Impact of gender on the myocardial metabolic response to obesity.
OBJECTIVE
We sought to determine the gender-specific effects of obesity on myocardial metabolism, work, and efficiency.


BACKGROUND
Myocardial metabolism abnormalities may contribute to the development of obesity-related heart failure. Increased myocardial oxygen consumption (MVO(2)) and fatty acid (FA) metabolism and decreased efficiency occur with obesity in women. It is unknown whether similar changes occur with obesity in men.


METHODS
We quantified cardiac work, efficiency, myocardial blood flow (MBF), MVO(2), glucose, and FA metabolism with echocardiography and positron emission tomography in nonobese and obese men and women (N = 86).


RESULTS
There were significant differences between the obese (n = 35) and nonobese (n = 51) subjects in age, body composition, plasma lipids, and insulin resistance in addition to differences between the men (n = 30) and women (n = 56) in body composition and plasma lipids. Female gender independently predicted increased cardiac work (p < 0.001). Female gender also related to lower efficiency (p < 0.05). Obesity and female gender independently predicted greater MBF (p < 0.01, p < 0.0005, respectively) and MVO(2) (p < 0.0005, p < 0.0001). Myocardial glucose uptake was not different among the 4 subject groups, but obesity and gender interacted in predicting glucose uptake (p < 0.05). Lower myocardial glucose utilization was independently predicted by female gender (p < 0.05), and it independently predicted lower myocardial glucose utilization/plasma insulin (p < 0.05). Obesity and gender significantly interacted in the determination of glucose utilization/plasma insulin (p = 0.01). There were no differences in FA uptake among the 4 groups, and although increasing obesity correlated with greater myocardial FA utilization and oxidation; female gender (p < 0.005, p < 0.01) and plasma triglycerides (p < 0.05, p < 0.005) were their independent predictors.


CONCLUSIONS
Women's and men's myocardial metabolic responses to obesity are not exactly the same. Obesity and gender modulate MBF and MVO(2), are related to myocardial substrate metabolism, and sometimes interact in its prediction. Gender modifies efficiency. Gender-related differences in myocardial metabolism may affect the development of/adaptation to obesity-related cardiac disease.
Peterson
Linda R
LR
Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA. lpeterso@im.wustl.edu
Soto
Pablo F
PF
Herrero
Pilar
P
Mohammed
B Selma
BS
Avidan
Michael S
MS
Schechtman
Kenneth B
KB
Dence
Carmen
C
Gropler
Robert J
RJ
D000222:Adaptation, Physiological; D000328:Adult; D003326:Coronary Circulation; D015150:Echocardiography, Doppler; D004734:Energy Metabolism; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D006333:Heart Failure / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009765:Obesity / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D010101:Oxygen Consumption; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D012737:Sex Factors; D016277:Ventricular Function, Left; D055815:Young Adult
D005227:Fatty Acids; D007328:Insulin; D005947:Glucose