婴幼儿心脏外科的新技术新方向

我国先天性心脏病(congenital heart disese,CHD)发病率高,每年新增病例12万～15万,绝大多数需外科手术.复杂CHD包括法乐四联症、肺动脉闭锁、右室双出口、大动脉错位、左室发育不良、完全肺静脉异位引流、完全心内膜垫缺损、主动脉弓离断、主动脉缩窄等,自然病死率极高(1周内病死率30%,1个月内50%).婴幼儿心脏外科手术难度大,病死率高,但早期治疗效果明显[1].     

去端肽胶原介导小干扰RNA抑制大鼠静脉移植物内膜增生

Objective To evaluate the efficacy of using small interfering RNA targeting TF as a therapy for vein graft failure. Methods External jugular vein to carotid artery interposition vein grafts, which were applied to a low flow condition, were made in 120 Sprague-Dawley rats weighing 260 to 300 g. These rats were randomly divided into 4 groups, 30 rats each group. Group A was atelocollagen-TF Stealth<'TM> Select RNAi group. Group B was atelocollagen-TF Stealth<'TM> RNAi group. Group C was atelocollagen group. Group D was control group. Small interfering RNA mixed with atelocollagen was administrated to the external wall of grafted veins. The TF protein expression of vein gratis was analyzed by Western blot at 1, 3, 7, 14, and 28 d postoperatively, and by immunochemistry at 3 d postoperatively. The proliferation index was determined at 14 d postoperatively. Neointimal hyperplasia was evaluated at 28 d postoperatively. BLOCK-iTTM fluorescent oligo was used to confirm its stability and successful transfer into the vein graft wall at 3 and 7 d postoperatively for another group (n = 12). Results Fluorescence of BLOCK-iT<'TM> fluorescent align could be detected in the graft wall even at 7 d postoperatively. Knockdown of the TF expression was achieved by perivascular application of siRNA using atelocollagen. Compared with control group, the intima thickness at 28 d after grafting was significantly reduced (P ＜ 0.05). This phenomenon was preceded by significant reduction of cell proliferation in siRNA-treated grafts at 14 d postoperatively (P ＜0.05). Conclusion The expression of TF in vein grafts can be effectively inhibited by specific siRNAs using a atelocoilagen-based nonviral delivery approach/n vivo, so that the neointimal thickening can be prevented.     

新型组织工程带瓣管道异种异位移植模型的建立

目的 构建一种操作简便、重复性高的小动物带瓣管道异种异位移植模型.方法 实验组采用四分枝聚乙二醇交联去细胞的SD大鼠肺动脉带瓣管道作为移植物,以端端吻合方式间断缝合于新西兰白兔右颈总动脉,术后第7、14、28天行多普勒超声检查管道通畅情况,28 d后取出管道行石蜡切片形态学检查.对照组大鼠接受假手术.结果 手术成功率实验组96.0％ (24/25),对照组100.0％(20/20),28 d实验组移植管道通畅率87.5％(21/24),对照组吻合口通畅率95.0％(19/20),两组间差异均无统计学意义(P＞0.05),苏木素-伊红(HE)染色可见局部无明显炎症细胞浸润,瓣膜形态、结构完整.结论 此模型操作简便、构建迅速、成功率高,有助于检测组织工程瓣膜在体性能.     

纪念管汉屏教授百年诞辰暨武汉协和心脏大血管疾病国际学术研讨会概要

2014年5月31日＂纪念管汉屏教授百年诞辰暨武汉协和心脏大血管疾病国际学术研讨会＂在华中科技大学同济医学院附属协和医院隆重召开。与会人员包括胡盛寿、朱晓东、石应康、庄建、孙立忠教授等国内顶尖专家,美国、瑞士、泰国等地著名学者,以及来自全国各地的心血管外科专业人员600余名。会议通过讲学、参观、讨论等形式,缅怀我国心胸外科事业的卓越先驱——管汉屏教授,同时对近10年国内外心血管外科领域的新进展、新成就进行深入交流。     

心肝联合移植一例报告

目的 总结原位心肝联合移植1例的诊治体会.方法 2011年11月24日施行了1例原位心肝联合移植,患者原发病为先天性三尖瓣下移畸形、三尖瓣置换术后5年,合并淤血性肝硬化,术前心功能Ⅳ级,肝功能Child Pugh评分为B级.手术采用分次体外循环辅助的方式,先建立腔静脉主动脉转流完成心脏移植,然后建立股静脉-升主动脉转流完成肝移植,最后停机中和.术中主动脉阻断时间为54min,无肝期为38 min,3次体外循环转流时间共计199m in,手术耗时共计517 min.给予巴利昔单抗联合甲泼尼龙免疫诱导治疗,并采用他克莫司+吗替麦考酚酯+泼尼松的方案抗排斥反应,术后加强护肝治疗、抗感染治疗和营养支持治疗.结果 术后第78天受者因多器官功能衰竭而死亡.受者接受呼吸机辅助治疗的时间为78 d,因术后出现低氧血症而接受体外膜肺氧合辅助治疗的时间为63 d.结论 心肝联合移植术是治疗心肝功能衰竭的有效手段,手术前后的管理具有较高要求.     

转化生长因子-β1对天然支架组织工程瓣膜作用

构建组织工程心脏瓣膜（TEHV）关键在体外重建宏观、微观培养环境。我们以去细胞瓣作天然支架，肌成纤维细胞作种子细胞，观察转化生长因子（TGF）-β1对TEHV微环境影响。     

枝化状聚乙二醇交联改善猪去细胞主动脉瓣的力学性能比较

目的 采用不同相对分子质量枝化状聚乙二醇(PEG)交联巯基化的猪去细胞瓣,观察其对去细胞瓣膜力学性能的影响.方法 将25例猪去细胞主动脉瓣随机分为5组:PEG3400组、PEG8000组、PEG12000组、PEG20000组和对照组,常温反应时间4 h.测定残余巯基计算交联效率;静态拉伸实验测定力学性能.结果 4 h交联率依次为92.40%、89.88%、87.87%和87.46%,相对分子质量越小,交联效率越高,PEG3400组与其他各组比较,差异有统计学意义(P＜0.05);力学测试显示,相对分子质量越大,力学强度越高,呈一定的正相关,PEG12000和PEG20000组抗拉强度分别为(3.22±0.41)MPa和(3.19±0.15)MPa,与对照组比较,差异有统计学意义(P＜0.05).结论 相对分子质量12000 Da和20000 Da枝化状聚乙二醇交联可有效改善猪去细胞瓣的力学性能,有望用于构建新型复合的组织工程瓣膜支架材料的研究应用.

Abstract：

Objective Branched polyethylene glycols (PEG) with different molecular weight were cross-linked to the porcine decellularized aortic valve (DAV) and the effects of PEG cross-linking on the mechanical properties were investigated. Methods A total of 25 porcine DAVs were randomly assigned into 5 groups: PEG3400, PEG8000, PEG12000, PEG20000 and control. The reactive time was 4 h at room temperature. The efficiency of crosslinking was calculated by measuring the residual thiol group. The mechanical properties were obtained by static tensile test. Results The efficiency of crosslinking was 92. 40% , 89. 88% , 87. 87% and 87. 46% in PEG3400, PEG8000, PEG12000, PEG20000 groups, respectively. As compared with other groups, the PEG3400 group had significantly greater increase in the crosslinking degree (P ＜ 0. 05). Tensile test showed the tensile strength of PEG12000 and PEG20000 groups was (3. 22 ±0.41) and (3. 19 ±0. 15) MPa, respectively, and significantly different from that in control group (P ＜ 0. 05). The tensile strength and young' s modulus had a positive correlation with the molecular weight of PEG. Conclusion Branched PEG with the molecular weight of 12 000 Da and 20 000 Dacan effectively crosslink to the porcine decellularized aortic valves and improve their mechanical behaviors, and has the potential to be used as the material of fabricating new hybrid scaffold of tissue engineering heart valves.     

枝化状聚乙二醇对牛跟腱Ⅰ型胶原结构与构象稳定性的影响

目的 观察枝化状聚乙二醇对牛跟腱Ⅰ型胶原结构与构象稳定性的影响.方法 以牛跟腱Ⅰ型胶原为原料,以枝化状聚乙二醇为交联剂,在有效交联的前提下,通过测定羟脯氨酸含量观察聚乙二醇交联对胶原酶解稳定性的影响,采用示差扫描量热法(DSC)观察胶原热变性温度,采用圆二色光谱法(CD)观察聚乙二醇对胶原三螺旋构象稳定性的影响.结果 枝化状聚乙二醇交联组24 h降解率为26.79%,而对照组则达97.39%,两者比较差异有统计学意义(P＜0.05).交联组热变性温度为(79.1±1.2)℃,与对照组(68.6±1.9)℃比较,差异有统计学意义(P＜0.05);CD谱测定特征性吸收峰差异无统计学意义(P＞0.05).结论 枝化状聚乙二醇可显著提高其热变形温度和抗酶性分解能力,而对其三螺旋结构与构象无明显不利影响,是较理想的生物高分子交联剂,可有望用于胶原分子的交联改性.

Abstract：

Objective The triple helix of collagen is the basis of its biological function, such as cell adhesion and tissue remodeling. Crosslinking of collagen with chemical agent will improve the biomechanical properties. However, the effects of differernt crosslinking agents on the structure and conformation stability of type Ⅰ collagen are rarely investigated. Methods The branched polyethylene glycol ( PEG)derivative ( MW 12 kD) was used as crosslinking agent, and allowed to react with bovine achilles' s tendon type Ⅰ collagen modified by succinimidylacetylthioacetate (SATA). The ability of resistance of crosslinked collagen to enzymatic degradation was investigated by measuring the release of hydroxyproline, and differential scanning calorimeter ( DSC ) was taken to determine the thermal denaturation temperature. The effect of PEG on the riple helix of collagen was studied by circular dichroism ( CD) . Results The resistance ability of PEG crosslinked collagen was strongly enhanced when compared with that of control group ( P ＜0. 05 ) , and the thermal denaturation temperature was also significantly rised. CD demonstrated that PEG crosslinking did not result in the destruction of the triple helix conformation of type Ⅰ collagen. Conclusion Branched PEG derivative used in this study is a promising polymer crosslinking agent that may be utilized in the modification of type Ⅰ collagen.