TY - JOUR
T1 - Effect of Obesity and Insulin Resistance on Myocardial Substrate Metabolism and Efficiency in Young Women
AU - Peterson, Linda R.
AU - Herrero, Pilar
AU - Schechtman, Kenneth B.
AU - Racette, Susan B.
AU - Waggoner, Alan D.
AU - Kisrieva-Ware, Zulia
AU - Dence, Carmen
AU - Klein, Samuel
AU - Marsala, Jo Ann
AU - Meyer, Timothy
AU - Gropler, Robert J.
PY - 2004/5/11
Y1 - 2004/5/11
N2 - Background-Obesity is a risk factor for impaired cardiac performance, particularly in women. Animal studies suggest that alterations in myocardial fatty acid metabolism and efficiency in obesity can cause decreased cardiac performance. In the present study, we tested the hypothesis that myocardial fatty acid metabolism and efficiency are abnormal in obese women. Methods and Results-We studied 31 young women (body mass index [BMI] 19 to 52 kg/m 2); 19 were obese (BMI >30 kg/m2). Myocardial oxygen consumption (MV̇o2) and fatty acid uptake (MFAUp), utilization (MFAU), and oxidation (MFAO) were quantified by positron emission tomography. Cardiac work was measured by echocardiography, and efficiency was calculated as work/MV̇o2. BMI correlated with MV̇o2 (r=0.58, P=0.0006), MFAUp (r=0.42, P<0.05), and efficiency (r= -0.40, P < 0.05). Insulin resistance, quantified by the glucose area under the curve (AUC) during an oral glucose tolerance test, correlated with MFAUp (r=0.55, P<0.005), MFAU (r=0.62, P<0.001), and MFAO (r=0.58, P<0.005). A multivariate, stepwise regression analysis showed that BMI was the only independent predictor of MV̇o2 and efficiency (P=0.0005 and P<0.05, respectively). Glucose AUC was the only independent predictor of MFAUp, MFAU, and MFAO (P<0.05, <0.005, and <0.005, respectively). Conclusions-In young women, obesity is a significant predictor of increased MV̇o2 and decreased efficiency, and insulin resistance is a robust predictor of MFAUp, MFAU, and MFAO. This increase in fatty acid metabolism and decrease in efficiency is concordant with observations made in experimental models of obesity. These metabolic changes may play a role in the pathogenesis of decreased cardiac performance in obese women.
AB - Background-Obesity is a risk factor for impaired cardiac performance, particularly in women. Animal studies suggest that alterations in myocardial fatty acid metabolism and efficiency in obesity can cause decreased cardiac performance. In the present study, we tested the hypothesis that myocardial fatty acid metabolism and efficiency are abnormal in obese women. Methods and Results-We studied 31 young women (body mass index [BMI] 19 to 52 kg/m 2); 19 were obese (BMI >30 kg/m2). Myocardial oxygen consumption (MV̇o2) and fatty acid uptake (MFAUp), utilization (MFAU), and oxidation (MFAO) were quantified by positron emission tomography. Cardiac work was measured by echocardiography, and efficiency was calculated as work/MV̇o2. BMI correlated with MV̇o2 (r=0.58, P=0.0006), MFAUp (r=0.42, P<0.05), and efficiency (r= -0.40, P < 0.05). Insulin resistance, quantified by the glucose area under the curve (AUC) during an oral glucose tolerance test, correlated with MFAUp (r=0.55, P<0.005), MFAU (r=0.62, P<0.001), and MFAO (r=0.58, P<0.005). A multivariate, stepwise regression analysis showed that BMI was the only independent predictor of MV̇o2 and efficiency (P=0.0005 and P<0.05, respectively). Glucose AUC was the only independent predictor of MFAUp, MFAU, and MFAO (P<0.05, <0.005, and <0.005, respectively). Conclusions-In young women, obesity is a significant predictor of increased MV̇o2 and decreased efficiency, and insulin resistance is a robust predictor of MFAUp, MFAU, and MFAO. This increase in fatty acid metabolism and decrease in efficiency is concordant with observations made in experimental models of obesity. These metabolic changes may play a role in the pathogenesis of decreased cardiac performance in obese women.
KW - Insulin
KW - Metabolism
KW - Obesity
UR - http://www.scopus.com/inward/record.url?scp=2442492971&partnerID=8YFLogxK
U2 - 10.1161/01.CIR.0000127959.28627.F8
DO - 10.1161/01.CIR.0000127959.28627.F8
M3 - Article
C2 - 15123530
AN - SCOPUS:2442492971
SN - 0009-7322
VL - 109
SP - 2191
EP - 2196
JO - Circulation
JF - Circulation
IS - 18
ER -