Document Detail


Effect of post-myocardial infarction exercise training on the renin-angiotensin-aldosterone system and cardiac function.
MedLine Citation:
PMID:  18030183     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
After a myocardial infarction (MI), the injured heart undergoes intensive remodeling characterized by activation of the circulating renin-angiotensin-aldosterone system (RAAS), left ventricular (LV) dilation, and contractile dysfunction. Exercise training may attenuate activation of the RAAS and improve myocardial remodeling. In this study, we investigated whether starting exercise training early or late after MI would have different effect on circulating RAAS and LV dilation and function. Male Sprague-Dawley rats (7 weeks old) underwent surgically induced MI. After surgery, rats were matched for similar infarct sizes and assigned into two major groups, based on the designated starting time of exercise training. Exercise groups started exercise at either 1 or 6 weeks after MI and exercised on a treadmill for 8 weeks. Groups starting exercise 1 week after MI included sham-operated control (1Wk-Sham), MI-ksedentary (1Wk-MI-Sed), and MI-exercise (1Wk-MI-Ex). Groups starting exercise 6 weeks after MI included sham-operated control (6Wk-Sham), MI-sedentary (6Wk-MI-Sed), and MI-exercise (6Wk-MI-Ex). An echocardiogram was performed before and after exercise training. Blood samples were obtained at the end of experiments. The results showed that compared with sedentary rats with MI, exercise training significantly attenuated circulating renin, angiotensin converting enzyme, angiotensin II, and aldosterone. Rats in exercise groups had similar LV end-diastolic diameters compared with their sedentary counterparts and tended to have smaller LV end-systolic diameters, and percent fractional shortening in exercise rats was significantly higher than in sedentary rats. These findings suggest that exercise training does not cause LV dilation and preserves LV function. Post-MI exercise training also normalizes the circulating RAAS, and this effect is independent of timing of post-MI exercise. Exercise starting early or late after MI affects myocardial remodeling and function similarly, suggesting that early exercise training may attenuate activation of the RAAS and preserve cardiac function early after MI.
Authors:
Wenhan Wan; Anthony S Powers; Ji Li; Lisa Ji; John M Erikson; John Q Zhang
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of the medical sciences     Volume:  334     ISSN:  0002-9629     ISO Abbreviation:  Am. J. Med. Sci.     Publication Date:  2007 Oct 
Date Detail:
Created Date:  2007-11-21     Completed Date:  2007-12-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370506     Medline TA:  Am J Med Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  265-73     Citation Subset:  AIM; IM    
Affiliation:
Laboratory of Cardiovascular Research, University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Citrate (si)-Synthase / metabolism
Disease Models, Animal
Heart / physiology*
Male
Muscle, Skeletal / enzymology
Myocardial Infarction / physiopathology,  rehabilitation*
Physical Conditioning, Animal*
Rats
Rats, Sprague-Dawley
Renin-Angiotensin System / physiology*
Time Factors
Ventricular Function, Left / physiology
Ventricular Remodeling / physiology
Grant Support
ID/Acronym/Agency:
R01 HL 074273/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
EC 2.3.3.1/Citrate (si)-Synthase

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


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