Airway trees in the Anthropocene.
Airway trees in the Anthropocene.
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人类世的气道树。
DOI：
10.1152/japplphysiol.00666.2022
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Smith,BenjaminM
中科院分区：
文献类型：
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作者：
Smith,BenjaminM
人体气道树是气体交换的重要管道，也是我们抵御有害气溶胶的第一道防线。气道树状结构是气流阻力的决定因素，而气流阻力又是最大自主通气的重要决定因素。如果将最大运动能力视为一种进化选择压力，那么值得注意的是，没有疾病的人类并没有受到通风限制。由此可见，缺乏最大化通风的进化选择压力可能导致了人类气道树结构的变异。尽管这种理论很难（如果不是不可能的话）被证明，但它有可能描述现代人类气道树结构和功能的分布。至少从19世纪解剖学家Christoph Theodor Aeby(1)和医生William Ewart(2)描述死后标本中气道树枝模式的变化以来，人类气道树结构的变化就已经被认识到。不幸的是，这种采样策略容易受到选择偏差的影响，并且在试图理解体内结构-功能关系时具有重要的局限性。最近，成像技术帮助克服了这些限制。例如，Green等人(3)在本刊中首次提出的“功能失调”的概念，已经在普通人群中得到证实，使用计算机断层扫描（CT）直接评估相对于肺体积的气道树口径（气道-肺比；ALR; 4）。ALR的个体间变异始于成年早期(5)，延伸至终末细支气管(6)，并与晚年发生的阻塞性肺疾病密切相关(4)，这是1974年首次提出的假设(3)。除了气道树“结构失调”之外，越来越多的结构特性已经通过影像学和肺功能测量进行了评估。这些指标包括总气道计数（TAC; 7）、气道树分形维数（AFD; 8）、气道管腔表面积体积比（SA/V; 9）等。到目前为止，缺乏的是对气道树的这些不同结构特性的相互关系的理解，它们在无临床肺部疾病的无症状个体中的分布，以及它们与肺功能测量的独立关联。
The human airway tree serves as a vital conduit for gasexchange and our first line of defense against noxious aerosols. Airway tree structure is a determinant of airflow resistance, which in turn, is an important determinant of maximum voluntary ventilation. If one considers maximum exercise capacity as an evolutionary selection pressure, it is notable that humans, absent of disease, are not ventilation limited. It follows that a lack of evolutionary selection pressure to maximize ventilation may have permitted variation in airway tree structure to manifest among humans. Although such a theory is difficult if not impossible to prove, it is possible to describe the distribution of airway tree structure and function among modern humans.Variation in human airway tree structure has been appreciated since at least the 19th century when anatomist Christoph Theodor Aeby (1) and physician William Ewart (2) described variations in airway tree branch patterns in postmortem specimens. Unfortunately, this sampling strategy is susceptible to selection bias and has important limitations when trying to understand in vivo structure-function relationships. More recently, imaging techniques have helped to overcome these limitations. For example, the concept of “dysanapsis,” first introduced in this journal by Green et al.(3), has since been confirmed in the general population using computed tomography (CT) to assess directly airway tree caliber relative to lung volume (airway-to-lung ratio; ALR; 4). Interindividual variation in ALR is established by early adulthood (5), extending to the terminal bronchioles (6), and is strongly associated with incident obstructive lung disease later in life (4), as was first hypothesized back in 1974 (3). Beyond airway tree “dysanapsis,” a growing list of structural properties have been assessed by imaging and related to measures of lung function. These include total airway count (TAC; 7), airway tree fractal dimension (AFD; 8), airway lumen surface area-to-volume ratio (SA/V; 9), and many others. What has been lacking, until now, is an understanding of the interrelationship of these various structural properties of the airway tree, their distribution among asymptomatic individuals free of clinical lung disease, and their independent associations with measures of lung function.