acellular small intestinal submucosa (group II) received either a cell-seeded or an acellular hydrogel within their layers. Newborn lambs (n = 20) underwent partial diaphragmatic replacement with either an acellular or a cellular autologous construct from either group. At 3 to 12 months' postoperatively, implants were subjected to multiple analyses. RESULTS: Diaphragmatic hernia recurrence was significantly higher in animals with acellular grafts (5 of 5) then in animals with cellular ones (1 of 4) in group I (P <.05) but not in group II (3 of 6 and 4 of 5, respectively). Cellular grafts had higher modular (5.27 +/- 1.98 v. 1.27 +/- 0.38 MPa) and ultimate (1.94 +/- 0.70 v. 0.29 +/- 0.05 MPa) tensile strength than acellular implants in group I (P <.05), but not in group II. Quantitative analyses showed no differences in extracellular matrix components between cellular and acellular implants in either group. All cellular implants showed GFP-positive cells. CONCLUSIONS: Diaphragmatic repair with an autologous tendon engineered from mesenchymal amniocytes leads to improved mechanical and functional outcomes when compared with an equivalent acellular bioprosthetic repair, depending on scaffold composition. The amniotic fluid may be a preferred cell source for engineered diaphragmatic reconstruction.

Amniotic Fluid↗
PubMed2005

Comparison of the efficacy of hard palate grafts with acellular human dermis grafts in lower eyelid surgery.

BACKGROUND: The Madame Butterfly procedure of lower eyelid reconstruction addresses lower eyelid retraction after blepharoplasty caused by middle lamellar tethering. After scar lysis and subperiosteal midface lift, the surgical procedure uses a lower eyelid spacer graft to prevent further postoperative contraction of the middle and posterior lamellae. Different graft materials have been used, including autogenous hard palate and AlloDerm. METHODS: The preoperative and postoperative photographs of consecutive patients who had undergone the Madame Butterfly procedure were analyzed retrospectively. Thirty-five patients undergoing AlloDerm grafting were compared with 25 patients undergoing hard palate grafting. Their lower eyelid heights were digitally measured and analyzed statistically for differences between the two groups. RESULTS: No statistically significant difference was found in the amount of eyelid elevation between the AlloDerm and hard palate groups, although a trend was seen that hard palate grafts resulted in both better elevation (p = 0.121) and a lower failure rate (p = 0.092). Female patients in both groups were found to experience significantly greater eyelid elevation than male patients (p = 0.018). CONCLUSIONS: Both AlloDerm and hard palate were found to be successful grafting materials for lower eyelid elevation in patients with postblepharoplasty lower eyelid retraction. Each has advantages and disadvantages, and surgeons should tailor their choices according to each patient.

Adult↗
PubMed2004

Acellular cadaveric dermis (AlloDerm): a new alternative for abdominal hernia repair.

AlloDerm is an intact human tissue matrix with the critical biochemical and structural components of the dermal extracellular scaffold that enable it to recellularize and revascularize. Its biologic nature provides AlloDerm with an improved capacity to reintegrate with surrounding tissues and less inclination toward infection, erosion, extrusion, and rejection compared with synthetic tissue replacement materials. This retrospective review describes the experience with AlloDerm for incisional hernia and transverse rectus abdominis musculocutaneous flap reconstructions at a plastic surgery practice that handles complex, nonprimary repairs. AlloDerm was observed to provide exceptional safety and tolerability, and to become reintegrated and vascularized with surrounding tissue for tolerable and persistent tissue replacement.

Adult↗
PubMed1997

Treatment of burns and donor sites with human allogeneic keratinocytes grown on acellular pig dermis.

The absence of a dermal component predisposes cultured epidermal sheets to instability, contractibility, and makes them difficult to handle. In order to overcome these drawbacks, we developed recombined human/pig skin (RHPS) composed of human keratinocytes cultured on cell-free pig dermis. The original intention to prepare a permanent skin substitute composed of xenodermis and autologous epidermis was not achieved, but it has been proved that RHPS can serve as an effective, ready to use keratinocyte delivery system when applied 'upside-down', i.e. with epidermal cells facing the wound surface. The keratinocyte layer establishes a direct contact with the wound bed, while the dermal layer mechanically protects the wound. Twenty deep dermal burns were grafted with RHPS: 13 (65%) healed completely in 4-14 days, three (15%) healed partially and four (20%) did not heal. Of five full thickness burn wounds only one healed after repeated RHPS grafting within 18 days. Thirty-one (100%) donor sites treated with any of the three forms of RHPS, subconfluent, confluent meshed or confluent unmeshed, healed within 6-8 days compared with 14-18 days in control sites. Seven donor sites (100%) of immunodeficient patients with prolonged wound healing epithelialized in 7-10 days under RHPS compared with 32-90 days in areas treated with tulle gras and dry gauze.

Adolescent↗
PubMed2001

Acellular human dermis for facial soft tissue augmentation.

The search for safe, permanent, and natural-appearing materials for soft tissue augmentation is ongoing. This article discusses two autologous dermal preparations available in injectable forms that do not cause cyst formation and its associated problems.

Bioprosthesis↗
PubMed2002

Naturally occurring scaffolds for soft tissue repair and regeneration.

Cell growth supports (i.e., scaffolds) that provide a conducive environment for normal cellular growth, differentiation, and angiogenesis are important components of tissue engineered grafts because rapid integration with the host is essential for long-term graft viability. While many of these scaffold materials are synthetic biodegradable polymers, others are naturally derived from mammalian tissue sources. Naturally occurring scaffold materials include small intestinal submucosa, acellular dermis, amniotic membrane tissue, cadaveric fascia, and the bladder acellular matrix graft. Upon implantation, these materials elicit a host-tissue response that initiates angiogenesis, encourages tissue deposition and culminates in restoration of structure and function specific to the grafted site. The sources, the methods of procurement and processing, and the effects of these naturally occurring materials on angiogenesis and tissue deposition are reviewed.

Animals↗