Trabeculae carneae as models of the ventricular walls: implications for the delivery of oxygen.
Trabeculae carneae as models of the ventricular walls: implications for the delivery of oxygen.
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DOI：
10.1085/jgp.200910276
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发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Loiselle D
中科院分区：
文献类型：
--
作者：
Goo S;Joshi P;Sands G;Gerneke D;Taberner A;Dollie Q;LeGrice I;Loiselle D
肌小梁是心脏中最小的线性排列的肌细胞的自然产生的集合。是研究离体完整心肌功能的首选制剂。在体内，骨小梁是唯一的从两个独立的来源接收氧气：冠状动脉循环和周围的心室血液。由于冠状动脉中的氧分压（PO2）在两个心室的标本中是相同的，而心室血液的氧分压在左心室比右心室高2.5倍，因此小梁代表了一个“天然实验室”，在其中检查“血管外”PO2对心肌组织毛细血管化程度的影响。我们利用这一优势来测试四个假设。(1)在来自任一心室的小梁中，细胞的外周环缺乏毛细血管。(2)因此，来自任一心室的足够小的小梁完全没有毛细血管。(3)两个心室标本的毛细血管与肌细胞比率与其各自心室壁的比率相同。(4)两个心室的样本中毛细血管与肌细胞的比例相当，反映了体内相同的能量需求，由相同的收缩频率和相当的壁应力驱动。我们将共聚焦荧光成像应用于横截面中的小梁，随后使用半自动分割技术来区分毛细血管和肌细胞。我们量化了两个心室的小梁的毛细血管与肌细胞的比率，并将其与心室游离壁和间隔的比率进行了比较。通过数学建模进一步进行定量解释，使用椭圆形横截面的扩散方程的经典解，以及适用于包含毛细血管和非呼吸胶原蛋白索的任意形状的横截面的新方法。
Trabeculae carneae are the smallest naturally arising collections of linearly arranged myocytes in the heart. They are the preparation of choice for studies of function of intact myocardium in vitro. In vivo, trabeculae are unique in receiving oxygen from two independent sources: the coronary circulation and the surrounding ventricular blood. Because oxygen partial pressure (PO2) in the coronary arterioles is identical in specimens from both ventricles, whereas that of ventricular blood is 2.5-fold higher in the left ventricle than in the right ventricle, trabeculae represent a “natural laboratory” in which to examine the influence of “extravascular” PO2 on the extent of capillarization of myocardial tissue. We exploit this advantage to test four hypotheses. (1) In trabeculae from either ventricle, a peripheral annulus of cells is devoid of capillaries. (2) Hence, sufficiently small trabeculae from either ventricle are totally devoid of capillaries. (3) The capillary-to-myocyte ratios in specimens from either ventricle are identical to those of their respective walls. (4) Capillary-to-myocyte ratios are comparable in specimens from either ventricle, reflecting equivalent energy demands in vivo, driven by identical contractile frequencies and comparable wall stresses. We applied confocal fluorescent imaging to trabeculae in cross section, subsequently using semi-automated segmentation techniques to distinguish capillaries from myocytes. We quantified the capillary-to-myocyte ratios of trabeculae from both ventricles and compared them to those determined for the ventricular free walls and septum. Quantitative interpretation was furthered by mathematical modeling, using both the classical solution to the diffusion equation for elliptical cross sections, and a novel approach applicable to cross sections of arbitrary shape containing arbitrary disposition of capillaries and non-respiring collagen cords.
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影响因子：
2.5
作者：
Sands, GB;Gerneke, DA;Legrice, IJ
通讯作者：
Legrice, IJ
影响因子：
39.2
作者：
Goodman, SN
通讯作者：
Goodman, SN
影响因子：
4.1
作者：
Androjna, Caroline;Gatica, Jorge E.;Derwin, Kathleen A.
通讯作者：
Derwin, Kathleen A.
影响因子：
2
作者：
MURRAY, JD
通讯作者：
MURRAY, JD
DOI：
10.1152/ajpcell.2002.282.1.c213
发表时间：
2002-01-01
影响因子：
5.5
作者：
Clendenon, JL;Phillips, CL;Dunn, KW
通讯作者：
Dunn, KW