Measurement of myocardial fatty acid esterification using [1-11C]palmitate and PET: comparison with direct measurements of myocardial triglyceride synthesis.
BACKGROUND
The purpose of the present study was to assess the accuracy of rates of myocardial fatty acid esterification (MFAE) obtained using positron emission tomography (PET).


RESULTS
Sixteen dogs were studied after an overnight fast (FAST), during a euglycemic hyperinsulinemic clamp (CLAMP), or during infusion of intralipid (IL) or IL plus dobutamine (IL/DOB). MFAE was quantified using [1-(11)C]palmitate and PET and compared to the rate of triglyceride (TG) synthesis measured using [1-(13)C]palmitate and tissue sampling. Plasma free fatty acid (FFA) concentration varied approximately 20-fold across groups, with this variation in FFA availability accompanied by a approximately 20-fold range in TG synthesis. MFAE varied approximately 12-fold across groups, and was significantly correlated with TG synthesis (R = 0.80, P < .001). MFAE, however, was 3- to 4-fold higher than TG synthesis in FAST, CLAMP, and IL, but only approximately 50% higher when cardiac work was increased in IL/DOB, suggesting that MFAE reflects, in part, the incorporation of label into amino acids via TCA cycle exchange reactions.


CONCLUSIONS
Changes in MFAE parallel changes in TG synthesis, at least in the basal state. Although the data need to be interpreted cautiously, such measurements should be useful for quantifying acute changes in FFA storage by the heart in various pathophysiological states.
Coggan
Andrew R
AR
Division of Radiological Sciences, Cardiovascular Imaging Laboratory, Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St. Louis, MO 63110, USA. coggana@mir.wustl.edu
Kisrieva-Ware
Zulfia
Z
Dence
Carmen S
CS
Eisenbeis
Paul
P
Gropler
Robert J
RJ
Herrero
Pilar
P
D000818:Animals; D002250:Carbon Radioisotopes; D004280:Dobutamine / Q000378:metabolism; D004285:Dogs; D004952:Esters; D005227:Fatty Acids / Q000378:metabolism*; D006946:Hyperinsulinism; D007700:Kinetics; D008055:Lipids / Q000737:chemistry; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry; D019308:Palmitic Acid / Q000737:chemistry*; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D014280:Triglycerides / Q000378:metabolism*
D002250:Carbon Radioisotopes; D004952:Esters; D005227:Fatty Acids; D008055:Lipids; D014280:Triglycerides; D019308:Palmitic Acid; D004280:Dobutamine; D010100:Oxygen