Bronchial Circulation in Asthma

Abstract

Whereas the anatomical changes of the bronchial circulation in response to a wide variety of congenital and acquired cardiopulmonary diseases have been well described, little is known about its functional response. There is growing evidence that the bronchial circulation plays a major role in the pathophysiology of hyperreactive airway disease. The bronchial vascular system appears to be involved in mediator transport to and from target tissues in the airway wall, in the development of airway wall edema which may contribute to airflow obstruction, and in heat and water exchange in the tracheobronchial tree. Although our current understanding of these functions is rather sketchy, enough is known to outline the contributions of the bronchial, i.e. the systemic circulation to the mechanisms of bronchial asthma.

Parasympathetic nervous control of tracheal vascular resistance in the dog.

“…Whether or not parasympathetic cholinergic fibres to the airway vasculature can cause relaxation is more controversial, and in general histological studies do not support a close cholinergic innervation of the vessels. However, the subject has probably not been adequately studied (Baier, Long & Wanner, 1985; Laitinen, Laitinen & Widdicombe, 1986b).…”

Dose‐related effects of pharmacological mediators on tracheal vascular resistance in dogs

“…In addition to providing nutrition to the lungs, the bronchial vessels play significant roles in controlling the clearance of chemical mediators, in regulating the development of airway wall oedema, and in controlling heat exchange in the tracheobronchial tree (Baier et al, 1985). The bronchial vessels can also function as a haemodynamic and gas-exchange system due to anastomoses with the pulmonary arteries.…”

Receptors mediating the effects of 5‐hydroxytryptamine on the tracheal vasculature and smooth muscle of sheep

“…The tracheobronchial circulation plays a major role in providing nutrition to the lower airways. Bronchial and tracheal vessels may also control the distribution and clearance of chemical mediators and inhaled bronchodilators from the airways, regulate the development of airway wall oedema and control heat exchange in the tracheobronchial tree (Baier et al, 1985;Deffebach et al, 1987).…”