Del Donno M, Chetta A, Foresi A, Gavaruzzi G, Ugolotti G, Olivieri D
Istituto di Clinica delle Malattie dell'Apparato Respiratorio, Università di Parma, Italy.
Chest. 1997 May;111(5):1255-60. doi: 10.1378/chest.111.5.1255.
Lung epithelial permeability of asthmatic patients has been reported to be similar or lower than that of healthy subjects and to be correlated or not to bronchial hyperresponsiveness. To clarify these discrepancies, we evaluated 99mTc-DTPA pulmonary clearance in a group of carefully selected asthmatic patients with mild, stable asthma (n = 13; seven women; mean age +/- SD = 27.69 +/- 6.63 years), and compared them with a group of healthy, nonsmoking subjects (n = 8; six women; mean age +/- SD = 24.38 +/- 5.15 years). Selection criteria for asthmatics were as follows: baseline FEV1 > or = 80% of predicted values, no bronchial infections, and/or no asthma attacks during 4 weeks prior to study and peak expiratory flow rate variability lower than 20%, over a period of 3 weeks. Patients controlled symptoms with beta 2-adrenergic drugs only, regularly or on demand. Mean baseline FEV1 (+/-SD) as percent of predicted was 102.38 +/- 13.97 and 112.88 +/- 18.36, respectively (p < 0.05). In the asthmatic group, bronchial responsiveness to methacholine (PC20 M FEV1) ranged between 0.55 and 28.5 mg/mL. Mean value (+/-SD) of DTPA clearance from lungs to blood (evaluated on the first 10 min out of 30 min of the curves) in the asthmatic group was not different from that of control group (68.31 +/- 21.46 and 69.5 +/- 15.73). In the asthmatic patients, there was no correlation between PC20 M values and DTPA T1/2 min of the whole lung, nor between PC20 M and inner and outer lung clearance zones. Moreover, both in asthmatics and healthy subjects, DTPA clearance of outer (alveolar) zones was significantly faster than that of inner (bronchial) zones (57.69 +/- 19.94 vs 102.08 +/- 38.19, p < 0.001, and 59.75 +/- 12.49 vs 103.5 +/- 31.86, p < 0.003, respectively). Our data show that DTPA clearance in patients with stable asthma is similar to that found in healthy subjects; it is not correlated to degree of bronchial responsiveness and occurs more rapidly in the outer zones than in the inner zones, both in asthmatic patients and in healthy subjects. Thus, to date, DTPA clearance index is not a valid tool for identifying and/or monitoring asthmatic patients.
据报道，哮喘患者的肺上皮通透性与健康受试者相似或更低，且与支气管高反应性相关或不相关。为了澄清这些差异，我们评估了一组精心挑选的轻度、稳定哮喘患者（n = 13；7名女性；平均年龄±标准差 = 27.69 ± 6.63岁）的99mTc - DTPA肺清除率，并将其与一组健康、不吸烟的受试者（n = 8；6名女性；平均年龄±标准差 = 24.38 ± 5.15岁）进行比较。哮喘患者的入选标准如下：基线FEV1≥预测值的80%，无支气管感染，和/或在研究前4周内无哮喘发作，且在3周内呼气峰值流速变异性低于20%。患者仅使用β2 - 肾上腺素能药物控制症状，规律使用或按需使用。预测值百分比的平均基线FEV1（±标准差）分别为102.38 ± 13.97和112.88 ± 18.36（p < 0.05）。在哮喘组中，对乙酰甲胆碱的支气管反应性（PC20 M FEV1）范围为0.55至28.5 mg/mL。哮喘组中从肺到血液的DTPA清除率（在曲线的30分钟中的前10分钟评估）的平均值（±标准差）与对照组无差异（68.31 ± 21.46和69.5 ± 15.73）。在哮喘患者中，PC20 M值与全肺的DTPA T1/2分钟之间、PC20 M与肺内和肺外清除区之间均无相关性。此外，在哮喘患者和健康受试者中，肺外（肺泡）区的DTPA清除率均明显快于肺内（支气管）区（分别为57.69 ± 19.94对102.08 ± 38.19，p < 0.001，以及59.75 ± 12.49对103.5 ± 31.86，p < 0.003）。我们的数据表明，稳定哮喘患者的DTPA清除率与健康受试者相似；它与支气管反应性程度无关，并且在哮喘患者和健康受试者中，肺外区的清除率均比肺内区更快。因此，迄今为止，DTPA清除指数不是识别和/或监测哮喘患者的有效工具。
