Response of Human Macrophages to Clinically Applied Wound Dressings Loaded With Silver

AXL/GAS6 signaling governs differentiation of tumor-associated macrophages in breast cancer

Most epithelial cancers are infiltrated by prognostically relevant myelomonocytic cells. Immunosuppressive tumor associated macrophages (TAMs) and their precursor monocytic-MDSCs have previously been associated with worse outcomes in human breast cancer (BCa), yet the mechanism of immunosuppressive TAMs-polarization from myelomonocytic precursors is not completely understood. In this study, we show that persuaded AXL/GAS6 pathway alters macrophage phenotype from HLA-DRhighCD206low CD163low classical phagocytic into HLA-DRlowCD206highCD163high immunosuppressive ones with accelerated BCa progression, and increased angiogenesis signature and invasion ability of cancer cells at tumor beds. Notably, both AXL and GAS6 expressions are upregulated in human invasive breast carcinoma, with maximum expression in triple negative histology type. Mechanistically, we demonstrate that AXL/GAS6 signaling drives immunosuppression by governing increased immunosuppressive IL10 production while dampening IL-1β expression within the tumor microenvironment (TME) of BCa. Further, AXL/GAS6 signaling promotes angiogenesis through the activation of PI3K/AKT and NF-κB signaling pathways. Our results unveil role of AXL/GAS6 axis in the differentiation of TAMs, which governs malignant growth, and suggest that therapies that uncouple AXL/GAS6 axis may exhibit therapeutic opportunity for otherwise undruggable Triple Negative Breast Cancer (TNBC) patients.

Exploring an Innovative Approach: Integrating Negative-Pressure Wound Therapy with Silver Nanoparticle Dressings in Skin Graft Procedures

BACKGROUND

Skin grafting is a helpful instrument in a plastic surgeon's arsenal. Several types of dressings were designed to facilitate the process of graft integration. Negative-pressure wound therapy is a proven dressing method, enhancing graft survival through several mechanisms: aspiration of secretions, stimulation of neoangiogenesis, and promotion of an anti-inflammatory environment. Silver nanoparticle dressings also bring multiple benefits by bearing an antimicrobial effect and providing a humid medium, which are favorable for epithelialization. The combination of NPWT (negative-pressure wound therapy) with AgNPs (silver nanoparticles) has not been widely studied.

MATERIALS AND METHODS

This study aimed to compare the outcomes of silver nanoparticle sheets with the combination of negative-pressure wound therapy and silver nanoparticle dressings. We conducted a comparative prospective study on 80 patients admitted to the Plastic Surgery Department of "Prof. Dr. Agrippa Ionescu" Emergency Clinical Hospital between 1st of January 2020 and 31st of December 2022. The study population was randomized to receive either silver nanoparticle dressings or negative-pressure wound therapy (NPWT) combined with silver nanoparticle dressings. Various parameters were monitored, including patient comorbidities and graft-related data such as defect etiology, graft integration, and graft size. Dressings were changed, and graft status was evaluated at 7, 10, and 14 days postoperatively. Additionally, baseline C-reactive protein (CRP) levels were measured before surgery and 7, 10, and 14 days postoperatively.

RESULTS

The study demonstrated an enhanced integration of skin grafts at all evaluation stages when employing NPWT combined with AgNPs, particularly evident 10 days post operation. Significant variations in graft integration were also observed based on factors such as diabetes, cardiovascular disease, graft size, or the origin of the grafted defect. Moreover, dynamic C-reactive protein monitoring showed a statistically significant decrease in CRP levels 10 days post operation among patients treated with NPWT in conjunction with silver dressing, consistent with the nearly complete integration of skin grafts at this evaluation threshold.

CONCLUSION

Several factors influence the postoperative evolution of split-skin grafts. Postoperative dressings target local factors to enhance graft integration further. Our research demonstrated that the innovative combination of NPWT-assisted dressings, complemented by a silver nanoparticle sheet, resulted in improved benefits for graft integration and the alleviation of systemic inflammation.

Current Advances in Wound Healing and Regenerative Medicine

Treating chronic wounds is a common and costly challenge worldwide. More advanced treatments are needed to improve wound healing and prevent severe complications such as infection and amputation. Like other medical fields, there have been advances in new technologies promoting wound healing potential. Regenerative medicine as a new method has aroused hope in treating chronic wounds. The technology improving wound healing includes using customizable matrices based on synthetic and natural polymers, different types of autologous and allogeneic cells at different differentiation phases, small molecules, peptides, and proteins as a growth factor, RNA interference, and gene therapy. In the last decade, various types of wound dressings have been designed. Emerging dressings include a variety of interactive/ bioactive dressings and tissue-engineering skin options. However, there is still no suitable and effective dressing to treat all chronic wounds. This article reviews different wounds and common treatments, advanced technologies and wound dressings, the advanced wound care market, and some interactive/bioactive wound dressings in the market.

Borrowing the Features of Biopolymers for Emerging Wound Healing Dressings: A Review

Wound dressing design is a dynamic and rapidly growing field of the medical wound-care market worldwide. Advances in technology have resulted in the development of a wide range of wound dressings that treat different types of wounds by targeting the four phases of healing. The ideal wound dressing should perform rapid healing; preserve the body’s water content; be oxygen permeable, non-adherent on the wound and hypoallergenic; and provide a barrier against external contaminants—at a reasonable cost and with minimal inconvenience to the patient. Therefore, choosing the best dressing should be based on what the wound needs and what the dressing does to achieve complete regeneration and restoration of the skin’s structure and function. Biopolymers, such as alginate (ALG), chitosan (Cs), collagen (Col), hyaluronic acid (HA) and silk fibroin (SF), are extensively used in wound management due to their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body. However, most of the formulations based on biopolymers still show various issues; thus, strategies to combine them with molecular biology approaches represent the future of wound healing. Therefore, this article provides an overview of biopolymers’ roles in wound physiology as a perspective on the development of a new generation of enhanced, naturally inspired, smart wound dressings based on blood products, stem cells and growth factors.

An agonistic monoclonal antibody targeting cMet attenuates inflammation and upregulates collagen synthesis and angiogenesis in Type 2 diabetic mouse wounds

BACKGROUND

Diabetic wounds account for 25%-50% of total diabetic healthcare costs annually, and present overall healing rates of less than 50%. Since delayed diabetic wound healing is associated with impaired fibroblast function, we hypothesize that tyrosine kinase Met (cMet) agonistic monoclonal antibody (mAb) will promote diabetic wound healing via stable activation of HGF/cMet signaling.

METHODS

Two 6 mm dorsal wounds were created in each mice (6-week-old, male BKS.Cg-Dock7m+/+Leprdb/J, n=5). After subcutaneous injections of agonist (20 mg/kg) at 0 and 72h, the wound sizes were measured at days 0, 1, 3, 6, and 10. Histological and immunohistochemical analyses were performed at day 10 (cMet, α-SMA, CD68, and TGF-β). In vitro cytotoxicity and migration tests with diabetic fibroblasts were performed with/without agonist treatment (1 or 10 nM). cMet pathway activation of fibroblasts was confirmed through p-p44/42MAPK, p-mTOR, p-cMet, and ROCK-1 expression.

RESULTS

cMet agonistic mAb-treated group showed 1.60-fold lower wound area (p=0.027), 1.54-fold higher collagen synthesis (p=0.001), and 1.79-fold lower inflammatory cell infiltration (p=0.032) than the saline-treated control. The agonist increased cMet (1.86-fold, p=0.029), α-SMA (1.20-fold, p=0.018), and VEGF (1.68-fold, p=0.029) expression but suppressed CD68 (1.25-fold, p=0.043), TFG-β (1.25-fold, p=0.022), and MMP-2 (2.59-fold, p=0.029) expression. In vitro agonist treatment (10 nM) of diabetic fibroblasts increased their migration by 8.98-fold (p=0.029) and activated HGF/cMet pathway.

CONCLUSIONS

cMet agonistic mAb treatment improved diabetic wound healing in mice and reduced wound-site inflammatory cell infiltration. These results need to be validated in large animals before piloting human trials.

Local immunomodulatory effects of intracanal medications in apical periodontitis

The immune system is an extremely complex biological network that plays a crucial role in the hemostasis of periapical tissue, pathogenesis of apical periodontitis (AP) as well as periapical tissue healing. The successful elimination of microbial infections remains a significant challenge, mostly due to the ever-growing development of antimicrobial-resistant pathogens. The bacterial endurance in the root canal system contributes to features ranging from altered post-treatment healing to exacerbation of chronic periradicular immune response, that compromise the outcome of endodontic treatment. A highly effective strategy for combating infectious diseases and the associated inflammation-mediated tissue damage is to modulate the host immune response in conjunction with antimicrobial therapy. There are several medications currently used in endodontic treatment, however, they suffer various levels of microbial resistance and do not deliver all the required characteristics to simultaneously address both intracanal bacteria and periapical inflammation. Interaction of antimicrobial agents with the immune system can impact its function, leading to immune-suppressive or immune-stimulatory effects. The group of non-conventional antimicrobial medications, such as antimicrobial peptides, propolis, and nanomaterials, are agents that provide strong antimicrobial effectiveness and concomitant immunomodulatory and/or reparative effect, without any host tissue damages. Herein, we provide an overview of local immune modulation in AP and a comprehensive review of the immunomodulatory effect of antimicrobials intracanal medications applied in endodontics with specific emphasis on the antimicrobial nanomaterial-based approaches that provide immunomodulatory potential for successful clinical deployment in endodontics.

Management of a Pelvic Abscess and Abdominal Fistula after Palliative Total Pelvic Exenteration with Intraoperative Radiotherapy in Recurrent Rectal Cancer Without NPWT: A Case Report

ABSTRACT

A 59-year-old man with recurrent rectal cancer and type 2 diabetes mellitus underwent palliative total pelvic exenteration and intraoperative radiotherapy. After surgery, he experienced a pelvic abscess and abdominal-perineal fistula. Profuse exudate contaminated the midline abdominal incision through the abdominal-perineal fistula and delayed healing. Because of a residual tumor and the high cost, negative-pressure wound therapy was not performed. After 76 days of local treatment that involved removing necrotic tissue, controlling inflammation with an antimicrobial silver dressing, absorbing and draining exudate with a hypertonic saline dressing, promoting granulation and preventing infection with a silver alginate dressing, and promoting re-epithelialization with recombinant human epidermal growth factor gel, the abdominal wound and abdominal-perineal fistula healed successfully.

Bioactive Agent-Loaded Electrospun Nanofiber Membranes for Accelerating Healing Process: A Review

Despite the advances that have been achieved in developing wound dressings to date, wound healing still remains a challenge in the healthcare system. None of the wound dressings currently used clinically can mimic all the properties of normal and healthy skin. Electrospinning has gained remarkable attention in wound healing applications because of its excellent ability to form nanostructures similar to natural extracellular matrix (ECM). Electrospun dressing accelerates the wound healing process by transferring drugs or active agents to the wound site sooner. This review provides a concise overview of the recent developments in bioactive electrospun dressings, which are effective in treating acute and chronic wounds and can successfully heal the wound. We also discuss bioactive agents used to incorporate electrospun wound dressings to improve their therapeutic potential in wound healing. In addition, here we present commercial dressings loaded with bioactive agents with a comparison between their features and capabilities. Furthermore, we discuss challenges and promises and offer suggestions for future research on bioactive agent-loaded nanofiber membranes to guide future researchers in designing more effective dressing for wound healing and skin regeneration.

Modifications of Wound Dressings with Bioactive Agents to Achieve Improved Pro-Healing Properties

The great variety of wounds and the lack of an effective universal treatment method has resulted in high demand for modern treatment strategies. Traditional approaches are often ineffective on a variety of chronic wounds, such as venous ulcers or the diabetic foot ulcer. There is strong evidence that naturally derived bioactive compounds have pro-healing properties, raising a great interest in their potential use for wound healing. Plant-derived compounds, such as curcumin and essential oils, are widely used to modify materials applied as wound dressings. Moreover, dressing materials are more often enriched with vitamins (e.g., L-ascorbic acid, tocopherol) and drugs (e.g., antibiotics, inhibitors of proteases) to improve the skin healing rate. Biomaterials loaded with the above-mentioned molecules show better biocompatibility and are basically characterized by better biological properties, ensuring faster tissue repair process. The main emphasis of the presented review is put on the novel findings concerning modern pro-healing wound dressings that have contributed to the development of regenerative medicine. The article briefly describes the synthesis and modifications of biomaterials with bioactive compounds (including curcumin, essential oils, vitamins) to improve their pro-healing properties. The paper also summarizes biological effects of the novel wound dressings on the enhancement of skin regeneration. The current review was prepared based on the scientific contributions in the PubMed database (supported with Google Scholar searching) over the past 5 years using relevant keywords. Scientific reports on the modification of biomaterials using curcumin, vitamins, and essential oils were mainly considered.

Ca-Zn-Ag Alginate Aerogels for Wound Healing Applications: Swelling Behavior in Simulated Human Body Fluids and Effect on Macrophages

Chronic non-healing wounds represent a substantial economic burden to healthcare systems and cause a considerable reduction in quality of life for those affected. Approximately 0.5-2% of the population in developed countries are projected to experience a chronic wound in their lifetime, necessitating further developments in the area of wound care materials. The use of aerogels for wound healing applications has increased due to their high exudate absorbency and ability to incorporate therapeutic substances, amongst them trace metals, to promote wound-healing. This study evaluates the swelling behavior of Ca-Zn-Ag-loaded alginate aerogels and their metal release upon incubation in human sweat or wound fluid substitutes. All aerogels show excellent liquid uptake from any of the formulas and high liquid holding capacities. Calcium is only marginally released into the swelling solvents, thus remaining as alginate bridging component aiding the absorption and fast transfer of liquids into the aerogel network. The zinc transfer quota is similar to those observed for common wound dressings in human and animal injury models. With respect to the immune regulatory function of zinc, cell culture studies show a high availability and anti-inflammatory activity of aerogel released Zn-species in RAW 264.7 macrophages. For silver, the balance between antibacterial effectiveness versus cytotoxicity remains a significant challenge for which the alginate aerogels need to be improved in the future. An increased knowledge of the transformations that alginate aerogels undergo in the course of the fabrication as well as during wound fluid exposure is necessary when aiming to create advanced, tissue-compatible aerogel products.