title: Investigations on the renin-angiotensin system in acute severe asthma.
abstract: The renin-angiotensin system is activated in acute severe asthma. The precise mechanism of activation is at present unknown, but may involve, beta2-agonists, catecholamines or proteases released in airway inflammation. This study aims to identify potential factors involved in the activation of the renin-angiotensin system in acute asthma. Forty asthmatics with severe exacerbations of asthma, assessed by measurement of peak expiratory flow rate (mean (SD) 35 (18)% predicted), oxygen saturation (94 (4)%) and pulse rate (108 (16) beats x min(-1)) were recruited. Nineteen (48%) asthmatics had elevated plasma angiotensin II levels (median (interquartile range) 10.9 (4.3-23.5) pg x mL(-1) (normal range 3-12 pg x mL(-1))) and 10 (25%) had elevated plasma renin concentration (22.0 (10.0-50.0) microU x mL(-1) (normal range 9-50 microU x mL(-1))). Plasma renin and angiotensin II correlated strongly, implying renin-dependent angiotensin II formation. No correlation was found between plasma salbutamol, adrenaline, nor-adrenaline, endothelin-1, histamine, eosinophilic cationic protein, serum angio-tensin-converting enzyme (ACE) activity, total immunoglobulin E (IgE), urea and electrolytes, indicators of the severity of the attack, atopic status, blood pressure and renin or angiotensin II levels. We conclude that although a subpopulation of asthmatics appear to have raised renin and angiotensin II during attacks of acute, severe asthma, the mechanism of activation of the renin-angiotensin system remains unclear.
authors.affiliation: Dept of Respiratory Medicine, Western Infirmary, Glasgow, Scotland, UK.
authors.forename: S G
authors.initials: SG
authors.lastname: Ramsay
authors.forename: K D
authors.initials: KD
authors.lastname: Dagg
authors.forename: I C
authors.initials: IC
authors.lastname: McKay
authors.forename: B J
authors.initials: BJ
authors.lastname: Lipworth
authors.forename: C
authors.initials: C
authors.lastname: McSharry
authors.forename: N C
authors.initials: NC
authors.lastname: Thomson
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000804:Angiotensin II / Q000097:blood*; D001249:Asthma / Q000097:blood / Q000201:enzymology / Q000503:physiopathology*; D002395:Catecholamines / Q000097:blood; D019332:Endothelin-1 / Q000097:blood; D005260:Female; D005541:Forced Expiratory Volume; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010366:Peak Expiratory Flow Rate; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D002395:Catecholamines; D019332:Endothelin-1; D000804:Angiotensin II; D007703:Peptidyl-Dipeptidase A; D012083:Renin