Evaluation of fatty acid metabolism in hearts after ischemia-reperfusion injury using a dual-isotope autoradiographic approach and tissue assay for metabolites of tracer.
We investigated whether changes in myocardial uptake of fatty acid tracer after reperfusion following transient myocardial ischemia were closely related to alterations in intracellular fatty acid oxidation.


METHODS
Using a fatty acid tracer of (131)I- and (125)I-labeled 15-(p-iodophenyl)-9-methylpentadecanoic acid (9MPA), the myocardial uptake and metabolites were determined by dual-tracer autoradiography and thin-layer chromatography in rats 3 or 14 d after reperfusion following 5 or 15 min of ischemia induced by coronary artery ligation.


RESULTS
9MPA metabolites processed via beta-oxidation were lower in the ischemic region (IR) than in non-IR 3 d after 5 min of ischemia, despite no reduction of tracer uptake in IR. Oxidation of 9MPA was recovered 14 d after 15 min of ischemia in association with normalization of tracer uptake in IR, whereas both uptake and oxidation of 9MPA were markedly impaired 3 d after 15 min of ischemia, accompanied by slow clearance of myocardial tracer.


CONCLUSIONS
Normal uptake of fatty acid tracer early after reperfusion does not always imply preserved intracellular fatty acid oxidation. However, reduction of tracer uptake might reflect impaired fatty acid oxidation.
Igarashi
Norio
N
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, Japan.
Nozawa
Takashi
T
Fujii
Nozomu
N
Kato
Bun-ichi
B
Nonomura
Makoto
M
Matsuki
Akira
A
Nakadate
Teruo
T
Igawa
Akihiko
A
Asanoi
Hidetsugu
H
Inoue
Minoru
M
Inoue
Hiroshi
H
D000818:Animals; D001345:Autoradiography / Q000379:methods; D005227:Fatty Acids / Q000378:metabolism / Q000493:pharmacokinetics*; D006321:Heart / Q000000981:diagnostic imaging*; D007462:Iodobenzenes / Q000493:pharmacokinetics*; D008657:Metabolic Clearance Rate; D009206:Myocardium / Q000378:metabolism*; D010084:Oxidation-Reduction; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000000981:diagnostic imaging* / Q000378:metabolism*
D005227:Fatty Acids; D007462:Iodobenzenes; D019275:Radiopharmaceuticals; C067799:4-iodophenyl-9-methylpentadecanoic acid