Anaerobic bacteria in chronic wounds: Roles in disease, infection and treatment failure

Infection is among the most common factors that impede wound healing, yet standard treatments routinely fail to resolve chronic wound infections. The chronic wound environment is largely hypoxic/anoxic, and wounds are predominantly colonised by facultative and obligate anaerobic bacteria. Oxygen (O2) limitation is an underappreciated driver of microbiota composition and behaviour in chronic wounds. In this perspective article, we examine how anaerobic bacteria and their distinct physiologies support persistent, antibiotic-recalcitrant infections. We describe the anaerobic energy metabolisms bacteria rely on for long-term survival in the wound environment, and why many antibiotics become less effective under hypoxic conditions. We also discuss obligate anaerobes, which are among the most prevalent taxa to colonise chronic wounds, yet their potential roles in influencing the microbial community and wound healing have been overlooked. All of the most common obligate anaerobes found in chronic wounds are opportunistic pathogens. We consider how these organisms persist in the wound environment and interface with host physiology to hinder wound healing processes or promote chronic inflammation. Finally, we apply our understanding of anaerobic physiologies to evaluate current treatment practices and to propose new strategies for treating chronic wound infections.

The efficacy of topical oxygen therapy for wound healing: A meta-analysis of randomized controlled trials and observational studies

In preclinical studies, topical oxygen treatment (TOT) was shown to enhance wound healing by applying supplemental oxygen topically to the surface of a moist wound at normobaric conditions. The objective of this systematic review and meta-analysis is to provide a thorough evaluation of published RCTs and observational studies that compare supplemental TOT with standard wound care. A total of 1077 studies were obtained from a variety of databases, including PubMed, ScienceDirect, Web of Science, ProQuest, Scopus, ClinicalTrials.gov, EU Clinical Trial Registers, and Preprints.org. The Jadad scale was employed to assess the reliability of RCT studies, while the Newcastle-Ottawa Scale (NOS) was employed to assess the quality of observational studies. Seven RCT studies (n = 692) and two controlled observational studies (n = 111) were analysed. The rate of healed wounds was 25.8% in the control group and 43.25% in the adjuvant TOT group, which shows the use of TOT significantly increased the number of healed wounds (RR = 1.77; 95% CI 1.18-2.64; p = 0.005). A significant decrease in the percentage of wound area was found in the TOT group in RCT studies (mean difference = 15.64; 95% CI 5.22-26.06; p = 0.003). In observational studies, the rate of healed wounds was 37.5% in the standard care group and 80.95% in the adjuvant TOT group, which shows a significant increase in the number of healed wounds in the adjuvant TOT group (RR = 2.15; 95% CI 1.46-3.15; p < 0.00001). Topical oxygen therapy is considered a great adjuvant therapy for chronic wound healing, particularly wounds with vascular compromise such as diabetic ulcers and pressure ulcers. Further studies on this topic are still needed as there are a lot of potential uses for this technology in various types of wounds.

Recent advances in the adjunctive management of diabetic foot ulcer: Focus on noninvasive technologies

Diabetic foot ulcer (DFU) is one of the most costly and serious complications of diabetes. Treatment of DFU is usually challenging and new approaches are required to improve the therapeutic efficiencies. This review aims to update new and upcoming adjunctive therapies with noninvasive characterization for DFU, focusing on bioactive dressings, bioengineered tissues, mesenchymal stem cell (MSC) based therapy, platelet and cytokine-based therapy, topical oxygen therapy, and some repurposed drugs such as hypoglycemic agents, blood pressure medications, phenytoin, vitamins, and magnesium. Although the mentioned therapies may contribute to the improvement of DFU to a certain extent, most of the evidence come from clinical trials with small sample size and inconsistent selections of DFU patients. Further studies with high design quality and adequate sample sizes are necessitated. In addition, no single approach would completely correct the complex pathogenesis of DFU. Reasonable selection and combination of these techniques should be considered.

Hypoxic environment of wounds and photosynthesis-based oxygen therapy

The hypoxic environment is among the most important factors that complicates the healing of chronic wounds, such as venous leg ulcers, pressure injuries and diabetic foot ulcers, which seriously affects the quality of life of patients. Various oxygen supply treatments are used in clinical practice to improve the hypoxic environment at the wound site. However, problems still occur, such as insufficient oxygen supply, short oxygen infusion time and potential biosafety risks. In recent years, artificial photosynthetic systems have become a research hotspot in the fields of materials and energy. Photosynthesis is expected to improve the oxygen level at wound sites and promote wound healing because the method provides a continuous oxygen supply and has good biosafety. In this paper, oxygen treatment methods for wounds are reviewed, and the oxygen supply principle and construction of artificial photosynthesis systems are described. Finally, research progress on the photosynthetic oxygen production system to promote wound healing is summarized.

M.O.I.S.T. Concept for the Local Therapy of Chronic Wounds: An International Update

Chronic wounds remain a significant clinical challenge both for those affected and for healthcare systems. The treatment is often comprised and complex. All patients should receive wound care that is integrated into a holistic approach involving local management that addresses the underlying etiology and provides for gold standard therapy to support healing, avoid complications and be more cost effective. There have been significant advances in medicine over the last few decades. The development of new technologies and therapeutics for the local treatment of wounds is also constantly increasing. To help standardize clinical practice with regard to the multitude of wound products, the M.O.I.S.T. concept was developed by a multidisciplinary expert group. The M stands for moisture balance, O for oxygen balance, I for infection control, S for supporting strategies, and T for tissue management. Since the M.O.I.S.T. concept, which originated in the German-speaking countries, is now intended to provide healthcare professionals with an adapted instrument to be used in clinical practice, and a recent update to the concept has been undertaken by a group of interdisciplinary experts to align it with international standards. The M.O.I.S.T. concept can now be used internationally both as an educational tool and for the practical implementation of modern local treatment concepts for patients with chronic wounds and can also be used in routine clinical practice.

Oxygen Delivery Biomaterials in Wound Healing Applications

Oxygen (O2 ) delivery biomaterials have attracted great interest in the treatment of chronic wounds due to their potential applications in local and continuous O2 generation and delivery, improving cell viability until vascularization occurs, promoting structural growth of new blood vessels, simulating collagen synthesis, killing bacteria and reducing hypoxia-induced tissue damage. Therefore, different types of O2 delivery biomaterials including thin polymer films, fibers, hydrogels, or nanocomposite hydrogels have been developed to provide controlled, sufficient and long-lasting O2 to prevent hypoxia and maintain cell viability until the engineered tissue is vascularized by the host system. These biomaterials are made by various approaches, such as encapsulating O2 releasing molecules into hydrogels, polymer microspheres and 3D printed hydrogel scaffolds and adsorbing O2 carrying reagents into polymer films of fibers. In this article, different O2 generating sources such as solid inorganic peroxides, liquid peroxides, and photosynthetic microalgae, and O2 carrying perfluorocarbons and hemoglobin are presented and the applications of O2 delivery biomaterials in promoting wound healing are discussed. Furthermore, challenges encountered and future perspectives are highlighted.

Adjunctive topical oxygen therapy in the management of complex diabetes-related wounds: A South African case study series

Diabetic foot ulcers (DFUs) are a prevalent complication of diabetes mellitus and are associated with significant morbidity and mortality. The essential role of oxygen in the treatment of DFUs is documented. Indicated for use on a variety of wound types, topical haemoglobin therapy (Granulox®) is a novel therapeutic technology that binds atmospheric oxygen and improves the availability of oxygen at the wound site. When used as part of the wound management strategy, this therapy helps to reduce inflammation, exudate and slough, and promotes wound healing. In South Africa, health resources, coordinated foot care and podiatry, and data on diabetic foot complications are limited. Twelve patient case studies assessing the impact of adding topical haemoglobin therapy to the management regimes for DFUs and surgical (post-amputation) wounds were undertaken in South Africa. Patients were aged 50-71 years, and all had diabetes mellitus. At baseline, the area of the wounds ranged from 10.2 to 149.6 cm2 with depths ranging from 0.2 to 0.9 cm. Clinical signs of wound infection and high levels of viscous exudate were recorded in all cases. Wound dressings were changed twice weekly and sharp debridement of the wound performed as necessary. The wounds were cleansed and then completely coated with a thin film of Granulox® and dressings applied. Treatment was monitored over periods ranging from 57 to 276 days, during which dressings were changed and Granulox® administered to the wounds, ranging from 16 to 79 times. During the period of evaluation, wound size steadily reduced (by 87.1-100%), the condition of the wound bed tissue and peri-wound skin improved, and clinical signs of wound infection steadily resolved. Wounds significantly improved in two patients, almost healed in six patients, and healed in four patients. All patients reported a reduction in malodour and pain; seven patients were pain-free at the final followup assessment. The overall impression of Granulox® was rated as 'very good' by the clinicians, who considered that Granulox® facilitated an increase in tissue viability, with the promotion of granulation tissue, and stimulated epithelialisation.

Consenso de expertos sobre la eficacia clínica y directrices sobre la terapia de oxígeno transdérmico continuo para la cicatrización de las heridas complejas o difíciles de cicatrizar

INTRODUCTION

Oxygen is pivotal for wound healing. Its lack or hypoxia can delay this process, especially in individuals with comorbidities, potentially resulting in complex or hard-to-heal wounds. The Colombian Association of Diabetes (ACD) and the Colombian Association of Internal Medicine (ACMI) collaborated with a diverse group of experts to provide recommendations on the efficacy and best practices of continuous transdermal oxygen therapy (TOTc) in the care of such wounds.

METHOD

A modified Delphi technique was employed to obtain controlled feedback and responses. Experts from various disciplines engaged in reviewing and discussing numerous relevant scientific studies, focusing on the role of TOTc in treating chronic ulcers.

RESULTS

Continuous transdermal oxygen therapy has proven to be an effective and safe treatment for chronic and/or hard-to-heal ulcers. This therapy directly addresses the wound's oxygen deficiency, providing an environment conducive to healing. Significant benefits were observed, including the acceleration of the healing process, wound size reduction, and an enhancement in patient quality of life. Its efficacy was found across various ulcer etiologies, underscoring its therapeutic versatility.

CONCLUSIONS

Continuous transdermal oxygen therapy is effective and safe for treating chronic and hard-to-heal ulcers. It's crucial to address each case individually and through a multidisciplinary approach to maximize this therapy's benefits. Both evidence and clinical experience back its utility across a variety of ulcer etiologies.

Pilot Study: The Effectiveness of Hyperbaric Oxygen Therapy in the Treatment of Periodontitis in Patients with Type 2 Diabetes

Periodontitis is a chronic inflammatory disease with multifactorial aetiology. The relationship between periodontal disease and systemic diseases such as diabetes, obesity, metabolic syndrome, atherosclerotic, cardiovascular disease, and cognitive disorders has been the subject of many studies. The purpose of this study was to evaluate the effectiveness of hyperbaric oxygen therapy on periodontal health in patients suffering from periodontitis and type 2 diabetes. The study was conducted with 14 patients. A total of 369 periodontal pockets in the study group and 431 in the control group were examined. For further analysis, the pockets were classified as moderately deep (4-5 mm) and deep (≥6 mm). All patients received standard non-surgical treatment: scaling and root planing (SRP). Additionally, a series of 30 hyperbaric chamber sessions was carried out in the study group. The following parameters were compared between groups: PD (probing depth), CAL (clinical attachment level), and BOP (bleeding on probing). The results of the study showed significantly better results in terms of PD reduction and CAL gain in the study group in comparison to the control group. Both groups showed a reduction in BOP (bleeding on probing) after treatment. The use of hyperbaric oxygen therapy seems to have considerable benefits in patients with type 2 diabetes.

Efficacy of Topical Wound Oxygen Therapy in Healing Chronic Diabetic Foot Ulcers: Systematic Review and Meta-Analysis

Objective: To conduct a systematic review and meta-analysis of recently published randomized controlled trials (RCTs) that employed the use of topical oxygen therapy (TOT) as an adjunct therapy in the treatment of Wagner 1 and 2 diabetic foot ulcers. Approach: Following a literature search of eligible studies from 2010 onward, four RCTs were included. Studies were analyzed for patient and wound characteristics, outcomes, risk of bias, and quality of the evidence assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. A random-effects meta-analysis for complete wound healing was carried out due to statistical heterogeneity of included studies. Results: Risk of bias judgment (RoB2 analysis) resulted in one low-risk trial and three trials with some risk. One study was determined to be the origin of the statistical heterogeneity. Pooled results showed statistical significance with a risk ratio (RR) of 1.59 (95% confidence interval [CI]: 1.07-2.37; p = 0.021). Sensitivity analysis, based on imputed values for missing outcomes, demonstrated that both the RR and 95% CIs changed little. The GRADE ratings for each domain were as follows: (a) risk of bias: moderate (3); (b) imprecision: moderate (2), high (1); (c) inconsistency: low (2), high (1); (d) indirectness: moderate (2), high (1); and (e) publication bias: moderate (1), high (2). Overall, the evidence was moderate. Innovation: Our study shows that TOT is a viable diabetic foot ulcer therapy. Conclusions: These data support the use of TOT for the treatment of chronic Wagner 1 or 2 diabetic foot ulcers in the absence of infection and ischemia.

H2O2-PLA-(Alg)2Ca Hydrogel Enriched in Matrigel® Promotes Diabetic Wound Healing

Hydrogel-based dressings exhibit suitable features for successful wound healing, including flexibility, high water-vapor permeability and moisture retention, and exudate absorption capacity. Moreover, enriching the hydrogel matrix with additional therapeutic components has the potential to generate synergistic results. Thus, the present study centered on diabetic wound healing using a Matrigel-enriched alginate hydrogel embedded with polylactic acid (PLA) microspheres containing hydrogen peroxide (H2O2). The synthesis and physicochemical characterization of the samples, performed to evidence their compositional and microstructural features, swelling, and oxygen-entrapping capacity, were reported. For investigating the three-fold goal of the designed dressings (i.e., releasing oxygen at the wound site and maintaining a moist environment for faster healing, ensuring the absorption of a significant amount of exudate, and providing biocompatibility), in vivo biological tests on wounds of diabetic mice were approached. Evaluating multiple aspects during the healing process, the obtained composite material proved its efficiency for wound dressing applications by accelerating wound healing and promoting angiogenesis in diabetic skin injuries.

[M.O.I.S.T. concept for the local therapy of chronic wounds]

The treatment of patients with chronic wounds is still an interdisciplinary and interprofessional challenge. The basis of successful therapy for these patients is based on causal treatment of the underlying, pathophysiologically relevant diseases. In addition, however, local wound therapy should always be provided to support wound healing and avoid complications. In order to better structure the multitude of wound products, the M.O.I.S.T. concept was developed by a multidisciplinary expert group of WundDACH, the umbrella organization of German-speaking professional societies. M describes, O oxygenation, I infection control, S support of the healing process and T tissue management.The M.O.I.S.T. concept is intended to provide healthcare professionals a guidance for systematic planning and also for education with regard to the local therapy of patients with chronic wounds. The 2022 update of this concept is now presented here for the first time.

Hyperbaric oxygen therapy augments ciprofloxacin effect against Pseudomonas aeruginosa biofilm infected chronic wounds in a mouse model

Introduction

Chronic wounds have a compromised microcirculation which leads to restricted gas exchange. The majority of these hypoxic wounds is infested with microorganisms congregating in biofilms which further hinders the antibiotic function. We speculate whether this process can be counteracted by hyperbaric oxygen therapy (HBOT).

Methodology

Twenty-eight BALB/c mice with third-degree burns were included in the analyses. Pseudomonas aeruginosa embedded in seaweed alginate beads was injected under the eschar to mimic a biofilm infected wound. Challenged mice were randomized to receive either 4 days with 1 x ciprofloxacin combined with 2 × 90 min HBOT at 2.8 standard atmosphere daily, 1 x ciprofloxacin as monotherapy or saline as placebo. The mice were clinically scored, and wound sizes were estimated by planimetry daily. Euthanasia was performed on day 8. Wounds were surgically removed in toto, homogenized and plated for quantitative bacteriology. Homogenate supernatants were used for cytokine analysis.

Results

P. aeruginosa was present in all wounds at euthanasia. A significant lower bacterial load was seen in the HBOT group compared to either the monotherapy ciprofloxacin group (p = 0.0008), or the placebo group (p < 0.0001). IL-1β level was significantly lower in the HBOT group compared to the placebo group (p = 0.0007). Both treatment groups had higher osteopontin levels than the placebo group (p = 0.002 and p = 0.004). The same pattern was seen in the S100A9 analysis (p = 0.01 and p = 0.008), whereas no differences were detected between the S100A8, the VEGF or the MMP8 levels in the three groups.

Conclusion

These findings show that HBOT improves the bactericidal activity of ciprofloxacin against P. aeruginosa wound biofilm in vivo. HBOT in addition to ciprofloxacin also modulates the host response to a less inflammatory phenotype.

Diabetic foot ulcer: Challenges and future

Diabetic foot ulcers (DFUs) have become one of the important causes of mortality and morbidity in patients with diabetes, and they are also a common cause of hospitalization, which places a heavy burden on patients and society. The prevention and treatment of DFUs requires multidisciplinary management. By controlling various risk factors, such as blood glucose levels, blood pressure, lipid levels and smoking cessation, local management of DFUs should be strengthened, such as debridement, dressing, revascularization, stem cell decompression and oxygen therapy. If necessary, systemic anti-infection treatment should be administered. We reviewed the progress in the clinical practice of treating DFUs in recent years, such as revascularization, wound repair, offloading, stem cell transplantation, and anti-infection treatment. We also summarized and prospectively analyzed some new technologies and measurements used in the treatment of DFUs and noted the future challenges and directions for the development of DFU treatments.

Reduced Hospitalizations and Amputations in Patients with Diabetic Foot Ulcers Treated with Cyclical Pressurized Topical Wound Oxygen Therapy: Real-World Outcomes

Background: This study sought to examine the real-world impact of multimodality cyclical-pressure topical wound oxygen therapy (TWO2) on hospitalizations and amputations in patients with diabetic foot ulcer (DFU) compared with patients without TWO2. Methods: We conducted a retrospective review of deidentified patient medical records at 2 U.S. Veterans Affairs hospitals between January 2012 and January 2020. DFU patients were assigned to TWO2 or NO TWO2 cohorts based on their treatment records. Patients received appropriate standard of care and may have received other advanced wound treatments, including skin substitutes, negative pressure wound therapy, and growth factors. Primary study outcomes were patients requiring hospitalization and/or amputation within 360 days of initial wound documentation. Findings: Among unmatched cohorts of 202 patients with DFU (91 TWO2, 111 NO TWO2), 6.6% and 12.1% of TWO2 patients had hospitalizations and amputations, respectively, compared with 54.1% and 41.4% of NO TWO2 patients within 360 days (p < 0.0001, p < 0.0001), representing 88% and 71% reductions. Among propensity score-matched cohorts of 140 DFU patients (70 TWO2, 70 NO TWO2), compared with NO TWO2, 82% fewer TWO2 patients were hospitalized (7.1% vs. 40.0%, p < 0.0001) and 73% fewer TWO2 patients had amputations (8.6% vs. 31.4%, p = 0.0007). Logistic regression among matched cohorts demonstrated nearly ninefold and fivefold higher risk of hospitalization and amputation, respectively, for NO TWO2 versus TWO2. Interpretation: This retrospective cohort study demonstrates that treating patients with DFU with TWO2 is associated with significant reductions in hospitalizations and amputations in the real-world setting.

Concurrent optical and magnetic stimulation therapy in patients with lower extremity hard-to-heal wounds

OBJECTIVE

The treatment of patients with hard-to-heal wounds represents a major multidisciplinary challenge. Therefore, the development and clinical validation of new technologies remains extremely important. The novel application of concurrent optical and magnetic stimulation (COMS) offers a promising noninvasive approach to support physiological wound healing processes, especially in hard-to-heal wounds.

METHOD

In a multicentre, prospective, comparative, clinical trial, patients with hard-to-heal wounds on lower extremities of different aetiologies were treated with COMS as an adjunct to standard of care (SOC). The primary endpoint was safety; secondary endpoints were wound healing, pain and wound-specific quality of life (Wound-QoL).

RESULTS

A total of 40 patients were enrolled in this study (intention to treat population (ITTP), n=40). Of these patients, 37 were included in the analysis of the primary endpoint (primary endpoint population, (PEP), n=37). A further subgroup of 30 patients was included in the analysis of the secondary endpoint (secondary endpoint population (SEP), n=30). Finally, the SEP was stratified regarding patients' responsiveness to SOC in an SOC non-responder subgroup (NRSG), n=21, and in an SOC responder subgroup (RSG), n=9. A total of 102 adverse events (AEs) were recorded, of which 96% were 'mild' or 'moderate', and 91% were either a singular or transient event. Only 11 AEs were serious and associated with inpatient treatments unrelated to the studied intervention. In the NRSG, reductions in wound size were found to be statistically significant within the different study periods. Additionally, an acceleration of the healing rate was detected between the baseline and the first four weeks of COMS treatment (p=0.041). The rate of near-complete and complete wound closure in the SEP after 12 weeks were 60% and 43%, respectively. Pain reduction across the treatment group was statistically significant (p≤0.002 for both the SEP and NRSG). The Wound-QoL score improved by 24% during the study (p=0.001).

CONCLUSION

In this study, COMS treatment for patients with hard-to-heal wounds on lower extremities was a safe and effective novel treatment option, especially for patients who did not respond to SOC.

Inflammatory Microenvironment of Skin Wounds

Wound healing is a dynamic and highly regulated process that can be separated into three overlapping and interdependent phases: inflammation, proliferation, and remodelling. This review focuses on the inflammation stage, as it is the key stage of wound healing and plays a vital role in the local immune response and determines the progression of wound healing. Inflammatory cells, the main effector cells of the inflammatory response, have been widely studied, but little attention has been paid to the immunomodulatory effects of wound healing in non-inflammatory cells and the extracellular matrix. In this review, we attempt to deepen our understanding of the wound-healing microenvironment in the inflammatory stage by focusing on the interactions between cells and the extracellular matrix, as well as their role in regulating the immune response during the inflammatory stage. We hope our findings will provide new ideas for promoting tissue regeneration through immune regulation.

Topical oxygen treatment relieves pain from hard-to-heal leg ulcers and improves healing: a case series

Managing painful hard-to-heal leg ulcers is challenging with current therapeutic options. Wounds are prone to being hypoxic, and the subsequent pain is often related to hypoxia. Hyperbaric oxygen therapy (HBOT) is used to treat hard-to-heal leg wounds by delivering 100% oxygen at a pressure 2-3 times higher than atmospheric pressure. Unfortunately, most patients cannot be offered HBOT because it is costly and needs to be applied at specialised centres. Therefore, topical continuous oxygen therapy (TCOT) is a novel alternative for continuous local oxygen delivery to wounds and is associated with improved wound healing; however, its effect on painful wounds is unknown. This retrospective study was conducted on 20 patients, of whom 17 had painful hard-to-heal leg ulcers. In 13 patients (76%) with painful ulcers, TCOT was associated with rapid and substantial pain alleviation. Also, eight (40%) of the patients' wounds healed entirely with TCOT. This study suggests that TCOT may represent a novel pain management device for hard-to-heal wounds.

Management of Diabetic Foot Ulcers Using Topical Oxygen Therapy: A Case Series

BACKGROUND AND AIM

Surgical and endovascular revascularization procedures along with hyperbaric oxygen therapy (HBOT) and topical oxygen therapy (TOT) for chronic oxygen-deprived wounds are standard care treatment protocols for diabetic foot ulcer (DFU). Topical developments in the delivery of topical oxygen therapy have made this a more feasible treatment in practice. The present case series highlights the efficacy of NATROX therapy as TOT in wound healing and the impact of increased oxygenation on ulcer healing in patients with diabetic foot ulcers.

METHODS

The TOT was evaluated in 6 patients with DFU who have applied NATROX topical oxygen delivery system for a period ranging from 6 weeks to 24 weeks at Kahel Specialized Centre, located in Olaya, Riyadh, Saudi Arabia.

RESULTS

The administration of TOT demonstrated complete wound healing in all the six patients who either had ulcers with minor amputation of toes/heel or had ulcers with other comorbidities in a range from 3 to 8 weeks.

CONCLUSION

NATROX therapy is an advanced topical oxygen delivery system compared to other conventional oxygen delivery systems; however, the study warrants further research to assess its potential applicability in DFU wound healing in large sample size and across the races.

Inflammatory Biomarkers as Predictors of Infected Diabetic Foot Ulcer

Diabetic foot ulcer infection is a crucial complication associated with lower-limb amputation and postoperative mortality in individuals with diabetes mellitus. Deciding if a diabetic foot ulcer is infected in a community setting is challenging without validated point-of-care tests. Early detection of infected diabetic foot ulcers can reduce the frequency of hospitalizations, the occurrence of disability, and chances of mortality. Inflammatory biomarkers are predictors of infected diabetic foot ulcers and lower-limb amputation. Procalcitonin, CRP, pentraxin-3, interleukin-6, and calprotectin may help distinguish uninfected from mildly infected diabetic foot ulcers and diagnose soft tissue infections, bone lesions, and sepsis in diabetic patients. Moreover, these biomarkers may be predictors of lower-limb amputation and postoperative mortality. The current management of infected diabetic foot ulcers is disappointing and unsatisfactory, both in preventing its development and halting and modifying its progression. The use of new (molecular) techniques for the identification of the IDFU has not yet to be proven superior to classic cultural techniques for the management of such patients. For clinicians, if the risk stratification of DFU can be obtained earlier in diabetic patients, the hospitalization, disability, and mortality rate will be reduced. For the practical application of these biomarkers, it is important to correlate these quantitative parameters with clinical symptoms. Based on clinical observations and inflammatory biomarker evaluation, it can be used to guide clinical treatment methods. This review details clinical information published during the past several decades and discusses inflammatory biomarkers that may determine the risk and level of infection of diabetic foot ulcers.

Oxygenated Nanocellulose-A Material Platform for Antibacterial Wound Dressing Devices

Both carboxylated cellulose nanofibrils (CNF) and dissolved oxygen (DO) have been reported to possess antibacterial properties. However, the combination for use as wound dressings against biofilm infections in chronic wounds is less known. The present study reports the development of oxygenated CNF dispersions that exhibit strong antibacterial effect. Carboxylated CNF dispersions with different oxidation levels were oxygenated by the OXY BIO System and tested for antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. The results reveal that the higher oxidation level of the CNFs, the better antibacterial effect. Scanning electron microscopy of bacterial biofilms revealed that a potential mechanism of action of the CNFs is the formation of a network surrounding and entrapping the bacteria. This effect is further potentiated by the oxygenation process. A CNF sample (concentration 0.6 wt %) that was oxygenated to a DO level of 46.4 mg/L demonstrated a strong antibacterial effect against S. aureus in vivo using a mouse model of surgical site infection. The oxygenated CNF dispersion reduced the bacterial survival by 71%, after 24 h treatment. The potent antibacterial effect indicates that oxygenated nanocellulose is a promising material for antibacterial wound dressings.

Carbon Nanotubes-Based Hydrogels for Bacterial Eradiation and Wound-Healing Applications

Biocompatible nanomaterials have attracted enormous interest for biomedical applications. Carbonaceous materials, including carbon nanotubes (CNTs), have been widely explored in wound healing and other applications because of their superior physicochemical and potential biomedical properties to the nanoscale level. CNTs-based hydrogels are widely used for wound-healing and antibacterial applications. CNTs-based materials exhibited improved antimicrobial, antibacterial, adhesive, antioxidants, and mechanical properties, which are beneficial for the wound-healing process. This review concisely discussed the preparation of CNTs-based hydrogels and their antibacterial and wound-healing applications. The conductive potential of CNTs and their derivatives is discussed. It has been observed that the conductivity of CNTs is profoundly affected by their structure, temperature, and functionalization. CNTs properties can be easily modified by surface functionalization. CNTs-based composite hydrogels demonstrated superior antibacterial potential to corresponding pure polymer hydrogels. The accelerated wound healing was observed with CNTs-based hydrogels.

Impact of topical oxygen therapy on diabetic foot ulcer healing rates: a systematic review

OBJECTIVE

The aim of this systematic review was to determine the impact of topical oxygen therapy (TOT) on diabetic foot ulcer (DFU) healing.

METHOD

Using systematic review methodology, we considered randomised controlled trials (RCTs), controlled trials, pilot studies and observational studies. The search was conducted in January 2019, using PubMed, CINAHL, Ovid, Cochrane, Web of Science and EMBASE databases. Data analysis was undertaken using RevMan and a narrative synthesis. The article titles were assessed by two authors independently, and the abstracts (when available) of the studies identified by the search strategy were screened for their eligibility, according to the inclusion and exclusion criteria. The full-text version of potentially relevant studies was obtained and two authors independently screened this against the inclusion criteria. Data were extracted using a predesigned extraction tool and all included studies were quality appraised using the Evidence-Based Librarianship checklist.

RESULTS

The search returned 565 records of which eight met the inclusion criteria. Of the included studies, three were set in single centre outpatient wound clinics, two studies were set in an outpatient wound care research clinic and three studies were multisite. Meta-analysis of four studies was undertaken. DFUs are >2 times more likely to heal with TOT than with standard care alone. The odds ratio (OR)=2.49 (95% confidence interval (CI): 1.59-3.90, p=0.00001). The remaining four studies also showed that using TOT increased healing rates. An included study reported that time to 50% DFU closure was significantly shorter in participants who received the TOT, mean 18.4 days versus 28.9 days in the sham therapy group (p=0.001). However, the validity of 65.5% of the eight studies was assessed as low.

CONCLUSION

The findings suggest that TOT enhances healing for patients with hard-to-heal DFUs when used with standard care. The results from the trials reviewed also indicate a benefit for patients over standard care alone. However, the sample sizes in the studies were generally small, thus, more RCTs are warranted to further validate these findings.

DECLARATION OF INTEREST

The authors have no conflicts of interest to declare.

A Pragmatic, Single-Center, Prospective, Randomized Controlled Trial of Adjunct Hemoglobin-Mediated Granulox Topical Oxygen Therapy Twice Weekly for Foot Ulcers

BACKGROUND

Achieving timely healing of foot ulcers can help avoid complications such as infection and amputation; topical oxygen therapy has shown promise in achieving this. We evaluated the clinical effectiveness of Granulox, a hemoglobin spray device designed to deliver oxygen to the surface of wounds, for the healing of foot ulcers.

METHODS

We conducted a single-center, prospective, randomized controlled trial comparing standard of care (once-weekly podiatric medical clinic visits) versus standard care plus adjunct Granulox therapy twice weekly in adults with foot ulcers. After a 2-week screening phase, patients in whom the index wound had healed by less than 50% were randomized 1:1. Outcome measures were collated during the trial phase at 6 and 12 weeks.

RESULTS

Of 79 patients enrolled, 38 were randomized. After 12 weeks, the median percentage wound size reduction compared with the size of the ulcer at the start of the trial phase was 100% for the control arm and 48% for the Granulox arm (P = .21, Mann-Whitney U test). In the former, eight of 14 foot ulcers had healed; in the latter, four of 15 (P = .14, Fisher exact test). In the control arm, two amputations and one withdrawal occurred, whereas in the Granulox arm, one unrelated death and five withdrawals were recorded.

CONCLUSIONS

We could not replicate the favorable healing associated with use of Granulox as published by others. Differences in wound chronicity and frequency of Granulox application might have influenced differences in study results. Granulox might perform best when used as an adjunct for treatment of chronic wounds at least 8 weeks old.

Topical Wound Oxygen Therapy in the Treatment of Chronic Diabetic Foot Ulcers

Oxygen is a critical component of many biological processes and is essential for wound healing. Chronic wounds are typically characterized as being hypoxic in that the partial pressure of oxygen (pO2) in the center of the wound is often below a critical threshold necessary to fully support those enzymatic processes necessary for tissue repair. Providing supplemental oxygen can effectively raise pO2 levels to better optimize functioning of these essential enzymes. While hyperbaric oxygen therapy has been well studied in this regard, comparative clinical studies have fallen short of providing clear evidence in support of this modality for healing chronic diabetic foot ulcers (DFU). Topical oxygen therapy (TOT) has been in clinical use for over 50 years with encouraging pre-clinical and clinical studies that have shown improved healing rates when compared to standard care. Nonetheless, TOT has heretofore been discounted as an unproven wound healing modality without theoretical or clinical evidence to support its use. This review shall provide a brief summary of the role of oxygen in wound healing and, specifically, discuss the different types of topical oxygen devices and associated studies that have convincingly shown their efficacy in healing chronic DFUs. The time has come for topical oxygen therapy to be embraced as a proven adjunctive modality in this regard.

Radiation ulcer treatment with hyperbaric oxygen therapy and haemoglobin spray: case report and literature review

OBJECTIVE

To explore the effectiveness of a combination of hyperbaric oxygen therapy and haemoglobin spray in radiation ulcer treatment.

METHOD

We reviewed the available literature and present a case report in which radiation ulcer was treated with a combination of hyperbaric oxygen therapy and haemoglobin spray.

RESULTS

After 30 sessions of hyperbaric oxygen therapy (2.4 ATA; 90 minutes each session) and administration of haemoglobin spray, the wounds showed gradual progress towards healing and a good granulating base was achieved. The wounds were closed after two months using a small split thickness skin graft.

CONCLUSION

A combination of hyperbaric oxygen therapy and haemoglobin spray was effective as a short course of treatment for radiation ulcers.

Therapeutic index for local infections score (TILI): a new diagnostic tool

OBJECTIVE

Local wound infections are a major challenge for patients and health professionals. Various diagnostic and therapeutic options are available. However, a generally accepted standard is still lacking in Europe. The aim was to develop an easy-to-use clinical score for the early detection of local wound infections, as a basis for decision-making on antiseptic therapy or decolonisation.

METHOD

An interdisciplinary and interprofessional panel of experts from seven European countries was brought together to discuss the various aspects of diagnosing local wound infections.

RESULTS

The result was the adoption of the Therapeutic Index for Local Infections (TILI) score, developed in Germany by Initiative Chronische Wunden e.V., specifically for health professionals not specialised in wound care. Available in six European languages, the TILI score could also be adapted for different European countries, depending on their specific national healthcare requirements. The six clinical criteria for local wound infection are erythema to surrounding skin; heat; oedema, induration or swelling; spontaneous pain or pressure pain; stalled wound healing; and increase and/or change in colour or smell of exudate. Meeting all criteria indicates that antiseptic wound therapy could be started. Regardless of these unspecific clinical signs, there are also health conditions for the clinical situation which are a direct indication for antimicrobial wound therapy. These include the presence of wound pathogens, such as meticillin-resistant Staphylococcus aureus, septic surgical wound or the presence of free pus.

CONCLUSION

The development of the new internationally adapted TILI score, which could also be used by any caregiver in daily practice to diagnose local infections in acute and hard-to-heal wounds, is the result of expert consensus. However, the score system has to be validated through a clinical evaluation. This is to be performed in expert centres throughout Europe.

Topical oxygen treatment relieves pain from hard-to-heal leg ulcers and improves healing: a case report

Pain from hard-to-heal wounds is common and challenging to manage with current therapies. Most hard-to-heal wounds show some degree of hypoxia that impairs healing and contributes to pain. Regular oxygen therapy is given in hyperbaric oxygen chambers and is costly, time-consuming and cannot be offered to most patients. Moreover, hyperbaric oxygen therapy (HBOT) only increases tissue oxygen for a short time and is given only for a few hours per week. Topical oxygen therapy (TOT) was introduced as an alternative and in this report we focus on topical continuous oxygen therapy (TCOT), which has been shown to be associated with healing of hard-to-heal ulcers. We report on a patient with type 1 diabetes with a painful hard-to-heal lower leg ulcer that failed to heal with standard wound dressings and that had insufficient response to pharmacological analgesia. The patient was on three different analgesics before treating the wound with TCOT. As the wound was considered hypoxic, due to longstanding diabetes and probable microangiopathy, TCOT was commenced. Within one week of treatment starting, the patient spontaneously ceased all his analgesics as he was free of pain; and after 2.5 months, the ulcer healed. The patient reported no adverse effects. In addition to promoting healing, TCOT may also be considered for its potential analgesic effects in hard-to-heal wound management.

Soluble ICAM-1 is modulated by hyperbaric oxygen treatment and correlates with disease severity and mortality in patients with necrotizing soft-tissue infection

HBO2 treatment may be a promising immunomodulatory agent by increasing sICAM-1, thereby lowering risk of collateral damage, especially in the most critically ill patients. sICAM-1 is associated with disease severity in NSTI as emphasized by significant correlations with SAPS II. Low sICAM-1 levels are an independent risk factor of 90-day mortality and appeared to give a good level of diagnostic accuracy, suggesting that sICAM-1 can be used as a prognostic biomarker for NSTI.

Comparative Evaluation of Different Chitosan Species and Derivatives as Candidate Biomaterials for Oxygen-Loaded Nanodroplet Formulations to Treat Chronic Wounds

Persistent hypoxia is a main clinical feature of chronic wounds. Intriguingly, oxygen-loaded nanodroplets (OLNDs), filled with oxygen-solving 2H,3H-decafluoropentane and shelled with polysaccharides, have been proposed as a promising tool to counteract hypoxia by releasing a clinically relevant oxygen amount in a time-sustained manner. Here, four different types of chitosan (low or medium weight (LW or MW), glycol-(G-), and methylglycol-(MG-) chitosan) were compared as candidate biopolymers for shell manufacturing. The aim of the work was to design OLND formulations with optimized physico-chemical characteristics, efficacy in oxygen release, and biocompatibility. All OLND formulations displayed spherical morphology, cationic surfaces, ≤500 nm diameters (with LW chitosan-shelled OLNDs being the smallest), high stability, good oxygen encapsulation efficiency, and prolonged oxygen release kinetics. Upon cellular internalization, LW, MW, and G-chitosan-shelled nanodroplets did not significantly affect the viability, health, or metabolic activity of human keratinocytes (HaCaT cell line). On the contrary, MG-chitosan-shelled nanodroplets showed very poor biocompatibility. Combining the physico-chemical and the biological results obtained, LW chitosan emerges as the best candidate biopolymer for future OLND application as a skin device to treat chronic wounds.

Integrin-mediated adhesive properties of neutrophils are reduced by hyperbaric oxygen therapy in patients with chronic non-healing wound

In recent years, several studies suggested that the ability of hyperbaric oxygen therapy (HBOT) to promote healing in patients with diabetic ulcers and chronic wounds is due to the reduction of inflammatory cytokines and to a significant decrease in neutrophils recruitment to the damaged area. α4 and β2 integrins are receptors mediating the neutrophil adhesion to the endothelium and the comprehension of the effects of hyperbaric oxygenation on their expression and functions in neutrophils could be of great importance for the design of novel therapeutic protocols focused on anti-inflammatory agents. In this study, the α4 and β2 integrins' expression and functions have been evaluated in human primary neutrophils obtained from patients with chronic non-healing wounds and undergoing a prolonged HBOT (150 kPa per 90 minutes). The effect of a peptidomimetic α4β1 integrin antagonist has been also analyzed under these conditions. A statistically significant decrease (68%) in β2 integrin expression on neutrophils was observed during the treatment with HBO and maintained one month after the last treatment, while α4 integrin levels remained unchanged. However, cell adhesion function of both neutrophilic integrins α4β1 and β2 was significantly reduced 70 and 67%, respectively), but α4β1 integrin was still sensitive to antagonist inhibition in the presence of fibronectin, suggesting that a combined therapy between HBOT and integrin antagonists could have greater antinflammatory efficacy.

Oxygen therapy: evidence base

The evidence base for the different methods of oxygen therapy ranges from systematic reviews and meta-analyses to case series evaluations. A common thread running through the assorted evidence is that oxygen therapy accelerates healing and reduces healing times. This article summarises the clinical evidence produced on this therapy.

Role of oxygen in wound healing

Not only does oxygen play an essential role in each stage of the wound healing process. It also helps to increases host resistance to infection. Any impairment to the oxygen supply can therefore delay healing. This article explores the affects of oxygen on the wound cells and tissue, and explains how an adequate supply is required for granulation tissue formation and epithelialisation to occur

Granulox-The Use of Topical Hemoglobin to Aid Wound Healing: A Literature Review and Case Series From Singapore

Chronic wounds are an increasing burden on health care globally, and tissue hypoxia is a common issue in such wounds. Granulox (SastoMed GmbH, Georgsmarienhütte, Germany) is designed to provide wound bases with supplemental oxygen through facilitated diffusion and aid the physiological wound-healing process. It is a topical hemoglobin wound spray that is applied after wound cleaning and debridement to ensure continuous oxygen supplementation for up to 72 hours. Compared with other forms of topical oxygen therapy that require portable devices, Granulox is a spray-on application and the patient experience is similar to the use of a conventional dressing. Current clinical evidence suggests that Granulox aids with both wound healing and with symptom relief in chronic wounds, but current literature is limited by small study populations and further larger studies are required.

A Multinational, Multicenter, Randomized, Double-Blinded, Placebo-Controlled Trial to Evaluate the Efficacy of Cyclical Topical Wound Oxygen (TWO2) Therapy in the Treatment of Chronic Diabetic Foot Ulcers: The TWO2 Study

OBJECTIVE

Topical oxygen has been used for the treatment of chronic wounds for more than 50 years. Its effectiveness remains disputed due to the limited number of robust high-quality investigations. The aim of this study was to assess the efficacy of multimodality cyclical pressure Topical Wound Oxygen (TWO2) home care therapy in healing refractory diabetic foot ulcers (DFUs) that had failed to heal with standard of care (SOC) alone.

RESEARCH DESIGN AND METHODS

Patients with diabetes and chronic DFUs were randomized (double-blind) to either active TWO2 therapy or sham control therapy-both in addition to optimal SOC. The primary outcome was the percentage of ulcers in each group achieving 100% healing at 12 weeks. A group sequential design was used for the study with three predetermined analyses and hard stopping rules once 73, 146, and ultimately 220 patients completed the 12-week treatment phase.

RESULTS

At the first analysis point, the active TWO2 arm was found to be superior to the sham arm, with a closure rate of 41.7% compared with 13.5%. This difference in outcome produced an odds ratio (OR) of 4.57 (97.8% CI 1.19, 17.57), P = 0.010. After adjustment for University of Texas Classification (UTC) ulcer grade, the OR increased to 6.00 (97.8% CI 1.44, 24.93), P = 0.004. Cox proportional hazards modeling, also after adjustment for UTC grade, demonstrated >4.5 times the likelihood to heal DFUs over 12 weeks compared with the sham arm with a hazard ratio of 4.66 (97.8% CI 1.36, 15.98), P = 0.004. At 12 months postenrollment, 56% of active arm ulcers were closed compared with 27% of the sham arm ulcers (P = 0.013).

CONCLUSIONS

This sham-controlled, double-blind randomized controlled trial demonstrates that, at both 12 weeks and 12 months, adjunctive cyclical pressurized TWO2 therapy was superior in healing chronic DFUs compared with optimal SOC alone.

Topical application of haemoglobin: a safety study

OBJECTIVE

Ischaemia is one of the biggest problems in wound healing. It causes chronic wounds and also prevents normal wound healing because the tissue is oxygen deprived. Most oxygen-supplying therapies are only feasible in a clinical setting, but topical haemoglobin applications, such as Granulox, can be used in a non-clinical setting. For home application, the haemoglobin solution is sprayed topically onto the wound using a pressurised ready-to-use device with a bag-on-valve system. Although this system does not mix product and propellant, the risk of product inhalation by the patient, user or bystanders has to be minimised. This safety study aimed to determine particle size and product concentration in the surroundings after application to determine if there is a risk that product particles enter the respiratory tract.

METHODS

Measurements were performed using a laser scattered light photometer and a Scanning Mobility Particle Sizer (SMPS)-Spectrometer at different distances from the measuring devices to determine the inhalation risk for a possible user, patient and bystander. At all measuring points the amount of particles, their size and the formation of dust were measured.

RESULTS

No nanoparticles or dust were created during the application of the haemoglobin spray. The concentrations of the measured particles are below the allowed limits defined by Austrian law.

CONCLUSION

There is no risk of inhaling nanoparticles or being exposed to harmful concentrations of larger particles of the tested product. All the product's ingredients can be degraded and excreted by the human body through natural pathways.

Irritative potency of selected wound antiseptics in the hen's egg test on chorioallantoic membrane to predict their compatibility to wounds

Antiseptics are being used for prevention of infections in acute wounds and for treatment of infections in acute and chronic wounds. However, some antiseptics' high tissue toxicity might delay the healing process. The aim of this study was to investigate the tissue toxicity of preferentially used wound antiseptics and the influence of antiphlogistic additives via the hen's egg test on the chorioallantoic membrane (HET-CAM). The HET-CAM is a semi-in-vivo method testing the tissue tolerability of wound antiseptics by evaluating the blood vessel reaction of the chorioallantoic membrane in terms of hemorrhage, vessel lysis, and coagulation. For each test day, selected test substances were applied on the membranes of two to three eggs according to the test protocol. The overall irritation was then evaluated by referring to a calculated score. Normal distribution of the resulting scores was confirmed by D'Agostino-Pearson omnibus K2 test. Significant differences between the antiseptics were calculated by Tukey's multiple comparisons test. Severe CAM reactions were observed after short-term application of octenidine based wound gel (0.05%) and chlorhexidine digluconate (0.5% solution), moderate reactions for octenidine (0.05%) in aqueous solution combined with dexpanthenol (1.34%) and allantoin (0.2%) or for hydrogen peroxide (1.5% and 0.5%) in aqueous solution, slight reactions were observed for hydrogen peroxide (1.5%) in aqueous solution in combination with sodium thiocyanate (0.698%) and for the combination of NaOCl/HOCl (each 0.004%). Polyhexanide (0.04%) in Ringer solution and polyhexanide (0.05%) in Lipofundin, the hemoglobin spray (10%), dexpanthenol, and allantoin showed no irritation. The HET-CAM qualifies as a primary screening test for tissue tolerance of wound antiseptics. Regarding local tolerability, polyhexanide and hypochlorite are superior to other antiseptics.

Topical oxygen therapy stimulates healing in difficult, chronic wounds: a tertiary centre experience

OBJECTIVE

Oxygen plays a central role in wound healing. Recent technological advances have miniaturised oxygen delivery systems, with novel topical oxygen therapy allowing patients to receive oxygen therapy 24 hours a day while remaining completely mobile. Here we aim to examine the efficacy and safety of continuous topical oxygen diffusion in a 'real-world' setting.

METHODS

Topical oxygen therapy (TOT) was evaluated in patients with chronic, non-healing wounds in a tertiary referral specialist clinic.

RESULTS

The mean wound duration before TOT was 15 months. Regardless of treatment duration, in this previously non-healing group complete wound closure was observed in 32% of the total patients treated with the TOT device. However, optimal wound healing occurred when the device was used for >25 days, with an 83% wound area reduction and 47% wound closure rate seen in venous leg ulcers (VLUs) and a 74% reduction and a 57% wound closure rate in arterial foot ulcers.

CONCLUSION

Use of TOT in chronic wounds stimulates a healing state. In our study, almost half of the previously non-healing wounds closed.