Is Length an Appropriate Estimator to Characterize Pulmonary Alveolar Capillaries? A Critical Evaluation in the Human Lung
Is Length an Appropriate Estimator to Characterize Pulmonary Alveolar Capillaries? A Critical Evaluation in the Human Lung
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DOI：
10.1002/ar.21158
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发表时间：
2010-07-01
影响因子：
2
通讯作者：
Ochs, Matthias
中科院分区：
文献类型：
--
作者：
Muehlfeld, Christian;Weibel, Ewald R.;Ochs, Matthias
总毛细血管长度的体视学估计已被用来表征发育过程或病理生理条件下肺泡毛细血管网络（ACN）的变化。在这里，我们分析了长度估计是否适合描述 ACN 的 3D 性质。 Gehr 等人之前研究过五个人肺的半薄切片。 (Respir Physiol 1978; 32:121-140)，用于使用“基于设计”或“基于模型”的体视学方法来估计肺泡毛细血管长度。基于设计的方法涉及对与参考空间的定义区域相关的毛细管轮廓进行计数。基于模型的方法基于毛细管是圆管的假设，并且长度是根据毛细管体积和表面积计算的。基于模型的方法得出的毛细管总长度平均值为 6,950 公里（SD：3,108 公里），基于设计的方法得出的平均值为 2,746 公里（SD：722 公里）。由于 ACN 的几何形状，这两种方法都带有不可预测的偏差。基于设计的方法产生的偏差与 ACN 中毛细管段的半径和长度之间的比率、分支点的数量和毛细管的缠绕成正比。由于毛细管的真实非圆柱形形状和网络结构，基于模型的方法存在偏差。总之，不建议估计 ACN 中毛细血管的总长度，因为 ACN 的几何形状不满足体视长度估计的要求。在开发新方法之前，应优先考虑毛细管体积和表面积的无偏估计。 Anat Rec，293:1270-1275，2010。(C)2010 Wiley-Liss, Inc.
Stereological estimations of total capillary length have been used to characterize changes in the alveolar capillary network (ACN) during developmental processes or pathophysiological conditions. Here, we analyzed whether length estimations are appropriate to describe the 3D nature of the ACN. Semi-thin sections of five human lungs, previously investigated by Gehr et al. (Respir Physiol 1978; 32:121-140), were used to estimate alveolar capillary length using a "design-based" or a "model-based" stereological approach. The design-based approach involves counting of capillary profiles related to a defined area of the reference space. The model-based approach bases on the assumption that capillaries are round tubes and length was calculated from capillary volume and surface area. The model-based approach provided a mean of 6,950 km (SD: 3,108 km) for total capillary length, the design-based approach resulted in a mean of 2,746 km (SD: 722 km). Because of the geometry of the ACN both approaches carry an unpredictable bias. The bias incurred by the design-based approach is proportional to the ratio between radius and length of the capillary segments in the ACN, the number of branching points and the winding of the capillaries. The model-based approach is biased because of the real noncylindrical shape of capillaries and the network structure. In conclusion, the estimation of the total length of capillaries in the ACN cannot be recommended as the geometry of the ACN does not fulfill the requirements for stereological length estimation. Until new methods are being developed, the unbiased estimates of capillary volume, and surface area should be preferred. Anat Rec, 293:1270-1275, 2010. (C) 2010 Wiley-Liss, Inc.