Document Detail

Circulating surfactant protein-B levels increase acutely in response to exercise-induced left ventricular dysfunction.
MedLine Citation:
PMID:  16120188     Owner:  NLM     Status:  MEDLINE    
1. As a result of its enormous surface area and necessary thinness for gas exchange, the alveolocapillary barrier is vulnerable to mechanical disruption from raised pulmonary microvascular pressure (Pmv). 2. Because surfactant protein-B (SP-B) leaks into the blood stream from the alveoli in response to alveolocapillary barrier damage and exercise leads to increased Pmv, we sought to determine whether exercise results in increased plasma SP-B. Moreover, in the setting of exercise-induced left ventricular dysfunction, the consequent increase in left heart filling pressure and, therefore, P(mv) would be expected to further increase plasma SP-B levels. 3. Twenty consecutive subjects referred for treadmill exercise stress echocardiography (ESE) had venous blood sampled immediately before and after ESE for batch atrial natriuretic peptide (ANP) and SP-B assay. Echocardiographic measures of pulmonary haemodynamics (pulmonary artery flow acceleration time (pafAT) and right ventricular outflow tract velocity time integral (rVTI)) were also taken pre- and post-exercise. 4. Although circulating ANP levels increased following exercise (P < 0.001), there was no change in circulating SP-B levels in the entire cohort. 5. Ten subjects had a positive ESE for ventricular dysfunction. Although circulating ANP was increased post-exercise in both the negative and positive ESE groups (P < 0.05 and P < 0.01, respectively), circulating SP-B only increased post-exercise in the positive ESE group (P < 0.05). Echocardiographic parameters supported an increment in P(mv) in the cohort with exercise-induced left ventricular dysfunction because this group had an increase in pafAT (P < 0.05; reflecting pulmonary artery pressure) and no change in rVTI. 6. Physical exertion associated with a Bruce protocol ESE is insufficient to increase circulating SP-B, despite evidence of increased left atrial and pulmonary vascular pressure. However, in the setting of exercise-induced myocardial dysfunction, there is a detectable increase in circulating SP-B. 7. The exaggerated increase in pulmonary vascular pressure in exercise-induced myocardial dysfunction may result in increased SP-B leakage from the alveoli into the circulation by altering the integrity of the alveolocapillary barrier to protein.
Carmine G De Pasquale; Leonard F Arnolda; Ian R Doyle; Phillip E Aylward; Andrew E Russell; Andrew D Bersten
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  32     ISSN:  0305-1870     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-08-25     Completed Date:  2005-10-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  Australia    
Other Details:
Languages:  eng     Pagination:  622-7     Citation Subset:  IM    
Cardiac Services, Flinders Medical Centre, Adelaide, South Australia, Australia.
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MeSH Terms
Atrial Natriuretic Factor / blood*
Exercise / physiology*
Middle Aged
Myocardial Ischemia / physiopathology
Pulmonary Surfactant-Associated Protein B / blood*
Ventricular Dysfunction, Left / blood,  physiopathology*
Reg. No./Substance:
0/Pulmonary Surfactant-Associated Protein B; 85637-73-6/Atrial Natriuretic Factor

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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