Are airway vessels really important in asthma? This question has become more relevant since the finding of increased vessel numbers and vascularity in the submucosa of patients with relatively mild asthma.1 It has been confirmed again by Salvato in this issue of Thorax.2 The description of asthmatic bronchial vessels has been extended beyond traditional views of vessel function. As well as supplying nutrients to the vessel wall, temperature regulation, and facilitating humidification of the airway environment, vessels have several other important functions in the asthmatic response that may contribute to airflow obstruction. The study by Salvato2 comments on each of these components.

Firstly, angiogenesis has been described in airway sections, identifying more vessels in asthma when anti-collagen IV antibodies were used to detect vascular basement membrane.1 ,3 ,4Interestingly, collagen IV has been shown to be essential for the development of new endothelial cell tubes.5 Studies …