The science of wound bed preparation

Design Strategy of Microneedle Systems for Skin Wound Healing: Based on the Structure of Tips and Therapeutic Methodologies

The skin, being the largest organ of the human body, is susceptible to damage resulting in wounds that are vulnerable to pathogenic attacks and fail to provide effective protection for internal tissues. Therefore, it is crucial to expedite wound healing. In recent years, microneedles have garnered significant attention as an innovative drug delivery system owing to their noninvasive and painless administration, simplified application process, precise control over drug release, and versatile loading capabilities. Consequently, they hold immense potential for the treatment of skin wound. This review presents a comprehensive design strategy for the microneedle system in promoting skin wound healing. First, the process of skin wound healing and the characteristics of specific wounds are elucidated. The design strategies for microneedles are subsequently presented and classified based on their structural and therapeutic methodologies. Finally, a succinct recapitulation of the previously discussed points and a prospective analysis are provided.

Management of soft tissues in patients with periprosthetic joint infection

BACKGROUND

Appropriate soft tissue management represents a critical step in treating periprosthetic joint infection (PJI). This review discusses relevant guidelines that surgeons should follow in the management of soft tissues in PJI treatment. BODY: It is imperative for arthroplasty surgeons to thoroughly debride and rebuild soft tissue with a good blood supply. Relevant guidelines that surgeons should follow rigorously include preoperative evaluation of soft tissue status and plan-making, adequate surgical area exposure, intraoperative removal of all necrotic and infected soft tissues, adequate coverage of soft tissue defects, timely postoperative assessment and management of soft tissues, wound management and proper rehabilitation.

CONCLUSION

Soft tissue management plays a critical role in the treatment of PJI. To improve the infection control rate and postoperative joint function, surgeons should be familiar with these general principles and rigorously practice them in PJI management.

Disinfection capabilities of a 222 nm wavelength ultraviolet lighting device: a pilot study

OBJECTIVE

To demonstrate the efficacy of the SafeZone UVC (Ushio Inc., Japan) 222 nm ultraviolet C (UVC) light to reduce bacterial burden in pressure ulcers (PUs) in human patients. This research is the first human clinical trial using 222 nm UVC in eradicating bacteria in human wounds.

METHOD

Patients with Stage 2 or 3 (as defined by the revised National Pressure Ulcer Advisory Panel Pressure Injury Staging System) sacral or gluteal pressure ulcers (PUs) were subjected to four sessions of 222 nm UVC light therapy over two weeks. Pre- and post-UVC therapy, wound cultures were taken and quantitative analysis of bacterial colony forming units (CFU) were performed.

RESULTS

A total of 68 UV light sessions across 16 different patients were conducted. Of these sessions, 59 (87.0%) sessions showed a reduction in CFU counts, with 20 (29.4%) showing complete eradication of bacteria. Bacteria identified included meticillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella Pneumoniae. The overall median reduction in CFU of the 68 sessions was 78.9%. No adverse events were reported in any of the UV sessions.

CONCLUSION

In this study, 222 nm UVC light was safe and effective in reducing bacterial CFU counts in sacral and gluteal PUs across numerous different species of bacteria.

Contamination of wounds with fecal bacteria in immuno-suppressed mice

Immunocompromised patients are predisposed to chronically infected wounds. Especially ulcers in the dorsal region often experience secondary polymicrobial infections. However, current wound infection models mostly use single-strain bacteria. To mimic clinically occurring infections caused by fecal contamination in immunocompromised/immobile patients, which differ significantly from single-strain infections, the present study aimed at the establishment of a new mouse model using infection by fecal bacteria. Dorsal circular excision wounds in immunosuppressed mice were infected with fecal slurry solution in several dilutions up to 1:8,000. Impact of immunosuppressor, bacterial load and timing on development of wound infections was investigated. Wounds were analyzed by scoring, 3D imaging and swab analyses. Autofluorescence imaging was not successful. Dose-finding of cyclophosphamide-induced immunosuppression was necessary for establishment of bacterial wound infections. Infection with fecal slurry diluted 1:166 to 1:400 induced significantly delayed wound healing (p < 0.05) without systemic reactions. Swab analyses post-infection matched the initial polymicrobial suspension. The customized wound score confirmed significant differences between the groups (p < 0.05). Here we report the establishment of a simple, new mouse model for clinically occurring wound infections by fecal bacteria and the evaluation of appropriate wound analysis methods. In the future, this model will provide a suitable tool for the investigation of complex microbiological interactions and evaluation of new therapeutic approaches.

Bacterial-binding dressings in the management of wound healing and infection prevention: a narrative review

The aim of this review was to present the clinical data on the use of the family of bacterial-binding dressings (Sorbact; dialkylcarbamoyl chloride-coated) in the treatment of a variety of acute and chronic wounds. The findings are discussed in terms of the effectiveness of the bacterial-binding dressings on bacterial bioburden reduction, infection prevention, initiation/progression of wound healing and cost-effectiveness. The evidence in support of the bacterial-binding dressings is strongest in the area of infection prevention in surgical wounds, with several controlled trials showing the prophylactic benefit of the dressing in these wounds. Wound bioburden management in chronic wounds is supported by a number of clinical studies. In total, 29 published clinical studies (with a total of 4044 patients) were included in this review.

Bioimpedance Sensor Array for Long-Term Monitoring of Wound Healing from Beneath the Primary Dressings and Controlled Formation of H2O2 Using Low-Intensity Direct Current

Chronic wounds impose a significant financial burden for the healthcare system. Currently, assessment and monitoring of hard-to-heal wounds are often based on visual means and measuring the size of the wound. The primary wound dressings must be removed before assessment can be done. We have developed a quasi-monopolar bioimpedance-measurement-based method and a measurement system to determine the status of wound healing. The objective of this study was to demonstrate that with an appropriate setup, long-term monitoring of wound healing from beneath the primary dressings is feasible. The developed multielectrode sensor array was applied on the wound area and left under the primary dressings for 142 h. The impedance of the wounds and the surrounding intact skin area was measured regularly during the study at 150 Hz, 300 Hz, 1 kHz, and 5 kHz frequencies. At the end of the follow-up period, the wound impedance had reached the impedance of the intact skin at the higher frequencies and increased significantly at the lowest frequencies. The measurement frequency affected the measurement sensitivity in wound monitoring. The skin impedance remained stable over the measurement period. The sensor array also enabled the administration of periodical low-intensity direct current (LIDC) stimulation in order to create an antimicrobial environment across the wound area via the controlled formation of hydrogen peroxide (H₂O₂).

Use of negative pressure wound therapy with instillation and a reticulated open cell foam dressing with through holes in the acute care setting

Negative pressure wound therapy with instillation and dwell time (NPWTi-d) is an automated system used to deliver, dwell, and remove topical solutions from the wound bed. Recently, a reticulated open cell foam dressing with through holes (ROCF-CC) was developed, which assists with wound cleansing by removing thick exudate and infectious materials. We present our experience using NPWTi-d with ROCF-CC on complex wounds when complete surgical debridement was inappropriate because of medical instability, recurrent non-viable tissue, or palliative treatment plan. For all wounds, NPWTi-d with ROCF-CC was initiated by instilling normal saline, acetic acid, or hypochlorous acid with 2 to 10 minutes of dwell time, followed by 0.5 to 4 hours of negative pressure. Dressings were changed every 2 to 3 days. Fourteen patients with multiple comorbidities were treated for wound types including diabetic foot ulcers, necrotising fasciitis, dehisced wounds, and pressure injuries. Duration of NPWTi-d with ROCF-CC ranged from 1 to 15 days, and at dressing changes, wounds showed improved granulation tissue formation, less malodour, less surrounding erythema, and demarcation of healthy skin from devitalised tissue. Based on these patients, adjunctive use of NPWTi-d with ROCF-CC provided a practical option for improving tissue quality in wounds for patients in whom surgical debridement was not possible or desired.

Role of Topical Biological Therapies and Dressings in Healing Ischemic Wounds

Ischemic wounds are the most severe expression of critical limb ischemia (CLI), and they have been defined clinically as an end stage of peripheral arterial disease. Urgent revascularization is a fundamental part for limb salvage in patients with CLI. However, the risk of revascularization should be weighed against the likelihood of success given a patient’s life-threatening comorbidities. Once the condition of arterial insufficiency is revascularized, wound care is an important aspect to promote the wound healing process and infection control. MOIST concept for wound care is a modern systematic treatment for enhanced wound healing process. Currently, advanced biological therapies are emerging in ischemic wound therapies to restore the wound healing process and involve active biological agents to support the wound healing process. We studied and summarized the different types of available topical biological therapies and their mechanisms on the healing process including platelet-derived growth factor, epidermal growth factor, fibroblast growth factor, and vascular endothelial growth factor, platelet-rich plasma, and honey for local wound care of patient with CLI. Our review suggests that topical platelet-derived growth factor, epidermal growth factor, platelet-rich plasma, and honey are available as well as considered in the ischemic wound healing process enhancement through the MOIST concept. In conclusion, biologic wound dressing or topical agent therapy may improve the wound healing process, increase limb salvage, is inexpensive, and provides potential safety with nontoxic low-risk therapy in patients with an ischemic wound. Thus, local wound care by biological dressing should be added in adjuvant treatment for ischemic wound patients. However, further randomized studies are needed to support efficacy and long-term outcomes of these biological dressing in patients with ischemic wound.

Micelle-Coated, Hierarchically Structured Nanofibers with Dual-Release Capability for Accelerated Wound Healing and Infection Control

Tailoring nanofibrous matrices-a material with much promise for wound healing applications-to simultaneously mitigate bacterial colonization and stimulate wound closure of infected wounds is highly desirable. To that end, a dual-releasing, multiscale system of biodegradable electrospun nanofibers coated with biocompatible micellar nanocarriers is reported. For wound healing, transforming growth factor-β1 is incorporated into polycaprolactone/collagen (PCL/Coll) nanofibers via electrospinning and the myofibroblastic differentiation of human dermal fibroblasts is locally stimulated. To prevent infection, biocompatible nanocarriers of polypeptide-based block copolymer micelles are deposited onto the surfaces of PCL/Coll nanofibers using tannic acid as a binding partner. Micelle-modified fibrous scaffolds are favorable for wound healing, not only supporting the attachment and spreading of fibroblasts comparable to those on noncoated nanofibers, but also significantly enhancing fibroblast migration. Micellar coatings can be loaded with gentamicin or clindamycin and exhibit antibacterial activity as measured by Petrifilm and zone of inhibition assays as well as time-dependent reduction of cellular counts of Staphylococcus aureus cultures. Moreover, delivery time of antibiotic dosage is tunable through the application of a novel modular approach. Altogether, this system holds great promise as an infection-mitigating, cell-stimulating, biodegradable skin graft for wound management and tissue engineering.

Novel Multivalent Wound-Healing Ointment Provides Bioburden Control and Moisture Management: A Retrospective Registry Data Analysis

OBJECTIVE

The purpose of this retrospective registry data analysis was to explore the effectiveness of a novel multivalent topical ointment (Terrasil Infection Control Wound Care Ointment; Aspiera Medical, Woonsocket, Rhode Island), containing a patented mineral complex and 0.2% benzethonium chloride in the treatment of nonhealing acute and chronic wounds.

DESIGN

Aspiera Medical designed a registry to capture physician experiences and treatment results with Terrasil Infection Control Wound Care Ointment. Physicians were asked to enter deidentified patient data into an online registry.

SETTING

Wound clinics in the United States were asked to participate in the registry.

PATIENTS

Physicians at 4 wound clinics treated 30 patients (26 of whom completed the treatment) with various chronic wounds that had persisted for an average of 6 months and entered treatment data into the registry.

INTERVENTIONS

Patients applied the ointment according to physician orders. Concurrent treatments used by patients included offloading, compression wraps, and dressings, such as collagen and calcium alginate. Patients were treated until complete wound closure or lost to follow-up.

MAIN OUTCOME MEASURES

Physicians calculated each patient's percentage wound reduction at each visit.

MAIN RESULTS

Thirty patients were entered into the registry. Pretreatment and posttreatment measurements were available for 26 of them. Patients achieved an average surface area reduction of 84% in a mean of 23 days' treatment.

CONCLUSION

The antimicrobial and moisturizing ointment studied appears to be effective in promoting wound closure in a variety of acute and chronic wounds. Wounds studied included diabetic foot ulcers, venous leg ulcers, venous stasis ulcers, surgical infections, burns, and insect bites. The results of this registry data analysis will be used to inform planned clinical trials.

Bioimpedance measurement based evaluation of wound healing

OBJECTIVE

Our group has developed a bipolar bioimpedance measurement-based method for determining the state of wound healing. The objective of this study was to assess the capability of the method.

METHODS

To assess the performance of the method, we arranged a follow-up study of four acute wounds. The wounds were measured using the method and photographed throughout the healing process.

RESULTS

Initially the bioimpedance of the wounds was significantly lower than the impedance of the undamaged skin, used as a baseline. Gradually, as healing progressed, the wound impedance increased and finally reached the impedance of the undamaged skin.

CONCLUSION

The clinical appearance of the wounds examined in this study corresponded well with the parameters derived from the bioimpedance data.

SIGNIFICANCE

Hard-to-heal wounds are a significant and growing socioeconomic burden, especially in the developed countries, due to aging populations and to the increasing prevalence of various lifestyle related diseases. The assessment and the monitoring of chronic wounds are mainly based on visual inspection by medical professionals. The dressings covering the wound must be removed before assessment; this may disturb the wound healing process and significantly increases the work effort of the medical staff. There is a need for an objective and quantitative method for determining the status of a wound without removing the wound dressings. This study provided evidence of the capability of the bioimpedance based method for assessing the wound status. In the future measurements with the method should be extended to concern hard-to-heal wounds.

National Athletic Trainers' Association Position Statement: Management of Acute Skin Trauma

OBJECTIVE

  To present recommendations for the cleansing, debridement, dressing, and monitoring of acute skin trauma in patients.

BACKGROUND

  Acute skin trauma is common during participation in athletic and recreational activities. Clinical decisions and intervention protocols after injury vary among athletic trainers and are often based on ritualistic practices. An understanding of cleansing, debridement, and dressing techniques; clinical features of infection and adverse reactions; and monitoring of acute skin trauma is critical for certified athletic trainers and other allied health and medical professionals to create a local wound environment that promotes healing and lessens the risk of complications.

RECOMMENDATIONS

  These guidelines are intended to provide the certified athletic trainer and others participating in athletic health care with specific knowledge about and recommendations for the management of acute skin trauma.

Skin substitutes based on allogenic fibroblasts or keratinocytes for chronic wounds not responding to conventional therapy: a retrospective observational study

Chronic wounds are an expression of underlying complex pathologies and have a high incidence. Skin substitutes may represent an alternative approach to treat chronic ulcers. The aim of this retrospective observational study was to evaluate the wound reduction using skin substitutes based on allogenic fibroblasts or keratinocytes in 30 patients not responding to conventional therapy. Wound bed was prepared, then keratinocytes on Laserskin(®) to treat superficial wounds or fibroblasts on Hyalograft 3D(R) to treat deep leg ulcers were applied, and finally wounds were treated with a secondary dressing composed of nanocrystalline silver. Once a week constructs were removed and new bioengineered products were applied, as well as nanocrystalline silver medication. In none of the cases under examination did any complications arise relating to the treatment. We also achieved a reduction in wound dimension and exudates, and an increase in wound bed score. Postoperative assessment shows a degree of healing that is statistically higher in the group treated with keratinocytes as compared with the fibroblast group. This retrospective study improves our understanding and defines the clinical indications for the various uses of the two types of skin substitutes.

Polyvinyl pyrrolidone/carrageenan blend hydrogels with nanosilver prepared by gamma radiation for use as an antimicrobial wound dressing

Hydrogels were prepared using polyvinyl pyrrolidone (PVP) blended with carrageenan by gamma irradiation at different doses of 25 and 40 kGy. Gel fraction of hydrogels prepared using 10 and 15% PVP in combination with 0.25 and 0.5% carrageenan was evaluated. Based on gel fraction, 15% PVP in combination with 0.25% carrageenan and radiation dose of 25 kGy was selected for the preparation of hydrogels with nanosilver. Radiolytic synthesis of silver nanoparticles within the PVP hydrogel was carried out. The hydrogels with silver nanoparticles were assessed for antimicrobial effectiveness and physical properties of relevance to clinical performance. Fluid handling capacity (FHC) for PVP/carrageenan was 2.35 ± 0.39-6.63 ± 0.63 g/10 cm(2) in 2-24 h. No counts for Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans were observed in the presence of hydrogels containing 100 ppm nanosilver after 3-6 h. The release of silver from hydrogels containing 100 ppm nanosilver was 20.42 ± 1.98 ppm/100 cm(2) in 24 h. Hydrogels containing 100 ppm nanosilver with efficient FHC demonstrated potential microbicidal activity (≥3 log10 decrease in CFU/ml) against wound pathogens, P. aeruginosa, S. aureus, E. coli, and C. albicans. PVP/carrageenan hydrogels containing silver nanoparticles can be used as wound dressings to control infection and facilitate the healing process for burns and other skin injuries.

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.

Optimizing Wound Bed Preparation With Collagenase Enzymatic Debridement

Difficult-to-heal and chronic wounds affect tens of millions of people worldwide. In the U.S. alone, the direct cost for their treatment exceeds $25 billion. Yet despite advances in wound research and treatment that have markedly improved patient care, wound healing is often delayed for weeks or months. For venous and diabetic ulcers, complete wound closure is achieved in as few as 25%-50% of chronic or hard-to-heal wounds. Wound bed preparation and the consistent application of appropriate and effective debridement techniques are recommended for the optimized treatment of chronic wounds. The TIME paradigm (Tissue, Inflammation/infection, Moisture balance and Edge of wound) provides a model to remove barriers to healing and optimize the healing process. While we often think of debridement as an episodic event that occurs in specific care giver/patient interface. There is the possibility of a maintenance debridement in which the chronic application of a medication can assist in both the macroscopic and microscopic debridement of a wound. We review the various debridement therapies available to clinicians in the United States, and explore the characteristics and capabilities of clostridial collagenase ointment (CCO), a type of enzymatic debridement, that potentially allows for epithelialization while debriding. It appears that in the case of CCO it may exert this influences by removal of the necrotic plug while promoting granulation and sustaining epithelialization. It is also easily combined with other methods of debridement, is selective to necrotic tissue, and has been safely used in various populations. We review the body of evidence has indicated that this concept of maintenance debridement, especially when combined episodic debridement may add a cost an efficacious, safe and cost-effective choice for debridement of cutaneous ulcers and burn wounds and it will likely play an expanding role in all phases of wound bed preparation.

Low-grade elastic compression regimen for venous leg ulcers--an effective compromise for patients requiring daily dressing changes

Venous leg ulcers (VLUs) affect millions of patients worldwide and are a tremendous financial burden on our health care system. The hallmark of venous disease of the lower extremities is venous hypertension, and compression is the current mainstay of treatment. However, many patients are non-compliant, partly because of the complexity of the dressings and the difficulties with application and removal. The aim of our study was to test an effective compression dressing regimen for patients with VLUs who require changing the ulcer primary dressing twice daily. We used two layers of a latex-free tubular elastic bandage for compression. The primary endpoint of our study was increased wound-healing rate and our secondary endpoint was complete wound closure. All active study subjects had positive healing rates at week 4 and week 8. Two subjects achieved complete wound closure by week 8. We conclude that compression with a latex-free tubular elastic bandage can be safely used in patients with VLUs requiring frequent dressing changes. This type of compression allows for daily inspection of wounds, dressing changes at home, flexibility in the context of clinical trials, and is a compromise for patients who are intolerant to compression dressings.

The emerging use of bone marrow-derived mesenchymal stem cells in the treatment of human chronic wounds

INTRODUCTION

Close to 5 million people in the USA are affected by chronic wounds, and billions of dollars are spent annually for their treatment. Despite advances in chronic wound management over the past decades, many patients afflicted with chronic wounds fail to heal or their ulcers recur. There is emerging evidence that the use of bone marrow-derived mesenchymal stem cells (BM-MSCs) can offset this situation of impaired healing.

AREAS COVERED

This article provides a review of the use of BM-MSC for the treatment of chronic wounds, the current development of stem cell delivery to chronic wounds and related challenges are also described in this manuscript.

EXPERT OPINION

Numerous animal studies and a few pilot studies in human wounds have shown that BM-MSC can augment wound closure. Still, the primary contribution of mesenchymal stem cells (MSCs) to cutaneous regeneration and the long-term systemic effects of MSCs are yet to be established. In addition, we need to determine whether other types of stem/progenitor cells will be more effective. Therefore, more randomized controlled clinical trials need to be undertaken. It is of importance to remember that even with the most advanced and sophisticated therapeutic approaches, proper wound care and adherence to basic principles remain critical.

First evidence of sternal wound biofilm following cardiac surgery

Management of deep sternal wound infection (SWI), a serious complication after cardiac surgery with high morbidity and mortality incidence, requires invasive procedures such as, debridement with primary closure or myocutaneous flap reconstruction along with use of broad spectrum antibiotics. The purpose of this clinical series is to investigate the presence of biofilm in patients with deep SWI. A biofilm is a complex microbial community in which bacteria attach to a biological or non-biological surface and are embedded in a self-produced extracellular polymeric substance. Biofilm related infections represent a major clinical challenge due to their resistance to both host immune defenses and standard antimicrobial therapies. Candidates for this clinical series were patients scheduled for a debridement procedure of an infected sternal wound after a cardiac surgery. Six patients with SWI were recruited in the study. All cases had marked dehiscence of all layers of the wound down to the sternum with no signs of healing after receiving broad spectrum antibiotics post-surgery. After consenting patients, tissue and/or extracted stainless steel wires were collected during the debridement procedure. Debrided tissues examined by Gram stain showed large aggregations of Gram positive cocci. Immuno-fluorescent staining of the debrided tissues using a specific antibody against staphylococci demonstrated the presence of thick clumps of staphylococci colonizing the wound bed. Evaluation of tissue samples with scanning electron microscope (SEM) imaging showed three-dimensional aggregates of these cocci attached to the wound surface. More interestingly, SEM imaging of the extracted wires showed attachment of cocci aggregations to the wire metal surface. These observations along with the clinical presentation of the patients provide the first evidence that supports the presence of biofilm in such cases. Clinical introduction of the biofilm infection concept in deep SWI may advance the current management strategies from standard antimicrobial therapy to anti-biofilm strategy.

Local delivery of allogeneic bone marrow and adipose tissue-derived mesenchymal stromal cells for cutaneous wound healing in a porcine model

Wound healing remains a major challenge in modern medicine. Bone marrow- (BM) and adipose tissue- (AT) derived mesenchymal stromal/stem cells (MSCs) are of great interest for tissue reconstruction due to their unique immunological properties and regenerative potential. The purpose of this study was to characterize BM and AT-MSCs and evaluate their effect when administered in a porcine wound model. MSCs were derived from male Göttingen Minipigs and characterized according to established criteria. Allogeneic BM- or AT-MSCs were administered intradermally (1 x 10(6) cells) into partial-thickness wounds created on female animals, and covered with Vaseline® gauze or fibrin in a randomized pattern. Animals were euthanized at 7, 10, 14 and 21 days. Tissues were analyzed visually for healing and by microscopic examination for epidermal development and remodelling. Polymerase chain reaction (PCR) was used to detect the presence of male DNA in the specimens. All wounds were healed by 14 days. MSC-injected wounds were associated with improved appearance and faster re-epithelialization compared to saline controls. Evaluation of rete ridge depth and architecture showed that MSC treatment promoted a faster rate of epidermal maturation. Male DNA was detected in all samples at days 7 and 10, suggesting the presence of MSCs. We showed the safety, feasibility and potential efficacy of local injection of allogeneic BM- and AT-MSCs for treatment of wounds in a preclinical model. Our data in this large animal model support the potential use of BM- and AT-MSC for treatment of cutaneous wounds through modulation of healing and epithelialization.

Wound bed preparation for chronic diabetic foot ulcers

The escalating incidence of diabetic mellitus has given rise to the increasing problems of chronic diabetic ulcers that confront the practice of medicine. Peripheral vascular disease, neuropathy, and infection contribute to the multifactorial pathogenesis of diabetic ulcers. Approaches to the management of diabetic ulcers should start with an assessment and optimization of the patient's general conditions, followed by considerations of the local and regional factors. This paper aims to address the management strategies for wound bed preparation in chronic diabetic foot ulcers and also emphasizes the importance of preventive measures and future directions. The “TIME” framework in wound bed preparation encompasses tissue management, inflammation and infection control, moisture balance, and epithelial (edge) advancement. Tissue management aims to remove the necrotic tissue burden via various methods of debridement. Infection and inflammation control restores bacterial balance with the reduction of bacterial biofilms. Achieving a moist wound healing environment without excessive wound moisture or dryness will result in moisture balance. Epithelial advancement is promoted via removing the physical and biochemical barriers for migration of epithelium from wound edges. These systematic and holistic approaches will potentiate the healing abilities of the chronic diabetic ulcers, including those that are recalcitrant.

Wound bed preparation from a clinical perspective

Wound bed preparation has been performed for over two decades, and the concept is well accepted. The ‘TIME’ acronym, consisting of tissue debridement, infection or inflammation, moisture balance and edge effect, has assisted clinicians systematically in wound assessment and management. While the focus has usually been concentrated around the wound, the evolving concept of wound bed preparation promotes the treatment of the patient as a whole. This article discusses wound bed preparation and its clinical management components along with the principles of advanced wound care management at the present time. Management of tissue necrosis can be tailored according to the wound and local expertise. It ranges from simple to modern techniques like wet to dry dressing, enzymatic, biological and surgical debridement. Restoration of the bacterial balance is also an important element in managing chronic wounds that are critically colonized. Achieving a balance moist wound will hasten healing and correct biochemical imbalance by removing the excessive enzymes and growth factors. This can be achieved will multitude of dressing materials. The negative pressure wound therapy being one of the great breakthroughs. The progress and understanding on scientific basis of the wound bed preparation over the last two decades are discussed further in this article in the clinical perspectives.

Mesenchymal Stem Cells: A Multimodality Option for Wound Healing

BACKGROUND

Although significant resources are invested in wound care and healing annually, chronic wounds remain a major medical problem as they often present a more difficult challenge than the underlying disease. Current treatment options include a multitude of dressing materials, topical agents including antibiotics, enzymatic debriders, and growth factors, mechanical debridement, and optimization of medical comorbidities.

THE PROBLEM

Even under optimal circumstances, the healing process leads to some form of fibrosis and scarring.

BASIC/CLINICAL SCIENCE ADVANCES

Studies suggest that mesenchymal stem/stromal cells (MSCs) isolated from these diverse tissues possess similar biological characteristics, differentiation potential, and immunological properties. Enthusiasm about MSCs for use in reconstruction and regenerative medicine has been fueled by evidence that these cells possess the ability to participate in the tissue repair process through a variety of paracrine mechanisms affecting tissue regeneration and inflammation.

CLINICAL CARE RELEVANCE

Recent advances in stem cell immunobiology have led to increased interest in MSCs as a new therapeutic modality to address chronic wounds and other inflammatory pathology.

CONCLUSION

A thorough understanding of the immunobiology of MSCs is necessary to realize the complement of pathological processes that could be affected by MSC-based therapy. The novel methods reviewed here are highly promising, with the collective goal of identifying new therapeutic approaches to wound healing that are broadly applicable to many chronic diseases, and can safely accelerate the transition of basic research findings into clinical advances in many areas of regenerative medicine and reconstructive surgery.

Unusual causes of cutaneous ulceration

Skin ulceration is a major source of morbidity and is often difficult to manage. Ulcers caused by an inflammatory cause or microvascular occlusion are particularly challenging in terms of diagnosis and treatment. The management of such ulcers requires careful assessment of associated systemic conditions and a thorough analysis of the ulcer's clinical and histologic findings. In this article, the authors discuss several examples of inflammatory ulcers and the approach to the diagnosis and treatment of these ulcers.

A Randomized Controlled Trial to Examine the Efficacy and Safety of a New Super-Oxidized Solution for the Management of Wide Postsurgical Lesions of the Diabetic Foot

This randomized trial was done to test the effectiveness and safety of using a novel antiseptic solution (Dermacyn® Wound Care [DWC], Oculus Innovative Sciences, Petaluma, CA) in the management of the postoperative lesions on the infected diabetic foot. 40 patients with postsurgical lesions wider than 5 cm2 left open to heal by secondary intention were randomized into 2 groups. Group A was locally treated with DWC, whereas group B received povidone iodine as local medication, both in adjunct to systemic antibiotic therapy and surgical debridement if needed. Ischemia, renal failure, bilateral lesions, or immunodepression were considered as exclusion criteria. Patients were followed up weekly for 6 months. The primary endpoint was healing rate at 6 months, while secondary endpoints were healing time, time to achieve negative cultures, duration of antibiotic therapy, number of reinterventions, and adverse events. Healing rates at 6 months were significantly shorter in group A (90%) than in group B (55%; P < .01). The time taken for cultures to become negative and duration of antibiotic therapy were also significantly (P < .05) shorter in group A than in group B, whereas the number of reinterventions was significantly higher in group B (P < .05). No difference was noted in the adverse events except that for reinfections, which were more frequent in group B than in group A (P < .01). DWC is as safe as and more effective than standard local antiseptics in the management of wide postsurgical lesions in the infected diabetic foot.

Mesenchymal stem cell therapy for nonhealing cutaneous wounds

SUMMARY

Chronic wounds remain a major challenge in modern medicine and represent a significant burden, affecting not only physical and mental health, but also productivity, health care expenditure, and long-term morbidity. Even under optimal conditions, the healing process leads to fibrosis or scar. One promising solution, cell therapy, involves the transplantation of progenitor/stem cells to patients through local or systemic delivery, and offers a novel approach to many chronic diseases, including nonhealing wounds. Mesenchymal stem cells are multipotent, adult progenitor cells of great interest because of their unique immunologic properties and regenerative potential. A variety of preclinical and clinical studies have shown that mesenchymal stem cells may have a useful role in wound-healing and tissue-engineering strategies and both aesthetic and reconstructive surgery. Recent advances in stem cell immunobiology can offer insight into the multiple mechanisms through which mesenchymal stem cells could affect underlying pathophysiologic processes associated with nonhealing mesenchymal stem cells. Critical evaluation of the current literature is necessary for understanding how mesenchymal stem cells could potentially revolutionize our approach to skin and soft-tissue defects and designing clinical trials to address their role in wound repair and regeneration.

Wound healing in older adults

Chronic wounds affect a substantial number of individuals throughout the world, and impose a significant psychological, physical and economic burden. As the population ages, the incidence of chronic wounds is also expected to rise. Clinicians struggle to find the optimal approaches to prevention and treatment of these nonhealing or slow-healing wounds. This review discusses current best practices and evidence-based recommendations for preventing and managing chronic wounds in general, as well as pressure ulcers, diabetic foot ulcers and venous leg ulcers specifically. This review highlights the significant gaps and inconsistencies in the current evidence base for chronic wound care, which have hindered making substantial progress in improving wound healing rates. It concludes with recommendations for improving the research and clinical knowledge base related to optimal wound-care practices.

A review of tissue-engineered skin bioconstructs available for skin reconstruction

Situations where normal autografts cannot be used to replace damaged skin often lead to a greater risk of mortality, prolonged hospital stay and increased expenditure for the National Health Service. There is a substantial need for tissue-engineered skin bioconstructs and research is active in this field. Significant progress has been made over the years in the development and clinical use of bioengineered components of the various skin layers. Off-the-shelf availability of such constructs, or production of sufficient quantities of biological materials to aid rapid wound closure, are often the only means to help patients with major skin loss. The aim of this review is to describe those materials already commercially available for clinical use as well as to give a short insight to those under development. It seeks to provide skin scientists/tissue engineers with the information required to not only develop in vitro models of skin, but to move closer to achieving the ultimate goal of an off-the-shelf, complete full-thickness skin replacement.

Hypoxia-enhanced wound-healing function of adipose-derived stem cells: increase in stem cell proliferation and up-regulation of VEGF and bFGF

Adipose-derived stem cells (ADSCs) have been shown to induce wound-healing effects. Because inflammation near the wound area induces oxygen deficiency, it is interesting to elucidate the effect of hypoxia on the function of ADSCs. In this work, we asked: (1) does hypoxia alter the wound-healing function of ADSCs? and (2) what are the major factors responsible for the alteration in the wound-healing function? Effect of hypoxia on the proliferation of ADSCs was first examined that hypoxia (2% O(2)) enhanced the proliferation of ADSCs in either the presence of serum or in the absence of serum. The conditioned medium of ADSCs harvested under hypoxia (hypoCM) significantly promoted collagen synthesis and the migration of human dermal fibroblasts, compared with that in normoxia (norCM). In the animal studies, hypoCM significantly reduced the wound area compared with norCM. Furthermore, mRNA and protein measurements showed that hypoxia up-regulated growth factors such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Inhibition of VEGF and bFGF using neutralizing antibodies reversed the migration of the wounded human dermal fibroblasts and the healing of wounds in animal experiment. Collectively, these results suggest that hypoxia increases the proliferation of ADSCs and enhances the wound-healing function of ADSCs, at least partly, by up-regulating the secretion of VEGF and bFGF.