TY - JOUR
T1 - The progressive effects of a fat enriched diet on ventricular myocyte contraction and intracellular Ca2+ in the C57BL/6J mouse
AU - Howarth, F. Chris
AU - Qureshi, M. A.
AU - Gbewonyo, A. J.
AU - Tariq, S.
AU - Adeghate, E.
N1 - Funding Information:
This study was supported by a Grant from the United Arab Emirates University.
PY - 2005/5
Y1 - 2005/5
N2 - The C57BL/6J mouse has a genetic susceptibility to develop diabetes when fed with a high-fat, high-sucrose diet. The general characteristics of diet-induced diabetes in this model include progressive development of hyperinsulinaemia, hyperglycaemia, insulin resistance and obesity, features that are frequently observed in the clinical setting. This study investigated the progressive effects of a fat enriched (FE) diet on contraction and intracellular Ca2+ in ventricular myocytes from the C57BL/6J mouse. The characteristics of the mice fed with the FE diet compared to mice receiving control diet included progressive increase in the rate of body weight gain, increased fasting blood glucose and time-dependent differences in the disposal of blood glucose after a glucose challenge. The ultrastructure of cardiac myocytes and associated capillaries did not show any gross morphological alteration after 27 weeks of FE diet compared to controls. At 5 months the resting cell length (RCL) and the kinetics of shortening were not significantly altered in ventricular myocytes from mice receiving the FE diet compared to age-matched controls. At 5 and at 7 months the amplitude of shortening was increased in myocytes receiving the FED diet compared to controls. At 7 months the time to half (THALF) relaxation of myocyte contraction was shortened in myocytes from mice receiving the FE diet compared to controls. Mean THALF relaxation in myocytes from mice fed the FE diet was 32.0 ± 1.4 ms (n = 23) compared to 40.2 ± 2.0 ms (n = 27) in controls. Neither resting intracellular a2+ nor the kinetics or amplitude of the Ca2+ transient were altered by FE diet. Differences in myofilament sensitivity to Ca2+ might underlie the changes in contractility.
AB - The C57BL/6J mouse has a genetic susceptibility to develop diabetes when fed with a high-fat, high-sucrose diet. The general characteristics of diet-induced diabetes in this model include progressive development of hyperinsulinaemia, hyperglycaemia, insulin resistance and obesity, features that are frequently observed in the clinical setting. This study investigated the progressive effects of a fat enriched (FE) diet on contraction and intracellular Ca2+ in ventricular myocytes from the C57BL/6J mouse. The characteristics of the mice fed with the FE diet compared to mice receiving control diet included progressive increase in the rate of body weight gain, increased fasting blood glucose and time-dependent differences in the disposal of blood glucose after a glucose challenge. The ultrastructure of cardiac myocytes and associated capillaries did not show any gross morphological alteration after 27 weeks of FE diet compared to controls. At 5 months the resting cell length (RCL) and the kinetics of shortening were not significantly altered in ventricular myocytes from mice receiving the FE diet compared to age-matched controls. At 5 and at 7 months the amplitude of shortening was increased in myocytes receiving the FED diet compared to controls. At 7 months the time to half (THALF) relaxation of myocyte contraction was shortened in myocytes from mice receiving the FE diet compared to controls. Mean THALF relaxation in myocytes from mice fed the FE diet was 32.0 ± 1.4 ms (n = 23) compared to 40.2 ± 2.0 ms (n = 27) in controls. Neither resting intracellular a2+ nor the kinetics or amplitude of the Ca2+ transient were altered by FE diet. Differences in myofilament sensitivity to Ca2+ might underlie the changes in contractility.
KW - Contraction
KW - Diabetes mellitus
KW - Diet
KW - Heart
KW - Intracellular calcium
KW - Ventricular myocytes
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U2 - 10.1007/s11010-005-7758-6
DO - 10.1007/s11010-005-7758-6
M3 - Article
C2 - 16013443
AN - SCOPUS:20044363482
SN - 0300-8177
VL - 273
SP - 87
EP - 95
JO - Molecular and cellular biochemistry
JF - Molecular and cellular biochemistry
IS - 1-2
ER -