A bilayer scaffold prepared from collagen and carboxymethyl cellulose for skin tissue engineering applications

Abstract

Treatment of chronic skin wound such as diabetic ulcers, burns, pressure wounds are challenging problems in the medical area. The aim of this study was to design a bilayer skin equivalent mimicking the natural one to be used as a tissue engineered skin graft for use in the treatments of problematic wounds, and also as a model to be used in research related to skin, such as determination of the efficacy of transdermal bioactive agents on skin cells and treatment of acute skin damages that require immediate response. In this study, the top two layers of the skin were mimicked by producing a multilayer construct combining two different porous polymeric scaffolds: as the dermis layer a sodium carboxymethyl cellulose (NaCMC) hydrogel on which fibroblasts were added, and as the epidermis layer collagen (Coll) or chondroitin sulfate-incorporated collagen (CollCS) on which keratinocytes were added. The bilayer construct was designed to allow cross-talk between the two cell populations in the subsequent layers and achieves paracrine signalling. It had interconnected porosity, high water content, appropriate stability and elastic moduli. Expression of vascular endothelial growth factor (VEGF), basic-fibroblast growth factor (bFGF) and Interleukin 8 (IL-8), and the production of collagen I, collagen III, laminin and transglutaminase supported the attachment and proliferation of cells on both layers of the construct. Attachment and proliferation of fibroblasts on NaCMC were lower compared to performance of keratinocyte on collagen where keratinocytes created a dense and a stratified layer similar to epidermis. The resulting constructs succesfully mimicked in vitro the natural skin tissue. They are promising as grafts for use in the treatment of deep wounds and also as models for the study of the efficacy of bioactive agents on the skin.     

Computational modeling of blast induced whole-body injury: a review

Blast injuries affect millions of lives across the globe due to its traumatic after effects on the brain and the whole body. To date, military grade armour materials are designed to mitigate ballistic and shrapnel attacks but are less effective in resisting blast impacts. In order to improve blast absorption characteristics of armours, the first key step is thoroughly understands the effects of blasts on the human body itself. In the last decade, a plethora of experimental and computational work has been carried out to investigate the mechanics and pathophysiology of Traumatic Brain Injury (TBI). However, very few attempts have been made so far to study the effect of blasts on the various other parts of the body such as the sensory organs (eyes and ears), nervous system, thorax, extremities, internal organs (such as the lungs) and the skeletal system. While an experimental evaluation of blast effects on such physiological systems is difficult, developing finite element (FE) models could allow the recreation of realistic blast scenarios on full scale human models and simulate the effects. The current article reviews the state-of-the-art in computational research in blast induced whole-body injury modelling, which would not only help in identifying the areas in which further research is required, but would also be indispensable for understanding body location specific armour design criteria for improved blast injury mitigation.     

加州理工大学图书馆数据监管需求评估项目的启示和思考

介绍数据监管的内涵，阐述加州州立理工大学图书馆数据监管需求评估项目，分析项目成果，指出该项目对国内图书馆的启示，即开展科研数据服务营销推广、数据监管培训服务、通过合作实现高质量的数据监管服务等。     

淋巴结瘘型气管支气管结核的临床分析

目的探讨淋巴结瘘型气管支气管结核(TBTB,Ⅵ型)好发人群、临床症状、影像学表现、纤支镜下表现及转归。方法分析65例TBTB(Ⅵ型)患者,总结临床症状、影像学表现、纤支镜下的表现及转归。结果 (1)好发于年轻人(20~35岁)(75.3%)。(2)入院前平均病程4月,主要症状为咳嗽、咳痰、发热、胸痛等。(3)影像学表现:肺膨胀不全,肺门影增大,气道软组织影等。(4)好发部位:左上支气管、隆突及双侧主支气管、左下支气管、右上支气管、中叶支气管。结论 (1)TBTB(Ⅵ型)症状、影像学特征不典型。(2)患者需随访纤支镜及胸部CT至气道及纵隔内病变完全吸收后方可停药,以免复发。     

TL1A blocking ameliorates intestinal fibrosis in the T cell transfer model of chronic colitis in mice

Tumor necrosis factor like cytokine 1A (TL1A) is a member of the TNF superfamily. Accumulating evidence demonstrated the importance of TL1A in the pathogenesis of inflammatory bowel disease (IBD) and suggested a potential role of TL1A blocking in IBD therapy. Here we aimed to explore whether the anti-TL1A antibody could ameliorate intestinal inflammation and fibrosis in IBD. A T cell transfer model of chronic colitis was induced by intraperitoneal injection of CD4⁺CD45RB^high naive T cells isolated from either C57BL/6 wild type (WT) mice or LCK-CD2-Tl1a-GFP transgenic (L-Tg) mice into recombinase activating gene-1-deficient (RAG^?/?) mice. The colitis model mice were treated prophylactically or therapeutically with anti-Tl1a antibody or IgG isotype control. Haematoxylin and eosin staining (H&E staining), Masson's trichrome staining (MT staining) and sirius red staining were used to detect histopathological changes in colonic tissue; immunohistochemical staining was used to detect the expressions of collagen I, collagen III, TIMP1, vimentin, α-SMA and TGF-β1/Smad3. Results showed that anti-Tl1a antibody could reduce intestinal inflammation and fibrosis by inhibiting the activation of intestinal fibroblasts and reducing the collagen synthesis in the T cell transfer model of chronic colitis. The mechanism may be related to the inhibition of TGF-1/Smad3 signaling pathway.     

Assessment of Mycoplasma gallisepticum vaccine efficacy in a co-infection challenge model with QX-like infectious bronchitis virus

Mycoplasma gallisepticum (MG) is the primary cause of chronic respiratory disease in poultry. We investigated the protective efficacy of the live-attenuated ts-11 and 6/85 MG vaccines against a local MG strain and, in order to enhance signs and mimic a typical field situation, we co-infected birds with a virulent strain of QX-like infectious bronchitis virus (IBV). Both vaccines showed similar ability to protect infected chickens from clinical signs, although ts-11 performed slightly better. Despite the lower protection against clinical disease, 6/85-vaccinated birds had significantly (P?≤?0.05) lower tracheal lesion scores and mucosal thickness at day 28 post-vaccination (7 days post-challenge [dpc] with MG, 2 dpc IBV) and day 31 post-vaccination (10 dpc MG challenge, 5 dpc IBV) compared to ts-11 vaccinated birds, but these difference was not significant at day 33 (12 dpc MG, 7 dpc IBV). Pathogen infection and replication was assessed by qPCR, and the 6/85 vaccine produced a more significant (P?≤?0.05) reduction in MG replication in the lungs, kidneys and livers but enhanced late replication in bursae and caecal tonsils. In contrast, the ts-11 vaccine had a more pronounced reductive effect on replication in tracheas, air sacs, bursae and heart at days 28 and 31, yet increased replication in lungs. Interestingly, both vaccines provided non-specific protection against IBV challenge. The co-challenge model provided useful data on vaccine efficacy, especially on days 31 and 33, and tracheas, lungs, air sacs, kidneys, liver and caecal tonsils were the best organs to assess.