Effects of TLC-Ag dressings on skin inflammation

A Natural deep eutectic solvent as an effective material for dual debridement and antibiofilm effects in chronic wound treatment

In chronic wound treatment, the debridement of devitalized tissue and the eradication of the biofilm must balance aggressiveness with care to protect regenerating tissues. In this study, urea, a potent chaotropic molecule, was modulated through the formation of a Natural Deep Eutectic Solvent (NADES) with betaine to develop a new debriding material (BU) suitable for application into injured dermal tissues. To evaluate BU's debriding capacity, along with its antibiofilm effect and biocompatibility, pre-clinical to clinical methods were employed. In vitro determinations using artificial and clinical slough samples indicate that BU has a high debriding capacity. Additionally, BU's de-structuring effects lead to a strong antibiofilm capability, demonstrated by a reduced bacterial load compared to the antiseptic PHMB-Betaine or medical honey, evaluated in artificial slough and ex vivo human skin. Furthermore, BU's efficacy was evaluated in a murine model of diabetic wound, demonstrating significant effects on debriding and antibiofilm capacity, similar to those observed in PHMB-Betaine and medical honey-treated animals. Finally, BU was clinically evaluated in leg ulcers, showing superiority in reduction of bacterial load and wound area compared to honey, with no adverse effects. Thus, BU represents a simple and non-biocidal option that could contributes to chronic wound care.

Hyaluronic acid treatment versus standard of care in chronic wounds in a German setting: Cost-effectiveness analysis

Background and Aims

Chronic wounds are a major burden for worldwide health care systems. In the management of chronic wounds several strategies with innovative and active agents emerged in the past few years, such as hyaluronic acid containing wound dressings. Evidence comparing the cost-effectiveness of hyaluronan and standard of care dressings (hydrofiber with silver) is still missing. The aim of the study is thus, to assess the cost-effectiveness of hyaluronan versus standard of care dressings (hydrofiber with silver) in chronic wounds from a German statutory health insurance perspective.

Methods

A decision tree was modeled to quantify the cost and healing rate at 12 weeks for the hyaluronan and silver dressings strategies. Input parameters were collected literature-based, accounting for healing rates, dressing prices and prices for dressing changes and associated home care. Parameter uncertainty was accounted for by one-way and probabilistic sensitivity analysis.

Results

Hyaluronic acid showed a better healing rate (60.68%) and noticeable lower cost (749.80 Euro) compared to standard of care (silver containing) dressings (59.62%; 883.05 Euro), resulting in an Incremental Cost Effectiveness Ratio of -12,570.57. The hyaluronan approach is hence a dominant strategy in chronic wound management. Sensitivity analysis confirmed these results, giving a range of 60%- 70% of cost-effective scenarios.

Conclusions

Hyaluronic acid dressings showed to be a clinical more effective strategy at significantly lower cost in chronic wounds compared to standard of care (hydrofiber with silver).

TLC-Ag dressings: a prospective, multicentre study on 728 patients with wounds at risk of or with local infection

OBJECTIVE

This study aimed to evaluate the management of an unselected cohort of patients with wounds at risk of or with clinical signs of local infection, treated with two antimicrobial contact layers impregnated with silver (TLC-Ag healing matrix), under real-life conditions during the COVID-19 pandemic.

METHOD

A large, prospective, multicentre, observational study with two TLC-Ag dressings (UrgoTul Ag/Silver and UrgoTul Ag Lite Border, Laboratoires Urgo, France) was conducted in Germany between May 2020 and May 2021. The main outcomes included a description of the treated patients and their wound management, the changes in wound infection and wound healing outcomes over a maximum period of four weeks of treatment, as well as the overall clinical assessment of the performance, local tolerance and acceptability of dressings.

RESULTS

A total of 728 patients with wounds of various aetiologies and wound infection status were treated with the evaluated dressings in 39 centres for a mean duration of 26±19 days, with an intermediate visit conducted in 712 (97.8%) patients after a mean period of 12±9 days. At the initial visit, it was established that the majority of patients (60.4%) had a wound infection, while the remaining cohort presented first clinical signs of a local wound infection (25.1%) or were at risk of wound infection (13.2%) (unclear status in 1.2%). Throughout the study period, all the parameters of wound infection continuously decreased, resulting at the final visit in a reduction by 78.9% of the prevalence of local wound infections and by 72.0% of the clinical signs of wound infection, the most rapidly diminished clinical sign being wound deterioration. Concurrently, in terms of the healing process, 92.1% of the wounds healed or improved, 3.2% remained unchanged and 1.7% worsened (data missing for 3.0%), and an improvement of the periwound skin was reported in 65.7% of the patients. Overall, the two dressings were 'very well accepted' by the majority of patients, with no uncomfortable feeling at wearing and no pain at dressing removal, and were assessed by the physicians as 'very useful' in the majority of the cases with a 'very good' efficacy in terms of antimicrobial activity and promotion of the wound healing process. Similar results were reported regardless of the wound type treated or of the TLC-Ag dressing evaluated.

CONCLUSION

These results are consistent with previous clinical evidence on TLC-Ag dressings. They support the good efficacy, good tolerability and usefulness of these antimicrobial dressings in the management of patients with wounds at risk or with clinical signs of local infection, in association with appropriate standard of care.

Silver distribution in chronic wounds and the healing dynamics of chronic wounds treated with dressings containing silver and octenidine

Although silver is an efficient antimicrobial and is a widely used antiseptic in wound healing, previous studies have reported the cytotoxic in vitro effects of silver dressings. Moreover, few studies have addressed the distribution of silver in chronic wounds. The study compares the healing of chronic wounds treated with a standard-of-care silver dressing (Ag-CMC) and a dressing containing antiseptic octenidine (OCT-HA). Biopsies were taken from two wound areas before the commencement of treatment (baseline), after 2 weeks and after 6 weeks (the end of the study). We analyzed the histopathologic wound-healing score, silver distribution, and expression of selected genes. The wound-healing score improved significantly in the wounded area treated with OCT-HA after 2 weeks compared to the baseline and the Ag-CMC. The Ag-CMC wound areas improved after 6 weeks compared to the baseline. Moreover, collagen maturation and decreases in the granulocyte and macrophage counts were faster in the OCT-HA parts. Treatment with OCT-HA resulted in less wound slough. The silver, visualized via autometallography, penetrated approximately 2 mm into the wound tissue and associated around capillaries and ECM fibers, and was detected in phagocytes. The metallothionein gene expression was elevated in the Ag-CMC wound parts. This exploratory study determined the penetration of silver into human chronic wounds and changes in the distribution thereof during treatment. We observed that silver directly affects the cells in the wound and elevates the metallothionein gene expression. Octenidine and hyaluronan dressings provide a suitable alternative to silver and carboxymethyl cellulose dressings without supplying silver to the wound.

Lactobacillus salivarius LA307 and Lactobacillus rhamnosus LA305 attenuate skin inflammation in mice

Oral probiotics potential for the management of dermatological diseases is vast. However, results of available studies in skin diseases, such as atopic dermatitis (AD), are inconsistent, partly because probiotic effects are strain specific. Careful selection of probiotic strains is therefore indispensable to ensure efficacy of treatment. In this study, Lactobacillus salivarius LA307, Lactobacillus rhamnosus LA305 and Bifidobacterium bifidum PI22, three strains that were previously identified for their interesting immunomodulatory properties in allergy and/or colitis models, were assessed in the prevention of chronic skin inflammation induced by repeated applications of 12-O-tetradecanoylphorbol-13-acetate in hairless SKH-1 mice. Macroscopic and microscopic evaluation of skin lesions was performed together with measurements of serum levels of interleukin (IL)-1β, IL-6, tumour necrosis factor alpha (TNF-α), IL-17, IL-22, IL-10 and IL-4. Daily oral treatment with the three strains at the dose of 1×109 cfu/day for 3 weeks limited the development of chronic skin inflammation, the effects being strain dependent. Indeed the two Lactobacillus strains significantly limited the intensity of skin inflammation both at the macroscopic and microscopic levels. Macroscopic observations were correlated to the histological observations and the resulting microscopic score. This limitation of the development of AD-like skin lesions involved the modulation of cytokine production. Treatment with the two Lactobacillus strains induced a decrease in the serum levels of pro-inflammatory cytokines IL-1β, IL-6, TNF-α, IL-17, IL-22 and at the opposite an increase in the production of the anti-inflammatory cytokine IL-10 and also of IL-4. Globally, B. bifidum PI22 had lower benefits. These results obtained in mice suggest that L. salivarius LA307 and L. rhamnosus LA305 could be good candidates for preserving skin integrity and homeostasis via the modulation of the gut microbiota and that their use could be beneficial in dermatological conditions such as AD.

Shaping mycolactone for therapeutic use against inflammatory disorders

Inflammation adversely affects the health of millions of people worldwide, and there is an unmet medical need for better anti-inflammatory drugs. We evaluated the therapeutic interest of mycolactone, a polyketide-derived macrolide produced by Mycobacterium ulcerans. Bacterial production of mycolactone in human skin causes a combination of ulcerative, analgesic, and anti-inflammatory effects. Whereas ulcer formation is mediated by the proapoptotic activity of mycolactone on skin cells via hyperactivation of Wiskott-Aldrich syndrome proteins, analgesia results from neuronal hyperpolarization via signaling through angiotensin II type 2 receptors. Mycolactone also blunts the capacity of immune cells to produce inflammatory mediators by an independent mechanism of protein synthesis blockade. In an attempt to isolate the structural determinants of mycolactone's immunosuppressive activity, we screened a library of synthetic subunits of mycolactone for inhibition of cytokine production by activated T cells. The minimal structure retaining immunosuppressive activity was a truncated version of mycolactone, missing one of the two core-branched polyketide chains. This compound inhibited the inflammatory cytokine responses of human primary cells at noncytotoxic doses and bound to angiotensin II type 2 receptors comparably to mycolactone in vitro. Notably, it was considerably less toxic than mycolactone in human primary dermal fibroblasts modeling ulcerative activity. In mouse models of human diseases, it conferred systemic protection against chronic skin inflammation and inflammatory pain, with no apparent side effects. In addition to establishing the anti-inflammatory potency of mycolactone in vivo, our study therefore highlights the translational potential of mycolactone core-derived structures as prospective immunosuppressants.

Curbing Inflammation in Skin Wound Healing: A Review

Wound healing is a complex regulated process that results in skin scar formation in postnatal mammals. Chronic wounds are major medical problems that can confer devastating consequences. Currently, there are no treatments to prevent scarring. In the early fetus wounds heal without scarring and the healing process is characterized by relatively less inflammation compared to adults; therefore, research aimed at reducing the inflammatory process related to wound healing might speed healing and improve the final scar appearance.

The Anti-Inflammatory and Antibacterial Action of Nanocrystalline Silver and Manuka Honey on the Molecular Alternation of Diabetic Foot Ulcer: A Comprehensive Literature Review

Honey and silver have been used since ancient times for treating wounds. Their widespread clinical application has attracted attention in light of the increasing prevalence of antibiotic-resistant bacteria. While there have been a number of studies exploring the anti-inflammatory and antibacterial effects of manuka honey and nanocrystalline silver, their advantages and limitations with regard to the treatment of chronic wounds remain a subject of debate. The aim of this paper is to examine the evidence on the use of nanocrystalline silver and manuka honey for treating diabetic foot ulcers through a critical and comprehensive review of in vitro studies, animal studies, and in vivo studies. The findings from the in vitro and animal studies suggest that both agents have effective antibacterial actions. Their anti-inflammatory action and related impact on wound healing are unclear. Besides, there is no evidence to suggest that any topical agent is more effective for use in treating diabetic foot ulcer. Overall, high-quality, clinical human studies supported by findings from the molecular science on the use of manuka honey or nanocrystalline silver are lacking. There is a need for rigorously designed human clinical studies on the subject to fill this knowledge gap and guide clinical practice.