Exploring the role of stem cells in cutaneous wound healing

miRNAs and their multifaceted role in cutaneous wound healing

The dynamic, complex process of cutaneous wound healing is required to restore skin integrity following an injury. This intricate process consists of four sequential and overlapping phases: hemostasis, inflammation, proliferation, and remodeling. Hemostasis immediately begins to function in response to vascular injury, forming a clot that stops the bleeding. To fight infection and remove debris, immune cells are enlisted during the inflammatory phase. Angiogenesis, re-epithelialization, and the creation of new tissue are all components of proliferation, whereas tissue maturation and scarring are the outcomes of remodeling. Chronic wounds, like those found in diabetic ulcers, frequently stay in a state of chronic inflammation because they are unable to go through these stages in a coordinated manner. The important regulatory roles that microRNAs (miRNAs) play in both normal and pathological wound healing have been highlighted by recent investigations. The miRNAs, small non-coding RNAs, modulate gene expression post-transcriptionally, profoundly impacting cellular functions. During the inflammatory phase, miRNAs control pro- and anti-inflammatory cytokines, as well as the activity of immune cells such as neutrophils and macrophages. Additionally, miRNAs are essential components of signaling networks related to inflammation, such as the toll-like receptor (TLR), nuclear factor kappa B (NF-kB), and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways. Some miRNAs have been discovered to either increase or alleviate inflammatory reactions, indicating their potential as therapeutic targets. Other miRNAs aid in angiogenesis by promoting the development of new blood vessels, which are essential for providing oxygen and nutrients to the healing tissue. They also affect keratinocyte migration and proliferation during the re-epithelialization phase, which involves growing new epithelial cells over the lesion. Another function of miRNAs is that they control the deposition of extracellular matrix (ECM) and the creation of scars during the remodeling phase. The abnormal expression of miRNAs in chronic wounds has led to the exploration of miRNA-based treatments. With a focus on resistant instances such as diabetic wounds, these therapeutic techniques seek to improve wound healing results by correcting the dysregulated miRNA expression.

Biological processes and factors involved in soft and hard tissue healing

Wound healing is a complex and iterative process involving myriad cellular and biologic processes that are highly regulated to allow satisfactory repair and regeneration of damaged tissues. This review is intended to be an introductory chapter in a volume focusing on the use of platelet concentrates for tissue regeneration. In order to fully appreciate the clinical utility of these preparations, a sound understanding of the processes and factors involved in soft and hard tissue healing. This encompasses an appreciation of the cellular and biological mediators of both soft and hard tissues in general as well as specific consideration of the periodontal tissues. In light of good advances in this basic knowledge, there have been improvements in clinical strategies and therapeutic management of wound repair and regeneration. The use of platelet concentrates for tissue regeneration offers one such strategy and is based on the principles of cellular and biologic principles of wound repair discussed in this review.

A multi-functional oxidative konjac glucomannan/ε-poly-l-lysine hydrogel with antibacterial, haemostatic, and chronic diabetic wound-treating properties

A chronic diabetic wound, one of the most severe complications of diabetes, has a high incidence and causes great pain to patients, threatening their lives. In this paper, oxidative konjac glucomannan (OKGM) was reacted with ε-poly-l-lysine (EPL) through the dynamic Schiff's base reaction to make a multi-functional hydrogel. This hydrogel had excellent mechanical properties, injectability, self-healing ability, adhesivity and cytocompatibility. The outstanding haemostatic property was also expressed in rat liver incision, liver injury and tail truncation models. In addition, this hydrogel exhibited unique antibacterial ability against the Gram-positive Staphylococcus aureus (S. aureus), the Gram-negative Escherichia coli (E. coli) and the Gram-negative Pseudomonas aeruginosa (P. aeruginosa). It also promoted wound healing, enhanced angiogenesis and regulated macrophage polarisation in the whole-layer rat diabetic wound model. The multi-functional hydrogel is a dressing with huge potential and prospects in chronic diabetic wound healing.

Pyroligneous extract, a biomaterial derived from pyrolytic palm kernel shell wood vinegar, as a novel diabetic wound healing aid: an animal study

OBJECTIVE

Wound in diabetes is difficult to heal since it possesses excessive inflammation. The aim of the study was to evaluate wound healing activity of chitosan-based hydrogel containing pyroligneous acid in diabetic animals.

SIGNIFICANCE

Pyroligneous acid, a byproduct of biochar production from palm kernel shell biomass, contained oxygenated compounds which, with extracting enrichment, could promote wound healing.

METHODS

Streptozotocin-induced diabetic male jcl: ICR mice were subjected to create wounds and treat with hydrogel containing pyroligneous extract at dose strengths of 0 (placebo), 100 and 150 µg/g-gel. Commercial gel (Intrasite®) was used as an active comparator. On 3-, 7-, 10- and 14-day post-wounding, wound contraction was rated and wound site tissues were collected. The specimens were H&E stained and microscopically examined to evaluate histological responses. The underline wound healing related cytokine and polypeptide expressions were determined using real-time PCR and western blot.

RESULTS

It was found that the extract accelerated the healing process in a dose-dependent manner where at dose strength of 150 µg/g-gel was as effective as active comparator. It increased gene expression of the cytokine and related proteins in TGF-β/SMAD signaling pathway and may further activate diabetic induced TGF-β downregulation to restore up to the level that healthy skin tissues express. It also enhanced the expressions of Akt, FAK, RhoA and Rac-1 and evidently activated phosphorylation of Akt and FAK.

CONCLUSION

The study demonstrated the extract could be a novel biomaterial for healing of such a chronic inflammatory wound as the wound in diabetes.

Molecular immunological mechanisms of impaired wound healing in diabetic foot ulcers (DFU), current therapeutic strategies and future directions

Diabetic foot ulcer (DFU) is a foremost cause of amputation in diabetic patients. Consequences of DFU include infections, decline in limb function, hospitalization, amputation, and in severe cases, death. Immune cells including macrophages, regulatory T cells, fibroblasts and other damage repair cells work in sync for effective healing and in establishment of a healthy skin barrier post-injury. Immune dysregulation during the healing of wounds can result in wound chronicity. Hyperglycemic conditions in diabetic patients influence the pathophysiology of wounds by disrupting the immune system as well as promoting neuropathy and ischemic conditions, making them difficult to heal. Chronic wound microenvironment is characterized by increased expression of matrix metalloproteinases, reactive oxygen species as well as pro-inflammatory cytokines, resulting in persistent inflammation and delayed healing. Novel treatment modalities including growth factor therapies, nano formulations, microRNA based treatments and skin grafting approaches have significantly augmented treatment efficiency, demonstrating creditable efficacy in clinical practices. Advancements in local treatments as well as invasive methodologies, for instance formulated wound dressings, stem cell applications and immunomodulatory therapies have been successful in targeting the complex pathophysiology of chronic wounds. This review focuses on elucidating the intricacies of emerging physical and non-physical therapeutic interventions, delving into the realm of advanced wound care and comprehensively summarizing efficacy of evidence-based therapies for DFU currently available.

Stem cell-based therapy for fibrotic diseases: mechanisms and pathways

Fibrosis is a pathological process, that could result in permanent scarring and impairment of the physiological function of the affected organ; this condition which is categorized under the term organ failure could affect various organs in different situations. The involvement of the major organs, such as the lungs, liver, kidney, heart, and skin, is associated with a high rate of morbidity and mortality across the world. Fibrotic disorders encompass a broad range of complications and could be traced to various illnesses and impairments; these could range from simple skin scars with beauty issues to severe rheumatologic or inflammatory disorders such as systemic sclerosis as well as idiopathic pulmonary fibrosis. Besides, the overactivation of immune responses during any inflammatory condition causing tissue damage could contribute to the pathogenic fibrotic events accompanying the healing response; for instance, the inflammation resulting from tissue engraftment could cause the formation of fibrotic scars in the grafted tissue, even in cases where the immune system deals with hard to clear infections, fibrotic scars could follow and cause severe adverse effects. A good example of such a complication is post-Covid19 lung fibrosis which could impair the life of the affected individuals with extensive lung involvement. However, effective therapies that halt or slow down the progression of fibrosis are missing in the current clinical settings. Considering the immunomodulatory and regenerative potential of distinct stem cell types, their application as an anti-fibrotic agent, capable of attenuating tissue fibrosis has been investigated by many researchers. Although the majority of the studies addressing the anti-fibrotic effects of stem cells indicated their potent capabilities, the underlying mechanisms, and pathways by which these cells could impact fibrotic processes remain poorly understood. Here, we first, review the properties of various stem cell types utilized so far as anti-fibrotic treatments and discuss the challenges and limitations associated with their applications in clinical settings; then, we will summarize the general and organ-specific mechanisms and pathways contributing to tissue fibrosis; finally, we will describe the mechanisms and pathways considered to be employed by distinct stem cell types for exerting anti-fibrotic events.

Insights into the role of adipose-derived stem cells and secretome: potential biology and clinical applications in hypertrophic scarring

Scar tissue is the inevitable result of repairing human skin after it has been subjected to external destructive stimuli. It leads to localized damage to the appearance of the skin, accompanied by symptoms such as itching and pain, which reduces the quality of life of the patient and causes serious medical burdens. With the continuous development of economy and society, there is an increasing demand for beauty. People are looking forward to a safer and more effective method to eliminate pathological scarring. In recent years, adipose-derived stem cells (ADSCs) have received increasing attention from researchers. It can effectively improve pathological scarring by mediating inflammation, regulating fibroblast proliferation and activation, and vascular reconstruction. This review focuses on the pathophysiological mechanisms of hypertrophic scarring, summarizing the therapeutic effects of in vitro, in vivo, and clinical studies on the therapeutic effects of ADSCs in the field of hypertrophic scarring prevention and treatment, the latest application techniques, such as cell-free therapies utilizing ADSCs, and discussing the advantages and limitations of ADSCs. Through this review, we hope to further understand the characterization of ADSC and clarify the effectiveness of its application in hypertrophic scarring treatment, so as to provide clinical guidance.

The Efficacy of Stem Cells in Wound Healing: A Systematic Review

Wound healing is an intricate process involving coordinated interactions among inflammatory cells, skin fibroblasts, keratinocytes, and endothelial cells. Successful tissue repair hinges on controlled inflammation, angiogenesis, and remodeling facilitated by the exchange of cytokines and growth factors. Comorbid conditions can disrupt this process, leading to significant morbidity and mortality. Stem cell therapy has emerged as a promising strategy for enhancing wound healing, utilizing cells from diverse sources such as endothelial progenitor cells, bone marrow, adipose tissue, dermal, and inducible pluripotent stem cells. In this systematic review, we comprehensively investigated stem cell therapies in chronic wounds, summarizing the clinical, translational, and primary literature. A systematic search across PubMed, Embase, Web of Science, Google Scholar, and Cochrane Library yielded 22,454 articles, reduced to 44 studies after rigorous screening. Notably, adipose tissue-derived mesenchymal stem cells (AD-MSCs) emerged as an optimal choice due to their abundant supply, easy isolation, ex vivo proliferative capacities, and pro-angiogenic factor secretion. AD-MSCs have shown efficacy in various conditions, including peripheral arterial disease, diabetic wounds, hypertensive ulcers, bullous diabeticorum, venous ulcers, and post-Mohs micrographic surgery wounds. Delivery methods varied, encompassing topical application, scaffold incorporation, combination with plasma-rich proteins, and atelocollagen administration. Integration with local wound care practices resulted in reduced pain, shorter healing times, and improved cosmesis. Stem cell transplantation represents a potential therapeutic avenue, as transplanted stem cells not only differentiate into diverse skin cell types but also release essential cytokines and growth factors, fostering increased angiogenesis. This approach holds promise for intractable wounds, particularly chronic lower-leg wounds, and as a post-Mohs micrographic surgery intervention for healing defects through secondary intention. The potential reduction in healthcare costs and enhancement of patient quality of life further underscore the attractiveness of stem cell applications in wound care. This systematic review explores the clinical utilization of stem cells and stem cell products, providing valuable insights into their role as ancillary methods in treating chronic wounds.

Photobiomodulation preconditioned diabetic adipose derived stem cells with additional photobiomodulation: an additive approach for enhanced wound healing in diabetic rats with a delayed healing wound

In this preclinical investigation, we examined the effects of combining preconditioned diabetic adipose-derived mesenchymal stem cells (AD-MSCs) and photobiomodulation (PBM) on a model of infected ischemic delayed healing wound (injury), (IIDHWM) in rats with type I diabetes (TIDM). During the stages of wound healing, we examined multiple elements such as stereology, macrophage polarization, and the mRNA expression levels of stromal cell-derived factor (SDF)-1α, vascular endothelial growth factor (VEGF), hypoxia-induced factor 1α (HIF-1α), and basic fibroblast growth factor (bFGF) to evaluate proliferation and inflammation. The rats were grouped into: (1) control group; (2) diabetic-stem cells were transversed into the injury site; (3) diabetic-stem cells were transversed into the injury site then the injury site exposed to PBM; (4) diabetic stem cells were preconditioned with PBM and implanted into the wound; (5) diabetic stem cells were preconditioned with PBM and transferred into the injury site, then the injury site exposed additional PBM. While on both days 4, and 8, there were advanced histological consequences in groups 2-5 than in group 1, we found better results in groups 3-5 than in group 2 (p < 0.05). M1 macrophages in groups 2-5 were lower than in group 1, while groups 3-5 were reduced than in group 2 (p < 0.01). M2 macrophages in groups 2-5 were greater than in group 1, and groups 3-5 were greater than in group 2. (p ≤ 0.001). Groups 2-5 revealed greater expression levels of bFGF, VEGF, SDF- 1α, and HIF- 1α genes than in group 1 (p < 0.001). Overall group 5 had the best results for histology (p < 0.05), and macrophage polarization (p < 0.001). AD-MSC, PBM, and AD-MSC + PBM treatments all enhanced the proliferative stage of injury repairing in the IIDHWM in TIDM rats. While AD-MSC + PBM was well than the single use of AD-MSC or PBM, the best results were achieved with PBM preconditioned AD-MSC, plus additional PBM of the injury.

Enhancing diabetic wound healing: advances in electrospun scaffolds from pathogenesis to therapeutic applications

Diabetic wounds are a significant subset of chronic wounds characterized by elevated levels of inflammatory cytokines, matrix metalloproteinases (MMPs), and reactive oxygen species (ROS). They are also associated with impaired angiogenesis, persistent infection, and a high likelihood of hospitalization, leading to a substantial economic burden for patients. In severe cases, amputation or even mortality may occur. Diabetic foot ulcers (DFUs) are a common complication of diabetes, with up to 25% of diabetic patients being at risk of developing foot ulcers over their lifetime, and more than 70% ultimately requiring amputation. Electrospun scaffolds exhibit a structural similarity to the extracellular matrix (ECM), promoting the adhesion, growth, and migration of fibroblasts, thereby facilitating the formation of new skin tissue at the wound site. The composition and size of electrospun scaffolds can be easily adjusted, enabling controlled drug release through fiber structure modifications. The porous nature of these scaffolds facilitates gas exchange and the absorption of wound exudate. Furthermore, the fiber surface can be readily modified to impart specific functionalities, making electrospinning nanofiber scaffolds highly promising for the treatment of diabetic wounds. This article provides a concise overview of the healing process in normal wounds and the pathological mechanisms underlying diabetic wounds, including complications such as diabetic foot ulcers. It also explores the advantages of electrospinning nanofiber scaffolds in diabetic wound treatment. Additionally, it summarizes findings from various studies on the use of different types of nanofiber scaffolds for diabetic wounds and reviews methods of drug loading onto nanofiber scaffolds. These advancements broaden the horizon for effectively treating diabetic wounds.

The risk of pocket infection or bloodstream infection following central venous port placement for the patients with Cetuximab therapy

OBJECTIVE

Cetuximab is a molecular targeted drug that targets epithelial growth factor receptors. The skin toxicity of cetuximab arising from epithelial growth factor inhibition is well known. Some patients with cetuximab therapy decided to make central venous port during the long-term intravenous treatments. Therefore, the author hypothesized that cetuximab administration might increase the risk of central venous port-related infection due to damage to skin barrier function. The main aim of the present study was to investigate the relationship between cetuximab administration and central venous port-related infection.

METHODS

A total of 83 patients had a central venous port placed from 2016 through 2021. We analyzed, retrospectively, the relationship between cetuximab therapy and the incidence of central venous port-related infection involving central line-associated bloodstream infection and pocket infection. Additionally, the risk factors of central venous port-related infection were examined in the population undergoing cetuximab therapy.

RESULTS

In total populations (83 cases), central line-associated bloodstream infection happened in five patients (6%) and pocket infection happened in six patients (7%) after central venous port placement. In the cetuximab therapy group (45 cases), there were four patients with central line-associated bloodstream infection (9%) and six with pocket infection (13%). The pocket infection happened more frequently in the cetuximab group than the other group with significant differences. Additionally, in the cetuximab group, the patients who had an interval of less than seven days between central venous port placement and cetuximab dosing, or central venous port placement preceded by cetuximab dosing had more pocket infection with significant differences.

CONCLUSION

Skin complications after the central venous port placement were related to cetuximab administration and the timing of cetuximab therapy.

Discovery of bioactive peptides as therapeutic agents for skin wound repair

Short sequences of amino acids called peptides have a wide range of biological functions and the potential to treat a number of diseases. Bioactive peptides can be derived from different sources, including marine organisms, and synthetic design, making them versatile candidates for production of therapeutic agents. Their therapeutic effects span across areas such as antimicrobial activity, cells proliferation and migration, synthesis of collagen, and more. This current review explores the fascinating realm of bioactive peptides as promising therapeutic agents for skin wound healing. This review focuses on the multifaceted biological effects of specific peptides, shedding light on their potential to revolutionize the field of dermatology and regenerative medicine. It delves into how these peptides stimulate collagen synthesis, inhibit inflammation, and accelerate tissue regeneration, ultimately contributing to the effective repair of skin wounds. The findings underscore the significant role several types of bioactive peptides can play in enhancing wound healing processes and offer promising insights for improving the quality of life for individuals with skin injuries and dermatological conditions. The versatility of peptides allows for the development of tailored treatments catering to specific wound types and patient needs. As continuing to delve deeper into the realm of bioactive peptides, there is immense potential for further exploration and innovation. Future endeavors may involve the optimization of peptide formulations, elucidation of underlying molecular and cellular mechanisms.

An overview to nanocellulose clinical application: Biocompatibility and opportunities in disease treatment

Recently, the demand for organ transplantation has promptly increased due to the enhanced incidence of body organ failure, the increasing efficiency of transplantation, and the improvement in post-transplant outcomes. However, due to a lack of suitable organs for transplantation to fulfill current demand, significant organ shortage problems have emerged. Developing efficient technologies in combination with tissue engineering (TE) has opened new ways of producing engineered tissue substitutes. The use of natural nanoparticles (NPs) such as nanocellulose (NC) and nano-lignin should be used as suitable candidates in TE due to their desirable properties. Many studies have used these components to form scaffolds and three-dimensional (3D) cultures of cells derived from different tissues for tissue repair. Interestingly, these natural NPs can afford scaffolds a degree of control over their characteristics, such as modifying their mechanical strength and distributing bioactive compounds in a controlled manner. These bionanomaterials are produced from various sources and are highly compatible with human-derived cells as they are derived from natural components. In this review, we discuss some new studies in this field. This review summarizes the scaffolds based on NC, counting nanocrystalline cellulose and nanofibrillated cellulose. Also, the efficient approaches that can extract cellulose with high purity and increased safety are discussed. We concentrate on the most recent research on the use of NC-based scaffolds for the restoration, enhancement, or replacement of injured organs and tissues, such as cartilage, skin, arteries, brain, and bone. Finally, we suggest the experiments and promises of NC-based TE scaffolds.

Scars

Wound healing occurs as a response to disruption of the epidermis and dermis. It is an intricate and well-orchestrated response with the goal to restore skin integrity and function. However, in hundreds of millions of patients, skin wound healing results in abnormal scarring, including keloid lesions or hypertrophic scarring. Although the underlying mechanisms of hypertrophic scars and keloid lesions are not well defined, evidence suggests that the changes in the extracellular matrix are perpetuated by ongoing inflammation in susceptible individuals, resulting in a fibrotic phenotype. The lesions then become established, with ongoing deposition of excess disordered collagen. Not only can abnormal scarring be debilitating and painful, it can also cause functional impairment and profound changes in appearance, thereby substantially affecting patients' lives. Despite the vast demand on patient health and the medical society, very little progress has been made in the care of patients with abnormal scarring. To improve the outcome of pathological scarring, standardized and innovative approaches are required.

Exploring the recent developments of alginate silk fibroin material for hydrogel wound dressing: A review

Hydrogels, a type of polymeric material capable of retaining water within a three-dimensional network, have demonstrated their potential in wound healing, surpassing traditional wound dressings. These hydrogels possess remarkable mechanical, chemical, and biological properties, making them suitable scaffolds for tissue regeneration. This article aims to emphasize the advantages of alginate, silk fibroin, and hydrogel-based wound dressings, specifically highlighting their crucial functions that accelerate the healing process of skin wounds. Noteworthy functions include self-healing ability, water solubility, anti-inflammatory properties, adhesion, antimicrobial properties, drug delivery, conductivity, and responsiveness to stimuli. Moreover, recent advancements in hydrogel technology have resulted in the development of wound dressings with enhanced features for monitoring wound progression, further augmenting their effectiveness. This review emphasizes the utilization of hydrogel membranes for treating excisional and incisional wounds, while exploring recent breakthroughs in hydrogel wound dressings, including nanoparticle composite hydrogels, stem cell hydrogel composites, and curcumin-hydrogel composites. Additionally, the review focuses on diverse synthesis procedures, designs, and potential applications of hydrogels in wound healing dressings.

Composite Hydrogels with Embedded Silver Nanoparticles and Ibuprofen as Wound Dressing

The wound healing process is often slowed down as a result of complications from bacterial infections and inflammatory reactions. Therefore, it is necessary to develop dressings with fast antibacterial and anti-inflammatory activity that shorten the wound healing period by promoting cell migration and proliferation. Chitosan (CS)-based hydrogels have been widely studied for their antibacterial and wound healing capabilities. Herein, we developed a composite hydrogel based on CS and PVA embedding silver nanoparticles (AgNPs) with antibacterial properties and ibuprofen (Ib) as an anti-inflammatory agent. The hydrogel prepared by double physical cross-linking, with oxalic acid and by freeze-thawing, loaded with 0.225 wt.% AgNPs and 0.264 wt.% Ib, displayed good mechanical properties (compressive modulus = 132 kPa), a high swelling degree and sustained drug delivery (in simulated skin conditions). Moreover, the hydrogel showed strong antibacterial activity against S. aureus and K. pneumoniae due to the embedded AgNPs. In vivo, this hydrogel accelerated the wound regeneration process through the enhanced expression of TNF alpha IP8, by activating downstream cascades and supporting the healing process of inflammation; Cox2, which enhances the migration and proliferation of cells involved in re-epithelization and angiogenesis; MHCII, which promotes immune cooperation between local cells, eliminating dead tissue and controlling infection; the intense expression of Col I as a major marker in the tissue granulation process; and αSMA, which marks the presence of myofibroblasts involved in wound closure and indicates ongoing re-epithelization. The results reveal the potential healing effect of CS/PVA/AgNPs/Ib hydrogels and suggest their potential use as wound dressings.

KY19382 Accelerates Cutaneous Wound Healing via Activation of the Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway plays important roles in the multi-phases of wound healing: homeostasis, inflammation, proliferative, and remodeling phases. However, there are no clinically available therapeutic agents targeting the Wnt/β-catenin pathway. In this study, we tested the effect of 5, 6-dichloroindirubin-3'-methoxime (KY19382), a small molecule that activates the Wnt/β-catenin pathway via interference with the function of the negative feedback regulator CXXC5, on cutaneous wound healing. KY19382 significantly enhanced cell migration of human keratinocytes and dermal fibroblasts with increased levels of β-catenin, phalloidin, Keratin 14, proliferating cell nuclear antigen (PCNA), Collagen I, and alpha-smooth muscle actin (α-SMA) by activating the Wnt/β-catenin signaling pathway without causing significant cytotoxicity. In addition, levels of Collagen I, Keratin 14, PCNA, and stem cell markers were significantly increased by KY19382 in a cutaneous murine wound healing model. Moreover, KY19382 treatment accelerated re-epithelialization and neo-epidermis formation with collagen deposition and stem cell activation at an early stage of cutaneous wound healing. Overall, KY19382 accelerates wound healing via activating the Wnt/β-catenin pathway, and may have the potential to be used for the development of a new wound healing agent.

Stem cell-based drug delivery strategy for skin regeneration and wound healing: potential clinical applications

Stem cell-based therapy is widely accepted to be a promising strategy in tissue regenerative medicine. Nevertheless, there are several obstacles to applying stem cells in skin regeneration and wound healing, which includes determining the optimum source, the processing and administration methods of stem cells, and the survival and functions of stem cells in wound sites. Owing to the limitations of applying stem cells directly, this review aims to discuss several stem cell-based drug delivery strategies in skin regeneration and wound healing and their potential clinical applications. We introduced diverse types of stem cells and their roles in wound repair. Moreover, the stem cell-based drug delivery systems including stem cell membrane-coated nanoparticles, stem cell-derived extracellular vesicles, stem cell as drug carriers, scaffold-free stem cell sheets, and stem cell-laden scaffolds were further investigated in the field of skin regeneration and wound healing. More importantly, stem cell membrane-coating nanotechnology confers great advantages compared to other drug delivery systems in a broad field of biomedical contexts. Taken together, the stem cell-based drug delivery strategy holds great promise for treating skin regeneration and wound healing.

16S rRNA gene sequencing reveals the correlation between the gut microbiota and the susceptibility to pathological scars

The gut microbiome profile in patients with pathological scars remains rarely known, especially those patients who are susceptible to pathological scars. Previous studies demonstrated that gut microbial dysbiosis can promote the development of a series of diseases via the interaction between gut microbiota and host. The current study aimed to explore the gut microbiota of patients who are prone to suffer from pathological scars. 35 patients with pathological scars (PS group) and 40 patients with normal scars (NS group) were recruited for collection of fecal samples to sequence the 16S ribosomal RNA (16S rRNA) V3-V4 region of gut microbiota. Alpha diversity of gut microbiota showed a significant difference between NS group and PS group, and beta diversity indicated that the composition of gut microbiota in NS and PS participants was different, which implied that dysbiosis exhibits in patients who are susceptible to pathological scars. Based on phylum, genus, species levels, we demonstrated that the changing in some gut microbiota (Firmicutes; Bacteroides; Escherichia coli, etc.) may contribute to the occurrence or development of pathological scars. Moreover, the interaction network of gut microbiota in NS and PS group clearly revealed the different interaction model of each group. Our study has preliminary confirmed that dysbiosis exhibits in patients who are susceptible to pathological scars, and provide a new insight regarding the role of the gut microbiome in PS development and progression.

Natural Polymer-Based Thin Film Strategies for Skin Regeneration in Lieu of Regenerative Dentistry

Wound healing (WH) is a complex and dynamic process that comprises of a series of molecular and cellular events that occur after tissue injury. The injuries of the maxillofacial and oral region caused by trauma or surgery result in undesirable WH such as delayed wound closure and formation of scar tissue. Skin tissue engineering (TE)/regeneration is an emerging approach toward faster, superior, and more effective resolution of clinically significant wounds effectively. A multitude of TE principles approaches are being put to action for the fabrication of hydrogels, electrospun sheets, 3D scaffolds, and thin films that can be used as wound dressings materials, sutures, or skin substitutes. Thin films are advantageous over other materials owing to their flexibility, ability to provide a barrier against external contamination, easy gaseous exchange, and easy monitoring of wounds. This review focuses on wound-dressing films and their significance and discusses various fabrication techniques. In addition, we explore various natural biopolymers that can be used for fabrication of skin TE materials. Impact Statement In this review article, critical evaluations of natural polymers used in skin regeneration were discussed. Further, the fabrication technology of the 2D and 3D material in wound healing were discussed.

Wound Restorative Power of Halimeda macroloba/ Mesenchymal Stem Cells in Immunocompromised Rats via Downregulating Inflammatory/Immune Cross Talk

Impaired skin wound healing is still a major challenge, especially with immunocompromised patients who express delayed healing and are susceptible to infections. Injection of rat-derived bone marrow mesenchymal stem cells (BMMSCs) via the tail vein accelerates cutaneous wound healing via their paracrine activity. The present work aimed to investigate the combined wound-healing potential of BMMSCs and Halimeda macroloba algae extract in immunocompromised rats. High-resolution liquid chromatography-mass spectrometry (HR-LC-MS) investigation of the extract revealed the presence of variant phytochemicals, mostly phenolics, and terpenoids, known for their angiogenic, collagen-stimulating, anti-inflammatory, and antioxidant properties. The BMMSCs were isolated and characterized for CD markers, where they showed a positive expression of CD90 by 98.21% and CD105 by 97.1%. Twelve days after inducing immunocompromise (40 mg/kg hydrocortisone daily), a circular excision was created in the dorsal skin of rats and the treatments were continued for 16 days. The studied groups were sampled on days 4, 8, 12, and 16 after wounding. The gross/histopathological results revealed that the wound closure (99%), thickness, density of new epidermis and dermis, and skin elasticity in the healed wounds were considerably higher in the BMMSCs/Halimeda group than the control group (p < 0.05). RT-PCR gene expression analysis revealed that the BMMSCs/Halimeda extract combination had perfectly attenuated oxidative stress, proinflammatory cytokines, and NF-_KB activation at day 16 of wounding. The combination holds promise for regenerative medicine, representing a revolutionary step in the wound healing of immunocompromised patients, with still a need for safety assessments and further clinical trials.

miRNome and Proteome Profiling of Human Keratinocytes and Adipose Derived Stem Cells Proposed miRNA-Mediated Regulations of Epidermal Growth Factor and Interleukin 1-Alpha

Wound healing is regulated by complex crosstalk between keratinocytes and other cell types, including stem cells. In this study, a 7-day direct co-culture model of human keratinocytes and adipose-derived stem cells (ADSCs) was proposed to study the interaction between the two cell types, in order to identify regulators of ADSCs differentiation toward the epidermal lineage. As major mediators of cell communication, miRNome and proteome profiles in cell lysates of cultured human keratinocytes and ADSCs were explored through experimental and computational analyses. GeneChip^® miRNA microarray, identified 378 differentially expressed miRNAs; of these, 114 miRNAs were upregulated and 264 miRNAs were downregulated in keratinocytes. According to miRNA target prediction databases and the Expression Atlas database, 109 skin-related genes were obtained. Pathway enrichment analysis revealed 14 pathways including vesicle-mediated transport, signaling by interleukin, and others. Proteome profiling showed a significant upregulation of the epidermal growth factor (EGF) and Interleukin 1-alpha (IL-1α) compared to ADSCs. Integrated analysis through cross-matching the differentially expressed miRNA and proteins suggested two potential pathways for regulations of epidermal differentiation; the first is EGF-based through the downregulation of miR-485-5p and miR-6765-5p and/or the upregulation of miR-4459. The second is mediated by IL-1α overexpression through four isomers of miR-30-5p and miR-181a-5p.

Fat Graft Retention: Adipose Tissue, Adipose-Derived Stem Cells, and Aging

SUMMARY

Over the past 30 years, there has been a dramatic increase in the use of autologous fat grafting for soft-tissue augmentation and to improve facial skin quality. Several studies have highlighted the impact of aging on adipose tissue, leading to a decrease of adipose tissue volume and preadipocyte proliferation and increase of fibrosis. Recently, there has been a rising interest in adipose tissue components, including adipose-derived stem/stromal cells (ASCs) because of their regenerative potential, including inflammation, fibrosis, and vascularization modulation. Because of their differentiation potential and paracrine function, ASCs have been largely used for fat grafting procedures, as they are described to be a key component in fat graft survival. However, many parameters as surgical procedures or adipose tissue biology could change clinical outcomes. Variation on fat grafting methods have led to numerous inconsistent clinical outcomes. Donor-to-donor variation could also be imputed to ASCs, tissue inflammatory state, or tissue origin. In this review, the authors aim to analyze (1) the parameters involved in graft survival, and (2) the effect of aging on adipose tissue components, especially ASCs, that could lead to a decrease of skin regeneration and fat graft retention.

CLINICAL RELEVANCE STATEMENT

This review aims to enlighten surgeons about known parameters that could play a role in fat graft survival. ASCs and their potential mechanism of action in regenerative medicine are more specifically described.

Exploring Iberian Peninsula Lamiaceae as Potential Therapeutic Approaches in Wound Healing

Skin tissue has a crucial role in protecting the human body from external harmful agents, preventing wounds that frequently demand proper healing approaches. The ethnobotanical knowledge of specific regions with further investigation on their medicinal plants has been paramount to create new and effective therapeutical agents, including for dermatological purposes. This review attempts, for the first time, to investigate the traditional applications of Lamiaceae medicinal plants that are already used by local communities in the Iberian Peninsula in wound healing. Henceforward, Iberian ethnobotanical surveys were reviewed, and the information about the traditional wound healing practices of Lamiaceae was comprehensively summarized. Afterwards, the scientific validation of each Lamiaceae species was exhaustively checked. From this, eight out of twenty-nine Lamiaceae medicinal plants were highlighted by their wound-related pharmacological evidence and are in-depth presented in this review. We suggest that future studies should focus on the isolation and identification of the active molecules of these Lamiaceae, followed by robust clinical trials that may confirm the security and effectiveness of such natural-based approaches. This will in turn pave the way for more reliable wound healing treatments.

Injury-induced interleukin-1 alpha promotes Lgr5 hair follicle stem cells de novo regeneration and proliferation via regulating regenerative microenvironment in mice

BACKGROUND

The hair follicles (HFs) are barely regenerated after loss in injuries in mammals as well as in human beings. Recent studies have shown that the regenerative ability of HFs is age-related; however, the relationship between this phenomenon and the stem cell niche remains unclear. This study aimed to find a key secretory protein that promotes the HFs regeneration in the regenerative microenvironment.

METHODS

To explore why age affects HFs de novo regeneration, we established an age-dependent HFs regeneration model in leucine-rich repeat G protein-coupled receptor 5 (Lgr5) + /mTmG mice. Proteins in tissue fluids were analyzed by high-throughput sequencing. The role and mechanism of candidate proteins in HFs de novo regeneration and hair follicle stem cells (HFSCs) activation were investigated through in vivo experiments. The effects of candidate proteins on skin cell populations were investigated by cellular experiments.

RESULTS

Mice under 3-week-old (3W) could regenerate HFs and Lgr5 HFSCs, which were highly correlated with the immune cells, cytokines, IL-17 signaling pathway, and IL-1α level in the regeneration microenvironment. Additionally, IL-1α injection induced de novo regeneration of HFs and Lgr5 HFSCs in 3W mouse model with a 5 mm wound, as well as promoted activation and proliferation of Lgr5 HFSCs in 7-week-old (7W) mice without wound. Dexamethasone and TEMPOL inhibited the effects of IL-1α. Moreover, IL-1α increased skin thickness and promoted the proliferation of human epidermal keratinocyte line (HaCaT) and skin-derived precursors (SKPs) in vivo and in vitro, respectively.

CONCLUSIONS

In conclusion, injury-induced IL-1α promotes HFs regeneration by modulating inflammatory cells and oxidative stress-induced Lgr5 HFSCs regeneration as well as promoting skin cell populations proliferation. This study uncovers the underlying molecular mechanisms enabling HFs de novo regeneration in an age-dependent model.

Bi-layered living cellular construct resulted in greater healing in an alloxan-induced diabetic porcine model

Tissue-engineered skin constructs, including bi-layered living cellular constructs (BLCC) used in the treatment of chronic wounds, are structurally/functionally complex. While some work has been performed to understand their mechanisms, the totality of how BLCC may function in wound healing remains unknown. To this end, we have developed a delayed wound healing model to test BLCC cellular and molecular mechanisms of action. Diabetes was chemically-induced using alloxan in Yucatan miniature pigs, and full-thickness wounds were generated on their dorsum. These wounds were either allowed to heal by secondary intention alone (control) or treated with a single or multiple treatments of a porcine autologous BLCC. Results indicated a single treatment with porcine BLCC resulted in statistically significant wound healing at day 17, while four treatments resulted in statistically significant healing on days 10, 13, and 17 compared to control. Statistically accelerated wound closure was driven by re-epithelialisation rather than contraction or granulation. This porcine diabetic model and the use of a porcine BLCC allowed evaluation of healing responses in vivo without the complications typically seen with either xenogenic responses of human/animal systems or the use of immune compromised animals, expanding the knowledge base around how BLCC may impact chronic wounds.

Polysaccharide-based hydrogel with photothermal effect for accelerating wound healing

Polysaccharide-based hydrogel has excellent biochemical function, abundant sources, good biocompatibility and other advantages, and has a broad application prospect in biomedical fields, especially in the field of wound healing. With its inherent high specificity and low invasive burden, photothermal therapy has shown great application prospect in preventing wound infection and promoting wound healing. Combining polysaccharide-based hydrogel with photothermal therapy (PTT), multifunctional hydrogel with photothermal, bactericidal, anti-inflammatory and tissue regeneration functions can be designed, so as to achieve better therapeutic effect. This review first focuses on the basic principles of hydrogel and PTT, and the types of polysaccharides that can be used to design hydrogels. In addition, according to the different materials that produce photothermal effects, the design considerations of several representative polysaccharide-based hydrogels are emphatically introduced. Finally, the challenges faced by polysaccharide-based hydrogels with photothermal properties are discussed, and the future prospects of this field are put forward.

The antimicrobial, antibiofilm, and wound healing properties of ethyl acetate crude extract of an endophytic fungus Paecilomyces sp. (AUMC 15510) in earthworm model

The endophytic fungus Paecilomyces sp. (AUMC 15510) was isolated from healthy stem samples of the Egyptian medicinal plant Cornulaca monacantha. We used GC-MS and HPLC analysis to identify the bioactive constituents of ethyl acetate crude extract of Paecilomyces sp. (PsEAE). Six human microbial pathogens have been selected to evaluate the antimicrobial activity of PsEAE. Our data showed that the extract has significant antimicrobial activity against all tested pathogens. However, the best inhibitory effect was observed against Bacillus subtilis ATCC 6633 and Pseudomonas aeruginosa ATCC 90274 with a minimum inhibitory concentration (MIC) of 3.9 μg/ml and minimum bactericidal concentration (MBC) of 15.6 μg/ml, for both pathogens. Also, PsEAE exerts a significant inhibition on the biofilm formation of the previously mentioned pathogenic strains. In addition, we evaluated the wound healing efficiency of PsEAE on earthworms (Lumbricus castaneus) as a feasible and plausible model that mimics human skin. Interestingly, PsEAE exhibited a promising wound healing activity and enhanced wound closure. In conclusion, Paecilomyces sp. (AUMC 15510) could be a sustainable source of antimicrobial agents and a potential therapeutic target for wound management.

Euodia daniellii Hemsl. Extract and Its Active Component Hesperidin Accelerate Cutaneous Wound Healing via Activation of Wnt/β-Catenin Signaling Pathway

The activation of the Wnt/β-catenin signaling pathway plays a key role in the wound-healing process through tissue regeneration. The extract of Euodia daniellii Hemsl. (E. daniellii), a member of the Rutaceae family, activates the Wnt/β-catenin signaling pathway. However, the function of E. daniellii in wound healing has not yet been elucidated. We performed a migration assay to determine the wound-healing effect of E. daniellii extract in vitro using human keratinocytes and dermal fibroblast. In addition, a mouse acute wound model was used to investigate the cutaneous wound-healing effect of E. daniellii extract in vivo and confirm the potential mechanism. E. daniellii extract enhanced the migration of human keratinocytes and dermal fibroblasts via the activation of the Wnt/β-catenin pathway. Moreover, the E. daniellii extract increased the levels of keratin 14, PCNA, collagen I, and α-SMA, with nuclei accumulation of β-catenin in vitro. E. daniellii extract also efficiently accelerated re-epithelialization and stimulated wound healing in vivo. Furthermore, we confirmed that hesperidin, one of the components of E. daniellii, efficiently accelerated the migration of human keratinocytes and dermal fibroblasts, as well as wound healing in vivo via the activation of the Wnt/β-catenin pathway. Overall, E. daniellii extract and its active component, hesperidin, have potential to be used as therapeutic agents for wound healing.

Downregulation of Lhx2 Markedly Impairs Wound Healing in Mouse Fetus

Multiple transitions occur in the healing ability of the skin during embryonic development in mice. Embryos up to embryonic day 13 (E13) regenerate completely without a scar after full-thickness wounding. Then, up to E16, dermal structures can be formed, including skin appendages such as hair follicles. However, after E17, wound healing becomes incomplete, and scar formation is triggered. Lhx2 regulates the switch between maintenance and activation of hair follicle stem cells, which are involved in wound healing. Therefore, we investigated the role of Lhx2 in fetal wound healing. Embryos of ICR mice were surgically wounded at E13, E15, and E17, and the expression of Lhx2 along with mitotic (Ki67 and p63) and epidermal differentiation (keratin-10 and loricrin) markers was analyzed. The effect of Lhx2 knockdown on wound healing was observed. Lhx2 expression was not noticed in E13 due to the absence of folliculogenesis but was evident in the epidermal basal layer of E15 and E17 and at the base of E17 wounds, along with Ki67 and p63 expression. Furthermore, Lhx2 knockdown in E15 markedly prolonged wound healing and promoted clear scar formation. Therefore, Lhx2 expression is involved in cell division associated with wound healing and may contribute to scar formation in late embryos.

Electrospun Nanofibers for Wound Management

Electrospun nanofibers show great potential in biomedical applications. This mini review article traces the recent advances in electrospun nanofibers for wound management via various approaches. Initially, we provide a short note on the four phases of wound healing, including hemostasis, inflammation, proliferation, and remodeling. Then, we state how the nanofiber dressings can stop bleeding and reduce the pain. Following that, we discuss the delivery of therapeutics and cells using different types of nanofibers for enhancing cell migration, angiogenesis, and re-epithelialization, resulting in the promotion of wound healing. Finally, we present the conclusions and future perspectives regarding the use of electrospun nanofibers for wound management.

Galectin 1-A Key Player between Tissue Repair and Fibrosis

Galectins are ten family members of carbohydrate-binding proteins with a high affinity for β galactose-containing oligosaccharides. Galectin-1 (Gal-1) is the first protein discovered in the family, expressed in many sites under normal and pathological conditions. In the first part of the review article, we described recent advances in the Gal-1 modulatory role on wound healing, by focusing on the different phases triggered by Gal-1, such as inflammation, proliferation, tissue repair and re-epithelialization. On the contrary, Gal-1 persistent over-expression enhances angiogenesis and extracellular matrix (ECM) production via PI3K/Akt pathway activation and leads to keloid tissue. Therefore, the targeted Gal-1 modulation should be considered a method of choice to treat wound healing and avoid keloid formation. In the second part of the review article, we discuss studies clarifying the role of Gal-1 in the pathogenesis of proliferative diabetic retinopathy, liver, renal, pancreatic and pulmonary fibrosis. This evidence suggests that Gal-1 may become a biomarker for the diagnosis and prognosis of tissue fibrosis and a promising molecular target for the development of new and original therapeutic tools to treat fibrosis in different chronic diseases.

Silver Nanofunctionalized Stent after Radiofrequency Ablation Suppresses Tissue Hyperplasia and Bacterial Growth

Intraductal radiofrequency (RF) ablation combined with placement of a self-expandable metal stent (SEMS) for malignant biliary obstruction has risks such as stent- and heat-induced biliary sludge and restenosis. Here, we investigated the efficacy of a silver nanoparticles (AgNPs)-coated SEMS to inhibit tissue hyperplasia and bacterial growth caused by RF ablation with stent placement in the rabbit bile duct. The release behavior and antibacterial effects of AgNPs-coated SEMSs were evaluated. Then, SEMSs were successfully placed in all rabbits immediately after RF ablation. Ag ions were rapidly released at the beginning and then showed a gradual release behavior. The AgNPs-coated SEMS significantly inhibited bacterial activity compared to the uncoated SEMS (p < 0.05). Cholangiography and histological examination confirmed that the level of tissue hyperplasia was significantly lower in the AgNPs group than in the control group (all p < 0.05). Immunohistochemistry analyses revealed that TUNEL-, HSP 70-, and α-SMA-positive areas were significantly lower in the AgNPs group than in the control group (all p < 0.05). Intraductal RF ablation combined with nanofunctionalized stent placement represents a promising new approach for suppressing thermal damage as well as stent-induced tissue hyperplasia and bacterial growth.

Approaches for Regenerative Healing of Cutaneous Wound with an Emphasis on Strategies Activating the Wnt/β-Catenin Pathway

Significance: In adult mammals, spontaneous repair of a cutaneous wound occurs slowly and leaves a scar with skin adnexa deficiencies. To accelerate cutaneous wound-healing rates and avoid scar formation, current studies have focused on regenerative therapies. Recent Advances: Emerging therapeutics for regenerative wound healing often focus on the use of growth factors and stem cells. However, these therapeutic approaches have limited routine clinical use due to high costs and technical requirements. Critical Issue: Understanding the molecular mechanisms involved in the signaling pathways for cutaneous wound healing and neogenic synthesis of the skin components is important for identification of novel targets for the development of regenerative wound-healing agents. Future Directions: The Wnt/β-catenin pathway is a well-known key player for enhancement of the overall healing process involving tissue regeneration via crosstalk with other signaling pathways. Strategies that activate the Wnt/β-catenin pathway via modulation of the pathway-controlling regulatory factors could provide effective therapeutic approaches for regenerative wound healing.

Porous polysaccharide scaffolds: Proof of concept study on wound healing and stem cell differentiation

The combination of desirable polymer properties and methods for synthesis, utilizing materials with various architectures, could be adopted for diverse clinical applications such as wound healing as well as stem cell differentiation. Natural polymers, particularly polysaccharides, are biocompatible and are reported to have structural similarities with extracellular matrix components. In this scenario, the present study fabricated a porous scaffold using a polysaccharide, galactoxyloglucan, isolated from Tamarind seed kernel, and studied its applications in stem cell attachment and wound healing. In-growth of human mesenchymal stem cells (hMSCs) presented a rounded morphology with increased proliferation. Scaffolds were surface-functionalized with silver nanoparticles to increase the antibacterial activity and the wound healing potential evaluated in preclinical mouse models. The current study provides an insight into how stem cells attach and grow in a naturally derived low-cost polysaccharide scaffold with antibacterial, biocompatible, and biodegradable properties.

The Immunological Impact of IL-1 Family Cytokines on the Epidermal Barrier

The skin barrier would not function without IL-1 family members, but their physiological role in the immunological aspects of skin barrier function are often overlooked. This review summarises the role of IL-1 family cytokines (IL-1α, IL-1β, IL-1Ra, IL-18, IL-33, IL-36α, IL-36β, IL-36γ, IL-36Ra, IL-37 and IL-38) in the skin. We focus on novel aspects of their interaction with commensals and pathogens, the important impact of proteases on cytokine activity, on healing responses and inflammation limiting mechanisms. We discuss IL-1 family cytokines in the context of IL-4/IL-13 and IL-23/IL-17 axis-driven diseases and highlight consequences of human loss/gain of function mutations in activating or inhibitory pathway molecules. This review highlights recent findings that emphasize the importance of IL-1 family cytokines in both physiological and pathological cutaneous inflammation and emergent translational therapeutics that are helping further elucidate these cytokines.

Electrospun polysaccharide scaffolds: wound healing and stem cell differentiation

Irrespective of the labyrinth of fastidiously woven artificial scaffolds, the lack of biocompatibility hampers effective clinical translation, which is the definitive purpose of any biomedical system or device. Hence, the current exploration deals with the fabrication of scaffolds with enhanced bioactivities for wound healing. The methodology used for the fabrication of the scaffolds was electrospinning of the polysaccharide, which is isolated from tamarind seed kernel using the electrospinning process. To improve the antimicrobial activity of the scaffolds, in-house synthesized silver nanoparticles were added to the scaffolds. Wound healing and antimicrobial efficiency of the scaffolds were established in murine models. An insight into the wound healing mechanism was also analyzed using differentiation screening of stem cells grown on scaffolds. The results showed that newly synthesized scaffolds presented excellent wound healing ability along with antimicrobial activity. Furthermore, detailed toxicological evaluations through the histopathology and collagen staining wound sections, the probability of any off-target effects were also ruled out. Differentiation screening showed that adipogenesis was more prominent in cells attached to the scaffolds and markers of adipogenesis were strongly expressed in fluorescent microscopy. Thus we hope that the scaffolds mediate stem cell differentiation in wounds and promote a progressive healing response. Results thus obtained were encouraging and further studies need to embark on to establish the combined role in all aspects studied here.

Application of Electrospun Nanofiber Membrane in the Treatment of Diabetic Wounds

Diabetic wounds are complications of diabetes which are caused by skin dystrophy because of local ischemia and hypoxia. Diabetes causes wounds in a pathological state of inflammation, resulting in delayed wound healing. The structure of electrospun nanofibers is similar to that of the extracellular matrix (ECM), which is conducive to the attachment, growth, and migration of fibroblasts, thus favoring the formation of new skin tissue at the wound. The composition and size of electrospun nanofiber membranes can be easily adjusted, and the controlled release of loaded drugs can be realized by regulating the fiber structure. The porous structure of the fiber membrane is beneficial to gas exchange and exudate absorption at the wound, and the fiber surface can be easily modified to give it function. Electrospun fibers can be used as wound dressing and have great application potential in the treatment of diabetic wounds. In this study, the applications of polymer electrospun fibers, nanoparticle-loaded electrospun fibers, drug-loaded electrospun fibers, and cell-loaded electrospun fibers, in the treatment of diabetic wounds were reviewed, and provide new ideas for the effective treatment of diabetic wounds.

Combined CO2 and dye laser technique in the treatment of outcomes due to flap necrosis after surgery for basal cell carcinoma on the nose

BACKGROUND AND OBJECTIVE

Basal cell carcinoma (BCC) is the most frequent cutaneous cancer worldwide, and the nasal area is the most commonly affected region. Skin flaps are usually performed to achieve radical results, but various adverse events often occur. The necrosis of the skin flap is one of the most frequently observed, resulting in scars and anti-aesthetic outcomes. Ablative and non-ablative lasers have been proposed to improve scars resulting from surgical failure and skin flap necrosis.

STUDY DESIGN/MATERIALS AND METHODS

This study aims to evaluate a new laser protocol combining ablative CO₂ -laser with flashlamp pulsed dye laser for the treatment of nasal scars resulting from the necrosis of flap that occurred after surgery. Twelve patients were enrolled in the study, and a total of five laser sessions were planned, spaced from 14 days to 1 month apart.

RESULTS

Seven out of 12 patients underwent all the five laser sessions planned, while 5/12 patients achieved optimal cosmetic results within the fourth session. Eighty percent of the patients reported good/optimal cosmetic results, and no significant side effects were observed during the study.

CONCLUSION

Combining fractionated CO₂ laser with flashlamp pulsed dye laser represents a new effective modality for treating skin flap necrosis after BBC removal, representing a valid alternative to other surgical procedures.

Wound Healing and Therapy in Soft Tissue Defects of the Hand and Foot from a Surgical Point of View

Wounds and tissue defects of the hand and foot often lead to severe functional impairment of the affected extremity. Next to general principles of wound healing, special functional and anatomic considerations must be taken into account in the treatment of wounds in these anatomical regions to achieve a satisfactory reconstructive result. In this article, we outline the concept of wound healing and focus on the special aspects to be considered in wounds of the hand and foot. An overview of different treatment and dressing techniques is given with special emphasis on the reconstruction of damaged structures by plastic surgical means.

Insight into Factors Influencing Wound Healing Using Phosphorylated Cellulose-Filled-Chitosan Nanocomposite Films

Marine polysaccharides are believed to be promising wound-dressing nanomaterials because of their biocompatibility, antibacterial and hemostatic activity, and ability to easily shape into transparent films, hydrogels, and porous foams that can provide a moist micro-environment and adsorb exudates. Current efforts are firmly focused on the preparation of novel polysaccharide-derived nanomaterials functionalized with chemical objects to meet the mechanical and biological requirements of ideal wound healing systems. In this contribution, we investigated the characteristics of six different cellulose-filled chitosan transparent films as potential factors that could help to accelerate wound healing. Both microcrystalline and nano-sized cellulose, as well as native and phosphorylated cellulose, were used as fillers to simultaneously elucidate the roles of size and functionalization. The assessment of their influences on hemostatic properties indicated that the tested nanocomposites shorten clotting times by affecting both the extrinsic and intrinsic pathways of the blood coagulation system. We also showed that all biocomposites have antioxidant capacity. Moreover, the cytotoxicity and genotoxicity of the materials against two cell lines, human BJ fibroblasts and human KERTr keratinocytes, was investigated. The nature of the cellulose used as a filler was found to influence their cytotoxicity at a relatively low level. Potential mechanisms of cytotoxicity were also investigated; only one (phosphorylated microcellulose-filled chitosan films) of the compounds tested produced reactive oxygen species (ROS) to a small extent, and some films reduced the level of ROS, probably due to their antioxidant properties. The transmembrane mitochondrial potential was very slightly lowered. These biocompatible films showed no genotoxicity, and very importantly for wound healing, most of them significantly accelerated migration of both fibroblasts and keratinocytes.

Production and Characterization of Chitooligosaccharides: Evaluation of Acute Toxicity, Healing, and Anti-Inflammatory Actions

The search for promising biomolecules such as chitooligosaccharides (COS) has increased due to the need for healing products that act efficiently, avoiding complications resulting from exacerbated inflammation. Therefore, this study aimed to produce COS in two stages of hydrolysis using chitosanases derived from Bacillus toyonensis. Additionally, this study aimed to structurally characterize the COS via mass spectrometry, to analyze their biocompatibility in acute toxicity models in vivo, to evaluate their healing action in a cell migration model in vitro, to analyze the anti-inflammatory activity in in vivo models of xylol-induced ear edema and zymosan-induced air pouch, and to assess the wound repair action in vivo. The structural characterization process pointed out the presence of hexamers. The in vitro and in vivo biocompatibility of COS was reaffirmed. The COS stimulated the fibroblast migration. In the in vivo inflammatory assays, COS showed an antiedematogenic response and significant reductions in leukocyte migration, cytokine release, and protein exudate. The COS healing effect in vivo was confirmed by the significant wound reduction after seven days of the experiment. These results indicated that the presence of hexamers influences the COS biological properties, which have potential uses in the pharmaceutical field due to their healing and anti-inflammatory action.

The role of Helianthus tuberosus powder in healing of full-thickness wounds in mice

Background and Aim

Recently, many medicinal plants have received considerable attention in the medical field because of their role in the wound healing potential. This study aimed to determine the effectiveness of H. tuberosus powder on the healing pathway of full-thickness cutaneous wounds in a mouse model.

Materials and Methods

H. tuberosus powder was prepared by a freeze-drying process using a lyophilizer and its active ingredients were evaluated by high-performance liquid chromatography (HPLC), while its antibacterial properties were evaluated by agar well diffusion assay. The percentage wound contraction was also assessed. Thirty mice were used, which were divided equally into two groups, a control group and a treated group. A full-thickness wound, 1 cm×1 cm in size, was established on the dorsal aspect of the thoracolumbar region, into which H. tuberosus powder was topically applied in the treated group. In contrast, the control group was left without any treatment. The animals were euthanized on days 7, 14, and 21 after wounding for histopathological study.

Results

The agar well diffusion method indicated the antibacterial activity of H. tuberosus, while the HPLC results indicated that the active ingredients of H. tuberosus powder mainly consisted of three major kinds of fatty acid. In addition, the macroscopic results of wound contraction rate and the histopathological outcomes of the healing process were significantly (p≤0.05) enhanced in the treated group compared with those in the control group.

Conclusion

H. tuberosus powder acts as an antibacterial agent with the ability to enhance the wound healing process.

Effects of Mesenchymal Stem Cell-Derived Paracrine Signals and Their Delivery Strategies

Mesenchymal stem cells (MSCs) have been widely studied as a versatile cell source for tissue regeneration and remodeling due to their potent bioactivity, which includes modulation of inflammation response, macrophage polarization toward proregenerative lineage, promotion of angiogenesis, and reduction in fibrosis. This review focuses on profiling the effects of paracrine signals of MSCs, commonly referred to as the secretome, and highlighting the various engineering approaches to tune the MSC secretome. Recent advances in biomaterials‐based therapeutic strategies for delivery of MSCs and MSC‐derived secretome in the form of extracellular vesicles are discussed, along with their advantages and challenges.

Could cold plasma act synergistically with allogeneic mesenchymal stem cells to improve wound skin regeneration in a large size animal model?

Skin wound healing may sometimes lead to open sores that persist for long periods and expensive hospitalization is needed. Among different kinds of therapeutic innovative approaches, mesenchymal stem cells (MSCs) and low-temperature atmospheric pressure cold plasma (ionized gas) have been recently tested to improve this regenerative process. To optimize wound healing the present study intended to combine, for the first time, these two novel approaches in a large size animal wound healing model with the aim of assessing the putative dual beneficial effects. Based on clinical, histopathological, and molecular results a synergistic action in a second intention healing wound in sheep has been observed. Experimental wounds treated with cold plasma and MSCs showed a slower but more effective healing compared to the single treatment, as observed in previous studies. The combined treatment improved the correct development of skin appendages and structural proteins of the dermis showing the potential of the dual combination as a safe and effective tool for skin regeneration in the veterinary clinical field.

Effects of electrical stimulation on skin surface

ABSTRACT

Skin is the largest organ in the body, and directly contact with the external environment. Articles on the role of micro-current and skin have emerged in recent years. The function of micro-current is various, including introducing various drugs into the skin locally or throughout the body, stimulating skin wounds healing through various currents, suppressing pain caused by various diseases, and promoting blood circulation for postoperative muscle rehabilitation, etc. This article reviews these efforts. Compared with various physical and chemical medical therapies, micro-current stimulation provides a relatively safe, non-invasive therapy with few side effects, giving modern medicine a more suitable treatment option. At the same time, the cost of the electrical stimulation generating device is relatively low, which makes it have wider space to and more clinical application value. The current micro-current stimulation technology has become more and more mature, but there are still many problems in its research. The design of the experiment and the selection of the current parameters not standardized and rigorous. Now, clear regulations are needed to regulate this field. Micro-current skin therapy has become a robust, reliable, and well-structured system.

Keloid disorder: Fibroblast differentiation and gene expression profile in fibrotic skin diseases

Keloid disorder, a group of fibroproliferative skin diseases, is characterized by unremitting accumulation of the extracellular matrix (ECM) of connective tissue, primarily collagen, to develop cutaneous tumors on the predilection sites of skin. There is a strong genetic predisposition for keloid formation, and individuals of African and Asian ancestry are particularly prone. The principal cell type responsible for ECM accumulation is the myofibroblast derived from quiescent resident skin fibroblasts either through trans-differentiation or from keloid progenitor stem cells with capacity for multi-lineage differentiation and self-renewal. The biosynthetic pathways leading to ECM accumulation are activated by several cytokines, but particularly by TGF-β signalling. The mechanical properties of the cellular microenvironment also play a critical role in the cell's response to TGF-β, as demonstrated by culturing of fibroblasts derived from keloids and control skin on substrata with different degrees of stiffness. These studies also demonstrated that culturing of fibroblasts on tissue culture plastic in vitro does not reflect their biosynthetic capacity in vivo. Collectively, our current understanding of the pathogenesis of keloids suggests a complex network of interacting cellular, molecular and mechanical factors, with distinct pathways leading to myofibroblast differentiation and activation. Keloids can serve as a model system of fibrotic diseases, a group of currently intractable disorders, and deciphering of the critical pathogenetic steps leading to ECM accumulation is expected to identify targets for pharmacologic intervention, not only for keloids but also for a number of other, both genetic and acquired, fibrotic diseases.