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

Advanced dressings based on novel biological targets for diabetic wound healing: A review

The diabetic wound is one of the most common complications of diabetes in clinic. The existing diabetic wound dressings all have bottlenecks in decreasing inflammation, stopping peripheral neuropathy, relieving local ischemia and hypoxia in diabetic wounds. These challenges are intricately linked to the roles of various growth factors, as well as matrix metalloproteinases. Thus, a comprehensive understanding of growth factors-particularly their dynamic interactions with the extracellular matrix (ECM) and cellular components-is essential. Cells and proteins that influence the synthesis of growth factors and matrix metalloproteinases emerge as potential therapeutic targets for diabetic wound management. This review discusses the latest advancements in the pathophysiology of diabetic wound healing, highlights novel biological targets, and evaluates new wound dressing strategies designed for the treatment of diabetic wounds.

The use of fetal bovine acellular dermal matrix in severe diabetic foot ulceration and threatened limbs with tissue loss the use of FBADM as an adjunct for complex wounds

OBJECTIVES

Foot ulceration associated with diabetic foot disease (DFD) and chronic limb-threatening ischaemia (CLTI) presents a complex clinical challenge and failure to heal the wound imposes a significant risk of major limb amputation (MLA). In attempt to accelerate wound healing rates and decrease MLA, tissue engineering research into bio-engineered scaffolds and skin substitutes has become a growing area of interest. Advanced wound therapies such as fetal bovine acellular dermal matrix (FBADM) may have success in the treatment of difficult to heal chronic foot ulcers. The FBADM traps and binds the patients' own epithelial cells to rebuild the dermis layer of the skin. Previous studies have suggested that wounds treated with FBADM had a faster healing rate than wounds managed with conventional dressings. However, these studies excluded foot wounds with chronic exposed bone or tendon, active infection, gangrene, or osteomyelitis and patients with uncontrolled blood glucose levels were excluded. The aim of this study was to assess the efficacy of FBADM for patients admitted to hospital acutely with severe foot ulceration secondary to DFD and CLTI.

METHODS

Between February 2020 and December 2021, inpatients admitted acutely at a single tertiary centre with a severe non-healing foot ulcer and had a wound suitable for application of a FBADM after primary debridement were included in the study. A severe non-healing foot wound was defined as a Society for Vascular Surgery Wound, Ischaemia, and foot Infection (WIfI) stage of 3 or 4. Participants were prospectively followed up at regular intervals at a multidisciplinary high-risk diabetic foot clinic until June 2022. The primary endpoint was time to wound closure. The secondary endpoints were number of applications of FBADM, readmission rate and amputation-free survival.

RESULTS

There were 22 patients included in the study with a median age of 71 (50-87) years and 15 were male. Five patients had a WIfI stage of 3 and 17 had a WIfI score of 4. Overall, 14 patients required revascularisation procedures (6 open surgery,8 endovascular intervention). A total of 18 patients achieved complete wound healing with a median time to wound healing of 178 (28-397) days. Two patients underwent a MLA and two patients died prior to complete wound healing. The median length of stay was 16.5 (5-115) days, and 4 patients were readmitted to hospital within 12 months.

CONCLUSION

FBADM may be a useful adjunct in the acute setting of complex DFD and CLTI ulceration to assist with wound healing. Future comparative prospective studies are required to further validate these preliminary findings.

Biomaterials-Based Strategies to Enhance Angiogenesis in Diabetic Wound Healing

Amidst the present healthcare issues, diabetes is unique as an emerging class of affliction with chronicity in a majority of the population. To check and control its effects, there have been huge turnover and constant development of management strategies, and though a bigger part of the health care area is involved in achieving its control and the related issues such as the effect of diabetes on wound healing and care and many of the works have reached certain successful outcomes, still there is a huge lack in managing it, with maximum effect yet to be attained. Studying pathophysiology and involvement of various treatment options, such as tissue engineering, application of hydrogels, drug delivery methods, and enhancing angiogenesis, are at constantly developing stages either direct or indirect. In this review, we have gathered a wide field of information and different new therapeutic methods and targets for the scientific community, paving the way toward more settled ideas and research advances to cure diabetic wounds and manage their outcomes.

Extracellular Matrices as Bioactive Materials for In Situ Tissue Regeneration

Bioactive materials based on a nature-derived extracellular matrix (NECM) represent a category of biomedical devices with versatile therapeutic applications in the realms of tissue repair and engineering. With advancements in decellularization technique, the inherent bioactive molecules and the innate nano-structural and mechanical properties are preserved in three-dimensional scaffolds mainly composed of collagens. Techniques such as electrospinning, three-dimensional printing, and the intricate fabrication of hydrogels are developed to mimic the physical structures, biosignalling and mechanical cues of ECM. Until now, there has been no approach that can fully account for the multifaceted properties and diverse applications of NECM. In this review, we introduce the main proteins composing NECMs and explicate the importance of them when used as therapeutic devices in tissue repair. Nano-structural features of NECM and their applications regarding tissue repair are summarized. The origins, degradability, and mechanical property of and immune responses to NECM are also introduced. Furthermore, we review their applications, and clinical features thereof, in the repair of acute and chronic wounds, abdominal hernia, breast deformity, etc. Some typical marketed devices based on NECM, their indications, and clinical relevance are summarized.

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.

Dermal Regenerative Templates in Orthopaedic Surgery

Management of soft-tissue injuries is a critical principle in the treatment of orthopaedic trauma. Understanding the options for soft-tissue reconstruction is vital for successful patient outcomes. Application of dermal regenerative templates (DRTs) in traumatic wounds has created a new rung in the reconstructive ladder bridging the gap between skin graft and flap coverage. There are multiple DRT products with specific clinical indications and mechanisms of action. This review outlines the up-to-date specifications and uses of DRT in commonly seen orthopaedic injuries.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

Use of fetal bovine dermal repair scaffold in diabetic foot ulcers with recidivism: an open-label prospective clinical study

OBJECTIVE

This study aimed to establish the effectiveness of fetal bovine dermal scaffold (FBDS) application with multilayer offloading (standard of care) over that of traditional therapies in the treatment of diabetic foot ulcers (DFUs).

METHOD

Patients from a single centre in South Florida, US were recruited for this research. All patients underwent a run-in period of standardised care and vascular testing to determine and control the ability to heal. Patients were placed in multilayer offloading total contact cast (TCC) systems with application of FBDS every four weeks. Wound measurements and efficacy of offloading were monitored weekly.

RESULTS

In an older population with diabetes and above-normal body mass index (BMI), use of FBDS was successful in wound closure, with average time to closure of 7.85 weeks for the 20 patients in this study. It should be noted that surface wound area was reduced by approximately 40% by week 4 and by almost 83% by week 9. Follow-up at three and six months showed no residual or recurrent ulcerations in this study population for 19/20 patients.

CONCLUSION

Total wound closure of hard-to-heal DFUs in this patient series study was achieved with local surgical debridement, TCC offloading and application(s) of a FBDS in older patients with above-normal BMI and in wounds of >4 weeks non-progressive healing. Furthermore, at three and six months, 19/20 patients' wounds remained closed and did not re-ulcerate.

Health economics of diabetic foot ulcer and recent trends to accelerate treatment

Diabetic foot ulcer is a preventable complication of diabetes that imposes a significant burden on the community. It leads to amputation and increased disability if left untreated and thus bears profound implications on the individual, the community and the health system at large. Diabetic foot (DF) is an area of research interest where interdisciplinary researchers are trying to elucidate the best strategy to halt the progression of chronic diabetic wounds. It is an area where tissue engineering research is making a strong impact through the use of scaffolds and skin substitutes for diabetic wound healing. This review aims at discussing the geographical health economics, its impact on healing and factors influencing financial costs of DFU. The upcoming economic and clinical impacts due to disease outbreak such as the 2020 COVID-19 has also been discussed. Finally, it will discuss novel therapy available with emphasis on skin tissue engineering scaffolds with a cost-benefit analysis. The review aims at promoting better management of people with diabetes with emphasis on emerging treatments and technologies.

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.

Recent Progress in Development of Dressings Used for Diabetic Wounds with Special Emphasis on Scaffolds

Diabetic wound (DW) is a secondary application of uncontrolled diabetes and affects about 42.2% of diabetics. If the disease is left untreated/uncontrolled, then it may further lead to amputation of organs. In recent years, huge research has been done in the area of wound dressing to have a better maintenance of DW. These include gauze, films, foams or, hydrocolloid-based dressings as well as polysaccharide- and polymer-based dressings. In recent years, scaffolds have played major role as biomaterial for wound dressing due to its tissue regeneration properties as well as fluid absorption capacity. These are three-dimensional polymeric structures formed from polymers that help in tissue rejuvenation. These offer a large surface area to volume ratio to allow cell adhesion and exudate absorbing capacity and antibacterial properties. They also offer a better retention as well as sustained release of drugs that are directly impregnated to the scaffolds or the ones that are loaded in nanocarriers that are impregnated onto scaffolds. The present review comprehensively describes the pathogenesis of DW, various dressings that are used so far for DW, the limitation of currently used wound dressings, role of scaffolds in topical delivery of drugs, materials used for scaffold fabrication, and application of various polymer-based scaffolds for treating DW.

Clinical applications of acellular dermal matrices: A review

INTRODUCTION

The extracellular matrix (ECM) plays an integral role in wound healing. It provides both structure and growth factors that allow for the organised cell proliferation. Large or complex tissue defects may compromise host ECM, creating an environment that is unfavourable for the recovery of anatomical function and appearance. Acellular dermal matrices (ADMs) have been developed from a variety of sources, including human (HADM), porcine (PADM) and bovine (BADM), with multiple different processing protocols. The objective of this report is to provide an overview of current literature assessing the clinical utility of ADMs across a broad spectrum of applications.

METHODS

PubMed, MEDLINE, EMBASE, Scopus, Cochrane and Web of Science were searched using keywords 'acellular dermal matrix', 'acellular dermal matrices' and brand names for commercially available ADMs. Our search was limited to English language articles published from 1999 to 2020 and focused on clinical data.

RESULTS

A total of 2443 records underwent screening. After removing non-clinical studies and correspondence, 222 were assessed for eligibility. Of these, 170 were included in our synthesis of the literature. While the earliest ADMs were used in severe burn injuries, usage has expanded to a number of surgical subspecialties and procedures, including orthopaedic surgery (e.g. tendon and ligament reconstructions), otolaryngology, oral surgery (e.g. treating gingival recession), abdominal wall surgery (e.g. hernia repair), plastic surgery (e.g. breast reconstruction and penile augmentation), and chronic wounds (e.g. diabetic ulcers).

CONCLUSION

Our understanding of ADM's clinical utility continues to evolve. More research is needed to determine which ADM has the best outcomes for each clinical scenario.

LAY SUMMARY

Large or complex wounds present unique reconstructive and healing challenges. In normal healing, the extracellular matrix (ECM) provides both structural and growth factors that allow tissue to regenerate in an organised fashion to close the wound. In difficult or large soft-tissue defects, however, the ECM is often compromised. Acellular dermal matrix (ADM) products have been developed to mimic the benefits of host ECM, allowing for improved outcomes in a variety of clinical scenarios. This review summarises the current clinical evidence regarding commercially available ADMs in a wide variety of clinical contexts.

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.

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.

Photobiomodulation therapy improves the growth factor and cytokine secretory profile in human type 2 diabetic fibroblasts

Impaired wound healing is a common complication of diabetes mellitus (DM) and the underlying mechanism of this impairment is still unclear. Fibroblast, as the main reconstructing cell, secretes some critical growth factors and cytokine contributing to wound healing. It is well known that DM alters the behavior of these cells and photobiomodulation therapy (PBMT) compensates some impairments in diabetic fibroblasts. Therefore, the aim of the present study was to demonstrate the impact of diabetes and the role of PBMT through low level laser irradiation on secretory profile of human diabetic fibroblasts. Primary human dermal fibroblasts from normal (HDFs) and diabetic (DHDFs) donors were harvested. For PBMT, the DHDFs were irradiated with a Helium-Neon laser at 632.8 nm wavelength and energy density of 0.5 J/cm², as laser treated group (LT-DHDFs). Next, some cellular behaviors and secretory profiling array for 60 growth factors/cytokines were investigated in LT-DHDFs and then compared with those of controls. The data showed that the PBMT could compensate such impairments occurred in DHDFs in terms of viability, proliferation, and migration. Furthermore, considering our novel findings, out of those 20 growth factors/cytokines involved in cell proliferation, immune system regulation, and cell-cell communication pathways, which significantly decreased in DHDF as compared with HDFs, the PBMT could compensate seven in LT-DHDFs as compared with DHDFs. The seven growth factor/cytokines, which are mainly involved in cell-cell communication, positive regulation of cell proliferation, and chemokine mediated pathway included BDNF, Eotaxin-3, FGF6, FGF7, Fractalkine, fit-3ligand, and GCP-2. Therefore, it is suggested that scrutinizing these differentially secreted molecules and the impaired pathways in DHDFs, in combination with those compensated in LT-DHDFs, could raise our knowledge to manage diabetic ulcer through a feasible and cost effective intervention, specifically PBMT.

Adult Human Dermal Progenitor Cell Transplantation Modulates the Functional Outcome of Split-Thickness Skin Xenografts

Following full-thickness skin injuries, epithelialization of the wound is essential. The standard of care to achieve this wound "closure" in patients is autologous split-thickness skin grafting (STSG). However, patients living with STSGs report significant chronic impairments leading to functional deficiencies such as itch, altered sensation, fragility, hypertrophic scarring, and contractures. These features are attributable to the absence of functional dermis combined with the formation of disorganized fibrotic extracellular matrix. Recent work has demonstrated the existence of dermal progenitor cells (DPCs) residing within hair follicles that function to continuously regenerate mesenchymal tissue. The present work examines whether cultured DPCs could regenerate dermis within an STSG and improve overall graft function. Adult human DPCs were transplanted into a full-thickness skin wound in immune-compromised mice and closed with a human STSG. At 3 months, human DPCs (hDPCs) had successfully integrated into the xenograft and differentiated into various regionally specified phenotypes, improving both viscoelastic properties of the graft and mitigating pruritus.

Healing of Chronic Wounds: An Update of Recent Developments and Future Possibilities

Chronic wounds are the result of disruptions in the body's usual process of healing. They are not only a source of significant pain and discomfort but also, more importantly, an unguarded port of entry for pathogens into the body. While our current understanding of this phenomenon is far from complete, findings in physiological patterns and advancements in wound healing technologies have helped develop wound management and healing solutions to this long-standing medical challenge. This review presents an overview of known wound healing mechanics, abnormalities that lead to chronic wounds, and a summary of established and new wound healing technologies. Various approaches to heal wounds are discussed, from dermal replacements to advanced biomaterial-based treatments, from cell-, synthetic-, and composite-based approaches to preclinical approaches, which make developing such products possible. While tested breakthrough products are described, the authors focused more on recently developed innovations, which are at varying stages of maturity. The review concludes with a note on future perspectives and opinions on where the field and industry are headed and where they should be. Impact Statement Wound healing is an important area of research and clinical practice, and has captured the attention of tissue engineers since the nascent beginnings of the discipline. Tissue-engineered skin was the first FDA-approved product, achieved in 1996. Despite this success, and the passage of time, healing wounds, particularly chronic wounds, remains a vexing challenge. This comprehensive review article will provide readers with a synopsis of current issues, research approaches, animal models, technologies, and products that span the continuum from early development to clinical studies, in the hope of fueling new interests and ideas to overcome this long-standing medical challenge.

Updates on Bioengineered Alternative Tissues

Over the past quarter century, the management of diabetic wounds and their sequelae has improved dramatically. One of the greatest areas of advancement includes the development of bioengineered alternative tissues that act as adjuncts to the deficits of chronic wounds and accelerate healing. The use of bioengineered alternative tissues will likely only continue to dominate the outpatient and perioperative management of chronic, recalcitrant wounds as new additional products continue to cut costs and improve wound healing expectations. This article reviews common and novel bioengineered alternative tissue products, identifying their unique composition, function, and current published outcome data.

Acellular and cellular approaches to improve diabetic wound healing

Chronic diabetic wounds represent a huge socioeconomic burden for both affected individuals and the entire healthcare system. Although the number of available treatment options as well as our understanding of wound healing mechanisms associated with diabetes has vastly improved over the past decades, there still remains a great need for additional therapeutic options. Tissue engineering and regenerative medicine approaches provide great advantages over conventional treatment options, which are mainly aimed at wound closure rather than addressing the underlying pathophysiology of diabetic wounds. Recent advances in biomaterials and stem cell research presented in this review provide novel ways to tackle different molecular and cellular culprits responsible for chronic and nonhealing wounds by delivering therapeutic agents in direct or indirect ways. Careful integration of different approaches presented in the current article could lead to the development of new therapeutic platforms that can address multiple pathophysiologic abnormalities and facilitate wound healing in patients with diabetes.

Complex Lower Extremity Wound in the Complex Host: Results From a Multicenter Registry

Background:

The complex diabetic lower extremity wound has not been well studied. There are a variety of new technologies now being applied with a paucity of evidence in evaluating their outcomes. The aim of this study is to describe clinical outcomes in the complex lower extremity wound in the comorbid host. We hypothesized that treatment choice would have minimal impact on healing outcomes in this compromised population.

Methods:

A multicenter retrospective registry of patients with diabetes and lower extremity wounds was created to compare treatment modalities of collagen–glycosaminoglycan scaffold, negative-pressure wound therapy, local tissue flap, and free tissue transfer. Statistical analyses included descriptive, proportional comparisons and Cox regression.

Results:

There were no statistical differences in age, hemoglobin A1c, or body mass index between groups. Study patients had a history of amputation (40.5%), peripheral vascular disease (54.6%), peripheral neuropathy (64.8%), end-stage renal disease (13.9%), renal/hepatic disease (40.4%), and hypertension (85%). The most common wound etiologies were surgical dehiscence (69%), diabetic neuropathic wounds (39%), and ischemic wounds (28%), most commonly located on the foot or at a prior amputation site (30%). Mean wound area was 57.9 cm² and almost half with exposed bone. There were no statistical differences between treatment groups in proportion or time to healing, recurrence, or time to return to baseline function.

Conclusions:

Commonly used treatment modalities employed for this population of patients resulted in similar outcomes. This is the first study to describe the complex diabetic lower extremity wound in a complex host.

Advances in Wound Management

Wound management is a notable healthcare and financial burden, accounting for >$10 billion in annual healthcare spending in the United States. A multidisciplinary approach involving orthopaedic and plastic surgeons, wound care nursing, and medical and support staff is often necessary to improve outcomes. Orthopaedic surgeons must be familiar with the fundamental principles and evidenced-based concepts for the management of acute and chronic wounds. Knowledge of surgical dressings, negative pressure wound therapy, tissue expanders, dermal apposition, biologics, and extracellular matrices can aide practitioners in optimizing wound care.

Immunological challenges associated with artificial skin grafts: available solutions and stem cells in future design of synthetic skin

The repair or replacement of damaged skins is still an important, challenging public health problem. Immune acceptance and long-term survival of skin grafts represent the major problem to overcome in grafting given that in most situations autografts cannot be used. The emergence of artificial skin substitutes provides alternative treatment with the capacity to reduce the dependency on the increasing demand of cadaver skin grafts. Over the years, considerable research efforts have focused on strategies for skin repair or permanent skin graft transplantations. Available skin substitutes include pre- or post-transplantation treatments of donor cells, stem cell-based therapies, and skin equivalents composed of bio-engineered acellular or cellular skin substitutes. However, skin substitutes are still prone to immunological rejection, and as such, there is currently no skin substitute available to overcome this phenomenon. This review focuses on the mechanisms of skin rejection and tolerance induction and outlines in detail current available strategies and alternatives that may allow achieving full-thickness skin replacement and repair.

Current Status and Future of Skin Substitutes for Chronic Wound Healing

Chronic wounds, including diabetic ulcers, pressure ulcers, venous ulcers, and arterial insufficiency ulcers, are both difficult and expensive to treat. Conventional wound care may sometimes lead to suboptimal wound healing and significant morbidity and mortality for patients. The use of skin substitutes provides an alternative therapy showing superior efficacy and, in some cases, similar cost-effectiveness compared to traditional treatments. This review discusses the different types of currently available commercial skin substitutes for use in chronic wounds as well as the paucity of strong evidence supporting their use. It then delves into the limitations of these skin substitutes and examines the most recent research targeting these limitations.

Challenges in the Treatment of Chronic Wounds

Significance: Chronic wounds include, but are not limited, to diabetic foot ulcers, venous leg ulcers, and pressure ulcers. They are a challenge to wound care professionals and consume a great deal of healthcare resources around the globe. This review discusses the pathophysiology of complex chronic wounds and the means and modalities currently available to achieve healing in such patients. Recent Advances: Although often difficult to treat, an understanding of the underlying pathophysiology and specific attention toward managing these perturbations can often lead to successful healing. Critical Issues: Overcoming the factors that contribute to delayed healing are key components of a comprehensive approach to wound care and present the primary challenges to the treatment of chronic wounds. When wounds fail to achieve sufficient healing after 4 weeks of standard care, reassessment of underlying pathology and consideration of the need for advanced therapeutic agents should be undertaken. However, selection of an appropriate therapy is often not evidence based. Future Directions: Basic tenets of care need to be routinely followed, and a systematic evaluation of patients and their wounds will also facilitate appropriate care. Underlying pathologies, which result in the failure of these wounds to heal, differ among various types of chronic wounds. A better understanding of the differences between various types of chronic wounds at the molecular and cellular levels should improve our treatment approaches, leading to better healing rates, and facilitate the development of new more effective therapies. More evidence for the efficacy of current and future advanced wound therapies is required for their appropriate use.

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.