Abstract
Clinical markers of subtle cardiovascular autonomic dysfunction predict incident COPD: the potential role of neurohumoral activation http://ow.ly/mUcW30jMnPC
To the Editor:
I read with great interest the recent work by Ricci et al. [1] published in the European Respiratory Journal. This insightful population-based study followed a very large cohort without baseline airflow obstruction for 32 years. Interestingly, baseline orthostatic blood pressure decrease, as well as increased resting heart rate, was associated with reduced lung function during follow-up. The authors consequently suggested that subtle signs of cardiovascular autonomic dysfunction may precede the development of chronic obstructive pulmonary disease (COPD).
I would like to take this notion further and suggest that the observed association might be explained by subtle neurohumoral activation. With a variety of methods, we and others have described striking neurohumoral activation in patients with moderate to severe COPD [2–5]. Several mechanisms, such as hypoxia, chemoreflexes, impaired baroreflexes, less physical activity and increased work of breathing, are likely to contribute to sympathetic activation in COPD.
Since microneurography as a gold standard for the evaluation of sympathetic activity is a challenging method and has never been performed in a population-based cohort, it is not possible to prove this assumption. However, in other diseases, such as heart failure and obstructive sleep apnoea, the concept of neurohumoral activation and autonomic nervous system imbalance with increased sympathetic activation and reduced parasympathetic activity has long been recognised, and is related to increased resting heart rate, as well as increased morbidity and mortality [6, 7].
Thus, it is reasonable to suggest that orthostatic blood pressure decrease and increased resting heart rate, as observed by Ricci et al. [1], are a sign of subtle neurohumoral activation. This neurohumoral activation might indeed contribute to progression of lung disease by pro-inflammatory activity, as Ricci et al. [1] suggested in their discussion.
Whatever the underlying mechanism, the novel findings by Ricci et al. [1] shed light on the importance of the autonomic nervous system in the pathogenesis of chronic diseases such as COPD.
Footnotes
Conflict of interest: None declared.
- Received April 18, 2018.
- Accepted April 19, 2018.
- Copyright ©ERS 2018