Chronic wounds

Burden of Chronic Nonhealing Wounds: An Overview of the Worldwide Humanistic and Economic Burden to the Healthcare System

Chronic wounds have long been a significant public health concern, but the true impact of these wounds is unknown since research designs and measuring techniques vary, leading to inconsistent estimates. The definition of a wound is a loss of epithelial continuity caused by damage to the tissue. The following conditions can cause chronic wounds: panniculitis, pyoderma gangrenosum, traumatic, neurological, metabolic, hematologic, neoplastic, or infection-related. The growing global incidence of diabetes and the aging population necessitate greater attention to chronic wounds. Regrettably, it is sad that significant healthcare institutions have overlooked wound research. The study of health-related illnesses and occurrences in particular populations, including their distribution, frequency, and determinants, and the application of this research to control health problems.

Enhanced wound healing and hemostasis with exosome-loaded gelatin sponges from human umbilical cord mesenchymal stem cells

BACKGROUND

Rapid wound healing remains a pressing clinical challenge, necessitating studies to hasten this process. A promising approach involves the utilization of human umbilical cord mesenchymal stem cells (hUC-MSCs) derived exosomes. The hypothesis of this study was that these exosomes, when loaded onto a gelatin sponge, a common hemostatic material, would enhance hemostasis and accelerate wound healing.

AIM

To investigate the hemostatic and wound healing efficacy of gelatin sponges loaded with hUC-MSCs-derived exosomes.

METHODS

Ultracentrifugation was used to extract exosomes from hUC-MSCs. Nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and western blot techniques were used to validate the exosomes. In vitro experiments were performed using L929 cells to evaluate the cytotoxicity of the exosomes and their impact on cell growth and survival. New Zealand rabbits were used for skin irritation experiments to assess whether they caused adverse skin reactions. Hemolysis test was conducted using a 2% rabbit red blood cell suspension to detect whether they caused hemolysis. Moreover, in vivo experiments were carried out by implanting a gelatin sponge loaded with exosomes subcutaneously in Sprague-Dawley (SD) rats to perform biocompatibility tests. In addition, coagulation index test was conducted to evaluate their impact on blood coagulation. Meanwhile, SD rat liver defect hemostasis model and full-thickness skin defect model were used to study whether the gelatin sponge loaded with exosomes effectively stopped bleeding and promoted wound healing.

RESULTS

The NTA, TEM, and western blot experimental results confirmed that exosomes were successfully isolated from hUC-MSCs. The gelatin sponge loaded with exosomes did not exhibit significant cell toxicity, skin irritation, or hemolysis, and they demonstrated good compatibility in SD rats. Additionally, the effectiveness of the gelatin sponge loaded with exosomes in hemostasis and wound healing was validated. The results of the coagulation index experiment indicated that the gelatin sponge loaded with exosomes had significantly better coagulation effect compared to the regular gelatin sponge, and they showed excellent hemostatic performance in a liver defect hemostasis model. Finally, the full-thickness skin defect healing experiment results showed significant improvement in the healing process of wounds treated with the gelatin sponge loaded with exosomes compared to other groups.

CONCLUSION

Collectively, the gelatin sponge loaded with hUC-MSCs-derived exosomes is safe and efficacious for promoting hemostasis and accelerating wound healing, warranting further clinical application.

Different Curcumin-Loaded Delivery Systems for Wound Healing Applications: A Comprehensive Review

Curcumin or turmeric is the active constituent of Curcuma longa L. It has marvelous medicinal applications in many diseases. When the skin integrity is compromised due to either acute or chronic wounds, the body initiates several steps leading to tissue healing and skin barrier function restoration. Curcumin has very strong antibacterial and antifungal activities with powerful wound healing ability owing to its antioxidant activity. Nevertheless, its poor oral bioavailability, low water solubility and rapid metabolism limit its medical use. Tailoring suitable drug delivery systems for carrying curcumin improves its pharmaceutical and pharmacological effects. This review summarizes the most recent reported curcumin-loaded delivery systems for wound healing purposes, chiefly hydrogels, films, wafers, and sponges. In addition, curcumin nanoformulations such as nanohydrogels, nanoparticles and nanofibers are also presented, which offer better solubility, bioavailability, and sustained release to augment curcumin wound healing effects through stimulating the different healing phases by the aid of the small carrier.

Chronic wounds

Chronic wounds are characterized by their inability to heal within an expected time frame and have emerged as an increasingly important clinical problem over the past several decades, owing to their increasing incidence and greater recognition of associated morbidity and socio-economic burden. Even up to a few years ago, the management of chronic wounds relied on standards of care that were outdated. However, the approach to these chronic conditions has improved, with better prevention, diagnosis and treatment. Such improvements are due to major advances in understanding of cellular and molecular aspects of basic science, in innovative and technological breakthroughs in treatment modalities from biomedical engineering, and in our ability to conduct well-controlled and reliable clinical research. The evidence-based approaches resulting from these advances have become the new standard of care. At the same time, these improvements are tempered by the recognition that persistent gaps exist in scientific knowledge of impaired healing and the ability of clinicians to reduce morbidity, loss of limb and mortality. Therefore, taking stock of what is known and what is needed to improve understanding of chronic wounds and their associated failure to heal is crucial to ensuring better treatments and outcomes.

Preclinical safety of negatively charged microspheres (NCMs): optimization of radiolabeling for in vivo and ex vivo biodistribution studies after topical administration on full-thickness wounds in a rat model

Negatively charged microspheres (NCMs) are postulated as a new form of treatment for chronic wounds. Despite the efficacy shown at clinical level, more studies are required to demonstrate their safety and local effect. The objective of the work was to confirm the lack of NCM systemic absorption performing a biodistribution study of the NCMs in an open wound rat animal model. To this end, radiolabeling of NCMs with technetium-99m was optimized and biodistribution studies were performed by in vivo SPEC/CT imaging and ex vivo counting during 24 h after topical administration. The studies were performed on animals treated with a single or repeated dose to study the effect of macrophages during a prolonged treatment. NCM radiolabeling was achieved in a simple, efficient and stable manner with high yield. SPECT/CT images showed that almost all NCMs (about 85 %) remained on the wound for 24 h either after single or multiple administrations. Ex vivo biodistribution studies confirmed that there was no accumulation of NCMs in any organ or tissue except in the wound area, suggesting a lack of absorption. In conclusion, NCMs can be considered safe as local wound treatment since they remain at the administration area.

Cationic, anionic and neutral polysaccharides for skin tissue engineering and wound healing applications

Today, chronic wound care and management can be regarded as a clinically critical issue. However, the limitations of current approaches for wound healing have encouraged researchers and physicians to develop more efficient alternative approaches. Advances in tissue engineering and regenerative medicine have resulted in the development of promising approaches that can accelerate wound healing and improve the skin regeneration rate and quality. The design and fabrication of scaffolds that can address the multifactorial nature of chronic wound occurrence and provide support for the healing process can be considered an important area requiring improvement. In this regard, polysaccharide-based scaffolds have distinctive properties such as biocompatibility, biodegradability, high water retention capacity and nontoxicity, making them ideal for wound healing applications. Their tunable structure and networked morphology could facilitate a number of functions, such as controlling their diffusion, maintaining wound moisture, absorbing a large amount of exudates and facilitating gas exchange. In this review, the wound healing process and the influential factors, structure and properties of carbohydrate polymers, physical and chemical crosslinking of polysaccharides, scaffold fabrication techniques, and the use of polysaccharide-based scaffolds in skin tissue engineering and wound healing applications are discussed.

Integrated Multiplex Sensing Bandage for In Situ Monitoring of Early Infected Wounds

Infection, the most common complication of chronic wounds, has placed tremendous burden on patients and society. Existing care strategies could hardly reflect in situ wound status, resulting in overly aggressive or conservative therapeutic options. Multiplexed tracking of wound markers to obtain diagnostic information in a more accurate way is highly promising and in great demand for the emerging development of personalized medicine. Here, an integrated multiplex sensing bandage (MSB) system, including a multiplex sensor array (MSA), a corresponding flexible circuit, and a mobile application, was developed for real-time monitoring of sodium, potassium, calcium, pH, uric acid, and temperature indicators in the wound site to provide a quantitative diagnostic basis. The MSB was optimized for wound-oriented management applications, which exhibits a broad linear response, excellent selectivity, temporal stability, mechanical stability, reproducibility, and reliable signal transmission performance on the aforementioned physiological indicators. The results of in vivo experiments demonstrate that the MSA is capable of real-time monitoring of actual wounds as well as early prediction of infection. The results ultimately point to the potential clinical applicability of the MSB, which might benefit the quantifications of the complexity and diversity of the wound healing process. This work provides a unique strategy that holds promise for broad application in optimizing wound management and even coping with other diseases.

Comparison of Postsurgical Scars Between Vegan and Omnivore Patients

BACKGROUND

Postsurgical skin healing can result in different scars types, ranging from a fine line to pathologic scars, in relation to patients' intrinsic and extrinsic factors. Although the role of nutrition in influencing skin healing is known, no previous studies investigated if the vegan diet may affect postsurgical wounds.

OBJECTIVE

The aim of this study was to compare surgical scars between omnivore and vegan patients.

METHODS AND MATERIALS

This is a prospective observational study. Twenty-one omnivore and 21 vegan patients who underwent surgical excision of a nonmelanoma skin cancer were enrolled. Postsurgical complications and scar quality were evaluated using the modified Scar Cosmesis Assessment and Rating (SCAR) scale.

RESULTS

Vegans showed a significantly lower mean serum iron level (p < .001) and vitamin B12 (p < .001). Wound diastasis was more frequent in vegans (p = .008). After 6 months, vegan patients had a higher modified SCAR score than omnivores (p < .001), showing the worst scar spread (p < .001), more frequent atrophic scars (p < .001), and worse overall impression (p < .001).

CONCLUSION

This study suggests that a vegan diet may negatively influence the outcome of surgical scars.

Decellularized Scaffolds for Skin Repair and Regeneration

The skin is the largest organ in the body, fulfilling a variety of functions and acting as a barrier for internal organs against external insults. As for extensive or irreversible damage, skin autografts are often considered the gold standard, however inherent limitations highlight the need for alternative strategies. Engineering of human-compatible tissues is an interdisciplinary and active field of research, leading to the production of scaffolds and skin substitutes to guide repair and regeneration. However, faithful reproduction of extracellular matrix (ECM) architecture and bioactive content capable of cell-instructive and cell-responsive properties remains challenging. ECM is a heterogeneous, connective network composed of collagens, glycoproteins, proteoglycans, and small molecules. It is highly coordinated to provide the physical scaffolding, mechanical stability, and biochemical cues necessary for tissue morphogenesis and homeostasis. Decellularization processes have made it possible to isolate the ECM in its native and three-dimensional form from a cell-populated tissue for use in skin regeneration. In this review, we present recent knowledge about these decellularized biomaterials with the potential to be used as dermal or skin substitutes in clinical applications. We detail tissue sources and clinical indications with success rates and report the most effective decellularization methods compatible with clinical use.

Enhanced wound healing via collagen-turnover-driven transfer of PDGF-BB gene in a murine wound model

Wound healing is a complex biological process that requires coordinated cell proliferation, migration, and extracellular matrix production/remodeling, all of which are inhibited/delayed in chronic wounds. In this study, a formulation was developed that marries a fibrin-based, provisional-like matrix with collagen mimetic peptide (CMP)/PDGF gene-modified collagens, leading to the formation of robust gels that supported temporally controlled PDGF expression and facile application within the wound bed. Analysis employing in vitro co-gel scaffolds confirmed sustained and temporally controlled gene release based on matrix metalloproteinase (MMP) activity, with ~30% higher PDGF expression in MMP producing fibroblasts as-compared with non-MMP-expressing cells. The integration of fibrin with the gene-modified collagens resulted in co-gels that strongly supported both fibroblast cell recruitment/invasion as well as multiple aspects of the longer-term healing process. The excisional wound healing studies in mice established faster wound closure using CMP-modified PDGF polyplex-loaded co-gels, which exhibited up to 24% more wound closure (achieved with ~2 orders of magnitude lower growth factor dosing) after 9 days as compared to PDGF-loaded co-gels, and 19% more wound closure after 9 days as compared to CMP-free polyplex loaded co-gels. Moreover, minimal scar formation as well as improved collagen production, myofibroblast activity, and collagen orientation was observed following CMP-modified PDGF polyplex-loaded co-gel application on wounds. Taken together, the combined properties of the co-gels, including their stability and capacity to control both cell recruitment and cell phenotype within the murine wound bed, strongly supports the potential of the co-gel scaffolds for improved treatment of chronic non-healing wounds.

Design Considerations for Hydrogel Wound Dressings: Strategic and Molecular Advances

Wound dressings are traditionally used to protect a wound and to facilitate healing. Currently, their function is expanding. There is an urgent need for new smart products that not only act as a protective barrier but also actively support the wound healing process. Hydrogel dressings are an example of such innovative products and typically facilitate wound healing by providing a hospitable and moist environment in which cells can thrive, while the wound can still breathe and exudate can be drained. These dressings also tend to be less painful or have a soothing effect and allow for additional drug delivery. In this review, various strategic and molecular design considerations are discussed that are relevant for developing a hydrogel into a wound dressing product. These considerations vary from material choice to ease of use and determine the dressing's final properties, application potential, and benefits for the patient. The focus of this review lies on identifying and explaining key aspects of hydrogel wound dressings and their relevance in the different phases of wound repair. Molecular targets of wound healing are discussed that are relevant when tailoring hydrogels toward specific wound healing scenarios. In addition, the potential of hydrogels is reviewed as medicine advances from a repair-based wound healing approach toward a regenerative-based one. Hydrogels can play a key role in the transition toward personal wound care and facilitating regenerative medicine strategies by acting as a scaffold for (stem) cells and carrier/source of bioactive molecules and/or drugs. Impact statement Improved wound healing will lead to a better quality of life around the globe. It can be expected that this coincides with a reduction in health care spending, as the duration of treatment decreases. To achieve this, new and modern wound care products are desired that both facilitate healing and improve comfort and outcome for the patient. It is proposed that hydrogel wound dressings can play a pivotal role in improving wound care, and to that end, this review aims to summarize the various design considerations that can be made to optimize hydrogels for the purpose of a wound dressing.

Topical antimicrobial peptide formulations for wound healing: Current developments and future prospects

Antimicrobial peptides (AMPs) are the natural antibiotics recognized for their potent antibacterial and wound healing properties. Bare AMPs have limited activity following topical application attributable to their susceptibility to environment (hydrolysis, oxidation, photolysis), and wound (alkaline pH, proteolysis) related factors as well as minimal residence time. Therefore, the formulation of AMPs is essential to enhance stability, prolong delivery, and optimize effectiveness at the wound site. Different topical formulations of AMPs have been developed so far including nanoparticles, hydrogels, creams, ointments, and wafers to aid in controlling bacterial infection and enhance wound healing process in vivo. Herein, an overview is provided of the AMPs and current understanding of their formulations for topical wound healing applications along with suitable examples. Furthermore, future prospects for the development of effective combination AMP formulations are discussed. STATEMENT OF SIGNIFICANCE: Chronic wound infection and subsequent development of antibiotic resistance are serious clinical problems affecting millions of people worldwide. Antimicrobial peptides (AMPs) possess great potential in effectively killing the bacteria with minimal risk of resistance development. However, AMPs susceptibility to degradation following topical application limits their antimicrobial and wound healing effects. Therefore, development of an optimized topical formulation with high peptide stability and sustained AMP delivery is necessary to maximize the antimicrobial and wound healing effects. The present review provides an overview of the state-of-art in the field of topical AMP formulations for wound healing. Current developments in the field of topical AMP formulations are reviewed and future prospects for the development of effective combination AMP formulations are discussed.

The significance of collagen dressings in wound management: a review

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

Re-epithelialization of adult skin wounds: Cellular mechanisms and therapeutic strategies

Cutaneous wound healing in adult mammals is a complex multi-step process involving overlapping stages of blood clot formation, inflammation, re-epithelialization, granulation tissue formation, neovascularization, and remodelling. Re-epithelialization describes the resurfacing of a wound with new epithelium. The cellular and molecular processes involved in the initiation, maintenance, and completion of epithelialization are essential for successful wound closure. A variety of modulators are involved, including growth factors, cytokines, matrix metalloproteinases, cellular receptors, and extracellular matrix components. Here, we focus on cellular mechanisms underlying keratinocyte migration and proliferation during epidermal closure. Inability to re-epithelialize is a clear indicator of chronic non-healing wounds, which fail to proceed through the normal phases of wound healing in an orderly and timely manner. This review summarizes the current knowledge regarding the management and treatment of acute and chronic wounds, with a focus on re-epithelialization, offering some insights into novel future therapies.

ES2 as a Novel Verbascoside-Derived Compound in the Treatment of Cutaneous Wound Healing

Several pathologies are characterized by chronic wounds and often resistant to many of the common therapies, leading to chronic infections that can become even life-threatening for patients. For this reason, the identification of new products able to ameliorate the healing process is still an on-going research. Natural compounds have been used to improve skin conditions due to their dermo-cosmetic and therapeutic activities including anti-inflammatory, antioxidant and cell-migratory properties. Among these compounds, it has been recently demonstrated that Verbascoside, a phenyl propanoid glycoside widely used in the cosmetic field, can improve keratinocytes proliferation. Because of its high hydrophilic character, Verbascoside has a limited range of possible topical applications and the synthesis of ES2, a semi-synthetic derivative of Verbascoside was performed to bypass some of the drawback aspects of this molecule. In the present study, the wound healing properties of Verbascoside and ES2 were compared in both keratinocytes “in vitro” wound scratch and in wounded SKH1 mice. The results showed that both compounds were not cytotoxic and ES2 showed an efficient ability to promote the proliferation of human keratinocytes compared to Verbascoside. The findings were also confirmed in vivo but only at early time points (2/3 days). Taken together, these data suggest that the Verbascoside-derivative ES2 could be considered a novel and promising candidate for the topical treatment of wounds.

Galectin-3: One Molecule for an Alphabet of Diseases, from A to Z

Galectin-3 (Gal-3) regulates basic cellular functions such as cell-cell and cell-matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed.

Advanced Growth Factor Delivery Systems in Wound Management and Skin Regeneration

Growth factors are endogenous signaling molecules that regulate cellular responses required for wound healing processes such as migration, proliferation, and differentiation. However, exogenous application of growth factors has limited effectiveness in clinical settings due to their low in vivo stability, restricted absorption through skin around wound lesions, elimination by exudation prior to reaching the wound area, and other unwanted side effects. Sophisticated systems to control the spatio-temporal delivery of growth factors are required for the effective and safe use of growth factors as regenerative treatments in clinical practice, such as biomaterial-based drug delivery systems (DDSs). The current review describes the roles of growth factors in wound healing, their clinical applications for the treatment of chronic wounds, and advances in growth factor-loaded DDSs for enhanced wound healing, focusing on micro- and nano-particulate systems, scaffolds, hydrogels, and other miscellaneous systems.

Pretibial wounds: a review of current practice

Pretibial wounds are often associated with prolonged wound healing, particularly in the elderly female population. The wounds characteristically have either a proximally or distally based flap. Delayed wound healing has been attributed to flap necrosis and poor blood supply to this area. The aim of this review article is to examine the vascular anatomy, pathology and management options of patients with pretibial wounds.

The Effectiveness of Using a Lipido-Colloid Dressing for Patients With Traumatic Digital Wounds

This study compares the effect of a daily gauze dressing with that of a lipidocolloid dressing on the time taken to make up the dressing and efficacy of the management of traumatic digitalwounds. This is a randomized controlled trial of 28 patients (16 experimental and 12 control) with injuries to their fingers and loss of tissue. The patients in the experimental and control groups were given a lipido-colloid dressing and a daily gauze dressing, respectively. The patients'wounds were assessed in terms of the size of thewound and the time it took for thewound to heal. The findings showed that patients in the experimental group had a faster recovery time from the healing of their wound than the control group ( p= .024). The findings can help to establish an evidence-based practice in the management of traumatic digital wounds in clinical settings.

Examination of the role of galectins in cell migration and re-epithelialization of wounds

Re-epithelialization is a crucial step for wound healing. As galectins play important roles in re-epithelialization, we describe here protocols for in vivo, ex vivo and in vitro examination of the role of galectins in cell migration and in re-epithelialization of wounds. For in vivo models, mouse corneas are wounded by a variety of techniques and the rate of re-epithelialization is quantified. For ex vivo organ culture models, mouse corneas are wounded in situ, the eyes are enucleated, the eyeballs are cultured in the presence or absence of galectins and the rate of re-epithelialization is quantified. For cell cultured-based in vitro assays, we examine formation of lamellipodia and activation of focal adhesion kinase in various epithelial cells.

Role of galectins in re-epithelialization of wounds

Re-epithelialization is a critical contributing process in wound healing in the human body. When this process is compromised, impaired or delayed, serious disorders of wound healing may result that are painful, difficult to treat, and affect a variety of human tissues. Recent studies have demonstrated that members of the galectin class of β-galactoside-binding proteins modulate re-epithelialization of wounds by novel carbohydrate-based recognition systems. Galectins constitute a family of widely distributed carbohydrate-binding proteins with the affinity for the β-galactoside-containing glycans found on many cell surface and extracellular matrix (ECM) glycoproteins. There are 15 members of the mammalian galectin family that so far have been identified. Studies of the role of galectins in wound healing have revealed that galectin-3 promotes re-epithelialization of corneal, intestinal and skin wounds; galectin-7 promotes re-epithelialization of corneal, skin, kidney and uterine wounds; and galectins-2 and -4 promote re-epithelialization of intestinal wounds. Promising prospects for developing novel therapeutic strategies for the treatment of problematic, slow- or non-healing wounds are implicit in the findings that galectins stimulate the re-epithelialization of wounds of the cornea, skin, intestinal tract and kidney. Molecular mechanisms by which galectins modulate the process of wound healing are beginning to emerge and are described in this review.

The Electrical Response to Injury: Molecular Mechanisms and Wound Healing

Significance: Natural, endogenous electric fields (EFs) and currents arise spontaneously after wounding of many tissues, especially epithelia, and are necessary for normal healing. This wound electrical activity is a long-lasting and regulated response. Enhancing or inhibiting this electrical activity increases or decreases wound healing, respectively. Cells that are responsible for wound closure such as corneal epithelial cells or skin keratinocytes migrate directionally in EFs of physiological magnitude. However, the mechanisms of how the wound electrical response is initiated and regulated remain unclear. Recent Advances: Wound EFs and currents appear to arise by ion channel up-regulation and redistribution, which are perhaps triggered by an intracellular calcium wave or cell depolarization. We discuss the possibility of stimulation of wound healing via pharmacological enhancement of the wound electric signal by stimulation of ion pumping. Critical Issues: Chronic wounds are a major problem in the elderly and diabetic patient. Any strategy to stimulate wound healing in these patients is desirable. Applying electrical stimulation directly is problematic, but pharmacological enhancement of the wound signal may be a promising strategy. Future Directions: Understanding the molecular regulation of wound electric signals may reveal some fundamental mechanisms in wound healing. Manipulating fluxes of ions and electric currents at wounds might offer new approaches to achieve better wound healing and to heal chronic wounds.

Retention of polyurethane foam fragments during VAC therapy: a complication to be considered

Vacuum-assisted closure (VAC) therapy is a closed-loop, non-invasive active system, characterised by a controlled and localised negative pressure applied on porous polyurethane absorbent foams. It promotes healing of acute and chronic wounds. Therapeutic effects of VAC therapy have been proved and demonstrated; however, this method can have some disadvantages. Even if it is a quite versatile device, only qualified medical/paramedical personnel should use it in order to avoid possible complications that can occur after an improper application. In this report, 11 cases of foam-fragment retention within the wound are presented. This rare complication did not promote healing, but further hindered it. On the basis of our experience, it is mandatory to define the indications, benefits and limitations of VAC therapy.

Autologous keratinocyte suspension in platelet concentrate accelerates and enhances wound healing - a prospective randomized clinical trial on skin graft donor sites: platelet concentrate and keratinocytes on donor sites

Background

Wound healing involves complex mechanisms, which, if properly chaperoned, can enhance patient recovery. The abilities of platelets and keratinocytes may be harnessed in order to stimulate wound healing through the formation of platelet clots, the release of several growth factors and cytokines, and cell proliferation. The aim of the study was to test whether autologous keratinocyte suspensions in platelet concentrate would improve wound healing. The study was conducted at the Lausanne University Hospital, Switzerland in 45 patients, randomized to three different topical treatment groups: standard treatment serving as control, autologous platelet concentrate (PC) and keratinocytes suspended in autologous platelet concentrate (PC + K). Split thickness skin graft donor sites were chosen on the anterolateral thighs of patients undergoing plastic surgery for a variety of defects. Wound healing was assessed by the duration and quality of the healing process. Pain intensity was evaluated at day five.

Results

Healing time was reduced from 13.9 ± 0.5 days (mean ± SEM) in the control group to 7.2 ± 0.2 days in the PC group (P < 0.01). An addition of keratinocytes in suspension further reduced the healing time to 5.7 ± 0.2 days. Pain was reduced in both the PC and PC + K groups. Data showed a statistically detectable advantage of using PC + K over PC alone (P < 0.01).

Conclusion

The results demonstrate the positive contribution of autologous platelets combined with keratinocytes in stimulating wound healing and reducing pain. This strikingly simple approach could have a significant impact on patient care, especially critically burned victims for whom time is of the essence.

Clinical trial registry information

Protocol Record Identification Number: 132/03

Registry URL: http://www.clinicaltrials.gov

Molecular and culture-based assessment of the microbial diversity of diabetic chronic foot wounds and contralateral skin sites

Wound debridement samples and contralateral (healthy) skin swabs acquired from 26 patients attending a specialist foot clinic were analyzed by differential isolation and eubacterium-specific PCR-denaturing gradient gel electrophoresis (DGGE) in conjunction with DNA sequencing. Thirteen of 26 wounds harbored pathogens according to culture analyses, with Staphylococcus aureus being the most common (13/13). Candida (1/13), pseudomonas (1/13), and streptococcus (7/13) were less prevalent. Contralateral skin was associated with comparatively low densities of bacteria, and overt pathogens were not detected. According to DGGE analyses, all wounds contained significantly greater eubacterial diversity than contralateral skin (P < 0.05), although no significant difference in total eubacterial diversity was detected between wounds from which known pathogens had been isolated and those that were putatively uninfected. DGGE amplicons with homology to Staphylococcus sp. (8/13) and S. aureus (2/13) were detected in putatively infected wound samples, while Staphylococcus sp. amplicons were detected in 11/13 noninfected wounds; S. aureus was not detected in these samples. While a majority of skin-derived DGGE consortial fingerprints could be differentiated from wound profiles through principal component analysis (PCA), a large minority could not. Furthermore, wounds from which pathogens had been isolated could not be distinguished from putatively uninfected wounds on this basis. In conclusion, while chronic wounds generally harbored greater eubacterial diversity than healthy skin, the isolation of known pathogens was not associated with qualitatively distinct consortial profiles or otherwise altered diversity. The data generated support the utility of both culture and DGGE for the microbial characterization of chronic wounds.

Basics in nutrition and wound healing

Wound healing is a process that can be divided into three different phases (inflammatory, proliferative, and maturation). Each is characterized by certain events that require specific components. However, wound healing is not always a linear process; it can progress forward and backward through the phases depending on various intrinsic and extrinsic factors. If the wound-healing process is affected negatively, this can result in chronic wounds. Chronic wounds demand many resources in the clinical daily routine. Therefore, local wound management and good documentation of the wound is essential for non-delayed wound healing and prevention of the development of chronic wounds. During the wound-healing process much energy is needed. The energy for the building of new cells is usually released from body energy stores and protein reserves. This can be very challenging for undernourished and malnourished patients. Malnutrition is very common in geriatric patients and patients in catabolic phases of stress such as after injury or surgery. For that reason a close survey of the nutritional status of patients is necessary to start supplementation quickly, if applicable. Wound healing is indeed a very complex process that deserves special notice. There are some approaches to develop guidelines but thus far no golden standard has evolved. Because wounds, especially chronic wounds, cause also an increasing economic burden, the development of guidelines should be advanced.

Electrical fields in wound healing-An overriding signal that directs cell migration

Injury that disrupts an epithelial layer instantaneously generates endogenous electric fields (EFs), which were detected at human skin wounds over 150 years ago. Recent researches combining molecular, genetic and imaging techniques have provided significant insights into cellular and molecular responses to this "unconventional" signal. One unexpected finding is that the EFs play an overriding guidance role in directing cell migration in epithelial wound healing. In experimental models where other directional cues (e.g., contact inhibition release, population pressure etc.) are present, electric fields of physiological strength override them and direct cell migration. The electrotaxis or galvanotaxis is mediated by polarized activation of multiple signaling pathways that include PI3 kinases/Pten, membrane growth factor receptors and integrins. Genetic manipulation of PI3 kinase/Pten (Phosphoinositide 3-kinases/phosphatase and tensin homolog) and integrin beta4 demonstrated the importance of those molecules. The electric fields are therefore a fundamental signal that directs cell migration in wound healing. One of the most challenging question is: How do cells sense the very weak electric signals? Clinically, it is highly desirable to develop practical and reliable technologies for wound healing management exploiting the electric signaling.

The value of debridement and Vacuum-Assisted Closure (V.A.C.) Therapy in diabetic foot ulcers

BACKGROUND

Treatment of diabetic foot ulcers includes a number of different regimes such as glycaemic control, re-vascularization, surgical, local wound treatment, offloading and other non-surgical treatments. Although considered the standard of care, the scientific evidence behind the various debridements used is scarce. This presentation will focus on debridement and V.A.C. Therapy, two treatments widely used in patients with diabetes and foot ulcers.

METHODS

A review of existing literature on these treatments in diabetic foot ulcers, with focus on description of the various types of debridements used, the principles behind negative pressure wound therapy (NPWT) using the V.A.C. Therapy system and level of evidence.

RESULTS

Five randomized controlled trials (RCT) of debridement were identified; three assessed the effectiveness of a hydrogel as a debridement method, one evaluated surgical debridement and one evaluated larval therapy. Pooling the three hydrogel RCTs suggested that hydrogels are significantly more effective than gauze or standard care in healing diabetic foot ulcers. Surgical debridement and larval therapy showed no significant benefit. Other debridement methods such as enzyme preparations or polysaccharide beads have not been evaluated in RCTs of people with diabetes. More than 300 articles have been published on negative pressure wound therapy, including several small RCTs and a larger multi-centre RCT of diabetic foot ulcers. Negative pressure wound therapy seems to be a safe and effective treatment for complex diabetic foot wounds, and could lead to a higher proportion of healed wounds, faster healing rates, and potentially fewer re-amputations than standard care.

CONCLUSIONS

Although debridement of the ulcer is considered a prerequisite for healing of diabetic foot ulcers, the grade of evidence is quite low. This may be due to a lack of studies rather than lack of effect. Negative pressure wound therapy seems to be safe and effective in the treatment of some diabetic foot ulcers, although there is still only one well-performed trial that evaluates the effect.

Survey of bacterial diversity in chronic wounds using pyrosequencing, DGGE, and full ribosome shotgun sequencing

BACKGROUND

Chronic wound pathogenic biofilms are host-pathogen environments that colonize and exist as a cohabitation of many bacterial species. These bacterial populations cooperate to promote their own survival and the chronic nature of the infection. Few studies have performed extensive surveys of the bacterial populations that occur within different types of chronic wound biofilms. The use of 3 separate16S-based molecular amplifications followed by pyrosequencing, shotgun Sanger sequencing, and denaturing gradient gel electrophoresis were utilized to survey the major populations of bacteria that occur in the pathogenic biofilms of three types of chronic wound types: diabetic foot ulcers (D), venous leg ulcers (V), and pressure ulcers (P).

RESULTS

There are specific major populations of bacteria that were evident in the biofilms of all chronic wound types, including Staphylococcus, Pseudomonas, Peptoniphilus, Enterobacter, Stenotrophomonas, Finegoldia, and Serratia spp. Each of the wound types reveals marked differences in bacterial populations, such as pressure ulcers in which 62% of the populations were identified as obligate anaerobes. There were also populations of bacteria that were identified but not recognized as wound pathogens, such as Abiotrophia para-adiacens and Rhodopseudomonas spp. Results of molecular analyses were also compared to those obtained using traditional culture-based diagnostics. Only in one wound type did culture methods correctly identify the primary bacterial population indicating the need for improved diagnostic methods.

CONCLUSION

If clinicians can gain a better understanding of the wound's microbiota, it will give them a greater understanding of the wound's ecology and will allow them to better manage healing of the wound improving the prognosis of patients. This research highlights the necessity to begin evaluating, studying, and treating chronic wound pathogenic biofilms as multi-species entities in order to improve the outcomes of patients. This survey will also foster the pioneering and development of new molecular diagnostic tools, which can be used to identify the community compositions of chronic wound pathogenic biofilms and other medical biofilm infections.

Physiological effects of ultrasound mist on fibroblasts

BACKGROUND

Chronic wounds present an increasing challenge in healthcare and consume a substantial portion of healthcare cost. Although new treatments have been developed, treatment success has not been improved greatly. Ultrasound has long been employed in medicine. Its unique ability to deliver energy makes it an ideal candidate as a wound care modality. We proposed that ultrasound would differentially affect intracellular signaling pathways and, with the ability to assess this effect using a noncontact form of ultrasound, were provided with a means to test this proposal.

METHODS

The cellular morphology, mitogenic activities, expression of keratinocyte growth factor (KGF) and transforming growth factor beta-1 (TGF-beta1), and activation of extracellular regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways of dermal fibroblasts were studied after ultrasound treatment. Untreated and scrape-wounded fibroblasts were utilized as controls.

RESULTS

There was no difference in morphology observed, except for vacuolization in ultrasound-treated fibroblasts. Mitogenic activities were similar between ultrasound-treated and scrape-wounded fibroblasts. Ultrasound-treated fibroblasts exhibited a much earlier increase in KGF expression, ERK activation, and JNK activation. The ERK/JNK ratio was increased markedly in ultrasound-treated fibroblasts.

CONCLUSION

We conclude that ultrasound induces cellular responses that may be beneficial to wound healing.

Topical iodophor use in chronic wounds: a literature review

This study aimed to do a review of the literature regarding the use of topic iodine and/or compounds in the treatment of chronic wounds. The clinical trials were searched in the Cochrane database. Fourteen (58.3%) among 24 studies fulfilled the inclusion criteria. The articles were analyzed regarding journal and study characteristics and classified into three groups: Iodine versus other topic agents (7/ 50%); Iodine versus different dressings (6/ 42.9%); Iodine versus without Iodine (1/ 7.1%). Favorable results for the use of Iodine or similar product occurred in 50% of the analyzed studies. Six out of 8 trials showed favorable results for healing and infection prevention/ treatment; 4 out of 5 were not favorable when the healing objective was investigated and 1 study for infection treatment showed no favorable result.

Gefäßchirurgische Interventionen und plastisch-rekonstruktive Chirurgie

Despite the high prevalence of arterial occlusive disease, only a few studies have investigated the benefit of interventions to recanalize extremity arteries prior to plastic operations to close chronic wounds. The purpose of this study was to investigate the correlation of simple clinical examinations and apparative diagnostics of arterial occlusive disease of the lower extremity in patients with chronic wounds and to evaluate the benefit of vascular procedures to optimize wound perfusion before surgical closure. A total of 150 individuals with chronic wounds were included in this retrospective study. All patients underwent palpation of their foot pulses, Doppler sonography, and measurement of occlusive pressure. Positive results were tested by angiography. All patients with peripheral extremity vessel occlusion underwent vascular interventions prior to plastic operations for definitive wound closure. In all 34 patients with missing foot pulses, the clinical diagnosis of arterial occlusion could be confirmed by angiography. Peripheral recanalization and improved wound perfusion could be achieved in all patients. Arterial insufficiency could be diagnosed rapidly and safely using simple clinical examination such as palpation of foot pulses or measurement of occlusive pressures combined with Doppler sonography. Thus this simple and straightforward algorithm helped to secure the success of surgical therapy by shortening the time until wound-healing and reducing the psychosocial burden on the patient and financial costs to the health care system.

Debridement and wound bed preparation

Debridement can play a vital role in wound bed preparation and the removal of barriers that impair wound healing. In accordance with the TIME principles, debridement can help remove nonviable tissue, control inflammation or infection, decrease excess moisture, and stimulate a nonadvancing wound edge. There are many types of debridement, each with a set of advantages and disadvantages that must be clearly understood by the healthcare team. Failure to use the correct debridement method for a given type of wound may lead to further delays in healing, increase patient suffering, and unnecessarily increase the cost of care. This review article discusses the various methods of debridement, describes currently available debriding agents, evaluates the clinical data regarding their efficacy and safety, and describes strategies for the management of problematic nonhealing wounds.

Optimizing wound care with a new lipido-colloid dressing (Urgotul® Duo)

This non-comparative, multicentre clinical trial includes 43 patients whose acute or chronic wounds were treated with a new lipido-colloid dressing, Urgotul Duo, for at most 4 weeks, or until healing first occurred. The efficacy, tolerance and acceptability results obtained from this 'ready-for-use' dressing were similar to those reported for the Urgotul dressing in numerous previous clinical trials, and for all the different types of acute and chronic wounds. This well-tolerated new dressing greatly facilitates care operations in terms of execution (reduced use of supplementary gauzes for the secondary dressing) and duration (shorter nursing time), while improving patient comfort. This dressing is indicated for the local treatment of moderate exudative acute and chronic wounds in the granulation and epidermization phases.

A Painless Method of Ultrasonically Assisted Debridement of Chronic Leg Ulcers: A Pilot Study

OBJECTIVES

Devitalized tissue in a recalcitrant leg ulcer is common and may impede healing. The aim of this study was to evaluate the use of a non-invasive low frequency ultrasound device to debride chronic leg ulcers as an adjunct to compression bandages therapy.

METHODS

19 patients with leg ulceration of at least 6 months were recruited. Low frequency ultrasound at 25kHz was delivered by a portable Sonaca--180 via a handheld probe, using normal saline as the irrigation/coupling medium. The ultrasound was applied for 10-20 seconds per probe head area onto the ulcer. Each leg underwent treatment at an interval of 2-3 weeks with compression bandages reapplied at the end of the treatment. Serial colour photographs were taken to evaluate the response at each visit.

RESULTS

Each patient received on average 5.7 treatments each ranged from 5-20 minutes depending on the ulcer size. Symptomatic relief (pain and odour reduction) was achieved in 6 patients. 7 patients achieved complete ulcer healing (mean ulcer size=4.72+/-SD 1.872cm(2)) but no response was observed in 8 patients. There were no major complications of the treatment which was relatively painless.

CONCLUSIONS

The application of low frequency ultrasound debridement may heal some recalcitrant ulcers when standard compression regimens have failed. It is cheap and does not require admission. The role of simple wound cleansing requires further investigation.

Diabetic foot disorders. A clinical practice guideline (2006 revision)

The prevalence of diabetes mellitus is growing at epidemic proportions in the United States and worldwide. Most alarming is the steady increase in type 2 diabetes, especially among young and obese people. An estimated 7% of the US population has diabetes, and because of the increased longevity of this population, diabetes-associated complications are expected to rise in prevalence. Foot ulcerations, infections, Charcot neuroarthropathy, and peripheral arterial disease frequently result in gangrene and lower limb amputation. Consequently, foot disorders are leading causes of hospitalization for persons with diabetes and account for billion-dollar expenditures annually in the US. Although not all foot complications can be prevented, dramatic reductions in frequency have been achieved by taking a multidisciplinary approach to patient management. Using this concept, the authors present a clinical practice guideline for diabetic foot disorders based on currently available evidence, committee consensus, and current clinical practice. The pathophysiology and treatment of diabetic foot ulcers, infections, and the diabetic Charcot foot are reviewed. While these guidelines cannot and should not dictate the care of all affected patients, they provide evidence-based guidance for general patterns of practice. If these concepts are embraced and incorporated into patient management protocols, a major reduction in diabetic limb amputations is certainly an attainable goal.

The debridement of hard to heal leg ulcers by means of a new device based on Fluidjet technology

Debridement plays an essential role in the wound-bed preparation of necrotic and sloughy ulcers, being a mandatory step to achieve a well-debrided bed, proceeding towards healing. This study reports our experience with Versajet [Versajet Hydrosurgery System (Smith & Nephew, Hull, UK)], a new device for the debridement of exudating ulcers, based on Fluidjet technology, which excises and aspirates the unwanted tissue by using the Venturi effect. In a 10-month time period, a total of 68 patients, out of a setting of 167 patients, hospitalised as affected by chronic, hard-to-heal leg ulcers, stuck in the inflammatory phase, were treated with Versajet. Based on ulcer characteristics and clinical conditions, the remaining 99 patients underwent traditional debridement with moist dressings (controls). In the majority of Versajet-treated cases (46), an adequately debrided wound bed was achieved with one operative procedure; two and three procedures were required in 17 and 5 patients, respectively. Almost all the procedures were performed in the ward at the patient's bedside. This procedure is quick (mean time per treatment is about 5 minutes); when compared with a traditional treatment with moist dressings, Versajet considerably shortens the in-hospital stay and promotes a quicker healing process. When used by an experienced surgeon, Versajet allows a selective debridement, as it makes it possible to remove only the tissue centred in the working end and spare the healthy tissue. Debriding with Versajet is highly effective in reducing the bacterial load of the ulcer bed. The pain caused by Versajet is well tolerated, especially when set for gentle debridement. If multiple treatments are required, the combined use with moist dressings is synergistic, as the dressings soften the necrotic tissue, thus facilitating the following Versajet debridement. The results indicate that Versajet offers more precision than standard mechanical debridement and, at high settings, offers an alternative to surgical debridement.

Diagnosis and treatment of diabetic foot infections

EXECUTIVE SUMMARY: 1. Foot infections in patients with diabetes cause substantial morbidity and frequent visits to health care professionals and may lead to amputation of a lower extremity. 2. Diabetic foot infections require attention to local (foot) and systemic (metabolic) issues and coordinated management, preferably by a multidisciplinary foot-care team (A-II). The team managing these infections should include, or have ready access to, an infectious diseases specialist or a medical microbiologist (B-II). 3. The major predisposing factor to these infections is foot ulceration, which is usually related to peripheral neuropathy. Peripheral vascular disease and various immunological disturbances play a secondary role. 4. Aerobic Gram-positive cocci (especially Staphylococcus aureus) are the predominant pathogens in diabetic foot infections. Patients who have chronic wounds or who have recently received antibiotic therapy may also be infected with Gram-negative rods, and those with foot ischemia or gangrene may have obligate anaerobic pathogens. 5. Wound infections must be diagnosed clinically on the basis of local (and occasionally systemic) signs and symptoms of inflammation. Laboratory (including microbiological) investigations are of limited use for diagnosing infection, except in cases of osteomyelitis (B-II). 6. Send appropriately obtained specimens for culture before starting empirical antibiotic therapy in all cases of infection, except perhaps those that are mild and previously untreated (B-III). Tissue specimens obtained by biopsy, ulcer curettage, or aspiration are preferable to wound swab specimens (A-I). 7. Imaging studies may help diagnose or better define deep, soft-tissue purulent collections and are usually needed to detect pathological findings in bone. Plain radiography may be adequate in many cases, but MRI (in preference to isotope scanning) is more sensitive and specific, especially for detection of soft-tissue lesions (A-I). 8. Infections should be categorized by their severity on the basis of readily assessable clinical and laboratory features (B-II). Most important among these are the specific tissues involved, the adequacy of arterial perfusion, and the presence of systemic toxicity or metabolic instability. Categorization helps determine the degree of risk to the patient and the limb and, thus, the urgency and venue of management. 9. Available evidence does not support treating clinically uninfected ulcers with antibiotic therapy (D-III). Antibiotic therapy is necessary for virtually all infected wounds, but it is often insufficient without appropriate wound care. 10. Select an empirical antibiotic regimen on the basis of the severity of the infection and the likely etiologic agent(s) (B-II). Therapy aimed solely at aerobic Gram-positive cocci may be sufficient for mild-to-moderate infections in patients who have not recently received antibiotic therapy (A-II). Broad-spectrum empirical therapy is not routinely required but is indicated for severe infections, pending culture results and antibiotic susceptibility data (B-III). Take into consideration any recent antibiotic therapy and local antibiotic susceptibility data, especially the prevalence of methicillin-resistant S. aureus (MRSA) or other resistant organisms. Definitive therapy should be based on both the culture results and susceptibility data and the clinical response to the empirical regimen (C-III). 11. There is only limited evidence with which to make informed choices among the various topical, oral, and parenteral antibiotic agents. Virtually all severe and some moderate infections require parenteral therapy, at least initially (C-III). Highly bioavailable oral antibiotics can be used in most mild and in many moderate infections, including some cases of osteomyelitis (A-II). Topical therapy may be used for some mild superficial infections (B-I). 12. Continue antibiotic therapy until there is evidence that the infection has resolved but not necessarily until a wound has healed. Suggestions for the duration of antibiotic therapy are as follows: for mild infections, 12 weeks usually suffices, but some require an additional 12 weeks; for moderate and severe infections, usually 24 weeks is sufficient, depending on the structures involved, the adequacy of debridement, the type of soft-tissue wound cover, and wound vascularity (A-II); and for osteomyelitis, generally at least 46 weeks is required, but a shorter duration is sufficient if the entire infected bone is removed, and probably a longer duration is needed if infected bone remains (B-II). 13. If an infection in a clinically stable patient fails to respond to 1 antibiotic courses, consider discontinuing all antimicrobials and, after a few days, obtaining optimal culture specimens (C-III). 14. Seek surgical consultation and, when needed, intervention for infections accompanied by a deep abscess, extensive bone or joint involvement, crepitus, substantial necrosis or gangrene, or necrotizing fasciitis (A-II). Evaluating the limb's arterial supply and revascularizing when indicated are particularly important. Surgeons with experience and interest in the field should be recruited by the foot-care team, if possible. 15. Providing optimal wound care, in addition to appropriate antibiotic treatment of the infection, is crucial for healing (A-I). This includes proper wound cleansing, debridement of any callus and necrotic tissue, and, especially, off-loading of pressure. There is insufficient evidence to recommend use of a specific wound dressing or any type of wound healing agents or products for infected foot wounds. 16. Patients with infected wounds require early and careful follow-up observation to ensure that the selected medical and surgical treatment regimens have been appropriate and effective (B-III). 17. Studies have not adequately defined the role of most adjunctive therapies for diabetic foot infections, but systematic reviews suggest that granulocyte colony-stimulating factors and systemic hyperbaric oxygen therapy may help prevent amputations (B-I). These treatments may be useful for severe infections or for those that have not adequately responded to therapy, despite correcting for all amenable local and systemic adverse factors. 18. Spread of infection to bone (osteitis or osteomyelitis) may be difficult to distinguish from noninfectious osteoarthropathy. Clinical examination and imaging tests may suffice, but bone biopsy is valuable for establishing the diagnosis of osteomyelitis, for defining the pathogenic organism(s), and for determining the antibiotic susceptibilities of such organisms (B-II). 19. Although this field has matured, further research is much needed. The committee especially recommends that adequately powered prospective studies be undertaken to elucidate and validate systems for classifying infection, diagnosing osteomyelitis, defining optimal antibiotic regimens in various situations, and clarifying the role of surgery in treating osteomyelitis (A-III).