Cardiac hypertrophy by hypertension and exercise training exhibits different gene expression of enzymes in energy metabolism.
Hypertension-induced pathological cardiac hypertrophy (hypertensive heart) and exercise training-induced physiological cardiac hypertrophy (athletic heart) have differences in cardiac properties. We hypothesized that gene expression of energy metabolic enzymes differs between these two types of cardiac hypertrophy. To investigate whether mRNA expression of key enzymes in the long-chain fatty acid (FA), glucose, and lactic acid metabolic pathways differs between these two types of cardiac hypertrophy, we used the hearts of spontaneously hypertensive rats (SHR; 19 weeks old) as a model of the hypertensive heart, swim-trained rats (Trained; 19 weeks old, swimming training for 15 weeks) as a model of the athletic heart, and sedentary Wistar-Kyoto rats (Control; 19 weeks old). SHR developed hypertensive cardiac hypertrophy, of which cardiac function was deteriorated, whereas Trained rats developed an athletic heart, of which cardiac function was enhanced. The mRNA expression of CD36, which involved in uptake of long-chain FA, in the heart was almost never detected in the SHR group. Furthermore, the mRNA expression of key enzymes in the long-chain FA metabolic pathway (acyl CoA synthase [ACoAS], carnitine palmitoyl transferase [CPT]-I, CPT-II, and isocitrate dehydrogenase [ISCD]) in the heart was significantly higher in the SHR group compared with the Control group. The mRNA expression of ACoAS, CPT-I, ISCD, and CD36 in the heart did not differ between Trained group and Control group, whereas that of CPT-II in the Trained group was significantly higher compared with the Control group. The mRNA expression of key enzymes (phosphofructokinase and lactate dehydrogenase) in glycolytic metabolic pathway in the heart was markedly higher in the SHR group compared with the Control group, whereas these mRNA expressions did not differ between Trained group and Control group. These findings suggest that the molecular phenotypes in the energy metabolic system differ in hypertension-induced pathological and exercise training-induced physiological cardiac hypertrophy, and these differences may participate in the differences in cardiac function.
Iemitsu
Motoyuki
M
Cardiovascular Division, Department of Internal Medicine, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan.
Miyauchi
Takashi
T
Maeda
Seiji
S
Sakai
Satoshi
S
Fujii
Nobuharu
N
Miyazaki
Hitoshi
H
Kakinuma
Yoshihiko
Y
Matsuda
Mitsuo
M
Yamaguchi
Iwao
I
D000818:Animals; D018955:CD36 Antigens / Q000235:genetics; D006332:Cardiomegaly / Q000378:metabolism / Q000503:physiopathology*; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics; D003066:Coenzyme A Ligases / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006973:Hypertension / Q000378:metabolism / Q000503:physiopathology*; D007521:Isocitrate Dehydrogenase / Q000235:genetics; D007770:L-Lactate Dehydrogenase / Q000235:genetics; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D010805:Physical Conditioning, Animal; D005082:Physical Exertion; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013550:Swimming
D018955:CD36 Antigens; D005227:Fatty Acids; D012333:RNA, Messenger; D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D002334:Carnitine O-Palmitoyltransferase; D003066:Coenzyme A Ligases