出血性蛇毒诱导血管内皮细胞凋亡的成分及作用机制研究进展

出血性蛇毒能专一性诱导血管内皮细胞(vascular endothelial cells，VEC)凋亡，研究人员已从中分离出5种VEC凋亡诱导成份，其中2种为L—aa氧化酶类，3种属于金属蛋白酶／解整联蛋白家族。研究证实前者可通过氧化VEC细胞膜上的L—leu产生H2O2而诱导其凋亡，后者则通过干扰膜整联蛋白与其配体的结合而使VEC凋亡。在由蛇毒诱导的VEC凋亡过程中，p53和bcl-2基因表达增加，且bcl-2的mRNA被剪辑成2条。已证实锚定依赖性信号分子αvβ3和磷脂信号分子PC-PLC参与该过程的信号转导。对该领域进一步研究，有望从蛇毒中纯化出或人工构建出专一地诱导肿瘤血管细胞凋亡的成分。本文总结了出血性蛇毒方面的研究进展。     

Human CD4+CD25+ Regulatory T Cells Suppress Anti-Porcine Xenogeneic Responses

Due to the shortage of human organs, xenotransplantation is being explored as an alternative to allotransplantation, but immune rejection remains a major hurdle to its implementation. We tested the ability of human CD4+CD25+ T cells (Treg cells) to suppress CD4+ T cell-mediated anti-porcine xenoresponses usingin vitroassays. Human Treg cells were hyporesponsive to porcine cell stimulation and suppressed the proliferative response of CD4+CD25- T cells in a dose-dependent manner, and comparison of the allo- and xenoresponses indicated that more Treg cells might be required to suppress the xenogeneic response than the allogeneic response. Stimulation of CD4+CD25- T cells with porcine cells resulted in secretion of IFN-gamma, TNF-alpha, IL-10, IL-6 and IL-2, and Treg cells suppressed the secretion of these cytokines, as well as the CD4+CD25- T-cell cytolytic response against porcine cells. These results suggest a potential role for Treg cells in promoting xenograft survival.     

快速富集骨髓干细胞复合羟基磷灰石三钙在胸腰椎骨折中的应用

胸腰椎骨折在临床上是脊柱骨折的好发部位,后路手术多采用椎弓根钉系统复位固定加椎板间或横突间植骨融合。后外侧融合是降低内固定失败、减少纠正丢失等并发症的有效措施。传统植骨采用自体髂骨,也有运用同种异体骨,但有一定并发症发生率。近年来有单纯运用骨髓移植治疗骨缺损     

雷帕霉素对炎性反应状态下肾小球系膜细胞内脂质稳态的影响

Objective To investigate the effect of rapamycin on cholesterol homeostasis of glomerular mesangial cells and the underlying mechanism. Methods Glomerular mesangial cell line (HMCL) cells were cultured and divided into control group, IL-1β group and different concentration rapamycin groups. Intracellular cholesterol accumulation was observed and measured by oil O staining and HPLC. Real-time quantitative PCR and Western blot were used to detect the mRNA and protein expression of LDLR, PPARγ, LXRα, ABCA1 in HMCL after the treatment with IL-1β and rapamycin. Results Rapamycin had no significant influence on intracellular cholesterol concentration under normal condition. IL-1β significantly increased the intracellular cholesterol concentration by 143％ of control (P<0.05), and 10, 50, 100 ?滋g/L rapamycin could significantly inhibit the effect of IL-1β (87％, 116％, 96％ of control respectively, all P<0.05). Rapamycin could suppress the increased expression of LDLR caused by IL-1β on both mRNA and protein level in a dose-dependent manner（P<0.01）. Rapamycin dose-dependently up-regulated the reduced mRNA and protein expression of ABCA1, the decreased mRNA expression of PPARγ and LXRα induced by IL-1β as well (P<0.01）. Conclusion Rapamycin may contribute to the maintenance of intracellular cholesterol homeostasis in glomerular mesangial cells under inflammatory state by both reducing cholesterol uptake and promoting cholesterol efflux.     

脂肪干细胞/Ⅰ型胶原凝胶复合体的构建及其体内外成骨分化研究

目的探讨利用脂肪干细胞与Ⅰ型胶原凝胶复合构建新型骨组织工程复合体的可行性并对其体内外成骨分化情况进行分析。方法取3月龄日本大耳白兔肩胛部皮下脂肪，Ⅰ型胶原酶消化获得细胞，于体外依次进行骨、软骨、脂肪多向诱导分化鉴定；取第3代细胞与Ⅰ型胶原凝胶复合，于成骨诱导条件下体外培养，相差显微镜、扫描电镜观察复合情况并对其碱性磷酸酶、细胞外基质矿化程度进行检测，同时设立单层贴壁培养细胞作为对照（n=4）；两周后移植于裸鼠皮下，12周后处死动物，依次行放射学、组织学检测观察成骨情况（n=3）。结果（1）所获细胞具备骨、软骨、脂肪多向分化潜能，为多能干细胞。（2）形态学观察显示脂肪干细胞呈三维立体生长状态，均匀、高密度悬浮于Ⅰ型胶原凝胶中。在体外成骨诱导条件下，其碱性磷酸酶活性以及外基质矿化程度均显著高于单层贴壁培养细胞（P〈0．01，n=4）。（3）于裸鼠皮下移植12周后，放射学、组织学检测显示脂肪干细胞．Ⅰ型胶原凝胶复合体成骨明显（n=3）。结论（1）IⅠ型胶原凝胶可显著促进脂肪干细胞的成骨分化。（2）作为一种新型的骨组织工程复合物，脂肪干细胞-Ⅰ型胶原凝胶复合体可应用于骨组织工程，特别是腔隙性骨缺损的修复过程。     

骨髓间充质干细胞促进骨-肌腱结合部愈合的初步观察

[目的]观察骨髓间充质干细胞对骨-肌腱结合部愈合的影响.[方法]采用骨髓穿刺、全骨髓培养法获取兔骨髓间充质干细胞.36只18周龄新西兰大白兔随机分为2组,实验组将骨髓间充质干细胞与Pluronic F-127载体材料结合后,植入兔髌骨部分切除模型,对照组只进行手术,不植入细胞.在术后6、12、18周进行X线片、大体和组织学观察评估.[结果]X线片显示术后6、12、18周实验组骨-肌腱结合部新生骨面积显著大于对照组（P＜0.01）.大体观察可见实验组骨-腱结合部愈合较早.HE染色显示实验组术后6周有大量的纤维母细胞和类软骨细胞增生,并可见新骨形成;12周,髌腱与松质骨接触面软骨细胞移行带形成;18周,纤维软骨移行带排列更有序.Safranin 0染色显示实验组术后6周,基质染色较深,部分骨-腱结合处可见相对浓染区;12周,基质染色范围明显减少,沿类软骨细胞走行分布;18周,类软骨细胞集中的区域染色较12周有所减退.组织学检查显示实验组术后6、12、18周骨-腱结合部组织愈合明显,较对照组迅速.[结论]骨髓间充质干细胞可以促进骨-肌腱结合部细胞增生,促进其早期愈合.     

RGD-based strategies for selective delivery of therapeutics and imaging agents to the tumour vasculature

During the past decade, RGD-peptides have become a popular tool for the targeting of drugs and imaging agents to alphavbeta3-integrin expressing tumour vasculature. RGD-peptides have been introduced by recombinant means into therapeutic proteins and viruses. Chemical means have been applied to couple RGD-peptides and RGD-mimetics to liposomes, polymers, peptides, small molecule drugs and radiotracers. Some of these products show impressive results in preclinical animal models and a RGD targeted radiotracer has already successfully been tested in humans for the visualization of alphavbeta3-integrin, which demonstrates the feasibility of this approach. This review will summarize the structural requirements for RGD-peptides and RGD-mimetics as ligands for alphavbeta3. We will show how they have been introduced in the various types of constructs by chemical and recombinant techniques. The importance of multivalent RGD-constructs for high affinity binding and internalization will be highlighted. Furthermore the in vitro and in vivo efficacy of RGD-targeted therapeutics and diagnostics reported in recent years will be reviewed.     

生长板软骨细胞促进骨髓基质干细胞血管内皮生长因子的表达

目的观察骨髓基质干细胞(BMSCs)在生长板软骨细胞旁分泌作用下血管内皮生长因子(VEGF)的表达规律及其与成骨分化的相关性。方法大鼠BMSCs与生长板软骨细胞进行间接共培养,培养终末期做细胞化学染色,定量测定碱性磷酸酶(ALP)活性,用RT-PCR方法半定量检测VEGFmRNA的表达。结果生长板软骨细胞持续高表达VEGF。BMSCs随共培养时间的延长,ALP活性升高,BMSCs的VEGF的表达也逐渐增强。培养液加入两种分泌型VEGF中和抗体后,VEGF表达趋势不变,ALP活性仍为升高趋势,也不影响培养终末期钙化结节的形成。培养终末期BMSCs的CD31和CD34均阴性。结论BMSCs成骨分化过程中VEGF的表达符合成骨细胞分化基因的表达规律,与成骨细胞特征性基因的表达趋势一致,体外条件共培养条件下,中和VEGF后并不能阻碍BMSCs的成骨分化。     

肿瘤干细胞与肝癌干细胞

肿瘤起源于干细胞的假说正在各种人类肿瘤中得到证实,肿瘤不单是一种基因病,而且是一种干细胞病,基因突变作用于干细胞,干细胞突变成为肿瘤干细胞,这是肿瘤发生、再生、转移和复发的关键。肝细胞癌是最常见的恶性肿瘤之一,其中是否存在“肝癌干细胞”的问题一直倍受人们关注。该文介绍肿瘤干细胞与肝癌干细胞的研究情况。     

骨髓间充质细胞与速固化磷酸钙支架共培养的实验研究

[目的]观察人骨髓间充质干细胞在速固化磷酸钙骨水泥支架中的增殖和生长情况。[方法]将速固化壳聚糖-磷酸钙骨水泥支架材料预先成形。采用全骨髓法分离人骨髓间充质细胞并在体外对细胞进行培养和扩增。72h首次换液,细胞融合80%传代,取第3代细胞用于实验。将细胞与磷酸钙骨水泥支架复合培养,分别利用四甲基偶氮唑蓝MTT法及扫描电镜等检测细胞在材料中的增殖和生长情况。[结果]用酶标仪检测OD值提示共培养后,支架内的细胞数量逐渐增加。扫描电镜结果显示支架材料内部为多孔结构,孔内见有细胞生长,细胞表面可见分泌颗粒。[结论]速固化壳聚糖-磷酸钙骨水泥对人骨髓间充质干细胞有较好的细胞相容性,细胞可在材料内黏附和增殖,是理想的骨组织工程支架材料。