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Abstract Tumor-infiltrating immune cells and fibroblasts are significant components of the tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC), and they participate in tumor progression as closely as tumor cells. However, the relationship between the features of the TME and patient outcomes and the interactions among TME components are still unclear. In this study, we evaluated the PDAC TME in terms of the quantity and location of cluster of differentiation (CD)4+ T cells, CD8+ T cells, macrophages, stromal maturity, and tumor-stroma ratio (TSR), as evaluated by immunohistochemical staining of serial whole-tissue sections from 116 patients with PDAC. The density of T cells and macrophages (mainly activated macrophages) was significantly higher at the invasive margins (IMs) than at the tumor center (TC). CD4+ T cells were significantly association with all the other tumor-associated immune cells (TAIs) including CD8, CD68 and CD206 positive cells. Tumors of the non-mature (intermediate and immature) stroma type harbored significantly more CD8+ T cells at the IMs and more CD68+ macrophages at the IMs and the TC. The density of CD4+, CD8+, and CD206+ cells at the TC; CD206+ cells at the IMs; and tumor-node-metastasis (TNM) staging were independent risk factors for patient outcomes, and the c-index of the risk nomogram for predicting the survival probability based on the TME features and TNM staging was 0.772 (95% confidence interval: 0.713–0.832). PDAC harbored a significantly immunosuppressive TME, of which the IMs were the hot zones for TAIs, while cells at the TC were more predictive of prognosis. Our results indicated that the model based on the features of the TME and TNM staging could predict patient outcomes.

Background: Sarcopenia is an age-related condition that causes loss of skeletal muscle mass and disability. Sarcopenia is closely related to the prognosis of patients suffering osteoporotic thoraco-lumbar compression fractures (OTLCF). The purpose of this study was to investigate the effect of sarcopenia on the efficacy of percutaneous kyphoplasty (PKP) in the treatment of older adults with OTLCF surgery and postoperative mortality. Methods: From February 2016 to June 2019, 101 patients who met the inclusion and exclusion criteria were included in this study. The grip strength of the dominant hand was measured using an electronic grip tester. The diagnostic cutoff value of grip strength for sarcopenia was

Biomaterials have been widely used as substitutes for diseased tissue in surgery and have gained great success and attention. At present, the biocompatibility of biomaterials such as PET woven fabrics is often evaluated both in vitro and in vivo. However, the current experimental methods cannot reveal the relationship between material surfaces and cell adhesion, and few research works have focused on the mechanisms of how the surface morphology of biomaterials affects cell adhesion and proliferation. Thus, it is meaningful to find out how the altered surfaces could affect cell adhesion and growth. In this study, we employed Ar low-temperature plasma treatment technology to create nano-grooves on the warp yarn of PET woven fabrics and seeded human umbellar vein endothelial cells (HUVEC) on these fabrics. We then assessed the O-glycan and N-glycan profiles of the cells grown on different structures of the polyester woven fabrics. The result showed that the surface morphology of polyester woven fabrics could affect the O-glycan profile but not the N-glycan profile of cultured HUVEC. Taken together, the study describes the effects of the surface morphology of biomaterial on the biosynthesis of cellular glycans and may provide new insights into the design and manufacture of biomaterials used as blood vessels based on the expression profiles of O-glycans on cultured cells.

Water permeability of textile vascular grafts has been considered as a key indicator for predicting blood permeability after implantation. However, a correlation between water and blood permeability has not been established yet. Therefore, even though the water permeability of a vascular graft can be tested according to the standard ISO 7198, the results fail to guide a manufacturer or a surgeon to judge whether this vascular graft needs pre-clotting or not prior to implantation. As a result, all commercial graft products show almost zero water permeability, which leads to the loss of advantages that textile vascular grafts have the pore size-controlled porous wall. To solve this problem, four types of woven vascular grafts were designed and manufactured in the present work. Then their permeability to water, simulated plasma, and anticoagulated whole blood were measured at graded pressures from 8 to 16 kPa. Moreover, the correlations among the water permeability, the simulated plasma permeability, and the anticoagulated whole blood permeability were established. The results suggest that relatively steady correlations exist between the water permeability and the anticoagulated whole blood permeability, and that the evaluation of the blood permeability using the water permeability is feasible and objective. The present work provides a quantitative method for evaluating the blood permeability using the water permeability, and the latter is thus endowed with practical significance for guiding designs and clinical pre-clotting operations of textiles vascular grafts.

Stents have been widely used in percutaneous surgery to treat stenosis diseases. The braided NiTi stent, as a promising prototype, still has limitations of low radial force and loose structure. In the present study, a newly integrated composite stent was designed and braided with NiTi wires and polyester multifilament yarns by textile technology. The mechanical properties of four composite stents and the control bare NiTi stent were evaluated by in vitro compression, bending and anti-torsion tests. The results showed that integrated polyester/NiTi composite stents were superior in radial support. The stents could keep patency even when highly curved and had lower stent straightening force. Composite stents with certain structure stayed stable under twisting. The configuration of NiTi wires in composite stents could significantly impact stent deformation under twisting. Keywords: Vascular stent, Mechanical performance, Compression, Bending, Torsion

To enhance the hemocompatibility of silk fibroin fabric as biomedical material, polyelectrolytes architectures have been assembled through the layer-by-layer (LbL) technique on silk fibroin fabric (SFF). In particular, 1.5 and 2.5 bilayer of oppositely charged polyelectrolytes were assembled onto SFF using poly(allylamine hydrochloride) (PAH) as polycationic polymer and poly(acrylic acid) (PAA) as polyanionic polymer with PAH topmost. Low molecular weight heparin (LMWH) activated with 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) was then immobilized on its surface. Alcian Blue staining, toluidine blue assay and X-ray photoelectron spectroscopy (XPS) confirmed the presence of heparin on modified SFF surfaces. The surface morphology of the modified silk fibroin fabric surfaces was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and obtained increased roughness. Negligible hemolytic effect and a higher concentration of free hemoglobin by a kinetic clotting time test ensured the improved biological performance of the modified fibroin fabric. Overall, the deposition of 2.5 bilayer was found effective in terms of biological and surface properties of the modified fibroin fabric compared to 1.5 bilayer self-assembly technique. Therefore, this novel approach to surface modification may demonstrate long term patency in future in vivo animal trials of small diameter silk fibroin vascular grafts.

Acute thrombosis remains the main limitation of small-diameter vascular grafts (inner diameter

Silk-based medical products have a long history of use as a material for surgical sutures because of their desirable mechanical properties. However, silk fibroin fabric has been reported to be haemolytic when in direct contact with blood. The layer-by-layer self-assembly technique provides a method for surface modification to improve the biocompatibility of silk fibroin fabrics. Regenerated silk fibroin and alginate, which have excellent biocompatibility and low immunogenicity, are outstanding candidates for polyelectrolyte deposition. In this study, silk fabric was degummed and positively charged to create a silk fibroin fabric that could undergo self-assembly. The multilayer self-assembly of the silk fibroin fabric was achieved by alternating the polyelectrolyte deposition of a negatively charged alginate solution (pH = 8) and a positively charged regenerated silk fibroin solution (pH = 2). Finally, the negatively charged regenerated silk fibroin solution (pH = 8) was used to assemble the outermost layer of the fabric so that the surface would be negatively charged. A stable structural transition was induced using 75% ethanol. The thickness and morphology were characterised using atomic force microscopy. The properties of the self-assembled silk fibroin fabric, such as the bursting strength, thermal stability and flushing stability, indicated that the fabric was stable. In addition, the cytocompatibility and haemocompatibility of the self-assembled silk fibroin fabrics were evaluated. The results indicated that the biocompatibility of the self-assembled multilayers was acceptable and that it improved markedly. In particular, after the self-assembly, the fabric was able to prevent platelet adhesion. Furthermore, other non-haemolytic biomaterials can be created through self-assembly of more than 1.5 bilayers, and we propose that self-assembled silk fibroin fabric may be an attractive candidate for anticoagulation applications and for promoting endothelial cell adhesion for vascular prostheses.

Limb lengthening is frequently utilized in treating limb length inequalities, angulation deformities, nonunions, complex fractures, and deficiencies after tumor resection in more recent year. The procedure of limb lengthening pioneered by Ilizarov is now a widely accepted method for correcting limb length inequality and short stature as well as for bridging large defects in long bones. In order to promote bone healing during distraction osteogenesis and reduce the complications caused by limb lengthening pioneered, an alginate/nanohydroxyapatite/collagen (Alg/nHAC) composite was fabricated. General observation, histologically morphological observations, X-ray examination, biomechanical test, bone density, and the percentage area of bone trabecula were used to assay the ability of Alg/nHAC composite to promote bone healing. The present study demonstrates that the injection of liquid Alg/nHAC composites can significantly promote distraction osteogenesis. Alg/nHAC composite is promising for clinical application, solving the healing problem of backbone osteotomy and the fixing problem of metaphyseal backbone.

Background: In this study, we fabricated prototype bicomponent polyester/silk fibroin small-diameter arterial prostheses using a specially designed narrow ribbon shuttle loom. Methods: The 2-layered flat fabrics were then heatset on a mandrel to form tubes with a round cross section. Results: The woven samples had a wall thickness between 0.23 mm and 0.29 mm and an inner diameter between 3.53 mm and 3.95 mm, depending on the yarn type and the weave structure. Conclusions: The bicomponent polyester/silk fibroin samples had superior bursting strength, circumferential strength and suture retention strength compared with a commercial small-diameter arterial prosthesis made from ePTFE. In addition, these prototype samples had greater suture retention strengths than a dog femoral artery, which indicates that they have adequate biostability for clinical use. While their amount of radial compliance was superior to that of the ePTFE commercial graft control, it did not match that of a natural artery. So there is still a need for future improvement in compliance. All of the woven prototypes had water permeability values between 26 and 180 ml/(cm²*min), which confirms that none of these arterial prostheses needs to be preclotted at the time of implantation. The biocompatibility of the woven prototypes was evaluated using porcine endothelial cells and an MTT assay. Their cytocompatibility was found to be superior to the ePTFE commercial control, and the level of cell attachment was observed to increase on these prototypes woven with a higher silk fibroin content. [ABSTRACT FROM AUTHOR]

Hemocompatibility test is very common and important during development of biomaterials in direct contact with blood. Moreover, silk fibroin based biomaterials have been used in biomedical application for more than one hundred years and increasing sharply. Recent reports from our group and others have demonstrated that it has acceptable mechanical properties and patency rates in animal models. Unfortunately, pure silk fibroin shows poor hemocompatibility. Thus, the surface of a silk fibroin should be modified to improve its blood compatibility when it is used as a blood-contacting material especially for small diameter arterial prostheses. Researchers have studied hemocompatibility of silk fibroin biomaterials; however, the testing procedures vary greatly throughout different publication. Thus it is not easy to get the exact information from the literatures to performing hemocompatibility assays. Therefore, this paper reviews the studies on effects of surface modification on hemocompatibility in terms of hemolysis, anticoagulation, platelets adhesion, plasma recalcification time (PRT), activated partial thromboplastin time (APTT) and plasma prothrombin time (PT) assays of silk fibroin biomaterials. At last, other physical and biological tests which are also essential and related to the hemocompatibility testing, were also discussed in this paper. [ABSTRACT FROM AUTHOR]

To enhance the hemocompatibility of silk fibroin fabric as biomedical material, polyelectrolytes architectures have been assembled through the layer-by-layer (LbL) technique on silk fibroin fabric (SFF). In particular, 1.5 and 2.5 bilayer of oppositely charged polyelectrolytes were assembled onto SFF using poly(allylamine hydrochloride) (PAH) as polycationic polymer and poly(acrylic acid) (PAA) as polyanionic polymer with PAH topmost. Low molecular weight heparin (LMWH) activated with 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) was then immobilized on its surface. Alcian Blue staining, toluidine blue assay and X-ray photoelectron spectroscopy (XPS) confirmed the presence of heparin on modified SFF surfaces. The surface morphology of the modified silk fibroin fabric surfaces was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and obtained increased roughness. Negligible hemolytic effect and a higher concentration of free hemoglobin by a kinetic clotting time test ensured the improved biological performance of the modified fibroin fabric. Overall, the deposition of 2.5 bilayer was found effective in terms of biological and surface properties of the modified fibroin fabric compared to 1.5 bilayer self-assembly technique. Therefore, this novel approach to surface modification may demonstrate long term patency in future in vivo animal trials of small diameter silk fibroin vascular grafts. [ABSTRACT FROM AUTHOR]

The repair of the damaged bone tissue caused by damage or bone disease was still a problem. Current strategies including the use of autografts and allografts have the disadvantages, namely, diseases transmission, tissue availability and donor morbidity. Bone tissue engineering has been developed and regarded as a new way of regenerating bone tissues to repair or substitute damaged or diseased ones. The main limitation in engineering in vitro tissues is the lack of a sufficient blood vessel system, the vascularization. In this paper, a new-typed hydroxyapatite/collagen composite scaffold which was reinforced by chitosan fibers and cultured with osteoblasts and endothelial cells was fabricated. General observation, histological observation, detection of the degree of vascularization, and X-ray examination had been done to learn the effect of vascularized bone repair materials on the regeneration of bone. The results show that new vessel and bone formed using implant cultured with osteoblasts and endothelial cells. Nanofiber-reinforced scaffold cultured with osteoblasts and endothelial cells can induce vascularized bone tissue formation. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to explore the mechanism of the angiogenesis modes in the biomaterials implanted in vivo. By means of experimental observation and analysis of the capillary growing state in the porous silk fibroin film implanted into rats, we intended to develop a modeling expression on the growth mode of the capillaries in the biomaterials. Additionally, we proposed the response model of endothelial cells (ECs) resulting from vascular endothelial growth factor's concentrations at different stages after the implantation. With the implantation experiment, it was identified that angiogenesis developed in the way of capillary sprouting at the early stage of implantation and of intussusception at the late stage. Based on the response model of ECs, experimental results are explained. [ABSTRACT FROM AUTHOR]

Studies on skin substitutes and dermal scaffolds have been extensively carried out in the past several decades and some commercial products derived from collagen and polymers have been in marketing. Yet little research on silk fibroin based dermal scaffolds and products has been reported so far. In the present study, therefore, porous silk fibroin scaffolds (PSFSs) have been prepared by freeze drying method. The effects of PSFSs on skin recovery from full thickness defect have been examined by histological evaluation with respect to neovascularization, dermal regeneration and infiltration of inflammatory cells. In addition, tissue compatibility between PSFSs and polyvinyl alcohol (PVA) sponges (as control) has been semiquantitatively compared by scoring method. The results showed that at day 18 after implantation, new tissues formed in PSFSs whose structure was almost equal to normal skin structure where proportional distribution of functional blood vessels could be found. Furthermore, infiltration of inflammatory cells in PSFSs disappeared within 7 days. By contrast, a variety of interstices, fibrous encapsulization and moderate infiltration of inflammatory cells could be found in PVA sponges at day18 after implantation. In summary, PSFSs has significantly promoted the skin recovery from full thickness defect, showing fibroin's outstanding tissue compatibility. [ABSTRACT FROM AUTHOR]