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Substrate Utilization Effects on Shortening Properties in Aging Cardiac Myocytes
Author(s) -
Barton Greg,
Aiken Judd,
Diffee Gary
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1049.4
Subject(s) - myocyte , medicine , contraction (grammar) , endocrinology , substrate (aquarium) , metabolism , cardiac function curve , cardiology , chemistry , biology , heart failure , ecology
Aging is associated with declining cardiac contractile function as well as changes in substrate metabolism and mitochondrial function. The relationship between age‐related changes in cardiac metabolism and declining cardiac contractile function has not been determined. We explored the role of alterations in substrate metabolism on age‐related changes in contractile function of isolated left ventricular myocytes from Young (Y) and Old (O) FBN rats. Single, intact myocytes were stimulated for ten minutes of continuous contraction at either2Hz or 4Hz while being perfused with Ringers solution containing either Glucose (11mM) or Oleate (0.4mM) as the fuel substrate. Properties of shortening (% and rate of shortening) were measured at the onset (T0) and after 10 minutes (T10) of continuous contraction, and the decline in shortening over time (T10/T0) was determined at each workload. Myocytes from Y hearts generally had better contractile function when glucose was the substrate, with a smaller workload‐dependent decline in function, compared to when oleate was the substrate. In aged myocytes, the opposite was true, with O myocytes showing less workload‐dependent decline in percent shortening and rate of shortening when oleate was the substrate. This data suggests that when forced to use only one substrate, myocytes from young hearts are better able to use glucose, while cells from old hearts are better able to metabolize oleate. Supported by NIH AG030423