Altered myocardial fatty acid and glucose metabolism in idiopathic dilated cardiomyopathy.
OBJECTIVE
The purpose of this study was to determine whether patients with idiopathic dilated cardiomyopathy (IDCM) exhibit alterations in myocardial fatty acid and glucose metabolism.


BACKGROUND
Alterations in myocardial metabolism have been implicated in the pathogenesis of heart failure (HF); however, studies of myocardial metabolic function in human HF have yielded conflicting results. Animal models of HF have shown a downregulation of the expression of enzymes of fatty acid beta-oxidation that recapitulates the fetal energy metabolic program, in which fatty acid metabolism is decreased and glucose metabolism is increased.


METHODS
Seven patients with IDCM (mean left ventricular ejection fraction 27 +/- 8%) and 12 normal controls underwent positron emission tomography for measurements of myocardial blood flow (MBF), myocardial oxygen consumption (MVO(2)), myocardial glucose utilization (MGU), myocardial fatty acid utilization (MFAU) and myocardial fatty acid oxidation (MFAO).


RESULTS
The systolic and diastolic blood pressures, plasma substrates and insulin levels, MBF and MVO(2), were similar between groups. The rates of MFAU and MFAO were significantly lower in IDCM than in the normal control group (MFAU: 134 +/- 44 vs. 213 +/- 49 nmol/g/min, p = 0.003; and MFAO: 113 +/- 50 vs. 205 +/- 49 nmol/g/min, p = 0.001) and the rates of MGU were significantly higher in IDCM than the normal control group (MGU: 247 +/- 63 vs. 125 +/- 64 nmol/g/min, p < 0.001).


CONCLUSIONS
Patients with IDCM exhibit alterations in myocardial metabolism characterized by decreased fatty acid metabolism and increased myocardial glucose metabolism, a pattern similar to that shown in animal models of HF. Whether alterations in myocardial metabolism constitute an adaptive response or mediate the development of HF remains to be determined.
Dávila-Román
Víctor G
VG
Cardiovascular Imaging and Clinical Research Core Laboratory, Cardiovascular Division, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA. vdavila@im.wustl.edu
Vedala
Giridhar
G
Herrero
Pilar
P
de las Fuentes
Lisa
L
Rogers
Joseph G
JG
Kelly
Daniel P
DP
Gropler
Robert J
RJ
D000328:Adult; D002250:Carbon Radioisotopes; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000378:metabolism*; D016022:Case-Control Studies; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D011877:Radionuclide Imaging
D002250:Carbon Radioisotopes; D005227:Fatty Acids; D005947:Glucose