Reimelt Alex M, Vasilescu Dragoș M, Beare Richard, Labode Jonas, Knudsen Lars, Grothausmann Roman
Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.
Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
Am J Physiol Lung Cell Mol Physiol. 2023 Mar 1;324(3):L358-L372. doi: 10.1152/ajplung.00069.2022. Epub 2023 Jan 31.
Mechanical forces affect the alveolar shape, depending on location and tissue composition, and vary during the respiratory cycle. This study performs alveolar morphomics in different lobes of human lungs using models generated from three-dimensional (3-D) micro-computed tomography (microCT) images. Cylindrical tissue samples (1.6 cm × 2 cm) were extracted from two nontransplantable donor lungs (one ex-smoker and one smoker, 3 samples per subject) that were air-inflated and frozen solid in liquid nitrogen vapor. Samples were scanned with microCT (11 µm/voxel). Within representative cubic regions of interest (5.5 mm edge length), alveoli were segmented to produce corresponding 3-D models from which quantitative data were obtained. The surface of segmented alveoli (n_alv_total = 23,587) was divided into individual planar surfaces (facets) and angles between facet normals were calculated. Moreover, the number of neighboring alveoli was estimated for every alveolus. In this study, we examined intraindividual differences in alveolar morphology, which were reproducible in the lungs of two subjects. The main aspects are higher mean alveolar volumes (v_alv: 6.64 × 10 and 6.63 × 10 µm vs. 5.78 × 10 and 6.29 × 10 µm) and surface sizes (s_alv: 0.19 and 0.18 mm vs. 0.17 mm in both lower lobes) in both upper lung lobes compared with the lower lobes. An increasing number of facets (f_alv) from top to bottom (12 and 14 in the upper lobes; 14 and 15 in the lower lobes), as well as a decreasing number of alveolar neighbors (nei_alv: 9 and 8 in the upper lobes; 8 and 7 in the lower lobes) from the upper lobes to the lower lobes were observed. We could observe an increasing ratio of alveolar entrance size to the surface size of the alveoli from top to bottom (S_ratio_alv: 0.71 and 0.64 in the upper lobes, 0.73 and 0.70 in the lower lobes). The angles between facet normals (ang_alv) were larger in the upper lobes (67.72° and 62.44°) of both lungs than in the lower lobes (66.19° and 61.30°). By using this new approach of analyzing alveolar 3-D data, which enables the estimation of facet, neighbor, and shape characteristics, we aimed to establish the baseline measures for in-depth studies of mechanical conditions and morphology.
机械力会影响肺泡的形状，这取决于其位置和组织构成，并且在呼吸周期中会发生变化。本研究利用从三维（3-D）微计算机断层扫描（microCT）图像生成的模型，对人类肺部不同叶进行肺泡形态学分析。从两个不可用于移植的供体肺（一名曾经吸烟者和一名吸烟者，每位受试者3个样本）中提取圆柱形组织样本（1.6厘米×2厘米），这些肺在充气状态下于液氮蒸汽中速冻。样本用microCT（11微米/体素）进行扫描。在代表性的立方感兴趣区域（边长5.5毫米）内，对肺泡进行分割以生成相应的3-D模型，从中获取定量数据。将分割后的肺泡表面（n_alv_total = 23,587）划分为单个平面表面（小平面），并计算小平面法线之间的角度。此外，估计每个肺泡的相邻肺泡数量。在本研究中，我们检查了两名受试者肺部中可重复的肺泡形态个体内差异。主要方面是，与下叶相比，上叶的平均肺泡体积更高（v_alv：6.64×10和6.63×10微米，而下叶为5.78×10和6.29×10微米）以及表面尺寸更大（s_alv：上叶为0.19和0.18毫米，而下叶均为0.17毫米）。从上到下，小平面数量增加（上叶为12和14个；下叶为14和15个），并且从肺上叶到下叶，肺泡邻居数量减少（nei_alv：上叶为9和8个；下叶为8和7个）。我们可以观察到，从上到下，肺泡入口尺寸与肺泡表面尺寸的比值增加（S_ratio_alv：上叶为0.71和0.64，下叶为0.73和0.70）。两肺上叶的小平面法线之间的角度（ang_alv）（67.72°和62.44°）大于下叶（66.19°和61.30°）。通过使用这种分析肺泡3-D数据的新方法，该方法能够估计小平面、邻居和形状特征，我们旨在为深入研究机械条件和形态建立基线测量值。
