Chitosan promotes aquaporin formation and inhibits mucociliary differentiation of nasal epithelial cells through increased TGF‐β1 production

Although endoscopic sinus surgery is the mainstay surgical treatment for chronic rhinosinusitis, over 15% of patients require a repeat operation wherein postoperative adhesion formation is one of the main causes of failure. Several recently proposed chitosan‐based biomaterials promote mucosal healing, reduce postoperative adhesion formation and restore mucociliary function of sinonasal mucosa. However, the effects of chitosan on cellular morphology, re‐epithelization, and mucociliary differentiation of nasal epithelial cells (NECs) during the wound healing process have not been thoroughly investigated. The present study investigates the direct effects of chitosan on cellular growth, cellular migration, mucociliary differentiation and aquaporin (AQP) formation of NECs to elucidate the role of chitosan in sinonasal applications. Wound healing assay reveals that proliferation and migration of NECs are inhibited by incubation of chitosan. The NECs become irregular in shape without formation of tight junction and mucociliary differentiation of NECs is inhibited during a culture period with incubation of chitosan. However, AQP3 and AQP5 formation in NECs is significantly higher in chitosan groups than in control groups. Further, expressions of transforming growth factor (TGF)‐β1, Smad2, and Smad3 are significantly higher in the chitosan groups compared with controls. The results of the comparison indicate that chitosan inhibits proliferation, migration and mucociliary differentiation of NECs through increasing production of TGF‐β1. Copyright © 2016 John Wiley & Sons, Ltd.     

Silk fibroin scaffolds with muscle‐like elasticity support in vitro differentiation of human skeletal muscle cells

Human adult skeletal muscle has a limited ability to regenerate after injury and therapeutic options for volumetric muscle loss are few. Technologies to enhance regeneration of tissues generally rely upon bioscaffolds to mimic aspects of the tissue extracellular matrix (ECM). In the present study, silk fibroins from four Lepidoptera (silkworm) species engineered into three‐dimensional scaffolds were examined for their ability to support the differentiation of primary human skeletal muscle myoblasts. Human skeletal muscle myoblasts (HSMMs) adhered, spread and deposited extensive ECM on all the scaffolds, but immunofluorescence and quantitative polymerase chain reaction analysis of gene expression revealed that myotube formation occurred differently on the various scaffolds. Bombyx mori fibroin scaffolds supported formation of long, well‐aligned myotubes, whereas on Antheraea mylitta fibroin scaffolds the myotubes were thicker and shorter. Myotubes were oriented in two perpendicular layers on Antheraea assamensis scaffolds, and scaffolds of Philosamia/Samia ricini (S. ricini) fibroin poorly supported myotube formation. These differences were not caused by fibroin composition per se, as HSMMs adhered to, proliferated on and formed striated myotubes on all four fibroins presented as two‐dimensional fibroin films. The Young's modulus of A. mylitta and B. mori scaffolds mimicked that of normal skeletal muscle, but A. assamensis and S. ricini scaffolds were more flexible. The present study demonstrates that although myoblasts deposit matrix onto fibroin scaffolds and create a permissive environment for cell proliferation, a scaffold elasticity resembling that of normal muscle is required for optimal myotube length, alignment, and maturation. © 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd. StartCopTextStartCopText© 2016 The Authors Journal of Tissue Engineering and Regenerative Medicine Published by John Wiley & Sons Ltd.     

从技术评价角度思考非生物型人工肝医用材料的特性

本文从技术评价角度阐述了现阶段非生物型人工肝医用材料特性研究的重点,论述了对非生物型人工肝医用材料技术审评的关注要点,提出了生物安全性评价中的几个现实性问题,以期共同探讨如何通过提高对非生物型人工肝医用材料技术评价以更好地推进非生物型人工肝医疗器械研发与评价的发展。     

Crosslinking of an oesophagus acellular matrix tissue scaffold

The oesophagus acellular matrix (EAM) tissue-scaffold has the potential to serve as the foundation for a tissue-engineered oesophagus for repair of ablative defects. Similar to all collagen-based biomaterials, the EAM is subject to enzymatic degradation in vivo. The introduction of exogenous crosslinks to collagen molecules via glutaraldehyde (Glu) is the most accepted method of stabilizing collagen biomaterials, but fixation with Glu incurs adverse effects. Genipin (Gp), a naturally occurring crosslinking agent, has shown to be effective at improving the stability of collagen-based biomaterials with less cytotoxicity and reduced in vivo inflammatory responses than Glu. The aim of this study was to show that crosslinking with Gp improves the stability of the EAM while maintaining minimal biological reactivity and preserving EAM regeneration potential in a rat model. EAMs were crosslinked with Gp and Glu. Uncrosslinked EAMs served as controls. Denaturation temperature measurement and burst-pressure measurement after enzymatic degradation assays were used to determine the effectiveness of crosslinking on in vitro stability. Subcutaneous allograft implantation and oesophageal epithelial cell-seeding studies assessed the crosslinking effects on biological reactivity and regeneration potential, respectively. Both Gp and Glu improved EAM stability. After 30 days of implantation, the EAM elicited a minimal inflammatory response and crosslinking did not increase inflammation. Gp-crosslinked EAMs supported epithelial adhesion and proliferation while Glu-crosslinked EAMs did not. Gp improves the stability of the EAM while maintaining minimal biological reactivity and preserving EAM epithelial proliferation capacity, yielding a tissue scaffold that may form the basis of a durable and biocompatible tissue-engineered oesophagus.     

Cytokine production following experimental implantation of xenogenic dermal collagen and polypropylene grafts in mice

AIM: We earlier showed that xenogenic Pelvicol (Bard, Olen, Belgium) implants induce a lesser inflammatory response than Prolene (Johnson and Johnson, Dilbeek, Belgium). The purpose of this study was to determine cytokine profiles in the host immune responses to Pelvicol in a mouse model. The hypothesis was that Pelvicol would induce a "T-helper2" (Th2) rather than T-helper1 (Th1) type of inflammatory response. METHODS: Mice were implanted subcutaneously with Pelvicol or Prolene and the graft sites were harvested at 3 to 28 days. Histopathology was done and cytokine levels were determined by immunohistochemistry and RT-PCR. Flow cytometry was used to identify which cell population contributed to the observed cytokine production profiles. RESULTS: Pelvicol induced a decreased inflammation and displayed an increase in IL-10 and TGF-beta, but reduce of TNF-alpha and IFN-gamma, indicating a Th2 type dominated response as examined by immunohistochemistry and RT-PCR. Flow cytometry showed that the monocytes/maceophages were the main cell population responsible for production of these cytokines. Monocytes/maceophages from Pelvicol explants showed upregulated expression of IL-10 while Prolene explants expressed TNF-alpha. CONCLUSION: Pelvicol induced a Th2 type cytokine-dominated immune response after subcutaneous implantation in mice.     

Surface Roughness and Morphology Customization of Additive Manufactured Open Porous Ti6Al4V Structures

Additive manufacturing (AM) is a production method that enables the building of porous structures with a controlled geometry. However, there is a limited control over the final surface of the product. Hence, complementary surface engineering strategies are needed. In this work, design of experiments (DoE) was used to customize post AM surface treatment for 3D selective laser melted Ti6Al4V open porous structures for bone tissue engineering. A two-level three-factor full factorial design was employed to assess the individual and interactive effects of the surface treatment duration and the concentration of the chemical etching solution on the final surface roughness and beam thickness of the treated porous structures. It was observed that the concentration of the surface treatment solution was the most important factor influencing roughness reduction. The designed beam thickness decreased the effectiveness of the surface treatment. In this case study, the optimized processing conditions for AM production and the post-AM surface treatment were defined based on the DoE output and were validated experimentally. This allowed the production of customized 3D porous structures with controlled surface roughness and overall morphological properties, which can assist in more controlled evaluation of the effect of surface roughness on various functional properties.     

Synthesis and Properties of Novel Thermoresponsive Polyesters with Oligo(ethylene glycol) Pendent Chains

A new class of thermoresponsive polyesters is prepared by alternating ring‐opening copolymerization of succinic anhydride (SA) and epoxide bearing oligo(ethylene glycol) (oligo‐EG) pendant chains with the number of repeat ethylene glycol unit ranging from 1 to 3. The copolymerization kinetics and their various properties are investigated in detail. The increase of oligo‐EG length leads to a significant shift of the thermoresponsive transition to higher temperature. The copolymers hydrolyzed with unusual chain end cleavage mode and base acceleration feature. And the copolymers and their degradation products had no acute toxicities. The reported thermoresponsive polyesters are highly useful materials for in vivo biomedical applications.     

Nanobiomaterial applications in orthopedics.

Advancements in nanobiotechnology are revolutionizing our capability to understand biological intricacies and resolve biological and medical problems by developing subtle biomimetic techniques. Nanocomposites and nanostructured materials are believed to play a pivotal role in orthopedic research since bone itself is a typical example of a nanocomposite. This article reviews current strategies using nanobiomaterials to improve current orthopedic materials and examines their applications in bone tissue engineering. Preliminary investigations support the potential of nanobiomaterials in orthopedic applications; however, significant advancements are necessary to achieve clinical use. Overall, current trends in nanobiotechnology foreshadow a bright future through the use of nanobiomaterials in the orthopedic domain.     

女性骨盆重建中医用网片的并发症：腐蚀和挤压

目的：近年来不同的医用移植物越来越多的被用在尿失禁和盆腔器官脱垂疾病的治疗上。自体材料如肌肉和筋膜等被首先用在对盆腔解剖结构的支持。然而，为了尝试减少手术中感染机率，人工合成材料逐渐被应用。但是，合成材料随之带来的并发症，如感染，腐蚀或对周围组织挤压等，这些都是我们急需解决的问题。我们回顾了相关文献，总结了骨盆重建中应用移植物的一些观点，重点关注针对合成材料相关并发症的治疗方面。材料和方法：我们较全面的查阅了在MEDLINE数据库中有关方面的文献和总结了以前这方面回顾性文章的结论。结论：生物材料给我们带来一定的疾病治愈率的同时，也带来了一些潜在的不良因素，包括不同性质和成本的材料所带来的并发症。因此，合成材料在盆腔修复中的选择性应用成为了焦点。在合成材料中，Ⅰ型大孔聚丙烯网片被公认为优越性高和并发症率低的材料。网片的腐蚀和挤压是较常见和麻烦的并发症，既可以采用以观察为主的保守治疗，局部用或不用激素辅助治疗，也可以依靠网片放置部位和型号来选择采用经阴道清创手术或外科探查术，或网片的摘除手术。结论：理想的移植物应具备结构完整性，持续性，低排斥性。总之，生物材料趋向于发生更少的并发症。因此，由于同种异体移植物存在较多的风险，其实用价值和性价比的问题已经引起人工合成物的发展。虽然合成物也有导致腐蚀和压迫的趋势，但这些并发症是能够被很好解决的。