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

A Histological and Clinical Study of MatriDerm® Use in Burn Reconstruction

Dermal substitutes are well established in the reconstructive ladder. MatriDerm® (Dr. Otto Suwelack Skin & Health Care AG, Billerbeck, Germany) is a single-layer dermal substitute composed of a bovine collagen (type I, III, and V) and elastin hydrolysate, that allows for immediate split-thickness skin grafting (SSG). The aim of this study was to histologically characterize the integration of MatriDerm® when used during burns surgery reconstruction. Eight subjects with nine burn scars and one acute burn wound underwent reconstruction with MatriDerm® and an immediate SSG. MatriDerm® integration and skin graft take were assessed with serial biopsies performed at weeks 1, 2, 3, and 4 and months 2, 3, 6, 9, and 12. Biopsies were assessed with standard special stains and immunohistochemistry, and representative slides were imaged with a transmission electron microscope. Patient satisfaction and clinical scar outcome were assessed with the Vancouver Scar Scale and a patient questionnaire. Histological analysis showed similar stages of wound healing as shown in other dermal templates but on a different timescale. There is early evidence of vascularization and an inflammatory infiltrate in the first 2 weeks. MatriDerm® is resorbed earlier than other dermal substitutes, with evidence of resorption at week 3, to be completely replaced by a neodermis at 2 months. The use of MatriDerm® in reconstruction with immediate skin grafting is supported histologically with early evidence of vascularization to support an epidermal autograft. Future histological studies may help further characterize the ideal dermal substitute.

Syndactyly release with the use of the Pelnac™ artificial dermal substitute without skin grafting

We present our results of one-stage resurfacing following syndactyly release with the Pelnac™ artificial dermal substitute. From 2016 to 2020, raw areas after digit release were restored with an artificial dermal substitute in 145 webs from 62 patients (average age, 33.1 months) including 65 simple incomplete web spaces, 29 simple complete web spaces, 20 complex complete web spaces, and 31 complex complicated web spaces. Fourteen patients were syndromic. The average follow-up period was 33.4 months (range, 7-55 months). Postoperative outcomes assessed as according to the Vancouver scar scale (0-14) averaged 1.8 (range, 0-11) and web creep score (0-5) averaged 0.7 (range, 0-4). Patient- and family-provided visual analog scale scores averaged 1.1 (range, 0-10) for appearance. In conclusion, the Pelnac™ artificial dermal substitute is a minimally invasive, simple, and effective option for one-stage resurfacing of defects in syndactyly release.

Superficial Circumflex Iliac Artery Perforator Flap with Bilobed Design for the Donor Defect after Wrap-Around Flap Transfer Reconstruction

OBJECTIVE

The repair of great toe donor site defect after wrap-around flap transfer is still controversial. The bilobed superficial circumflex iliac artery perforator (SCIP) flap can improve the aesthetics of the great toe while maintaining its function. Thus, this study aimed to report our experience in the reconstruction of big toe donor site defects with the bilobed SCIP flap and describe the clinical outcomes.

METHODS

This study was a retrospective trial. From May 2017 to May 2020, 13 patients with the great toe donor site defect after wrap-around flap transfer were included in this study. The average age of the patients was 44 years (range, 23-60 years). All patients received free bilobed SCIP flaps to reconstruct the donor site defect of the great toe. Relevant clinical features were recorded preoperatively. The thickness and design of the SCIP flap and the harvesting layer of the flap were measured during the operation. The survival rate of flaps and skin grafts and the incidence of infection were recorded after operation. At follow-up, donor site complications and postoperative outcomes were evaluated.

RESULTS

In all cases, the SCIP flap covering the donor site of the great toe survived. All patients were followed up for 24-40 months (mean, 30.5 months). The average thickness of the SCIP flap was 0.38cm. All SCIP flaps were harvested from the superficial fascial layer except for three obese patients. The thin SCIP flap had a bilobed design with no further defatting procedures. Postoperatively, the great toe-nail flap donor site regained its original appearance without bloating or flap necrosis. There was a hidden linear scar in the groin donor site, which did not affect hip joint movement. All patients were satisfied with the aesthetics of the surgical site.

CONCLUSION

The SCIP flap with bilobed design for repairing the donor defect of the great toe after wrap-around flap transfer is a kind of surgical method with excellent contour, meeting the requirements of function and aesthetics.

Development of gelatin hydrogel nonwoven fabrics (Genocel®) as a novel skin substitute in murine skin defects

Introduction

Genocel is an emerging material, used in cell culture, with high mechanical strength and good cytocompatibility. Based on these characteristics, Genocel is considered a promising skin substitute for wound healing. In this study, we explored the possibility of using Genocel as a skin substitute for murine skin defects and compared it with a conventional skin substitute.

Methods

Sheets of Genocel and Pelnac were applied to skin defects created on the backs of mice. On days 7, 14, and 21, the remaining wound area was evaluated and specimens were harvested for HE, Azan, anti-CD31, CD68, and CD163 staining to assess neoepithelialization, granulation tissue, capillary formation, and macrophage infiltration.

Results

No significant differences in the wound area or neoepithelium length were observed between groups. The number of newly formed capillaries in the Genocel group was significantly higher than that in the Pelnac group on day 7 (p < 0.05). In contrast, granulation tissue formation in the Pelnac group was greater than that in the Genocel group on day 14 (p < 0.05). Regarding macrophage infiltration, the pan-macrophage number, M2 macrophage number, and M2 ratio in the Pelnac group were higher than those in the Genocel group on day 14 (p < 0.05). In other aspects, the two materials displayed comparable behavior.

Conclusions

Genocel can be used as a skin substitute equivalent to the conventional one. In addition, Genocel accelerated capillary formation, which is more appropriate than conventional treatments for chronic skin ulcers, such as diabetic ulcers.

•

Gelatin hydrogel nonwoven fabrics, Genocel was used for the first time as a skin substitute for murine skin defects.

•

Genocel displayed comparable behavior with Pelnac and accelerated capillary formation in the early phase.

•

However, the Pelnac group produced more granulation tissue and more macrophages than the Genocel group on day 14.

Skin grafting treatment of adolescent lower limb avulsion injury

Background

Under the influence of various factors, the number of lower extremity avulsion injuries in adolescents is increasing year by year. The main modality of treatment is skin grafting. There are many types of skin grafting. Although many studies on skin grafting after avulsion injuries have been published in the past few decades, there are differences in the treatment options for adolescents with post avulsion injuries.

Main body

Thorough debridement and appropriate skin grafts are essential for the surgical management of avulsion injuries for optimal prognosis. In the acquisition of grafts, progress has been made in equipment for how to obtain different depths of skin. The severity of the avulsion injury varies among patients on admission, and therefore the manner and type of skin grafting will vary. Especially in adolescents, graft survival and functional recovery are of great concern to both patients and physicians. Therefore, many efforts have been made to improve survival rate and activity.

Conclusion

This review summarizes the principles of treatment of avulsion injuries, the historical development of skin grafts, and the selection of skin grafts, hoping to be helpful for future research.

Novel application of absorbable gelatine sponge combined with polyurethane film for dermal reconstruction of wounds with bone or tendon exposure

Trauma, burns, and diabetes result in nonhealing wounds that can cause bone or tendon exposure, a significant health threat. The use of an artificial regeneration template combined with skin grafting as an alternative method to highly invasive flap surgery has been shown to be an effective way to cover full-thickness skin defects with bone or tendon exposure for both functional and aesthetic recovery. However, artificial regeneration templates, such as Pelnac, are overwhelmingly expensive, limiting their clinical use. Here, we demonstrate for the first time that polyurethane film combined with absorbable gelatine sponge, affordable materials widely used for haemostasis, are effective for dermal reconstruction in wounds with bone or tendon exposure. The absorbable gelatine sponge combined with polyurethane film was applied to eight patients, all resulting in adequate granulation that fully covered the exposed bone or tendon. The outcome of absorbable gelatine sponge combined with polyurethane film application indicates that this approach is a potential novel and cost-effective dermal reconstruction strategy for the treatment of severe wounds with bone or tendon exposure.

Fabrication of SA/Gel/C scaffold with 3D bioprinting to generate micro-nano porosity structure for skin wound healing: a detailed animal in vivo study

Bioprinting has exhibited remarkable promises for the fabrication of functional skin substitutes. However, there are some significant challenges for the treatment of full-thickness skin defects in clinical practice. It is necessary to determine bioinks with suitable mechanical properties and desirable biocompatibilities. Additionally, the key for printing skin is to design the skin structure optimally, enabling the function of the skin. In this study, the full-thickness skin scaffolds were prepared with a gradient pore structure constructing the dense layer, epidermis, and dermis by different ratios of bioinks. We hypothesized that the dense layer protects the wound surface and maintains a moist environment on the wound surface. By developing a suitable hydrogel bioink formulation (sodium alginate/gelatin/collagen), to simulate the physiological structure of the skin via 3D printing, the proportion of hydrogels was optimized corresponding to each layer. These results reveal that the scaffold has interconnected macroscopic channels, and sodium alginate/gelatin/collagen scaffolds accelerated wound healing, reduced skin wound contraction, and re-epithelialization in vivo. It is expected to provide a rapid and economical production method of skin scaffolds for future clinical applications.

Use of single-layer artificial dermal template in patients with trauma and burns

Objective:

Artificial dermal templates (ADTs), were designed initially to provide extracellular matrix and skin substitute for extensive burn injuries. Use of ADTs in a variety of other indications, has also been described in the literature. In this study, we describe our experience of using ADTs for different indications in burn contractures and wound coverage.

Method:

In this retrospective study, patients requiring burn scar contracture release, permanent wound coverage for acute traumatic wounds and temporary wound coverage to prepare for complex reconstructions, and where the ADT Pelnac (Gunze Ltd., Japan) was applied, were evaluated. Data regarding patient sex, age, type and location of injury, comorbidities, operations and complications were recorded.

Results:

A total of 24 patients were included in the study, of whom 12 patients were operated on for burn contractures. ADTs were used with split-thickness skin grafts (STSGs) or Z-plasties in a single-stage procedure. In six patients, ADT and STSGs were used to cover defects with exposed bone or tendon. Of the patients, six had their wounds covered temporarily while they were stabilised for complex reconstructions or were awaiting definitive histopathological results. Revisional surgeries due to graft failures or insufficient contracture releases were required by 12 patients. All temporary wound coverage patients had successful flap reconstructions after stabilisation of their general status, had tumour-free margins in the histopathological examination, and no necrosis or infection was seen on follow-up.

Conclusion:

In this study, ADTs had positive effects on selected patients, but comprehensive and comparative clinical studies are needed for different indications to choose between these templates.

Analysis of the therapeutic effect of artificial leather embedding combined with fascial sleeve flap transplantation on chronic wounds of lower limbs with bone and plate exposure

BACKGROUND

After severe trauma of lower limbs, bone, tendon or plate graft exposure is common. The traditional repair method is to use a variety of skin flap transplantation to cover the exposed part, but the wound often can not heal after operation, or the wound is cracked, ulcer, sinus, bone and steel plate are exposed again after wound healing. The reason for this result is that when the flap is covered, the space around the bone plate is not well closed, forming a dead cavity, blood and exudate accumulation, hematoma formation or infection, and finally the wound ruptures again. In addition, due to the swelling and contracture of the flap after operation, the suture tension between the flap and the receiving area becomes larger, the skin becomes thinner and broken, and then the wound is formed. In order to solve the above problems, we carried out the study of artificial true skin embedding combined with fascial sleeve flap transplantation in the treatment of chronic bone plate exposed wounds of lower limbs.

METHODS

In this paper, 11 cases of chronic wounds with bone exposure and skin necrosis after steel plate implantation were selected. First stage is the wound bed preparation including primary wound expansion, removal of necrotic tissue and incision of sinus wall, removal of deep necrotic bone and fibrotic scarred skin on the outer wall of steel plate to normal tissue on the outer edge of the wound, removal of precipitated peptone and purulent fur in the hole, periphery and bone space of the steel plate, and removal of tendon tissue with basal necrosis and disintegration of the wound. After vacuum sealing drainage (VSD) 1-2 weeks, the peritraumatic basal granulation tissue grew well and there was no necrotic tissue in the wound. In the second stage, the exposed bone was covered with artificial dermis, the steel plate hole or the periphery and the basal space were filled, and the exposed steel plate was completely embedded, and then the fascia sleeve flap was transplanted to cover the wound. The sural neurovascular flap was performed in nine cases and the lateral superior malleolar artery perforator flap in two case.

RESULTS

The flap survived well in all 11 cases. During the follow-up of 6 months to the removal of the plate, there was no case of rupture, exposure and sinus formation.

CONCLUSIONS

Artificial dermal covering combined with fascial sleeve flap transplantation can effectively avoid wound dehiscence or sinus formation caused by foreign body retention, infection and flap contracture. It has good effect in repairing chronic wounds with bone plate exposure after severe trauma of lower limbs.

Clinical Application of Artificial Dermis and Autologous Skin in Repairing Skin and Soft Tissue Defects of Hands and Feet with Bone Exposure Injuries

Patients with skin and soft tissue defects are very common. Mild trauma often causes mild skin damage, while severe injuries are often accompanied by bone and tendon exposure, which brings great pain to patients. For the defect of skin and soft tissue, the traditional treatment methods are mostly medium or full-thickness skin or skin flap transplantation. These methods are effective in wound repair, but there are still many problems. In recent years, with the improvement of tissue engineering technology, the use of artificial skin to repair various skin wounds is gradually becoming clinical, and the key technology of skin tissue engineering lies in the development of dermal substitutes. The appearance of artificial dermis not only solves the shortage of autologous skin source but also makes the operation simple and easy. The purpose of this study was to investigate the clinical effect of artificial dermis combined with autologous skin grafts in repairing hand and foot skin and soft tissue defects with bone exposure. The results show that the use of artificial dermis combined with autogenous blade thick skin to treat patients with hand and foot soft tissue injury with bone exposure has a good clinical effect, and the skin is alive and has fewer complications, which is worthy of promotion.

Engineering Bioactive Scaffolds for Skin Regeneration

Large skin wounds pose a major clinical challenge. Scarcity of donor site and postsurgical scarring contribute to the incomplete or partial loss of function and aesthetic concerns in skin wound patients. Currently, a wide variety of skin grafts are being applied in clinical settings. Scaffolds are used to overcome the issues related to the misaligned architecture of the repaired skin tissues. The current review summarizes the contribution of biomaterials to wound healing and skin regeneration and addresses the existing limitations in skin grafting. Then, the clinically approved biologic and synthetic skin substitutes are extensively reviewed. Next, the techniques for modification of skin grafts aiming for enhanced tissue regeneration are outlined, and a summary of different growth factor delivery systems using biomaterials is presented. Considering the significant progress in biomaterial science and manufacturing technologies, the idea of biomaterial-based skin grafts with the ability for scarless wound healing and reconstructing full skin organ is more achievable than ever.

External administration of moon jellyfish collagen solution accelerates physiological wound healing and improves delayed wound closure in diabetic model mice

Introduction

Artificial dermis is an effective therapeutic method for full-thickness dermal defects. However, the currently available artificial dermis made of porcine or bovine type I collagen has several limitations such as incomplete epithelialization and delayed migration of fibrogenic and angiogenic cells into the graft. We previously developed a composite dermal graft containing a mixture of moon jellyfish collagen and porcine type I collagen, and reported its stimulatory effect on both the re-epithelialization of the epidermis and the migration of fibrogenic and angiogenic cells into the graft. In the present study, we examined whether the same effect was observed by administering jellyfish collagen solution externally onto an artificial dermal graft made of bovine type I collagen.

Methods

We used a 6 mm full-thickness wound defect model. Moon jellyfish collagen was prepared as a concentrated 0.5% solution and dripped externally onto a transplanted artificial dermal graft made of bovine type I collagen. Wound repair and long-term dermal tissue remodeling were compared between mice administered jellyfish collagen solution on the bovine collagen graft and those transplanted with a composite dermal graft containing the same amounts of jellyfish and bovine collagens. The stimulatory effect of jellyfish collagen solution was also evaluated using diabetic dB/dB mice.

Results

External administration of jellyfish collagen solution onto the bovine collagen graft significantly accelerated wound closure compared to control saline. It also decreased the number of inflammatory cells infiltrating the wound and suppressed absorption of the transplanted graft, as well as reduced subsequent scar formation. Furthermore, external administration of jellyfish collagen solution onto the bovine collagen graft improved the delayed wound healing in diabetic model mice, and this effect was superior to that of the currently used basic fibroblast growth factor.

Conclusions

External administration of moon jellyfish collagen solution onto a bovine collagen graft significantly accelerated physiological wound healing and prevented excessive scar formation. It also improved wound closure in diabetic model mice, confirming its therapeutic application for intractable skin ulcers caused by impaired wound healing.

•

Impaired wound healing is frequently observed in elderly and diabetic patients.

•

Moon jellyfish collagen accelerates wound closure after full-thickness dermal defect in mice.

•

Jellyfish collagen used as an external medicine stimulates the elongation of regenerating epithelial cells.

•

Externally applied jellyfish collagen improves wound healing in diabetic model mice.

Malignant phyllodes tumor of the breast with rapid progression: a case report

BACKGROUND

Malignant phyllodes tumors (PTs) of the breast occur infrequently and are difficult to treat with adjuvant therapy. Here, we present a case of a female patient with a huge malignant PT with rapid progression in a short period.

CASE PRESENTATION

A 44-year-old woman presented to our hospital with a rapid growth mass in her right breast, measuring 20 cm. She was initially diagnosed as having a borderline phyllodes tumor by core needle biopsy and underwent total mastectomy and artificial dermis was grafted, 20 days later, latissimus dorsi muscle flap and free skin grafting were performed. Two courses of doxorubicin-ifosfamide therapy were administered because of recurrence, but the patient died 4 months after the mastectomy.

CONCLUSIONS

A standard therapeutic strategy for malignant PTs is needed in urgently to reduce the risk of tumor recurrence.

Utility of a New Artificial Dermis as a Successful Tool in Face and Scalp Reconstruction for Skin Cancer: Analysis of the Efficacy, Safety, and Aesthetic Outcomes

Radical ablative surgery is the gold standard treatment of head skin cancer. The authors expose their experience with a new artificial dermis (Pelnac®), analyzing retrospectively the overall morbidity and aesthetic outcomes. 16 consecutive patients underwent two surgical procedures under local anesthesia. The first involved the tumor removal and application of the ADM. In the second, the exposed tissue was covered with a split-thickness skin graft. On follow-up (6 months), tumor recurrences, quality of scars (using the Vancouver Scar Scale), and patient reported outcomes (using FACE-Q Skin Cancer Module) were evaluated. 10 were males and 6 females, with a mean age of 73 years (61-89). The follow-up ranged from 12 to 48 months (mean: 30). The sites of skin tumor were scalp (12 cases), forehead (2), cheek (1), and zygomatic area (1). Nine patients underwent previous local surgery; two received radiotherapy. The average length of hospital stay was 3.2 days. The mean surface area of the defect was 59.15 cm² (16.9-89.5). In three cases, the surgical bed was bone without periosteum. The malignant tumors excised were basal cell carcinoma (68.75%), squamous cell carcinoma (18.75%), malignant melanoma (6.25%), and sarcoma (6.25%). The mean operating time was 41 minutes for the first operation (25-55) and 34 for the second (25-48). No significant problems were observed and 15 patients (93.75%) had 100 percent intake of graft. The mean time of healing was 39 days (32-45). At 6 months post-op, no tumor recurrence. Satisfactory cosmetic and functional results were obtained in all patients as shown by the VSS Scale and FACEQ skin cancer module mean scores. We believe that the artificial dermis is a reliable alternative to flaps and should be considered an excellent option in head reconstruction for skin cancer, especially in critical patients (old, with large and deep defects, with recurrent tumors, required radiotherapy).

Infectious Complications Associated with the Use of Integra: A Systematic Review of the Literature

Dermal regeneration templates such as Integra are effective reconstructive biomaterials used in a variety of soft-tissue defects. Fully understanding the complications associated with their use is paramount to improve outcomes and maximize patient safety. In this study, our purpose is to perform a comprehensive literature review to assess the previously reported infectious complications linked to Integra-based wound closure.

Pelnac® Artificial Dermis Assisted by VSD for Treatment of Complex Wound with Bone/Tendon Exposed at the Foot and Ankle, A Prospective Study

Purpose: This study aims to assess the efficacy and safety of Pelnac dermal regeneration template assisted by vacuum sealing drainage (VSD) and a split-thickness skin graft to cover the large skin and soft-tissue defects at foot and ankle. Methods: This study began from March 2013, up to February 2017. A total of 16 patients met the inclusion and exclusion criteria and were included. For every patient, 2 separate operations were performed, the first being thorough debridement of necrotic tissues immediate coverage of VSD at continuous negative pressure suction, and the second being the autologous split-thickness skin graft. At each follow-up, relevant data were documented. Results: The average follow-up was 16.5 months (range, 12 to 42 months). No infections, hematoma, or seroma were observed. 13 out of 16 patients had a complete skin graft "take" (100%). Patients' satisfaction of esthetic appearance was 76.5 ± 5.2/100. The VSS value was 2.2 ± 2.1, representing a good result. Regarding the sensory recovery, the response "normal or near normal" could be obtained in 14/16 patients. Mean AROM for extension/flexion of the ankle was 48.5 ± 4.8° (range 35-62°), and 93.7% (15/16) of patient could obtain a satisfying functional result. Conclusions: Our report indicated Pelnac provided an effective method for management of complex wounds with underlying bone or tendons exposed.

The use of dermal regeneration template for treatment of complex wound with bone/tendon exposed at the forearm and hand, a prospective cohort study

The purpose of this study was to assess the efficacy and safety of Pelnac and split-thickness skin graft for management of complex wound with underlying bone/tendon exposure at forearm and hand.This is a prospective study, beginning from March 2013 up to May 2017. There were 13 patients, with age of 31.2 years. All of them underwent the staged Pelnac and split-thickness skin graft to manage the complex wound with bone/tendon. Postoperatively, scheduled follow-up was conducted.The average follow-up was 15 months. There were no infections, wound necrosis, hematoma, or seroma during the phase when Pelnac was applied. There was 100% "take" of the Pelnac in 12/13 patients. In 11 patients, there was complete skin graft "take". Patients' satisfaction for the esthetic appearance of the grafted area was 75.0 ± 8.5/100. The VSS value was 2.9 ± 2.5. Regarding the sensory recovery, the response of "normal or near normal" could be obtained in 7/13 patients, "slight loss" in 5 patients and "significant loss" in 1 case. The average DASH score was 27.2 ± 18.5, and most patients (12/13) could obtain an acceptable ability to perform the daily activities.Pelnac dermal template is a favorable alternative to flap reconstruction in the treatment of complex wound with underlying tissues exposure.

The significance of collagen dressings in wound management: a review

Clinical experience and research has improved our understanding of wound healing which, in turn, has enabled health professionals to aid wound healing and manufacturers to develop modern wound dressings. The significant role of collagen in wound healing has led to the development of numerous products on the basis of this biological material. The main focus of this review is to provide a critical appraisal of publications about collagen and acellular collagen dressings with a fleece-like or spongy structure. It is intended for clinicians and researchers, and aims to keep them up-to-date in the complex field of interactive, collagen-based wound dressings, including their manufacture, combination possibilities, mechanisms of action, performance in the promotion of wound healing and indications. Despite the small number of clinical studies, the importance of acellular collagen dressings with a fleece- or sponge-like structure is likely to increase in the future. As there is no ideal wound dressing, the knowledge attained is meant to support health professionals in selecting the right product, and pave the way for new applications and clinical studies.

Bioengineered smart trilayer skin tissue substitute for efficient deep wound healing

Skin substitutes for deep wound healing require meticulous designing and fabrication to ensure proper structural and functional regeneration of the tissue. Range of physical and mechanical properties conducive for regeneration of different layers of skin is a prerequisite of an ideal scaffold. However, single or bilayer substitutes, lacking this feature, fail to heal full thickness wound. Complete scar free regeneration of skin is still a big challenge. This study reports fabrication of a trilayer scaffold, from biodegradable polymers that can provide the right ambience for simultaneous regeneration of all the three layers of skin. The scaffold was developed through optimization of different fabrication techniques, namely, casting, electrospinning and lyophilisation, for obtaining a tailored trilayer structure. It has mechanical strength similar to skin layers, can maintain a porosity-gradient and provides microenvironments suitable for simultaneous regeneration of epidermis, dermis and hypodermis. A co-culture model, of keratinocytes and dermal fibroblasts, confirms the efficiency of the scaffold in supporting proliferation and differentiation of different types of cells, into organized tissue. The scaffold showed improved and expedited wound healing in-vivo. Taken together, these compelling evidences successfully established the engineered trilayer scaffold as a promising template for skin tissue regeneration in case of deep wound.

One-step approach for full-thickness skin defect reconstruction in rats using minced split-thickness skin grafts with Pelnac overlay

Background

Split-thickness skin grafting is the current gold standard for the treatment of traumatic skin loss. However, for patients with extensive burns, split-thickness skin grafting is limited by donor skin availability. Grafting split-thickness skin minced into micrografts increases the expansion ratio but may reduce wound repair quality. Dermal substitutes such as Pelnac can enhance the healing of full-thickness skin wounds, but their application currently requires two surgeries. The present study investigated whether it is possible to repair full-thickness skin defects and improve wound healing quality in a single surgery using Pelnac as an overlay of minced split-thickness skin grafts in a rat model.

Methods

A full-thickness skin defect model was established using male Sprague-Dawley rats of 10 weeks old. The animals were randomly divided into control and experimental groups in which Vaseline gauze and Pelnac, respectively, were overlaid on minced split-thickness skin grafts to repair the defects. Wound healing rate and quality were compared between the two groups. For better illustration of the quality of wound healing, some results were compared with those obtained for normal skin of rats.

Results

We found that using Pelnac as an overlay for minced split-thickness skin grafts accelerated wound closure and stimulated cell proliferation and tissue angiogenesis. In addition, this approach enhanced collagen synthesis and increased the formation of basement membrane and dermis as well as the expression of growth factors related to wound healing while reducing scar formation.

Conclusions

Using minced split-thickness skin grafts overlaid with Pelnac enables the reconstruction of full-thickness skin defects in a single step and can increase the healing rate while improving the quality of wound healing.

Treatment of Large Scars in Children Using Artificial Dermis and Scalp Skin Grafting

BACKGROUND AND OBJECTIVES

Large scars formed after burns injury can seriously hamper appearance and function in children. Surgical resection of scars and secondary skin or flap grafting often brings severe damages to donor sites, which may lead to physiological and psychological development disorders in children. Here, we introduce the use of artificial dermis and skin grafts from scalps to treat large scars in children to minimize the donor site morbidity.

METHODS

A retrospective char review was performed including 7 children with large scars between January 2016 and December 2017. First, the scars were resected, and artificial dermis was applied to the secondary wounds. Twelve days later, outer silicone membrane was removed. Another 2 days later, scalp skin grafts of 0.3 mm were transplanted to the wounds. Manchester Scar Scale and Visual Analog Scale were used to evaluate scar appearance before and after the treatment respectively. One special patient with extensive scars was treated twice at an interval of 1 year. The first therapy was performed with both conventional method of resection and skin grafting and the new method described above. In the second therapy, 4 samples were taken from 4 different sites-the normal skin, scars, the skin where artificial dermis and scalp skin grafting were performed, and the skin where only scalp skin grafting was performed. H-E staining, Masson staining, Aldehyde fuchsin staining, and scanning electron microscopy were used for histological observation.

RESULTS

All skin grafts survived well. The Manchester Scar Scale score of the graft area was significantly reduced (P < 0.01) after the treatment. Histological examination showed obviously better dermis arrangement where artificial dermis and scalp grafting was performed.

CONCLUSION

The therapy achieves better appearances and minimizes donor site morbidity. It is beneficial to physical and psychological development of children and provides an alternative to treat children with large scars.

A Perifascial Areolar Tissue Graft With Topical Administration of Basic Fibroblast Growth Factor for Treatment of Complex Wounds With Exposed Tendons and/or Bones

The management of wounds with tendon and/or bone exposure is challenging because of the insufficient blood supply to the wound bed. We describe our experience with 19 patients using a perifascial areolar tissue (PAT) graft with topical administration of basic fibroblast growth factor (bFGF) in the treatment of complex wounds with exposed tendons and/or bones in the extremities. Using a PAT graft is minimally invasive and technically easy, and the donor site is relatively preserved. However, PAT grafts for the treatment of a complex wound with large areas of exposed tendons and/or bones have sometimes failed to survive because of insufficient vascularization of the wound bed. Therefore, topical administration of bFGF, which promotes angiogenesis, was added to the graft. All grafts showed good graft survival and successfully covered the tendons and bones. Topical administration of bFGF accelerated vascularization in the PAT graft and facilitated wound healing by increasing the blood supply to the wound bed and achieved success with the PAT graft. In conclusion, using a PAT graft with topical administration of bFGF is a suitable option for the treatment of complex wounds with a large proportion of exposed tendons and/or bones. With minimal damage to the tissues near the wound, the PAT graft can be a useful option for limb salvage and could become a valuable tool for reconstructive surgeons.

FGF-2 combined with bilayer artificial dermis composed of collagen matrix prompts generation of fat pad in subcutis of mice

Fibroblast growth factor (FGF)-2 induces mitogenesis, angiogenesis and adipogenesis. In this study, the adipogenesis-inducing effects of FGF-2 combined with bilayer artificial dermis in mice were evaluated. FGF-2-impregnated bilayer artificial dermis composed of collagen matrix, PELNAC (Gunze Corp., Osaka, Japan) was implanted subcutaneously into the thoracic region of mice. At 1, 2, 3, and 4 weeks, samples were collected for H&E staining, von Willebrand factor immunostaining, and perilipin immunostaining to examine adipose tissue localization and angiogenesis. The collagen matrix-implanted group without the addition of FGF-2 was prepared as a control. At 2 weeks after the implantation of FGF-2 combined with dermal substitutes, adipocytes appeared in the collagen fibers. At 3–4 weeks, a fat pad was generated with neovascularization. The thickness of the fat pad had significantly increased at 2, 3, and 4 weeks. The remaining collagen was decreased by absorption over time. In the control group, no fat pad was newly formed. This study has identified a promising method to enhance adipogenic effects in the murine subcutis, representing a potential technique for soft tissue reconstruction.

Leprosy-associated Chronic Wound Management Using Biomaterials

Background:

Deformities and neuropathic chronic ulcers are the common features associated with leprosy-cured individuals that impact their quality of life and impair rehabilitation efforts. The challenging aspects for treatment of chronic wounds are the factors that inhibit healing. We reasoned that limited success of various therapeutic interventions could be due to the fact that leprosy-cured individual's physiology gets acclimatized to having a chronic wound that any therapeutic intervention is counterbalanced to maintain status quo at the wound site. Therefore, an alternative strategy would be to use biomaterials that gradually alter the wound site allowing the individual's physiology to participate in the healing process.

Aims:

Developing the human amnion (Amn)-derived biomaterial scaffolds and evaluating its use to heal chronic wounds in leprosy-cured but deformed persons (LCDPs).

Materials and Methods:

Using an enzymatic protocol, we have developed a rapid method to generate biomaterial scaffolds from discarded human Amn. A clinical trial on 26 LCDPs was performed with the biomaterial, and its wound-healing potential was then compared with LCDPs undergoing standard treatment procedure.

Results:

Biomaterial-based treatment of chronic wounds on LCDP displayed a higher efficiency in healing when compared to standard treatment.

Conclusions:

This study exemplifies that biomaterial-based treatment of leprosy-wounds offers an excellent affordable alternative for wound management. This study underlines the importance of involving both local wound environment and systemic effects for healing. In addition, we highlight wound healing as a necessity for successful rehabilitation and reintegration of leprosy-cured person into the society.

Combined effects of artificial dermis and vascular endothelial growth factor concentration gradient on wound healing in diabetic porcine model

Wounds in patients with diabetes mellitus are one of the most prevalent impaired wounds in the world. Vascular endothelial growth factor (VEGF) is one of the most important proangiogenic mediators. Artificial dermal (AD) such as Pelnac^® has been shown, in humans and animal models, a great therapeutic potential in full-thickness skin wounds. We attempt to promote the wound healing in diabetic porcine models through combined use of AD and constant concentration of VEGF or VEGF concentration gradient. We created full-thickness excisional wounds in diabetic animal models. Analyzed the healing process through images, histology and immunohistochemistry. Results show that the combination of AD and concentration gradient of VEGF could provide an appropriate angiogenesis, improve granulation formation, increase epithelization and maintain the VEGF levels of the wound bed. Eventually accelerate the direct healing of diabetic wounds or make good preparation for secondary skin graft.

Transplanted fibroblasts proliferate in host bronchial tissue and enhance bronchial anastomotic healing in a rodent model

INTRODUCTION

Healing of airway anastomoses after preoperative irradiation can be a significant clinical problem. The augmentation of bronchial anastomoses with a fibroblast-seeded human acellular dermis (hAD) was shown to be beneficial, although the underlying mechanism remained unclear. Therefore, in this study we investigated the fate of the fibroblasts transplanted to the scaffold covering the anastomosis.

MATERIAL AND METHODS

32 Fisher rats underwent surgical anastomosis of the left main bronchus. In a 2 × 2 factorial design, they were randomized to receive preoperative irradiation of 20 Gy and augmentation of the anastomosis with a fibroblast-seeded transplant. Fibroblasts from subcutaneous fat of Fischer-344 rat were transduced retrovirally with tdTomato for cell tracking. After 7 and 14 days, animals were sacrificed and cell concentration of transplanted and nontransplanted fibroblasts in the hAD as well as in the bronchial tissue was measured using RT-PCR.

RESULTS

Migration of transplanted fibroblasts from dermis to bronchus were demonstrated in both groups, irradiated and nonirradiated. In the irradiated groups, there was a cell count of 7 × 104 ± 1 × 104 tomato+-fibroblasts in the bronchial tissue at day 7, rising to 1 × 105 ± 1 × 104 on day 14 (p <0.0001). Tomato+-cell concentration in hAD increased from 6 × 103 ± 1 × 103 at day 7 to 6 × 104 ± 1 × 104 at day 14 (p <0.0001). In the nonirradiated groups, tomato+-cell concentration in bronchus was 4 × 103 ± 1 × 103 on day 7 and 4 × 103 ± 1 × 103 at day 14. In the hAD tomato+ cell concentration rising from 1 × 104 ± 1 × 103 at day 7 to 2 × 104 ± 3 × 103 cells at day 14 (p = 0.0028).

CONCLUSIONS

Transplanted fibroblasts in the irradiated groups proliferate and migrate into the irradiated host bronchial tissue, but not in the nonirradiated groups.

RNA Interference and BMP-2 Stimulation Allows Equine Chondrocytes Redifferentiation in 3D-Hypoxia Cell Culture Model: Application for Matrix-Induced Autologous Chondrocyte Implantation

As in humans, osteoarthritis (OA) causes considerable economic loss to the equine industry. New hopes for cartilage repair have emerged with the matrix-associated autologous chondrocyte implantation (MACI). Nevertheless, its limitation is due to the dedifferentiation occurring during the chondrocyte amplification phase, leading to the loss of its capacity to produce a hyaline extracellular matrix (ECM). To enhance the MACI therapy efficiency, we have developed a strategy for chondrocyte redifferentiation, and demonstrated its feasibility in the equine model. Thus, to mimic the cartilage microenvironment, the equine dedifferentiated chondrocytes were cultured in type I/III collagen sponges for 7 days under hypoxia in the presence of BMP-2. In addition, chondrocytes were transfected by siRNA targeting Col1a1 and Htra1 mRNAs, which are overexpressed during dedifferentiation and OA. To investigate the quality of the neo-synthesized ECM, specific and atypical cartilage markers were evaluated by RT-qPCR and Western blot. Our results show that the combination of 3D hypoxia cell culture, BMP-2 (Bone morphogenetic protein-2), and RNA interference, increases the chondrocytes functional indexes (Col2a1/Col1a1, Acan/Col1a1), leading to an effective chondrocyte redifferentiation. These data represent a proof of concept for this process of application, in vitro, in the equine model, and will lead to the improvement of the MACI efficiency for cartilage tissue engineering therapy in preclinical/clinical trials, both in equine and human medicine.

Phenotypic Screening Identifies Synergistically Acting Natural Product Enhancing the Performance of Biomaterial Based Wound Healing

The potential of multifunctional wound heal biomaterial relies on the optimal content of therapeutic constituents as well as the desirable physical, chemical, and biological properties to accelerate the healing process. Formulating biomaterials such as amnion or collagen based scaffolds with natural products offer an affordable strategy to develop dressing material with high efficiency in healing wounds. Using image based phenotyping and quantification, we screened natural product derived bioactive compounds for modulators of types I and III collagen production from human foreskin derived fibroblast cells. The identified hit was then formulated with amnion to develop a biomaterial, and its biophysical properties, in vitro and in vivo effects were characterized. In addition, we performed functional profiling analyses by PCR array to understand the effect of individual components of these materials on various genes such as inflammatory mediators including chemokines and cytokines, growth factors, fibroblast stimulating markers for collagen secretion, matrix metalloproteinases, etc., associated with wound healing. FACS based cell cycle analyses were carried out to evaluate the potential of biomaterials for induction of proliferation of fibroblasts. Western blot analyses was done to examine the effect of biomaterial on collagen synthesis by cells and compared to cells grown in the presence of growth factors. This work demonstrated an uncomplicated way of identifying components that synergistically promote healing. Besides, we demonstrated that modulating local wound environment using biomaterials with bioactive compounds could enhance healing. This study finds that the developed biomaterials offer immense scope for healing wounds by means of their skin regenerative features such as anti-inflammatory, fibroblast stimulation for collagen secretion as well as inhibition of enzymes and markers impeding the healing, hydrodynamic properties complemented with other features including non-toxicity, biocompatibility, and safety.

The use of artificial dermis for corrective surgery on burn scars

Background

Hypertrophic scarring from burn injuries on large skin areas is of great concern for both patients and attending physicians because of significant functional and cosmetic impairment. Surgery for scar corrections is challenging because of limitations on the availability of normal tissue. An alternative method for scar correction using artificial dermis is now possible. Artificial dermis can be used in the reconstruction of scars, burn injuries on large skin areas and in patients who do not have sufficient donor sites for skin grafts after scar excisions.

Objective

To report the efficacy of artificial dermis on a 20 years old Thai man with severe scar contracture from burn injuries.

Method

An open-label case study, the severe contracture case underwent scar excision and was applied with artificial dermis.

Result

A 20-year-old man had severe scar contractures on his left arm, forearm, and elbow, and a shearing wound with a scar at his left elbow. Total scar excision was done on his left arm, forearm, elbow, and hand, and then followed by application of artificial dermis on to the wounds. After 2 weeks, neodermis formation was observed, after which an ultrathin split thickness skin graft was applied to the wounds. One month after sugery, the patient could extend his left elbow fully and the cosmetic result is satisfactory.

Conclusion

Use of artificial dermis should be a new alternative modality in improving our strategy in correcting scar issues from burn injuries, especially on large burn scar areas with limited donor sites for skin grafts.

Future Prospects for Scaffolding Methods and Biomaterials in Skin Tissue Engineering: A Review

Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL), and poly-ethylene-glycol (PEG), etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts.

Collagen Hydrogel Scaffold and Fibroblast Growth Factor-2 Accelerate Periodontal Healing of Class II Furcation Defects in Dog

OBJECTIVE

Collagen hydrogel scaffold exhibits bio-safe properties and facilitates periodontal wound healing. However, regenerated tissue volume is insufficient. Fibroblast growth factor-2 (FGF2) up-regulates cell behaviors and subsequent wound healing. We evaluated whether periodontal wound healing is promoted by application of collagen hydrogel scaffold in combination with FGF2 in furcation defects in beagle dogs.

METHODS

Collagen hydrogel was fabricated from bovine type I collagen with an ascorbate-copper ion cross-linking system. Collagen hydrogel was mingled with FGF2 and injected into sponge-form collagen. Subsequently, FGF2 (50 µg)/collagen hydrogel scaffold and collagen hydrogel scaffold alone were implanted into class II furcation defects in dogs. In addition, no implantation was performed as a control. Histometric parameters were assessed at 10 days and 4 weeks after surgery.

RESULT

FGF2 application to scaffold promoted considerable cell and tissue ingrowth containing numerous cells and blood vessel-like structure at day 10. At 4 weeks, reconstruction of alveolar bone was stimulated by implantation of scaffold loaded with FGF2. Furthermore, periodontal attachment, consisting of cementum-like tissue, periodontal ligament-like tissue and Sharpey's fibers, was also repaired, indicating that FGF2-loaded scaffold guided self-assembly and then re-established the function of periodontal organs. Aberrant healing, such as ankylosis and root resorption, was not observed.

CONCLUSION

FGF2-loaded collagen hydrogel scaffold possessed excellent biocompatibility and strongly promoted periodontal tissue engineering, including periodontal attachment re-organization.

Review of Bionanocomposite Coating Films and Their Applications

The properties of a composite material depend on its constituent materials such as natural biopolymers or synthetic biodegradable polymers and inorganic or organic nanomaterials or nano-scale minerals. The significance of bio-based and synthetic polymers and their drawbacks on coating film application is currently being discussed in research papers and articles. Properties and applications vary for each novel synthetic bio-based material, and a number of such materials have been fabricated in recent years. This review provides an in-depth discussion on the properties and applications of biopolymer-based nanocomposite coating films. Recent works and articles are cited in this paper. These citations are ubiquitous in the development of novel bionanocomposites and their applications.

Janus films with stretchable and waterproof properties for wound care and drug delivery applications

Janus PDMS films with porous/nonporous structures are fabricated for wound care. The film has good stretchability, waterproof and breathable surfaces and non-stick properties, which enhance its performance compared to traditional wound bandages.

The availability of perifascial areolar tissue graft for deep cutaneous ulcer coverage

Soft tissue defects or skin ulcers associated with tendon or bone exposure located distally on the extremities are always difficult to treat. The introduction of the vacuum-assisted closure (VAC) and dermal templates has led to major changes in ulcer treatment strategies. However, it is necessary to find an alternative method to treat these defects when VAC is not available. Perifascial areolar tissue (PAT) is the loose connective tissue on the deep fascia that could be a candidate for repairing soft tissue defects or skin ulcers. Grafting PAT on the exposed bone or tendon, including a wide coverage of well-vascularized tissue surrounding the granulation tissue, can prepare the wound to be subsequently closed by a skin graft. In this study, the PAT was used in various situations and its optimal usage and outcomes were evaluated. A total of 13 PAT grafts were performed and were especially useful for covering narrow ulcers with narrow tendon exposure and filling fistula areas. In comparison to other cases, covering the exposed cortical bone ulcers seemed to be more difficult to perform. However, an option for these ulcers could be the exposure of bone marrow and usage of intraosseous blood flow. It was also possible for the simultaneous engraftment of PAT and skin in narrow areas and could be an alternative in cases of small concave ulcers or fistulae. The PAT graft is a simple and minimally invasive procedure that can be a good alternative when VAC is not available.

In vivo Quantification of the Effects of Radiation and Presence of Hair Follicle Pores on the Proliferation of Fibroblasts in an Acellular Human Dermis in a Dorsal Skinfold Chamber: Relevance for Tissue Reconstruction following Neoadjuvant Therapy

INTRODUCTION

In neoadjuvant therapy, irradiation has a deleterious effect on neoangiogenesis. The aim of this study was to examine the post-implantation effects of neoadjuvant irradiation on the survival and proliferation of autologous cells seeded onto an acellular human dermis (hAD; Epiflex). Additionally, we examined the influence of dermal hair follicle pores on viability and proliferation. We used dorsal skinfold chambers implanted in rats and in-situ microscopy to quantify cell numbers over 9 days.

METHODS

24 rats received a skinfold chamber and were divided into 2 main groups; irradiated and unirradiated. In the irradiated groups 20Gy were applied epicutaneously at the dorsum. Epiflex pieces were cut to size 5x5mm such that each piece had either one or more visible hair follicle pores, or no such visible pores. Fibroblasts were transduced lentiviral with a fluorescent protein for cell tracking. Matrices were seeded statically with 2.5x104 fluorescent fibroblasts and implanted into the chambers. In each of the two main groups, half of the rats received Epiflex with hair follicle pores and half received Epiflex without pores. Scaffolds were examined in-situ at 0, 3, 6 and 9 days after transplantation. Visible cells on the surface were quantified using ImageJ.

RESULTS

In all groups cell numbers were decreased on day 3. A treatment-dependent increase in cell numbers was observed at subsequent time points. Irradiation had an adverse effect on cell survival and proliferation. The number of cells detected in both irradiated and non-irradiated subjects was increased in those subjects that received transplants with hair follicle pores.

DISCUSSION

This in-vivo study confirms that radiation negatively affects the survival and proliferation of fibroblasts seeded onto a human dermis transplant. The presence of hair follicle pores in the dermis transplants is shown to have a positive effect on cell survival and proliferation even in irradiated subjects.

Laser-assisted indocyanine green dye angiography accurately predicts the split-thickness graft timing of integra artificial dermis

BACKGROUND

The use of an artificial dermal substitute such as Integra-a bilaminate combination of thin silicone and cross-linked bovine tendon collagen and chondroitin-6-sulfate-has become a popular method to address large surface area wounds or smaller, complex wounds devoid of a vascular bed. The incorporation of Integra depends on a vascular wound bed or periphery and can take 4 weeks or longer to occur. If the Integra has not fully incorporated at the time of placement of the split-thickness graft, complete graft loss may result. The availability of a minimally invasive method to assess the incorporation of Integra would be of great value.

METHODS

Two 5 × 10-cm paraspinal full-thickness wounds were created on 3 female swine. Wounds were randomly assigned full-thickness skin graft or Integra (Plainsboro, NJ) treatment. Both types of grafts were placed after the application of fibrin glue (Tisseel, Deerfield, Ill) to the wound bed. Laser Doppler imaging (LDI) (Moor), indocyanine green dye (ICG) angiography (LifeCell SPY), and clinical scoring were performed weekly for a period of 8 weeks after grafting. At 4 weeks, the silicone layer of the Integra was removed, and a culture of autologous keratinocytes was applied. A 4-mm punch biopsy sample of each graft was taken 1, 2, 4, 6, 7, and 8 weeks postoperatively for histologic analysis.

RESULTS

Both ICG angiography and LDI perfusion measurements noted an increase in perfusion at the Integra graft site that peaked 3 weeks after grafting, corresponding with the start of neovascularization and the optimal time for the application of a split-thickness skin graft. indocyanine green dye angiography measurements exhibit greater reproducibility between animals at late time points as compared with LDI. This decrease in LDI precision is directly related to increases in scar tissue thickness of greater than 5 mm as determined via histologic analysis and corresponds with the accepted maximum penetration depth of the LDI laser.

CONCLUSIONS

Indocyanine green dye angiography may provide valuable information as to graft integrity and split-thickness skin graft timing at late time points. Range of LDI seems to be insufficient for split-thickness graft timing or late time point accuracy. Future exploration of ICG angiography potential will involve tracking Integra graft delay in porcine models.

Comparative experimental study of wound healing in mice: Pelnac versus Integra

Strategies for skin regeneration have been developed to provide effective treatment for cutaneous wounds and disease. Dermal substitutes have been used to cover the lesion to facilitate cell colonization, thereby promoting dermal regeneration. However, very little is known about Pelnac matrix especially at histological level. Therefore, the present work carried out an experimental in vivo comparative analysis between Pelnac and Integra, the most used dermal templates, in a mouse model of full-thickness skin wounds. Histological sections performed at the 3^rd, 6^th and 9^th days after surgery were analyzed with regard to inflammatory response and vascularization. Both templates were completely incorporated in all animals at the end of the analyzed period. Pelnac-treated animals displayed reduced granulation tissue during the first 6 days of treatment compared to the animals treated with Integra at the same time period. The number of inflammatory cells (neutrophils) was similar in both groups during the period, significantly reducing at the end of inflammatory phase (9^th day of treatment) consistent with the progression of healing process. In addition, the density of blood vessels was also statistically similar in both matrices. Therefore, the two dermal templates displayed comparable biological behavior in tissue repair. It is noteworthy that this is the first experimental study comparing Pelnac and Integra dermal templates with focus on full-thickness skin wounds.

Combined use of fenestrated-type artificial dermis and topical negative pressure wound therapy for the venous leg ulcer of a rheumatoid arthritis patient

We report a case of circumferential venous leg ulcer in a rheumatoid arthritis patient. Mesh skin grafting was performed in another hospital, but the graft failed and the patient was referred to our hospital. This ulcer was treated by the combination therapy of a fenestrated-type artificial dermis with negative pressure wound therapy (NPWT) and secondary mesh grafting using our 'grip tape technique'. NPWT was started at -100 mmHg and continued until the formation of dermis-like tissue. A section stained using haematoxylin and eosin and an anti-αSMA (α smooth muscle actin) immunohistological section of the biopsy from dermis-like tissue showed an abundant infiltration of fibroblasts and capillary formation beneath the fenestration of the silicone sheet. Threefold mesh skin grafting was subsequently performed and it was taken up completely. The fenestrated-type artificial dermis in combination with NPWT produced good results without infection in the treatment of complex wounds. In addition, our 'grip tape technique' was useful to apply polyurethane foam to the entire surface of the lower leg.

Immediate evaluation of neovascularization in a grafted bilayered artificial dermis using laser Doppler imaging

BACKGROUND

A bilayered artificial dermis is widely applied for skin defects. Its collagen sponge is biodegraded and replaced with dermis-like tissue after application. There is no reliable method for quantitatively evaluating the blood flow of artificial dermis. In this study, we used laser Doppler imaging to evaluate the perfusion of artificial dermis.

MATERIALS AND METHODS

Twelve patients treated with artificial dermis and secondary skin grafting were included. We measured the perfusion unit just after application of artificial dermis, 1 week after, and before skin grafting.

RESULTS

Secondary skin grafts of 6 patients took completely, and the others showed partial necrosis. Laser Doppler imaging could detect blood flow in the artificial dermis, and a significant difference was observed in perfusion units between the "complete take" group and "partial necrosis" group before grafting (P < 0.05).

CONCLUSIONS

Laser Doppler imaging could be a useful and noninvasive technique for the evaluation of blood flow to the artificial dermis before grafting.

Review collagen-based biomaterials for wound healing

With its wide distribution in soft and hard connective tissues, collagen is the most abundant of animal proteins. In vitro, natural collagen can be formed into highly organized, three-dimensional scaffolds that are intrinsically biocompatible, biodegradable, nontoxic upon exogenous application, and endowed with high tensile strength. These attributes make collagen the material of choice for wound healing and tissue engineering applications. In this article, we review the structure and molecular interactions of collagen in vivo; the recent use of natural collagen in sponges, injectables, films and membranes, dressings, and skin grafts; and the on-going development of synthetic collagen mimetic peptides as pylons to anchor cytoactive agents in wound beds.