Document Detail


Impact of aging on muscle blood flow in chronic heart failure.
MedLine Citation:
PMID:  15802367     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Chronic heart failure (CHF) is manifested principally in the elderly population. Therefore, to understand the causes of exercise intolerance in CHF patients, it is imperative to resolve the effects of aging on muscle blood flow (BF) in CHF. To address this issue, we determined the muscle BF response to submaximal treadmill exercise (20 m/min, 5% grade) in young (Y(CHF): 6-8 mo, 412 +/- 11 g, n = 11) and old (O(CHF): 27-29 mo, 494 +/- 10 g, n = 8) Fischer 344 x Brown Norway rats with similar degrees of myocardial infarction-induced left ventricular (LV) dysfunction [resting LV end-diastolic pressure: Y(CHF) = 24 +/- 2, O(CHF) = 22 +/- 2 mmHg; derivative of LV pressure over time: Y(CHF) = 5,168 +/- 285; O(CHF) = 5,050 +/- 165 mmHg/s; lung weight normalized to body weight: Y(CHF) = 9.14 +/- 0.72; O(CHF) = 8.21 +/- 0.29 mg/g (all P > 0.05)]. The exercising heart rate response was blunted in O(CHF) compared with Y(CHF) rats (Y(CHF) = 454 +/- 8, O(CHF) = 395 +/- 9 beats/min; P < 0.05). BF (radiolabeled microspheres) to the total hindlimb musculature and to each of the 28 individual muscles examined was similar between Y(CHF) and O(CHF) rats under resting conditions. During exercise, BF to five of the hindlimb muscles that normally possess a majority of slow-twitch oxidative and fast-twitch oxidative glycolytic muscle fibers increased significantly less (-25 to -42%) for O(CHF) compared with Y(CHF) rats. In contrast, BF to 14 of the hindlimb muscles that normally possess a majority of fast-twitch glycolytic muscle fibers was increased (+22 to +337%) for O(CHF) vs. Y(CHF) rats, which contributed to a greater mass-specific total hindlimb BF response in O(CHF) rats (Y(CHF) = 78 +/- 5, O(CHF) = 100 +/- 11 ml.min(-1).100 g(-1); P < 0.05) and coincided with greater reductions in BF to the kidneys and splanchnic organs during exercise in O(CHF) vs. Y(CHF). In conclusion, there appears to be a profound age-related redistribution of BF from the highly oxidative to the highly glycolytic muscles of the hindlimb during exercise in O(CHF) compared with Y(CHF) rats. This phenomenon is qualitatively similar to that reported previously for healthy young and old rats.
Authors:
Kevin E Eklund; K Sue Hageman; David C Poole; Timothy I Musch
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2005-03-31
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  99     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-07-15     Completed Date:  2005-09-30     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  505-14     Citation Subset:  IM    
Affiliation:
Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, 128 Coles Hall, 1600 Denison Avenue, Manhattan, KS 66505-5802, USA.
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MeSH Terms
Descriptor/Qualifier:
Aging*
Animals
Blood Flow Velocity*
Chronic Disease
Exercise Test
Heart Failure / physiopathology*
Muscle Fibers, Skeletal*
Muscle, Skeletal / blood supply*,  physiopathology*
Physical Exertion*
Rats
Rats, Inbred F344
Grant Support
ID/Acronym/Agency:
AG 19228/AG/NIA NIH HHS; HL 50306/HL/NHLBI NIH HHS

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