Skin Microbiota and its Interplay with Wound Healing

Multifunctional moxifloxacin and essential oil loaded sodium alginate/thiolated karaya gum hydrogel dressings for improved wound healing

Numerous efforts have been done to develop wound dressings for effective wound treatment, remains a considerable challenge. The aim of current research work was to prepare multifunctional sodium alginate/thiolated karaya gum hydrogel dressings containing moxifloxacin in combination with artemesia/cedarwood essential oil. Thiolation of karaya gum was achieved by esterification reaction with 3 mercapto-propionic acid and synthesis of blended sodium alginate and thiolated karaya gum hydrogel films without (S1/TK1) and with moxifloxacin and artemesia/cedarwood oil (S1/TK1.DA1, S1/TK1.DC1) was achieved using solvent casting technique and were evaluated for fourier transform infrared spectrum and thermogravimetric analysis. Increasing the concentration of thiolated karaya gum substantially enhanced the bioadhesion, with a 350 % increase in bioadhesion-force and 353 % improvement in bond-strength while exhibiting balanced mechanical properties with an increase rate of 166 % in tensile strength and 73 % in percent-elongation. Incorporation of both moxifloxacin and artemesia/cedarwood oil also considerably enhanced the antibacterial activity of Optimized S1/TK1.DA1 and S1/TK1.DC1 formulations by 286 % and 253 % against s. aureus and 367 % and 269 % against e. coli respectively. Furthermore 2, 2 - di phenyl picryl hydrazyl (DPPH) and superoxide anion scavenging potential of S1/TK1.DA1 and S1/TK1.DC1 were enhanced by 1587 %, 1379 % and by 1384 % and 1245 % respectively. In vivo wound healing efficacy in cutaneous rat model also confirmed almost complete wound closure (≈ 99 %), collagen deposition and anti-inflammatory activity, enabling rapid wound recovery in twelve days. In conclusion, prepared hydrogel dressings might be an outstanding choice for wound healing applications.

Cold atmospheric plasma and skin wound healing: influence on microbial diversity and composition

BACKGROUND

Skin wound healing presents a complex challenge, often compounded by the risk of infection. Cold atmospheric plasma (CAP) emerged as a novel therapeutic for reducing bacterial load and expediting wound healing. However, its effect on the wound microbiome remained unclear. This study aimed to characterize the microbiome of different types of wounds and determine whether CAP influenced microbial diversity.

METHODS

Twenty-five patients (ten with acute, fifteen with chronic skin wounds) and ten healthy controls were enrolled. CAP was tailored to individual clinical conditions. Skin samples were collected before and after CAP, and microbiota composition was determined by 16 S ribosomal RNA sequencing.

RESULTS

Microbial communities differed between acute and chronic groups. CAP could accelerate wound healing. However, it did not change microbial α and β-diversity in acute wounds. In chronic wounds, α-diversity indices, including the chao and ACE, were significantly increased, and a significant clustering was observed in post-CAP group. In addition, CAP led to higher abundance of Staphylococcus, lower levels of Proteobacteria and Pseudomonas in chronic wounds.

CONCLUSIONS

This study provided novel insights into the impact of CAP on skin wound microbiota. Further research was required to ascertain causality between microbiota and CAP and to develop personalized CAP treatment strategies.

The relationship between the skin microbiome and probiotics in the healing of burn injuries

The relationship between the skin microbiome and probiotics in the healing of burn injuries has garnered significant attention in recent years. Burn injuries disrupt the delicate balance of the skin microbiome, leading to complications in the healing process. Probiotic therapies have emerged as promising interventions to restore microbial balance, inhibit biofilm formation, and accelerate tissue repair. Probiotics may also mitigate the risk of antibiotic-resistant infections, which is a major concern in burn units. By enhancing immune responses and stimulating the production of antimicrobial peptides, probiotics can effectively combat bacterial colonization and prevent the emergence of drug-resistant strains. A combination of probiotics with other therapies, such as phages or nanoparticles, holds significant promise for enhancing burn healing. This approach can effectively treat burn wounds by promoting wound healing synergy, preventing infection, modulating the immune response, and disrupting biofilms. Overall, the relationship between the skin microbiome and probiotics in burn wound healing has substantial potential to advance the field of burn wound management.

Association of the skin microbiome with the biomechanical scar properties in patients with burns

BACKGROUND AND OBJECTIVES

Skin microbiome dysbiosis can cause skin barrier dysfunction and stimulate scar property change. Skin barrier disruption post-burn injury leads to an imbalance in skin microbe diversity and distribution. We aimed to examine the changes in the skin microbiome of re-epithelialized burn scars.

MATERIAL AND METHODS

Twenty three patients were enrolled between January 2020 and July 2022. Twenty-six (13 Scar 1, immediately after complete wound healing; and 13 Scar 2, 3 months after complete wound healing) of seventy-eight scar skin samples (39 Scar 1 and 39 scar 2) qualified for analysis. Microbial community analysis was performed. Biomechanical scar properties of each patient and their correlation with skin microbiome were investigated.

RESULTS

The α-diversity of the scarred skin microbiome increased with time (Shannon's index, p = 0.029; Simpson's index, p = 0.009). The linear discriminant analysis effect size results showed that Bacteroides abundance decreased in scars after 3 months, whereas Campylobacter and Cutibacterium abundance increased. Campylobacter and Cutibacterium negatively and positively correlated with the final distensibility gross and biological elasticity, respectively. These results were consistent with the changes in the biomechanical properties of scars.

CONCLUSION

The scar skin microbial communities in patients with burns changed with biomechanical scar properties over time, and specific skin microorganisms correlated with biomechanical scar dynamics at the genus level.

γ-polyglutamic acid-encapsulated metformin-loaded Ga-Car-MOF and hydrocaffeic acid-modified chitosan double-layer microneedle patch for accelerated bacterial-infected wound healing

Bacteria deep in the wound can cause prolonged inflammation and dysfunctional angiogenesis, impeding healing and potentially leading to chronic conditions, disability, or even death. To address this, we developed a double-layer metal-organic framework (MOF) microneedle (MN) patch system (GCM-MN-CSH), designed to accelerate the healing of infected wounds through programmed therapy. The GCM-MN-CSH system consists of a hydrocaffeic acid-modified chitosan (CSH) hydrogel patch and a metformin (Met)-loaded Ga-Car-MOF (GCM)-based γ-polyglutamic acid matrix MN array (GCM-MN). The GCM nanoparticles were incorporated in the MN tips. The deep, localized penetration of GCM-MN, combined with the multifunctional activity of GCM, enables effective delivery of GCM nanoparticles into the dermis. These nanoparticles acid-response release Ga3+ ions and benzylpenicillin carboxylate, which possess antimicrobial activity, as well as Met, which promotes tissue regeneration. The adhesive CSH patch not only helps create a controlled, moist environment at the wound site but also provides antimicrobial properties on the surface. Together, the components of the GCM-MN-CSH system work synergistically to control infection, reduce inflammation, stimulate tissue proliferation, support tissue remodeling, and ultimately enable programmed wound healing. This advanced system offers a promising therapeutic platform for the management of infected wounds.

Bioactive Substances and Skin Health: An Integrative Review from a Pharmacy and Nutrition Perspective

The skin is one of the largest and most important organs of our body. There are numerous factors that are related to skin health, including lifestyle factors, nutrition, or skin care. Bioactive substances from plant and marine extracts play a key role in skin health. The aim of this research was to compile the main evidence on skin and bioactive substances. An integrative review was performed, reporting the main findings according to PRISMA (2020). Thirteen search equations were developed. After the applications of the equations and the process of screening and selection of articles, 95 references were compiled. The main results related to bioactive compounds were classified into food-derived components, nutraceuticals, symbiotics, active substances of marine origin, and substances from plant extracts). There are several factors that indicate that the use of bioactive compounds are interesting for skin health, highlighting some dietary nutrients, substances obtained from plant extracts and metabolites of marine origin that, showing anti-inflammatory and antimicrobial effects, are related to the improvement of some skin conditions or are active principles for cosmetics.

Preparation of antibacterial cellulose nanocrystals-graft-poly[2-(tert-butylamino) ethyl methacrylate] nanoparticles and their applications on creating wound dressings with a bacterial shielding property

Bacterial infections in wounds, especially in patients with chronic conditions like diabetic wounds, pose significant treatment challenges. Addressing the susceptibility to infection is crucial, and the development of functional dressings to prevent bacterial invasion has proven a promising strategy. Cellulose nanocrystals (CNCs), derived from bio-resources and functioning as nanoparticles (NPs), were modified with poly[2-(tert-butylamino) ethyl methacrylate] (PTA) through atom transfer radical polymerization (ATRP) to create CNCs-graft-PTA NPs (CNPs). Optimized CNPs exhibited enhanced antibacterial efficacy, excellent dispersity in environmentally friendly solvents, and notable biocompatibility. These CNPs were then applied to polypropylene non-woven fabrics (PPNWFs) via a straightforward dipping procedure. The integration of CNPs onto PPNWFs endowed them with exceptional antibacterial properties, a remarkable ability to shield against bacterial intrusion, and demonstrated biosafety through in vitro and in vivo assessments. With their desirable biomedical characteristics, CNP-modified PPNWFs emerge as a promising choice for the top layer in various functional dressings aimed at effectively treating wounds prone to infection.

Analysis of microbial environment changes in wound healing of pressure ulcers in rats promoted by moist exposed burn ointment

This study explored the effects of Moist Exposed Burn Ointment (MEBO) on the healing process of pressure-induced wounds. Using a stage IV pressure ulcer model established in 42 rats, divided equally into a control gel group and an MEBO group, we investigated the efficacy of MEBO through topical application. The control group received Carbomer gel, while the MEBO group was treated with MEBO until complete wound healing. Results showed that MEBO significantly accelerated wound healing compared to the control group. Histological analysis, including hematoxylin and eosin (HE) staining and Masson's trichrome staining, revealed enhanced epithelialization and collagen deposition in the MEBO group. Furthermore, 16S rRNA sequencing indicated that MEBO reduced microbial diversity at the wound site and reshaped the microbial composition. Notably, The increased abundance of Acinetobacter and Staphylococcus, coupled with a reduction in Pseudomonas, may reflect a shift in the wound microbiome that could be conducive to healing. However, the exact role of these microbial shifts in promoting wound healing requires further investigation, as microbial dynamics in wound environments are complex and context-dependent. These findings suggest that MEBO facilitates wound healing by optimizing the wound microbiome, thereby offering a promising therapeutic approach for managing pressure ulcers.

Low-temperature cold plasma promotes wound healing by inhibiting skin inflammation and improving skin microbiome

Wound healing includes four consecutive and overlapping stages of hemostasis, inflammation, proliferation, and remodeling. Factors such as aging, infection, and chronic diseases can lead to chronic wounds and delayed healing. Low-temperature cold plasma (LTCP) is an emerging physical therapy for wound healing, characterized by its safety, environmental friendliness, and ease of operation. This study utilized a self-developed LTCP device to investigate its biological effects and mechanisms on wound healing in adult and elderly mice. Histopathological studies found that LTCP significantly accelerated the healing rate of skin wounds in mice, with particularly pronounced effects in elderly mice. LTCP can markedly inhibit the expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and senescence-associated secretory phenotype factors (MMP-3, MMP-9), while significantly increasing the expression of tissue repair-related factors, such as VEGF, bFGF, TGF-β, COL-I, and α-SMA. It also regulated the expression of genes related to cell proliferation and migration (Aqp5, Spint1), inflammation response (Nlrp3, Icam1), and angiogenesis (Ptx3, Thbs1), promoting cell proliferation and inhibit apoptosis. Furthermore, LTCP treatment reduced the relative abundance of harmful bacteria such as Delftia, Stenotrophomonas, Enterococcus, and Enterobacter in skin wounds, while increasing the relative abundance of beneficial bacteria such as Muribaculaceae, Acinetobacter, Lachnospiraceae NK4A136_group, and un_f__Lachnospiraceae, thereby improving the microbial community structure of skin wounds. These research findings are of significant implications for understanding the mechanism of skin wound healing, as well as for the treatment and clinical applications of skin wounds, especially aging skin.

Integrative multi-omics analysis of radionuclide-induced intestinal injury reveals the radioprotective role of L-citrulline through histone H3-mediated Cxcl3

BACKGROUND

The widespread application of nuclear technology has markedly heightened the risk of extensive, uncontrolled exposure to radiation. Nevertheless, in contrast to external irradiation, the biological impacts and countermeasures against internal irradiation from radionuclides remain inadequately characterized.

METHODS

Mice were administered yttrium-90 (Y90) carbon microspheres via gavage at different dosages (0-5.0 mCi) to establish a radionuclides exposure model. A multi-omics analysis was employed to access alterations in gut microbiota, fecal and colonic metabolites profiles, and intestinal mRNA expression post-irradiation. The function of significant metabolite was validated at both cellular levels and organismal levels. Additionally, ChIP-Seq and RNA-Seq techniques were utilized to investigate the molecular mechanism underlying the actions of key metabolite.

RESULTS

Exposure to Y90 resulted in intestinal damage and hematological impairment. Multi-omics analysis revealed significant alternations of gut microbiota, fecal metabolites, colonic metabolites, and intestinal mRNA expression following internal radiation exposure. Notably, L-citrulline was identified as a metabolite with changes observed in both fecal and colonic tissues, demonstrating radioprotective properties in vitro and in vivo. Mechanistically, L-citrulline facilitated the citrullination of histone H3 at the 17th site (H3Cit17), and multiple mRNAs including C-X-C motif chemokine ligand 3 (Cxcl3), were transcriptionally regulated by H3Cit17 post L-citrulline treatment. Furthermore, Cxcl3 conferred protective effects for intestinal epithelial cells against ionizing radiation.

CONCLUSIONS

The research offers critical perspectives on the intestinal and gut microbiota's reaction to radionuclides exposure. It underscores the promise of L-citrulline as a radioprotective compound, which may have substantial ramifications for the formulation of strategies to mitigate radiation exposure.

Out of this World: Wound Healing on Earth and in Space

Impaired wound healing is a significant concern for humans in space, where the unique microgravity environment poses challenges to the natural healing processes of the body. Similar to chronic wounds on earth, such as diabetic foot ulcers and venous leg ulcers, wounds inflicted in space exhibit delayed or impaired healing responses. These wounds share common features, including dysregulated cellular signaling, altered cytokine profiles, and impaired tissue regeneration. Little is known about the mechanisms underlying wound healing under microgravity. In this review, we focused on exploring the parallels between wound healing in space and chronic wounds on earth as a fundamental approach for developing effective countermeasures to promote healing and mitigate associated health risks during long-space missions.

Pressure injuries and biofilms: Microbiome, model systems and therapies

Chronic wounds have emerged as significant clinical problems owing to their increasing incidence and greater recognition of associated morbidity and socio-economic burden. They are defined as wounds that do not progress normally through the stages of healing in a timely and/or orderly manner. Pressure injuries, in particular, represent a serious problem for patients who are elderly or have limited mobility, such as wheelchair users or those who spend most of the day in bed. These injuries often result from prolonged pressure exerted on the skin over the bone. Treatment of pressure injuries is complex and costly. Emerging evidence suggests that the pressure injury microbiome plays a vital role in chronic wound formation and delaying wound healing. Additionally, antibiotics often fail due to the formation of resistant biofilms and the emergence of antimicrobial-resistant bacteria. In this review, we will summarise the current knowledge on: (a) biofilms and microbiomes in pressure injuries; (b) in vitro and in vivo model systems to study pressure injuries, and (c) current therapies and novel treatment approaches. Understanding the complex interactions between microbes and the host immune system in pressure injuries will provide valuable insights to improve patient outcomes.

Non-antibiotic approaches to mitigating wound infections: Potential for SSRIs and adrenergic antagonists as emerging therapeutics

Bacterial biofilms represent a formidable challenge in the treatment of chronic wounds, largely because of their resistance to conventional antibiotics. The emergence of multidrug-resistant (MDR) bacterial strains exacerbates this issue, necessitating a shift towards exploring alternative therapeutic approaches. In response to this urgent need, there has been a surge in research efforts aimed at identifying effective non-antibiotic treatments. Recently noted among the non-antibiotic options are selective serotonin reuptake inhibitors (SSRIs) and beta-adrenergic (β-AR) antagonists. Both have demonstrated antimicrobial activities and wound-healing properties, which makes them particularly promising potential therapeutics for chronic wounds. This review seeks to comprehensively evaluate the landscape of non-antibiotic strategies for managing wound infections. By analysing the latest research findings and clinical developments, it aims to shed light on emerging therapeutic alternatives. Additionally, the review delves into the potential of repurposing systemic therapeutics for topical application, offering insights into the feasibility and challenges associated with current approaches. We also address the necessity of translating promising preclinical results into tangible clinical benefits.

Dynamics of Human Palatal Wound Healing and the Associated Microbiome

Wound healing in the oral mucosa is superior to that in the skin, with faster wound closure accompanied by reduced inflammation, less angiogenesis, and minimal scar formation. A well-characterized oral wound model is critical to investigating the mechanisms of oral wound closure and the efficacy of various clinical interventions. Currently, there are a few human oral wound models, although none of them are well characterized. In the present study, we describe and characterize a human hard palate wound healing model. A 3.5-mm circular and two 1 × 5-mm rectangular full-thickness wounds were made in the first and second molar region, 5 mm from the gingival margin, on the hard palate of human subjects. The circular wound was used to monitor wound closure and collect swabs for a microbiome analysis via 16s rRNA sequencing. The rectangular wounds were biopsied and the tissue was used to evaluate the gene expression of wound healing-related mediators by real-time polymerase chain reaction. Saliva was also collected to examine the protein levels of similar molecules by enzyme-linked immunosorbent assays. Circular wounds were nearly closed on day 7 after wounding. Significant changes in the gene expression of inflammatory cytokines, growth factors, antimicrobial peptides, and extracellular matrix-related molecules were identified in day 1 and day 3 wound tissue and compared with unwounded tissue on day 0. Changes in the protein levels of various mediators were limited in the saliva. In addition, alpha diversity, beta diversity, and differential microbiome analysis demonstrated significant changes in bacterial colonization of the wound surface over time compared with unwounded mucosa. In summary, we comprehensively characterize a human hard palate wound-healing model that details the dynamic changes of wound closure, levels of wound healing-related mediators in the wound and saliva, and the oral wound microbiome.

The Wound Reporting in Animal and Human Preclinical Studies (WRAHPS) Guidelines

Preclinical studies for wound healing disorders are an essential step in translating discoveries into therapies. Also, they are an integral component of initial safety screening and gaining mechanistic insights using an in vivo approach. Given the complexity of the wound healing process, existing guidelines for animal testing do not capture key information due to the inevitable variability in experimental design. Variations in study interpretation are increased by complexities associated with wound aetiology, wounding procedure, multiple treatment conditions, wound assessment, and analysis, as well as lack of acknowledgement of limitation of the model used. Yet, no standards exist to guide reporting crucial experimental information required to interpret results in translational studies of wound healing. Consistency in reporting allows transparency, comparative, and meta-analysis studies and avoids repetition and redundancy. Therefore, there is a critical and unmet need to standardise reporting for preclinical wound studies. To aid in reporting experimental conditions, The Wound Reporting in Animal and Human Preclinical Studies (WRAHPS) Guidelines have now been created by the authors working with the Wound Care Collaborative Community (WCCC) GAPS group to provide a checklist and reporting template for the most frequently used preclinical models in support of development for human clinical trials for wound healing disorders. It is anticipated that the WRAHPS Guidelines will standardise comprehensive methods for reporting in scientific manuscripts and the wound healing field overall. This article is not intended to address regulatory requirements but is intended to provide general guidelines on important scientific considerations for such studies.

Activation of muscle amine functional groups using eutectic mixture to enhance tissue adhesiveness of injectable, conductive and therapeutic granular hydrogel for diabetic ulcer regeneration

Herein, Polydopamine-modified microgels and microgels incorporated with superficial epoxy groups were synthesized and applied as precursors for the fabrication of four granular hydrogels. To enhance the tissue adhesiveness, a ternary deep eutectic solvent was synthesized to activate the muscle amine functional groups facilitating the formation of robust NC bonds at ambient conditions. At a certain shear rate of 10 s-1, hydrogel DMG displayed a viscosity of 9×103 Pa/s, representing the highest complex viscosity among the tested hydrogels primarily driven by quinone groups in PDA which enhanced reversible interactions, thereby increasing particle cohesion. Moreover, the intersection point escalating from about 4×103 to approximately 9×104 as the concentration of DMG increased from 0 % (for MG) to 70% (7D3MG) by weight. There was a decrease in adhesion strength from 0.45 ± 0.08 N in MG to 0.39 ± 0.16 N, 0.35± 0.18 N, and 0.33 ± 0.15 N for 3D7MG, 7D3MG, and DMG respectively, suggesting that MG was capable of forming numerous covalent bonds, thereby enhancing its adhesion to the substrate. The type of eutectic mixture affected the electrical conductivity and a very important point was the changes in resistance value with time. For MG catalyzed by [DES]AZG, the resistance increased only by 1.3 % (from 3.37 to 3.81 kΩ) at day 3 and 37.09 % (from 3.37 to 4.62 kΩ) at day 5. The 3D7MG hydrogel exhibited superior therapeutic efficacy toward diabetic wound regeneration. The proliferation index value for 3D7MG-[DES]AZG and 3D7MG-[DES]AG were calculated 42.3 % and 58.6 %, respectively, while the control group exhibited a lower value of 37.8 %.

Rosuvastatin accelerates the healing process of partial-thickness burn wounds in rats by reducing TNF-α levels

Introduction

Burn wound healing is a complex, dynamic process that involves a coordinated cascade of cellular responses and phases. Inflammation, proliferation and remodeling are the main phases of tissue repair, while tumor necrosis factor α (TNF-α) and procalcitonin (PCT) seem to be important mediators affecting the inflammatory state. Our aim was to assess the effect of rosuvastatin on tissue repair after partial thickness burn injury in healthy animals.

Material and methods

In this randomized prospective experimental study, 36 male rats were randomly divided into two groups: placebo-treated (PG) and topical rosuvastatin-treated (SG). Under anesthesia, a partial-thickness burn trauma was induced in the dorsal region of the rats using an iron seal. Tissue samples were collected for histopathological examination as well.

Results

Variables of TNF-α, procalcitonin and macroscopic assessment were normally distributed between the two groups on all studied days. The expression of TNF-α was found to be lower in burn injuries treated with topical rosuvastatin in comparison with placebo-treated animals on days 3, 6 and 9. PCT values in rosuvastatin-treated subgroups were statistically significantly lower than in placebo subgroups. Upon macroscopic examination, a significantly smaller burnt area in the statin-treated group was detected compared to the non-statin group on all days, except for day 3. Histopathological examination demonstrated higher levels of mean neutrophil infiltration in the placebo group (day 3). Finally, fibroblast proliferation, angiogenesis and re-epithelization levels were noted to be higher after the topical application of rosuvastatin.

Conclusions

Rosuvastatin accelerated wound healing and down-regulated TNF-α and PCT levels.

Bacterial Communities and Their Role in Bacterial Infections

Since infections associated with microbial communities threaten human health, research is increasingly focusing on the development of biofilms and strategies to combat them. Bacterial communities may include bacteria of one or several species. Therefore, examining all the microbes and identifying individual community bacteria responsible for the infectious process is important. Rapid and accurate detection of bacterial pathogens is paramount in healthcare, food safety, and environmental monitoring. Here, we analyze biofilm composition and describe the main groups of pathogens whose presence in a microbial community leads to infection (Staphylococcus aureus, Enterococcus spp., Cutibacterium spp., bacteria of the HACEK, etc.). Particular attention is paid to bacterial communities that can lead to the development of device-associated infections, damage, and disruption of the normal functioning of medical devices, such as cardiovascular implants, biliary stents, neurological, orthopedic, urological and penile implants, etc. Special consideration is given to tissue-located bacterial biofilms in the oral cavity, lungs and lower respiratory tract, upper respiratory tract, middle ear, cardiovascular system, skeletal system, wound surface, and urogenital system. We also describe methods used to analyze the bacterial composition in biofilms, such as microbiologically testing, staining, microcolony formation, cellular and extracellular biofilm components, and other methods. Finally, we present ways to reduce the incidence of biofilm-caused infections.

Dysbiosis and Staphylococcus species over representation in the exit site skin microbiota of hemodialysis patients carrying tunneled cuffed central venous catheter

OBJECTIVES

Hemodialysis patients with end-stage renal disease (ESRD) are susceptible to infections and dysbiosis. Catheter-related infections are typically caused by opportunistic skin pathogens. This study aims to compare the skin microbiota changes around the exit site of tunneled cuffed catheters (peri-catheter group) and the contralateral site (control group).

METHODS

ESRD patients on hemodialysis were recruited. The skin microbiota were collected with moist skin swabs and analyzed using high-throughput sequencing of the 16S rDNA V3-V4 region. After denoising, de-replication, and removal of chimeras, the reads were assigned to zero-radius operational taxonomic units (ZOTU).

RESULTS

We found significantly reduced alpha diversity in the peri-catheter group compared to the control group, as indicated by the Shannon, Jost, and equitability indexes, but not by the Chao1 or richness indexes. Beta diversity analysis revealed significant deviation of the peri-catheter microbiota from its corresponding control group. There was an overrepresentation of Firmicutes and an underrepresentation of Actinobacteria, Proteobacteria, and Acidobacteria at the phylum level in the peri-catheter group. The most abundant ZOTU (Staphylococcus spp.) drastically increased, while Cutibacterium, a commensal bacterium, decreased in the peri-catheter group. Network analysis revealed that the skin microbiota demonstrated covariance with both local and biochemical factors.

CONCLUSIONS

In conclusion, there was significant skin microbiota dysbiosis at the exit sites compared to the control sites in ESRD dialysis patients. Managing skin dysbiosis represents a promising target in the prevention of catheter-related bacterial infections.

Postoperative Wound Care in Dermatologic Surgery: Update And Narrative Review

Dermatologic surgery is associated with a very low risk of complications. There is no widely accepted, evidence-based protocol with recommendations for postoperative wound care after dermatologic surgery. In this narrative review, we will be discussing the evidence on surgical wound care products and procedures. Overall, we found relatively few studies and, in many cases, a lack of statistically significant differences, possibly because of the low rate of complications. We'll be discussing the evidence on when we should initiate wound care procedures and their frequency, the type of ointment and antiseptics that should be applied, and the type of dressings that should be used. Despite the very few studies available on postoperative wound care following dermatologic surgery, there is sufficient evidence as to not recommend the use of prophylactic topical antibiotics. We also analyze the currently available evidence on surgical wound care in special situations, such as management of skin grafts, partial skin graft donor sites, xenografts/biomembranes, and surgical wounds to the legs.

Multi-drug resistant Staphylococcus epidermidis from chronic wounds impair healing in human wound model

Venous leg ulcers (VLUs) represent one of the most prevalent types of chronic wounds characterised by perturbed microbiome and biofilm-forming bacteria. As one of the most abundant skin-commensal, Staphylococcus epidermidis is known as beneficial for the host, however, some strains can form biofilms and hinder wound healing. In this study, S. epidermidis distribution in VLUs and associated resistome were analysed in ulcer tissue from patients. Virulence of S. epidermidis isolates from VLUs were evaluated by whole genome sequencing, antimicrobial susceptibility testing, in vitro biofilm and binding assays, and assessment of biofilm-forming capability and pro-inflammatory potential using human ex vivo wound model. We demonstrated that S. epidermidis isolates from VLUs inhibit re-epithelialization through biofilm-dependent induction of IL-1β, IL-8, and IL-6 which was in accordance with impaired healing outcomes observed in patients. High extracellular matrix binding ability of VLU isolates was associated with antimicrobial resistance and expression levels of the embp and sdrG, responsible for bacterial binding to fibrinogen and fibrin, respectively. Finally, we showed that S. epidermidis from VLUs demonstrate pathogenic features with ability to impair healing which underscores the emergence of treatment-resistant virulent lineages in patients with chronic ulcers.

[Translated article] Postoperative Wound Care in Dermatologic Surgery: Update And Narrative Review

Dermatologic surgery is associated with a very low risk of complications. There is no widely accepted, evidence-based protocol with recommendations for postoperative wound care after dermatologic surgery. In this narrative review, we will be discussing the evidence on surgical wound care products and procedures. Overall, we found relatively few studies and, in many cases, a lack of statistically significant differences, possibly because of the low rate of complications. We'll be discussing the evidence on when we should initiate wound care procedures and their frequency, the type of ointment and antiseptics that should be applied, and the type of dressings that should be used. Despite the very few studies available on postoperative wound care following dermatologic surgery, there is sufficient evidence as to not recommend the use of prophylactic topical antibiotics. We also analyze the currently available evidence on surgical wound care in special situations, such as management of skin grafts, partial skin graft donor sites, xenografts/biomembranes, and surgical wounds to the legs.

The supplementation of mannan oligosaccharide in diet promotes the skin wound healing of juvenile turbot, Scophthalmus maximus

A 30-day feeding trial was conducted to investigate the effects of the supplementation of mannan oligosaccharide (MOS) in the diet on the skin wound healing process of juvenile turbot (Scophthalmus maximus). Two groups of diets were formulated, the control diet (CON) and the control diet supplemented with 0.16 % MOS (MOS), which were fed to the turbot separately. Each group had 3 replicates, with 20 fish per replicate. At the end of the feeding trial, all the fish were weighed and counted. Then four fish per tank were randomly selected for sampling, and the skin of the rest fish was wounded by a biopsy punch. The wounded fish continued to be fed as usual with the same diets respectively, and then sampled again at the 1, 3, and 7 day(s) post wounding (dpw). The results by image analysis showed that the wound closure rate of wounded fish was significantly improved by the supplementation of dietary MOS. As for the results of gene expression, dietary MOS promoted the expression of pro-inflammatory factors (il-1β & tnf-α) and decreased the expression of anti-inflammatory factors (tgf-β1 & il-10). It also enhanced the expression of genes related to re-epithelialization (mmp-9, fgf2, tgf-β1, rock1), as well as new tissue formation and remodeling (fn1, lamb2, col1-α, vegf). Furthermore, dietary MOS promoted re-epithelialization, cell proliferation, collagen deposition, and angiogenesis according to the histomorphological observation. In addition, the supplementation of MOS modified the communities of skin microbiota, decreasing the abundance of Rolstonia, Pseudomonas, and Aeromonas, while increasing the abundance of Pseudoalteromonas luteoviolacea and Shewanella colwellianav. In conclusion, the supplementation of dietary MOS (0.16 %) can promote the re-epithelialization and the recruitment of inflammatory cells, stimulate ECM biosynthesis and angiogenesis, modify the communities of skin microbiota, and ultimately promote the skin wound healing process.

Formulation and evaluation of n-acetyl cysteine loaded bi-polymeric physically crosslinked hydrogel with antibacterial and antioxidant activity for diabetic wound dressing

Diabetic wounds have become a serious global health concern, with a growing number of patients each year. Diabetic altered wound healing physiology, as well as resulting complications, make therapy difficult. Hence, diabetic wound healing necessitates a multidisciplinary strategy. This study focused on the formulation, statistical optimization, ex vivo, and in vitro evaluation of a diabetic wound healing by n-acetyl cysteine (NAC) loaded hydrogel. The objective of the study is to formulate n-acetyl loaded hydrogel with different ratio (1:1, 1:2, 1:3, 2:1) of sodium alginate and guar gum. The antibacterial and antifungal assessment against the viability of Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Staphylococcus aureus (S.aureus) and Candida albicans (C. albicans) was conducted after determining the in vitro drug release profile. The results of the experiment demonstrated that the formulation F3 was an optimal formulation on triplicate measurement with a pH of 6.2 ± 0.168, and a density of 1.026 ± 0.21. In vitro cell line study exhibited F3 has potential role in cell adhesion and proliferation might be beneficial to tissue regeneration and wound healing. The results imply that F3 may be helpful for the quick healing of diabetic wounds by promoting angiogenesis and also by scavenging free oxygen radicals.

Synergistic berberine chloride and Curcumin-Loaded nanofiber therapies against Methicillin-Resistant Staphylococcus aureus Infection: Augmented immune and inflammatory responses in zebrafish wound healing

BACKGROUND

Wound healing pivots on a finely orchestrated inflammatory cascade, critical for tissue repair. Chronic wounds, compounded by persistent inflammation and susceptibility to infection, pose formidable clinical challenges. Nanofiber dressings offer promising avenues for wound care, yet their interaction with inflammation and infection remains elusive. We aim to delineate the inflammatory cascade preceding wound closure and assess Cu@Bbc nanofibers' therapeutic efficacy in mitigating inflammation and combating infection. Their unique attributes suggest promise in modulating inflammation, fostering tissue regeneration, and preventing microbial colonization. Investigating the intricate interplay between nanofiber scaffolds, inflammation, and infection may unveil mechanisms of enhanced wound healing. Our findings could stimulate the development of tailored dressings, urgently needed for effective wound management amidst immune dysregulation, infection, and inflammation.

METHODS

In this investigation, we synthesized Cu@Bbc nanofibers, incorporating curcumin and berberine chloride, for wound healing applications. We evaluated their individual and combined antibacterial, anti-biofilm, and antioxidant activities, alongside binding affinity with pro-inflammatory cytokines through molecular docking. Morphological characterization was conducted via SEM, FTIR assessed functional groups, and wettability contact angle measured hydrophobic properties. The physical properties, including tensile strength, swelling behavior, and thermal stability, were evaluated using tensile testing, saline immersion method and thermogravimetric analysis. Biodegradability of the nanofibers was assessed through a soil burial test. Biocompatibility was determined via MTT assay, while wound healing efficacy was assessed with in vitro scratch assays. Controlled drug release and antibacterial activity against MRSA were examined, with in vivo assessment in a zebrafish model elucidating inflammatory responses and tissue remodeling.

RESULTS

In this study, the synergistic action of curcumin and berberine chloride exhibited potent antibacterial efficacy against MRSA, with significant anti-mature biofilm disruption. Additionally, the combination demonstrated heightened antioxidant potential. Molecular docking studies revealed strong binding affinity with pro-inflammatory cytokines, suggesting a role in expediting the inflammatory response crucial for wound healing. Morphological analysis confirmed nanofiber quality, with drug presence verified via FTIR spectroscopy. Cu@Bbc demonstrated higher tensile strength, optimal swelling behavior, and robust thermal stability as evaluated through tensile testing and thermogravimetric analysis. Additionally, the Cu@Bbc nanofiber showed enhanced biodegradability, as confirmed by the soil burial test. Biocompatibility assessments showed favorable compatibility, while in vitro studies demonstrated potent antibacterial activity. In vivo zebrafish experiments revealed accelerated wound closure, re-epithelialization, and heightened immune response, indicative of enhanced wound healing.

CONCLUSION

In summary, our investigation highlights the efficacy of Cu@Bbc nanofibers, laden with curcumin and berberine chloride, in displaying robust antibacterial and antioxidant attributes while also modulating immune responses and inflammatory cascades essential for wound healing. These results signify their potential as multifaceted wound dressings for clinical implementation.

Revealing the molecular mechanisms in wound healing and the effects of different physiological factors including diabetes, age, and stress

Wounds are the common fates in various microbial infections and physical damages including accidents, surgery, and burns. In response, a healthy body with a potent immune system heals that particular site within optimal time by following the coagulation, inflammation, proliferation, and remodeling phenomenon. However, certain malfunctions in the body due to various diseases particularly diabetes and other physiological factors like age, stress, etc., prolong the process of wound healing through various mechanisms including the Akt, Polyol, and Hexosamine pathways. The current review thoroughly explains the wound types, normal wound healing mechanisms, and the immune system's role. Moreover, the mechanistic role of diabetes is also elaborated comprehensively.

Does the use of DACC-coated dressings improve clinical outcomes for hard to heal wounds: A systematic review

Reports of overuse and antimicrobial resistance have fuelled some clinicians to adopt alternative wound dressings termed to be non-medicated or non-antimicrobials, which still claim antimicrobial or antibacterial activity. In this PROSPERO-registered systematic review, we evaluated the in vivo clinical evidence for the effectiveness of DACC-coated dressings in chronic, hard to heal wound-related outcomes. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Framework was adopted as the template in constructing this systematic review. The PICO format (Population [or patients], Intervention, Comparison [control], Outcome/s) was used to identify key clinical questions in determining patient outcomes under two domains (infection control and wound healing). A systematic search was performed in PubMed, OVID, Cochrane Library, clinical trial registries and data sources from independent committees. Abstracts of all studies were screened independently by two reviewers, with six further reviewers independently assessing records proceeding to full review. The authors rated the quality of evidence for each of the outcomes critical to decision making. After excluding duplicates, 748 records were screened from the databases, and 13 records were sought for full review. After full review, we excluded a further three records, leaving ten records for data extraction. Three records were narrative reviews, three systematic reviews, two prospective non-comparative before/after studies, one prospective head-to-head comparator cohort study and one retrospective head-to-head comparator cohort study. No RCTs or case versus control studies were identified. The overall quality of clinical evidence for the use of DACC-coated dressing to improve wound infection and wound healing outcomes was assessed as very low. There is an urgent unmet need to perform appropriately designed RCTs or case-control studies. The extracted data provide no clarity and have limited to no evidence to support that using a DACC-coated dressing improves wound infection or wound healing outcomes. Further, there is no evidence to suggest this therapy is either superior to standard of wound care or equivocal to topical antimicrobial agents in the management of infected hard to heal wounds.

Exploring the Wound Healing Potential of Hispidin

BACKGROUND

Hispidin, a polyphenol component mainly derived from the medicinal mushroom species Phellinus and Inonotus, shows promise for biomedical applications, yet its potential in wound healing remains largely unexplored. This research investigates the wound healing effects of hispidin through in vitro and in vivo experiments, while also evaluating its antimicrobial properties and safety profile.

METHODS

In vitro scratch assays were conducted to evaluate the impact of hispidin on the migration of NIH-3T3 cells. The wound healing potential of hispidin was assessed in rats using excision wounds, dead space wounds, and linear incisions, treated with various topical ointments including a simple ointment, 2.5% (w/w) and a 5% (w/w) hispidin ointment, and a 0.2% (w/w) nitrofurazone ointment, administered at 0.2 g daily for 14 days.

RESULTS

Hispidin demonstrated antimicrobial properties and was particularly effective against Staphylococcus epidermidis. Hispidin enhanced NIH-3T3 cell viability, and promoted wound closure in scratch assays, correlating with increased levels of FGF21, TGF-β1, EGF, and VEGF. In excision wound models, the 5% (w/w) hispidin ointment improved wound contraction, epithelialization, tissue regeneration, fibroblast activity, and angiogenesis. In the granulation tissue from dead space wound models, hispidin reduced pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) and lipid peroxidation, while increasing anti-inflammatory cytokines (IL-10) and antioxidant activities (SOD, GPx, CAT), along with connective tissue markers like hydroxyproline, hexosamine, and hexuronic acid. Hispidin also enhanced wound breaking strength in incision models. Acute dermal toxicity studies indicated no adverse effects at 2000 mg/kg.

CONCLUSIONS

These findings highlight hispidin's potential in wound care, demonstrating its antimicrobial, regenerative, and safety properties.

Microbial Dysbiosis in the Skin Microbiome and Its Psychological Consequences

The homeostasis of the skin microbiome can be disrupted by both extrinsic and intrinsic factors, leading to a state of dysbiosis. This imbalance has been observed at the onset of persistent skin diseases that are closely linked to mental health conditions like anxiety and depression. This narrative review explores recent findings on the relationship between the skin microbiome and the pathophysiology of specific skin disorders, including acne vulgaris, atopic dermatitis, psoriasis, and wound infections. Additionally, it examines the psychological impact of these skin disorders, emphasizing their effect on patients' quality of life and their association with significant psychological consequences, such as anxiety, depression, stress, and suicidal ideation in the most severe cases.

Reshaped commensal wound microbiome via topical application of Calvatia gigantea extract contributes to faster diabetic wound healing

Background

Calvatia gigantea (CG) is widely used as a traditional Chinese medicine for wound treatment. In this study, we aimed to determine the effects of CG extract (CGE) on diabetic wound healing and the commensal wound microbiome.

Method

A wound model was established using leptin receptor-deficient db/db mice, with untreated mice as the control group and CGE-treated mice as the treatment group. The wound healing rate, inflammation and histology were analyzed. Additionally, wound microbiome was evaluated via 16S ribosomal RNA (rRNA) gene sequencing.

Results

CGE significantly accelerated the healing of diabetic ulcer wounds, facilitated re-epithelialization, and downregulated the transcription levels of the inflammatory cytokines, interleukin-1β and tumor necrosis factor-α. Furthermore, CGE treatment positively affected the wound microbiome, promoting diversity of the microbial community and enrichment of Escherichia-Shigella bacteria in the CGE-treated group.

Conclusions

Overall, CGE enhanced diabetic wound healing by modulating the wound microbiome and facilitating macrophage polarization during inflammation. These findings suggest modulation of the commensal wound microbiome using medicinal plants as a potential therapeutic strategy for diabetic wounds.

Bacterial fluorescence imaging as a predictor of skin graft integration in burn wounds

BACKGROUND

Split-thickness skin graft (STSG)1 integration rates are susceptible to improvement. Infection and/or biofilm should be appropriately addressed prior to grafting to improve the likelihood of graft-take. Incorporating technological aids such as fluorescence (FL)2 imaging (MolecuLight®), which accurately locates areas of bacterial loads above 104 CFU/gr, for graft site assessment and preparation could yield better outcomes.

METHODS

This single-center, prospective observational study included adult burn patients with previously infected wounds that had been deemed clinically and microbiologically clean and were therefore candidates for grafting. Prior to grafting, a FL imaging assessment (blinded to the surgical team) localized areas positive for moderate-high bacterial loads (>104 CFU/gr). Intra-operatively, a standard swab sample from the recipient site was collected by the surgical team. Postoperatively, areas positive/negative for FL and areas of graft take and failure were overlapped and measured (cm2) over a 2D schematic. The performance and accuracy of FL imaging and swab sampling in relation to graft outcomes were assessed.

RESULTS

38 patients were enrolled in the study. The mean total body surface area (TBSA)3 involvement was 14.5 ± 12.4 % [range 0.8 - 40.2 %]. 25/38 of the subjects enrolled had complete graft take while 13 had partial graft losses. There were no total losses. FL-imaging was positive in 100 % of losses versus 31 % (4/13) of the swab microbiology. FL-imaging was found to have a sensitivity of 86 %, specificity of 98 %, PPV of 72 %, NPV of 99 %, and an accuracy of 94 % for predicting any type or range of graft loss in the entire cohort. Meanwhile, the sensitivity of microbiology from swab samples was 30 %, with a specificity of 76 %.

CONCLUSIONS

FL imaging is an accurate method for assessing recipient sites and predicting the outcome of a skin graft among burn patients. These findings suggest that FL imaging can inform better decision-making surrounding grafts that may lead to better outcomes.

LEVEL OF EVIDENCE

Level IIA, Therapeutic study.

Lipopolysaccharide Derived from Pantoea agglomerans Directly Promotes the Migration of Human Keratinocytes

BACKGROUND/AIM

Because the skin is exposed to the external environment, it is important that wound healing processes proceed and terminate rapidly to minimize the risk of infection. A previous case report described the promotion of wound healing by transdermal administration of lipopolysaccharide derived from Pantoea agglomerans (LPSp). However, whether the wound healing-promoting effect of LPSp was due to direct activity on skin cells or indirect effects involving macrophages remained unclear. Therefore, this study investigated the wound healing-promoting effect of LPSp, particularly the promotion of keratinocyte migration.

MATERIALS AND METHODS

The migration of HaCaT human keratinocytes over time with and without LPSp was assayed using a cell migration assay kit. Migration was also analyzed using HaCaT cells treated with LPSp and an antibody against Toll-like receptor (TLR) 4, a receptor for LPS.

RESULTS

Addition of LPSp significantly enhanced cell migration compared to no LPSp addition. Migration was inhibited by the addition of anti-TLR4 antibody.

CONCLUSION

LPSp acts directly on epidermal cells to promote migration and may be one mechanism by which LPSp promotes wound healing.

Applications of mesenchymal stem cell-exosome components in wound infection healing: new insights

The healing process at a wound is made up of many types of cells, growth factors, the extracellular matrix, nerves and blood vessels all interacting with each other in complex and changing ways. Microbial colonization and proliferation are possible at the place of injury, which makes infection more likely. Because of this, any cut has a chance of getting an infection. Researchers have found that wound infections make patients more upset and cost the healthcare system a lot of money. Surgical site infections happen a lot to people who have recently had surgery. This study shows that such surgical infection is linked to a high rate of illness and death. This is shown by the fact that 25% of patients get serious sepsis and need to be transferred to an intensive care unit. In both animal models and people, mesenchymal stem cells (MSCs) play an active role in all stages of wound healing and have positive effects. Exosomes are one of the main things MSCs release. They have effects that are similar to those of the parent MSCs. Various effector proteins, messenger RNA and microRNAs can be transported by extracellular vesicles to control the activity of target cells. This has a big impact on the healing process. These results suggest that using MSC-exosomes as a new type of cell-free therapy could be a better and safer option than whole cell therapy. This review is mostly about how to use parts of MSC-exosomes to help wound infections heal.

Postbiotics-peptidoglycan, lipoteichoic acid, exopolysaccharides, surface layer protein and pili proteins-Structure, activity in wounds and their delivery systems

Chronic wound healing is a pressing global public health concern. Abuse and drug resistance of antibiotics are the key problems in the treatment of chronic wounds at present. Postbiotics are a novel promising strategy. Previous studies have reported that postbiotics have a wide range of biological activities including antimicrobial, immunomodulatory, antioxidant and anti-inflammatory abilities. However, several aspects related to these postbiotic activities remain unexplored or poorly known. Therefore, this work aims to outline general aspects and emerging trends in the use of postbiotics for wound healing, such as the production, characterization, biological activities and delivery strategies of postbiotics. In this review, a comprehensive overview of the physiological activities and structures of postbiotic biomolecules that contribute to wound healing is provided, such as peptidoglycan, lipoteichoic acid, bacteriocins, exopolysaccharides, surface layer proteins, pili proteins, and secretory proteins (p40 and p75 proteins). Considering the presence of readily degradable components in postbiotics, potential natural polymer delivery materials and delivery systems are emphasized, followed by the potential applications and commercialization prospects of postbiotics. These findings suggest that the treatment of chronic wounds with postbiotic ingredients will help provide new insights into wound healing and better guidance for the development of postbiotic products.

Tissue resident cells differentiate S. aureus from S. epidermidis via IL-1β following barrier disruption in healthy human skin

The Staphylococcus sp. are a dominant part of the human skin microbiome and present across the body. Staphylococcus epidermidis is a ubiquitous skin commensal, while S. aureus is thought to colonize at least 30% of the population. S. aureus are not only colonizers but a leading cause of skin and soft tissue infections and a critical healthcare concern. To understand how healthy human skin may differentiate commensal bacteria, such as S. epidermidis, from the potential pathogen methicillin-resistant S. aureus (MRSA), we use ex vivo human skin models that allow us to study this host-bacterial interaction in the most clinically relevant environment. Our work highlights the role of the outer stratum corneum as a protective physical barrier against invasion by colonizing Staphylococci. We show how the structural cells of the skin can internalize and respond to different Staphylococci with increasing sensitivity. In intact human skin, a discriminatory IL-1β response was identified, while disruption of the protective stratum corneum triggered an increased and more diverse immune response. We identified and localized tissue resident Langerhans cells (LCs) as a potential source of IL-1β and go on to show a dose-dependent response of MUTZ-LCs to S. aureus but not S. epidermidis. This suggests an important role of LCs in sensing and discriminating between bacteria in healthy human skin, particularly in intact skin and provides a detailed snapshot of how human skin differentiates between friend and potential foe. With the rise in antibiotic resistance, understanding the innate immune response of healthy skin may help us find ways to enhance or manipulate these natural defenses to prevent invasive infection.

Postbiotic lactobacilli induce cutaneous antimicrobial response and restore the barrier to inhibit the intracellular invasion of Staphylococcus aureus in vitro and ex vivo

Intracellular pathogens including Staphylococcus aureus contribute to the non-healing phenotype of chronic wounds. Lactobacilli, well known as beneficial bacteria, are also reported to modulate the immune system, yet their role in cutaneous immunity remains largely unknown. We explored the therapeutic potential of bacteria-free postbiotics, bioactive lysates of lactobacilli, to reduce intracellular S. aureus colonization and promote healing. Fourteen postbiotics derived from various lactobacilli species were screened, and Latilactobacillus curvatus BGMK2-41 was selected for further analysis based on the most efficient ability to reduce intracellular infection by S. aureus diabetic foot ulcer clinical isolate and S. aureus USA300. Treatment of both infected keratinocytes in vitro and infected human skin ex vivo with BGMK2-41 postbiotic cleared S. aureus. Keratinocytes treated in vitro with BGMK2-41 upregulated expression of antimicrobial response genes, of which DEFB4, ANG, and RNASE7 were also found upregulated in treated ex vivo human skin together with CAMP exclusively upregulated ex vivo. Furthermore, BGMK2-41 postbiotic treatment has a multifaceted impact on the wound healing process. Treatment of keratinocytes stimulated cell migration and the expression of tight junction proteins, while in ex vivo human skin BGMK2-41 increased expression of anti-inflammatory cytokine IL-10, promoted re-epithelialization, and restored the epidermal barrier via upregulation of tight junction proteins. Together, this provides a potential therapeutic approach for persistent intracellular S. aureus infections.

Vitis vinifera L. Leaf Extract, a Microbiota Green Ally against Infectious and Inflammatory Skin and Scalp Diseases: An In-Depth Update

The skin microbiota, with its millions of bacteria, fungi, and viruses, plays a key role in balancing the health of the skin and scalp. Its continuous exposure to potentially harmful stressors can lead to abnormalities such as local dysbiosis, altered barrier function, pathobiont overabundance, and infections often sustained by multidrug-resistant bacteria. These factors contribute to skin impairment, deregulation of immune response, and chronic inflammation, with local and systemic consequences. In this scenario, according to the needs of the bio-circular-green economy model, novel harmless strategies, both for regulating the diverse epidermal infectious and inflammatory processes and for preserving or restoring the host skin eubiosis and barrier selectivity, are requested. Vitis vinifera L. leaves and their derived extracts are rich in plant secondary metabolites, such as polyphenols, with antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory properties that can be further exploited through microbe-driven fermentation processes. On this premise, this literature review aims to provide an informative summary of the most updated evidence on their interactions with skin commensals and pathogens and on their ability to manage inflammatory conditions and restore microbial biodiversity. The emerging research showcases the potential novel beneficial ingredients for addressing various skincare concerns and advancing the cosmeceutics field as well.

Development and characterization of an emulgel based on a snail slime useful for dermatological applications

Snail slime is an interesting material for effective dermatological use (e.g. wounds). Its properties are stricly connected to the origin. In this paper a snail slime, deriving from the species Helix aspersa Muller and obtained from a company, was deeply characterized and then properly formulated. The slime, obtained by Donatella Veroni method, was firstly submitted to NMR analysis in order to evaluate the chemical composition. The main molecules found are glycolate and allantoin, well known for their activities in wound healing promotion. In vitro experiments performed on keratinocytes, revealed the snail slime ability to promote cellular well-being. Moreover, the microbiological analysis showed high activity against many strains involved in wounds infections such as gram+ (e.g. S. aureus, S. pyogenes), gram- (e.g. P. aeruginosa, E. coli) and the yeast C. albicans. The effect on skin elasticity was evaluated as well by the instrument Cutometer® dualMPA580. The snail slime was then formulated as hydrophilic gel, using a combination of corn starch and sodium hyaluronate as polymers, then used as external water phase of an O/W emulgel. The formulation is physically stable and easily spreadable and demonstrated antimicrobial activity as observed for slime alone, suggesting its suitability to be used for wound treatment.

Commensal microbiome dysbiosis elicits interleukin-8 signaling to drive fibrotic skin disease

Wound healing is an intensely studied topic involved in many relevant pathophysiological processes, including fibrosis. Despite the large interest in fibrosis, the network that is related to commensal microbiota and skin fibrosis remains mysterious. Here, we pay attention to keloid, a classical yet intractable skin fibrotic disease to establish the association between commensal microbiota to scaring tissue. Our histological data reveal the presence of microbiota in the keloids. 16S rRNA sequencing characterizes microbial composition and divergence between the pathological and normal skin tissues. Moreover, the data show elevation of interleukin-8 (IL-8) in both the circulation and keloid tissue, which elicited the collagen accumulation and migratory program of dermal fibroblasts via CXCR1/2 receptor. Our research provides insights into the pathology of human fibrotic diseases, advocating commensal bacteria and IL-8 signaling as useful targets in future interventions of recurrent keloid disease.

Alcaligenes faecalis corrects aberrant matrix metalloproteinase expression to promote reepithelialization of diabetic wounds

Chronic wounds are a common and costly complication of diabetes, where multifactorial defects contribute to dysregulated skin repair, inflammation, tissue damage, and infection. We previously showed that aspects of the diabetic foot ulcer microbiota were correlated with poor healing outcomes, but many microbial species recovered remain uninvestigated with respect to wound healing. Here, we focused on Alcaligenes faecalis, a Gram-negative bacterium that is frequently recovered from chronic wounds but rarely causes infection. Treatment of diabetic wounds with A. faecalis accelerated healing during early stages. We investigated the underlying mechanisms and found that A. faecalis treatment promotes reepithelialization of diabetic keratinocytes, a process that is necessary for healing but deficient in chronic wounds. Overexpression of matrix metalloproteinases in diabetes contributes to failed epithelialization, and we found that A. faecalis treatment balances this overexpression to allow proper healing. This work uncovers a mechanism of bacterial-driven wound repair and provides a foundation for the development of microbiota-based wound interventions.

Carbon source competition within the wound microenvironment can significantly influence infection progression

It is becoming increasingly apparent that commensal skin bacteria have an important role in wound healing and infection progression. However, the precise mechanisms underpinning many of these probiotic interactions remain to be fully uncovered. In this work, we demonstrate that the common skin commensal Cutibacterium acnes can limit the pathogenicity of the prevalent wound pathogen Pseudomonas aeruginosa in vivo. We show that this impact on pathogenicity is independent of any effect on growth, but occurs through a significant downregulation of the Type Three Secretion System (T3SS), the primary toxin secretion system utilised by P. aeruginosa in eukaryotic infection. We also show a downregulation in glucose acquisition systems, a known regulator of the T3SS, suggesting that glucose availability in a wound can influence infection progression. C. acnes is well known as a glucose fermenting organism, and we demonstrate that topically supplementing a wound with glucose reverses the probiotic effects of C. acnes. This suggests that introducing carbon source competition within the wound microenvironment may be an effective way to prevent or limit wound infection.

The past, present and future of polymicrobial infection research: Modelling, eavesdropping, terraforming and other stories

Over the last two centuries, great advances have been made in microbiology as a discipline. Much of this progress has come about as a consequence of studying the growth and physiology of individual microbial species in well-defined laboratory media; so-called "axenic growth". However, in the real world, microbes rarely live in such "splendid isolation" (to paraphrase Foster) and more often-than-not, share the niche with a plethora of co-habitants. The resulting interactions between species (and even between kingdoms) are only very poorly understood, both on a theoretical and experimental level. Nevertheless, the last few years have seen significant progress, and in this review, we assess the importance of polymicrobial infections, and show how improved experimental traction is advancing our understanding of these. A particular focus is on developments that are allowing us to capture the key features of polymicrobial infection scenarios, especially as those associated with the human airways (both healthy and diseased).

Direct metagenomics investigation of non-surgical hard-to-heal wounds: a review

BACKGROUND

Non-surgical chronic wounds, including diabetes-related foot diseases (DRFD), pressure injuries (PIs) and venous leg ulcers (VLU), are common hard-to-heal wounds. Wound evolution partly depends on microbial colonisation or infection, which is often confused by clinicians, thereby hampering proper management. Current routine microbiology investigation of these wounds is based on in vitro culture, focusing only on a limited panel of the most frequently isolated bacteria, leaving a large part of the wound microbiome undocumented.

METHODS

A literature search was conducted on original studies published through October 2022 reporting metagenomic next generation sequencing (mNGS) of chronic wound samples. Studies were eligible for inclusion if they applied 16 S rRNA metagenomics or shotgun metagenomics for microbiome analysis or diagnosis. Case reports, prospective, or retrospective studies were included. However, review articles, animal studies, in vitro model optimisation, benchmarking, treatment optimisation studies, and non-clinical studies were excluded. Articles were identified in PubMed, Google Scholar, Web of Science, Microsoft Academic, Crossref and Semantic Scholar databases.

RESULTS

Of the 3,202 articles found in the initial search, 2,336 articles were removed after deduplication and 834 articles following title and abstract screening. A further 14 were removed after full text reading, with 18 articles finally included. Data were provided for 3,628 patients, including 1,535 DRFDs, 956 VLUs, and 791 PIs, with 164 microbial genera and 116 species identified using mNGS approaches. A high microbial diversity was observed depending on the geographical location and wound evolution. Clinically infected wounds were the most diverse, possibly due to a widespread colonisation by pathogenic bacteria from body and environmental microbiota. mNGS data identified the presence of virus (EBV) and fungi (Candida and Aspergillus species), as well as Staphylococcus and Pseudomonas bacteriophages.

CONCLUSION

This study highlighted the benefit of mNGS for time-effective pathogen genome detection. Despite the majority of the included studies investigating only 16 S rDNA, ignoring a part of viral, fungal and parasite colonisation, mNGS detected a large number of bacteria through the included studies. Such technology could be implemented in routine microbiology for hard-to-heal wound microbiota investigation and post-treatment wound colonisation surveillance.

Highly active probiotic hydrogels matrixed on bacterial EPS accelerate wound healing via maintaining stable skin microbiota and reducing inflammation

Skin microbiota plays an important role in wound healing, but skin injuries are highly susceptible to wound infections, leading to disruption of the skin microbiota. However, conventional antibacterial hydrogels eliminate both probiotics and pathogenic bacteria, disrupting the balance of the skin microbiota. Therefore, it is important to develop a wound dressing that can fend off foreign pathogenic bacteria while preserving skin microbiota stability. Inspired by live bacteria therapy, we designed a probiotic hydrogel (HAEPS@L.sei gel) with high viability for promoting wound healing. Lactobacillus paracasei TYM202 encapsulated in the hydrogel has the activity of promoting wound healing, and the hydrogel matrix EPS-M76 has the prebiotic activity that promotes the proliferation and metabolism of Lactobacillus paracasei TYM202. During the wound healing process, HAEPS@L.sei gel releases lactic acid and acetic acid to resist the growth of pathogenic bacteria while maintaining Firmicutes and Proteobacteria balance at the phylum level, thus preserving skin microbiota stability. Our results showed that live probiotic hydrogels reduce the incidence of inflammation during wound healing while promoting angiogenesis and increasing collagen deposition. This study provides new ideas for developing wound dressings predicated on live bacterial hydrogels.

Stephanoascus ciferrii Complex: The Current State of Infections and Drug Resistance in Humans

In recent years, the incidence of fungal infections in humans has increased dramatically, accompanied by an expansion in the number of species implicated as etiological agents, especially environmental fungi never involved before in human infection. Among fungal pathogens, Candida species are the most common opportunistic fungi that can cause local and systemic infections, especially in immunocompromised individuals. Candida albicans (C. albicans) is the most common causative agent of mucosal and healthcare-associated systemic infections. However, during recent decades, there has been a worrying increase in the number of emerging multi-drug-resistant non-albicans Candida (NAC) species, i.e., C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, C. auris, and C. ciferrii. In particular, Candida ciferrii, also known as Stephanoascus ciferrii or Trichomonascus ciferrii, is a heterothallic ascomycete yeast-like fungus that has received attention in recent decades as a cause of local and systemic fungal diseases. Today, the new definition of the S. ciferrii complex, which consists of S. ciferrii, Candida allociferrii, and Candida mucifera, was proposed after sequencing the 18S rRNA gene. Currently, the S. ciferrii complex is mostly associated with non-severe ear and eye infections, although a few cases of severe candidemia have been reported in immunocompromised individuals. Low susceptibility to currently available antifungal drugs is a rising concern, especially in NAC species. In this regard, a high rate of resistance to azoles and more recently also to echinocandins has emerged in the S. ciferrii complex. This review focuses on epidemiological, biological, and clinical aspects of the S. ciferrii complex, including its pathogenicity and drug resistance.

Advancements in wound healing: integrating biomolecules, drug delivery carriers, and targeted therapeutics for enhanced tissue repair

Wound healing, a critical biological process vital for tissue restoration, has spurred a global market exceeding $15 billion for wound care products and $12 billion for scar treatment. Chronic wounds lead to delayed or impaired wound healing. Natural bioactive compounds, prized for minimal side effects, stand out as promising candidates for effective wound healing. In response, researchers are turning to nanotechnology, employing the encapsulation of these agents into drug delivery carriers. Drug delivery system will play a crucial role in enabling targeted delivery of therapeutic agents to promote tissue regeneration and address underlying issues such as inflammation, infection, and impaired angiogenesis in chronic wound healing. Drug delivery carriers offer distinct advantages, exhibiting a substantial ratio of surface area to volume and altered physical and chemical properties. These carriers facilitate sustained and controlled release, proving particularly advantageous for the extended process of wound healing, that typically comprise a diverse range of components, integrating both natural and synthetic polymers. Additionally, they often incorporate bioactive molecules. Despite their properties, including poor solubility, rapid degradation, and limited bioavailability, various natural bioactive agents face challenges in clinical applications. With a global research, emphasis on harnessing nanomaterial for wound healing application, this research overview engages advancing drug delivery technologies to augment the effectiveness of tissue regeneration using bioactive molecules. Recent progress in drug delivery has poised to enhance the therapeutic efficacy of natural compounds in wound healing applications.

Trap & kill: a neutrophil-extracellular-trap mimic nanoparticle for anti-bacterial therapy

Fenton chemistry-mediated antimicrobials have demonstrated great promise in antibacterial therapy. However, the short life span and diffusion distance of hydroxyl radicals dampen the therapeutic efficiency of these antimicrobials. Herein, inspired by the neutrophil extracellular trap (NET), in which bacteria are trapped and agglutinated via electronic interactions and killed by reactive oxygen species, we fabricated a NET-mimic nanoparticle to suppress bacterial infection in a "trap & kill" manner. Specifically, this NET-mimic nanoparticle was synthesized via polymerization of ferrocene monomers followed by quaternization with a mannose derivative. Similar to the NET, the NET-mimic nanoparticles trap bacteria through electronic and sugar-lectin interactions between their mannose moieties and the lectins of bacteria, forming bacterial agglutinations. Therefore, they confine the spread of the bacteria and restrict the bacterial cells to the destruction range of hydroxyl radicals. Meanwhile, the ferrocene component of the nanoparticle catalyzes the production of highly toxic hydroxyl radicals at the H2O2 rich infection foci and effectively eradicates the agglutinated bacteria. In a mouse model of an antimicrobial-resistant bacteria-infected wound, the NET-mimic nanoparticles displayed potent antibacterial activity and accelerated wound healing.

Lactobacillus Plantarum Promotes Wound Healing by Inhibiting the NLRP3 Inflammasome and Pyroptosis Activation in Diabetic Foot Wounds

Objective

Diabetic foot ulcer (DFU) impairs the quality of life of diabetic patients and overburdens healthcare systems and society. It is crucial to comprehend the pathophysiology of DFU and develop effective treatment strategies. The aim of this study was to to evaluate the therapeutic potential of Lactobacillus Plantarum (LP) on wound healing in DFU and to explore the underlying mechanisms.

Methods

To investigate the effects of LP on wound healing, human umbilical vein endothelial cells (HUVECs) were treated with advanced glycation end products (AGEs) and used to assess cell viability, migration, and pyroptosis using CCK-8, cell scratch, and flow cytometry. The levels of IL-1β and IL-18 were measured by ELISA. The expression of NLRP3, caspase-1 p20, and GSDMD-N was detected by Western blot. Additionally, NLRP3 inhibitor MCC950 was used to treat a diabetic rat model established by streptozotocin (STZ). Pearson correlation analysis was performed to analyze the relationship between LP and NLRP3, IL-1β, IL-18 in ulcer tissue.

Results

Our data mechanistically demonstrate that AGEs activate the NLRP3/Caspase-1/GSDMD pathway, leading to an increase in the levels of IL-1β and IL-18 and ultimately promoting cell pyroptosis. Furthermore, we identified that LP inhibits the effects of AGEs by downregulating NLRP3 inflammasome activity. LP facilitated wound healing in diabetic rats and resulted in decreased protein levels of NLRP3 and its downstream target caspase-1 p20. Finally, we observed a negative correlation between LP and NLRP3, IL-1β, IL-18 in diabetic foot skin tissue.

Conclusion

Our findings uncovered a novel role of LP in diabetic foot wound healing via regulation of the NLRP3 inflammasome, suggesting this link as a therapeutic target. In future research, it would be valuable to explore the signaling cascades involved in LP-mediated inhibition of NLRP3 inflammasome activation.

The role of the skin microbiome in wound healing

The efficient management of skin wounds for rapid and scarless healing represents a major clinical unmet need. Nonhealing skin wounds and undesired scar formation impair quality of life and result in high healthcare expenditure worldwide. The skin-colonizing microbiota contributes to maintaining an intact skin barrier in homeostasis, but it also participates in the pathogenesis of many skin disorders, including aberrant wound healing, in many respects. This review focuses on the composition of the skin microbiome in cutaneous wounds of different types (i.e. acute and chronic) and with different outcomes (i.e. nonhealing and hypertrophic scarring), mainly based on next-generation sequencing analyses; furthermore, we discuss the mechanistic insights into host-microbe and microbe-microbe interactions during wound healing. Finally, we highlight potential therapeutic strategies that target the skin microbiome to improve healing outcomes.