Hoydal, M.A., Kaurstad, G., Rolim, N.P., Johnsen, A.B., Alves, M., Koch, L.G., Britton, S.L., Stolen, T.O., Smith, G.L. and Wisloff, U. (2013) High inborn aerobic capacity does not protect the heart following myocardial infarction. Journal of Applied Physiology, 115(12), pp. 1788-1795. (doi: 10.1152/japplphysiol.00312.2013)
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Abstract
Maximal oxygen uptake (V̇O2max) is a strong prognostic marker for morbidity and mortality, but the cardio-protective effect of high inborn V̇O2max remains unresolved. We aimed to investigate whether rats with high inborn V̇O2max yield cardio-protection after myocardial infarction (MI) compared with rats with low inborn V̇O2max. Rats breed for high capacity of running (HCR) or low capacity of running (LCR) were randomized into HCR-SH (sham), HCR-MI, LCR-SH, and LCR-MI. V̇O2max was lower in HCR-MI and LCR-MI compared with respective sham (P < 0.01), supported by a loss in global cardiac function, assessed by echocardiography. Fura 2-AM loaded cardiomyocyte experiments revealed that HCR-MI and LCR-MI decreased cardiomyocyte shortening (39%, and 34% reduction, respectively, both P < 0.01), lowered Ca2+ transient amplitude (37%, P < 0.01, and 20% reduction, respectively), and reduced sarcoplasmic reticulum (SR) Ca2+ content (both; 20%, P < 0.01) compared with respective sham. Diastolic Ca2+ cycling was impaired in HCR-MI and LCR-MI evidenced by prolonged time to 50% Ca2+ decay that was partly explained by the 47% (P <0.01) and 44% (P < 0.05) decrease in SR Ca2+-ATPase Ca2+ removal, respectively. SR Ca2+ leak increased by 177% in HCR-MI (P < 0.01) and 67% in LCR-MI (P < 0.01), which was abolished by inhibition of Ca2+/calmodulin-dependent protein kinase II. This study demonstrates that the effect of MI in HCR rats was similar or even more pronounced on cardiac- and cardiomyocyte contractile function, as well as on Ca2+ handling properties compared with observations in LCR. Thus our data do not support a cardio-protective effect of higher inborn aerobic capacity.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Smith, Professor Godfrey |
Authors: | Hoydal, M.A., Kaurstad, G., Rolim, N.P., Johnsen, A.B., Alves, M., Koch, L.G., Britton, S.L., Stolen, T.O., Smith, G.L., and Wisloff, U. |
College/School: | College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health |
Journal Name: | Journal of Applied Physiology |
ISSN: | 8750-7587 |
ISSN (Online): | 1522-1601 |
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