This study is supported by the Dutch Heart Foundation and the Netherlands Institute for Regenerative Medicine.

该协议遵循动物研究伦理委员会的LUMC准则。 1.准备仪器，培养基和MTCS 注：请在层流罩的所有准备工作。该MTCS灌注腔，泡沫陷阱，站在利伯等人 ，2010 11描述。 <ol><li>消毒镊子和微型剪刀用70％的乙醇。制备一个5毫升注射器用21G针用无菌台氏缓冲液（130毫摩尔NaCl，5.4毫米氯化钾，6.0毫摩尔的Hepes，1.2mM的MgSO 4干燥，1.2mM的磷酸二氢钾 ，20mM的葡萄糖，1.5mM的氯化钙 2·2H 2 O， pH值= 7.2）。制备一个5毫升注射器用21G针用无菌KCl溶液（100毫摩尔）。 </li><li>制备65毫升每心脏培养基：DMEM补充有10％胎牛血清，抗生素/抗真菌剂（A / A; 100单位的青霉素，100微克的链霉素和0.25微克两性霉素B / ml）的胰岛素转铁硒（ITS; 10微克/毫升的胰岛素，5.5微克/毫升运铁蛋白，6.7纳克/毫升亚硒酸钠）和过滤杀菌。 </li><li>通过用70％乙醇和干燥用纸巾喷洒消毒灌注腔和气泡阱。然而组装MTCS（图1D），最初没有灌注腔。放置在支架上的泡沫陷阱。使用蠕动滚子泵具有易于装载泵头。 <ol><li>使用硅管使（见图1D）的贮存器（50毫升管）和泵，泵和气泡阱，所述气泡收集器和储存器之间的连接。使培养箱足够长内的管道，以允许介质达到平衡气体与气体在通过气体可渗透的硅管（1米）和培养箱尽可能短外管培养箱。 </li></ol></li><li>填充50ml管中，用70％的乙醇，开启泵（流速约1毫升/分钟，以允许适当的循环），并让乙醇CIRculate 30分钟进行消毒所有管道。通过清空贮存器和泵出从系统中的乙醇除去乙醇。 </li><li>填充50ml管中，用无菌蒸馏水，开启泵和让水循环30分钟，以除掉剩余的乙醇。通过清空容器和从系统中抽出的水除去水。 </li><li>填充50毫升管45毫升培养基，将支架在孵化器。开启泵（约1毫升/分钟流速）和分发介质填满所有管道，除去所有气泡，并允许介质相适应的气体组合物在孵化器至少1小时。保持培养箱中的标准组织培养条件下（5％CO 2和37℃）。确保没有气泡存在于管中。 </li></ol> 2.隔离小鼠心脏的<ol><li>注入鼠标500单位肝素。这将防止血液凝固和允许移除的Blood从心脏。 10分钟后，麻醉小鼠的感应室使用精密汽化器4％异氟烷。麻醉是足够的，当鼠标不响应脚趾捏。 </li><li>传输鼠标到夹层板和连接到同轴电路面罩来维持麻醉。消毒鼠标用70％酒精的皮毛。用剪刀打开腹腔，以暴露腔静脉和隔膜。 </li><li>暴露心脏，使开始从最后到第一肋外侧切口，反映胸廓过老鼠的头部。停止麻醉鼠标没有呼吸了。观察心脏的跳动。 </li><li>插入21G针连接到一个5毫升注射器含有无菌蒂罗德缓冲到从腹部下腔静脉进入胸腔（通过隔膜）。确保血液可从针头插入腔静脉尾退出。灌注日Ë台氏缓冲轻轻恒压进入腔静脉，直到心脏部分失去了它的红色。注：心脏跳动仍然允许去除血液从心脏。 </li><li>替换与连接到一个5毫升注射器含有无菌KCl溶液的21G针的针。轻轻灌注KCl溶液放入腔静脉，直到心脏停止跳动，取出针。注意：KCl溶液保留心脏处于松弛舒张阶段，这将允许灌注针更容易地插入冠状动脉系统和灌注。 </li><li>略使用弯钳解除心脏和用剪刀解剖心脏不受周围的组织，但留下的动脉和静脉的近端到心脏的完整和附连到心脏。在心脏转移到15毫升管含冰冷的PBS辅以抗生素/抗真菌剂（A / A）。存储在冰冷的PBS的心脏长达3小时。 </li></ol> 3. Cannulation中的小鼠心脏中灌注腔<ol><li>请在层流罩的所有程序。从15ml试管转移离体心脏到10cm培养皿，并添加PBS辅以A / A。 </li><li>在解剖显微镜下，使用微剪刀和镊子以除去所有非心脏组织，但保留在升主动脉，以至少与头臂动脉和肺静脉，2毫米近端心脏分叉。切断心脏顶点的尖端创造进入左心室腔内（通常为2毫米）。将灌注腔中的解剖显微镜下的流罩。 </li><li>附加一个5毫升注射器用培养基使用硅胶管插入针。填充灌注腔用20ml培养基并把心脏上的旋转台在灌注腔2的钝化针晶（ 图1）之间。调节旋转台的高度，使心脏的定位在前面针。 </li></ol> 4.结扎用于培养的二尖瓣（参见图1） <ol><li>结扎用缝合（丝7.0）主动脉。结扎左心耳与缝合。插入针（NR 1中图1）通过肺静脉进入左心房，并与缝合线近端结扎到其在左心房入口。确保针头不太远进入左心房，因为这会损害二尖瓣。 </li><li>插入针（nr.2 于图1）与直线运动到左心室。从灌注腔转移介质到50ml管。密封针与生物相容性胶心肌。 </li><li>之后胶水已干，小心地连接介质填充注射器针头nr.1，并检查是否有泄漏注入介质插入心脏。确保从针nr.2最后剩余的血液灌注出来的心脏该介质退出。 </li></ol> 5.李gation用于培养的主动脉瓣（见图1） <ol><li>插入在主动脉针（nr.1 在图1中），并结扎用缝合。确保针头不太远进入主动脉，因为这会损害主动脉瓣。插入针（nr.2 于图1）与直线运动到左心室。从灌注腔转移介质到50ml管。密封针与生物相容性胶心肌。 </li><li>之后胶水已干，小心地连接介质填充注射器针头nr.2，并检查是否有泄漏注入介质插入心脏。确保从针nr.1最后剩余的血液灌注出来的心脏该介质退出。 </li></ol> 6.将灌注腔上立场<ol><li>填补了灌注腔与传输介质20毫升将垫片和盖子上腔和拧紧垫圈和螺丝。 </li><li>从incuba取下组装MTCS器。附加灌注腔上的立场。连接管（参见图1D）。将立在培养箱（5％CO 2和37℃）。将管线连接到泵上。打开与约600μl/ min的流速泵。 </li><li>确保在储存和/或气泡阱介质的级别允许流的存在下的可视化由落入传入介质滴。培养后，心脏被从系统中移除，固定和处理以用于组织学检查。 </li></ol>

<ol>
	<li>Go, A. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+Disease+and+Stroke+Statistics--2014+Update:+A+Report+From+the+American+Heart+Association.">Heart Disease and Stroke Statistics--2014 Update: A Report From the American Heart Association.</a> Circulation. 129, e28-e292 (2013).</li><li>Gould, S. T., Srigunapalan, S., Simmons, C. A., Anseth, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamic+and+Cellular+Response+Feedback+in+Calcific+Aortic+Valve+Disease.">Hemodynamic and Cellular Response Feedback in Calcific Aortic Valve Disease.</a> Circulation Research. 113 (2), 186-197 (2013).</li><li>Kruithof, B. P. T., Krawitz, S. A., Gaussin, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atrioventricular+valve+development+during+late+embryonic+and+postnatal+stages+involves+condensation+and+extracellular+matrix+remodeling.">Atrioventricular valve development during late embryonic and postnatal stages involves condensation and extracellular matrix remodeling.</a> Developmental biology. 302 (1), 208-217 (2007).</li><li>Schoen, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+valves+and+valvular+pathology:+update+on+function,+disease,+repair,+and+replacement.">Cardiac valves and valvular pathology: update on function, disease, repair, and replacement.</a> Cardiovascular pathology: the official journal of the Society for Cardiovascular Pathology. 14 (4), 189-194 (2005).</li><li>Balachandran, K., Sucosky, P., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamics+and+mechanobiology+of+aortic+valve+inflammation+and+calcification.">Hemodynamics and mechanobiology of aortic valve inflammation and calcification.</a> International journal of inflammation. , 263870 (2011).</li><li>Butcher, J. T., Simmons, C. A., Warnock, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanobiology+of+the+Aortic+Heart+Valve.">Mechanobiology of the Aortic Heart Valve.</a> The Journal of heart valve disease. 17 (1), 62-73 (2008).</li><li>Balachandran, K., Konduri, S., Sucosky, P., Jo, H., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+ex+vivo+study+of+the+biological+properties+of+porcine+aortic+valves+in+response+to+circumferential+cyclic+stretch.">An ex vivo study of the biological properties of porcine aortic valves in response to circumferential cyclic stretch.</a> Annals of biomedical engineering. 34 (11), 1655-1665 (2006).</li><li>Weiler, M., Hwai Yap, C., Balachandran, K., Padala, M., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+analysis+of+dynamic+deformation+characteristics+of+native+aortic+valve+leaflets.">Regional analysis of dynamic deformation characteristics of native aortic valve leaflets.</a> Journal of Biomechanics. 44, 1459-1465 (2011).</li><li>Combs, M. D., Yutzey, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+valve+development:+Regulatory+networks+in+development+and+disease.">Heart valve development: Regulatory networks in development and disease.</a> Circulation Research. 105, 408-421 (2009).</li><li>Kruithof, B. P. T., Duim, S. N., Moerkamp, A. T., Goumans, M. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGF&#946;+and+BMP+signaling+in+cardiac+cushion+formation:+lessons+from+mice+and+chicken.">TGF&#946; and BMP signaling in cardiac cushion formation: lessons from mice and chicken.</a> Differentiation; research in biological diversity. 84 (1), 89-102 (2012).</li><li>Lieber, S. C., Kruithof, B. P. T., Aubry, N., Vatner, S. F., Gaussin, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+a+miniature+tissue+culture+system+to+culture+mouse+heart+valves.">Design of a miniature tissue culture system to culture mouse heart valves.</a> Annals of biomedical engineering. 38 (3), 674-682 (2010).</li></ol>

The authors declare no conflicts of interest.

在培养该心脏小鼠阀关键步骤包括使来自鼠标切除心脏的和结扎在灌注腔尽可能短，以确保在垂直于阀的可行性的针和结扎之间的时间，以确保流动的正确方向。此外，检查在灌注腔结扎后的流量不中确保适当的插入和针结扎。关键是要保持无菌培养和防止气泡在油管，这有可能被困在心脏阻碍的流动。 用于心脏的灌注介质的总体积是45毫升（注意，即通过心脏灌注介质是不...

心脏瓣膜疾病是发病率和死亡率在西方世界的一个主要原因;其患病率随着年龄的增加，它会影响人口75年的10％以上和更老1。心脏的全身性部分的阀门，主动脉和二尖瓣，大多是受影响的。心脏瓣膜病的特征是所述阀的高度组织的结构，这导致的机械性能2变更的损失。结构完整性，因此对阀的功能是至关重要的。 所述瓣膜的瓣叶被包括瓣膜间质细胞（VIC），瓣膜内皮细胞（VEC），和细胞外基质，这是高度组织在一个分层图案3,4的。所述的VIC负责对ECM合成，降解和组织。因素从血液，内皮细胞发出或居住在编排上其功能的VIC的ECM行为。此外，机械力造成层流或振荡剪切应力，影响的VIC 5的行为压缩或拉伸应力在心动周期中作用于单张。 为了理解如何在阀的结构被调整，首先必须理解的VIC到心脏周期期间所经历的刺激的多样化如何作出反应。 在体外研究已经非常翔实有关瓣膜细胞的特征和能力。这些细胞在体外的反应，但是，可能不总是精确地模仿体内响应6;例如，VIC的对刺激的响应是依赖于内皮的存在和ECM 组合物5。此外，瓣膜细胞对刺激的响应取决于其特定的位置，在小叶7。除了生化刺激，瓣膜细胞的行为是通过作用Ø机械力确定n个阀 8。阀的各区域进行其自己的特定的一组血液动力学应力。尽管目前的体外模型表明，机械力的作用是瓣膜结构 5的重要决定因素，相关的机制仍不清楚。虽然体内模型提供了深入了解潜在的心脏瓣膜发展9,10的分子机制，见解成人瓣膜生物学仍然是难以捉摸的。 因此，开发了离体的流动的模型，其中该心脏瓣膜可以在其在心脏中自然位置的时间11长时间进行培养。这具有的优点是，阀保持在其天然构型和的VIC经历相同的环境作为体内，使得的VIC响应的刺激尽可能自然。此外，阀门在其自然位置在心脏的文化有利于使各瓣膜区域相关的血液动力学应力。在此体外模型，也就是说，微型组织培养系统（MTCS），所述阀可进行不同的生物化学和血液动力学刺激允许其在心脏瓣膜重塑作用的调查。

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle Medium</td>
			<td>life technolgies</td>
			<td>10569-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>life technolgies</td>
			<td>26140</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin-Transferrin-Selenium</td>
			<td>life technolgies</td>
			<td>41400-045</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibiotic-Antimycotic</td>
			<td>life technolgies</td>
			<td>15240-06</td>
			<td></td>
		</tr>
		<tr>
			<td>Silk 7-0</td>
			<td>Ethicon</td>
			<td>768G</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mm culture dish</td>
			<td>Greiner bio-one</td>
			<td>664160</td>
			<td></td>
		</tr>
		<tr>
			<td>50 ml tube</td>
			<td>Greiner bio-one</td>
			<td>227261</td>
			<td></td>
		</tr>
		<tr>
			<td>5 ml syringe</td>
			<td>BD</td>
			<td>309649</td>
			<td></td>
		</tr>
		<tr>
			<td>21 G needle</td>
			<td>BD</td>
			<td>304432</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin</td>
			<td>LEO</td>
			<td>012866-08</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Fine Science Tools</td>
			<td>11295-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Scissors, Economy, Vannas-type</td>
			<td>Tedpella</td>
			<td>1346</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon tubing</td>
			<td>Thermo Scientific</td>
			<td>8060-0020</td>
			<td>I.D. x O.D. x Wall: 1.59 x 3.18 x 0.79 mm</td>
		</tr>
		<tr>
			<td>Silicon tubing for pump</td>
			<td>Masterflex</td>
			<td>96400-13</td>
			<td>I.D. x O.D. x Wall: 0,8 x1,59 x 0,40 mm</td>
		</tr>
		<tr>
			<td>Biocompatible glue (Histoacryl)</td>
			<td>B. Braun</td>
			<td>1050071</td>
			<td></td>
		</tr>
		<tr>
			<td>precision vaporizer</td>
			<td>Dr&#228;ger</td>
			<td>Vapor 200</td>
			<td></td>
		</tr>
		<tr>
			<td>peristaltic roller pump</td>
			<td>Masterflex</td>
			<td>7521-35</td>
			<td></td>
		</tr>
		<tr>
			<td>Easy-load pump head</td>
			<td>Masterflex</td>
			<td>7518-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow chamber</td>
			<td></td>
			<td></td>
			<td>see Lieber et al., 2010</td>
		</tr>
		<tr>
			<td>Bubble trap</td>
			<td></td>
			<td></td>
			<td>see Lieber et al., 2010</td>
		</tr>
	</tbody>
</table>

culturing mouse cardiac valves in the miniature tissue culture system

Heart valve disease is a major burden in the Western world and no effective treatment is available. This is mainly due to a lack of knowledge of the molecular, cellular and mechanical mechanisms underlying the maintenance and/or loss of the valvular structure. 
Current models used to study valvular biology include in vitro cultures of valvular endothelial and interstitial cells. Although, in vitro culturing models provide both cellular and molecular mechanisms, the mechanisms involved in the 3D-organization of the valve remain unclear. While in vivo models have provided insight into the molecular mechanisms underlying valvular development, insight into adult valvular biology is still elusive. 
In order to be able to study the regulation of the valvular 3D-organization on tissue, cellular and molecular levels, we have developed the Miniature Tissue Culture System. In this ex vivo flow model the mitral or the aortic valve is cultured in its natural position in the heart. The natural configuration and composition of the leaflet are maintained allowing the most natural response of the valvular cells to stimuli. The valves remain viable and are responsive to changing environmental conditions. This MTCS may provide advantages on studying questions including but not limited to, how does the 3D organization affect valvular biology, what factors affect 3D organization of the valve, and which network of signaling pathways regulates the 3D organization of the valve.

主动脉瓣（图2）或二尖瓣11可以是培养至少3天。通过在打开位置（其代表主动脉瓣和二尖瓣舒张位置收缩位置）培养，瓣膜细胞保持存活。无细胞死亡被观察为由于缺少TUNEL阳性细胞 （图2H，I）或裂解的caspase-3表达的测定（未示出和Lieber等人，2010 11）。胶原分布（如可视化通过马森三色染色）类似于天然条件时在1％血清?...

Watch this Scientific Journal Video about Culturing Mouse Cardiac Valves in the Miniature Tissue Culture System at JoVE.com

Culturing Mouse Cardiac Valves in the Miniature Tissue Culture System

Here, we present an ex vivo flow model in which murine cardiac valves can be cultured allowing the study of the biology of the valve.

在小型组织培养体系培养老鼠心脏瓣膜

Heart valve disease is a major burden in the Western world and no effective treatment is available. This is mainly due to a lack of knowledge of the ...

culturing-mouse-cardiac-valves-in-the-miniature-tissue-culture-system

Research

JoVE Journal

Bioengineering

8.7K 次观看.  Leiden University Medical Center. Here, we present an ex vivo flow model in which murine cardiac valves can be cultured allowing the study of the biology of the valve.

视频: Culturing Mouse Cardiac Valves in the Miniature Tissue Culture System

A Method for Ovarian Follicle Encapsulation and Culture in a Proteolytically Degradable 3 Dimensional System

The ovarian follicle is the functional unit of the ovary that secretes sex hormones and supports oocyte maturation. In vitro follicle techniques provide a tool to model follicle development in order to investigate basic biology, and are further being developed as a technique to preserve fertility in the clinic1-4. Our in vitro culture system employs hydrogels in order to mimic the native ovarian environment by maintaining the 3D follicular architecture, cell-cell interactions and paracrine signaling that direct follicle development 5. Previously, follicles were successfully cultured in alginate, an inert algae-derived polysaccharide that undergoes gelation with calcium ions6-8. Alginate hydrogels formed at a concentration of 0.25% w/v were the most permissive for follicle culture, and retained the highest developmental competence 9. Alginate hydrogels are not degradable, thus an increase in the follicle diameter results in a compressive force on the follicle that can impact follicle growth10. We subsequently developed a culture system based on a fibrin-alginate interpenetrating network (FA-IPN), in which a mixture of fibrin and alginate are gelled simultaneously. This combination provides a dynamic mechanical environment because both components contribute to matrix rigidity initially; however, proteases secreted by the growing follicle degrade fibrin in the matrix leaving only alginate to provide support. With the IPN, the alginate content can be reduced below 0.25%, which is not possible with alginate alone 5. Thus, as the follicle expands, it will experience a reduced compressive force due to the reduced solids content. Herein, we describe an encapsulation method and an in vitro culture system for ovarian follicles within a FA-IPN. The dynamic mechanical environment mimics the natural ovarian environment in which small follicles reside in a rigid cortex and move to a more permissive medulla as they increase in size11. The degradable component may be particularly critical for clinical translation in order to support the greater than 106-fold increase in volume that human follicles normally undergo in vivo .

A new method for ovarian follicle encapsulation in a 3D fibrin-alginate interpenetrating network is described. This system combines structural support with proteolytic degradation to support the development of immature follicles to produce mature oocytes. This method may be applied to culture cell aggregates to maintain cell-cell contacts without limiting expansion.

卵泡在蛋白质降解的3维系统的封装和文化的一种方法

The ovarian follicle is the functional unit of the ovary that secretes sex hormones and supports oocyte maturation. In vitro  follicle techniques provide ...

科研

生物工程

Encapsulation of Cardiomyocytes in a Fibrin Hydrogel for Cardiac Tissue Engineering

Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying cellular responses under various culture conditions in vitro. The three dimensional environment more closely mimics what the cells observe in vivo due to the application of mechanical and chemical stimuli in all dimensions 1. Three-dimensional hydrogels can either be made from synthetic polymers such as PEG-DA 2 and PLGA 3 or a number of naturally occurring proteins such as collagen 4, hyaluronic acid 5 or fibrin 6,7. Hydrogels created from fibrin, a naturally occurring blood clotting protein, can polymerize to form a mesh that is part of the body's natural wound healing processes 8. Fibrin is cell-degradable and potentially autologous 9, making it an ideal temporary scaffold for tissue engineering.
Here we describe in detail the isolation of neonatal cardiomyocytes from three day old rat pups and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. Neonatal myocytes are a common cell source used for in vitro studies in cardiac tissue formation and engineering 4. Fibrin gel is created by mixing fibrinogen with the enzyme thrombin. Thrombin cleaves fibrinopeptides FpA and FpB from fibrinogen, revealing binding sites that interact with other monomers 10. These interactions cause the monomers to self-assemble into fibers that form the hydrogel mesh. Because the timing of this enzymatic reaction can be adjusted by altering the ratio of thrombin to fibrinogen, or the ratio of calcium to thrombin, one can injection mold constructs with a number of different geometries 11,12. Further we can generate alignment of the resulting tissue by how we constrain the gel during culture 13.
After culturing the engineered cardiac tissue constructs for two weeks under static conditions, the cardiac cells have begun to remodel the construct and can generate a contraction force under electrical pacing conditions 6. As part of this protocol, we also describe methods for analyzing the tissue engineered myocardium after the culture period including functional analysis of the active force generated by the cardiac muscle construct upon electrical stimulation, as well as methods for determining final cell viability (Live-Dead assay) and immunohistological staining to examine the expression and morphology of typical proteins important for contraction (Myosin Heavy Chain or MHC) and cellular coupling (Connexin 43 or Cx43) between myocytes.

We describe the isolation of neonatal cardiomyocytes and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. We describe methods for analyzing the tissue engineered myocardium after the culture period including active force generated upon electrical stimulation and cell viability and immunohistological staining.

心肌在心脏组织工程中的纤维蛋白凝胶的封装

Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying ...

Capillary Force Lithography for Cardiac Tissue Engineering

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart&#8217;s extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale2. Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering3-5.
A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling2. Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart6-9.
Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)8 and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function10-14.
Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively15,16. Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip and the PUA mold is placed on top. For UV-assisted CFL, the PU is then exposed to UV radiation (&#955; = 250-400 nm) for curing. For solvent-mediated CFL, the PLGA is embossed using heat (120 &#176;C) and pressure (100 kPa). After curing, the PUA mold is peeled off, leaving behind an ANFS for cell culture. Primary cells, such as neonatal rat ventricular myocytes, as well as human pluripotent stem cell-derived cardiomyocytes, can be maintained on the ANFS2.

In this protocol, we demonstrate the fabrication of biomimetic cardiac cell culture substrata made from two distinct polymeric materials using capillary force lithography. The described methods provide a scalable, cost-effective technique to engineer the structure and function of macroscopic cardiac tissues for in vitro and in vivo applications.

毛细力光刻技术在心脏组织工程

Cardiovascular disease remains the leading cause of death worldwide1. Cardiac tissue engineering holds much promise to deliver groundbreaking medical ...

Anatomical Reconstructions of the Human Cardiac Venous System using Contrast-computed Tomography of Perfusion-fixed Specimens

A detailed understanding of the complexity and relative variability within the human cardiac venous system is crucial for the development of cardiac devices that require access to these vessels. For example, cardiac venous anatomy is known to be one of the key limitations for the proper delivery of cardiac resynchronization therapy (CRT)1 Therefore, the development of a database of anatomical parameters for human cardiac venous systems can aid in the design of CRT delivery devices to overcome such a limitation. In this research project, the anatomical parameters were obtained from 3D reconstructions of the venous system using contrast-computed tomography (CT) imaging and modeling software (Materialise, Leuven, Belgium). The following parameters were assessed for each vein: arc length, tortuousity, branching angle, distance to the coronary sinus ostium, and vessel diameter.
	CRT is a potential treatment for patients with electromechanical dyssynchrony. Approximately 10-20% of heart failure patients may benefit from CRT2. Electromechanical dyssynchrony implies that parts of the myocardium activate and contract earlier or later than the normal conduction pathway of the heart. In CRT, dyssynchronous areas of the myocardium are treated with electrical stimulation. CRT pacing typically involves pacing leads that stimulate the right atrium (RA), right ventricle (RV), and left ventricle (LV) to produce more resynchronized rhythms. The LV lead is typically implanted within a cardiac vein, with the aim to overlay it within the site of latest myocardial activation. 
	We believe that the models obtained and the analyses thereof will promote the anatomical education for patients, students, clinicians, and medical device designers. The methodologies employed here can also be utilized to study other anatomical features of our human heart specimens, such as the coronary arteries. To further encourage the educational value of this research, we have shared the venous models on our free access website: <a href="http://www.vhlab.umn.edu/atlas" target="_blank">www.vhlab.umn.edu/atlas</a>.

The objective of this research is to recreate and then access the anatomy of the human cardiac venous system using 3D reconstructions generated from contrast-computed tomography scans.

人类心脏静脉系统使用对比计算机断层扫描灌注固定的标本解剖重建

A detailed  understanding of the complexity and relative variability within the human  cardiac venous system is crucial for the development of cardiac ...

Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage&#160;and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide insights on functional aspects of polymer valve design.

There has been renewed interest in developing polymer valves. Here, the objectives are to demonstrate the feasibility of modifying a commercial pulse duplicator to accommodate tri-leaflet geometries and to define a protocol to present polymer valve hydrodynamic data in comparison to native and prosthetic valve data collected under near-identical conditions.

协议相对液力评估的三单张聚合物阀

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of ...

Tissue Engineering of a Human 3D in vitro Tumor Test System

Cancer is one of the leading causes of death worldwide. Current therapeutic strategies are predominantly developed in 2D culture systems, which inadequately reflect physiological conditions in vivo. Biological 3D matrices provide cells an environment in which cells can self-organize, allowing the study of tissue organization and cell differentiation. Such scaffolds can be seeded with a mixture of different cell types to study direct 3D cell-cell-interactions. To mimic the 3D complexity of cancer tumors, our group has developed a 3D in vitro tumor test system.	
	Our 3D tissue test system models the in vivo situation of malignant peripheral nerve sheath tumors (MPNSTs), which we established with our decellularized porcine jejunal segment derived biological vascularized scaffold (BioVaSc). In our model, we reseeded a modified BioVaSc matrix with primary fibroblasts, microvascular endothelial cells (mvECs) and the S462 tumor cell line. For static culture, the vascular structure of the BioVaSc is removed and the remaining scaffold is cut open on one side (Small Intestinal Submucosa SIS-Muc). The resulting matrix is then fixed between two metal rings (cell crowns).	
	Another option is to culture the cell-seeded SIS-Muc in a flow bioreactor system that exposes the cells to shear stress. Here, the bioreactor is connected to a peristaltic pump in a self-constructed incubator. A computer regulates the arterial oxygen and nutrient supply via parameters such as blood pressure, temperature, and flow rate. This setup allows for a dynamic culture with either pressure-regulated pulsatile or constant flow.	
	In this study, we could successfully establish both a static and dynamic 3D culture system for MPNSTs. The ability to model cancer tumors in a more natural 3D environment will enable the discovery, testing, and validation of future pharmaceuticals in a human-like model.

Tissue Engineering of a Human 3D in vitro Tumor Test System

Methods to create human 3D tumor tissues as test systems are described. These technologies are based on a decellularized Biological Vascularized Scaffold (BioVaSc), primary human cells and a tumor cell line, which can be cultured under static as well as under dynamic conditions in a flow bioreactor.

一个人的3D组织工程<em&gt;在体外</em&gt;肿瘤测试系统

Cancer is one of the leading causes of death worldwide.  Current therapeutic strategies are predominantly developed in 2D culture  systems, which ...

An In Vitro Organ Culture Model of the Murine Intervertebral Disc

Intervertebral disc (IVD) degeneration is a significant contributor to low back pain. The IVD is a fibrocartilaginous joint that serves to transmit and dampen loads in the spine. The IVD consists of a proteoglycan-rich nucleus pulposus (NP) and a collagen-rich annulus fibrosis (AF) sandwiched by cartilaginous end-plates. Together with the adjacent vertebrae, the vertebrae-IVD structure forms a functional spine unit (FSU). These microstructures contain unique cell types as well as unique extracellular matrices. Whole organ culture of the FSU preserves the native extracellular matrix, cell differentiation phenotypes, and cellular-matrix interactions. Thus, organ culture techniques are particularly useful for investigating the complex biological mechanisms of the IVD. Here, we describe a high-throughput approach for culturing whole lumbar mouse FSUs that provides an ideal platform for studying disease mechanisms and therapies for the IVD. Furthermore, we describe several applications that utilize this organ culture method to conduct further studies including contrast-enhanced microCT imaging and three-dimensional high-resolution finite element modeling of the IVD.

An In Vitro Organ Culture Model of the Murine Intervertebral Disc

Whole organ culture of the intervertebral disc (IVD) preserves the native extracellular matrix, cell phenotypes, and cellular-matrix interactions. Here we describe an IVD culture system using mouse lumbar and caudal IVDs in their functional spinal units and several applications utilizing this system.

一个<em&gt;体外</em鼠类的椎间盘&gt;器官培养模型

Intervertebral disc (IVD) degeneration is a significant contributor to low back pain. The IVD is a fibrocartilaginous joint that serves to transmit and ...

Culturing Mammalian Cells in Three-dimensional Peptide Scaffolds

A useful technique for culturing cells in a self-assembling nanofiber three-dimensional (3D) scaffold is described. This culture system recreates an environment that closely mimics the structural features of non-polarized tissue. Furthermore, the particular intrinsic nanofiber structure of the scaffold makes it transparent to visual light, which allows for easy visualization of the sample under microscopy. This advantage was largely used to study cell migration, organization, proliferation, and differentiation and thus any development of their particular cellular function by staining with specific dyes or probes. Furthermore, in this work, we describe the good performance of this system to easily study the redifferentiation of expanded human articular chondrocytes into cartilaginous tissue. Cells were encapsulated into self-assembling peptide scaffolds and cultured under specific conditions to promote chondrogenesis. Three-dimensional cultures showed good viability during the 4 weeks of the experiment. As expected, samples cultured with chondrogenic inducers (compared to non-induced controls) stained strongly positive for toluidine blue (which stains glycosaminoglycans (GAGs) that are highly present in cartilage extracellular matrix) and expressed specific molecular markers, including collagen type I, II and X, according to Western Blot analysis. This protocol is easy to perform and can be used at research laboratories, industries and for educational purposes in laboratory courses.

Here, we present a protocol to obtain 3D-culture systems in self-assembling peptide scaffolds to promote the differentiation of dedifferentiated human articular chondrocytes into cartilage-like tissue.

三维肽支架中哺乳动物细胞的培养

A useful technique for culturing cells in a self-assembling nanofiber three-dimensional (3D) scaffold is described. This culture system recreates an ...

A Net Mold-based Method of Scaffold-free Three-Dimensional Cardiac Tissue Creation

This protocol describes a novel and easy net mold-based method to create three-dimensional (3-D) cardiac tissues without additional scaffold material. Human-induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs), human cardiac fibroblasts (HCFs), and human umbilical vein endothelial cells (HUVECs) are isolated and used to generate a cell suspension with 70% iPSC-CMs, 15% HCFs, and 15% HUVECs. They are co-cultured in an ultra-low attachment "hanging drop" system, which contains micropores for condensing hundreds of spheroids at one time. The cells aggregate and spontaneously form beating spheroids after 3 days of co-culture. The spheroids are harvested, seeded into a novel mold cavity, and cultured on a shaker in the incubator. The spheroids become a mature functional tissue approximately 7 days after seeding. The resultant multilayered tissues consist of fused spheroids with satisfactory structural integrity and synchronous beating behavior. This new method has promising potential as a reproducible and cost-effective method to create engineered tissues for the treatment of heart failure in the future.

This protocol describes a net mold-based method to create three-dimensional scaffold-free cardiac tissues with satisfactory structural integrity and synchronous beating behavior.

基于网模的无支架三维心脏组织创建方法

This protocol describes a novel and easy net mold-based method to create three-dimensional (3-D) cardiac tissues without additional scaffold material. ...

Biaxial Mechanical Characterizations of Atrioventricular Heart Valves

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive models, which provide a mathematical representation of the mechanical function of those structures. This presented biaxial mechanical testing protocol involves (i) tissue acquisition, (ii) the preparation of tissue specimens, (iii) biaxial mechanical testing, and (iv) postprocessing of the acquired data. First, tissue acquisition requires obtaining porcine or ovine hearts from a local Food and Drug Administration-approved abattoir for later dissection to retrieve the valve leaflets. Second, tissue preparation requires using tissue specimen cutters on the leaflet tissue to extract a clear zone for testing. Third, biaxial mechanical testing of the leaflet specimen requires the use of a commercial biaxial mechanical tester, which consists of force-controlled, displacement-controlled, and stress-relaxation testing protocols to characterize the leaflet tissue&#39;s mechanical properties. Finally, post-processing requires the use of data image correlation techniques and force and displacement readings to summarize the tissue&#39;s mechanical behaviors in response to external loading. In general, results from biaxial testing demonstrate that the leaflet tissues yield a nonlinear, anisotropic mechanical response. The presented biaxial testing procedure is advantageous to other methods since the method presented here allows for a more comprehensive characterization of the valve leaflet tissue under one unified testing scheme, as opposed to separate testing protocols on different tissue specimens. The proposed testing method has its limitations in that shear stress is potentially present in the tissue sample. However, any potential shear is presumed negligible.

This protocol involves characterizations of atrioventricular valve leaflets with force-controlled, displacement-controlled, and stress-relaxation biaxial mechanical testing procedures. Results acquired with this protocol can be used for constitutive model development to simulate the mechanical behavior of functioning valves under a finite element simulation framework.

房室心脏瓣膜的双轴力学特性

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive ...