Skin tissue engineering: wound healing based on stem-cell-based therapeutic strategies

3D-printed multifunctional bilayer scaffold with sustained release of apoptotic extracellular vesicles and antibacterial coacervates for enhanced wound healing

Full-thickness skin defects pose significant challenges to physical and psychological health while traditional skin grafting techniques are associated with limitations. Herein, we present a 3D-printed multifunctional bilayer scaffold that incorporates apoptotic extracellular vesicles (ApoEVs) and antibacterial coacervates to prevent wound infection and promote wound healing. The ApoEVs were continuously released from the lower layer of the scaffold with large pores to promote angiogenesis and collagen deposition. Meanwhile, the pH-responsive curcumin-containing coacervates were released from the upper layer of the scaffold with dense pores to exert antibacterial and reactive oxygen species scavenging ability. In vivo experiments showed that the scaffold accelerated wound healing and improved healing quality by promoting a more organized collagen arrangement and reducing hyperplastic scar tissue. Furthermore, it effectively reduced hyperplastic scar tissue, resulting in a decrease in the average scar area from 73.3 % to 19.9 %. RNA sequencing analysis revealed that the scaffold upregulated genes associated with cell proliferation and downregulated genes related to inflammation, indicating its potential therapeutic applications for wound healing. This multifunctional bilayer scaffold represents a promising candidate for the treatment of full-thickness skin defects, offering rationales for designing skin scaffolds for regenerative medicine applications.

Biomimetic gradient hydrogel with fibroblast spheroids for full-thickness skin regeneration

Hydrogel-based scaffolds have been widely investigated for their use in tissue engineering to accelerate tissue regeneration. However, replicating the physiological microenvironments of tissues with appropriate biological cues remains challenging. Recent advances in gradient hydrogels have transformed tissue-engineering research by providing precise structures that mimic the extracellular matrix of natural tissues. Unlike conventional homogeneously structured hydrogels, gradient hydrogels provide a better bio-mimicking microenvironment for combined cell therapies in chronic wound treatment by regulating various cell behaviors, such as proliferation, migration, and differentiation. Here, we present the integration of L929 mouse fibroblast spheroids into gradient hydrogels to mimic the dermal stiffness microenvironment and we investigated their impact on full-thickness skin regeneration. A stiffness gradient was achieved by modulating the concentration of methacrylated hyaluronic acid (HA-MA) with varying degrees of methacrylation, using a dual-syringe pump system. The encapsulation of L929 spheroids with gradient hydrogel facilitated skin cell organization in a hierarchically ordered configuration, leading to full-thickness wound healing that was 1.53 times faster than the untreated group in a rat model. This study provides a method for investigating the potential role of gradient hydrogels in various tissue engineering and regeneration applications.

Construction of multifunctional tracheal substitute based on silk fibroin methacryloyl and hyaluronic acid methacryloyl with decellularized cartilaginous matrix for tracheal defect repair

The regeneration and functional recovery of tracheal tissue are of paramount importance in the research of tissue-engineered trachea. Current constructs still face some limitations in simulating the complex natural microenvironment and achieving better regenerative capacity and functional recovery. To address these challenges, the application of hydrogels with three-dimensional (3D) network structure and extracellular matrix derived from decellularized tissues and cells has become a more promising strategy. This study aims to introduce a novel bilayer multifunctional tissue-engineered tracheal substitute. Firstly, the mesh polycaprolactone (PCL) scaffold was printed by 3D printing technology, and the concentration of Silk Fibroin Methacryloyl (SilMA) hydrogel suitable for cell adhesion and proliferation and the concentration of Hyaluronic Acid Methacryloyl (HAMA) hydrogel suitable for 3D culture of chondrocytes were selected. Subsequently, the decellularized cartilaginous matrix (DCM) solution was obtained and the concentration that promotes chondrocyte proliferation and migration was screened. Finally, the multifunctional tracheal substitute, which features a HAMA-DCM composite hydrogel loaded with autologous chondrocytes as the basic framework to simulate the outer cartilaginous layer, and a 3D-printed PCL mesh scaffold coated with SilMA hydrogel loaded with autologous epithelial cells serves as internal support to simulate the inner airway epithelial layer, was prepared. Whether it was for repairing window-shape defect for 8 w or conducting long-segment in situ transplantation for 12 w, it achieved satisfactory surgical outcomes, including epithelial crawling, cartilage regeneration, and vascular remodeling.

Three-dimensional bio-derived materials for biomedical applications: challenges and opportunities

Three-dimensional (3D) bio-derived materials are emerging as a promising approach to enhance wound healing therapies. These innovative materials can be tailored to meet the specific needs of various wound types and patients, facilitating the controlled release of therapeutic agents such as growth factors and antibiotics, which promote cell growth and tissue regeneration. Despite their potential, significant challenges remain in achieving optimal biocompatibility, ensuring structural integrity, and maintaining precise release mechanisms. Additionally, issues such as scalability, cost-effectiveness, and regulatory compliance pose substantial barriers to widespread use. However, recent advances in materials science and interdisciplinary research offer new opportunities to overcome these challenges. This review provides a comprehensive analysis of the current state of 3D bio-derived materials in biomedical applications, highlighting the types of materials available, their advantages and limitations, and the progress made in their design and development. It also outlines new directions for future research aimed at bridging the gap between scientific discoveries and their practical applications in injury healing strategies. The findings of this review underscore the significant potential of 3D bio-derived materials in revolutionizing wound healing and advancing personalized therapeutic approaches.

A Comprehensive Review: Advances in Mesenchymal Stem Cell Applications for Burn Wound Repair

Tissue repair following skin injury is a complex process that encompasses hemostasis, inflammation, tissue cell proliferation, and structural remodeling. Mesenchymal stem cells (MSCs) are derived from the mesodermal layer of tissues and possess multidirectional differentiation potential and self-renewal capabilities. MSCs from various sources, including the bone marrow, adipose tissue, dental pulp, umbilical cord, and amniotic membrane, have demonstrated effectiveness in promoting skin injury repair. They aid in this process by fostering the formation of new blood vessels in damaged tissues, self-renewal, or transdifferentiation into skin or sweat gland cells. Moreover, MSCs promote the proliferation and migration of skin cells, reduce wound inflammation, and restore the extracellular matrix through paracrine secretion. In this paper, we review recent findings regarding MSCs and their role in burn wound repair. Additionally, we explore the potential of combining MSCs with various biomaterials for treating burn wounds and analyze clinical cases wherein MSCs were administered to patients, offering insights into ongoing research on MSC-based therapies for skin injuries.

Functional polysaccharide-based hydrogel in bone regeneration: From fundamentals to advanced applications

Bone regeneration is limited and generally requires external intervention to promote effective repair. Autografts, allografts, and xenografts as traditional methods for addressing bone defects have been widely utilized, their clinical applicability is limited due to their respective disadvantages. Fortunately, functional polysaccharide hydrogels have gained significant attention in bone regeneration due to their exceptional drug-loading capacity, biocompatibility, and ease of chemical modification. They also provide an optimal microenvironment for bone repair and regeneration. This review provides an overview of various functional polysaccharide hydrogels derived from biocompatible materials, focusing on their applications in intelligent delivery systems, bone tissue regeneration, and cartilage defect repair. Particularly, the incorporation of bioactive molecules into the design of functional polysaccharide hydrogels has been shown to significantly enhance bone regeneration. Additionally, this review emphasizes the preparation methods for functional polysaccharide hydrogels and associated the bone healing mechanisms. Finally, the limitations and future prospects of functional polysaccharide hydrogels are thoroughly evaluated.

Nano CaCO3 mediated in vitro and in vivo wound healing characteristics of chitosan films without added drugs

The proposed investigation aims towards introducing a facile and cost-effective chitosan-based material for healing of full thickness wounds via stimulation of keratinocyte at wound junction to yield faster closure. Chitosan (CS) crosslinked polyacrylic acid (PAA) polymeric networks are chosen as the matrix element to incorporate gold nanoparticles (Au Nps) and nano calcium carbonate (CaCO3 Nps) via covalent and electrostatic interactions. The as-synthesized CS/PAA@Au/CaCO3 nanocomposite hydrogels reveal high in vitro and in vivo biocompatibility against human kidney epithelial (HKE) cells and drosophila larvae, with minimum cell viability of 88.45 % at high doses of 87.5 μg/μL. The innate pH responsive swelling behaviour (1450 %) and WVTR (8.451 mg·cm-2·h-1), hemocompatibility, bioadhesivity along with antibacterial and anti-biofilm activity of the nanocomposite hydrogels against S. aureus and E. coli provide prior motivation to escalate the study towards in vivo wound healing in invertebrates (D.melanogaster) and vertebrates (Sprague-Dawley rats). The proposed hydrogels show accelerated healing in invertebrates and vertebrates, i.e., complete recovery in 3 h and 11 days, respectively. The histopathology analysis establishes the deposition of highly aligned collagen fibers on the wound surface supported by the tight keratinocyte junction at wound surface by the action of calcium ions for which the material becomes promising for wound healing applications.

Stimuli-Responsive Self-Healing Ionic Gels: A Promising Approach for Dermal and Tissue Engineering Applications

The rapid increase in the number of stimuli-responsive polymers, also known as smart polymers, has significantly advanced their applications in various fields. These polymers can respond to multiple stimuli, such as temperature, pH, solvent, ionic strength, light, and electrical and magnetic fields, making them highly valuable in both the academic and industrial sectors. Recent studies have focused on developing hydrogels with self-healing properties that can autonomously recover their structural integrity and mechanical properties after damage. These hydrogels, formed through dynamic covalent reactions, exhibit superior biocompatibility, mechanical strength, and responsiveness to stimuli, particularly pH changes. However, conventional hydrogels are limited by their weak and brittle nature. To address this, ionizable moieties within polyelectrolytes can be tuned to create ionically cross-linked hydrogels, leveraging natural polymers such as alginate, chitosan, hyaluronic acid, and cellulose. The integration of ionic liquids into these hydrogels enhances their mechanical properties and conductivity, positioning them as significant self-healing agents. This review focuses on the emerging field of stimuli-responsive ionic-based hydrogels and explores their potential in dermal applications and tissue engineering.

Autonomous, Moisture-Driven Flexible Electrogenerative Dressing for Enhanced Wound Healing

Electrotherapy has shown considerable potential in treating chronic wounds, but conventional approaches relying on bulky external power supplies and mechanical force are limited in their clinical utility. This study introduces an autonomous, moisture-driven flexible electrogenerative dressing (AMFED) that overcomes these limitations. The AMFED integrates a moist-electric generator (MEG), an antibacterial hydrogel dressing, and concentric molybdenum (Mo) electrodes to provide a self-sustaining electrical supply and potent antibacterial activity against Staphylococcus aureus and Escherichia coli. The MEG harnesses chemical energy from moisture to produce a stable direct current of 0.61 V without external input, delivering this therapeutic electrical stimulation to the wound site through the Mo electrodes. The AMFED facilitates macrophage polarization toward reparative M2 phenotype and regulates inflammatory cytokines. Moreover, in vivo studies suggest that the AMFED group significantly enhances chronic wound healing, with an approximate 41% acceleration compared to the control group. Using a diabetic mouse wound model, the AMFED demonstrates its effectiveness in promoting nerve regulation, epithelial migration, and vasculogenesis. These findings present a novel and efficient platform for accelerating chronic wound healing.

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

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

The efficacy of miR-141-3p to facilitate the healing of wounds and prevent scarring in mice by blocking the JNK/ERK pathway via HDAC6 silencing

PURPOSE

Adipose-derived mesenchymal stem cells (ADSCs) exosomes (AD-Exos) are a novel and promising therapeutic approach for skin damage repair. This investigation seeks to assess the potential clinical utility of miR-141-3p found in AD-exos for expediting wound healing.

METHODS

ADSCs were isolated from the wounded patients' tissue and validated via flow cytometry, and the mineralization and adipogenic capabilities of ADSCs were assessed respectively. Additionally, exosomes were isolated and identified. miR-141-3p and HDAC6.protein level were tested. Full-thickness wound models were created on the backs of mice, HE staining, ELISA, and immunohistochemistry were used to assess the influences of AD-exos on wound healing, inflammation, and new blood vessel formation Western blot was to assess the related-protein levels of JNK/ERK pathway. AQ1 Meanwhile, Dual-Luciferase assay confirmed the relationship between miR-141-3p and HDAC6.

RESULTS

The isolated cells highly express surface markers of mesenchymal stem cells and possess the potential for multidirectional differentiation, confirming them to be ADSCs. And miR-141-3p down-regulated but HDAC6 up-regulated in the serum and AD-exos of wounded patients. miR-141-3p could negatively modulate HDAC6. The miR-141-3p in AD-exos accelerated wound healing in mice, mitigated inflammatory responses and scarring in the injured skin tissue, and promoted angiogenesis, moreover, AD-exos could diminish the phosphorylation of JNK and ERK, while HDAC6 overexpressed could weaken these impacts.

CONCLUSION

miR-141-3p in AD-exos can target down regulate HDAC6 expression and inhibit JNK/ERK signaling pathway activation, thereby reducing wound inflammation and promoting angiogenesis and wound healing in mice.

Microporous annealed particle hydrogels in cell culture, tissue regeneration, and emerging application in cancer immunotherapy

Microporous annealed particle (MAP) hydrogels consist of densely crosslinked and annealed hydrogel particles. Compared to common hydrogels, the inherent porosity within and among these hydrogel particles offers interconnected channels for substance exchange in addition to sufficient growth space for cells, thereby forming a three-dimensional culture system that highly mimics the in vivo microenvironment. Such characteristics enable MAP hydrogels to adapt to various requirements of biomedical applications, along with their excellent injectability and mechanical properties. This review initially provides a comprehensive summary of the fabrication methods and material types of MAP hydrogels, alongside an assessment of their mechanical properties and porosity. In vitro studies are evaluated based on the impact of MAP hydrogels on cellular behaviors, focusing on cell proliferation, differentiation, migration, activity, and phenotype. In vivo research highlights the promising applications of MAP hydrogels in tissue regeneration, as well as their innovative use in cancer immunotherapy. Current challenges and future research directions are outlined, underscoring the potential of MAP hydrogels to significantly improve clinical outcomes in cancer treatment and regenerative medicine.

Bioactive Hydrogel Supplemented with Stromal Cell-Derived Extracellular Vesicles Enhance Wound Healing

Background/Objectives: Skin regeneration is a rapidly advancing field with significant implications for regenerative medicine, particularly in treating wounds and burns. This study explores the potential of hydrogels functionalized with fibroblast-derived extracellular vesicles (EVs) to enhance skin regeneration in vivo. Being immunoprivileged, EVs minimize immune rejection, offering an attractive alternative to whole-cell therapies by replicating fibroblasts' key roles in tissue repair. Methods: To promote EVs' versatility and effective application across different conditions, a lyophilization method with lyoprotectants was optimized. Then, EVs were used to functionalize a hydrogel to perform experiments on murine cutaneous wound models. Results: Gelatin methacrylate (GelMA) was selected as the polymeric hydrogel due to its biocompatibility, tunable mechanical properties, and ability to support wound healing. Mechanical tests confirmed GelMA's strength and elasticity for this application. Fibroblast-derived EVs were characterized using Western blot, Transmission Electron Microscopy, and NanoSight analysis, proving their integrity, size distribution, and stability. miRNome profiling identified enriched biological pathways related to cell migration, differentiation, and angiogenesis, emphasizing the critical role of EV cargo in promoting wound repair. In a murine model, hydrogels loaded with fibroblast-derived EVs significantly accelerated wound healing compared to controls (mean wound area 0.62 mm2 and 4.4 mm2, respectively), with faster closure, enhanced epithelialization, increased vascularization, and reduced fibrosis. Notably, the lyoprotectants successfully preserved the EVs' structure and bioactivity during freeze-drying, reducing EVs loss by 35% compared to the control group and underscoring the feasibility of this approach for long-term storage and clinical application. Conclusions: This study introduces a novel scalable and adaptable strategy for regenerative medicine by combining fibroblast-derived EVs with GelMA, optimizing EVs' stability and functionality for enhanced wound healing in clinical settings, even in challenging contexts such as combat zones or large-scale natural disasters.

Design of the Multi-Bioactive Graphene-Oxide/Gelatin/Alginate Scaffolds as Dual ECM-Mimetic and Specific Wound Healing Phase-Target Therapeutic Concept for Advanced Wound Healing

Objectives: To develop and evaluate graphene oxide/gelatin/alginate scaffolds for advanced wound therapy capable of mimicking the native extracellular matrix (ECM) and bio-stimulating all specific phases of the wound healing process, from inflammation and proliferation to the remodeling of damaged skin tissue in three dimensions. Methods: The scaffolds were engineered as interpenetrating polymeric networks by the crosslinking reaction of gelatin in the presence of alginate and characterized by structural, morphological, mechanical, swelling properties, porosity, adhesion to the skin tissue, wettability, and in vitro simultaneous release of the active agents. Biocompatibility of the scaffolds were evaluated in vitro by MTT test on fibroblasts (MRC5 cells) and in vivo using Caenorhabditis elegans assay. Results: The scaffolds exhibited a highly porous interconnected morphology with adjustable porosity (93-96%) and mechanical strength (1.10-2.90 MPa), hydrophilic nature with high capacity to absorb physiological fluids, and stable adhesion to the skin tissue. The obtained results of MRC5 cell viability indicate that the scaffolds are safe for biomedical applications. No mortality was detected among the Caenorhabditis elegans throughout the incubation period, indicating that the scaffolds are not toxic. The results of in vitro release study of allantoin, quercetin, and caffeic acid confirm the scaffolds' significant potential for simultaneous release. Conclusion: The graphene oxide/gelatin/alginate scaffolds are promising candidates for non-invasive, dual ECM-mimetic, and multi-target wound therapy, offering an innovative strategy to address the complexities of wound healing process.

Advancements in bioengineered and autologous skin grafting techniques for skin reconstruction: a comprehensive review

The reconstruction of complex skin defects challenges clinical practice, with autologous skin grafts (ASGs) as the traditional choice due to their high graft take rate and patient compatibility. However, ASGs have limitations such as donor site morbidity, limited tissue availability, and the necessity for multiple surgeries in severe cases. Bioengineered skin grafts (BSGs) aim to address these drawbacks through advanced tissue engineering and biomaterial science. This study conducts a systematic review to describe the benefits and shortcomings of BSGs and ASGs across wound healing efficacy, tissue integration, immunogenicity, and functional outcomes focusing on wound re-epithelialization, graft survival, and overall aesthetic outcomes. Preliminary findings suggest ASGs show superior early results, while BSGs demonstrate comparable long-term outcomes with reduced donor site morbidity. This comparative analysis enhances understanding of bioengineered alternatives in skin reconstruction, potentially redefining best practices based on efficacy, safety, and patient-centric outcomes, highlighting the need for further innovation in bioengineered solutions.

Leveraging Microneedles for Raised Scar Management

Disruption of the molecular pathways during physiological wound healing can lead to raised scar formation, characterized by rigid, thick scar tissue with associated symptoms of pain and pruritus. A key mechanical factor in raised scar development is excessive tension at the wound site. Recently, microneedles (MNs) have emerged as promising tools for scar management as they engage with scar tissue and provide them with mechanical off-loading from both internal and external sources. This review explores the mechanisms by which physical intervention of drug-free MNs alleviates mechanical tension on fibroblasts within scar tissue, thereby promoting tissue remodeling and reducing scar severity. Additionally, the role of MNs as an efficient cargo delivery system for the controlled and sustained release of a wide range of therapeutic agents into scar tissue is highlighted. By penetrating scar tissue, MNs facilitate controlled and sustained localized drug administration to modulate inflammation and fibroblastic cell growth. Finally, the remaining challenges and the future perspective of the field have been highlighted.

3D-Bioprinted Skin Tissues for Improving Wound Healing: Current Status and Perspective

Advancements in tissue engineering enable the fabrication of complex and functional tissues or organs. In particular, bioprinting enables controlled and accurate deposition of cells, biomaterials, and growth factors to create complex 3D skin constructs specific to a particular individual. Despite these advancements, challenges such as vascularization, long-term stability, and regulatory considerations hinder the clinical translation of bioprinted skin constructs. This chapter focuses on such approaches using advanced biomaterials and bioprinting techniques to overcome the current barriers in wound-healing studies. Moreover, it addresses current obstacles in wound-healing studies, highlighting the need for continued research and innovation to overcome these barriers and facilitate the practical utilization of bioprinted skin constructs in clinical settings.

Revealing the Therapeutic Potential of Stem Cells in Burn Healing: A Deeper Understanding of the Therapeutic Mechanisms of Epidermal Stem Cells and Mesenchymal Stem Cells

Background: Burns are a global public health issue and a major cause of disability and death around the world. Stem cells, which are the undifferentiated cells with the potential for indefinite proliferation and multilineage differentiation, have the ability to replace injured skin and facilitate the wound repair process through paracrine mechanisms. In light of this, the present study aims to conduct a bibliometric analysis in order to identify research hotspots of stem cell-related burns and assess global research tendencies. Methods: To achieve this objective, we retrieved scientific publications on burns associated with stem cells covering the period from January 1, 1978, to October 13, 2022, from the Web of Science Core Collection (WoSCC). Bibliometric analyses, including production and collaboration analyses between countries, institutions, authors, and journals, as well as keyword and topic analyses, were conducted using the bibliometrix R package, CiteSpace, and VOSviewer. Results: A total of 1648 burns associated with stem cell documents were published and listed on WOSCC. The most contributive country, institution, journal, and author were the United States, LV Prasad Eye Institute, Burns, and Scheffer C.G. Tseng, respectively. More importantly, combined with historical direct citation network, trend topic analysis, keyword co-occurrence network, and substantial literature analysis, we eventually summarized the research hotspots and frontiers on burns associated stem cell reasearch. Conclusion: The present study obtained deep insight into the developing trends and research hotspots on burns associated with stem cells, which arouses growing concerns and implies increasing clinical implications. The mechanism and therapeutics of epidermal stem cells (ESCs) for burn wounds and the mechanism of mesenchymal stem cells (MSCs) and MSC-derived exosomes for burns wounds are two research hotspots in this field.

Nano-Delivery Revolution: Harnessing Mesenchymal Stem Cell-Derived Exosomes' Potential for Wound Healing

Stem cell transplantation has proven effective in treating acute and chronic wounds, but its limitations, such as low cellular viability and the need for specialized transportation, highlight the necessity for alternative approaches. This review explores the potential of engineered exosomes, containing identified miRNAs/peptides, as a more stable and efficient cell-free therapy for regenerative medicine, particularly in wound healing. The discussion emphasizes the benefits of exosomes, including their stability, reduced damage, and consistent biological activity, paving the way for innovative applications like lyophilized exosomes, mist spray delivery, and exosome-based scaffolds. The exploration of cell-free therapy in this review holds promising implications for advancing wound-healing strategies.

Recent trends on polycaprolactone as sustainable polymer-based drug delivery system in the treatment of cancer: Biomedical applications and nanomedicine

The unique properties-such as biocompatibility, biodegradability, bio-absorbability, low cost, easy fabrication, and high versatility-have made polycaprolactone (PCL) the center of attraction for researchers. The derived introduction in this manuscript gives a pretty detailed overview of PCL, so you can first brush up on it. Discussion on the various PCL-based derivatives involves, but is not limited to, poly(ε-caprolactone-co-lactide) (PCL-co-LA), PCL-g-PEG, PCL-g-PMMA, PCL-g-chitosan, PCL-b-PEO, and PCL-g-PU specific properties and their probable applications in biomedicine. This paper has considered examining the differences in the diverse disease subtypes and the therapeutic value of using PCL. Advanced strategies for PCL in delivery systems are also considered. In addition, this review discusses recently patented products to provide a snapshot of recent updates in this field. Furthermore, the text probes into recent advances in PCL-based DDS, for example, nanoparticles, liposomes, hydrogels, and microparticles, while giving special attention to comparing the esters in the delivery of bioactive compounds such as anticancer drugs. Finally, we review future perspectives on using PCL in biomedical applications and the hurdles of PCL-based drug delivery, including fine-tuning mechanical strength/degradation rate, biocompatibility, and long-term effects in living systems.

Gene-edited cells: novel allogeneic gene/cell therapy for epidermolysis bullosa

Epidermolysis bullosa (EB) is a group of rare genetic skin fragility disorders, which are hereditary. These disorders are associated with mutations in at least 16 genes that encode components of the epidermal adhesion complex. Currently, there are no effective treatments for this disorder. All current treatment approaches focus on topical treatments to prevent complications and infections. In recent years, significant progress has been achieved in the treatment of the severe genetic skin blistering condition known as EB through preclinical and clinical advancements. Promising developments have emerged in the areas of protein and cell therapies, such as allogeneic stem cell transplantation; in addition, RNA-based therapies and gene therapy approaches have also become a reality. Stem cells obtained from embryonic or adult tissues, including the skin, are undifferentiated cells with the ability to generate, maintain, and replace fully developed cells and tissues. Recent advancements in preclinical and clinical research have significantly enhanced stem cell therapy, presenting a promising treatment option for various diseases that are not effectively addressed by current medical treatments. Different types of stem cells such as primarily hematopoietic and mesenchymal, obtained from the patient or from a donor, have been utilized to treat severe forms of diseases, each with some beneficial effects. In addition, extensive research has shown that gene transfer methods targeting allogeneic and autologous epidermal stem cells to replace or correct the defective gene are promising. These methods can regenerate and restore the adhesion of primary keratinocytes in EB patients. The long-term treatment of skin lesions in a small number of patients has shown promising results through the transplantation of skin grafts produced from gene-corrected autologous epidermal stem cells. This article attempts to summarize the current situation, potential development prospects, and some of the challenges related to the cell therapy approach for EB treatment.

Emerging technologies in regenerative medicine: The future of wound care and therapy

Wound healing, an intricate biological process, comprises orderly phases of simple biological processed including hemostasis, inflammation, angiogenesis, cell proliferation, and ECM remodeling. The regulation of the shift in these phases can be influenced by systemic or environmental conditions. Any untimely transitions between these phases can lead to chronic wounds and scarring, imposing a significant socio-economic burden on patients. Current treatment modalities are largely supportive in nature and primarily involve the prevention of infection and controlling inflammation. This often results in delayed healing and wound complications. Recent strides in regenerative medicine and tissue engineering offer innovative and patient-specific solutions. Mesenchymal stem cells (MSCs) and their secretome have gained specific prominence in this regard. Additionally, technologies like tissue nano-transfection enable in situ gene editing, a need-specific approach without the requirement of complex laboratory procedures. Innovating approaches like 3D bioprinting and ECM bioscaffolds also hold the potential to address wounds at the molecular and cellular levels. These regenerative approaches target common healing obstacles, such as hyper-inflammation thereby promoting self-recovery through crucial signaling pathway stimulation. The rationale of this review is to examine the benefits and limitations of both current and emerging technologies in wound care and to offer insights into potential advancements in the field. The shift towards such patient-centric therapies reflects a paradigmatic change in wound care strategies.

Exploring the therapeutic potential of different sources of mesenchymal stem cells: a novel approach to combat burn wound infections

The most prevalent and harmful injuries are burns, which are still a major global health problem. Burn injuries can cause issues because they boost the inflammatory and metabolic response, which can cause organ malfunction and systemic failure. On the other hand, a burn wound infection creates an environment that is conducive to the growth of bacteria and might put the patient at risk for sepsis. In addition, scarring is unavoidable, and this results in patients having functional and cosmetic issues. Wound healing is an amazing phenomenon with a complex mechanism that deals with different types of cells and biomolecules. Cell therapy using stem cells is one of the most challenging treatment methods that accelerates the healing of burn wounds. Since 2000, the use of mesenchymal stem cells (MSCs) in regenerative medicine and wound healing has increased. They can be extracted from various tissues, such as bone marrow, fat, the umbilical cord, and the amniotic membrane. According to studies, stem cell therapy for burn wounds increases angiogenesis, has anti-inflammatory properties, slows the progression of fibrosis, and has an excellent ability to differentiate and regenerate damaged tissue. Figuring out the main preclinical and clinical problems that stop people from using MSCs and then suggesting the right ways to improve therapy could help show the benefits of MSCs and move stem cell-based therapy forward. This review's objective was to assess mesenchymal stem cell therapy's contribution to the promotion of burn wound healing.

Latest advance anti-inflammatory hydrogel wound dressings and traditional Lignosus rhinoceros used for wound healing agents

Wound healing is a physiological process occurring after the onset of a skin lesion aiming to reconstruct the dermal barrier between the external environment and the body. Depending on the nature and duration of the healing process, wounds are classified as acute (e.g., trauma, surgical wounds) and chronic (e.g., diabetic ulcers) wounds. The latter, often affect millions of people globally, take months to heal or not heal non-healing chronic wounds, are typically susceptible to microbial infection, and are a major cause of morbidity. Wounds can be treated with a variety of non-surgical (topical formulations, wound dressings) and surgical (debridement, skin grafts/flaps) methods. Three-dimensional (3D)-(bio) printing and traditional wound dressings are two examples of modern experimental techniques. This review focuses on several types of anti-inflammatory wound dressings, especially focusing on hydrogels and traditional macro-fungi like L. rhinocerotis as agents that promote wound healing. In this study, we introduced novel anti-inflammatory hydrogel dressings and offered innovative methods for application and preparation to aid in the healing. Additionally, we summarize the key elements required for wound healing and discuss our analysis of potential future issues. These findings suggest that L. rhinocerotis and various anti-inflammatory hydrogels can be considered as conventional and alternative macro-fungi for the treatment of non-communicable diseases. We summarized the development of functional hydrogel dressings and traditional Lignosus rhinoceros used for wound healing agents in recent years, as well as the current situation and future trends, in light of their preparation mechanisms and functional effects.

Sequential Bone Repair in Rabbit Sinus Lifts Using Bio-Oss and Hyaluronic Acid-Polynucleotide Gel (Regenfast)

BACKGROUND

A comprehensive investigation to associate the use of polynucleotides and hyaluronic acid with bovine bone in maxillary sinus lift procedures in rabbits has not been performed yet. The aim was to evaluate the influence of this novel association on the processes of bone regeneration in maxillary sinus augmentation.

METHODS

In this prospective, randomized, within-animal model, maxillary sinus augmentation was performed bilaterally in 12 rabbits. Deproteinized bovine bone material (DBBM) was used as filler material. A hyaluronic acid-polynucleotide gel was aggregated at the test site. Histological evaluations were performed after 2 and 10 weeks of healing.

RESULTS

After 2 weeks of healing, similar amounts of new bone were observed at both the control (7.7 ± 4.3%) and test sites (8.1 ± 3.8%; p = 0.697). Bone formation was observed predominantly along the osteotomy margins and adjacent sinus walls. After 10 weeks of healing, the total new bone fraction reached 28.0 ± 10.1% at the control sites and 27.3 ± 10.5% at the test sites (p = 0.563). Multiple perforations of the sinus mucosa were observed in both groups when in contact with the biomaterial granules.

CONCLUSION

The present study failed to demonstrate a positive effect on bone formation when incorporating hyaluronic acid-polynucleotide gel (Regenfast) into a xenograft for maxillary sinus augmentation. Additionally, the use of this gel did not mitigate the occurrence of thinned mucosa or reduce the risk of subsequent sinus mucosa perforation.

Diabetic rats skin wounds treated with heterologous fibrin sealant followed by photobiomodulation therapy

Diabetes mellitus is characterized by elevated blood glucose levels causing sometimes impairment of the body's ability to repair itself. Promising treatments for tissue repair have included photobiomodulation therapy and heterologous fibrin biopolymer (HFB). This study aimed to evaluate the impact of photobiomodulation therapy by LED, both as a standalone treatment and in conjunction with heterologous fibrin biopolymer in treatment of skin lesions of diabetic rats. Diabetes was induced using alloxan. Full-thickness skin wounds were induced on the backs of 56 Wistar rats, which were randomly allocated into four groups: control group, heterologous fibrin biopolymer group, photobiomodulation therapy by LED group, and photobiomodulation therapy by LED combined with heterologous fibrin biopolymer group. The treatments spanned two experimental periods, lasting 7 and 14 days. Notably, the HFB group exhibited results similar to those of the LED group concerning wound regression, while demonstrating superior resistance to healing. Interestingly, the LED + HFB group showed greater skin damage at 7 days, but an improved repair process at 14 days compared to the control group. The findings indicate that combining photobiomodulation by LED with HFB did not enhance wound healing in diabetic rats beyond the effects of each treatment alone. Both treatments were effective individually, with HFB showing particular strength in promoting collagen maturation and improving tissue biomechanical properties. This study contributes to the ongoing body of research on skin repair with this innovative HFB. Future clinical trials will be essential to validate this proposition.

Recent advances in mesoporous silica nanoparticles formulations and drug delivery for wound healing

Wound healing is a natural process that can be disrupted by disease. Nanotechnology is a promising platform for the development of new therapeutic agents to accelerate acute and chronic wound healing. Drug delivery by means of nanoparticles as well as wound dressings have emerged as suitable options to improving the healing process. The characteristics of mesoporous silica nanoparticles (MSNs) make them efficient carriers of pharmaceutical agents alone or in combination with dressings. In order to maximize the effect of a drug and minimize its adverse consequences, it may be possible to include targeted and intelligent release of the drug into the design of MSNs. Its use to facilitate closure of adjacent sides of a cut as a tissue adhesive, local wound healing, controlled drug release and induction of blood coagulation are possible applications of MSNs. This review summarizes research on MSN applications for wound healing. It includes a general overview, wound healing phases, MSN formulation, therapeutic possibilities of MSNs and MSN-based drug delivery systems for wound healing.

Enhancing the wound healing potential using earthworm clitellum factors and elucidating its molecular mechanism in an in-vitro and earthworm model

Earthworm, Eudrilus eugeniae cannot survive and regenerate without clitellum segments. In regenerating worms, the clitellum's epithelial and circular muscular layers are reduced to one-third, and longitudinal cell layers to half. In C2C12 cells, Clitellum Factors (CF - 5, 25 and 50%) and Regenerative Clitellum Factors (RCF - 5, 25, 50, 75%) ameliorate the cell viability up to 20-28% and 30-38% respectively than the control. In contrast, extracts from body segments negatively influence cell viability up to 80%. In a scratch-wound assay, 25% RCF and 5% CF achieved 99.86% and 81.54% wound closure in 24 h, respectively, compared to 40% in controls. RCF and CF also possess enhanced anti-microbial activity against gram + ve bacteria. Western Blotting reveals that Wnt3a, HoxD3 and VEGF were remarkably upregulated in RCF and CF treated samples and their upregulated stemness property is effectively regulated by p53, TCTP, H2AX, Cleaved Caspase-3 proteins. Immunofluorescence data clearly states that Wnt3a and Caspase-3 signals are more profoundly observed in nuclear over cytoplasm in RCF treated samples and H2AX shows less nuclear signals than CF. In in-vivo earthworm model conditions, RCF remarkably promotes the survivability and wound healing ability by promoting the Wnt3a and VEGF expression together with downregulation of Cox2.

The impact of subdermal adipose derived stem cell injections and early excision on systemic oxidative stress and wound healing in rats with severe scald burns

AIM

This study aims to develop an experimental treatment model effective against oxidative stress in the acute period of severe burns and to analyze the mechanisms of healing large wound defects.

METHODS

Five rats, including 2 females and 3 males, were used as donors to obtain adipose-derived stem cells (ADSC) from the inguinal fat pad. The stem cells were labeled with green fluorescent protein. The study included four groups of 17 rats, each with grade 3 scalding burns on 30 % of their body surface, and a control group of 10 rats with an equal number of males and females. After early excision, 106 ADSC-derived stem cells were administered subdermally to the burned wound and autografted to the stem cell group (n = 17). The early excision group (n = 17) received early excision and autograft, with 2 ml of normal saline injected subdermally into the burn wound edge. The PLM group (n = 17) was treated with a polylactic membrane (PLM) dressing after the burn. No treatment was given to the burn group (n = 17). Ten rats from all groups were sacrificed on the 4th day post-burn for oxidative stress evaluation. The control group (n = 10) was sacrificed on day 4. Blood and tissue samples were collected post-sacrifice. Oxidative stress and inflammation in the blood, as well as cell damage in the skin, liver, kidneys, and lungs, were investigated histopathologically and biochemically on the 4th day post-burn. On the 70th day after burn, wound healing was examined macroscopically and histopathologically.

RESULTS

On the 4th day, oxidative stress results showed that the levels of Total Oxidative Capacity (TOC) in the blood were lowest in the stem cell (7.4 [6-8.8]), control (6.7 [5.9-7.6]), and early excision (7.5 [6.6-8.5]) groups, with no significant difference between them. The burn group (14.7 [12.5-16.9]) had the highest TOC levels. The PLM group (9.7 [8.6-10.7]) had lower TOC levels than the burn group but higher levels than the other groups. Histopathological examination on the 4th day revealed low liver caspase-3 immunoreactivity in the stem cell and early excision groups among the burn groups. Caspase-3 immunoreactivity levels were as follows: stem cell group (20 [10-30]), early excision group (25 [15-50]), PLM group (70 [50-100]), control group (0), and burn group (80 [60-120]). Other oxidative stress and end-organ damage outcomes were consistent with these results. All rats in the stem cell group had burn wounds that healed completely by the 70th day. Examination of the skin and its appendages from the stem cell group with an immunofluorescence microscope demonstrated green coloration, indicating incorporation of stem cells.

CONCLUSION

Stem cells may have the potential to form new skin and its appendages, providing better healing for large skin defects. Early excision treatment, by removing local necrotic tissues after extensive and deep burns, can prevent end-organ damage due to systemic oxidative stress and inflammation. We also believe that when these two treatments are used together, they can achieve the best results.

Chitosan-based hydrogel dressings with antibacterial and antioxidant for wound healing

Bacterial infection and free radical oxidative stress at the wound site could easily cause cascade inflammation and hinder the healing process of the wound. In this study, chitosan-cysteine-gallic acid (CCG) hydrogel with antibacterial and antioxidant properties was synthesized by chitosan (CS), cysteine (Cys), and gallic acid (GA) for a preliminary evaluation of its therapeutic efficacy in a mouse model of full-layer skin defect. In vitro analysis showed that the CCG hydrogel had good antibacterial activity and blood compatibility. In vivo, the CCG hydrogel wound dressings accelerated wound healing, stimulate angiogenesis, increase collagen deposition and anti-inflammatory factor expression. The CCG hydrogel wound dressing is designed to promote the regeneration of damaged skin tissue and is expected to become a potential candidate for clinical treatment.

Beneficial effects of adipose-derived stromal vascular fraction on testicular injury caused by busulfan

The use of stem cells can attenuate testicular injury and promote sperm production. The adipose-derived stromal vascular fraction (SVF) has become an attractive cell source for cell-based therapies. In this study, we aimed to investigate the therapeutic efficacy of SVF on busulfan-induced testicular damage in rats. Twenty-four male rats were randomly divided into control, busulfan, SVF, and busulfan + SVF groups. Testicular damage was induced by intraperitoneal administration of busulfan (35 mg/kg). SVF obtained from human adipose tissue using Lipocube SVF™ was injected into rats 5 weeks after busulfan administration. At the end of the 8th week, rats were sacrificed, and histopathological, biochemical, and western blotting analyses were performed. No harmful effects of SVF on healthy testis tissue and sperm parameters were detected. SVF improved busulfan-induced oxidative stress in both testis tissue and serum. SVF injection to damaged testicular tissue resulted in increases in the healthy spermatozoon numbers and decreases in the abnormal tail numbers. Additionally, SVF increased bax/Bcl, DAZL, and TGF-β1 levels whereas decreased ATG5 and NF-kB levels. According to the results we obtained in this study, we suggest that SVF is beneficial in restoring damaged tissue by primarily being a multipotent cell source, by inhibiting oxidative stress and converting necrotic cell death to apoptotic cell death. In the future, clinical applications should bring higher benefits. Since SVF is the patient's own tissue, being harmless, it will offer an advantageous supportive treatment option for patients already weakened by cancer and anticancer therapy.

Temperature-responsive self-contraction nanofiber/hydrogel composite dressing facilitates the healing of diabetic-infected wounds

Bacterial infections and long-term inflammation cause serious secondary damage to chronic diabetic wounds and hinder the wound healing processes. Currently, multifunctional hydrogels have shown promising effects in chronic wound repair. However, traditional hydrogels only keep the wound moist and protect it from bacterial infection, and cannot provide mechanical force to contract the wound edges to achieve facilitated wound closure. Here, an asymmetric composite dressing was created by combining biaxially oriented nanofibers and hydrogel, inspired by the double-layer structure of the traditional Chinese medicinal plaster patch, for managing chronic wounds. Specifically, electrospun Poly-(lactic acid-co-trimethylene carbonate) (PLATMC) nanofibers and methacrylate gelatin (GelMa) hydrogel loaded with Epinecidin-1@chitosan (Epi-1@CS) nanoparticles are assembled as the temperature-responsive self-contracting nanofiber/hydrogel (TSNH) composite dressing. The substrate layer of PLATMC nanofibers combines topological morphology with material properties to drive wound closure through temperature-triggered contraction force. The functional layer of GelMa hydrogel is loaded with Epi-1@CS nanoparticles that combine satisfactory cytocompatibility, and antioxidant, anti-inflammatory, and antibacterial properties. Strikingly, in vivo, the TSNH dressing could regulate the diabetic wound microenvironment, thereby promoting collagen deposition, facilitating angiogenesis, and reducing the inflammatory response, which promotes the rapid healing of chronic wounds. This study highlights the potential of synergizing mechanical and biochemical signals in enhancing chronic wound treatment. Overall, this TSNH composite dressing is provided as a reliable approach to solving the long-standing problem of chronically infected wound healing.

The Angiogenic Repertoire of Stem Cell Extracellular Vesicles: Demystifying the Molecular Underpinnings for Wound Healing Applications

Stem cells-derived extracellular vesicles (SC-EVs) have emerged as promising therapeutic agents for wound repair, recapitulating the biological effects of parent cells while mitigating immunogenic and tumorigenic risks. These EVs orchestrate wound healing processes, notably through modulating angiogenesis-a critical event in tissue revascularization and regeneration. This study provides a comprehensive overview of the multifaceted mechanisms underpinning the pro-angiogenic capacity of EVs from various stem cell sources within the wound microenvironment. By elucidating the molecular intricacies governing their angiogenic prowess, we aim to unravel the mechanistic repertoire underlying their remarkable potential to accelerate wound healing. Additionally, methods to enhance the angiogenic effects of SC-EVs, current limitations, and future perspectives are highlighted, emphasizing the significant potential of this rapidly advancing field in revolutionizing wound healing strategies.

Sustained release of stem cell secretome from nano-villi chitosan microspheres for effective treatment of atopic dermatitis

Canine atopic dermatitis (AD) arises from hypersensitive immune reactions. AD symptoms entail severe pruritus and skin inflammation, with frequent relapses. Consequently, AD patients require continuous management, imposing financial burdens and mental fatigue on pet owners. In this study, we aimed to investigate the therapeutic relevance of secretome from canine adipose tissue-derived mesenchymal stem cells (MSCs), especially after encapsulation in nano-villi chitosan microspheres (CS-MS) to expect improved efficacy. Conditioned media (CM) from MSCs significantly inhibited the proliferation of splenocytes, induced the generation of regulatory T cells, and decreased mast cell degranulation. We found that beneficial soluble factors known to reduce AD symptoms, including transforming growth factor-beta 1, were detectable after sequential concentration and lyophilization of CM. The CS-MS, developed by a phase inversion regeneration method, showed high loading and sustained release of the secretome. Local injection of secretome-loaded CS-MS (ST/SC-MS) effectively reduced clinical severity compared to groups treated with secretome. Histological analysis revealed that ST/SC-MS potently suppressed epidermal hyperplasia, immunocyte infiltration and mast cell activation in the lesion. Taken together, this study presents a novel therapeutic approach exhibiting more potent and prolonged immunoregulatory efficacy of MSC secretome for canine AD treatment.

Unveiling advanced strategies for therapeutic stem cell interventions in severe burn injuries: a comprehensive review

This comprehensive review explores the complex terrain of stem cell therapies as a potential therapeutic frontier in the healing of complicated burn wounds. Serious tissue damage, impaired healing processes, and possible long-term consequences make burn wounds a complex problem. An in-depth review is required since, despite medical progress, existing methods for treating severe burn wounds have significant limitations. Burn wounds are difficult to heal because they cause extensive tissue damage. The challenges of burn injury-induced tissue regeneration and functional recovery are also the subject of this review. Although there is a lot of promise in current stem cell treatments, there are also some limitations with scalability, finding the best way to transport the cells, and finding consistent results across different types of patients. To shed light on how to improve stem cell interventions to heal severe burn wounds, this review covers various stem cell applications in burn wounds and examines these obstacles. To overcome these obstacles, one solution is to enhance methods of stem cell distribution, modify therapies according to the severity of the burn, and conduct more studies on how stem cell therapy affects individual patients. Novel solutions may also be possible through the combination of cutting-edge technologies like nanotechnology and biotechnology. This review seeks to increase stem cell interventions by analyzing present challenges and suggesting strategic improvements. The goal is to provide a more effective and tailored way to repair serious burn wounds.

The role of adipose tissue-derived stromal cells, macrophages and bioscaffolds in cutaneous wound repair

Skin healing is a complex and dynamic physiological process that follows mechanical alteration of the skin barrier. Under normal conditions, this complex process can be divided into at least three continuous and overlapping phases: an inflammatory reaction, a proliferative phase that leads to tissue reconstruction and a phase of tissue remodeling. Macrophages critically contribute to the physiological cascade for tissue repair. In fact, as the inflammatory phase progresses, macrophage gene expression gradually shifts from pro-inflammatory M1-like to pro-resolutive M2-like characteristics, which is critical for entry into the repair phase. A dysregulation in this macrophage' shift phenotype leads to the persistence of the inflammatory phase. Mesenchymal stromal cells and specifically the MSC-derived from adipose tissue (ADSCs) are more and more use to treat inflammatory diseases and several studies have demonstrated that ADSCs promote the wound healing thanks to their neoangiogenic, immunomodulant and regenerative properties. In several studies, ADSCs and macrophages have been injected directly into the wound bed, but the delivery of exogenous cells directly to the wound raise the problem of cell engraftment and preservation of pro-resolutive phenotype and viability of the cells. Complementary approaches have therefore been explored, such as the use of biomaterials enriched with therapeutic cell to improve cell survival and function. This review will present a background of the current scaffold models, using adipose derived stromal-cells and macrophage as therapeutic cells for wound healing, through a discussion on the potential impact for future applications in skin regeneration. According to the PRISMA statement, we resumed data from investigations reporting the use ADSCs and bioscaffolds and data from macrophages behavior with functional biomaterials in wound healing models. In the era of tissue engineering, functional biomaterials, that can maintain cell delivery and cellular viability, have had a profound impact on the development of dressings for the treatment of chronic wounds. Promising results have been showed in pre-clinical reports using ADSCs- and macrophages-based scaffolds to accelerate and to improve the quality of the cutaneous healing.

Deciphering Collagen Phenotype Dynamics Regulators: Insights from In-Silico Analysis

Collagen (Col) types I and III are integral components in wound healing and tissue regeneration, influencing tissue development, homeostasis, and related pathologies. Col I and Col III expression changes during different stages of wound healing and understanding the regulation of collagen phenotype determination is crucial for unraveling the complexities of these processes. Transcription factors and microRNAs, directly and indirectly, play a critical role in regulating collagen expression, however, a comprehensive understanding of the factors regulating Col I and III phenotypes remains elusive. This critically analyzed published reports with focuses on various factors regulating the expression of Col I and Col III at the transcriptional and translational levels. We performed bioinformatics analysis with an input of proinflammatory mediators, growth factors, elastases, and matrix metalloproteinases and predicted transcription factors and microRNAs involved in the regulation of collagen expression. Network analysis revealed an interaction between genes, transcription factors, and microRNAs and provided a holistic view of the regulatory landscape governing collagen expression and unveils intricate interconnections. This analysis lays a founda-tional framework for guiding future research and therapeutic interventions to promote extracellular matrix remodeling, wound healing, and tissue regeneration after an injury by modulating collagen expression. In essence, this scientific groundwork offers a comprehensive exploration of the regulatory dynamics in collagen synthesis, serving as a valuable resource for advancing both basic research and clinical interventions in tissue repair.

Advancements in diabetic foot ulcer research: Focus on mesenchymal stem cells and their exosomes

Diabetes represents a widely acknowledged global public health concern. Diabetic foot ulcer (DFU) stands as one of the most severe complications of diabetes, its occurrence imposing a substantial economic burden on patients, profoundly impacting their quality of life. Despite the deepening comprehension regarding the pathophysiology and cellular as well as molecular responses of DFU, the current therapeutic arsenal falls short of efficacy, failing to offer a comprehensive remedy for deep-seated chronic wounds and microvascular occlusions. Conventional treatments merely afford symptomatic alleviation or retard the disease's advancement, devoid of the capacity to effectuate further restitution of compromised vasculature and nerves. An escalating body of research underscores the prominence of mesenchymal stem cells (MSCs) owing to their paracrine attributes and anti-inflammatory prowess, rendering them a focal point in the realm of chronic wound healing. Presently, MSCs have been validated as a highly promising cellular therapeutic approach for DFU, capable of effectuating cellular repair, epithelialization, granulation tissue formation, and neovascularization by means of targeted differentiation, angiogenesis promotion, immunomodulation, and paracrine activities, thereby fostering wound healing. The secretome of MSCs comprises cytokines, growth factors, chemokines, alongside exosomes harboring mRNA, proteins, and microRNAs, possessing immunomodulatory and regenerative properties. The present study provides a systematic exposition on the etiology of DFU and elucidates the intricate molecular mechanisms and diverse functionalities of MSCs in the context of DFU treatment, thereby furnishing pioneering perspectives aimed at harnessing the therapeutic potential of MSCs for DFU management and advancing wound healing processes.

Advancements in cell-based therapies for thermal burn wounds: a comprehensive systematic review of clinical trials outcomes

BACKGROUND

Burn trauma is one of the major causes of morbidity and mortality worldwide. The standard management of burn wounds consists of early debridement, dressing changes, surgical management, and split-thickness skin autografts (STSGs). However, there are limitations for the standard management that inclines us to find alternative treatment approaches, such as innovative cell-based therapies. We aimed to systematically review the different aspects of cell-based treatment approaches for burn wounds in clinical trials.

METHODS

A systematic search through PubMed, Medline, Embase, and Cochrane Library databases was carried out using a combination of keywords, including "Cell transplantation", "Fibroblast", "Keratinocyte", "Melanocyte", or "Stem Cell" with "Burn", "Burn wound", or "Burn injury". Firstly, titles and abstracts of the studies existing in these databases until "February 2024" were screened. Then, the selected studies were read thoroughly, and considering the inclusion and exclusion criteria, final articles were included in this systematic review. Moreover, a manual search was performed through the reference lists of the included studies to minimize the risk of missing reports.

RESULTS

Overall, 30 clinical trials with 970 patients were included in our study. Considering the type of cells, six studies used keratinocytes, nine used fibroblasts, eight used combined keratinocytes and fibroblasts, one study used combined keratinocytes and melanocytes, five used combined keratinocytes and fibroblasts and melanocytes, and one study used mesenchymal stem cells (MSCs). Evaluation of the preparation type in these studies showed that cultured method was used in 25 trials, and non-cultured method in 5 trials. Also, the graft type of 17 trials was allogeneic, and of 13 other trials was autologous.

CONCLUSIONS

Our study showed that employing cell-based therapies for the treatment of burn wounds have significant results in clinical studies and are promising approaches that can be considered as alternative treatments in many cases. However, choosing appropriate cell-based treatment for each burn wound is essential and depends on the situation of each patient.

CD146-dependent macrophage infiltration promotes epidural fibrosis via the Erdr1/ERK/CCR2 pathway

Low back pain due to epidural fibrosis is a major complication after spine surgery. Macrophages infiltrate the wound area post laminectomy, but the role of macrophages in epidural fibrosis remains largely elusive. In a mouse model of laminectomy, macrophage depletion decreased epidural fibrosis. CD146, an adhesion molecule involved in cell migration, is expressed by macrophages. CD146-defective macrophages exhibited impaired migration, which was mediated by reduced expression of CCR2 and suppression of the MAPK/ERK signaling pathway. CD146-defective macrophages suppress the MAPK/ERK signaling pathway by increasing Erdr1. In vivo, CD146 deficiency decreased macrophage infiltration and reduced extracellular matrix deposition in wound tissues. Moreover, the anti-CD146 antibody AA98 suppressed macrophage infiltration and epidural fibrosis. Taken together, these findings demonstrated that CD146 deficiency alleviates epidural fibrosis by decreasing the migration of macrophages via the Erdr1/ERK/CCR2 pathway. Blocking CD146 and macrophage infiltration may help alleviate epidural fibrosis.

Electrospun nanofibrous wound dressings with enhanced efficiency through carbon quantum dots and citrate incorporation

Nanofibers show promise for wound healing by facilitating active agent delivery, moisture retention, and tissue regeneration. However, selecting suitable dressings for diverse wound types and managing varying exudate levels remains challenging. This study synthesized carbon quantum dots (CQDs) from citrate salt and thiourea using a hydrothermal method. The CQDs displayed antibacterial activity against Staphylococcus aureus and Escherichia coli. A nanoscaffold comprising gelatin, chitosan, and polycaprolactone (GCP) was synthesized and enhanced with silver nanoparticle-coated CQDs (Ag-CQDs) to form GCP-Q, while citrate addition yielded GCP-QC. Multiple analytical techniques, including electron microscopy, FT-IR spectroscopy, dynamic light scattering, UV-Vis, photoluminescence, X-ray diffraction, porosity, degradability, contact angle, and histopathology assessments characterized the CQDs and nanofibers. Integration of CQDs and citrate into the GCP nanofibers increased porosity, hydrophilicity, and degradability-properties favorable for wound healing. Hematoxylin and eosin staining showed accelerated wound closure with GCP-Q and GCP-QC compared to GCP alone. Overall, GCP-Q and GCP-QC nanofibers exhibit significant potential for skin tissue engineering applications.

Magneto-responsive biocomposites in wound healing: from characteristics to functions

The number of patients with non-healing wounds continuously increases, and has become a prominent societal issue that imposes a heavy burden on both patients and the entire healthcare system. Although traditional dressings play an important role in wound healing, the complexity and diversity of the healing process pose serious challenges in this field. Magneto-responsive biocomposites, with their excellent biocompatibility, remote spatiotemporal controllability, and unique convenience, demonstrate enticing advantages in the field of wound dressings. However, current research on magneto-responsive biocomposites as wound dressings lacks comprehensive and in-depth reviews, which to some extent, restricts the deeper understanding and further development of this field. Based on this, this paper reviews the latest advances in magnetic responsive wound dressings for wound healing. First, we review the process of skin wound healing and parameters for assessing repair progress. Then, we systematically discuss the preparation strategies and unique characteristics of magneto-responsive biocomposites, focusing on magneto-induced orientation, magneto-induced mechanical stimulation, and magnetocaloric effect. Subsequently, this review elaborates the multiple mechanisms of magneto-responsive biocomposites in promoting wound healing, including regulating cell behavior, enhancing electrical signal, controlling drug release, and accelerating tissue reconstruction. Finally, we further propose the development direction and future challenges of magnetic responsive biomaterials as wound dressings in clinical application.

Towards the development of sensation-enabled skin substitutes

Recent advances in cell and biofabrication technologies have contributed to the development of complex human organs. In particular, several skin substitutes are being generated using tissue engineering and regenerative medicine (TERM) technologies. However, recent studies mainly focus on the restoration of the dermis and epidermis layers rather than the regeneration of a fully functional innervated skin organ. Innervation is a critical step in functional tissue repair which has been overlooked in the current TERM studies. In the current study, we highlight the importance of sensation in the skin as the largest sensory organ in the human body. In large non-healing skin wounds, the skin sensation is severely diminished or completely lost and ultimately lead to chronic pain and wound healing process interruption. Current therapeutics for restoring skin sensation after trauma are limited. Recent regenerative medicine-based studies could successfully induce neural networks in skin substitutes, but the effectiveness of these technologies in enhancing sensory capability needs further investigation.

Phytoconstituents as modulators of NF-κB signalling: Investigating therapeutic potential for diabetic wound healing

The NF-κB pathway plays a pivotal role in impeding the diabetic wound healing process, contributing to prolonged inflammation, diminished angiogenesis, and reduced proliferation. In contrast to modern synthetic therapies, naturally occurring phytoconstituents are well-studied inhibitors of the NF-κB pathway that are now attracting increased attention in the context of diabetic wound healing because of lower toxicity, better safety and efficacy, and cost-effectiveness. This study explores recent research on phytoconstituent-based therapies and delve into their action mechanisms targeting the NF-κB pathway and potential for assisting effective healing of diabetic wounds. For this purpose, we have carried out surveys of recent literature and analyzed studies from prominent databases such as Science Direct, Scopus, PubMed, Google Scholar, EMBASE, and Web of Science. The classification of phytoconstituents into various categorie such as: alkaloids, triterpenoids, phenolics, polyphenols, flavonoids, monoterpene glycosides, naphthoquinones and tocopherols. Noteworthy phytoconstituents, including Neferine, Plumbagin, Boswellic acid, Genistein, Luteolin, Kirenol, Rutin, Vicenin-2, Gamma-tocopherol, Icariin, Resveratrol, Mangiferin, Betulinic acid, Berberine, Syringic acid, Gallocatechin, Curcumin, Loureirin-A, Loureirin-B, Lupeol, Paeoniflorin, and Puerarin emerge from these studies as promising agents for diabetic wound healing through the inhibition of the NF-κB pathway. Extensive research on various phytoconstituents has revealed how they modulate signalling pathways, including NF-κB, studies that demonstrate the potential for development of therapeutic phytoconstituents to assist healing of chronic diabetic wounds.

Motion-Accommodating Dual-Layer Hydrogel Dressing to Deliver Adipose-Derived Stem Cells to Wounds

BACKGROUND

Current dressing materials cannot secure a cell survival-promoting wound environment for stem cell delivery due to insufficient assimilation to skin motion. The authors developed a novel motion-accommodating dual-layer hydrogel dressing for stem cell delivery into such wounds.

METHODS

Dorsal hand skin movement was evaluated to determine the potential range of deformation for a dressing. The outer hydrogel (OH) was fabricated with an alginate-acrylamide double-network hydrogel with a covalently cross-linked elastomer coat. The tough adhesive consisted of a chitosan-based bridging polymer and coupling reagents. OH material properties and adhesiveness on porcine skin were measured. An oxidized alginate-based inner hydrogel (IH) containing human adipose-derived stem cells (ASCs) was evaluated for cell-supporting and cell-releasing properties. The OH's function as a secondary dressing, and dual-layer hydrogel cell delivery potential in wounds were assessed in a rodent model.

RESULTS

The dual-layer hydrogel consisted of OH and IH. The OH target range of deformation was up to 25% strain. The OH adhered to porcine skin, and showed significantly higher adhesion energy than common secondary dressings and endured 900 flexion-extension cycles without detachment. OH showed a similar moisture vapor transmission rate as moisture-retentive dressings. IH maintained embedded cell survival for three days with significant cell release on the contacting surface. OH showed less fibrotic wound healing than other secondary dressings in vivo. The dual-layer hydrogel successfully delivered ASCs into open wounds of nude mice (13 ± 3 cells/HPF).

CONCLUSIONS

The novel dual-layer hydrogel can accommodate patient movement and deliver ASCs into the wound bed by securing the wound microenvironment.

Exosomes derived from cord blood Treg cells promote diabetic wound healing by targeting monocytes

Chronic nonhealing diabetic wounds are a critical clinical challenge. Regulatory T cells (Tregs) are immunosuppressive modulators affecting wound healing progression by controlling the inflammatory response. The current study attempted to investigate whether the exosomes derived from cord blood (CB) Tregs can accelerate the healing process. Exosomes were isolated from CB-Treg cultures using ultracentrifugation and validated with different specific markers of exosomes. The purified CB-Treg-derived exosomes were co-cultured with peripheral blood mononuclear cells (PBMCs) and CD14+ monocytes. The migration-promoting effect of CB-Treg-derived exosomes on fibroblasts and endothelial cells was investigated. We used thermosensitive Pluronic F-127 hydrogel (PF-127) loaded with CB-Treg-derived exosomes in a diabetic wound healing mouse model. CB-Treg-derived exosomes with 30-120 nm diameters revealed exosome-specific markers, such as TSG101, Alix, and CD63. CB-Treg-derived exosomes were mainly bound to the monocytes when co-cultured with PBMCs, and promoted monocyte polarization to the anti-inflammatory phenotype (M2) in vitro. CB-Treg-derived exosomes enhanced the migration of endothelial cells and fibroblasts. Furthermore, CB-Treg-derived exosomes treatment accelerated wound healing by downregulating inflammatory factor levels and upregulating the M2 macrophage ratio in vivo. Our findings indicated that CB-Treg-derived exosomes could be a promising cell-free therapeutic strategy for diabetic wound healing, partly by targeting monocytes.

Lignin-Based Antioxidant Hydrogel Patch for the Management of Atopic Dermatitis by Mitigating Oxidative Stress in the Skin

Atopic dermatitis (AD), a chronic skin condition characterized by itching, redness, and inflammation, is closely associated with heightened levels of endogenous reactive oxygen species (ROS) in the skin. ROS can contribute to the onset and progression of AD through oxidative stress, which leads to the release of proinflammatory cytokines, T-cell differentiation, and the exacerbation of skin symptoms. In this study, we aim to develop a therapeutic antioxidant hydrogel patch for the potential treatment of AD using lignin, a biomass waste material. Lignin contains polyphenol groups that enable it to scavenge ROS and exhibit antioxidant properties. The lignin hydrogel patches, possessing optimized mechanical properties through the control of the lignin and cross-linker ratio, demonstrated high ROS-scavenging capabilities. Furthermore, the lignin hydrogel demonstrated excellent biocompatibility with the skin, exhibiting beneficial properties in protecting human keratinocytes under high oxidative conditions. When applied to an AD mouse model, the hydrogel patch effectively reduced epidermal thickness in inflamed regions, decreased mast cell infiltration, and regulated inflammatory cytokine levels. These findings collectively suggest that lignin serves as a therapeutic hydrogel patch for managing AD by modulating oxidative stress through its ROS-scavenging ability.

Exploring the mechanistic role of silk sericin biological and chemical conjugates for effective acute and chronic wound repair and related complications

OBJECTIVE

The current review is designed to elaborate and reveal the underlying mechanism of sericin and its conjugates of drug delivery during wounds and wound-related issues.

SIGNIFICANCE

Wound healing is a combination of different humoral, molecular, and cellular mechanisms. Various natural products exhibit potential in wound healing but among them, sericin, catches much attention of researchers due to its bio-functional properties such as being biodegradable, biocompatible, anti-oxidant, anti-bacterial, photo-protector, anti-inflammatory and moisturizing agent.

METHODS AND RESULTS

Sericin triggers the activity of anti-inflammatory cytokines which decrease cell adhesion and promote epithelial cell formation. Moreover, sericin enhances the anti-oxidant enzymes in the wounded area which scavenge the toxic consequences of reactive species (ROS).

CONCLUSIONS

This article highlights the mechanisms of how topical administration of sericin formulations along with 4-hexylresorcinol,\Chitosan\Ag@MOF-GO, polyvinyl alcohol (PVA), platelet lysate and UV photo cross-linked hydrogel sericin methacrylate which recruits a large number of cytokines on wounded area that stimulate fibroblasts and keratinocyte production as well as collagen deposition that led to early wound contraction. It also reviews the different sericin-based nanoparticles that play a significant role in rapid wound healing.

Effect of 'Procumbenase' a serine protease from Tridax procumbens aqueous extract on wound healing: A scar free healing of full thickness wounds

Wound healing involves several cellular and molecular pathways. Tridax procumbens activates genetic pathways with antibacterial, antioxidant, anticancer, and anti-inflammatory properties, aiding wound healing. This study purified Procumbenase, a serine protease from T. procumbens extract, using gel filtration (Sephadex G-75) and ion exchange (CM-Sephadex C-50) chromatography. Characterization involved analyses of protease activity, RP-HPLC, SDS-PAGE, gelatin zymogram, PAS staining, mass spectrometry, and circular dichroism. Optimal pH and temperature were determined. Protease type was identified using inhibitors. Wound-healing potential was evaluated through tensile strength, wound models, hydroxyproline estimation, and NIH 3T3 cell scratch analysis. In incision wound rat models, Procumbenase increased tensile strength on day 14 more than saline and Povidone‑iodine. It increased wound contraction by 89 % after 10 days in excision wound models, attaining full contraction by day 15 and closure by day 21. Scarless wound healing was enhanced by 18 days of epithelialization against 22 and 21 days for saline and povidone‑iodine. Procumbenase increased hydroxyproline concentration 2.53-fold (59.93 ± 2.89 mg/g) compared to saline (23.67 ± 1.86 mg/g). In NIH 3 T3 cell scratch assay, Procumbenase increased migration by 60.93 % (50 μg) and 60.57 % (150 μg) after 48 h. Thus, Procumbenase is the primary bioactive molecule in T. procumbens, demonstrates scar-free wound healing properties.

Amniotic miracle: Investigating the unique development and applications of amniotic membrane in wound healing

BACKGROUND

The perfect repair of damaged skin has always been a constant goal for scientists; however, the repair and reconstruction of skin is still a major problem and challenge in injury and burns medicine. Human amniotic membrane (hAM), with its good mechanical properties and anti-inflammatory, antioxidant and antimicrobial benefits, containing growth factors that promote wound healing, has evolved over the last few decades from simple skin sheets to high-tech dressings, such as being made into nanocomposites, hydrogels, powders, and electrostatically spun scaffolds. This paper aims to explore the historical development, applications, trends, and research hotspots of hAM in wound healing.

METHODS

We examined 2660 publications indexed in the Web of Science Core Collection (WoSCC) from January 1, 1975 to July 12, 2023. Utilizing bibliometric methods, we employed VOSviewer, CiteSpace, and R-bibliometrix to characterize general information, identify development trends, and highlight research hotspots. Subsequently, we identified a collection of high-quality English articles focusing on the roles of human amniotic epithelial stem cells (hAESCs), human amniotic mesenchymal stem cells (hAMSCs), and amniotic membrane (AM) scaffolds in regenerative medicine and tissue engineering.

RESULTS

Bibliometric analysis identified Udice-French Research Universities as the most productive affiliation and Tseng S.C.G. as the most prolific author. Keyword analysis, historical direct quotations network, and thematic analysis helped us review the historical and major themes in this field. Our examination included the knowledge structure, global status, trends, and research hotspots regarding the application of hAM in wound healing. Our findings indicate that contemporary research emphasizes the preparation and application of products derived from hAM. Notably, both hAM and the cells isolated from it - hADSCs and hAESCs are prominent and promising areas of research in regenerative medicine and tissue engineering.

CONCLUSION

This research delivers a comprehensive understanding of the knowledge frameworks, global dynamics, emerging patterns, and primary research foci in the realm of hAM applications for wound healing. The field is rapidly evolving, and our findings offer valuable insights for researchers. Future research outcomes are anticipated to be applied in clinical practice, enhancing methods for disease prevention, diagnosis, and treatment.