Physiology of the Chronic Wound

Skin and Wound Healing: Conventional Dosage versus Nanobased Emulsions Forms

The skin plays a crucial role in the body's homeostasis through its thermoregulation functions, metabolic activity, and, mainly, its barrier function. Once this system has its homeostasis disturbed, through the promotion of tissue discontinuity, an injury happens and a restoration process starts. Different products can be used to promote, accelerate, or stimulate the healing process, such as hydrogels, emulsions, and ointments (main conventional formulations). Despite the historical use and wide market and consumer acceptance, new systems emerged for wound management with the main challenge to overcome conventional form limitations, in which nanosystems are found, mainly nanobased emulsion forms (nano- and microemulsions, NE and ME). Here, we discuss the skin function and wound healing process, highlighting the cellular and molecular processes, the different wound classifications, and factors that affect physiological healing. We also investigated the recent patents (2012-2023) filed at the United States Patent and Trademark Office, where we found few patents for conventional forms (hydrogels = 5; emulsions = 4; ointments = 6) but a larger number of patents for nanobased emulsions filed in this time (NE = 638; ME = 4,072). Furthermore, we address the use of nanobased emulsions (NE and ME) and their particularities, differences, and application in wound treatment. This work also discusses the challenges, bottlenecks, and regulatory framework for nanosystems, industrial, academic, and government interest in nanotechnology, and future perspectives about this key factor for the nanosystems market and consumer acceptance.

Skin graft monitoring using forward-looking infrared thermal imaging

This study examined the feasibility of non-invasive infrared thermography to monitor skin graft viability. Sixty-three patients with skin defects attending a single institution from May 2022 to August 2023 were included. Patients underwent full-thickness or split-thickness skin grafts based on clinical indication. Infrared thermal images were obtained on postoperative days 0, 2, 4, 6 and 8. The temperature difference between the skin graft and surrounding normal skin was assessed using image analysis software. All 33 patients with full-thickness skin grafts showed successful healing. Among the 30 patients with split-thickness skin grafts, 7 experienced failure. The groups with successful full-thickness and split-thickness skin grafts exhibited a gradual increase in graft temperature, peaking on postoperative day 6 and decreasing on postoperative day 8. Temporal temperature changes were significant in each patient group (p < 0.001), and the differences in temperature change patterns between the two groups with successful grafts and the group with graft failure were also significant (p < 0.001). On postoperative day 6, the temperature difference was highest in the full-thickness skin graft group (0.197 ± 0.335°C), followed by the successful split-thickness skin graft group (0.426 ± 0.428°C), and the split-thickness skin graft group with graft failure (-2.100 ± 0.361°C). In conclusion, infrared thermal imaging can provide a non-invasive real-time assessment of graft status and predict graft success or failure.

Evaluation of risk factors associated with hard-to-heal wound infection in a tertiary care hospital

OBJECTIVE

The incidence of hard-to-heal wound infection, especially as a result of multidrug-resistant Gram-negative organisms, has increased in recent years. The reason for the increase is multifactorial and the ability of these pathogenic isolates to form biofilms is one of the important risk factors in wound infection. This study aimed to evaluate the risk factors associated with such cases.

METHOD

This prospective analytical study, conducted over a period of two months, included pus or tissue samples from hospital inpatients with Gram-negative hard-to-heal wound infection. The samples were processed with conventional microbiological techniques. Patient demographic details and the presence of various risk factors were recorded. Biofilm production was detected by tissue culture plate method in the laboratory. The data were analysed using SPSS version 21 (IBM Ltd., US).

RESULTS

The experimental cohort comprised 200 patients. Klebsiella spp. was the most common identified organism, followed by Escherichia coli and Pseudomonas spp. Carbapenem resistance was observed in 106 (53%) strains. Almost 66% of the strains showed biofilm formation. On evaluation of associated risk factors, age (p=0.043), presence of biofilms (p=0.0001), diabetes (p=0.002), hypertension (p=0.02) and medical device use (p=0.008) had significant association, whereas sex, previous surgery and prior antibiotic use had no significant impact on the chronicity of the wound.

CONCLUSION

In this study, chronicity of wounds was observed to be associated with multiple risk factors, especially the biofilm-forming ability of the strain. Biofilms are difficult to eradicate and additional measures, such as physical debridement, are important for resolving chronicity. Knowledge about specific risk factors would also allow clinicians a better understanding of the healing process and drive appropriate wound care interventions.

DECLARATION OF INTEREST

A grant was received from the Indian Council of Medical Research (ICMR) for this work (grant ID: 2017-02686). The authors have no conflicts of interest to declare.

Effects of an Ultra-Polished Scalpel on Incisional Wounds in a Diabetic Model

Inflammation after surgical incisions is related to the degree of tissue damage. Healing with low inflammation is desirable, especially in patients with compromised healing potential. This experimental study was conducted to assess the degree of inflammatory reaction and scar formation from incisions made by an ultra-polished scalpel (UPS). Two paravertebral incisions were made with a conventional scalpel (CS) and a UPS in 18 individual rats with diabetes. The fibrotic tissue (scar) area and expression levels of collagen, transforming growth factor, and matrix metalloproteinases were quantified on postoperative days 3, 7, and 30. The scar widths and areas were significantly lower in the UPS group than in the CS group. The scar widths were 64.3 ± 14.7 µm and 86.8 ± 12.1 µm in the UPS and CS groups, respectively ( P = 0.03). The scar areas were 11,398 ± 1595 µm 2 in the UPS group and 17,433 ± 3487 µm 2 in the CS group ( P = 0.014). The UPS group had less inflammation on day 3, less transforming growth factor synthesis on days 3 and 7, lower levels of matrix metalloproteinases, and less collagen synthesis on day 7 than did the CS group. The UPS achieved less local inflammation by reducing the local tissue damage in diabetic rat models, enabling better healing, and resulting in less scar formation. The UPS warrants further clinical study as it may bring beneficial outcomes for patients with impaired healing capability and patients who seek to reduce scarring.

Paracrine signalling between keratinocytes and SVF cells results in a new secreted cytokine profile during wound closure

Stromal vascular fraction (SVF) cells, and the adipose-derived mesenchymal stem cells they contain, have shown enhanced wound healing in vitro and in vivo, yet their clinical application has been limited. In this regard, understanding the mechanisms that govern SVF-enhanced wound healing would improve their application in the clinic. Here, we show that the SVF cells and keratinocytes engage in a paracrine crosstalk during wound closure, which results in a new cytokine profile that is distinct from the cytokines regularly secreted by either cell type on their own. We identify 11 cytokines, 5 of which are not regularly secreted by the SVF cells, whose expressions are significantly increased during wound closure by the keratinocytes. This new cytokine profile could be used to accelerate wound closure and initiate re-epithelialization without the need to obtain the SVF cells from the patient.

Polylactic Acid-Based Biomaterials in Wound Healing: A Systematic Review

OBJECTIVE

To examine (1) the effectiveness of polylactic acid (PLA)-based biomaterials in wound healing, (2) their effects on wound infection prevention, and (3) their safety compared with existing biomaterials.

DATA SOURCES

Data sources included PubMed, MEDLINE, Cochrane Library, CINAHL (Cumulative Index to Nursing and Allied Health Literature), CNKI (China National Knowledge Infrastructure), WEIPU, and WANFANG databases.

STUDY SELECTION

Investigators included 14 studies discussing the effects of PLA-based biomaterials in cutaneous wound healing published from 2000 to 2021.

DATA EXTRACTION

Authors extracted the following information from the selected studies: general information, study type, type of wound, PLA-based biomaterials and techniques, study period, outcome measures, and results.

DATA SYNTHESIS

Polylactic acid-based biomaterials may promote wound healing through wound area repair, collagen deposition, angiogenesis, and cell activities, which are related to the good biocompatibility, biodegradability, and moisture management properties of PLA. A proper product structure may also help. Both the native PLA materials and PLA blends seem to be antibacterial, although more evidence is needed for the native PLA products. Because there was no severe adverse event or obvious cytotoxicity observed in the included studies, PLA-based biomaterials are likely safe.

CONCLUSIONS

Polylactic acid-based biomaterials may be good wound dressing materials, although more evidence is needed to support their broader application in wound care.

Lignin-Cobalt Nano-Enabled Poly(pseudo)rotaxane Supramolecular Hydrogel for Treating Chronic Wounds

Chronic wounds (CWs) are a growing issue for the health care system. Their treatment requires a synergic approach to reduce both inflammation and the bacterial burden. In this work, a promising system for treating CWs was developed, comprising cobalt-lignin nanoparticles (NPs) embedded in a supramolecular (SM) hydrogel. First, NPs were obtained through cobalt reduction with phenolated lignin, and their antibacterial properties were tested against both Gram-negative and Gram-positive strains. The anti-inflammatory capacity of the NPs was proven through their ability to inhibit myeloperoxidase (MPO) and matrix metalloproteases (MMPs), which are enzymes involved in the inflammatory process and wound chronicity. Then, the NPs were loaded in an SM hydrogel based on a blend of α-cyclodextrin and custom-made poly(ether urethane)s. The nano-enabled hydrogel showed injectability, self-healing properties, and linear release of the loaded cargo. Moreover, the SM hydrogel's characteristics were optimized to absorb proteins when in contact with liquid, suggesting its capacity to uptake harmful enzymes from the wound exudate. These results render the developed multifunctional SM material an interesting candidate for the management of CWs.

Chronic Wound Healing Models

In this paper, we review and analyze the commonly available wound healing models reported in the literature and discuss their advantages and issues, considering their relevance and translational potential to humans. Our analysis includes different in vitro and in silico as well as in vivo models and experimental techniques. We further explore the new technologies in the study of wound healing to provide an all encompassing review of the most efficient ways to proceed with wound healing experiments. We revealed that there is not one model of wound healing that is superior and can give translatable results to human research. Rather, there are many different models that have specific uses for studying certain processes or stages of wound healing. Our analysis suggests that when performing an experiment to assess stages of wound healing or different therapies to enhance healing, one must consider not only the species that will be used but also the type of model and how this can best replicate the physiology or pathophysiology in humans.

Electrospinning Nanofibers as a Dressing to Treat Diabetic Wounds

Globally, diabetic mellitus (DM) is a common metabolic disease that effectively inhibits insulin production, destroys pancreatic β cells, and consequently, promotes hyperglycemia. This disease causes complications, including slowed wound healing, risk of infection in wound areas, and development of chronic wounds all of which are significant sources of mortality. With an increasing number of people diagnosed with DM, the current method of wound healing does not meet the needs of patients with diabetes. The lack of antibacterial ability and the inability to sustainably deliver necessary factors to wound areas limit its use. To overcome this, a new method of creating wound dressings for diabetic patients was developed using an electrospinning methodology. The nanofiber membrane mimics the extracellular matrix with its unique structure and functionality, owing to which it can store and deliver active substances that greatly aid in diabetic wound healing. In this review, we discuss several polymers used to create nanofiber membranes and their effectiveness in the treatment of diabetic wounds.

[Low-dose topical recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) therapy for chronic venous leg ulcers, 10-year follow-up]

BACKGROUND

The treatment of leg ulcers is an enormous problem worldwide. Chronic venous ulceration affects 1% of the population and often has a protracted course. Recurrence rate is high, ranging up to 69% in the first year after healing.

OBJECTIVES

To determine whether topical application of low-dose topical recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) is safe in venous leg ulcer treatment, and whether it accelerates healing rates and reduces recurrence rates.

MATERIALS AND METHODS

Consecutive patients with chronic venous leg ulcers received topical treatment with low-dose rhu GM-CSF (10 µg/mL 0.9% sodium chloride solution; 1.0-2.3 µg rhu GM-CSF/cm²) in combination with treatment of venous insufficiency. All patients were previously treated with other topical wound remedies for several weeks (median 8 weeks) without success.

RESULTS

In 119 of 130 patients, the wounds healed completely (91.5%). No local or systemic adverse reactions were observed. The mean time to healing was 24 weeks (median 14 weeks). Median follow-up of the 119 patients with healed ulcers was 84 months. The recurrence rates were 5.2% after 1 year, 18.9% after 4 years and 32.0% after 10 years.

CONCLUSIONS

Topical low-dose rhu GM-CSF proved to be safe and highly effective. Healing rates were comparable to those reported in the ESCHAR study (Effects of Surgery and Compression on Healing And Recurrence in venous ulceration) and recurrence rates were the lowest reported in the literature. Topical therapy with rhu GM-CSF can be applied in an outpatient setting and does not require hospitalization.

Reactive Oxygen Species Suppressive Kraft Lignin-Gelatin Antioxidant Hydrogels for Chronic Wound Repair

Chronic wound is difficult to repair because the normal wound healing mechanism is inhibited by the continuous inflammatory response. The delayed inflammatory responses generate high level of reactive oxygen species (ROS) at the wound sites, which leads to a longer inflammatory phase and induces a vicious cycle that interferes with the normal wound healing process. Therefore, ROS scavenging is an important factor for chronic wound healing. In this study, antioxidant hydrogel is developed by cross-linking kraft lignin, an antioxidant agent, and gelatin (Klig-Gel). Klig-Gel hydrogel is fabricated via ring opening reaction with epichlorohydrin as a cross-linker. High ROS scavenging activities are confirmed by various antioxidant evaluations, and in vitro natural antioxidant expression tests show reduction of oxidative stress. Mechanical properties of Klig-Gel hydrogel are tailorable by introducing different amount of kraft lignin to the hydrogel system. Biocompatibility is confirmed regardless of the kraft lignin content. Klig-Gel hydrogel is a promising ROS scavenging material that can be applied in various chronic wound healing applications.

Phospholipid-grafted PLLA electrospun micro/nanofibers immobilized with small extracellular vesicles from rat adipose mesenchymal stem cells promote wound healing in diabetic rats

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) can deliver a variety of bioactive factors to create a favorable local microenvironment, thereby holding huge potential in chronic wound repair. However, free sEVs administrated intravenously or locally are usually cleared rapidly, resulting in an insufficient duration of the efficacy. Thus, strategies that enable optimized retention and release profiles of sEVs at wound sites are desirable. Herein, we fabricated novel functional phosphoethanolamine phospholipid-grafted poly-l-lactic acid micro/nanofibers (DSPE-PLLA) to carry and retain sEVs from rat adipose MSCs, enabling the slow local release of sEVs. Our results showed that sEVs@DSPE-PLLA promoted the proliferation, migration and gene expression (Col I, Col III, TGF-β, α-SMA, HIF-1α) of fibroblasts. It also promoted keratinocyte proliferation. In addition, sEVs@DSPE-PLLA helped polarize macrophages toward the M2 phenotype by increasing the expression of anti-inflammatory genes (Arginase 1, CD 206, IL-10) and inhibiting the expression of pro-inflammatory genes (IL-1β, TNF-α). Further in vivo study in diabetic rat models showed that sEVs@DSPE-PLLA improved the wound-healing process by alleviating the inflammatory responses, stimulating cell proliferation, collagen deposition and angiogenesis. These results highlight the potential of using DSPE-grafted scaffolds for extracellular vesicle immobilization and suggest sEVs@DSPE-PLLA micro/nanofibers as promising functional wound dressings for diabetic wounds.

Milk fat-globule epidermal growth factor 8: A potential Regulator of Cutaneous Wound Healing

Destroying the integrity of the skin may causes disability and even death from injury or illness. Wound healing is a core mechanism to maintain skin barrier function. Milk fat-globule epidermal growth factor 8 (MFG-E8) is a key factor in wound healing and is involved in regulating blood coagulation, mediating macrophage uptake of apoptotic cells, shifting macrophages from an inflammatory to an anti-inflammatory phenotype, promoting angiogenesis, enhancing vascular endothelial growth factor (VEGF) signaling, and assisting wound tissue perfusion. However, these abilities are dysregulated in pathological conditions, such as glucose disorders and ischemic injury. Restricted application of exogenous MFG-E8 can restore function and play a beneficial role in cutaneous wound healing.

Multifarious applications of bioactive glasses in soft tissue engineering

Tissue engineering (TE), a new paradigm in regenerative medicine, repairs and restores the diseased or damaged tissues and eliminates drawbacks associated with autografts and allografts. In this context, many biomaterials have been developed for regenerating tissues and are considered revolutionary in TE due to their flexibility, biocompatibility, and biodegradability. One such well-documented biomaterial is bioactive glasses (BGs), known for their osteoconductive and osteogenic potential and their abundant orthopedic and dental clinical applications. However, in the last few decades, the soft tissue regenerative potential of BGs has demonstrated great promise. Therefore, this review comprehensively covers the biological application of BGs in the repair and regeneration of tissues outside the skeleton system. BGs promote neovascularization, which is crucial to encourage host tissue integration with the implanted construct, making them suitable biomaterial scaffolds for TE. Moreover, they heal acute and chronic wounds and also have been reported to restore the injured superficial intestinal mucosa, aiding in gastroduodenal regeneration. In addition, BGs promote regeneration of the tissues with minimal renewal capacity like the heart and lungs. Besides, the peripheral nerve and musculoskeletal reparative properties of BGs are also reported. These results show promising soft tissue regenerative potential of BGs under preclinical settings without posing significant adverse effects. Albeit, there is limited bench-to-bedside clinical translation of elucidative research on BGs as they require rigorous pharmacological evaluations using standardized animal models for assessing biomolecular downstream pathways.

Differential Capability of Clinically Employed Dermal Regeneration Scaffolds to Support Vascularization for Tissue Bioengineering

The loss of skin integrity has always represented a major challenge for clinicians dealing with dermal defects, such as ulcers (diabetic, vascular and chronic), postoncologic resections (i.e., radical vulvectomy) or dermatologic disorders. The introduction in recent decades of acellular dermal matrices (ADMs) supporting the repair and restoration of skin functionality represented a significant step toward achieving clean wound repair before performing skin grafts. Hard-to-heal ulcers generally depend on local ischemia and nonadequate vascularization. In this context, one possible innovative approach could be the prevascularization of matrices with vessel-forming cells (inosculation). This paper presents a comparative analysis of the most widely used dermal templates, i.e., Integra^® Bilayer Matrix Wound Dressing, PELNAC^®, PriMatrix^® Dermal Repair Scaffold, Endoform^® Natural Dermal Template, and Myriad Matrix^®, testing their ability to be colonized by human adult dermal microvascular endothelial cells (ADMECs) and to induce and support angiogenesis in vitro and in vivo. By in vitro studies, we demonstrated that Integra^® and PELNAC^® possess superior pro-adhesive and pro-angiogenetic properties. Animal models allowed us to demonstrate the ability of preseeded ADMECs on Integra^® to promote the engraftment, integration and vascularization of ADMs at the site of application.

Development and evaluation of drug delivery patch for topical wound healing application

Wound treatment remains a challenge to many clinicians because of the complexities of the wound healing process. With the astonishing progress of biomedical engineering during the past few decades, conventional drug delivery systems have been evolved into smart drug delivery systems with stimuli-responsive characteristics. The objective of this study was to develop and evaluate an electromechanically actuated drug dispensation device which can release active pharmaceutical compound in a controlled fashion. Additive manufacturing was employed to design and fabricate the device. Haptic technology was used to provide stimulation for drug release, and Cicatrin was used to evaluate the drug release patterns of device. Drug release study was comprised of in vitro drug release, static study, and the purpose of this study was to develop a compliance chart for different wound conditions. The effectiveness of shortlisted drug regimen from compliance chart was validated through microbial study and animal studies. The results of animal studies were compared with commercially available drug release systems. The results of drug release studies gave different dose regimens for different wound conditions. The effective dose regimen was able to create 1-cm-wide microbial zone of inhibitions. The wound healing rate of mice for commercially available release system for five consecutive days was 10%, 10%, 20%, 40% and 50% and for test device was 10%, 30%, 60%, 90% and 100%. Hence, the device proved its effectiveness and efficacy of dosage regimen for wound healing applications through in vitro, microbial and in vivo studies. In conclusion, this device proved to be an accurate and specific drug delivery system with improved medication and therapeutic outcomes for personalized medication.

Medical gas plasma-stimulated wound healing: Evidence and mechanisms

Defective wound healing poses a significant burden on patients and healthcare systems. In recent years, a novel reactive oxygen and nitrogen species (ROS/RNS) based therapy has received considerable attention among dermatologists for targeting chronic wounds. The multifaceted ROS/RNS are generated using gas plasma technology, a partially ionized gas operated at body temperature. This review integrates preclinical and clinical evidence into a set of working hypotheses mainly based on redox processes aiding in elucidating the mechanisms of action and optimizing gas plasmas for therapeutic purposes. These hypotheses include increased wound tissue oxygenation and vascularization, amplified apoptosis of senescent cells, redox signaling, and augmented microbial inactivation. Instead of a dominant role of a single effector, it is proposed that all mechanisms act in concert in gas plasma-stimulated healing, rationalizing the use of this technology in therapy-resistant wounds. Finally, addressable current challenges and future concepts are outlined, which may further promote the clinical utilization, efficacy, and safety of gas plasma technology in wound care in the future.

Evaluation of pro-angiogenic properties of an inorganic silica gel fibre fleece

Hard-to-heal wounds represent an increasing health and economic burden on society. At present, therapy options for hard-to-heal wounds are often unsatisfactory, and the development of more effective wound treatments is urgently needed. We have shown that orthosilicic acid-releasing silica fibre fleece (SIFIB), via its pronounced anti-inflammatory properties, exhibited a significantly enhanced effect on wound closure kinetics in a porcine wound model in vivo. In this present study, we have examined in vitro the impact of the pro-angiogenic potential of SIFIB. Using an in vitro angiogenesis assay we describe for the first time how an inorganic biodegradable silica-based material significantly improved endothelial microvessel-like structure formation. We further demonstrate that the molecular mechanism of this pro-angiogenic activity of SIFIB is based on a significantly increased and tumour necrosis factor (TNF)α-dependent VEGF protein expression. In conclusion, due to its positive effects on angiogenesis, our results further indicate that decomposition products of silica-based biodegradable inorganic materials might represent very relevant therapeutic components of modern wound dressings for the treatment of hard-to-heal wounds.

Evaluation of the combination of a biofilm-disrupting agent and negative pressure wound therapy: a case series

OBJECTIVE

Approximately three million people in the US have hard-to-heal pressure ulcers (PUs), including 10% of hospitalised patients. Healing depends on ulcer stage and patient comorbidities. Despite advances in nutrition and wound care, PUs can take months or years to reach complete closure. To date, clinical studies have focused on single modality therapy. However, there is no one therapy that can address all of the deficits in these complex, hard-to-heal wounds. A commonly used treatment for PUs, negative pressure wound therapy (NPWT), has demonstrated improved healing in Stage 3 and 4 PUs. NPWT entails applying suction to a porous sponge fitted into the wound cavity and sealed with an occlusive dressing. Negative pressure facilitates wound healing by removing wound fluid containing harmful proteases, stimulating the formation of granulation tissue and promoting wound contracture. However, it does not affect biofilm formation. We hypothesised that adding an antibiofilm agent might increase the effectiveness of NPWT in recalcitrant PUs.

METHOD

A prospective case series was conducted in outpatient wound care centres and a skilled nursing facility to examine the combination of a biofilm-disrupting antimicrobial agent (Blast-X, Next Science, US) in combination with NPWT (VAC, 3M, US) in healing and reducing bacterial burden in treatment-resistant pressure ulcers. Patients consented to application of the antibiofilm agent and NPWT three times per week for four weeks. The wounds were measured, imaged for bacteria and tested for host and bacterial protease activity weekly.

RESULTS

Of the 10 patients, four dropped out of the study before the end of the four weeks. Of the remaining six, four patients experienced a reduction in wound surface area and volume, reduced protease activity and lower bacterial levels.

CONCLUSION

The results of this study showed that multimodal therapy, including NPWT and biofilm disruption, may restart the healing of stagnant treatment-resistant PUs.

Sacral and Ischial Pressure Ulcer Management With Negative-Pressure Wound Therapy With Instillation and Dwell

BACKGROUND

The addition of topical fluid instillation, a programmable "dwell" time and a novel foam-wound interface to the established wound healing benefits of negative-pressure wound therapy (NPWT) works synergistically to benefit patients with complex wounds. This engineering breakthrough for wound care has been termed NPWT with instillation and dwell (NPWTi-d), and the new foam dressings are reticulated open cell foam dressings specifically designed for use with NPWTi-d. This combined technology has shown promise in chronic, complex wounds and has potential for the management of sacral and ischial pressure wounds.

METHODS

A qualitative comprehensive review was performed analyzing articles from PubMed and Medline that reported on the use of NPWTi-d in sacral or ischial pressure ulcers. Case series and case reports were predominant, and results of cases specific to sacral and ischial pressure wounds were extracted from larger studies and summarized for presentation.

RESULTS

Compared with conventional NPWT alone, NPWTi-d has been shown to help irrigate the wound, remove fibrinous debris, and promote granulation tissue formation. This is associated with a decreased number of operative debridements and decreased hospital length of stay.

CONCLUSIONS

This technology is rapidly demonstrating expanded utilization in hospitalized patients with chronic sacral and ischial pressure ulcers. When used correctly, NPWTi-d serves as an effective "bridge to defined endpoint": whether that is a flap reconstruction, skin grafting, or discharge home with a stable chronic wound and simplified wound care.

Nanoceutical Adjuvants as Wound Healing Material: Precepts and Prospects

Dermal wound healing describes the progressive repair and recalcitrant mechanism of 12 damaged skin, and eventually, reformatting and reshaping the skin. Many probiotics, nutritional supplements, metal nanoparticles, composites, skin constructs, polymers, and so forth have been associated with the improved healing process of wounds. The exact mechanism of material-cellular interaction is a point of immense importance, particularly in pathological conditions such as diabetes. Bioengineered alternative agents will likely continue to dominate the outpatient and perioperative management of chronic, recalcitrant wounds as new products continue to cut costs and improve the wound healing process. This review article provides an update on the various remedies with confirmed wound healing activities of metal-based nanoceutical adjuvanted agents and also other nano-based counterparts from previous experiments conducted by various researchers.

Comparative Antimicrobial Activity of Commercial Wound Care Solutions on Bacterial and Fungal Biofilms

BACKGROUND

Biofilms represent a complex milieu of matrix-enclosed microorganisms, which can significantly contribute to the pathology of chronic wounds. In this study, we compare the activity of 3 commercial antimicrobial wound care solutions, Vashe (HOCl based), PhaseOne (HOCl based), and Sulfamylon (mafenide acetate), for their in vitro activity against bacterial and fungal biofilms.

METHODS

Reference and clinical isolates of 6 Gram-negative bacterial species (36 total strains), 3 Gram-positive bacteria (21 strains), and 3 Candida species (9 strains) were used to create biofilms. Various working concentrations of the 3 antiseptic agents were incubated with the biofilms in microwell plates; they were monitored from 1 minute to 24 hours to compare bacterial and fungal viability through colony forming unit analysis.

RESULTS

Vashe and PhaseOne displayed excellent bactericidal and fungicidal activity, whereas Sulfamylon demonstrated minimal activity against the biofilms tested. With the exception of Candida albicans, all biofilms were eliminated at either 1 or 10 minutes using Vashe and PhaseOne solutions. In most cases, mafenide was unable to eliminate both bacterial and fungal biofilms, even with 24 hours of treatment.

CONCLUSIONS

Biofilms represent a major clinical challenge, with no clear consensus for treatment of chronic wounds or prosthetic devices. Our results suggest that hypochlorous acid-based wound solutions such as Vashe and PhaseOne are more efficacious than mafenide in eliminating bacterial and fungal biofilms. Further studies are necessary to investigate and compare the in vivo efficacy of these products in clinical care.

Retinal capillary basement membrane thickening: Role in the pathogenesis of diabetic retinopathy

Vascular basement membrane (BM) thickening has been hailed over half a century as the most prominent histological lesion in diabetic microangiopathy, and represents an early ultrastructural change in diabetic retinopathy (DR). Although vascular complications of DR have been clinically well established, specific cellular and molecular mechanisms underlying dysfunction of small vessels are not well understood. In DR, small vessels develop insidiously as BM thickening occurs. Studies examining high resolution imaging data have established BM thickening as one of the foremost structural abnormalities of retinal capillaries. This fundamental structural change develops, at least in part, from excess accumulation of BM components. Although BM thickening is closely associated with the development of DR, its contributory role in the pathogenesis of DR is coming to light recently. DR develops over several years before clinical manifestations appear, and it is during this clinically silent period that hyperglycemia induces excess synthesis of BM components, contributes to vascular BM thickening, and promotes structural and functional lesions including cell death and vascular leakage in the diabetic retina. Studies using animal models show promising results in preventing BM thickening with subsequent beneficial effects. Several gene regulatory approaches are being developed to prevent excess synthesis of vascular BM components in an effort to reduce BM thickening. This review highlights current understanding of capillary BM thickening development, role of BM thickening in retinal vascular lesions, and strategies for preventing vascular BM thickening as a potential therapeutic strategy in alleviating characteristic lesions associated with DR.

Bacteria and Antibiotics in Wound Healing

This review of the literature concerning bacteria, antibiotics and tissue repair shows there are extensive data supporting microbial interference with wound healing once bacterial burden exceeds 104 CFU per unit of measure, The mechanism of bacterial interference lies largely in prolonging the inflammatory phase of tissue repair. Reducing the microbial bioburden allows tissue repair to continue. Systemic and topical antimicrobials appear critical to reducing the bioburden and facilitating repair. The current controversy over the use of antimicrobials in patients with chronically infected wounds, in particular, revolves around the definition of infection. The reliance on classic clinical signs of inflammation to support antimicrobial use in these patients is tenuous due to the lack of correlation of these signs with the microbial burden known to impair tissue repair.

In vitro bactericidal activity of a carbohydrate polymer with zinc oxide for the treatment of chronic wounds

Introduction. Biological adhesives and effective topical therapeutic agents that improve wound healing are urgently required for the treatment of chronic ulcers. A biodegradable adhesive based on a carbohydrate polymer with zinc oxide (CPZO) was shown to possess anti-inflammatory activity and enhance wound healing, but its bactericidal activity was unknown.Aim. To investigate the bactericidal activity of CPZO against bacteria commonly present as infectious agents in chronic wounds.Methodology. We examined the bactericidal activity of CPZO against three biofilm-producing bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) through three strategies: bacterial suspension, biofilm disruption and in vitro wound biofilm model.Results. In suspension cultures, CPZO had direct, potent bactericidal action against S. aureus within 24 h, whereas E. coli took 7 days to be eliminated. By contrast, P. aeruginosa survived up to 14 days with CPZO. CPZO had biofilm disruption activity against clinical isolates of S. aureus in the anti-biofilm test. Finally, in the in vitro wound biofilm model, CPZO dramatically reduced the bacterial viability of S. aureus and P. aeruginosa.Conclusions. Together with its previously shown anti-inflammatory properties, the bactericidal activity of CPZO gives it the potential to be a first-line therapeutic option for chronic various ulcers and, possibly, other chronic ulcers, preventing or controlling microbial infections, and leading to the healing of such complicated chronic ulcers.

Subeschar culture using a punch instrument in unstageable wounds

Background

A patient’s overall condition sometimes does not allow for the complete removal of a dead eschar or injured slough in cases involving a pressure-injury skin lesion. This frequently occurs in clinical practice, particularly in bedridden and older patients receiving home care or intensive care. Even after debridement, it is also difficult to manage open exudative wounds in these patients. Nevertheless, when a mature or immature eschar is treated without proper debridement, liquefaction necrosis underneath the eschar or slough tends to reveal a large, open wound with infectious exudates. We hypothesized that if the presence of any bacteria under the eschar can be evaluated and the progression of the presumed infection of the subeschar can be halted or delayed without creating an open wound, the final wound can be small, shallow, and uninfected.

Methods

Using a punch instrument, we performed 34 viable subeschar tissue cultures with a secure junction between the eschar and the normal skin.

Results

The bacterial study had 29 positive results. Based on these results and the patient’s status, appropriate antibiotics could be selected and administered. The use of suitable antibiotics led to relatively shallow and small exposed wounds.

Conclusions

This procedure could be used to detect potentially pathogenic bacteria hidden under black or yellow eschars. Since subeschar infections are often accompanied by multidrug-resistant bacteria, the early detection of hidden infections and the use of appropriate antibiotics are expected to be helpful to patients.

Malignant Transformation in Diabetic Foot Ulcers-Case Reports and Review of the Literature

An imbalance of regeneration and destruction of the extracellular matrix due to a plethora of chemo- and cytokines, elevated matrix metalloproteinases, bacterial contamination and repetitive painless tissue damage can lead the chronicity of a wound, especially in diabetic foot ulcers (DFU). Along general lines, wound healing and cancer development are similar. Therefore chronic wounds prepare a breeding ground for cancer development. Several characteristics such as increase in size, verrucous everted margins and contact bleeding are suspicious for malignant growth in a chronic wound. While previously the term Marjolin's ulcer was attributed to a malignant tumor in (burn) scars, it is nowadays used for every malignant tumor in chronic wounds. Furthermore, chronic ulcers in diabetic feet are susceptible for malignant transformation. We describe two cases of squamous cell carcinoma in patients with DFU-a 71 year-old woman and a 67 year old man. Both received total tumor excision and split-skin grafts with good short-time results.

Cell salvage in acute and chronic wounds: a potential treatment strategy. Experimental data and early clinical results

On 9 May 2018, the authors took part in a closed panel discussion on the impact of cell salvage in acute and chronic wounds. The goal was to deliberate the possible use of plurogel micelle matrix (PMM) as a new treatment strategy for wound healing and the authors openly shared their experiences, thoughts, experimental data and early clinical results. The outcome of the panel discussion has been abridged in this paper. The cell membrane consists of a lipid bilayer, which provides a diffusion barrier separating the inside of a cell from its environment. Cell membrane injury can result in acute cellular necrosis when defects are too large and cannot be resealed. There is a potential hazard to the body when these dying cells release endogenous alarm signals referred to as 'damage (or danger) associated molecular patterns' (DAMPs), which trigger the innate immune system and modulate inflammation. Cell salvage by membrane resealing is a promising target to ensure the survival of the individual cell and prevention of further tissue degeneration by inflammatory processes. Non-ionic surfactants such as poloxamers, poloxamines and PMM have the potential to resuscitate cells by inserting themselves into damaged membranes and stabilising the unstable portions of the lipid bilayers. The amphiphilic properties of these molecules are amenable to insertion into cell wall defects and so can play a crucial, reparative role. This new approach to cell rescue or salvage has gained increasing interest as several clinical conditions have been linked to cell membrane injury via oxidative stress-mediated lipid peroxidation or thermal disruption. The repair of the cell membrane is an important step in salvaging cells from necrosis to prevent further tissue degeneration by inflammatory processes. This is applicable to acute burns and chronic wounds such as diabetic foot ulcers (DFUs), chronic venous leg ulcers (VLUs), and pressure ulcers (PUs). Experimental data shows that PMM is biocompatible and able to insert itself into damaged membranes, salvaging their barrier function and aiding cell survival. Moreover, the six case studies presented in this paper reveal the potential of this treatment strategy.

Nanofiber-expanded human CD34+ cells heal cutaneous wounds in streptozotocin-induced diabetic mice

Despite advances in diabetic wound care, the significant number of amputations that occur every year demands more effective therapeutics. Herein, we offer an aminated polyethersulfone nanofiber-expanded human umbilical cord blood-derived CD34⁺ cells (henceforth CD34⁺ cells) effective therapy, tested in cutaneous wounds developed in streptozotocin-induced diabetic NOD/SCID mice. We show that systemic administration of CD34⁺ cells homed to the wound site and significantly accelerated wound closure. Wound closure was associated with improved re-epithelialization and increased neovascularization; and with decreased sustained pro-inflammatory activity of NF-κB and its downstream effector molecules TNF-α, IL-1β, and IL-6 at the wound bed. This finding was further supported by the observation of a decreased number of myeloperoxidase positive neutrophils, and concomitantly increased levels of IL-10. In addition, improved granulation tissue formation was observed along with higher collagen deposition and myofibroblasts and decreased expressions of MMP-1. Mechanistically, CD34⁺ cells reduced the level of MMP-1 expression by inhibiting recruitment of NF-κB to the MMP-1 promoter site in dermal fibroblasts. In summary, we provide evidence of a novel nanofiber-expanded CD34⁺ stem cell therapeutic development for treating diabetic wounds by defining their cellular and molecular mechanisms.

Effect of negative pressure wound therapy on molecular markers in diabetic foot ulcers

Diabetic foot ulcers are one of the most common complications of diabetes with high morbidity and mortality. Negative pressure wound therapy (NPWT) is one of the treatment modalities that facilitates the wound healing process; however, its molecular mechanism remains unclear. The aim of this study was to investigate the mechanism of action of NPWT in the treatment of diabetic foot ulcers via measuring the tissue expression of genes related to the wound healing process. The study included 40 patients with diabetic foot ulceration, 20 of them received NPWT and the other 20 were a control group treated with advanced moist therapy. Granulation tissue biopsies were obtained before and 10 days after treatment in both groups and subjected to real-time polymerase chain reaction to measure the mRNA expression of TGF-β1, VEGF, TNF-α, IL-1β, MMP-1, MMP-9 and TIMP-1 which are involved in the wound healing pathway. After 10 days of treatment with NPWT, the mRNA levels of IL-1β, TNF-α, MMP-1, and MMP-9 were significantly downregulated, while the levels of VEGF, TGF-β1 and TIMP-1 were significantly increased. Our study demonstrated that NPWT promotes wound healing in diabetic foot ulcers possibly by affecting growth factors, inflammatory cytokines, and matrix metalloproteinases.

Functional characterisation of bioactive peptide derived from terrestrial snail Cryptozona bistrialis and its wound-healing property in normal and diabetic-induced Wistar albino rats

A peptide might be an exciting biomaterial or template for the development of novel wound-healing agents. In this report, it was isolated from the terrestrial snail Cryptozona bistrialis by enzymatic digestion and was evaluated for its in vitro wound-healing activity in NIH/3T3 mouse fibroblasts cell line and in vivo wound-healing activity in normal and diabetic-induced Wistar albino rats. The C. bistrialis protein was digested by the papain enzyme, and 21.79 kDa peptide (Cb-peptide) was purified by reversed-phase high-performance liquid chromatography and identified by MALDI (matrix-assisted laser desorption/ionization)-TOF analysis. The isolated Cb-peptide was characterised by various analytical methods. The peptide demonstrated a capacity to prevent the development of pathogenic bacterial and fungal cultures and proved that it promotes significant wound-healing activity in the wound scratch assay method by rapid cell migration and closure of wound. Isolated Cb-peptide was lyophilised and formulated to ointment and analysed for in vivo wound-healing activity in normal and diabetic (alloxan monohydrate)-induced Wistar albino rats. Cb-peptide ointment-treated groups showed a greater degree of wound healing and early and complete period of epithelialisation in normal and diabetic-induced Wistar albino rats. Cb-peptide ointment-treated groups showed significant excision and incision wound-healing activity. A conclusion was reached that the peptide isolated from C. bistrialis showed greater wound-healing activity compared with vehicle control and standard control.

Pro-Inflammatory Chemokines and Cytokines Dominate the Blister Fluid Molecular Signature in Patients with Epidermolysis Bullosa and Affect Leukocyte and Stem Cell Migration

Hereditary epidermolysis bullosa (EB) is associated with skin blistering and the development of chronic nonhealing wounds. Although clinical studies have shown that cell-based therapies improve wound healing, the recruitment of therapeutic cells to blistering skin and to more advanced skin lesions remains a challenge. Here, we analyzed cytokines and chemokines in blister fluids of patients affected by dystrophic, junctional, and simplex EB. Our analysis revealed high levels of CXCR1, CXCR2, CCR2, and CCR4 ligands, particularly dominant in dystrophic and junctional EB. In vitro migration assays demonstrated the preferential recruitment of CCR4⁺ lymphocytes and CXCR1⁺, CXCR2⁺, and CCR2⁺ myeloid cells toward EB-derived blister fluids. Immunophenotyping of skin-infiltrating leukocytes confirmed substantial infiltration of EB-affected skin with resting (CD45RA⁺) and activated (CD45RO⁺) T cells and CXCR2⁺ CD11b⁺ cells, many of which were identified as CD16b⁺ neutrophils. Our studies also showed that abundance of CXCR2 ligand in blister fluids also creates a favorable milieu for the recruitment of the CXCR2⁺ stem cells, as validated by in vitro and in-matrix migration assays. Collectively, this study identified several chemotactic pathways that control the recruitment of leukocytes to the EB-associated skin lesions. These chemotactic axes could be explored for the refinement of the cutaneous homing of the therapeutic stem cells.

In vitro assessment of a novel, hypothermically stored amniotic membrane for use in a chronic wound environment

Chronic wounds require extensive healing time and place patients at risk of infection and amputation. Recently, a fresh hypothermically stored amniotic membrane (HSAM) was developed and has subsequently shown promise in its ability to effectively heal chronic wounds. The purpose of this study is to investigate the mechanisms of action that contribute to wound-healing responses observed with HSAM. A proteomic analysis was conducted on HSAM, measuring 25 growth factors specific to wound healing within the grafts. The rate of release of these cytokines from HSAMs was also measured. To model the effect of these cytokines and their role in wound healing, proliferation and migration assays with human fibroblasts and keratinocytes were conducted, along with tube formation assays measuring angiogenesis using media conditioned from HSAM. Additionally, the cell-matrix interactions between fibroblasts and HSAM were investigated. Conditioned media from HSAM significantly increased both fibroblast and keratinocyte proliferation and migration and induced more robust tube formation in angiogenesis assays. Fibroblasts cultured on HSAMs were found to migrate into and deposit matrix molecules within the HSAM graft. These collective results suggest that HSAM positively affects various critical pathways in chronic wound healing, lending further support to promising qualitative results seen clinically and providing further validation for ongoing clinical trials.

Mesenchymal stem cells-derived MFG-E8 accelerates diabetic cutaneous wound healing

BACKGROUND

Diabetic wounds are intractable due to complex factors, such as the inhibition of angiogenesis, dysfunction of phagocytosis by macrophages and abnormal inflammatory responses. It is recognized that mesenchymal stem cells (MSCs) promote wound healing in diabetic mice. We previously demonstrated that MSCs produce large amounts of MFG-E8.

OBJECT

The objective was to ascertain the role of MSCs-derived MFG-E8 in murine diabetic wounds.

METHODS

MFG-E8 WT/KO MSCs or rMFG-E8 were subcutaneously injected around the wound in diabetic db/db mice, and wound areas were analyzed. Quantification of angiogenesis, infiltrating inflammatory cells, apoptotic cells at the wound area was performed by immunofluorescence staining and real-time PCR. Phagocytosis assay was performed using peritoneal macrophages from WT or db/db mice.

RESULTS

MFG-E8 expression in granulation tissue in diabetic mice was significantly reduced compared with that in non-diabetic mice. We next examined the effect of subcutaneous injection of MFG-E8 WT/KO MSCs around the wound. Diabetic wound healing was significantly accelerated by the injection of MSCs. Diabetic wound healing in MFG-E8 KO MSCs-injected wounds was significantly delayed compared to that in WT MSCs-injected wounds. The numbers of CD31⁺ EC and NG2⁺ pericytes, as well as M2 macrophages in wounds in KO MSCs-injected mice were significantly decreased. MFG-E8 WT MSCs treatment suppressed the number of apoptotic cells and TNF-α⁺ cells in wounds. In an in vitro assay, MFG-E8 WT MSCs-conditioned medium enhanced phagocytosis of apoptotic cells by peritoneal macrophages from diabetic mice.

CONCLUSION

MSCs-derived MFG-E8 might accelerate diabetic wound healing by promoting angiogenesis, the clearance of apoptotic cells, and the infiltration of M2 macrophages, and by suppressing inflammatory cytokines in wound area.

Hyperglycaemia inhibits REG3A expression to exacerbate TLR3-mediated skin inflammation in diabetes

Dysregulated inflammatory responses are known to impair wound healing in diabetes, but the underlying mechanisms are poorly understood. Here we show that the antimicrobial protein REG3A controls TLR3-mediated inflammation after skin injury. This control is mediated by REG3A-induced SHP-1 protein, and acts selectively on TLR3-activated JNK2. In diabetic mouse skin, hyperglycaemia inhibits the expression of IL-17-induced IL-33 via glucose glycation. The decrease in cutaneous IL-33 reduces REG3A expression in epidermal keratinocytes. The reduction in REG3A is associated with lower levels of SHP-1, which normally inhibits TLR3-induced JNK2 phosphorylation, thereby increasing inflammation in skin wounds. To our knowledge, these findings show for the first time that REG3A can modulate specific cutaneous inflammatory responses and that the decrease in cutaneous REG3A exacerbates inflammation in diabetic skin wounds.

Patients with diabetes often have delayed wound healing, associated with excessive inflammation. Here the authors report that REG3A inhibits TLR3-driven inflammation in skin wounds, and show that REG3A is reduced in models of diabetes, which exacerbates inflammation in diabetic wounds.

Nonhealing Wounds—A Therapeutic Dilemma

Chronic wounds of the lower extremity are a therapeutic dilemma. In India, chronic wounds are caused by factors other than impaired circulation and diabetes, which account for most of this clinical problem in Western societies. A study of 2 topical agents, placental extract and phenytoin powder, is presented in this paper. One hundred fifty patients were randomly assigned to these treatments or to saline dressings (control). It was observed that patients receiving active topical treatments responded better than those in the control group. The importance of this finding should be viewed with the perspective that these topical treatments are inexpensive and easily available in India. The study also piloted measurements of angiogenic responses in 1 group, and the findings encourage further exploration with the technique and topical agent.

Neutrophil extracellular trap formation is elicited in response to cold physical plasma

Cold physical plasma is an ionized gas with a multitude of components, including hydrogen peroxide and other reactive oxygen and nitrogen species. Recent studies suggest that exposure of wounds to cold plasma may accelerate healing. Upon wounding, neutrophils are the first line of defense against invading microorganisms but have also been identified to play a role in delayed healing. In this study, we examined how plasma treatment affects the functions of peripheral blood neutrophils. Plasma treatment induced oxidative stress, as assessed by the oxidation of intracellular fluorescent redox probes; reduced metabolic activity; but did not induce early apoptosis. Neutrophil oxidative burst was only modestly affected after plasma treatment, and the killing of Pseudomonas aeruginosa and Staphylococcus aureus was not significantly affected. Intriguingly, we found that plasma induced profound extracellular trap formation. This was inhibited by the presence of catalase during plasma treatment but was not replicated by adding an equivalent concentration of hydrogen peroxide. Plasma-induced neutrophil extracellular trap formation was not dependent on the activity of myeloperoxidase or NADPH oxidase 2 but seemed to involve short-lived molecules. The amount of DNA release and the time course after plasma treatment were similar to that with the common neutrophil extracellular trap inducer PMA. After neutrophil extracellular traps had formed, concentrations of IL-8 were also significantly increased in supernatants of plasma-treated neutrophils. Both neutrophil extracellular traps and IL-8 release may aid antimicrobial activity and spur inflammation at the wound site. Whether this aids or exacerbates wound healing needs to be tested.

Current and emerging therapies in the management of diabetic foot ulcers

BACKGROUND

Diabetic foot ulcers are one of the major causes of mortality in diabetic patients. Very few drugs and therapies have regulatory approval for this indication and several agents from diverse pharmacological classes are currently in various phases of clinical trials for the management of diabetic foot ulcers.

SCOPE

The purpose of this review is to provide concise information of the drugs and therapies which are approved and present in clinical trials.

REVIEW METHODS

This review was carried out by systematic searches of relevant guidelines, patents, published articles, reviews and abstracts in PubMed/Medline, Web of Science, clinicaltrials.gov, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Google Scholar of all English language articles up to 1 March 2015. The following search terms were used: diabetes, diabetic foot, diabetic foot ulcer, diabetic wound, diabetic foot infections, wound management, randomized controlled trials, approved treatments, new treatments and clinical trials.

CONCLUSIONS

The various drugs and therapies for the management of diabetic foot ulcers comprise antibiotics, neuropathic drugs, wound dressings, skin substitutes, growth factors and inflammatory modulators. The majority of these therapies target the treatment of diabetic foot ulcers to address the altered biochemical composition of the diabetic wound. However, no single treatment can be definitively recommended for the treatment of diabetic foot ulcers.

Adipose-Derived Stem Cells Accelerate Diabetic Wound Healing through the Induction of Autocrine and Paracrine Effects

Cell-based therapy is an attractive approach for the treatment of chronic nonhealing wounds. This study investigated whether adipose-derived stem cells (ASCs) can accelerate diabetic wound healing and traffic in the engraftment of ASCs. Dorsal full-thickness skin wound defects (6 × 5 cm) were created in a streptozotocin (STZ)-induced diabetes rodent model. Group I served as a nondiabetic normal control, group II served as a diabetic control without ASCs, and group III included rats that were injected subcutaneously in the wound margin twice with nondiabetic ASCs (1 × 107 ASCs/dose). The wound healing was assessed clinically. Histological examination and immunohistochemical analyses of periwound tissue were performed. Green fluorescence protein (GFP)+-ASCs were used to examine the engraftment of these cells after injection. XenoLight DiR-labeled ASCs were implanted to detect migration ability using an IVIS imaging system. Results revealed that complete wound healing time statistically decreased in the ASC-treated group compared to the controls (p < 0.001). Histological examination revealed the ASC-treated group showed a significant reduction in the proinflammatory reaction, with significantly increased levels of EGF, VEGF, rPH, and Ki-67 expression compared to the controls. The populations of GFP+-ASCs in circulating blood significantly increased after ASC injection compared to those of controls. Immunofluorescence staining showed GFP+-ASCs significantly accumulated in the subdermal layer of the wound margin and increased angiogenesis via vWF and VEGF expression after injection. IVIS analysis revealed ASCs could exist and home into the periwound area up to 8 weeks postimplantation. In conclusion, ASCs significantly enhanced diabetic wound healing, engrafted into the local wound tissue, and implanted into circulating blood. ASC treatment stimulated neoangiogenesis and increased tissue regeneration through paracrine and autocrine mechanisms.

Chemokines in Wound Healing and as Potential Therapeutic Targets for Reducing Cutaneous Scarring

Significance: Cutaneous scarring is an almost inevitable end point of adult human wound healing. It is associated with significant morbidity, both physical and psychological. Pathological scarring, including hypertrophic and keloid scars, can be particularly debilitating. Manipulation of the chemokine system may lead to effective therapies for problematic lesions. Recent Advances: Rapid advancement in the understanding of chemokines and their receptors has led to exciting developments in the world of therapeutics. Modulation of their function has led to clinically effective treatments for conditions as diverse as human immunodeficiency virus and inflammatory bowel disease. Potential methods of targeting chemokines include monoclonal antibodies, small-molecule antagonists, interference with glycosaminoglycan binding and the use of synthetic truncated chemokines. Early work has shown promising results on scar development and appearance when the chemokine system is manipulated. Critical Issues: Chemokines are implicated in all stages of wound healing leading to the development of a cutaneous scar. An understanding of entirely regenerative wound healing in the developing fetus and how the expression of chemokines and their receptors change during the transition to the adult phenotype is central to addressing pathological scarring in adults. Future Directions: As our understanding of chemokine/receptor interactions and scar formation evolves it has become apparent that effective therapies will need to mirror the complexities in these diverse biological processes. It is likely that sophisticated treatments that sequentially influence multiple ligand/receptor interactions throughout all stages of wound healing will be required to deliver viable treatment options.

Negative pressure wound therapy as an adjunct in healing of chronic wounds

Negative pressure wound therapy (NPWT) has emerged as a cutting-edge technology and provides an alternative solution to the problem of wounds. This study was undertaken to assess the efficacy of this technique in the treatment of chronic wounds. A prospective clinical study was used to evaluate our experience in use of NPWT in the healing of pressure ulcers and chronic wounds over 2 years. The primary end point of the study group was the time taken for appearance of healthy granulation tissue and full reepithelialisation without drainage. All patients with sepsis were excluded from the study. The statistical analysis of the data was carried out. Of the 60 patients studied, 41 had associated comorbidities including diabetes mellitus. The commonest site of occurrence was the lower limb. Coverage in the form of a flap was required at presentation in 63·33% of patients. However, after initiation of NPWT, none of them required the procedure and they healed spontaneously either by secondary intention or by skin grafting. The time taken for appearance of healthy granulation tissue was 14·36 ± 4·24 days. Complete healing of wounds occurred by 33·1 ± 10·22 days. There was a statistically significant difference in the volume of the wounds before and after the intervention (P = 0·000). Complications resulting from NPWT were minimal. This technique is an excellent adjunct to surgical debridement.