Braga F J, Manço J C, Souza J F, Ferrioli E, De Andrade J, Iazigi N
Centre of Image Sciences and Medical Physics, Ribeirão Preto School of Medicine, University of São Paulo, Brazil.
Nucl Med Commun. 1996 Nov;17(11):971-4. doi: 10.1097/00006231-199611000-00008.
Age is known to reduce the efficacy of body organs and systems, even in the absence of disease. The alveolar-capillary clearance (ACC) rate is representative of the alveolar-capillary barrier's functional state. We studied 29 healthy non-smokers, who were selected after clinical and radiographic evaluation. The patients were divided into three groups based on age: Group I, < or = 30 years (n = 10); Group II, 31-55 years (n = 9); Group III, > or = 56 years (n = 10). Each patient inhaled 750 MBq 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) aerosol generated by a Venticis nebulizer (particles with a mean diameter of 1.1 microns) for 5 min. Forty frames of 30 s duration each were acquired and the ACC rates for the right and left lungs determined using a computer program. The mean ACC rates for the three groups were as follows: Group I, 1.31% min-1; Group II, 1.08% min-1; Group III, 0.76% min-1. The differences between Groups I and III (P < 0.001) and Groups II and III (P = 0.03) were shown to be significant. There was no significant difference between Groups I and II. Possible explanations for an age-related reduction in ACC rates include a reduction in the internal alveolar surface, the closure of the small airways, a reduction in the lung blood capillaries and a reduction in cardiac output. We conclude that there appears to be an age-related reduction in ACC rates in healthy non-smokers, even in the absence of clinically and radiographically detectable lung disease. However, larger studies are required.
众所周知，即使在没有疾病的情况下，年龄也会降低身体器官和系统的效能。肺泡-毛细血管清除率（ACC）是肺泡-毛细血管屏障功能状态的代表。我们研究了29名健康的非吸烟者，这些人经过临床和影像学评估后入选。根据年龄将患者分为三组：第一组，≤30岁（n = 10）；第二组，31 - 55岁（n = 9）；第三组，≥56岁（n = 10）。每位患者使用Venticis雾化器（平均直径为1.1微米的颗粒）吸入750 MBq的99锝-二乙三胺五乙酸（99Tcm-DTPA）气雾剂5分钟。采集40帧，每帧持续30秒，并使用计算机程序确定左右肺的ACC率。三组的平均ACC率如下：第一组，1.31%每分钟；第二组，1.08%每分钟；第三组，0.76%每分钟。第一组和第三组（P < 0.001）以及第二组和第三组（P = 0.03）之间的差异具有统计学意义。第一组和第二组之间没有显著差异。与年龄相关的ACC率降低的可能解释包括肺泡内表面积减少、小气道闭合、肺血毛细血管减少和心输出量减少。我们得出结论，即使在没有临床和影像学可检测到的肺部疾病的情况下，健康非吸烟者的ACC率似乎也存在与年龄相关的降低。然而，需要进行更大规模的研究。
