Regeneration of Dermis: Scarring and Cells Involved

Human umbilical cord mesenchymal stem cell exosomes promote elastin production and acute skin wound healing via TGFβ1-Smad pathway

Skin wound healing is a complex physiological process influenced by multiple factors, including the patient's overall health status. Exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSC-Exos) have demonstrated significant potential in enhancing wound repair. This study investigates the mechanisms through which hUCMSC-Exos facilitate skin wound healing and evaluates their potential application in combination with hydrogels for clinical treatment. Human foreskin fibroblasts (HFF-1) were treated with varying concentrations of hUCMSC-Exos to evaluate their impact on cell proliferation, assessed via the CCK-8 assay. Exosome uptake by HFF-1 cells was visualized using PKH-26 dye staining, while flow cytometry was employed to analyze cell cycle changes. Cell migration was evaluated through scratch and Transwell assays. Gene expression levels of Collagen I, Elastin, and Fibronectin were quantified by qRT-PCR, while Elastin secretion was measured by ELISA. Western blotting was used to examine proteins in the TGFβ1-Smad signaling pathway. The role of SP1 in regulating Elastin gene expression was investigated by testing the SP1 inhibitor Plicamycin and examining hUCMSC-Exos ability to counteract its effect. Additionally, a chromatin immunoprecipitation (ChIP) assay was performed to analyze SP1 binding at the Elastin gene promoter. In vivo, the efficacy of hUCMSC-Exos combined with hydrogels in promoting wound healing was assessed using a mouse skin wound model. hUCMSC-Exos significantly enhanced HFF-1 cell proliferation at concentrations exceeding 1 × 10⁹ particles/mL and increased the proportion of cells in the S and G2/M phases. HFF-1 cells readily absorbed these exosomes, leading to improved cell migration. Treatment with hUCMSC-Exos upregulated the gene expression of Collagen I, Fibronectin, and Elastin. The SP1 inhibitor Plicamycin reduced Elastin gene expression, an effect that was reversed by hUCMSC-Exos. In vivo, the combination of hUCMSC-Exos and hydrogels accelerated wound healing, enhanced collagen organization, and promoted the formation of elastic fibers and blood vessels. hUCMSC-Exos facilitate skin wound healing by promoting SP1 binding to the Elastin gene promoter, thereby upregulating Elastin expression and supporting extracellular matrix remodeling. These findings suggest a promising therapeutic role for hUCMSC-Exos in clinical applications for wound healing.

Clinicopathologic Analysis of Dermatofibroma: A Retrospective Study of 165 Cases

Dermatofibroma (DF), also known as benign fibrous histiocytoma, is a common benign skin tumor whose clinicopathologic features and pathogenesis remain only partially understood. In this retrospective study, 165 cases of DF diagnosed between 2018 and 2024 were analyzed to characterize demographic, clinical, and histopathologic profiles. Data regarding patient age, gender, horizontal tumor size, anatomical location, and pathological subtypes were extracted from digital pathology archives. Statistical analyses revealed that male patients exhibited significantly larger horizontal tumor sizes compared to female patients (P = 0.027). Additionally, the tumor location was significantly associated with size, with lesions in the subcutaneous tissue showing larger mean horizontal dimensions than those in the reticular or papillary dermis (P = 0.032). These findings suggest that gender, tumor location, and pathological subtype are influential factors in DF growth, providing further insight into its clinical behavior and potential underlying mechanisms. These findings highlight the importance of considering patient gender and tumor location in the clinical management of DF, potentially guiding personalized treatment strategies and improving patient outcomes.

Highly expressed VGLL3 in keloid fibroblasts promotes glycolysis and collagen production via the activation of Wnt/β-catenin signaling

PURPOSE

This study investigated the effects and related mechanisms of Vestigial-like family member 3 (VGLL3) on keloid fibroblast (KF) proliferation, apoptosis, collagen production, and glycolysis.

METHODS

Western blot, qRT-PCR, and immunohistochemistry were used for determining VGLL3 expression. KF viability, proliferation, and apoptosis were assessed using CCK-8 assay, EdU assay, and flow cytometry. Changes in the protein expression levels of α-SMA, fibronectin, collagen I, and collagen III were examined utilizing western blotting. The pathways related to VGLL3 were analyzed using Gene Set Enrichment Analysis. Changes in glycolysis were assessed by measuring oxygen consumption rate (OCR), extracellular acidification rate (ECAR), glucose uptake, and lactate production. WNT2 and β-catenin protein levels were measured using western blotting.

RESULTS

VGLL3 was upregulated in human keloid tissues. In KFs, overexpression of VGLL3 inhibited cell apoptosis, promoted cell proliferation and protein expression of α-SMA, fibronectin, collagen I, and collagen III. Moreover, it reduced OCR level, and increased the levels of ECAR, glucose uptake, and lactate production. On the other hand, the knockdown of VGLL3 had the opposite effect. WNT2 and β-catenin protein levels were enhanced by overexpression of VGLL3 and reduced by VGLL3 knockdown. Silencing of WNT2 reversed the effects of VGLL3 on apoptosis, proliferation, collagen production, and glycolysis in KFs.

CONCLUSIONS

VGLL3 promoted glycolysis in KFs and keloid progression, which was achieved through the activation of Wnt signaling pathway. Therefore, targeting VGLL3 may be a promising therapeutic strategy for the treatment of keloids.

Chitosan-based structures for skin repair: A literature review

The use of chitosan in technological and biomedical applications has gained significant relevance due to its functional properties. Among its biological activities, its hemostatic, analgesic, antibacterial and anti-inflammatory activities make this natural biopolymer one of the most promising in the development of structures for skin repair. Its application and effects can be optimized by exploring efficient structuring techniques. In this context, this review is based on scientific evidence reported in the last decade regarding the development and use of chitosan-based structures in the skin repair process to show the most common structuring methods, the main mechanisms of action of chitosan, and its potential applications in skin repair processes. Additionally, this article brings a compilation of scientific and commercial works on the use of chitosan-based structures, in addition to vitro and/or in vivo results.

The regenerative wound healing effects and molecular mechanism of Isaria cicadae Miquel rice fermentation extract

Human skin wounds primarily heal through reparative wound healing without pilosebaceous units or other appendages, rather than regenerative wound healing. Hair follicle (HF) regeneration is a significant challenge for skin wound healing. The effects and underlying mechanisms of Isaria cicadae Miquel rice fermentation extract (IMFRE) remain unclear, although it has anti-inflammatory, antioxidant, and reparative effects on oxidative damage in keratinocytes. We assessed the regenerative wound healing ability of IMFRE and its related molecular mechanisms through experimental validation and network pharmacology analysis. Our findings suggest that IMFRE could be an important potential solution for regenerative wound healing of skin hair follicle by utilizing the Hippo pathway regulatory mechanism. KEY POINTS: • IMFRE was found to significantly enhance the wound healing rate of mouse skin. • CK15 and CD34 were significantly increased by high-dose IMFRE intervention. • IMFRE could inhibit EGFR, GPCR, and Integrin expression.

Umbilical Cord Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles Modulate Skin Matrix Synthesis and Pigmentation

Introduction

Research has unveiled the remarkable properties of extracellular vesicles derived from mesenchymal stromal cells (MSCs), particularly in promoting wound healing, aiding re-epithelialization, revitalizing aging skin, and inhibiting hyperpigmentation. However, investigations into the potential of small extracellular vesicles from umbilical cord-derived MSCs (UC-MSC-sEVs) in reducing scarring and preventing hyperpigmentation remain limited. Therefore, this study aims to evaluate the impact of UC-MSC-sEVs on the synthesis of the skin's extracellular matrix (ECM) and pigmentation using in vitro models.

Methods

The study investigated the impact of characterized UC-MSC-sEVs on various aspects including the proliferation, migration, antioxidant activity, and ECM gene expression of human dermal fibroblasts (HDF). Additionally, the effects of UC-MSC-sEVs on the proliferation, melanin content, and tyrosinase (TYR) activity of human melanoma cells (MNT-1) were examined. Furthermore, ex vivo models were employed to evaluate the skin permeation of PKH26-labelled UC-MSC-sEVs.

Results

The findings indicated that a high concentration of UC-MSC-sEVs positively influenced the proliferation of HDF. However, no changes in cell migration rate were observed. While the expressions of collagen type 1 and type 3 remained unaffected by UC-MSC-sEVs treatment, there were dose-dependent increases in the gene expressions of fibronectin, matrix metallopeptidase (MMP) 1, and MMP 3. Furthermore, UC-MSC-sEVs treatment did not impact the antioxidative superoxide dismutase (SOD) expression in HDF. Although UC-MSC-sEVs did not alter the proliferation of MNT-1 cells, it did result in a dose-dependent reduction in melanin synthesis without affecting TYR activity. However, when it was applied topically, UC-MSC-sEVs failed to penetrate the skin barrier and remained localized within the stratum corneum layer even after 18 hours.

Conclusion

These results highlight the potential of UC-MSC-sEVs in stimulating HDF proliferation, regulating ECM synthesis, and reducing melanin production. This demonstrates the promising application of UC-MSC-sEVs in medical aesthetics for benefits such as scar reduction, skin rejuvenation, and skin lightening.

Aberrant expression of messenger and small noncoding RNAomes in aged skin of rats

The exact mechanisms and key functional molecules involved in skin ageing remain largely unknown. Studies linking the expression of messenger RNAs (mRNAs) and small noncoding RNAs (sncRNAs) to skin ageing are limited. In this study, we performed RNA sequencing to assess the effects of ageing on the expression of mRNAs and sncRNAs in rat skin. Our results revealed that 241 mRNAs, 109 microRNAs (miRNAs), 20 piwi-interacting RNAs (piRNAs), 45 small nucleolar RNAs (snoRNAs), and 7 small nuclear RNAs (snRNAs) were significantly differentially expressed in the skin of aged rats compared to their younger counterparts. Histological validation using RT-qPCR further verified the significant differential expression of 13 mRNAs, 7 miRNAs, 2 piRNAs, 15 snoRNAs, and 1 snRNA. Additionally, several sncRNAs showed differential expression across various tissues, suggesting that they may have broad correlations with ageing. After establishing cellular senescence in skin fibroblasts, we identified 4 mRNAs, 4 miRNAs, and 10 snoRNAs that may mediate skin ageing by modulating fibroblast senescence. Notably, overexpression or knockdown of some differentially expressed RNAs in fibroblasts influenced cellular senescence, indicating that these RNAs could play an important role in the skin ageing process. These findings highlight their potential significance for future treatments of age-related skin disorders.

Piezoelectric nanocomposite electrospun dressings: Tailoring mechanics for scar-free wound recovery

Rational wound management and enhancing healing quality are critical in clinical practice. Electrical stimulation therapy (EST) has emerged as a valuable adjunctive treatment due to its safety and cost-effectiveness. Integrating piezoelectric materials into dressings offers a way to miniaturize and personalize electrotherapy, enhancing convenience. To address the impact of physical factors of dressings on wound healing, a nanocomposite piezoelectric electrospun dressing using poly(L-lactic acid) (PLLA) and barium titanate (BaTiO3) was developed. We intentionally exaggerated design flaws to mimic the characteristics of scar extracellular matrix (ECM), including the oriented thick fibers and high Young's modulus. Initially, these dressings promoted fibrosis and hindered functional regeneration. However, when the piezoelectric effect was triggered by ultrasound, the fibrotic phenotype was reversed, leading to scar-free healing with well-regenerated functional structures. This study highlights the significant therapeutic potential of piezoelectric dressings in skin wound treatment and underscores the importance of carefully designing the static physical properties of dressings for optimal efficacy.

MSC-EVs and UCB-EVs promote skin wound healing and spatial transcriptome analysis

Extracellular vesicles (EVs) are important paracrine mediators derived from various cells and biological fluids, including plasma, that are capable of inducing regenerative effects by transferring bioactive molecules such as microRNAs (miRNAs). This study investigated the effect of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) isolated from umbilical cord blood and human umbilical cord plasma-derived extracellular vesicles (UCB-EVs) on wound healing and scar formation reduction. Spatial transcriptomics (ST) was used to study the effects of MSC-EVs and UCB-EVs on the heterogeneity of major cell types and wound healing pathways in mouse skin tissue. MSC-EVs and UCB-EVs were isolated using ultracentrifugation and identified using transmission electron microscopy, nanoparticle tracking analysis, and western blot. The effects of MSC-EVs and UCB-EVs on human dermal fibroblast-adult cell (HDF-a) migration and proliferation were evaluated using cell scratch assays, cell migration assays, and cell proliferation assays. In vivo, MSC-EVs and UCB-EVs were injected around full-cut wounds to evaluate their efficacy of wound healing by measuring wound closure rates and scar width and performing histological analysis. ST was performed on skin tissue samples from mice in each group after wound healing to analyze the heterogeneity of major cell types compared with the control group and investigate potential mechanisms affecting wound healing and scar formation. In vitro experiments demonstrated that MSC-EVs and UCB-EVs promoted the proliferation and migration of HDF-a cells. Local injection of MSC-EVs and UCB-EVs into the periphery of a mouse skin wound accelerated re-epithelialization, promoted wound healing, and reduced scar width. ST analysis of skin tissue from each group after wound healing revealed that MSC-EVs and UCB-EVs reduced the relative expression of marker genes in myofibroblasts, regulated wound healing, and decreased scar formation by reducing the expression of the TGF-β signaling pathway and increasing the expression of the Wnt signaling pathway. The results suggest that MSC-EVs and UCB-EVs play a significant role in the activity of cord blood plasma-derived mesenchymal stem cells and cord blood plasma. They can be considered promising new agents for promoting skin wound healing.

Developmental changes of skin quality from breast, back, and thigh of Pekin ducks from 1 to 6 weeks of age

Good skin quality not only improved carcass quality but also increased consumer demand for fresh poultry meat. This study aimed to investigate the developmental changes in skin growth and quality of Pekin ducks during 1-6 weeks of age. The skin samples were collected from the breast, back, and thigh tissues of six male ducks at the end of each week. The skin strength, skin thickness, and collagen content as well as the related gene expressions were determined for the evaluation of skin quality. The results showed that the body weight, absolute skin weight, areas, and density, epidermal and dermal thickness (breast and thigh), shearing force, piercing force (back and thigh), and collagen content in Pekin ducks increased linearly and quadratically with age, reaching a plateau at 5-6 weeks of age (P < 0.05). The mRNA expressions of IGF-1 and FGFR1 related to cell proliferation were highest in breast, back, and thigh of ducks at 3 weeks of age, while the mRNA expression of FGF14 and EGF associated with collagen synthesis reached maximum values at 5 weeks of age. Additionally, the mRNA expressions of IGF1R and FGFR2 were upregulated in breast and thigh skins of ducks at 1 week old and in back skin of ducks at 3 weeks old compared with birds at other weeks old (P < 0.05). In conclusion, the developmental pattern of skin growth and structure of Pekin ducks in a linear manner with increased age. The skin quality was increased in a quadratic manner, which was associated with the changes in mRNA expression of target genes related to cell proliferation and collagen synthesis.

The role of multiomics in revealing the mechanism of skin repair and regeneration

Skin repair and regeneration are crucial processes in restoring the integrity of the skin after injury, with significant implications for medical treatments and plastic surgery. Multiomics, an integrated approach combining genomics, transcriptomics, proteomics, and metabolomics, offers unprecedented insights into the complex molecular and cellular mechanisms involved in skin healing. This review explores the transformative role of multiomics in elucidating the mechanisms of skin repair and regeneration. While genomic studies identify the genetic basis of wound healing, transcriptomics and proteomics uncover the dynamic changes in gene and protein expression, and metabolomics provides a snapshot of metabolic alterations associated with wound healing. Integrative multiomics studies can also identify novel biomarkers and therapeutic targets for skin regeneration. Despite the technical and biological challenges, the future of multiomics in skin research holds great promise for advancing personalized medicine and improving wound healing strategies. Through interdisciplinary collaboration, multiomics has the potential to revolutionize our understanding of skin repair, paving the way for innovative treatments in plastic surgery and beyond.

Pain-Related Responses in Preterm Babies Using Automated and Laser Heel-Lancing Devices

Purpose: This study aimed to compare the pain-related behavioral and physiological responses and puncture-related characteristics between automated and laser lancets and examine the correlation between infants' pain-related responses and facial expressions during heel lancing in a neonatal intensive care unit. Methods: Pain-related responses were assessed using the Neonatal Infant Pain Scale, heart rate, and oxygen saturation through pulse oximetry. Facial expressions were also analyzed using a facial recognition application. Puncture-related characteristics were assessed through puncture marks, number of punctures, and hemostasis. Results: There was a significantly higher puncture mark frequency at 3 min in the automated lancet group than in the laser lancet group. There were no interaction effects of time and group on pain-related behavioral response, heart rate, or oxygen saturation. There were significant positive correlations between the pain-related behavioral response and anger, disgust, fear, and sadness. Conclusion: The laser lancet had relatively good outcomes regarding puncture-related characteristics, although there was no significant difference in pain-related responses. A laser lancet is a novel option for preterm babies at risk of scar-related inflammation and coagulopathies.

pH-responsive hydrogel with dual-crosslinked network of polyvinyl alcohol/boric acid for controlled release of salvianolic acid B: novel pro-regenerative mechanisms in scar inhibition and wound healing

This study investigates a novel pH-responsive hydrogel composed of polyvinyl alcohol (PVA) and boric acid (BA) designed for the controlled release of salvianolic acid B (SAB), addressing the critical challenge of scar formation and skin regeneration. The dual-crosslinked network architecture of the hydrogel exhibits remarkable pH sensitivity, enabling it to achieve a peak SAB release within 48 hours in the acidic microenvironment characteristic of early-stage wound healing. In vitro assessments demonstrated that the PVA-BA-SAB hydrogel significantly inhibits fibroblast activation and mitigates abnormal collagen deposition, effectively preventing excessive scar formation. Transcriptome sequencing reveals the potential role of PVA-BA-SAB hydrogel in balancing TGF-β and Wnt signaling pathways. Furthermore, in vivo studies revealed enhanced tissue regeneration, characterized by improved collagen organization and increased vascularization, as well as the promotion of mature hair follicle development. The hydrogel's biocompatibility, mechanical robustness and adhesive properties were also thoroughly evaluated, confirming its suitability for clinical applications. These findings suggest that the PVA-BA-SAB hydrogel fully exerts the excellent characteristics of biomaterials and maximizes the pharmacological effect of SAB. Our innovative drug delivery system not only facilitates enhanced wound healing but also offers a strategic approach to minimize scarring. This research provides valuable insights into innovative therapeutic strategies for effective wound management and tissue repair.

Single cell transcriptomics reveals the cellular heterogeneity of keloids and the mechanism of their aggressiveness

Keloid is a dermatofibrotic disease known for its aggressive nature and characterized by pathological scarring, which often leads to disfigurement and frequent recurrences. Effective therapies for keloids are still limited, presumably due to the inadequate comprehension of their aggressive mechanisms. In our study, we examined the unique scenario where both keloid and non-aggressive pathological scar originate from the same patient, providing a rare opportunity to explore the aggressive mechanisms of keloids through single-cell RNA sequencing. We found that the dominant fibroblast subgroup in keloids is mechanoresponsive group, which showed enhanced mechanotransduction and migration. This mechanoresponsive fibroblast subgroup is likely to be the key cell population and confer aggressive growth of keloids. The results also indicate that the endothelial cells and keratinocytes in keloid involve in endothelial-mesenchymal and epithelial-mesenchymal transitions. This study demonstrated the mechanoresponsive fibroblasts and multiple cellular mesenchymal processes could pave the way for further investigations into the keloid aggressiveness.

Botulinum toxin type A inhibits the formation of hypertrophic scar through the JAK2/STAT3 pathway

Hypertrophic scar (HS) is a fibrous proliferative disorder that occurs in the dermis after skin injury. Studies have confirmed that Botulinum toxin type A (BTA) is effective in scar prevention and treatment. However, the specific mechanism remains uncertain. Hypertrophic scar fibroblasts (HSFs) and normal skin fibroblasts (NSFs) from the skin tissues of HS patients were isolated and cultured. Western blot analysis was conducted to measure the expression of JAK2/STAT3 pathway-related proteins. HSFs were treated with the JAK2 inhibitor (AG490) or agonist (C-A1). The CCK-8 assay, EdU staining, scratch-wound assay and transwell assay were used to examine the biological properties of HSFs. Western blot, immunofluorescence, and Sirius red staining were used to assess the fibrosis of HSFs. Additionally, a mouse full-thickness wound model was constructed to investigate the role of BTA in wound healing. The results showed that the JAK2 and STAT3 phosphorylation levels were markedly increased in HS tissues and HSFs. AG490 treatment reduced cell viability, proliferation and migration capacity, and inhibited the fibrosis of HSFs, whereas C-A1 treatment had the opposite effect. BTA treatment inhibited the JAK2/STAT3 pathway. BTA reduced cell viability, proliferation and migration ability, and inhibited the fibrosis of HSFs, while C-A1 intervention weakened the impact of BTA. Meanwhile, BTA promoted wound healing and reduced collagen deposition in vivo. In conclusion, BTA inhibited the JAK2/STAT3 pathway, which in turn hindered the proliferation, migration and fibrosis of HSFs, and promoted wound healing in mice.

Chitosan-Based Hydrogels as Antibacterial/Antioxidant/Anti-Inflammation Multifunctional Dressings for Chronic Wound Healing

Due to repeated microbial infection, persistent inflammation, excessive oxidative stress, and cell dysfunction, chronic wounds are difficult to heal, posing a serious threat to public health. Therefore, developing multifunctional wound dressings that can regulate the complex microenvironment of chronic wounds and enhance cellular function holds great significance. Recently, chitosan has emerged as a promising biopolymer for wound healing due to its excellent biocompatibility, biodegradability, and versatile bioactivity. The aim of this review is to provide a comprehensive understanding of the mechanisms of delayed chronic wound healing and discuss the healing-promoting properties of chitosan and its derivatives, such as good biocompatibility, antibacterial activity, hemostatic capacity, and the ability to promote tissue regeneration. On this basis, the potential applications of chitosan-based hydrogels are summarized in chronic wound healing, including providing a suitable microenvironment, eliminating bacterial infections, promoting hemostasis, inhibiting chronic inflammation, alleviating oxidative stress, and promoting tissue regeneration. In addition, the concerns and perspectives for the clinical application of chitosan-based hydrogels are also discussed.

The interplay of skin architecture and cellular dynamics in wound healing: Insights and innovations in care strategies

Wound healing involves complex interactions among skin layers: the epidermis, which epithelializes to cover wounds; the dermis, which supports granulation tissue and collagen production; and the hypodermis, which protects overall skin structure. Key factors include neutrophils, activated by platelet degranulation and cytokines, and fibroblasts, which aid in collagen production during proliferation. The healing process encompasses inflammation, proliferation, and remodeling, with angiogenesis, fibroplasia, and re-epithelialization crucial for wound closure. Angiogenesis is characterized by the creation of collateral veins, the proliferation of endothelial cells, and the recruitment of perivascular cells. Collagen is produced by fibroblasts in granulation tissue, aiding in the contraction of wounds. The immunological response is impacted by T cells and cytokines. External topical application of various formulations and dressings expedites healing and controls microbial contamination. Polymeric materials, both natural and synthetic, and advanced dressings enhance healing by providing biodegradability, biocompatibility, and infection control, thus addressing tissue regeneration challenges. Numerous dressings promote healing, including films, hydrocolloids, hydrogels, foams, alginates, and tissue-engineered substitutes. Wound dressings are treated with growth factors, particularly PDGF, and antibacterial drugs to prevent infection. The challenges of tissue regeneration and infection control are evolving along with the field of wound care.

Research Progress of Fibroblasts in Human Diseases

Fibroblasts, which originate from embryonic mesenchymal cells, are the predominant cell type seen in loose connective tissue. As the main components of the internal environment that cells depend on for survival, fibroblasts play an essential role in tissue development, wound healing, and the maintenance of tissue homeostasis. Furthermore, fibroblasts are also involved in several pathological processes, such as fibrosis, cancers, and some inflammatory diseases. In this review, we analyze the latest research progress on fibroblasts, summarize the biological characteristics and physiological functions of fibroblasts, and delve into the role of fibroblasts in disease pathogenesis and explore treatment approaches for fibroblast-related diseases.

Spatiotemporal characterization of extracellular matrix maturation in human artificial stromal-epithelial tissue substitutes

BACKGROUND

Tissue engineering techniques offer new strategies to understand complex processes in a controlled and reproducible system. In this study, we generated bilayered human tissue substitutes consisting of a cellular connective tissue with a suprajacent epithelium (full-thickness stromal-epithelial substitutes or SESS) and human tissue substitutes with an epithelial layer generated on top of an acellular biomaterial (epithelial substitutes or ESS). Both types of artificial tissues were studied at sequential time periods to analyze the maturation process of the extracellular matrix.

RESULTS

Regarding epithelial layer, ESS cells showed active proliferation, positive expression of cytokeratin 5, and low expression of differentiation markers, whereas SESS epithelium showed higher differentiation levels, with a progressive positive expression of cytokeratin 10 and claudin. Stromal cells in SESS tended to accumulate and actively synthetize extracellular matrix components such as collagens and proteoglycans in the stromal area in direct contact with the epithelium (zone 1), whereas these components were very scarce in ESS. Regarding the basement membrane, ESS showed a partially differentiated structure containing fibronectin-1 and perlecan. However, SESS showed higher basement membrane differentiation, with positive expression of fibronectin 1, perlecan, nidogen 1, chondroitin-6-sulfate proteoglycans, agrin, and collagens types IV and VII, although this structure was negative for lumican. Finally, both ESS and SESS proved to be useful tools for studying metabolic pathway regulation, revealing differential activation and upregulation of the transforming growth factor-β pathway in ESS and SESS.

CONCLUSIONS

These results confirm the relevance of epithelial-stromal interaction for extracellular matrix development and differentiation, especially regarding basement membrane components, and suggest the usefulness of bilayered artificial tissue substitutes to reproduce ex vivo the extracellular matrix maturation and development process of human tissues.

Hormonal interventions in skin wounds - a mini review

The ability to heal from wounds is perhaps the most important biological function that ensures our survival and perpetuation. Cutaneous wound healing typically consists of four characteristic stages, namely hemostasis, inflammation, proliferation, and remodeling, which are carefully carried out by coordinated actions of various cells, cytokines, and hormones. Incoordination of these steps may impede complete and efficient reconstruction and functional recovery of wounds or even lead to worsened outcomes. Hormones, as powerful modulators of organ functions, participate in multiple steps of the wound healing process and play a pivotal role by choreographing the complex interplay of cellular and molecular events. Leveraging the regulatory effects of hormones to enhance the healing process, hormonal therapy has emerged as a promising approach in the clinical treatment of wounds. Current research has focused on determination of the optimal dosages, delivery methods, and combinations of hormonal therapies to maximize their therapeutic benefits while minimizing potential side effects. This review highlights the molecular mechanisms, clinical benefits and side effects of the most commonly used hormones in clinical treatment of wounds.

Recent advances in the 3D skin bioprinting for regenerative medicine: Cells, biomaterials, and methods

The skin is a tissue constantly exposed to the risk of damage, such as cuts, burns, and genetic disorders. The standard treatment is autograft, but it can cause pain to the patient being extremely complex in patients suffering from burns on large body surfaces. Considering that there is a need to develop technologies for the repair of skin tissue like 3D bioprinting. Skin is a tissue that is approximately 1/16 of the total body weight and has three main layers: epidermis, dermis, and hypodermis. Therefore, there are several studies using cells, biomaterials, and bioprinting for skin regeneration. Here, we provide an overview of the structure and function of the epidermis, dermis, and hypodermis, and showed in the recent research in skin regeneration, the main cells used, biomaterials studied that provide initial support for these cells, allowing the growth and formation of the neotissue and general characteristics, advantages and disadvantages of each methodology and the landmarks in recent research in the 3D skin bioprinting.

Transdermal Drug Delivery Systems: Different Generations and Dermatokinetic Assessment of Drug Concentration in Skin

Transdermal drug delivery systems (TDDS) are a highly appealing and innovative method of administering drugs through the skin, as it enables the drugs to achieve systemic effects. A TDDS offers patient convenience, avoids first-pass hepatic metabolism, enables local targeting, and reduces the toxic effect of drug. This review details several generations of TDDS and the advancements made in their development to address the constraints associated with skin delivery systems. Transdermal delivery methods of the first generation have been consistently growing in their clinical application for administering small, lipophilic, low-dose drugs. Second-generation TDDS, utilizing chemical enhancers and iontophoresis, have led to the development of clinical products. Third-generation delivery systems employ microneedles, thermal ablation, and electroporation to specifically target the stratum corneum, which is the skin's barrier layer. Dermatokinetics is the study of the movement of drugs and formulations applied to the skin over a period of time. It provides important information regarding the rate and extent to which drugs penetrate skin layers. Several dermatokinetic techniques, including tape stripping, microdialysis, and laser scanning microscopy, have been used to study the intricate barrier properties and clearance mechanisms of the skin. This understanding is essential for developing and improving effective TDDS.

Decoding the impact of ageing and environment stressors on skin cell communication

The integumentary system serves as a crucial protective barrier and is subject to complex signaling pathways that regulate its physiological functions. As the body's first line of defense, the skin is continuously exposed to environmental stressors, necessitating a robust network of signaling molecules to maintain homeostasis. Considering the main cellular components to be keratinocytes, melanocytes, fibroblasts, and fibrous components, collagen of various types, this review explores the intricate signaling mechanisms that govern skin integrity, focusing on key pathways involved in impacts of ageing and environment factors on skin health. The role of growth factors, cytokines, hormones and other molecular mediators in these processes is examined. Specially for women, decrease of estrogen is determinant to alter signaling and to compromise skin structure, especially the dermis. Environmental factors, such as ultraviolet rays and pollution alongside the impact of ageing on signaling pathways, especially TGF-β and proteases (metalloproteinases and cathepsins). Furthermore, with advancing age, the skin's capacity to shelter microbiome challenges diminishes, leading to alterations in signal transduction and subsequent functional decline. Understanding these age-related changes is essential for developing targeted therapies aimed at enhancing skin health and resilience, but also offers a promising avenue for the treatment of skin disorders and the promotion of healthy ageing.

Assessing the Influence of Hyaluronan Dressing on Wound Healing on Split-Thickness Skin Graft Donor Sites Using a Three-Dimensional Scanner

Objectives: The topical application of hyaluronic acid after injury may accelerate the wound healing process. We aimed to retrospectively investigate whether the topical application of hyaluronic acid on standardized wounds after split-thickness skin graft removal on the thigh would accelerate wound healing and improve scarring outcomes. Additionally, we aimed to evaluate the usefulness of three-dimensional (3D) scanning to assess scars. Methods: The wound healing process of a hyaluronan group (n = 20) and a control (n = 21) were analyzed and evaluated using 3D scans at 7 and 14 days and 1, 3, and 6 months post-operatively. Scar evaluations by the patients were conducted 6 months post-operatively using the patient and observer scar assessment scale and the Manchester scar scale. Experts evaluated the scars after 6 months using a modified version of both scales. Results: On days 7 and 14, significantly larger areas of the wound surface were closed in the hyaluronan group compared to the control group (p < 0.05). After 1 month, significantly more crusted areas remained in the control group than in the hyaluronan group (p < 0.05). At the 6-month self-assessments, the hyaluronan group evaluated their scars as being significantly better compared to the control group. Conclusions: The topical application of hyaluronic acid in combination with polyurethane foam as a wound dressing after split skin removal accelerated the wound healing rate and positively influenced scar appearance after 6 months. Three-dimensional scanning is useful for evaluating and documenting the wound healing process.

Skin senescence-from basic research to clinical practice

The most recognizable implications of tissue aging manifest themselves on the skin. Skin laxity, roughness, pigmentation disorders, age spots, wrinkles, telangiectasia or hair graying are symptoms of physiological aging. Development of the senescent phenotype depends on the interaction between aging cells and remodeling of the skin's extracellular matrix (ECM) that contains collagen and elastic fiber. Aging changes occur due to the combination of both endogenous (gene mutation, cellular metabolism or hormonal agents) and exogenous factors (ultraviolet light, environmental pollutants, and unsuitable diet). However, overproduction of mitochondrial reactive oxygen species (ROS) is a key factor driving cellular senescence. Aging theories have disclosed a range of diverse molecular mechanisms that are associated with cellular senescence of the body. Theories best supported by evidence include protein glycation, oxidative stress, telomere shortening, cell cycle arrest, and a limited number of cell divisions. Accumulation of the ECM damage is suggested to be a key factor in skin aging. Every cell indicates a functional and morphological change that may be used as a biomarker of senescence. Senescence-associated β-galactosidase (SA-β-gal), cell cycle inhibitors (p16INK4a, p21CIP1, p27, p53), DNA segments with chromatin alterations reinforcing senescence (DNA-SCARS), senescence-associated heterochromatin foci (SAHF), shortening of telomeres or downregulation of lamina B1 constitute just an example of aging biomarkers known so far. Aging may also be assessed non-invasively through measuring the skin fluorescence of advanced glycation end-products (AGEs). This review summarizes the recent knowledge on the pathogenesis and clinical conditions of skin aging as well as biomarkers of skin senescence.

Enhancing Cellular Homeostasis: Targeted Botanical Compounds Boost Cellular Health Functions in Normal and Premature Aging Fibroblasts

The human skin, the body's largest organ, undergoes continuous renewal but is significantly impacted by aging, which impairs its function and leads to visible changes. This study aimed to identify botanical compounds that mimic the anti-aging effects of baricitinib, a known JAK1/2 inhibitor. Through in silico screening of a botanical compound library, 14 potential candidates were identified, and 7 were further analyzed for their effects on cellular aging. The compounds were tested on both normal aged fibroblasts and premature aging fibroblasts derived from patients with Hutchinson-Gilford Progeria Syndrome (HGPS). Results showed that these botanical compounds effectively inhibited the JAK/STAT pathway, reduced the levels of phosphorylated STAT1 and STAT3, and ameliorated phenotypic changes associated with cellular aging. Treatments improved cell proliferation, reduced senescence markers, and enhanced autophagy without inducing cytotoxicity. Compounds, such as Resveratrol, Bisdemethoxycurcumin, Pinosylvin, Methyl P-Hydroxycinnamate, cis-Pterostilbene, and (+)-Gallocatechin, demonstrated significant improvements in both control and HGPS fibroblasts. These findings suggest that these botanical compounds have the potential to mitigate age-related cellular alterations, offering promising strategies for anti-aging therapies, particularly for skin health. Further in vivo studies are warranted to validate these results and explore their therapeutic applications.

A Degradable Bioelectronic Scaffold for Localized Cell Transfection toward Enhancing Wound Healing in a 3D Space

Large skin wounds, with extensive surface area and deep vertical full-thickness involvement, can pose significant challenges in clinical settings. Traditional routes for repairing skin wounds encompass three hallmarks: 1) scab formation for hemostasis; 2) proliferation and migration of epidermal cells for wound closure; 3) proliferation, migration, and functionalization of fibroblasts and endothelial cells for dermal remodeling. However, this route face remarkable challenges to healing large wounds, usually leading to disordered structures and loss of functions in the regenerated skin, due to limited control on the transition among the three stages. In this work, an implantable bioelectronics is developed that enables the synchronization of the three stages, offering accelerated and high-quality healing of large skin wounds. The system efficiently electro-transfect local cells near the wounds, forcing cellular proliferation, while providing a 3D porous environments for synchronized migration of epidermal and dermal cells. In vivo experiments demonstrated that the system achieved synchronous progression of multiple layers within the wounds, leading to the reconstruction of a complete skin structure similar to healthy skin, which presents a new avenue for the clinical translation of large wound healing.

CD9 promotes TβR2-TβR1 association driving the transition of human dermal fibroblasts to myofibroblast under hypoxia

BACKGROUND

During wound healing, fibroblast to myofibroblast transition is required for wound contraction and remodeling. While hypoxia is an important biophysical factor in wound microenvironment, the exact regulatory mechanism underlying hypoxia and fibroblast-to-myofibroblast transition remains unclear. We previously found that tetraspanin CD9 plays an important role in oxygen sensing and wound healing. Herein, we investigated the effects of physiological hypoxia on fibroblast-to-myofibroblast transition and the biological function and mechanism of CD9 in it.

METHODS

Human skin fibroblasts (HSF) and mouse dermis wounds model were established under physiological hypoxia (2% O2). The cell viability and contractility of HSF under hypoxia were evaluated by CCK8 and collagen gel retraction, respectively. The expression and distribution of fibroblast-to-myofibroblast transition markers and CD9 in HSF were detected by Western blotting and immunofluorescence. CD9 slicing and overexpressing HSFs were constructed to determine the role of CD9 by small interfering RNA and recombinant adenovirus vector. The association of TβR2 and TβR1 was measured by immunoprecipitation to explore the regulatory mechanism. Additionally, further validation was conducted on mouse dermis wounds model through histological analysis.

RESULTS

Enhanced fibroblast-to-myofibroblast transition and upregulated CD9 expression was observed under hypoxia in vitro and in vivo. Besides, reversal of fibroblast-to-myofibroblast transition under hypoxia was observed when silencing CD9, suggesting that CD9 played a key role in this hypoxia-induced transition. Moreover, hypoxia increased fibroblast-to-myofibroblast transition by activating TGF-β1/Smad2/3 signaling, especially increased interaction of TβR2 and TβR1. Ultimately, CD9 was determined to directly affect TβR1-TβR2 association in hypoxic fibroblast.

CONCLUSION

Collectively, these findings suggest that CD9 promotes TβR2-TβR1 association, thus driving the transition of human dermal fibroblasts to myofibroblast under hypoxia.

Ideal Living Skin Equivalents, From Old Technologies and Models to Advanced Ones: The Prospects for an Integrated Approach

The development of technologies for the generation and transplantation of living skin equivalents (LSEs) is a significant area of translational medicine. Such functional equivalents can be used to model and study the morphogenesis of the skin and its derivatives, to test drugs, and to improve the healing of chronic wounds, burns, and other skin injuries. The evolution of LSEs over the past 50 years has demonstrated the leap in technology and quality and the shift from classical full-thickness LSEs to principled new models, including modification of classical models and skin organoids with skin derived from human-induced pluripotent stem cells (iPSCs) (hiPSCs). Modern methods and approaches make it possible to create LSEs that successfully mimic native skin, including derivatives such as hair follicles (HFs), sebaceous and sweat glands, blood vessels, melanocytes, and nerve cells. New technologies such as 3D and 4D bioprinting, microfluidic systems, and genetic modification enable achievement of new goals, cost reductions, and the scaled-up production of LSEs.

Advances in Skin-on-a-Chip Technologies for Dermatological Disease Modeling

Skin-on-a-chip (SoC) technologies are emerging as a paradigm shift in dermatology research by replicating human physiology in a dynamic manner not achievable by current animal models. Although animal models have contributed to successful clinical trials, their ability to predict human outcomes remains questionable, owing to inherent differences in skin anatomy and immune response. Covering areas including infectious diseases, autoimmune skin conditions, wound healing, drug toxicity, aging, and antiaging, SoC aims to circumvent the inherent disparities created by traditional models. In this paper, we review current SoC technologies, highlighting their potential as an alternative to animal models for a deeper understanding of complex skin conditions.

Silver and Carbon Nanomaterials/Nanocomplexes as Safe and Effective ACE2-S Binding Blockers on Human Skin Cell Lines

(1) Background: Angiotensin-converting enzyme 2 (ACE2) is a crucial functional receptor of the SARS-CoV-2 virus. Although the scale of infections is no longer at pandemic levels, there are still fatal cases. The potential of the virus to infect the skin raises questions about new preventive measures. In the context of anti-SARS-CoV-2 applications, the interactions of antimicrobial nanomaterials (silver, Ag; diamond, D; graphene oxide, GO and their complexes) were examined to assess their ability to affect whether ACE2 binds with the virus. (2) Methods: ACE2 inhibition competitive tests and in vitro treatments of primary human adult epidermal keratinocytes (HEKa) and primary human adult dermal fibroblasts (HDFa) were performed to assess the blocking capacity of nanomaterials/nanocomplexes and their toxicity to cells. (3) Results: The nanocomplexes exerted a synergistic effect compared to individual nanomaterials. HEKa cells were more sensitive than HDFa cells to Ag treatments and high concentrations of GO. Cytotoxic effects were not observed with D. In the complexes, both carbonic nanomaterials had a soothing effect against Ag. (4) Conclusions: The Ag5D10 and Ag5GO10 nanocomplexes seem to be most effective and safe for skin applications to combat SARS-CoV-2 infection by blocking ACE2-S binding. These nanocomplexes should be evaluated through prolonged in vivo exposure. The expected low specificity enables wider applications.

A New Nanoplatform Under NIR Released ROS Enhanced Photodynamic Therapy and Low Temperature Photothermal Therapy for Antibacterial and Wound Repair

Purpose

Skin injury, often caused by physical or medical mishaps, presents a significant challenge as wound healing is critical to restore skin integrity and tissue function. However, external factors such as infection and inflammation can hinder wound healing, highlighting the importance of developing biomaterials with antibiotic and wound healing properties to treat infections and inflammation. In this study, a novel photothermal nanomaterial (MMPI) was synthesized for infected wound healing by loading indocyanine green (ICG) on magnesium-incorporated mesoporous bioactive glass (Mg-MBG) and coating its surface with polydopamine (PDA).

Results

In this study, Mg-MBG and MMPI was synthesized via the sol-gel method and characterized it using various techniques such as scanning electron microscopy (SEM), the energy dispersive X-ray spectrometry (EDS) system and X-ray diffraction (XRD). The cytocompatibility of MMPI was evaluated by confocal laser scanning microscopy (CLSM), CCK8 assay, live/dead staining and F-actin staining of the cytoskeleton. The antibacterial efficiency was assessed using bacterial dead-acting staining, spread plate method (SPM) and TEM. The impact of MMPI on macrophage polarization was initially evaluated through flow cytometry, qPCR and ELISA. Additionally, an in vivo experiment was performed on a mouse model with skin excision infected. Histological analysis and RNA-seq analysis were utilized to analyze the in vivo wound healing and immunomodulation effect.

Conclusion

Collectively, the new photothermal and photodynamic nanomaterial (MMPI) can achieve low-temperature antibacterial activity while accelerating wound healing, holds broad application prospects.

Exosomes derived from mouse vibrissa dermal papilla cells promote hair follicle regeneration during wound healing by activating Wnt/β-catenin signaling pathway

Hair follicle (HF) regeneration during wound healing continues to present a significant clinical challenge. Dermal papilla cell-derived exosomes (DPC-Exos) hold immense potential for inducing HF neogenesis. However, the accurate role and underlying mechanisms of DPC-Exos in HF regeneration in wound healing remain to be fully explained. This study, represents the first analysis into the effects of DPC-Exos on fibroblasts during wound healing. Our findings demonstrated that DPC-Exos could stimulate the proliferation and migration of fibroblasts, more importantly, enhance the hair-inducing capacity of fibroblasts. Fibroblasts treated with DPC-Exos were capable of inducing HF neogenesis in nude mice when combined with neonatal mice epidermal cells. In addition, DPC-Exos accelerated wound re-epithelialization and promoted HF regeneration during the healing process. Treatment with DPC-Exos led to increased expression levels of the Wnt pathway transcription factors β-catenin and Lef1 in both fibroblasts and the dermis of skin wounds. Specifically, the application of a Wnt pathway inhibitor reduced the effects of DPC-Exos on fibroblasts and wound healing. Accordingly, these results offer evidence that DPC-Exos promote HF regeneration during wound healing by enhancing the hair-inducing capacity of fibroblasts and activating the Wnt/β-catenin signaling pathway. This suggests that DPC-Exos may represent a promising therapeutic strategy for achieving regenerative wound healing.

Liposomes Loaded with 5-Fluorouracil Can Improve the Efficacy in Pathological Scars

Introduction

Pathological scars, such as hypertrophic scars and keloids, are characterized by the proliferation of fibroblasts and the deposition of collagen that often cause pruritus, pain, and disfigurement. Due to their high incidence and deformity, pathological scars have resulted in severe physical and psychological trauma for patients. Intralesional injection of 5-fluorouracil (5-Fu) is a recommended option for treating pathological scars. However, the efficacy of 5-Fu injection was limited and unstable due to limited drug penetration and short retention time.

Methods

Liposomes are promising carriers that have advantages, such as high biocompatibility, controlled release property, and enhanced clinical efficacy. Here, we constructed a transdermal 5-Fu-loaded liposome (5-Fu-Lip) to provide a more effective and safer modality to scar treatment.

Results

Compared to 5-Fu, 5-Fu-Lip showed superior ability in inhibiting primary keloid fibroblasts proliferation, migration, and collagen deposition, and also significantly inhibited human umbilical vein endothelial cells (HUVECs) proliferation and microvessel construction. In vivo experiments demonstrated that 5-Fu-Lip can significantly reduce the severity of hypertrophic scars in a rabbit ear wounding model.

Discussion

5-Fu-Lip provides a promising strategy to improve drug efficacy, which has great potential in the treatment of pathological scars.

Fibroblast alignment and matrix remodeling induced by a stiffness gradient in a skin-derived extracellular matrix hydrogel

Large skin injuries heal as scars. Stiffness gradually increases from normal skin to scar tissue (20x higher), due to excessive deposition and crosslinking of extracellular matrix (ECM) mostly produced by (myo)fibroblasts. Using a custom mold, skin-derived ECM hydrogels (dECM) were UV crosslinked after diffusion of ruthenium (Ru) to produce a Ru-dECM gradient hydrogel. The Ru diffusion gradient equates to a stiffness gradient and models physiology of the scarred skin. Crosslinking in Ru-dECM hydrogels results in a 23-fold increase in stiffness from a stiffness similar to that of normal skin. Collagen fiber density increases in a stiffness-dependent fashion while stress relaxation also alters, with one additional Maxwell element necessary for characterizing Ru-dECM. Alignment of fibroblasts encapsulated in hydrogels suggests that the stiffness gradient directs fibroblasts to orientate at ∼45 ° in regions below 120 kPa. In areas above 120 kPa, fibroblasts decrease the stiffness prior to adjusting their orientation. Furthermore, fibroblasts remodel their surrounding ECM in a gradient-dependent fashion, with rearrangement of cell-surrounding ECM in high-stiffness areas, and formation of interlaced collagen bundles in low-stiffness areas. Overall, this study shows that fibroblasts remodel their local environment to generate an optimal ECM mechanical and topographical environment. STATEMENT OF SIGNIFICANCE: This study developed a versatile in vitro model with a gradient stiffness using skin-derived ECM hydrogel with unchanged biochemical environment. Using Ruthenium crosslinking, a 20-fold stiffness increase was achieved as observed in fibrotic skin. The interaction between fibroblasts and matrix depends on changes in the matrix stiffness. The stiffness gradient directed the alignment of fibroblasts with ∼45° in regions with≤ 120 kPa. The cells in regions with the higher stiffness decreased stiffness first and then oriented themselves. Furthermore, fibroblasts remodeled surrounding ECM and regulated its mechanics in a gradient-dependent fashion to reach an optimal condition. Our study highlights the dynamic interplay between cells and surrounding matrix, shedding light on potential mechanisms and strategies to target scar formation and remodeling.

Thrombospondin 2, matrix Gla protein and digital analysis identified distinct fibroblast populations in fibrostenosing Crohn's disease

Fibrosis is an important complication in inflammatory bowel diseases. Previous studies suggest an important role of matrix Gla protein (MGP) and thrombospondin 2 (THBS2) in fibrosis in various organs. Our aim was to analyse their expression together with regulatory miRNAs in submucosal and subserosal fibroblasts in ulcerative colitis (UC) and Crohn's disease (CD) using immunohistochemistry and qPCR. Digital pathology was used to compare collagen fibre characteristics of submucosal and subserosal fibrosis. Immunohistochemistry showed expression of MGP, but not THBS2 in submucosa in UC and CD. In the subserosa, there was strong staining for both proteins in CD but not in UC. qPCR showed significant upregulation of THBS2 and MGP genes in CD subserosa compared to the submucosa. Digital pathology analysis revealed higher proportion of larger and thicker fibres that were more tortuous and reticulated in subserosal fibrosis compared to submucosal fibrosis. These results suggest distinct fibroblast populations in fibrostenosing CD, and are further supported by image analysis showing significant differences in the morphology and architecture of collagen fibres in submucosal fibrosis in comparison to subserosal fibrosis. Our study is the first to describe differences in submucosal and subserosal fibroblast populations, contributing to understanding of the pathogenesis of fibrostenosis in CD.

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.

Role of Dermatix in the Management of Eyelid Hypertrophic Scars After Facial Trauma

Facial trauma can cause skin wounds with uneven and discoloured edges that require healing by secondary intention. These wounds often produce excess collagen fibres, leading to fibrosis and hypertrophic scars that can cause discomfort and negatively impact the patient's quality of life. A man suffered facial trauma due to a motor vehicle accident, resulting in a fracture of the left zygomatic-maxillary complex. He underwent surgery to fix the fracture and reconstruct his eyelid but developed a hypertrophic scar during recovery that caused eye dryness and discomfort. To treat the scar, Dermatix silicone gel (SG) (Viatris, Canonsburg, PA) was applied twice a day. After two months of treatment, the scar had improved significantly, and the patient's eyelid function had also improved. This case describes the use of Dermatix SG to treat a patient with a traumatic hypertrophic scar of the eyelid associated with eyelid malposition. Silicone gel is a non-invasive treatment for scars and has been shown to be effective in reducing scar elevation and erythema. However, there is a gap in the literature regarding the routine use of SG to preserve functionality and aesthetics in traumatic hypertrophic scars of complex anatomical structures. Further studies are needed to understand the principles of using SG for these types of scars to improve functional and aesthetic outcomes. Applying Dermatix SG twice a day for 60 days corrected a patient's functional and aesthetic issues. More studies should be conducted to investigate the product's effectiveness further.

Multifunctional Hydrogel Enhances Inflammatory Control, Antimicrobial Activity, and Oxygenation to Promote Healing in Infectious Wounds

Chronic infected wounds often fail to heal through normal repair mechanisms, and the persistent response of reactive oxygen species (ROS) and inflammation is a major contributing factor to the difficulty in their healing. In this context, we developed an ROS-responsive injectable hydrogel. This hydrogel is composed of ε-polylysine grafted (EPL) with caffeic acid (CA) and hyaluronic acid (HA) grafted with phenylboronic acid (PBA). Before the gelation process, a mixture CaO2@Cur-PDA (CCP) consisting of calcium peroxide (CaO2) coated with polydopamine (PDA) and curcumin (Cur) is embedded into the hydrogel. Under the conditions of chronic refractory wound environments, the hydrogel gradually dissociates. HA mimics the function of the extracellular matrix, while the released caffeic acid-grafted ε-polylysine (CE) effectively eliminates bacteria in the wound vicinity. Additionally, released CA also clears ROS and influences macrophage polarization. Subsequently, CCP further decomposes, releasing Cur, which promotes angiogenesis. This multifunctional hydrogel accelerates the repair of diabetic skin wounds infected with Staphylococcus aureus in vivo and holds promise as a candidate dressing for the healing of chronic refractory wounds.

An insight into the microbiome associated with the damage of raw animal hide and skin-primarily protein, during leather making

Leather processing is vital for the economy of many developing countries, nevertheless, this industry is faced with issues of leather down-grading owing to its low quality leading to economic loss. In addition to defects due to scratch, wound, scar, etc., the down-grading of hide and skin due to microbial putrefaction is also of concern. The major components of raw hide and skin being proteins, fats and minerals, they act as excellent medium for the growth and proliferation of bacteria, leading to putrefaction. Sometimes the damage is more apparent at pickled and wet-blue stage of leather making. The tanned leather is prone to decay by fungi during processing and even after storage as well. Hence, it is quite essential to understand the microbiome of raw hide and skin to gain a deeper insight into the process of putrefaction. This review aims to discuss about the microbes commonly associated with putrefaction of raw animal hide and skin which are capable to cause putrefaction. A few occasions, where infection was caused due to microbes during the life span of animal but the defect was visible only after leather was made out of the hide and skin of infected animal, have also been discussed.

[Influences and mechanism of extracellular vesicles from dermal papilla cells of mice on human hypertrophic scar fibroblasts]

Objective: To investigate the influences and mechanism of extracellular vesicles from dermal papilla cells (DPC-EVs) of mice on human hypertrophic scar fibroblasts (HSFs). Methods: The study was an experimental research. The primary dermal papilla cells (DPCs) of whiskers were extracted from 10 6-week-old male C57BL/6J mice and identified successfully. The DPC-EVs were extracted from the 3rd to 5th passage DPCs by ultracentrifugation, and the morphology was observed through transmission electron microscope and the particle diameter was detected by nanoparticle tracking analyzer (n=3) at 24 h after culture. The 3rd passage of HSFs were divided into DPC-EV group and phosphate buffer solution (PBS) group, which were cultured with DPC-EVs and PBS, respectively. The cell scratch test was performed and cell migration rate at 24 h after scratching was calculated (n=5). The cell proliferation levels at 0 (after 12 h of starvation treatment and before adding DPC-EVs or PBS), 24, 48, 72, and 96 h after culture were detected by using cell counting kit 8 (n=4). The protein expressions of α-smooth muscle actin (α-SMA) and collagen typeⅠ (ColⅠ) in cells at 24 h after culture were detected by immunofluorescence method and Western blotting, and the protein expression of Krüppel-like factor 4 (KLF4) in cells at 24 h after culture was detected by Western blotting. After the 3rd passage of HSFs were cultured with DPC-EVs for 24 h, the cells were divided into blank control group, KLF4 knockdown group, and KLF4 overexpression group according to the random number table. The cells in blank control group were only routinely cultured for 48 h. The cells in KLF4 knockdown group and KLF4 overexpression group were incubated with KLF4 knockdown virus for 24 h, then the cells in KLF4 knockdown group were routinely cultured for 24 h while the cells in KLF4 overexpression group were incubated with KLF4 overexpression virus for 24 h. The protein expressions of KLF4, α-SMA, and ColⅠ in cells were detected by Western blotting at 48 h after culture. Results: At 24 h after culture, the extracted DPC-EVs showed vesicular structure with an average particle diameter of 108.8 nm. At 24 h after scratching, the migration rate of HSFs in PBS group was (54±10)%, which was significantly higher than (29±8)% in DPC-EV group (t=4.37, P<0.05). At 48, 72, and 96 h after culture, the proliferation levels of HSFs in DPC-EV group were significantly lower than those in PBS group (with t values of 4.06, 5.76, and 6.41, respectively, P<0.05). At 24 h after culture, the protein expressions of α-SMA and ColⅠ of HSFs in DPC-EV group were significantly lower than those in PBS group, while the protein expression of KLF4 was significantly higher than that in PBS group. At 48 h after culture, compared with those in blank control group, the protein expression of KLF4 of HSFs in KLF4 knockdown group was down-regulated, while the protein expressions of α-SMA and ColⅠ were both up-regulated; compared with those in KLF4 knockdown group, the protein expression of KLF4 of HSFs in KLF4 overexpression group was up-regulated, while the protein expressions of ColⅠ and α-SMA were down-regulated. Conclusions: The DPC-EVs of mice can inhibit the proliferation and migration of human HSFs and significantly inhibit the expressions of fibrosis markers α-SMA and ColⅠ in human HSFs by activating KLF4.

Transcriptome network analysis of inflammation and fibrosis in keloids

BACKGROUND

Keloid (KL) is a common benign skin tumor. KL is typically characterized by significant fibrosis and an intensive inflammatory response. Therefore, a comprehensive understanding of the interactions between cellular inflammation and fibrotic cells is essential to elucidate the mechanisms driving the progression of KL and to develop therapeutics.

OBJECTIVE

Investigate the transcriptome landscape of inflammation and fibrosis in keloid scars.

METHODS

In this paper, we performed transcriptome sequencing and microRNA (miRNA) sequencing on unselected live cells from six human keloid tissues and normal skin tissues to elucidate a comprehensive transcriptome landscape. In addition, we used single-cell RNA sequencing (scRNA-seq) analysis to analyze intercellular communication networks and enrich fibroblast populations in two additional keloid and normal skin samples to study fibroblast diversity.

RESULTS

By RNA sequencing and a miRNA-mRNA-PPI network analysis, we identified miR-615-5p and miR-122b-3p as possible miRNAs associated with keloids, as they differed most significantly in keloids. Similarly, COL3A1, COL1A2, THBS2, TNC, IGTA, THBS4, TGFB3 as genes with significant differences in keloid may be associated with keloid development. Using single-cell RNA sequencing data from 24,086 cells collected from normal or keloid, we report reconstructed intercellular signaling network analysis and aggregation to modules associated with specific cell subpopulations at the cellular level for keloid alterations.

CONCLUSIONS

Our multitranscriptomic dataset delineates inflammatory and fibro heterogeneity of human keloids, underlining the importance of intercellular crosstalk between inflammatory cells and fibro cells and revealing potential therapeutic targets.

Novel Therapeutic Hybrid Systems Using Hydrogels and Nanotechnology: A Focus on Nanoemulgels for the Treatment of Skin Diseases

Topical and transdermal drug delivery are advantageous administration routes, especially when treating diseases and conditions with a skin etiology. Nevertheless, conventional dosage forms often lead to low therapeutic efficacy, safety issues, and patient noncompliance. To tackle these issues, novel topical and transdermal platforms involving nanotechnology have been developed. This review focuses on the latest advances regarding the development of nanoemulgels for skin application, encapsulating a wide variety of molecules, including already marketed drugs (miconazole, ketoconazole, fusidic acid, imiquimod, meloxicam), repurposed marketed drugs (atorvastatin, omeprazole, leflunomide), natural-derived compounds (eucalyptol, naringenin, thymoquinone, curcumin, chrysin, brucine, capsaicin), and other synthetic molecules (ebselen, tocotrienols, retinyl palmitate), for wound healing, skin and skin appendage infections, skin inflammatory diseases, skin cancer, neuropathy, or anti-aging purposes. Developed formulations revealed adequate droplet size, PDI, viscosity, spreadability, pH, stability, drug release, and drug permeation and/or retention capacity, having more advantageous characteristics than current marketed formulations. In vitro and/or in vivo studies established the safety and efficacy of the developed formulations, confirming their therapeutic potential, and making them promising platforms for the replacement of current therapies, or as possible adjuvant treatments, which might someday effectively reach the market to help fight highly incident skin or systemic diseases and conditions.

The efficacy and safety of low- versus high-fluence fractional picosecond Nd:YAG 1064-nm laser in the treatment of acne scars: A randomized split-face comparison study

BACKGROUND

Differences in clinical efficacy based on the fluence of fractional picosecond laser treatment for acne scars are unknown.

OBJECTIVE

To compare the efficacy and safety of low-fluence versus high-fluence fractional picosecond Nd:YAG 1064-nm laser treatment in acne scar patients.

METHODS

In this 12-week, investigator-blinded, randomized, split-face study, 25 patients with moderate-to-severe acne scars received three sessions of high-fluence laser treatment (1.0 J/cm2 ) on one side of their face and low-fluence (0.3 J/cm2 ) on the other side every 4 weeks. Patients were assessed using acne scar counts, the scar global assessment (SGA), and the ECCA scar grading scale every 4 weeks. The histological analysis compared the acne scars obtained before and 4 weeks after treatment.

RESULTS

At their last visit, 88.00% and 92.00% of the subjects achieved >30% reduction in scar counts on the low- and high-fluence sides, respectively, without a significant difference between the two sides. On both sides, the scar counts, SGA, and ECCA score significantly improved 4 weeks after the last treatment. Although the high-fluence side showed a greater reduction in scar counts (-66.73%) than the low-fluence side (-62.13%), the two sides had no significant difference in the grading scores. The high-fluence side showed significantly more severe pain and higher side-effect scores immediately and 4 weeks after treatment. Histological analysis revealed a significantly increased collagen, elastin, and vimentin expression after treatment on the low-fluence side.

CONCLUSIONS

The low-fluence setting demonstrated comparable efficacy and superior safety in treating acne scars compared with the high-fluence setting.

A cell-free, biomimetic hydrogel based on probiotic membrane vesicles ameliorates wound healing

Probiotic bacteria, such as Lactobacilli, have been shown to elicit beneficial effects in various tissue regeneration applications. However, their formulation as living bacteria is challenging, and their therapeutic use as proliferating microorganisms is especially limited in immunocompromised patients. Here, we propose a new therapeutic avenue to circumvent these shortcomings by developing a bacteriomimetic hydrogel based on membrane vesicles (MVs) produced by Lactobacilli. We coupled MVs from Lactobacillus plantarum and Lactobacillus casei, respectively, to the surface of synthetic microparticles, and embedded those bacteriomimetics into a pharmaceutically applicable hydrogel matrix. The wound microenvironment changes during the wound healing process, including adaptions of the pH and changes of the oxygen supply. We thus performed proteomic characterization of the MVs harvested under different culture conditions and identified characteristic proteins related to the biological effect of the probiotics in every culture state. In addition, we highlight a number of unique proteins expressed and sorted into the MVs for every culture condition. Using different in vitro models, we demonstrated that increased cell migration and anti-inflammatory effects of the bacteriomimetic microparticles were dependent on the culture condition of the secreting bacteria. Finally, we demonstrated the bacteriomimetic hydrogel's ability to improve healing in an in vivo mouse full-thickness wound model. Our results create a solid basis for the future application of probiotic-derived vesicles in the treatment of inflammatory dispositions and stimulates the initiation of further preclinical trials.

Antifibrotic properties of hyaluronic acid crosslinked polyisocyanide hydrogels

Fibrosis is characterized by the formation of fibrous connective tissue in response to primary injury. As a result, an affected organ may lose part of its functionality due to chronic, organ-specific tissue damage. Since fibrosis is a leading cause of death worldwide, targeting fibrotic diseases with antifibrotic hydrogels can be a lifesaving therapeutic strategy. This study developed a novel hybrid antifibrotic hydrogel by combining the synthetic polyisocyanide (PIC) with hyaluronic acid (HA). Gels of PIC are highly tailorable, thermosensitive, and strongly biomimetic in architecture and mechanical properties, whereas HA is known to promote non-fibrotic fetal wound healing and inhibits inflammatory signaling. The developed HA-PIC hybrids were biocompatible with physical properties comparable to those of the PIC gels. The antifibrotic nature of the gels was assessed by 3D cultures of human foreskin fibroblasts in the presence (or absence as control) of TGFβ1 that promotes differentiation into myofibroblasts, a critical step in fibrosis. Proliferation and macroscopic contraction assays and studies on the formation of stress fibers and characteristic fibrosis markers all indicate a strong antifibrotic nature of HA-PIC hydrogel. We showed that these effects originate from both the lightly crosslinked architecture and the presence of HA itself. The hybrid displaying both these effects shows the strongest antifibrotic nature and is a promising candidate for use as in vivo treatment for skin fibrosis.

Biophysical control of plasticity and patterning in regeneration and cancer

Cells and tissues display a remarkable range of plasticity and tissue-patterning activities that are emergent of complex signaling dynamics within their microenvironments. These properties, which when operating normally guide embryogenesis and regeneration, become highly disordered in diseases such as cancer. While morphogens and other molecular factors help determine the shapes of tissues and their patterned cellular organization, the parallel contributions of biophysical control mechanisms must be considered to accurately predict and model important processes such as growth, maturation, injury, repair, and senescence. We now know that mechanical, optical, electric, and electromagnetic signals are integral to cellular plasticity and tissue patterning. Because biophysical modalities underly interactions between cells and their extracellular matrices, including cell cycle, metabolism, migration, and differentiation, their applications as tuning dials for regenerative and anti-cancer therapies are being rapidly exploited. Despite this, the importance of cellular communication through biophysical signaling remains disproportionately underrepresented in the literature. Here, we provide a review of biophysical signaling modalities and known mechanisms that initiate, modulate, or inhibit plasticity and tissue patterning in models of regeneration and cancer. We also discuss current approaches in biomedical engineering that harness biophysical control mechanisms to model, characterize, diagnose, and treat disease states.

The Molecular Mechanisms Involved in the Hypertrophic Scars Post-Burn Injury

Scar formation is a normal response to skin injuries. During the scar-remodeling phase, scar tissue is usually replaced with normal, functional tissue. However, after deep burn injuries, the scar tissue may persist and lead to contractures around joints, a condition known as hypertrophic scar tissue. Unfortunately, current treatment options for hypertrophic scars, such as surgery and pressure garments, often fail to prevent their reappearance. One of the primary challenges in treating hypertrophic scars is a lack of knowledge about the molecular mechanisms underlying their formation. In this review, we critically analyze studies that have attempted to uncover the molecular mechanisms behind hypertrophic scar formation after severe burn injuries, as well as clinical trials conducted to treat post-burn hypertrophic scars. We found that most clinical trials used pressure garments, laser treatments, steroids, and proliferative inhibitors for hypertrophic scars, with outcomes measured using subjective scar scales. However, fundamental research using human burn injury biopsies has shown that pathways such as Transforming Growth factor β (TGFβ), Phosphatase and tensin homolog (PTEN), and Toll-like receptors (TLRs) could be potentially regulated to reduce scarring. Therefore, we conclude that more testing is necessary to determine the efficacy of these molecular targets in reducing hypertrophic scarring. Specifically, double-blinded clinical trials are needed, where the outcomes can be measured with more robust quantitative molecular parameters.

Artificial dermis combined with skin grafting for the treatment of hand skin and soft tissue defects and exposure of bone and tendon

BACKGROUND

The recovery time of hand wounds is long, which can easily result in chronic and refractory wounds, making the wounds unable to be properly repaired. The treatment cycle is long, the cost is high, and it is prone to recurrence and disability. Double layer artificial dermis combined with autologous skin transplantation has been used to repair hypertrophic scars, deep burn wounds, exposed bone and tendon wounds, and post tumor wounds.

AIM

To investigate the therapeutic efficacy of autologous skin graft transplantation in conjunction with double-layer artificial dermis in treating finger skin wounds that are chronically refractory and soft tissue defects that expose bone and tendon.

METHODS

Sixty-eight chronic refractory patients with finger skin and soft tissue defects accompanied by bone and tendon exposure who were admitted from July 2021 to June 2022 were included in this study. The observation group was treated with double layer artificial dermis combined with autologous skin graft transplantation (n = 49), while the control group was treated with pedicle skin flap transplantation (n = 17). The treatment status of the two groups of patients was compared, including the time between surgeries and hospital stay. The survival rate of skin grafts/flaps and postoperative wound infections were evaluated using the Vancouver Scar Scale (VSS) for scar scoring at 6 mo after surgery, as well as the sensory injury grading method and two-point resolution test to assess the recovery of skin sensation at 6 mo. The satisfaction of the two groups of patients was also compared.

RESULTS

Wound healing time in the observation group was significantly longer than that in the control group (P < 0.05, 27.92 ± 3.25 d vs 19.68 ± 6.91 d); there was no significant difference in the survival rate of skin grafts/flaps between the two patient groups (P > 0.05, 95.1 ± 5.0 vs 96.3 ± 5.6). The interval between two surgeries (20.0 ± 4.3 d) and hospital stay (21.0 ± 10.1 d) in the observation group were both significantly shorter than those in the control group (27.5 ± 9.3 d) and (28.4 ± 17.7 d), respectively (P < 0.05). In comparison to postoperative infection (23.5%) and subcutaneous hematoma (11.8%) in the control group, these were considerably lower at (10.2%) and (6.1%) in the observation group. When comparing the two patient groups at six months post-surgery, the excellent and good rate of sensory recovery (91.8%) was significantly higher in the observation group than in the control group (76.5%) (P < 0.05). There was also no statistically significant difference in two point resolution (P > 0.05). The VSS score in the observation group (2.91 ± 1.36) was significantly lower than that in the control group (5.96 ± 1.51), and group satisfaction was significantly higher (P < 0.05, 90.1 ± 6.3 vs 76.3 ± 5.2).

CONCLUSION

The combination of artificial dermis and autologous skin grafting for the treatment of hand tendon exposure wounds has a satisfactory therapeutic effect. It is a safe, effective, and easy to operate treatment method, which is worthy of clinical promotion.

The upregulation of circFoxp1 influences keloid by promoting cell proliferation

As a result of abnormal wound healing in susceptible individuals, keloids are characterized by hyperproliferation of fibroblasts and excessive deposition of the extracellular matrix (ECM). Current surgical and therapeutic modalities provide limited satisfactory results. Circular ribonucleic acids (circRNAs) play a crucial role in the pathogenesis of various fibrotic diseases, but the potential biological function and expression profile of circRNAs in keloid formation remain unknown. In this study, we explored the function of circFoxp1 on keloid formation. Methods: Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) results revealed that circFoxp1 expression was higher in the keloid tissues. Furthermore, RNA-fluorescence in situ hybridization (RNA-FISH) and RNAscope illustrated that circFoxp1 was present in the cytoplasm. Subsequent cellular experiments demonstrated that circFoxp1 overexpression enhanced proliferation, migration, and ECM deposition. In addition, apoptosis was inhibited. Cell proliferation, inflammatory response, and oxidative phosphorylation of fibroblasts were also observed by RNA sequencing and were closely related to scar formation. The therapeutic potential of circFoxp1 was investigated by establishing keloid implantation models. In vivo, circFoxp1 can promote fibroblast proliferation and ECM deposition. RNA pull-down and western blot assays verified the interaction of circFoxp1 with RACK1. The present study reveals that circFoxp1 contributes to the pathological hyperplasia of keloid, which may improve inflammation and cell proliferation. Our data indicate that circFoxp1 may serve as a novel, promising therapeutic target, presenting a new avenue for understanding the underlying pathogenesis of keloid.