Skin: Histology and Physiology of Wound Healing

Progress in the application of artificial intelligence in skin wound assessment and prediction of healing time

Since the 1970s, artificial intelligence (AI) has played an increasingly pivotal role in the medical field, enhancing the efficiency of disease diagnosis and treatment. Amidst an aging population and the proliferation of chronic disease, the prevalence of complex surgeries for high-risk multimorbid patients and hard-to-heal wounds has escalated. Healthcare professionals face the challenge of delivering safe and effective care to all patients concurrently. Inadequate management of skin wounds exacerbates the risk of infection and complications, which can obstruct the healing process and diminish patients' quality of life. AI shows substantial promise in revolutionizing wound care and management, thus enhancing the treatment of hospitalized patients and enabling healthcare workers to allocate their time more effectively. This review details the advancements in applying AI for skin wound assessment and the prediction of healing timelines. It emphasizes the use of diverse algorithms to automate and streamline the measurement, classification, and identification of chronic wound healing stages, and to predict wound healing times. Moreover, the review addresses existing limitations and explores future directions.

Aloesin-loaded chitosan/cellulose-based scaffold promotes skin tissue regeneration

Skin wound healing and regeneration is very challenging across the world as simple or acute wounds can be transformed into chronic wounds or ulcers due to foreign body invasion, or diseases like diabetes or cancer. The study was designed to develop a novel bioactive scaffold, by loading aloesin to chitosan-coated cellulose scaffold, to cure full-thickness skin wounds. The physiochemical characterization of the scaffold was carried out using scanning electron microscopy (SEM) facilitated by energy-dispersive spectrophotometer (EDS), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). The results indicated the successful coating of chitosan and aloesin on cellulose without any physical damage. The drug release kinetics confirmed the sustained release of aloesin by showing a cumulative release of up to 88 % over 24 h. The biocompatibility of the aloesin-loaded chitosan/cellulose (AlCsCFp) scaffold was evaluated by the WST-8 assay that confirmed the significantly increased adherence and proliferation of fibroblasts on the AlCsCFp scaffold. The in vivo wound healing study showed that both 0.05 % and 0.025 % AlCsCFp scaffolds have significantly higher wound closure rates (i.e. 88.2 % and 95.6 % approximately) as compared to other groups. This showed that novel composite scaffold has a wound healing ability. Furthermore, histological and gene expression analysis demonstrated that the scaffold also induced cell migration, angiogenesis, re-epithelialization, collagen deposition, and tissue granulation formation. Thus, it is concluded that the aloesin-loaded chitosan/cellulose-based scaffold has great therapeutic potential for being used in wound healing applications in the clinical setting in the future.

Stem Cells and Nanofibers for Skin Regeneration and Wound Healing

Stem cells have been attractive targets for tissue regeneration due to their inherent ability to differentiate into various specialized cell types; however, efforts for stem cell transplantation for the treatment of degenerated tissues have been hampered by the propensity of some stem cell types to form teratomas and the lessened viability of stem cells after transplantation. These disadvantages can be prevented using tailored extracellular matrix-like materials that can be used as an aid for the transplantation of stem cells. Nanomaterials, in particular nanofibers, have great potential to be used as extracellular matrix-like materials for this purpose. In this article, we will review the use of stem cells and nanofibers for skin regeneration and wound healing.

Adipose-Derived Stem Cell Exosomes Facilitate Diabetic Wound Healing: Mechanisms and Potential Applications

Wound healing in diabetic patients is frequently hampered. Adipose-derived stem cell exosomes (ADSC-eoxs), serving as a crucial mode of intercellular communication, exhibit promising therapeutic roles in facilitating wound healing. This review aims to comprehensively outline the molecular mechanisms through which ADSC-eoxs enhance diabetic wound healing. We emphasize the biologically active molecules released by these exosomes and their involvement in signaling pathways associated with inflammation modulation, cellular proliferation, vascular neogenesis, and other pertinent processes. Additionally, the clinical application prospects of the reported ADSC-eoxs are also deliberated. A thorough understanding of these molecular mechanisms and potential applications is anticipated to furnish a theoretical groundwork for combating diabetic wound healing.

Efficient healing of diabetic wounds by MSC-EV-7A composite hydrogel via suppression of inflammation and enhancement of angiogenesis

Diabetes mellitus (DM) is characterized by prolonged hyperglycemia, impaired vascularization, and serious complications, such as blindness and chronic diabetic wounds. About 25% of patients with DM are estimated to encounter impaired healing of diabetic wounds, often leading to lower limb amputation. Multiple factors are attributed to the non-healing of diabetic wounds, including hyperglycaemia, chronic inflammation, and impaired angiogenesis. It is imperative to develop more efficient treatment strategies to tackle healing difficulties in diabetic wounds. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are promising for diabetic wound healing considering their anti-inflammatory, pro-angiogenic and pro-proliferative activities. A histone deacetylase 7 (HDAC7)-derived 7-amino-acid peptide (7A) was shown to be highly effective for angiogenesis. However, it has never been investigated whether MSC-EVs are synergistic with 7A for the healing of diabetic wounds. Herein, we propose that MSC-EVs can be combined with 7A to greatly promote diabetic wound healing. The combination of EVs and 7A significantly improved the migration and proliferation of skin fibroblasts. Moreover, EVs alone significantly suppressed LPS-induced inflammation in macrophages, and notably, the combination treatment showed an even better suppression effect. Importantly, the in vivo study revealed that the combination therapy consisting of EVs and 7A in an alginate hydrogel was more efficient for the healing of diabetic wounds in rats than monotherapy using either EV or 7A hydrogels. The underlying mechanisms include suppression of inflammation, improvement of skin cell proliferation and migration, and enhanced collagen fiber disposition and angiogenesis in wounds. In summary, the MSC-EV-7A hydrogel potentially constitutes a novel therapy for efficient healing of chronic diabetic wounds.

Wound Healing Effect of Lippia sidoides and Myracrodruon urundeuva Nanogel

Wound healing is a natural regenerative response to tissue injury and the conventional treatments consists of the use wound dressings with local administration of medicines, but, in some cases, are only partially effective and limited by toxicity or ineffective anti-microbial protection. Medicinal plants such as Lippia sidoides and Myracrodruon urundeuva have shown interesting pharmacological activities, allied to this, the association of these medicinal plants and nanotechnology, could mean an advantage in relation to classical approach. This study investigated the effect of a nanogel loaded with Lippia sidoides essential oil and Myracrodruon urundeuva extract (NAA) in an excisional wound healing model in rats. Animals were anesthetized and skin wounds were made using a metal punch. The groups were treated with vehicle, NAA or collagenase gel, for 7, 14 or 21 days and then sacrificed for tissue analysis. NAA did not show acute dermal irritation, further significantly reduced (p<0.05) the final wound area, accelerated the wound contraction and organization of collagen in the group treated for 14 days. The data presented here demonstrate the therapeutic potential for the use of nanotechnology associated with medicinal plants and provides evidence that corroborate with the use of L. sidoides and M. urundeuva as healing medicinal plants.

Significant Enhancement of Fibroblast Migration, Invasion, and Proliferation by Exosomes Loaded with Human Fibroblast Growth Factor 1

Exosomes possess several inherent properties that make them ideal for biomedical applications, including robust stability, biocompatibility, minimal immunogenicity, and the ability to cross biological barriers. These natural nanoparticles have recently been developed as drug delivery vesicles. To do so, therapeutic molecules must be efficiently loaded into exosomes first. Very recently, we developed a cell-penetrating peptide (CPP)-based platform for loading of nucleic acids and small molecules into exosomes by taking advantage of the membrane-penetration power of CPPs. Here, we extended this simple but effective platform by loading a protein cargo into exosomes isolated from either mesenchymal stem cells from three different sources or two different cancer cell lines. The protein cargo is a fusion protein YARA-FGF1-GFP through the covalent conjugation of a model CPP called YARA to human fibroblast growth factor 1 (FGF1) and green fluorescence protein (GFP). Loading of YARA-FGF1-GFP into exosomes was time-dependent and reached a maximum of about 1600 YARA-FGF1-GFP molecules in each exosome after 16 h. The ladened exosomes were effectively internalized by mammalian cells, and subsequently, the loaded protein cargo YARA-FGF1-GFP was delivered intracellularly. In comparison to YARA, YARA-FGF1-GFP, the unloaded exosomes, and the exosomes loaded with YARA, the exosomes loaded with YARA-FGF1-GFP substantially promoted the migration, proliferation, and invasion capabilities of mouse and human fibroblasts, which are important factors for wound repair. The work extended our CPP-based exosomal cargo loading platform and established a foundation for developing novel wound-healing therapies using exosomes loaded with FGF1 and other growth factors.

Hydrogels and Wound Healing: Current and Future Prospects

The care and rehabilitation of acute and chronic wounds have a significant social and economic impact on patients and global health. This burden is primarily due to the adverse effects of infections, prolonged recovery, and the associated treatment costs. Chronic wounds can be treated with a variety of approaches, which include surgery, negative pressure wound therapy, wound dressings, and hyperbaric oxygen therapy. However, each of these strategies has an array of limitations. The existing dry wound dressings lack functionality in promoting wound healing and exacerbating pain by adhering to the wound. Hydrogels, which are commonly polymer-based and swell in water, have been proposed as potential remedies due to their ability to provide a moist environment that facilitates wound healing. Their unique composition enables them to absorb wound exudates, exhibit shape adaptability, and be modified to incorporate active compounds such as growth factors and antibacterial compounds. This review provides an updated discussion of the leading natural and synthetic hydrogels utilized in wound healing, details the latest advancements in hydrogel technology, and explores alternate approaches in this field. Search engines Scopus, PubMed, Science Direct, and Web of Science were utilized to review the advances in hydrogel applications over the last fifteen years.

Jelleine, a Family of Peptides Isolated from the Royal Jelly of the Honey Bees (Apis mellifera), as a Promising Prototype for New Medicines: A Narrative Review

The jelleine family is a group of four peptides (jelleines I-IV) originally isolated from the royal jelly of honey bee (Apis mellifera), but later detected in some honey samples. These oligopeptides are composed of 8-9 amino acid residues, positively charged (+2 to +3 at pH 7.2), including 38-50% of hydrophobic residues and a carboxamide C-terminus. Jelleines, generated by processing of the C-terminal region of major royal jelly proteins 1 (MRJP-1), play an important biological role in royal jelly conservation as well as in protecting bee larvae from potential pathogens. Therefore, these molecules present numerous benefits for human health, including therapeutic purposes as shown in preclinical studies. In this review, we aimed to evaluate the biological effects of jelleines in addition to characterising their toxicities and stabilities. Jelleines I-III have promising antimicrobial activity and low toxicity (LD50 > 1000 mg/Kg). However, jelleine-IV has not shown relevant biological potential. Jelleine-I, but not the other analogues, also has antiparasitic, healing, and pro-coagulant activities in addition to indirectly modulating tumor cell growth and controlling the inflammatory process. Although it is sensitive to hydrolysis by proteases, the addition of halogens increases the chemical stability of these molecules. Thus, these results suggest that jelleines, especially jelleine-I, are a potential target for the development of new, effective and safe therapeutic molecules for clinical use.

Advances of regenerated and functionalized silk biomaterials and application in skin wound healing

The cocoon silk of silkworms (Bombyx mori) has multiple potential applications in biomedicine due to its good biocompatibility, mechanical properties, degradability, and plasticity. Numerous studies have confirmed that silk material dressings are more effective than traditional ones in the skin wound healing process. Silk material research has recently moved toward functionalized biomaterials and achieved remarkable results. Herein, we summarize the recent advances in functionalized silk materials and their efficacy in skin wound healing. In particular, transgenic technology has realized the specific expression of human growth factors in the silk glands of the silkworms, which lays the foundation for fabricating novel and low-cost functionalized materials. Without a green and safe preparation process, the best raw silk materials cannot be made into medically safe products. Therefore, we provide an overview of green and gentle approaches for silk degumming and silk sericin (SS) extraction. Moreover, we summarize and discuss the processing methods of silk fibroin (SF) and SS materials and their potential applications, such as burns, diabetic wounds, and other wounds. This review aims to enhance our understanding of new advances and directions in silk materials and guide future biomedical research.

Bioactive materials for in vivo sweat gland regeneration

Loss of sweat glands (SwGs) commonly associated with extensive skin defects is a leading cause of hyperthermia and heat stroke. In vivo tissue engineering possesses the potential to take use of the body natural ability to regenerate SwGs, making it more conducive to clinical translation. Despite recent advances in regenerative medicine, reconstructing SwG tissue with the same structure and function as native tissue remains challenging. Elucidating the SwG generation mechanism and developing biomaterials for in vivo tissue engineering is essential for understanding and developing in vivo SwG regenerative strategies. Here, we outline the cell biology associated with functional wound healing and the characteristics of bioactive materials. We critically summarize the recent progress in bioactive material-based cell modulation approaches for in vivo SwG regeneration, including the recruitment of endogenous cells to the skin lesion for SwG regeneration and in vivo cellular reprogramming for SwG regeneration. We discussed the re-establishment of microenvironment via bioactive material-mediated regulators. Besides, we offer promising perspectives for directing in situ SwG regeneration via bioactive material-based cell-free strategy, which is a simple and effective approach to regenerate SwG tissue with both fidelity of structure and function. Finally, we discuss the opportunities and challenges of in vivo SwG regeneration in detail. The molecular mechanisms and cell fate modulation of in vivo SwG regeneration will provide further insights into the regeneration of patient-specific SwGs and the development of potential intervention strategies for gland-derived diseases.

Shikonin potentiates skin wound healing in Sprague-Dawley rats by stimulating fibroblast and endothelial cell proliferation and angiogenesis

BACKGROUND

Shikonin, a major component of Lithospermum erythrorhizon, exerts anti-inflammatory and antibacterial effects and expedites wound healing. This study aims to evaluate the anti-inflammatory and antioxidant activities of shikonin in a Sprague-Dawley rat model and cell models using fibroblast and endothelial cells.

METHODS

The impact of shikonin on the activity of endothelial cells and fibroblasts was examined by cell counting kit 8 and wound-healing assays. A diabetic rat model was constructed, followed by wound creation for treatment with shikonin. Hematoxylin-eosin staining was used to assess pathological changes, and Masson's trichrome method to detect collagen deposition. Immunohistochemistry using antibodies against proliferating cell nuclear antigen and CD31 was conducted to detect proliferation and vascular density. Enzyme-linked immunosorbent assay and immunohistochemistry were carried out to assess pro-inflammatory and anti-inflammatory factor concentrations. Western blot and immunofluorescence were implemented to analyze oxidative stress-related protein expression.

RESULTS

Shikonin induced the activity of both fibroblasts and endothelial cells. Shikonin treatment contributed to facilitated wound healing and higher healing rates in rats. It also resulted in faster lesion debulking in tissues, reduced inflammatory infiltration, increased collagen deposition, and enhanced angiogenesis. Detection of markers at the wounds showed that shikonin accelerated cell proliferation, enhanced tissue remodeling, and inhibited oxidative stress.

CONCLUSION

Shikonin stimulates the proliferation and migration of fibroblasts and endothelial cells to promote angiogenesis and tissue remodeling, resulting in faster wound healing.

Biological Activity of Fermented Plant Extracts for Potential Dermal Applications

Fermented plant extracts (FPEs) are functional liquids formed as a result of the fermentation of fresh plants by microorganisms, mainly bacteria and fungi. The appropriate selection of plants, microorganism strains, and conditions under which the fermentation process is carried out is very important in terms of obtaining a suitable matrix of biologically active compounds with different biological properties. The purpose of this review is to provide verified data on the current knowledge acquired regarding the biological activity of FPEs for cosmetic use and dermal applications. The antioxidant, antimicrobial, anti-inflammatory, anti-melanogenic, and wound-healing activity of FPEs, as well as their potential dermal applications, will be described.

COVID-19 and primary wound healing: A new insights and advance

With the outbreak and pandemic of coronavirus disease-2019 (COVID-19), a huge number of people died of it. Apart from lung injuries, multiple organs have been confirmed to be impaired. In COVID-19 time, primary wound healing processes always prolong, however, its possible underlying mechanisms are still unclear. Therefore, to overcome this clinical problem, clarifying its underlying mechanisms clearly is necessary and urgently needed. In this review, we summarized that COVID-19 can prolong primary wound healing by inducing excessive inflammation and oxidative stress, disturbing immune system and haematological system, as well as influencing the functions and viability of epidermal stem cells (ESCs). Otherwise, we summarized that the strict control measures of blocking up COVID-19 pandemic can also have side effects on primary wound healing process.

Epimorphic regeneration in the mammalian tympanic membrane

Adult mammals are generally believed to have limited ability to regenerate complex tissues and instead, repair wounds by forming scars. In humans and across mammalian species, the tympanic membrane (TM) rapidly repairs perforations without intervention. Using mouse models, we demonstrate that the TM repairs itself through a process that bears many hallmarks of epimorphic regeneration rather than typical wound healing. Following injury, the TM forms a wound epidermis characterized by EGFR ligand expression and signaling. After the expansion of the wound epidermis that emerges from known stem cell regions of the TM, a multi-lineage blastema-like cellular mass is recruited. After two weeks, the tissue architecture of the TM is largely restored, but with disorganized collagen. In the months that follow, the organized and patterned collagen framework of the TM is restored resulting in scar-free repair. Finally, we demonstrate that deletion of Egfr in the epidermis results in failure to expand the wound epidermis, recruit the blastema-like cells, and regenerate normal TM structure. This work establishes the TM as a model of mammalian complex tissue regeneration.

Vascular Endothelial Growth Factor Supplementation Enhance Skin Antioxidant Capacity in Hyperglycemic Rats

The fundamental reasons for delayed wound healing in diabetic animals include inadequate production of growth factors or their increased devastation. Vascular Growth Factor (VEGF) has a biological role in the healing process of mucosal and skin wounds, especially in the process of new vessel formation. We planned to examine the oxidant-antioxidant events that occur during healing with topical VEGF application in diabetic rats. Experiments were performed 36 adults female Wistar albino rat diabetes induced by streptozotocin. The incisional wounds were made on the dorsal region in the rats. Rats were separated to 3 groups: the untreated (negative control) group (n=12), the chitosan group (n=12), the chitosan + VEGF group (n=12). The treatments were continued for 3 and 7 days, excluding the control and negative control groups. Then, the animals were sacrificed on the 3rd and 7th days of wound healing. Antioxidant and oxidant parameters in skin tissue were measured using biochemical methods. Topical VEGF application was decreased the NOx levels on the 3rd day compared to other groups. Moreover, it increased wound tissue GSH and AA levels, subsequently contributing to the enhance tissue antioxidant capacity. In conclusion, VEGF application increases the antioxidant capacity of the tissue and simultaneously reduces the oxidative stress and thus gives a positive acceleration to the wound healing process.

Mesenchymal stem cell-derived extracellular vesicles in skin wound healing: roles, opportunities and challenges

Skin wounds are characterized by injury to the skin due to trauma, tearing, cuts, or contusions. As such injuries are common to all human groups, they may at times represent a serious socioeconomic burden. Currently, increasing numbers of studies have focused on the role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in skin wound repair. As a cell-free therapy, MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy. Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures, including the regeneration of vessels, nerves, and hair follicles. In addition, MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization, wound angiogenesis, cell proliferation, and cell migration, and by inhibiting excessive extracellular matrix production. Additionally, these structures can serve as a scaffold for components used in wound repair, and they can be developed into bioengineered EVs to support trauma repair. Through the formulation of standardized culture, isolation, purification, and drug delivery strategies, exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair. In conclusion, MSC-derived EVs-based therapies have important application prospects in wound repair. Here we provide a comprehensive overview of their current status, application potential, and associated drawbacks.

Treatment and Improvement of Healing after Surgical Intervention

The development of abnormal scars has a great impact on people's well-being, and improving scarring outcomes after surgery is a field that currently lacks consensus. This review aims to identify newly researched approaches to improving the quality of surgical scars. A systematic search of PubMed, Scopus, Web of Science, and ScienceDirect was conducted between 13 May 2023 and 17 May 2023, in accordance with the recommendations of the PRISMA Statement. Study selection and analysis of methodological quality were performed in parts, independently and blindly, based on eligibility criteria. The 21 prospective, comparative, and randomized studies reviewed included 1057 subjects and studied approaches such as topical applications of creams with herbal extracts and silicone gels, growth factors, negative pressure dressings, oligonucleotides, intralesional injection of compounds such as botulinum toxin, skin closure techniques such as suturing and tissue adhesive, and laser treatments. There are recent research techniques that generate good results and are really promising to improve the results of surgical scars; however, the available evidence is extremely limited in some cases, and it is necessary to deepen its analysis to obtain reliable action protocols in each type of surgery.

Research progress and insights on the role of ferroptosis in wound healing

Ferroptosis is a newly discovered cell death type which is different from apoptosis, autophagy, pyroptosis as well as necrosis in the following aspects: morphology, biochemistry, gene and regulatory mechanisms. Ferroptosis is regulated by multiples of mechanisms such as system Xc- mechanism, glutathione peroxidase 4 (GPX4) mechanism, iron metabolism and lipid metabolism. Currently, ferroptosis has been revealed to be significant in wound healing such as diabetic wound, irradiated wound and ultraviolet (UV)-driven wound. Hence, how to intervene in the pathogenesis as well as the development of wounds and promote the wound healing by the regulation of ferroptosis have become a research hotspot. This review systematically summarises the latest scientific advances of ferroptosis and wound healing fields, with hoping to propose a new insight and advance in the wound treatment.

EHO-85, Novel Amorphous Antioxidant Hydrogel, Containing Olea europaea Leaf Extract-Rheological Properties, and Superiority over a Standard Hydrogel in Accelerating Early Wound Healing: A Randomized Controlled Trial

Many advanced wound healing dressings exist, but there is little high-quality evidence to support them. To determine the performance of a novel amorphous hydrogel (EHO-85) in relation to its application, we compared its rheological properties with those of other standard hydrogels (SH), and we assessed the induction of acceleration of the early stages of wound healing as a secondary objective of a prospective, multicenter, randomized, observer-blinded, controlled trial. The patients were recruited if they had pressure, venous, or diabetic foot ulcers and were treated with EHO-85 (n = 103) or VariHesive^® (SH) (n = 92), and their response was assessed by intention-to-treat as wound area reduction (WAR (%)) and healing rate (HR mm²/day) in the second and fourth weeks of treatment. Results: EHO-85 had the highest shear thinning and G'/G″ ratio, the lowest viscous modulus, G″, and relatively low cohesive energy; EHO-85 had a significantly superior effect over SH in WAR and HR, accelerating wound healing in the second and fourth weeks of application (p: 0.002). This superiority is likely based on its optimal moisturizing capacity and excellent pH-lowering and antioxidant properties. In addition, the distinct shear thinning of EHO-85 facilitates spreading by gentle hand pressure, making it easier to apply to wounds. These rheological properties contribute to its improved performance.

Rosmarinic Acid-Grafted Dextran/Gelatin Hydrogel as a Wound Dressing with Improved Properties: Strong Tissue Adhesion, Antibacterial, Antioxidant and Anti-Inflammatory

Designing a strong tissue adhesive and multifunctional hydrogel dressing for various skin injuries is still a significant challenge. Based on the bioactive activities of rosmarinic acid (RA) and its catechol structure being similar to dopamine, RA-grafted dextran/gelatin hydrogel (ODex-AG-RA) was designed and systemically characterized in this study. The ODex-AG-RA hydrogel exhibited excellent physicochemical properties, including fast gelation time (61.6 ± 2.8 s), strong adhesive strength (27.30 ± 2.02 kPa) and enhanced mechanical properties (1.31 × 10⁴ Pa of G'). The examination of hemolysis and co-culturing with L929 cells showed the strong in vitro biocompatibility of ODex-AG-RA hydrogels. The ODex-AG-RA hydrogels exhibited a 100% mortality rate against S. aureus and at least 89.7% against E. coli in vitro. In vivo evaluation for efficacy in skin wound healing was carried out in a rat model of full-thickness skindefect. The amount of collagen deposition and CD31 on wounds in the two ODex-AG-RA-1 groups on day 14 was 4.3 times and 2.3 times of that in the control group, respectively. Furthermore, the mechanism of ODex-AG-RA-1 for promoting wound healing was proved to be related to its anti-inflammatory properties by adjusting the expression of inflammatory cytokines (TNF-α and CD163) and reducing the level of oxidative stress (MDA and H₂O₂). Overall, this study demonstrated the wound-healing efficacy of RA-grafted hydrogels for the first time. ODex-AG-RA-1 hydrogel, due to its adhesive, anti-inflammatory, antibacterial and antioxidative activities, was a promising candidate as a wound dressing.

Reducing Risks for Poor Surgical Wound Healing

This review summarizes common risk factors for poor surgical healing on the face and neck and a generalized approach to treating a delayed healing wound. During the preoperative evaluation patients should be screened for prior irradiation, cigarette or e-cigarette use, chronic steroid use, alcoholism, diabetes, malnutrition, and other chronic medical conditions and medications. Despite the surgeon's best efforts to prevent poor surgical healing, some wounds may display signs of persistent inflammation. The facial plastic surgeon should be astute in recognizing delayed healing and identifying intrinsic and extrinsic risk factors so that timely intervention can be performed.

The Rhytidectomy Scar: Analysis of Patient and Surgeon Perspectives

An understanding of patient preference is vital for surgeons to create outcomes that align with the goals of patients undergoing cosmetic surgery. This study analyzes the perception of the rhytidectomy scar from the perspective of cosmetic patients and surgeons. Cross-sectional surveys were administered in-person to cosmetic patients and online to facial plastic and reconstructive surgeons in the United States. Participants were presented with standardized lateral view photographs of preauricular scars for 10 patients at least 12 months post rhytidectomy procedure. A variety of rhytidectomy incisions were chosen to include pre- versus post-tragal incisions, blunted hair tuft, hypopigmentation, narrow versus wide scar healing. Participants were asked to rate the outcome of the preauricular rhytidectomy scar using the Likert scale from 1 to 10. Quantitative analysis indicates that while both surgeons and cosmetic patients viewed hypopigmented scars less favorably, surgeons were more concerned with pre-tragal incision and blunted hair tuft. Furthermore, the number of rhytidectomies performed by surgeons resulted in more critical analysis of the scars presented in this study. Qualitative analysis of the frequent use of "natural" in the patient comments suggests the importance of maintaining a sense of "normalcy" as well. In contrast, the surgeon comments are most frequently about the relationship between the scar and surrounding anatomical structures, suggesting a descriptive focus on the technicality of scar placement and subsequent anatomical result. Cosmetic patients are primarily concerned about scar appearance while surgeons are more focused on the technical orientation of the scar. An understanding and comparison of the language and perceptions of surgeons and cosmetic patients regarding rhytidectomy scars are vital in creating aesthetic results and managing patient expectations.

Impact of pre-diabetes, well-controlled diabetes, and poorly controlled diabetes on anastomotic leakage after esophagectomy for esophageal cancer: a two-center retrospective cohort study of 1901 patients

BACKGROUND

Diabetes is known to be associated with anastomotic leakage (AL) after esophagectomy. However, it is unknown whether well-controlled diabetes is also associated with AL.

METHODS

We conducted a two-center retrospective cohort database study of patients who underwent oncological esophagectomy (2011-2019). Patients were divided into four groups: normoglycemia, pre-diabetes, well-controlled diabetes (hemoglobin A1c [HbA1c] < 7.0%), and poorly controlled diabetes (HbA1c ≥ 7.0%). The occurrence of AL and length of stay were compared between groups using multivariable analyses. The relationship between categorical HbA1c levels and AL was also investigated in patients stratified by diabetes medication before admission.

RESULTS

Among 1901 patients, 1114 (58.6%) had normoglycemia, 480 (25.2%) had pre-diabetes, 180 (9.5%) had well-controlled diabetes, and 127 (6.7%) had poorly controlled diabetes. AL occurred in 279 (14.7%) patients. Compared with normoglycemia, AL was significantly associated with both well-controlled diabetes (odds ratio 1.83, 95% confidence interval [CI] 1.22-2.74) and poorly controlled diabetes (odds ratio 1.95, 95% CI 1.23-3.09), but not with pre-diabetes. Preoperative HbA1c levels showed a J-shaped association with AL in patients without diabetes medication, but no association in patients with diabetes medication. Compared with normoglycemia, only poorly controlled diabetes was significantly associated with longer hospital stay after surgery, especially in patients with operative morbidity (unstandardized coefficient 14.9 days, 95% CI 5.6-24.1).

CONCLUSIONS

Diabetes was associated with AL after esophagectomy even in well-controlled patients, but pre-diabetes was not associated with AL. Operative morbidity, including AL, in poorly controlled diabetes resulted in prolonged hospital stays compared with normoglycemia.

A Novel Punch Technique for Facial Pigmented Melanocytic Nevus

The punch tool is a swift and practical instrument in the facial pigmented melanocytic nevus. However, few studies have evaluated the efficacy of the method for facial pigmented nevus. The aim of this study was to evaluate the practicability and effectiveness of removing facial pigmented nevus by punch biopsy technique. This was an observational study of patients with facial pigmented nevus in the Hospital of Plastic Surgery, Weifang Medical University. The ages of patients ranged from 15 to 36 years (average, 25 y). The outcome evaluations included Vancouver Scar Scale (VSS) score, esthetic appearance, and patient satisfaction. Following standard procedures, preoperative surgical excision was performed with safety margins. Anatomopathologic analysis of the surgical specimen was used as the gold standard to evaluate the accuracy of diagnosis by punch biopsy. From January 2019 to January 2020, this punch technique was carried out on 96 patients (151 pigmented nevus) with 35 melanocytic nevus on the forehead, 39 on the cheek, 21 on the eyelid, and 45 on the nose, whereas 11 were on nasolabial folds. The diameters of pigmented nevus are 0.5 to 10 mm on the face. All patients were evaluated at a follow-up visit ranging from 6 to 20 months (average, 11±1.5 mo) and healed with no complication. The histopathological examinations of the skin lesions showed benign outcomes. The mean Vancouver Scar Scale were 1.1±0.4. Ideal cosmetic and functional outcomes were achieved in 94 patients (97.9%). All patients achieved complete satisfaction except 2 patients with partial satisfaction. No recurrences and complications were recorded. This study demonstrated that the punch technique is an effective method to remove facial pigmented melanocytic nevus with acceptable functional and esthetic outcomes without relapse.

Wound Healing after Acellular Dermal Substitute Positioning in Dermato-Oncological Surgery: A Prospective Comparative Study

BACKGROUND

MatriDerm and Integra are both widely used collagenic acellular dermal matrices (ADMs) in the surgical setting, with similar characteristics in terms of healing time and clinical indication. The aim of the present study is to compare the two ADMs in terms of clinical and histological results in the setting of dermato-oncological surgery.

METHODS

Ten consecutive patients with medical indications to undergo surgical excision of skin cancers were treated with a 2-step procedure at our Dermatologic Surgery Unit. Immediately after tumor removal, both ADMs were positioned on the wound bed, one adjacent to the other. Closure through split-thickness skin grafting was performed after approximately 3 weeks. Conventional histology, immunostaining and ELISA assay were performed on cutaneous samples at different timepoints.

RESULTS

No significant differences were detected in terms of either final clinical outcomes or in extracellular matrix content of the neoformed dermis. However, Matriderm was observed to induce scar retraction more frequently. In contrast, Integra was shown to carry higher infectious risk and to be more slowly reabsorbed into the wound bed. Sometimes foreign body-like granulomatous reactions were also observed, especially in Integra samples.

CONCLUSIONS

Even in the presence of subtle differences between the ADMs, comparable global outcomes were demonstrated after dermato-oncological surgery.

Adipose-derived stem cells applied in skin diseases, wound healing and skin defects: a review

Adipose tissue presents a comparably easy source for obtaining stem cells, and more studies are increasingly investigating the therapeutic potential of adipose-derived stem cells. Wound healing, especially in chronic wounds, and treatment of skin diseases are some of the fields investigated. In this narrative review, the authors give an overview of some of the latest studies concerning wound healing as well as treatment of several skin diseases and concentrate on the different forms of application of adipose-derived stem cells.

An Effective Peptide-Based Platform for Efficient Exosomal Loading and Cellular Delivery of a microRNA

Exosomes, membrane-bound nanosized vesicles of biologic origin, are known to contain various molecules, e.g., proteins, lipids, and nucleic acids, which contribute to the exosomes' ability to mediate cell-to-cell communication. Recent impediments of artificial nanoparticles in drug delivery, including low cellular uptake, activation of the immune system, and tissue obstacles, have led scientists to engineer exosomes as drug delivery vehicles. Though exosomes possess inherent properties of stability, biocompatibility, low immunogenicity, and capability to cross biological barriers, there is a need to develop technologies that allow the efficient loading of therapeutic materials into exosomes. Here, we introduced a simple peptide-equipped technology that can enhance the cargo-loading potential of exosomes in a mild loading environment. Specifically, a known cell-penetrating peptide, YARA, derived from human immunodeficiency virus-1 trans-activator of transcription, was covalently conjugated with miR-21-5p, a mammalian microRNA. The conjugate YARA-miR-21-5p was then incubated with exosomes, isolated from either mesenchymal stem cells or cancer cells, for loading. Exosomal loading of YARA-miR-21-5p was time-dependent and demonstrated an impressive 18.6-fold increase in efficiency over exosomal loading of miR-21-5p through incubation. After effective cellular uptake, the loaded exosomes rapidly delivered YARA-miR-21-5p into mammalian cells. Relative to unloaded exosomes and free YARA-miR-21-5p, the loaded exosomes significantly enhanced the proliferation, migration, and invasion of human and mouse fibroblasts, which are vital steps in wound healing. This study lays the groundwork for using cell-penetrating peptides as an innovative approach to efficiently load therapeutic cargos, e.g., microRNAs, into exosomes, which can then be employed to deliver the cargos into cells to yield biological effects.

Topical Hyperbaric Oxygen Therapy Versus Local Ozone Therapy in Healing of Venous Leg Ulcers

BACKGROUND

the treatment of venous leg ulcers still poses a difficult interdisciplinary medical problem. The aim of this study was to compare the therapeutic efficacy of local hyperbaric oxygen therapy with local ozone therapy in the treatment of venous leg ulcers.

MATERIALS

this study included 114 patients; 60 males (52.63%) and 54 females (47.36%) of ages ranging between 39 and 88 years (mean age: 68.9 ± 9.8 years) with venous leg ulcers, who underwent topical hyperbaric oxygen therapy (group I) and local ozone therapy (group II). In each of the study groups, the patients underwent 30 therapeutic procedures lasting 30 min each. The progress in wound healing was evaluated by computerized planimetry, and the intensity of pain was assessed with the use of the Visual Analogue Scale (VAS).

RESULTS

in both groups of treated patients, a statistically significant (p = 0.000001) reduction in the area of treated ulcers was achieved. In group I, the wound area decreased by an average of 69.67 ± 22.52%, from 7.55 ± 2.99 cm² to 2.78 ± 2.43 cm², and in group II, by an average of 41.33 ± 21.31%, from 7.36 ± 2.82 cm² to 4.62 ± 2.76 cm². In both groups of patients, a statistically significant (p = 0.000001) reduction in the intensity of pain ailments was observed: in group I, by an average of 0.55 ± 0.54 points, and in group II, by an average of 2.33 ± 0.82 points on the VAS scale.

CONCLUSIONS

local hyperbaric oxygen therapy and local ozone therapy cause a statistically significant reduction in the surface area of venous leg ulcers as well as in the intensity of pain. Better results were observed after the application of local hyperbaric oxygen therapy procedures.

Herbal Products and Their Active Constituents for Diabetic Wound Healing-Preclinical and Clinical Studies: A Systematic Review

The purpose of this review is to provide verified data on the current knowledge acquired in preclinical and clinical studies regarding topically used herbal products and their active constituents (formulations and dressings) with diabetic wound healing activity. Moreover, herbal products and their active constituents used for diabetic wound infections, and various cellular and molecular mechanisms of their actions will also be described. The electronic databases were searched for articles published from 2012 to 2022. Publications with oral or systemic administration of herbal products in diabetic wound healing, published before 2012, available only as an abstract, or in languages other than English were excluded from the study. The 59 articles comparing topically used herbal products in diabetic wound healing treatment versus control treatments (placebo or active therapy) were selected. Herbal products through different mechanisms of action, including antimicrobial, anti-inflammatory, antioxidant activity, stimulation of angiogenesis, production of cytokines and growth factors, keratinocytes, and fibroblast migration and proliferation may be considered as an important support during conventional therapy or even as a substitute for synthetic drugs used for diabetic wound treatment.

Wound Healing Properties of Natural Products: Mechanisms of Action

A wound is the loss of the normal integrity, structure, and functions of the skin due to a physical, chemical, or mechanical agent. Wound repair consists of an orderly and complex process divided into four phases: coagulation, inflammation, proliferation, and remodeling. The potential of natural products in the treatment of wounds has been reported in numerous studies, emphasizing those with antioxidant, anti-inflammatory, and antimicrobial properties, e.g., alkaloids, saponins, terpenes, essential oils, and polyphenols from different plant sources, since these compounds can interact in the various stages of the wound healing process. This review addresses the most current in vitro and in vivo studies on the wound healing potential of natural products, as well as the main mechanisms involved in this activity. We observed sufficient evidence of the activity of these compounds in the treatment of wounds; however, we also found that there is no consensus on the effective concentrations in which the natural products exert this activity. For this reason, it is important to work on establishing optimal treatment doses, as well as an appropriate route of administration. In addition, more research should be carried out to discover the possible side effects and the behavior of natural products in clinical trials.

Referral and Management of Pretibial Lacerations in Two District General Hospitals

Background Pretibial lacerations are common injuries that have a significant yet underestimated association with morbidity and mortality. Although they may occur in any age group, they are commonly followed by an often relatively minor trauma in elderly and frail patients. The six-month mortality among such patients may be more than double the age group average. Currently, 5.2 in 1000 patients per year present to the emergency departments in UK hospitals due to pretibial lacerations. The associated acute admissions have a high financial cost. Despite the significant disease burden, there is a paucity of evidence on the optimal management of such injuries. This study aimed to describe the typical demographic and injury factors of individuals presenting to two district general hospitals, as well as their subsequent management and referral. Methodology Relevant patients were identified through NHS coding searches. Subsequently, it was found that 99 patients presented to an NHS trust with pretibial lacerations throughout 2020. A retrospective manual evaluation of clinical documentation was performed to identify the details of the patients' injury, management, referral, and demographics. Results The patients had a mean age of 55.4 (SD 28.3), and 56.6% were female. The most commonly presenting mechanism of injury was direct blunt trauma. The majority of cases were solely managed and discharged directly by the emergency department (74.8%). Of the 99 patients, 25 (25.3%) were referred to specialist services, 12 (12.1%) were managed conservatively, and 13 (13.1%) underwent operative intervention. The mean length of stay for those referred was 5.9 days, and the mean for the same was greater for those managed conservatively compared to those managed operatively (9.0 vs. 2.6 days). Among patients discharged by the emergency department, the most common method of wound closure was steristrips (n = 40; 54.1%), followed by conservative management with dressings (n = 22; 29.7%), sutures (n = 10, 13.5%) and glue (n = 5; 6.8%). Conclusions Overall, this study showed that the majority of patients presenting with pretibial lacerations have minor wounds that can be effectively managed in the emergency department. However, those with considerably more injuries should be provided an early referral to specialist services, where they would ideally receive early surgery and comprehensive follow-up.

Porcine Acellular Dermal Matrix Promotes Migration and Suppresses Inflammation of Keratinocytes by Mediating the AKT Signaling Pathway

Porcine acellular dermal matrix (pADM) is known to accelerate wound healing. However, the underlying molecular mechanism remains unclear. This study aimed to investigate the effects of pADM on wound healing and its underlying mechanisms. HaCaT cells were treated with hydrogen peroxide (H2O2) or pADM, and the appropriate treatment concentration was determined using the cell counting kit-8 and flow cytometry. Cell migration was assessed using a Transwell assay and scratch test. Inflammation was evaluated using enzyme-linked immunosorbent assay. Western blotting was performed to measure the levels of protein kinase B (AKT) pathway-related proteins. The results showed that H2O2 inhibited cell viability and induced apoptosis in a dose-dependent manner. pADM promoted cell migration and decreased the levels of interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) in H2O2-treated HaCaT cells. Moreover, pADM rescued the downregulation of phosphorylated (p)-AKT and p-mechanistic target of rapamycin (mTOR) induced by H2O2. LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, abrogated migration and anti-inflammatory response caused by pADM. In conclusion, pADM promotes cell migration and inhibits inflammation by activating the AKT pathway under oxidative stress. These findings support the use of pADM for post-traumatic therapy and reveal a novel underlying mechanism of action.

Native and engineered extracellular vesicles for wound healing

Extracellular vesicles (EVs) that act as messengers mediate communication between parent and recipient cells through their contents, including nucleic acids, proteins, and lipids. These endogenous vesicles have emerged as a novel cell-free strategy for the treatment of diseases. EVs can be released by various types of cells with unique biological properties. Recent studies have shown that native EVs are used as therapeutic agents to promote tissue repair by delivering various growth factors and trophic factors including VEGF, EGF, TFN-α, IL-1β, and TGF-β to participate in all physiological processes of wound healing. Furthermore, to improve their specificity, safety, and efficiency for wound healing, the content and surface of EVs can be designed, modified, and engineered. The engineering strategies of EVs are divided into parent cell modification and indirect modification of EVs. The therapeutic potential of current EVs and engineered EVs for wound healing still requires the exploration of their large-scale clinical applications through innovative approaches. Herein, we provide an overview of the current biological knowledge about wound healing and EVs, as well as the application of native EVs in promoting wound healing. We also outline recent advances in engineering EV methodologies to achieve ideal therapeutic potential. Finally, the therapeutic applications of engineered EVs in wound healing are reviewed, and the challenges and prospects for the translation of engineered EVs to clinical applications are discussed.

Inhibition of TGFβ1/Smad pathway by NF-κB induces inflammation leading to poor wound healing in high glucose

This study mainly analyzed the relationship between nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transforming growth factor-β (TGFβ1)/Smad under high glucose environment and its influence on wound healing. Fibroblast NIH-3T3 was used to analyze the effect of high concentration glucose (20 nmol/mL) on cell viability, migration ability, inflammation level and NF-κB pathway. Pyrrolidinedithiocarbamate (PDTC) was used to inhibit NF-κB for rescue experiments. Diabetic mice were used to construct wound healing models. Recombinant TGF-β1 was used to promote wound healing in diabetic mice. FSL-1 was applied to activate NF-κB to verify the mechanism. High glucose inhibited cell viability and migration ability, promoted the expression of TNF-α, IL-6 and IL-1β, induced the activation of NF-κB pathway in fibroblasts. Inhibition of NF-κB not only blocked the decrease in cell viability and migration ability induced by high glucose, but also relieved the release of inflammatory factors. TGF-β1 activated the TGF-β1/Smad pathway and promoted wound healing in diabetic mice. Activating the NF-κB pathway not only inhibited the activation of the TGF-β1/Smad pathway, but also alleviated the promoting effect of TGF-β1 on wound healing. In a high glucose environment, the activation of NF-κB may inhibit the function of fibroblasts by inhibiting the TGF-β1/Smad pathway, resulting in poor wound healing.

Investigation on wound healing effect of Mediterranean medicinal plants and some related phenolic compounds: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The human skin constitutes a biological barrier against external stress and wounds can reduce the role of its physiological structure. In medical sciences, wounds are considered a major problem that requires urgent intervention. For centuries, medicinal plants have been used in the Mediterranean countries for many purposes and against wounds.

AIM OF THIS REVIEW

Provides an outlook on the Mediterranean medicinal plants used in wound healing. Furthermore, the wound healing effect of polyphenolic compounds and their chemical structures are also summarized. Moreover, we discussed the wound healing process, the structure of the skin, and the current therapies in wound healing.

MATERIALS AND METHODS

The search was performed in several databases such as ScienceDirect, PubMed, Google Scholar, Scopus, and Web of Science. The following Keywords were used individually and/or in combination: the Mediterranean, wound healing, medicinal plants, phenolic compounds, composition, flavonoid, tannin.

RESULTS

The wound healing process is distinguished by four phases, which are respectively, hemostasis, inflammation, proliferation, and remodeling. The Mediterranean medicinal plants are widely used in the treatment of wounds. The finding showed that eighty-nine species belonging to forty families were evaluated for their wound-healing effect in this area. The Asteraceae family was the most reported family with 12 species followed by Lamiaceae (11 species). Tunisia, Egypt, Morocco, and Algeria were the countries where these plants are frequently used in wound healing. In addition to medicinal plants, results showed that nineteen phenolic compounds from different classes are used in wound treatment. Tyrosol, hydroxytyrosol, curcumin, luteolin, chrysin, rutin, kaempferol, quercetin, icariin, morin, epigallocatechin gallate, taxifolin, silymarin, hesperidin, naringin, isoliquiritin, puerarin, genistein, and daidzein were the main compounds that showed wound-healing effect.

CONCLUSION

In conclusion, medicinal plants and polyphenolic compounds provide therapeutic evidence in wound healing and for the development of new drugs in this field.

Perioperative considerations for cancer patients with obesity: A narrative review

Cancer in patients with obesity has become increasingly common throughout much of the world. Based on our experiences in a specialized cancer center, we have developed a set of standards and expectations that should streamline the surgical journey for this patient population. These recommendations should inform the perioperative management of oncology patients with obesity and help raise awareness of this critical and under-discussed topic.

The Stimulation of Macrophages by Systematical Administration of GM-CSF Can Accelerate Adult Wound Healing Process

Skin wound repair remains a major challenge in clinical care, and various strategies have been employed to improve the repair process. Recently, it has been reported that macrophages are important for the regeneration of various tissues and organs. However, their influence on wound repair is unclear. Here, we aimed to explore whether macrophages would participate in the wound healing process and to explore new possibilities of treatment for skin defects. We firstly created a mouse full-thickness skin defect model to observe the distribution of macrophages in the regenerating tissue and then detected the influence of macrophages on skin defect repair in both macrophage-depletion and macrophage-mobilization models. We found that the number of macrophages increased significantly after skin defect and persisted during the process of wound repair. The regeneration process was significantly prolonged in macrophage-depleted animals. RT-qPCR and ELISA assays further demonstrated that the expression of growth factors was perturbed in the regenerating tissue. The activation of macrophages by granulocyte-macrophage colony-stimulating factor (GM-CSF) injection could significantly improve wound healing, accompanied with an upregulation of the expression of various growth factors. In conclusion, the current study demonstrated that macrophages are critical for skin regeneration and that GM-CSF exhibited therapeutic potential for wound healing.

Scarless wound healing: Current insights from the perspectives of TGF-β, KGF-1, and KGF-2

The process of wound healing involves a complex and vast interplay of growth factors and cytokines that coordinate the recruitment and interaction of various cell types. A series of events involving inflammation, proliferation, and remodeling eventually leads to the restoration of the damaged tissue. Abrogation in the regulation of these events has been shown to result in excessive scarring or non-healing wounds. While the process of wound healing is not fully elucidated, it has been documented that the early events of wound healing play a key role in the outcome of the wound. Furthermore, high levels of inflammation have been shown to lead to scarring. The regulation of these events may result in scarless wound healing, especially in adults. The inhibition of transforming growth factor-β (TGF-β) and the administration of keratinocyte growth factors (KGF), KGF-1 and KGF-2, has in recent years yielded positive results in the acceleration of wound closure and reduced scarring. Here, we encapsulate recent knowledge on the roles of TGF-β, KGF1, and KGF2 in wound healing and scar formation and highlight the areas that need further investigation. We also discuss potential future directions for the use of growth factors in wound management.

The potential application of natural products in cutaneous wound healing: A review of preclinical evidence

Under normal circumstances, wound healing can be summarized as three processes. These include inflammation, proliferation, and remodeling. The vast majority of wounds heal rapidly; however, a large percentage of nonhealing wounds have still not been studied significantly. The factors affecting wound nonhealing are complex and diverse, and identifying an effective solution from nature becomes a key goal of research. This study aimed to highlight and review the mechanisms and targets of natural products (NPs) for treating nonhealing wounds. The results of relevant studies have shown that the effects of NPs are associated with PI3K-AKT, P38MAPK, fibroblast growth factor, MAPK, and ERK signaling pathways and involve tumor growth factor (TNF), vascular endothelial growth factor, TNF-α, interleukin-1β, and expression of other cytokines and proteins. The 25 NPs that contribute to wound healing were systematically summarized by an inductive collation of the six major classes of compounds, including saponins, polyphenols, flavonoids, anthraquinones, polysaccharides, and others, which will further direct the attention to the active components of NPs and provide research ideas for further development of new products for wound healing.

Extracellular vesicles: Emerging frontiers in wound healing

Extracellular vesicles are membranous particles, ranging from 30 nm to 10 µm in diameter, which are released by nearly all cell types to aid in intercellular communication. These complex vesicles carry a multitude of signaling moieties from their cell of origin, such as proteins, lipids, cell surface receptors, enzymes, cytokines, metabolites, and nucleic acids. A growing body of evidence suggests that in addition to delivering cargos into target cells to facilitate intercellular communication, extracellular vesicles may also play roles in such processes as cell differentiation and proliferation, angiogenesis, stress response, and immune signaling. As these vesicles have natural biocompatibility, stability in circulation, low toxicity, and low immunogenicity, and serve as efficient carriers of molecular cargos, these nanoparticles are ideal therapeutic candidates for regenerative medicine. Exploring and identifying the homeostatic functions of extracellular vesicles may facilitate the development of new regenerative therapies. In this review, we summarize the wound healing process, difficulties in stem cell therapies for regenerative medicine, and the applications of mesenchymal stromal cell-derived extracellular vesicles in improving and accelerating the wound healing process.

TIP60 acts as a regulator of genes involved in filopodia formation and cell migration during wound healing

Wound healing is a complex phenomenon that requires coordination of numerous molecular and cellular changes to facilitate timely and efficient repair of the damaged tissue. Although many of these molecular pathways have been detailed, others remain to be elucidated. In the present work, we show for the first time, roles for the acetyltransferase TIP60 and nuclear receptor transcription factor PXR in this process, participating in wound healing by altering actin dynamics and cellular motility. We found that in response to wound-injury, TIP60 induces rapid formation of filopodia at the wounded cell front, leading to enhanced cell migration and faster closure of the wound. Further, qPCR analysis revealed heightened expression of Cdc42 and ROCK1 genes, key regulators involved in filopodia formation and actin reorganization, exclusively in TIP60-PXR-expressing cells upon wound-induction. We also performed ChIP assays to confirm the context-specific binding of TIP60 on the ROCK1 promoter and demonstrated that the TIP60 chromodomain is essential for loading of the TIP60–PXR complex onto the chromatin. Results from immunoprecipitation assays revealed that during the wounded condition, TIP60 alters the chromatin microenvironment by specifically acetylating histones H2B and H4, thereby modulating the expression of target genes. Overall, findings of this study show that TIP60 is a novel regulator of the wound healing process by regulating the expression of wound repair-related genes.

How Effective are Nano-Based Dressings in Diabetic Wound Healing? A Comprehensive Review of Literature

Chronic wound caused by diabetes is an important cause of disability and seriously affects the quality of life of patients. Therefore, it is of great clinical significance to develop a wound dressing that can accelerate the healing of diabetic wounds. Nanoparticles have great advantages in promoting diabetic wound healing due to their antibacterial properties, low cytotoxicity, good biocompatibility and drug delivery ability. Adding nanoparticles to the dressing matrix and using nanoparticles to deliver drugs and cytokines to promote wound healing has proven to be effective. This review will focus on the effects of diabetes on wound healing, introduce the properties, preparation methods and action mechanism of nanoparticles in wound healing, and describe the effects and application status of various nanoparticle-loaded dressings in diabetes-related chronic wound healing.

Pain Prevalence During Cancer Treatment: A Systematic Review and Meta-Analysis

CONTEXT

Pain is one of the most complex and prevalent symptoms in the cancer population. Despite the protective role of acute cancer-related pain, it is also an important predictor for the likelihood of developing chronic pain after cancer treatment.

OBJECTIVES

Since the last systematic review on pain prevalence rates during cancer treatment dates already from 2016, the aim of the present systematic review was to provide an overview of pain prevalence rates during cancer treatment since this previous review.

METHODS

A systematic search of the literature, including studies between 2014 and 2020, was conducted using the databases Pubmed, Embase, Scopus, Web of Science and Cochrane. Studies reporting pain prevalence rates during or within three months after curative cancer treatment was included. Title/abstract and full-text was screened double-blinded, followed by independent evaluation of the risk of bias. All prevalence rates were pooled within meta-analyses and a meta-regression was performed to clarify the amount of heterogeneity.

RESULTS

Of the 9052 studies, 12 studies were included in the meta-analysis of which 10 included breast cancer and two lung cancer patients. The pooled pain prevalence rate was 40% (95%CI 0.29-0.51), with a heterogeneity of 96%. Out of the meta-regression, only the covariate "method of pain measurement" significantly clarified the heterogeneity (P < 0.05), resulting in a residual heterogeneity of 94.88%.

CONCLUSION

Five years after the last systematic review published on this topic, pain is still very prevalent during cancer treatment. However, the pain prevalence rates were also very heterogeneous. These two findings emphasize the need for further research on the development of adequate pain assessment and pain management approaches during cancer treatment.

Reversibly immortalized keratinocytes (iKera) facilitate re-epithelization and skin wound healing: Potential applications in cell-based skin tissue engineering

Skin injury is repaired through a multi-phase wound healing process of tissue granulation and re-epithelialization. Any failure in the healing process may lead to chronic non-healing wounds or abnormal scar formation. Although significant progress has been made in developing novel scaffolds and/or cell-based therapeutic strategies to promote wound healing, effective management of large chronic skin wounds remains a clinical challenge. Keratinocytes are critical to re-epithelialization and wound healing. Here, we investigated whether exogenous keratinocytes, in combination with a citrate-based scaffold, enhanced skin wound healing. We first established reversibly immortalized mouse keratinocytes (iKera), and confirmed that the iKera cells expressed keratinocyte markers, and were responsive to UVB treatment, and were non-tumorigenic. In a proof-of-principle experiment, we demonstrated that iKera cells embedded in citrate-based scaffold PPCN provided more effective re-epithelialization and cutaneous wound healing than that of either PPCN or iKera cells alone, in a mouse skin wound model. Thus, these results demonstrate that iKera cells may serve as a valuable skin epithelial source when, combining with appropriate biocompatible scaffolds, to investigate cutaneous wound healing and skin regeneration.

Increased temperature at the healed area detected by thermography predicts recurrent pressure ulcers

Preventing recurrent pressure ulcers is an important challenge in healthcare. One of the reasons for the high rate of recurrent pressure ulcers is the lack of assessment methods for their early detection. Therefore, this study aimed to determine the thermographic characteristics of the healed area and to consider the predictive validity of thermographic images for recurrent pressure ulcers within a 2-week period. This observational study was conducted at a long-term care facility in Japan between July 2017 and February 2019 among patients whose pressure ulcers had healed. Thermographic images of the healed area were recorded once a week until recurrence or until the end of the study. We enrolled 30 participants, among whom 8 developed recurrent pressure ulcers. The generalised estimation equation revealed that the thermographic finding of increased temperature at the healed area compared to that of the surrounding skin was significantly associated with recurrent pressure ulcers (odds ratio: 101.13, 95% confidence interval: 3.60-2840.77, p = .007); the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for recurrent pressure ulcers within 2 weeks were 0.80, 0.94, 0.62, 0.97, 12.9 and 0.2, respectively. Our thermographic findings revealed that the temperature of the healed area was higher than that of the surrounding skin; this could be a useful predictor of pressure ulcer recurrence within 2 weeks, even in the absence of macroscopic changes.

The effects of electrical stimulation on diabetic ulcers of foot and lower limb: A systematic review

Diabetic foot ulcer (DFU) is a life-threatening condition affecting a third of diabetic patients. Many adjuvant therapies aimed at improving the healing rate (HR) and accelerating healing time are currently under investigation. Electrical stimulation (ES) is a physical-based therapy able to increase cells activity and migration into wound bed as well as inhibiting bacterial activity. The aim of this paper was to collect and analyse findings on the effects of ES used in combination with standard wound care (SWC) in the treatment of diabetic foot ulceration compared with SWC alone. A systematic review was performed to synthesise data from quantitative studies from eight databases. Article quality was assessed using the Crowe critical appraisal tool. Seven articles out of 560 publications met the inclusion criteria. A meta-analysis was not performed due to the heterogeneity of the studies and the results were narratively synthetised. Findings showed that HR appears to be higher among diabetic ulcers treated with ES; however, the reliability of these findings is affected by the small sample sizes of the studies. Furthermore, four studies are considered as moderate or high risk of bias. The evidence to suggest the systematic usage of ES in the treatment of DFUs is still insufficient.