Porous polymer scaffold for on-site delivery of stem cells--Protects from oxidative stress and potentiates wound tissue repair

Functional poly(e-caprolactone)/SerMA hybrid dressings with dimethyloxalylglycine-releasing property improve cutaneous wound healing

Medical dressings with multifunctional properties, including potent regeneration capability and good biocompatibility, are increasingly needed in clinical practice. In this study, we reported a novel hybrid wound dressing (PCL/SerMA/DMOG) that combines electrospun PCL membranes with DMOG-loaded methacrylated sericin (SerMA) hydrogel. In such a design, DMOG molecules are released from the hybrid dressing in a sustained mannerin vitro. A series ofin vitroassays demonstrated that DMOG-loaded hybrid dressing has multiple biological functions, including promotion of human umbilical vein endothelial cells proliferation and migration,in vitrovascularization, and the generation of intracellular NO. When applied to the cutaneous wound, the PCL/SerMA/DMOG dressing significantly accelerated wound closure and tissue regeneration by promoting angiogenesis in the wound area, collagen deposition, and cell proliferation within the wound bed. These results highlight the potential clinical application of PCL/SerMA/DMOG hybrid dressings as promising alternatives for accelerating wound healing via improved biocompatibility and angiogenesis amelioration.

3D Porous Polymer Scaffold-Conjugated KGF-Mimetic Peptide Promotes Functional Skin Regeneration in Chronic Diabetic Wounds

The re-epithelialization process gets severely dysregulated in chronic nonhealing diabetic foot ulcers/wounds. Keratinocyte growth factor (KGF or FGF-7) is the major modulator of the re-epithelialization process, which regulates the physiological phenotypes of cutaneous keratinocytes. The existing therapeutic strategies of growth factor administration have several limitations. To overcome these, we have designed a KGF-mimetic peptide (KGFp, 13mer) based on the receptor interaction sites in murine KGF. KGFp enhanced migration and transdifferentiation of mouse bone marrow-derived MSCs toward keratinocyte-like cells (KLCs). A significant increase in the expression of skin-specific markers Bnc1 (28.5-fold), Ck5 (14.6-fold), Ck14 (26.1-fold), Ck10 (187.7-fold), and epithelial markers EpCam (23.3-fold) and Cdh1 (64.2-fold) was associated with the activation of ERK1/2 and STAT3 molecular signaling in the KLCs. Further, to enhance the stability of KGFp in the wound microenvironment, it was conjugated to biocompatible 3D porous polymer scaffolds without compromising its active binding sites followed by chemical characterization using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic mechanical analysis, and thermogravimetry. In vitro evaluation of the KGFp-conjugated 3D polymer scaffolds revealed its potential for transdifferentiation of MSCs into KLCs. Transplantation of allogeneic MSCGFP using KGFp-conjugated 3D polymer scaffolds in chronic nonhealing type 2 diabetic wounds (db/db transgenic, 50-52 weeks old male mice) significantly enhanced re-epithelialization-mediated wound closure rate (79.3%) as compared to the control groups (Untransplanted -22.4%, MSCGFP-3D polymer scaffold -38.5%). Thus, KGFp-conjugated 3D porous polymer scaffolds drive the fate of the MSCs toward keratinocytes that may serve as potential stem cell delivery platform technology for tissue engineering and transplantation.

Bioengineered MSCGFPCxcr2-Mmp13 Transplantation Alleviates Hepatic Fibrosis by Regulating Mammalian Target of Rapamycin Signaling

Aims: Hepatic fibrosis is the pathological change during chronic liver diseases (CLD) that turns into cirrhosis if not reversed timely. Allogenic mesenchymal stem cell (MSC) therapy is an alternative to liver transplantation for CLD. However, poor engraftment of the transplanted MSCs limits their therapeutic efficacy. MSCs express chemokine receptors that regulate their physiology. We observed several-fold increased expressions of Cxcl3 and decreased expression of Mmp13 in the fibrotic liver. Therefore, we bioengineered MSCs with stable overexpression of Cxcr2 (CXCL3-cognate receptor) and Mmp13, collagenase (MSCGFPCxcr2-Mmp13). Results: The CXCL3/CXCR2 axis significantly increased migration through the activation of AKT/ERK/mTOR signaling. These bioengineered MSCs transdifferentiated into hepatocyte-like cells (MSCGFPCxcr2-Mmp13-HLCs) that endured the drug-/hepatotoxicant-induced toxicity by significantly increasing the antioxidants-Nrf2 and Sod2, while decreasing the apoptosis-Cyt C, Casp3, Casp9, and drug-metabolizing enzyme-Cyp1A1, Cyp1A2, Cyp2E1 markers. Therapeutic transplantation of MSCGFPCxcr2-Mmp13 abrogated AAP-/CCl4-induced hepatic fibrosis in mice by CXCR2-mediated targeted engraftment and MMP-13-mediated reduction in collagen. Mechanistically, induction of CXCL3/CXCR2 axis-activated mTOR-p70S6K signaling led to increased targeted engraftment and modulation of the oxidative stress by increasing the expression and activity of nuclear Nrf2 and SOD2 expression in the regenerated hepatic tissues. A marked change in the fate of transplanted MSCGFPCxcr2-Mmp13 toward hepatocyte lineage demonstrated by co-immunostaining of GFP/HNF4α along with reduced COL1α1 facilitated the regeneration of the fibrotic liver. Innovation and Conclusions: Our study suggests the therapeutic role of allogenic Cxcr2/Mmp13-bioengineered MSC transplantation decreases the hepatic oxidative stress as an effective translational therapy for hepatic fibrosis mitigation-mediated liver regeneration.

Gases and gas-releasing materials for the treatment of chronic diabetic wounds

Chronic non-healing wounds are a common consequence of skin ulceration in diabetic patients, with severe cases such as diabetic foot even leading to amputations. The interplay between pathological factors like hypoxia-ischemia, chronic inflammation, bacterial infection, impaired angiogenesis, and accumulation of advanced glycosylation end products (AGEs), resulting from the dysregulation of the immune microenvironment caused by hyperglycemia, establishes an unending cycle that hampers wound healing. However, there remains a dearth of sufficient and effective approaches to break this vicious cycle within the complex immune microenvironment. Consequently, numerous scholars have directed their research efforts towards addressing chronic diabetic wound repair. In recent years, gases including Oxygen (O2), Nitric oxide (NO), Hydrogen (H2), Hydrogen sulfide (H2S), Ozone (O3), Carbon monoxide (CO) and Nitrous oxide (N2O), along with gas-releasing materials associated with them have emerged as promising therapeutic solutions due to their ability to regulate angiogenesis, intracellular oxygenation levels, exhibit antibacterial and anti-inflammatory effects while effectively minimizing drug residue-induced damage and circumventing drug resistance issues. In this review, we discuss the latest advances in the mechanisms of action and treatment of these gases and related gas-releasing materials in diabetic wound repair. We hope that this review can provide different ideas for the future design and application of gas therapy for chronic diabetic wounds.

Renewable Electroconductive Hydrogels for Accelerated Diabetic Wound Healing and Motion Monitoring

Diabetic foot ulcers (DFUs), a prevalent complication of diabetes mellitus, may result in an amputation. Natural and renewable hydrogels are desirable materials for DFU dressings due to their outstanding biosafety and degradability. However, most hydrogels are usually only used for wound repair and cannot be employed to monitor motion because of their inherent poor mechanical properties and electrical conductivity. Given that proper wound stretching is beneficial for wound healing, the development of natural hydrogel patches integrated with wound repair properties and motion monitoring was expected to achieve efficient and accurate wound healing. Here, we designed a dual-network (chitosan and sodium alginate) hydrogel embedded with lignin-Ag and quercetin-melanin nanoparticles to achieve efficient wound healing and motion monitoring. The double network formed by the covalent bond and electrostatic interaction confers the hydrogel with superior mechanical properties. Instead of the usual chemical reagents, genipin extracted from Gardenia was used as a cross-linking agent for the hydrogel and consequently improved its biosafety. Furthermore, the incorporation of lignin-Ag nanoparticles greatly enhanced the mechanical strength, antibacterial efficacy, and conductivity of the hydrogel. The electrical conductivity of hydrogels gives them the capability of motion monitoring. The motion sensing mechanism is that stretching of the hydrogel induced by motion changes the conductivity of the hydrogel, thus converting the motion into an electrical signal. Meanwhile, quercetin-melanin nanoparticles confer exceptional adhesion, antioxidant, and anti-inflammatory properties to the hydrogels. The system ultimately achieved excellent wound repair and motion monitoring performance and was expected to be used for stretch-assisted safe and accurate wound repair in the future.

Bioengineered MSCCxcr2 transdifferentiated keratinocyte-like cell-derived organoid potentiates skin regeneration through ERK1/2 and STAT3 signaling in diabetic wound

Skin regeneration is severely compromised in diabetic foot ulcers. Allogeneic mesenchymal stem cell (MSC) transplantation is limited due to the poor engraftment, mitogenic, and differentiation potential in the harsh wound microenvironment. Thus, to improve the efficacy of cell therapy, the chemokine receptor Cxcr2 was overexpressed in MSCs (MSCCxcr2). CXCL2/CXCR2 axis induction led to the enhanced proliferation of MSCs through the activation of STAT3 and ERK1/2 signaling. Transcriptional upregulation of FGFR2IIIb (KGF Receptor) promoter by the activated STAT3 and ERK1/2 suggested trans-differentiation of MSCs into keratinocytes. These stable MSCCxcr2 in 2D and 3D (spheroid) cell cultures efficiently transdifferentiated into keratinocyte-like cells (KLCs). An in vivo therapeutic potential of MSCCxcr2 transplantation and its keratinocyte-specific cell fate was observed by accelerated skin tissue regeneration in an excisional splinting wound healing murine model of streptozotocin-induced type 1 diabetes. Finally, 3D skin organoids generated using MSCCxcr2-derived KLCs upon grafting in a relatively avascular and non-healing wounds of type 2 diabetic db/db transgenic old mice resulted in a significant enhancement in the rate of wound closure by increased epithelialization (epidermal layer) and endothelialization (dermal layer). Our findings emphasize the therapeutic role of the CXCL2/CXCR2 axis in inducing trans-differentiation of the MSCs toward KLCs through the activation of ERK1/2 and STAT3 signaling and enhanced skin regeneration potential of 3D organoids grafting in chronic diabetic wounds.

Epidermal growth factor receptor inhibition potentiates chemotherapeutics-mediated sensitization of metastatic breast cancer stem cells

BACKGROUND

Metastasis has been a cause of the poor prognosis and cancer relapse of triple-negative breast cancer (TNBC) patients. The metastatic nature of TNBC is contributed by the breast cancer stem cells (CSCs) which have been implicated in tumorigenesis. Higher expression of epidermal growth factor receptor (EGFR) in breast CSCs has been used as a molecular target for breast cancer therapeutics. Thus, it necessitates the design and generation of efficacious EGFR inhibitors to target the downstream signaling associated with the cellular proliferation and tumorigenesis of breast cancer.

AIM

To generate efficacious EGFR inhibitors that can potentiate the chemotherapeutic-mediated mitigation of breast cancer tumorigenesis.

METHODS AND RESULTS

We identified small molecule EGFR inhibitors using molecular docking studies. In-vitro screening of the compounds was undertaken to identify the cytotoxicity profile of the small-molecule EGFR inhibitors followed by evaluation of the non-cytotoxic compounds in modulating the doxorubicin-induced migration, in-vitro tumorigenesis potential, and their effect on the pro-apoptotic genes' and protein markers' expression in TNBC cells. Compound 1e potentiated the doxorubicin-mediated inhibitory effect on proliferation, migration, in-vitro tumorigenesis capacity, and induction of apoptosis in MDA-MB-231 cells, and in the sorted CD24+-breast cancer cells and CD24-/CD44+-breast CSC populations. Orthotopic xenotransplantation of the breast CSCs-induced tumors in C57BL/6J mice was significantly inhibited by the low dose of Doxorubicin in the presence of compound 1e as depicted by molecular and immunohistochemical analysis.

CONCLUSION

Thus, the study suggests that EGFR inhibition-mediated sensitization of the aggressive and metastatic breast CSCs in TNBCs toward chemotherapeutics may reduce the relapse of the disease.

Therapeutic Potential of Benzimidazoisoquinoline Derivatives in Alleviating Murine Hepatic Fibrosis

Short Title: Benzimidazoisoquinoline derivatives as potent antifibrotics Hepatic fibrosis is a pathological condition of liver disease with an increasing number of cases worldwide. Therapeutic strategies are warranted to target the activated hepatic stellate cells (HSCs), the collagen-producing cells, an effective strategy for controlling the disease progression. Benzimidazoisoquinoline derivatives were synthesized as hybrid molecules by the combination of benzimidazoles and isoquinolines to evaluate their anti-fibrotic potential using an in-vitro and in-vivo model of hepatic fibrosis. A small library of benzimidazoisoquinoline derivatives (1-17 and 18-21) was synthesized from 2-aryl benzimidazole and acetylene functionalities through C-H and N-H activation. Compounds (10 and its recently synthesized derivatives 18-21) depicted a significant decrease in PDGF-BB and/or TGFβ-induced proliferation (1.7-1.9 -fold), migration (3.5-5.0 -fold), and fibrosis-related gene expressions in HSCs. These compounds could revert the hepatic damage caused by chronic exposure to hepatotoxicants, ethanol, and/or carbon tetrachloride as evident from the histological, biochemical, and molecular analysis. Anti-fibrotic effect of the compounds was supported by the decrease in the malondialdehyde level, collagen deposition, and gene expression levels of fibrosis-related markers such as α-SMA, COL1α1, PDGFRβ, and TGFRIIβ in the preclinical models of hepatic fibrosis. In conclusion, the synthesized benzimidazoisoquinoline derivatives (compounds 18, 19, 20, and 21) possess anti-fibrotic therapeutic potential against liver fibrosis.

Malate-Based Biodegradable Scaffolds Activate Cellular Energetic Metabolism for Accelerated Wound Healing

The latest advancements in cellular bioenergetics have revealed the potential of transferring chemical energy to biological energy for therapeutic applications. Despite efforts, a three-dimensional (3D) scaffold that can induce long-term bioenergetic effects and facilitate tissue regeneration remains a big challenge. Herein, the cellular energetic metabolism promotion ability of l-malate, an important intermediate of the tricarboxylic acid (TCA) cycle, was proved, and a series of bioenergetic porous scaffolds were fabricated by synthesizing poly(diol l-malate) (PDoM) prepolymers via a facial one-pot polycondensation of l-malic acid and aliphatic diols, followed by scaffold fabrication and thermal-cross-linking. The degradation products of the developed PDoM scaffolds can regulate the metabolic microenvironment by entering mitochondria and participating in the TCA cycle to elevate intracellular adenosine triphosphate (ATP) levels, thus promoting the cellular biosynthesis, including the production of collagen type I (Col1a1), fibronectin 1 (Fn1), and actin alpha 2 (Acta2/α-Sma). The porous PDoM scaffold was demonstrated to support the growth of the cocultured mesenchymal stem cells (MSCs) and promote their secretion of bioactive molecules [such as vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and basic fibroblast growth factor (bFGF)], and this stem cells-laden scaffold architecture was proved to accelerate wound healing in a critical full-thickness skin defect model on rats.

ZEB1 potentiates chemoresistance in breast cancer stem cells by evading apoptosis

Chemoresistance renders a challenge to the clinics to treat breast cancer patients. Current treatment strategies are effective in mitigating tumor growth but remain largely ineffective against cancer-initiating cells or breast Cancer Stem Cells (CSCs). Epithelial-to-mesenchymal-transition (EMT) regulates breast CSC physiology. Zinc finger E-box binding homeobox 1 (ZEB1) is a key EMT-transcription factor that regulates breast CSC - differentiation and metastasis. However, its potential role in modulating tumor chemoresistance has not yet been fully understood. In-silico analysis revealed a higher ZEB1 expression in breast cancer patients that leads to decreased overall and relapse-free survival. We generated sorted breast CSC with stable ZEB1 overexpression (CD24-/CD44+GFP-ZEB1) and/or silencing (CD24-/CD44+ZEB1 shRNA) as well as breast cancer cells with stable ZEB1 overexpression (CD24+GFP-ZEB1) and/or silencing (CD24+ZEB1 shRNA). An increased colony-forming efficiency and doxorubicin accumulation correlated with decreased promoter activity and expression profile of ABCC1 drug-efflux ABC transporter in CD24-/CD44+GFP-ZEB1. Additionally, CD24-/CD44+GFP-ZEB1 demonstrated doxorubicin-induced higher anti-apoptotic and lower pro-apoptotic protein expressions in the mitochondrial and cytosolic fractions. Chemoresistant CD24-/CD44+GFP-ZEB1 cells depicted 1000-fold higher IC-50 values of doxorubicin and decreased activation of JNK-p38 stress kinase molecular signaling-dependent mammosphere forming efficiency to evade apoptosis. Thus, ZEB1 and its downstream effectors are plausible therapeutic targets for the mitigation of breast cancer chemoresistance in patients.

Three-Dimensional Scaffolds for Bone Tissue Engineering

Immobilization using external or internal splints is a standard and effective procedure to treat minor skeletal fractures. In the case of major skeletal defects caused by extreme trauma, infectious diseases or tumors, the surgical implantation of a bone graft from external sources is required for a complete cure. Practical disadvantages, such as the risk of immune rejection and infection at the implant site, are high in xenografts and allografts. Currently, an autograft from the iliac crest of a patient is considered the "gold standard" method for treating large-scale skeletal defects. However, this method is not an ideal solution due to its limited availability and significant reports of morbidity in the harvest site (30%) as well as the implanted site (5-35%). Tissue-engineered bone grafts aim to create a mechanically strong, biologically viable and degradable bone graft by combining a three-dimensional porous scaffold with osteoblast or progenitor cells. The materials used for such tissue-engineered bone grafts can be broadly divided into ceramic materials (calcium phosphates) and biocompatible/bioactive synthetic polymers. This review summarizes the types of materials used to make scaffolds for cryo-preservable tissue-engineered bone grafts as well as the distinct methods adopted to create the scaffolds, including traditional scaffold fabrication methods (solvent-casting, gas-foaming, electrospinning, thermally induced phase separation) and more recent fabrication methods (fused deposition molding, stereolithography, selective laser sintering, Inkjet 3D printing, laser-assisted bioprinting and 3D bioprinting). This is followed by a short summation of the current osteochondrogenic models along with the required scaffold mechanical properties for in vivo applications. We then present a few results of the effects of freezing and thawing on the structural and mechanical integrity of PLLA scaffolds prepared by the thermally induced phase separation method and conclude this review article by summarizing the current regulatory requirements for tissue-engineered products.

Collagen scaffolds derived from bovine skin loaded with MSC optimized M1 macrophages remodeling and chronic diabetic wounds healing

Owing to the persistent inflammatory microenvironment and unsubstantial dermal tissues, chronic diabetic wounds do not heal easily and their recurrence rate is high. Therefore, a dermal substitute that can induce rapid tissue regeneration and inhibit scar formation is urgently required to address this concern. In this study, we established biologically active dermal substitutes (BADS) by combining novel animal tissue-derived collagen dermal-replacement scaffolds (CDRS) and bone marrow mesenchymal stem cells (BMSCs) for the healing and recurrence treatments of chronic diabetic wounds. The collagen scaffolds derived from bovine skin (CBS) displayed good physicochemical properties and superior biocompatibility. CBS loaded with BMSCs (CBS-MCSs) could inhibit M1 macrophage polarization in vitro. Decreased MMP-9 and increased Col3 at the protein level were detected in CBS-MSCs-treated M1 macrophages, which may be attributed to the suppression of the TNF-α/NF-κB signaling pathway (downregulating phospho-IKKα/β/total IKKα/β, phospho-IκB/total IκB, and phospho-NFκB/total NFκB) in M1 macrophages. Moreover, CBS-MSCs could benefit the transformation of M1 (downregulating iNOS) to M2 (upregulating CD206) macrophages. Wound-healing evaluations demonstrated that CBS-MSCs regulated the polarization of macrophages and the balance of inflammatory factors (pro-inflammatory: IL-1β, TNF-α, and MMP-9; anti-inflammatory: IL-10 and TGF-β3) in db/db mice. Furthermore, CBS-MSCs facilitated the noncontractile and re-epithelialized processes, granulation tissue regeneration, and neovascularization of chronic diabetic wounds. Thus, CBS-MSCs have a potential value for clinical application in promoting the healing of chronic diabetic wounds and preventing the recurrence of ulcers.

Denuded Descemet's membrane supports human embryonic stem cell-derived retinal pigment epithelial cell culture

Recent clinical studies suggest that retinal pigment epithelial (RPE) cell replacement therapy may preserve vision in retinal degenerative diseases. Scaffold-based methods are being tested in ongoing clinical trials for delivering pluripotent-derived RPE cells to the back of the eye. The aim of this study was to investigate human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells survival and behaviour on a decellularized Descemet's Membrane (DM), which may be of clinical relevance in retinal transplantation. DMs were isolated from human donor corneas and treated with thermolysin. The DM surface topology and the efficiency of the denudation method were evaluated by atomic force microscope, scanning electron microscopy and histology. hESC-RPE cells were seeded onto the endothelial-side surface of decellularized DM in order to determine the potential of the membrane to support hESC-RPE cell culture, alongside maintaining their viability. Integrity of the hESC-RPE monolayer was assessed by measuring transepithelial resistance. RPE-specific gene expression and growth factors secretion were assessed to confirm maturation and functionality of the cells over the new substrate. Thermolysin treatment did not affect the integrity of the tissue, thus ensuring a reliable method to standardize the preparation of decellularized DM. 24 hours post-seeding, hESC-RPE cell attachment and initial proliferation rate over the denuded DM were higher than hESC-RPE cells cultured on tissue culture inserts. On the new matrix, hESC-RPE cells succeeded in forming an intact monolayer with mature tight junctions. The resulting cell culture showed characteristic RPE cell morphology and proper protein localization. Gene expression analysis and VEGF secretion demonstrate DM provides supportive scaffolding and inductive properties to enhance hESC-RPE cells maturation. Decellularized DM was shown to be capable of sustaining hESC-RPE cells culture, thus confirming to be potentially a suitable candidate for retinal cell therapy.

Current Progress and Outlook of Nano-Based Hydrogel Dressings for Wound Healing

Wound dressing is an important tool for wound management. Designing wound dressings by combining various novel materials and drugs to optimize the peri-wound environment and promote wound healing is a novel concept. Hydrogels feature good ductility, high water content, and favorable oxygen transport, which makes them become some of the most promising materials for wound dressings. In addition, nanomaterials exhibit superior biodegradability, biocompatibility, and colloidal stability in wound healing and can play a role in promoting healing through their nanoscale properties or as carriers of other drugs. By combining the advantages of both technologies, several outstanding and efficient wound dressings have been developed. In this paper, we classify nano-based hydrogel dressings into four categories: hydrogel dressings loaded with a nanoantibacterial drug; hydrogel dressings loaded with oxygen-delivering nanomedicines; hydrogel dressings loaded with nanonucleic acid drugs; and hydrogel dressings loaded with other nanodelivered drugs. The design ideas, advantages, and challenges of these nano-based hydrogel wound dressings are reviewed and analyzed. Finally, we envisaged possible future directions for wound dressings in the context of relevant scientific and technological advances, which we hope will inform further research in wound management.

Lipozyme® TL IM Biocatalyst for Castor Oil FAME and Triacetin Production by Interesterification: Activity, Stability, and Kinetics

Global climate change and present geopolitical tensions call for novel, renewable, and, ideally, sustainable resources and processes that, in the end, will be integrated in the natural cycles of carbon and water, progressively replacing non-renewable feedstocks. In this context, the production of biofuels and, in consequence, of biodiesel plays a notable role. This work is focused on the production of fatty acid methyl esters (FAME) from castor oil, an abundant non-edible oil, using a sustainable technology approach based on industrial lipases and methyl acetate as a methylating reagent to reduce biocatalyst inactivation. We have selected a stable industrial enzyme preparation to determine its suitability for FAME production: Lipozyme® TL IM (an inexpensive lipase from Thermomyces lanuginosus immobilized by agglomeration in silica gel). Several operational variables affecting the enzyme activity have been studied: methanol excess (6:1 to 13:1), temperature (from 40 to 60 °C), and enzyme concentration (10 and 30% w/w). At all temperatures and reagent ratios, we have also tested the enzyme stability for six cycles, showing its low to negligible inactivation under operational conditions. Finally, a novel multivariable kinetic model has been proposed and fitted to experimental data obtained in a wide experimental range for the first time, showing that direct and reverse in-series reactions are present. We have estimated the values of the kinetic constants and their standard errors, and goodness-of-fit parameters, observing that the kinetic model fitted very reasonably to all retrieved experimental data at the same time.

Smart biomaterials and their potential applications in tissue engineering

Smart biomaterials have been rapidly advancing ever since the concept of tissue engineering was proposed. Interacting with human cells, smart biomaterials can play a key role in novel tissue morphogenesis. Various aspects of biomaterials utilized in or being sought for the goal of encouraging bone regeneration, skin graft engineering, and nerve conduits are discussed in this review. Beginning with bone, this study summarizes all the available bioceramics and materials along with their properties used singly or in conjunction with each other to create scaffolds for bone tissue engineering. A quick overview of the skin-based nanocomposite biomaterials possessing antibacterial properties for wound healing is outlined along with skin regeneration therapies using infrared radiation, electrospinning, and piezoelectricity, which aid in wound healing. Furthermore, a brief overview of bioengineered artificial skin grafts made of various natural and synthetic polymers has been presented. Finally, by examining the interactions between natural and synthetic-based biomaterials and the biological environment, their strengths and drawbacks for constructing peripheral nerve conduits are highlighted. The description of the preclinical outcome of nerve regeneration in injury healed with various natural-based conduits receives special attention. The organic and synthetic worlds collide at the interface of nanomaterials and biological systems, producing a new scientific field including nanomaterial design for tissue engineering.

Bioinspired All-in-One Three-Dimensional Dynamic CellMatrix Improves the Manufacture of Therapeutically Qualified Cells for Cell Therapy

Despite the great promise, cell therapy still faces practical challenges because of the scarcity of a reliable cell source. Herein, a bioinspired 3D dynamic culture system (CellMatrix) with rational structure, composite and function, was developed for improving cell supply. CellMatrix was composed of unique core-shell fibers with a core of black phosphorus-incorporated fibroin and a shell of sericin, which together formed a 3D silkworm cocoon-mimicking structure via a bottom-up fabrication technique. CellMatrix not only provided optimal engineered biomimetic niche to facilitate cell growth but exhibited good photothermal conversion to dynamically regulate cell fates. Importantly, cell-CellMatrix construct could be directly implanted into defected tissues and improved tissue remodeling. Meanwhile, CellMatrix displayed good ice resistance and thermal conductivity, which maximally maintained cell viability and proliferation after the freeze-thawing process, allowing for storing precious cells and cell-CellMatrix construct. Thus, CellMatrix represents an all-in-one biomimetic platform for the culture-production-storage of therapeutically qualified cells.

Cell-based dressings: A journey through chronic wound management

The field of regenerative medicine has undergone a paradigm shift in recent decades thanks to the emergence of novel therapies based on the use of living organisms. The development of cell-based strategies has become a trend for the treatment of different conditions and pathologies. In this sense, the need for more adequate, biomimetic and well-planned treatments for chronic wounds has found different and innovative strategies, based on the combination of cells with dressings, which seek to revolutionize the wound healing management. Therefore, the objective of this review is to analyze the current state and the latest advances in the research of cell-based dressings for chronic wounds, ranging from traditional and "second generation" bioengineered living skin equivalents to mesenchymal stem cell dressings; the latter include biopolymeric porous scaffolds, electrospun nanofiber meshes, hydrogels and 3D printed bio-printed dressings. Finally, this review updates the completed and ongoing clinical trials in this field and encourages researchers to rethink these new approaches, manufacturing processes and mechanisms of action, as well as their administration strategies and timings.

Nanoengineered therapeutic scaffolds for burn wound management

BACKGROUND

Wound healing is a complex process, and selecting an appropriate treatment is crucial and varies from one wound to another. Among injuries, burn wounds are more challenging to treat. Different dressings and scaffolds come into play when skin is injured. These scaffolds provide the optimum environment for wound healing. With the advancements of nanoengineering, scaffolds have been engineered to improve wound healing with lower fatality rates.

OBJECTIVES

Nanoengineered systems have emerged as one of the promising candidates for burn wound management. This review paper aims to provide an in-depth understanding of burn wounds and the role of nanoengineering in burn wound management. The advantages of nanoengineered scaffolds, their properties, and their proven effectiveness have been discussed. Nanoparticles and nanofibers-based nanoengineered therapeutic scaffolds provide optimum protection, infection management, and accelerated wound healing due to their unique characteristics. These scaffolds increase cell attachment and proliferation for desired results.

RESULTS

The literature review suggested that the utilization of nanoengineered scaffolds has accelerated burn wound healing. Nanofibers provide better cell attachment and proliferation among different nanoengineered scaffolds due to their 3D structure mimics the body's extracellular matrix.

CONCLUSION

With the application of these advanced nanoengineered scaffolds, better burn wound management is possible due to sustained drug delivery, better cell attachment, and an infection-free environment.

The remarkable effect of menstrual blood stem cells seeded on bilayer scaffold composed of amniotic membrane and silk fibroin aiming to promote wound healing in diabetic mice

INTRODUCTION

Impaired chronic wound healing frequently occurs in diabetic patients. We hypothesized that menstrual blood-derived mesenchymal stem cells (MenSCs) in combination with bilayer scaffold consisted of human amniotic membrane (AM) and electrospun silk fibroin nanofibers could potentially promote wound healing in diabetic mice.

METHODS & METHODS

Two bilateral full-thickness wounds were created on dorsal skin of type-1 diabetic mice model and animals were equally divided in four groups including: no-treatment group (NT), amniotic membrane treated group (AM), bilayer scaffold treated group (bSC), and MenSCs-seeded bilayer scaffold treated group (bSC + MenSCs). Wound healing evaluations were performed at 3, 7, and 14 days after their treatment. The wound healing was analyzed by macroscopic and microscopic evaluations, and immunofluorescence staining of involucrin (IVL), type III collagen, CD31/ von Willebrand factor (vWF), and PGP9.5 were performed. Furthermore, number of neutrophils and macrophages and subpopulation of macrophages were assessed. In addition, the expression of Egr2, Mmp9, CXCL12, IDO1, Ptgs2 and VEGFA transcripts involved in wound repair were also analyzed.

RESULTS

After 14 days, the best epidermal and dermal regeneration belonged to the cases received bSC + MenSCs as wound dressing. Moreover, the wound healing was typically faster in this group compared to other groups. Immunofluorescence evaluation represented higher levels of CD31 and VWF, higher ratio of M2/M1 macrophages, greater expression of IVL, and higher levels of the PGP9.5 in the bSC + MenSCs group in comparison with other groups. Expression analysis of assessed genes also supported assumption of more regeneration and healing in the bSC + MenSCs group versus other groups.

CONCLUSION

These results indicate that enhanced immunomodulatory and reparative properties of MenSCs in conjunction with bilayer scaffold specified this cellular skin substitute for modulating wound chronicity and contribution to resolution of wound healing process in diabetic ulcer.

Conductive, Self-Healing, Adhesive, and Antibacterial Hydrogels Based on Lignin/Cellulose for Rapid MRSA-Infected Wound Repairing

The abuse of antibiotics induces the emergence of drug-resistant bacteria, which greatly increases the difficulty of clinical treatment of infected wounds. It is urgent to design a multifunctional wound dressing independent of antibiotics. In this work, we designed multifunctional hydrogels based on lignin and cellulose in natural polymers. Lignin with antioxidant properties could reduce silver nanoparticles in situ and could also be used as a crosslinking agent to construct hydrogels between hydroxypropyl cellulose modified with phenylboric acid by a dynamic borate bond. Hydrogels have excellent properties such as self-healing, shape adaptability, biocompatibility, blood compatibility, antioxidant properties, excellent broad-spectrum antimicrobial properties, good tissue adhesion, and electrical conductivity. The tissue adhesion of hydrogels endows them with an excellent hemostasis property in a rat liver injury model. In vivo experiments demonstrated that hydrogels can maintain a moist healing environment, reduce inflammatory cell infiltration, promote M2 macrophage polarization, accelerate collagen deposition, promote the regeneration of new blood vessels, and significantly speed up the wound healing of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds. Therefore, these multifunctional hydrogels are an excellent candidate to treat multiple stages of wound healing and have a broad application prospect in the medical field.

Porous polymeric membranes: fabrication techniques and biomedical applications

Porous polymeric membranes have shown great potential in biological and biomedical applications such as tissue engineering, bioseparation, and biosensing, due to their structural flexibility, versatile surface chemistry, and biocompatibility. This review outlines the advantages and limitations of the fabrication techniques commonly used to produce porous polymeric membranes, with especial focus on those featuring nano/submicron scale pores, which include track etching, nanoimprinting, block-copolymer self-assembly, and electrospinning. Recent advances in membrane technology have been key to facilitate precise control of pore size, shape, density and surface properties. The review provides a critical overview of the main biological and biomedical applications of these porous polymeric membranes, especially focusing on drug delivery, tissue engineering, biosensing, and bioseparation. The effect of the membrane material and pore morphology on the role of the membranes for each specific application as well as the specific fabrication challenges, and future prospects of these membranes are thoroughly discussed.

Anti-inflammation biomaterial platforms for chronic wound healing

Nowadays, there has been an increase in the number of people with chronic wounds, which has resulted in serious health problems worldwide. The rate-limiting stage of chronic wound healing has been found to be the inflammation stage, and strategies for shortening the prolonged inflammatory response have proven to be effective for increasing the healing rate. Recently, various anti-inflammatory strategies (such as anti-inflammatory drugs, antioxidant, NO regulation, antibacterial, immune regulation and angiogenesis) have attracted attention as potential therapeutic pathways. Moreover, various biomaterial platforms based on anti-inflammation therapy strategies have also emerged in the spotlight as potential therapies to accelerate the repair of chronic wounds. In this review, we systematically investigated the advances of various biomaterial platforms based on anti-inflammation strategies for chronic wound healing, to provide valuable guidance for future breakthroughs in chronic wound treatment.

Macrophage Related Chronic Inflammation in Non-Healing Wounds

Persistent hyper-inflammation is a distinguishing pathophysiological characteristic of chronic wounds, and macrophage malfunction is considered as a major contributor thereof. In this review, we describe the origin and heterogeneity of macrophages during wound healing, and compare macrophage function in healing and non-healing wounds. We consider extrinsic and intrinsic factors driving wound macrophage dysregulation, and review systemic and topical therapeutic approaches for the restoration of macrophage response. Multidimensional analysis is highlighted through the integration of various high-throughput technologies, used to assess the diversity and activation states as well as cellular communication of macrophages in healing and non-healing wound. This research fills the gaps in current literature and provides the promising therapeutic interventions for chronic wounds.

Tailoring the growth and proliferation of human dermal fibroblasts by DNA-based polymer films for skin regeneration

The use of DNA as a functional biomaterial for therapeutic, diagnostic, and drug delivery applications has been prominent in recent years, but its use as a scaffold for tissue regeneration is still limited. This study aimed to evaluate the biocompatibility and interaction of DNA-based polymeric films (DNA-PFs) with primary human fibroblasts (PHF) for regenerative medicine and wound healing purposes. The morphological characterization of the films was performed by scanning electron microscopy, SEM-energy-dispersive X-ray spectroscopy, and atomic force microscopy analysis. Cell viability, cell cycle kinetics, oxidative stress, and migration studies were carried out at 48 and 72 hr of incubation and compared to control cells. Cell adhesion was impaired in the first 24 hr, DNA-PFs with higher concentrations of DNA (1.0 and 2.0 g/L) this effect was not seen in DNA-PFs (0.5 g/L), explained by the difference in topography and roughness of DNA-PFs, but it was overcome after 48 hr of incubation. PHF seeded on DNA films showed higher proliferation and migration rates than the control after 48 hr of incubation, with the maintenance of cell morphology and lower cytotoxicity and oxidative stress during the evaluation time. Therefore, these results indicate that DNA-PFs are highly biocompatible and provide a suitable microenvironment for dermal fibroblasts to maintain their activity, helping build new and more complex biomaterials suitable for future tissue repair applications.

Magnetically-driven drug and cell on demand release system using 3D printed alginate based hollow fiber scaffolds

Local delivery of drugs, proteins and living cells with on demand release manner using porous scaffolds has been widely used in the field of tissue engineering and cancer therapies. Drugs directly loaded in the porous scaffolds, are generally prone to free diffuse especially for long term incubation. Herein, in this study, hollow fiber alginate/iron oxide nanoparticles scaffolds were prepared by coaxial 3D printing with drugs, protein or living cells encapsulating in the core part (low concentration of alginate gels). Magnetically-driven on demand release was realized by extruding the loaded drugs, proteins and cells from the core part of the hollow fibers due to the deformation of the scaffolds under magnetic field. Additionally, the hollow fibers could sever as diffusion barriers to reduce uncontrolled diffusion of drugs, proteins and cells from scaffolds in the conditions of no required stimulation. The factors influencing the deformation of the scaffolds, as well as the release behavior were investigated. The data indicated that the scaffolds prepared by 10 wt% of alginate with 13% of iron oxide nanoparticles after crosslinking using 0.1 M CaCl₂ solution for 10 s showed repeated on demand release capability in vitro and in vivo under intermittently magnetic stimulation. Thus, this 3D printed alginate/iron oxide nanoparticles hollow scaffolds with on demand controlled delivery capability may prove useful for tissue engineering and disease therapies.

Advances in generation of three-dimensional skin equivalents: pre-clinical studies to clinical therapies

The inability of two-dimensional cell culture systems to adequately map the structure and function of complex organs like skin necessitates the development of three-dimensional (3D) skin models. A diverse range of 3D skin equivalents have been developed over the last few decades for studying complex properties of skin as well as for drug discovery and clinical applications for skin regeneration in chronic wounds, such as diabetic foot ulcers, where the normal mechanism of wound healing is compromised. These 3D skin substitutes also serve as a suitable alternative to animal models in industrial applications and fundamental research. With the emergence of tissue engineering, new scaffolds and matrices have been integrated into 3D cell culture systems, along with gene therapy approaches, to increase the efficacy of transplanted cells in skin regeneration. This review summarizes recent approaches to the development of skin equivalents as well as different models for studying skin diseases and properties and current therapeutic applications of skin substitutes.

TWIST1-Reprogrammed Endothelial Cell Transplantation Potentiates Neovascularization-Mediated Diabetic Wound Tissue Regeneration

Hypovascularized diabetic nonhealing wounds are due to reduced number and impaired physiology of endogenous endothelial progenitor cell (EPC) population that limits their recruitment and mobilization at the wound site. For enrichment of the EPC repertoire from nonendothelial precursors, abundantly available mesenchymal stromal cells (MSC) were reprogrammed into induced endothelial cells (iEC). We identified cell signaling molecular targets by meta-analysis of microarray data sets. BMP-2 induction leads to the expression of inhibitory Smad 6/7-dependent negative transcriptional regulation of ID1, rendering the latter's reduced binding to TWIST1 during transdifferentiation of Wharton jelly-derived MSC (WJ-MSC) into iEC. TWIST1, in turn, regulates endothelial gene transcription, positively of proangiogenic KDR and negatively, in part, of antiangiogenic SFRP4 Twist1 reprogramming enhanced the endothelial lineage commitment of WJ-MSC and increased the vasculogenic potential of reprogrammed endothelial cells (rEC). Transplantation of stable TWIST1 rEC into a type 1 and 2 diabetic full-thickness splinted wound healing murine model enhanced the microcirculatory blood flow and accelerated the wound tissue regeneration. An increased or decreased colocalization of GFP with KDR/SFRP4 and CD31 in the regenerated diabetic wound bed with TWIST1 overexpression or silencing (piLenti-TWIST1-shRNA-GFP), respectively, further confirmed improved neovascularization. This study depicted the reprogramming of WJ-MSC into rEC using unique transcription factor TWIST1 for an efficacious cell transplantation therapy to induce neovascularization-mediated diabetic wound tissue regeneration.

Epidermal growth factor in sacran hydrogel film accelerates fibroblast migration

Epidermal growth factor (EGF) accelerates epidermal regeneration, and it is widely studied as a wound-healing agent. However, the special carrier for the topical administration of EGF is urgently needed to deliver EGF on the wound site. In a preceding study, sacran hydrogel film (Sac-HF) showed a possible use as a dressing material for wound healing, as well as a good capability as a drug carrier. In the current study, we prepared Sac-HF containing EGF (Sac/EGF-HF) and then characterized their physicochemical properties, including thickness, swelling ratio, degradability, tensile strength, and morphology. In addition, we have also conducted thermal and crystallography studies using differential scanning calorimetry (DSC) and X-ray diffraction, respectively. Furthermore, we investigated the in vitro influence of Sac/EGF-HF on cell migration using a fibroblast cell line. Morphology study confirmed that the casting method used for the film preparation resulted in a homogeneous film of Sac/EGF-HF. Furthermore, EGF significantly increased the thickness, tensile strength, and degradability of Sac/EGF-HF compared to Sac-HF. Sac/EGF-HF had a lower swelling ability compared to Sac-HF; this result corroborated the tensile strength result. Interestingly, X-ray diffraction and DSC results showed that Sac/EGF-HF had an amorphous shape. The in vitro studies revealed that Sac/EGF-HF induced the fibroblast migration activity. These results conclude that Sac/EGF-HF has the potential properties of HF for biomedical applications.

The therapeutic impact of human neonatal BMSC in a right ventricular pressure overload model in mice

Objective

To determine the impact of donor age on the therapeutic effect of bone marrow-derived mesenchymal stem cells (BMSCs) in treating adverse remodeling as the result of right ventricle (RV) pressure overload.

Methods

BMSCs were isolated from neonatal (< 1 month), infant (1 month to 1 year), and young children (1 year to 5 years) and were compared in their migration potential, surface marker expression, VEGF secretion, and matrix metalloprotein (MMP) 9 expression. Four-week-old male C57 mice underwent pulmonary artery banding and randomized to treatment and untreated control groups. During the surgery, BMSCs were administered to the mice by intramyocardial injection into the RV free wall. Four weeks later, RV function and tissue were analyzed by echocardiography, histology, and quantitative real-time polymerase chain reaction.

Results

Human neonatal BMSCs demonstrated the greatest migration capacity and secretion of vascular endothelial growth factor but no difference in expression of surface markers. Neonate BMSCs administration resulted in increasing expression of VEGF, a significant reduction in RV wall thickness, and internal diameter in mice after PA banding. These beneficial effects were probably associated with paracrine secretion as no cardiomyocyte transdifferentiation was observed.

Conclusions

Human BMSCs from different age groups have different characteristics, and the youngest BMSCs may favorably impact the application of stem cell-based therapy to alleviate adverse RV remodeling induced by pressure overload.

Cxcr6-Based Mesenchymal Stem Cell Gene Therapy Potentiates Skin Regeneration in Murine Diabetic Wounds

Mesenchymal stem cell (MSC) therapies for wound healing are often compromised due to low recruitment and engraftment of transplanted cells, as well as delayed differentiation into cell lineages for skin regeneration. An increased expression of chemokine ligand CXCL16 in wound bed and its cognate receptor, CXCR6, on murine bone-marrow-derived MSCs suggested a putative therapeutic relevance of exogenous MSC transplantation therapy. Induction of the CXCL16-CXCR6 axis led to activation of focal adhesion kinase (FAK), Src, and extracellular signal-regulated kinases 1/2 (ERK1/2)-mediated matrix metalloproteinases (MMP)-2 promoter regulation and expression, the migratory signaling pathways in MSC. CXCL16 induction also increased the transdifferentiation of MSCs into endothelial-like cells and keratinocytes. Intravenous transplantation of allogenic stable MSCs with Cxcr6 gene therapy potentiated skin tissue regeneration by increasing recruitment and engraftment as well as neovascularization and re-epithelialization at the wound site in excisional splinting wounds of type I and II diabetic mice. This study suggests that activation of the CXCL16-CXCR6 axis in bioengineered MSCs with Cxcr6 overexpression provides a promising therapeutic approach for the treatment of diabetic wounds.

Biomaterials for bone tissue engineering scaffolds: a review

Bone tissue engineering has been continuously developing since the concept of "tissue engineering" has been proposed. Biomaterials that are used as the basic material for the fabrication of scaffolds play a vital role in bone tissue engineering. This paper first introduces a strategy for literature search. Then, it describes the structure, mechanical properties and materials of natural bone and the strategies of bone tissue engineering. Particularly, it focuses on the current knowledge about biomaterials used in the fabrication of bone tissue engineering scaffolds, which includes the history, types, properties and applications of biomaterials. The effects of additives such as signaling molecules, stem cells, and functional materials on the performance of the scaffolds are also discussed.

H₂O₂ Damages the Stemness of Rat Bone Marrow-Derived Mesenchymal Stem Cells: Developing a "Stemness Loss" Model

Background

The number of patients with spinal cord injury caused by motor vehicle accidents, violent injuries, and other types of trauma increases year by year, and bone marrow mesenchymal stem cell (BMSC) transplants are being widely investigated to treat this condition. However, the success rate of BMSCs transplants is relatively low due to the presence of oxidative stress in the new microenvironment. Our main goals in the present study were to evaluate the damaging effects of H₂O₂ on BMSCs and to develop a model of “stemness loss” using rat BMSCs.

Material/Methods

Bone marrow-derived mesenchymal stem cells were obtained from the bone marrow of young rats reared under sterile conditions. The stem cells were used after 2 passages following phenotypic identification. BMSCs were divided into 4 groups to evaluate the damaging effects of H₂O₂: A. blank control; B. 100 uM H₂O₂; C. 200 uM H₂O₂ and D. 300 uM H₂O₂. The ability of the BMSCs to differentiate into 3 cell lineages and their colony formation and migration capacities were analyzed by gene expression, colony formation, and scratch assays.

Results

The cells we obtained complied with international stem cell standards demonstrated by their ability to differentiate into 3 cell lineages. We found that 200–300 uM H₂O₂ had a significant effect on the biological behavior of BMSCs, including their ability to differentiate into 3 cell lineages, the expression of stemness-related proteins, and their migration and colony formation capacities.

Conclusions

H₂O₂ can damage the stemness ability of BMSCs at a concentration of 200–300 uM.

New strategy of bone marrow mesenchymal stem cells against oxidative stress injury via Nrf2 pathway: oxidative stress preconditioning

Clinically, bone marrow mesenchymal stem cells (BMSCs) have been used in treatment of many diseases, but the local oxidative stress (OS) of lesion severely limits the survival of BMSCs, which reduces the efficacy of BMSCs transplantation. Therefore, enhancing the anti‐OS stress ability of BMSCs is a key breakthrough point. Preconditioning is a common protective mechanism for cells or body. Here, the aim of this study was to investigate the effects of OS preconditioning on the anti‐OS ability of BMSCs and its mechanism. Fortunately, OS preconditioning can increase the expression of superoxide dismutase, catalase, NQO1, and heme oxygenase 1 through the nuclear factor erythroid 2‐related factor 2 pathway, thereby decreased the intracellular reactive oxygen species (ROS) levels, relieved the damage of ROS to mitochondria, DNA and cell membrane, enhanced the anti‐OS ability of BMSCs, and promoted the survival of BMSCs under OS.

Nano-drug delivery systems in wound treatment and skin regeneration

Skin damages are defined as one of most common lesions people suffer from, some of wounds are notoriously difficult to eradicate such as chronic wounds and deep burns. Existing wound therapies have been proved to be inadequate and far from satisfactory. The cutting-edge nanotechnology offers an unprecedented opportunity to revolutionize and invent new therapies or boost the effectiveness of current medical treatments. In particular, the nano-drug delivery systems anchor bioactive molecules to applied area, sustain the drug release and explicitly enhance the therapeutic efficacies of drugs, thus making a fine figure in field relevant to skin regeneration. This review summarized and discussed the current nano-drug delivery systems holding pivotal potential for wound healing and skin regeneration, with a special emphasis on liposomes, polymeric nanoparticles, inorganic nanoparticles, lipid nanoparticles, nanofibrous structures and nanohydrogel.

Regeneration and Repair of Skin Wounds: Various Strategies for Treatment

Skin as a mechanical barrier between the inner and outer environment of our body protects us against infection and electrolyte loss. This organ consists of 3 layers: the epidermis, dermis, and hypodermis. Any disruption in the integrity of skin leads to the formation of wounds, which are divided into 2 main categories: acute wounds and chronic wounds. Generally, acute wounds heal relatively faster. In contrast to acute wounds, closure of chronic wounds is delayed by 3 months after the initial insult. Treatment of chronic wounds has been one of the most challenging issues in the field of regenerative medicine, promoting scientists to develop various therapeutic strategies for a fast, qualified, and most cost-effective treatment modality. Here, we reviewed more recent approaches, including the development of stem cell therapy, tissue-engineered skin substitutes, and skin equivalents, for the healing of complex wounds.

Therapeutic strategies for enhancing angiogenesis in wound healing

The enhancement of wound healing has been a goal of medical practitioners for thousands of years. The development of chronic, non-healing wounds is a persistent medical problem that drives patient morbidity and increases healthcare costs. A key aspect of many non-healing wounds is the reduced presence of vessel growth through the process of angiogenesis. This review surveys the creation of new treatments for healing cutaneous wounds through therapeutic angiogenesis. In particular, we discuss the challenges and advancement that have been made in delivering biologic, pharmaceutical and cell-based therapies as enhancers of wound vascularity and healing.

Porous Se@SiO2 nanosphere-coated catheter accelerates prostatic urethra wound healing by modulating macrophage polarization through reactive oxygen species-NF-κB pathway inhibition

Benign prostatic hyperplasia (BPH) patients experience complications after surgery. We studied oxidative stress scavenging by porous Se@SiO₂ nanospheres in prostatic urethra wound healing after transurethral resection of the prostate (TURP). Beagle dogs were randomly distributed into two groups after establishing TURP models. Wound recovery and oxidative stress levels were evaluated. Re-epithelialization and the macrophage distribution at the wound site were assessed by histology. The mechanism by which porous Se@SiO₂ nanospheres regulated macrophage polarization was investigated by qRT-PCR, western blotting, flow cytometry, immunofluorescence and dual luciferase reporter gene assays. Our results demonstrated that Porous Se@SiO₂ nanosphere-coated catheters advance re-epithelization of the prostatic urethra, accelerating wound healing in beagle dogs after TURP, and improve the antioxidant capacity to inhibit oxidative stress and induced an M2 phenotype transition of macrophages at the wound. By restraining the function of reactive oxygen species (ROS), porous Se@SiO₂ nanospheres downregulated Ikk, IκB and p65 phosphorylation to block the downstream NF-κB pathway in macrophages in vitro. Since activation of NF-κB signaling cascades drives macrophage polarization, porous Se@SiO₂ nanospheres promoted macrophage phenotype conversion from M1 to M2. Our findings suggest that porous Se@SiO₂ nanosphere-coated catheters promote postoperative wound recovery in the prostatic urethra by promoting macrophage polarization toward the M2 phenotype through suppression of the ROS-NF-κB pathway, attenuating the inflammatory response. STATEMENT OF SIGNIFICANCE: The inability to effectively control post-operative inflammatory responses after surgical treatment of benign prostatic hyperplasia (BPH) remains a challenge to researchers and surgeons, as it can lead to indirect cell death and ultimately delay wound healing. Macrophages at the wound site work as pivotal regulators of local inflammatory response. Here, we designed and produced a new type of catheter with a coating of porous Se@SiO₂ nanosphere and demonstrated its role in promoting prostatic urethra wound repair by shifting macrophage polarization toward the anti-inflammatory M2 phenotype via suppressing ROS-NF-κB pathway. These results indicate that the use of porous Se@SiO₂ nanosphere-coated catheter may provide a therapeutic strategy for postoperative complications during prostatic urethra wound healing to improve patient quality of life.

Polydopamine/puerarin nanoparticle-incorporated hybrid hydrogels for enhanced wound healing

Oxidative damage generated would disrupt the oxidant/antioxidant balance in cells, causing slow wound healing and tissue regeneration. Hydrogel dressing with antioxidant properties can promote wound healing, however, its design is still a challenge.