SDF-1α/CXCR4 信号通路在轴向应力刺激促进骨再生中的作用研究

目的通过轴向应力刺激促进骨再生，观察基质细胞衍生因子 1α/趋化因子 CXC 亚族受体 4（stromal cell-derived factor 1α/cysteine X cysteine receptor 4，SDF-1α/CXCR4）信号通路变化，探讨轴向应力刺激促进骨再生的机制。方法取 72 只雄性新西兰大白兔，于右后肢胫骨近端内侧制备直径 8 mm 圆形皮质骨缺损并脱蛋白松质骨支架修复模型，随机分为 3 组（n=24）。A 组腹腔注射 PBS，B 组术肢给予应力刺激治疗+腹腔注射 PBS，C 组术肢给予应力刺激治疗+腹腔注射 CXCR4 拮抗剂（AMD3100）。术后 2、4、8、12 周，摄 X 线片并采用 Lane-Sandhu X 线评分标准评价骨愈合情况，取标本行 HE 染色观察新生骨组织及支架降解，免疫组织化学染色观察 VEGF、CXCR4 表达水平；4、8 周取标本 Western blot 检测 SDF-1α 及 CXCR4 蛋白表达水平；12 周行 Micro-CT 检查，计算新生骨体积及新生骨密度。 结果X 线片检查示，除术后 2 周各组骨缺损区及支架无明显变化外，4、8 及 12 周时 B 组骨愈合评分均高于 A、C 组（P<0.05）。12 周时 Micro-CT 扫描可见 B 组骨缺损修复、髓腔再通，新生骨体积及骨密度均高于 A、C 组（P<0.05）。HE 染色显示，术后 4 周开始 B 组骨再生及支架降解均明显快于 A、C 组。免疫组织化学染色示，各组 VEGF 及 CXCR4 阳性表达均在 4 周达峰值；各时间点 B 组 VEGF 及 CXCR4 表达量均显著高于 A、C 组（P<0.05）。Western blot 检测显示，4、8 周时 B 组 SDF-1α 与 CXCR4 表达量均显著高于 A、C 组（P<0.05）。 结论轴向应力刺激促进骨再生可能与其促进骨缺损区组织高表达 SDF-1α，激活与其下游调控 BMSCs 募集的 CXCR4 信号有关。     

Predictions of genotoxic potential,mode of action,molecular targets,and potency via a tiered multiflow® assay data analysis strategy

The in vitro MultiFlow® DNA Damage Assay multiplexes γH2AX, p53, phospho-histone H3, and polyploidization biomarkers into a single flow cytometric analysis. The current report describes a tiered sequential data analysis strategy based on data generated from exposure of human TK6 cells to a previously described 85 chemical training set and a new pharmaceutical-centric test set (n = 40). In each case, exposure was continuous over a range of closely spaced concentrations, and cell aliquots were removed for analysis following 4 and 24 hr of treatment. The first data analysis step focused on chemicals' genotoxic potential, and for this purpose, we evaluated the performance of a machine learning (ML) ensemble, a rubric that considered fold increases in biomarkers against global evaluation factors (GEFs), and a hybrid strategy that considered ML and GEFs. This first tier further used ML output and/or GEFs to classify genotoxic activity as clastogenic and/or aneugenic. Test set results demonstrated the generalizability of the first tier, with particularly good performance from the ML ensemble: 35/40 (88%) concordance with a priori genotoxicity expectations and 21/24 (88%) agreement with expected mode of action (MoA). A second tier applied unsupervised hierarchical clustering to the biomarker response data, and these analyses were found to group certain chemicals, especially aneugens, according to their molecular targets. Finally, a third tier utilized benchmark dose analyses and MultiFlow biomarker responses to rank genotoxic potency. The relevance of these rankings is supported by the strong agreement found between benchmark dose values derived from MultiFlow biomarkers compared to those generated from parallel in vitro micronucleus analyses. Collectively, the results suggest that a tiered MultiFlow data analysis pipeline is capable of rapidly and effectively identifying genotoxic hazards while providing additional information that is useful for modern risk assessments—MoA, molecular targets, and potency. Environ. Mol. Mutagen. 60:513–533, 2019. © 2019 Wiley Periodicals, Inc.     

Temporal Trends of Women Enrollment in Major Cardiovascular Randomized Clinical Trials

Background

Although it is known that women do not participate in trials as frequently as men, there are limited recent data examining how women recruitment has changed over time.

Dietary fat intake and metabolic syndrome in adults: A systematic review

Background and aimsThe metabolic syndrome (MetS) is a cluster of coexisting cardiovascular risk factors. The role of specific dietary fats was reemphasized by dietary recommendations. This systematic review aims to assess evidence for the effect of dietary fat intake on MetS occurrence and reversion in adults.Methods and ResultsThe MEDLINE database was used to search the existing literature. We included observational studies that analyzed dietary fat intake in adults with MetS and clinical trials that compared the effects of different dietary fat diets on MetS and/or its components. Thirty articles were selected (14 observational and 16 clinical trials), and we included information of dietary fat and fatty acids as well as MetS, body mass index, cholesterol, hypertension, and diabetes in adults. SFA intake was found to be positively associated with MetS components. Most of the observational reviewed studies found beneficial associations between MUFA and PUFA (including n-3 and n-6 subtypes) intake and MetS components. Clinical trials also supported the benefits of MUFA- or PUFA-enriched diets (including low-fat diets) in reducing MetS.ConclusionsThe effects of dietary SFAs on MetS will be influenced by other specific nutrients. Replacement of SFA by MUFA and PUFA has been associated with a decrease in MetS. Dietary recommendations should emphasize on different qualities of fat intake, not only to reduce total fat intake, to obtain health benefits in adults.     

淫羊藿苷对骨微血管内皮细胞自噬及外泌体产生的影响

目的评估淫羊藿苷对低浓度糖皮质激素诱导的骨微血管内皮细胞（bone microvascular endothelial cells，BMECs）自噬和外泌体分泌的影响。方法从行全髋关节置换术切取的股骨头中分离 BMECs，用一系列低浓度梯度氢化可的松（0、0.03、0.06、0.10 mg/mL）干预（设为 A、B、C、D 组），在此基础上再用 5×10⁻⁵ mol/L 淫羊藿苷干预（设为 A1、B1、C1、D1 组），24 h 后采用 Western blot 检测自噬相关蛋白微管相关蛋白轻链 3B（microtubule-associated protein 1 light chain 3B，LC3B）及死骨片 1（p62）的表达。从经淫羊藿苷处理（干预组）和未经淫羊藿苷处理（未干预组）的 BMECs 中提取外泌体，纳米颗粒跟踪分析技术检测其直径和浓度，BCA 法检测外泌体总蛋白质含量，Western blot 检测外泌体 CD9、CD81、TGF-β₁ 和 VEGFA 蛋白的表达。进一步将 BMECs 分为 3 组，实验组和对照组分别分离经或未经淫羊藿苷处理的 BMECs 分泌的外泌体，与 BMECs 共培养；空白对照组为单纯 BMECs。氢化可的松处理后，采用 Western blot 检测 LC3B 和 p62 表达，划痕实验检测细胞迁移能力，并观察血管生成能力。 结果随氢化可的松浓度升高，各组 LC3B-Ⅱ蛋白相对表达量逐渐增加，p62 蛋白相对表达量减少，各组间差异均有统计学意义（P<0.01）；相同激素浓度下，淫羊藿苷干预后，LC3B-Ⅱ蛋白相对表达量减少，p62 蛋白相对表达量增加（P<0.01）。干预组外泌体浓度显著高于未干预组（t=−10.191，P=0.001）；两组外泌体直径和总蛋白质含量比较差异均无统计学意义（P>0.05）。未干预组和干预组 CD9 和 CD81 蛋白均高度表达；干预组 VEGFA/CD9 和 TGF-β₁/CD9 蛋白相对表达量比值均显著高于未干预组（P<0.01）。外泌体共培养后，空白对照组、对照组和实验组中 p62 蛋白相对表达量呈递增趋势，LC3B-Ⅱ蛋白相对表达量呈递减趋势，各组间比较差异均有统计学意义（P<0.05）。氢化可的松处理 12、24 h 时，对照组和实验组划痕闭合率明显高于空白对照组（P<0.05），实验组明显高于对照组（P<0.05）；氢化可的松处理 4、8 h 时，实验组和对照组管腔数、出芽数和小管分支长度均显著大于空白对照组（P<0.05）；实验组小管分支长度和管腔数显著大于对照组（P<0.05）。 结论淫羊藿苷及 BMECs 产生的外泌体能改善低浓度激素诱导的 BMECs 自噬，对内皮细胞起到保护作用。     

Metformin inhibition of mitochondrial ATP and DNA synthesis abrogates NLRP3 inflammasome activation and pulmonary inflammation

1. Download : Download high-res image (269KB)
2. Download : Download full-size image

     

股骨转子间骨折的稳定性重建概念演化与研究进展

目的总结近年来股骨转子间骨折在稳定性重建方面的概念演化与研究进展。方法查阅国内外相关文献并结合自身经验，从股骨转子间骨折的解剖特点、稳定型骨折与不稳定型骨折分类、稳定性复位与不稳定性复位、术中加压初始稳定与术后滑动二次稳定、内固定术后稳定性评估、早期下地站立负重等方面进行总结分析。结果股骨转子间骨折发生于股骨颈干骺端转换区，具有天然的内翻不稳定倾向。骨折复位质量是影响后续内固定物安放的最重要前提因素。判断骨折复位质量有对线和对位两方面，对线采用 Garden 指数；在对位方面，随着皮质对位理念（正性、中性、负性）的提出，特别强调前内侧皮质的相互砥住支撑（解剖、正性），是获得骨折稳定性复位的关键，而不再强调后内侧小转子骨块的作用。术后影像学的稳定性评分为早期下地站立负重提供了量化指标。但术中的前内侧皮质支撑复位，在术后头颈骨块滑动获得二次稳定的过程中，仍有皮质对位丢失现象，需研究其危险因素和防范措施。结论股骨转子间骨折在取得良好对线的基础上，只要获得了前内侧皮质的相互砥住和支撑，并用内固定器械维持住，就获得了术后稳定性。术后稳定性评分优良者，可以安全地早期下地负重、站立行走活动。     

Exercise Intolerance in Patients With Heart Failure: JACC State-of-the-Art Review

Exercise intolerance is the cardinal symptom of heart failure (HF) and is of crucial relevance, because it is associated with a poor quality of life and increased mortality. While impaired cardiac reserve is considered to be central in HF, reduced exercise and functional capacity are the result of key patient characteristics and multisystem dysfunction, including aging, impaired pulmonary reserve, as well as peripheral and respiratory skeletal muscle dysfunction. We herein review the different modalities to quantify exercise intolerance, the pathophysiology of HF, and comorbid conditions as they lead to reductions in exercise and functional capacity, highlighting the fact that distinct causes may coexist and variably contribute to exercise intolerance in patients with HF.