Osteoinductive Dental Pulp Stem Cell-Derived Extracellular Vesicle-Loaded Multifunctional Hydrogel for Bone Regeneration.

Stem cell-derived extracellular vesicles (EVs) show great potential for promoting bone tissue regeneration. However, normal EVs (Nor-EVs) have a limited ability to direct tissue-specific regeneration. Therefore, it is necessary to optimize the osteogenic capacity of EV-based systems for repairing extensive bone defects. Herein, we show that hydrogels loaded with osteoinductive dental pulp stem cell-derived EVs (Ost-EVs) enhanced bone tissue remodeling, resulting in a 2.23 ± 0.25-fold increase in the expression of bone morphogenetic protein 2 (BMP2) compared to the hydrogel control group. Moreover, Ost-EVs led to a higher expression of alkaline phosphatase (ALP) (1.88 ± 0.16 of Ost-EVs relative to Nor-EVs) and the formation of orange-red calcium nodules (1.38 ± 0.10 of Ost-EVs relative to Nor-EVs) in vitro. RNA sequencing revealed that Ost-EVs showed significantly high miR-1246 expression. An ideal hydrogel implant should also adhere to surrounding moist tissues. In this study, we were drawn to mussel-inspired adhesive modification, where the hydrogel carrier was crafted from hyaluronic acid (HA) and polyethylene glycol derivatives, showcasing impressive tissue adhesion, self-healing capabilities, and the ability to promote bone growth. The modified HA (mHA) hydrogel was also responsive to environmental stimuli, making it an effective carrier for delivering EVs. In an ectopic osteogenesis animal model, the Ost-EV/hydrogel system effectively alleviated inflammation, accelerated revascularization, and promoted tissue mineralization. We further used a rat femoral condyle defect model to evaluate the in situ osteogenic ability of the Ost-EVs/hydrogel system. Collectively, our results suggest that Ost-EVs combined with biomaterial-based hydrogels hold promising potential for treating bone defects.

Cardiac patches made of brown adipose-derived stem cell sheets and conductive electrospun nanofibers restore infarcted heart for ischemic myocardial infarction.

Cell sheet engineering has been proven to be a promising strategy for cardiac remodeling post-myocardial infarction. However, insufficient mechanical strength and low cell retention lead to limited therapeutic efficiency. The thickness and area of artificial cardiac patches also affect their therapeutic efficiency. Cardiac patches prepared by combining cell sheets with electrospun nanofibers, which can be transplanted and sutured to the surface of the infarcted heart, promise to solve this problem. Here, we fabricated a novel cardiac patch by stacking brown adipose-derived stem cells (BADSCs) sheet layer by layer, and then they were combined with multi-walled carbon nanotubes (CNTs)-containing electrospun polycaprolactone/silk fibroin nanofibers (CPSN). The results demonstrated that BADSCs tended to generate myocardium-like structures seeded on CPSN. Compared with BADSCs suspension-containing electrospun nanofibers, the transplantation of the CPSN-BADSCs sheets (CNBS) cardiac patches exhibited accelerated angiogenesis and decreased inflammation in a rat myocardial infarction model. In addition, the CNBS cardiac patches could regulate macrophage polarization and promote gap junction remodeling, thus restoring cardiac functions. Overall, the hybrid cardiac patches made of electrospun nanofibers and cell sheets provide a novel solution to cardiac remodeling after ischemic myocardial infarction.

Disruption of hematopoiesis attenuates the osteogenic differentiation capacity of bone marrow stromal cells.

BACKGROUND: The homeostasis of mesenchymal stem cells (MSCs) is modulated by both their own intracellular molecules and extracellular milieu signals. Hematopoiesis in the bone marrow is maintained by niche cells, including MSCs, and it is indispensable for life. The role of MSCs in maintaining hematopoietic homeostasis has been fully elucidated. However, little is known about the mechanism by which hematopoietic cells reciprocally regulate niche cells. The present study aimed to explore the close relationship between MSCs and hematopoietic cells, which may be exploited for the development of new therapeutic strategies for related diseases. METHODS: In this study, we isolated cells from the offspring of Tie2Cre + and Ptenflox/flox mice. After cell isolation and culture, we investigated the effect of hematopoietic cells on MSCs using various methods, including flow cytometry, adipogenic and osteogenic differentiation analyses, quantitative PCR, western bloting, and microCT analysis. RESULTS: Our results showed that when the phosphatase and tensin homolog deleted on chromosome 10 (Pten) gene was half-deleted in hematopoietic cells, hematopoiesis and osteogenesis were normal in young mice; the frequency of erythroid progenitor cells in the bone marrow gradually decreased and osteogenesis in the femoral epiphysis weakened as the mice grew. The heterozygous loss of Pten in hematopoietic cells leads to the attenuation of osteogenic differentiation and enhanced adipogenic differentiation of MSCs in vitro. Co-culture with normal hematopoietic cells rescued the abnormal differentiation of MSCs, and in contrast, MSCs co-cultured with heterozygous null Pten hematopoietic cells showed abnormal differentiation activity. Co-culture with erythroid progenitor cells also revealed them to play an important role in MSC differentiation. CONCLUSION: Our data suggest that hematopoietic cells function as niche cells of MSCs to balance the differentiation activity of MSCs and may ultimately affect bone development.

Characterization and evaluation of a novel silver nanoparticles-loaded polymethyl methacrylate denture base: In vitro and in vivo animal study.

The aim of this study was to optimize the preparation method of polymethyl methacrylate (PMMA) denture base loaded with nano silver (NAg), to more effectively and safely impart sustainable antibacterial functions. NAg solution was synthetized and mixed with acrylic acid and methyl methyacrylate (MMA) monomer in order to prepare a new type of NAg solution (NS)/polymer methyl methacrylate denture base specimens (NS/PMMA). The surface morphology, mechanical strength, antimicrobial activity, anti-aging performance, cytotoxicity and biocompatibility of NS/PMMA denture base were evaluated in comparison with specimens fabricated using traditional NAg adding methods and NAg-free denture base. The aesthetic characteristics and mechanical strength of NS/PMMA denture base met the clinical application requirements. Meanwhile, NS/PMMA denture base showed better antibacterial activity, anti-aging properties, no cytotoxicity and displayed exceptional biocompatibility. NS/PMMA denture base thus has great potential for clinical application.

Improving Chronic Diabetic Wound Healing through an Injectable and Self-Healing Hydrogel with Platelet-Rich Plasma Release.

Diabetic skin ulcer is one of the severe complications of diabetes mellitus, which has a high incidence and may cause death or disability. Platelet-rich plasma (PRP) is widely used in the treatment of diabetic wounds due to the effect of growth factors (GFs) derived from it. However, the relatively short half-life of GFs limits their applications in clinics. In addition, the presence of a large amount of proteases in the diabetic wound microenvironment results in the degradation of GFs, which further impedes angiogenesis and diabetic wound healing. In our study, we fabricated a self-healing and injectable hydrogel with a composite of chitosan, silk fibroin, and PRP (CBPGCTS-SF@PRP) for promoting diabetic wound healing. CBPGCTS-SF@PRP could protect PRP from enzymatic hydrolysis, release PRP sustainably, and enhance the chemotaxis of mesenchymal stem cells. The results showed that it could promote the proliferation of repair cells in vitro. Moreover, it could enhance wound healing by expediting collagen deposition, angiogenesis, and nerve repair in a type 2 diabetic rat model and a rat skin defect model. We hope that this study will offer a new treatment for diabetic nonhealing wounds in clinics.

A New Self-Healing Hydrogel Containing hucMSC-Derived Exosomes Promotes Bone Regeneration.

BACKGROUND: Fractures are a medical disease with a high incidence, and about 5-10% of patients need bone transplantation to fill the defect. In this study, we aimed to synthesize a new type of coralline hydroxyapatite (CHA)/silk fibroin (SF)/glycol chitosan (GCS)/difunctionalized polyethylene glycol (DF-PEG) self-healing hydrogel and to evaluate the therapeutic effects of this novel self-healing hydrogel as a human umbilical cord mesenchymal stem cells (hucMSC)-derived exosome carrier on bone defects in SD rat. METHODS: HucMSCs were isolated from fetal umbilical cord tissue and characterized by surface antigen analysis and pluripotent differentiation in vitro. The cell supernatant after ultracentrifugation was collected to isolate exosomes, which were characterized by transmission electron microscopy and western blot analysis. In vitro cell induction experiments were performed to observe the effects of hucMSC-derived exosomes on the biological behavior of mouse osteoblast progenitor cells (mOPCs) and human umbilical vein endothelial cells (HUVECs). The CHA/SF/GCS/DF-PEG hydrogels were prepared using DF-PEG as the gel factor and then structural and physical properties were characterized. HucMSCs-derived exosomes were added to the hydrogel and their effects were evaluated in SD rats with induced femoral condyle defect. These effects were analyzed by X-ray and micro-CT imaging and H&E, Masson and immunohistochemistry staining. RESULTS: HucMSC-derived exosomes can promote osteogenic differentiation of mOPCs and promote the proliferation and migration of HUVECs. The CHA/SF/GCS/DF-PEG hydrogel has a high self-healing capacity, perfect surface morphology and the precipitated CHA crystals have a small size and low crystallinity similar to natural bone minerals. The MTT results showed that the hydrogel was non-toxic and have a good biocompatibility. The in vivo studies have shown that the hydrogel containing exosomes could effectively promote healing of rat bone defect. The histological analysis revealed more new bone tissue and morphogenetic protein 2 (BMP-2) in the hydrogel-exosome group. In addition, the hydrogel-exosome group had the highest microvessel density. CONCLUSION: A self-healing CHA/SF/GCS/DF-PEG hydrogel was successfully prepared. The hydrogel has excellent comprehensive properties and is expected to become a new type of bone graft material. This hydrogel has the effect of promoting bone repair, which is more significant after the addition of hucMSC-derived exosomes.

Neuregulin 4 alleviates hepatic steatosis via activating AMPK/mTOR-mediated autophagy in aged mice fed a high fat diet.

Neuregulin 4 (Nrg4) is a brown fat-enriched endocrine factor that exerts beneficial metabolic effects on insulin resistance and hepatic steatosis. Autophagy is a mechanism that is essential for preventing hepatic steatosis. The aim of this study was to explore whether Nrg4 ameliorates hepatic steatosis by inducing autophagy. Aged C57BL/6 mice were maintained on a high fat diet with or without Nrg4 intervention for 3 months. Lipid accumulation in the liver was investigated. Autophagy related protein levels along with related signaling pathways that regulate autophagy were evaluated. In addition, the effects of Nrg4 on autophagy were also determined in cultured L-02 cells. Nrg4 decreased high-fat induced intrahepatic lipid content both in vivo and in vitro. Autophagy level in the liver also decreased in obese mice and Nrg4 intervention reactivated autophagy. Further, Nrg4 intervention was found to have activated autophagy via the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling pathway. Moreover, when the AMPK/mTOR pathway was suppressed or autophagy was inhibited, the beneficial effects of Nrg4 intervention on hepatic steatosis were diminished. These results indicated that Nrg4 intervention attenuated hepatic steatosis by promoting autophagy in the liver of aged obese mice. Additionally, Nrg4 induced autophagy via the AMPK/mTOR signaling pathway.

A moisturizing chitosan-silk fibroin dressing with silver nanoparticles-adsorbed exosomes for repairing infected wounds.

Refractory wounds caused by microbial infection impede wound healing, vascular regeneration, nerve system repair and the regeneration of other skin appendages. In addition, large-area infected wounds cause the appearance of multidrug-resistant (MDR) bacterial strains, which pose a major challenge both in clinical and scientific research. Although many stem cell-derived exosomes have been demonstrated to promote skin repair and regeneration, exosomes are seldom applied in the treatment of infective wounds due to the lack of antimicrobial function. In this study, we fabricated an asymmetric wettable dressing with a composite of exosomes and silver nanoparticles (CTS-SF/SA/Ag-Exo dressing) for promoting angiogenesis, nerve repair and infected wound healing. The CTS-SF/SA/Ag-Exo dressing possesses multifunctional properties including broad-spectrum antimicrobial activity, promoting wound healing, retaining moisture and maintaining electrolyte balance. It can effectively inhibit the growth of bacterial and promote the proliferation of human fibroblasts in vitro. Moreover, the in vivo results show that the CTS-SF/SA/Ag-Exo dressing enhanced wound healing by accelerating collagen deposition, angiogenesis and nerve repair in a P. aeruginosa infected mouse skin wound defect model. We hope that this dressing will provide a solution for the repair of infected wounds for treatments in the clinic.

Integration of C-type natriuretic peptide gene-modified bone marrow mesenchymal stem cells with chitosan/silk fibroin scaffolds as a promising strategy for articular cartilage regeneration.

The treatment of articular cartilage defects has become a major clinical concern. Currently, additional efforts are necessary to develop effective methods to cure this disease. In this work, we combined gene therapy with tissue engineering methods to test their effect on cartilage repair. In in vitro experiments, we obtained C-type natriuretic peptide (CNP) gene-modified bone marrow-derived mesenchymal stem cells (BMSCs) by transfection with recombinant adenovirus containing the CNP gene and revealed that CNP gene-modified BMSCs had good chondrogenic differentiation ability. By the freeze-drying method, we successfully synthesized a chitosan/silk fibroin (CS/SF) porous scaffold, which had a suitable aperture size for chondrogenesis. Then, we loaded CNP gene-modified BMSCs onto CS/SF scaffolds and tested their effect on repairing full-thickness cartilage defects in rat joints. The gross morphology and histology examination results showed that the composite of the CNP gene-modified BMSCs and CS/SF scaffolds had better repair effects than those of the other three groups at each time point. Additionally, compared to the group with BMSCs and scaffolds, we found that there was more cartilage matrix in the CNP gene-modified BMSCs and CS/SF scaffolds group. Data obtained in the present study suggest that the composite of CNP gene-modified BMSCs and CS/SF scaffolds represent promising strategies for repairing focal cartilage lesions.

The immune influence of a parabiosis model on tumour-bearing mice.

AIM: The aim of this study was to analyse the immune influence of a parabiosis model on tumour-bearing mice. METHODS: Parabiosis was established between C57BL/6 wild-type mice expressing green fluorescent protein (GFP+) and C57BL/6 wild-type mice without green fluorescent protein (GFP) to ensure blood cross-circulation between animals, and then the expression of CD4+ T cells, CD8+ T cells and interleukins 2, 4 and 10, and interferon-gamma (INF-γ) in spleen cells of parabiosis model mice were examined with flow cytometry. At day 8 and day 14 after conjoined surgery, we were aiming to sample tumour tissue in the parabiosis mice and observe changes of CD3, CD4, CD8, CD31, IFN-γ and vascular endothelial growth factor (VEGF) through immunohistochemical analysis. RESULTS: The interaction of blood was established on the third day with modelling rate of 85.7% after blood interaction. The healthy cells of GFP+ C57 mice entered the blood circulation of tumour-bearing mice via a connecting capillary network, playing a role in stimulating CD4+ and CD8+ cells in the tumour-bearing mice so that CD4+ cells increased more in tumour-bearing mice than in the positive control group (p <0.05). The number of GFP+ cells that were detected in a tumour-bearing mouse was small, but GFP+ cells can stimulate the mouse itself to generate more CD4+/interleukin (IL)-4, CD4+/IL-10 (p <0.05).The numbers of CD4+/IL-2, CD4+/IL-4 and CD4+/IL-10 among the GFP+ mice were higher than those in the negative control group(p <0.05).The levels of IFN-γ in both mice in the parabiosis model were decreased (p <0.05). The rate of CD4+/CD8+ in parabiosis GFP+ mice was higher than in the negative control group (p <0.05). In immunohistochemical tests, the rates of CD3, CD4, CD8 and IFN-γ positive cells was higher than in the positive control group, with their optical densities of 0.32 ± 0.63, 0.33 ± 0.00, 0.31 ± 0.91 and 0.28 ± 0.14 respectively (p <0.05). The expression of CD31 (0.19 ± 0.50) and VEGF (0.19 ± 0.21) were lower when compared with the positive control group, with no significant difference. CD31 and VEFG cell expression was low, at 0.19 ± 0.50 and 0.19 ± 0.21, respectively, compared with the positive control group (p >0.05). Values for CD31 and VEGF cells in the positive control group were higher, at 0.32 ± 0.35 and 0.29 ± 0.35, respectively, but when compared with the parabiosis tumour-bearing group, there was no significant difference. The expression of CD3, CD4, CD8 and IFN-γ cells at day 8 was low: 0.22, 0.17, 0.15 and 0.16, respectively. When compared with the parabiosis tumour-bearing group, there was no significant difference. CONCLUSIONS: The established allogeneic parabiosis mice model can be well adapted to the conjoined state of mice and be applied in wide medical experiments. The parabiosis model has played an important role in studying immune regulation, which provides a basis for the future tumour immunotherapy. Parabiosis models can stimulate tumour-bearing mice to generate CD3, CD4, CD8 and IFN-γ, and play a notable role in immune regulation and tumour destruction. The positive expression rates of CD31 and VEFG cells in the parabiosis tumour-bearing group were lower; however, when compared with the positive control group, there was no significant difference.

GMSC-Derived Exosomes Combined with a Chitosan/Silk Hydrogel Sponge Accelerates Wound Healing in a Diabetic Rat Skin Defect Model.

Background: Delayed wound healing in diabetic patients is one of the most challenging complications in clinical medicine, as it poses a greater risk of gangrene, amputation and even death. Therefore, a novel method to promote diabetic wound healing is of considerable interest at present. Previous studies showed that injection of MSC-derived exosomes has beneficial effects on wound healing. In current studies, we aimed to isolate exosomes derived from gingival mesenchymal stem cells (GMSCs) and then loading them to the chitosan/silk hydrogel sponge to evaluate the effects of this novel non-invasive method on skin defects in diabetic rats. Methods: GMSCs were isolated from human gingival connective tissue and characterized by surface antigen analysis and in vitro multipotent differentiation. The cell supernatant was collected to isolate the exosomes. The exosomes were characterized by transmission electron microscopy, Western blot and size distribution analysis. The chitosan/silk-based hydrogel sponge was prepared using the freeze-drying method and then structural and physical properties were characterized. Then, the exosomes were added to the hydrogel and tested in a diabetic rat skin defect model. The effects were evaluated by wound area measurement, histological, immunohistochemical and immunofluorescence analysis. Results: We have successfully isolated GMSCs and exosomes with a mean diameter of 127 nm. The chitosan/silk hydrogel had the appropriate properties of swelling and moisture retention capacity. The in vivo studies showed that the incorporating of GMSC-derived exosomes to hydrogel could effectively promote healing of diabetic skin defects. The histological analysis revealed more neo-epithelium and collagen in the hydrogel-exosome group. In addition, the hydrogel-exosome group had the highest microvessel density and nerve density. Conclusions: The combination of GMSC-derived exosomes and hydrogel could effectively promote skin wound healing in diabetic rats by promoting the re-epithelialization, deposition and remodeling of collagen and by enhancing angiogenesis and neuronal ingrowth. These findings not only provide new information on the role of the GMSC-derived exosomes in wound healing but also provide a novel non-invasive application method of exosomes with practical value for skin repair.

Synthesis, characterization and antibacterial study on the chitosan-functionalized Ag nanoparticles.

This study provided a facile, one-step hydrothermal method to synthesize stable Ag colloid in aqueous solution by utilizing chitosan as both reductant and stabilizer. The formation of chitosan-functionalized Ag nanoparticles was verified by UV-Vis, FTIR, TEM, AFM and XRD measurements. FTIR results revealed that the primary amine groups and amide groups of chitosan have specific interactions with the surface of Ag nanoparticles. The average diameter of the Ag nanoparticles is 10.0±5.4nm as determined by TEM. Ag nanoparticles are highly crystalline as revealed by HR-TEM and XRD measurements. The size and shape of Ag nanoparticles are also found to depend on the pH condition in the synthesis. Ag nanoparticles were the main products at pH5.0 whereas large Ag nanotriangle and truncated triangular nanoplate were dominant at pH4.0 in the synthesis. Due to its monodispersity and good stability, the chitosan-functionalized Ag colloid synthesized at pH5.0 was further tested for its antibacterial activities against gram-positive bacteria, gram-negative bacteria and fungus. The results of zone of inhibition, inhibition ratio and SEM characterization revealed that chitosan-functionalized Ag nanoparticles have great bactericidal efficiency against both bacteria and fungus.

Thermally Triggered in Situ Assembly of Gold Nanoparticles for Cancer Multimodal Imaging and Photothermal Therapy.

The assembly of gold nanoparticles (AuNPs) to AuNP assemblies is of interest for cancer therapy and imaging. Herein we introduce a new and general paradigm, thermally triggered AuNP assembly, for the development of novel intelligent platforms for cancer photothermal therapy (PTT) and multimodal imaging. Site-specific conjugation of a thermally sensitive elastin-like polypeptide (ELP) to AuNPs yields thermally sensitive ELP-AuNPs. Interestingly, ELP-AuNPs can in situ form AuNP assemblies composed of short necklace-like gold nanostructures at elevated temperatures and thus show strong near-infrared light absorption and high photothermal effect. These thermally responsive properties of ELP-AuNPs enable simultaneous photothermal/photoacoustic/X-ray computed tomographic imaging and PTT of melanoma after single intratumoral injection of ELP-AuNPs. The thermally triggered assembly of a variety of nanoparticles with optical, electronic, and magnetic properties into nanoparticle assemblies may open new ways for the establishment of intelligent platforms for various applications in biomedicine.

Maintaining the Phenotype Stability of Chondrocytes Derived from MSCs by C-Type Natriuretic Peptide.

Mesenchymal stem cells (MSCs) play a critical role in cartilage tissue engineering. However, MSCs-derived chondrocytes or cartilage tissues are not stable and easily lose the cellular and cartilage phenotype during long-term culture in vitro or implantation in vivo. As a result, chondrocytes phenotypic instability can contribute to accelerated ossification. Thus, it is a big challenge to maintain their correct phenotype for engineering hyaline cartilage. As one member of the natriuretic peptide family, C-type natriuretic peptide (CNP) is found to correlate with the development of the cartilage, affect the chondrocytes proliferation and differentiation. Besides, based on its biological effects on protection of extracellular matrix of cartilage and inhibition of mineralization, we hypothesize that CNP may contribute to the stability of chondrocyte phenotype of MSCs-derived chondrocytes.

[Effects of PRX-2 gene on the phenotype changes of epidermal stem cells differentiating into sweat gland cells].

Objective: To investigate the effects of PRX-2 gene on phenotype changes in epidermal stem cells differentiating into sweat gland cells. Methods: Epidermal stem cells and sweat gland cells separated and cultured from healthy foreskin and adult full-thick skin respectively, were identified by immunofluorescence staining. Lentiviral vector-mediated overexpression and knockdown of PRX-2 gene in epidermal stem cells were performed respectively,with empty vector-mediated epidermal stem cells as a control group. Overexpression blank control and know down group's PRX-2 expressions in gene and protein levels were detected using RT-PCR and Western blot technology. The ESCs of each group were co-cultured with sweat gland cells through transwell plate, and the expressions of CEA and ß1 integrin in epidermal stem cells were determined by flow cytometry before and after co-culturing. Results: Epidermal stem cells and sweat gland cells were in line with their respective specific antigens .Before co-cultured, epidermal stem cells highly expressed ß1 integrin (98.69 ± 0.67)％,hardly expressed CEA (6.20 ± 3.15)％.After co-cultured,ß1 integrin expression levels were showed as knockdown group (19.30 ± 0.53) ％ ＜blank control group (65.77 ± 2.32)％ ＜ overexpress group (92.63 ± 10.97)％,and CEA expression levels as knockdown (95.43 ±2.36)％ ＞ blank control group (51.20 ±0.79)％ ＞ overexpress group (45.91 ±0.93)％.There had significant differences between those of each two groups. Conclusions: PRX-2 gene can inhibit the phenotypic change of Epidermal Stem Cells differentiating into Sweat Gland Cells and improve the ability to maintain their own specific antigens.

A porous sodium polyacrylate-grafted chitosan xerogel for severe hemorrhage control synthesized from one-pot reaction.

Controlling severe hemorrhages remains a challenge. Successful hemorrhage control depends on the speed and quality of blood clot formation. Fast deprivation of water from blood leads to the concentration of blood cells and coagulation factors and thus triggers blood clot formation. This inspired us to develop a new hemostatic material. In this study, we grafted sodium polyacrylate (SPA) onto the backbone of chitosan (CTS) and crosslinked with methacrylic anhydride-modified polyethylene glycol (MAAPEG) to provide a flexible and elastic inter-chain connection between SPA and CTS chains in the presence of a blowing agent to achieve a porous structure. By a simple one-pot reaction, we fabricated a soft, elastic porous xerogel sponge that could reach maximum water absorbency of 180 in less than 200 seconds. This SPA-co-chitosan xerogel sponge demonstrated superior hemostatic properties in thromboelastography (TEG®) test and in a rabbit lethal extremity arterial bleeding model as compared to zeolite granules, kaolin gauze, and chitosan granules. Furthermore, this hemostat worked as a whole to transfer external pressure to the bleeding area and was adhesive to wet wound tissue to seal the bleeding site. In general, the SPA-co-CTS sponge demonstrates a fast and powerful hemostatic effect both in vitro and in vivo, which is superior over the existing commercial products. It might be a promising first-aid device for severe hemorrhage control.

Antibacterial Adhesion of Poly(methyl methacrylate) Modified by Borneol Acrylate.

Poly(methyl methacrylate) (PMMA) is a widely used biomaterial. But there is still a challenge facing its unwanted bacterial adhesion because the subsequent biofilm formation usually leads to failure of related implants. Herein, we present a borneol-modified PMMA based on a facile and effective stereochemical strategy, generating antibacterial copolymer named as P(MMA-co-BA). It was synthesized by free radical polymerization and studied with different ratio between methyl methacrylate (MMA) and borneol acrylate (BA) monomers. NMR, GPC, and EA, etc., were used to confirm their chemical features. Their films were challenged with Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive), showing a BA content dependent antibacterial performance. The minimum effective dose should be 10%. Then in vivo subcutaneous implantations in mice demonstrated their biocompatibilities through routine histotomy and HE staining. Therefore, P(MMA-co-BA)s not only exhibited their unique antibacterial character but also suggested a potential for the safe usage of borneol-modified PMMA frame and devices for further implantation.

Silybin suppresses cell proliferation and induces apoptosis of multiple myeloma cells via the PI3K/Akt/mTOR signaling pathway.

Silybin is a biologically active component extracted from the seeds of Silybum marianum, which has been shown to have inhibitory effects on prostate, skin, bladder, lung and colon cancer cells, in addition to its efficacy in the treatment of liver diseases, including hepatitis and cirrhosis. The aim of the present study was to investigate whether silybin suppresses the proliferation and induces apoptosis of multiple myeloma (MM) cells and to elucidate its molecular targets. The proliferative and apoptotic rates of the U266 MM cell line were assessed using MTT and flow­cytometric assays, respectively. Western blot analysis was used to assess the protein levels of phosphoinositide­3 kinase (PI3K), phosphorylated (p)­Akt and p­mammalian target of rapamycin (mTOR) in U266 cells. In addition, PI3K inhibitor LY294002 or activator insulin­like growth factor 1 were used to investigate the involvement of the PI3K/Akt­mTOR signaling pathway in the effect of silybin on U266 cells. The results revealed that silybin restrained the proliferation and enhanced the apoptosis of U266 cells. Furthermore, silybin inhibited the protein expression of PI3K, p­Akt and p­mTOR in U266 cells. Of note, inhibition of PI3K facilitated silybin­mediated reduction of mTOR activation, cell proliferation and induction of apoptosis in U266 cells, while activation of PI3K attenuated the effects of silybin. In conclusion, silybin suppressed cell proliferation and promoted apoptosis of U266 cells via PI3K/Akt-mTOR signaling pathways.

[C3H10 T1/2 cells over-expressing CCR7 have intensive immunosuppressive effect].

OBJECTIVE: To evaluate whether the chemokine (C-C motif) receptor 7 (CCR7) over-expressing C3H10 T1/2 mesenchymal stem cells are more efficient in immunosuppression effects than the original ones in skin grafts in mice. METHODS: The C3H10 T1/2 cells were amplified and transfered with EGFP-CCR7 gene using lentivirus. The skin grafts were harvested from donators (C57BL/6 mice) and then transplanted to recipients (BALB/c mice). The recipients were divided into 4 groups randomly: CCR7⁺ C3H10 T1/2 group (1 × 106 CCR7⁺ C3H10 T1/2 cells suspended in 1 mL PBS were injected into the recipient mice by caudal vein), C3H10 T1/2 group (1 × 106 C3H10 T1/2 cells were injected into the recipient mice after skin graft), allogenic control group (the mice were injected with 1 mL normal saline), and congenic control group (the BALB/c mice that had received the skin from the congenic ones were injected with 1 mL normal saline). The skin graft survival condition and histopathological changes were observed on the 12th postoperative day. The Th17 cells and regulatory T cells (Tregs) in the lymphocytes of spleen were detected by mouse Th17/Treg phenotyping kit. RESULTS: On the 12th postoperative day, the skin surface features, histopathologic changes and flow cytometry results indicated that the skin graft survival condition of the allografts treated with CCR7⁺ C3H10 T1/2 or C3H10 T1/2 cells were better than that of the allogenic control group. Compared with C3H10 T1/2 cells, CCR7⁺ C3H10 T1/2 cells had better skin graft survival condition and weaker immune response. CONCLUSION: CCR7⁺ C3H10 T1/2 cells induce more intensive immunosuppressive effects than original C3H10 T1/2 cells. CCR7⁺ C3H10 T1/2 cells significantly inhibit inflammatory reaction and improve the living state of skin allograft.

CCR7 expressing mesenchymal stem cells potently inhibit graft-versus-host disease by spoiling the fourth supplemental Billingham's tenet.

The clinical acute graft-versus-host disease (GvHD)-therapy of mesenchymal stem cells (MSCs) is not as satisfactory as expected. Secondary lymphoid organs (SLOs) are the major niches serve to initiate immune responses or induce tolerance. Our previous study showed that CCR7 guide murine MSC line C3H10T1/2 migrating to SLOs. In this study, CCR7 gene was engineered into murine MSCs by lentivirus transfection system (MSCs/CCR7). The immunomodulatory mechanism of MSCs/CCR7 was further investigated. Provoked by inflammatory cytokines, MSCs/CCR7 increased the secretion of nitric oxide and calmed down the T cell immune response in vitro. Immunofluorescent staining results showed that transfused MSCs/CCR7 can migrate to and relocate at the appropriate T cell-rich zones within SLOs in vivo. MSCs/CCR7 displayed enhanced effect in prolonging the survival and alleviating the clinical scores of the GvHD mice than normal MSCs. Owing to the critical relocation sites, MSCs/CCR7 co-infusion potently made the T cells in SLOs more naïve like, thus control T cells trafficking from SLOs to the target organs. Through spoiling the fourth supplemental Billingham's tenet, MSCs/CCR7 potently inhibited the development of GvHD. The study here provides a novel therapeutic strategy of MSCs/CCR7 infusion at a low dosage to give potent immunomodulatory effect for clinical immune disease therapy.