Tissue-Engineered Vascular Grafts: Emerging Trends and Technologies

Vascular tissue engineering has made prodigious progress in recent years by converging multidisciplinary approaches. Latest technological advancements foster the development of next-generation tissue-engineered vascular grafts (TEVGs) for treating various vasculopathies. While traditional therapeutic methods rely on bypassing the severely damaged vessels with synthetic counterparts with no growth potential, contemporary perspectives focus on biodegradable conduits bestowing an inherent remodeling capability. This review highlights emerging innovative trends and technologies adopted to pragmatically fulfill current scientific needs while improving overall TEVG performance in pre-clinical and clinical settings. A comprehensive overview of various milestones achieved in the past few decades is first summarized, followed by an appraisal of the significant hurdles for clinical translation. The latest techniques to rationally address critical challenges, viz., intimal hyperplasia, thrombosis, constructive graft remodeling, and adequate neo-tissue formation are discussed. Finally, an update on ongoing clinical trials is provided and future perspectives required to persuade TEVGs to become a clinical reality are delineated.     

Creep-resistant dextran-based polyurethane foam as a candidate scaffold for bone tissue engineering: Synthesis,chemico-physical characterization,and in vitro and in vivo biocompatibility

A highly crosslinked composite dextran-based scaffold (named DexFoam) was tailored to overcome specific deficiencies of polymeric and ceramic bone scaffolds and to guarantee a bone-mimicking microenvironment for the proliferation of human mesenchymal stem cells in vitro. The creep resistance for up to 90% compressive stain, the capability to regain the original shape after deformation, and the good thermal stability in both physiological and “body limit” conditions make DexFoam a valid alternative to the currently available bone scaffolds. Histopathological evaluation for host reaction and tissue colonization of DexFoam scaffold, implanted subcutaneously in mice, demonstrated its in vivo biocompatibility and biodegradability.     

少量出血患者使用术中回收式自体输血有效性的随机对照研究

目的　探讨术中回收式自体输血（intraoperative autotransfusion, IAT）能否改善少量出血患者的组织氧合及术后恢复。方法　选择2011年12月至2012年4月在北京协和医院行腰椎后路手术、美国麻醉医师协会（American Society of Anesthesiologists，ASA）分级为Ⅰ~Ⅱ级且预计出血量＜20%血容量的患者，随机分为两组，回输组输注回收自体血，对照组给予等量胶体液。检测两组患者术前、术中及术后血红蛋白（hemoglobin，Hb）、乳酸及脑氧饱和度，随访并比较术后恢复指标，包括体温、不适主诉、切口愈合、下地行走时间及术后住院时间。结果　共38例患者纳入本研究，回输组和对照组各19例。回输组术后0.5 h和术后1 d的Hb均高于术中水平［分别为（116.5±10.7）、（115.4±12.3）、（106.6±12.6）g/L；P=0.001，P=0.004］，而对照组术后Hb与术中比较差异无统计学意义（P＞0.05）。对照组术后0.5 h乳酸高于术前［（2.5±1.0）mmol/L比（1.3±0.6）mmol/L，P=0.016］，而回输组术后乳酸与术前比较差异无统计学意义（P＞0.05）。术后Hb、乳酸及脑氧饱和度两组间差异均无统计学意义（P＞0.05）。两组术后恢复指标差异亦均无统计学意义（P＞0.05）。结论　在健康成人患者少量出血手术中使用IAT，对术后早期组织氧合有一定改善作用，但对术后恢复无显著影响。     

Effect of pH,temperature and storage time on the stability of bovine myelin basic protein

Bovine central nervous system tissue (CNT) harboring highest levels of the infectious agent for prion diseases, has been banned from food and feed supplies. Effective detection of CNT in excessively processed meat and feedstuffs requires the assay based on a stable marker in CNT as the analyte. Myelin basic protein (MBP), the major central nervous system (CNS) myelin protein, was reported to be detectable up to 115 °C in the literature. This study further investigated the effects of pH, temperature and storage time on the stability of purified bovine MBP (18.5 kDa) in solutions. Purified MBP dissolved in 10 mM PBS was adjusted to pH 3.0, 7.2 and 10.5, respectively. Sample at each pH was subjected to three heat treatments, 100 °C, 121 °C, and 133 °C for 30 min. The unheated and 100 °C heated samples at pH 7.2 were stored at 4 °C for 19 days to study the storage stability of bovine MBP. The immunoreactivity of all samples was examined using indirect non-competitive enzyme-linked immunosorbent assay and immunoblotting with an anti-MBP monoclonal antibody. The protein degradation was observed by analyzing samples using SDS-PAGE. Results show that bovine MBP was most stable at pH 7.2 while the protein was least stable at pH 10.5. MBP started to degrade after heating at 121 °C for 30 min at pH 7.2. Storage up to 19 days at 4 °C did not significantly affect the immunoreactivity of unheated and heated samples. However, unheated MBP samples started to show degradation from day 8 of storage; while no degradation was observed in 100 °C heated samples over the storage time. This study demonstrated that bovine MBP can be a suitable marker for the detection of bovine CNT in highly processed food and feed supplies.     

Sex and Depot Differences in Palmitoleic Acid Content of Human Blood and Fat

Palmitoleic acid has been classified as an insulin-sensitizing lipokine, but evidence for this from human studies has been inconsistent. We hypothesized that this is related to either the types of samples or conditions under which samples are collected. We measured plasma palmitoleic acid and total free fatty acids (FFA) using ultra-performance liquid chromatography in blood samples collected from 34 adults under a variety of conditions. We collected duplicate samples of adipose (n = 10), FFA (n = 9), and very low density lipoprotein triacylglycerol (VLDL-TAG) (n = 7) to measure the palmitoleic acid as a percentage of total fatty acids. We tested whether the percentage of palmitoleic acid was correlated with insulin resistance, as measured by homeostatic model of insulin resistance (HOMA-IR). Adipose stearoyl-coenzyme A desaturase 1 (SCD-1) protein was measured by capillary Western blotting. FFA-palmitoleic acid percentage increased as a function of total FFA and was greater (p < 0.005) in females than males. Adipose palmitoleic acid percentage was greater in females than males (p < 0.001), as was adipose SCD-1. Palmitoleic acid was greater in femoral fat than in abdominal fat in both females and males (p < 0.001), and correlated positively with HOMA-IR only in females. The test–retest reliability values for percentage palmitoleic acid were 7 ± 10% for adipose, 24 ± 26% for VLDL, and 53 ± 31% for FFA. Because FFA-palmitoleic acid percentage varies as a function of total FFA, investigators should re-evaluate how palmitoleic acid data is presented. The positive relationship between adipose palmitoleic acid and HOMA-IR in females suggests that it is not a potent insulin-sensitizing lipokine in humans.     

Comparison of additive effects on the PVA/starch cryogels: Synthesis,characterization, cytotoxicity,and genotoxicity studies

The research goal of this study is to produce suitable scaffolds for tissue engineering applications. Different ratios of polyvinyl alcohol (PVA)/starch (90:10, 70:30, 50:50) and crosslinking methods have been used to prepare cryogels. Chemically crosslinked cryogels were synthesized using glutaraldehyde as the crosslinking agent. For the physically crosslinked cryogels, sodium dodecyl sulfate was used during cryogelation as the foaming agent. Chemical structure and pore morphology were demonstrated by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Swelling ratio and degradation profile of the scaffolds were also determined. 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide assay and SEM were used to investigate the biocompatibility of the scaffolds and cell morphology. Genotoxicity test was performed to show DNA fragmentation. The overall results demonstrated that PVA/starch cryogels could have potentially appealing application as scaffolds for tissue engineering applications and additives affect the architecture and characteristic properties of the cryogels.     

Core–Sheath Wet Electrospinning of Nanoporous Polycaprolactone Microtubes to Mimic Fenestrated Capillaries

Formation of capillary vessel structures in scaffolds is critical for engineering various tissues and organs. Various biofabrication techniques are developed in recent years to create scaffolds integrated with perfusion channels. However, rapid fabrication of artificial capillary vessels (<10 µm) still remains challenging. In this study, a novel electrospinning approach is developed to fabricate nanoporous polycaprolactone microtubes as potential functional capillaries. The results show that ambient environment parameters and solution properties affect the pore formation and tube morphology. Porous microbeads, helical fibers, and microtubes were fabricated under different processing conditions. The optimal tubular structure is obtained with consistent viscosities between the core and the sheath solutions. The biomimetic nanoporous microtubes hold great potential for vascularization in tissue engineering.     

2014~2018年福建省生产领域纸巾纸荧光物质质量分析

对福建省生产领域近五年的纸巾纸进行随机抽样和质量分析,检测了产品的可迁移性荧光物质指标。结果显示:纸巾纸产品的可迁移性荧光物质指标共出现5批次不合格产品,产品合格率为98.7%,呈现较高的质量水平;纸巾纸的荧光物质检出率近五年呈现先上升后下降的趋势,2015年出现检出率峰值,其值为15.0%,2018年降为0%。按地域统计,福州地区出现3批次可迁移性荧光物质的纸巾纸产品,产品合格率为95.2%;其余地市的产品合格率均为100%。同时,福州纸巾纸产品荧光物质检出率最高,检出率达到12.7%。按产品质量等级统计,纸巾纸优等品的产品质量总体高于合格品的。