Wound healing and scar wars

Ultrasound-assisted H2O2 degradation enhances the bioactivity of Schizophyllan for wound healing and tissue regeneration

Background

Schizophyllan (SPG), a bioactive polysaccharide from Schizophyllum commune, possesses significant anti-inflammatory, antioxidant, and immunomodulatory properties. The molecular weight of polysaccharides significantly impacts their structural properties and biological functions. However, the functional characteristics of low molecular weight polysaccharides derived from Schizophyllum commune remain inadequately explored.

Methods

This study developed an ultrasound-assisted hydrogen peroxide (H2O2) degradation method to produce low-molecular-weight SPG with enhanced bioactivity. The process was optimized using response surface methodology, focusing on ultrasound duration, ultrasonic power, and H2O2 concentration. This approach effectively reduced the molecular weight of SPG from 4,409,608 Da to 257,500 Da, yielding three distinct variants: SPG-a (257,500 Da), SPG-b (429,300 Da), and SPG-c (364,800 Da). The bioactivity of these variants was assessed through in vitro cell proliferation and migration assays using BJ and HaCaT cells, as well as an in vivo zebrafish larval caudal fin regeneration model.

Results

In vitro, SPG-b significantly promoted cell proliferation, increasing BJ and HaCaT cells growth by 53.69% and 14.59%, respectively, at a concentration of 300 μg/mL (p < 0.05), compared to undegraded SPG. Additionally, scratch assays revealed that SPG-a enhanced BJ cells migration by 24.13% (p < 0.05), while SPG-b exhibited most pronounced effect on HaCaT cells migration (17.12%, p < 0.05), compared to the undegraded SPG. In vivo, SPG-c (3.125 mg/mL) significantly improved fin regeneration rates by 6.97% (p < 0.05) in zebrafish larvae, compared to the undegraded SPG.

Conclusion

This study demonstrates that ultrasound-assisted H2O2 degradation effectively reduces SPG molecular weight while enhancing its functional properties. These findings provide a foundation for the further development of SPG in pharmaceutical and cosmetic applications, highlighting its potential for broader utilization.

Molecular profiling of skin cells identifies distinct cellular signatures in radiation-induced skin injury across various stages in the murine dataset

BACKGROUND

Radiation-induced skin injury (RISI) commonly manifests in cancer patients undergoing radiotherapy (RT). However, a universally accepted standard for treating radiation injury has not yet been established. Our objective was to provide a detailed molecular overview of skin pre- and post-radiation therapy, aiming to enhance our understanding of the subclusters and molecular mechanisms contributing to radiodermatitis.

METHODS

C57BL/6 mice were subjected to a single fraction (20 Gy) of RT targeting the right dorsal skin. We then employed integrated single-cell RNA sequencing (scRNA-seq) to analyze skin samples from mice at 7 and 30 days after radiation exposure, as well as from non-irradiated mice. The Seurat analysis pipeline, Cellchat, SCP, and ssGSEA were used to define the cell types and mechanisms involved in radiation-induced skin injury. Reverse transcription polymerase chain reaction (RT-PCR), multiplex immunofluorescent staining, and other datasets (GSE130183, GSE193564, and GSE193807) were used to validate our findings.

RESULTS

Thirty-two distinct cell clusters encompassing 71,412 cells were identified. We discovered that cycling keratinocytes (KCs), with the BMP signaling pathway enriched, could activate the Wnt pathway, as well as the SMAD pathways, driving the wound healing and fibrosis processes in RISI. Terminally differentiated secretory-papillary fibroblasts (Fibs) are capable of attracting immune cells, which contributes to the pathogenesis of RISI. Lymphatic endothelial cells (ECs) with pro-inflammatory properties play a critical role in the pathogenesis of RISI by facilitating leukocyte migration. Our analysis also highlighted enhanced ligand-receptor interactions, notably the interactions between chemokines like CXCL10, CCL2, and ACKR1, across subclusters of inflammatory KCs, Fibs, ECs, and immune cells, underscoring their pivotal role in leukocyte recruitment in RISI.

CONCLUSIONS

Cycling KCs, secretory-papillary Fibs, and lymphatic ECs play critical roles in RISI progression. Targeting the interactions of these subclusters with immune cells might help improve the severity of RISI. Furthermore, our study provides a valuable resource for understanding the interactions among immune cells in the context of RISI.

Advances of exosomes in diabetic wound healing

Poor wound healing is a refractory process that places an enormous medical and financial burden on diabetic patients. Exosomes have recently been recognized as crucial players in the healing of diabetic lesions. They have excellent stability, homing effects, biocompatibility, and reduced immunogenicity as novel cell-free therapies. In addition to transporting cargos to target cells to enhance intercellular communication, exosomes are beneficial in nearly every phase of diabetic wound healing. They participate in modulating the inflammatory response, accelerating proliferation and reepithelization, increasing angiogenesis, and regulating extracellular matrix remodeling. Accumulating evidence indicates that hydrogels or dressings in conjunction with exosomes can prolong the duration of exosome residency in diabetic wounds. This review provides an overview of the mechanisms, delivery, clinical application, engineering, and existing challenges of the use of exosomes in diabetic wound repair. We also propose future directions for biomaterials incorporating exosomes: 2D or 3D scaffolds, biomaterials loaded with wound healing-promoting gases, intelligent biomaterials, and the prospect of systematic application of exosomes. These findings may might shed light on future treatments and enlighten some studies to improve quality of life among diabetes patients.

Differential Oral Microbiota and Serum Cytokine Signatures in Age-Grouped Patients with Marfan Syndrome

Introduction: Marfan syndrome (MFS) is an autosomal dominant genetic disorder, caused by a mutation in the FBN-1 gene, affecting the cardiovascular, musculoskeletal, ocular, and central nervous systems. Cardiovascular abnormalities associated with MFS lead to different pathological conditions, such as cardiac arrhythmias, coronary artery disease, and aortic dilatation. The latter are the primary causes of mortality in MFS patients. To date, the role of altered oral microbiota (OM) in MFS is unknown, and so the aim of our study was to determine whether there are differences in the oral microbiota of MFS patients with aortic dilatation and non-dilatation. Methods: We enrolled 36 MFS patients, who were divided into groups with aortic non-dilatation (n = 12) and with aortic dilatation (n = 24). Dental plaque samples were used for OM analysis, and serum was used for cytokine evaluation. Results: The main genera were compared between patients with aortic dilatation and non-dilatation, revealing three genera with significant differences: Actinomyces (p = 0.007) and Rothia (p = 0.002) were more abundant in those with aortic dilatation, while Fusobacterium (p = 0.044) was more abundant in non-dilatation patients. However, no significant differences in cytokine levels were observed between the presence and absence of aortic dilatation, except that the IL-1β levels were higher in non-dilatation patients (165.09 pg/mL) than in those with dilatation (117.15 pg/mL), with a significance of p = 0.057. Conclusions: This study represents the initial, tentative pilot study to understand the relationship between oral health and systemic conditions in patients with Marfan syndrome.

Systemic factors associated with antler growth promote complete wound healing

Deer antlers are the only mammalian appendages that can fully regenerate from periosteum of pedicles (PP). This regeneration process starts from regenerative healing of wounds. Removal of PP abolishes antler regeneration, however, the regenerative cutaneous wound healing proceeds, indicating that some factors in the circulation contribute to this healing. In this study, we produced a wound in the scalp of deer either in antler regeneration period (ARP) (n = 3) or in non-ARP (n = 3). Results showed full regeneration took place only when the wound was created during ARP. Interestingly, topical application of systemic factors from ARP (n = 9) promoted regenerative wound healing in rats. Comparative proteomics analysis (n = 3) revealed that PRG4 and IGF-1 were high during ARP, and topical application of PRG4 + IGF-1 promoted restoration in rat FTE wounds. We believe that, ultimately, incorporating systemic factors into advanced wound care modalities could offer new opportunities for regenerative healing in the clinical setting.

Specific Non-Coding RNAs Involve in and Regulate the Transcriptional Network during Keloid Formation

Keloid formation is an undesirable outcome of wound healing and is detrimental to patients' physical and mental health, while the molecular regulators of its pathogenesis, especially non-coding RNAs (ncRNAs), are largely unknown. In this study, we integrated and analyzed RNA-seq and miRNA microarray datasets of skin samples from keloid-prone and healthy normal individuals to detect the dysregulated long ncRNAs (lncRNAs) and miRNAs. We excavated 583 and 104 keloid-specific lncRNAs and miRNAs, respectively. Moreover, the molecular functions of these ln-cRNAs and miRNAs are all related to ossification. Next, we constructed the relationship between lncRNAs and immune cell infiltration, and found the macrophages, NK cells, and dendritic cells were specifically dysregulated in keloid-prone or normal groups during wound healing. We constructed the potential regulatory network between these cell types and 20 dysregulated lncRNAs, suggesting their regulatory function in keloid formation. At last, we constructed the competitive endogenous RNA network and found two hub lncRNAs and five miRNAs, including DLEU1 and SLC25A21-AS1, miR-197-5p, miR-940, miR-6765-5p, miR-711, and miR-4284, which were highly dysregulated during keloid formation. In summary, these results demonstrate that lncRNAs and miRNAs play important roles and form a regulatory network in the pathogenesis, immune infiltration, and development of keloid formation.

Deficiency of SECTM1 impairs corneal wound healing in aging

The corneal epithelium is the outermost transparent barrier of the eyeball and undergoes continuous self-renewal by limbal stem cells (LSCs) during its lifetime; however, the impact of aging on LSCs remains largely unknown. Here, we showed that the healing ability of the cornea in elderly macaques (Macaca fascicularis) was significantly decreased compared to that of younger macaques. This delayed wound closure accompanied a disordered cell arrangement and corneal opacity. A novel cytokine, Secreted and Transmembrane 1 (SECTM1), was found to facilitate corneal healing and was upregulated in young macaques upon wounding. Mechanistically, SECTM1 is essential for LSC migration and proliferation, and may partially function through Cell Division Cycle Associated 7 (CDCA7). Notably, the topical application of SECTM1 to aged wounded corneas dramatically promoted re-epithelialization and improved corneal transparency in both mice and macaques. Our work suggests that aging may impair the expression of healing response factors and injury repair in non-human primate corneas, and that SECTM1 application could potentially benefit corneal wound healing in clinical treatment.

SPRR1B+ keratinocytes prime oral mucosa for rapid wound healing via STAT3 activation

Oral mucosal wounds exhibit accelerated healing with reduced scarring compared to cutaneous wounds, representing an optimal wound healing paradigm. However, the specific cellular subtypes orchestrating the efficient healing of mucosal tissues remain elusive. Through a comprehensive analysis integrating bulk-mRNA and single-cell sequencing data during the wound healing process in oral mucosa and skin, we have delineated a distinct set of genes markedly upregulated during tissue repair. This collection of wound healing-associated genesets was highly enriched in a specific keratinocyte subpopulation identified as STAT3-activated SPRR1B+ keratinocytes. Notably, despite the inherent rapidity of oral mucosal healing, the induction of SPRR1B+ keratinocytes is evident in both skin and mucosal wound healing processes in murine model. Intriguingly, these wound healing-promoting SPRR1B+ keratinocytes, which are induced via STAT3 activation, inherently abundant in unwounded normal mucosa but absent in normal skin. SPRR1B knockdown significantly inhibits mucosal keratinocyte migration, a critical attribute for effective wound healing. In summary, through analysis of human oral and skin wound healing processes at single-cell resolution, coupled with validation in murine model, suggests STAT3-activated SPRR1B+ keratinocytes are associated with the rapid mucosal repair process. This discovery underscores the potential application of SPRR1B+ keratinocytes in the therapeutic management of chronic or non-healing wounds.

IL-17 in wound repair: bridging acute and chronic responses

Chronic wounds, resulting from persistent inflammation, can trigger a cascade of detrimental effects including exacerbating inflammatory cytokines, compromised blood circulation at the wound site, elevation of white blood cell count, increased reactive oxygen species, and the potential risk of bacterial infection. The interleukin-17 (IL-17) signaling pathway, which plays a crucial role in regulating immune responses, has been identified as a promising target for treating inflammatory skin diseases. This review aims to delve deeper into the potential pathological role and molecular mechanisms of the IL-17 family and its pathways in wound repair. The intricate interactions between IL-17 and other cytokines will be discussed in detail, along with the activation of various signaling pathways, to provide a comprehensive understanding of IL-17's involvement in chronic wound inflammation and repair.

Electrospun drug-loaded scaffolds for nervous system repair

Nervous system injuries, encompassing peripheral nerve injury (PNI), spinal cord injury (SCI), and traumatic brain injury (TBI), present significant challenges to patients' wellbeing. Traditional treatment approaches have limitations in addressing the complexity of neural tissue regeneration and require innovative solutions. Among emerging strategies, implantable materials, particularly electrospun drug-loaded scaffolds, have gained attention for their potential to simultaneously provide structural support and controlled release of therapeutic agents. This review provides a thorough exploration of recent developments in the design and application of electrospun drug-loaded scaffolds for nervous system repair. The electrospinning process offers precise control over scaffold characteristics, including mechanical properties, biocompatibility, and topography, crucial for creating a conducive environment for neural tissue regeneration. The large surface area of the resulting fibrous networks enhances biomolecule attachment, influencing cellular behaviors such as adhesion, proliferation, and migration. Polymeric electrospun materials demonstrate versatility in accommodating a spectrum of therapeutics, from small molecules to proteins. This enables tailored interventions to accelerate neuroregeneration and mitigate inflammation at the injury site. A critical aspect of this review is the examination of the interplay between structural properties and pharmacological effects, emphasizing the importance of optimizing both aspects for enhanced therapeutic outcomes. Drawing upon the latest advancements in the field, we discuss the promising outcomes of preclinical studies using electrospun drug-loaded scaffolds for nervous system repair, as well as future perspectives and considerations for their design and implementation. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Antler stem cell-derived exosomes promote regenerative wound healing via fibroblast-to-myofibroblast transition inhibition

INTRODUCTION

The typical outcome of mammalian wound healing is scarring, a fibrotic process mediated by myofibroblast aggregation. Perfect healing in a clinical setting is relatively unexplored. Surprisingly, our previous studies have shown that the large wound (10 cm diameter or more) of the pedicle of deer naturally achieves regenerative restoration, realized through a paracrine pathway from adjacent antler stem cells (AnSCs).

METHODS

AnSC-derived exosomes (AnSC-exos) were topically injected around the full-thickness wounds in a rat model. The effects on the rate of wound healing and the quality of healing were evaluated via morphological, histological, and molecular biological techniques on days 14 and 28 after surgery.

RESULTS

The results showed that AnSC-exos significantly accelerated the rate of wound healing and improved healing quality, including regeneration of cutaneous appendages (hair follicles and sebaceous glands) and the distribution pattern of collagen (basket-weave-like) in the healed skin. These effects of AnSC-exos were comparable to those of AnSCs but were significantly more potent than those of exosomes derived from bone marrow mesenchymal stem cells (bMSC-exos). Furthermore, AnSC-exos treatment effectively inhibited fibroblast-to-myofibroblast transition (FMT), as evidenced by the reduction of full-thickness skin injury-induced FMT in vivo and TGF-β1-induced FMT in vitro.

CONCLUSION

AnSC-exos could effectively promote regenerative cutaneous wound healing, highly likely through FMT inhibition. This suggests that AnSC-exos treatment could provide the potential for a novel approach to induce regenerative wound healing in the clinical setting.

Biodiversity of Skin Microbiota as an Important Biomarker for Wound Healing

Cutaneous wound healing is a natural and complex repair process that is implicated within four stages. However, microorganisms (e.g., bacteria) can easily penetrate through the skin tissue from the wound bed, which may lead to disbalance in the skin microbiota. Although commensal and pathogenic bacteria are in equilibrium in normal skin, their imbalance in the wound area can cause the delay or impairment of cutaneous wounds. Moreover, skin microbiota is in constant crosstalk with the immune system and epithelial cells, which has significance for the healing of a wound. Therefore, understanding the major bacteria species in the cutaneous wound as well as their communication with the immune system has gained prominence in a way that allows for the emergence of a new perspective for wound healing. In this review, the major bacteria isolated from skin wounds, the role of the crosstalk between the cutaneous microbiome and immune system to heal wounds, the identification techniques of these bacteria populations, and the applied therapies to manipulate the skin microbiota are investigated.

Lamprey Wound Healing and Regenerative Effects: The Collaborative Efforts of Diverse Drivers

Skin is a natural barrier between the body and the external environment, and this important multifunctional organ plays roles in body temperature regulation, sensory stimulation, mucus secretion, metabolite excretion and immune defense. Lampreys, as ancient vertebrates, rarely experience infection of damaged skin during farming and efficiently promote skin wound healing. However, the mechanism underlying these wound healing and regenerative effects is unclear. Our histology and transcriptomics results demonstrate that lampreys regenerate a nearly complete skin structure in damaged epidermis, including the secretory glands, and will almost not be infected, even if experiencing full-thickness damage. In addition, ATGL, DGL and MGL participate in the lipolysis process to provide space for infiltrating cells. A large number of red blood cells migrate to the site of injury and exert proinflammatory effects, upregulating the expression of proinflammatory factors such as IL-8 and IL-17. Based on a lamprey skin damage healing model, adipocytes and red blood cells in the subcutaneous fat layer can promote wound healing, which provides a new approach for the study of skin healing mechanisms. Transcriptome data reveal that mechanical signal transduction pathways are mainly regulated by focal adhesion kinase and that the actin cytoskeleton plays an important role in the healing of lamprey skin injuries. We identified RAC1 as a key regulatory gene that is necessary and partially sufficient for wound regeneration. Insights into the mechanisms of lamprey skin injury and healing will provide a theoretical basis for overcoming the challenges associated with chronic healing and scar healing in the clinic.

The initiation of oxidative stress and therapeutic strategies in wound healing

When the production of reactive oxygen species (ROS) is overloaded surpassing the capacity of the reductive rheostat, mammalian cells undergo a series of oxidative damage termed oxidative stress (OS). This phenomenon is ubiquitously detected in many human pathological conditions. Wound healing program implicates continuous neovascularization, cell proliferation, and wound remodeling. Increasing evidence indicates that reactive oxygen species (ROS) have profound impacts on the wound healing process through regulating a series of the physiological and pathological program including inflammatory response, cell proliferation, angiogenesis, granulation as well as extracellular matrix formation. In most pathological wound healing processes, excessive ROS exerts a negative role on the wound healing process. Interestingly, the moderate increase of ROS levels is beneficial in killing bacteria at the wound site, which creates a sterile niche for revascularization. In this review, we discussed the physiological rhythms of wound healing and the role of ROS in this progress, aim to explore the potential manipulation of OS as a promising therapeutic avenue.

3D bioprinted mesenchymal stromal cells in skin wound repair

Skin tissue regeneration and repair is a complex process involving multiple cell types, and current therapies are limited to promoting skin wound healing. Mesenchymal stromal cells (MSCs) have been proven to enhance skin tissue repair through their multidifferentiation and paracrine effects. However, there are still difficulties, such as the limited proliferative potential and the biological processes that need to be strengthened for MSCs in wound healing. Recently, three-dimensional (3D) bioprinting has been applied as a promising technology for tissue regeneration. 3D-bioprinted MSCs could maintain a better cell ability for proliferation and expression of biological factors to promote skin wound healing. It has been reported that 3D-bioprinted MSCs could enhance skin tissue repair through anti-inflammatory, cell proliferation and migration, angiogenesis, and extracellular matrix remodeling. In this review, we will discuss the progress on the effect of MSCs and 3D bioprinting on the treatment of skin tissue regeneration, as well as the perspective and limitations of current research.

"Jianbing" styling multifunctional electrospinning composite membranes for wound healing

Wound infection and excessive exudate can affect the process of wound healing. However, the disadvantage of the anti-microbial wound dressings is that the biological fluids are ineffectively removed. Inspired by making "Chinese Jianbing", a composite wound nano-dressing was developed consisting of a hydrophilic outer layer (chitosan&polyvinyl alcohol: CTS-PVA) and a hydrophobic inner layer (propolis&polycaprolactone: PRO-PCL) by combining casting and electrospinning methods for effective antibacterial and unidirectional removing excess biofluids. In vitro, the composite wound nano-dressing of PRO-PCL and CTS-PVA (PPCP) could strongly inhibit Pseudomonas aeruginosa. Furthermore, PPCP wound dressing had excellent antioxidant properties and blood coagulation index for effective hemostatic. Importantly, it had a preferable water absorption for removing excess biofluid. In vivo, it had anti-inflammatory properties and promoted collagen Ⅰ preparation, which realized 80% wound healing on day 7. In short, the PPCP wound dressing provides a new direction and option for antibacterial and removes excess biofluid.

Velvet Antler Peptides Reduce Scarring via Inhibiting the TGF-β Signaling Pathway During Wound Healing

AIM

Scar formation generally occurs in cutaneous wound healing in mammals, mainly caused by myofibroblast aggregations, and currently with few effective treatment options. However, the pedicle wound (about 10 cm in diameter) of the deer can initiate regenerative healing, which has been found to be achieved via paracrine factors from the internal tissues of antlers.

METHODS

Enzymatically digested velvet antler peptides (EVAP) were prepared along with other types of antler extracts as the controls. The effects of EVAP on healing of full-thickness skin wounds were evaluated using rats in vivo, and on myofibroblast transdifferentiation tested using transforming growth factor-β1 (TGF-β1)-induced human dermal fibroblasts in vitro.

RESULTS

EVAP significantly accelerated the wound healing rate, reduced scar formation, and improved the healing quality, including promoted angiogenesis, increased number of skin appendages (hair follicles and sebaceous glands) and improved the distribution pattern of collagen fibers (basket-wave like) in the healed tissue. Moreover, EVAP significantly down-regulated the expression levels of genes pro- scar formation (Col1a2 and TGF-β1), and up-regulated the expression levels of genes anti-scar formation (Col3a1 and TGF-β3), and suppressed the excessive transdifferentiation of myofibroblasts and the formation of collagen I in vivo and in vitro. Furthermore, we found these effects were highly likely achieved by inhibiting the TGF-β signaling pathway, evidenced by decreased expression levels of the related genes, including TGF-β1, Smad2, p-Smad2, α-SMA, and collagen I.

CONCLUSIONS

EVAP may be a promising candidate to be developed as a clinic drug for regenerative wound healing.

Biomimetic immunomodulation strategies for effective tissue repair and restoration

Inflammation plays a central role in wound healing following injury or disease and is mediated by a precise cascade of cellular and molecular events. Unresolved inflammatory processes lead to chronic inflammation and fibrosis, which can result in prolonged wound healing lasting months or years that hampers tissue function. Therapeutic interventions mediated by immunomodulatory drugs, cells, or biomaterials, are therefore most effective during the inflammatory phase of wound healing when a pro-regenerative environment is essential. In this review, we discuss the advantages of exploiting knowledge of the native tissue microenvironment to develop therapeutics capable of modulating the immune response and promoting functional tissue repair. In particular, we provide examples of the most recent biomimetic platforms proposed to accomplish this goal, with an emphasis on those able to induce macrophage polarization towards a pro-regenerative phenotype.

Deciphering the role of cartilage protein 1 in human dermal fibroblasts: a transcriptomic approach

Cartilage acidic protein 1A (hCRTAC1-A) is an extracellular matrix protein (ECM) of human hard and soft tissue that is associated with matrix disorders. The central role of fibroblasts in tissue integrity and ECM health made primary human dermal fibroblasts (NHDF) the model for the present study, which aimed to provide new insight into the molecular function of hCRTAC1-A. Specifically, we explored the differential expression patterns of specific genes associated with the presence of hCRTAC1-A by RNA-seq and RT-qPCR analysis. Functional enrichment analysis demonstrated, for the very first time, that hCRTAC1-A is involved in extracellular matrix organization and development, through its regulatory effect on asporin, decorin, and complement activity, in cell proliferation, regeneration, wound healing, and collagen degradation. This work provides a better understanding of putative hCRTAC1-A actions in human fibroblasts and a fundamental insight into its function in tissue biology.

Programmable immune activating electrospun fibers for skin regeneration

Immune cells play a crucial regulatory role in inflammatory phase and proliferative phase during skin healing. How to programmatically activate sequential immune responses is the key for scarless skin regeneration. In this study, an "Inner-Outer" IL-10-loaded electrospun fiber with cascade release behavior was constructed. During the inflammatory phase, the electrospun fiber released a lower concentration of IL-10 within the wound, inhibiting excessive recruitment of inflammatory cells and polarizing macrophages into anti-inflammatory phenotype "M2c" to suppress excessive inflammation response. During the proliferative phase, a higher concentration of IL-10 released by the fiber and the anti-fibrotic cytokines secreted by polarized "M2c" directly acted on dermal fibroblasts to simultaneously inhibit extracellular matrix overdeposition and promote fibroblast migration. The "Inner-Outer" IL-10-loaded electrospun fiber programmatically activated the sequential immune responses during wound healing and led to scarless skin regeneration, which is a promising immunomodulatory biomaterial with great potential for promoting complete tissue regeneration.

Smart graphene-based hydrogel promotes recruitment and neural-like differentiation of bone marrow derived mesenchymal stem cells in rat skin

Strategies to direct the differentiation of endogenous bone marrow derived mesenchymal stem cells (BMSCs) in vivo following recruitment to the injured site are critical to realizing the potential of stem cell-based therapies. But the differentiation efficiency of BMSCs remains limited without direction. Here we demonstrated a novel strategy to promote neuronal differentiation of BMSCs using cross-linked polyethylenimine (PEI) grafted graphene oxide (GO) as the enzyme responsive vector for delivering active genes to BMSCs. In vivo, a core-shell microfiber arrayed hydrogel with a chemokine (SDF-1α) and the cross-linked GO-PEI/pDNAs-bFGF microparticles incorporated into the shell and core, respectively, were constructed. The arrayed hydrogel was shown to recruit and stimulate the neural-like differentiation of BMSCs effectively by delivering the CXCL12 and GO-PEI/pDNAs-bFGF in a self-controlled manner. With this strategy, both in vitro and in vivo neuronal differentiation of BMSCs with function were accelerated significantly. The cross-linked GO-PEI mediated gene transfection together with a multi-functional microfiber arrayed hydrogel provide a translatable approach for endogenous stem cell-based regenerative therapy.

Wound dressings as growth factor delivery platforms for chronic wound healing

Introduction: Years of tissue engineering research have clearly demonstrated the potential of integrating growth factors (GFs) into scaffolds for tissue regeneration, a concept that has recently been applied to wound dressings. The old concept of wound dressings that only take a passive role in wound healing has now been overtaken, and advanced dressings which can take an active part in wound healing, are of current research interest.Areas covered: In this review we will focus on the recent strategies for the delivery of GFs to wound sites with an emphasis on the different approaches used to achieve fine tuning of spatial and temporal concentrations to achieve therapeutic efficacy.Expert opinion: The use of GFs to accelerate wound healing and reduce scar formation is now considered a feasible therapeutic approach in patients with a high risk of infections and complications. The integration of micro - and nanotechnologies into wound dressings could be the key to overcome the inherent instability of GFs and offer adequate control over the release rate. Many investigations have led to encouraging outcomes in various in vitro and in vivo wound models, and it is expected that some of these technologies will satisfy clinical needs and will enter commercialization.

The extracellular matrix as a multitasking player in disease

Extracellular matrices (ECMs) are highly specialized and dynamic three-dimensional (3D) scaffolds into which cells reside in tissues. ECM is composed of a variety of fibrillar components, such as collagens, fibronectin, and elastin, and non-fibrillar molecules as proteoglycans, hyaluronan, and glycoproteins including matricellular proteins. These macromolecular components are interconnected forming complex networks that actively communicate with cells through binding to cell surface receptors and/or matrix effectors. ECMs exert diverse roles, either providing tissues with structural integrity and mechanical properties essential for tissue functions or regulating cell phenotype and functions to maintain tissue homeostasis. ECM molecular composition and structure vary among tissues, and is markedly modified during normal tissue repair as well as during the progression of various diseases. Actually, abnormal ECM remodeling occurring in pathologic circumstances drives disease progression by regulating cell-matrix interactions. The importance of matrix molecules to normal tissue functions is also highlighted by mutations in matrix genes that give rise to genetic disorders with diverse clinical phenotypes. In this review, we present critical and emerging issues related to matrix assembly in tissues and the multitasking roles for ECM in diseases such as osteoarthritis, fibrosis, cancer, and genetic diseases. The mechanisms underlying the various matrix-based diseases are also discussed. Research focused on the highly dynamic 3D ECM networks will help to discover matrix-related causative abnormalities of diseases as well as novel diagnostic tools and therapeutic targets.