Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
Allergy. 2014 Aug;69(8):1102-11. doi: 10.1111/all.12430. Epub 2014 Jun 4.
Inflammation in the small airways might contribute to incomplete asthma disease control despite intensive treatment in some subgroups of patients. Exhaled NO (FeNO) is a marker of inflammation in asthma and the estimated NO contribution from small airways (CalvNO ) is believed to reflect distal inflammation. Recent studies recommend adjustments of CalvNO for trumpet model and axial diffusion (TMAD-adj). This study aimed to investigate the clinical correlates of CalvNO , both TMAD-adjusted and unadjusted.
Asthma symptoms, asthma control, lung function, bronchial responsiveness, blood eosinophils, atopy and treatment level were assessed in 410 subjects, aged 10-35 years. Exhaled NO was measured at different flow-rates and CalvNO calculated, with TMAD-adjustment according to Condorelli.
Trumpet model and axial diffusion-adjusted CalvNO was not related to daytime wheeze (P = 0.27), FEF50 (P = 0.23) or bronchial responsiveness (P = 0.52). On the other hand, unadjusted CalvNO was increased in subjects with daytime wheeze (P < 0.001), decreased FEF50 (P = 0.02) and with moderate-to-severe compared to normal bronchial responsiveness (P < 0.001). All these characteristics correlated with increased FeNO (all P < 0.05). Unadjusted CalvNO was positively related to bronchial NO flux (J'awNO ) (r = 0.22, P < 0.001) while TMAD-adjCalvNO was negatively related to J'awNO (r = -0.38, P < 0.001).
Adjusted CalvNO was not associated with any asthma characteristics studied in this large asthma cohort. However, both FeNO and unadjusted CalvNO related to asthma symptoms, lung function and bronchial responsiveness. We suggest a potential overadjustment by current TMAD-corrections, validated in healthy or unobstructed asthmatics. Further studies assessing axial diffusion in asthmatics with different degrees of airway obstruction and the validity of proposed TMAD-corrections are warranted.
在一些患者亚组中，尽管进行了强化治疗，但小气道炎症仍可能导致哮喘疾病控制不完整。呼出气一氧化氮（FeNO）是哮喘炎症的标志物，估计来自小气道的 NO 贡献（CalvNO）被认为反映了远端炎症。最近的研究建议调整 CalvNO 以适应喇叭模型和轴向扩散（TMAD-调整）。本研究旨在探讨 CalvNO 的临床相关性，包括 TMAD 调整和未调整的 CalvNO。
对 410 名年龄在 10-35 岁的哮喘患者进行哮喘症状、哮喘控制、肺功能、支气管反应性、血嗜酸性粒细胞、过敏和治疗水平评估。在不同流量下测量呼出气一氧化氮，并根据 Condorelli 计算 CalvNO，同时进行 TMAD 调整。
喇叭模型和轴向扩散调整后的 CalvNO 与日间喘息（P=0.27）、FEF50（P=0.23）或支气管反应性（P=0.52）无关。另一方面，在日间有喘息的患者中，未经调整的 CalvNO 增加（P<0.001），FEF50 降低（P=0.02），中度至重度支气管反应性与正常支气管反应性相比（P<0.001）。所有这些特征均与 FeNO 增加相关（均 P<0.05）。未经调整的 CalvNO 与支气管 NO 通量（J'awNO）呈正相关（r=0.22，P<0.001），而 TMAD 调整后的 CalvNO 与 J'awNO 呈负相关（r=-0.38，P<0.001）。
在这个大型哮喘队列中，调整后的 CalvNO 与研究的任何哮喘特征均无关。然而，FeNO 和未经调整的 CalvNO 均与哮喘症状、肺功能和支气管反应性相关。我们建议对目前的 TMAD 校正进行潜在的过度校正，这些校正已在健康或未阻塞的哮喘患者中得到验证。需要进一步研究评估不同气道阻塞程度的哮喘患者的轴向扩散以及提出的 TMAD 校正的有效性。
