Inflammation in wound repair: molecular and cellular mechanisms

Recent advances in strategies to target the behavior of macrophages in wound healing

Chronic wounds and scar formation are widespread due to limited suitable remedies. The macrophage is a crucial regulator in wound healing, controlling the onset and termination of inflammation and regulating other processes related to wound healing. The current breakthroughs in developing new medications and drug delivery methods have enabled the accurate targeting of macrophages in oncology and rheumatic disease therapies through clinical trials. These successes have cleared the way to utilize drugs targeting macrophages in various disorders. This review thus summarizes macrophage involvement in normal and pathologic wound healing. It further details the targets available for macrophage intervention and therapeutic strategies for targeting the behavior of macrophages in tissue repair and regeneration.

Hyaluronic acid/alginate-based biomimetic hydrogel membranes for accelerated diabetic wound repair

The study aims to develop a new multifunctional biopolymer-based hydrogel membrane dressing by adopting a solvent casting method for the controlled release of cefotaxime sodium at the wound site. Sodium alginate enhances collagen production in the skin, which provides tensile strength to healing tissue. Moreover, the significance of extracellular molecules such as hyaluronic acid in the wound the healing cascade renders these biopolymers an essential ingredient for the fabrication of hydrogel membranes via physical crosslinking (hydrogen bonding). These membranes were further investigated in terms of their structure, and surface morphology, as well as cell viability analysis. A membrane with the most suitable characteristics was chosen as a candidate for cefotaxime sodium loading and in vivo analysis. Results show that the 3D porous nature of developed membranes allows optimum water vapor and oxygen transmission (>8.21 mg/mL) to divert excessive wound exudate away from the diabetic wound bed, MTT assay confirmed cell viability at more than 80%. In vivo results confirmed that the CTX-HA-Alg-PVA hydrogel group showed rapid wound healing with accelerated re-epithelization and a decreased inflammatory response. Conclusively, these findings indicate that CTX-HA-Alg-PVA hydrogel membranes exhibit a suitable niche for use as dressing membranes for healing of diabetic wounds.

The functions and clinical application potential of exosomes derived from mesenchymal stem cells on wound repair: a review of recent research advances

Wound repair is a complex problem for both clinical practitioners and scientific investigators. Conventional approaches to wound repair have been associated with several limitations, including prolonged treatment duration, high treatment expenses, and significant economic and psychological strain on patients. Consequently, there is a pressing demand for more efficacious and secure treatment modalities to enhance the existing treatment landscapes. In the field of wound repair, cell-free therapy, particularly the use of mesenchymal stem cell-derived exosomes (MSC-Exos), has made notable advancements in recent years. Exosomes, which are small lipid bilayer vesicles discharged by MSCs, harbor bioactive constituents such as proteins, lipids, microRNA (miRNA), and messenger RNA (mRNA). These constituents facilitate material transfer and information exchange between the cells, thereby regulating their biological functions. This article presents a comprehensive survey of the function and mechanisms of MSC-Exos in the context of wound healing, emphasizing their beneficial impact on each phase of the process, including the regulation of the immune response, inhibition of inflammation, promotion of angiogenesis, advancement of cell proliferation and migration, and reduction of scar formation.

Potential Broad-Spectrum Antimicrobial, Wound Healing, and Disinfectant Cationic Peptide Crafted from Snake Venom

Antimicrobial cationic peptides are intriguing and propitious antibiotics for the future, even against multidrug-resistant superbugs. Venoms serve as a source of cutting-edge therapeutics and innovative, unexplored medicines. In this study, a novel cationic peptide library consisting of seven sequences was designed and synthesized from the snake venom cathelicidin, batroxicidin (BatxC), with the inclusion of the FLPII motif at the N-terminus. SP1V3_1 demonstrated exceptional antibacterial effectiveness against Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae and destroyed the bacteria by depolarizing, rupturing, and permeabilizing their membranes, as evident from fluorescence assays, atomic force microscopy, and scanning electron microscopy. SP1V3_1 was observed to modulate the immune response in LPS-elicited U937 cells and exhibited good antibiofilm activity against MRSA and K. pneumoniae. The peptide promoted wound healing and disinfection in the murine model. The study demonstrated that SP1V3_1 is an exciting peptide lead and may be explored further for the development of better therapeutic peptides.

Anti-Inflammatory Effect of Meriania hexamera Sprague by Targeting Syk Kinase in NF-κB Signaling

Inflammation is a protective mechanism against harmful stimuli. There are two types of inflammation, acute and chronic, and severe diseases such as cardiovascular disease and cancer can be caused by chronic inflammation. Therefore, this research was conducted to discover new anti-inflammatory drugs. Meriania hexamera Sprague is a common herb in the Amazon region in South America. It is used as a traditional medical herb by natives, but no studies to date have investigated its anti-inflammatory activity. Using lipopolysaccharide (LPS), pam3CSK4 (Pam3), and poly(I:C), we studied the M. hexamera Sprague-Methanol Extract's (Mh-ME) in vitro anti-inflammatory functions. Using RAW264.7 cells, we detected the released nitric oxide (NO) and mRNA expression extent of inducible nitric oxide synthase (iNOS) with pro-inflammatory proteins like tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and iterleukin-1 beta (IL-1β). It was found that Mh-ME suppressed the inflammatory activities in a dose-dependent manner. In the luciferase assay, the nuclear factor kappa light chain enhancer of the activated B cells (NF-κB) pathway was inhibited by Mh-ME. Mh-ME especially acted as an inhibitor of Syk kinase according to the results from CETSA. We also confirmed that Mh-ME mitigates acute gastritis derived from HCl/EtOH in ICR mice, ameliorating the expression of IL-1β and tumor necrosis factor-alpha (TNF-α). In conclusion, Mh-ME is an herb with anti-inflammatory effects that targets Syk in the NF-κB pathway, suggesting that Mh-ME could be used as an anti-inflammatory herbal medicine.

Functional drug-delivery hydrogels for oral and maxillofacial wound healing

The repair process for oral and maxillofacial injuries involves hemostasis, inflammation, proliferation, and remodeling. Injury repair involves a variety of cells, including platelets, immune cells, fibroblasts, and various cytokines. Rapid and adequate healing of oral and maxillofacial trauma is a major concern to patients. Functional drug-delivery hydrogels play an active role in promoting wound healing and have shown unique advantages in wound dressings. Functional hydrogels promote wound healing through their adhesive, anti-inflammatory, antioxidant, antibacterial, hemostatic, angiogenic, and re-epithelialization-promoting properties, effectively sealing wounds and reducing inflammation. In addition, functional hydrogels can respond to changes in temperature, light, magnetic fields, pH, and reactive oxygen species to release drugs, enabling precise treatment. Furthermore, hydrogels can deliver various cargos that promote healing, including nucleic acids, cytokines, small-molecule drugs, stem cells, exosomes, and nanomaterials. Therefore, functional drug-delivery hydrogels have a positive impact on the healing of oral and maxillofacial injuries. This review describes the oral mucosal structure and healing process and summarizes the currently available responsive hydrogels used to promote wound healing.

Beyond Angiogenesis: The Multitasking Approach of the First PEGylated Vascular Endothelial Growth Factor (CdtVEGF) from Brazilian Rattlesnake Venom

A pioneering study regarding the isolation, biochemical evaluation, functional assays and first PEGylation report of a novel vascular endothelial growth factor from Crotalus durissus terrificus venom (CdtVEGF and PEG-CdtVEGF). CdtVEGF was isolated from crude venom using two different chromatographic steps, representing 2% of soluble venom proteins. Its primary sequence was determined using mass spectrometry analysis, and the molecule demonstrated no affinity to heparin. The Brazilian crotalid antivenom recognized CdtVEGF. Both native and PEGylated CdtVEGF were able to induce new vessel formation and migration, and to increase the metabolic activity of human umbilical endothelial vascular cells (HUVEC), resulting in better wound closure (~50% within 12 h) using the native form. CdtVEGF induced leukocyte recruitment to the peritoneal cavity in mice, with a predominance of neutrophil influx followed by lymphocytes, demonstrating the ability to activate the immune system. The molecule also induced a dose-dependent increase in vascular permeability, and PEG-CdtVEGF showed less in vivo inflammatory activity than CdtVEGF. By unraveling the intricate properties of minor components of snake venom like svVEGF, this study illuminates the indispensable significance of exploring these molecular tools to unveil physiological and pathological processes, elucidates the mechanisms of snakebite envenomings, and could possibly be used to design a therapeutic drug.

Polymeric biomaterials for wound healing

Skin indicates a person's state of health and is so important that it influences a person's emotional and psychological behavior. In this context, the effective treatment of wounds is a major concern, since several conventional wound healing materials have not been able to provide adequate healing, often leading to scar formation. Hence, the development of innovative biomaterials for wound healing is essential. Natural and synthetic polymers are used extensively for wound dressings and scaffold production. Both natural and synthetic polymers have beneficial properties and limitations, so they are often used in combination to overcome overcome their individual limitations. The use of different polymers in the production of biomaterials has proven to be a promising alternative for the treatment of wounds, as their capacity to accelerate the healing process has been demonstrated in many studies. Thus, this work focuses on describing several currently commercially available solutions used for the management of skin wounds, such as polymeric biomaterials for skin substitutes. New directions, strategies, and innovative technologies for the design of polymeric biomaterials are also addressed, providing solutions for deep burns, personalized care and faster healing.

Dasatinib Ointment Promotes Healing of Murine Excisional Skin Wound

Dasatinib, a tyrosine kinase inhibitor, has been shown to produce anti-inflammatory activity and impair vascular integrity in vivo, including during skin wound healing, potentially promoting the repair process. Given that dasatinib is a lipophilic small molecule capable of penetrating skin, topical dasatinib might provide benefits in wound healing. In the present study, we investigated the impact of dasatinib ointments in skin wound healing in mice. A full thickness excisional skin wound (4 mm diameter) was generated on the shaved dorsum of eight-week-old C57BL/6 mice. Dasatinib ointment (0.1 or 0.2% w/w) or ointment base was applied twice daily (every 12 h) for 10 days. Elizabethan collars were used to prevent animal licking. The wound size was monitored daily for 14 days. The results showed that dasatinib ointments, particularly 0.1% dasatinib, promoted a 16-23% reduction in wound size (p < 0.05) during day 2 to day 6 postinjury compared to controls. Immunohistochemistry analyses demonstrated a reduction in wound neutrophils (38% reduction, p = 0.04), macrophages (47% reduction, p = 0.005), and tumor necrosis factor-α levels (73% reduction, p < 0.01), together with an induction of vascular leakage-mediated fibrin(ogen) accumulation (2.5-fold increase, p < 0.01) in the wound during day 3 postinjury (an early phase of repair) in 0.1% dasatinib-treated mice relative to control mice. The anti-inflammatory and vascular hyperpermeability activities of dasatinib were associated with an enhanced healing process, including increased keratinocyte proliferation (1.8-fold increase in Ki67+ cells, p < 0.05) and augmented angiogenesis (1.7-fold increase in CD31+ area, p < 0.05), compared to the ointment base-treated group. Following treatment with 0.2% dasatinib ointment, minor wound bleeding and scab reformation were observed during the late phase, which contributed to delayed healing. In conclusion, our data suggest that dasatinib ointment, mainly at 0.1%, promotes the repair process by reducing inflammation and producing a local and temporal vascular leakage, leading to an increase in fibrin(ogen) deposition, re-epithelialization, and angiogenesis. Therefore, topical dasatinib might be a potential novel candidate to facilitate skin wound healing.

Construction of a robust turn-on fluorescence NIR sensor for rapid detection and imaging of ONOO- in inflammatory models

Peroxynitrite (OONO^-) is closely related to the occurrence and development of health and inflammatory diseases. The physiological and pathological results of OONO^- are related to the local concentration of ONOO^-. Therefore, to develop of a simple, rapid and reliable OONO^- detection tool is badly needed. In this work, we developed a small-molecule near-infrared (NIR) turn-on fluorescence sensor (NN1), harnessing a well-known response group phenylboronic acid response toward OONO^-. It shows high detection sensitivity and yields a ratio (I₆₅₈/I₀) fluorescence enhancement (∼280-fold). In addition, NN1 can be effectively used to detect endogenous and exogenous ONOO^- in living inflammatory cells. Notably, NN1 can be applied to OONO^- imaging analysis in drug-induced inflammatory mice model with satisfactory results. Therefore, NN1 is a robust molecular biological tool, which has a good prospect in the study of ONOO^- and the occurrence and development of inflammatory diseases.

Wound Healing Effect of Supercritical Carbon Dioxide Datura metel L. Leaves Extracts: An In Vitro Study of Anti-Inflammation, Cell Migration, MMP-2 Inhibition, and the Modulation of the Sonic Hedgehog Pathway in Human Fibroblasts

Datura metel L. (thorn apple) has been used in Thai folk wisdom for wound care. In this study, we chose supercritical carbon dioxide extraction (scCO₂) to develop crude extraction from the leaves of the thorn apple. The phytochemical profiles were observed using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). The biological activities of D. metel were performed through antioxidant assays, anti-inflammation based on the Griess reaction, the migration assay, the expression of matrix metalloproteinase-2 (MMP-2), and regulatory genes in fibroblasts. Dm1 and Dm2 extracts were obtained from scCO₂ procedures at different pressures of 300 and 500 bar, respectively. Bioactive compounds, including farnesyl acetone, schisanhenol B, and loliolide, were identified in both extracts. The antioxidant properties of both D. metel extracts were comparable to those of l-ascorbic acid in hydrogen peroxide-induced fibroblasts with no significant difference. Additionally, Dm1 and Dm2 significantly inhibited the nitrite production levels of 1.23 ± 0.19 and 1.52 ± 0.05 μM, respectively, against the lipopolysaccharide-treated group (3.82 ± 0.39 μM). Interestingly, Dm1 obviously demonstrated the percentage of wound closure with 58.46 ± 7.61 and 82.62 ± 6.66% after 36 and 48 h of treatment, which were comparable to the commercial deproteinized dialysate from the calf blood extract. Moreover, both extracts were comparable to l-ascorbic acid treatment in their ability to suppress the expression of MMP-2: an enzyme that breaks down collagen. The gene expressions of SHH, SMO, and GLI1 that control the sonic hedgehog pathway were also clearly upregulated by Dm1. Consequently, the scCO₂ technique could be applied in D. metel extraction and contribute to potentially effective wound closure.

Control of the post-infarct immune microenvironment through biotherapeutic and biomaterial-based approaches

Ischemic heart failure (IHF) is a leading cause of morbidity and mortality worldwide, for which heart transplantation remains the only definitive treatment. IHF manifests from myocardial infarction (MI) that initiates tissue remodeling processes, mediated by mechanical changes in the tissue (loss of contractility, softening of the myocardium) that are interdependent with cellular mechanisms (cardiomyocyte death, inflammatory response). The early remodeling phase is characterized by robust inflammation that is necessary for tissue debridement and the initiation of repair processes. While later transition toward an immunoregenerative function is desirable, functional reorientation from an inflammatory to reparatory environment is often lacking, trapping the heart in a chronically inflamed state that perpetuates cardiomyocyte death, ventricular dilatation, excess fibrosis, and progressive IHF. Therapies can redirect the immune microenvironment, including biotherapeutic and biomaterial-based approaches. In this review, we outline these existing approaches, with a particular focus on the immunomodulatory effects of therapeutics (small molecule drugs, biomolecules, and cell or cell-derived products). Cardioprotective strategies, often focusing on immunosuppression, have shown promise in pre-clinical and clinical trials. However, immunoregenerative therapies are emerging that often benefit from exacerbating early inflammation. Biomaterials can be used to enhance these therapies as a result of their intrinsic immunomodulatory properties, parallel mechanisms of action (e.g., mechanical restraint), or by enabling cell or tissue-targeted delivery. We further discuss translatability and the continued progress of technologies and procedures that contribute to the bench-to-bedside development of these critically needed treatments.

Application of neurotransmitters and dental stem cells for pulp regeneration: A review

Introduction

Although there have been many studies on stem cells, few have investigated how neurotransmitters and stem cell proliferation interact to regenerate dental pulp. Dental pulp regeneration is an innovative procedure for reviving dental pulp, if feasible for the entire tooth. Upon tooth injury, activated platelets release serotonin and dopamine in bulk to mobilize dental pulp stem cells to mediate natural dental repair. This has induced research on the role of neurotransmitters in increasing the proliferation rate of stem cells. This review also covers prospective future treatments for dental pulp regeneration.

Methods

A literature search was performed via PubMed and ScienceDirect from 2001 to 2022, using the keywords "neurotransmitter," "stem cell," "tooth regeneration," "tooth repair," "regenerative dentistry," and "dental pulp." Different inclusion/exclusion criteria were used, and the search was restricted to English articles.

Results

Nine publications reporting neurotransmitter interactions with stem cells for tooth and pulp regeneration were selected.

Conclusion

Neurotransmitters were found to interact with dental stem cells. Evidence pointing to neurotransmitters as a factor in the increased proliferation of stem cells was found. This review thus gives hope for tooth pulp regeneration and repair.

Polymer-Based Wound Dressings Loaded with Ginsenoside Rg3

The skin, the largest organ in the human body, mainly plays a protective role. Once damaged, it can lead to acute or chronic wounds. Wound healing involves a series of complex physiological processes that require ideal wound dressings to promote it. The current wound dressings have characteristics such as high porosity and moderate water vapor permeability, but they are limited in antibacterial properties and cannot protect wounds from microbial infections, which can delay wound healing. In addition, several dressings contain antibiotics, which may have bad impacts on patients. Natural active substances have good biocompatibility; for example, ginsenoside Rg3 has anti-inflammatory, antibacterial, antioxidant, and other biological activities, which can effectively promote wound healing. Some researchers have developed various polymer wound dressings loaded with ginsenoside Rg3 that have good biocompatibility and can effectively promote wound healing and reduce scar formation. This article will focus on the application and mechanism of ginsenoside Rg3-loaded dressings in wounds.

Evaluation of primary wound healing and potential complications after perioperative infiltration with lidocaine without adrenaline in surgical incisions in dogs and cats

BACKGROUND

Pre-emptive local analgesia with the use of lidocaine is practised increasingly in veterinary medicine as part of applied multimodal analgesia, despite its controversial impact on wound healing. The purpose of this prospective, randomised, double-blinded, placebo-controlled clinical study was to evaluate if preoperative subcutaneous infiltration of lidocaine has a negative impact on primary wound healing of surgical incisions. Fifty-two companion animals (3 cats and 49 dogs) were enrolled in the study. The inclusion criteria were as follows: American Society of Anaesthesiologists (ASA) score I or II, a minimum body weight of 5 kg, and a planned incisional length of at least 4 cm. Surgical incisions were infiltrated subcutaneously with lidocaine without adrenaline or NaCl (placebo). Follow-up questionnaires for owners and veterinarians and thermography of the surgical wound were used to assess wound healing. Antimicrobial use was documented.

RESULTS

There was no significant difference in either the total score or the individual assessment points between the treatment and the placebo group on the owner or the veterinary questionnaires in regard to primary wound healing (P > 0.05 for all comparisons). No significant difference was found between the thermography results of the treatment and placebo group (P = 0.78), and there was no significant correlation between the total score from the veterinary protocol and thermography results (Spearman's correlation coefficient - 0.10, P = 0.51). Surgical site infections developed in 5/53 (9.4%) surgeries and its occurrence varied significantly between the treatment and the placebo group as all cases of infection were in the placebo group (P = 0.05).

CONCLUSION

The results of this study indicate that lidocaine used as a local anaesthetic did not affect wound healing in patients with ASA scores I-II. The results suggest that lidocaine infiltration in surgical incisions can be safely used to reduce pain.

Investigating the active chemical constituents and pharmacology of Nanocnide lobata in the treatment of burn and scald injuries

OBJECTIVE

To identify the most effective fraction of Nanocnide lobata in the treatment of burn and scald injuries and determine its bioactive constituents.

METHODS

Chemical identification methods were used to analyze solutions extracted from Nanocnide lobata using petroleum ether, ethyl acetate, n-butanol using a variety of color reactions. The chemical constituents of the extracts were identified by ultra-performance liquid chromatography (UPLC)-mass spectrometry (MS). A total of 60 female mice were randomly divided into the following 6 groups: the petroleum ether extract-treated group; the ethyl acetate extract-treated group; the n-butanol extract-treated group; the model group; the control group; and the positive drug group. The burn/scald model was established using Stevenson's method. At 24 hours after modeling, 0.1 g of the corresponding ointment was evenly applied to the wound in each group. Mice in the model group did not undergo treatment, while those in the control group received 0.1 g of Vaseline. Wound characteristics, including color, secretions, hardness, and swelling, were observed and recorded. Photos were taken and the wound area calculated on the 1st, 5th, 8th, 12th, 15th, 18th and 21st days. Hematoxylin-eosin (HE) staining was utilized to observe the wound tissue of mice on the 7th, 14th, and 21st days. An enzyme-linked immunosorbent assay (ELISA) kit was used to measure the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-10, vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β1.

RESULTS

The chemical constituents of Nanocnide lobata mainly include volatile oils, coumarins, and lactones. UPLC-MS analysis revealed 39 main compounds in the Nanocnide lobata extract. Among them, ferulic acid, kaempferitrin, caffeic acid, and salicylic acid have been confirmed to exhibit anti-inflammatory and antioxidant activity related to the treatment of burns and scalds. HE staining revealed a gradual decrease in the number of inflammatory cells and healing of the wounds with increasing time after Nanocnide lobata extract administration. Compared with the model group, the petroleum ether extract-treated group showed significant differences in the levels of TNF-α (161.67±4.93, 106.33±3.21, 77.67±4.04 pg/mL) and IL-10 (291.77±4.93, 185.09±9.54, 141.33±1.53 pg/mL) on the 7th, 14th, and 21st days; a significant difference in the content of TGF-β1 (75.68±3.06 pg/mL) on the 21st day; and a significant difference in the level of VEGF (266.67±4.73, 311.33±10.50 pg/mL) on the 7th and 14th days respectively.

CONCLUSION

Petroleum ether Nanocnide lobata extract and the volatile oil compounds of Nanocnide lobata might be effective drugs in the treatment of burn and scald injuries, as they exhibited a protective effect on burns and scalds by reducing the expression of TNF-α, IL-10 and TGF-β1 and increasing the expression of VEGF. In addition, these compounds may also exert pharmacological effects that promote wound tissue repair, accelerate wound healing, and reduce scar tissue proliferation, inflammation and pain.

3D-printed placental-derived bioinks for skin tissue regeneration with improved angiogenesis and wound healing properties

Extracellular matrix (ECM)-based bioinks has attracted much attention in recent years for 3D printing of native-like tissue constructs. Due to organ unavailability, human placental ECM can be an alternative source for the construction of 3D print composite scaffolds for the treatment of deep wounds. In this study, we use different concentrations (1.5%, 3% and 5%w/v) of ECM derived from the placenta, sodium-alginate and gelatin to prepare a printable bioink biomimicking natural skin. The printed hydrogels' morphology, physical structure, mechanical behavior, biocompatibility, and angiogenic property are investigated. The optimized ECM (5%w/v) 3D printed scaffold is applied on full-thickness wounds created in a mouse model. Due to their unique native-like structure, the ECM-based scaffolds provide a non-cytotoxic microenvironment for cell adhesion, infiltration, angiogenesis, and proliferation. In contrast, they do not show any sign of immune response to the host. Notably, the biodegradation, swelling rate, mechanical property, cell adhesion and angiogenesis properties increase with the increase of ECM concentrations in the construct. The ECM 3D printed scaffold implanted into deep wounds increases granulation tissue formation, angiogenesis, and re-epithelialization due to the presence of ECM components in the construct, when compared with printed scaffold with no ECM and no treatment wound. Overall, our findings demonstrate that the 5% ECM 3D scaffold supports the best deep wound regeneration in vivo, produces a skin replacement with a cellular structure comparable to native skin.

Peptide Supramolecular Hydrogels with Sustained Release Ability for Combating Multidrug-Resistant Bacteria

Chronic wound infection caused by multidrug-resistant bacteria is a major threat globally, leading to high mortality rates and a considerable economic burden. To address it, an innovative supramolecular nanofiber hydrogel (Hydrogel-RL) harboring antimicrobial peptides was developed based on the novel arginine end-tagging peptide (Pep 6) from our recent study, triggering cross-linking. In vitro results demonstrated that Hydrogel-RL can sustain the release of Pep 6 up to 120 h profiles, which is biocompatible and exhibits superior activity for methicillin-resistant Staphylococcus aureus (MRSA) biofilm inhibition and elimination. A single treatment of supramolecular Hydrogel-RL on an MRSA skin infection model revealed formidable antimicrobial activity and therapeutic effects in vivo. In the chronic wound infection model, Hydrogel-RL promoted mouse skin cell proliferation, reduced inflammation, accelerated re-epithelialization, and regulated muscle and collagen fiber formation, rapidly healing full-thickness skin wounds. To show its vehicle property for wound infection combined therapy, etamsylate, an antihemorrhagic drug, was loaded into the porous network of Hydrogel-RL, which demonstrated improved hemostatic activity. Collectively, Hydrogel-RL is a promising clinical candidate agent for functional supramolecular biomaterials designed for combating multidrug-resistant bacteria and rescuing stalled healing in chronic wound infections.

Diabetic macrophage small extracellular vesicles-associated miR-503/IGF1R axis regulates endothelial cell function and affects wound healing

Diabetic foot ulcer (DFU) is a break in the skin of the foot caused by diabetes. It is one of the most serious and debilitating complications of diabetes. The previous study suggested that dominant M1 polarization during DFU could be the leading reason behind impaired wound healing. This study concluded that macrophage M1 polarization predominates in DFU skin tissue. iNOS was increased in HG-induced M1-polarized macrophages; conversely, Arg-1 was decreased. Macrophage pellets after HG stimulation can impair endothelial cell (EC) function by inhibiting cell viability, tube formation and cell migration, indicating M1 macrophage-derived small extracellular vesicles (sEVs) -mediated HUVEC dysfunction. sEVs miR-503 was significantly upregulated in response to HG stimulation, but inhibition of miR-503 in HG-stimulated macrophages attenuated M1 macrophage-induced HUVEC dysfunction. ACO1 interacted with miR-503 and mediated the miR-503 package into sEVs. Under HG stimulation, sEVs miR-503 taken in by HUVECs targeted IGF1R in HUVECs and inhibited IGF1R expression. In HUVECs, miR-503 inhibition improved HG-caused HUVEC dysfunction, whereas IGF1R knockdown aggravated HUVEC dysfunction; IGF1R knockdown partially attenuated miR-503 inhibition effects on HUVECs. In the skin wound model in control or STZ-induced diabetic mice, miR-503-inhibited sEVs improved, whereas IGF1R knockdown further hindered wound healing. Therefore, it can be inferred from the results that the M1 macrophage-derived sEVs miR-503 targets IGF1R in HUVECs, inhibits IGF1R expression, leads to HUVEC dysfunction, and impedes wound healing in diabetic patients, while packaging miR-503 as an M1 macrophage-derived sEVs may be mediated by ACO1.

Antioxidant Efficacy of Green-Synthesized Silver Nanoparticles Promotes Wound Healing in Mice

Developing an efficient and cost-effective wound-healing substance to treat wounds and regenerate skin is desperately needed in the current world. Antioxidant substances are gaining interest in wound healing, and green-synthesized silver nanoparticles have drawn considerable attention in biomedical applications due to their efficient, cost-effective, and non-toxic nature. The present study evaluated in vivo wound healing and antioxidant activities of silver nanoparticles from Azadirachta indica (AAgNPs) and Catharanthus roseus (CAgNPs) leaf extracts in BALB/c mice. We found rapid wound healing, higher collagen deposition, and increased DNA and protein content in AAgNPs- and CAgNPs (1% w/w)-treated wounds than in control and vehicle control wounds. Skin antioxidant enzyme activities (SOD, catalase, GPx, GR) were significantly (p < 0.05) increased after 11 days CAgNPs and AAgNPs treatment. Furthermore, the topical application of CAgNPs and AAgNPs tends to suppress lipid peroxidation in wounded skin samples. Histopathological images evidenced decreased scar width, epithelium restoration, fine collagen deposition, and fewer inflammatory cells in CAgNPs and AAgNPs applied wounds. In vitro, the free radical scavenging activity of CAgNPs and AAgNPs was demonstrated by DPPH and ABTS radical scavenging assays. Our findings suggest that silver nanoparticles prepared from C. roseus and A. indica leaf extracts increased antioxidant status and improved the wound-healing process in mice. Therefore, these silver nanoparticles could be potential natural antioxidants to treat wounds.

An Atmospheric Plasma Jet Induces Expression of Wound Healing Genes in Progressive Burn Wounds in a Comb Burn Rat Model: A Pilot Study

Burn-related injuries are devastating injuries with a high mortality rate that affect people of all ages worldwide. We assessed the effectiveness of plasma jet treatment in altering the expression of genes involved in wound healing in a prospective longitudinal observational animal study. Six male Sprague-Dawley rats weighing 350 g were used, and burn wounds were made by applying a preheated brass comb (100°C) to the back of the rats, resulting in four full-thickness burn wounds separated by three interspaces. A total of 18 burn wounds were induced on three rats. One side of the burn, on each rat received plasma treatment (plasma group), while the other side did not (control group). The interspaces were subjected to the plasma jet for 2 minutes per day until 7 days post-wounding. Plasma treatment significantly decreased the expression of proinflammatory cytokines. Furthermore, an increase in the expression of anti-inflammatory cytokines was observed in the plasma group. We showed that plasma jet treatment could improve burn wound healing by altering the expression of genes involved in the development of wound healing.

Resolvin D1 modulates periodontal ligament fibroblast function

BACKGROUND

The resolution of inflammation is an active process mediated by specialized lipid mediators called lipoxins and resolvins. Periodontal ligament fibroblasts (PDLFs) play a significant role in periodontal regeneration. The purpose of the current study was to determine the impact of resolvin D1 (RvD1) on human PDLF cell wound healing and proliferation, receptor expression (G-protein-coupled receptor 32 [GPR32] and formyl peptide receptor 2 [ALX/FPR2]), and cytokine expression and release.

METHODS

PDLFs were stimulated with interleukin-1β (IL-1β) (500 pg/ml) with and without RvD1 (100 nM). RvD1 receptor expression was determined by quantitative real-time polymerase chain reaction (qPCR), immunofluorescence microscopy, and fluorescence-activated cell sorting. Wound closure was measured by a scratch assay, and proliferation was determined by bromodeoxyuridine incorporation. Interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1, cyclooxygenase-2, matrix metalloproteinases-1, -2, and -3 (MMP-1, -2, and -3), tissue inhibitors of metalloproteinases-1 and -2 (TIMP-1 and -2), prostaglandin E2, and osteoprotegerin (OPG) gene expression and production were measured using qPCR and Western blotting, multiplex immunoassay, and enzyme-linked immunosorbent assay.

RESULTS

PDLF expressed GPR32 and ALX/FPR2. RvD1 reversed IL-1β-induced inhibition of wound healing and proliferation of PDLF. IL-1β also induced the production of proinflammatory cytokines and MMPs. This effect was reversed by RvD1. RvD1 reversed IL-1β-induced inhibition of TIMP-1, TIMP-2, and OPG.

CONCLUSION

The data suggested that RvD1 has a pro-wound healing, proliferative, and anti-inflammatory impact on the PDLF that favors periodontal regeneration.

An ERK-dependent molecular switch antagonizes fibrosis and promotes regeneration in spiny mice (Acomys)

Although most mammals heal injured tissues and organs with scarring, spiny mice (Acomys) naturally regenerate skin and complex musculoskeletal tissues. Now, the core signaling pathways driving mammalian tissue regeneration are poorly characterized. Here, we show that, while immediate extracellular signal-regulated kinase (ERK) activation is a shared feature of scarring (Mus) and regenerating (Acomys) injuries, ERK activity is only sustained at high levels during complex tissue regeneration. Following ERK inhibition, ear punch regeneration in Acomys shifted toward fibrotic repair. Using single-cell RNA sequencing, we identified ERK-responsive cell types. Loss- and gain-of-function experiments prompted us to uncover fibroblast growth factor and ErbB signaling as upstream ERK regulators of regeneration. The ectopic activation of ERK in scar-prone injuries induced a pro-regenerative response, including cell proliferation, extracellular matrix remodeling, and hair follicle neogenesis. Our data detail an important distinction in ERK activity between regenerating and poorly regenerating adult mammals and open avenues to redirect fibrotic repair toward regenerative healing.

A New Generation of IMiDs as Treatments for Neuroinflammatory and Neurodegenerative Disorders

The immunomodulatory imide drug (IMiD) class, which includes the founding drug member thalidomide and later generation drugs, lenalidomide and pomalidomide, has dramatically improved the clinical treatment of specific cancers, such as multiple myeloma, and it combines potent anticancer and anti-inflammatory actions. These actions, in large part, are mediated by IMiD binding to the human protein cereblon that forms a critical component of the E3 ubiquitin ligase complex. This complex ubiquitinates and thereby regulates the levels of multiple endogenous proteins. However, IMiD-cereblon binding modifies cereblon's normal targeted protein degradation towards a new set of neosubstrates that underlies the favorable pharmacological action of classical IMiDs, but also their adverse actions-in particular, their teratogenicity. The ability of classical IMiDs to reduce the synthesis of key proinflammatory cytokines, especially TNF-α levels, makes them potentially valuable to reposition as drugs to mitigate inflammatory-associated conditions and, particularly, neurological disorders driven by an excessive neuroinflammatory element, as occurs in traumatic brain injury, Alzheimer's and Parkinson's diseases, and ischemic stroke. The teratogenic and anticancer actions of classical IMiDs are substantial liabilities for effective drugs in these disorders and can theoretically be dialed out of the drug class. We review a select series of novel IMiDs designed to avoid binding with human cereblon and/or evade degradation of downstream neosubstrates considered to underpin the adverse actions of thalidomide-like drugs. These novel non-classical IMiDs hold potential as new medications for erythema nodosum leprosum (ENL), a painful inflammatory skin condition associated with Hansen's disease for which thalidomide remains widely used, and, in particular, as a new treatment strategy for neurodegenerative disorders in which neuroinflammation is a key component.

IL-4 and IL-13: Regulators and Effectors of Wound Repair

Type 2 immunity mediates protective responses to helminths and pathological responses to allergens, but it also has broad roles in the maintenance of tissue integrity, including wound repair. Type 2 cytokines are known to promote fibrosis, an overzealous repair response, but their contribution to healthy wound repair is less well understood. This review discusses the evidence that the canonical type 2 cytokines, IL-4 and IL-13, are integral to the tissue repair process through two main pathways. First, essential for the progression of effective tissue repair, IL-4 and IL-13 suppress the initial inflammatory response to injury. Second, these cytokines regulate how the extracellular matrix is modified, broken down, and rebuilt for effective repair. IL-4 and/or IL-13 amplifies multiple aspects of the tissue repair response, but many of these pathways are highly redundant and can be induced by other signals. Therefore, the exact contribution of IL-4Rα signaling remains difficult to unravel.

Potential Role of AGR2 for Mammalian Skin Wound Healing

The limited ability of mammals to regenerate has garnered significant attention, particularly in regard to skin wound healing (WH), which is a critical step for regeneration. In human adults, skin WH results in the formation of scars following injury or trauma, regardless of severity. This differs significantly from the scarless WH observed in the fetal skin of mammals or anamniotes. This review investigates the role of molecular players involved in scarless WH, which are lost or repressed in adult mammalian WH systems. Specifically, we analyze the physiological role of Anterior Gradient (AGR) family proteins at different stages of the WH regulatory network. AGR is activated in the regeneration of lower vertebrates at the stage of wound closure and, accordingly, is important for WH. Mammalian AGR2 is expressed during scarless WH in embryonic skin, while in adults, the activity of this gene is normally inhibited and is observed only in the mucous epithelium of the digestive tract, which is capable of full regeneration. The combination of AGR2 unique potencies in postnatal mammals makes it possible to consider it as a promising candidate for enhancing WH processes.

Advances in protein glycosylation and its role in tissue repair and regeneration

After tissue damage, a series of molecular and cellular events are initiated to promote tissue repair and regeneration to restore its original structure and function. These events include inter-cell communication, cell proliferation, cell migration, extracellular matrix differentiation, and other critical biological processes. Glycosylation is the crucial conservative and universal post-translational modification in all eukaryotic cells [1], with influential roles in intercellular recognition, regulation, signaling, immune response, cellular transformation, and disease development. Studies have shown that abnormally glycosylation of proteins is a well-recognized feature of cancer cells, and specific glycan structures are considered markers of tumor development. There are many studies on gene expression and regulation during tissue repair and regeneration. Still, there needs to be more knowledge of complex carbohydrates' effects on tissue repair and regeneration, such as glycosylation. Here, we present a review of studies investigating protein glycosylation in the tissue repair and regeneration process.

Sterols from Centaurea pumilio L. with cell proliferative activity: In vitro and in silico studies

Numerous studies highlighted the impact of natural products, particularly phytosterols, in wound healing while providing less expensive alternatives to chemically synthesized drugs, with less side effects. Centaurea pumilio L. (family Asteraceae) is a rare and endangered species of genus Centaurea with few reports concerning its chemistry. Our phytochemical investigation for the non-polar fraction of its aerial parts led to the isolation and identification of the new compound (6) identified as stigmast-1,5-dien-3-O-β-d-glucopyranoside along with five known sterols and triterpenes (1–5) identified as taraxasterol, β-sitosterol, stigmasterol, β-sitosterol glucoside, and stigmasterol-3-O-β-d-glucopyranoside. Structures of the isolated compounds have been characterized using 1D, 2D NMR, and mass spectral analyses. The cell viability and proliferative activity of the isolated compounds were evaluated using an MTT assay on cultured human primary umbilical vein endothelial cells (HUVEC). None of the compounds exhibited any sign of cytotoxicity. Nonetheless, compounds 5 and 6 moderately enhanced the HUVEC cell growth by 14 and 16%, respectively, at the maximal tested dose (50 µg/mL). As inhibition of glycogen synthase kinase 3-β (GSK3-β) enzyme is important to enhance the wound healing process; therefore, molecular docking was performed to understand the possible interactions between bioactive compounds 5 and 6 and GSK-3β binding pocket active amino acid residues. Both compounds were able to bind to the substrate‑binding site of GSK-3β and potentially interact with the key active site residues, forming strong π and hydrogen interactions with the catalytic site residues, revealing lower binding energy (−7.185 and −6.303 kcal/mol, respectively) than that of indirubin-3-monooxime (−5.303 kcal/mol); thereby representing strong natural replacements candidates for GSK-3β inhibitors.

Recent trends in diabetic wound healing with nanofibrous scaffolds

There is an emphasis in this review on nanofibrous scaffolds (NFSs) in diabetic wound healing, as well as their mechanisms and recent advancements. Diabetes-related complex wounds pose an important problem to humanity, due to the fact that their chronic nature can lead to serious complications including sepsis and amputations. Despite the fact that there are certain therapy options available for diabetic wound healing, these options are either ineffective or intrusive, making clinical intervention difficult. Clinical research is also challenged by the emergence of bacterial resistance to standard antibiotics. However, research into nanotechnology, in particular NFSs, is growing swiftly and has a positive impact on the treatment of diabetic wounds. For instance, SpinCare™, developed by Nanomedic Technologies Ltd, has successfully finished clinical testing and can re-epithelialize second-degree burns and chronic diabetic wounds in 7 and 14 days, respectively. In this review, we discussed homologous studies as well as other recent research studies on diabetic wound healing using NFSs.

PGE2 Produced by Exogenous MSCs Promotes Immunoregulation in ARDS Induced by Highly Pathogenic Influenza A through Activation of the Wnt-β-Catenin Signaling Pathway

Acute respiratory distress syndrome is an acute respiratory failure caused by cytokine storms; highly pathogenic influenza A virus infection can induce cytokine storms. The innate immune response is vital in this cytokine storm, acting by activating the transcription factor NF-κB. Tissue injury releases a danger-associated molecular pattern that provides positive feedback for NF-κB activation. Exogenous mesenchymal stem cells can also modulate immune responses by producing potent immunosuppressive substances, such as prostaglandin E2. Prostaglandin E2 is a critical mediator that regulates various physiological and pathological processes through autocrine or paracrine mechanisms. Activation of prostaglandin E2 results in the accumulation of unphosphorylated β-catenin in the cytoplasm, which subsequently reaches the nucleus to inhibit the transcription factor NF-κB. The inhibition of NF-κB by β-catenin is a mechanism that reduces inflammation.

The biological and physiological impact of the performance of wound dressings

Chronic wounds affect millions globally and are a huge financial burden. Whilst there are many wound dressings commercially available to manage these wounds, the complexity of the repair process makes it difficult to select the right dressing for the right wound at the right time. Thus, in this narrative review, we have examined reasons why wounds fail to heal, summarised the pathophysiology of the chronic wound environment and provided an evidence-based, clinically-relevant compilation of the published literature relevant to dressing design and evaluation. This has highlighted the need for a deeper understanding of wound exudates, how exudates change throughout the healing process, and how they are impacted by different dressing materials. Studies assessing biochemical and biophysical changes in exudates throughout the healing process are extremely valuable in this regard, enhancing both our understanding of the wound healing process and the ability to assess dressing performance. In addition, this knowledge allows us to replicate various wound conditions in the laboratory, and develop clinically-relevant models for testing current and new dressings, therefore providing a more comprehensive understanding of how and when they should be used. This approach makes the use of dressings more effective, thereby improving outcomes, and reducing the economic burden of chronic wounds.

Dressing Materials: A Comprehensive Review

Injury to the skin provides a difficult challenge, as wound healing is a complex and dynamic process. Wound healing process recruits three different phases: inflammation, proliferation, and maturation. The sequence of events involved in wound healing can be affected by numerous disease processes, resulting in chronic, non-healing wounds that give significant discomfort and distress to the patients while draining the medical fraternity of enormous resources. Wound tissue never reaches its pre-injured strength and multiple aberrant healing states can result in chronic non-healing wounds. There is a growing concern about the usage of correct materials for wound dressings. The development of new and effective treatments in wound care still remains an area of intense research. There are a number of wound dressings available in the market. The objective of the article is to enhance knowledge about characteristics of an ideal wound dressing and guide in finding the correct dressing material. It also provides a detailed classification of traditional and modern wound dressings.

The association of wound factors and symptoms of fatigue and pain with wound healing in chronic venous leg ulcers

The purpose of this study was: (1) to characterise the association of wound area, wound exudate C-reactive protein (CRP), broad-spectrum matrix metalloprotease protein (MMPs), and symptoms of fatigue and pain in individuals with chronic venous leg ulcers (CVLUs) over time and (2) to identify factors associated with the wound healing trajectory in CVLUs. Seventy four participants with CVLU who received weekly sharp debridement were recruited from a wound care clinic during the 8-week study period. To examine associations among wound CRP, MMPs, pain, fatigue, and wound healing trajectory over time, we calculated Bayes factors (BF) based on a linear mixed model. The mean age of participants was 71.8 (SD = 9.8) and the mean wound area was 2278 mm² (SD = 7085 mm² ) at baseline. Higher fatigue was strongly associated with higher MMPs (BF = 9, 95% HDI: [-.05, .43]), lower CRP (BF = 11, 95% HDI: [-.02, .002]), and large areas of wound (BF = 20, 95% HDI: [-.001, .01]). Higher CRP and MMPs activity in wound exudate and higher fatigue were associated with a larger wound area. To facilitate wound healing, clinicians need to utilise the multifactorial approach, which includes wound treatment and management of symptoms such as pain and fatigue, because of the molecular and psycho-behavioural factors involved in wound healing.

Adventitial adaptive immune cells are associated with ascending aortic dilatation in patients with a bicuspid aortic valve

Background

Bicuspid aortic valve (BAV) is associated with ascending aorta aneurysms and dissections. Presently, genetic factors and pathological flow patterns are considered responsible for aneurysm formation in BAV while the exact role of inflammatory processes remains unknown.

Methods

In order to objectify inflammation, we employ a highly sensitive, quantitative immunohistochemistry approach. Whole slides of dissected, dilated and non-dilated ascending aortas from BAV patients were quantitatively analyzed.

Results

Dilated aortas show a 4-fold increase of lymphocytes and a 25-fold increase in B lymphocytes in the adventitia compared to non-dilated aortas. Tertiary lymphoid structures with B cell follicles and helper T cell expansion were identified in dilated and dissected aortas. Dilated aortas were associated with an increase in M1-like macrophages in the aorta media, in contrast the number of M2-like macrophages did not change significantly.

Conclusion

This study finds unexpected large numbers of immune cells in dilating aortas of BAV patients. These findings raise the question whether immune cells in BAV aortopathy are innocent bystanders or contribute to the deterioration of the aortic wall.

pH-Responsive wound dressings: advances and prospects

Wound healing is a complex and dynamic process, in which the pH value plays an important role in reflecting the wound status. Wound dressings are materials that are able to accelerate the healing process. Among the multifunctional advanced wound dressings developed in recent years, pH-responsive wound dressings, especially hydrogels, show great potential owing to their unique properties of adjusting their functions according to the wound conditions, thereby allowing the wound to heal in a regulated manner. However, a comprehensive review of pH-responsive wound dressings is lacking. This review summarizes the design strategies and advanced functions of pH-responsive hydrogel wound dressings, including their excellent antibacterial properties and significant pro-healing abilities. Other advanced pH-responsive materials, such as nanofibers, composite films, nanoparticle clusters, and microneedles, are also classified and discussed. Next, the pH-monitoring functions of pH-responsive wound dressings and the related pH indicators are summarized in detail. Finally, the achievements, challenges, and future development trends of pH-responsive wound dressings are discussed.

Jellyfishes—Significant Marine Resources with Potential in the Wound-Healing Process: A Review

The wound-healing process is a significant area of interest in the medical field, and it is influenced by both external and patient-specific factors. The aim of this review paper is to highlight the proven wound-healing potential of the biocompounds found in jellyfish (such as polysaccharide compounds, collagen, collagen peptides and amino acids). There are aspects of the wound-healing process that can benefit from polysaccharides (JSPs) and collagen-based materials, as these materials have been shown to limit exposure to bacteria and promote tissue regeneration. A second demonstrated benefit of jellyfish-derived biocompounds is their immunostimulatory effects on growth factors such as (TNF-α), (IFN-γ) and (TGF), which are involved in wound healing. A third benefit of collagens and polysaccharides (JSP) is their antioxidant action. Aspects related to chronic wound care are specifically addressed, and within this general theme, molecular pathways related to tissue regeneration are explored in depth. Only distinct varieties of jellyfish that are specifically enriched in the biocompounds involved in these pathways and live in European marine habitats are presented. The advantages of jellyfish collagens over mammalian collagens are highlighted by the fact that jellyfish collagens are not considered transmitters of diseases (spongiform encephalopathy) or various allergic reactions. Jellyfish collagen extracts stimulate an immune response in vivo without inducing allergic complications. More studies are needed to explore more varieties of jellyfish that can be exploited for their biocomponents, which may be useful in wound healing.

Induced pluripotent stem cell-derived extracellular vesicles promote wound repair in a diabetic mouse model via an anti-inflammatory immunomodulatory mechanism

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have recently been widely explored in clinical trials for treatment of diseases with complex pathophysiology. However, production of MSC EVs is currently hampered by donor-specific characteristics and limited ex vivo expansion capabilities before decreased potency, thus restricting their potential as a scalable and reproducible therapeutic. Induced pluripotent stem cells (iPSCs) represent a self-renewing source for obtaining differentiated iPSC-derived MSCs (iMSCs), circumventing both scalability and donor variability concerns for therapeutic EV production. Thus, we initially sought to evaluate the therapeutic potential of iMSC EVs. Interestingly, while utilizing undifferentiated iPSC EVs as a control, we found that their vascularization bioactivity was similar and their anti-inflammatory bioactivity was superior to donor-matched iMSC EVs in cell-based assays. To supplement this initial in vitro bioactivity screen, we employed a diabetic wound healing mouse model where both the pro-vascularization and anti-inflammatory activity of these EVs would be beneficial. In this in vivo model, iPSC EVs more effectively mediated inflammation resolution within the wound bed. Combined with the lack of additional differentiation steps required for iMSC generation, these results support the use of undifferentiated iPSCs as a source for therapeutic EV production with respect to both scalability and efficacy.

Recent Tissue Engineering Approaches to Mimicking the Extracellular Matrix Structure for Skin Regeneration

Inducing tissue regeneration in many skin defects, such as large traumatic wounds, burns, other physicochemical wounds, bedsores, and chronic diabetic ulcers, has become an important clinical issue in recent years. Cultured cell sheets and scaffolds containing growth factors are already in use but have yet to restore normal skin tissue structure and function. Many tissue engineering materials that focus on the regeneration process of living tissues have been developed for the more versatile and rapid initiation of treatment. Since the discovery that cells recognize the chemical-physical properties of their surrounding environment, there has been a great deal of work on mimicking the composition of the extracellular matrix (ECM) and its three-dimensional network structure. Approaches have used ECM constituent proteins as well as morphological processing methods, such as fiber sheets, sponges, and meshes. This review summarizes material design strategies in tissue engineering fields, ranging from the morphology of existing dressings and ECM structures to cellular-level microstructure mimicry, and explores directions for future approaches to precision skin tissue regeneration.

Status and Future Scope of Soft Nanoparticles-Based Hydrogel in Wound Healing

Wounds are alterations in skin integrity resulting from any type of trauma. The healing process is complex, involving inflammation and reactive oxygen species formation. Therapeutic approaches for the wound healing process are diverse, associating dressings and topical pharmacological agents with antiseptics, anti-inflammatory, and antibacterial actions. Effective treatment must maintain occlusion and moisture in the wound site, suitable capacity for the absorption of exudates, gas exchange, and the release of bioactives, thus stimulating healing. However, conventional treatments have some limitations regarding the technological properties of formulations, such as sensory characteristics, ease of application, residence time, and low active penetration in the skin. Particularly, the available treatments may have low efficacy, unsatisfactory hemostatic performance, prolonged duration, and adverse effects. In this sense, there is significant growth in research focusing on improving the treatment of wounds. Thus, soft nanoparticles-based hydrogels emerge as promising alternatives to accelerate the healing process due to their improved rheological characteristics, increased occlusion and bioadhesiveness, greater skin permeation, controlled drug release, and a more pleasant sensory aspect in comparison to conventional forms. Soft nanoparticles are based on organic material from a natural or synthetic source and include liposomes, micelles, nanoemulsions, and polymeric nanoparticles. This scoping review describes and discusses the main advantages of soft nanoparticle-based hydrogels in the wound healing process. Herein, a state-of-the-art is presented by addressing general aspects of the healing process, current status and limitations of non-encapsulated drug-based hydrogels, and hydrogels formed by different polymers containing soft nanostructures for wound healing. Collectively, the presence of soft nanoparticles improved the performance of natural and synthetic bioactive compounds in hydrogels employed for wound healing, demonstrating the scientific advances obtained so far.

Obesity and Wound Healing: Focus on Mesenchymal Stem Cells

Chronic wounds represent nowadays a major challenge for both clinicians and researchers in the regenerative setting. Obesity represents one of the major comorbidities in patients affected by chronic ulcers and therefore diverse studies aimed at assessing possible links between these two morbid conditions are currently ongoing. In particular, adipose tissue has recently been described as having metabolic and endocrine functions rather than serving as a mere fat storage deposit. In this setting, adipose-derived stem cells, a peculiar subset of mesenchymal stromal/stem cells (MSCs) located in adipose tissue, have been demonstrated to possess regenerative and immunological functions with a key role in regulating both adipocyte function and skin regeneration. The aim of the present review is to give an overview of the most recent findings on wound healing, with a special focus on adipose tissue biology and obesity.

Adipose Tissue-Derived Components: From Cells to Tissue Glue to Treat Dermal Damage

In recent decades, adipose tissue transplantation has become an essential treatment modality for tissue (volume) restoration and regeneration. The regenerative application of adipose tissue has only recently proven its usefulness; for example, the method is useful in reducing dermal scarring and accelerating skin-wound healing. The therapeutic effect is ascribed to the tissue stromal vascular fraction (tSVF) in adipose tissue. This consists of stromal cells, the trophic factors they secrete and the extracellular matrix (ECM), which have immune-modulating, pro-angiogenic and anti-fibrotic properties. This concise review focused on dermal regeneration using the following adipose-tissue components: adipose-tissue-derived stromal cells (ASCs), their secreted trophic factors (ASCs secretome), and the ECM. The opportunities of using a therapeutically functional scaffold, composed of a decellularized ECM hydrogel loaded with trophic factors of ASCs, to enhance wound healing are explored as well. An ECM-based hydrogel loaded with trophic factors combines all regenerative components of adipose tissue, while averting the possible disadvantages of the therapeutic use of adipose tissue, e.g., the necessity of liposuction procedures with a (small) risk of complications, the impossibility of interpatient use, and the limited storage options.

The effect of high-voltage monophasic pulsed current on diabetic ulcers and their potential pathophysiologic factors: A systematic review and meta-analysis

The present review was conducted to determine the efficacy of high-voltage monophasic pulsed current (HVMPC) in treating diabetic ulcers, assess its effect on skin lesions with each of the pathophysiologic factors potentially contributing to diabetic ulcers, evaluate its safety, and identify treatment parameters. Electronic search of PubMed, Scopus, PEDro and Google Scholar databases was conducted. The revised tool for assessing risk of bias in randomised trials (RoB 2), the risk of bias in non-randomised studies-of interventions (ROBINS-I) and the Joanna Briggs Institute (JBI) critical appraisal tool were used to assess risk of bias and methodological quality. Overall quality of evidence was determined using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) principles. Thirty-two studies matched the eligibility criteria, and included 1061 patients with 1103 skin lesions of selected aetiologies; 12 randomised controlled trials were included in quantitative synthesis. HVMPC plus standard wound care (SWC) likely increased the probability of complete wound healing of pressure ulcers (PrUs) compared with sham/no stimulation plus SWC; relative risk (RR) 2.08; 95% CI: [1.42, 3.04], p = 0.0002; I²  = 0%, p = 0.61; eight studies, 358 ulcers. Although conclusive evidence regarding the effect of HVMPC on diabetic ulcers was not found, collateral evidence might suggest a potential benefit. Direct evidence, with moderate certainty, may support its efficacy in treating PrUs, albeit few adverse reactions were reported. Other observations, moreover, might indicate that this efficacy may not be limited to PrUs. Nonetheless, several aspects remain to be clarified for safe and effective application of electrical stimulation for wound healing.

Cold Plasma Treatment Promotes Full-thickness Healing of Skin Wounds in Murine Models

Cold plasma can be beneficial for promoting skin wound healing and has a high potential of being effectively used in treating various wounds. Our aim was to verify the effect of cold plasma in accelerating wound healing and investigate its underlying mechanism in vitro and in vivo. For the in vivo experiments, 2 full-thickness dermal wounds were created in each mouse (n = 30). While one wound was exposed to 2 daily plasma treatments for 3 min, the other wound served as a control. The wounds were evaluated by imaging and histological analyses at 4, 7, and 11 days post the wound infliction process. Immunohistochemical studies were also performed at the same time points. In vitro proliferation and scratch assay using HaCaT keratinocytes and fibroblasts were performed. The expression levels of wound healing-related genes were analyzed by real-time polymerase chain reaction and western blot analysis. On day 7, the wound healing rates were 53.94% and 63.58% for the control group and the plasma-treated group, respectively. On day 11, these rates were 76.05% and 93.44% for the control and plasma-treated groups, respectively, and the difference between them was significant (P = .039). Histological analysis demonstrated that plasma treatment promotes the formation of epidermal keratin and granular layers. Immunohistochemical studies also revealed that collagen 1, collagen 3, and alpha-smooth muscle actin appeared more abundantly in the plasma-treated group than in the control group. In vitro, the proliferation of keratinocytes was promoted by plasma exposure. Scratch assay showed that fibroblast exposure to plasma increased their migration. The expression levels of collagen 1, collagen 3, and alpha-smooth muscle actin were elevated upon plasma treatment. In conclusion, cold plasma can accelerate skin wound healing and is well tolerated.

Sheng-ji Hua-yu ointment ameliorates cutaneous wound healing in diabetes via up-regulating CCN1

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic ulcers (DUs) are one of the most severe complications of diabetes, and efficacious therapeutic means are currently lacking. Sheng-ji Hua-yu (SJHY) ointment is a classical Chinese traditional prescription that can significantly attenuate DU defects, but the specific mechanism remains to be fully elucidated.

AIM OF THE STUDY

In order to verify the underlying mechanism of SJHY ointment in accelerating the closure of DUs.

MATERIALS AND METHODS

Modular pharmacology and molecular docking were utilized to predict the therapeutic targets of SJHY ointment against DUs. Male db/db diabetic mice and HaCaT cell models induced by methylglyoxal were used to validate the findings.

RESULTS

CCN1 was proven to be the core target of SJHY ointment involved in DUs treatment. CCN1 up-regulated by SJHY treatment (0.5 g/cm²/day) at the mRNA and protein levels was detected on Day9 after wounding. With CCN1 knockdown, accelerated cell proliferation, migration, and anti-inflammatory effect of SJHY treatment (10 mg/L) were reversed.

CONCLUSIONS

SJHY ointment ameliorates cutaneous wound healing by up-regulating CCN1.

Hyperdry Human Amniotic Membrane as a Protective Dressing for Open Wounds With Exposed Bowel in Mice

INTRODUCTION

An enteroatmospheric fistula forms when the exposed bowel is perforated with chronic enteric fistula formation. Currently, there is no established preventative method for this condition. Hyperdry (HD) amniotic membrane (AM) can promote early granulation tissue formation on the exposed viscera and is suitable for dressing intractable wounds as it possesses anti-inflammatory, antibacterial, and immunomodulatory properties. This study investigated whether HD-AM promotes early formation of blood vessel-containing granulation tissue for enteroatmospheric fistula treatment.

METHODS

An experimental animal model of an open wound with exposed bowel was developed. A 15 × 20 mm wound was prepared on the abdomen of Institute of Cancer Research mice, and the HD-AM was placed. The mice were assigned to one of the following groups: HD-AM group, in which the stromal layer of the HD-AM was placed in contact with the exposed bowel; HD-AM UD group, in which the epithelial layer of the HD-AM was placed in contact with the exposed bowel; and the HD-AM (-) or control group, in which the HD-AM was not used.

RESULTS

On postoperative days 7 and 14, granulation tissue thickness significantly increased in the HD-AM and HD-AM UD groups compared with that in the HD-AM (-) group. Macrophages accumulated in the HD-AM epithelium only in the HD-AM group. During HD-AM contact, a subset of invading macrophages switched from M1 to M2 phenotype.

CONCLUSIONS

HD-AM is a practical wound dressing with its scaffolding function, regulation of TGF β-1 and C-X-C motif chemokine 5 (CXCL-5), and ability to induce M1-to-M2 macrophage conversion.

Photomodulative effects of low-level laser therapy on tracheal fenestration developed in in vivo model

The effect of low-level laser therapy (LLLT) on variable mucosal lesions in the upper aerodigestive tract has been reported. However, the effect of LLLT on tracheostomy sites or tracheal fenestration is rarely reported. In this study, we evaluate the effect of LLLT performed using 635 nm laser light based on a cylindrical diffuser and an animal model with tracheal fenestration. An animal model of tracheal fenestration is developed by suturing the trachea to the skin after performing a vertical tracheostomy from the second to the fifth tracheal ring of Wistar rats (male, body weight 200-250 g). LLLT (spot size: 2 cm²) is conducted once daily for five days using a handheld cylindrical device. Twenty-four rats are randomly assigned to a no-therapy or LLLT group with an energy density of 20 J/cm². Histological analysis is performed at 7 and 14 days after tracheal fenestration. Irradiation at the tracheal fenestration site with an energy density of 20 J/cm² improves the wound healing, as shown at 2 weeks after tracheostomy. Histological analysis shows significantly decreased acute inflammation and granulation tissue, as well as better cartilage regeneration and less tracheal wall thickening. Therefore, LLLT demonstrates therapeutic potential for preventing tracheal stenosis and granuloma after tracheostomy.

The Impact of Prior Infection With SARS-Cov-2 on Surgical Outcomes in Patients Undergoing Abdominal Body Contouring Procedures

BACKGROUND

There is evidence of increased postoperative complications in patients who have recovered from SARS-CoV-2. However, previous studies have not examined this effect in abdominal contouring procedures.

METHODS

A retrospective review was conducted for all patients who underwent abdominoplasty or panniculectomy at our institution from March 2020 to November 2021. Patients were separated into cohorts via preoperative history of SARS-CoV-2 infections. Variables collected include demographic data, concurrent comorbidities, postoperative complications, readmission/reoperation, and length of stay. Parametric, nonparametric, and multivariable regression modeling was used for analysis.

RESULTS

Of the 181 patients included, 14 (7.7%) had a prior SARS-CoV-2 infection. Average time from infection to surgery was 250 days. The mean age and Charlson Comorbidity Index for nonexposed and exposed patients were 45.4 and 45.9 years, and 1.24 and 1.36 points. Patients with prior SARS-CoV-2 infection were more likely to have chronic kidney disease (odds ratio [OR], 6.79; P = 0.017) and undergo abdominoplasties compared with panniculectomies (OR, 4.43; P = 0.039). There were no other significant differences in patient or operative characteristics between the cohorts. Compared with those with no history of infection, patients with prior infections had increased odds of postoperative complications such as delayed wound healing (OR, 27.67; P < 0.001). No other significant associations were found between prior SARS-CoV-2 infection and perioperative outcomes.

CONCLUSION

Prior SARS-CoV-2 infections may be associated with increased incidence of delayed wound healing despite a significant time lag between the time of infection and operation. Further studies are needed to elucidate the exact relationship and mechanism of action behind these findings.

Modulation of Macrophage Function by Bioactive Wound Dressings with an Emphasis on Extracellular Matrix-Based Scaffolds and Nanofibrous Composites

Bioactive wound dressings that are capable of regulating the local wound microenvironment have attracted a very large interest in the field of regenerative medicine. Macrophages have many critical roles in normal wound healing, and the dysfunction of macrophages significantly contributes to impaired or non-healing skin wounds. Regulation of macrophage polarization towards an M2 phenotype provides a feasible strategy to enhance chronic wound healing, mainly by promoting the transition of chronic inflammation to the proliferation phase of wound healing, upregulating the level of anti-inflammatory cytokines around the wound area, and stimulating wound angiogenesis and re-epithelialization. Based on this, modulation of macrophage functions by the rational design of bioactive scaffolds has emerged as a promising way to accelerate delayed wound healing. This review outlines current strategies to regulate the response of macrophages using bioactive materials, with an emphasis on extracellular matrix-based scaffolds and nanofibrous composites.