It has been recognised for several hundred years that the bronchial vasculature is an extensive one with early descriptions by Ruysch and possibly Da Vinci.¹ However, its function and regulation in health and in disease remain poorly understood. Studies a number of years ago suggested an increased number of bronchial vessels in asthma where increased collagen IV staining, a marker of new vessels, was seen in bronchial biopsies of asthmatic airways compared with controls.² Subsequent studies by the same group and by Salvato and colleagues have confirmed the presence of angiogenesis in the bronchial circulation in asthma.^3,4 There are a number of candidate angiogenic factors for these changes, perhaps the most important of which are vascular endothelial growth factor (VEGF) and the angiopoietins which are distinct molecules that act together at different stages of angiogenic processes in several biological systems.^{5,6,7,8,9,10,11} Other molecules with angiogenic potential are fibroblast growth factor,⁹ angiogenin,⁹ and chemokines such as interleukin (IL)-8¹² and eotaxin.¹³ Interestingly, angiogenesis seems to be a feature of inflammatory diseases at a number of sites in the body including the joints¹⁴ and the gut.¹⁵

The study published in this issue of Thorax by Kranenburg and colleagues¹⁶ suggests that bronchial vascular changes may also occur in chronic obstructive …