Cellular response to a novel fetal acellular collagen matrix: implications for tissue regeneration

Bacterial cellulose matrix and acellular dermal matrix seeded with fibroblasts grown in platelet-rich plasma supplemented medium, compared to free gingival grafts: a randomized animal study

PURPOSE

Mucogingival defects (MGDs), such as dental root recessions, decreased vestibular depth, and absence of keratinized tissues, are commonly seen in dental clinics. MGDs may result in functional, aesthetic, and hygienic concerns. In these situations, autogenous soft tissue grafts are considered the gold-standard treatment. This study compares the healing process of free gingival grafts (FGGs) to bacterial cellulose matrix (BCM) and human acellular dermal matrix (ADM) seeded with fibroblasts from culture supplemented with platelet-rich plasma in a rat model.

METHODS

Surgical defects were made in rats, which received the following treatments in a randomized manner: group I, negative control (defect creation only); group II, positive control (FGG); group III, BCM; group IV, BCM + fibroblasts; group V, ADM; and group VI, ADM + fibroblasts. Clinical, histological, and immunological analyses were performed 15 days after grafting. Clinical examinations recorded epithelium regularity and the presence of ulcers, erythema, and/or edema.

RESULTS

The histological analysis revealed the degree of reepithelization, width, regularity, and presence of keratin. The Fisher exact statistical test was applied to the results (P<0.05). No groups showed ulcers except for group I. All groups had regular epithelium without erythema and without edema. Histologically, all groups exhibited regular epithelium with keratinization, and myofibroblasts were present in the connective tissue. The groups that received engineered grafts showed similar clinical and histological results to the FGG group.

CONCLUSIONS

Within the limitations of this study, it was concluded that BCM and ADM can be used as cell scaffolds, with ADM yielding the best results. This study supports the use of this technical protocol in humans.

Novel Reconstructive Ladder for Reestablishing Functional Skin Graft Coverage in Chronic Lower Extremity Wounds

Background

Chronic lower extremity (LE) wounds frequently require significant interventions to close. The success of any method depends on an adequately prepared wound bed, while factors including wound size, perfusion, contamination, or exposed tissue structures can thwart efforts. We propose a standardized algorithm of care utilizing an acellular dermal matrix, split-thickness skin graft (STSG), and negative pressure wound therapy (NPWT) for the treatment of LE wounds.

Methods

This was a single-center, retrospective cohort study examining patients who underwent LE wound debridement, placement of fetal bovine dermis (FBD), and STSG between 2016 and 2022. The primary outcome was wound closure, while secondary outcomes were wound infection and amputation-free survival.

Results

Twenty patients (mean age 59 years, M:F 12:8)-including 24 LE venous ulcers (29.4%), amputation sites (29.4%), diabetic foot ulcers (25.0%), and atypical wounds (16.7%) with an average area of 39.15 cm2-underwent debridement and FBD placement followed by STSG a median of 61 days thereafter. Of these patients, 83.3% received NPWT after FBD and STSG with 86% closure. There was successful engraftment in 92% of wounds whose FBD placement was within 2 months of STSG. Of wounds that had <50% engraftment, 75% had a STSG placed over 2 months after FBD placement. Of those patients with post-STSG infection, 75% had the graft placed >2 months after FBD placement, one of which required proximal amputation.

Conclusions

By following a treatment plan including debridement with treatment of infection, application of FBD with placement of STSG within 2 months thereafter, and reinforcing NPWT, chronic wounds will have an increased rate of successful reepithelialization. Many cases experienced delays from FBD engraftment until STSG application due to schedule and insurance impediments, which led to less favorable outcomes. Therefore, a protocol that involves scheduling the placement of STSG 4 weeks after successful engraftment of FBD has been adopted.

Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer: A review

The complication of diabetes, which is known as diabetic foot ulcer (DFU), is a significant concern due to its association with high rates of disability and mortality. It not only severely affects patients’ quality of life, but also imposes a substantial burden on the healthcare system. In spite of efforts made in clinical practice, treating DFU remains a challenging task. While mesenchymal stem cell (MSC) therapy has been extensively studied in treating DFU, the current efficacy of DFU healing using this method is still inadequate. However, in recent years, several MSCs-based drug delivery systems have emerged, which have shown to increase the efficacy of MSC therapy, especially in treating DFU. This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

How to Select an Extracellular Matrix for Wound Repair: A Comprehensive Review

Background

An extracellular matrix (ECM) is a network of proteins and other molecules that provide support and structure to cells and tissues in the body. Since its discovery in 1930, researchers have reproduced the ECM through an array of evolving technologies, developing products that accelerate healing times, minimize scarring, and reduce pain. When selecting which ECM product to use, physicians rely on personal experience while considering wound location, type of tissue lost, exposed structures, chronicity, and even the patient's religious preferences. While comparison trials between a few different types of ECMs exist, there lacks a thorough investigation that assesses a majority of ECMs against each other.

Methods

Herein, we conducted a literature review using the PubMed database and utilized 71 articles to identify the best ECM for wound healing and positive patient outcomes. The primary search terms included extracellular matrix, xenograft, porcine, bovine, allograft, bioengineered matrix, acellularized fish skin, wounds, wound healing, and wound care. We did not exclude any specific type of research, but predominantly reviewed clinical trials, case series, and other review articles. We focused on the most popular and commonly used ECMs and constructed our results into the Table.

Results

We compared the indications, advantages, and disadvantages of each ECM and concisely illustrated these findings to provide a guide on how to select an ECM (Table). Allografts, whether they are glycerol or cryopreserved, suffice as a treatment choice and are superior to exposure healing. However, they do not produce healing at the same rate or quality as bioengineered matrices, porcine and bovine xenografts, or acellularized fish skin (AFS). Bioengineered matrices and porcine and bovine xenografts offer antimicrobial properties, low immunogenicity, cost effectiveness, and availability. The compromise with these ECMs is with healing times and cosmesis. Acellularized fish skin (AFS) provides diverse utility, antimicrobial activity, low immunogenicity, faster healing times, and cosmetic superiority. However, AFS yields a potential cost burden and is not plentiful or easily accessible in some parts of the world.

Conclusions

Our findings assist in removing the subjectivity component of selecting an ECM and suggest further comparison or head-to-head trials would yield a more algorithmic approach to wound healing. We suggest to consider implementing the Disabilities of the Arm, Shoulder, and Hand (DASH) score as an additional objective comparison method in these future trials.

Scaffold-based delivery of mesenchymal stromal cells to diabetic wounds

Foot ulceration is a major complication of diabetes mellitus, which results in significant human suffering and a major burden on healthcare systems. The cause of impaired wound healing in diabetic patients is multifactorial with contributions from hyperglycaemia, impaired vascularization and neuropathy. Patients with non-healing diabetic ulcers may require amputation, creating an urgent need for new reparative treatments. Delivery of stem cells may be a promising approach to enhance wound healing because of their paracrine properties, including the secretion of angiogenic, immunomodulatory and anti-inflammatory factors. While a number of different cell types have been studied, the therapeutic use of mesenchymal stromal cells (MSCs) has been widely reported to improve delayed wound healing. However, topical administration of MSCs via direct injection has several disadvantages, including low cell viability and poor cell localization at the wound bed. To this end, various biomaterial conformations have emerged as MSC delivery vehicles to enhance cell viability and persistence at the site of implantation. This paper discusses biomaterial-based MSCs therapies in diabetic wound healing and highlights the low conversion rate to clinical trials and commercially available therapeutic products.

Acellular Dermal Matrix Prevents Esophageal Stricture After Full Circumferential Endoscopic Submucosal Dissection in a Porcine Model

Esophageal stricture is a common complication after endoscopic submucosal dissection (ESD), especially in full circumferential ESD. This study investigated fully covered self-expanding metal stent (FCSEMS) placement with an acellular dermal matrix (ADM) for preventing post-ESD esophageal stricture. Twelve Bama minipigs were randomly divided into two groups, which underwent full circumferential ESD in the distal esophagus. In group A, an FCSEMS with ADM was placed at the mucosal defect, whereas group B underwent standard FCSEMS placement. The stent was removed during gastroscopy 2 weeks after the ESD procedure. At the fourth week, gastroscopy was repeated to evaluate local healing and stenosis. The animals were sacrificed, esophageal specimens were obtained for macroscopic and histological evaluation, and serum C-reactive protein (CRP) levels were quantified. Four weeks post ESD, dysphagia occurrence was lesser in group A than in group B. Group A demonstrated lesser esophageal stricture on macroscopic evaluation (21.02 ± 16.65% vs. 57.41 ± 8.48%, p = 0.001) in the form of enhanced re-epithelization (99.13 ± 0.98% vs. 96.63 ± 1.64%, p = 0.009), diminished submucosal fibrosis (1117.53 ± 188.83 um vs. 1834.69 ± 421.99 um, p = 0.003), and attenuated inflammatory infiltration (121.00 ± 30.66 vs. 188.17 ± 64.92, p = 0.045). The increase in the serum CRP level was lower in group A than in group B at 4 weeks post-ESD. FCSEMS combined with ADM can enhance re-epithelization in the process of wound healing and significantly reduce the degree of esophageal stenosis after circumferential ESD. This study provided important preclinical findings for subsequent clinical trials.

Regenerative Activities of ROS-Modulating Trace Metals in Subcutaneously Implanted Biodegradable Cryogel

Divalent trace metals (TM), especially copper (Cu), cobalt (Co) and zinc (Zn), are recognized as essential microelements for tissue homeostasis and regeneration. To achieve a balance between therapeutic activity and safety of administered TMs, effective gel formulations of TMs with elucidated regenerative mechanisms are required. We studied in vitro and in vivo effects of biodegradable macroporous cryogels doped with Cu, Co or Zn in a controllable manner. The extracellular ROS generation by metal dopants was assessed and compared with the intracellular effect of soluble TMs. The stimulating ability of TMs in the cryogels for cell proliferation, differentiation and cytokine/growth factor biosynthesis was characterized using HSF and HUVEC primary human cells. Multiple responses of host tissues to the TM-doped cryogels upon subcutaneous implantation were characterized taking into account the rate of biodegradation, production of HIF-1α/matrix metalloproteinases and the appearance of immune cells. Cu and Zn dopants did not disturb the intact skin organization while inducing specific stimulating effects on different skin structures, including vasculature, whereas Co dopant caused a significant reorganization of skin layers, the appearance of multinucleated giant cells, along with intense angiogenesis in the dermis. The results specify and compare the prooxidant and regenerative potential of Cu, Co and Zn-doped biodegradable cryogels and are of particular interest for the development of advanced bioinductive hydrogel materials for controlling angiogenesis and soft tissue growth.

Fetal bovine acellular dermal matrix for the closure of diabetic foot ulcers: a prospective randomised controlled trial

AIM

The purpose of this clinical trial was to evaluate the safety and efficacy of a fetal bovine acellular dermal matrix (FBADM) plus standard of care (SOC) for treating hard-to-heal diabetic foot ulcers (DFUs).

METHOD

A prospective, multi-centre, randomised controlled trial was carried out. The study included a 2-week run-in period, a 12-week treatment phase and a 4-week follow-up phase. The primary endpoint was complete wound closure at 12 weeks.

RESULTS

Twenty-one US sites enrolled and randomised 226 patients with hard-to-heal DFUs. The study was terminated early due to the COVID-19 pandemic, which led to a modified intent-to-treat (mITT) population of 207 patients, with 103 in the FBADM group and 104 in the SOC group. Of these participants, 161 completed the study per protocol (mPP population), with 79 receiving FBADM, and 82 without. At the first analysis point, patients treated with FBADM were found to be significantly more likely to achieve complete wound closure compared with SOC alone (mITT: 45.6% versus 27.9% p=0.008; mPP: 59.5% versus 35.6% p=0.002). The difference in outcome yielded an odds ratio of 2.2 (95% confidence interval (CI): 1.2, 3.9; p=0.008). Median time to closure within 12 weeks was 43 days for the FBADM group compared to 57 days for the SOC group (p=0.36). The median number of applications of FBADM to achieve closure was one. Adverse events were similar between groups and no product-related serious adverse events occurred.

CONCLUSIONS

These results indicate that in many cases a single application of FBADM in conjunction with SOC offers a safe, faster and more effective treatment of DFUs than SOC alone.

Skin substitutes with noncultured autologous skin cell suspension heal porcine full-thickness wounds in a one-stage procedure

Clinical application of skin substitute is typically a two-stage procedure with application of skin substitute matrix to the wound followed by engraftment of a split-thickness skin graft (STSG). This two-stage procedure requires multiple interventions, increasing the time until the wound is epithelialised. In this study, the feasibility of a one-stage procedure by combining bioengineered collagen-chondroitin-6-sulfate (DS1) or decellularised fetal bovine skin substitute (DS2) with autologous skin cell suspension (ASCS) in a porcine full-thickness wound healing model was evaluated. Twelve full-thickness excisional wounds on the backs of pigs received one of six different treatments: empty; ASCS; DS1 with or without ASCS; DS2 with or without ASCS. The ASCS was prepared using a point-of-care device and was seeded onto the bottom side of DS1, DS2, and empty wounds at 80 000 cells/cm² . Wound measurements and photographs were taken on days 0, 9, 14, 21, 28, 35, and 42 post-wounding. Histological analysis was performed on samples obtained on days 9, 14, 28, and 42. Wounds in the empty group or with ASCS alone showed increased wound contraction, fibrosis, and myofibroblast density compared with other treatment groups. The addition of ASCS to DS1 or DS2 resulted in a marked increase in re-epithelialisation of wounds at 14 days, from 15 ± 11% to 71 ± 20% (DS1 vs DS1 + ASCS) or 28 ± 14% to 77 ± 26 (DS2 vs DS2 + ASCS) despite different mechanisms of tissue regeneration employed by the DS used. These results suggest that this approach may be a viable one-stage treatment in clinical practice.

Decellularized xenografts in regenerative medicine: From processing to clinical application

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.

Accelerated Wound Closure of Deep Partial Thickness Burns with Acellular Fish Skin Graft

Thermal injuries are caused by exposure to a variety of sources, and split thickness skin grafts are the gold standard treatment for severe burns; however, they may be impossible when there is no donor skin available. Large total body surface area burns leave patients with limited donor site availability and create a need for treatments capable of achieving early and complete coverage that can also retain normal skin function. In this preclinical trial, two cellular and tissue based products (CTPs) are evaluated on twenty-four 5 × 5 deep partial thickness (DPT) burn wounds. Using appropriate pain control methods, DPT burn wounds were created on six anesthetized Yorkshire pigs. Wounds were excised one day post-burn and the bleeding wound beds were subsequently treated with omega-3-rich acellular fish skin graft (FSG) or fetal bovine dermis (FBD). FSG was reapplied after 7 days and wounds healed via secondary intentions. Digital images, non-invasive measurements, and punch biopsies were acquired during rechecks performed on days 7, 14, 21, 28, 45, and 60. Multiple qualitative measurements were also employed, including re-epithelialization, contraction rates, hydration, laser speckle, and trans-epidermal water loss (TEWL). Each treatment produced granulated tissue (GT) that would be receptive to skin grafts, if desired; however, the FSG induced GT 7 days earlier. FSG treatment resulted in faster re-epithelialization and reduced wound size at day 14 compared to FBD (50.2% vs. 23.5% and 93.1% vs. 106.7%, p < 0.005, respectively). No differences in TEWL measurements were observed. The FSG integrated into the wound bed quicker as evidenced by lower hydration values at day 21 (309.7 vs. 2500.4 µS, p < 0.05) and higher blood flow at day 14 (4.9 vs. 3.1 fold change increase over normal skin, p < 0.005). Here we show that FSG integrated faster without increased contraction, resulting in quicker wound closure without skin graft application which suggests FSG improved burn wound healing over FBD.

CICAFAST: comparison of a biological dressing composed of fetal fibroblasts and keratinocytes on a split-thickness skin graft donor site versus a traditional dressing: a randomized controlled trial

BACKGROUND

Wound repair is one of the most complex biological processes of human life. Allogeneic cell-based engineered skin substitutes provide off-the-shelf temporary wound coverage and act as biologically active dressings, releasing growth factors, cytokines and extracellular matrix components essential for proper wound healing. However, they are susceptible to immune rejection and this is their major weakness. Thanks to their low immunogenicity and high effectiveness in regeneration, fetal skin cells represent an attractive alternative to the commonly used autologous and allogeneic skin grafts.

METHODS/DESIGN

We developed a new dressing comprising a collagen matrix seeded with a specific ratio of active fetal fibroblasts and keratinocytes. These produce a variety of healing growth factors and cytokines which will increase the speed of wound healing and induce an immunotolerant state, with a slight inflammatory reaction and a reduction in pain. The objective of this study is to demonstrate that the use of this biological dressing for wound healing at the split-thickness skin graft (STSG) donor site, reduces the time to healing, decreases other co-morbidities, such as pain, and improves the appearance of the scar. This investigation will be conducted as part of a randomized study comparing our new biological dressing with a conventional treatment in a single patient, thus avoiding the factors that may influence the healing of a graft donor site.

DISCUSSION

This clinical trial should enable the development of a new strategy for STSG donor-wound healing based on a regenerative dressing. The pain experienced in the first few days of STSG healing is well known due to the exposure of sensory nerve endings. Reducing this pain will also reduce analgesic drug intake and the duration of sick leave. Our biological dressing will meet the essential need of surgeons to "re-crop" from existing donor sites, e.g., for thermal-burn patients. By accelerating healing, improving the appearance of the scar and reducing pain, we hope to improve the conditions of treatment for skin grafts.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03334656 . Registered on 7 November 2017.

Biological Mechanisms of Chronic Wound and Diabetic Foot Healing: The Role of Collagen

The treatment of chronic wounds is a continuously developing research focus. The problems of excessive mechanical forces, infection, inflammation, reduced production of growth factors, and lack of collagen will affect the results of treatment. The purpose of this study was to analysse the elements that lead to long-term non-healing of chronic wounds and trophic ulcers, including diabetic foot syndrome, by determining the optimal treatment algorithm. The paper presents an analysis of the world literature on the etiopathogenesis and principles of chronic wound treatment in diabetic foot syndrome. The epidemiology of chronic wounds of different genesis is presented. The issues of physiological and metabolic disorders in chronic ulcers affecting the process of wound healing are discussed. Particular attention is paid to collagen, which is a protein that forms the basis of connective tissue; collagen ensures the strength and elasticity of the skin, which confirms the importance of its role not only in aesthetics but also in the process of wound healing. Different types of collagen and their roles in the mechanisms of chronic wound healing in diabetic foot syndrome are described. The results of clinical studies evaluating the effectiveness of medical products and preparations, consisting of collagen with preserved (native collagen) and fractionated structures, in treating chronic wounds of diabetic foot syndrome are analysed. It has been shown that the use of native collagen preparations is a promising treatment for chronic ulcers and wounds, including diabetic foot syndrome, which makes it possible to increase the effectiveness of treatment and reduce the economic costs of managing these patients.

Ionic silver functionalized ovine forestomach matrix - a non-cytotoxic antimicrobial biomaterial for tissue regeneration applications

BACKGROUND

Antimicrobial technologies, including silver-containing medical devices, are increasingly utilized in clinical regimens to mitigate risks of microbial colonization. Silver-functionalized resorbable biomaterials for use in wound management and tissue regeneration applications have a narrow therapeutic index where antimicrobial effectiveness may be outweighed by adverse cytotoxicity. We examined the effects of ionic silver functionalization of an extracellular matrix (ECM) biomaterial derived from ovine forestomach (OFM-Ag) in terms of material properties, antimicrobial effectiveness and cytotoxicity profile.

METHODS

Material properties of OFM-Ag were assessed by via biochemical analysis, microscopy, atomic absorption spectroscopy (AAS) and differential scanning calorimetry. The silver release profile of OFM-Ag was profiled by AAS and antimicrobial effectiveness testing utilized to determine the minimum effective concentration of silver in OFM-Ag in addition to the antimicrobial spectrum and wear time. Biofilm prevention properties of OFM-Ag in comparison to silver containing collagen dressing materials was quantified via in vitro crystal violet assay using a polymicrobial model. Toxicity of ionic silver, OFM-Ag and silver containing collagen dressing materials was assessed toward mammalian fibroblasts using elution cytoxicity testing.

RESULTS

OFM-Ag retained the native ECM compositional and structural characteristic of non-silver functionalized ECM material while imparting broad spectrum antimicrobial effectiveness toward 11 clinically relevant microbial species including fungi and drug resistant strains, maintaining effectiveness over a wear time duration of 7-days. OFM-Ag demonstrated significant prevention of polymicrobial biofilm formation compared to non-antimicrobial and silver-containing collagen dressing materials. Where silver-containing collagen dressing materials exhibited cytotoxic effects toward mammalian fibroblasts, OFM-Ag was determined to be non-cytotoxic, silver elution studies indicated sustained retention of silver in OFM-Ag as a possible mechanism for the attenuated cytotoxicity.

CONCLUSIONS

This work demonstrates ECM biomaterials may be functionalized with silver to favourably shift the balance between detrimental cytotoxic potential and beneficial antimicrobial effects, while preserving the ECM structure and function of utility in tissue regeneration applications.

A novel surgical technique for a rat subcutaneous implantation of a tissue engineered scaffold

Objectives

Subcutaneous implantations in small animal models are currently required for preclinical studies of acellular tissue to evaluate biocompatibility, including host recellularization and immunogenic reactivity.

Methods

Three rat subcutaneous implantation methods were evaluated in six Sprague Dawley rats. An acellular xenograft made from porcine pericardium was used as the tissue-scaffold. Three implantation methods were performed; 1) Suture method is where a tissue-scaffold was implanted by suturing its border to the external oblique muscle, 2) Control method is where a tissue-scaffold was implanted without any suturing or support, 3) Frame method is where a tissue-scaffold was attached to a circular frame composed of polycaprolactone (PCL) biomaterial and placed subcutaneously. After 1 and 4 weeks, tissue-scaffolds were explanted and evaluated by hematoxylin and eosin (H&E), Masson’s trichrome, Picrosirius Red, transmission electron microscopy (TEM), immunohistochemistry, and mechanical testing.

Results

Macroscopically, tissue-scaffold degradation with the suture method and tissue-scaffold folding with the control method were observed after 4 weeks. In comparison, the frame method demonstrated intact tissue scaffolds after 4 weeks. H&E staining showed progressive cell repopulation over the course of the experiment in all groups with acute and chronic inflammation observed in suture and control methods throughout the duration of the study. Immunohistochemistry quantification of CD3, CD 31, CD 34, CD 163, and αSMA showed a statistically significant differences between the suture, control and frame methods (P < 0.05) at both time points. The average tensile strength was 4.03 ± 0.49, 7.45 ± 0.49 and 5.72 ± 1.34 (MPa) after 1 week and 0.55 ± 0.26, 0.12 ± 0.03 and 0.41 ± 0.32 (MPa) after 4 weeks in the suture, control, and frame methods; respectively. TEM analysis showed an increase in inflammatory cells in both suture and control methods following implantation.

Conclusion

Rat subcutaneous implantation with the frame method was performed with success and ease. The surgical approach used for the frame technique was found to be the best methodology for in vivo evaluation of tissue engineered acellular scaffolds, where the frame method did not compromise mechanical strength, but it reduced inflammation significantly.

Fetal Bovine Collagen Matrix in the Treatment of a Full Thickness Burn Wound: A Case Report With Long-Term Follow-Up

The treatment of full thickness skin wounds commonly associated with large burns continues to represent a challenging clinical entity. The current treatment for large TBSA burns is split thickness autologous skin grafting; however, this treatment often results in poor textural durability, hypertrophic scarring, and fibrotic contractures. In this case report, we describe our experience and long-term follow-up results after the application of fetal bovine collagen (FBC) matrix (PriMatrix, TEI Biosciences, Boston, MA) to burn wounds clinically assessed as full thickness that healed without the need for subsequent skin grafting. The patient presented with 25% TBSA burns and was debrided and covered with FBC on postburn day 7. By postoperative day 12, the patient had large areas of reepithelialization distributed throughout the wound bed. By postoperative day 26, the patient had significantly more areas of wound closure and was discharged. Reepithelialization and repigmentation continued, and long-term follow-up after 26 months demonstrated complete reepithelialization and nearly complete repigmentation, without the appearance of contractures or hypertrophic scarring. This case report highlights the use of FBC as a scaffold capable of dermal regeneration and spontaneous reepithelialization with an excellent long-term functional and cosmetic outcome.

Pediatric Thermal Burns and Treatment: A Review of Progress and Future Prospects

Burn injuries are a devastating critical care problem. In children, burns continue to be a major epidemiologic problem around the globe resulting in significant morbidity and death. Apparently, treating these burn injuries in children and adults remains similar, but there are significant physiological and psychological differences. The dermal layer of the skin is generally thinner in neonates, infants, and children than in adults. Enhanced evaporative loss and need for isotonic fluids increases the risk of hypothermia in the pediatric population. The pain management of the children with major burns challenges the skills of the personnel of every unit. Managing these wounds requires intensive therapeutic treatment for multi-organ dysfunction, and surgical treatment to prevent sepsis and other complications that further delay wound closure. Alternatives to the practice of donor site harvest and autografting for the treatment of severe burns and other complex skin defects are urgently needed for both adult and pediatric populations. This review article focuses on thermal burn pathophysiology and pain management and provides an overview of currently approved products used for the treatment of pediatric burn wounds. A new promising approach has been presented as a first-line therapy in the treatment of burns to reduce surgical autografting in pediatric patients.

MSCs on an acellular dermal matrix (ADM) sourced from neonatal mouse skin regulate collagen reconstruction of granulation tissue during adult cutaneous wound healing

The novel strategy of MSCs seeded on ADM sourced from neonatal mouse skin promotes full-thickness cutaneous wound healing.

Suppression of α Smooth Muscle Actin Accumulation by Bovine Fetal Dermal Collagen Matrix in Full Thickness Skin Wounds

The suppression of elements associated with wound contracture and unfavorable scarring is a potentially important strategy in clinical wound management. In this study, the presence of α smooth muscle actin (αSMA), a protein involved in wound contraction, was analyzed in a series of wounds in which bovine fetal collagen (BFC) acellular dermal matrix (PriMatrix) was used in staged split thickness skin graft procedures. The results obtained through histological and quantitative image analyses of incidental biopsies from these wounds demonstrated a suppression of αSMA in the wound regions occupied by assimilated BFC relative to increased levels of αSMA found in other areas of the wound. The αSMA levels found in assimilated BFC were similar to αSMA levels in uninjured human dermis. These findings suggest a mechanism by which application of BFC could decrease contraction of full thickness skin wounds.

The use of PriMatrix, a fetal bovine acellular dermal matrix, in healing chronic diabetic foot ulcers: a prospective multicenter study

OBJECTIVE

The objective of this multicenter study was to prospectively evaluate the healing outcomes of chronic diabetic foot ulcers (DFUs) treated with PriMatrix (TEI Biosciences, Boston, Massachusetts), a fetal bovine acellular dermal matrix.

METHODS

Inclusion criteria required the subjects to have a chronic DFU that ranged in area from 1 to 20 cm² and failed to heal more than 30% during a 2-week screening period when treated with moist wound therapy. For qualifying subjects, PriMatrix was secured into a clean, sharply debrided wound; dressings were applied to maintain a moist wound environment, and the DFU was pressure off-loaded. Wound area measurements were taken weekly for up to 12 weeks, and PriMatrix was reapplied at the discretion of the treating physician.

RESULTS

A total of 55 subjects were enrolled at 9 US centers with 46 subjects progressing to study completion. Ulcers had been in existence for an average of 286 days, and initial mean ulcer area was 4.34 cm². Of the subjects completing the study, 76% healed by 12 weeks with a mean time to healing of 53.1 ± 21.9 days. The mean number of applications for these healed wounds was 2.0 ± 1.4, with 59.1% healing with a single application of PriMatrix and 22.9% healing with 2 applications. For subjects not healed by 12 weeks, the average wound area reduction was 71.4%.

CONCLUSION

The results of this multicenter prospective study demonstrate that the use of PriMatrix integrated with standard-of-care therapy is a successful treatment regimen to heal DFUs.

Differentiation of mesenchymal stem cells into neuronal cells on fetal bovine acellular dermal matrix as a tissue engineered nerve scaffold

The purpose of this study was to assess fetal bovine acellular dermal matrix as a scaffold for supporting the differentiation of bone marrow mesenchymal stem cells into neural cells following induction with neural differentiation medium. We performed long-term, continuous observation of cell morphology, growth, differentiation, and neuronal development using several microscopy techniques in conjunction with immunohistochemistry. We examined specific neuronal proteins and Nissl bodies involved in the differentiation process in order to determine the neuronal differentiation of bone marrow mesenchymal stem cells. The results show that bone marrow mesenchymal stem cells that differentiate on fetal bovine acellular dermal matrix display neuronal morphology with unipolar and bi/multipolar neurite elongations that express neuronal-specific proteins, including βIII tubulin. The bone marrow mesenchymal stem cells grown on fetal bovine acellular dermal matrix and induced for long periods of time with neural differentiation medium differentiated into a multilayered neural network-like structure with long nerve fibers that was composed of several parallel microfibers and neuronal cells, forming a complete neural circuit with dendrite-dendrite to axon-dendrite to dendrite-axon synapses. In addition, growth cones with filopodia were observed using scanning electron microscopy. Paraffin sectioning showed differentiated bone marrow mesenchymal stem cells with the typical features of neuronal phenotype, such as a large, round nucleus and a cytoplasm full of Nissl bodies. The data suggest that the biological scaffold fetal bovine acellular dermal matrix is capable of supporting human bone marrow mesenchymal stem cell differentiation into functional neurons and the subsequent formation of tissue engineered nerve.

The Use of Fetal Bovine Dermal Scaffold (PriMatrix) in the Management of Full-Thickness Hand Burns

OBJECTIVE

Management of full-thickness burn wounds represents a challenge when reconstructive options are not applicable. Fetal bovine dermal matrix is a bioactive collagen scaffold that assimilates into wounds and stimulates vascularization and dermal regeneration.

METHODS

We present the use of fetal bovine dermal scaffold PriMatrix in the treatment of a patient who sustained scald-immersion full-thickness burns of her bilateral hands that failed conventional wound therapy.

RESULTS

A 71-year-old woman with advanced Parkinson's disease sustained self-induced 5% mixed second- and third-degree scald-immersion burns of her bilateral hands and fingers. The patient underwent extensive debridement that resulted in partially avascular wounds measuring 66 cm(2) and 72 cm(2) with exposed extensor tendons and no evidence of bleeding. Meshed homograft was applied, but her hands remained partly avascular. PriMatrix fetal bovine dermal scaffold was applied to provide tissue remodeling over the bones, which allowed successful skin grafting and complete wound healing.

CONCLUSIONS

Our experience shows fetal bovine dermal scaffold to be an effective method in management of complicated burn wounds in selected cases. Further studies need to be implemented to confer this conclusion.